Geology and energy resources of the Sand Butte Rim NW Quadrangle, Sweetwater County, Wyoming

USGS Publications Warehouse

Roehler, Henry W.

1979-01-01

The Sand Butte Rim NW 71-minute quadrangle occupies 56 square miles of an arid, windy, sparsely vegetated area of ridges and valleys on the east flank of the Rock Springs uplift in southwest Wyoming. The area is underlain by a succession of sedimentary rocks, about 20,000 feet thick, that includes 28 formations ranging in age from Cambrian to Tertiary. Upper Cretaceous and lower Tertiary formations crop out and dip 3?-6? southeast. They are unfaulted and generally homoclinal, but a minor anticlinal nose is present. Older rocks in the subsurface are faulted and folded. Coal resources are estimated to be nearly I billion short tons of subbituminous coal, in beds more than 2.5 feet thick, under less than 3,000 feet of overburden, in the Fort Union Formation of Paleocene age and the Lance and Almond Formations of Cretaceous age.

Behavior of uranium under conditions of interaction of rocks and ores with subsurface water

NASA Astrophysics Data System (ADS)

Omel'Yanenko, B. I.; Petrov, V. A.; Poluektov, V. V.

2007-10-01

The behavior of uranium during interaction of subsurface water with crystalline rocks and uranium ores is considered in connection with the problem of safe underground insulation of spent nuclear fuel (SNF). Since subsurface water interacts with crystalline rocks formed at a high temperature, the mineral composition of these rocks and uranium species therein are thermodynamically unstable. Therefore, reactions directed toward the establishment of equilibrium proceed in the water-rock system. At great depths that are characterized by hindered water exchange, where subsurface water acquires near-neutral and reducing properties, the interaction is extremely sluggish and is expressed in the formation of micro- and nanoparticles of secondary minerals. Under such conditions, the slow diffusion redistribution of uranium with enrichment in absorbed forms relative to all other uranium species is realized as well. The products of secondary alteration of Fe- and Ti-bearing minerals serve as the main sorbents of uranium. The rate of alteration of minerals and conversion of uranium species into absorbed forms is slow, and the results of these processes are insignificant, so that the rocks and uranium species therein may be regarded as unaltered. Under reducing conditions, subsurface water is always saturated with uranium. Whether water interacts with rock or uranium ore, the equilibrium uranium concentration in water is only ≤10-8 mol/l. Uraninite ore under such conditions always remains stable irrespective of its age. The stability conditions of uranium ore are quite suitable for safe insulation of SNF, which consists of 95% uraninite (UO2) and is a confinement matrix for all other radionuclides. The disposal of SNF in massifs of crystalline rocks at depths below 500 m, where reducing conditions are predominant, is a reliable guarantee of high SNF stability. Under oxidizing conditions of the upper hydrodynamic zone, the rate of interaction of rocks with subsurface water increases by orders of magnitude and subsurface water is commonly undersaturated with uranium. Uranium absorbed by secondary minerals, particularly by iron hydroxides and leucoxene, is its single stable species under oxidizing conditions. The impact of oxygen-bearing water leads to destruction of uranium ore. This process is realized simultaneously at different hypsometric levels even if the permeability of the medium is variable in both the lateral and vertical directions. As a result, intervals containing uranyl minerals and relics of primary uranium ore are combined in ore-bearing zones with intervals of completely dissolved uranium minerals. A wide halo of elevated uranium contents caused by sorption is always retained at the location of uranium ore entirely destroyed by weathering. Uranium ore commonly finds itself in the aeration zone due to technogenic subsidence of the groundwater table caused by open-pit mining or pumping out of water from underground mines. The capillary and film waters that interact with rocks and ores in this zone are supplemented by free water filtering along fractures when rain falls or snow is thawing. The interaction of uranium ore with capillary water results in oxidation of uraninite, accompanied by loosening of the mineral surface, formation of microfractures, and an increase in solubility with enrichment of capillary water in uranium up to 10-4 mol/l. Secondary U(VI) minerals, first of all, uranyl hydroxides and silicates, replace uraninite, and uranium undergoes local diffusion redistribution with its sorption by secondary minerals of host rocks. The influx of free water facilitates the complete dissolution of primary and secondary uranium minerals, the removal of uranium at the sites of groundwater discharge, and its redeposition under reducing conditions at a greater depth. It is evident that the conditions of the upper hydrodynamic zone and the aeration zone are unfit for long-term insulation of SNF and high-level wastes because, after the failure of containers, the leakage of radionuclides into the environment becomes inevitable.

Preliminary biological sampling of GT3 and BT1 cores and the microbial community dynamics of existing subsurface wells

NASA Astrophysics Data System (ADS)

Kraus, E. A.; Stamps, B. W.; Rempfert, K. R.; Ellison, E. T.; Nothaft, D. B.; Boyd, E. S.; Templeton, A. S.; Spear, J. R.

2017-12-01

Subsurface microbial life is poorly understood but potentially very important to the search for life on other planets as well as increasing our understanding of Earth's geobiological processes. Fluids and rocks of actively serpentinizing subsurface environments are a recent target of biological study due to their apparent ubiquity across the solar system. Areas of serpentinization can contain high concentrations of molecular hydrogen, H2, that can serve as the dominant fuel source for subsurface microbiota. Working with the Oman Drilling Project, DNA and RNA were extracted from fluids of seven alkaline wells and two rock cores from drill sites GT3 and BT1 within the Samail ophiolite. DNA and cDNA (produced via reverse transcription from the recovered RNA) were sequenced using universal primers to identify microbial life across all three domains. Alkaline subsurface fluids support a microbial community that changes with pH and host-rock type. In peridotite with pH values of >11, wells NSHQ 14 and WAB 71 have high relative abundances of Meiothermus, Methanobacterium, the family Nitrospiraceae, and multiple types of the class Dehalococcoidia. While also hosted in peridotite but at pH 8.5, wells WAB 104 and 105 have a distinct, more diverse microbial community. This increased variance in community make-up is seen in wells that sit near/at the contact of gabbro and peridotite formations as well. Core results indicate both sampled rock types host a very low biomass environment subject to multiple sources of contamination during the drilling process. Suggestions for contaminant reduction, such as having core handlers wear nitrile gloves and flame-sterilizing the outer surfaces of core rounds for biological sampling, would have minimal impact to overall ODP coreflow and maximize the ability to better understand in situ microbiota in this low-biomass serpentinizing subsurface environment. While DNA extraction was successful with gram amounts of crushed rock, much can be done to improve yields and reduce contamination sources for Phase II drilling.

Mineral resource potential map of the Chama River Canyon Wilderness and contiguous roadless area, Rio Arriba County, New Mexico

USGS Publications Warehouse

Ridgley, Jennie L.; Light, Thomas D.

1983-01-01

The Chama River Canyon Wilderness and Roadless Area have a moderate to high potential for the presence of small deposits of copper with associated uranium and silver. These deposits, as yet undetected, would occur in the Permian Cutler Formation and in the lower part of the Triassic Chinle Formation, rock units that are, for the most part, present only in the subsurface. The presence of these deposits is inferred because such deposits occur in rocks of equivalent age in adjacent areas. Gypsum, of probable minable quality and quantity, occurs throughout the area. Oil and gas are possibly present in Pennsylvanian strata in the subsurface, although no drilling in the study area has tested this hypothesis. Other commodities, including noncopper-related uranium, kaolinite, chromium, vanadium, manganese, and bitumen, although present locally in anomalous concentrations, do not appear to constitute potential resources for these commodities.

Geo-material microfluidics at reservoir conditions for subsurface energy resource applications.

PubMed

Porter, Mark L; Jiménez-Martínez, Joaquín; Martinez, Ricardo; McCulloch, Quinn; Carey, J William; Viswanathan, Hari S

2015-10-21

Microfluidic investigations of flow and transport in porous and fractured media have the potential to play a significant role in the development of future subsurface energy resource technologies. However, the majority of experimental systems to date are limited in applicability due to operating conditions and/or the use of engineered material micromodels. We have developed a high pressure and temperature microfluidic experimental system that allows for direct observations of flow and transport within geo-material micromodels (e.g. rock, cement) at reservoir conditions. In this manuscript, we describe the experimental system, including our novel micromodel fabrication method that works in both geo- and engineered materials and utilizes 3-D tomography images of real fractures as micromodel templates to better represent the pore space and fracture geometries expected in subsurface formations. We present experimental results that highlight the advantages of using real-rock micromodels and discuss potential areas of research that could benefit from geo-material microfluidic investigations. The experiments include fracture-matrix interaction in which water imbibes into the shale rock matrix from etched fractures, supercritical CO2 (scCO2) displacing brine in idealized and realistic fracture patterns, and three-phase flow involving scCO2-brine-oil.

Geological and geochemical investigations of uranium occurrences in the Arrastre Lake area of the Medicine Bow Mountains, Wyoming

USGS Publications Warehouse

Miller, W. Roger; Houston, R.S.; Karlstrom, K.E.; Hopkins, D.M.; Ficklin, W.H.

1977-01-01

Metasedimentary rocks of Precambrian X age in and near the Snowy Range wilderness study area of southeastern Wyoming are lithologically and chronologically similar to those on the north shore of Lake Huron in Canada. The rocks in Canada contain major deposits of uranium in quartz-pebble conglomerates near the base of the metasedimentary sequence. Similar conglomerates in the Deep Lake Formation in the Medicine Bow Mountains of southeastern Wyoming are slightly radioactive and may contain deposits of uranium and other valuable heavy metals. During the summer of 1976, a geological and geochemical pilot study was conducted in the vicinity of Arrastre Lake in the Medicine Bow Mountains to determine the most effective exploration methods for evaluating the uranium potential of the Snowy Range wilderness study area. The area around Arrastre Lake was selected because of the presence of a radioactive lens within a quartz-pebble conglomerate of the Deep Lake Formation. The results of the survey indicate possible uranium mineralization in the subsurface rocks of this formation. The radon content of the dilute waters of the area is much higher than can be accounted for by the uranium content of the surface rocks. Two sources for the high content of the radon are possible. In either case, the high values of radon obtained in this study are a positive indication of uranium mineralization in the subsurface rocks. The determination of the radon content of water samples is the recommended geochemical technique for uranium exploration in the area. The determination of uranium in water and in organic-rich bog material is also recommended.

3D slicing of radiogenic heat production in Bahariya Formation, Tut oil field, North-Western Desert, Egypt.

PubMed

Al-Alfy, I M; Nabih, M A

2013-03-01

A 3D block of radiogenic heat production was constructed from the subsurface total gamma ray logs of Bahariya Formation, Western Desert, Egypt. The studied rocks possess a range of radiogenic heat production varying from 0.21 μWm(-3) to 2.2 μWm(-3). Sandstone rocks of Bahariya Formation have higher radiogenic heat production than the average for crustal sedimentary rocks. The high values of density log of Bahariya Formation indicate the presence of iron oxides which contribute the uranium radioactive ores that increase the radiogenic heat production of these rocks. The average radiogenic heat production produced from the study area is calculated as 6.3 kW. The histogram and cumulative frequency analyses illustrate that the range from 0.8 to 1.2 μWm(-3) is about 45.3% of radiogenic heat production values. The 3D slicing of the reservoir shows that the southeastern and northeastern parts of the study area have higher radiogenic heat production than other parts. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

System and method for investigating sub-surface features and 3D imaging of non-linear property, compressional velocity VP, shear velocity VS and velocity ratio VP/VS of a rock formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt

A system and a method for generating a three-dimensional image of a rock formation, compressional velocity VP, shear velocity VS and velocity ratio VP/VS of a rock formation are provided. A first acoustic signal includes a first plurality of pulses. A second acoustic signal from a second source includes a second plurality of pulses. A detected signal returning to the borehole includes a signal generated by a non-linear mixing process from the first and second acoustic signals in a non-linear mixing zone within an intersection volume. The received signal is processed to extract the signal over noise and/or signals resultingmore » from linear interaction and the three dimensional image of is generated.« less

Formation of an Anti-Core–Shell Structure in Layered Oxide Cathodes for Li-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hanlei; Omenya, Fredrick; Whittingham, M. Stanley

The layered → rock-salt phase transformation in the layered dioxide cathodes for Li-ion batteries is believed to result in a “core-shell” structure of the primary particles, in which the core region maintains as the layered phase while the surface region undergoes the phase transformation to the rock-salt phase. Using transmission electron microscopy, here we demonstrate the formation of an “anti-core-shell” structure in cycled primary particles with a formula of LiNi0.80Co0.15Al0.05O2, in which the surface and subsurface regions remain as the layered structure while the rock-salt phase forms as domains in the bulk with a thin layer of the spinel phasemore » between the rock-salt core and the skin of the layered phase. Formation of this anti-core-shell structure is attributed to the oxygen loss at the surface that drives the migration of oxygen from the bulk to the surface, thereby resulting in localized areas of significantly reduced oxygen levels in the bulk of the particle, which subsequently undergoes the phase transformation to the rock-salt domains. The formation of the anti-core-shell rock-salt domains is responsible for the reduced capacity, discharge voltage and ionic conductivity in cycled cathode.« less

Simulation and Characterization of Methane Hydrate Formation

NASA Astrophysics Data System (ADS)

Dhakal, S.; Gupta, I.

2017-12-01

The ever rising global energy demand dictates human endeavor to explore and exploit new and innovative energy sources. As conventional oil and gas reserves deplete, we are constantly looking for newer sources for sustainable energy. Gas hydrates have long been discussed as the next big energy resource to the earth. Its global occurrence and vast quantity of natural gas stored is one of the main reasons for such interest in its study and exploration. Gas hydrates are solid crystalline substances with trapped molecules of gas inside cage-like crystals of water molecules. Gases such as methane, ethane, propane and carbon dioxide can form hydrates but in natural state, methane hydrates are the most common. Subsurface geological conditions with high pressure and low temperature favor the formation and stability of gas hydrates. While the occurrence and potential of gas hydrates as energy source has long been studied, there are still gaps in knowledge, especially in the quantitative research of gas hydrate formation and reservoir characterization. This study is focused on exploring and understanding the geological setting in which gas hydrates are formed and the subsequent changes in rock characteristics as they are deposited. It involves the numerical simulation of methane gas flow through fault to form hydrates. The models are representative of the subsurface geologic setting of Gulf of Mexico with a fault through layers of shale and sandstone. Hydrate formation simulated is of thermogenic origin. The simulations are conducted using TOUGH+HYDRATE, a numerical code developed at the Lawrence Berkley National Laboratory for modeling multiphase flow through porous medium. Simulation results predict that as the gas hydrates form in the pores of the model, the porosity, permeability and other rock properties are altered. Preliminary simulation results have shown that hydrates begin to form in the fault zone and gradually in the sandstone layers. The increase in hydrate saturation is followed by decrease in the porosity and permeability of the reservoir rock. Sensitivities on flow rates of gas and water are simulated, using different reservoir properties, fault angles and grid sizes to study the properties of hydrate formation and accumulation in the subsurface.

High pressure-elevated temperature x-ray micro-computed tomography for subsurface applications.

PubMed

Iglauer, Stefan; Lebedev, Maxim

2018-06-01

Physical, chemical and mechanical pore-scale (i.e. micrometer-scale) mechanisms in rock are of key importance in many, if not all, subsurface processes. These processes are highly relevant in various applications, e.g. hydrocarbon recovery, CO 2 geo-sequestration, geophysical exploration, water production, geothermal energy production, or the prediction of the location of valuable hydrothermal deposits. Typical examples are multi-phase flow (e.g. oil and water) displacements driven by buoyancy, viscous or capillary forces, mineral-fluid interactions (e.g. mineral dissolution and/or precipitation over geological times), geo-mechanical rock behaviour (e.g. rock compaction during diagenesis) or fines migration during water production, which can dramatically reduce reservoir permeability (and thus reservoir performance). All above examples are 3D processes, and 2D experiments (as traditionally done for micro-scale investigations) will thus only provide qualitative information; for instance the percolation threshold is much lower in 3D than in 2D. However, with the advent of x-ray micro-computed tomography (μCT) - which is now routinely used - this limitation has been overcome, and such pore-scale processes can be observed in 3D at micrometer-scale. A serious complication is, however, the fact that in the subsurface high pressures and elevated temperatures (HPET) prevail, due to the hydrostatic and geothermal gradients imposed upon it. Such HPET-reservoir conditions significantly change the above mentioned physical and chemical processes, e.g. gas density is much higher at high pressure, which strongly affects buoyancy and wettability and thus gas distributions in the subsurface; or chemical reactions are significantly accelerated at increased temperature, strongly affecting fluid-rock interactions and thus diagenesis and deposition of valuable minerals. It is thus necessary to apply HPET conditions to the aforementioned μCT experiments, to be able to mimic subsurface conditions in a realistic way, and thus to obtain reliable results, which are vital input parameters required for building accurate larger-scale reservoir models which can predict the overall reservoir-scale (hectometer-scale) processes (e.g. oil production or diagenesis of a formation). We thus describe here the basic workflow of such HPET-μCT experiments, equipment requirements and apparatus design; and review the literature where such HPET-μCT experiments were used and which phenomena were investigated (these include: CO 2 geo-sequestration, oil recovery, gas hydrate formation, hydrothermal deposition/reactive flow). One aim of this paper is to give a guideline to users how to set-up a HPET-μCT experiment, and to provide a quick overview in terms of what is possible and what not, at least up to date. As a conclusion, HPET-μCT is a valuable tool when it comes to the investigation of subsurface micrometer-scaled processes, and we expect a rapidly expanding usage of HPET-μCT in subsurface engineering and the subsurface sciences. Copyright © 2018 Elsevier B.V. All rights reserved.

Lithologic Controls on Critical Zone Processes in a Variably Metamorphosed Shale-Hosted Watershed

NASA Astrophysics Data System (ADS)

Eldam Pommer, R.; Navarre-Sitchler, A.

2017-12-01

Local and regional shifts in thermal maturity within sedimentary shale systems impart significant variation in chemical and physical rock properties, such as pore-network morphology, mineralogy, organic carbon content, and solute release potential. Even slight variations in these properties on a watershed scale can strongly impact surface and shallow subsurface processes that drive soil formation, landscape evolution, and bioavailability of nutrients. Our ability to map and quantify the effects of this heterogeneity on critical zone processes is hindered by the complex coupling of the multi-scale nature of rock properties, geochemical signatures, and hydrological processes. This study addresses each of these complexities by synthesizing chemical and physical characteristics of variably metamorphosed shales in order to link rock heterogeneity with modern earth surface and shallow subsurface processes. More than 80 samples of variably metamorphosed Mancos Shale were collected in the East River Valley, Colorado, a headwater catchment of the Upper Colorado River Basin. Chemical and physical analyses of the samples show that metamorphism decreases overall rock porosity, pore anisotropy, and surface area, and introduces unique chemical signatures. All of these changes result in lower overall solute release from the Mancos Shale in laboratory dissolution experiments and a change in rock-derived solute chemistry with decreasing organic carbon and cation exchange capacity (Ca, Na, Mg, and K). The increase in rock competency and decrease in reactivity of the more thermally mature shales appear to subsequently control river morphology, with lower channel sinuosity associated with areas of the catchment underlain by metamorphosed Mancos Shale. This work illustrates the formative role of the geologic template on critical zone processes and landscape development within and across watersheds.

Geo-material surface modification of microchips using layer-by-layer (LbL) assembly for subsurface energy and environmental applications.

PubMed

Zhang, Y Q; Sanati-Nezhad, A; Hejazi, S H

2018-01-16

A key constraint in the application of microfluidic technology to subsurface flow and transport processes is the surface discrepancy between microchips and the actual rocks/soils. This research employs a novel layer-by-layer (LbL) assembly technology to produce rock-forming mineral coatings on microchip surfaces. The outcome of the work is a series of 'surface-mimetic micro-reservoirs (SMMR)' that represent multi-scales and multi-types of natural rocks/soils. For demonstration, the clay pores of sandstones and mudrocks are reconstructed by representatively coating montmorillonite and kaolinite in polydimethylsiloxane (PDMS) microchips in a wide range of channel sizes (width of 10-250 μm, depth of 40-100 μm) and on glass substrates. The morphological and structural properties of mineral coatings are characterized using a scanning electron microscope (SEM), optical microscope and profilometer. The coating stability is tested by dynamic flooding experiments. The surface wettability is characterized by measuring mineral oil-water contact angles. The results demonstrate the formation of nano- to micro-scale, fully-covered and stable mineral surfaces with varying wetting properties. There is an opportunity to use this work in the development of microfluidic technology-based applications for subsurface energy and environmental research.

Geo-material microfluidics at reservoir conditions for subsurface energy resource applications

DOE PAGES

Porter, Mark L.; Jiménez-Martínez, Joaquín; Martinez, Ricardo Martin; ...

2015-08-20

Microfluidic investigations of flow and transport in porous and fractured media have the potential to play a significant role in the development of future subsurface energy resource technologies. However, the majority of experimental systems to date are limited in applicability due to operating conditions and/or the use of engineered material micromodels. In this paper, we have developed a high pressure and temperature microfluidic experimental system that allows for direct observations of flow and transport within geo-material micromodels (e.g. rock, cement) at reservoir conditions. In this manuscript, we describe the experimental system, including our novel micromodel fabrication method that works inmore » both geo- and engineered materials and utilizes 3-D tomography images of real fractures as micromodel templates to better represent the pore space and fracture geometries expected in subsurface formations. We present experimental results that highlight the advantages of using real-rock micromodels and discuss potential areas of research that could benefit from geo-material microfluidic investigations. Finally, the experiments include fracture–matrix interaction in which water imbibes into the shale rock matrix from etched fractures, supercritical CO 2 (scCO 2) displacing brine in idealized and realistic fracture patterns, and three-phase flow involving scCO 2–brine–oil.« less

Reservoir and Source Rock Identification Based on Geologycal, Geophysics and Petrophysics Analysis Study Case: South Sumatra Basin

NASA Astrophysics Data System (ADS)

Anggit Maulana, Hiska; Haris, Abdul

2018-05-01

Reservoir and source rock Identification has been performed to deliniate the reservoir distribution of Talangakar Formation South Sumatra Basin. This study is based on integrated geophysical, geological and petrophysical data. The aims of study to determine the characteristics of the reservoir and source rock, to differentiate reservoir and source rock in same Talangakar formation, to find out the distribution of net pay reservoir and source rock layers. The method of geophysical included seismic data interpretation using time and depth structures map, post-stack inversion, interval velocity, geological interpretations included the analysis of structures and faults, and petrophysical processing is interpret data log wells that penetrating Talangakar formation containing hydrocarbons (oil and gas). Based on seismic interpretation perform subsurface mapping on Layer A and Layer I to determine the development of structures in the Regional Research. Based on the geological interpretation, trapping in the form of regional research is anticline structure on southwest-northeast trending and bounded by normal faults on the southwest-southeast regional research structure. Based on petrophysical analysis, the main reservoir in the field of research, is a layer 1,375 m of depth and a thickness 2 to 8.3 meters.

Quantification of mine-drainage inflows to Little Cottonwood Creek, Utah, using a tracer-injection and synoptic-sampling study

USGS Publications Warehouse

Kimball, B.; Runkel, R.; Gerner, L.

2001-01-01

Historic mining in Little Cottonwood Canyon in Utah has left behind many mine drainage tunnels that discharge water to Little Cottonwood Creek. To quantify the major sources of mine drainage to the stream, synoptic sampling was conducted during a tracer injection under low flow conditions (September 1998). There were distinct increases in discharge downstream from mine drainage and major tributary inflows that represented the total surface and subsurface contributions. The chemistry of stream water determined from synoptic sampling was controlled by the weathering of carbonate rocks and mine drainage inflows. Buffering by carbonate rocks maintained a high pH throughout the study reach. Most of the metal loading was from four surface-water inflows and three subsurface inflows. The main subsurface inflow was from a mine pool in the Wasatch Tunnel. Natural attenuation of all the metals resulted in the formation of colloidal solids, sorption of some metals, and accumulation onto the streambed. The deposition on the streambed could contribute to chronic toxicity for aquatic organisms. Information from the study will help to make decisions about environmental restoration.

Preliminary source rock evaluation and hydrocarbon generation potential of the early Cretaceous subsurface shales from Shabwah sub-basin in the Sabatayn Basin, Western Yemen

NASA Astrophysics Data System (ADS)

Al-Matary, Adel M.; Hakimi, Mohammed Hail; Al Sofi, Sadam; Al-Nehmi, Yousif A.; Al-haj, Mohammed Ail; Al-Hmdani, Yousif A.; Al-Sarhi, Ahmed A.

2018-06-01

A conventional organic geochemical study has been performed on the shale samples collected from the early Cretaceous Saar Formation from the Shabwah oilfields in the Sabatayn Basin, Western Yemen. The results of this study were used to preliminary evaluate the potential source-rock of the shales in the Saar Formation. Organic matter richness, type, and petroleum generation potential of the analysed shales were assessed. Total organic carbon content and Rock- Eval pyrolysis results indicate that the shale intervals within the early Cretaceous Saar Formation have a wide variation in source rock generative potential and quality. The analysed shale samples have TOC content in the range of 0.50 and 5.12 wt% and generally can be considered as fair to good source rocks. The geochemical results of this study also indicate that the analysed shales in the Saar Formation are both oil- and gas-prone source rocks, containing Type II kerogen and mixed Types II-III gradient to Type III kerogen. This is consistent with Hydrogen Index (HI) values between 66 and 552 mg HC/g TOC. The temperature-sensitive parameters such as vitrinite reflectance (%VRo), Rock-Eval pyrolysis Tmax and PI reveal that the analysed shale samples are generally immature to early-mature for oil-window. Therefore, the organic matter has not been altered by thermal maturity thus petroleum has not yet generated. Therefore, exploration strategies should focus on the known deeper location of the Saar Formation in the Shabwah-sub-basin for predicting the kitchen area.

Spreadsheet log analysis in subsurface geology

USGS Publications Warehouse

Doveton, J.H.

2000-01-01

Most of the direct knowledge of the geology of the subsurface is gained from the examination of core and drill-cuttings recovered from boreholes drilled by the petroleum and water industries. Wireline logs run in these same boreholes generally have been restricted to tasks of lithostratigraphic correlation and thee location of hydrocarbon pay zones. However, the range of petrophysical measurements has expanded markedly in recent years, so that log traces now can be transformed to estimates of rock composition. Increasingly, logs are available in a digital format that can be read easily by a desktop computer and processed by simple spreadsheet software methods. Taken together, these developments offer accessible tools for new insights into subsurface geology that complement the traditional, but limited, sources of core and cutting observations.

Microwave assisted hard rock cutting

DOEpatents

Lindroth, David P.; Morrell, Roger J.; Blair, James R.

1991-01-01

An apparatus for the sequential fracturing and cutting of subsurface volume of hard rock (102) in the strata (101) of a mining environment (100) by subjecting the volume of rock to a beam (25) of microwave energy to fracture the subsurface volume of rock by differential expansion; and , then bringing the cutting edge (52) of a piece of conventional mining machinery (50) into contact with the fractured rock (102).

National Uranium Resource Evaluation: Palestine Quadrangle, Texas and Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGowen, M.; Basciano, J.; Fose, F.G. Jr.

1982-09-01

The uranium resource potential of the Palestine Quadrangle, Texas and Louisiana, was evaluated to a depth of 1500 m (5000 ft) using criteria established for the National Uranium Resource Evaluation program. Data derived from geochemical analyses of surface samples (substrate, soil, and stream sediment) in conjunction with hydrochemical data from water wells were used to evaluate geologic environments as being favorable or unfavorable for the occurrence of uranium deposits. Two favorable environments have been identified in the Palestine Quadrangle: potential deposits of modified Texas roll-type in fluvial channels and associated facies within the Yegua Formation, and potential occurrences along mineralizationmore » fronts associated with the Elkhart Graben and Mount Enterprise fault system. Unfavorable environments include: Cretaceous shales and limestones, Tertiary fine-grained marine sequences, Tertiary sandstone units that exhibit favorable host-rock characteristics but fail to show significant syngenetic or epigenetic mineralization, and Quaternary sands and gravels. Unevaluated units include the Woodbine Group (Upper Cretaceous), Jackson Group (Tertiary), and Catahoula Formation (Tertiary). The subsurface interval of the Jackson Group and Catahoula Formation contains depositional facies that may represent favorable environments; however, the evaluation of these units is inconclusive because of the general lack of shallow subsurface control and core material. The Woodbine Group, restricted to the subsurface except for a small exposure over Palestine Dome, occurs above 1500 m (5000 ft) in the northwest quarter of the quadrangle. The unit exhibits favorable host-rock characteristics, but the paucity of gamma logs and cores, as well as the lack of hydrogeochemical and stream-sediment reconnaissance data, makes evaluation of the unit difficult.« less

Exploring for oil with nuclear physics

NASA Astrophysics Data System (ADS)

Mauborgne, Marie-Laure; Allioli, Françoise; Stoller, Chris; Evans, Mike; Manclossi, Mauro; Nicoletti, Luisa

2017-09-01

Oil↓eld service companies help identify and assess reserves and future production for oil and gas reservoirs, by providing petrophysical information on rock formations. Some parameters of interest are the fraction of pore space in the rock, the quantity of oil or gas contained in the pores, the lithology or composition of the rock matrix, and the ease with which 'uids 'ow through the rock, i.e. its permeability. Downhole logging tools acquire various measurements based on electromagnetic, acoustic, magnetic resonance and nuclear physics to determine properties of the subsurface formation surrounding the wellbore. This introduction to nuclear measurements applied in the oil and gas industry reviews the most advanced nuclear measurements currently in use, including capture and inelastic gamma ray spectroscopy, neutron-gamma density, thermal neutron capture cross section, natural gamma ray, gamma-gamma density, and neutron porosity. A brief description of the technical challenges associated with deploying nuclear technology in the extreme environmental conditions of an oil well is also presented.

Reconstructing a hydrogen-driven microbial metabolic network in Opalinus Clay rock.

PubMed

Bagnoud, Alexandre; Chourey, Karuna; Hettich, Robert L; de Bruijn, Ino; Andersson, Anders F; Leupin, Olivier X; Schwyn, Bernhard; Bernier-Latmani, Rizlan

2016-10-14

The Opalinus Clay formation will host geological nuclear waste repositories in Switzerland. It is expected that gas pressure will build-up due to hydrogen production from steel corrosion, jeopardizing the integrity of the engineered barriers. In an in situ experiment located in the Mont Terri Underground Rock Laboratory, we demonstrate that hydrogen is consumed by microorganisms, fuelling a microbial community. Metagenomic binning and metaproteomic analysis of this deep subsurface community reveals a carbon cycle driven by autotrophic hydrogen oxidizers belonging to novel genera. Necromass is then processed by fermenters, followed by complete oxidation to carbon dioxide by heterotrophic sulfate-reducing bacteria, which closes the cycle. This microbial metabolic web can be integrated in the design of geological repositories to reduce pressure build-up. This study shows that Opalinus Clay harbours the potential for chemolithoautotrophic-based system, and provides a model of microbial carbon cycle in deep subsurface environments where hydrogen and sulfate are present.

Reconstructing a hydrogen-driven microbial metabolic network in Opalinus Clay rock

PubMed Central

Bagnoud, Alexandre; Chourey, Karuna; Hettich, Robert L.; de Bruijn, Ino; Andersson, Anders F.; Leupin, Olivier X.; Schwyn, Bernhard; Bernier-Latmani, Rizlan

2016-01-01

The Opalinus Clay formation will host geological nuclear waste repositories in Switzerland. It is expected that gas pressure will build-up due to hydrogen production from steel corrosion, jeopardizing the integrity of the engineered barriers. In an in situ experiment located in the Mont Terri Underground Rock Laboratory, we demonstrate that hydrogen is consumed by microorganisms, fuelling a microbial community. Metagenomic binning and metaproteomic analysis of this deep subsurface community reveals a carbon cycle driven by autotrophic hydrogen oxidizers belonging to novel genera. Necromass is then processed by fermenters, followed by complete oxidation to carbon dioxide by heterotrophic sulfate-reducing bacteria, which closes the cycle. This microbial metabolic web can be integrated in the design of geological repositories to reduce pressure build-up. This study shows that Opalinus Clay harbours the potential for chemolithoautotrophic-based system, and provides a model of microbial carbon cycle in deep subsurface environments where hydrogen and sulfate are present. PMID:27739431

CO2-Water-Rock Wettability: Variability, Influencing Factors, and Implications for CO2 Geostorage.

PubMed

Iglauer, Stefan

2017-05-16

Carbon geosequestration (CGS) has been identified as a key technology to reduce anthropogenic greenhouse gas emissions and thus significantly mitigate climate change. In CGS, CO 2 is captured from large point-source emitters (e.g., coal fired power stations), purified, and injected deep underground into geological formations for disposal. However, the CO 2 has a lower density than the resident formation brine and thus migrates upward due to buoyancy forces. To prevent the CO 2 from leaking back to the surface, four trapping mechanisms are used: (1) structural trapping (where a tight caprock acts as a seal barrier through which the CO 2 cannot percolate), (2) residual trapping (where the CO 2 plume is split into many micrometer-sized bubbles, which are immobilized by capillary forces in the pore network of the rock), (3) dissolution trapping (where CO 2 dissolves in the formation brine and sinks deep into the reservoir due to a slight increase in brine density), and (4) mineral trapping (where the CO 2 introduced into the subsurface chemically reacts with the formation brine or reservoir rock or both to form solid precipitates). The efficiency of these trapping mechanisms and the movement of CO 2 through the rock are strongly influenced by the CO 2 -brine-rock wettability (mainly due to the small capillary-like pores in the rock which form a complex network), and it is thus of key importance to rigorously understand CO 2 -wettability. In this context, a substantial number of experiments have been conducted from which several conclusions can be drawn: of prime importance is the rock surface chemistry, and hydrophilic surfaces are water-wet while hydrophobic surfaces are CO 2 -wet. Note that CO 2 -wet surfaces dramatically reduce CO 2 storage capacities. Furthermore, increasing pressure, salinity, or dissolved ion valency increases CO 2 -wettability, while the effect of temperature is not well understood. Indeed theoretical understanding of CO 2 -wettability and the ability to quantitatively predict it are currently limited although recent advances have been made. Moreover, data for real storage rock and real injection gas (which contains impurities) is scarce and it is an open question how realistic subsurface conditions can be reproduced in laboratory experiments. In conclusion, however, it is clear that in principal CO 2 -wettability can vary drastically from completely water-wet to almost completely CO 2 -wet, and this possible variation introduces a large uncertainty into trapping capacity and containment security predictions.

Studying physical properties of deformed intact and fractured rocks by micro-scale hydro-mechanical-seismicity model

NASA Astrophysics Data System (ADS)

Raziperchikolaee, Samin

The pore pressure variation in an underground formation during hydraulic stimulation of low permeability formations or CO2 sequestration into saline aquifers can induce microseismicity due to fracture generation or pre-existing fracture activation. While the analysis of microseismic data mainly focuses on mapping the location of fractures, the seismic waves generated by the microseismic events also contain information for understanding of fracture mechanisms based on microseismic source analysis. We developed a micro-scale geomechanics, fluid-flow and seismic model that can predict transport and seismic source behavior during rock failure. This model features the incorporation of microseismic source analysis in fractured and intact rock transport properties during possible rock damage and failure. The modeling method considers comprehensive grains and cements interaction through a bonded-particle-model. As a result of grain deformation and microcrack development in the rock sample, forces and displacements in the grains involved in the bond breakage are measured to determine seismic moment tensor. In addition, geometric description of the complex pore structure is regenerated to predict fluid flow behavior of fractured samples. Numerical experiments are conducted for different intact and fractured digital rock samples, representing various mechanical behaviors of rocks and fracture surface properties, to consider their roles on seismic and transport properties of rocks during deformation. Studying rock deformation in detail provides an opportunity to understand the relationship between source mechanism of microseismic events and transport properties of damaged rocks to have a better characterizing of fluid flow behavior in subsurface formations.

Uranium favorability of the San Rafael Swell area, east-central Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickle, D G; Jones, C A; Gallagher, G L

1977-10-01

The San Rafael Swell project area in east-central Utah is approximately 3,000 sq mi and includes the San Rafael Swell anticline and the northern part of the Waterpocket Fold monocline at Capitol Reef. Rocks in the area are predominantly sedimentary rocks of Pennsylvanian through Cretaceous age. Important deposits of uranium in the project area are restricted to two formations, the Chinle (Triassic) and Morrison (Jurassic) Formations. A third formation, the White Rim Sandstone (Permian), was also studied because of reported exploration activity. The White Rim Sandstone is considered generally unfavorable on the basis of lithologic characteristics, distance from a possiblemore » source of uranium, lack of apparent mineralization, and the scarcity of anomalies on gamma-ray logs or in rock, water, and stream-sediment samples. The lower Chinle from the Moss Back Member down to the base of the formation is favorable because it is a known producer. New areas for exploration are all subsurface. Both Salt Wash and Brushy Basin Members of the Morrison Formation are favorable. The Salt Wash Member is favorable because it is a known producer. The Brushy Basin Member is favorable as a low-grade resource.« less

Real rock-microfluidic flow cell: A test bed for real-time in situ analysis of flow, transport, and reaction in a subsurface reactive transport environment.

PubMed

Singh, Rajveer; Sivaguru, Mayandi; Fried, Glenn A; Fouke, Bruce W; Sanford, Robert A; Carrera, Martin; Werth, Charles J

2017-09-01

Physical, chemical, and biological interactions between groundwater and sedimentary rock directly control the fundamental subsurface properties such as porosity, permeability, and flow. This is true for a variety of subsurface scenarios, ranging from shallow groundwater aquifers to deeply buried hydrocarbon reservoirs. Microfluidic flow cells are now commonly being used to study these processes at the pore scale in simplified pore structures meant to mimic subsurface reservoirs. However, these micromodels are typically fabricated from glass, silicon, or polydimethylsiloxane (PDMS), and are therefore incapable of replicating the geochemical reactivity and complex three-dimensional pore networks present in subsurface lithologies. To address these limitations, we developed a new microfluidic experimental test bed, herein called the Real Rock-Microfluidic Flow Cell (RR-MFC). A porous 500μm-thick real rock sample of the Clair Group sandstone from a subsurface hydrocarbon reservoir of the North Sea was prepared and mounted inside a PDMS microfluidic channel, creating a dynamic flow-through experimental platform for real-time tracking of subsurface reactive transport. Transmitted and reflected microscopy, cathodoluminescence microscopy, Raman spectroscopy, and confocal laser microscopy techniques were used to (1) determine the mineralogy, geochemistry, and pore networks within the sandstone inserted in the RR-MFC, (2) analyze non-reactive tracer breakthrough in two- and (depth-limited) three-dimensions, and (3) characterize multiphase flow. The RR-MFC is the first microfluidic experimental platform that allows direct visualization of flow and transport in the pore space of a real subsurface reservoir rock sample, and holds potential to advance our understandings of reactive transport and other subsurface processes relevant to pollutant transport and cleanup in groundwater, as well as energy recovery. Copyright © 2017 Elsevier B.V. All rights reserved.

National Uranium Resource Evaluation: Aztec quadrangle, New Mexico and Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, M.W.

1982-09-01

Areas and formations within the Aztec 1/sup 0/ x 2/sup 0/ Quadrangle, New Mexico and Colorado considered favorable for uranium endowment of specified minimum grade and tonnage include, in decreasing order of favorability: (1) the Early Cretaceous Burro Canyon Formation in the southeastern part of the Chama Basin; (2) the Tertiary Ojo Alamo Sandstone in the east-central part of the San Juan Basin; and (3) the Jurassic Westwater Canyon and Brushy Basin Members of the Morrison Formation in the southwestern part of the quadrangle. Favorability of the Burro Canyon is based on the presence of favorable host-rock facies, carbonaceous materialmore » and pyrite to act as a reductant for uranium, and the presence of mineralized ground in the subsurface of the Chama Basin. The Ojo Alamo Sandstone is considered favorable because of favorable host-rock facies, the presence of carbonaceous material and pyrite to act as a reductant for uranium, and the presence of a relatively large subsurface area in which low-grade mineralization has been encountered in exploration activity. The Morrison Formation, located within the San Juan Basin adjacent to the northern edge of the Grants mineral belt, is considered favorable because of mineralization in several drill holes at depths near 1500 m (5000 ft) and because of favorable facies relationships extending into the Aztec Quadrangle from the Grants mineral belt which lies in the adjacent Albuquerque and Gallup Quadrangles. Formations considered unfavorable for uranium deposits of specified tonnage and grade include the remainder of sedimentary and igneous formations ranging from Precambrian to Quaternary in age. Included under the unfavorable category are the Cutler Formation of Permian age, and Dakota Sandstone of Late Cretaceous age, and the Nacimiento and San Jose Formations of Tertiary age.« less

Tectonosedimentary framework of Upper Cretaceous -Neogene series in the Gulf of Tunis inferred from subsurface data: implications for petroleum exploration

NASA Astrophysics Data System (ADS)

Dhraief, Wissem; Dhahri, Ferid; Chalwati, Imen; Boukadi, Noureddine

2017-04-01

The objective and the main contribution of this issue are dedicated to using subsurface data to delineate a basin beneath the Gulf of Tunis and its neighbouring areas, and to investigate the potential of this area in terms of hydrocarbon resources. Available well data provided information about the subsurface geology beneath the Gulf of Tunis. 2D seismic data allowed delineation of the basin shape, strata geometries, and some potential promising subsurface structures in terms of hydrocarbon accumulation. Together with lithostratigraphic data obtained from drilled wells, seismic data permitted the construction of isochron and isobath maps of Upper Cretaceous-Neogene strata. Structural and lithostratigraphic interpretations indicate that the area is tectonically complex, and they highlight the tectonic control of strata deposition during the Cretaceous and Neogene. Tectonic activity related to the geodynamic evolution of the northern African margin appears to have been responsible for several thickness and facies variations, and to have played a significant role in the establishment and evolution of petroleum systems in northeastern Tunisia. As for petroleum systems in the basin, the Cretaceous series of the Bahloul, Mouelha and Fahdene formations are acknowledged to be the main source rocks. In addition, potential reservoirs (Fractured Abiod and Bou Dabbous carbonated formations) sealed by shaly and marly formations (Haria and Souar formations respectively) show favourable geometries of trap structures (anticlines, tilted blocks, unconformities, etc.) which make this area adequate for hydrocarbon accumulations.

Mineral storage of CO2/H2S gas mixture injection in basaltic rocks

NASA Astrophysics Data System (ADS)

Clark, D. E.; Gunnarsson, I.; Aradottir, E. S.; Oelkers, E. H.; Sigfússon, B.; Snæbjörnsdottír, S. Ó.; Matter, J. M.; Stute, M.; Júlíusson, B. M.; Gíslason, S. R.

2017-12-01

Carbon capture and storage is one solution to reducing CO2 emissions in the atmosphere. The long-term geological storage of buoyant supercritical CO2 requires high integrity cap rock. Some of the risk associated with CO2 buoyancy can be overcome by dissolving CO2 into water during its injection, thus eliminating its buoyancy. This enables injection into fractured rocks, such as basaltic rocks along oceanic ridges and on continents. Basaltic rocks are rich in divalent cations, Ca2+, Mg2+ and Fe2+, which react with CO2 dissolved in water to form stable carbonate minerals. This possibility has been successfully tested as a part of the CarbFix CO2storage pilot project at the Hellisheiði geothermal power plant in Iceland, where they have shown mineralization occurs in less than two years [1, 2]. Reykjavik Energy and the CarbFix group has been injecting a mixture of CO2 and H2S at 750 m depth and 240-250°C since June 2014; by 1 January 2016, 6290 tons of CO2 and 3530 tons of H2S had been injected. Once in the geothermal reservoir, the heat exchange and sufficient dissolution of the host rock neutralizes the gas-charged water and saturates the formation water respecting carbonate and sulfur minerals. A thermally stable inert tracer was also mixed into the stream to monitor the subsurface transport and to assess the degree of subsurface carbonation and sulfide precipitation [3]. Water and gas samples have been continuously collected from three monitoring wells and geochemically analyzed. Based on the results, mineral saturation stages have been defined. These results and tracer mass balance calculations are used to evaluate the rate and magnitude of CO2 and H2S mineralization in the subsurface, with indications that mineralization of carbon and sulfur occurs within months. [1] Gunnsarsson, I., et al. (2017). Rapid and cost-effective capture and subsurface mineral storage of carbon and sulfur. Manuscript submitted for publication. [2] Matter, J., et al. (2016). Rapid carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions. Science 352 (6291), 1312-1314. [3] Snæbjörnsdottír, S.O., et al. (2017). The chemistry and saturation states of subsurface fluids during the in-situ mineralisation of CO2 and H2S at the CarbFix site in SW-Iceland. International Journal of Greenhouse Gas Control 58, 87-102.

Aquifer Characterization and Groundwater Potential Evaluation in Sedimentary Rock Formation

NASA Astrophysics Data System (ADS)

Ashraf, M. A. M.; Yusoh, R.; Sazalil, M. A.; Abidin, M. H. Z.

2018-04-01

This study was conducted to characterize the aquifer and evaluate the ground water potential in the formation of sedimentary rocks. Electrical resistivity and drilling methods were used to develop subsurface soil profile for determining suitable location for tube well construction. The electrical resistivity method was used to infer the subsurface soil layer by use of three types of arrays, namely, the pole–dipole, Wenner, and Schlumberger arrays. The surveys were conducted using ABEM Terrameter LS System, and the results were analyzed using 2D resistivity inversion program (RES2DINV) software. The survey alignments were performed with maximum electrode spreads of 400 and 800 m by employing two different resistivity survey lines at the targeted zone. The images were presented in the form of 2D resistivity profiles to provide a clear view of the distribution of interbedded sandstone, siltstone, and shale as well as the potential groundwater zones. The potential groundwater zones identified from the resistivity results were confirmed using pumping, step drawdown, and recovery tests. The combination among the three arrays and the correlation between the well log and pumping test are reliable and successful in identifying potential favorable zones for obtaining groundwater in the study area.

Serpentinization and Synthesis: Can abiotic and biotic non-volatile organic molecules be identified in the subsurface of the Atlantis Massif?

NASA Astrophysics Data System (ADS)

Hickok, K.; Nguyen, T.; Orcutt, B.; Fruh-Green, G. L.; Wanamaker, E.; Lang, S. Q.

2016-12-01

The high concentrations of hydrogen created during serpentinization can promote the formation of abiotic organic carbon molecules such as methane, formate, short chain hydrocarbons and, in laboratory experiments, larger molecules containing up to 32 carbon atoms. Subsurface archaeal and bacterial communities can use these reduced compounds for metabolic energy. International Ocean Discovery Project Expedition 357 drilled into the Atlantis Massif with the goals of investigating carbon cycling and the presence of life in a zone of active serpentinization. The expedition recovered multiple rock lithologies including gabbros, basalts, carbonate sands, and serpentinites. A subset of these samples are being analyzed to determine if non-volatile organic molecules are produced abiotically in serpentinizing environments and to identify `hot spots' of microbial life in the subsurface. Rock samples of contrasting representative lithologies are being analyzed for the presence of n-alkanes and fatty acids. Preliminary results have so far indicated the presence of alkanes in some samples. The isotopic (13C, 2H) characteristics of these compounds are being compared to a suite of oils, greases, and drilling fluids used during sample collection to distinguish in situ abiotic and biotic signatures from contaminant compounds. Other initial results have shown the efficacy of various sample-handling procedures designed to reduce surface contamination. This study will contribute to the overall understanding of the role serpentinization plays in the global carbon cycle and its implications for pre-biotic chemistry.

Continuity of Permian Mengkareng formation through GPR interpretation in Merangin Geopark

NASA Astrophysics Data System (ADS)

Hanif, F.; Syahputra, R.; Kristyanto, T. H. W.; Tempessy, A. S.; Rokhmatuloh

2017-07-01

The Permian Mengkarang Formation was a part of the continental margin (Gondwana Land) which separated in the Devon Period. In this period, Gondwana Land experienced glaciation at the Paleo South Pole. However, the fossils found in Mengkarang Formation were tropical flora, had made the Merangin to be certified as one of the national geoparks. It also shows that the geological process (stratigraphy and tectonic) in the Merangin has occurred before the Indonesian archipelago was formed: namely the Permian to Triassic period. Ground Penetrating Radar (GPR) was chosen as an effective geophysical method to study shallow subsurface geology. GPR and seismic reflection method have the same common principle to identify the facies and sub-sequence stratigraphy but they are different in implementation. Therefore, this study aims to deliver the vertical continuity of the Permian Mengkarang Formation in high resolution unit. The GPR result showing the subsurface image is based on dielectric of the rock layers. The GPR sections show the absence of the unconformity delivered in the intercalation between mudstone, sandstone, and tuff. Thus, it can be concluded that the Permian Mengkareng Formation continues up to 20 m depth.

Paleozoic sedimentary rocks in the Red Dog Zn-Pb-Ag district and vicinity, western Brooks Range, Alaska: provenance, deposition, and metallogenic significance

USGS Publications Warehouse

Slack, John F.; Dumoulin, Julie A.; Schmidt, J.M.; Young, L.E.; Rombach, Cameron

2004-01-01

The distribution and composition of Paleozoic strata in the western Brooks Range may have played a fundamental role in Zn-Pb mineralization of the Red Dog district. In our model, deposition and early lithification of biogenic chert and bedded siliceous rocks in the upper part of the Kuna Formation served as a regional hydrologic seal, acting as a cap rock to heat and hydrothermal fluids during Late Mississippian base-metal mineralization. Equally important was the iron-poor composition of black shales of the Kuna Formation (i.e., low Fe/Ti ratios), which limited synsedimentary pyrite formation in precursor sediments, resulting in significant H2S production in pore waters through the interaction of aqueous sulfate with abundant organic matter. This H2S may have been critical to the subsurface deposition of the huge quantities of Zn and Pb in the district. On the basis of this model, we propose that low Fe/Ti and S/C ratios in black shale sequences are potential basin-scale exploration guides for giant sediment-hosted, stratiform Zn-Pb-Ag deposits.

Quantitative 3D model of light transmittance through translucent rocks applied to the hypolithic microbial community.

PubMed

Jolitz, Rebecca D; McKay, Christopher P

2013-07-01

In extreme desert environments, photosynthetic microorganisms often live on the buried undersides of translucent rocks. Computing the light level reaching these locations requires 3D modeling of a finite rock. We report on Monte Carlo calculations of skylight and sunlight transmission through a partially buried flat cylindrical rock using one billion photons per simulation. Transmitted light level drops inversely with increasing rock opacity, as expected for purely scattering media. For a half-buried rock with an extinction coefficient of 0.1 cm(-1) (opacity of 0.2), transmission at the bottom is 64 % for sunlight at a solar zenith angle of 60° and 82 % for skylight. Transmitted light level increases slowly with increasing scattering asymmetry factor of the rock independent of illumination or depth buried. Transmitted sunlight at zenith through a thick half-buried rock (opacity of 0.6) is six times brighter at the bottom than the subsurface sides. Skylight transmits equally to the subsurface sides and bottom. When the sun is not straight overhead, the sunward side of the rock is brighter than the underside of the rock. Compared to the sunlight transmitted to the bottom, transmitted sunlight inclined at 60° is 24 times brighter at the subsurface side towards the sun and 14 times brighter at the subsurface side 70° away from the sun. Transmitted sunlight emitted from zenith and skylight is uniformly bright at the bottom regardless of how deeply the rock is buried. Sunlight not at zenith transmits preferentially to the sunward bottom edge depending on the depth the rock is buried.

System and method for investigating sub-surface features of a rock formation with acoustic sources generating coded signals

DOEpatents

Vu, Cung Khac; Nihei, Kurt; Johnson, Paul A; Guyer, Robert; Ten Cate, James A; Le Bas, Pierre-Yves; Larmat, Carene S

2014-12-30

A system and a method for investigating rock formations includes generating, by a first acoustic source, a first acoustic signal comprising a first plurality of pulses, each pulse including a first modulated signal at a central frequency; and generating, by a second acoustic source, a second acoustic signal comprising a second plurality of pulses. A receiver arranged within the borehole receives a detected signal including a signal being generated by a non-linear mixing process from the first-and-second acoustic signal in a non-linear mixing zone within the intersection volume. The method also includes-processing the received signal to extract the signal generated by the non-linear mixing process over noise or over signals generated by a linear interaction process, or both.

System and method for investigating sub-surface features of a rock formation with acoustic sources generating conical broadcast signals

DOEpatents

Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

2015-08-18

A method of interrogating a formation includes generating a conical acoustic signal, at a first frequency--a second conical acoustic signal at a second frequency each in the between approximately 500 Hz and 500 kHz such that the signals intersect in a desired intersection volume outside the borehole. The method further includes receiving, a difference signal returning to the borehole resulting from a non-linear mixing of the signals in a mixing zone within the intersection volume.

Palynostratigraphic correlation of the Fort Union formation (Paleocene) in the Wind River Reservation and Waltman Area, Wind River Basin, Wyoming

USGS Publications Warehouse

Nichols, D.J.; Flores, R.M.

1993-01-01

Palynologic samples of the Fort Union Formation (Paleocene) were collected from selected composite measured sections and a drill hole in the Wind River Basin. Intervals studied are in outcrop in the Wind River Reservation in the Shotgun Butte area and near Hudson, Wyoming, and in the subsurface in the Muddy Ridge field. Age determinations were made using the palynostratigraphic zonation originally developed near Waltman, Wyoming, in the northeastern part of the basin. Although parts of the zonation have been called into question by other recent work in the basin, only the basal Paleocene biozone (P1) is in need of modification, and the zonation remains an effective tool for age determination and correlation in these rocks. Age control is sparse in parts of some sections studied, mostly because of a dominance of sandstone and conglomerate facies, but palynostratigraphy permits correlation of the study areas with each other and with the Waltman reference section.Palynology supports the following correlations: The lower unnamed member of the Fort Union Formation in the Shotgun Butte area correlates stratigraphically and chronologically with the lower part of the formation in the subsurface at Muddy Ridge field, with a short interval in the Hudson area, and with the lower and middle parts of the unnamed member in the Waltman area. The Shotgun Member correlates chronologically with the coal-bearing upper part of the Fort Union Formation in the subsurface at Muddy Ridge field and with the upper part of the unnamed member and Waltman Shale Member in the Waltman area. These correlations show that significant coal deposits in the subsurface have little or no expression in outcrop because of changes in facies.

Application of uniaxial confining-core clamp with hydrous pyrolysis in petrophysical and geochemical studies of source rocks at various thermal maturities

USGS Publications Warehouse

Lewan, Michael D.; Birdwell, Justin E.; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

2013-01-01

Understanding changes in petrophysical and geochemical parameters during source rock thermal maturation is a critical component in evaluating source-rock petroleum accumulations. Natural core data are preferred, but obtaining cores that represent the same facies of a source rock at different thermal maturities is seldom possible. An alternative approach is to induce thermal maturity changes by laboratory pyrolysis on aliquots of a source-rock sample of a given facies of interest. Hydrous pyrolysis is an effective way to induce thermal maturity on source-rock cores and provide expelled oils that are similar in composition to natural crude oils. However, net-volume increases during bitumen and oil generation result in expanded cores due to opening of bedding-plane partings. Although meaningful geochemical measurements on expanded, recovered cores are possible, the utility of the core for measuring petrophysical properties relevant to natural subsurface cores is not suitable. This problem created during hydrous pyrolysis is alleviated by using a stainless steel uniaxial confinement clamp on rock cores cut perpendicular to bedding fabric. The clamp prevents expansion just as overburden does during natural petroleum formation in the subsurface. As a result, intact cores can be recovered at various thermal maturities for the measurement of petrophysical properties as well as for geochemical analyses. This approach has been applied to 1.7-inch diameter cores taken perpendicular to the bedding fabric of a 2.3- to 2.4-inch thick slab of Mahogany oil shale from the Eocene Green River Formation. Cores were subjected to hydrous pyrolysis at 360 °C for 72 h, which represents near maximum oil generation. One core was heated unconfined and the other was heated in the uniaxial confinement clamp. The unconfined core developed open tensile fractures parallel to the bedding fabric that result in a 38 % vertical expansion of the core. These open fractures did not occur in the confined core, but short, discontinuous vertical fractures on the core periphery occurred as a result of lateral expansion.

Composition and structure of the shallow subsurface of Ceres revealed by crater morphology

NASA Astrophysics Data System (ADS)

Bland, Michael T.; Raymond, Carol A.; Schenk, Paul M.; Fu, Roger R.; Kneissl, Thomas; Pasckert, Jan Hendrik; Hiesinger, Harry; Preusker, Frank; Park, Ryan S.; Marchi, Simone; King, Scott D.; Castillo-Rogez, Julie C.; Russell, Christopher T.

2016-07-01

Before NASA’s Dawn mission, the dwarf planet Ceres was widely believed to contain a substantial ice-rich layer below its rocky surface. The existence of such a layer has significant implications for Ceres’s formation, evolution, and astrobiological potential. Ceres is warmer than icy worlds in the outer Solar System and, if its shallow subsurface is ice-rich, large impact craters are expected to be erased by viscous flow on short geologic timescales. Here we use digital terrain models derived from Dawn Framing Camera images to show that most of Ceres’s largest craters are several kilometres deep, and are therefore inconsistent with the existence of an ice-rich subsurface. We further show from numerical simulations that the absence of viscous relaxation over billion-year timescales implies a subsurface viscosity that is at least one thousand times greater than that of pure water ice. We conclude that Ceres’s shallow subsurface is no more than 30% to 40% ice by volume, with a mixture of rock, salts and/or clathrates accounting for the other 60% to 70%. However, several anomalously shallow craters are consistent with limited viscous relaxation and may indicate spatial variations in subsurface ice content.

Composition and structure of the shallow subsurface of Ceres revealed by crater morphology

USGS Publications Warehouse

Bland, Michael T.; Carol A. Raymond,; Schenk, Paul M.; Roger R. Fu,; Thomas Kneisl,; Hendrick Pasckert, Jan; Hiesinger, Harald; Frank Preusker,; Ryan S. Park,; Simone Marchi,; Scott King,; Castillo-Rogez, Julie C.; Christopher T. Russell,

2016-01-01

Before NASA’s Dawn mission, the dwarf planet Ceres was widely believed to contain a substantial ice-rich layer below its rocky surface. The existence of such a layer has significant implications for Ceres’s formation, evolution, and astrobiological potential. Ceres is warmer than icy worlds in the outer Solar System and, if its shallow subsurface is ice-rich, large impact craters are expected to be erased by viscous flow on short geologic timescales. Here we use digital terrain models derived from Dawn Framing Camera images to show that most of Ceres’s largest craters are several kilometres deep, and are therefore inconsistent with the existence of an ice-rich subsurface. We further show from numerical simulations that the absence of viscous relaxation over billion-year timescales implies a subsurface viscosity that is at least one thousand times greater than that of pure water ice. We conclude that Ceres’s shallow subsurface is no more than 30% to 40% ice by volume, with a mixture of rock, salts and/or clathrates accounting for the other 60% to 70%. However, several anomalously shallow craters are consistent with limited viscous relaxation and may indicate spatial variations in subsurface ice content.

Effects of Hydraulic Frac Fluids on Subsurface Microbial Communities in Gas Shales

NASA Astrophysics Data System (ADS)

Jiménez, Núria; Krüger, Martin

2014-05-01

Shale gas is being considered as a complementary energy resource to coal or other fossil fuels. The exploitation of unconventional gas reservoirs requires the use of advanced drilling techniques and hydraulic stimulation (fracking). During fracking operations, large amounts of fluids (fresh water, proppants and chemical additives) are injected at high pressures into the formations, to produce fractures and fissures, and thus to release gas from the source rock into the wellbore. The injected fluids partly remain in the formation, while about 20 to 40% of the originally injected fluid flows back to the surface, together with formation waters, sometimes containing dissolved hydrocarbons, high salt concentrations, etc. The overall production operation will likely affect and be affected by subsurface microbial communities associated to the shale formations. On the one hand microbial activity (like growth, biofilm formation) can cause unwanted processes like corrosion, clogging, etc. On the other hand, the introduction of frac fluids could either enhance microbial growth or cause toxicity to the shale-associated microbial communities. To investigate the potential impacts of changing environmental reservoir conditions, like temperature, salinity, oxgen content and pH, as well as the introduction of frac or geogenic chemicals on subsurface microbial communities, laboratory experiments under in situ conditions (i.e. high temperatures and pressures) are being conducted. Enrichment cultures with samples from several subsurface environments (e.g. shale and coal deposits, gas reservoirs, geothermal fluids) have been set up using a variety of carbon sources, including hydrocarbons and typical frac chemicals. Classical microbiological and molecular analysis are used to determine changes in the microbial abundance, community structure and function after the exposure to different single frac chemicals, "artificial" frac fluids or production waters. On the other hand, potential transformation reactions of frac or geogenic chemicals by subsurface microbiota and their lifetime are investigated. In our "fracking simulation" experiments, an increasing number of hydrocarbon-degrading or halophilic microorganisms is to be expected after exposure of subsurface communities to artificial production waters. Whereas the introduction of freshwater and of easily biodegradable substrates might favor the proliferation of fast-growing generalistic heterotrophs in shale-associated communities. Nevertheless toxicity of some of the frac components cannot be excluded.

Kerogen maturation and incipient graphitization of hydrocarbon source rocks in the Arkoma Basin, Oklahoma and Arkansas: A combined petrographic and Raman spectrometric study

USGS Publications Warehouse

Spotl, C.; Houseknecht, D.W.; Jaques, R.C.

1998-01-01

Dispersed kerogen of the Woodford-Chattanooga and Atoka Formations from the subsurface of the Arkoma Basin show a wide range of thermal maturities (0.38 to 6.1% R(o)) indicating thermal conditions ranging from diagenesis to incipient rock metamorphism. Raman spectral analysis reveals systematic changes of both the first- and second-order spectrum with increasing thermal maturity. These changes include a pronounced increase in the D/O peak height ratio accompanied by a narrowing of the D peak, a gradual decrease in the D/O peak width ratio, and a shift of both peaks toward higher wave numbers. Second-order Raman peaks, though less intensive, also show systematic peak shifting as a function of R(o). These empirical results underscore the high potential of Raman spectrometry as a fast and reliable geothermometer of mature to supermature hydrocarbon source rocks, and as an indicator of thermal maturity levels within the anchizone.Dispersed kerogen of the Woodford-Chattanooga and Atoka Formations from the subsurface of the Arkoma Basin show a wide range of thermal maturities (0.38 to 6.1% Ro) indicating thermal conditions ranging from diagenesis to incipient rock metamorphism. Raman spectral analysis reveals systematic changes of both the first- and second-order spectrum with increasing thermal maturity. These changes include a pronounced increase in the D/O peak height ratio accompanied by a narrowing of the D peak, a gradual decrease in the D/O peak width ratio, and a shift of both peaks toward higher wave numbers. Second-order Raman peaks, though less intensive, also show systematic peak shifting as a function of Ro. These empirical results underscore the high potential of Raman spectrometry as a fast and reliable geothermometer of mature to supermature hydrocarbon source rocks, and as an indicator of thermal maturity levels within the anchizone.

Marine magnetic survey and onshore gravity and magnetic survey, San Pablo Bay, northern California

USGS Publications Warehouse

Ponce, David A.; Denton, Kevin M.; Watt, Janet T.

2016-09-12

IntroductionFrom November 2011 to August 2015, the U.S. Geological Survey (USGS) collected more than 1,000 line-kilometers (length of lines surveyed in kilometers) of marine magnetic data on San Pablo Bay, 98 onshore gravity stations, and over 27 line-kilometers of ground magnetic data in northern California. Combined magnetic and gravity investigations were undertaken to study subsurface geologic structures as an aid in understanding the geologic framework and earthquake hazard potential in the San Francisco Bay Area. Furthermore, marine magnetic data illuminate local subsurface geologic features in the shallow crust beneath San Pablo Bay where geologic exposure is absent.Magnetic and gravity methods, which reflect contrasting physical properties of the subsurface, are ideal for studying San Pablo Bay. Exposed rock units surrounding San Pablo Bay consist mainly of Jurassic Coast Range ophiolite, Great Valley sequence, Franciscan Complex rocks, Miocene sedimentary rocks, and unconsolidated alluvium (Graymer and others, 2006). The contrasting magnetic and density properties of these rocks enable us to map their subsurface extent.

Mineralization of Bacteria in Terrestrial Basaltic Rocks: Comparison With Possible Biogenic Features in Martian Meteorite Allan Hills 84001

NASA Technical Reports Server (NTRS)

Thomas-Keprta, K. L.; McKay, D. S.; Wentworth, S. J.; Stevens, T. O.; Taunton, A. E.; Allen, C. C.; Gibson, E. K., Jr.; Romanek, C. S.

1998-01-01

The identification of biogenic features altered by diagenesis or mineralization is important in determining whether specific features in terrestrial rocks and in meteorites may have a biogenic origin. Unfortunately, few studies have addressed the formation of biogenic features in igneous rocks, which may be important to these phenomena, including the controversy over possible biogenic features in basaltic martian meteorite ALH84001. To explore the presence of biogenic features in igneous rocks, we examined microcosms growing in basaltic small-scale experimental growth chambers or microcosms. Microbial communities were harvested from aquifers of the Columbia River Basalt (CRB) group and grown in a microcosm containing unweathered basalt chips and groundwater (technique described in. These microcosms simulated natural growth conditions in the deep subsurface of the CRB, which should be a good terrestrial analog for any putative martian subsurface ecosystem that may have once included ALH84001. Here we present new size measurements and photomicrographs comparing the putative martian fossils to biogenic material in the CRB microcosms. The range of size and shapes of the biogenic features on the CRB microcosm chips overlaps with and is similar to those on ALH84001 chips. Although this present work does not provide evidence for the biogenicity of ALH84001 features, we believe that, based on criteria of size, shape, and general morphology, a biogenic interpretation for the ALH84001 features remains plausible.

Geophysical technique for mineral exploration and discrimination based on electromagnetic methods and associated systems

DOEpatents

Zhdanov,; Michael, S [Salt Lake City, UT

2008-01-29

Mineral exploration needs a reliable method to distinguish between uneconomic mineral deposits and economic mineralization. A method and system includes a geophysical technique for subsurface material characterization, mineral exploration and mineral discrimination. The technique introduced in this invention detects induced polarization effects in electromagnetic data and uses remote geophysical observations to determine the parameters of an effective conductivity relaxation model using a composite analytical multi-phase model of the rock formations. The conductivity relaxation model and analytical model can be used to determine parameters related by analytical expressions to the physical characteristics of the microstructure of the rocks and minerals. These parameters are ultimately used for the discrimination of different components in underground formations, and in this way provide an ability to distinguish between uneconomic mineral deposits and zones of economic mineralization using geophysical remote sensing technology.

A possible terrestrial analogue for haematite concretions on Mars.

PubMed

Chan, Marjorie A; Beitler, Brenda; Parry, W T; Ormö, Jens; Komatsu, Goro

2004-06-17

Recent exploration has revealed extensive geological evidence for a water-rich past in the shallow subsurface of Mars. Images of in situ and loose accumulations of abundant, haematite-rich spherical balls from the Mars Exploration Rover 'Opportunity' landing site at Meridiani Planum bear a striking resemblance to diagenetic (post-depositional), haematite-cemented concretions found in the Jurassic Navajo Sandstone of southern Utah. Here we compare the spherical concretions imaged on Mars to these terrestrial concretions, and investigate the implications for analogous groundwater-related formation mechanisms. The morphology, character and distribution of Navajo haematite concretions allow us to infer host-rock properties and fluid processes necessary for similar features to develop on Mars. We conclude that the formation of such spherical haematite concretions requires the presence of a permeable host rock, groundwater flow and a chemical reaction front.

Subsurface Formation Evaluation on Mars: Application of Methods from the Oil Patch

NASA Astrophysics Data System (ADS)

Passey, Q. R.

2006-12-01

The ability to drill 10- to 100-meter deep wellbores on Mars would allow for evaluation of shallow subsurface formations enabling the extension of current interpretations of the geologic history of this planet; moreover, subsurface access is likely to provide direct evidence to determine if water or permafrost is present. Methodologies for evaluating sedimentary rocks using drill holes and in situ sample and data acquisition are well developed here on Earth. Existing well log instruments can measure K, Th, and U from natural spectral gamma-ray emission, compressional and shear acoustic velocities, electrical resistivity and dielectric properties, bulk density (Cs-137 or Co-60 source), photoelectric absorption of gamma-rays (sensitive to the atomic number), hydrogen index from epithermal and thermal neutron scattering and capture, free hydrogen in water molecules from nuclear magnetic resonance, formation capture cross section, temperature, pressure, and elemental abundances (C, O, Si, Ca, H, Cl, Fe, S, and Gd) using 14 MeV pulsed neutron activation more elements possible with supercooled Ge detectors. Additionally, high-resolution wellbore images are possible using a variety of optical, electrical, and acoustic imaging tools. In the oil industry, these downhole measurements are integrated to describe potential hydrocarbon reservoir properties: lithology, mineralogy, porosity, depositional environment, sedimentary and structural dip, sedimentary features, fluid type (oil, gas, or water), and fluid amount (i.e., saturation). In many cases it is possible to determine the organic-carbon content of hydrocarbon source rocks from logs (if the total organic carbon content is 1 wt% or greater), and more accurate instruments likely could be developed. Since Martian boreholes will likely be drilled without using opaque drilling fluids (as generally used in terrestrial drilling), additional instruments can be used such as high resolution direct downhole imaging and other surface contact measurements (such as IR spectroscopy and x-ray fluorescence). However, such wellbores would require modification of some instruments since conventional drilling fluids often provide the coupling of the instrument sensors to the formation (e.g., sonic velocity and galvanic resistivity measurements). The ability to drill wellbores on Mars opens up new opportunities for exploration but also introduces additional technical challenges. Currently it is not known if all existing terrestrial logging instruments can be miniaturized sufficiently for a shallow Mars wellbore, but the existing well logging techniques and instruments provide a solid framework on which to build a Martian subsurface evaluation program.

Exposed Fractured Bedrock in the Central Pit of a Crater

NASA Image and Video Library

2016-11-09

This HiRISE image shows the central pit feature of an approximately 20-kilometer diameter complex crater in located at 304.480 degrees east, -11.860 degrees south, just north of the Valles Marineris. Here we can observe a partial ring of light-toned, massive and fractured bedrock, which has been exposed by the impact-forming event, and via subsequent erosion that typically obscure the bedrock of complex central features. Features such as this one are of particular interest as they provide scientists with numerous exposures of bedrock that can be readily observed from orbit and originate from the deep Martian subsurface. Unlike on Earth, plate tectonics do not appear to be active on Mars. Thus, much of the Martian subsurface is not directly observable through uplift, erosion and exposure of mountain chains, which provide the majority of bedrock exposures on Earth. Exposures of subsurface materials generated by these features provides us with some of the only "windows" into the subsurface geology. This makes the study of impact craters an invaluable source of information when trying to understand, not only the impact process, but also the composition and history of Mars. Although much of what we see here is composed of massive and fractured bedrock, there are zones of rock fragmentation, called "brecciation." These fragmented rocks (a.k.a., breccias) are best viewed in the eastern portion of the central pit, which was captured in a previous HiRISE image. Additionally, we see some occurrences of impact melt-bearing deposits that surround and coat the bedrock exposed within the central pit. Several dunes are on the surface throughout the central pit and surrounding crater floor. The mechanisms behind the formation of central features, particularly central pits, are not completely understood. Geologic mapping of these circumferential "mega" blocks of bedrock indicate radial and concentric fracturing that is consistent with deformation through uplift. The exposed bedrock shows well-expressed lineament features that are likely fractures and faults formed during the uplift process. Studies of the bedrock, and such structures in this image, allows us better to understand the formative events and physical processes responsible for their formation. Current research suggests that their formation is the result of some component of uplift followed by collapse. http://photojournal.jpl.nasa.gov/catalog/PIA21205

A potential new biosignature of life in iron-rich extreme environments: An iron (III) complex of scytonemin and proposal for its identification using Raman spectroscopy

NASA Astrophysics Data System (ADS)

Varnali, Tereza; Edwards, Howell G. M.

2013-07-01

Scytonemin is a cyanobacterial sheath pigment with potent UV absorbing (UV-A, UV-B and UV-C) properties. The importance of this biomolecule is its photoprotective function which is one of the major survival strategies adopted by extremophiles to combat high energy radiation insolation in environmentally stressed conditions. Also, iron (III) oxides offering an additional UV-protecting facility to subsurface biological colonization as well as banded iron formations with zones of iron depletion in rock matrices have attracted attention with special interest in the mobilisation and transportation of iron compounds through the rock. This study represents a novel proposal that an iron-scytonemin complex could facilitate the movement of iron through the subsurface rock as part of the this extremophilic survival strategy. The predicted Raman wavenumbers for the proposed scytonemin complex of iron(III) are derived computationally using DFT calculations. Comparison of the experimentally observed Raman spectra of scytonemin with the theoretically predicted Raman spectra of the iron-scytonemin complex show that the latter may be discriminated and the expected characteristic bands are reported in relation to structural changes that are effected upon complexation. This information will inform the future search for experimental evidence for an iron-scytonemin complex, which has not been recognised hitherto and which could provide a novel biosignature for the extremophilic colonization of terrestrial iron-rich geological matrices. Such a terrestrial scenario would be potentially of significance for the remote robotic analytical exploration of the iron-rich surface and immediate subsurface of Mars.

Study of the Martian Subsurface with a Fiber Optics Spectrometer: the Ma_Miss Experiment

NASA Astrophysics Data System (ADS)

Coradini, A.; de Sanctis, M. C.; Ammannito, E.; Boccaccini, A.; Battistelli, E.; Capanni, A.

2009-04-01

In this presentation is described the investigation that we intend to do with a small imaging spectrometer that will be inserted in the drill of the Exomars- Pasteur rover. This spectrometer is named Ma_miss (Mars Multispectral Imager for Subsurface Studies ). The Ma_Miss experiment is located in the drill ,that will be able to make a hole in the Mars soil and rock up to 2 m. Ma_Miss includes the optical head of the spectrometer, a lamp to illuminate the borehole walls, and the optical fiber that brings the signal to the spectrometer. The multispectral images are acquired by means of a sapphire window placed on the lateral wall of the drill tool, as close as possible to the drill head. The images are gathered by means of an optical fibre system and analyzed using the spectrometer. The Ma_Miss gathered light containing the scientific information is transferred to the array detector and electronics of the instrument by means of an optical rotary joint implemented in the roto-translation group of the drill, as shown in the next pictures In the figure is schematically represented the Ma_Miss- Dibs architecture. This experiment will be extremely valuable since it will allow, for the first time, to have an idea of the mineralogical composition of the Martian subsurface and to study freshly cut rocks. The study of surface and subsurface mineralogy of Martian soil and rocks is the key for understanding the chemico-physical processes that led to the formation and evolution of the Red Planet. The history of the water and other volatiles, as well as the signatures of weathering processes are important to understand present and past environmental conditions associated with the possibility of life. Surface samples are highly influenced by exogenous processes (weathering, erosion, sedimentation, impact) that alter their original properties. So, the analyses of uncontaminated samples by means of instrumented drills and in situ analytic stations are the key for unambiguous interpretation of the original environment that leading to the formation of rocks. Analysis of subsurface layers is the only approach that warranties measurements on samples close to their original composition. The upper few meters of the surface materials on Mars play a crucial role in its history, providing important constraints geologic, hydrologic, and climatic to the history of the planet. Drilling into the near-surface crust will provide an opportunity to assess variations in composition, texture, stratification, unconformities, etc. that will help define its lithology and structure, and provide important clues regarding its origin and subsequent evolution. The subsurface material can give information on the evolution of surface sediments (erosion, transport, deposition), on the relation between sediments and bedrock, on the relation between environmental conditions and surface processes permitting to "investigate planetary processes that influence habitability." Investigation of mineralogical composition of near-surface geological materials is needed to fully characterize the geology of the regions that will be visited by the Rover at all appropriate spatial scales, and to interpret the processes that have formed and modified rocks and regolith. Subsurface access, sampling material below the oxidized layer, can be the key to "assess the biological potential of the target environment (past or present)". To date, we have direct observations relative only to the Martian surface. Little is known about the characteristics of the first subsurface layers. The possibility to sample subsurface materials to be delivered to other instruments, and to record the context of the sampled soil doing in situ borehole mineralogical analysis, is fundamental to search for traces of past or present life on Mars. The spectrometer observes a single point target, having 0.1 mm diameter, on the borehole wall surface. Depending on the surface features we are interested in, the observation window can scan the borehole's surface by means of drill tip rotation or translation. When the drill is translated, a "Column Image" is acquired. This translation step can be equal to the observation spot (0.1 mm). The "Ring Image" can be obtained by rotation of the drill tip; a rotation step of about 0.5˚ (corresponding to 720 acquisitions in the ring) is sufficient to assure the full coverage of the ring.

Microbial life associated with low-temperature alteration of ultramafic rocks in the Leka ophiolite complex.

PubMed

Daae, F L; Økland, I; Dahle, H; Jørgensen, S L; Thorseth, I H; Pedersen, R B

2013-07-01

Water-rock interactions in ultramafic lithosphere generate reduced chemical species such as hydrogen that can fuel subsurface microbial communities. Sampling of this environment is expensive and technically demanding. However, highly accessible, uplifted oceanic lithospheres emplaced onto continental margins (ophiolites) are potential model systems for studies of the subsurface biosphere in ultramafic rocks. Here, we describe a microbiological investigation of partially serpentinized dunite from the Leka ophiolite (Norway). We analysed samples of mineral coatings on subsurface fracture surfaces from different depths (10-160 cm) and groundwater from a 50-m-deep borehole that penetrates several major fracture zones in the rock. The samples are suggested to represent subsurface habitats ranging from highly anaerobic to aerobic conditions. Water from a surface pond was analysed for comparison. To explore the microbial diversity and to make assessments about potential metabolisms, the samples were analysed by microscopy, construction of small subunit ribosomal RNA gene clone libraries, culturing and quantitative-PCR. Different microbial communities were observed in the groundwater, the fracture-coating material and the surface water, indicating that distinct microbial ecosystems exist in the rock. Close relatives of hydrogen-oxidizing Hydrogenophaga dominated (30% of the bacterial clones) in the oxic groundwater, indicating that microbial communities in ultramafic rocks at Leka could partially be driven by H2 produced by low-temperature water-rock reactions. Heterotrophic organisms, including close relatives of hydrocarbon degraders possibly feeding on products from Fischer-Tropsch-type reactions, dominated in the fracture-coating material. Putative hydrogen-, ammonia-, manganese- and iron-oxidizers were also detected in fracture coatings and the groundwater. The microbial communities reflect the existence of different subsurface redox conditions generated by differences in fracture size and distribution, and mixing of fluids. The particularly dense microbial communities in the shallow fracture coatings seem to be fuelled by both photosynthesis and oxidation of reduced chemical species produced by water-rock reactions. © 2013 John Wiley & Sons Ltd.

Laboratory Simulations of Permeability Pertaining to Biosignature Development and Preservation Potential for Martian Subsurface Habitability

NASA Astrophysics Data System (ADS)

Perl, S. M.; Corsetti, F. A.; Berelson, W.; Nealson, K. H.; Bhartia, R.

2014-12-01

Sedimentological and mineralogical observations indicate that sandstones within the Eagle and Endurance crater sections of the Burns Formation of Meridiani Planum, Mars, were derived from sulfate-bearing altered basalt, possibly from a playa lake, and deposited by eolian and locally subaqueous processes in a eolian dune - sand sheet - interdune setting. Abrasion of rocks within the outcrop outlining Endurance Crater by the MER rover Opportunity revealed void spaces later determined to be secondary pore space created from the dissolution of soluble minerals from multiple groundwater movement (recharge) events. Previous investigations into the secondary porosity and permeability of rocks within the Karatepe section showed that the ability for fluid movement through the vertical sedimentary section was greatest between the Upper and Middle units at the Whatanga contact within Endurance Crater, where secondary porosity was measured to be ~40% of the rock. Our investigations into quantifying subsurface habitability involve simulating the paleo-groundwater environments on the micro-to-mesoscale (sub mm-scale to cm-scale) to determine how preservation potential changes with repeated water-rock interaction, varying fluid chemistry (pH, salinity, T, others), and pressure changes under Earth and Mars conditions. In addition to fluids, microbes (extremophiles) will be introduced into our simulation to observe how changing experimental input conditions impact the growth and development of biotic interactions and eventually biosignatures left behind within sedimentary microtextures. Moreover, detection of biosignatures using visual and UV methods will help inform the M2020 rover mission regarding in-situ analysis of abraded rock outcrops. Finally, results of this work will use terrestrial rocks and fluids from a known Mars analogue (the Rio Tinto basin) in order to aid in determining habitability and survivability in acidic and high saline conditions that are similar to Meridiani Planum, Mars.

Active microbial biofilms in deep poor porous continental subsurface rocks.

PubMed

Escudero, Cristina; Vera, Mario; Oggerin, Monike; Amils, Ricardo

2018-01-24

Deep continental subsurface is defined as oligotrophic environments where microorganisms present a very low metabolic rate. To date, due to the energetic cost of production and maintenance of biofilms, their existence has not been considered in poor porous subsurface rocks. We applied fluorescence in situ hybridization techniques and confocal laser scanning microscopy in samples from a continental deep drilling project to analyze the prokaryotic diversity and distribution and the possible existence of biofilms. Our results show the existence of natural microbial biofilms at all checked depths of the Iberian Pyrite Belt (IPB) subsurface and the co-occurrence of bacteria and archaea in this environment. This observation suggests that multi-species biofilms may be a common and widespread lifestyle in subsurface environments.

Geology of the Powder River Basin, Wyoming and Montana, with reference to subsurface disposal of radioactive wastes

USGS Publications Warehouse

Beikman, Helen M.

1962-01-01

The Powder River Basin is a structural and topographic basin occupying an area of about 20,000 square miles in northeastern Wyoming arid southeastern Montana. The Basin is about 230 miles long in a northwest-southeast direction and is about 100 miles wide. It is bounded on three sides by mountains in which rocks of Precambrian age are exposed. The Basin is asymmetrical with a steep west limb adjacent to the Bighorn Mountains and a gentle east limb adjacent to the Black Hills. Sedimentary rocks within the Basin have a maximum thickness of about 18,000 feet and rocks of every geologic period are represented. Paleozoic rocks are about 2,500 feet thick and consist of marine bonate rocks and sandstone; Mesozoic rocks are about 9,500 feet thick and consist of both marine and nonmarine siltstone and sandstone; and Cenozoic rocks are from 4,000 to 6,000 feet thick and consist of coal-bearing sandstone and shale. Radioactive waste could be stored in the pore space of permeable sandstone or in shale where space could be developed. Many such rock units that could be used for storing radioactive wastes are present within the Powder River Basin. Permeable sandstone beds that may be possible reservoirs for storage of radioactive waste are present throughout the Powder River Basin. These include sandstone beds in the Flathead Sandstone and equivalent strata in the Deadwood Formation, the Tensleep Sandstone and equivalent strata in the Minnelusa Formation and the Sundance Formation in rocks of pre-Cretaceous age. However, most of the possible sandstone reservoirs are in rocks of Cretaceous age and include sandstone beds in the Fall River, Lakota, Newcastle, Frontier, Cody, and Mesaverde Formations. Problems of containment of waste such as clogging of pore space and chemical incompatibility would have to be solved before a particular sandstone unit could be selected for waste disposal. Several thick sequences of impermeable shale such as those in the Skull Creek, Mowry, Frontier, Belle Fourche, Cody, Lewis, and Pierre Formations, occur in rocks of Cretaceous age in the Basin. Limited storage space for liquid waste might be developed in impermeable shale by fracturing the shale and space for calcined or fused waste could be developed by mining cavities.

Volcanic settings and their reservoir potential: An outcrop analog study on the Miocene Tepoztlán Formation, Central Mexico

NASA Astrophysics Data System (ADS)

Lenhardt, Nils; Götz, Annette E.

2011-07-01

The reservoir potential of volcanic and associated sedimentary rocks is less documented in regard to groundwater resources, and oil and gas storage compared to siliciclastic and carbonate systems. Outcrop analog studies within a volcanic setting enable to identify spatio-temporal architectural elements and geometric features of different rock units and their petrophysical properties such as porosity and permeability, which are important information for reservoir characterization. Despite the wide distribution of volcanic rocks in Mexico, their reservoir potential has been little studied in the past. In the Valley of Mexico, situated 4000 m above the Neogene volcanic rocks, groundwater is a matter of major importance as more than 20 million people and 42% of the industrial capacity of the Mexican nation depend on it for most of their water supply. Here, we present porosity and permeability data of 108 rock samples representing five different lithofacies types of the Miocene Tepoztlán Formation. This 800 m thick formation mainly consists of pyroclastic rocks, mass flow and fluvial deposits and is part of the southern Transmexican Volcanic Belt, cropping out south of the Valley of Mexico and within the two states of Morelos and Mexico State. Porosities range from 1.4% to 56.7%; average porosity is 24.8%. Generally, permeabilities are low to median (0.2-933.3 mD) with an average permeability of 88.5 mD. The lavas are characterized by the highest porosity values followed by tuffs, conglomerates, sandstones and tuffaceous breccias. On the contrary, the highest permeabilities can be found in the conglomerates, followed by tuffs, tuffaceous breccias, sandstones and lavas. The knowledge of these petrophysical rock properties provides important information on the reservoir potential of volcanic settings to be integrated to 3D subsurface models.

Biofilm formation and potential for iron cycling in serpentinization-influenced groundwater of the Zambales and Coast Range ophiolites.

PubMed

Meyer-Dombard, D'Arcy R; Casar, Caitlin P; Simon, Alexander G; Cardace, Dawn; Schrenk, Matthew O; Arcilla, Carlo A

2018-05-01

Terrestrial serpentinizing systems harbor microbial subsurface life. Passive or active microbially mediated iron transformations at alkaline conditions in deep biosphere serpentinizing ecosystems are understudied. We explore these processes in the Zambales (Philippines) and Coast Range (CA, USA) ophiolites, and associated surface ecosystems by probing the relevance of samples acquired at the surface to in situ, subsurface ecosystems, and the nature of microbe-mineral associations in the subsurface. In this pilot study, we use microcosm experiments and batch culturing directed at iron redox transformations to confirm thermodynamically based predictions that iron transformations may be important in subsurface serpentinizing ecosystems. Biofilms formed on rock cores from the Zambales ophiolite on surface and in-pit associations, confirming that organisms from serpentinizing systems can form biofilms in subsurface environments. Analysis by XPS and FTIR confirmed that enrichment culturing utilizing ferric iron growth substrates produced reduced, magnetic solids containing siderite, spinels, and FeO minerals. Microcosms and enrichment cultures supported organisms whose near relatives participate in iron redox transformations. Further, a potential 'principal' microbial community common to solid samples in serpentinizing systems was identified. These results indicate collectively that iron redox transformations should be more thoroughly and universally considered when assessing the function of terrestrial subsurface ecosystems driven by serpentinization.

Using electrical resistance tomography to map subsurface temperatures

DOEpatents

Ramirez, A.L.; Chesnut, D.A.; Daily, W.D.

1994-09-13

A method is provided for measuring subsurface soil or rock temperatures remotely using electrical resistivity tomography (ERT). Electrical resistivity measurements are made using electrodes implanted in boreholes driven into the soil and/or at the ground surface. The measurements are repeated as some process changes the temperatures of the soil mass/rock mass. Tomographs of electrical resistivity are calculated based on the measurements using Poisson's equation. Changes in the soil/rock resistivity can be related to changes in soil/rock temperatures when: (1) the electrical conductivity of the fluid trapped in the soil's pore space is low, (2) the soil/rock has a high cation exchange capacity and (3) the temperature changes are sufficiently high. When these three conditions exist the resistivity changes observed in the ERT tomographs can be directly attributed to changes in soil/rock temperatures. This method provides a way of mapping temperature changes in subsurface soils remotely. Distances over which the ERT method can be used to monitor changes in soil temperature range from tens to hundreds of meters from the electrode locations. 1 fig.

Using electrical resistance tomography to map subsurface temperatures

DOEpatents

Ramirez, Abelardo L.; Chesnut, Dwayne A.; Daily, William D.

1994-01-01

A method is provided for measuring subsurface soil or rock temperatures remotely using electrical resistivity tomography (ERT). Electrical resistivity measurements are made using electrodes implanted in boreholes driven into the soil and/or at the ground surface. The measurements are repeated as some process changes the temperatures of the soil mass/rock mass. Tomographs of electrical resistivity are calculated based on the measurements using Poisson's equation. Changes in the soil/rock resistivity can be related to changes in soil/rock temperatures when: (1) the electrical conductivity of the fluid trapped in the soil's pore space is low, (2) the soil/rock has a high cation exchange capacity and (3) the temperature changes are sufficiently high. When these three conditions exist the resistivity changes observed in the ERT tomographs can be directly attributed to changes in soil/rock temperatures. This method provides a way of mapping temperature changes in subsurface soils remotely. Distances over which the ERT method can be used to monitor changes in soil temperature range from tens to hundreds of meters from the electrode locations.

System and method for investigating sub-surface features of a rock formation using compressional acoustic sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt

A system and method for investigating rock formations outside a borehole are provided. The method includes generating a first compressional acoustic wave at a first frequency by a first acoustic source; and generating a second compressional acoustic wave at a second frequency by a second acoustic source. The first and the second acoustic sources are arranged within a localized area of the borehole. The first and the second acoustic waves intersect in an intersection volume outside the borehole. The method further includes receiving a third shear acoustic wave at a third frequency, the third shear acoustic wave returning to themore » borehole due to a non-linear mixing process in a non-linear mixing zone within the intersection volume at a receiver arranged in the borehole. The third frequency is equal to a difference between the first frequency and the second frequency.« less

The story of Amazonian climate change on Mars as told by carbonates in Miller Range Nakhlites

NASA Astrophysics Data System (ADS)

Evans, M. E.; Niles, P. B.; Locke, D.; Chapman, P.

2017-12-01

This is a story about rocks from Mars, and how they reveal environmental changes on Mars. A specific region of volcanic rocks formed on Mars about 1.3 billion years ago (bya). This region is now known as the Nakhla lava pile. The rocks were likely formed near the surface. Chemical analysis of these rocks confirms that they formed on Mars, because rocks on Earth have different oxygen isotope values. Sometime later, perhaps 0.7 bya, very small amounts of subsurface water on Mars percolated through the lava pile. The water contained dissolved carbon dioxide (CO2) from contact with the atmosphere of Mars. Ions in the water bonded with rock ions to create tiny, white, carbonate minerals along the cracks within the lava pile. The Nakhla subsurface water temperature was likely cool ( 15°C), which is different from the hot water that possibly created minerals on older Mars rocks. About 11 million years ago, an asteroid impacted Mars over the Nakhla lava pile. The impact rebound ejected mass from the surface and subsurface, and some rocks escaped the gravity of Mars. These rocks floated in space for over 10.9 million years before they fell to Earth as meteorites. The most famous of these meteorites, named Nakhla, fell over Egypt in 1911 and fragmented into 40 pieces. A total of 11 similar meteorites, known as Nakhlites, have been collected across the Earth. Four of these meteorites fell into a remote region of Antarctica called the Miller Range (MIL). They were collected by the National Science Foundation (NSF) "Antarctica Search for Meteorite" (ANSMET) program. This study analyzed the stable isotope geochemistry of the carbonates on the four MIL Nakhlites. Antarctica is an analog for carbonate formation on recent Mars because it forms the minerals in a cold environment with a thin film of water. Carbonates from oceans are dominated by the oxygen isotopic values of the water, but in Mars and Antarctica the carbonates are also influenced by the oxygen in the atmospheric CO2. This study reveals that terrestrial carbonates have different carbon isotope values from martian carbonates. The carbon isotope values of the Mars atmospheric CO2 that formed the MIL Nakhlite carbonates was different from the modern atmosphere (as measured by the MSL Curiosity rover). This difference may be due somewhat to loss of atmospheric gas to space over the past billion years.

Aquifers survey in the context of source rocks exploitation: from baseline acquisition to long term monitoring

NASA Astrophysics Data System (ADS)

Garcia, Bruno; Rouchon, Virgile; Deflandre, Jean-Pierre

2017-04-01

Producing hydrocarbons from source rocks (like shales: a mix of clays, silts, carbonate and sandstone minerals containing matured organic matter, i.e. kerogen oil and gas, but also non-hydrocarbon various species of chemical elements including sometimes radioactive elements) requires to create permeability within the rock matrix by at least hydraulically fracturing the source rock. It corresponds to the production of hydrocarbon fuels that have not been naturally expelled from the pressurized matured source rock and that remain trapped in the porosity or/and kerogen porosity of the impermeable matrix. Azimuth and extent of developed fractures can be respectively determined and mapped by monitoring the associated induced microseismicity. This allows to have an idea of where and how far injected fluids penetrated the rock formation. In a geological context, aquifers are always present in the vicinity -or on fluid migration paths- of such shale formations: deep aquifers (near the shale formation) up to sub-surface and potable (surface) aquifers. Our purpose will be to track any unsuitable invasion or migration of chemicals specifies coming from matured shales of production fluids including both drilling and fracturing ones into aquifers. Our objective is to early detect and alarm of any anomaly to avoid any important environmental issue. The approach consists in deploying a specific sampling tool within a well to recover formation fluids and to run a panoply of appropriate laboratory tests to state on fluid characteristics. Of course for deep aquifers, such a characterization process may consider aquifer properties prior producing shale oil and gas, as they may contain naturally some chemical species present in the source rocks. One can also consider that a baseline acquisition could be justified in case of possible previous invasion of non-natural fluids in the formation under survey (due to any anthropogenic action at surface or in the underground). The paper aims at presenting the protocol and routine test we propose to make our early detection approach efficient for production of shale hydrocarbon fluids, in considering the source-rock reservoir itself, the aquifers, and also the chemical species present in the fluids that are used for hydraulic fracturing operations.

A CO2-Silica Geothermometer for Low Temperature Geothermal Resource Assessment, with Application to Resources in the Safford Basin, Arizona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witcher, James C.; Stone, Claudia

1983-11-01

Geothermics is the study of the earth's heat energy, it's affect on subsurface temperature distribution, it's physical and chemical sources, and it's role in dynamic geologic processes. The term, geothermometry, is applied to the determination of equilibrium temperatures of natural chemical systems, including rock, mineral, and liquid phases. An assemblage of minerals or a chemical system whose phase composition is a function of temperature and pressure can be used as a geothermometer. Thus a geothermometer is useful to determine the formation temperature of rock or the last equilibrium temperature of a flowing aqueous solution such as ground water and hydrothermalmore » fluids.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodge, D.S.

The potential of geothermal energy for future electric power generation in New York State is evaluated using estimates of temperatures of geothermal reservoir rocks. Bottom hole temperatures from over 2000 oil and gas wells in the region were integrated into subsurface maps of the temperatures for specific geothermal reservoirs. The Theresa/Potsdam formation provides the best potential for extraction of high volumes of geothermal fluids. The evaluation of the Theresa/Potsdam geothermal reservoir in upstate New York suggests that an area 30 miles east of Elmira, New York has the highest temperatures in the reservoir rock. The Theresa/Potsdam reservoir rock should havemore » temperatures about 136 {degrees}C and may have as much as 450 feet of porosity in excess of 8%. Estimates of the volumes of geothermal fluids that can be extracted are provided and environmental considerations for production from a geothermal well is discussed.« less

Evidence for Seismogenic Hydrogen Gas, a Potential Microbial Energy Source on Earth and Mars.

PubMed

McMahon, Sean; Parnell, John; Blamey, Nigel J F

2016-09-01

The oxidation of molecular hydrogen (H2) is thought to be a major source of metabolic energy for life in the deep subsurface on Earth, and it could likewise support any extant biosphere on Mars, where stable habitable environments are probably limited to the subsurface. Faulting and fracturing may stimulate the supply of H2 from several sources. We report the H2 content of fluids present in terrestrial rocks formed by brittle fracturing on fault planes (pseudotachylites and cataclasites), along with protolith control samples. The fluids are dominated by water and include H2 at abundances sufficient to support hydrogenotrophic microorganisms, with strong H2 enrichments in the pseudotachylites compared to the controls. Weaker and less consistent H2 enrichments are observed in the cataclasites, which represent less intense seismic friction than the pseudotachylites. The enrichments agree quantitatively with previous experimental measurements of frictionally driven H2 formation during rock fracturing. We find that conservative estimates of current martian global seismicity predict episodic H2 generation by Marsquakes in quantities useful to hydrogenotrophs over a range of scales and recurrence times. On both Earth and Mars, secondary release of H2 may also accompany the breakdown of ancient fault rocks, which are particularly abundant in the pervasively fractured martian crust. This study strengthens the case for the astrobiological investigation of ancient martian fracture systems. Deep biosphere-Faults-Fault rocks-Seismic activity-Hydrogen-Mars. Astrobiology 16, 690-702.

A data driven model for the impact of IFT and density variations on CO2 sequestration in porous media

NASA Astrophysics Data System (ADS)

Nomeli, Mohammad; Riaz, Amir

2017-11-01

CO2 storage in geological formations is one of the most promising solutions for mitigating the amount of greenhouse gases released into the atmosphere. One of the important issues for CO2 storage in subsurface environments is the sealing efficiency of low-permeable cap-rocks overlying potential CO2 storage reservoirs. A novel model is proposed to find the IFT of the systems (CO2/brine-salt) in a range of temperatures (300-373 K), pressures (50-250 bar), and up to 6 molal salinity applicable to CO2 storage in geological formations through a machine learning-assisted modeling of experimental data. The IFT between mineral surfaces and CO2/brine-salt solutions determines the efficiency of enhanced oil or gas recovery operations as well as our ability to inject and store CO2 in geological formations. Finally, we use the new model to evaluate the effects of formation depth on the actual efficiency of CO2 storage. The results indicate that, in the case of CO2 storage in deep subsurface environments as a global-warming mitigation strategy, CO2 storage capacity are improved with reservoir depth.

Numerical investigation on the implications of spring temperature and discharge rate with respect to the geothermal background in a fault zone

NASA Astrophysics Data System (ADS)

Jiang, Zhenjiao; Xu, Tianfu; Mariethoz, Gregoire

2018-04-01

Geothermal springs are some of the most obvious indicators of the existence of high-temperature geothermal resources in the subsurface. However, geothermal springs can also occur in areas of low average subsurface temperatures, which makes it difficult to assess exploitable zones. To address this problem, this study quantitatively analyzes the conditions associated with the formation of geothermal springs in fault zones, and numerically investigates the implications that outflow temperature and discharge rate from geothermal springs have on the geothermal background in the subsurface. It is concluded that the temperature of geothermal springs in fault zones is mainly controlled by the recharge rate from the country rock and the hydraulic conductivity in the fault damage zone. Importantly, the topography of the fault trace on the land surface plays an important role in determining the thermal temperature. In fault zones with a permeability higher than 1 mD and a lateral recharge rate from the country rock higher than 1 m3/day, convection plays a dominant role in the heat transport rather than thermal conduction. The geothermal springs do not necessarily occur in the place having an abnormal geothermal background (with the temperature at certain depth exceeding the temperature inferred by the global average continental geothermal gradient of 30 °C/km). Assuming a constant temperature (90 °C here, to represent a normal geothermal background in the subsurface at a depth of 3,000 m), the conditions required for the occurrence of geothermal springs were quantitatively determined.

Looking For a Needle in the Haystack: Deciphering Indigenous 1.79 km Deep Subsurface Microbial Communities from Drilling Mud Contaminants Using 454 Pyrotag Sequencing

NASA Astrophysics Data System (ADS)

Dong, Y.; Cann, I.; Mackie, R.; Price, N.; Flynn, T. M.; Sanford, R.; Miller, P.; Chia, N.; Kumar, C. G.; Kim, P.; Sivaguru, M.; Fouke, B. W.

2010-12-01

Knowledge of the composition, structure and activity of microbial communities that live in deeply buried sedimentary rocks is fundamental to the future of subsurface biosphere stewardship as it relates to hydrocarbon exploration and extraction, carbon sequestration, gas storage and groundwater management. However, the study of indigenous subsurface microorganisms has been limited by the technical challenges of collecting deep formation water samples that have not been heavily contaminated by the mud used to drill the wells. To address this issue, a “clean-sampling method” deploying the newly developed Schlumberger Quicksilver MDT probe was used to collect a subsurface sample at a depth of 1.79 km (5872 ft) from an exploratory well within Cambrian-age sandstones in the Illinois Basin. This yielded a formation water sample that was determined to have less than 4% drilling mud contamination based on tracking changes in the aqueous geochemistry of the formation water during ~3 hours of pumping at depth prior to sample collection. A suite of microscopy and culture-independent molecular analyses were completed using the DNA extracted from microbial cells in the formation water, which included 454 amplicon pyrosequencing that targeted the V1-V3 hypervariable region of bacterial 16S rRNA gene sequences. Results demonstrated an extremely low diversity microbial community living in formation water at 1.79 km-depth. More than 95 % of the total V1-V3 pyrosequencing reads (n=11574) obtained from the formation water were affiliated with a halophilic γ-proteobacterium and most closely related to the genus Halomonas. In contrast, about 3 % of the V1-V3 sequences in the drilling mud library (n=13044) were classified as genus Halomonas but were distinctly different and distantly related to the formation water Halomonas detected at 1.79 km-depth. These results were consistent with those obtained using a suite of other molecular screens (e.g., Terminal-Restriction Fragment Length Polymorphism (T-RFLP) and the initial full length 16S rRNA amplicon libraries) and bioinformatic analyses (e.g., 16S rRNA and Open Reading Frame (ORF) calls established from the 454 metagenomic community analyses). Functional pathway modeling is underway to evaluate the adaptation of this indigenous microbial community to the hydrologic and geologic history of the deep subsurface environment of the Illinois Basin.

Theoretical study of novel complexed structures for methoxy derivatives of scytonemin: potential biomarkers in iron-rich stressed environments.

PubMed

Varnali, Tereza; Edwards, Howell G M

2013-09-01

Scytonemin is a cyanobacterial sheath pigment with potent UV (UVA, UVB, and UVC) absorbing properties. Di- and tetramethoxy derivatives of scytonemin have also been found and described in the literature. The importance of these biomolecules is their photoprotective function, which is one of the major survival strategies adopted by extremophiles in environmentally stressed conditions. Also, iron compounds [particularly iron(III) oxides] offer an additional UV-protecting facility to subsurface endolithic biological colonization; hence, banded iron formations (accompanied by zones of depletion of iron) in rock matrices have attracted attention with special interest in the method of transportation of iron compounds through the rock. Di- and tetramethoxyscytonemin and their iron(III) complexes have been modeled and studied computationally by using density functional theory calculations at the level of B3LYP/6-31G** methodology. We propose new structures that could feature in survival strategy and facilitate the movement of iron through the rock especially for iron-rich stressed terrestrial environments exemplified by the Río Tinto system with the added potential of subsurface Mars exploration. This study represents a continuation of our previous work on scytonemin. The calculated Raman spectra of the proposed iron complexes are compared with those of their parent compounds and discussed in relation to structural changes effected in the parent ligand upon complexation. This information leads to new insights to be gained by experimental Raman spectroscopists and the characterization of spectroscopic biosignatures for the database being compiled for the remote Raman analytical interrogation of the martian surface and subsurface being proposed for the ESA ExoMars mission planned for launch in 2018.

Preliminary three-dimensional geohydrologic framework of the San Antonio Creek Groundwater Basin, Santa Barbara County, California

NASA Astrophysics Data System (ADS)

Cromwell, G.; Sweetkind, D. S.; O'leary, D. R.

2017-12-01

The San Antonio Creek Groundwater Basin is a rural agricultural area that is heavily dependent on groundwater to meet local water demands. The U.S. Geological Survey (USGS) is working cooperatively with Santa Barbara County and Vandenberg Air Force Base to assess the quantity and quality of the groundwater resources within the basin. As part of this assessment, an integrated hydrologic model that will help stakeholders to effectively manage the water resources in the basin is being developed. The integrated hydrologic model includes a conceptual model of the subsurface geology consisting of stratigraphy and variations in lithology throughout the basin. The San Antonio Creek Groundwater Basin is a relatively narrow, east-west oriented valley that is structurally controlled by an eastward-plunging syncline. Basin-fill material beneath the valley floor consists of relatively coarse-grained, permeable, marine and non-marine sedimentary deposits, which are underlain by fine-grained, low-permeability, marine sedimentary rocks. To characterize the system, surficial and subsurface geohydrologic data were compiled from geologic maps, existing regional geologic models, and lithology and geophysical logs from boreholes, including two USGS multiple-well sites drilled as part of this study. Geohydrologic unit picks and lithologic variations are incorporated into a three-dimensional framework model of the basin. This basin (model) includes six geohydrologic units that follow the structure and stratigraphy of the area: 1) Bedrock - low-permeability marine sedimentary rocks; 2) Careaga Formation - fine to coarse grained near-shore sandstone; 3) Paso Robles Formation, lower portion - sandy-gravely deposits with clay and limestone; 4) Paso Robles Formation, middle portion - clayey-silty deposits; 5) Paso Robles Formation, upper portion - sandy-gravely deposits; and 6) recent Quaternary deposits. Hydrologic data show that the upper and lower portions of the Paso Robles Formation are the primary grou­ndwater-bearing units within the basin, and that the fine-grained layer within this Formation locally restricts vertical groundwater flow.

Seismic properties of fluid bearing formations in magmatic geothermal systems: can we directly detect geothermal activity with seismic methods?

NASA Astrophysics Data System (ADS)

Grab, Melchior; Scott, Samuel; Quintal, Beatriz; Caspari, Eva; Maurer, Hansruedi; Greenhalgh, Stewart

2016-04-01

Seismic methods are amongst the most common techniques to explore the earth's subsurface. Seismic properties such as velocities, impedance contrasts and attenuation enable the characterization of the rocks in a geothermal system. The most important goal of geothermal exploration, however, is to describe the enthalpy state of the pore fluids, which act as the main transport medium for the geothermal heat, and to detect permeable structures such as fracture networks, which control the movement of these pore fluids in the subsurface. Since the quantities measured with seismic methods are only indirectly related with the fluid state and the rock permeability, the interpretation of seismic datasets is difficult and usually delivers ambiguous results. To help overcome this problem, we use a numerical modeling tool that quantifies the seismic properties of fractured rock formations that are typically found in magmatic geothermal systems. We incorporate the physics of the pore fluids, ranging from the liquid to the boiling and ultimately vapor state. Furthermore, we consider the hydromechanics of permeable structures at different scales from small cooling joints to large caldera faults as are known to be present in volcanic systems. Our modeling techniques simulate oscillatory compressibility and shear tests and yield the P- and S-wave velocities and attenuation factors of fluid saturated fractured rock volumes. To apply this modeling technique to realistic scenarios, numerous input parameters need to be indentified. The properties of the rock matrix and individual fractures were derived from extensive literature research including a large number of laboratory-based studies. The geometries of fracture networks were provided by structural geologists from their published studies of outcrops. Finally, the physical properties of the pore fluid, ranging from those at ambient pressures and temperatures up to the supercritical conditions, were taken from the fluid physics literature. The results of this study allow us to describe the seismic properties as a function of hydrothermal and geological features. We use it in a forward seismic modeling study to examine how the seismic response changes with temporally and/or spatially varying fluid properties.

Reconstructing a hydrogen-driven microbial metabolic network in Opalinus Clay rock

DOE PAGES

Bagnoud, Alexandre; Chourey, Karuna; Hettich, Robert L.; ...

2016-10-14

A significant fraction (~ 20%) of microbial life is found in the terrestrial deep subsurface, yet the metabolic processes extant in those environments are poorly understood. Here we show that H 2, injected into the Opalinus Clay formation in a borehole located 300 meters below the surface, fuels a community of microorganisms with interconnected metabolisms. Metagenomic binning and metaproteomic analysis reveal a complete carbon cycle, driven by autotrophic hydrogen oxidizers. Dead biomass from these organisms is a substrate for a fermenting bacterium that produces acetate as a product. In turn, complete oxidizer heterotrophic sulfate- reducing bacteria utilize acetate and oxidizemore » it to CO 2, closing the cycle. This metabolic reconstruction sheds light onto a hydrogen-driven carbon cycle, and a sunlight-independent ecosystem in the deep subsurface.« less

Element mobilization and immobilization from carbonate rocks between CO2 storage reservoirs and the overlying aquifers during a potential CO2 leakage.

PubMed

Lawter, Amanda R; Qafoku, Nikolla P; Asmussen, R Matthew; Kukkadapu, Ravi K; Qafoku, Odeta; Bacon, Diana H; Brown, Christopher F

2018-04-01

Despite the numerous studies on changes within the reservoir following CO 2 injection and the effects of CO 2 release into overlying aquifers, little or no literature is available on the effect of CO 2 release on rock between the storage reservoirs and subsurface. This is important, because the interactions that occur in this zone between the CO 2 storage reservoir and the subsurface may have a significant impact on risk analysis for CO 2 storage projects. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in this intermediate zone. After rocks reacted with CO 2 -acidified 0.01 M NaCl, liquid analysis showed an increase of major elements (e.g., Ca and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower aqueous concentrations of these elements were observed in N 2 control experiments, likely due to differences in pH between the CO 2 and N 2 experiments. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO 2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO 2 -reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO 2 -laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Element mobilization and immobilization from carbonate rocks between CO 2 storage reservoirs and the overlying aquifers during a potential CO 2 leakage

DOE PAGES

Lawter, Amanda R.; Qafoku, Nikolla P.; Asmussen, R. Matthew; ...

2018-01-04

In spite of the numerous studies on changes within the reservoir following CO 2 injection and the effects of CO 2 release into overlying aquifers, little or no literature is available on the effect of CO 2 release on rock between the storage reservoirs and subsurface. This is important, because the interactions that occur in this zone between the CO 2 storage reservoir and the subsurface may have a significant impact on risk analysis for CO 2 storage projects. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in thismore » intermediate zone. Furthermore, after rocks reacted with CO 2-acidified 0.01 M NaCl, liquid analysis showed an increase of major elements (e.g., Ca and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower aqueous concentrations of these elements were observed in N 2 control experiments, likely due to differences in pH between the CO 2 and N 2 experiments. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO 2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO 2-reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO 2-laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation.« less

Lithologies of the basement complex (Devonian and older) in the National Petroleum Reserve - Alaska

USGS Publications Warehouse

Dumoulin, Julie A.; Houseknecht, David W.

2001-01-01

Rocks of the basement complex (Devonian and older) were encountered in at least 30 exploratory wells in the northern part of the NPRA. Fine-grained, variably deformed sedimentary rocks deposited in a slope or basinal setting predominate and include varicolored (mainly red and green) argillite in the Simpson area, dark argillite and chert near Barrow, and widespread gray argillite. Chitinozoans of Middle-Late Ordovician and Silurian age occur in the dark argillite and chert unit. Sponge spicules and radiolarians establish a Phanerozoic age for the varicolored and gray argillite units, both of which contain local interbeds of chert-rich sandstone and silt-stone. Conglomerate and sandstone, also chert-rich but interbedded with mudstone and coal and of Early-Middle Devonian age, occur in the Topagoruk area; these strata formed in a fluvial environment. At East Teshekpuk, granite of probable Devonian age was penetrated. Brecciated, quartz-veined rock of uncertain protolith that may be part of the basement complex was encountered in the Ikpikpuk well. Seismic data indicate that angular unconformities truncate all sedimentary units of the basement complex in NPRA. Rocks correlative in age and lithofacies with the dark argillite and chert unit occur in the subsurface near Prudhoe Bay. Other argillite units in NPRA have similarities to basement rocks in the subsurface adjacent to ANWR and the Ordovician-Silurian Iviagik Group at Cape Lisburne, but lack the interbedded limestones found in the ANWR strata, and are less metamorphosed than, and compositionally distinct from, the Iviagik. The Topagoruk conglomerate and the East Teshekpuk granite resemble the Ulungarat formation and the Okpilak batholith, respectively, in the northeastern Brooks Range.

Element mobilization and immobilization from carbonate rocks between CO 2 storage reservoirs and the overlying aquifers during a potential CO 2 leakage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawter, Amanda R.; Qafoku, Nikolla P.; Asmussen, R. Matthew

In spite of the numerous studies on changes within the reservoir following CO 2 injection and the effects of CO 2 release into overlying aquifers, little or no literature is available on the effect of CO 2 release on rock between the storage reservoirs and subsurface. This is important, because the interactions that occur in this zone between the CO 2 storage reservoir and the subsurface may have a significant impact on risk analysis for CO 2 storage projects. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in thismore » intermediate zone. Furthermore, after rocks reacted with CO 2-acidified 0.01 M NaCl, liquid analysis showed an increase of major elements (e.g., Ca and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower aqueous concentrations of these elements were observed in N 2 control experiments, likely due to differences in pH between the CO 2 and N 2 experiments. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO 2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO 2-reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO 2-laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation.« less

Subsurface Rock Physical Properties by Downhole Loggings - Case Studies of Continental Deep Drilling in Kanto Distinct, Japan

NASA Astrophysics Data System (ADS)

Omura, K.

2014-12-01

In recent years, many examples of physical logging have been carried out in deep boreholes. The loggings are direct in-situ measurements of rock physical properties under the ground. They provide significant basic data for the geological, geophysical and geotechnical investigations, e.g., tectonic history, seismic wave propagation, and ground motion prediction. Since about 1980's, Natl. Res. Inst. for Earth Sci. and Disast. Prev. (NIED) dug deep boreholes (from 200m to 3000m depth) in sedimentary basin of Kanto distinct, Japan, for purposes of installing seismographs and hydrological instruments, and in-situ stress and pore pressure measurements. At that time, downhole physical loggings were conducted in the boreholes: spontaneous potential, electrical resistance, elastic wave velocity, formation density, neutron porosity, total gamma ray, caliper, temperature loggings. In many cases, digital data values were provided every 2m or 1m or 0.1m. In other cases, we read printed graphs of logging plots and got digital data values. Data from about 30 boreholes are compiled. Especially, particular change of logging data at the depth of an interface between a shallow part (soft sedimentary rock) and a base rock (equivalent to hard pre-Neogene rock) is examined. In this presentation, the correlations among physical properties of rock (especially, formation density, elastic wave velocity and electrical resistance) are introduced and the relation to the lithology is discussed. Formation density, elastic wave velocity and electric resistance data indicate the data are divide in two groups that are higher or lower than 2.5g/cm3: the one correspond to a shallow part and the other correspond to a base rock part. In each group, the elastic wave velocity and electric resistance increase with increase of formation density. However the rates of increases in the shallow part are smaller than in the base rock part. The shallow part has lower degree of solidification and higher porosity than that in the base rock part. It appears differences in the degree of solidification and/or porosity are related to differences in the increasing rates. The present data show that the physical logging data are effective information to explore where the base rock is and what properties of the base rock are different from those in the shallow part.

Biological enhancement of hydrocarbon extraction

DOEpatents

Brigmon, Robin L [North Augusta, SC; Berry, Christopher J [Aiken, SC

2009-01-06

A method of microbial enhanced oil recovery for recovering oil from an oil-bearing rock formation is provided. The methodology uses a consortium of bacteria including a mixture of surfactant producing bacteria and non-surfactant enzyme producing bacteria which may release hydrocarbons from bitumen containing sands. The described bioprocess can work with existing petroleum recovery protocols. The consortium microorganisms are also useful for treatment of above oil sands, ground waste tailings, subsurface oil recovery, and similar materials to enhance remediation and/or recovery of additional hydrocarbons from the materials.

Estimation of Mars radar backscatter from measured surface rock populations

USGS Publications Warehouse

Baron, J.E.; Simpson, R.A.; Tyler, G.L.; Moore, H.J.; Harmon, J.K.

1998-01-01

Reanalysis of rock population data at the Mars Viking Lander sites has yielded updated values of rock fractional surface coverage (about 0.16 at both sites, including outcrops) and new estimates of rock burial depths and axial ratios. These data are combined with a finite difference time domain (FDTD) numerical scattering model to estimate diffuse backscatter due to rocks at both the Lander l (VL1) and Lander 2 (VL2) sites. We consider single scattering from both surface and subsurface objects of various shapes, ranging from an ideal sphere to an accurate digitized model of a terrestrial rock. The FDTD cross-section calculations explicitly account for the size, shape, composition, orientation, and burial state of the scattering object, the incident wave angle and polarization, and the composition of the surface. We calculate depolarized specific cross sections at 12.6 cm wavelength due to lossless rock-like scatterers of about 0.014 at VL1 and 0.023 at VL2, which are comparable to the measured ranges of 0.019-0.032 and 0.012-0.018, respectively. We also discuss the variation of the diffuse cross section as the local angle of incidence, ??i, changes. Numerical calculations for a limited set of rock shapes indicate a marked difference between the angular backscattering behavior of wavelength-scale surface and subsurface rocks: while subsurface rocks scatter approximately as a cosine power law, surface rocks display a complex variation, often with peak backscattering at high incidence angles (??i = 70??-75??). Copyright 1998 by the American Geophysical Union.

Evidence for Seismogenic Hydrogen Gas, a Potential Microbial Energy Source on Earth and Mars

NASA Astrophysics Data System (ADS)

McMahon, Sean; Parnell, John; Blamey, Nigel J. F.

2016-09-01

The oxidation of molecular hydrogen (H2) is thought to be a major source of metabolic energy for life in the deep subsurface on Earth, and it could likewise support any extant biosphere on Mars, where stable habitable environments are probably limited to the subsurface. Faulting and fracturing may stimulate the supply of H2 from several sources. We report the H2 content of fluids present in terrestrial rocks formed by brittle fracturing on fault planes (pseudotachylites and cataclasites), along with protolith control samples. The fluids are dominated by water and include H2 at abundances sufficient to support hydrogenotrophic microorganisms, with strong H2 enrichments in the pseudotachylites compared to the controls. Weaker and less consistent H2 enrichments are observed in the cataclasites, which represent less intense seismic friction than the pseudotachylites. The enrichments agree quantitatively with previous experimental measurements of frictionally driven H2 formation during rock fracturing. We find that conservative estimates of current martian global seismicity predict episodic H2 generation by Marsquakes in quantities useful to hydrogenotrophs over a range of scales and recurrence times. On both Earth and Mars, secondary release of H2 may also accompany the breakdown of ancient fault rocks, which are particularly abundant in the pervasively fractured martian crust. This study strengthens the case for the astrobiological investigation of ancient martian fracture systems.

North Slope, Alaska: Source rock distribution, richness, thermal maturity, and petroleum charge

USGS Publications Warehouse

Peters, K.E.; Magoon, L.B.; Bird, K.J.; Valin, Z.C.; Keller, M.A.

2006-01-01

Four key marine petroleum source rock units were identified, characterized, and mapped in the subsurface to better understand the origin and distribution of petroleum on the North Slope of Alaska. These marine source rocks, from oldest to youngest, include four intervals: (1) Middle-Upper Triassic Shublik Formation, (2) basal condensed section in the Jurassic-Lower Cretaceous Kingak Shale, (3) Cretaceous pebble shale unit, and (4) Cretaceous Hue Shale. Well logs for more than 60 wells and total organic carbon (TOC) and Rock-Eval pyrolysis analyses for 1183 samples in 125 well penetrations of the source rocks were used to map the present-day thickness of each source rock and the quantity (TOC), quality (hydrogen index), and thermal maturity (Tmax) of the organic matter. Based on assumptions related to carbon mass balance and regional distributions of TOC, the present-day source rock quantity and quality maps were used to determine the extent of fractional conversion of the kerogen to petroleum and to map the original TOC (TOCo) and the original hydrogen index (HIo) prior to thermal maturation. The quantity and quality of oil-prone organic matter in Shublik Formation source rock generally exceeded that of the other units prior to thermal maturation (commonly TOCo > 4 wt.% and HIo > 600 mg hydrocarbon/g TOC), although all are likely sources for at least some petroleum on the North Slope. We used Rock-Eval and hydrous pyrolysis methods to calculate expulsion factors and petroleum charge for each of the four source rocks in the study area. Without attempting to identify the correct methods, we conclude that calculations based on Rock-Eval pyrolysis overestimate expulsion factors and petroleum charge because low pressure and rapid removal of thermally cracked products by the carrier gas retards cross-linking and pyrobitumen formation that is otherwise favored by natural burial maturation. Expulsion factors and petroleum charge based on hydrous pyrolysis may also be high compared to nature for a similar reason. Copyright ?? 2006. The American Association of Petroleum Geologists. All rights reserved.

Subsurface Biodegradation in a Fractured Basement Reservoir, Shropshire, UK

NASA Astrophysics Data System (ADS)

Parnell, John; Baba, Mas'ud; Bowden, Stephen; Muirhead, David

2017-04-01

Subsurface Biodegradation in a Fractured Basement Reservoir, Shropshire, UK. John Parnell, Mas'ud Baba, Stephen Bowden, David Muirhead Subsurface biodegradation in current oil reservoirs is well established, but there are few examples of fossil subsurface degradation. Biomarker compositions of viscous and solid oil residues ('bitumen') in fractured Precambrian and other basement rocks below the Carboniferous cover in Shropshire, UK, show that they are variably biodegraded. High levels of 25-norhopanes imply that degradation occurred in the subsurface. Lower levels of 25-norhopanes occur in active seepages. Liquid oil trapped in fluid inclusions in mineral veins in the fractured basement confirm that the oil was emplaced fresh before subsurface degradation. A Triassic age for the veins implies a 200 million year history of hydrocarbon migration in the basement rocks. The data record microbial colonization of a fractured basement reservoir, and add to evidence in modern basement aquifers for microbial activity in deep fracture systems. Buried basement highs may be especially favourable to colonization, through channelling fluid flow to shallow depths and relatively low temperatures

Aquifer configuration and geostructural links control the groundwater quality in thin-bedded carbonate-siliciclastic alternations of the Hainich CZE, central Germany

NASA Astrophysics Data System (ADS)

Kohlhepp, Bernd; Lehmann, Robert; Seeber, Paul; Küsel, Kirsten; Trumbore, Susan E.; Totsche, Kai U.

2017-12-01

The quality of near-surface groundwater reservoirs is controlled, but also threatened, by manifold surface-subsurface interactions. Vulnerability studies typically evaluate the variable interplay of surface factors (land management, infiltration patterns) and subsurface factors (hydrostratigraphy, flow properties) in a thorough way, but disregard the resulting groundwater quality. Conversely, hydrogeochemical case studies that address the chemical evolution of groundwater often lack a comprehensive analysis of the structural buildup. In this study, we aim to reconstruct the actual spatial groundwater quality pattern from a synoptic analysis of the hydrostratigraphy, lithostratigraphy, pedology and land use in the Hainich Critical Zone Exploratory (Hainich CZE). This CZE represents a widely distributed yet scarcely described setting of thin-bedded mixed carbonate-siliciclastic strata in hillslope terrains. At the eastern Hainich low-mountain hillslope, bedrock is mainly formed by alternated marine sedimentary rocks of the Upper Muschelkalk (Middle Triassic) that partly host productive groundwater resources. Spatial patterns of the groundwater quality of a 5.4 km long well transect are derived by principal component analysis and hierarchical cluster analysis. Aquifer stratigraphy and geostructural links were deduced from lithological drill core analysis, mineralogical analysis, geophysical borehole logs and mapping data. Maps of preferential recharge zones and recharge potential were deduced from digital (soil) mapping, soil survey data and field measurements of soil hydraulic conductivities (Ks). By attributing spatially variable surface and subsurface conditions, we were able to reconstruct groundwater quality clusters that reflect the type of land management in their preferential recharge areas, aquifer hydraulic conditions and cross-formational exchange via caprock sinkholes or ascending flow. Generally, the aquifer configuration (spatial arrangement of strata, valley incision/outcrops) and related geostructural links (enhanced recharge areas, karst phenomena) control the role of surface factors (input quality and locations) vs. subsurface factors (water-rock interaction, cross-formational flow) for groundwater quality in the multi-layered aquifer system. Our investigation reveals general properties of alternating sequences in hillslope terrains that are prone to forming multi-layered aquifer systems. This synoptic analysis is fundamental and indispensable for a mechanistic understanding of ecological functioning, sustainable resource management and protection.

Discontinuities Characteristics of the Upper Jurassic Arab-D Reservoir Equivalent Tight Carbonates Outcrops, Central Saudi Arabia

NASA Astrophysics Data System (ADS)

Abdlmutalib, Ammar; Abdullatif, Osman

2017-04-01

Jurassic carbonates represent an important part of the Mesozoic petroleum system in the Arabian Peninsula in terms of source rocks, reservoirs, and seals. Jurassic Outcrop equivalents are well exposed in central Saudi Arabia and which allow examining and measuring different scales of geological heterogeneities that are difficult to collect from the subsurface due to limitations of data and techniques. Identifying carbonates Discontinuities characteristics at outcrops might help to understand and predict their properties and behavior in the subsurface. The main objective of this study is to identify the lithofacies and the discontinuities properties of the upper Jurassic carbonates of the Arab D member and the Jubaila Formation (Arab-D reservoir) based on their outcrop equivalent strata in central Saudi Arabia. The sedimentologic analysis revealed several lithofacies types that vary in their thickness, abundances, cyclicity and vertical and lateral stacking patterns. The carbonates lithofacies included mudstone, wackestone, packstone, and grainstone. These lithofacies indicate deposition within tidal flat, skeletal banks and shallow to deep lagoonal paleoenvironmental settings. Field investigations of the outcrops revealed two types of discontinuities within Arab D Member and Upper Jubaila. These are depositional discontinuities and tectonic fractures and which all vary in their orientation, intensity, spacing, aperture and displacements. It seems that both regional and local controls have affected the fracture development within these carbonate rocks. On the regional scale, the fractures seem to be structurally controlled by the Central Arabian Graben System, which affected central Saudi Arabia. While, locally, at the outcrop scale, stratigraphic, depositional and diagenetic controls appear to have influenced the fracture development and intensity. The fracture sets and orientations identified on outcrops show similarity to those fracture sets revealed in the upper Jurassic carbonates in the subsurface which suggest inter-relationships. Therefore, the integration of discontinuities characteristics revealed from the Arab-D outcrop with subsurface data might help to understand and predict discontinuity properties and patterns of the Arab-D reservoir in the subsurface.

Simulation of CO2 Sequestration at Rock Spring Uplift, Wyoming: Heterogeneity and Uncertainties in Storage Capacity, Injectivity and Leakage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Hailin; Dai, Zhenxue; Jiao, Zunsheng

2011-01-01

Many geological, geochemical, geomechanical and hydrogeological factors control CO{sub 2} storage in subsurface. Among them heterogeneity in saline aquifer can seriously influence design of injection wells, CO{sub 2} injection rate, CO{sub 2} plume migration, storage capacity, and potential leakage and risk assessment. This study applies indicator geostatistics, transition probability and Markov chain model at the Rock Springs Uplift, Wyoming generating facies-based heterogeneous fields for porosity and permeability in target saline aquifer (Pennsylvanian Weber sandstone) and surrounding rocks (Phosphoria, Madison and cap-rock Chugwater). A multiphase flow simulator FEHM is then used to model injection of CO{sub 2} into the target salinemore » aquifer involving field-scale heterogeneity. The results reveal that (1) CO{sub 2} injection rates in different injection wells significantly change with local permeability distributions; (2) brine production rates in different pumping wells are also significantly impacted by the spatial heterogeneity in permeability; (3) liquid pressure evolution during and after CO{sub 2} injection in saline aquifer varies greatly for different realizations of random permeability fields, and this has potential important effects on hydraulic fracturing of the reservoir rock, reactivation of pre-existing faults and the integrity of the cap-rock; (4) CO{sub 2} storage capacity estimate for Rock Springs Uplift is 6614 {+-} 256 Mt at 95% confidence interval, which is about 36% of previous estimate based on homogeneous and isotropic storage formation; (5) density profiles show that the density of injected CO{sub 2} below 3 km is close to that of the ambient brine with given geothermal gradient and brine concentration, which indicates CO{sub 2} plume can sink to the deep before reaching thermal equilibrium with brine. Finally, we present uncertainty analysis of CO{sub 2} leakage into overlying formations due to heterogeneity in both the target saline aquifer and surrounding formations. This uncertainty in leakage will be used to feed into risk assessment modeling.« less

Noble gas and hydrocarbon tracers in multiphase unconventional hydrocarbon systems: Toward integrated advanced reservoir simulators

NASA Astrophysics Data System (ADS)

Darrah, T.; Moortgat, J.; Poreda, R. J.; Muehlenbachs, K.; Whyte, C. J.

2015-12-01

Although hydrocarbon production from unconventional energy resources has increased dramatically in the last decade, total unconventional oil and gas recovery from black shales is still less than 25% and 9% of the totals in place, respectively. Further, the majority of increased hydrocarbon production results from increasing the lengths of laterals, the number of hydraulic fracturing stages, and the volume of consumptive water usage. These strategies all reduce the economic efficiency of hydrocarbon extraction. The poor recovery statistics result from an insufficient understanding of some of the key physical processes in complex, organic-rich, low porosity formations (e.g., phase behavior, fluid-rock interactions, and flow mechanisms at nano-scale confinement and the role of natural fractures and faults as conduits for flow). Noble gases and other hydrocarbon tracers are capably of recording subsurface fluid-rock interactions on a variety of geological scales (micro-, meso-, to macro-scale) and provide analogs for the movement of hydrocarbons in the subsurface. As such geochemical data enrich the input for the numerical modeling of multi-phase (e.g., oil, gas, and brine) fluid flow in highly heterogeneous, low permeability formations Herein we will present a combination of noble gas (He, Ne, Ar, Kr, and Xe abundances and isotope ratios) and molecular and isotopic hydrocarbon data from a geographically and geologically diverse set of unconventional hydrocarbon reservoirs in North America. Specifically, we will include data from the Marcellus, Utica, Barnett, Eagle Ford, formations and the Illinois basin. Our presentation will include geochemical and geological interpretation and our perspective on the first steps toward building an advanced reservoir simulator for tracer transport in multicomponent multiphase compositional flow (presented separately, in Moortgat et al., 2015).

Compositions produced using an in situ heat treatment process

DOEpatents

Roes, Augustinus Wilhelmus Maria; Nair, Vijay; Munsterman, Erwin Hunh; Van Bergen, Petrus Franciscus; Van Den Berg, Franciscus Gondulfus Antonius

2013-05-28

Methods for treating a subsurface formation and compositions produced therefrom are described herein. At least one method for producing hydrocarbons from a subsurface formation includes providing heat to the subsurface formation using an in situ heat treatment process. One or more formation particles may be formed during heating of the subsurface formation. Fluid that includes hydrocarbons and the formation particles may be produced from the subsurface formation. The formation particles in the produced fluid may include cenospheres and have an average particle size of at least 0.5 micrometers.

Compositions produced using an in situ heat treatment process

DOEpatents

Roes, Augustinus Wilhelmus Maria [Houston, TX; Nair, Vijay [Katy, TX; Munsterman, Erwin Henh [Amsterdam, NL; Van Bergen, Petrus Franciscus [Amsterdam, NL; Van Den Berg, Franciscus Gondulfus Antonius

2009-10-20

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for producing hydrocarbons from a subsurface formation includes providing heat to the subsurface formation using an in situ heat treatment process. One or more formation particles may be formed during heating of the subsurface formation. Fluid that includes hydrocarbons and the formation particles may be produced from the subsurface formation. The formation particles in the produced fluid may include cenospheres and have an average particle size of at least 0.5 micrometers.

Rescuing the Cahoon Mine drill cores: Opportunities for modern mapping of the ca. 1.7 Ga Freedom Formation in southern Wisconsin

NASA Astrophysics Data System (ADS)

Stanley, V.; Stewart, E.

2016-12-01

Rock cores collected during historic mineral exploration can provide invaluable data for modern analyses, but only if the samples are properly curated. The Cahoon Mine operated in Baraboo, WI during the 1910's and produced iron ore from the ca. 1.7 Ga Freedom Formation. The Freedom Formation is part of the well-known Baraboo-interval stratigraphy and is only present in the subsurface of Wisconsin (Weidman, 1904). Seventeen exploratory drill cores were rescued by Wisconsin Geological and Natural History Survey (WGNHS) from the original drying house at the mine site. The condition of the containers endangered the stratigraphic context of the collection; identifiers and depth markings were often obscured or lost. The individual core pieces were coated in residue and dust. Most of what is known about the Freedom Formation is from core logs and master's theses from the early 1900's (Leith, 1935; Schmidt, 1951). Ongoing subsurface mapping of the Baraboo-interval sediments and underlying basement of southern Wisconsin integrates new and existing subsurface and regional geophysical datasets. Mapping involves calibrating unique signals in regional aeromagnetic data to known lithology from drill core and cuttings. The Freedom Formation is especially important in this process as its iron-rich composition and regional continuity causes it to have a somewhat unique signal in regional aeromagnetic data. The Cahoon Mine cores in the WGNHS repository are the most extensive collection of physical samples from the Freedom Formation still in existence. We are in the process of curating the cores to facilitate their use in ongoing bedrock mapping. Today the cost and logistics of extensive sampling of this unit makes the existing core collection irreplaceable. We transferred the material to new containers, digitally recorded metadata, and created archival labels. As a result of this effort, the Cahoon Mine cores are now stored in a format that is physically and digitally accessible.

Porous media of the Red River Formation, Williston Basin, North Dakota: a possible Sedimentary Enhanced Geothermal System

NASA Astrophysics Data System (ADS)

Hartig, Caitlin M.

2018-01-01

Fracture-stimulated enhanced geothermal systems (EGS) can be developed in both crystalline rocks and sedimentary basins. The Red River Formation (Ordovician) is a viable site for development of a sedimentary EGS (SEGS) because the formation temperatures exceed 140 °C and the permeability is 0.1-38 mD; fracture stimulation can be utilized to improve permeability. The spatial variations of the properties of the Red River Formation were analyzed across the study area in order to understand the distribution of subsurface formation temperatures. Maps of the properties of the Red River Formation-including depth to the top of the formation, depth to the bottom of the formation, porosity, geothermal gradient, heat flow, and temperature-were produced by the Kriging interpolation method in ArcGIS. In the future, these results may be utilized to create a reservoir simulation model of an SEGS in the Red River Formation; the purpose of this model would be to ascertain the thermal response of the reservoir to fracture stimulation.

Geology of the Jewel Cave SW Quadrangle, Custer County, South Dakota

USGS Publications Warehouse

Braddock, William A.

1963-01-01

The Jewel Cave SW quadrangle is in the southwestern part of the Black Hills in Custer County, S. Dak., about midway between Edgemont, S. Dak., and Newcastle, Wyo. All the rocks that crop out within the quadrangle are of sedimentary origin and range in age from Pennsylvanian to Early Cretaceous. The Minnesota Formation of Pennsylvania and Permian age, which is about 1,000 feet thick, was studied in outcrop and from two diamond-drill cores. In the subsurface the upper part of the formation consists of gray sandstone, very fine grained dolomite, and anhydrite. The anhydrite has been leached from the formation near the outcrop, perhaps in the early part of the Cenozoic Era, and the resulting subsidence has produced collapse breccias in the Minnelusa and milder deformation in the overlying units. In the collapse breccias the rocks have been oxidized and are red, whereas in the subsurface they are gray. The anhydrite cement of the subsurface sandstone has been replaced by calcite, and the dolomite beds have been partially converted to limestone. The Opeche Formation of Permian age consists of 75 to 115 feet of red siltstone and shale and two thin gypsum beds. The Minnekahta Limestone of Permian age is about 40 feet thick. The Spearfish Formation of Permian and Triassic age is about 550 feet thick and consists of red siltstone red sandstone, dolomite, and gypsum. The dolomite and gypsum beds are restricted to the lower half of the formation. In the northeast corner of the quadrangle the gypsum beds have been dissolved by ground water. The Sundance Formation of Late Jurassic age is divided into five members that have a total thickness of about 360 feet. The Morrison Formation of Late Jurassic age ranges in thickness from 60 to 120 feet. It consists of blocky weathering noncarbonaceous mudstone and subordinate beds of limestone and sandstone. The Inyan Kara Group of Early Cretaceous age has been subdivided into the Lakota Formation and the Fall River Formation. The Lakota Formation consists of 200 to 300 feet of carbonaceous siltstone blocky-weathering claystone, and fine-grained to conglomeratic sandstone. These rocks were deposited in stream channels, flood plains, and ponds. The Fall River Formation is about 110 to 130 feet thick. Along the northeast side of the outcrop the formation consists of fine- to medium-grained sandstone, which forms an elongate body at least 1-1/2 miles wide and more than 25 miles long. To the southwest the formation consists of thinly stratified interbedded sandstone, carbonaceous siltstone, and varicolored mudstone. The Skull Creek and Mowry Shales of Early Cretaceous age consist of black fissile shale. The Mowry contains abundant fish scales and weathers to a silver gray. Alluvium fills the bottom of many intermittent streams, and small gravel-covered terraces mark the former high levels of these streams. Gravel, which caps hills at altitudes of 4,460 to 4,620 feet, is believed to have been deposited by a Pleistocene stream that drained southeastward toward the town of Minnekahta. Many landslides are present along the northward- and eastward-facing scarp of the Inyan Kara hogback. The Dewey fault, trending N. 75 deg E., crosses the quadrangle. It is probably a vertical dip-slip fault, and has an apparent displacement of 250 to 440 feet. Two northwest-trending anticlines are in the quadrangle - one extends from the Edgemont NE quadrangle to near the center of the Jewel Cave SW quadrangle, and the other is limited to the center of the Jewel Cave SW quadrangle. Collapse structures, which were produced by the solution of anhydrite, are (a) breccias in the Minnelusa Formation, (b) limestone-dolomite breccias in the Spearfish Formation, (c) undulations and normal faults in the formations overlying the Minnelusa and (d) breccia pipes that extend upward from the Minnelusa to at least as high as the Lakota Formation. The leaching probably occurred in early Cenozoic time. Minor deformationa

Geochemical Analysis of Parasequences within the Productive Middle Member of the Eagle Ford Formation at Lozier Canyon near Del Rio, Texas

NASA Astrophysics Data System (ADS)

Shane, Timothy E.

The middle member of the Eagle Ford formation is a heterogeneous, carbonate-shale unit that is a focus of unconventional oil and gas exploration in southern Texas. Exploration results have been mixed because of the apparent heterogeneity of the member. In this study, the extent of heterogeneities in the Eagle Ford on the "bedding-scale" were examined by evaluating changes in organic and inorganic geochemistry. Samples were collected vertically in outcrop covering four non-consecutive parasequences. These samples were analyzed using a Rock Eval 6 Analyzer(TM) to determine source rock generative potential and a Niton(TM) XRF to evaluate inorganic geochemistry to identify changes in paleoredox conditions, paleoproductivity, and clastic influx. From pyrolysis data, it is determined that Parasequence 1 potentially displays an increase in source rock potential, Parasequence 2 potentially displays a constant source rock potential, and Parasequences 3 and 4 potentially display overall decreases in source rock potential during deposition. From the inferred paleoredox conditions, paleoproductivity, and clastic influx, it is determined that Parasequence 1 experienced a potential increase in oxygen abundance, Parasequence 2 experienced a potential decrease in oxygen abundance, and Parasequences 3 and 4 potentially experienced increases in oxygen abundance during deposition. It is concluded that geochemical heterogeneities do exist on a bedding scale within the parasequences of the middle member of the Eagle Ford. Additional comprehensive sampling and analysis is recommended in the future in order to tie these data to subsurface data for economic application.

Relationship between mineralogy and porosity in seals relevant to geologic CO2 Sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swift, Alexander; Anovitz, Lawrence; Sheets, Julia

2014-01-01

Porosity and permeability are key petrophysical variables that link the thermal, hydrological, geochemical, and geomechanical properties of subsurface formations. The size, shape, distribution, and connectivity of rock pores dictate how fluids migrate into and through micro- and nano-environments, then wet and react with accessible solids. Three representative samples of cap rock from the Eau Claire Formation, the prospective sealing unit that overlies the Mount Simon Sandstone, a potential CO 2 storage formation, were interrogated with an array of complementary methods. neutron scattering, backscattered-electron imaging, energydispersive spectroscopy, and mercury porosimetry. Results are presented that detail variations between lithologic types in totalmore » and connected nano- to microporosity across more than five orders of magnitude. Pore types are identified and then characterized according to presence in each rock type, relative abundance, and surface area of adjacent minerals, pore and pore-throat diameters, and degree of connectivity. We observe a bimodal distribution of porosity as a function of both pore diameter and pore-throat diameter. The contribution of pores at the nano- and microscales to the total and the connected porosity is a distinguishing feature of each lithology observed. Pore:pore-throat ratios at each of these two scales diverge markedly, being almost unity at the nanoscale regime (dominated by illitic clay and micas), and varying by one and a half orders of magnitude at the microscale within a clastic mudstone.« less

The Implementation of 2-D Resistivity Method in Verifying Paleozoic Aquifer Properties at Bukit Chondong, Perlis (Malaysia)

NASA Astrophysics Data System (ADS)

Maslinda, Umi; Nordiana, M. M.; Bery, A. A.; Afiq Saharudin, Muhamad; Hisham, Hazrul; Taqiuddin, Z. M.; Sulaiman, Nabila; Nur Amalina, M. K. A.; Nordiana, A. N.

2017-04-01

The research was conducted using 2-D resistivity in verifying Paleozoic aquifer. Since most geologic materials behave as electrical insulators, surface measurements of earth resistivity are controlled by the electrolytic ability of interstitial water. The subsurface distribution of water is controlled by the porosity of the formations. The study area is at Bukit Chondong, Beseri, Perlis. Bukit Chondong is made of sedimentary rock which mostly is sandstone. Bukit Chondong is from uppermost of the Kubang Pasu Formation that represented by a thick unit of grey mudstone interbedded with sandstone. The Kubang Pasu Formation was influenced by shallow marine during the early age. Paleocurrent and fossils traces were found on the mudstone at the study area. The area is suspected to be a Paleozoic aquifer because the sandstone can be a productive aquifer with diffuse flow. The water movement in sandstone is through the fractures and joints. Most of the water stores and transmits in sandstone. The interbedded sandstone and mudstone is one of the aquifer characteristic. Sandstone and mudstone are water-bearing rocks and low-permeable rocks respectively. The data was processed according to the geological information of the study area since there was an outcrop. The study area have low resistivity value which both sandstone and mudstone give less than 800 Ohm-m due to the water content (Sulphide and clay).

Application of geophysical techniques for 3D geohazard mapping to delineate cavities and potential sinkholes in the northern part of Kuala Lumpur, Malaysia.

PubMed

Bakhshipour, Zeinab; Huat, Bujang B K; Ibrahim, Shaharin; Asadi, Afshin; Kura, Nura Umar

2013-01-01

This work describes the application of the electrical resistivity (ER) method to delineating subsurface structures and cavities in Kuala Lumpur Limestone within the Batu Cave area of Selangor Darul Ehsan, Malaysia. In all, 17 ER profiles were measured by using a Wenner electrode configuration with 2 m spacing. The field survey was accompanied by laboratory work, which involves taking resistivity measurements of rock, soil, and water samples taken from the field to obtain the formation factor. The relationship between resistivity and the formation factor and porosity for all the samples was established. The porosity values were plotted and contoured. A 2-dimensional and 3-dimensional representation of the subsurface topography of the area was prepared through use of commercial computer software. The results show the presence of cavities and sinkholes in some parts of the study area. This work could help engineers and environmental managers by providing the information necessary to produce a sustainable management plan in order to prevent catastrophic collapses of structures and other related geohazard problems.

Application of Geophysical Techniques for 3D Geohazard Mapping to Delineate Cavities and Potential Sinkholes in the Northern Part of Kuala Lumpur, Malaysia

PubMed Central

Bakhshipour, Zeinab; Huat, Bujang B. K.; Ibrahim, Shaharin; Asadi, Afshin

2013-01-01

This work describes the application of the electrical resistivity (ER) method to delineating subsurface structures and cavities in Kuala Lumpur Limestone within the Batu Cave area of Selangor Darul Ehsan, Malaysia. In all, 17 ER profiles were measured by using a Wenner electrode configuration with 2 m spacing. The field survey was accompanied by laboratory work, which involves taking resistivity measurements of rock, soil, and water samples taken from the field to obtain the formation factor. The relationship between resistivity and the formation factor and porosity for all the samples was established. The porosity values were plotted and contoured. A 2-dimensional and 3-dimensional representation of the subsurface topography of the area was prepared through use of commercial computer software. The results show the presence of cavities and sinkholes in some parts of the study area. This work could help engineers and environmental managers by providing the information necessary to produce a sustainable management plan in order to prevent catastrophic collapses of structures and other related geohazard problems. PMID:24501583

Nanoscale Controls on CO2-water-rock Interactions in Saline Reservoirs

NASA Astrophysics Data System (ADS)

Deyoreo, J.; Depaolo, D. J.

2009-12-01

It is becoming increasingly widely recognized that geologic sequestration of CO2, when combined with economical means of capture, may be one of the most effective approaches to reducing net CO2 emissions to the atmosphere over the next century. Injection of CO2 into saline geologic formations involves forcing a buoyant, low-viscosity fluid into a more dense, higher viscosity fluid. The difference in wetting properties of the two fluids, their partial miscibility, the fact that CO2 and H2O form an acid, and the heterogeneity of geologic formations combine to make the flow and transport details fascinating but difficult to fully characterize and predict. A major question is whether the flow of CO2 into subsurface formations, the efficiency of pore space filling, and the trapping efficiency can be not only predicted but controlled over the decades of injection that might be associated with the life of a power plant. The major technological gaps to controlling and ultimately sequestering subsurface CO2 can be traced to far-from-equilibrum processes that originate at the molecular and nanoscale, but are expressed as complex emergent behavior at larger scales. Essential knowledge gaps involve the effects of nanoscale confinement on material properties, flow and chemical reactions, the effects of nanoparticles, mineral surface dynamics, and microbiota on mineral dissolution/precipitation and fluid flow, and the dynamics of fluid-fluid and fluid-mineral interfaces. To address these scientific and technical challenges, the Energy Frontier Research Center recently established, involving collaboration between LBNL, ORNL, MIT, UC Berkeley, UC Davis and LLNL, will attempt to bring new approaches to the study of nanoscale phenomena in fluid-rock systems to bear on the problem of CO2 behavior in saline formations. The stated goal is to use molecular, nanoscale, and pore-network scale approaches to control flow, dissolution, and precipitation in deep subsurface rock formations to achieve the efficient filling of pore space while maximizing solubility and mineral trapping and reducing potential leakage. Advanced knowledge of these small-scale processes is an important step toward developing a next-generation predictive capability for reactive transport of CO2-brine systems. The Center involves scientists with expertise in hydrology, geochemistry, materials science, mineralogy, chemistry, microbiology, geophysics, and reactive transport modeling and simulation. This presentation will describe the initial stages of some of the research, which in total involves the use of synchrotron light sources, neutron scattering methods, NanoSIMS, molecular dynamics simulations, thermochemistry, molecular biology, nanotechnology, laboratory scale experiments, and advanced computation applied to flow and reactive transport in heterogeneous porous media. The Center for Nanoscale Control of Geologic CO2 key personnel: Director - D. DePaolo, Co-Director - J. DeYoreo; Research Area Leads - K. Knauss (LBNL), G. Waychunas (LBNL), J. Banfield (UCB/LBNL), A Navrotsky (UC Davis), F.J. Ryerson (LLNL); G. Sposito (UCB/LBNL), T. Tokunaga (LBNL), D. Cole (ORNL), C. Steefel (LBNL), D. Rothman (MIT), S. Pride (LBNL).

Geophysical survey of the proposed Tsenkher impact structure, Gobi Altai, Mongolia

NASA Astrophysics Data System (ADS)

Ormö, Jens; Gomez-Ortiz, David; Komatsu, Goro; Bayaraa, Togookhuu; Tserendug, Shoovdor

2010-03-01

We have performed forward magnetic and gravity modeling of data obtained during the 2007 expedition to the 3.7km in diameter, circular, Tsenkher structure, Mongolia, in order to evaluate the cause of its formation. Extensive occurrences of brecciated rocks, mainly in the form of an ejecta blanket outside the elevated rim of the structure, support an explosive origin (e.g., cosmic impact, explosive volcanism). The host rocks in the area are mainly weakly magnetic, silica-rich sandstones, and siltstones. A near absence of surface exposures of volcanic rocks makes any major volcanic structures (e.g., caldera) unlikely. Likewise, the magnetic models exclude any large, subsurface, intrusive body. This is supported by an 8mGal gravity low over the structure indicating a subsurface low density body. Instead, the best fit is achieved for a bowl-shaped structure with a slight central rise as expected for an impact crater of this size in mainly sedimentary target. The structure can be either root-less (i.e., impact crater) or rooted with a narrow feeder dyke with relatively higher magnetic susceptibility and density (i.e., volcanic maar crater). The geophysical signature, the solitary appearance, the predominantly sedimentary setting, and the comparably large size of the Tsenkher structure favor the impact crater alternative. However, until mineralogical/geochemical evidence for an impact is presented, the maar alternative remains plausible although exceptional as it would make the Tsenkher structure one of the largest in the world in an unusual setting for maar craters.

Microfluidic Investigation of Oil Mobilization in Shale Fracture Networks at Reservoir Conditions

NASA Astrophysics Data System (ADS)

Porter, M. L.; Jimenez-Martinez, J.; Carey, J. W.; Viswanathan, H. S.

2015-12-01

Investigations of pore-scale fluid flow and transport phenomena using engineered micromodels has steadily increased in recent years. In these investigations fluid flow is restricted to two-dimensions allowing for real time visualization and quantification of complex flow and reactive transport behavior, which is difficult to obtain in other experimental systems. One drawback to these studies is the use of engineered materials that do not faithfully represent the rock properties (e.g., porosity, wettability, roughness, etc.) encountered in subsurface formations. In this work, we describe a unique high pressure (up to 1500 psi) and temperature (up to 80 °C) microfluidics experimental system in which we investigate fluid flow and transport in geo-material (e.g., shale, Portland cement, etc.) micromodels. The use of geo-material micromodels allows us to better represent fluid-rock interactions including wettability, chemical reactivity, and nano-scale porosity at conditions representative of natural subsurface environments. Here, we present experimental results in fracture systems with applications to hydrocarbon mobility in hydraulically fractured shale. Complex fracture network patterns are derived from 3D x-ray tomography images of actual fractures created in shale rock cores. We use both shale and glass micromodels, allowing for a detailed comparison between flow phenomena in the different materials. We discuss results from two-phase huff-and-puff experiments involving N2 and n-Decane, as well as three-phase displacement experiments involving supercritical CO2, brine, and n-Decane.

Investigation of the potential for concealed base-metal mineralization at the Drenchwater Creek Zn-Pb-Ag occurrence, northern Alaska, using geology, reconnaissance geochemistry, and airborne electromagnetic geophysics

USGS Publications Warehouse

Graham, Garth E.; Deszcz-Pan, Maria; Abraham, Jared E.; Kelley, Karen D.

2011-01-01

No drilling has taken place at the Drenchwater occurrence, so alternative data sources (for example, geophysics) are especially important in assessing possible indicators of mineralization. Data from the 2005 electromagnetic survey define the geophysical character of the rocks at Drenchwater and, in combination with geological and surface-geochemical data, can aid in assessing the possible shallow (up to about 50 m), subsurface lateral extent of base-metal sulfide accumulations at Drenchwater. A distinct >3-km-long electromagnetic conductive zone (observed in apparent resistivity maps) coincides with, and extends further westward than, mineralized shale outcrops and soils anomalously high in Pb concentrations within the Kuna Formation; this conductive zone may indicate sulfide-rich rock. Models of electrical resistivity with depth, generated from inversion of electromagnetic data, which provide alongflight-line conductivity-depth profiles to between 25 and 50 m below ground surface, show that the shallow subsurface conductive zone occurs in areas of known mineralized outcrops and thins to the east. Broader, more conductive rock along the western ~1 km of the geophysical anomaly does not reach ground surface. These data suggest that the Drenchwater deposit is more extensive than previously thought. The application of inversion modeling also was applied to another smaller geochemical anomaly in the Twistem Creek area. The results are inconclusive, but they suggest that there may be a local conductive zone, possibly due to sulfides.

The Astrobiology of the Subsurface: Caves and Rock Fracture Habitats on Earth, Mars and Beyond

NASA Technical Reports Server (NTRS)

Boston, Penelope J.

2017-01-01

The Astrobiology of the Subsurface: Exploring Cave Habitats on Earth, Mars and Beyond. We are using the spectacular underground landscapes of Earth caves as models for the subsurfaces of other planets. Caves have been detected on the Moon and Mars and are strongly suspected for other bodies in the Solar System including some of the ice covered Ocean Worlds that orbit gas giant planets. The caves we explore and study include many extreme conditions of relevance to planetary astrobiology exploration including high and low temperatures, gas atmospheres poisonous to humans but where exotic microbes can fluorish, highly acidic or salty fluids, heavy metals, and high background radiation levels. Some cave microorganisms eat their way through bedrock, some live in battery acid conditions, some produce unusual biominerals and rare cave formations, and many produce compounds of potential pharmaceutical and industrial significance. We study these unique lifeforms and the physical and chemical biosignatures that they leave behind. Such traces can be used to provide a Field Guide to Unknown Organisms for developing life detection space missions.

Evaluating slope stability prior to road construction

Treesearch

James L. Clayton

1983-01-01

The usefulness of seismic, resistivity, and vegetation surveys for predicting subsurface strength characteristics of granitic rock was evaluated in the Idaho batholith. Rock strength varies inversely with degree of weathering and fracture density. Rocks that have weathered or altered to the point where they contain lays (referred to here as highly weathered rock) are...

Using Muons to Image the Subsurface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonal, Nedra; Cashion, Avery Ted; Cieslewski, Grzegorz

Muons are subatomic particles that can penetrate the earth 's crust several kilometers and may be useful for subsurface characterization . The absorption rate of muons depends on the density of the materials through which they pass. Muons are more sensitive to density variation than other phenomena, including gravity, making them beneficial for subsurface investigation . Measurements of muon flux rate at differing directions provide density variations of the materials between the muon source (cosmic rays and neutrino interactions) and the detector, much like a CAT scan. Currently, muon tomography can resolve features to the sub-meter scale. This work consistsmore » of three parts to address the use of muons for subsurface characterization : 1) assess the use of muon scattering for estimating density differences of common rock types, 2 ) using muon flux to detect a void in rock, 3) measure muon direction by designing a new detector. Results from this project lay the groundwork for future directions in this field. Low-density objects can be detected by muons even when enclosed in high-density material like lead, and even small changes in density (e.g. changes due to fracturing of material) can be detected. Rock density has a linear relationship with muon scattering density per rock volume when this ratio is greater than 0.10 . Limitations on using muon scattering to assess density changes among common rock types have been identified. However, other analysis methods may show improved results for these relatively low density materials. Simulations show that muons can be used to image void space (e.g. tunnels) within rock but experimental results have been ambiguous. Improvements are suggested to improve imaging voids such as tunnels through rocks. Finally, a muon detector has been designed and tested to measure muon direction, which will improve signal-to-noise ratio and help address fundamental questions about the source of upgoing muons .« less

Paleokarst processes in the Eocene limestones of the Pyramids Plateau, Giza, Egypt

NASA Astrophysics Data System (ADS)

El Aref, M. M.; Refai, E.

The Eocene limestones of the Pyramids plateau are characterized by landforms of stepped terraced escarpment and karst ridges with isolated hills. The carbonate country rocks are also dominated by minor surface, surface to subsurface and subsurface solution features associated with karst products. The systematic field observations eludicate the denudation trend of the minor solution features and suggest the origin of the regional landscapes. The lithologic and structural characters of the limestone country rocks comprise the main factors controlling the surface and subsurface karst evolution. The development of the karst features and the associated sediments in the study area provides information on the paleohydrolic, chemical and climatic environments involved in the origin of the karstification.

Geology and ground-water resources of the Rawlins area, Carbon County, Wyoming

USGS Publications Warehouse

Berry, Delmar W.

1960-01-01

The Rawlins area in west-central Carbon County, south-central Wyoming includes approximately 634 square miles of plains and valleys grading into relatively rugged uplifts. The climate is characterized by low precipitation, rapid evaporation, and a wide range of temperature. Railroading and ranching are the principal occupations in the area. The exposed rocks in the area range in age from Precambrian through Recent. The older formations are exposed in the uplifted parts, the oldest being exposed along the apex of the Rawlins uplift. The formations dip sharply away from the anticlines and other uplifts and occur in the subsurface throughout the remainder of the area. The Cambrian rocks (undifferentiated), Madison limestone, Tensleep sandstone, Sun dance formation, Cloverly formation, Frontier formation, and Miocene and Pliocene rocks (undifferentiated) yield water to domestic and stock wells in the area. In the vicinity of the Rawlins uplift, the rocks of Cambrian age, Madison limestone, and Tensleep sandstone yield water to a few public-supply wells. The Cloverly formation yields water to public-supply wells in the Miller Hill and Sage Creek basin area. Wells that tap the Madison limestone, Tensleep sandstone, and Cloverly formation yield water under sufficient artesian pressure to flow at the land surface. The Browns Park formation yields water to springs that supply most of the Rawlins city water and supply water for domestic and stock use. Included on the geologic map are location of wells and test wells, depths to water below land surface, and location of springs. Depths to water range from zero in the unconsolidated deposits along the valley of Sugar Creek at the southern end of the Rawlins uplift to as much as 129 feet below the land surface in the Tertiary sedimentary rocks along the Continental Divide in the southern part of the area. The aquifers are recharged principally by precipitation that falls upon the area, by percolation from streams and ponds, and by movement of ground water from adjacent areas. Water is discharged from the ground-water reservoir by evaporation and transpiration, by seeps and springs, through wells, and by underflow out of the area. Although most water supplies in the area are obtained from springs, some domestic, stock, and public supplies are obtained from drilled wells, many yielding water under artesian pressure, and some flowing. Dissolved solids in the water from several geologic sources, ranging from 181 to 6,660 parts per million (ppm), indicate the varied chemical quality of ground water in the Rawlins area. Water from the Cambrian rocks, Tensleep sandstone, Cloverly formation, Frontier formation, Browns Park formation, and Miocene and Pliocene rocks is generally suitable for domestic and stock use. However, water yielded to the only well sampled in the lower part of the Frontier formation contained a high concentration of fluoride. Water from the rocks mentioned above contains less than 1,000 ppm of dissolved solids but in some places may contain iron in troublesome amounts. Water from the Madison limestone and Tensleep sandstone combined, Permian rocks, and Sundance formation contains more than 1,000 ppm of dissolved solids. Water in the Sundance, Cloverly, and Frontier :formations is very soft. More ground water can be obtained in the Rawlins area than is now being used. Many springs are undeveloped, and water can be obtained from additional wells without unduly lowering ground-water levels.

The Role of Subsurface Water in Carving Hesperian Amphitheater-Headed Valleys

NASA Astrophysics Data System (ADS)

Lapotre, M. G. A.; Lamb, M. P.

2017-12-01

Groundwater sapping may play a role in valley formation in rare cases on Earth, typically in sand or weakly cemented sandstones. Small-scale valleys resulting from groundwater seepage in loose sand typically have amphitheater-shaped canyon heads with roughly uniform widths. By analogy to terrestrial sapping valleys, Hesperian-aged amphitheater canyons on Mars have been interpreted to result from groundwater sapping, with implications for subsurface and surface water flows on ancient Mars. However, other studies suggest that martian amphitheater canyons carved in fractured rock may instead result from large overland floods, by analogy to dry cataracts in scabland terrains in the northwestern U.S. Understanding the formation of bedrock canyons is critical to our understanding of liquid water reservoirs on ancient Mars. Can groundwater sapping carve canyons in substrates other than sand? There is currently no model to predict the necessary conditions for groundwater to carve canyons in substrates ranging from loose sediment of various sizes to competent rock. To bridge this knowledge gap, we formulate a theoretical model coupling equations of groundwater flow and sediment transport that can be applied to a wide range of substrates. The model is used to infer whether groundwater sapping could have carved canyons in the absence of overland flows, and requires limited inputs that are measureable in the field or from orbital images. Model results show that sapping erosion is capable of forming canyons, but only in loose well-sorted sand. Coarser sediment is more permeable, but more difficult to transport. Finer sediment is more easily transported, but lower permeability precludes the necessary seepage discharge. Finally, fractured rock is highly permeable, but seepage discharges are far below those required to transport typical talus boulders. Using orbiter-based lithological constraints, we conclude that canyons near Echus Chasma are carved into bedrock and therefore required high-discharge overland flow during formation. These results have implications for Hesperian hydrology; while water volumes to carve sapping versus flood canyons need not be significantly different, erosion rates are orders of magnitude faster in the flood scenario, implying brief periods of abundant surface water on Hesperian Mars.

Up-Scaling Geochemical Reaction Rates for Carbon Dioxide (CO2) in Deep Saline Aquifers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peters, Catherine A

2013-02-28

Geochemical reactions in deep subsurface environments are complicated by the consolidated nature and mineralogical complexity of sedimentary rocks. Understanding the kinetics of these reactions is critical to our ability to make long-term predictions about subsurface processes such as pH buffering, alteration in rock structure, permeability changes, and formation of secondary precipitates. In this project, we used a combination of experiments and numerical simulation to bridge the gap between our knowledge of these reactions at the lab scale and rates that are meaningful for modeling reactive transport at core scales. The focus is on acid-driven mineral dissolution, which is specifically relevantmore » in the context of CO2-water-rock interactions in geological sequestration of carbon dioxide. The project led to major findings in three areas. First, we modeled reactive transport in pore-network systems to investigate scaling effects in geochemical reaction rates. We found significant scaling effects when CO2 concentrations are high and reaction rates are fast. These findings indicate that the increased acidity associated with geological sequestration can generate conditions for which proper scaling tools are yet to be developed. Second, we used mathematical modeling to investigate the extent to which SO2, if co-injected with CO2, would acidify formation brines. We found that there exist realistic conditions in which the impact on brine acidity will be limited due to diffusion rate-limited SO2 dissolution from the CO2 phase, and the subsequent pH shift may also be limited by the lack of availability of oxidants to produce sulfuric acid. Third, for three Viking sandstones (Alberta sedimentary basin, Canada), we employed backscattered electron microscopy and energy dispersive X-ray spectroscopy to statistically characterize mineral contact with pore space. We determined that for reactive minerals in sedimentary consolidated rocks, abundance alone is not a good predictor of mineral accessible surface area, and should not be used in reactive transport modeling. Our work showed that reaction rates would be overestimated by three to five times.« less

3D mapping of buried rocks by the GPR WISDOM/ExoMars 2020

NASA Astrophysics Data System (ADS)

Herve, Yann; Ciarletti, Valerie; Le Gall, Alice; Quantin, Cathy; Guiffaut, Christophe; Plettemeier, Dirk

2017-04-01

The main objective of ExoMars 2020 is to search for signs of past and/or present life on Mars. Because these signs may be beneath the inhospitable surface of Mars, the ExoMars Rover has on board a suite of instruments aiming at characterizing the subsurface. In particular, the Rover payload includes WISDOM (Water Ice Subsurface Deposits Observation on Mars), a polarimetric ground penetrating radar designed to investigate the shallow subsurface. WISDOM is able to probe down to a depth of few meters with a resolution of few centimeters; its main objective is to provide insights into the geological context of the investigated Martian sites and to determine the most promising location to collect samples for the ExoMars drill. In this paper, we demonstrate the ability of WISDOM to locate buried rocks and to estimate their size distribution. Indeed, the rock distribution is related to the geological processes at play in the past or currently and thus provides clues to understand the geological context of the investigated site. Rocks also represent a hazard for drilling operations that WISDOM is to guide. We use a 3D FDTD code called TEMSI-FD (which takes into account the radiation pattern of the antenna system) to simulate WISDOM operations on a realistic (both in terms of dielectric properties and structure) ground. More specifically, our geoelectrical models of the Martian subsurface take into account realistic values of the complex permittivity relying on published measurements performed in laboratory on Martian analogues. Further, different distributions of buried rocks are considered based on the size-frequency distribution observed at the Mars Pathfinder landing site and on Oxia Planum, the landing site currently selected for ExoMars 2020. We will describe the algorithm we developed to automatically detect the signature of the buried rocks on radargrams. The radargrams are obtained simulating WISDOM operations along parallel and perpendicular profiles as planned for the ExoMars mission. Our ultimate goal is to show that WISDOM observations can be used to build a 3D map of the subsurface. We will also present experimental data obtained with a prototype of WISDOM to test our method.

3D Seismic Imaging over a Potential Collapse Structure

NASA Astrophysics Data System (ADS)

Gritto, Roland; O'Connell, Daniel; Elobaid Elnaiem, Ali; Mohamed, Fathelrahman; Sadooni, Fadhil

2016-04-01

The Middle-East has seen a recent boom in construction including the planning and development of complete new sub-sections of metropolitan areas. Before planning and construction can commence, however, the development areas need to be investigated to determine their suitability for the planned project. Subsurface parameters such as the type of material (soil/rock), thickness of top soil or rock layers, depth and elastic parameters of basement, for example, comprise important information needed before a decision concerning the suitability of the site for construction can be made. A similar problem arises in environmental impact studies, when subsurface parameters are needed to assess the geological heterogeneity of the subsurface. Environmental impact studies are typically required for each construction project, particularly for the scale of the aforementioned building boom in the Middle East. The current study was conducted in Qatar at the location of a future highway interchange to evaluate a suite of 3D seismic techniques in their effectiveness to interrogate the subsurface for the presence of karst-like collapse structures. The survey comprised an area of approximately 10,000 m2 and consisted of 550 source- and 192 receiver locations. The seismic source was an accelerated weight drop while the geophones consisted of 3-component 10 Hz velocity sensors. At present, we analyzed over 100,000 P-wave phase arrivals and performed high-resolution 3-D tomographic imaging of the shallow subsurface. Furthermore, dispersion analysis of recorded surface waves will be performed to obtain S-wave velocity profiles of the subsurface. Both results, in conjunction with density estimates, will be utilized to determine the elastic moduli of the subsurface rock layers.

Desert pavement study at Amboy, California

NASA Technical Reports Server (NTRS)

Williams, S.; Greeley, R.

1984-01-01

Desert pavement is a general term describing a surface that typically consists of a thin layer of cm-sized rock fragments set on top of a layer of finer material in which no fragments are found. An understanding of desert pavement is important to planetary geology because they may play a major role in the formation and visibility of various aeolian features such as wind streaks, which are important on Mars and may be important on Venus. A field study was conducted in Amboy, California to determine the formation mechanism of desert pavements. The probable sequence of events for the formation and evolution of a typical desert pavement surface, based on this experiment and the work of others, is as follows. Starting with a layer of surface material consisting of both fine particles and rock fragments, aeolian deflation will rapidly erode the surface until an armored lag is developed, after which aeolian processes become less important. The concentration of fragments then slowly increases as new fragments are brought to the surface from the subsurface and as fragments move downslope by sheet wash. Sheet wash would be responsible for removing very fine particles from the surface and for moving the fragments relative to one another, forming interlocks.

Multiphase, multicomponent simulations and experiments of reactive flow, relevant for combining geologic CO2 sequestration with geothermal energy capture

NASA Astrophysics Data System (ADS)

Saar, Martin O.

2011-11-01

Understanding the fluid dynamics of supercritical carbon dioxide (CO2) in brine- filled porous media is important for predictions of CO2 flow and brine displacement during geologic CO2 sequestration and during geothermal energy capture using sequestered CO2 as the subsurface heat extraction fluid. We investigate multiphase fluid flow in porous media employing particle image velocimetry experiments and lattice-Boltzmann fluid flow simulations at the pore scale. In particular, we are interested in the motion of a drop (representing a CO2 bubble) through an orifice in a plate, representing a simplified porous medium. In addition, we study single-phase/multicomponent reactive transport experimentally by injecting water with dissolved CO2 into rocks/sediments typically considered for CO2 sequestration to investigate how resultant fluid-mineral reactions modify permeability fields. Finally, we investigate numerically subsurface CO2 and heat transport at the geologic formation scale.

Feeding a subsurface biosphere: radiolysis and abiogenic energy sources

NASA Astrophysics Data System (ADS)

Onstott, T.

Noble gas analyses of ground water collected from the deep, fractured, basaltic andesite and quartzite Archean strata in South Africa suggest subsurface residence times ranging from tens to hundreds of millions of years. Hydraulically isolated compartments of highly saline water contain hundreds of μM concentrations of gas comprised primarily of C1-4 hydrocarbons, H2 and He, with minor Ar and N .2 Carbon and hydrogen isotopic analyses of the hydrocarbons suggest an abiogenic origin com atible with surface catalysed reductive assimilation (i.e. Fischer-Tropschp synthesis). H2 and He data suggest that the H2 is generated by subsurface radiolysis of water. One sample of a saline, isolated water/gas pocket agrees exactly with that predicted by radioactive decay of U, Th, K in the host rock and indicates a subsurface H2 production rate of 0.1 to 1 nM/yr. Other samples yielded less H2 than predicted and require a sink for this H2 . Possible sinks include microbial H2 oxidation and abiotic formation of hydrocarbons at rates slightly less than the H2 production rate. Highly diffusive H2 is essential for life in deep subsurface environments where only trace amounts of organic carbon exist. Lithoautotrophic microbes can acquire energy from the redox reactions involving H2 with other electron acceptors (Fe3 +, SO4 2 - or CO2 ), to synthesis organic carbon and can be fully independent of solar-driven photosynthesis. The microbial abundance in many of these ground water samples, however, is below our detection limit (<5000 cells/ml). This contrasts with shallow sedimentary aquifers where H2 levels of tens of nM are regulated by the coexistence of autotrophs/lithotrophs and heterotrophs for maximum efficiency of H2 utilization. The excessive H2 found in deep crustal environments implies that these microbial ecosystems are electron-acceptor and or substrate limited. The oxidants generated by water radiolysis interact with the reduced solid phases in the rock matrix, e.g. pyrite, producing potential electron acceptors, e.g. Fe3 +, that may be readily available for consumption by microbial communities than H . Nitrogen doesn't appear to be2 limited, because ammonia concentrations range upwards to tens of μM, but its origin remains a mystery. The unused H2 , CH4 and He continue to migrate upward to shallow aquifers. Microbial H2 oxidation may dominate over Fischer-Tropsch reactions in crustal environments where formation temperatures are <120o C; and vice versa for deeper crustal environments. This H2 cycle should be present on extraterrestrial bodies, producing potential chemical energy and crustal scale diffusive fluxes from the interaction subsurface ice/water and radiogenic decay.

Reconnaissance of geology and water resources along the north flank of the Sweet Grass Hills, north-central Montana

USGS Publications Warehouse

Tuck, L.K.

1993-01-01

Mississippian through Holocene rocks crop out in the area. Emplaced Tertiary igneous rocks have caused structural deformation. Aquifers are Holocene alluvium, Quaternary interstratified sand and gravel, and Upper Cretaceous Judith River Formation and Virgelle Sandstone Member of Eagle Sandstone. Recharge to each aquifer is through combinations of infiltration of precipitation, streamflow, irrigation return flow, stored surface water, and subsurface inflow. Discharge is through combinations of seepage to streams, withdrawals from wells, flow of springs and seeps, evapotranspiration, and subsurface outflow. Water in alluvium flows sub- parallel to stream channels. One water sample had a dissolved-solids concentration of 439 milligrams per liter. Water in the interstratified sand and gravel generally moves northward. Transmissivity was estimated at 900 feet squared per day. Dissolved- solids concentration ranged from 154 to 1,600 milligrams per liter. Water quality is least feasible for irrigation, marginal for domestic use, and generally suitable for livestock. Water in the Judith River Formation probably flows northeast and southeast. One water sample had a dissolved-solids concentration of 855 milligrams per liter. Water in the Virgelle Sandstone Member generally flows north. Transmissivity ranges from 200 to 3,700 feet squared per day. Dissolved-solids concentration ranged from 213 to 1,360 milligrams per liter. Water quality near outcrops is mostly adequate for domestic and livestock use and marginal for irrigation, but deteriorates downgradient. Unknown perennial yields and water quality could limit development of this resource. Miners Coulee, Breed Creek, and Bear Gulch flow intermittently. Dissolved-solids concentration ranged from 241 to 774 milligrams per liter.

Stratigraphy and tectonic history of the Tucson Basin, Pima County, Arizona, based on the Exxon state (32)-1 well

USGS Publications Warehouse

Houser, Brenda B.; Peters, Lisa; Esser, Richard P.; Gettings, Mark E.

2004-01-01

The Tucson Basin is a relatively large late Cenozoic extensional basin developed in the upper plate of the Catalina detachment fault in the southern Basin and Range Province, southeastern Arizona. In 1972, Exxon Company, U.S.A., drilled an exploration well (Exxon State (32)-1) near the center of the Tucson Basin that penetrated 3,658 m (12,001 ft) of sedimentary and volcanic rocks above granitoid basement. Detailed study of cuttings and geophysical logs of the Exxon State well has led to revision of the previously reported subsurface stratigraphy for the basin and provided new insight into its depositional and tectonic history. There is evidence that detachment faulting and uplift of the adjacent Catalina core complex on the north have affected the subsurface geometry of the basin. The gravity anomaly map of the Tucson Basin indicates that the locations of subbasins along the north-trending axis of the main basin coincide with the intersection of this axis with west-southwest projections of synforms in the adjacent core complex. In other words, the subbasins overlie synforms and the ridges between subbasins overlie antiforms. The Exxon State well was drilled near the center of one of the subbasins. The Exxon well was drilled to a total depth of 3,827 m (12,556 ft), and penetrated the following stratigraphic section: Pleistocene(?) to middle(?) Miocene upper basin-fill sedimentary rocks (0-908 m [0-2,980 ft]) lower basin-fill sedimentary rocks (908-1,880 m [2,980-6,170 ft]) lower Miocene and upper Oligocene Pantano Formation (1,880-2,516 m [6,170-8,256 ft]) upper Oligocene to Paleocene(?) volcanic and sedimentary rocks (2,516-3,056 m [8,256-10,026 ft]) Lower Cretaceous to Upper Jurassic Bisbee Group (3,056-3,658 m [10,026-12,001 ft]) pre-Late Jurassic granitoid plutonic rock (3,658-3,827 m [12,001- 12,556 ft]). Stratigraphy and Tectonic History of the Tucson Basin, Pima County, Arizona, Based on the Exxon State (32)-1 Well The 1,880 m (6,170 ft) of basin-fill sedimentary rocks consist of alluvial-fan, alluvial-plain, and playa facies. The uppermost unit, a 341-m-thick (1,120-ft) lower Pleistocene and upper Pliocene alluvial-fan deposit (named the Cienega Creek fan in this study), is an important aquifer in the Tucson basin. The facies change at the base of the alluvial fan may prove to be recognizable in well data throughout much of the basin. The well data show that a sharp boundary at 908 m (2,980 ft) separates relatively unconsolidated and undeformed upper basin fill from denser, significantly faulted lower basin fill, indicating that there were two stages of basin filling in the Tucson basin as in other basins of the region. The two stages apparently occurred during times of differing tectonic style in the region. In the Tucson area the Pantano Formation, which contains an andesite flow dated at about 25 Ma, fills a syntectonic basin in the hanging wall of the Catalina detachment fault, reflecting middle Tertiary extension on the fault. The formation in the well is 636 m thick (2,086 ft) and consists of alluvial-fan, playa, and lacustrine sedimentary facies, a lava flow, and rock- avalanche deposits. Analysis of the geophysical logs indicates that a K-Ar date of 23.4 Ma reported previously for the Pantano interval of the well was obtained on selected cuttings collected from a rock-avalanche deposit near the base of the unit and, thus, does not date the Pantano Formation. The middle Tertiary volcanic and sedimentary rocks have an aggregate thickness of 540 m (1,770 ft). We obtained a new 40Ar/ 39Ar age of 26.91+0.18 Ma on biotite sampled at a depth of 2,584-2,609 m (8,478-8,560 ft) from a 169-m-thick (554-ft) silicic tuff in this interval. The volcanic rocks probably correlate with other middle Tertiary volcanic rocks of the area, and the sedimentary rocks may correlate with the Cloudburst and Mineta Formations exposed on the flanks of the San Pedro Basin to the northeast. The Bisbee Group in the Exxon well is 602 m (1,975 f

Apparently spontaneous fracture of a granitic exfoliation dome: observations and monitoring

NASA Astrophysics Data System (ADS)

Collins, B. D.; Stock, G. M.; Eppes, M. C.; Lewis, S. W.; Corbett, S.; Smith, J. B.

2016-12-01

Exfoliation sheet formation has attracted scientific attention for more than two centuries. Although a number of theories have been proposed, firm understanding of the cause of exfoliation has proved elusive, partly because observations of their formation are scarce. The 2014-2016 spontaneous exfoliation of Twain Harte Dome, located in the western foothills of California's Sierra Nevada Mesozoic granitic batholith, provides an unprecedented opportunity to study this phenomenon. Understanding such events can offer direct insight into similar exfoliating environments where spontaneous rock fracturing generates related geohazards such as rock falls. Twain Harte Dome fractured energetically on at least 5 occasions in August and September 2014, with slabs of rock thrust into the air 40 cm in a few seconds time and surficial fracture of rock occurring over a total area of 2,800 m2. Several of these events were witnessed first-hand and recorded by video. Additional (but non-energetic) cracking occurred during August 2015, followed by another energetic fracturing event in June 2016 over a much smaller (16 m2) area that again sent granite slabs airborne. No previous spontaneous exfoliation had been recorded here over the past 90 years and no obvious trigger (e.g., earthquake) occurred prior to the recent events. Using high-resolution topographic and fracture mapping, acoustic emission monitoring, and environmental monitoring, we show that these fracture events are correlated with hot summer periods - an indication that thermal stresses likely have an important role in causing exfoliation. Surface crackmeter, and subsurface borehole extensometer and rock bolt force measurements strengthen this relationship, with stresses and deformations spiking during hot summer afternoons. Our instrumentation data captured one of the exfoliation events and show that cumulative stress and deformation increases may have acted as precursor signals to the apparently spontaneous rock exfoliation.

High resolution study of petroleum source rock variation, Lower Cretaceous (Hauterivian and Barremian) of Mikkelsen Bay, North Slope, Alaska

USGS Publications Warehouse

Keller, Margaret A.; Macquaker, Joe H.S.; Lillis, Paul G.

2001-01-01

Open File Report 01-480 was designed as a large format poster for the Annual Meeting of the American Association of Petroleum Geologists and the Society for Sedimentary Geology in Denver Colorado in June 2001. It is reproduced here in digital format to make widely available some unique images of mudstones. The images include description, interpretation, and Rock-Eval data that resulted from a high-resolution study of petroleum source rock variation of the Lower Cretaceous succession of the Mobil-Phillips Mikkelsen Bay State #1 well on the North Slope of Alaska. Our mudstone samples with Rock-Eval data plus color images are significant because they come from one of the few continuously cored and complete intervals of the Lower Cretaceous succession on the North Slope. This succession, which is rarely preserved in outcrop and very rarely cored in the subsurface, is considered to include important petroleum source rocks that have not previously been described nor explained Another reason these images are unique is that the lithofacies variability within mudstone dominated successions is relatively poorly known in comparison with that observed in coarser clastic and carbonate successions. They are also among the first published scans of thin sections of mudstone, and are of excellent quality because the sections are well made, cut perpendicular to bedding, and unusually thin, 20 microns. For each of 15 samples, we show a thin section scan (cm scale) and an optical photomicrograph (mm scale) that illustrates the variability present. Several backscattered SEM images are also shown. Rock-Eval data for the samples can be compared with the textures and mineralogy present by correlating sample numbers and core depth.

Micromechanical Tests and Geochemical Modeling to Evaluate Evolution of Rock Alteration by CO2-Water Mixtures

NASA Astrophysics Data System (ADS)

Aman, M.; Sun, Y.; Ilgen, A.; Espinoza, N.

2015-12-01

Injection of large volumes of CO2 into geologic formations can help reduce the atmospheric CO2 concentration and lower the impact of burning fossil fuels. However, the injection of CO2 into the subsurface shifts the chemical equilibrium between the mineral assemblage and the pore fluid. This shift will situationally facilitate dissolution and reprecipitation of mineral phases, in particular intergranular cements, and can potentially affect the long term mechanical stability of the host formation. The study of these coupled chemical-mechanical reservoir rock responses can help identify and control unexpected emergent behavior associated with geological CO2 storage.Experiments show that micro-mechanical methods are useful in capturing a variety of mechanical parameters, including Young's modulus, hardness and fracture toughness. In particular, micro-mechanical measurements are well-suited for examining thin altered layers on the surfaces of rock specimens, as well as capturing variability on the scale of lithofacies. We performed indentation and scratching tests on sandstone and siltstone rocks altered in natural CO2-brine environments, as well as on analogous samples altered under high pressure, temperature, and dissolved CO2 conditions in a controlled laboratory experiment. We performed geochemical modeling to support the experimental observations, in particular to gain the insight into mineral dissolution/precipitation as a result of the rock-water-CO2reactions. The comparison of scratch measurements performed on specimens both unaltered and altered by CO2 over geologic time scales results in statistically different values for fracture toughness and scratch hardness, indicating that long term exposure to CO2 caused mechanical degradation of the reservoir rock. Geochemical modeling indicates that major geochemical change caused by CO2 invasion of Entrada sandstone is dissolution of hematite cement, and its replacement with siderite and dolomite during the alteration process.

Sources of Hydrogen as Food for Deep Microbial Communities

NASA Technical Reports Server (NTRS)

Freund, Friedemann; Fonda, Mark (Technical Monitor)

1998-01-01

To survive in deep subsurface environments autolithotrophic microbial communities require a sustainable food supply. One possible source is H2 which forms when H2O reacts with ferrous iron at rock surfaces or mineral grain boundaries to produce H2 plus ferric iron. The amount of H2 that can be supplied in this way, however, is relatively small and may not last for more than a few hundred or thousand years. A much larger reservoir of H2 exists in the rocks, inside mineral grains, arising from an as yet little-known redox conversion that affects OH- in nominally anhydrous minerals. These OH- represent small amounts of "water" that become incorporated during crystallization in H2O-laden environments. A corollary of the H2 formation from OH- is the formation of peroxy, an oxidized form of oxygen. While the peroxy become part of the mineral structure, the H2 molecules are diffusively mobile and can escape from within the mineral grains, entering the intergranular space. Assuming cautiously realistic number densities of OH- undergoing the in situ redox conversion to H2 plus peroxy, a 10 km deep rock column is expected to contain enough H2 to allow for a constant degassing rate of 50-100 nmole H2 per day per sq cm over 30 million years.

10 CFR 60.141 - Confirmation of geotechnical and design parameters.

Code of Federal Regulations, 2011 CFR

2011-01-01

... deformations and displacement, changes in rock stress and strain, rate and location of water inflow into subsurface areas, changes in groundwater conditions, rock pore water pressures including those along...

10 CFR 60.141 - Confirmation of geotechnical and design parameters.

Code of Federal Regulations, 2010 CFR

2010-01-01

... deformations and displacement, changes in rock stress and strain, rate and location of water inflow into subsurface areas, changes in groundwater conditions, rock pore water pressures including those along...

Estimate of subsurface formation temperature in the Tarim basin, northwest China

NASA Astrophysics Data System (ADS)

Liu, Shaowen; Lei, Xiao; Feng, Changge; Hao, Chunyan

2015-04-01

Subsurface formation temperature in the Tarim basin, the largest sedimentary basin in China, is significant for its hydrocarbon generation, preservation and geothermal energy potential assessment, but till now is not well understood, due to poor data coverage and a lack of highly accurate temperature data. Here, we combined recently acquired steady-state temperature logging data, drill stem test temperature data and measured rock thermal properties, to investigate the geothermal regime, and estimate the formation temperature at specific depths in the range 1000~5000 m in this basin. Results show that the heat flow of the Tarim basin ranges between 26.2 and 66.1 mW/m2, with a mean of 42.5±7.6 mW/m2; geothermal gradient at the depth of 3000 m varies from 14.9 to 30.2 °C/km, with a mean of 20.7±2.9 °C/km. Formation temperature at the depth of 1000 m is estimated to be between 29 °C and 41°C, with a mean of 35°C; whilst the temperature at 2000 m ranges from 46~71°C with an average of 59°C; 63~100°C is for that at the depth of 3000 m, and the mean is 82°C; the temperature at 4000 m varies from 80 to 130°C, with a mean of 105°C; 97~160°C is for the temperature at 5000 m depth. In addition, the general pattern of the subsurface formation temperatures at different depths is basically similar and is characterized by high temperatures in the uplift areas and low temperatures in the sags. Basement structure and lateral variations in thermal properties account for this pattern of the geo-temperature field in the Tarim basin.

Pitted rock surfaces on Mars: A mechanism of formation by transient melting of snow and ice

NASA Astrophysics Data System (ADS)

Head, James W.; Kreslavsky, Mikhail A.; Marchant, David R.

2011-09-01

Pits in rocks on the surface of Mars have been observed at several locations. Similar pits are observed in rocks in the Mars-like hyperarid, hypothermal stable upland zone of the Antarctic Dry Valleys; these form by very localized chemical weathering due to transient melting of small amounts of snow on dark dolerite boulders preferentially heated above the melting point of water by sunlight. We examine the conditions under which a similar process might explain the pitted rocks seen on the surface of Mars (rock surface temperatures above the melting point; atmospheric pressure exceeding the triple point pressure of H2O; an available source of solid water to melt). We find that on Mars today each of these conditions is met locally and regionally, but that they do not occur together in such a way as to meet the stringent requirements for this process to operate. In the geological past, however, conditions favoring this process are highly likely to have been met. For example, increases in atmospheric water vapor content (due, for example, to the loss of the south perennial polar CO2 cap) could favor the deposition of snow, which if collected on rocks heated to above the melting temperature during favorable conditions (e.g., perihelion), could cause melting and the type of locally enhanced chemical weathering that can cause pits. Even when these conditions are met, however, the variation in heating of different rock facets under Martian conditions means that different parts of the rock may weather at different times, consistent with the very low weathering rates observed on Mars. Furthermore, as is the case in the stable upland zone of the Antarctic Dry Valleys, pit formation by transient melting of small amounts of snow readily occurs in the absence of subsurface active layer cryoturbation.

Regional stratigraphic framework of the Lisburne Group of ANWR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watts, K.F.; Carlson, R.C.; Harris, A.G.

1995-05-01

The Carboniferous Lisburne Group, a major carbonate platform succession, is widely exposed in the Brooks Range and forms an extensive hydrocarbon target in the subsurface of the North Slope of Alaska. Gradationally beneath carbonates of the Lisburne Group, terrigenous sediments of the Mississippian Endicott Group (conglomerate and sandstone of the Kekiktuk Formation overlain by the Kayak Shale) were derived from local and northern (Ellesmerian) source areas. Locally, at the Endicott-Lisburne transition, sandy limestones of the Itkilyariak Formation record another phase of siliciclastic influx that lies above and/or is a lateral equivalent of the Kayak Shale and Lisburne Group in areasmore » adjacent to paleotopographic highs. This siliciclastic to carbonate transition represents a major transgressive succession that onlaps northward over the sub-Mississippian unconformity, a regional angular unconformity and sequence boundary in northern Alaska. The age and nature of onlap depend upon the paleotopography of the underlying sub-Mississippian rocks and regional passive margin subsidence. The Lisburne Group is a thick succession of carbonate rocks subdivided into the Alapah Limestone and overlying Wahoo Limestone, both having informal members.« less

Hydrogeochemical Investigation of Recharge Pathways to Intermediate and Regional Groundwater in Canon de Valle and Technical Area 16, Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brady, Brendan W.

In aquifers consisting of fractured or porous igneous rocks, as well as conglomerate and sandstone products of volcanic formations, silicate minerals actively dissolve and precipitate (Eby, 2004; Eriksson, 1985; Drever, 1982). Dissolution of hydrated volcanic glass is also known to influence the character of groundwater to which it is exposed (White et al., 1980). Hydrochemical evolution, within saturated zones of volcanic formations, is modeled here as a means to resolve the sources feeding a perched groundwater zone. By observation of solute mass balances in groundwater, together with rock chemistry, this study characterizes the chemical weathering processes active along recharge pathwaysmore » in a mountain front system. Inverse mass balance modeling, which accounts for mass fluxes between solid phases and solution, is used to contrive sets of quantitative reactions that explain chemical variability of water between sampling points. Model results are used, together with chloride mass balance estimation, to evaluate subsurface mixing scenarios generated by further modeling. Final model simulations estimate contributions of mountain block and local recharge to various contaminated zones.« less

Subsurface stratigraphy and oil fields in the Salem Limestone and associated rocks in Indiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, S.J.; Becker, L.E.

An area of 11 counties in southwestern Indiana was studied because (1) the subsurface geology of the Salem Limestone and associated rocks in the area contained numerous correlation discrepancies; (2) it was the locus of recent oil exploration and oil discoveries in these rocks; (3) the last subsurface study of this rock section was made in 1957; and (4) since that time, subsurface data from newly drilled petroleum-test wells have increased a hundredfold. Because of their abundance, geophysical logs were used extensively for correlation. Drill cuttings, where available, were also used in studying the rock units. The upper boundary ofmore » the Salem was based on geophysical-log correlations as supported by available drill cuttings. The lower boundary of the Salem was based on drill cuttings. Commercial oil is produced from porous calcarenite zones in the St. Louis and Salem Limestones and from coarsely crystalline limestone in the Harrodsburg Limestone. The lower part of the St. Louis Limestone yields oil from a porous carbonate rock that resembles Salem calcarenite and that we have formally named the Sission Member in the St. Louis. The Salem calcarenite facies ranges in thickness from a low of 10 percent of the total Salem in the southern part of the study area to a high of 80 percent in the northern part. Oil is produced from porous zones in the calcarenite. Oil production from the St. Louis, Salem, and Harrodsburg Limestones in Indiana amounted to 8,880,078 barrels as of December 31, 1978. Production in 1977 was 1,534,320 barrels, and production in 1978 was 1,157,450 barrels. About 80 percent of the 1977 and 1978 production came from Union-Bowman Consolidated and Sisson Fields in Gibson, Knox, and Pike counties and the Owensville North Consolidated and Mt. Carmel Consolidated Fields in Gibson County. 15 figures, 3 tables.« less

A Subsurface Soil Composition and Physical Properties Experiment to Address Mars Regolith Stratigraphy

NASA Technical Reports Server (NTRS)

Richter, L.; Sims, M.; Economou, T.; Stoker, C.; Wright, I.; Tokano, T.

2004-01-01

Previous in-situ measurements of soil-like materials on the surface of Mars, in particular during the on-going Mars Exploration Rover missions, have shown complex relationships between composition, exposure to the surface environment, texture, and local rocks. In particular, a diversity in both compositional and physical properties could be established that is interpreted to be diagnostic of the complex geologic history of the martian surface layer. Physical and chemical properties vary laterally and vertically, providing insight into the composition of rocks from which soils derive, and environmental conditions that led to soil formation. They are central to understanding whether habitable environments existed on Mars in the distant past. An instrument the Mole for Soil Compositional Studies and Sampling (MOCSS) - is proposed to allow repeated access to subsurface regolith on Mars to depths of up to 1.5 meters for in-situ measurements of elemental composition and of physical and thermophysical properties, as well as for subsurface sample acquisition. MOCSS is based on the compact PLUTO (PLanetary Underground TOol) Mole system developed for the Beagle 2 lander and incorporates a small X-ray fluorescence spectrometer within the Mole which is a new development. Overall MOCSS mass is approximately 1.4 kilograms. Taken together, the MOCSS science data support to decipher the geologic history at the landing site as compositional and textural stratigraphy if they exist - can be detected at a number of places if the MOCSS were accommodated on a rover such as MSL. Based on uncovered stratigraphy, the regional sequence of depositional and erosional styles can be constrained which has an impact on understanding the ancient history of the Martian near-surface layer, considering estimates of Mars soil production rates of 0.5... 1.0 meters per billion years on the one hand and Mole subsurface access capability of approximately 1.5 meters. An overview of the MOCSS, XRS instrument accomodation and the impact that these instruments have on Mars science is discussed.

Geomicrobiology and Metagenomics of Terrestrial Deep Subsurface Microbiomes.

PubMed

Itävaara, M; Salavirta, H; Marjamaa, K; Ruskeeniemi, T

2016-01-01

Fractures in the deep subsurface of Earth's crust are inhabited by diverse microbial communities that participate in biogeochemical cycles of the Earth. Life on Earth, which arose c. 3.5-4.0 billion years ago, reaches down at least 5 km in the crust. Deep mines, caves, and boreholes have provided scientists with opportunities to sample deep subsurface microbiomes and to obtain information on the species diversity and functions. A wide variety of bacteria, archaea, eukaryotes, and viruses are now known to reside in the crust, but their functions are still largely unknown. The crust at different depths has varying geological composition and hosts endemic microbiomes accordingly. The diversity is driven by geological formations and gases evolving from deeper depths. Cooperation among different species is still mostly unexplored, but viruses are known to restrict density of bacterial and archaeal populations. Due to the complex growth requirements of the deep subsurface microbiomes, the new knowledge about their diversity and functions is mostly obtained by molecular methods, eg, meta'omics'. Geomicrobiology is a multidisciplinary research area combining disciplines from geology, mineralogy, geochemistry, and microbiology. Geomicrobiology is concerned with the interaction of microorganisms and geological processes. At the surface of mineralogical or rock surfaces, geomicrobial processes occur mainly under aerobic conditions. In the deep subsurface, however, the environmental conditions are reducing and anaerobic. The present chapter describes the world of microbiomes in deep terrestrial geological environments as well as metagenomic and metatranscriptomic methods suitable for studies of these enigmatic communities. Copyright © 2016 Elsevier Inc. All rights reserved.

Field investigation of the drift shadow

USGS Publications Warehouse

Su, G.W.; Kneafsey, T.J.; Ghezzehei, T.A.; Cook, P.J.; Marshall, B.D.

2006-01-01

The "Drift Shadow" is defined as the relatively drier region that forms below subsurface cavities or drifts in unsaturated rock. Its existence has been predicted through analytical and numerical models of unsaturated flow. However, these theoretical predictions have not been demonstrated empirically to date. In this project we plan to test the drift shadow concept through field investigations and compare our observations to simulations. Based on modeling studies we have an identified a suitable site to perform the study at an inactive mine in a sandstone formation. Pretest modeling studies and preliminary characterization of the site are being used to develop the field scale tests.

Simulation of Mechanical Processes in Gas Storage Caverns for Short-Term Energy Storage

NASA Astrophysics Data System (ADS)

Böttcher, Norbert; Nagel, Thomas; Kolditz, Olaf

2015-04-01

In recent years, Germany's energy management has started to be transferred from fossil fuels to renewable and sustainable energy carriers. Renewable energy sources such as solar and wind power are subjected by fluctuations, thus the development and extension of energy storage capacities is a priority in German R&D programs. This work is a part of the ANGUS+ Project, funded by the federal ministry of education and research, which investigates the influence of subsurface energy storage on the underground. The utilization of subsurface salt caverns as a long-term storage reservoir for fossil fuels is a common method, since the construction of caverns in salt rock is inexpensive in comparison to solid rock formations due to solution mining. Another advantage of evaporate as host material is the self-healing behaviour of salt rock, thus the cavity can be assumed to be impermeable. In the framework of short-term energy storage (hours to days), caverns can be used as gas storage reservoirs for natural or artificial fuel gases, such as hydrogen, methane, or compressed air, where the operation pressures inside the caverns will fluctuate more frequently. This work investigates the influence of changing operation pressures at high frequencies on the stability of the host rock of gas storage caverns utilizing numerical models. Therefore, we developed a coupled Thermo-Hydro-Mechanical (THM) model based on the finite element method utilizing the open-source software platform OpenGeoSys. The salt behaviour is described by well-known constitutive material models which are capable of predicting creep, self-healing, and dilatancy processes. Our simulations include the thermodynamic behaviour of gas storage process, temperature development and distribution on the cavern boundary, the deformation of the cavern geometry, and the prediction of the dilatancy zone. Based on the numerical results, optimal operation modes can be found for individual caverns, so the risk of host rock damage can be minimized. Furthermore, the model can be used to design efficient monitoring programs to detect possible variations of the host rock due construction and operation of the storage facility. The developed model will be used by public authorities for land use planning issues.

Sulfur mass-independent fractionation in subsurface fracture waters indicates a long-standing sulfur cycle in Precambrian rocks.

PubMed

Li, L; Wing, B A; Bui, T H; McDermott, J M; Slater, G F; Wei, S; Lacrampe-Couloume, G; Lollar, B Sherwood

2016-10-27

The discovery of hydrogen-rich waters preserved below the Earth's surface in Precambrian rocks worldwide expands our understanding of the habitability of the terrestrial subsurface. Many deep microbial ecosystems in these waters survive by coupling hydrogen oxidation to sulfate reduction. Hydrogen originates from water-rock reactions including serpentinization and radiolytic decomposition of water induced by decay of radioactive elements in the host rocks. The origin of dissolved sulfate, however, remains unknown. Here we report, from anoxic saline fracture waters ∼2.4 km below surface in the Canadian Shield, a sulfur mass-independent fractionation signal in dissolved sulfate. We demonstrate that this sulfate most likely originates from oxidation of sulfide minerals in the Archaean host rocks through the action of dissolved oxidants (for example, HO · and H 2 O 2 ) themselves derived from radiolysis of water, thereby providing a coherent long-term mechanism capable of supplying both an essential electron donor (H 2 ) and a complementary acceptor (sulfate) for the deep biosphere.

Sulfur mass-independent fractionation in subsurface fracture waters indicates a long-standing sulfur cycle in Precambrian rocks

PubMed Central

Li, L.; Wing, B. A.; Bui, T. H.; McDermott, J. M.; Slater, G. F.; Wei, S.; Lacrampe-Couloume, G.; Lollar, B. Sherwood

2016-01-01

The discovery of hydrogen-rich waters preserved below the Earth's surface in Precambrian rocks worldwide expands our understanding of the habitability of the terrestrial subsurface. Many deep microbial ecosystems in these waters survive by coupling hydrogen oxidation to sulfate reduction. Hydrogen originates from water–rock reactions including serpentinization and radiolytic decomposition of water induced by decay of radioactive elements in the host rocks. The origin of dissolved sulfate, however, remains unknown. Here we report, from anoxic saline fracture waters ∼2.4 km below surface in the Canadian Shield, a sulfur mass-independent fractionation signal in dissolved sulfate. We demonstrate that this sulfate most likely originates from oxidation of sulfide minerals in the Archaean host rocks through the action of dissolved oxidants (for example, HO· and H2O2) themselves derived from radiolysis of water, thereby providing a coherent long-term mechanism capable of supplying both an essential electron donor (H2) and a complementary acceptor (sulfate) for the deep biosphere. PMID:27807346

An Overview on Measurement-While-Drilling Technique and its Scope in Excavation Industry

NASA Astrophysics Data System (ADS)

Rai, P.; Schunesson, H.; Lindqvist, P.-A.; Kumar, U.

2015-04-01

Measurement-while-drilling (MWD) aims at collecting accurate, speedy and high resolution information from the production blast hole drills with a target of characterization of highly variable rock masses encountered in sub-surface excavations. The essence of the technique rests on combining the physical drill variables in a manner to yield a fairly accurate description of the sub-surface rock mass much ahead of following downstream operations. In this light, the current paper presents an overview of the MWD by explaining the technique and its set-up, the existing drill-rock mass relationships and numerous on-going researches highlighting the real-time applications. Although the paper acknowledges the importance of concepts of specific energy, rock quality index and a couple of other indices and techniques for rock mass characterization, it must be distinctly borne in mind that the technique of MWD is highly site-specific, which entails derivation of site-specific calibration with utmost care.

Geologic hazards in the region of the Hurricane fault

USGS Publications Warehouse

Lund, W.R.

1997-01-01

Complex geology and variable topography along the 250-kilometer-long Hurricane fault in northwestern Arizona and southwestern Utah combine to create natural conditions that can present a potential danger to life and property. Geologic hazards are of particular concern in southwestern Utah, where the St. George Basin and Interstate-15 corridor north to Cedar City are one of Utah's fastest growing areas. Lying directly west of the Hurricane fault and within the Basin and Range - Colorado Plateau transition zone, this region exhibits geologic characteristics of both physiographic provinces. Long, potentially active, normal-slip faults displace a generally continuous stratigraphic section of mostly east-dipping late Paleozoic to Cretaceous sedimentary rocks unconformably overlain by Tertiary to Holocene sedimentary and igneous rocks and unconsolidated basin-fill deposits. Geologic hazards (exclusive of earthquake hazards) of principal concern in the region include problem soil and rock, landslides, shallow ground water, and flooding. Geologic materials susceptible to volumetric change, collapse, and subsidence in southwestern Utah include; expansive soil and rock, collapse-prone soil, gypsum and gypsiferous soil, soluble carbonate rocks, and soil and rock subject to piping and other ground collapse. Expansive soil and rock are widespread throughout the region. The Petrified Forest Member of the Chinle Formation is especially prone to large volume changes with variations in moisture content. Collapse-prone soils are common in areas of Cedar City underlain by alluvial-fan material derived from the Moenkopi and Chinle Formations in the nearby Hurricane Cliffs. Gypsiferous soil and rock are subject to dissolution which can damage foundations and create sinkholes. The principal formations in the region affected by dissolution of carbonate are the Kaibab and Toroweap Formations; both formations have developed sinkholes where crossed by perennial streams. Soil piping is common in southwestern Utah where it has damaged roads, canal embankments, and water-retention structures. Several unexplained sinkholes near the town of Hurricane possibly are the result of collapse of subsurface volcanic features. Geologic formations associated with slope failures along or near the Hurricane fault include rocks of both Mesozoic and Tertiary age. Numerous landslides are present in these materials along the Hurricane Cliffs, and the Petrified Forest Member of the Chinle Formation is commonly associated with slope failures where it crops out in the St. George Basin. Steep slopes and numerous areas of exposed bedrock make rock fall a hazard in the St. George Basin. Debris flows and debris floods in narrow canyons and on alluvial fans often accompany intense summer cloudburst thunderstorms. Flooded basements and foundation problems associated with shallow ground water are common on benches north of the Santa Clara River in the city of Santa Clara. Stream flooding is the most frequently occurring and destructive geologic hazard in southwestern Utah. Since the 1850s, there have been three major riverine (regional) floods and more than 300 damaging flash floods. Although a variety of flood control measures have been implemented, continued rapid growth in the region is again increasing vulnerability to flood hazards. Site-specific studies to evaluate geologic hazards and identify hazard-reduction measures are recommended prior to construction to reduce the need for costly repair, maintenance, or replacement of improperly placed or protected facilities.

The influence of subsurface porosity and bedrock composition on ecosystem productivity and drought resilience in the Sierra Nevada Batholith, California

NASA Astrophysics Data System (ADS)

Riebe, C. S.; Callahan, R. P.; Goulden, M.; Pasquet, S.; Flinchum, B. A.; Taylor, N. J.; Holbrook, W. S.

2017-12-01

The availability of water and nutrients in soil and weathered rock influences the distribution of Earth's terrestrial life and regulates ecosystem vulnerability to land use and climate change. We explored these relationships by combining geochemical and geophysical measurements at three mid-elevation sites in the Sierra Nevada, California. Forest cover correlates strongly with bedrock composition across the sites, implying strong lithologic control on the ecosystem. We evaluated two hypotheses about bedrock-ecosystem connections: 1) that bedrock composition influences vegetation by moderating plant-essential nutrient supply; and 2) that bedrock composition influences the degree of subsurface weathering, which influences vegetation by controlling subsurface water-storage capacity. To quantify subsurface water-holding capacity, we used seismic refraction surveys to infer gradients in P and S-wave velocity structure, which reveal variations in porosity when coupled together in a Hertz-Mindlin rock-physics model. We combined the geophysical data on porosity with bedrock bulk geochemistry measured in previous work to evaluate the influence of water-holding capacity and nutrient supply on ecosystem productivity, which we quantified using remote sensing. Our results show that more than 80% of the variance in ecosystem productivity can be explained by differences in bedrock phosphorus concentration and subsurface porosity, with phosphorus content being the dominant explanatory variable. This suggests that bedrock composition exerts a strong bottom-up control on ecosystem productivity through its influence on nutrient supply and weathering susceptibility, which in turn influences porosity. We show that vegetation vulnerability to drought stress and mortality can be explained in part by variations in subsurface water-holding capacity and rock-derived nutrient supply.

Lead isotopes and trace metals in dust at Yucca Mountain

USGS Publications Warehouse

Kwak, Loretta; Neymark, Leonid A.; Peterman, Zell E.

2008-01-01

Lead (Pb)-isotope compositions and trace-metal concentrations were determined for samples of dust collected from underground and surface locations at and near the proposed radioactive waste repository at Yucca Mountain, Nevada. Rare earth element concentrations in the dust samples from the underground tunnels are similar to those in wholerock samples of the repository host rocks (Miocene Tiva Canyon Tuff and Topopah Spring Tuff), supporting interpretation that the subsurface dust is mainly composed of rock comminuted during tunnel construction. Other trace metals (arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, lead, antimony, thallium, and zinc) are variably enriched in the subsurface dust samples relative to the average concentrations in the host rocks. Average concentrations of arsenic and lead in dust samples, high concentrations of which can cause corrosion of waste canisters, have enrichment factors from 1.2 to 1.6 and are insignificant relative to the range of concentrations for these metals observed in the host rock samples. Most dust samples from surface sites also are enriched in many of these trace metals relative to average repository host rocks. At least some of these enrichments may be artifacts of sampling. Plotted on a 208Pb/206Pb-207Pb/206Pb graph, Pb-isotope compositions of dust samples from underground sites form a mixing line extending from host-rock Pb-isotope compositions towards compositions of many of the dust samples from surface sites; however, combined Pb concentration and isotope data indicate the presence of a Pbenriched component in the subsurface dust that is not derived from host rock or surface dust and may derive from anthropogenic materials introduced into the underground environment.

The Shublik Formation and adjacent strata in northeastern Alaska description, minor elements, depositional environments and diagenesis

USGS Publications Warehouse

Tourtelot, Harry Allison; Tailleur, Irvin L.

1971-01-01

The Shublik Formation (Middle and Late Triassic) is widespread in the surface and subsurface of northern Alaska. Four stratigraphic sections along about 70 miles of the front of the northeastern Brooks Range east of the Canning giver were examined and sampled in detail in 1968. These sections and six-step spectrographic and carbon analyses of the samples combined with other data to provide a preliminary local description of the highly organic unit and of the paleoenvironments. Thicknesses measured between the overlying Kingak Shale of Jurassic age and the underlying Sadlerochit Formation of Permian and Triassic age range from 400 to more than 800 feet but the 400 feet, obtained from the most completely exposed section, may be closer to the real thickness across the region. The sections consist of organic-rich, phosphatic, and fossiliferous muddy, silty, or carbonate rocks. The general sequence consists, from the bottom up, of a lower unit of phosphatic siltstone, a middle unit of phosphatic carbonate rocks, and an upper unit of shale and carbonate rocks near the Canning River and shale, carbonate rocks, and sandstone to the east. Although previously designated a basal member of the Kingak Shale (Jurassic), the upper unit is here included with the Shublik on the basis of its regional lithologic relation. The minor element compositions of the samples of the Shublik Formation are consistent with their carbonaceous and phosphatic natures in that relatively large amounts of copper, molybdenum, nickel, vanadium and rare earths are present. The predominantly sandy rocks of the underlying Sadlerochit Formation (Permian and Triassic) have low contents of most minor elements. The compositions of samples of Kingak Shale have a wide range not readily explicable by the nature of the rock: an efflorescent sulfate salt contains 1,500 ppm nickel and 1,500 ppm zinc and large amounts of other metals derived from weathering of pyrite and leaching of local shale. The only recorded occurrence of silver and 300 ppm lead in gouge along a shear plane may be the result of metals introduced from an extraneous source. The deposits reflect a marine environment that deepened somewhat following deposition of the Sadlerochit Formation and then shoaled during deposition of the upper limestone-siltstone unit. This apparently resulted from a moderate transgression and regression of the sea with respect to a northwest-trending line between Barrow and the Brooks Range at the International Boundary. Nearer shore facies appear eastward. The phosphate in nodules, fossil molds and oolites, appears to have formed diagenetically within the uncompacted sediment.

Thermo-hydro-mechanical coupling in long-term sedimentary rock response

NASA Astrophysics Data System (ADS)

Makhnenko, R. Y.; Podladchikov, Y.

2017-12-01

Storage of nuclear waste or CO2 affects the state of stress and pore pressure in the subsurface and may induce large thermal gradients in the rock formations. In general, the associated coupled thermo-hydro-mechanical effect on long-term rock deformation and fluid flow have to be studied. Principles behind mathematical models for poroviscoelastic response are reviewed, and poroviscous model parameter, the bulk viscosity, is included in the constitutive equations. Time-dependent response (creep) of fluid-filled sedimentary rocks is experimentally quantified at isotropic stress states. Three poroelastic parameters are measured by drained, undrained, and unjacketed geomechanical tests for quartz-rich Berea sandstone, calcite-rich Apulian limestone, and clay-rich Jurassic shale. The bulk viscosity is calculated from the measurements of pore pressure growth under undrained conditions, which requires time scales 104 s. The bulk viscosity is reported to be on the order of 1015 Pa•s for the sandstone, limestone, and shale. It is found to be decreasing with the increase of pore pressure despite corresponding decrease in the effective stress. Additionally, increase of temperature (from 24 ºC to 40 ºC) enhances creep, where the most pronounced effect is reported for the shale with bulk viscosity decrease by a factor of 3. Viscous compaction of fluid-filled porous media allows a generation of a special type of fluid flow instability that leads to formation of high-porosity, high-permeability domains that are able to self-propagate upwards due to interplay between buoyancy and viscous resistance of the deforming porous matrix. This instability is known as "porosity wave" and its formation is possible under conditions applicable to deep CO2 storage in reservoirs and explains creation of high-porosity channels and chimneys. The reported experiments show that the formation of high-permeability pathways is most likely to occur in low-permeable clay-rich materials (caprock representatives) at elevated temperatures.

Terrestrial Subsurface Ecosystem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkins, Michael J.; Fredrickson, Jim K.

2015-10-15

The Earth’s crust is a solid cool layer that overlays the mantle, with a varying thickness of between 30-50 km on continental plates, and 5-10 km on oceanic plates. Continental crust is composed of a variety of igneous, metamorphic, and sedimentary rocks that weather and re-form over geologic cycles lasting millions to billions of years. At the crust surface, these weathered minerals and organic material combine to produce a variety of soils types that provide suitable habitats and niches for abundant microbial diversity (see Chapter 4). Beneath this soil zone is the subsurface. Once thought to be relatively free ofmore » microorganisms, recent estimates have calculated that between 1016-1017 g C biomass (2-19% of Earth’s total biomass) may be present in this environment (Whitman et al., 1998;McMahon and Parnell, 2014). Microbial life in the subsurface exists across a wide range of habitats: in pores associated with relatively shallow unconsolidated aquifer sediments to fractures in bedrock formations that are more than a kilometer deep, where extreme lithostatic pressures and temperatures are encountered. While these different environments contain varying physical and chemical conditions, the absence of light is a constant. Despite this, diverse physiologies and metabolisms enable microorganisms to harness energy and carbon for growth in water-filled pore spaces and fractures. Carbon and other element cycles are driven by microbial activity, which has implications for both natural processes and human activities in the subsurface, e.g., bacteria play key roles in both hydrocarbon formation and degradation. Hydrocarbons are a major focus for human utilization of the subsurface, via oil and gas extraction and potential geologic CO2 sequestration. The subsurface is also utilized or being considered for sequestered storage of high-level radioactive waste from nuclear power generation and residual waste from past production of weapons grade nuclear materials. While our understanding of the subsurface is continually improving, it is clear that only a small fraction of microbial habitats have been sampled and studied. In this chapter, we will discuss these studies in the context of the distribution of microbial life in the subsurface, the stresses that microorganisms must overcome to survive in these environments, and the metabolic strategies that are employed to harness energy in a region of the planet far-removed from sunlight. Finally, we will consider both beneficial and deleterious effects of microbial activity in the subsurface on human activities in this environment.« less

Geochemistry of surface and subsurface waters in quartz-sandstones: significance for the geomorphic evolution of tepui table mountains (Gran Sabana, Venezuela)

NASA Astrophysics Data System (ADS)

Mecchia, Marco; Sauro, Francesco; Piccini, Leonardo; De Waele, Jo; Sanna, Laura; Tisato, Nicola; Lira, Jesus; Vergara, Freddy

2014-04-01

In situ measurements of discharge, pH, electric conductivity (EC), temperature, and SiO2 content have been carried out during five expeditions in the last 20 years on the summit plateaus, inside caves and along the rivers of the surrounding lowlands of three tepui massifs in Venezuela (Auyan, Roraima, and Chimanta). Additionally, detailed chemical analyses were performed on waters sampled in a newly discovered extensive quartz-sandstone cave system on the Auyan Tepui. Rock samples of the quartz-sandstone bedrock from different locations have been analysed to obtain their chemical composition with a wavelength dispersive X-ray fluorescence spectrometer. These data show that the majority of silica present in surface and subsurface water comes from dissolution of quartz and only in minor amount from hydrolysis of other silicate minerals. Probably the presence of a hardened crust of iron hydroxides limits the dissolution of silica on the top surface of tepuis. Dissolution in the subsurface, instead, is more significant and causes, in the long term, the “arenisation” of the quartz-sandstone and its subsequent removal by mechanical erosion. On the other hand, waters flowing on the arkosic rock outcropping on the lowland below the tepuis obtain their high dissolved silica content mainly from hydrolysis of silicates. The morphological evolution of these table mountains appears thus to be controlled mainly by the underground weathering of the quartz-sandstone, with the opening of deep fractures (grietas) and the collapse of large underground horizontal cave systems. Scarp retreat, instead, seems to be related to the higher weathering rate of the more arkosic formations underlying the quartz-sandstones.

The influence of Critical Zone structure on runoff paths, seasonal water storage, and ecosystem composition

NASA Astrophysics Data System (ADS)

Hahm, W. J.; Dietrich, W. E.; Rempe, D.; Dralle, D.; Dawson, T. E.; Lovill, S.; Bryk, A.

2017-12-01

Understanding how subsurface water storage mediates water availability to ecosystems is crucial for elucidating linkages between water, energy, and carbon cycles from local to global scales. Earth's Critical Zone (the CZ, which extends from the top of the vegetation canopy downward to fresh bedrock) includes fractured and weathered rock layers that store and release water, thereby contributing to ecosystem water supplies, and yet are not typically represented in land-atmosphere models. To investigate CZ structural controls on water storage dynamics, we intensively studied field sites in a Mediterranean climate where winter rains arrive months before peak solar energy availability, resulting in strong summertime ecosystem reliance on stored subsurface water. Intra-hillslope and catchment-wide observations of CZ water storage capacity across a lithologic boundary in the Franciscan Formation of the Northern California Coast Ranges reveal large differences in the thickness of the CZ and water storage capacity that result in a stark contrast in plant community composition and stream behavior. Where the CZ is thick, rock moisture storage supports forest transpiration and slow groundwater release sustains baseflow and salmon populations. Where the CZ is thin, limited water storage is used by an oak savanna ecosystem, and streams run dry in summer due to negligible hillslope drainage. At both sites, wet season precipitation replenishes the dynamic storage deficit generated during the summer dry season, with excess winter rains exiting the watersheds via storm runoff as perched groundwater fracture flow at the thick-CZ site and saturation overland flow at the thin-CZ site. Annual replenishment of subsurface water storage even in severe drought years may lead to ecosystem resilience to climatic perturbations: during the 2011-2015 drought there was not widespread forest die-off in the study area.

Fundamental study of CO2-H2O-mineral interactions for carbon sequestration, with emphasis on the nature of the supercritical fluid-mineral interface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bryan, Charles R.; Dewers, Thomas A.; Heath, Jason E.

2013-09-01

In the supercritical CO2-water-mineral systems relevant to subsurface CO2 sequestration, interfacial processes at the supercritical fluid-mineral interface will strongly affect core- and reservoir-scale hydrologic properties. Experimental and theoretical studies have shown that water films will form on mineral surfaces in supercritical CO2, but will be thinner than those that form in vadose zone environments at any given matric potential. The theoretical model presented here allows assessment of water saturation as a function of matric potential, a critical step for evaluating relative permeabilities the CO2 sequestration environment. The experimental water adsorption studies, using Quartz Crystal Microbalance and Fourier Transform Infrared Spectroscopymore » methods, confirm the major conclusions of the adsorption/condensation model. Additional data provided by the FTIR study is that CO2 intercalation into clays, if it occurs, does not involve carbonate or bicarbonate formation, or significant restriction of CO2 mobility. We have shown that the water film that forms in supercritical CO2 is reactive with common rock-forming minerals, including albite, orthoclase, labradorite, and muscovite. The experimental data indicate that reactivity is a function of water film thickness; at an activity of water of 0.9, the greatest extent of reaction in scCO2 occurred in areas (step edges, surface pits) where capillary condensation thickened the water films. This suggests that dissolution/precipitation reactions may occur preferentially in small pores and pore throats, where it may have a disproportionately large effect on rock hydrologic properties. Finally, a theoretical model is presented here that describes the formation and movement of CO2 ganglia in porous media, allowing assessment of the effect of pore size and structural heterogeneity on capillary trapping efficiency. The model results also suggest possible engineering approaches for optimizing trapping capacity and for monitoring ganglion formation in the subsurface.« less

Predicting the Stochastic Properties of the Shallow Subsurface for Improved Geophysical Modeling

NASA Astrophysics Data System (ADS)

Stroujkova, A.; Vynne, J.; Bonner, J.; Lewkowicz, J.

2005-12-01

Strong ground motion data from numerous explosive field experiments and from moderate to large earthquakes show significant variations in amplitude and waveform shape with respect to both azimuth and range. Attempts to model these variations using deterministic models have often been unsuccessful. It has been hypothesized that a stochastic description of the geological medium is a more realistic approach. To estimate the stochastic properties of the shallow subsurface, we use Measurement While Drilling (MWD) data, which are routinely collected by mines in order to facilitate design of blast patterns. The parameters, such as rotation speed of the drill, torque, and penetration rate, are used to compute the rock's Specific Energy (SE), which is then related to a blastability index. We use values of SE measured at two different mines and calibrated to laboratory measurements of rock properties to determine correlation lengths of the subsurface rocks in 2D, needed to obtain 2D and 3D stochastic models. The stochastic models are then combined with the deterministic models and used to compute synthetic seismic waveforms.

Using geothermal energy to heat a portion of a formation for an in situ heat treatment process

DOEpatents

Pieterson, Roelof; Boyles, Joseph Michael; Diebold, Peter Ulrich

2010-06-08

Methods of using geothermal energy to treat subsurface formations are described herein. Methods for using geothermal energy to treat a subsurface treatment area containing or proximate to hydrocarbons may include producing geothermally heated fluid from at least one subsurface region. Heat from at least a portion of the geothermally heated fluid may be transferred to the subsurface treatment area to heat the subsurface treatment area. At least some hydrocarbon fluids may be produced from the formation.

Subsurface drainage erodes forested granitic terrane

Treesearch

Philip Durgin

1984-01-01

Abstract - Solution and landsliding, the dominant erosion processes in undisturbed forested mountainous watersheds, are both influenced by subsurface drainage. Biological processes that generate organic acids accelerate loss of dissolved solids by promoting the dissolution of primary minerals in granitic rock. These organic acids can also disperse the secondary...

Paleontologic and stratigraphic relations of phosphate beds in Upper Cretaceous rocks of the Cordillera Oriental, Colombia

USGS Publications Warehouse

Maughan, Edwin K.; Zambrano O., Francisco; Mojica G., Pedro; Abozaglo M., Jacob; Pachon P., Fernando; Duran R., Raul

1979-01-01

Phosphorite crops out in the Cordillera Oriental of the Colombian Andes in rocks of Late Cretaceous age as strata composed mostly of pelletal carbonate fluorapatite. One stratum of Santonian age near the base of the Galembo Member of the La Luna Formation crops out at many places in the Departments of Santander and Norte de Santander and may be of commercial grade. This stratum is more than one meter thick at several places near Lebrija and near Sardinata, farther south it is locally one meter thick or more near the base of the Guadalupe Formation in the Department of Boyaca. Other phosphorite beds are found at higher stratigraphic levels in the Galembo Member and the Guadalupe Formation, and at some places these may be commercial also. A stratigraphically lower phosphorite occurs below the Galembo Member in the Capacho Formation (Cenomanian age) in at least one area near the town of San Andres, Santander. A phosphorite or pebbly phosphate conglomerate derived from erosion of the Galembo Member forms the base of the Umir Shale and the equivalent Colon Shale at many places. Deposition of the apatite took place upon the continental shelf in marine water of presumed moderate depth between the Andean geosyncline and near-shore detrital deposits adjacent to the Guayana shield. Preliminary calculations indicate phosphorite reserves of approximately 315 million metric tons in 9 areas, determined from measurements of thickness, length of the outcrop, and by projecting the reserves to a maximum of 1,000 meters down the dip of the strata into the subsurface. Two mines were producing phosphate rock in 1969; one near Turmeque, Boyaca, and the other near Tesalia, Huila.

Facies-related fracturing in turbidites: insights from the Marnoso-Arenacea Fm. (Northern Apennines, Italy)

NASA Astrophysics Data System (ADS)

Ogata, Kei; Storti, Fabrizio; Balsamo, Fabrizio; Bedogni, Enrico; Tinterri, Roberto; Fetter, Marcos; Gomes, Leonardo; Hatushika, Raphael

2016-04-01

Natural fractures deeply influence subsurface fluid flow, exerting a primary control on resources like aquifers, hydrocarbons and geothermal reservoirs, and on environmental issues like CO2 storage and nuclear waste disposal. In layered sedimentary rocks, depositional processes-imprinted rock rheology favours the development of both mechanical anisotropy and heterogeneity on a wide range of scales, and are thus expected to strongly influence location and frequency of fractures. To better constrain the contribution of stratigraphic, sedimentological and petrophysical attributes, we performed a high-resolution, multidisciplinary study on a selected stratigraphic interval of jointed foredeep turbidites in the Miocene Marnoso-arenacea Formation (Northern Apennines, Italy), which are characterised by a great lateral and vertical variability of grain-size and depositional structures. Statistical relationships among field and laboratory data significantly improve when the single facies scale is considered, and, for similar facies recording different evolutionary stages of the parent turbidity currents, we observed a direct correlation between the three-dimensional anisotropies of rock hardness tensors and the normalized fracture frequencies, testifying for the primary sedimentary flow-related control on fracture distributions.

Micro Mechanics and Microstructures of Major Subsurface Hydraulic Barriers: Shale Caprock vs Wellbore Cement

NASA Astrophysics Data System (ADS)

Radonjic, M.; Du, H.

2015-12-01

Shale caprocks and wellbore cements are two of the most common subsurface impermeable barriers in the oil and gas industry. More than 60% of effective seals for geologic hydrocarbon bearing formations as natural hydraulic barriers constitute of shale rocks. Wellbore cements provide zonal isolation as an engineered hydraulic barrier to ensure controlled fluid flow from the reservoir to the production facilities. Shale caprocks were deposited and formed by squeezing excess formation water and mineralogical transformations at different temperatures and pressures. In a similar process, wellbore cements are subjected to compression during expandable tubular operations, which lead to a rapid pore water propagation and secondary mineral precipitation within the cement. The focus of this research was to investigate the effect of wellbore cement compression on its microstructure and mechanical properties, as well as a preliminary comparison of shale caprocks and hydrated cement. The purpose of comparative evaluation of engineered vs natural hydraulic barrier materials is to further improve wellbore cement durability when in contact with geofluids. The micro-indentation was utilized to evaluate the change in cement mechanical properties caused by compression. Indentation experiments showed an overall increase in hardness and Young's modulus of compressed cement. Furthermore, SEM imaging and Electron Probe Microanalysis showed mineralogical alterations and decrease in porosity. These can be correlated with the cement rehydration caused by microstructure changes as a result of compression. The mechanical properties were also quantitatively compared to shale caprock samples in order to investigate the similarities of hydraulic barrier features that could help to improve the subsurface application of cement in zonal isolation. The comparison results showed that the poro-mechanical characteristics of wellbore cement appear to be improved when inherent pore sizes are shifted to predominantly nano-scale range as characteristic of pore-size distribution typical for shale rocks. The effect of compression on cement appears to petrophysically alter cement towards the properties of shale caprocks, although the process is achieved much faster than in the case of shale diagenesis over geological times.

Gold in the Black Hills, South Dakota, and how new deposits might be found

USGS Publications Warehouse

Norton, James Jennings

1974-01-01

Of the recorded production of 34,694,552 troy ounces of gold mined in South Dakota through 1971, about 90 percent has come from Precambrian ore bodies in the Homestake mine at Lead in the northern Black Hills. Most of the rest has come from ore deposited in the Deadwood Formation (Cambrian) by hydrothermal replacement during early Tertiary igneous activity. About 99 percent of the total production has been within a radius of 5 miles (8 km) of Lead. Elsewhere, prospecting has been intense, both in the Precambrian rocks, which are exposed over an area 61 by 26 miles (98 by 42 km), and in nearby Paleozoic rocks. All the known ore bodies have been found either at the surface or in subsurface workings of operating mines. Efforts to find totally new deposits have been modest and sporadic; no comprehensive and systematic program has ever been attempted. Obviously, any exploration program should be aimed at finding a new deposit resembling the Homestake in the Precambrian, but discovery in the Deadwood of a new group of ore bodies containing several hundred thousand ounces of gold would certainly be worthwhile. Evidence has long been available that the Deadwood deposits and the Homestake deposit are somehow related. Current opinion is that (1) the Homestake ore is mainly Precambrian, (2) a trivial amount of Homestake ore is Tertiary, (3)gold in Deadwood basal conglomerate is largely of placer origin, and (4) the gold of replacement deposits in the Deadwood and in other rock units came originally from sources similar to the Homestake deposit or its parent materials. Homestake ore is virtually entirely contained in a unit of iron-formation locally known as the Homestake Formation, which seemingly had more gold in the original sediments than similar rocks exposed elsewhere in the Black Hills. Gold, sulfur, and other constituents were subsequently concentrated in ore shoots in zones of dilation caused by cross folds that deformed earlier major folds. These ore shoots are in metamorphic rocks of a grade just above the garnet isograd, in a zone where the principal iron-magnesium mineral of the iron-formation changes from a carbonate (sideroplesite) to a silicate (cummingtonite). This metamorphic reaction would release carbon dioxide to the fluid that presumably formed the ore bodies. In short, three controls over localization of the ore have been identified: (1) the cross folds; (2) the so-called Homestake Formation, which passes beneath Paleozoic rocks north of Lead and has not been proved to reappear anywhere else in the Black Hills (Other units of iron-formation less enriched in gold might locally become more like the Homestake Formation beneath the cover of Paleozoic rocks.}; (3} proximity to the garnet isograd--nearly all the exposed Precambrian rocks in the Black Hills are at a metamorphic grade higher than this isograd--and occurrence of this isograd zone mostly beneath Paleozoic rocks. In searching for new deposits, one can guess from existing data where Precambrian rocks of suitable nature may be concealed. The usefulness of such guesses can be increased if they are made with information about the distribution of gold in younger rocks. Gold in the Deadwood basal conglomerate would be the simplest indicator of a deposit once exposed on the pre-Deadwood surface. Tertiary replacement deposits in the Deadwood or other rocks, which obtained their gold from Precambrian sources that may be nearby or far away, can also be helpful; they, like anomalies found by geochemical sampling, at least outline the regions of mineralizing activity. A suitable approach to exploration is to make a thorough study of the stratigraphy, the structure, and the metals geochemistry of the Deadwood Formation and associated rocks, chiefly in the northern Black Hills but to a lesser extent elsewhere in localities where the Precambrian geology seems promising and where gold has been found nearby. Such a program, even if it does not yield

Nature of the Martian uplands: Effect on Martian meteorite age distribution and secondary cratering

NASA Astrophysics Data System (ADS)

Hartmann, William K.; Barlow, Nadine G.

2006-10-01

Martian meteorites (MMs) have been launched from an estimated 5-9 sites on Mars within the last 20 Myr. Some 80-89% of these launch sites sampled igneous rock formations from only the last 29% of Martian time. We hypothesize that this imbalance arises not merely from poor statistics, but because the launch processes are dominated by two main phenomena: first, much of the older Martian surface is inefficient in launching rocks during impacts, and second, the volumetrically enormous reservoir of original cumulate crust enhances launch probability for 4.5 Gyr old rocks. There are four lines of evidence for the first point, not all of equal strength. First, impact theory implies that MM launch is favored by surface exposures of near-surface coherent rock (≤102 m deep), whereas Noachian surfaces generally should have ≥102 m of loose or weakly cemented regolith with high ice content, reducing efficiency of rock launch. Second, similarly, both Mars Exploration Rovers found sedimentary strata, 1-2 orders of magnitude weaker than Martian igneous rocks, favoring low launch efficiency among some fluvial-derived Hesperian and Noachian rocks. Even if launched, such rocks may be unrecognized as meteorites on Earth. Third, statistics of MM formation age versus cosmic-ray exposure (CRE) age weakly suggest that older surfaces may need larger, deeper craters to launch rocks. Fourth, in direct confirmation, one of us (N. G. B.) has found that older surfaces need larger craters to produce secondary impact crater fields (cf. Barlow and Block 2004). In a survey of 200 craters, the smallest Noachian, Hesperian, and Amazonian craters with prominent fields of secondaries have diameters of ˜45 km, ˜19 km, and ˜10 km, respectively. Because 40% of Mars is Noachian, and 74% is either Noachian or Hesperian, the subsurface geologic characteristics of the older areas probably affect statistics of recognized MMs and production rates of secondary crater populations, and the MM and secondary crater statistics may give us clues to those properties.

INLAND DISSOLVED SALT CHEMISTRY: STATISTICAL EVALUATION OF BIVARIATE AND TERNARY DIAGRAM MODELS FOR SURFACE AND SUBSURFACE WATERS

EPA Science Inventory

We compared the use of ternary and bivariate diagrams to distinguish the effects of atmospheric precipitation, rock weathering, and evaporation on inland surface and subsurface water chemistry. The three processes could not be statistically differentiated using bivariate models e...

Regional Big Injun (Price/Pocono) subsurface stratigraphy of West Virginia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donaldson, A.C.; Zou, Xiangdong

1992-01-01

The lower Big Injun (Lower Mississippian) is the oil reservoir of the Granny Creek and Rock Creek fields and consists of multiple sandstones that were deposited in different fluvial-deltaic depositional environments. These multiple sandstones became amalgamated and now appear as a widespread blanket sandstone as a result of ancient cut and fill processes associated with river-channel sedimentation. The regional study of this Price Formation subsurface equivalent considers the continuity and thickness variations of the composite sandstones of the Big Injun mainly within western West Virginia. The major fluvial drainage system apparently flowed southward through Ohio (much of it later erodedmore » by the pre-Pottsville unconformity) during Big Injun time (and earlier) and part of the system was diverted into southwestern West Virginia as vertically stacked channel and river-mouth bar deposits (Rock Creek field). This ancient Ontario River system apparently drained a huge area including the northern craton as well as the orogenic belt. The emerging West Virginia Dome probably sourced the sediment transported by small rivers developing southwestward prograding deltas across Clay County (Granny Creek field). Sedimentation was affected by differential subsidence in the basin. Paleovalley fill was considered for areas with vertically stacked sandstones, but evidence for their origin is not convincing. Oil-reservoir sandstones are classified as dip-trending river channel (D1) and deltaic shoreline (D2) deposits.« less

Surface and subsurface facies architecture of a small hydroexplosive, rhyolitic centre in the Mesoproterozoic Gawler Range Volcanics, South Australia

NASA Astrophysics Data System (ADS)

Roache, M. W.; Allen, S. R.; McPhie, J.

2000-12-01

At Menninnie Dam, South Australia, a drilling program has revealed a complete section through the subsurface feeder system and erupted products of a small, hydroexplosive, rhyolitic centre within the Mesoproterozoic Gawler Range Volcanics. Porphyritic rhyolite intruded near-vertical faults in the Palaeoproterozoic basement and at less than a few hundred metres depth, interacted with fault-hosted (hot?) groundwater. Hydrofracturing of the wall rock occurred in advance of and at the margins of the rhyolitic intrusions. The rhyolitic intrusions have peperitic margins and grade into discordant lithic-rich PB facies. The advancing fragmentation front intersected the palaeosurface, triggering phreatic eruptions that deposited a poorly sorted, lithic-rich explosion breccia. Rhyolite then rose to the surface through the intrusive breccias and shallow-seated magma-water interaction occurred in the conduit within <50 m of the surface. As the magma discharge rate increased, ;dry; explosive activity prevailed. A fall deposit, the top of which is welded, was deposited close to the vent, and in more distal locations (>800 m from the inferred source), the products include muddy sandstone and pumice breccia. At the end of the eruption, rhyolitic lava was extruded in the form of a small dome. The presence of contemporaneous Pb-Zn-Ag mineralisation in the wall rocks suggests that an active hydrothermal system may have been involved in the formation of the Menninnie Dam hydroexplosive volcanic centre.

30 CFR 250.801 - Subsurface safety devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... conditions, hydrate formation, or paraffins, an alternate setting depth of the subsurface safety device may... conditions such as permafrost, unstable bottom conditions, hydrate formations, and paraffins. (g) Subsurface...

Characterizing a Mississippian Carbonate Reservoir for CO2-EOR and Carbon Geosequestration: Applicability of Existing Rock Physics Models and Implications to Feasibility of a Time Lapse Monitoring Program in the Wellington Oil Field, Sumner County, Kansas.

NASA Astrophysics Data System (ADS)

Lueck, A. J.; Raef, A. E.

2015-12-01

This study will focus on characterizing subsurface rock formations of the Wellington Field, in Sumner County, Kansas, for both geosequestration of carbon dioxide (CO2) in the saline Arbuckle formation and enhanced oil recovery of a depleting Mississippian oil reservoir. Multi-scale data including lithofacies core samples, X-ray diffraction, digital rock physics scans, scanning electron microscope (SEM) imaging, well log data including sonic and dipole sonic, and surface 3D seismic reflection data will be integrated to establish and/or validate a new or existing rock physics model that best represents our reservoir rock types and characteristics. We will acquire compressional wave velocity and shear wave velocity data from Mississippian and Arbuckle cores by running ultrasonic tests using an Ult 100 Ultrasonic System and a 12 ton hydraulic jack located in the geophysics lab in Thompson Hall at Kansas State University. The elastic constants Young's Modulus, Bulk Modulus, Shear (Rigidity) Modulus and Poisson's Ratio will be extracted from these velocity data. Ultrasonic velocities will also be compared to sonic and dipole sonic log data from the Wellington 1-32 well. These data will be integrated to validate a lithofacies classification statistical model, which will be and partially has been applied to the largely unknown saline Arbuckle formation, with hopes for a connection, perhaps via Poisson's ratio, allowing a time-lapse seismic feasibility assessment and potentially developing a transformation of compressional wave sonic velocities to shear wave sonic for all wells, where compressional wave sonic is available. We will also be testing our rock physics model by predicting effects of changing effective (brine + CO2 +hydrocarbon) fluid composition on seismic properties and the implications on feasibility of seismic monitoring. Lessons learned from characterizing the Mississippian are essential to understanding the potential of utilizing similar workflows for the much less known saline aquifer of the Arbuckle in south central Kansas.

Petrophysics and hydrocarbon potential of Paleozoic rocks in Kuwait

NASA Astrophysics Data System (ADS)

Abdullah, Fowzia; Shaaban, Fouad; Khalaf, Fikry; Bahaman, Fatma; Akbar, Bibi; Al-Khamiss, Awatif

2017-10-01

Well logs from nine deep exploratory and development wells in Kuwaiti oil fields have been used to study petrophysical characteristics and their effect on the reservoir quality of the subsurface Paleozoic Khuff and Unayzah formations. Petrophysical log data have been calibrated with core analysis available at some intervals. The study indicates a complex lithological facies of the Khuff Formation that is composed mainly of dolomite and anhydrite interbeds with dispersed argillaceous materials and few limestone intercalations. This facies greatly lowered the formation matrix porosity and permeability index. The porosity is fully saturated with water, which is reflected by the low resistivity logs responses, except at some intervals where few hydrocarbon shows are recorded. The impermeable anhydrites, massive (low-permeability) carbonate rock and shale at the lower part of the formation combine to form intraformational seals for the clastic reservoirs of the underlying Unayzah Formation. By contrast, the log interpretation revealed clastic lithological nature of the Unayzah Formation with cycles of conglomerate, sandstone, siltstone, mudstone and shales. The recorded argillaceous materials are mainly of disseminated habit, which control, for some extent, the matrix porosity, that ranges from 2% to 15% with water saturation ranges from 65% to 100%. Cementation, dissolution, compaction and clay mineral authigenesis are the most significant diagenetic processes affecting the reservoir quality. Calibration with the available core analysis at some intervals of the formation indicates that the siliciclastic sequence is a fluvial with more than one climatic cycle changes from humid, semi-arid to arid condition and displays the impact of both physical and chemical diagenesis. In general, the study revealed that the Unyazah Formation has a better reservoir quality than the Khuff Formation and possible gas bearing zones.

Two-way feedback between biology and deep Earth processes

NASA Astrophysics Data System (ADS)

Sleep, N. H.; Pope, E.; Bird, D.

2012-12-01

The presence of the metamorphic products of banded iron formation and black shale indicate that the Earth teemed with life by the time of the earliest preserved rocks, ca. 3.85 Ga. Iron and sulfur-based anoxygenic photosynthesis with full carbon cycles was present by this time. The pH of the ocean was ~8. The lack of older rock record cloaks pre-biotic evolution and the origin of life. Nascent and early life obtained energy from chemical disequilibria in rocks rather than sunlight. Appraising putative rock pre-biological environments is difficult in that life has modified the composition of the atmosphere, the hydrosphere, and sedimentary rocks. It has greatly affected the composition of crystalline crustal rocks and measurably modified the mantle. Conversely, hard crustal rocks and the mantle likely sequester a very ancient record of last resort. Theory provides additional insight. The Earth's surface and interior cooled following the moon-forming impact. The oceans passed through conditions favored by thermophile organisms before becoming clement. Ocean pH was ~6 and bars of CO2 existed in the atmosphere. Subduction removed the CO2 into the mantle before the time of rock record. Serpentinite likely existed in land, tidal, and marine environments as it does today. Seafloor spreading and arc volcanism likely drove hydrothermal circulation. The late heavy bombardment occurred after ca. 4.1 Ga; low heat flow environments and hence habitable subsurface refugia existed. It is conceivable that one or a few ocean-boiling impacts left thermophile survivors in their wake. Overall, the molecular biology of extant life likely conserves features that relate to its earliest abodes.

ELF-VLF communications through the Earth Project report for calendar year 1984, revision 1

NASA Astrophysics Data System (ADS)

Buettner, H. M.; Burker, G. J.; Didwall, E. M.; Holladay, G.; Lytle, R. J.

1985-08-01

We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-Earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constant of the rock, the noise characteristics, and the modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

ELF-VLF communications through-the-Earth

NASA Astrophysics Data System (ADS)

Buettner, H. M.; Burke, G. J.; Didwall, E. M.; Holladay, G.; Lytle, R. J.

1985-06-01

We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified Earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-Earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constants of the rock, the noise characteristics, and modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

Advanced core-analyses for subsurface characterization

NASA Astrophysics Data System (ADS)

Pini, R.

2017-12-01

The heterogeneity of geological formations varies over a wide range of length scales and represents a major challenge for predicting the movement of fluids in the subsurface. Although they are inherently limited in the accessible length-scale, laboratory measurements on reservoir core samples still represent the only way to make direct observations on key transport properties. Yet, properties derived on these samples are of limited use and should be regarded as sample-specific (or `pseudos'), if the presence of sub-core scale heterogeneities is not accounted for in data processing and interpretation. The advent of imaging technology has significantly reshaped the landscape of so-called Special Core Analysis (SCAL) by providing unprecedented insight on rock structure and processes down to the scale of a single pore throat (i.e. the scale at which all reservoir processes operate). Accordingly, improved laboratory workflows are needed that make use of such wealth of information by e.g., referring to the internal structure of the sample and in-situ observations, to obtain accurate parameterisation of both rock- and flow-properties that can be used to populate numerical models. We report here on the development of such workflow for the study of solute mixing and dispersion during single- and multi-phase flows in heterogeneous porous systems through a unique combination of two complementary imaging techniques, namely X-ray Computed Tomography (CT) and Positron Emission Tomography (PET). The experimental protocol is applied to both synthetic and natural porous media, and it integrates (i) macroscopic observations (tracer effluent curves), (ii) sub-core scale parameterisation of rock heterogeneities (e.g., porosity, permeability and capillary pressure), and direct 3D observation of (iii) fluid saturation distribution and (iv) the dynamic spreading of the solute plumes. Suitable mathematical models are applied to reproduce experimental observations, including both 1D and 3D numerical schemes populated with the parameterisation above. While it validates the core-flooding experiments themselves, the calibrated mathematical model represents a key element for extending them to conditions prevalent in the subsurface, which would be otherwise not attainable in the laboratory.

Microbial Life Driving Low-Temperature Basalt Alteration in the Subsurface: Decoupling Abiotic Processes from Biologically-Mediated Rock Alteration

NASA Astrophysics Data System (ADS)

Moore, R.; Lecoeuvre, A.; Stephant, S.; Dupraz, S.; Ranchou-Peyruse, M.; Ranchou-Peyruse, A.; Gérard, E.; Ménez, B.

2017-12-01

Microorganisms are involved with specific rock alteration processes in the deep subsurface. It is a challenge to link any contribution microbial life may have on rock alteration with specific functions or phyla because many alteration features and secondary minerals produced by metabolic processes can also produce abiotically. Here, two flow-through experiments were designed to mimic the circulation of a CO2-rich fluid through crystalline basalt. In order to identify microbially-mediated alteration and be able to link it with specific metabolisms represented in the subsurface, a relatively fresh crystalline basalt substrate was subsampled, sterilized and used as the substrate for both experiments. In one experiment, the substrate was left sterile, and in the other it was inoculated with an enrichment culture derived from the same aquifer as the rock substrate. Initial results show that the inoculum contained Proteobacteria and Firmicutes, which have diverse metabolic potentials. Fluid and rock analyses before, during, and after the experiments show that mineralogy, fluid chemistry, and dissolution processes differ between the sterile and inoculated systems. In the inoculated experiment iron-rich orthopyroxenes were preferentially dissolved while in the sterile system clinopyroxenes and plagioclases both exhibited a higher degree of dissolution. Additionally, the patterns of CO2 consumption and production over the duration of both experiments is different. This suggest that in a low-temperature basalt system with microorganisms CO2 is either consumed to produce biomass, or that carbonates are produced and then subsequently preserved. This suite of results combined with molecular ecology analyses can be used to conclude that in low-temperature basalts microorganisms play an intrinsic role in rock alteration.

Integrating non-colocated well and geophysical data to capture subsurface heterogeneity at an aquifer recharge and recovery site

NASA Astrophysics Data System (ADS)

Gottschalk, Ian P.; Hermans, Thomas; Knight, Rosemary; Caers, Jef; Cameron, David A.; Regnery, Julia; McCray, John E.

2017-12-01

Geophysical data have proven to be very useful for lithological characterization. However, quantitatively integrating the information gained from acquiring geophysical data generally requires colocated lithological and geophysical data for constructing a rock-physics relationship. In this contribution, the issue of integrating noncolocated geophysical and lithological data is addressed, and the results are applied to simulate groundwater flow in a heterogeneous aquifer in the Prairie Waters Project North Campus aquifer recharge site, Colorado. Two methods of constructing a rock-physics transform between electrical resistivity tomography (ERT) data and lithology measurements are assessed. In the first approach, a maximum likelihood estimation (MLE) is used to fit a bimodal lognormal distribution to horizontal crosssections of the ERT resistivity histogram. In the second approach, a spatial bootstrap is applied to approximate the rock-physics relationship. The rock-physics transforms provide soft data for multiple point statistics (MPS) simulations. Subsurface models are used to run groundwater flow and tracer test simulations. Each model's uncalibrated, predicted breakthrough time is evaluated based on its agreement with measured subsurface travel time values from infiltration basins to selected groundwater recovery wells. We find that incorporating geophysical information into uncalibrated flow models reduces the difference with observed values, as compared to flow models without geophysical information incorporated. The integration of geophysical data also narrows the variance of predicted tracer breakthrough times substantially. Accuracy is highest and variance is lowest in breakthrough predictions generated by the MLE-based rock-physics transform. Calibrating the ensemble of geophysically constrained models would help produce a suite of realistic flow models for predictive purposes at the site. We find that the success of breakthrough predictions is highly sensitive to the definition of the rock-physics transform; it is therefore important to model this transfer function accurately.

FIELD INVESTIGATIONS OF THE DRIFT SHADOW

DOE Office of Scientific and Technical Information (OSTI.GOV)

G. W. Su, T. J. Kneafsey, T. A. Ghezzehei, B. D. Marshall, and P. J. Cook

The ''Drift Shadow'' is defined as the relatively drier region that forms below subsurface cavities or drifts in unsaturated rock. Its existence has been predicted through analytical and numerical models of unsaturated flow. However, these theoretical predictions have not been demonstrated empirically to date. In this project they plan to test the drift shadow concept through field investigations and compare our observations to simulations. Based on modeling studies they have an identified suitable site to perform the study at an inactive mine in a sandstone formation. Pretest modeling studies and preliminary characterization of the site are being used to developmore » the field scale tests.« less

Molten salt as a heat transfer fluid for heating a subsurface formation

DOEpatents

Nguyen, Scott Vinh; Vinegar, Harold J.

2010-11-16

A heating system for a subsurface formation includes a conduit located in an opening in the subsurface formation. An insulated conductor is located in the conduit. A material is in the conduit between a portion of the insulated conductor and a portion of the conduit. The material may be a salt. The material is a fluid at operating temperature of the heating system. Heat transfers from the insulated conductor to the fluid, from the fluid to the conduit, and from the conduit to the subsurface formation.

Feasibility study of a rock plant filter wastewater treatment system.

DOT National Transportation Integrated Search

2000-07-01

In November of 1996 an interstate rest area was opened on I-49, approximately 20 miles north of Opelousas, Louisiana. Wastewater generated in the main building as well as that from an RV dump station is treated using subsurface flow, rock plant filte...

PASSIVE TREATMENT OF ACID ROCK DRAINAGE FROM A SUBSURFACE MINE

EPA Science Inventory

Acidic, metal-contaminated drainages are a critical problem facing many areas of the world. Acid rock drainage results when metal sulfide minerals, particularly pyrite, are oxidized by exposure to oxygen and water. The deleterious effects of these drainages on receiving streams a...

Composition of the Cayley Formation at Apollo 16 as inferred from impact melt splashes

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Horz, Friedrich; See, Thomas H.

1986-01-01

Abundances of major and trace elements and magnetic properties of 50 impact melt splashes (IMSs) from the Apollo 16 landing site are analzyed to determine the composition of their meteoritic component. MgO-Sc and Ca-Sc variation diagrams and least-squares mixing models are utilized to analyze the IMS, soil, and rock data. Consideration is given to progenitor lithologies of the IMS, the number of impact events represented by the IMS, and the heterogeneity of impact melts from single events. It is observed that the IMSs are composed of either a mixture of anorthosite and low-Sc impact melt rocks or anorthositic norite. It is determined that the surface Cayley layer is composed of TiO2, MgO, Sc, and La concentrations of 0.69, and 7.1 wt pct and 10.5 and 21.2 microg/g, respectively and 0.38 and 5.9 wt pct and 6.1 and 11.8 microg/g, respectively, for the subsurface Cayley layer. The Descartes Formation composition is estimated as TiO2, MgO, Sc, and La concentrations of 0.25, and 3.5 wt pct and 7.7 and 2.2 microg/g, respectively.

Element mobilization and immobilization from carbonate rocks between CO 2 storage reservoirs and the overlying aquifers during a potential CO 2 leakage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawter, Amanda R.; Qafoku, Nikolla P.; Asmussen, R. Matthew

Despite the numerous studies on changes within the reservoir following CO2 injection and the effects of CO2 release into overlying aquifers, little or no literature is available on the effect of CO2 release on rock between the storage reservoirs and subsurface. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in this intermediate zone. After rocks reacted with CO2, liquid analysis showed an increase of major elements (e.g., Ca, and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower concentrations were observed in N2 controls. In experimentsmore » with As/Cd and/or organic spikes, representing potential contaminants in the CO2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO2-reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO2-laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation.« less

Subsurface temperatures and surface heat flow in the Michigan Basin and their relationships to regional subsurface fluid movement

USGS Publications Warehouse

Vugrinovich, R.

1989-01-01

Linear regression of 405 bottomhole temperature (BHT) measurements vs. associated depths from Michigan's Lower Peninsula results in the following equation relating BHT and depth: BHT(??C) = 14.5 + 0.0192 ?? depth(m) Temperature residuals, defined as (BHT measured)-(BHT calculated), were determined for each of the 405 BHT's. Areas of positive temperature residuals correspond to areas of regional groundwater discharge (determined from maps of equipotential surface) while areas of negative temperature residuals correspond to areas of regional groundwater recharge. These relationships are observed in the principal aquifers in rocks of Devonian and Ordovician age and in a portion of the principal aquifer in rocks of Silurian age. There is a similar correspondence between high surface heat flow (determined using the silica geothermometer) and regional groundwater discharge areas and low surface heat flow and regional groundwater recharge areas. Post-Jurassic depositional and tectonic histories suggest that the observed coupling of subsurface temperature and groundwater flow systems may have persisted since Jurassic time. Thus the higher subsurface palaeotemperatures (and palaeogeothermal gradients) indicated by recent studies most likely pre-date the Jurassic. ?? 1989.

Tailings Pond Characterization And Designing Through Geophysical Surveys In Dipping Sedimentary Formations

NASA Astrophysics Data System (ADS)

Muralidharan, D.; Andrade, R.; Anand, K.; Sathish, R.; Goud, K.

2009-12-01

Mining activities results into generation of disintegrated waste materials attaining increased mobilization status and requires a safe disposal mechanism through back filling process or secluded storage on surface with prevention of its interaction with environment cycle. The surface disposal of waste materials will become more critical in case of mined minerals having toxic or radioactive elements. In such cases, the surface disposal site is to be characterized for its sub-surface nature to understand its role in environmental impact due to the loading of waste materials. Near surface geophysics plays a major role in mapping the geophysical characters of the sub-surface formations in and around the disposal site and even to certain extent helps in designing of the storage structure. Integrated geophysical methods involving resistivity tomography, ground magnetic and shallow seismic studies were carried out over proposed tailings pond area of 0.3 sq. kms underlined by dipping sedimentary rocks consisting of ferruginous shales and dolomitic to siliceous limestone with varying thicknesses. The investigated site being located in tectonically disturbed area, geophysical investigations were carried out with number of profiles to visualize the sub-surface nature with clarity. The integration of results of twenty profiles of resistivity tomography with 2 m (shallow) and 10 m (moderate depth) electrode spacing’s enabled in preparing probable sub-surface geological section along the strike direction of the formation under the tailings pond with some geo-tectonic structure inferred to be a fault. Similarly, two resistivity tomography profiles perpendicular to the strike direction of the formations brought out the existence of buried basic intrusive body on the northern boundary of the proposed tailings pond. Two resistivity tomography profiles in criss-cross direction over the suspected fault zone confirmed fault existence on the north-eastern part of tailings pond. Thirty two magnetic profiles inside the tailings pond and surrounding areas on the southern part of the tailings pond enabled in identifying two parallel east-west intrusive bodies forming the impermeable boundary for the tailings pond. The shallow seismic refraction and the geophysical studies in and around the proposed tailings pond brought out the suitability of the site, even when the toxic elements percolates through the subsurface formations in to the groundwater system, the existence of dykes on either side of the proposed ponding area won’t allow the water to move across them thus by restricting the contamination within the tailings pond area. Similarly, the delineation of a fault zone within the tailings pond area helped in shifting the proposed dam axis of the pond to avoid leakage through the fault zone causing concern to environment pollution.

Fourier transform infrared spectral detection of life in polar subsurface environments and its application to Mars exploration.

PubMed

Preston, Louisa J; Johnson, Diane; Cockell, Charles S; Grady, Monica M

2015-09-01

Cryptoendolithic lichen communities of the Dry Valleys, Antarctica, survive in an extremely inhospitable environment, finding refuge in microscopic niches where conditions suitable for life exist. Such "within-rock" communities may have evolved on Mars when conditions for life on the surface deteriorated to such an extent that they could no longer survive. Fourier transform infrared spectroscopy of unprepared whole-rock Antarctic Beacon sandstones was used to vertically profile molecular vibrations of fatty acids, proteins, and carboxylic acids created by endolithic communities. Spectral biosignatures were found localized to lichen-rich areas and were absent in crustal regions and the bulk rock substrate. These cryptoendolithic profiles will aid similar spectroscopic investigations of organic biosignatures during future Martian subsurface studies and will help in the identification of similar communities in other localities across the Earth.

A study of surface and subsurface ground motions at Calico Hills, Nevada Test Site

USGS Publications Warehouse

King, Kenneth W.

1982-01-01

A study of earthquake ground motions recorded at depth in a drill hole and at the ground surface has derived the surface to subsurface transfer functions such as might be expected at a potential nuclear waste repository in a similar setting. The site under investigation has small seismic velocity contrasts in the layers of rock between the surface and the subsurface seismometer location. The subsurface seismic motions were similar in spectral characteristics to the surface motions and were lower in amplitude across the recorded band-width by a factor of 1.5.

The Jettencave, Southern Harz Mountains, Germany: Geophysical observations and a structural model of a shallow cave in gypsum/anhydrite-bearing rocks

NASA Astrophysics Data System (ADS)

Kaufmann, Georg; Romanov, Douchko

2017-12-01

Gypsum and anhydrite are soluble rocks, where fissures and bedding partings can be enlarged with time by the dissolution of the mineral species through water. The selective enlargement results in sub-surface voids acting as preferential flow path for the drainage of the rock. With time, larger cavities develop, and a network of cave passages can evolve. If the enlarged cave voids are not too deep under the surface, geophysical measurements can be used to detect, identify and trace these structures. We have used gravity measurements (GRAV), electrical resistivity imaging (ERI), self-potential measurements (SP), electrical conductivity measurements (EC), and ground-penetrating radar (GPR) above the cave Jettenhöhle, a cave located in the southern Harz Mountains in Germany. The Jettencave is developed in the Hauptanhydrit formation of the Permian Zechstein sequence, characterised by large breakdown rooms and an exposed water table. The overburden of the cave is only around 10-15 m, and dolomitic rocks are located in close vicinity. We present results from our geophysical surveys in vicinity of the cave. We are able to identify the cave geometry from GRAV, ERI, and GPR measurements, which distinguish the local lithology of the Permian Zechstein rocks in the area. From the ERI and EC measurements, we derive information on the void volume in the soluble rocks. We finally present a three-dimensional structural model of the Jettencave and its surroundings, based on our geophysical results and the hydrological interpretation.

Structural Analysis: Folds Classification of metasedimentary rock in the Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Shamsuddin, A.

2017-10-01

Understanding shear zone characteristics of deformation are a crucial part in the oil and gas industry as it might increase the knowledge of the fracture characteristics and lead to the prediction of the location of fracture zones or fracture swarms. This zone might give high influence on reservoir performance. There are four general types of shear zones which are brittle, ductile, semibrittle and brittle-ductile transition zones. The objective of this study is to study and observe the structural geometry of the shear zones and its implication as there is a lack of understanding, especially in the subsurface area because of the limitation of seismic resolution. A field study was conducted on the metasedimentary rocks (shear zone) which are exposed along the coastal part of the Peninsular Malaysia as this type of rock resembles the types of rock in the subsurface. The analysis in this area shows three main types of rock which are non-foliated metaquartzite and foliated rock which can be divided into slate and phyllite. Two different fold classification can be determined in this study. Layer 1 with phyllite as the main type of rock can be classified in class 1C and layer 2 with slate as the main type of rock can be classified in class 1A. This study will benefit in predicting the characteristics of the fracture and fracture zones.

Geophysical Characterization of Subsurface Properties Relevant to the Hydrology of the Standard Mine in Elk Basin, Colorado

USGS Publications Warehouse

Minsley, Burke J.; Ball, Lyndsay B.; Burton, Bethany L.; Caine, Jonathan S.; Curry-Elrod, Erika; Manning, Andrew H.

2010-01-01

Geophysical data were collected at the Standard Mine in Elk Basin near Crested Butte, Colorado, to help improve the U.S. Environmental Protection Agency's understanding of the hydrogeologic controls in the basin and how they affect surface and groundwater interactions with nearby mine workings. These data are discussed in the context of geologic observations at the site, the details of which are provided in a separate report. This integrated approach uses the geologic observations to help constrain subsurface information obtained from the analysis of surface geophysical measurements, which is a critical step toward using the geophysical data in a meaningful hydrogeologic framework. This approach combines the benefit of many direct but sparse field observations with spatially continuous but indirect measurements of physical properties through the use of geophysics. Surface geophysical data include: (1) electrical resistivity profiles aimed at imaging variability in subsurface structures and fluid content; (2) self-potentials, which are sensitive to mineralized zones at this site and, to a lesser extent, shallow-flow patterns; and (3) magnetic measurements, which provide information on lateral variability in near-surface geologic features, although there are few magnetic minerals in the rocks at this site. Results from the resistivity data indicate a general two-layer model in which an upper highly resistive unit, 3 to 10 meters thick, overlies a less resistive unit that is imaged to depths of 20 to 25 meters. The high resistivity of the upper unit likely is attributed to unsaturated conditions, meaning that the contact between the upper and lower units may correspond to the water table. Significant lateral heterogeneity is observed because of the presence of major features such as the Standard and Elk fault veins, as well as highly heterogeneous joint distributions. Very high resistivities (greater than 10 kiloohmmeters) are observed in locations that may correspond to more silicified, lower porosity rock. Several thin (2 to 3 meters deep and up to tens of meters wide) low-resistivity features in the very near surface coincide with observed surface-water drainage features at the site. These are limited to depths less than 3 meters and may indicate surface and very shallow groundwater flowing downhill on top of less permeable bedrock. The data do not clearly point to discrete zones of high infiltration, but these cannot be ruled out given the heterogeneous nature of joints in the shallow subsurface. Disseminated and localized electrically conductive mineralization do not appear to play a strong role in controlling the resistivity values, which generally are high throughout the site. The self-potential analysis highlights the Standard fault vein, the northwest (NW) Elk vein near the Elk portal, and several polymetallic quartz veins. These features contain sulfide minerals in the subsurface that form an electrochemical cell that produces their distinct self-potential signal. A smaller component of the self-potential signal is attributed to relatively moderate topographically driven shallow groundwater flow, which is most prevalent in the vicinity of Elk Creek and to a lesser extent in the area of surface-water drainage below the Level 5 portal. Given the anomalies associated with the electrochemical weathering near the Standard fault vein, it is not possible to completely rule out downward infiltration of surface water and shallow groundwater intersected by the fault, though this is an unlikely scenario given the available data. Magnetic data show little variation, consistent with the mostly nonmagnetic host rocks and mineralization at the site, which is verified by magnetic susceptibility measurements and X-ray diffraction mineralogy data on local rock samples. The contact between the Ohio Creek Member of the Mesaverde Formation and Wasatch Formation coincides with a change in character of the magnetic signature, though

Climate Implications of an Ancient Lake Basin in Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Vasavada, A. R.; Arvidson, R. E.; Edgett, K. S.; Fairén, A. G.; Fedo, C.; Grotzinger, J. P.; Gupta, S.; House, C. H.; Lewis, K. W.; Rivera-Hernandez, F.; Wiens, R. C.

2017-12-01

The sedimentary rock record explored in Aeolis Palus and in the lower slopes of Aeolis Mons using the Curiosity rover is interpreted to be that of streams and lakes that persisted for millions of years. Fluvio-deltaic rocks of the Bradbury group, upon which Curiosity landed, are interpreted to interfinger with the Murray formation rocks of lower Aeolis Mons (Mount Sharp). The more than 200 vertical meters of Murray formation section investigated using Curiosity primarily comprise laminated mudstones, with interstratified cross-stratified facies prevalent higher in the succession. These rocks are interpreted as lacustrine with minor fluvial and aeolian intervals. Comparison with depositional rates in terrestrial lake basins suggests that lakes were present within Gale crater for millions of years. Facies diagnostic of seasonal or perennial ice cover, or of ice within the sediment, have not been found, but ice cannot be ruled out. Calculated chemical index of alteration (CIA) values suggest cold and arid conditions in rocks studied on the plains but warmer and more humid conditions in the rocks of lower Aeolis Mons. Evidence of early and late diagenesis, e.g., concretions, calcium sulfate veins, and fracture-adjacent alteration haloes, implies that multiple generations of groundwater (i.e., liquid) interacted with the sediments post-deposition. Crater counts indicate that Gale crater formed at about 3.8-3.6 Ga near the Noachian-Hesperian boundary and that deposition, burial, lithification, and exhumation of the lower section of central mound occurred by 3.3-3.1 Ga. Together, these observations constrain the climate of early Hesperian equatorial Mars to states that permitted liquid water to be thermodynamically stable at the surface and in the subsurface at Gale crater, and that were sufficiently humid to reduce evaporative losses and to drive fluvial erosion, transport, and re-charging of the lakes with a hydrological cycle. Isotopic measurements of atmospheric gases and of water evolved from Hesperian-age clay minerals support models of atmospheric loss in the early history of Mars.

Effects of smectite on the oil-expulsion efficiency of the Kreyenhagen Shale, San Joaquin Basin, California, based on hydrous-pyrolysis experiments

USGS Publications Warehouse

Lewan, Michael D.; Dolan, Michael P.; Curtis, John B.

2014-01-01

The amount of oil that maturing source rocks expel is expressed as their expulsion efficiency, which is usually stated in milligrams of expelled oil per gram of original total organic carbon (TOCO). Oil-expulsion efficiency can be determined by heating thermally immature source rocks in the presence of liquid water (i.e., hydrous pyrolysis) at temperatures between 350°C and 365°C for 72 hr. This pyrolysis method generates oil that is compositionally similar to natural crude oil and expels it by processes operative in the subsurface. Consequently, hydrous pyrolysis provides a means to determine oil-expulsion efficiencies and the rock properties that influence them. Smectite in source rocks has previously been considered to promote oil generation and expulsion and is the focus of this hydrous-pyrolysis study involving a representative sample of smectite-rich source rock from the Eocene Kreyenhagen Shale in the San Joaquin Basin of California. Smectite is the major clay mineral (31 wt. %) in this thermally immature sample, which contains 9.4 wt. % total organic carbon (TOC) comprised of type II kerogen. Compared to other immature source rocks that lack smectite as their major clay mineral, the expulsion efficiency of the Kreyenhagen Shale was significantly lower. The expulsion efficiency of the Kreyenhagen whole rock was reduced 88% compared to that of its isolated kerogen. This significant reduction is attributed to bitumen impregnating the smectite interlayers in addition to the rock matrix. Within the interlayers, much of the bitumen is converted to pyrobitumen through crosslinking instead of oil through thermal cracking. As a result, smectite does not promote oil generation but inhibits it. Bitumen impregnation of the rock matrix and smectite interlayers results in the rock pore system changing from water wet to bitumen wet. This change prevents potassium ion (K+) transfer and dissolution and precipitation reactions needed for the conversion of smectite to illite. As a result, illitization only reaches 35% to 40% at 310°C for 72 hr and remains unchanged to 365°C for 72 hr. Bitumen generation before or during early illitization in these experiments emphasizes the importance of knowing when and to what degree illitization occurs in natural maturation of a smectite-rich source rock to determine its expulsion efficiency. Complete illitization prior to bitumen generation is common for Paleozoic source rocks (e.g., Woodford Shale and Retort Phosphatic Shale Member of the Phosphoria Formation), and expulsion efficiencies can be determined on immature samples by hydrous pyrolysis. Conversely, smectite is more common in Cenozoic source rocks like the Kreyenhagen Shale, and expulsion efficiencies determined by hydrous pyrolysis need to be made on samples that reflect the level of illitization at or near bitumen generation in the subsurface.

Quantifying Biofilm in Porous Media Using Rock Physics Models

NASA Astrophysics Data System (ADS)

Alhadhrami, F. M.; Jaiswal, P.; Atekwana, E. A.

2012-12-01

Biofilm formation and growth in porous rocks can change their material properties such as porosity, permeability which in turn will impact fluid flow. Finding a non-intrusive method to quantify biofilms and their byproducts in rocks is a key to understanding and modeling bioclogging in porous media. Previous geophysical investigations have documented that seismic techniques are sensitive to biofilm growth. These studies pointed to the fact that microbial growth and biofilm formation induces heterogeneity in the seismic properties. Currently there are no rock physics models to explain these observations and to provide quantitative interpretation of the seismic data. Our objectives are to develop a new class of rock physics model that incorporate microbial processes and their effect on seismic properties. Using the assumption that biofilms can grow within pore-spaces or as a layer coating the mineral grains, P-wave velocity (Vp) and S-wave (Vs) velocity models were constructed using travel-time and waveform tomography technique. We used generic rock physics schematics to represent our rock system numerically. We simulated the arrival times as well as waveforms by treating biofilms either as fluid (filling pore spaces) or as part of matrix (coating sand grains). The preliminary results showed that there is a 1% change in Vp and 3% change in Vs when biofilms are represented discrete structures in pore spaces. On the other hand, a 30% change in Vp and 100% change in Vs was observed when biofilm was represented as part of matrix coating sand grains. Therefore, Vp and Vs changes are more rapid when biofilm grows as grain-coating phase. The significant change in Vs associated with biofilms suggests that shear velocity can be used as a diagnostic tool for imaging zones of bioclogging in the subsurface. The results obtained from this study have significant implications for the study of the rheological properties of biofilms in geological media. Other applications include assessing biofilms used as barriers in CO2 sequestration studies as well as assisting in evaluating microbial enhanced oil recovery methods (MEOR), where microorganisms are used to plug highly porous rocks for efficient oil production.

Interpretation of Gravimetric and Aeromagnetic Data of the Tecoripa Chart in Southeast Sonora, Mexico.

NASA Astrophysics Data System (ADS)

Martínez-Retama, S.; Montaño-Del Cid, M. A.

2015-12-01

The Tecoripa chart H12-D64 is located southeast of the state of Sonora, México, south of Arizona. The geology is represented by sedimentary rocks of the Ordovician and Triassic, volcanic rocks of the Upper Cretaceous and Tertiary, intrusive rocks from the Upper Cretaceous- Tertiary and sedimentary rocks of the Cenozoic. In this paper a gravimetric study was conducted to determine the configuration and depth of the basement and to develop a structural model of the subsurface. For this purpose a consistent gravimetric survey in 3 profiles was conducted. To complement this study, gravimetric data obtained by INEGI (96 gravimetric stations spaced every 4000 m) that correspond to a regional survey was also used. The two sets of data were corrected and processed with the WinGLink software. The profiles were then modeled using the Talwani method. 4 Profiles corresponding to the gravimetric survey and 5 data profiles from INEGI were modeled. Aeromagnetic data from the total field of Tecoripa chart were also processed. The digital information was integrated and processed by generating a data grid. Processes applied to data consisted of reduction to the pole, regional-residual separation and upward continuations. In general, the obtained structural models show intrusive bodies associated with well-defined high gravimetric and magnetic and low gravimetric and magnetic are associated with basins and sedimentary rocks. The obtained geological models show the basement represented by volcanic rocks of the Tarahumara Formation from the Upper Cretaceous which are in contact with sedimentary rocks from the Barranca Group from Upper Cretaceous and limestones from the Middle Ordovician. Both volcanic and sedimentary rocks are intruded by granodiorite- granite with ages of the Tertiary-Oligocene. Based on the superficial geology as well as in the configuration of the basement and the obtained structural model the existence of faults with NW-SE orientation that originate Horst and Graben type structures can be inferred. The basins have depths of 2,000 to 4,000m with sedimentary fillings from the Báucarit Formation and Quaternary sediments.

In-situ GPR test for three-dimensional mapping of the dielectric constant in a rock mass

NASA Astrophysics Data System (ADS)

Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Papeschi, Paolo; Bonduà, Stefano; Bruno, Roberto

2017-11-01

The Ground Penetrating Radar (GPR) is used to detect subsurface anomalies in several applications. The more the velocity of propagation or the dielectric constant is estimated accurately, the more the detection of anomalies at true subsurface depth can be accurately obtained. Since many GPR applications are performed in rock mass with non-homogeneous discontinuous nature, errors in estimating a bulk velocity of propagation or dielectric constant are possible. This paper presents a new in-situ GPR test for mapping the dielectric constant variability in a rock mass. The main aim is to investigate to what extent the dielectric constant is variable in the micro and macro scale of a typical rock mass and to give attention to GPR users in rock mass mediums. The methodology of this research is based on the insertion of steel rods in a rock mass, thus acting as reflectors. The velocity of propagation can be then modeled, from hyperbolic reflections, in the form of velocity pathways from antenna positions to a buried rod. Each pathway is characterized by discrete points which are assumed in three dimensions as centers of micro cubic rock mass. This allows converting the velocity of propagation into a dielectric constant for mapping and modeling the dielectric constant in a volumetric rock mass using a volumetric data visualization software program (Voxler). In a case study, 6 steel drilling rods were diagonally inserted in a vertical face of a bench in a sandstone quarry. Five equally spaced parallel lines, almost perpendicular to the orientations of the rods, were surveyed by a dual frequency GPR antenna of 200 and 600 MHz. The results show that the dielectric constant is randomly varied within the micro and macro scale either in single radargrams or in the volumetric rock mass. The proposed method can be useful if considered in signal processing software programs, particularly in presence of subsurface utilities with known geometry and dimension, allowing converting double travel time, through portions of a radargram, into more reliable depths using discrete dielectric constant values instead of one value for a whole radargram.

Subsurface characterization by the ground penetrating radar WISDOM/ExoMars 2020

NASA Astrophysics Data System (ADS)

Hervé, Y.; Ciarletti, V.; Le Gall, A. A.; Oudart, N.; Loizeau, D.; Guiffaut, C.; Dorizon, S.

2017-12-01

The main objective of the ExoMars 2020 mission is to search for signs of past and/or present life on Mars. Toward this goal, a rover was designed to investigate the shallow subsurface which is the most likely place where signs of life may be preserved, beneath the hostile surface of Mars. The rover of the ExoMars 2020 mission has on board a polarimetric ground penetrating radar called WISDOM (Water Ice Subsurface Deposits Observation on Mars). Thanks to its large frequency bandwidth of 2.5 GHz, WISDOM is able to probe down to a depth of approximately 3 m on sedimentary rock with a vertical resolution of a few centimeters.The main scientific objectives of WISDOM are to characterize the shallow subsurface of Mars, to help understand the local geological context and to identify the most promising location for drilling. The WISDOM team is currently working on the preparation of the scientific return of the ExoMars 2020 mission. In particular, tools are developed to interpret WISDOM experimental data and, more specifically, to extract information from the radar signatures of expected buried reflectors. Insights into the composition of the ground (through the retrieval of its permittivity) and the geological context of the site can be inferred from the radar signature of buried rocks since the shape and the density of rocks in the subsurface is related to the geological processes that have shaped and placed them there (impact, fluvial processes, volcanism). This paper presents results obtained by automatic detection of structures of interest on a radargram, especially radar signature of buried rocks. The algorithm we developed uses a neural network to identify the position of buried rocks/blocs and then a Hough transform to characterize each signature and to estimate the local permittivity of the medium. Firstly, we will test the performances of the algorithm on simulated data constructed with a 3D FDTD code. This code allows us to simulate radar operation in realistic environments. Secondly, we will test our algorithm on experimental data acquired in a semi-controlled environment. Lastly, we will present experimental data acquired during a recent field campaign (July 2017) in the south of France and we will validate our method and illustrate the ability of WISDOM to provide clues about the geological context of a site.

Exploration of a Subsurface Biosphere in a Volcanic Massive Sulfide: Results of the Mars Analog Rio Tinto Drilling Experiment

NASA Astrophysics Data System (ADS)

Stoker, C. R.; Stevens, T.; Amils, R.; Fernandez, D.

2005-12-01

Biological systems on Earth require three key ingredients-- liquid water, an energy source, and a carbon source, that are found in very few extraterrestrial environments. Previous examples of independent subsurface ecosystems have been found only in basalt aquifers. Such lithotrophic microbial ecosystems (LME) have been proposed as models for steps in the early evolution of Earth's biosphere and for potential biospheres on other planets where the surface is uninhabitable, such as Mars and Europa.. The Mars Analog Rio Tinto Experiment (MARTE) has searched in a volcanic massive sulfide deposit in Rio Tinto Spain for a subsurface biosphere capable of living without sunlight or oxygen and found a subsurface ecosystem driven by the weathering of the massive sulfide deposit (VMS) in which the rock matrix provides sufficient resources to support microbial metabolism, including the vigorous production of H2 by water-rock interactions. Microbial production of methane and sulfate occurred in the sulfide orebody and microbial production of methane and hydrogen sulfide continued in an anoxic plume downgradient from the sulfide ore. Organic carbon concentrations in the parent rock were too low to support microbes. The Rio Tinto system thus represents a new type of subsurface ecosystem with strong relevance for exobiological studies. Commercial drilling was used to reach the aquifer system at 100 m depth and conventional laboratory techniques were used to identify and characterize the biosphere. Then, the life search strategy that led to successful identification of this biosphere was applied to the development of a robotic drilling, core handling, inspection, subsampling, and life detection system built on a prototype planetary lander that was deployed in Rio Tinto Spain in September 2005 to test the capability of a robotic drilling system to search for subsurface life. A remote science team directed the simulation and analyzed the data from the MARTE robotic drill. The results of this experiment have important implications for the strategy for searching for life on Mars.

Detection and cultivation of indigenous microorganisms in Mesozoic claystone core samples from the Opalinus Clay Formation (Mont Terri Rock Laboratory)

NASA Astrophysics Data System (ADS)

Mauclaire, L.; McKenzie, J. A.; Schwyn, B.; Bossart, P.

Although microorganisms have been isolated from various deep-subsurface environments, the persistence of microbial activity in claystones buried to great depths and on geological time scales has been poorly studied. The presence of in-situ microbial life in the Opalinus Clay Formation (Mesozoic claystone, 170 million years old) at the Mont Terri Rock Laboratory, Canton Jura, Switzerland was investigated. Opalinus Clay is a host rock candidate for a radioactive waste repository. Particle tracer tests demonstrated the uncontaminated nature of the cored samples, showing their suitability for microbiological investigations. To determine whether microorganisms are a consistent and characteristic component of the Opalinus Clay Formation, two approaches were used: (i) the cultivation of indigenous micoorganisms focusing mainly on the cultivation of sulfate-reducing bacteria, and (ii) the direct detection of molecular biomarkers of bacteria. The goal of the first set of experiments was to assess the presence of cultivable microorganisms within the Opalinus Clay Formation. After few months of incubation, the number of cell ranged from 0.1 to 2 × 10 3 cells ml -1 media. The microorganisms were actively growing as confirmed by the observation of dividing cells, and detection of traces of sulfide. To avoid cultivation bias, quantification of molecular biomarkers (phospholipid fatty acids) was used to assess the presence of autochthonous microorganisms. These molecules are good indicators of the presence of living cells. The Opalinus Clay contained on average 64 ng of PLFA g -1 dry claystone. The detected microbial community comprises mainly Gram-negative anaerobic bacteria as indicated by the ratio of iso/anteiso phospholipids (about 2) and the detection of large amount of β-hydroxy substituted fatty acids. The PLFA composition reveals the presence of specific functional groups of microorganisms in particular sulfate-reducing bacteria ( Desulfovibrio, Desulfobulbus, and Desulfobacter). This study demonstrates that microorganisms are a characteristic component of the unperturbed Opalinus Clay Formation.

Characterization of seismic properties across scales: from the laboratory- to the field scale

NASA Astrophysics Data System (ADS)

Grab, Melchior; Quintal, Beatriz; Caspari, Eva; Maurer, Hansruedi; Greenhalgh, Stewart

2016-04-01

When exploring geothermal systems, the main interest is on factors controlling the efficiency of the heat exchanger. This includes the energy state of the pore fluids and the presence of permeable structures building part of the fluid transport system. Seismic methods are amongst the most common exploration techniques to image the deep subsurface in order to evaluate such a geothermal heat exchanger. They make use of the fact that a seismic wave caries information on the properties of the rocks in the subsurface through which it passes. This enables the derivation of the stiffness and the density of the host rock from the seismic velocities. Moreover, it is well-known that the seismic waveforms are modulated while propagating trough the subsurface by visco-elastic effects due to wave induced fluid flow, hence, delivering information about the fluids in the rock's pore space. To constrain the interpretation of seismic data, that is, to link seismic properties with the fluid state and host rock permeability, it is common practice to measure the rock properties of small rock specimens in the laboratory under in-situ conditions. However, in magmatic geothermal systems or in systems situated in the crystalline basement, the host rock is often highly impermeable and fluid transport predominately takes place in fracture networks, consisting of fractures larger than the rock samples investigated in the laboratory. Therefore, laboratory experiments only provide the properties of relatively intact rock and an up-scaling procedure is required to characterize the seismic properties of large rock volumes containing fractures and fracture networks and to study the effects of fluids in such fractured rock. We present a technique to parameterize fractured rock volumes as typically encountered in Icelandic magmatic geothermal systems, by combining laboratory experiments with effective medium calculations. The resulting models can be used to calculate the frequency-dependent bulk modulus K(ω) and shear modulus G(ω), from which the P- and S-wave velocities V P(ω) and V S(ω) and the quality factors QP(ω) and QS(ω) of fluid saturated fractured rock volumes can be estimated. These volumes are much larger and contain more complex structures than the rock samples investigated in the laboratory. Thus, the derived quantities describe the elastic and anelastic (energy loss due to wave induced fluid flow) short-term deformation induced by seismic waves at scales that are relevant for field-scale seismic exploration projects.

Qtracer Program for Tracer-Breakthrough Curve Analysis for Karst and Fractured-Rock Aquifers (2000)

EPA Science Inventory

Tracer tests are generally regarded as being the most reliable and efficient means of gathering subsurface hydraulic information. This is true for all types of aquifers, but especially so for karst and fractured-rock aquifers. Qualitative tracing tests have been conventionally em...

Enhanced groundwater recharge rates and altered recharge sensitivity to climate variability through subsurface heterogeneity

PubMed Central

Hartmann, Andreas; Gleeson, Tom; Wagener, Thorsten

2017-01-01

Our environment is heterogeneous. In hydrological sciences, the heterogeneity of subsurface properties, such as hydraulic conductivities or porosities, exerts an important control on water balance. This notably includes groundwater recharge, which is an important variable for efficient and sustainable groundwater resources management. Current large-scale hydrological models do not adequately consider this subsurface heterogeneity. Here we show that regions with strong subsurface heterogeneity have enhanced present and future recharge rates due to a different sensitivity of recharge to climate variability compared with regions with homogeneous subsurface properties. Our study domain comprises the carbonate rock regions of Europe, Northern Africa, and the Middle East, which cover ∼25% of the total land area. We compare the simulations of two large-scale hydrological models, one of them accounting for subsurface heterogeneity. Carbonate rock regions strongly exhibit “karstification,” which is known to produce particularly strong subsurface heterogeneity. Aquifers from these regions contribute up to half of the drinking water supply for some European countries. Our results suggest that water management for these regions cannot rely on most of the presently available projections of groundwater recharge because spatially variable storages and spatial concentration of recharge result in actual recharge rates that are up to four times larger for present conditions and changes up to five times larger for potential future conditions than previously estimated. These differences in recharge rates for strongly heterogeneous regions suggest a need for groundwater management strategies that are adapted to the fast transit of water from the surface to the aquifers. PMID:28242703

The Serpentinite Subsurface Microbiome

NASA Astrophysics Data System (ADS)

Schrenk, M. O.; Nelson, B. Y.; Brazelton, W. J.

2011-12-01

Microbial habitats hosted in ultramafic rocks constitute substantial, globally-distributed portions of the subsurface biosphere, occurring both on the continents and beneath the seafloor. The aqueous alteration of ultramafics, in a process known as serpentinization, creates energy rich, high pH conditions, with low concentrations of inorganic carbon which place fundamental constraints upon microbial metabolism and physiology. Despite their importance, very few studies have attempted to directly access and quantify microbial activities and distributions in the serpentinite subsurface microbiome. We have initiated microbiological studies of subsurface seeps and rocks at three separate continental sites of serpentinization in Newfoundland, Italy, and California and compared these results to previous analyses of the Lost City field, near the Mid-Atlantic Ridge. In all cases, microbial cell densities in seep fluids are extremely low, ranging from approximately 100,000 to less than 1,000 cells per milliliter. Culture-independent analyses of 16S rRNA genes revealed low-diversity microbial communities related to Gram-positive Firmicutes and hydrogen-oxidizing bacteria. Interestingly, unlike Lost City, there has been little evidence for significant archaeal populations in the continental subsurface to date. Culturing studies at the sites yielded numerous alkaliphilic isolates on nutrient-rich agar and putative iron-reducing bacteria in anaerobic incubations, many of which are related to known alkaliphilic and subsurface isolates. Finally, metagenomic data reinforce the culturing results, indicating the presence of genes associated with organotrophy, hydrogen oxidation, and iron reduction in seep fluid samples. Our data provide insight into the lifestyles of serpentinite subsurface microbial populations and targets for future quantitative exploration using both biochemical and geochemical approaches.

Enhanced Groundwater Recharge Rates and Altered Recharge Sensitivity to Climate Variability Through Subsurface Heterogeneity

NASA Technical Reports Server (NTRS)

Hartmann, Andreas; Gleeson, Tom; Wada, Yoshihide; Wagener, Thorsten

2017-01-01

Our environment is heterogeneous. In hydrological sciences, the heterogeneity of subsurface properties, such as hydraulic conductivities or porosities, exerts an important control on water balance. This notably includes groundwater recharge, which is an important variable for efficient and sustainable groundwater resources management. Current large-scale hydrological models do not adequately consider this subsurface heterogeneity. Here we show that regions with strong subsurface heterogeneity have enhanced present and future recharge rates due to a different sensitivity of recharge to climate variability compared with regions with homogeneous subsurface properties. Our study domain comprises the carbonate rock regions of Europe, Northern Africa, and the Middle East, which cover 25 of the total land area. We compare the simulations of two large-scale hydrological models, one of them accounting for subsurface heterogeneity. Carbonate rock regions strongly exhibit karstification, which is known to produce particularly strong subsurface heterogeneity. Aquifers from these regions contribute up to half of the drinking water supply for some European countries. Our results suggest that water management for these regions cannot rely on most of the presently available projections of groundwater recharge because spatially variable storages and spatial concentration of recharge result in actual recharge rates that are up to four times larger for present conditions and changes up to five times larger for potential future conditions than previously estimated. These differences in recharge rates for strongly heterogeneous regions suggest a need for groundwater management strategies that are adapted to the fast transit of water from the surface to the aquifers.

Serpentinite Carbonation in the Pollino Massif (southern Italy) for CO2 Sequestration

NASA Astrophysics Data System (ADS)

Carmela Dichicco, Maria; Mongelli, Giovanni; Paternoster, Michele; Rizzo, Giovanna

2015-04-01

Anthropogenic gas emissions are projected to change future climates with potentially nontrivial impacts (Keller et al., 2008 and references therein) and the impacts of the increased CO2 concentration are, among others, the greenhouse effect, the acidification of the surface of the ocean and the fertilization of ecosystems (e.g. Huijgen and Comans, 2003). Geologic Sequestration into subsurface rock formations for long-term storage is part of a process frequently referred to as "carbon capture and storage" or CCS. A major strategy for the in situ geological sequestration of CO2 involves the reaction of CO2 with Mg-silicates, especially in the form of serpentinites, which are rocks: i) relatively abundant and widely distributed in the Earth's crust, and ii) thermodynamically convenient for the formation of Mg-carbonates (e.g., Brown et al., 2011). In nature, carbonate minerals can form during serpentinization or during hydrothermal carbonation and weathering of serpentinites whereas industrial mineral carbonation processes are commonly represented by the reaction of olivine or serpentine with CO2 to form magnesite + quartz ± H2O (Power et al., 2013). Mineral carbonation occurs naturally in the subsurface as a result of fluid-rock interactions within serpentinite, which occur during serpentinization and carbonate alteration. In situ carbonation aims to promote these reactions by injecting CO2 into porous, subsurface geological formations, such as serpentinite-hosted aquifers. In the northern sector of the Pollino Massif (southern Italy) extensively occur serpentinites (Sansone et. al., 2012) and serpentinite-hosted aquifers (Margiotta et al., 2012); both serpentinites and serpentinite-hosted aquifers are the subject of a comprehensive project devoted to their possible use for in situ geological sequestration of CO2. The serpentinites derived from a lherzolitic and subordinately harzburgitic mantle, and are within tectonic slices in association with metadolerite dykes and medium to high-grade metamorphic rocks. Primary mantle minerals are olivine, clinopyroxene, orthopyroxene, and spinel whereas serpentine, magnetite, chlorite, and amphibole are pseudomorphic minerals. Olivine is replaced by serpentine forming a mesh texture and orthopyroxene is mostly altered to bastite. Water chemistry indicates serpentinites interact with meteoric water producing a Mg-HCO3 type water in a system open to CO2. Brown Jr., G.E., Calas, G., (2011) - Environmental mineralogy - understanding element behavior in ecosystems. Comptes Rendus Geoscience 343, 90-112. Huijgen W.JJ., and Comans R.N.J., (2003) - Carbon dioxide sequestrationby mineral carbonation. Report Number ECN-C-03-016, Energy research Centre of the Netherlands (ECN), Petten, the Netherlands. Keller PJ, Schmidt AD, Wittbrodt J, Stelzer EHK. (2008) - Reconstruction of zebrafish early embryonic development by scanned light sheet microscopy. Science 322: 1065-1069. Margiotta, S., Mongelli, G., Summa, V., Paternoster, M., Fiore S. (2012) - Trace element distribution and Cr(VI) speciation in Ca-HCO3 and Mg-HCO3 spring waters from the northern sector of the Pollino massif, southern Italy. Journal of Geochemical Exploration. Power I.M., Wilson S.A., Dipple G.M. (2013) - Serpentinite Carbonation for CO2 Sequestration. Elements, 9, 115-121. Sansone M.T.C., Prosser G., Rizzo G., Tartarotti P. (2012) - Spinel-peridotites of the Frido Unit ophiolites: evidence for oceanic evolution. Periodico di Mineralogia. 81, 35-59. 10.2451/2012PM0003

Abiotic vs biological sources and fates of organic compounds in a low temperature continental serpentinizing system

NASA Astrophysics Data System (ADS)

Robinson, K.; Noble, S. M.; Shock, E.

2016-12-01

Serpentinization is likely the most common water-rock reaction in our solar system. During this process ultramafic silicates are hydrated, a calcium hydroxide solution is formed, and H2O is reduced to H2 coupled to the oxidation of Fe2+ to Fe3+. The resulting hyper-alkaline, reduced conditions generate thermodynamic drives for numerous carbon compound reactions, including the precipitation of various carbonate minerals and the reduction of inorganic carbonate to organic carbon. Testing the extent to which these thermodynamic drives lead to observable results led to the present study of the flow and transformations of carbon through the active continental serpentinizing system at the Samail Ophiolite in the Sultanate of Oman. Water samples were collected from shallow groundwater (representing system input), hyper-alkaline seeps (system output), boreholes (system intermediate), and surface fluid mixing zones, and analyzed for concentrations of dissolved inorganic carbon (DIC + δ13C), organic carbon (+ δ13C), formate, acetate, H2, methane (+ δ13C), ethane, and an accompanying suite of other geochemical solutes. These analyses indicate that the vast majority of DIC in these serpentinizing fluids precipitates in the subsurface as carbonate minerals; however, a significant amount of DIC is converted into organic acids and light hydrocarbons and expelled at the surface in hyper-alkaline seeps. Based on thermodynamic calculations, it seems most likely that formate last equilibrated with dolomite (CaMg[CO3]2) in the subsurface, acetate last equilibrated with calcite (CaCO3) near the surface, and methane and ethane last equilibrated in a distinct carbon-limited region of the subsurface. As for the fates of these compounds, energetic calculations reveal that a combination of oxidative, reductive, and fermentative metabolisms are thermodynamically favorable. Indeed, δ13C trends record microbial methane oxidation at the surface and cannot rule out methane as biologically sourced from the subsurface.

Fayalite Dissolution and Siderite Formation in Water-Saturated Supercritical CO2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qafoku, Odeta; Kovarik, Libor; Kukkadapu, Ravi K.

2012-11-25

Olivines, a significant constituent of basaltic rocks, have the potential to immobilize permanently CO2 after it is injected in the deep subsurface, due to carbonation reactions occurring between CO2 and the host rock. To investigate the reactions of fayalitic olivine with supercritical CO2 (scCO2) and formation of mineral carbonates, experiments were conducted at temperatures of 35 °C to 80 °C, 90 atm pressure and anoxic conditions. For every temperature, the dissolution of fayalite was examined both in the presence of liquid water and H2O-saturated scCO2. The experiments were conducted in a high pressure batch reactor at reaction time extending upmore » to 85 days. The newly formed products were characterized using a comprehensive suite of bulk and surface characterization techniques X-ray diffraction, Transmission/Emission Mössbauer Spectroscopy, Scanning Electron Microscopy coupled with Focused Ion Beam, and High Resolution Transmission Electron Microscopy. Siderite with rhombohedral morphology was formed at 35 °C, 50 °C, and 80 °C in the presence of liquid water and scCO2. In H2O-saturated scCO2, the formation of siderite was confirmed only at high temperature (80 °C). Characterization of reacted samples in H2O-saturated scCO2 with high resolution TEM indicated that siderite formation initiated inside voids created during the initial steps of fayalite dissolution. Later stages of fayalite dissolution result in the formation of siderite in layered vertical structures, columns or pyramids with a rhombus base morphology.« less

Characterizing Drainage Multiphase Flow in Heterogeneous Sandstones

NASA Astrophysics Data System (ADS)

Jackson, Samuel J.; Agada, Simeon; Reynolds, Catriona A.; Krevor, Samuel

2018-04-01

In this work, we analyze the characterization of drainage multiphase flow properties on heterogeneous rock cores using a rich experimental data set and mm-m scale numerical simulations. Along with routine multiphase flow properties, 3-D submeter scale capillary pressure heterogeneity is characterized by combining experimental observations and numerical calibration, resulting in a 3-D numerical model of the rock core. The uniqueness and predictive capability of the numerical models are evaluated by accurately predicting the experimentally measured relative permeability of N2—DI water and CO2—brine systems in two distinct sandstone rock cores across multiple fractional flow regimes and total flow rates. The numerical models are used to derive equivalent relative permeabilities, which are upscaled functions incorporating the effects of submeter scale capillary pressure. The functions are obtained across capillary numbers which span four orders of magnitude, representative of the range of flow regimes that occur in subsurface CO2 injection. Removal of experimental boundary artifacts allows the derivation of equivalent functions which are characteristic of the continuous subsurface. We also demonstrate how heterogeneities can be reorientated and restructured to efficiently estimate flow properties in rock orientations differing from the original core sample. This analysis shows how combined experimental and numerical characterization of rock samples can be used to derive equivalent flow properties from heterogeneous rocks.

Changes in bacteria recoverable from subsurface volcanic rock samples during storage at 4{degrees}C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haldeman, D.L.; Amy, P.S.; White, D.C.

1994-08-01

The abundance of viable microorganisms recovered from deep subsurface volcanic rock samples increased after rock perturbation and storage for 1 week at 4{degrees}C, while the diversity and evenness of recoverable heterotrophic bacterial communities generally decreased. One sample of each morphologically distinct colony type, recovered both before and after storage of U12n rock samples, was purified and characterized by fatty acid methyl ester (MIDI) and API rapid NFT strips. As determined by MIDI cluster analysis, the composition of the recoverable microbial communities changed with storage of rock samples; some groups of organisms were recovered only before, only after, or at bothmore » sample times. In general, the isolates recovered only after storage of rock samples had a greater ability to utilize the carbohydrates included in API test strips and had faster generation times than isolates recovered only on initial plating. The nutritional versatility and faster growth rates of organisms recovered in higher proportions after sample storage provide evidence that some microbial community changes may be due to the proliferation of a few bacterial types. However, because some new genera are recovered only after storage, the possibility also exists that dormant bacterial types are resuscitated during sample perturbation and storage. 30 refs., 1 fig., 5 tabs.« less

Evidence for methane in Martian meteorites

PubMed Central

Blamey, Nigel J. F.; Parnell, John; McMahon, Sean; Mark, Darren F.; Tomkinson, Tim; Lee, Martin; Shivak, Jared; Izawa, Matthew R. M.; Banerjee, Neil R.; Flemming, Roberta L.

2015-01-01

The putative occurrence of methane in the Martian atmosphere has had a major influence on the exploration of Mars, especially by the implication of active biology. The occurrence has not been borne out by measurements of atmosphere by the MSL rover Curiosity but, as on Earth, methane on Mars is most likely in the subsurface of the crust. Serpentinization of olivine-bearing rocks, to yield hydrogen that may further react with carbon-bearing species, has been widely invoked as a source of methane on Mars, but this possibility has not hitherto been tested. Here we show that some Martian meteorites, representing basic igneous rocks, liberate a methane-rich volatile component on crushing. The occurrence of methane in Martian rock samples adds strong weight to models whereby any life on Mars is/was likely to be resident in a subsurface habitat, where methane could be a source of energy and carbon for microbial activity. PMID:26079798

Evidence for methane in Martian meteorites.

PubMed

Blamey, Nigel J F; Parnell, John; McMahon, Sean; Mark, Darren F; Tomkinson, Tim; Lee, Martin; Shivak, Jared; Izawa, Matthew R M; Banerjee, Neil R; Flemming, Roberta L

2015-06-16

The putative occurrence of methane in the Martian atmosphere has had a major influence on the exploration of Mars, especially by the implication of active biology. The occurrence has not been borne out by measurements of atmosphere by the MSL rover Curiosity but, as on Earth, methane on Mars is most likely in the subsurface of the crust. Serpentinization of olivine-bearing rocks, to yield hydrogen that may further react with carbon-bearing species, has been widely invoked as a source of methane on Mars, but this possibility has not hitherto been tested. Here we show that some Martian meteorites, representing basic igneous rocks, liberate a methane-rich volatile component on crushing. The occurrence of methane in Martian rock samples adds strong weight to models whereby any life on Mars is/was likely to be resident in a subsurface habitat, where methane could be a source of energy and carbon for microbial activity.

Geology of the undeveloped oil and gas fields of Central Offshore Santa Maria Basin, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milton, J.D.; Edwards, E.B.; Heck, R.G.

1996-01-01

Two prominent subsurface structural features of the Central Offshore Santa Maria Basin are the Hosgri fault system and the associated anticlinal fold trend. Exploratory drilling and 3D seismic mapping have delineated a series of oil and gas fields along this trend which underlie four federal units and one non-unitized lease. The units are named after local geography and are called the Lion Rock, Point Sal, Purisima Point and Santa Maria Units. The individual lease, OCS P-0409, overlies the San Miguel field. The Hosgri fault system trends northwest-southeast and effectively forms the eastern boundary of the oil and gas province. Lyingmore » semi-parallel with the fault are several anticlinal culminations which have trapped large volumes of oil and gas in the fractured Montery Formation. The Monterey is both source and reservoir rock, averaging 300 meters n thickness throughout the Central Basin. Development of the Monterey Formation as a reservoir rock was through diagensis and tectonism with resulting porosities-from 15 to 20% and permeability up to one Darcy. These parameters coupled with a high geothermal gradient facilitate the inflow rates of the viscous Monterey oil. Some 24 exploration and delineation wells have been drilled in this area and tested at rates ranging from a few hundred to several thousand barrels per day. Estimated oil reserves in the Central Offshore Santa Maria Basin total approximately 1 billion barrels.« less

Geology of the undeveloped oil and gas fields of Central Offshore Santa Maria Basin, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milton, J.D.; Edwards, E.B.; Heck, R.G.

1996-12-31

Two prominent subsurface structural features of the Central Offshore Santa Maria Basin are the Hosgri fault system and the associated anticlinal fold trend. Exploratory drilling and 3D seismic mapping have delineated a series of oil and gas fields along this trend which underlie four federal units and one non-unitized lease. The units are named after local geography and are called the Lion Rock, Point Sal, Purisima Point and Santa Maria Units. The individual lease, OCS P-0409, overlies the San Miguel field. The Hosgri fault system trends northwest-southeast and effectively forms the eastern boundary of the oil and gas province. Lyingmore » semi-parallel with the fault are several anticlinal culminations which have trapped large volumes of oil and gas in the fractured Montery Formation. The Monterey is both source and reservoir rock, averaging 300 meters n thickness throughout the Central Basin. Development of the Monterey Formation as a reservoir rock was through diagensis and tectonism with resulting porosities-from 15 to 20% and permeability up to one Darcy. These parameters coupled with a high geothermal gradient facilitate the inflow rates of the viscous Monterey oil. Some 24 exploration and delineation wells have been drilled in this area and tested at rates ranging from a few hundred to several thousand barrels per day. Estimated oil reserves in the Central Offshore Santa Maria Basin total approximately 1 billion barrels.« less

Sequence stratigraphy of the Monterey Formation, Santa Barbara County: Integration of physical, chemical, and biofacies data from outcrop and subsurface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bohacs, K.M.

1990-05-01

Deep basinal rocks of the Monterey Formation can be allocated to different depositional environments based on an integration of bedding, facies stacking patterns, lithology, biofacies, and inorganic and organic chemistry. These rocks show evidence of systematic changes in depositional environments that can be related to eustatic sea level change and basin evolution. Even deep-basinal environments are affected by changing sea level through changes in circulation patterns and intensities nutrient budgets and dispersal patterns, and location and intensity of the oceanic oxygen minimum. The sequence-stratigraphic framework was constructed based on the physical expression of the outcrop strata and confirmed by typingmore » the outcrop sections to an integrated well-log/seismic grid through outcrop gamma-ray-spectral profiles. Interpretation of a sequence boundary was based on increased proportions of hemipelagic facies, evidence of increased bottom-energy levels above the boundary, and local erosion and relief on the surface. The proportion of shallower water and reworked dinoflagellates increased to a local maximum above the boundary, Downlap surfaces exhibited increased proportions of pelagic facies around the surface, evidence of decreased bottom-energy levels and terrigenous sedimentation rates, and little or no significant erosion on the surface. The proportion of deeper water dinoflagellates increased to a local maximum at or near the downlap surface; there was no evidence of reworked individuals. The detailed sequence-stratigraphic framework makes it possible to the rock properties to genetic processes for construction of predictive models.« less

Transport of Organic Contaminants Mobilized from Coal through Sandstone Overlying a Geological Carbon Sequestration Reservoir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Lirong; Cantrell, Kirk J.; Bacon, Diana H.

2014-02-01

Column experiments were conducted using a wetted sandstone rock installed in a tri-axial core holder to study the flow and transport of organic compounds mobilized by scCO2 under simulated geologic carbon storage (GCS) conditions. The sandstone rock was collected from a formation overlying a deep saline reservoir at a GCS demonstration site. Rock core effluent pressures were set at 0, 500, or 1000 psig and the core temperature was set at 20 or 50°C to simulate the transport to different subsurface depths. The concentrations of the organic compounds in the column effluent and their distribution within the sandstone core weremore » monitored. Results indicate that the mobility though the core sample was much higher for BTEX compounds than for naphthalene. Retention of organic compounds from the vapor phase to the core appeared to be primarily controlled by partitioning from the vapor phase to the aqueous phase. Adsorption to the surfaces of the wetted sandstone was also significant for naphthalene. Reduced temperature and elevated pressure resulted in greater partitioning of the mobilized organic contaminants into the water phase.« less

Carbonate Platform Development and Stromatolite Morphogenesis: Constraints on Environmental and Biological Evolution

NASA Technical Reports Server (NTRS)

Grotzinger, John P.

2002-01-01

Work this past year has focused on the globally significant events of faunal turnover, tectonic reorganization, and biogeochemical change that closely coincided with the Precambrian-Cambrian boundary in the Sultanate oilman. Higher temporal and chronostratigraphic resolution are required in order to answer this question. Stratigraphic sections must contain fossils, volcanic rocks, and abundant carbonates with little or no diagenetic overprint. The Ara Group of the South Oman Salt Basin presents such a succession - with carbonate rocks tightly enclosed in a protective envelope of impermeable halite, these rocks have likely never exchanged with younger fluids. Our work has had two thrusts. The first pertains to the geochemistry of the Athel Formation, a deep water deposit formed at the Precambrian-Cambrian boundary which contains unique records of ocean anoxia for that time interval. This unit is important because it will enable tighter focus on the links which existed between global biogeochemical events and episodes of faunal extinction and radiation. The second direction involves a comparison of terminal Proterozoic thrombolites between Oman (subsurface) and Namibia (outcrop). These thrombolites are important not only as significant deposits of ancient microbial communities, but because they formed the key substrate for growth of the oldest calcified metazoans - Cloudina and Namacalathus.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narr, W.; Currie, J.B.

The occurrence of natural fracture systems in subsurface rock can be predicted if careful evaluation is made of the ecologic processes that affect sedimentary strata during their cycle of burial, diagenesis, uplift, and erosional unloading. Variations in the state of stress within rock arise, for example, from changes in temperature, pore pressure, weight of overburden, or tectonic loading. Hence geologic processes acting on a sedimentary unit should be analyzed for their several contributions to the state of stress, and this information used to compute a stress history. From this stress history, predictions may be made as to when in themore » burial cycle to expect fracture (joint) formation, what type of fractures (extension or shear) may occur, and which geologic factors are most favorable to development of fractures. A stress history is computed for strata of the naturally fractured Altamont oil field in Utah's Uinta basin. Calculations suggest that fractures formed in extension, that the well-cemented rocks are those most likely to be fractured, that fractures began to develop only after stata were uplifted and denuded of overburden. Geologic evidence on fracture genesis and development is in accord with the stress history prediction. Stress history can be useful in evaluating a sedimentary basin for naturally fractured reservoir exploration plays.« less

The Impact of Mineralogy on the Geochemical Alteration of Shales During Hydraulic Fracturing Operations

NASA Astrophysics Data System (ADS)

Maher, K.; Harrison, A. L.; Jew, A. D.; Dustin, M. K.; Kiss, A. M.; Kohli, A. H.; Thomas, D.; Joe-Wong, C. M.; Brown, G. E.; Bargar, J.

2016-12-01

The extraction of oil and gas resources from low permeability shale reservoirs using hydraulic fracturing techniques has increased significantly in recent years. During hydraulic fracturing, large volumes of fluid are injected into subsurface shale formations, which drives substantial fluid-rock interaction that can release contaminants and alter rock permeability. Here, a combined experimental, imaging, and modeling approach was employed to systematically evaluate the impact of shale mineralogy on its physical and chemical alteration when exposed to fracturing fluids of different composition. Batch reactor experiments contained different shales with unique mineralogical compositions that were exposed to simulated hydraulic fracturing fluid. Experiments revealed that the balance between fluid acidity and acid neutralizing capacity of the rock was the strongest control on the evolution of fluid and rock chemistry. Carbonate mineral-rich shales rapidly recovered solution pH to circum-neutral conditions, whereas fluids in contact with carbonate mineral-poor shales remained acidic. The dissolution of shale minerals released metal contaminants, yet the precipitation of Fe(III)-bearing secondary phases helped to attenuate their release via co-precipitation or sorption. Post-reaction imaging illustrated that selective dissolution of carbonate minerals generated secondary porosity, the connectivity of which was dictated by initial carbonate distribution. Conversely, the precipitation of secondary Al- and Fe-bearing phases may occlude porosity, potentially inhibiting transport of water, contaminants, and hydrocarbons. The maturation of secondary Fe-bearing phases from amorphous to crystalline over time suggests that porosity will continue to evolve even after oxidation reactions have effectively ceased. These experiments reveal that the relative abundance and distribution of carbonate minerals is the master variable dictating both porosity alteration and contaminant release from shale formations, implying that the response of a reservoir to hydraulic fracturing can be better assessed using robust mineralogical data.

Map showing depth to bedrock in the Seattle 30' by 60' Quadrangle, Washington

USGS Publications Warehouse

Yount, J.C.; Dembroff, G.R.; Barats, G.M.

1985-01-01

Bedrock throughout the Seattle quadrangle is presumed to be volcanic rock, conglomerate, Sandstone, or Shale and is Tertiary in age. With the exception of a few reports of age or lithology collected from oil wells (Livingston, 1958), the subsurface information used for this map sheds little light on the nature and distribution of the various Tertiary rocks in the subsurface. It is assumed, on the basis of pronounced lithologic differences in drill holes and widespread unconformable relationships with underlying bedrock units seen in marine seismic reflection profiles, that the deposits overlying bedrock are Quaternary in age, but no direct dating of materials has been done to confirm this assumption.

Effect of chemical environment and rock composition on fracture mechanics properties of reservoir lithologies in context of CO2 sequestration

NASA Astrophysics Data System (ADS)

Major, J. R.; Eichhubl, P.; Callahan, O. A.

2015-12-01

The coupled chemical and mechanical response of reservoir and seal rocks to injection of CO2 have major implications on the short and long term security of sequestered carbon. Many current numerical models evaluating behavior of reservoirs and seals during and after CO2 injection in the subsurface consider chemistry and mechanics separately and use only simple mechanical stability criteria while ignoring time-dependent failure parameters. CO2 injection irreversibly alters the subsurface chemical environment which can then affect geomechanical properties on a range of time scales by altering rock mineralogy and cements through dissolution, remobilization, and precipitation. It has also been documented that geomechanical parameters such as fracture toughness (KIC) and subcritical index (SCI) are sensitive to chemical environment. Double torsion fracture mechanics testing of reservoir lithologies under controlled environmental conditions relevant to CO2 sequestration show that chemical environment can measurably affect KIC and SCI. This coupled chemical-mechanical behavior is also influenced by rock composition, grains, amount and types of cement, and fabric. Fracture mechanics testing of the Aztec Sandstone, a largely silica-cemented, subarkose sandstone demonstrate it is less sensitive to chemical environment than Entrada Sandstone, a silty, clay-rich sandstone. The presence of de-ionized water lowers KIC by approximately 20% and SCI 30% in the Aztec Sandstone relative to tests performed in air, whereas the Entrada Sandstone shows reductions on the order of 70% and 90%, respectively. These results indicate that rock composition influences the chemical-mechanical response to deformation, and that the relative chemical reactivity of target reservoirs should be recognized in context of CO2 sequestration. In general, inert grains and cements such as quartz will be less sensitive to the changing subsurface environment than carbonates and clays.

Investigating Microbial Biofilm Formations on Crustal Rock Substrates

NASA Astrophysics Data System (ADS)

Weiser, M.; D'Angelo, T.; Carr, S. A.; Orcutt, B.

2017-12-01

Ocean crust hosts microbial life that, in some cases, alter the component rocks as a means of obtaining energy. Variations in crust lithology, included trace metal and mineral content, as well as the chemistry of the fluids circulating through them, provide substrates for some microbes to metabolize, leading to formation of biofilm community structures. Microbes have different parameters for the situations in which they will form biofilms, but they must have some source of energy in excess at the site of biofilm formation for them to become stationary and form the carbohydrate-rich structures connecting the cells to one another and the substrate. Generally, the requirements for microbes to form biofilms on crustal minerals are unclear. We designed two experiments to test (1) mineral preference and biofilm formation rates by natural seawater microbial communities, and (2) biofilm development as a function of phosphate availability for an organism isolated from subseafloor ocean crust. In Experiment 1, we observed that phyric basalt groundmass is preferentially colonized over aphyric basalt or metal sulfides in a shallow water and oxic seawater environment. In experiment 2, tests of the anaerobic heterotroph Thalassospira bacteria isolated from oceanic crustal fluids showed that they preferentially form biofilms, lose motility, and increase exponentially in number over time in higher-PO4 treatments (50 micromolar), including with phosphate-doped basalts, than in treatments with low phosphate concentrations (0.5 micromolar) often found in crustal fluids. These observations suggest phosphate as a main driver of biofilm formation in subsurface crust. Overall, these data suggest that the drivers of microbial biofilm formation on crustal substrates are selective to the substrate conditions, which has important implications for estimating the global biomass of life harbored in oceanic crust.

Heating systems for heating subsurface formations

DOEpatents

Nguyen, Scott Vinh [Houston, TX; Vinegar, Harold J [Bellaire, TX

2011-04-26

Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

Microbial carbon cycling in Lost City hydrothermal chimneys and other serpentinite-hosted ecosystems (Invited)

NASA Astrophysics Data System (ADS)

Brazelton, W. J.; Lang, S. Q.; Morrill, P. L.; Twing, K. I.; Crespo-Medina, M.; Morgan-Smith, D.; Früh-Green, G. L.; Schrenk, M. O.

2013-12-01

Ultramafic rocks formed in the Earth's mantle and uplifted into the crust represent an immense but poorly described reservoir of carbon. The biological availability of this rock-hosted carbon reservoir is unknown, but the set of geochemical reactions known as serpentinization can mobilize carbon from the subsurface and trigger the growth of dense microbial communities. Serpentinite-hosted ecosystems such as the chimney biofilms of the Lost City hydrothermal field can support dense populations of bacteria and archaea fueled by the copious quantities of H2 and methane (CH4) released by serpentinization (1-5). The metabolic pathways involved, however, remain unknown, and conventional interpretations of genomic and experimental data are complicated by the unusual carbon speciation in these environments. Carbon dioxide is scarce due to the highly reducing, high pH conditions. Instead, the predominant forms of carbon are CH4 and formate (5). Despite its natural abundance, however, direct evidence for CH4-derived biomass is lacking (1,4,5), and the role of formate is potentially significant but largely unexplored (1,5). To gain a more generalized perspective of carbon cycling in serpentinite-hosted ecosystems, we have recently investigated fluids and rocks collected from serpentinizing ophiolites in California, Canada, and Italy. Our results point to potentially H2-utilizing, autotrophic Betaproteobacteria thriving in shallow, oxic-anoxic transition zones and anaerobic Clostridia inhabiting anoxic, subsurface zones (1,6). The carbon sources utilized by the Clostridia are unknown, but preliminary metagenomic evidence is consistent with a fermentation-style metabolic strategy that may be conducive to an oxidant-limited, subsurface environment. Curiously, despite the abundance of H2 and CH4 in these continental springs, none of the geochemical, genomic, or experimental results obtained thus far contain any evidence for biological methanogenesis (1,6). This is in stark contrast to the dense populations of methanogen-like archaea in Lost City chimneys. Clearly, the role of methanogens must be constrained in order to gain a firm understanding of the carbon flux from serpentinite ecosystems, and future potential investigations of these systems will be discussed. References 1. Schrenk MO, Brazelton WJ, Lang SQ. 2013. Rev. Mineral. Geochem. 75:575-606. 2. Schrenk MO, Kelley DS, Bolton SA, Baross JA. 2004. Environ. Microbiol. 6:1086-1095. 3. Brazelton WJ, Schrenk MO, Kelley DS, Baross JA. 2006. Appl. Environ. Microbiol. 72:6257-6270. 4. Brazelton WJ, Mehta MP, Kelley DS, Baross JA. 2011. mBio2:4. doi:10.1128/mBio.00127-11. 5. Lang SQ, Früh-Green GL, Bernasconi SM, Lilley MD, Proskurowski G, Méhay S, Butterfield D a. 2012. Geochim. Cosmochim. Acta. 92:82-99. 6. Brazelton WJ, Morrill PL, Szponar N, Schrenk MO. 2013. Appl. Environ. Microbiol. 79:3906.

Sour gas injection for use with in situ heat treatment

DOEpatents

Fowler, Thomas David [Houston, TX

2009-11-03

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for providing acidic gas to a subsurface formation is described herein. The method may include providing heat from one or more heaters to a portion of a subsurface formation; producing fluids that include one or more acidic gases from the formation using a heat treatment process. At least a portion of one of the acidic gases may be introduced into the formation, or into another formation, through one or more wellbores at a pressure below a lithostatic pressure of the formation in which the acidic gas is introduced.

Hydrogeologic framework of the Floridan aquifer system in Florida and in parts of Georgia, South Carolina, and Alabama

USGS Publications Warehouse

Miller, James A.

1986-01-01

The Floridan aquifer system of the Southeastern United States is comprised of a thick sequence of carbonate rocks that are mostly of Paleocene to early Miocene age and that are hydraulically connected in varying degrees. The aquifer system consists of a single vertically continuous permeable unit updip and of two major permeable zones (the Upper and Lower Floridan aquifers) separated by one of seven middle confining units downdip. Neither the boundaries of the aquifer system or of its component high- and low-permeability zones necessarily conform to either formation boundaries or time-stratigraphic breaks. The rocks that make up the Floridan aquifer system, its upper and lower confining units, and a surficial aquifer have been separated into several chronostratigraphic units. The external and internal geometry of these stratigraphic units is presented on a series of structure contour and isopach maps and by a series of geohydrologic cross sections and a fence diagram. Paleocene through middle Eocene units consist of an updip clastic facies and a downdip carbonate bank facies, that extends progressively farther north and east in progressively younger units. Upper Eocene and Oligocene strata are predominantly carbonate rocks throughout the study area. Miocene and younger strata are mostly clastic rocks. Subsurface data show that some modifications in current stratigraphic nomenclature are necessary. First, the middle Eocene Lake City Limestone cannot be distinguished lithologically or faunally from the overlying middle Eocene Avon Park 'Limestone.' Accordingly, it is proposed that the term Lake City be abandoned and the term Avon Park Formation be applied to the entire middle Eocene carbonate section of peninsular Florida and southeastern Georgia. A reference well section in Levy County, Fla., is proposed for the expanded Avon Park Formation. The Avon Park is called a 'formation' more properly than a 'limestone' because the unit contains rock types other than limestone. Second, like the Avon Park, the lower Eocene Oldsmar and Paleocene Cedar Keys 'Limestones' of peninsular Florida practically everywhere contain rock types other than limestone. It is therefore proposed that these units be referred to more accurately as Oldsmar Formation and Cedar Keys Formation. The uppermost hydrologic unit in the study area is a surficial aquifer that can be divided into (1) a fluvial sand-and-gravel aquifer in southwestern Alabama and westernmost panhandle Florida, (2) limestone and sandy limestone of the Biscayne aquifer in southeastern peninsular Florida, and (3) a thin blanket of terrace and fluvial sands elsewhere. The surficial aquifer is underlain by a thick sequence of fine clastic rocks and low-permeability carbonate rocks, most of which are part of the middle Miocene Hawthorn Formation and all of which form the upper confining unit of the Floridan aquifer system. In places, the upper confining unit has been removed by erosion or is breached by sinkholes. Water in the Floridan aquifer system thus occurs under unconfined, semiconfined, or fully confined conditions, depending upon the presence, thickness, and integrity of the upper confining unit. Within the Floridan aquifer system, seven low permeability zones of subregional extent split the aquifer system in most places into an Upper and Lower Floridan aquifer. The Upper Floridan aquifer, which consists of all or parts of rocks of Oligocene age, late Eocene age, and the upper half of rocks of middle Eocene age, is highly permeable. The middle confining units that underlie the Upper Floridan are mostly of middle Eocene age but may be as young as Oligocene or as old as early Eocene. Where no middle confining unit exists, the entire aquifer system is comprised of permeable rocks and for hydrologic discussions is treated as the Upper Floridan aquifer. The Lower Floridan aquifer contains a cavernous high-permeability horizon in the lower part of the early Eocene of south

Comprehensive gravitational modeling of the vertical cylindrical prism by Gauss-Legendre quadrature integration

NASA Astrophysics Data System (ADS)

Asgharzadeh, M. F.; Hashemi, H.; von Frese, R. RB

2018-01-01

Forward modeling is the basis of gravitational anomaly inversion that is widely applied to map subsurface mass variations. This study uses numerical least-squares Gauss-Legendre quadrature (GLQ) integration to evaluate the gravitational potential, anomaly and gradient components of the vertical cylindrical prism element. These results, in turn, may be integrated to accurately model the complete gravitational effects of fluid bearing rock formations and other vertical cylinder-like geological bodies with arbitrary variations in shape and density. Comparing the GLQ gravitational effects of uniform density, vertical circular cylinders against the effects calculated by a number of other methods illustrates the veracity of the GLQ modeling method and the accuracy limitations of the other methods. Geological examples include modeling the gravitational effects of a formation washout to help map azimuthal variations of the formation's bulk densities around the borehole wall. As another application, the gravitational effects of a seismically and gravimetrically imaged salt dome within the Laurentian Basin are evaluated for the velocity, density and geometric properties of the Basin's sedimentary formations.

Linking Surface and Subsurface Processes: Implications for Seismic Hazards in Southern California

NASA Astrophysics Data System (ADS)

Lin, J. C.; Moon, S.; Yong, A.; Meng, L.; Martin, A. J.; Davis, P. M.

2017-12-01

Earth's surface and subsurface processes such as bedrock weathering, soil production, and river incision can influence and be influenced by spatial variations in the mechanical strength of surface material. Mechanically weakened rocks tend to have reduced seismic velocity, which can result in larger ground-motion amplification and greater potential for earthquake-induced damages. However, the influence and extent of surface and subsurface processes on the mechanical strength of surface material and seismic site conditions in southern California remain unclear. In this study, we examine whether physics-based models of surface and subsurface processes can explain the spatial variability and non-linearity of near-surface seismic velocity in southern California. We use geophysical measurements (Yong et al., 2013; Ancheta et al., 2014), consisting of shear-wave velocity (Vs) tomography data, Vs profiles, and the time-averaged Vs in the upper 30 m of the crust (Vs30) to infer lateral and vertical variations of surface material properties. Then, we compare Vs30 values with geologic and topographic attributes such as rock type, slope, elevation, and local relief, as well as metrics for surface processes such as soil production and bedrock weathering from topographic stress, frost cracking, chemical reactions, and vegetation presence. Results from this study will improve our understanding of physical processes that control subsurface material properties and their influences on local variability in seismic site conditions.

Seismological evidence for monsoon induced micro to moderate earthquake sequence beneath the 2011 Talala, Saurashtra earthquake, Gujarat, India

NASA Astrophysics Data System (ADS)

Singh, A. P.; Mishra, O. P.

2015-10-01

In order to understand the processes involved in the genesis of monsoon induced micro to moderate earthquakes after heavy rainfall during the Indian summer monsoon period beneath the 2011 Talala, Saurashtra earthquake (Mw 5.1) source zone, we assimilated 3-D microstructures of the sub-surface rock materials using a data set recorded by the Seismic Network of Gujarat (SeisNetG), India. Crack attributes in terms of crack density (ε), the saturation rate (ξ) and porosity parameter (ψ) were determined from the estimated 3-D sub-surface velocities (Vp, Vs) and Poisson's ratio (σ) structures of the area at varying depths. We distinctly imaged high-ε, high-ξ and low-ψ anomalies at shallow depths, extending up to 9-15 km. We infer that the existence of sub-surface fractured rock matrix connected to the surface from the source zone may have contributed to the changes in differential strain deep down to the crust due to the infiltration of rainwater, which in turn induced micro to moderate earthquake sequence beneath Talala source zone. Infiltration of rainwater during the Indian summer monsoon might have hastened the failure of the rock by perturbing the crustal volume strain of the causative source rock matrix associated with the changes in the seismic moment release beneath the surface. Analyses of crack attributes suggest that the fractured volume of the rock matrix with high porosity and lowered seismic strength beneath the source zone might have considerable influence on the style of fault displacements due to seismo-hydraulic fluid flows. Localized zone of micro-cracks diagnosed within the causative rock matrix connected to the water table and their association with shallow crustal faults might have acted as a conduit for infiltrating the precipitation down to the shallow crustal layers following the fault suction mechanism of pore pressure diffusion, triggering the monsoon induced earthquake sequence beneath the source zone.

Imaging near-subsurface subrosion structures and faults using SH-wave reflection seismics

NASA Astrophysics Data System (ADS)

Wadas, Sonja; Polom, Ulrich; Buness, Hermann; Krawczyk, Charlotte

2016-04-01

Subrosion is a term for underground leaching of soluble rocks and is a global phenomenon. It involves dissolution of evaporites due to the presence of unsaturated water, fractures and faults. Fractures and faults are pathways for water to circulate and to generate subsurface cavities. Depending on the leached material and the parameters of the generation process, especially the dissolution rate, different kinds of subrosion structures evolve in the subsurface. The two end members are collapse and depression structures. Subrosion is a natural process, but it can be enhanced by anthropogenic factors like manipulation of the aquifer system and groundwater flow and by e.g. extraction of saline water. The formation of sinkholes and depressions are a dangerous geohazard, especially if they occur in urban areas, which often leads to building and infrastructural damage and life-threatening situations. For this reason investigations of the processes that induce subrosion and a detailed analysis of the resulting structures are of importance. To develop a comprehensive model of near-subsurface subrosion structures, reflection seismics is one of the methods used by the Leibniz Institute for Applied Geophysics. The study area is located in the city of Bad Frankenhausen in northern Thuringia, Germany. Most of the geological underground of Thuringia is characterized by Permian deposits. Bad Frankenhausen is situated directly south of the Kyffhäuser mountain range at the Kyffhäuser Southern Margin Fault. This major fault is one of the main pathways for the circulating ground- and meteoric waters that leach the Permian deposits, especially the Leine-, Staßfurt- and Werra Formations. 2014 and 2015 eight shear wave reflection seismic profiles were carried out in the urban area of Bad Frankenhausen and three profiles in the countrified surroundings. Altogether ca. 3.6 km were surveyed using a landstreamer as receiver and an electro-dynamic vibrator as source. The surveys were adjusted in able to measure in the medieval center of Bad Frankenhausen. This required special equipment and configuration due to the densely built-up area, the differing ground conditions and the varying topography. The analysis of the seismic sections revealed structures associated with the continuing subrosion of the Permian deposits. The reflection patterns indicate heterogeneous near-surface geology of lateral and vertical variations in forms of discontinuous reflectors, small-scale fractures and faults. The fractures and faults also serve as additional pathways for the circulating water and the deposits are subsiding along these features, resulting in the formation of depression structures in the near-subsurface. Diffractions in the unmigrated sections indicate voids in the subsurface that develop due to the longtime subrosion processes. Besides these structures, variations of the traveltime, absorption and scattering of the seismic waves induced by the subrosion processes are visible.

Subsurface and petroleum geology of the southwestern Santa Clara Valley ("Silicon Valley"), California

USGS Publications Warehouse

Stanley, Richard G.; Jachens, Robert C.; Lillis, Paul G.; McLaughlin, Robert J.; Kvenvolden, Keith A.; Hostettler, Frances D.; McDougall, Kristin A.; Magoon, Leslie B.

2002-01-01

Gravity anomalies, historical records of exploratory oil wells and oil seeps, new organic-geochemical results, and new stratigraphic and structural data indicate the presence of a concealed, oil-bearing sedimentary basin beneath a highly urbanized part of the Santa Clara Valley, Calif. A conspicuous isostatic-gravity low that extends about 35 km from Palo Alto southeastward to near Los Gatos reflects an asymmetric, northwest-trending sedimentary basin comprising low-density strata, principally of Miocene age, that rest on higher-density rocks of Mesozoic and Paleogene(?) age. Both gravity and well data show that the low-density rocks thin gradually to the northeast over a distance of about 10 km. The thickest (approx 4 km thick) accumulation of low-density material occurs along the basin's steep southwestern margin, which may be controlled by buried, northeast-dipping normal faults that were active during the Miocene. Movement along these hypothetical normal faults may been contemporaneous (approx 17–14 Ma) with sedimentation and local dacitic and basaltic volcanism, possibly in response to crustal extension related to passage of the northwestward-migrating Mendocino triple junction. During the Pliocene and Quaternary, the normal faults and Miocene strata were overridden by Mesozoic rocks, including the Franciscan Complex, along northeastward-vergent reverse and thrust faults of the Berrocal, Shannon, and Monte Vista Fault zones. Movement along these fault zones was accompanied by folding and tilting of strata as young as Quaternary and by uplift of the modern Santa Cruz Mountains; the fault zones remain seismically active. We attribute the Pliocene and Quaternary reverse and thrust faulting, folding, and uplift to compression caused by local San Andreas Fault tectonics and regional transpression along the Pacific-North American Plate boundary. Near the southwestern margin of the Santa Clara Valley, as many as 20 exploratory oil wells were drilled between 1891 and 1929 to total depths as great as 840 m. At least one pump unit is still standing. Although no lithologic or paleontologic samples are available from the wells, driller's logs indicate the presence of thick intervals of brown shale and sandstone resembling nearby outcrops of the Miocene Monterey Formation. Small amounts of oil and gas were observed in several wells, but commercial production was never established. Oil from the Peck well in Los Gatos is highly biodegraded, contains biomarkers commonly found in oils derived from the Monterey Formation, and has a stable-C-isotopic (d13C) composition of –23.32 permil, indicating derivation from a Miocene Monterey Formation source rock. Preliminary calculations suggest that about 1 billion barrels of oil may have been generated from source rocks within the Monterey Formation in the deepest part of the subsurface sedimentary basin between Los Gatos and Cupertino. Most of this oil was probably lost to biodegradation, oxidation, and leakage to the surface, but some oil may have accumulated in as-yet-undiscovered structural and stratigraphic traps along the complex structural boundary between the Santa Clara Valley and the Santa Cruz Mountains. Although some of these undiscovered accumulations of oil may be of commercial size, future petroleum exploration is unlikely because most of the area is currently devoted to residential, recreational, commercial, and industrial uses.

Novel determination of radon-222 velocity in deep subsurface rocks and the feasibility to using radon as an earthquake precursor

NASA Astrophysics Data System (ADS)

Zafrir, Hovav; Ben Horin, Yochai; Malik, Uri; Chemo, Chaim; Zalevsky, Zeev

2016-09-01

A novel technique utilizing simultaneous radon monitoring by gamma and alpha detectors to differentiate between the radon climatic driving forces and others has been improved and used for deep subsurface investigation. Detailed long-term monitoring served as a proxy for studying radon movement within the shallow and deep subsurface, as well as for analyzing the effect of various parameters of the radon transport pattern. The main achievements of the investigation are (a) determination, for the first time, of the radon movement velocity within rock layers at depths of several tens of meters, namely, 25 m/h on average; (b) distinguishing between the diurnal periodical effect of the ambient temperature and the semidiurnal effect of the ambient pressure on the radon temporal spectrum; and (c) identification of a radon random preseismic anomaly preceding the Nuweiba, M 5.5 earthquake of 27 June 2015 that occurred within Dead Sea Fault Zone.

Origin Of Black Shale (Marl) Formation Aided By Continuous Volcanism For 10Ma Including Oceanic Anoxic Event, OAE2 (93-93.5 Ma) In The Eagle Ford Formation In South Texas

NASA Astrophysics Data System (ADS)

Chakrabarty, P.; Basu, A. R.

2017-12-01

We report LA-ICPMS U-Pb ages and Hf isotopes of zircons, petrography, major and trace elements and X-ray diffraction (XRD) analyses of whole rock black shales(marls) from volcanic subsurface as well as surface exposure ash beds of the Eagle Ford and Boquillas Formations in South Texas. Zircons from the middle part of the 300ft long Eagle Ford cores yield ages of 93.2±1.66 Ma, 94.13±1.25 Ma and 93.7±1.9 Ma. These ages are consistent with the Cenomanian-Turonian (C-T) age of deposition in three contiguous cores with spatial separation of 140 miles. An approximate 10Ma duration of deposition of volcanic ash and marl, at a rate of 28ft/Ma for the Eagle Ford is suggested from the 85.76 to 95.5 Ma ages. These ages are from the Eagle Ford ash beds, below the Austin Chalk and above the Buda Limestone and cover the Oceanic Anoxic Event 2 at the C-T boundary. Zircons from 7 ash beds in the surface exposures of the Boquillas Formation near Del Rio, yield ages between 84.63 Ma - 90.91 Ma, implying younger than C-T boundary ages for these samples. The mineralogy, major and trace elements of the ash beds suggest their source from nearby arc-derived calc-alkaline volcanism. The ɛHf(T) of the analyzed ash bed zircons yield values between 0 - +8 averaging at +3.5, clearly indicating a mantle component in the host magmas of the zircons. This initial range of ɛHf(T) is similar to arc-volcanism signatures such as the Quaternary andesitic volcanism in Central Mexico. Petrographic analyses of marls away from the visible tuff layer contain phenocrysts of biotite, alkali feldspar and andesitic rock fragments. The whole rock marl with high concentration of some transition metals (V, Zn, Ni, Pb, Mo) and relatively higher MgO and TiO2 contents indicate contemporaneous arc volcanic activity at the time of marl deposition. XRD of subsurface Eagle Ford bulk marl samples from different depths in 4 cores, show volcanogenic clays, such as montmorillonite, vermiculite, dickite and halloysite 10Å, ranging from 2 to 12% in modal abundance. This observation indicates continuous volcanism throughout the Eagle Ford deposition. This volcanism during the Eagle Ford deposition of volcanic silicic sediments and carbonates was part of the global continental arc flare-ups in the Cretaceous, responsible for greenhouse conditions and subsequent anoxia during marl deposition.

Provenance and paleogeography of the Devonian Durazno Group, southern Parana Basin in Uruguay

NASA Astrophysics Data System (ADS)

Uriz, N. J.; Cingolani, C. A.; Basei, M. A. S.; Blanco, G.; Abre, P.; Portillo, N. S.; Siccardi, A.

2016-03-01

A succession of Devonian cover rocks occurs in outcrop and in the subsurface of central-northern Uruguay where they were deposited in an intracratonic basin. This Durazno Group comprises three distinct stratigraphic units, namely the Cerrezuelo, Cordobés and La Paloma formations. The Durazno Group does not exceed 300 m of average thickness and preserves a transgressive-regressive cycle within a shallow-marine siliciclastic shelf platform, and is characterized by an assemblage of invertebrate fossils of Malvinokaffric affinity especially within the Lower Devonian Cordobés shales. The sedimentary provenance of the Durazno Group was determined using petrography, geochemistry, and morphological studies of detrital zircons as well as their U-Pb ages. Sandstone petrography of Cerrezuelo and La Paloma sequences shows that they have a dominantly quartz-feldspathic composition with a minor contribution of other minerals. Whole-rock geochemical data indicate that alteration was strong in each of the three formations studied; chondritic-normalized REE patterns essentially parallel to PAAS, the presence of a negative Eu-anomaly, and Th/Sc and La/Hf ratios point to an average source composition similar to UCC or slightly more felsic. Within the Cerrezuelo Formation, recycling of older volcano-metasedimentary sources is interpreted from Zr/Sc ratios and high Hf, Zr, and REE concentrations. U-Pb detrital zircon age populations of the Cerrezuelo and La Paloma formations indicate that the principal source terranes are of Neoproterozoic age, but include also minor populations derived from Mesoproterozoic and Archean-Paleoproterozoic rocks. A provenance from the Cuchilla Dionisio-Dom Feliciano, Nico Pérez and Piedra Alta terranes of Uruguay and southern Brazil is likely. This study establishes an intracratonic extensional tectonic setting during Durazno time. Considering provenance age sources, regional paleocurrent distributions and the established orogenic history recorded in SW Gondwana, we suggest that the basin fill was derived from paleohighs located in what is currently SE Uruguay.

Karst connections between unconfined aquifers and the Upper Floridan aquifer in south Georgia: geophysical evidence and hydrogeological models

NASA Astrophysics Data System (ADS)

Thieme, D. M.; Denizman, C.

2011-12-01

Buried karst features in sedimentary rocks of the south Georgia Coastal Plain present a challenge for hydrogeological models of recharge and confined flow within the underlying Upper Floridan aquifer. The Withlacoochee River, the trunk stream for the area, frequently disappears into subsurface caverns as it makes its way south to join the Suwannee River in northern Florida. The Withlacoochee also receives inputs from small ponds and bays which in turn receive spring and seep groundwater inputs. We have mapped karst topography at the "top of rock" using ground-penetrating radar (GPR). Up to seven meters of relief is indicated for the paleotopography on Miocene to Pliocene rocks, contrasting with the more subdued relief of the modern landscape. Current stratigraphic and hydrogeological reconstructions do not incorporate this amount of relief or lateral variation in the confining beds. One "pipe" which is approximately four meters in diameter is being mapped in detail. We have field evidence at this location for rapid movement of surficial pond and river water with a meteoric signature through several separate strata of sedimentary rock into an aquifer in the Hawthorn formation. We use our geophysical and hydrological field evidence to constrain quantitative hydrogeological models for the flow rates into and out of both this upper aquifer and the underlying Upper Floridan aquifer, which is generally considered to be confined by the clays of the Hawthorn.

Can a fractured caprock self-heal?

NASA Astrophysics Data System (ADS)

Elkhoury, Jean E.; Detwiler, Russell L.; Ameli, Pasha

2015-05-01

The ability of geologic seals to prevent leakage of fluids injected into the deep subsurface is critical for mitigating risks associated with greenhouse-gas sequestration and natural-gas production. Fractures caused by tectonic or injection-induced stresses create potential leakage pathways that may be further enhanced by mineral dissolution. We present results from reactive-flow experiments in fractured caprock (dolomitic anhydrite), where additional dissolution occurs in the rock matrix adjacent to the fracture surfaces. Preferential dissolution of anhydrite left a compacted layer of dolomite in the fractures. At lower flow rate, rock-fluid reactions proceeded to near equilibrium within the fracture with preferential flow paths persisting over the 6-month duration of the experiment and a negligible change in permeability. At higher flow rate, permeability decreased by a dramatic two orders of magnitude. This laboratory-scale observation of self-healing argues against the likelihood of runaway permeability growth in fractured porous caprock composed of minerals with different solubilities and reaction kinetics. However, scaling arguments suggest that at larger length scales this self-healing process may be offset by the formation of dissolution channels. Our results have relevance beyond the greenhouse-gas sequestration problem. Chemical disequilibrium at waste injection sites and in hydrothermal reservoirs will lead to reactive flows that may also significantly alter formation permeability.

National Uranium Resource Evaluation: Marfa Quadrangle, Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henry, C D; Duex, T W; Wilbert, W P

1982-09-01

The uranium favorability of the Marfa 1/sup 0/ by 2/sup 0/ Quadrangle, Texas, was evaluated in accordance with criteria established for the National Uranium Resource Evaluation. Surface and subsurface studies, to a 1500 m (5000 ft) depth, and chemical, petrologic, hydrogeochemical, and airborne radiometric data were employed. The entire quadrangle is in the Basin and Range Province and is characterized by Tertiary silicic volcanic rocks overlying mainly Cretaceous carbonate rocks and sandstones. Strand-plain sandstones of the Upper Cretaceous San Carlos Formation and El Picacho Formation possess many favorable characteristics and are tentatively judged as favorable for sandstone-type deposits. The Tertiarymore » Buckshot Ignimbrite contains uranium mineralization at the Mammoth Mine. This deposit may be an example of the hydroauthigenic class; alternatively, it may have formed by reduction of uranium-bearing ground water produced during diagenesis of tuffaceous sediments of the Vieja Group. Although the presence of the deposit indicates favorability, the uncertainty in the process that formed the mineralization makes delineation of a favorable environment or area difficult. The Allen intrusions are favorable for authigenic deposits. Basin fill in several bolsons possesses characteristics that suggest favorability but which are classified as unevaluated because of insufficient data. All Precambrian, Paleozoic, other Mesozoic, and other Cenozoic environments are unfavorable.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutierrez, Marte

Colorado School of Mines conducted research and training in the development and validation of an advanced CO{sub 2} GS (Geological Sequestration) probabilistic simulation and risk assessment model. CO{sub 2} GS simulation and risk assessment is used to develop advanced numerical simulation models of the subsurface to forecast CO2 behavior and transport; optimize site operational practices; ensure site safety; and refine site monitoring, verification, and accounting efforts. As simulation models are refined with new data, the uncertainty surrounding the identified risks decrease, thereby providing more accurate risk assessment. The models considered the full coupling of multiple physical processes (geomechanical and fluidmore » flow) and describe the effects of stochastic hydro-mechanical (H-M) parameters on the modeling of CO{sub 2} flow and transport in fractured porous rocks. Graduate students were involved in the development and validation of the model that can be used to predict the fate, movement, and storage of CO{sub 2} in subsurface formations, and to evaluate the risk of potential leakage to the atmosphere and underground aquifers. The main major contributions from the project include the development of: 1) an improved procedure to rigorously couple the simulations of hydro-thermomechanical (H-M) processes involved in CO{sub 2} GS; 2) models for the hydro-mechanical behavior of fractured porous rocks with random fracture patterns; and 3) probabilistic methods to account for the effects of stochastic fluid flow and geomechanical properties on flow, transport, storage and leakage associated with CO{sub 2} GS. The research project provided the means to educate and train graduate students in the science and technology of CO{sub 2} GS, with a focus on geologic storage. Specifically, the training included the investigation of an advanced CO{sub 2} GS simulation and risk assessment model that can be used to predict the fate, movement, and storage of CO{sub 2} in underground formations, and the evaluation of the risk of potential CO{sub 2} leakage to the atmosphere and underground aquifers.« less

Monitoring and Quantifying Subsurface Ice and Water Content in Permafrost Regions Based on Geophysical Data Sets

NASA Astrophysics Data System (ADS)

Hauck, C.; Bach, M.; Hilbich, C.

2007-12-01

Based on recent observational evidence of climate change in permafrost regions, it is now recognised that a detailed knowledge of the material composition of the subsurface in permafrost regions is required for modelling of the future evolution of the ground thermal regime and an assessment of the hazard potential due to degrading permafrost. However, due to the remote location of permafrost areas and the corresponding difficulties in obtaining high-quality data sets of the subsurface, knowledge about the material composition in permafrost areas is scarce. In frozen ground subsurface material may consist of four different phases: rock/soil matrix, unfrozen pore water, ice and air-filled pore space. Applications of geophysical techniques for determining the subsurface composition are comparatively cheap and logistically feasible alternatives to the single point information from boreholes. Due to the complexity of the subsurface a combination of complementary geophysical methods (e.g. electrical resistivity tomography (ERT) and refraction seismic tomography) is often favoured to avoid ambiguities in the interpretation of the results. The indirect nature of geophysical soundings requires a relation between the measured variable (electrical resistivity, seismic velocity) and the rock-, water-, ice- and air content. In this contribution we will present a model which determines the volumetric fractions of these four phases from tomographic electrical and seismic data sets. The so-called 4-phase model is based on two well-known geophysical mixing rules using observed resistivity and velocity data as input data on a 2-dimensional grid. Material properties such as resistivity and P- wave velocity of the host rock material and the pore water have to be known beforehand. The remaining free model parameters can be determined by a Monte-Carlo approach, the results of which are used additionally as indicator for the reliability of the model results. First results confirm the good model performance for various field cases in permafrost research. Especially the 2- dimensional monitoring and detection of ground ice and air cavities in the blocky surface layer was substantially improved. Validation of the model results was obtained using borehole and energy balance data from different permafrost sites.

Groundwater geochemistry of the Yucatan Peninsula, Mexico: Constraints on stratigraphy and hydrogeology

NASA Astrophysics Data System (ADS)

Perry, Eugene; Paytan, Adina; Pedersen, Bianca; Velazquez-Oliman, Guadalupe

2009-03-01

SummaryWe report 87Sr/ 86Sr and ion concentrations of sulfate, chloride, and strontium in the groundwater of the northern and central Yucatan Peninsula, Mexico. Correlation between these data indicates that ejecta from the 65.95 m.y. old Chicxulub impact crater have an important effect on hydrogeology, geomorphology, and soil development of the region. Ejecta are present at relatively shallow subsurface depths in north-central Yucatan and at the surface along the Rio Hondo escarpment in southeast Quintana Roo, where they are referred to as the Albion Formation. Anhydrite/gypsum (and by inference celestite) are common in impact ejecta clasts and in beds and cements of overlying Paleocene and Lower Eocene rocks cored around the margin of the crater. The sulfate-rich minerals that are found in rocks immediately overlying the impact ejecta blanket, may either be partially mobilized from the ejecta layer itself or may have been deposited after the K/T impact event in an extensive pre-Oligocene shallow sea. These deposits form a distinctive sedimentary package that can be easily traced by the Eocene-Cretaceous 87Sr/ 86Sr signal. A distinct Sr isotopic signature and high SO 4/Cl ratios are observed in groundwater of northwestern and north-central Yucatan that interacts with these rocks. Moreover, the distribution of the gypsum-rich stratigraphic unit provides a solution-enhanced subsurface drainage pathway for a broad region characterized by dissolution features (poljes) extending from Chetumal, Quintana Roo to Campeche, Campeche. The presence of gypsum quarries in the area is also consistent with a sulfate-rich stratigraphic "package" that includes ejecta. The distinctive chemistry of groundwater that has been in contact with evaporite/ejecta can be used to trace flow directions and confirms a groundwater divide in the northern Peninsula. Information about groundwater flow directions and about deep subsurface zones of high permeability is useful for groundwater and liquid waste management in the area. Where it discharges at the coast, the unique chemistry of the groundwater that has interacted with the evaporite/ejecta strata may also have significant geomorphologic implications. While groundwater-seawater mixing at the coast has been shown to dissolve and erode limestone, PHREEQC modeling shows that mixing of water nearly saturated in CaSO 4 with seawater has a less vigorous dissolution effect due to its high Ca content.

A High-Resolution Multitechniques Approach to Characterize Bio-Organo-Mineral Associations Within Rock Samples: Tracking Biological vs Abiotic Processes? Towards a Better Understanding of the Deep Carbon Cycle.

NASA Astrophysics Data System (ADS)

Pisapia, C.

2015-12-01

Among all elements, carbon plays one of the major roles for the sustainability of life on Earth. Past considerations of the carbon cycle have mainly focused on surface processes occurring at the atmosphere, oceans and shallow crustal environments. By contrast, little is known about the Deep Carbon cycle whereas both geochemical and biological processes may induce organic carbon production and/or consumption at depth. Indeed, the nowadays-recognized capability of geochemical processes such as serpentinization to generate abiotic organic compounds as well as the existence of a potentially important intraterrestrial life raises questions about the limit of biotic/abiotic carbon on Earth's deep interior and how it impacts global biogeochemical cycles. It is then mandatory to increase our knowledge on the nature and extent of carbon reservoirs along with their sources, sinks and fluxes in the subsurface. This implies to be able to finely characterize organomineral associations within crustal rocks although it might be hampered by the scarceness and heterogeneous micrometric spatial distribution of organic molecules in natural rocks. We then developed an in situ analytical strategy based on the combination of high-resolution techniques to track organic molecules at the pore level in natural rocks and to determine their biological or abiotic origin. We associated classical high-resolution techniques and synchrotron-based imaging techniques in order to characterize their nature and localization (SEM/TEM, coupled CLSM/Raman spectroscopy, Tof-SIMS) along with their 3D-distribution relatively to mineral phases (S-FTIR, S-DeepUV, XANES, Biphoton microscopy). The effectiveness of this approach to shed light on the speciation and nature of carbon in subsurface environments will be illustrated through the study of (i) subsurface ecosystems and abiotic organic carbon within ultramafic rocks of the oceanic lithosphere as putative analogs for the nature and functioning of primitive ecosystems on Earth and of (ii) ecosystems inhabiting Archean craton and potentially playing a role in punk-rock karstification processes and rocks weathering.

Geophysical Characterization of Serpentinite Hosted Hydrogeology at the McLaughlin Natural Reserve, Coast Range Ophiolite

NASA Astrophysics Data System (ADS)

Ortiz, Estefania; Tominaga, Masako; Cardace, Dawn; Schrenk, Matthew O.; Hoehler, Tori M.; Kubo, Michael D.; Rucker, Dale F.

2018-01-01

Geophysical remote sensing both on land and at sea has emerged as a powerful approach to characterize in situ water-rock interaction processes in time and space. We conducted 2-D Electrical Resistivity Tomography (ERT) surveys to investigate in situ hydrogeological architecture within the Jurassic age tectonic mélange portion of the Coast Range Ophiolite Microbial Observatory (CROMO) during wet and dry seasons, where water-rock interactive processes are thought to facilitate a subsurface biosphere. Integrating survey tracks traversing two previously drilled wells, QV1,1 and CSW1,1 at the CROMO site with wireline and core data, and the Serpentine Valley site, we successfully documented changes in hydrogeologic properties in the CROMO formation, i.e., lateral and vertical distribution of conductive zones and their temporal behavior that are dependent upon seasonal hydrology. Based on the core-log-ERT integration, we propose a hydrogeological architectural model, in which the formation is composed of three distinct aquifer systems: perched serpentinite aquifer without seasonal dependency (shallow system), well-cemented serpentine confining beds with seasonal dependency (intermediate system), serpentinite aquifer (deep system), and the ultramafic basement that acts as a quasi-aquiclude (below the deep system). The stunning contrast between the seasonality in the surface water availability and groundwater storativity in the formation allowed us to locate zones where serpentinite weathering and possibly deeper serpentinization processes might have taken place. We based our findings primarily on lithological composition and the distribution of the conductive formation, our work highlights the link between serpentinite weathering processes and possible sources of water in time and space.

30 CFR 250.801 - Subsurface safety devices.

Code of Federal Regulations, 2012 CFR

2012-07-01

... permafrost, unstable bottom conditions, hydrate formation, or paraffins, an alternate setting depth of the... such as permafrost, unstable bottom conditions, hydrate formations, and paraffins. (g) Subsurface...

30 CFR 250.801 - Subsurface safety devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... permafrost, unstable bottom conditions, hydrate formation, or paraffins, an alternate setting depth of the... such as permafrost, unstable bottom conditions, hydrate formations, and paraffins. (g) Subsurface...

30 CFR 250.801 - Subsurface safety devices.

Code of Federal Regulations, 2014 CFR

2014-07-01

... permafrost, unstable bottom conditions, hydrate formation, or paraffins, an alternate setting depth of the... such as permafrost, unstable bottom conditions, hydrate formations, and paraffins. (g) Subsurface...

The Search for Sustainable Subsurface Habitats on Mars, and the Sampling of Impact Ejecta

NASA Astrophysics Data System (ADS)

Ivarsson, Magnus; Lindgren, Paula

2010-07-01

On Earth, the deep subsurface biosphere of both the oceanic and the continental crust is well known for surviving harsh conditions and environments characterized by high temperatures, high pressures, extreme pHs, and the absence of sunlight. The microorganisms of the terrestrial deep biosphere have an excellent capacity for adapting to changing geochemistry, as the alteration of the crust proceeds and the conditions of their habitats slowly change. Despite an almost complete isolation from surface conditions and the surface biosphere, the deep biosphere of the crustal rocks has endured over geologic time. This indicates that the deep biosphere is a self-sufficient system, independent of the global events that occur at the surface, such as impacts, glaciations, sea level fluctuations, and climate changes. With our sustainable terrestrial subsurface biosphere in mind, the subsurface on Mars has often been suggested as the most plausible place to search for fossil Martian life, or even present Martian life. Since the Martian surface is more or less sterile, subsurface settings are the only place on Mars where life could have been sustained over geologic time. To detect a deep biosphere in the Martian basement, drilling is a requirement. However, near future Mars sample return missions are limited by the mission's payload, which excludes heavy drilling equipment and restrict the missions to only dig the topmost meter of the Martian soil. Therefore, the sampling and analysis of Martian impact ejecta has been suggested as a way of accessing the deeper Martian subsurface without using heavy drilling equipment. Impact cratering is a natural geological process capable of excavating and exposing large amounts of rock material from great depths up to the surface. Several studies of terrestrial impact deposits show the preservation of pre-impact biosignatures, such as fossilized organisms and chemical biological markers. Therefore, if the Martian subsurface contains a record of life, it is reasonable to assume that biosignatures derived from the Martian subsurface could also be preserved in the Martian impact ejecta.

Potential effects of alpha-recoil on uranium-series dating of calcrete

USGS Publications Warehouse

Neymark, L.A.

2011-01-01

Evaluation of paleosol ages in the vicinity of Yucca Mountain, Nevada, at the time the site of a proposed high-level nuclear waste repository, is important for fault-displacement hazard assessment. Uranium-series isotope data were obtained for surface and subsurface calcrete samples from trenches and boreholes in Midway Valley, Nevada, adjacent to Yucca Mountain. 230Th/U ages of 33 surface samples range from 1.3 to 423 thousand years (ka) and the back-calculated 234U/238U initial activity ratios (AR) are relatively constant with a mean value of 1.54 ± 0.15 (1σ), which is consistent with the closed-system behavior. Subsurface calcrete samples are too old to be dated by the 230Th/U method. U-Pb data for post-pedogenic botryoidal opal from a subsurface calcrete sample show that these subsurface calcrete samples are older than ~ 1.65 million years (Ma), old enough to have attained secular equilibrium had their U-Th systems remained closed. However, subsurface calcrete samples show U-series disequilibrium indicating open-system behavior of 238U daughter isotopes, in contrast with the surface calcrete, where open-system behavior is not evident. Data for 21 subsurface calcrete samples yielded calculable 234U/238U model ages ranging from 130 to 1875 ka (assuming an initial AR of 1.54 ± 0.15, the mean value calculated for the surface calcrete samples). A simple model describing continuous α-recoil loss predicts that the 234U/238U and 230Th/238U ARs reach steady-state values ~ 2 Ma after calcrete formation. Potential effects of open-system behavior on 230Th/U ages and initial 234U/238U ARs for younger surface calcrete were estimated using data for old subsurface calcrete samples with the 234U loss and assuming that the total time of water-rock interaction is the only difference between these soils. The difference between the conventional closed-system and open-system ages may exceed errors of the calculated conventional ages for samples older than ~ 250 ka, but is negligible for younger soils.

Ancient Aqueous Conditions on Mars as Inferred from Spirit and Opportunity Rover Data

NASA Astrophysics Data System (ADS)

Arvidson, R. E.

2017-12-01

The Spirit and Opportunity rover missions have added significantly to our understanding of the availability of surface and subsurface waters on Mars over a range of timescales, from the Noachian Period until the present. The most important discoveries from Spirit's traverses and measurements are focused around Home Plate in the Noachian-aged Columbia Hills, Gusev Crater. Home Plate is postulated to be a largely eroded volcanoclastic construct. Spirit's wheels excavated a variety of hydrated sulfate minerals and iron oxides just beneath the surface in the vicinity of Home Plate, likely reworked hydrothermal deposits. Spirit also explored silica-rich deposits found adjacent to Home Plate of likely hydrothermal origin, perhaps deposited as sinters. Opportunity's exploration of the Burns formation sulfate-rich sandstones that underlie Meridiani Planum provided the key observations to infer an origin as sulfate-rich muds accumulating in shallow, ephemeral lakes during the late Noachian to early Hesperian Periods. Fluvial and aeolian activity reworked the muds into sandstones, to be later cemented and altered by rising groundwaters. Opportunity's exploration of the Noachian-aged 22 km diameter Endeavour Crater, combined with mineral mapping using Mars Reconnaissance Orbiter CRISM hyperspectral data, led to the discovery and characterization of ferric smectite-bearing layered outcrops and Al-rich smectites in fractures, both in the Matijevic formation that underlies Endeavour's ejecta (Shoemaker formation). In addition, Opportunity observations led to the discovery and characterization of: (a) extensive Ca sulfate veins in the above mentioned formations and in the overlying Grasberg formation, (b) Shoemaker formation rocks excavated from a soil-filled fracture coated by sulfates and Mn oxides, and (c) extensive Fe-Mg smectites in outcrops and strings of hematite-rich pebbles in sulfate-rich soil-filled fractures in Marathon Valley. Spirit and Opportunity observations thus add to the mounting evidence for significant subsurface aqueous alteration along fractures, in addition to the sustained presence of surface water during the Noachian to early Hesperian Eras.

Digitization of a geologic map for the Quebec-Maine-Gulf of Maine global geoscience transect

USGS Publications Warehouse

Wright, Bruce E.; Stewart, David B.

1990-01-01

The Bedrock Geologic Map of Maine was digitized and combined with digital geologic data for Quebec and the Gulf of Maine for the Quebec-Maine-Gulf of Maine Geologic Transect Project. This map is being combined with digital geophysical data to produce three-dimensional depictions of the subsurface geology and to produce cross sections of the Earth's crust. It is an essential component of a transect that stretches from the craton near Quebec City, Quebec, to the Atlantic Ocean Basin south of Georges Bank. The transect is part of the Global Geosciences Transect Project of the International Lithosphere Program. The Digital Line Graph format is used for storage of the digitized data. A coding scheme similar to that used for base category planimetric data was developed to assign numeric codes to the digitized geologic data. These codes were used to assign attributes to polygon and line features to describe rock type, age, name, tectonic setting of original deposition, mineralogy, and composition of igneous plutonic rocks, as well as faults and other linear features. The digital geologic data can be readily edited, rescaled, and reprojected. The attribute codes allow generalization and selective retrieval of the geologic features. The codes allow assignment of map colors based on age, lithology, or other attribute. The Digital Line Graph format is a general transfer format that is supported by many software vendors and is easily transferred between systems.

Basement structure based on gravity anomaly in the northern Noto peninsula, Central Japan

NASA Astrophysics Data System (ADS)

Mizubayashi, T.; Sawada, A.; Hamada, M.; Hiramatsu, Y.; Honda, R.

2012-12-01

Upper crustal block structures are usually defined by using surface information, such as geological and morphological data. The northern Noto Peninsula, central Japan, is divided into four geological block structures from tectonic geomorphologic perspectives (Ota and Hirakawa, 1979). This division is based on the surface crustal movement. To image the geological blocks three-dimensionally, it is necessary to construct a subsurface structure model. Gravity survey can clarify the detailed subsurface structure with dense gravity measurement. From the detailed Bouguer anomalies in the northwestern Noto Peninsula, Honda et al. (2008) suggested that the rupture size of the 2007 Noto Hanto earthquake was constrained by the geological block structures. Hiramatsu et al. (2008) also suggested the active faults on the seafloor, such as the source fault of the 2007 Noto Hanto earthquake plays a major role for the formation of the geological block structures. In this study, we analyze subsurface density structure based on the Bouguer anomaly and estimate the distribution of basement depth in the northern Noto Peninsula. We focus the relationship among the basement depth, the block structures and the active faults on the seafloor and discuss the block movement in the northern Noto Peninsula. We compiled the data measured and published previously (Gravity Database of Southwest Japan, 2001; Geological survey of Japan, 2004; Geographical survey institute of Japan, 2006; The Gravity Research Group in Southwest Japan, 2001; Komazawa and Okuma, 2010; Hokuriku electric power Co. Ltd., undisclosed) and calculated Bouguer anomaly in the northern Noto Peninsula. Based on this Bouguer anomaly, we analyzed subsurface density structures along 13 northeastern-southwestern profiles and 35 northwestern-southeastern profiles with the interval of 2 km using the two dimensional Talwani's method (Talwani et al., 1959). In the analysis, we assumed a density structure with four layers: basement (density is 2670kg/m3), Neocene volcanic rock (density is 2400kg/m3, or 2550kg/m3), Neocene sedimentary rock (density is 2200kg/m3), and Quaternary sedimentary rock (density is 1800kg/m3, or 1500kg/m3) (Honda et al., 2008). To compare our basement model to the geological block structures, we focus on a transition zone of the basement depth. We recognize that two of three geological block boundaries correspond to the transition zones. These boundaries also correspond to the boundary of active fault segments on the seafloor. Therefore, based on the relationship between the source fault of the 2007 Noto Hanto earthquake and the geological block, we suggest that the movement of those geological blocks is possibly controlled by the corresponding active fault segments. However, we find that the other block boundary doesn't correspond to the transition zone.

Sequence stratigraphy of the Monterey Formation, Santa Barbara County: Integration of physical, chemical, and biofacies data from outcrop and subsurface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bohacs, K.M.

1991-02-01

Deep basinal rocks of the Monterey Formation can be allocated to different depositional environments based on an integration of bedding, stacking patterns of facies, lithology, biofacies, and inorganic and organic chemistry. These rocks show evidence of systematic changes in depositional environments that can be related to eustatic sea level changes and basin evolution. Even deep-basinal environments are affected by changing sea level through changes in circulation patterns and intensities, nutrient budgets and dispersal patterns, and location and intensity of the oceanic oxygen minimum. The sequence-stratigraphic framework was constructed based on the physical expression of the outcrop strata and confirmed bymore » typing the outcrop sections to an integrated will-log/seismic grid through outcrop gamma-ray spectral profiles. Interpretation of a sequence boundary was based on increased proportions of hemipelagic facies and evidence of increased bottom-energy levels above the boundary, and local erosion and relief on the surface. The proportion of shallower water and reworked dinoflagellates increased to a local maximum above the boundary. Downlap surfaces exhibited increased proportions of pelagic facies around the surface, a secular change in the dominant lithology across the surface, evidence of decreased bottom-energy levels and terrigenous sedimentation rates, and little or not significant erosion on the surface. The proportion of deeper water dinoflagellates increased to a local maximum at or near the downlap surface; there was no evidence of reworked individuals. The detailed sequence-stratigraphic framework makes it possible to tie rock properties to genetic processes for construction of predictive models.« less

Mathematical Models of Seafloor Hydrothermal Systems Driven by Serpentinization of Peridotite

NASA Astrophysics Data System (ADS)

Lowell, R. P.; Rona, P. A.; Germanovich, L. N.

2001-12-01

Most seafloor hydrothermal systems are driven by heat transfer from subsurface magma bodies. At slow spreading ridges of the Atlantic and Indian oceans, however, magma supply is low; and tectonic activity brings mantle rocks to shallow depths in the crust. Then, the heat of formation released upon serpentinization of peridotite provides the energy source for hydrothermal circulation. This latter class of system has been relatively unstudied, but recent discoveries of peridotite-hosted hydrothermal systems along the Mid-Atlantic Ridge suggest that such systems may play an important role in geochemical cycling and biogeochemical processes. The likelihood that peridotite-hosted hydrothermal systems was more prevalent during the Archean further suggests that such systems may have played a role in the origin of life. We present the first mathematical models of seafloor hydrothermal systems driven by heat released upon serpentinization of peridotite. We assume seawater circulates through a major crack network in the host-peridotite and that cooling of the host-rock leads to the formation of microcracks through which the fluid infiltrates. Reaction of the fluid in microcracks with the host rock results in serpentinization and the heat released upon serpentinization is transported to the seafloor by the fluid circulating in the main crack network. The temperature and heat output of the resulting hydrothermal system is a function of the main network permeability and the rate at which the serpentinization reaction proceeds via diffusion and propagation of the microcracks. Although the temperature of such a system can be quite variable, vent temperatures between 10° C and 100° C are likely for typical crustal parameters.

Ocean Drilling Program Contributions to the Understanding of the Deep Subsurface Biosphere

NASA Astrophysics Data System (ADS)

Fisk, M. R.

2003-12-01

Tantalizing evidence for microbes in oceanic basalts has been reported for a few decades, but it was from rocks cored on Ocean Drilling Program (ODP) Leg 148 in 1993 that the first clear-cut evidence of microbial invasion of ocean basalts was obtained. (Work on ODP legs, starting with Leg 112 in 1986, had already revealed the presence of significant microbial biomass in sediments.) In 1997 ODP created the Deep Biosphere Program Planning Group to promote the investigation of the microbiology of the ocean crust. In 1999 ODP built a microbiology lab on the JOIDES Resolution, and used the lab that year (Legs 185 and 187) to test the amount of microbial contamination introduced into rocks during drilling and to establish cultures from cored basalts. These experiments have been repeated on several legs since then. The development of CORKs has permitted long-term sampling of subseafloor fluids, and microorganisms have been recovered from CORKed holes. Thus, ODP made it possible for the scientific community to address major questions about the biology of the igneous crust, such as, (1) What microbes are present? (2) How abundant are they? (3) How are they distributed? DNA from basalts and subseafloor fluids reveal what types of organisms are present. Cell abundance and biomass have been estimated based on cell counts and on organic content of basalts. Surveys of basalts in DSDP/ODP repositories indicate that microorganisms are ubiquitous in the igneous crust. Microorganisms are found in rocks that are close to 100° C. They are found as deep as 1500 m below the sea floor, and in rocks as young as a few years and as old as 170 million years. Because of the vast size of the habitat, microorganism, even if present in small numbers, could be a significant fraction of the Earth's biomass. In a short time ODP contributed to advances in our understanding of the oceanic subsurface biosphere. Answers to other significant questions such as: (1) How do the microorganisms live?, (2) What impact do subsurface microorganisms have on the surface biosphere? (3) And, what roles do the subsurface biosphere play in element cycling? will be answered by future drilling. The International Ocean Drilling Program (IODP) is in the enviable position of providing support to address these key questions about the Earth's subsurface biosphere.

Heating subsurface formations by oxidizing fuel on a fuel carrier

DOEpatents

Costello, Michael; Vinegar, Harold J.

2012-10-02

A method of heating a portion of a subsurface formation includes drawing fuel on a fuel carrier through an opening formed in the formation. Oxidant is supplied to the fuel at one or more locations in the opening. The fuel is combusted with the oxidant to provide heat to the formation.

A Microfluidics Study to Quantify the Impact of Microfracture Properties on Two-Phase Flow in Tight Rocks

NASA Astrophysics Data System (ADS)

Mehmani, A.; Kelly, S. A.; Torres-Verdin, C.; Balhoff, M.

2017-12-01

Microfluidics provides the opportunity for controlled experiments of immiscible fluid dynamics in quasi two-dimensional permeable media and allows their direct observation. We leverage microfluidics to investigate the impact of microfracture properties on water imbibition and drainage in a porous matrix. In the context of this work, microfractures are defined as apertures or preferential flow paths formed along planes of weakness, such as between two different rock fabrics. Patterns of pseudo-microfractures with orientations from parallel and perpendicular to fluid flow as well as variations in their connectivity were fabricated in glass micromodels; surface roughness of the micromodels was also varied utilizing a new method. Light microscopy and image analysis were used to quantify transient front advancement and trapped non-wetting phase saturation during imbibition as well as residual wetting phase saturation and its spatial distribution following drainage. Our experiments enable the assessment of quantitative relationships between fluid invasion rate and residual phase distributions as functions of microfracture network properties. Ultimately, the wide variety of microfluidic experiments performed in this study provide valuable insight into two-phase fluid dynamics in microfracture/matrix networks, the extent of fracture fluid invasion, and the saturation of trapped phases. In reservoir description, the geometries of subsurface fractures are often difficult to ascertain, but the distribution of rock types in a zone, from highly laminated to homogenous, can be reliably assessed with core data and well logs. Assuming that microcracks are functions of lamination planes (thin beds), then a priori predictions of the effect of microcracks on two-phase fluid flow across various geological conditions can possibly be upscaled via effective lamination properties. Such upscaling can significantly reduce the uncertainties associated with subsurface operations, including reservoir production, carbon storage and sequestration, and hazardous waste sequestration. A reliable prediction of capillary trapping, for instance, can determine the fracture fluid saturation subsequent to hydraulic fracturing of unconventional formations or the efficacy of water flooding in fractured reservoirs.

Brittle strength of basaltic rock masses with applications to Venus

NASA Astrophysics Data System (ADS)

Schultz, R. A.

1993-06-01

Spacecraft images of surfaces with known or suspected basaltic composition on Venus (as well as on moon and Mars) indicate that these rocks have been deformed in the brittle regime to form faults and perhaps joints, in addition to folding and more distributed types of deformation. This paper presents results of detailed examinations and interpretations of Venus surface materials which show that the strengths of basaltic rocks on planetary surfaces and in the shallow subsurface are significantly different from strength values commonly used in tectonic modeling studies which assume properties of either intact rock samples or single planar shear surface.

Investigation of the relationship between CO2 reservoir rock property change and the surface roughness change originating from the supercritical CO2-sandstone-groundwater geochemical reaction at CO2 sequestration condition

NASA Astrophysics Data System (ADS)

Lee, Minhee; Wang, Sookyun; Kim, Seyoon; Park, Jinyoung

2015-04-01

Lab scale experiments were performed to investigate the property changes of sandstone slabs and cores, resulting from the scCO2-rock-groundwater reaction for 180 days under CO2 sequestration conditions (100 bar and 50 °C). The geochemical reactions, including the surface roughness change of minerals in the slab, resulted from the dissolution and the secondary mineral precipitation for the sandstone reservoir of the Gyeongsang basin, Korea were reproduced in laboratory scale experiments and the relationship between the geochemical reaction and the physical rock property change was derived, for the consideration of successful subsurface CO2 sequestration. The use of the surface roughness value (SRrms) change rate and the physical property change rate to quantify scCO2-rock-groundwater reaction is the novel approach on the study area for CO2 sequestration in the subsurface. From the results of SPM (Scanning Probe Microscope) analyses, the SRrms for each sandstone slab was calculated at different reaction time. The average SRrms increased more than 3.5 times during early 90 days reaction and it continued to be steady after 90 days, suggesting that the surface weathering process of sandstone occurred in the early reaction time after CO2 injection into the subsurface reservoir. The average porosity of sandstone cores increased by 8.8 % and the average density decreased by 0.5 % during 90 days reaction and these values slightly changed after 90 days. The average P and S wave velocities of sandstone cores also decreased by 10 % during 90 days reaction. The trend of physical rock property change during the geochemical reaction showed in a logarithmic manner and it was also correlated to the logarithmic increase in SRrms, suggesting that the physical property change of reservoir rocks originated from scCO2 injection directly comes from the geochemical reaction process. Results suggested that the long-term estimation of the physical property change for reservoir rocks in CO2 injection site could be possible from the extrapolation process of SRrms and rocks property change rates, acquired from laboratory scale experiments. It will be aslo useful to determine the favorite CO2 injection site from the viewpoint of the safety.

The subsurface geology of Río Tinto: material examined during a simulated Mars drilling mission for the Mars Astrobiology Research and Technology Experiment (MARTE).

PubMed

Prieto-Ballesteros, Olga; Martínez-Frías, Jesús; Schutt, John; Sutter, Brad; Heldmann, Jennifer L; Bell, Mary Sue; Battler, Melissa; Cannon, Howard; Gómez-Elvira, Javier; Stoker, Carol R

2008-10-01

The 2005 Mars Astrobiology Research and Technology Experiment (MARTE) project conducted a simulated 1-month Mars drilling mission in the Río Tinto district, Spain. Dry robotic drilling, core sampling, and biological and geological analytical technologies were collectively tested for the first time for potential use on Mars. Drilling and subsurface sampling and analytical technologies are being explored for Mars because the subsurface is the most likely place to find life on Mars. The objectives of this work are to describe drilling, sampling, and analytical procedures; present the geological analysis of core and borehole material; and examine lessons learned from the drilling simulation. Drilling occurred at an undisclosed location, causing the science team to rely only on mission data for geological and biological interpretations. Core and borehole imaging was used for micromorphological analysis of rock, targeting rock for biological analysis, and making decisions regarding the next day's drilling operations. Drilling reached 606 cm depth into poorly consolidated gossan that allowed only 35% of core recovery and contributed to borehole wall failure during drilling. Core material containing any indication of biology was sampled and analyzed in more detail for its confirmation. Despite the poorly consolidated nature of the subsurface gossan, dry drilling was able to retrieve useful core material for geological and biological analysis. Lessons learned from this drilling simulation can guide the development of dry drilling and subsurface geological and biological analytical technologies for future Mars drilling missions.

The Subsurface Geology of Río Tinto: Material Examined During a Simulated Mars Drilling Mission for the Mars Astrobiology Research and Technology Experiment (MARTE)

NASA Astrophysics Data System (ADS)

Prieto-Ballesteros, Olga; Martínez-Frías, Jesús; Schutt, John; Sutter, Brad; Heldmann, Jennifer L.; Bell Johnson, Mary Sue; Battler, Melissa; Cannon, Howard; Gómez-Elvira, Javier; Stoker, Carol R.

2008-10-01

The 2005 Mars Astrobiology Research and Technology Experiment (MARTE) project conducted a simulated 1-month Mars drilling mission in the Río Tinto district, Spain. Dry robotic drilling, core sampling, and biological and geological analytical technologies were collectively tested for the first time for potential use on Mars. Drilling and subsurface sampling and analytical technologies are being explored for Mars because the subsurface is the most likely place to find life on Mars. The objectives of this work are to describe drilling, sampling, and analytical procedures; present the geological analysis of core and borehole material; and examine lessons learned from the drilling simulation. Drilling occurred at an undis closed location, causing the science team to rely only on mission data for geological and biological interpretations. Core and borehole imaging was used for micromorphological analysis of rock, targeting rock for biological analysis, and making decisions regarding the next day's drilling operations. Drilling reached 606 cm depth into poorly consolidated gossan that allowed only 35% of core recovery and contributed to borehole wall failure during drilling. Core material containing any indication of biology was sampled and analyzed in more detail for its confirmation. Despite the poorly consolidated nature of the subsurface gossan, dry drilling was able to retrieve useful core material for geological and biological analysis. Lessons learned from this drilling simulation can guide the development of dry drilling and subsurface geological and biological analytical technologies for future Mars drilling missions.

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic radioactive waste repository: 2. Application to a Canadian Shield environment

NASA Astrophysics Data System (ADS)

Park, Y.-J.; Cornaton, F. J.; Normani, S. D.; Sykes, J. F.; Sudicky, E. A.

2008-04-01

F. J. Cornaton et al. (2008) introduced the concept of lifetime expectancy as a performance measure of the safety of subsurface repositories, on the basis of the travel time for contaminants released at a certain point in the subsurface to reach the biosphere or compliance area. The methodologies are applied to a hypothetical but realistic Canadian Shield crystalline rock environment, which is considered to be one of the most geologically stable areas on Earth. In an approximately 10 × 10 × 1.5 km3 hypothetical study area, up to 1000 major and intermediate fracture zones are generated from surface lineament analyses and subsurface surveys. In the study area, mean and probability density of lifetime expectancy are analyzed with realistic geologic and hydrologic shield settings in order to demonstrate the applicability of the theory and the numerical model for optimally locating a deep subsurface repository for the safe storage of spent nuclear fuel. The results demonstrate that, in general, groundwater lifetime expectancy increases with depth and it is greatest inside major matrix blocks. Various sources and aspects of uncertainty are considered, specifically geometric and hydraulic parameters of permeable fracture zones. Sensitivity analyses indicate that the existence and location of permeable fracture zones and the relationship between fracture zone permeability and depth from ground surface are the most significant factors for lifetime expectancy distribution in such a crystalline rock environment. As a consequence, it is successfully demonstrated that the concept of lifetime expectancy can be applied to siting and performance assessment studies for deep geologic repositories in crystalline fractured rock settings.

Characterizing Long-Term Groundwater Conditions and Lithology for the Design of Large-Scale Borehole Heat Exchangers

NASA Astrophysics Data System (ADS)

Smith, David Charles

Construction of large scale ground coupled heat pump (GCHP) systems that operate with hundreds or even thousands of boreholes for the borehole heat exchangers (BHE) has increased in recent years with many coming on line in the past 10 years. Many large institutions are constructing these systems because of their ability to store energy in the subsurface for indoor cooling during the warm summer months and extract that energy for heating during the cool winter months. Despite the increase in GCHP system systems constructed, there have been few long term studies on how these large systems interact with the subsurface. The thermal response test (TRT) is the industry standard for determining the thermal properties of the rock and soil. The TRT is limited in that it can only be used to determine the effective thermal conductivity over the whole length of a single borehole at the time that it is administered. The TRT cannot account for long-term changes in the aquifer saturation, changes in groundwater flow, or characterize different rock and soil units by effectiveness for heat storage. This study established new methods and also the need for the characterization of the subsurface for the purpose of design and long-term monitoring for GCHP systems. These new methods show that characterizing the long-term changes in aquifer saturation and groundwater flow, and characterizing different rock and soil units are an important part of the design and planning process of these systems. A greater understanding of how large-scale GCHP systems interact with the subsurface will result in designs that perform more efficiently over a longer period of time and expensive modifications due to unforeseen changes in system performance will be reduced.

Aeromagnetic Map with Geology of the Los Angeles 30 x 60 Minute Quadrangle, Southern California

USGS Publications Warehouse

Langenheim, V.E.; Hildenbrand, T.G.; Jachens, R.C.; Campbell, R.H.; Yerkes, R.F.

2006-01-01

Introduction: An important objective of geologic mapping is to project surficial structures and stratigraphy into the subsurface. Geophysical data and analysis are useful tools for achieving this objective. This aeromagnetic anomaly map provides a three-dimensional perspective to the geologic mapping of the Los Angeles 30 by 60 minute quadrangle. Aeromagnetic maps show the distribution of magnetic rocks, primarily those containing magnetite (Blakely, 1995). In the Los Angeles quadrangle, the magnetic sources are Tertiary and Mesozoic igneous rocks and Precambrian crystalline rocks. Aeromagnetic anomalies mark abrupt spatial contrasts in magnetization that can be attributed to lithologic boundaries, perhaps caused by faulting of these rocks or by intrusive contacts. This aeromagnetic map overlain on geology, with information from wells and other geophysical data, provides constraints on the subsurface geology by allowing us to trace faults beneath surficial cover and estimate fault dip and offset. This map supersedes Langenheim and Jachens (1997) because of its digital form and the added value of overlaying the magnetic data on a geologic base. The geologic base for this map is from Yerkes and Campbell (2005); some of their subunits have been merged into one on this map.

Induction heaters used to heat subsurface formations

DOEpatents

Nguyen, Scott Vinh [Houston, TX; Bass, Ronald M [Houston, TX

2012-04-24

A heating system for a subsurface formation includes an elongated electrical conductor located in the subsurface formation. The electrical conductor extends between at least a first electrical contact and a second electrical contact. A ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300.degree. C.

The Nature and Subsurface Geometry of Late Holocene Coquina Rocks, Karaburun-Istanbul, NW Turkey

NASA Astrophysics Data System (ADS)

Ekinci, Y. L.; Demirci, A.; Erginal, A. E.; Kaya, H.; Ekinci, R.

2012-04-01

The so-called coquina defines moderately to hardly amalgamated shell debris by calcium carbonate cement. Even though its some depositional features are similar to intertidal beachrocks and carbonate-cemented dune rocks or eolianites, coquina occurs in shoal environments and is, in some cases, representative of tectonically uplifted coasts when it exposes remarkably above sea-level. In this study (supported financially by the Research Foundation of Çanakkale Onsekiz Mart University under project number COMUBAP: 2011/41), we discuss diagenetic features, radiocarbon age and subsurface geometry of coquina on Black Sea coast of Istanbul, NW Turkey, where such a Late Holocene occurrence has not been recorded so far. Having a visible thickness of 1 m, the coquina beds crop out on a slightly inclined wide beach formed mostly of shell fragments less than 5 cm in size. It contains calcite and aragonite as connective cement and broken or unbroken shells of Donacilla sp., Pecten glaucum and Ostrea edulis together with various foraminifera such as Elphidium macellum Ammonia compacta and coccolithophore Emiliania huxleyi. Radiocarbon ages from four bulk samples yielded calibrated ages ranging between 3.7 and 2.8 ka BP. Electrical resistivity tomography survey along three distinct transects perpendicular to the coastline were carried out in order to understand the thickness of coquina and its subsurface extensions along the beach. The apparent resistivity data were acquired along the survey lines of 21 electrodes with electrode spacing of 2 m, to give a total length of the line of 40 m. Dipole-dipole electrode configuration was used for 9 data levels. Topographic changes at the locations of each electrode points were determined by means of optical leveling technique for a more accurate calculation and interpretation. Apparent resistivity data were inverted by using 2D smoothness-constrained least squares algorithm. Similar electrical resistivity tomograms were obtained for three lines after the inversion process. The 2D resistivity images displayed a depth range of ~ 4.5 m and showed a strong resistivity contrast between coquina beach material (composed of shell fragments) and coquina rocks. Low resistivity values located at the northern lowermost part of tomograms point to seawater saturated material whilst the highest resistivity values indicate coquina beach material, having larger pore spaces between the grains. The northern uppermost parts of the tomograms, having a moderate resistivity range, mark the coquina rocks with a thickness of ~ 1-1.5 m. Additionally, the images also showed that the landward extension of the coquina rocks reaches ~ 22 m. Keywords: Coquina rocks, diagenetic features, radiocarbon age, subsurface geometry, İstanbul-Turkey

Aseptically Sampled Organics in Subsurface Rocks From the Mars Analog Rio Tinto Experiment: An Analog For The Search for Deep Subsurface Life on Mars.}

NASA Astrophysics Data System (ADS)

Bonaccorsi, R.; Stoker, C. R.

2005-12-01

The subsurface is the key environment for searching for life on planets lacking surface life. Subsurface ecosystems are of great relevance to astrobiology including the search for past/present life on Mars. The surface of Mars has conditions preventing current life but the subsurface might preserve organics and even host some life [1]. The Mars-Analog-Rio-Tinto-Experiment (MARTE) is performing a simulation of a Mars drilling experiment. This comprises conventional and robotic drilling of cores in a volcanically-hosted-massive-pyrite deposit [2] from the Iberian Pyritic Belt (IBP) and life detection experiments applying anti-contamination protocols (e.g., ATP Luminometry assay). The RT is considered an important analog of the Sinus Meridiani site on Mars and an ideal model analog for a deep subsurface Martian environment. Former results from MARTE suggest the existence of a relatively complex subsurface life including aerobic and anaerobic chemoautotrophs and strict anaerobic methanogens sustained by Fe and S minerals in anoxic conditions. A key requirement for the analysis of a subsurface sample on Mars is a set of simple tests that can help determine if the sample contains organic material of biological origin, and its potential for retaining definitive biosignatures. We report here on the presence of bulk organic matter Corg (0.03-0.05 Wt%), and Ntot (0.01-0.04 Wt%) and amount of measured ATP (Lightning MVP, Biocontrol) in weathered rocks (tuffs, gossan, pyrite stockwork from Borehole #8; >166m). This provides key insight on the type of trophic system sustaining the subsurface biosphere (i.e., heterotrophs vs. autotrophs) at RT. ATP data (Relative-Luminosity-Units, RLU) provide information on possible contamination and distribution of viable biomass with core depth (BH#8, and BH#7, ~3m). Avg. 153 RLU, i.e., surface vs. center of core, suggest that cleaness/sterility can be maintained when using a simple sterile protocol under field conditions. Results from this research will support future drilling mission planned on Mars. [1] Boston, P.J., et al., 1992. Icarus 95,300-308; [2] Leistel et al., 1998.

Organic and Inorganic Carbon in the Rio Tinto (Spain) Deep Subsurface System: a Possible Model for Subsurface Carbon and Lithoautotrophs on Mars.

NASA Astrophysics Data System (ADS)

Bonaccorsi, R.; Stoker, C. R.; MARTE Science Team

2007-12-01

The subsurface is the key environment for searching for life on planets lacking surface life. Subsurface ecosystems are of great relevance to astrobiology including the search for past/present life on Mars. Conditions on the Martian surface do not support biological activity but the subsurface might preserve organics and host subsurface life [1]. A key requirement for the analysis of subsurface samples on Mars is the ability to characterize organic vs. inorganic carbon pools. This information is needed to determine if the sample contains organic material of biological origin and/ or to establish if pools of inorganic carbon can support subsurface biospheres. The Mars Analog Rio Tinto Experiment (MARTE) performed deep drilling of cores i.e., down to 165-m depth, in a volcanically-hosted-massive-sulfide deposit at Rio Tinto, Spain, which is considered an important analog of the Sinus Meridiani site on Mars. Results from MARTE suggest the existence of a relatively complex subsurface life including aerobic and anaerobic chemoautotrophs, and strict anaerobic methanogens sustained by Fe and S minerals in anoxic conditions, which is an ideal model analog for a deep subsurface Martian environment. We report here on the distribution of organic (C-org: 0.01-0.3Wt% and inorganic carbon (IC = 0.01-7.0 Wt%) in a subsurface rock system including weathered/oxidized i.e., gossan, and unaltered pyrite stockwork. Cores were analyzed from 3 boreholes (BH-4, BH-7, and BH-8) that penetrated down to a depth of ~165 m into massive sulfide. Nearsurface phyllosilicate rich-pockets contain the highest amounts of organics (0.3Wt%) [2], while the deeper rocks contain the highest amount of carbonates. Assessing the amount of C pools available throughout the RT subsurface brings key insight on the type of trophic system sustaining its microbial ecosystem (i.e., heterotrophs vs. autotrophs) and the biogeochemical relationships that characterize a new type of subsurface biosphere at RT. This potentially novel biosphere on Earth could be used as a model to test for extant and extinct life on Mars. Furthermore, having found carbonates in an hyperacidic system (pH ~2.3) brings new insights on the possible occurrence of deep carbonates deposits under low-pH condition on Mars. [1] Boston, P.J., et al., 1992. Icarus 95,300-308; Bonaccorsi, Stoker and Sutter, 2007 Accepted with review in Astrobiology.

Implications of Earth analogs to Martian sulfate-filled Fractures

NASA Astrophysics Data System (ADS)

Holt, R. M.; Powers, D. W.

2017-12-01

Sulfate-filled fractures in fine-grained sediments on Mars are interpreted to be the result of fluid movement during deep burial. Fractures in the Dewey Lake (aka Quartermaster) Formation of southeastern New Mexico and west Texas are filled with gypsum that is at least partially synsedimentary. Sulfate in the Dewey Lake takes two principal forms: gypsum cement and gypsum (mainly fibrous) that fills fractures ranging from horizontal to vertical. Apertures are mainly mm-scale, though some are > 1 cm. The gypsum is antitaxial, fibrous, commonly approximately perpendicular to the wall rock, and displays suture lines and relics of the wall rock. Direct evidence of synsedimentary, near-surface origin includes gypsum intraclasts, intraclasts that include smaller intraclasts that contain gypsum clasts, intraclasts of gypsum with suture lines, gypsum concentrated in small desiccation cracks, and intraclasts that include fibrous gypsum-filled fractures that terminate at the eroded clast boundary. Dewey Lake fracture fillings suggest that their Martian analogs may also have originated in the shallow subsurface, shortly following the deposition of Martian sediments, in the presence of shallow aquifers.

Principal facts for gravity stations collected in 2010 from White Pine and Lincoln Counties, east-central Nevada

USGS Publications Warehouse

Mankinen, Edward A.; McKee, Edwin H.

2011-01-01

Increasing demands on the Colorado River system within the arid Southwestern United States have focused attention on finding new, alternative sources of water. Particular attention is being paid to the eastern Great Basin, where important ground-water systems occur within a regionally extensive sequence of Paleozoic carbonate rocks and in the Cenozoic basin-fill deposits that occur throughout the region. Geophysical investigations to characterize the geologic framework of aquifers in eastern Nevada and western Utah began in a series of cooperative agreements between the U.S. Geological Survey and the Southern Nevada Water Authority in 2003. These studies were intended to better understand the formation of basins, define their subsurface shape and depth, and delineate structures that may impede or enhance groundwater flow. We have combined data from gravity stations established during the current study with previously available data to produce an up-to-date isostatic-gravity map of the study area, using a gravity inversion method to calculate depths to pre-Cenozoic basement rock and to estimate alluvial/volcanic fill in the valleys.

A hydrogen-based subsurface microbial community dominated by methanogens

USGS Publications Warehouse

Chapelle, F.H.; O'Neil, Kyle; Bradley, P.M.; Methe, B.A.; Ciufo, S.A.; Knobel, L.L.; Lovley, D.R.

2002-01-01

The search for extraterrestrial life may be facilitated if ecosystems can be found on Earth that exist under conditions analogous to those present on other planets or moons. It has been proposed, on the basis of geochemical and thermodynamic considerations, that geologically derived hydrogen might support subsurface microbial communities on Mars and Europa in which methanogens form the base of the ecosystem1-5. Here we describe a unique subsurface microbial community in which hydrogen-consuming, methane-producing Archaea far outnumber the Bacteria. More than 90% of the 16s ribosomal DNA sequences recovered from hydrothermal waters circulating through deeply buried igneous rocks in Idaho are related to hydrogen-using methanogenic microorganisms. Geochemical characterization indicates that geothermal hydrogen, not organic carbon, is the primary energy source for this methanogen-dominated microbial community. These results demonstrate that hydrogen-based methanogenic communities do occur in Earth's subsurface, providing an analogue for possible subsurface microbial ecosystems on other planets.

New approaches in the indirect quantification of thermal rock properties in sedimentary basins: the well-log perspective

NASA Astrophysics Data System (ADS)

Fuchs, Sven; Balling, Niels; Förster, Andrea

2016-04-01

Numerical temperature models generated for geodynamic studies as well as for geothermal energy solutions heavily depend on rock thermal properties. Best practice for the determination of those parameters is the measurement of rock samples in the laboratory. Given the necessity to enlarge databases of subsurface rock parameters beyond drill core measurements an approach for the indirect determination of these parameters is developed, for rocks as well a for geological formations. We present new and universally applicable prediction equations for thermal conductivity, thermal diffusivity and specific heat capacity in sedimentary rocks derived from data provided by standard geophysical well logs. The approach is based on a data set of synthetic sedimentary rocks (clastic rocks, carbonates and evaporates) composed of mineral assemblages with variable contents of 15 major rock-forming minerals and porosities varying between 0 and 30%. Petrophysical properties are assigned to both the rock-forming minerals and the pore-filling fluids. Using multivariate statistics, relationships then were explored between each thermal property and well-logged petrophysical parameters (density, sonic interval transit time, hydrogen index, volume fraction of shale and photoelectric absorption index) on a regression sub set of data (70% of data) (Fuchs et al., 2015). Prediction quality was quantified on the remaining test sub set (30% of data). The combination of three to five well-log parameters results in predictions on the order of <15% for thermal conductivity and thermal diffusivity, and of <10% for specific heat capacity. Comparison of predicted and benchmark laboratory thermal conductivity from deep boreholes of the Norwegian-Danish Basin, the North German Basin, and the Molasse Basin results in 3 to 5% larger uncertainties with regard to the test data set. With regard to temperature models, the use of calculated TC borehole profiles approximate measured temperature logs with an error of <3°C along a 4 km deep profile. A benchmark comparison for thermal diffusivity and specific heat capacity is pending. Fuchs, Sven; Balling, Niels; Förster, Andrea (2015): Calculation of thermal conductivity, thermal diffusivity and specific heat capacity of sedimentary rocks using petrophysical well logs, Geophysical Journal International 203, 1977-2000, doi: 10.1093/gji/ggv403

"Sub-Surf Rocks"! An A-Level Resource Developed through an Industry-Education Collaboration

ERIC Educational Resources Information Center

Mather, Hazel

2012-01-01

A free internet resource called "Sub-Surf Rocks"! was launched in 2010. Its aim is to use seismic data obtained by the oil industry for enhancing the teaching of structural and economic geology at A-level (ages 16-18) in the UK. Seismic data gives a unique insight into the sub-surface and the many high-quality images coupled with…

Iberian Pyrite Belt Subsurface Life (IPBSL), a drilling project in a geochemical Mars terrestrial analogue

NASA Astrophysics Data System (ADS)

Amils, R.; Fernández-Remolar, D. C.; Parro, V.; Manfredi, J. A.; Timmis, K.; Oggerin, M.; Sánchez-Román, M.; López, F. J.; Fernández, J. P.; Omoregie, E.; Gómez-Ortiz, D.; Briones, C.; Gómez, F.; García, M.; Rodríguez, N.; Sanz, J. L.

2012-09-01

Iberian Pyrite Belt Subsurface Life (IPBSL) is a drilling project specifically designed to characterize the subsurface ecosystems operating in the Iberian Pyrite Belt (IPB), in the area of Peña de Hierro, and responsible of the extreme acidic conditions existing in the Rio Tinto basin [1]. Rio Tinto is considered a good geochemical terrestrial analogue of Mars [2, 3]. A dedicated geophysical characterization of the area selected two drilling sites (4) due to the possible existence of water with high ionic content (low resistivity). Two wells have been drilled in the selected area, BH11 and BH10, of depths of 340 and 620 meters respectively, with recovery of cores and generation of samples in anaerobic and sterile conditions. Preliminary results showed an important alteration of mineral structures associated with the presence of water, with production of expected products from the bacterial oxidation of pyrite (sulfates and ferric iron). Ion chromatography of water soluble compounds from uncontaminated samples showed the existence of putative electron donors (ferrous iron, nitrite in addition of the metal sulfides), electron acceptors (sulfate, nitrate, ferric iron) as well as variable concentration of metabolic organic acids (mainly acetate, formate, propionate and oxalate), which are strong signals of the presence of active subsurface ecosystem associated to the high sulfidic mineral content of the IPB. The system is driven by oxidants that appear to be provided by the rock matrix, only groundwater is needed to launch microbial metabolism. The geological, geomicrobiological and molecular biology analysis which are under way, should allow the characterization of this ecosystem of paramount interest in the design of an astrobiological underground Mars exploration mission in the near future.

Gas injection to inhibit migration during an in situ heat treatment process

DOEpatents

Kuhlman, Myron Ira; Vinegar; Harold J.; Baker, Ralph Sterman; Heron, Goren

2010-11-30

Methods of treating a subsurface formation are described herein. Methods for treating a subsurface treatment area in a formation may include introducing a fluid into the formation from a plurality of wells offset from a treatment area of an in situ heat treatment process to inhibit outward migration of formation fluid from the in situ heat treatment process.

Peroxy defects in Rocks and H2O2 formation on the early Earth

NASA Astrophysics Data System (ADS)

Gray, A.; Balk, M.; Mason, P.; Freund, F.; Rothschild, L.

2013-12-01

An oxygen-rich atmosphere appears to have been a prerequisite for complex life to evolve on Earth and possibly elsewhere in the Universe. The question is still shrouded in uncertainty how free oxygen became available on the early Earth. Here we study processes of peroxy defects in silicate minerals which, upon weathering, generate mobilized electronic charge carriers resulting in oxygen formation in an initially anoxic subsurface environment. Reactive Oxygen Species (ROS) are precursors to molecular oxygen during this process. Due to their toxicity they may have strongly influenced the evolution of life. ROS are generated during hydrolysis of peroxy defects, which consist of pairs of oxygen anions. A second pathway for formation occurs during (bio) transformations of iron sulphide minerals. ROS are produced and consumed by intracellular and extracellular reactions of Fe, Mn, C, N, and S species. We propose that despite an overall reducing or neutral oxidation state of the macroenvironment and the absence of free O2 in the atmosphere, microorganisms on the early Earth had to cope with ROS in their microenvironments. They were thus under evolutionary pressure to develop enzymatic and other defenses against the potentially dangerous, even lethal effects of ROS and oxygen. We have investigated how oxygen might be released through weathering and test microorganisms in contact with rock surfaces. Our results show how early Life might have adapted to oxygen. Early microorganisms must have "trained" to detoxify ROS prior to the evolution of aerobic metabolism and oxygenic photosynthesis. A possible way out of this dilemma comes from a study of igneous and high-grade metamorphic rocks, whose minerals contain a small but significant fraction of oxygen anions in the valence state 1- , forming peroxy links of the type O3Si-OO-SiO3 [1, 2]. As water hydrolyzes the peroxy links hydrogen peroxide, H2O2, forms. Continued experimental discovery of H2O2 formation at rock-water interfaces as part of stress-activated currents on the tectonically active Earth may help us better understand the oxidation of the early Earth and the evolution of early Life. [1] Balk et al. (2009) Earth and Planetary Science Letters 283, 87-92. [2] Grant, R. A. et al. (2011) Int. J. Environ. Res. Public Health 8, 1936-1956.

Late Noachian/Early Hesperian Ridge Network in Nili Fossae: Evidence for Water-Saturated Near-Surface Crust

NASA Astrophysics Data System (ADS)

Mustard, J. F.; Pascuzzo, A.

2017-12-01

The region north of the contact between Syrtis Major and the Isidis Basin is populated by thousands of ridges 100s of meters in length, up to a few 10s of meters high and 15-50 meters wide. The resistant ridges are being exhumed from weak early Noachian smectite-bearing host rocks. Hypotheses for the formation include igneous intrusion or fill, impact-induced breccia dikes and chemical alteration of pre-existing fracture planes or mineralized fracture planes through groundwater circulation (our preferred mode of formation). Mineralogic interpretations of visible-near infrared reflectance spectra from the CRISM instrument on MRO may be critical in interpreting the formation process. While most of the ridges are at the limit of CRISM's spatial resolution of 18 m/pixel, CRISM has a special observing mode which can increase the resolution in the along track observing (ATO) direction by a factor of 2-3 (e.g. 6 m). Using a combination of full resolution and one ATO observation, we have analyzed well-exposed ridges in the Nili Fossae region. Ridges are commonly exposed from beneath a distinctive mafic capping rock rich in olivine and variably altered to magnesite. Many of the ridges exhibit weaker smectite absorptions near 1.9 and 2.3 µm compared to the host rock but no additional spectral features are observed. One cause for weaker absorptions is grain size (i.e. solid rock shows weaker absorptions than its powdered equivalent). Alternatively the presence of a spectrally neutral cementing compound or mineral like quartz could lead to weaker features. Timing of ridge formation is constrained by two key stratigraphic makers. First the ridges were likely formed after the Isidis basin-forming event, 3.9 Ga, because many are observed between the 1st and 2nd rings of the basin structure and would not have survived the impact event otherwise. Second the ridges are exhumed from beneath a distinctive olivine-rich mafic cap unit with its emplacement dated to between the Isidis event and the opening of the Nili Fossae, which was within 200 Myr of the Isidis event. The ridges likely formed in the shallow crust as they terminate against the capping unit that was emplaced on the post-Isidis Noachian surface. This near-surface setting may have led to a sustained connection between the subsurface aqueous environments and the surface.

Wellhead with non-ferromagnetic materials

DOEpatents

Hinson, Richard A [Houston, TX; Vinegar, Harold J [Bellaire, TX

2009-05-19

Wellheads for coupling to a heater located in a wellbore in a subsurface formation are described herein. At least one wellhead may include a heater located in a wellbore in a subsurface formation; and a wellhead coupled to the heater. The wellhead may be configured to electrically couple the heater to one or more surface electrical components. The wellhead may include at least one non-ferromagnetic material such that ferromagnetic effects are inhibited in the wellhead. Systems and methods for using such wellheads for treating a subsurface formation are described herein.

Geological and Geochemical Controls on Subsurface Microbial Life in the Samail Ophiolite, Oman.

PubMed

Rempfert, Kaitlin R; Miller, Hannah M; Bompard, Nicolas; Nothaft, Daniel; Matter, Juerg M; Kelemen, Peter; Fierer, Noah; Templeton, Alexis S

2017-01-01

Microbial abundance and diversity in deep subsurface environments is dependent upon the availability of energy and carbon. However, supplies of oxidants and reductants capable of sustaining life within mafic and ultramafic continental aquifers undergoing low-temperature water-rock reaction are relatively unknown. We conducted an extensive analysis of the geochemistry and microbial communities recovered from fluids sampled from boreholes hosted in peridotite and gabbro in the Tayin block of the Samail Ophiolite in the Sultanate of Oman. The geochemical compositions of subsurface fluids in the ophiolite are highly variable, reflecting differences in host rock composition and the extent of fluid-rock interaction. Principal component analysis of fluid geochemistry and geologic context indicate the presence of at least four fluid types in the Samail Ophiolite ("gabbro," "alkaline peridotite," "hyperalkaline peridotite," and "gabbro/peridotite contact") that vary strongly in pH and the concentrations of H 2 , CH 4 , Ca 2+ , Mg 2+ , [Formula: see text], [Formula: see text], trace metals, and DIC. Geochemistry of fluids is strongly correlated with microbial community composition; similar microbial assemblages group according to fluid type. Hyperalkaline fluids exhibit low diversity and are dominated by taxa related to the Deinococcus-Thermus genus Meiothermus , candidate phyla OP1, and the family Thermodesulfovibrionaceae. Gabbro- and alkaline peridotite- aquifers harbor more diverse communities and contain abundant microbial taxa affiliated with Nitrospira , Nitrosospharaceae, OP3, Parvarcheota, and OP1 order Acetothermales. Wells that sit at the contact between gabbro and peridotite host microbial communities distinct from all other fluid types, with an enrichment in betaproteobacterial taxa. Together the taxonomic information and geochemical data suggest that several metabolisms may be operative in subsurface fluids, including methanogenesis, acetogenesis, and fermentation, as well as the oxidation of methane, hydrogen and small molecular weight organic acids utilizing nitrate and sulfate as electron acceptors. Dynamic nitrogen cycling may be especially prevalent in gabbro and alkaline peridotite fluids. These data suggest water-rock reaction, as controlled by lithology and hydrogeology, constrains the distribution of life in terrestrial ophiolites.

Geological and geochemical controls on subsurface microbial life in the Samail Ophiolite, Oman

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rempfert, Kaitlin R.; Miller, Hannah M.; Bompard, Nicolas

Microbial abundance and diversity in deep subsurface environments is dependent upon the availability of energy and carbon. However, supplies of oxidants and reductants capable of sustaining life within mafic and ultramafic continental aquifers undergoing low-temperature water-rock reaction are relatively unknown. We conducted an extensive analysis of the geochemistry and microbial communities recovered from fluids sampled from boreholes hosted in peridotite and gabbro in the Tayin block of the Samail Ophiolite in the Sultanate of Oman. The geochemical compositions of subsurface fluids in the ophiolite are highly variable, reflecting differences in host rock composition and the extent of fluid-rock interaction. Principal component analysis of fluid geochemistry and geologic context indicate the presence of at least four fluid types in the Samail Ophiolite (“gabbro,” “alkaline peridotite,” “hyperalkaline peridotite,” and “gabbro/peridotite contact”) that vary strongly in pH and the concentrations of H 2, CH 4, Ca 2+, Mg 2+, NO 3 more » $-$, SO$$2-\\atop{4}$$, trace metals, and DIC. Geochemistry of fluids is strongly correlated with microbial community composition; similar microbial assemblages group according to fluid type. Hyperalkaline fluids exhibit low diversity and are dominated by taxa related to the Deinococcus-Thermus genus Meiothermus, candidate phyla OP1, and the family Thermodesulfovibrionaceae. Gabbro- and alkaline peridotite- aquifers harbor more diverse communities and contain abundant microbial taxa affiliated with Nitrospira, Nitrosospharaceae, OP3, Parvarcheota, and OP1 order Acetothermales. Wells that sit at the contact between gabbro and peridotite host microbial communities distinct from all other fluid types, with an enrichment in betaproteobacterial taxa. Together the taxonomic information and geochemical data suggest that several metabolisms may be operative in subsurface fluids, including methanogenesis, acetogenesis, and fermentation, as well as the oxidation of methane, hydrogen and small molecular weight organic acids utilizing nitrate and sulfate as electron acceptors. Dynamic nitrogen cycling may be especially prevalent in gabbro and alkaline peridotite fluids. As a result, these data suggest water-rock reaction, as controlled by lithology and hydrogeology, constrains the distribution of life in terrestrial ophiolites.« less

Geological and Geochemical Controls on Subsurface Microbial Life in the Samail Ophiolite, Oman

PubMed Central

Rempfert, Kaitlin R.; Miller, Hannah M.; Bompard, Nicolas; Nothaft, Daniel; Matter, Juerg M.; Kelemen, Peter; Fierer, Noah; Templeton, Alexis S.

2017-01-01

Microbial abundance and diversity in deep subsurface environments is dependent upon the availability of energy and carbon. However, supplies of oxidants and reductants capable of sustaining life within mafic and ultramafic continental aquifers undergoing low-temperature water-rock reaction are relatively unknown. We conducted an extensive analysis of the geochemistry and microbial communities recovered from fluids sampled from boreholes hosted in peridotite and gabbro in the Tayin block of the Samail Ophiolite in the Sultanate of Oman. The geochemical compositions of subsurface fluids in the ophiolite are highly variable, reflecting differences in host rock composition and the extent of fluid-rock interaction. Principal component analysis of fluid geochemistry and geologic context indicate the presence of at least four fluid types in the Samail Ophiolite (“gabbro,” “alkaline peridotite,” “hyperalkaline peridotite,” and “gabbro/peridotite contact”) that vary strongly in pH and the concentrations of H2, CH4, Ca2+, Mg2+, NO3-, SO42-, trace metals, and DIC. Geochemistry of fluids is strongly correlated with microbial community composition; similar microbial assemblages group according to fluid type. Hyperalkaline fluids exhibit low diversity and are dominated by taxa related to the Deinococcus-Thermus genus Meiothermus, candidate phyla OP1, and the family Thermodesulfovibrionaceae. Gabbro- and alkaline peridotite- aquifers harbor more diverse communities and contain abundant microbial taxa affiliated with Nitrospira, Nitrosospharaceae, OP3, Parvarcheota, and OP1 order Acetothermales. Wells that sit at the contact between gabbro and peridotite host microbial communities distinct from all other fluid types, with an enrichment in betaproteobacterial taxa. Together the taxonomic information and geochemical data suggest that several metabolisms may be operative in subsurface fluids, including methanogenesis, acetogenesis, and fermentation, as well as the oxidation of methane, hydrogen and small molecular weight organic acids utilizing nitrate and sulfate as electron acceptors. Dynamic nitrogen cycling may be especially prevalent in gabbro and alkaline peridotite fluids. These data suggest water-rock reaction, as controlled by lithology and hydrogeology, constrains the distribution of life in terrestrial ophiolites. PMID:28223966

Geological and geochemical controls on subsurface microbial life in the Samail Ophiolite, Oman

DOE PAGES

Rempfert, Kaitlin R.; Miller, Hannah M.; Bompard, Nicolas; ...

2017-02-07

Microbial abundance and diversity in deep subsurface environments is dependent upon the availability of energy and carbon. However, supplies of oxidants and reductants capable of sustaining life within mafic and ultramafic continental aquifers undergoing low-temperature water-rock reaction are relatively unknown. We conducted an extensive analysis of the geochemistry and microbial communities recovered from fluids sampled from boreholes hosted in peridotite and gabbro in the Tayin block of the Samail Ophiolite in the Sultanate of Oman. The geochemical compositions of subsurface fluids in the ophiolite are highly variable, reflecting differences in host rock composition and the extent of fluid-rock interaction. Principal component analysis of fluid geochemistry and geologic context indicate the presence of at least four fluid types in the Samail Ophiolite (“gabbro,” “alkaline peridotite,” “hyperalkaline peridotite,” and “gabbro/peridotite contact”) that vary strongly in pH and the concentrations of H 2, CH 4, Ca 2+, Mg 2+, NO 3 more » $-$, SO$$2-\\atop{4}$$, trace metals, and DIC. Geochemistry of fluids is strongly correlated with microbial community composition; similar microbial assemblages group according to fluid type. Hyperalkaline fluids exhibit low diversity and are dominated by taxa related to the Deinococcus-Thermus genus Meiothermus, candidate phyla OP1, and the family Thermodesulfovibrionaceae. Gabbro- and alkaline peridotite- aquifers harbor more diverse communities and contain abundant microbial taxa affiliated with Nitrospira, Nitrosospharaceae, OP3, Parvarcheota, and OP1 order Acetothermales. Wells that sit at the contact between gabbro and peridotite host microbial communities distinct from all other fluid types, with an enrichment in betaproteobacterial taxa. Together the taxonomic information and geochemical data suggest that several metabolisms may be operative in subsurface fluids, including methanogenesis, acetogenesis, and fermentation, as well as the oxidation of methane, hydrogen and small molecular weight organic acids utilizing nitrate and sulfate as electron acceptors. Dynamic nitrogen cycling may be especially prevalent in gabbro and alkaline peridotite fluids. As a result, these data suggest water-rock reaction, as controlled by lithology and hydrogeology, constrains the distribution of life in terrestrial ophiolites.« less

Hydrogeology of south-central St Croix, US Virgin Islands

USGS Publications Warehouse

Graves, R.P.

1995-01-01

The subsurface geology of south-central St. Croix consists of alluvium and underlying carbonate rocks. The alluvial deposits consist of sand and gravel with cobbles and boulders and, locally, thin lenses of silt and clay. The carbonate rocks consist of the Oligocene to Middle Miocene age Jealousy formation, the Miocene and Pliocene are Kingshill Limestone, and the Pliocene and younger age Post-Kingshill Carbonates. Ground water occurs under water-table conditions in the alluvial, Post-Kingshill Carbonates, and Kingshill Limestone deposits. These deposits are hydraulically connected and are considered to be a single hydrologic unit. The top of the water-table aquifer can range from 5 to 68 feet below land surface. The top of the Jealousy Formation is considered to be the bottom of the water- table aquifer and generally is from 85 to greater than 120 feet below land surface. Aquifer yields in south- central St. Croix can range from less than 5 gallons per minute to 80 gallons per minute. The ground- water in the study area is of the sodium-chloride type. Ground-water samples collected from selected wells had chloride concentrations ranging from 64 to 4,400 milligrams per liter, and dissolved solid concen- trations ranging from 619 to 7,540 milligrams per liter. Connate water is suspected as being the source of sodium chloride in the ground water.

High-temperature water–rock interactions and hydrothermal environments in the chondrite-like core of Enceladus

PubMed Central

Sekine, Yasuhito; Shibuya, Takazo; Postberg, Frank; Hsu, Hsiang-Wen; Suzuki, Katsuhiko; Masaki, Yuka; Kuwatani, Tatsu; Mori, Megumi; Hong, Peng K.; Yoshizaki, Motoko; Tachibana, Shogo; Sirono, Sin-iti

2015-01-01

It has been suggested that Saturn's moon Enceladus possesses a subsurface ocean. The recent discovery of silica nanoparticles derived from Enceladus shows the presence of ongoing hydrothermal reactions in the interior. Here, we report results from detailed laboratory experiments to constrain the reaction conditions. To sustain the formation of silica nanoparticles, the composition of Enceladus' core needs to be similar to that of carbonaceous chondrites. We show that the presence of hydrothermal reactions would be consistent with NH3- and CO2-rich plume compositions. We suggest that high reaction temperatures (>50 °C) are required to form silica nanoparticles whether Enceladus' ocean is chemically open or closed to the icy crust. Such high temperatures imply either that Enceladus formed shortly after the formation of the solar system or that the current activity was triggered by a recent heating event. Under the required conditions, hydrogen production would proceed efficiently, which could provide chemical energy for chemoautotrophic life. PMID:26506464

High-temperature water-rock interactions and hydrothermal environments in the chondrite-like core of Enceladus.

PubMed

Sekine, Yasuhito; Shibuya, Takazo; Postberg, Frank; Hsu, Hsiang-Wen; Suzuki, Katsuhiko; Masaki, Yuka; Kuwatani, Tatsu; Mori, Megumi; Hong, Peng K; Yoshizaki, Motoko; Tachibana, Shogo; Sirono, Sin-iti

2015-10-27

It has been suggested that Saturn's moon Enceladus possesses a subsurface ocean. The recent discovery of silica nanoparticles derived from Enceladus shows the presence of ongoing hydrothermal reactions in the interior. Here, we report results from detailed laboratory experiments to constrain the reaction conditions. To sustain the formation of silica nanoparticles, the composition of Enceladus' core needs to be similar to that of carbonaceous chondrites. We show that the presence of hydrothermal reactions would be consistent with NH3- and CO2-rich plume compositions. We suggest that high reaction temperatures (>50 °C) are required to form silica nanoparticles whether Enceladus' ocean is chemically open or closed to the icy crust. Such high temperatures imply either that Enceladus formed shortly after the formation of the solar system or that the current activity was triggered by a recent heating event. Under the required conditions, hydrogen production would proceed efficiently, which could provide chemical energy for chemoautotrophic life.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Striolo, Alberto; Cole, David R.

Because of a number of technological advancements, unconventional hydrocarbons, and in particular shale gas, have transformed the US economy. Much is being learned, as demonstrated by the reduced cost of extracting shale gas in the US over the past five years. However, a number of challenges still need to be addressed. Many of these challenges represent grand scientific and technological tasks, overcoming which will have a number of positive impacts, ranging from the reduction of the environmental footprint of shale gas production to improvements and leaps forward in diverse sectors, including chemical manufacturing and catalytic transformations. This review addresses recentmore » advancements in computational and experimental approaches, which led to improved understanding of, in particular, structure and transport of fluids, including hydrocarbons, electrolytes, water, and CO 2 in heterogeneous subsurface rocks such as those typically found in shale formations. Finally, the narrative is concluded with a suggestion of a few research directions that, by synergistically combining computational and experimental advances, could allow us to overcome some of the hurdles that currently hinder the production of hydrocarbons from shale formations.« less

National assessment of geologic carbon dioxide storage resources: results

USGS Publications Warehouse

,

2013-01-01

In 2012, the U.S. Geological Survey (USGS) completed an assessment of the technically accessible storage resources (TASR) for carbon dioxide (CO2) in geologic formations underlying the onshore and State waters area of the United States. The formations assessed are at least 3,000 feet (914 meters) below the ground surface. The TASR is an estimate of the CO2 storage resource that may be available for CO2 injection and storage that is based on present-day geologic and hydrologic knowledge of the subsurface and current engineering practices. Individual storage assessment units (SAUs) for 36 basins were defined on the basis of geologic and hydrologic characteristics outlined in the assessment methodology of Brennan and others (2010, USGS Open-File Report 2010–1127) and the subsequent methodology modification and implementation documentation of Blondes, Brennan, and others (2013, USGS Open-File Report 2013–1055). The mean national TASR is approximately 3,000 metric gigatons (Gt). The estimate of the TASR includes buoyant trapping storage resources (BSR), where CO2 can be trapped in structural or stratigraphic closures, and residual trapping storage resources, where CO2 can be held in place by capillary pore pressures in areas outside of buoyant traps. The mean total national BSR is 44 Gt. The residual storage resource consists of three injectivity classes based on reservoir permeability: residual trapping class 1 storage resource (R1SR) represents storage in rocks with permeability greater than 1 darcy (D); residual trapping class 2 storage resource (R2SR) represents storage in rocks with moderate permeability, defined as permeability between 1 millidarcy (mD) and 1 D; and residual trapping class 3 storage resource (R3SR) represents storage in rocks with low permeability, defined as permeability less than 1 mD. The mean national storage resources for rocks in residual trapping classes 1, 2, and 3 are 140 Gt, 2,700 Gt, and 130 Gt, respectively. The known recovery replacement storage resource (KRRSR) is a conservative estimate that represents only the amount of CO2 at subsurface conditions that could replace the volume of known hydrocarbon production. The mean national KRRSR, determined from production volumes rather than the geologic model of buoyant and residual traps that make up TASR, is 13 Gt. The estimated storage resources are dominated by residual trapping class 2, which accounts for 89 percent of the total resources. The Coastal Plains Region of the United States contains the largest storage resource of any region. Within the Coastal Plains Region, the resources from the U.S. Gulf Coast area represent 59 percent of the national CO2 storage capacity.

Rock formation characterization for carbon dioxide geosequestration: 3D seismic amplitude and coherency anomalies, and seismic petrophysical facies classification, Wellington and Anson-Bates Fields, Kansas, USA

NASA Astrophysics Data System (ADS)

Ohl, Derek; Raef, Abdelmoneam

2014-04-01

Higher resolution rock formation characterization is of paramount priority, amid growing interest in injecting carbon dioxide, CO2, into subsurface rock formations of depeleting/depleted hydrocarbon reservoirs or saline aquifers in order to reduce emissions of greenhouse gases. In this paper, we present a case study for a Mississippian carbonate characterization integrating post-stack seismic attributes, well log porosities, and seismic petrophysical facies classification. We evaluated changes in petrophysical lithofacies and reveal structural facies-controls in the study area. Three cross-plot clusters in a plot of well log porosity and acoustic impedance corroborated a Neural Network petrophysical facies classification, which was based on training and validation utilizing three petrophysically-different wells and three volume seismic attributes, extracted from a time window including the wavelet of the reservoir-top reflection. Reworked lithofacies along small-throw faults has been revealed based on comparing coherency and seismic petrophysical facies. The main objective of this study is to put an emphasis on reservoir characterization that is both optimized for and subsequently benefiting from pilot tertiary CO2 carbon geosequestration in a depleting reservoir and also in the deeper saline aquifer of the Arbuckle Group, south central Kansas. The 3D seismic coherency attribute, we calculated from a window embracing the Mississippian top reflection event, indicated anomalous features that can be interpreted as a change in lithofacies or faulting effect. An Artificial Neural Network (ANN) lithofacies modeling has been used to better understand these subtle features, and also provide petrophysical classes, which will benefit flow-simulation modeling and/or time-lapse seismic monitoring feasibility analysis. This paper emphasizes the need of paying greater attention to small-scale features when embarking upon characterization of a reservoir or saline-aquifer for CO2 based carbon geosequestration.

Petroleum geochemistry of oils and rocks in Arctic National Wildlife Refuge, Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magoon, L.B.; Anders, D.E.

1987-05-01

Thirteen oil seeps or oil-stained outcrops in or adjacent to the coastal plain of the Arctic National Wildlife Refuge (ANWR) in northeastern Alaska indicate that commercial quantities of hydrocarbons may be present in the subsurface. The area is flanked by two important petroleum provinces: the Prudhoe Bay area on the west and the Mackenzie delta on the east. Organic carbon content (wt. %), organic matter type, and pyrolysis hydrocarbon yield show that rock units such as the Kingak Shale (average 1.3 wt. %), pebble shale unit (2.1 wt. %), and Canning Formation (1.9 wt. %) contain predominantly type III organicmore » matter. The exception is the Hue Shale (5.9 wt. %), which contains type II organic matter. Pre-Cretaceous rocks that crop out in the Brooks Range could not be adequately evaluated because of high thermal maturity. Thermal maturity thresholds for oil, condensate, and gas calculated from vitrinite reflectance gradients in the Point Thomson area are 4000, 7300, and 9330 m, respectively (12,000, 22,500, and 28,000 ft). Time-temperature index (TTI) calculations for the Beli-1 and Point Thomson-1 wells immediately west of ANWR indicate that maturity first occurred in the south and progressed north. The Cretaceous Hue Shale matured in the Beli-1 well during the Eocene and in the Point Thomson-1 well in the late Miocene to early Pliocene. In the Point Thomson area, the condensate and gas recovered from the Thomson sandstone and basement complex based on API gravity and gas/oil ratio (GOR) probably originated from the pebble shale unit, and on the same basis, the oil recovered from the Canning Formation probably originated from the Hue Shale. The gas recovered from the three wells in the Kavik area is probably thermal gas from overmature source rocks in the immediate area.« less

CO2 Driven Mineral Transformations in Fractured Reservoir

NASA Astrophysics Data System (ADS)

Schaef, T.

2015-12-01

Engineering fracture systems in low permeable formations to increase energy production, accelerate heat extraction, or to enhance injectivity for storing anthropogenic CO2, is a challenging endeavor. To complicate matters, caprocks, essential components of subsurface reservoirs, need to maintain their sealing integrity in this modified subsurface system. Supercritical CO2 (scCO2), a proposed non-aqueous based working fluid, is capable of driving mineral transformations in fracture environments. Water dissolution in scCO2 significantly impacts the reactivity of this fluid, largely due to the development of thin adsorbed H2O films on the surfaces of exposed rocks and minerals. Adsorbed H2O films are geochemically complex microenvironments that host mineral dissolution and precipitation processes that could be tailored to influence overall formation permeability. Furthermore, manipulating the composition of injected CO2 (e.g., moisture content and/or reactive gases such as O2, NOx, or SOx) could stimulate targeted mineral transformations that enhance or sustain reservoir performance. PNNL has developed specialized experimental techniques that can be used to characterize chemical reactions occurring between minerals and pressurized gases. For example, hydration of a natural shale sample (Woodford Shale) has been characterized by an in situ infrared spectroscopic technique as water partitions from the scCO2 onto the shale. Mineral dissolution and carbonate precipitation reactions were tracked by monitoring changes of Si-O and C-O stretching bands, respectively Structural changes indicated expandable clays in the shale such as montmorillonite are intercalated with scCO2, a process not observed with the non-expandable kaolinite component. Extreme scale ab initio molecular dynamics simulations were used in conjunction with model mineral systems to identify the driving force and mechanism of water films. They showed that the film nucleation and formation on minerals is driven by both enthalpic and entropic requirements. Collectively, the synergy between laboratory observations, state-of-the-art atomistic simulations and reservoir modeling has generated important insights for the design and engineering of subsurface reservoirs for CO2 storage and energy extraction.

Potential for Nitrogen Fixation and Nitrification in the Granite-Hosted Subsurface at Henderson Mine, CO

PubMed Central

Swanner, Elizabeth D.; Templeton, Alexis S.

2011-01-01

The existence of life in the deep terrestrial subsurface is established, yet few studies have investigated the origin of nitrogen that supports deep life. Previously, 16S rRNA gene surveys cataloged a diverse microbial community in subsurface fluids draining from boreholes 3000 feet deep at Henderson Mine, CO, USA (Sahl et al., 2008). The prior characterization of the fluid chemistry and microbial community forms the basis for the further investigation here of the source of NH4+. The reported fluid chemistry included N2, NH4+ (5–112 μM), NO2− (27–48 μM), and NO3− (17–72 μM). In this study, the correlation between low NH4+ concentrations in dominantly meteoric fluids and higher NH4+ in rock-reacted fluids is used to hypothesize that NH4+ is sourced from NH4+-bearing biotite. However, biotite samples from the host rocks and ore-body minerals were analyzed by Fourier transform infrared (FTIR) microscopy and none-contained NH4+. However, the nitrogenase-encoding gene nifH was successfully amplified from DNA of the fluid sample with high NH4+, suggesting that subsurface microbes have the capability to fix N2. If so, unregulated nitrogen fixation may account for the relatively high NH4+ concentrations in the fluids. Additionally, the amoA and nxrB genes for archaeal ammonium monooxygenase and nitrite oxidoreductase, respectively, were amplified from the high NH4+ fluid DNA, while bacterial amoA genes were not. Putative nitrifying organisms are closely related to ammonium-oxidizing Crenarchaeota and nitrite-oxidizing Nitrospira detected in other subsurface sites based upon 16S rRNA sequence analysis. Thermodynamic calculations underscore the importance of NH4+ as an energy source in a subsurface nitrification pathway. These results suggest that the subsurface microbial community at Henderson is adapted to the low nutrient and energy environment by their capability of fixing nitrogen, and that fixed nitrogen may support subsurface biomass via nitrification. PMID:22190904

A minimalistic microbial food web in an excavated deep subsurface clay rock.

PubMed

Bagnoud, Alexandre; de Bruijn, Ino; Andersson, Anders F; Diomidis, Nikitas; Leupin, Olivier X; Schwyn, Bernhard; Bernier-Latmani, Rizlan

2016-01-01

Clay rocks are being considered for radioactive waste disposal, but relatively little is known about the impact of microbes on the long-term safety of geological repositories. Thus, a more complete understanding of microbial community structure and function in these environments would provide further detail for the evaluation of the safety of geological disposal of radioactive waste in clay rocks. It would also provide a unique glimpse into a poorly studied deep subsurface microbial ecosystem. Previous studies concluded that microorganisms were present in pristine Opalinus Clay, but inactive. In this work, we describe the microbial community and assess the metabolic activities taking place within borehole water. Metagenomic sequencing and genome-binning of a porewater sample containing suspended clay particles revealed a remarkably simple heterotrophic microbial community, fueled by sedimentary organic carbon, mainly composed of two organisms: a Pseudomonas sp. fermenting bacterium growing on organic macromolecules and releasing organic acids and H2, and a sulfate-reducing Peptococcaceae able to oxidize organic molecules to CO(2). In Opalinus Clay, this microbial system likely thrives where pore space allows it. In a repository, this may occur where the clay rock has been locally damaged by excavation or in engineered backfills. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Molecular diversity of bacterial communities from subseafloor rock samples in a deep-water production basin in Brazil.

PubMed

von der Weid, Irene; Korenblum, Elisa; Jurelevicius, Diogo; Rosado, Alexandre Soares; Dino, Rodolfo; Sebastian, Gina Vasquez; Seldin, Lucy

2008-01-01

The deep subseafloor rock in oil reservoirs represents a unique environment in which a high oilcontamination and very low biomass can be observed. Sampling this environment has been a challenge owing to the techniques used for drilling and coring. In this study, the facilities developed by the Brazilian oil company PETROBRAS for accessing deep subsurface oil reservoirs were used to obtain rock samples at 2,822-2,828 m below the ocean floor surface from a virgin field located in the Atlantic Ocean, Rio de Janeiro. To address the bacterial diversity of these rock samples, PCR amplicons were obtained using the DNA from four core sections and universal primers for 16S rRNA and for APS reductase (aps) genes. Clone libraries were generated from these PCR fragments and 87 clones were sequenced. The phylogenetic analyses of the 16S rDNA clone libraries showed a wide distribution of types in the domain bacteria in the four core samples, and the majority of the clones were identified as belonging to Betaproteobacteria. The sulfate-reducing bacteria community could only be amplified by PCR in one sample, and all clones were identified as belonging to Gammaproteobacteria. For the first time, the bacterial community was assessed in such deep subsurface environment.

Biogeography of serpentinite-hosted microbial ecosystems

NASA Astrophysics Data System (ADS)

Brazelton, W.; Cardace, D.; Fruh-Green, G.; Lang, S. Q.; Lilley, M. D.; Morrill, P. L.; Szponar, N.; Twing, K. I.; Schrenk, M. O.

2012-12-01

Ultramafic rocks in the Earth's mantle represent a tremendous reservoir of carbon and reducing power. Upon tectonic uplift and exposure to fluid flow, serpentinization of these materials generates copious energy, sustains abiogenic synthesis of organic molecules, and releases hydrogen gas (H2). To date, however, the "serpentinite microbiome" is poorly constrained- almost nothing is known about the microbial diversity endemic to rocks actively undergoing serpentinization. Through the Census of Deep Life, we have obtained 16S rRNA gene pyrotag sequences from fluids and rocks from serpentinizing ophiolites in California, Canada, and Italy. The samples include high pH serpentinite springs, presumably representative of deeper environments within the ophiolite complex, wells which directly access subsurface aquifers, and rocks obtained from drill cores into serpentinites. These data represent a unique opportunity to examine biogeographic patterns among a restricted set of microbial taxa that are adapted to similar environmental conditions and are inhabiting sites with related geological histories. In general, our results point to potentially H2-utilizing Betaproteobacteria thriving in shallow, oxic-anoxic transition zones and anaerobic Clostridia thriving in anoxic, deep subsurface habitats. These general taxonomic and biogeochemical trends were also observed in seafloor Lost City hydrothermal chimneys, indicating that we are beginning to identify a core serpentinite microbial community that spans marine and continental settings.

Impact origin of the Avak Structure, Arctic Alaska, and genesis of the Barrow gas fields

USGS Publications Warehouse

Kirschner, C.E.; Grantz, A.; Mullen, M.W.

1992-01-01

Geophysical and subsurface geologic data suggest that the Avak structure, which underlies the Arctic Coastal Plain 12 km southeast of Barrow, Alaska, is a hypervelocity meteorite or comet impact structure. The structure is a roughly circular area of uplifted, chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km in diameter that is bounded by a ring of anastomosing, inwardly dipping, listric normal faults 12 km in diameter. Examination of cores from the Barrow gas fields and data concerning the age of the Avak structure suggest that the Avak meteorite struck a Late Cretaceous or Tertiary marine shelf or coastal plain between the Cenomanian (ca. 95 Ma), and deposition of the basal beds of the overlying late Pliocene and Quaternary Gubik Formation (ca. 3 Ma). -from Authors

Data acquisition and processing system and method for investigating sub-surface features of a rock formation

DOEpatents

Vu, Cung Khac; Nihei, Kurt; Johnson, Paul A; Guyer, Robert; Ten Cate, James A; Le Bas, Pierre-Yves; Larmat, Carene S

2015-01-27

A system and a method includes generating a first signal at a first frequency; and a second signal at a second frequency. Respective sources are positioned within the borehole and controllable such that the signals intersect in an intersection volume outside the borehole. A receiver detects a difference signal returning to the borehole generated by a non-linear mixing process within the intersection volume, and records the detected signal and stores the detected signal in a storage device and records measurement parameters including a position of the first acoustic source, a position of the second acoustic source, a position of the receiver, elevation angle and azimuth angle of the first acoustic signal and elevation angle and azimuth angle of the second acoustic signal.

Experimental evidence for chemo-mechanical coupling during carbon mineralization in ultramafic rocks

NASA Astrophysics Data System (ADS)

Lisabeth, H. P.; Zhu, W.; Kelemen, P. B.; Ilgen, A.

2017-09-01

Storing carbon dioxide in the subsurface as carbonate minerals has the benefit of long-term stability and immobility. Ultramafic rock formations have been suggested as a potential reservoir for this type of storage due to the availability of cations to react with dissolved carbon dioxide and the fast reaction rates associated with minerals common in ultramafic formations; however, the rapid reactions have the potential to couple with the mechanical and hydraulic behavior of the rocks and little is known about the extent and mechanisms of this coupling. In this study, we argue that the dissolution of primary minerals and the precipitation of secondary minerals along pre-existing fractures in samples lead to reductions in both the apparent Young's modulus and shear strength of aggregates, accompanied by reduction in permeability. Hydrostatic and triaxial deformation experiments were run on dunite samples saturated with de-ionized water and carbon dioxide-rich solutions while stress, strain, permeability and pore fluid chemistry were monitored. Sample microstructures were examined after reaction and deformation using scanning electron microscopy (SEM). The results show that channelized dissolution and carbonate mineral precipitation in the samples saturated with carbon dioxide-rich solutions modify the structure of grain boundaries, leading to the observed reductions in stiffness, strength and permeability. A geochemical model was run to help interpret fluid chemical data, and we find that the apparent reaction rates in our experiments are faster than rates calculated from powder reactors, suggesting mechanically enhanced reaction rates. In conclusion, we find that chemo-mechanical coupling during carbon mineralization in dunites leads to substantial modification of mechanical and hydraulic behavior that needs to be accounted for in future modeling efforts of in situ carbon mineralization projects.

Petroleum geology of the Southern Bida Basin, Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braide, S.P.

1990-05-01

The Southern Bida basin is located in central Nigeria and is a major sedimentary area with a 3.5-km-thick sedimentary fill. However, it is the least understood of Nigeria's sedimentary basins because serious oil and gas exploration has not been undertaken in the basin. The surrounding Precambrian basement rocks experienced severe deformation during the Late Panafrican phase (600 {plus minus} 150 m.y.), and developed megashears that were reactivated during the Late Campanian-Maestrichtian. The ensuing wrenchfault tectonics formed the basin. The sedimentary fill, which comprises the Lokoja Formation are chiefly, if not wholly, nonmarine clastics. These have been characterized into facies thatmore » rapidly change from basin margin to basin axis, and have undergone only relatively mild tectonic distortion. Subsurface relations of the Lokoja Formation are postulated from outcrop study. The potential source rocks are most likely within the basinal axis fill and have not been deeply buried based on vitrinite reflectance of <0.65%. These findings, with the largely nonmarine depositional environment, suggest gas and condensate are the most likely hydrocarbons. Alluvial fans and deltaic facies that interfinger with lacustrine facies provide excellent reservoir capabilities. Potential traps for hydrocarbon accumulation were formed by a northwest-southeast-trending Campanian-Maestrichtian wrench system with associated northeast-southwest-oriented normal faults. The traps include strata in alluvial fans, fractured uplifted basement blocks, and arched strata over uplifted blocks. However, the size of hydrocarbon accumulations could be limited to some extent by a lack of effective hydrocarbon seal, because the dominant seals in the formation are unconformities.« less

Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pyrak-Nolte, Laura J; DePaolo, Donald J.; Pietraß, Tanja

2015-05-22

From beneath the surface of the earth, we currently obtain about 80-percent of the energy our nation consumes each year. In the future we have the potential to generate billions of watts of electrical power from clean, green, geothermal energy sources. Our planet’s subsurface can also serve as a reservoir for storing energy produced from intermittent sources such as wind and solar, and it could provide safe, long-term storage of excess carbon dioxide, energy waste products and other hazardous materials. However, it is impossible to underestimate the complexities of the subsurface world. These complexities challenge our ability to acquire themore » scientific knowledge needed for the efficient and safe exploitation of its resources. To more effectively harness subsurface resources while mitigating the impacts of developing and using these resources, the U.S. Department of Energy established SubTER – the Subsurface Technology and Engineering RD&D Crosscut team. This DOE multi-office team engaged scientists and engineers from the national laboratories to assess and make recommendations for improving energy-related subsurface engineering. The SubTER team produced a plan with the overall objective of “adaptive control of subsurface fractures and fluid flow.”This plan revolved around four core technological pillars—Intelligent Wellbore Systems that sustain the integrity of the wellbore environment; Subsurface Stress and Induced Seismicity programs that guide and optimize sustainable energy strategies while reducing the risks associated with subsurface injections; Permeability Manipulation studies that improve methods of enhancing, impeding and eliminating fluid flow; and New Subsurface Signals that transform our ability to see into and characterize subsurface systems. The SubTER team developed an extensive R&D plan for advancing technologies within these four core pillars and also identified several areas where new technologies would require additional basic research. In response, the Office of Science, through its Office of Basic Energy Science (BES), convened a roundtable consisting of 15 national lab, university and industry geoscience experts to brainstorm basic research areas that underpin the SubTER goals but are currently underrepresented in the BES research portfolio. Held in Germantown, Maryland on May 22, 2015, the round-table participants developed a basic research agenda that is detailed in this report. Highlights include the following: -A grand challenge calling for advanced imaging of stress and geological processes to help understand how stresses and chemical substances are distributed in the subsurface—knowledge that is critical to all aspects of subsurface engineering; -A priority research direction aimed at achieving control of fluid flow through fractured media; -A priority research direction aimed at better understanding how mechanical and geochemical perturbations to subsurface rock systems are coupled through fluid and mineral interactions; -A priority research direction aimed at studying the structure, permeability, reactivity and other properties of nanoporous rocks, like shale, which have become critical energy materials and exhibit important hallmarks of mesoscale materials; -A cross-cutting theme that would accelerate development of advanced computational methods to describe heterogeneous time-dependent geologic systems that could, among other potential benefits, provide new and vastly improved models of hydraulic fracturing and its environmental impacts; -A cross-cutting theme that would lead to the creation of “geo-architected materials” with controlled repeatable heterogeneity and structure that can be tested under a variety of thermal, hydraulic, chemical and mechanical conditions relevant to subsurface systems; -A cross-cutting theme calling for new laboratory studies on both natural and geo-architected subsurface materials that deploy advanced high-resolution 3D imaging and chemical analysis methods to determine the ;rates and mechanisms of fluid-rock processes, and to test predictive models of such phenomena. Many of the key energy challenges of the future demand a greater understanding of the subsurface world in all of its complexity. This greater under- standing will improve the ability to control and manipulate the subsurface world in ways that will benefit both the economy and the environment. This report provides specific basic research pathways to address some of the most fundamental issues of energy-related subsurface engineering.« less

Modeling of Composite Scenes Using Wires, Plates and Dielectric Parallelized (WIPL-DP)

DTIC Science & Technology

2006-06-01

formation and solves the data communications problem. The ability to perform subsurface imaging to depths of 200’ have already been demonstrated by...perform subsurface imaging to depths of 200’ have already been demonstrated by Brown in [3] and presented in Figure 3 above. Furthermore, reference [3...transmitter platform for use in image formation and solves the data communications problem. The ability to perform subsurface imaging to depths of 200

Long-term predictions of minewater geothermal systems heat resources

NASA Astrophysics Data System (ADS)

Harcout-Menou, Virginie; de ridder, fjo; laenen, ben; ferket, helga

2014-05-01

Abandoned underground mines usually flood due to the natural rise of the water table. In most cases the process is relatively slow giving the mine water time to equilibrate thermally with the the surrounding rock massif. Typical mine water temperature is too low to be used for direct heating, but is well suited to be combined with heat pumps. For example, heat extracted from the mine can be used during winter for space heating, while the process could be reversed during summer to provide space cooling. Altough not yet widely spread, the use of low temperature geothermal energy from abandoned mines has already been implemented in the Netherlands, Spain, USA, Germany and the UK. Reliable reservoir modelling is crucial to predict how geothermal minewater systems will react to predefined exploitation schemes and to define the energy potential and development strategy of a large-scale geothermal - cold/heat storage mine water systems. However, most numerical reservoir modelling software are developed for typical environments, such as porous media (a.o. many codes developed for petroleum reservoirs or groundwater formations) and cannot be applied to mine systems. Indeed, mines are atypical environments that encompass different types of flow, namely porous media flow, fracture flow and open pipe flow usually described with different modelling codes. Ideally, 3D models accounting for the subsurface geometry, geology, hydrogeology, thermal aspects and flooding history of the mine as well as long-term effects of heat extraction should be used. A new modelling approach is proposed here to predict the long-term behaviour of Minewater geothermal systems in a reactive and reliable manner. The simulation method integrates concepts for heat and mass transport through various media (e.g., back-filled areas, fractured rock, fault zones). As a base, the standard software EPANET2 (Rossman 1999; 2000) was used. Additional equations for describing heat flow through the mine (both through open pipes and from the rock massif) have been implemented. Among others, parametric methods are used to bypass some shortcomings in the physical models used for the subsurface. The advantage is that the complete geometry of the mine workings can be integrated and that computing is fast enough to allow implementing and testing several scenarios (e.g. contributions from fault zones, different assumptions about the actual status of shafts, drifts and mined out areas) in an efficient way (Ferket et al., 2011). EPANET allows to incorporate the full complexity of the subsurface mine structure. As a result, the flooded mine is considered as a network of pipes, each with a custom-defined diameter, length and roughness.

Astrobiology Training in Lava Tubes (ATiLT): Characterizing coralloid speleothems in basaltic lava tubes as a Mars analogue

NASA Astrophysics Data System (ADS)

Ni, J.; Leveille, R. J.; Douglas, P.

2017-12-01

Coralloid speleothems or cave corals are small mineralised nodes that can take a variety of forms, and which develop through groundwater seepage and water-rock interaction in caves. They are found commonly on Earth in a plethora of caves, including lava tubes. Since lava tubes have been identified on the surface of Mars from remotely sensed images, there has been interest in studying Earth's lava tube systems as an analogue for understanding Martian lava environments. If cave minerals were found on Mars, they could indicate past or present water-rock interaction in the Martian subsurface. Martian lava tubes could also provide insights into habitable subsurface environments as well as conditions favourable for the synthesis and preservation of biosignatures. One of the aims of the Astrobiology Training in Lava Tubes (ATiLT) project is to analyze biosignatures and paleoenvironmental indicators in secondary cave minerals, which will be looked at in-situ and compared to collected field samples. In this study, secondary mineralization in lava cave systems from Lava Beds National Monument, CA is examined. In the field, coralloid speleothems have been observed growing on all surfaces of the caves, including cave ceilings, floors, walls and overhangs. They are also observed growing adjacent to biofilms, which sometimes fill in the cracks of the coralloid nodes. Preliminary results show the presence of opal, calcite, quartz and other minor minerals in the speleothems. This study seeks to understand the formation mechanism and source of these secondary minerals, as well as determine their possible relation to the biofilms. This will be done through the analysis of the water chemistry, isotope geochemistry and microscale mineralogy.

Time-Lapse Seismic Monitoring and Performance Assessment of CO 2 Sequestration in Hydrocarbon Reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Datta-Gupta, Akhil

Carbon dioxide sequestration remains an important and challenging research topic as a potentially viable approach for mitigating the effects of greenhouse gases on global warming (e.g., Chu and Majumdar, 2012; Bryant, 2007; Orr, 2004; Hepple and Benson, 2005; Bachu, 2003; Grimston et al., 2001). While CO 2 can be sequestered in oceanic or terrestrial biomass, the most mature and effective technology currently available is sequestration in geologic formations, especially in known hydrocarbon reservoirs (Barrufet et al., 2010; Hepple and Benson, 2005). However, challenges in the design and implementation of sequestration projects remain, especially over long time scales. One problem ismore » that the tendency for gravity override caused by the low density and viscosity of CO 2. In the presence of subsurface heterogeneity, fractures and faults, there is a significant risk of CO 2 leakage from the sequestration site into overlying rock compared to other liquid wastes (Hesse and Woods, 2010; Ennis-King and Patterson, 2002; Tsang et al., 2002). Furthermore, the CO 2 will likely interact chemically with the rock in which it is stored, so that understanding and predicting its transport behavior during sequestration can be complex and difficult (Mandalaparty et al., 2011; Pruess et al., 2003). Leakage of CO 2 can lead to such problems as acidification of ground water and killing of plant life, in addition to contamination of the atmosphere (Ha-Duong, 2003; Gasda et al., 2004). The development of adequate policies and regulatory systems to govern sequestration therefore requires improved characterization of the media in which CO 2 is stored and the development of advanced methods for detecting and monitoring its flow and transport in the subsurface (Bachu, 2003).« less

Investigation of Reactions between Glauconite and Carbon Dioxide, with Implications for Carbon Sequestration

NASA Astrophysics Data System (ADS)

Nguyen, A. V.; Gabitov, R. I.; Beckingham, L. E.; Toghiani, H.; Fei, Y.; Kirkland, B. L.

2017-12-01

Mineral trapping is one potentially effective technology for long-term storage of carbon dioxide in a subsurface environment that has high temperature and pressure. Conceptually, upon injection of CO2 as a supercritical fluid into geological formations, the CO2 will react with the host rock to form a secondary carbonate mineral that is stable, thus creating a long-term carbon sink under thermodynamic condition of the reaction. Previous studies have demonstrated crystallization of magnesite by reactivity of CO2 and olivine-bearing basalt. Glauconite, a Fe/Ca/Mg bearing aluminosilicate mineral, a potential candidate for reaction with CO2 is common in sedimentary rock formations. The objectives of this study are to 1) develop a protocol for testing mineral trapping in the subsurface and 2) use that protocol to test the reactivity and effectiveness of the mineral glauconite in carbon sequestration. A sample from the Cambrian Riley Formation of Central Texas was selected for this study because it is extremely rich in glauconite. Mineral composition of the powdered sample was investigated by X-ray diffraction (XRD), which revealed that the glauconitic sandstone contains glauconite 20.4%, quartz 71%, and celadonite 8.6%. In the first experiment, 1.5 g of 0.01- 0.5 cm diameter grains reacted with a supercritical CO2 fluid in 30 g of sea water. The laboratory experiment was conducted in a stainless steel vessel in situ reservoir conditions at 120 degrees Celsius and 100 bars. After CO2 injection, pH of the brine decreased from 8.23 to 7. Scanning electron microscopy (SEM) and X-ray diffraction method showed no carbonate formed after 10 days of reaction. However, further experimental modifications facilitated formation of calcite at higher pH. In the second experiment, 0.7 g of 10-75 μm grains presumably reacted with CO2 formed by ammonium carbonate decomposition in a brine of NaCl 0.5 and CaCl2 0.25M; pH after the end of experiment was 7.74. The autoclave was set at 120 degrees Celsius and pressure of saturated water vapour for 14 days. XRD and EDS confirmed the presence of calcite in the sample after the treatment. This material is based upon work supported by the Department of Energy National Energy Technology Laboratory under the Southern States Energy Board's Cooperative Agreement Award Number DE-FE0029465.

Magnetic signatures of the orogenic crust of the Patagonian Andes with implication for planetary exploration

NASA Astrophysics Data System (ADS)

Díaz Michelena, Marina; Kilian, Rolf

2015-11-01

The Patagonian Andes represent a good scenario of study because they have outcrops of diverse plutonic rocks representative of an orogenic crust on Earth and other planets. Furthermore, metamorphic surface rocks provide a window into deeper crustal lithologies. In such remote areas, satellite and aerial magnetic surveys could provide important geological information concerning exposed and not exposed rocks, but they integrate the magnetic anomalies in areas of kilometres. For the southernmost Andes long wavelength satellite data show clear positive magnetic anomalies (>+100 nT) for the Patagonian Batholith (PB), similar as parts of the older martian crust. This integrated signal covers regions with different ages and cooling histories during magnetic reversals apart from the variability of the rocks. To investigate the complex interplay of distinct magnetic signatures at short scale, we have analysed local magnetic anomalies across this orogen at representative sites by decimeter-scale magnetic ground surveys. As expected, the investigated sites have positive and negative local anomalies. They are related to surface and subsurface rocks, and their different formation and alternation processes including geomagnetic inversions, distinct Curie depths of the magnetic carriers, intracrustal deformation among other factors. Whole rock chemistry (ranging from 45 to >80 wt.% SiO2 and from 1 to 18 wt.% FeOtot.), magnetic characteristics (susceptibilities, magnetic remanence and Königsberger ratios) as well as the composition and texture of the magnetic carriers have been investigated for representative rocks. Rocks of an ultramafic to granodioritic intrusive suite of the western and central PB contain titanomagnetite as major magnetic carrier. Individual magnetic signatures of these plutonic rocks reflect their single versus multidomain status, complex exolution processes with ilmenite lamella formations and the stoichiometric proportions of Cr, Fe and Ti in the oxides. At the eastern margin of the PB the investigated plutons and mafic dykes have been emplaced and equilibrated at 4-6 km depth. They do not contain magnetite but include variable amounts of ferrimagnetic monoclinic C4 pyrrhotite, which was formed along fractures zones by a hydrothermal gold-bearing mineralisation. The intensity of their positive magnetic anomalies (up to +220 nT) is well correlated with the amount of pyrrhotite (1-4 vol.%). In all cases, high resolution ground surveys variations of the magnetic signature down to 20 nT could be used to clearly distinguish different rock types on a decimeter scale. Vector magnetometer MOURA designed for martian exploration was successfully used for these surveys and provides results comparable to a commonly used caesium scalar magnetometer. This is important for near future ground surveys on Mars and the Moon.

High concentrations of manganese and sulfur in deposits on Murray Ridge, Endeavour Crater, Mars

USGS Publications Warehouse

Arvidson, Raymond E.; Squyres, Steven W.; Morris, Richard V.; Knoll, Andrew H.; Gellert, Ralf; Clark, Benton C.; Catalano, Jeffrey G.; Jolliff, Bradley L.; McLennan, Scott M.; Herkenhoff, Kenneth E.; VanBommel, Scott; Mittelfehldt, David W.; Grotzinger, John P.; Guinness, Edward A.; Johnson, Jeffrey R.; Bell, James F.; Farrand, William H.; Stein, Nathan; Fox, Valerie K.; Golombek, Matthew P.; Hinkle, Margaret A. G.; Calvin, Wendy M.; de Souza, Paulo A.

2016-01-01

Mars Reconnaissance Orbiter HiRISE images and Opportunity rover observations of the ~22 km wide Noachian age Endeavour Crater on Mars show that the rim and surrounding terrains were densely fractured during the impact crater-forming event. Fractures have also propagated upward into the overlying Burns formation sandstones. Opportunity’s observations show that the western crater rim segment, called Murray Ridge, is composed of impact breccias with basaltic compositions, as well as occasional fracture-filling calcium sulfate veins. Cook Haven, a gentle depression on Murray Ridge, and the site where Opportunity spent its sixth winter, exposes highly fractured, recessive outcrops that have relatively high concentrations of S and Cl, consistent with modest aqueous alteration. Opportunity’s rover wheels serendipitously excavated and overturned several small rocks from a Cook Haven fracture zone. Extensive measurement campaigns were conducted on two of them: Pinnacle Island and Stuart Island. These rocks have the highest concentrations of Mn and S measured to date by Opportunity and occur as a relatively bright sulfate-rich coating on basaltic rock, capped by a thin deposit of one or more dark Mn oxide phases intermixed with sulfate minerals. We infer from these unique Pinnacle Island and Stuart Island rock measurements that subsurface precipitation of sulfate-dominated coatings was followed by an interval of partial dissolution and reaction with one or more strong oxidants (e.g., O2) to produce the Mn oxide mineral(s) intermixed with sulfate-rich salt coatings. In contrast to arid regions on Earth, where Mn oxides are widely incorporated into coatings on surface rocks, our results demonstrate that on Mars the most likely place to deposit and preserve Mn oxides was in fracture zones where migrating fluids intersected surface oxidants, forming precipitates shielded from subsequent physical erosion.

The influence of open fracture anisotropy on CO2 movement within geological storage complexes

NASA Astrophysics Data System (ADS)

Bond, C. E.; Wightman, R.; Ringrose, P. S.

2012-12-01

Carbon mitigation through the geological storage of carbon dioxide is dependent on the ability of geological formations to store CO2 trapping it within a geological storage complex. Secure long-term containment needs to be demonstrated, due to both political and social drivers, meaning that this containment must be verifiable over periods of 100-105 years. The effectiveness of sub-surface geological storage systems is dependent on trapping CO2 within a volume of rock and is reliant on the integrity of the surrounding rocks, including their chemical and physical properties, to inhibit migration to the surface. Oil and gas reservoir production data, and field evidence show that fracture networks have the potential to act as focused pathways for fluid movement. Fracture networks can allow large volumes of fluid to migrate to the surface within the time scales of interest. In this paper we demonstrate the importance of predicting the effects of fracture networks in storage, using a case study from the In Salah CO2 storage site, and show how the fracture permeability is closely controlled by the stress regime that determines the open fracture network. Our workflow combines well data of imaged fractures, with a discrete fracture network (DFN) model of tectonically induced fractures, within the horizon of interest. The modelled and observed fractures have been compared and combined with present day stress data to predict the open fracture network and its implications for anisotropic movement of CO2 in the sub-surface. The created fracture network model has been used to calculate the 2D permeability tensor for the reservoir for two scenarios: 1) a model in which all fractures are permeable, based on the whole DFN model and 2) those fractures determined to be in dilatational failure under the present day stress regime, a sub-set of the DFN. The resulting permeability anisotropy tensors show distinct anisotropies for the predicted CO2 movement within the reservoir. These predictions have been compared with InSAR imagery of surface uplift, used as an indicator of fluid pressure and movement in the sub-surface, around the CO2 injection wells. The analysis shows that the permeability tensor with the greatest anisotropy, that for the DFN sub-set of open fractures, matches well with the anisotropy in surface uplift imaged by InSAR. We demonstrate that predicting fracture networks alone does not predict fluid movement in the sub-surface, and that fracture permeability is closely controlled by the stress regime that determines the open fracture network. Our results show that a workflow of fracture network prediction combined with present day stress analysis can be used to successfully predict CO2 movement in the sub-surface at an active injection site.

Hydrology of the solid waste burial ground as related to potential migration of radionuclides, Idaho National Engineering Laboratory

USGS Publications Warehouse

Barraclough, Jack T.; Robertson, J.B.; Janzer, V.J.; Saindon, L.G.

1976-01-01

A study was made (1970-1974) to evaluate the geohydrologic and geochemical controls on subsurface migration of radionuclides from pits and trenches in the Idaho National Engineering Laboratory (INEL) solid waste burial ground and to determine the existence and extent of radionuclide migration from the burial ground. A total of about 1,700 sediment, rock, and water samples were collected from 10 observation wells drilled in and near the burial ground of Idaho National Engineering Laboratory, formerly the National Reactor Testing Station (NRTS). Within the burial ground area, the subsurface rocks are composed principally of basalt. Wind- and water-deposited sediments occur at the surface and in beds between the thicker basalt zones. Two principal sediment beds occur at about 110 feet and 240 feet below the land surface. The average thickness of the surficial sedimentary layer is about 15 feet while that of the two principal subsurface layers is 13 and 14 feet, respectively. The water table in the aquifer beneath the burial ground is at a depth of about 580 feet. Fission, activation, and transuranic elements were detected in some of the samples from the 110- and 240-foot sedimentary layers. (Woodard-USGS)

Deformation band clusters on Mars and implications for subsurface fluid flow

USGS Publications Warehouse

Okubo, C.H.; Schultz, R.A.; Chan, M.A.; Komatsu, G.

2009-01-01

High-resolution imagery reveals unprecedented lines of evidence for the presence of deformation band clusters in layered sedimentary deposits in the equatorial region of Mars. Deformation bands are a class of geologic structural discontinuity that is a precursor to faults in clastic rocks and soils. Clusters of deformation bands, consisting of many hundreds of individual subparallel bands, can act as important structural controls on subsurface fluid flow in terrestrial reservoirs, and evidence of diagenetic processes is often preserved along them. Deformation band clusters are identified on Mars based on characteristic meter-scale architectures and geologic context as observed in data from the High-Resolution Imaging Science Experiment (HiRISE) camera. The identification of deformation band clusters on Mars is a key to investigating the migration of fluids between surface and subsurface reservoirs in the planet's vast sedimentary deposits. Similar to terrestrial examples, evidence of diagenesis in the form of light- and dark-toned discoloration and wall-rock induration is recorded along many of the deformation band clusters on Mars. Therefore, these structures are important sites for future exploration and investigations into the geologic history of water and water-related processes on Mars. ?? 2008 Geological Society of America.

Area 2: Inexpensive Monitoring and Uncertainty Assessment of CO2 Plume Migration using Injection Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Srinivasan, Sanjay

2014-09-30

In-depth understanding of the long-term fate of CO₂ in the subsurface requires study and analysis of the reservoir formation, the overlaying caprock formation, and adjacent faults. Because there is significant uncertainty in predicting the location and extent of geologic heterogeneity that can impact the future migration of CO₂ in the subsurface, there is a need to develop algorithms that can reliably quantify this uncertainty in plume migration. This project is focused on the development of a model selection algorithm that refines an initial suite of subsurface models representing the prior uncertainty to create a posterior set of subsurface models thatmore » reflect injection performance consistent with that observed. Such posterior models can be used to represent uncertainty in the future migration of the CO₂ plume. Because only injection data is required, the method provides a very inexpensive method to map the migration of the plume and the associated uncertainty in migration paths. The model selection method developed as part of this project mainly consists of assessing the connectivity/dynamic characteristics of a large prior ensemble of models, grouping the models on the basis of their expected dynamic response, selecting the subgroup of models that most closely yield dynamic response closest to the observed dynamic data, and finally quantifying the uncertainty in plume migration using the selected subset of models. The main accomplishment of the project is the development of a software module within the SGEMS earth modeling software package that implements the model selection methodology. This software module was subsequently applied to analyze CO₂ plume migration in two field projects – the In Salah CO₂ Injection project in Algeria and CO₂ injection into the Utsira formation in Norway. These applications of the software revealed that the proxies developed in this project for quickly assessing the dynamic characteristics of the reservoir were highly efficient and yielded accurate grouping of reservoir models. The plume migration paths probabilistically assessed by the method were confirmed by field observations and auxiliary data. The report also documents the application of the software to answer practical questions such as the optimum location of monitoring wells to reliably assess the migration of CO₂ plume, the effect of CO₂-rock interactions on plume migration and the ability to detect the plume under those conditions and the effect of a slow, unresolved leak on the predictions of plume migration.« less

Informing geobiology through GIS site suitability analysis: locating springs in mantle units of ophiolites

NASA Astrophysics Data System (ADS)

Bowman, A.; Cardace, D.; August, P.

2012-12-01

Springs sourced in the mantle units of ophiolites serve as windows to the deep biosphere, and thus hold promise in elucidating survival strategies of extremophiles, and may also inform discourse on the origin of life on Earth. Understanding how organisms can survive in extreme environments provides clues to how microbial life responds to gradients in pH, temperature, and oxidation-reduction potential. Spring locations associated with serpentinites have traditionally been located using a variety of field techniques. The aqueous alteration of ultramafic rocks to serpentinites is accompanied by the production of very unusual formation fluids, accessed by drilling into subsurface flow regimes or by sampling at related surface springs. The chemical properties of these springs are unique to water associated with actively serpentinizing rocks; they reflect a reducing subsurface environment reacting at low temperatures producing high pH, Ca-rich formation fluids with high dissolved hydrogen and methane. This study applies GIS site suitability analysis to locate high pH springs upwelling from Coast Range Ophiolite serpentinites in Northern California. We used available geospatial data (e.g., geologic maps, topography, fault locations, known spring locations, etc.) and ArcGIS software to predict new spring localities. Important variables in the suitability model were: (a) bedrock geology (i.e., unit boundaries and contacts for peridotite, serpentinite, possibly pyroxenite, or chromite), (b) fault locations, (c) regional data for groundwater characteristics such as pH, Ca2+, and Mg2+, and (d) slope-aspect ratio. The GIS model derived from these geological and environmental data sets predicts the latitude/longitude points for novel and known high pH springs sourced in serpentinite outcrops in California. Field work confirms the success of the model, and map output can be merged with published environmental microbiology data (e.g., occurrence of hydrogen-oxidizers) to showcase patterns in microbial community structure. Discrepancies between predicted and actual spring locations are then used to tune GIS suitability analysis, re-running the model with corrected geo-referenced data. This presentation highlights a powerful GIS-based technique for accelerating field exploration in this area of ongoing research.

The significance of "geothermal microzonation" for the correct planning of low-grade source geothermal systems

NASA Astrophysics Data System (ADS)

Viccaro, Marco; Pezzino, Antonino; Belfiore, Giuseppe Maria; Campisano, Carlo

2016-04-01

Despite the environmental-friendly energy systems are solar thermal technologies, photovoltaic and wind power, other advantageous technologies exist, although they have not found wide development in countries such as Italy. Given the almost absent environmental impact and the rather favorable cost/benefit ratio, low-enthalpy geothermal systems are, however, likely to be of strategic importance also in Italy during the next years. The importance of geology for a sustainable exploitation of the ground through geothermal systems from low-grade sources is becoming paramount. Specifically, understanding of the lithological characteristics of the subsurface along with structures and textures of rocks is essential for a correct planning of the probe/geo-exchanger field and their associated ground source heat pumps. The complex geology of Eastern Sicily (Southern Italy), which includes volcanic, sedimentary and metamorphic units over limited extension, poses the question of how thermal conductivity of rocks is variable at the scale of restricted areas (even within the same municipality). This is the innovative concept of geothermal microzonation, i.e., how variable is the geothermal potential as a function of geology at the microscale. Some pilot areas have been therefore chosen to test how the geological features of the subsurface can influence the low-enthalpy geothermal potential of an area. Our geologically based evaluation and micro-zonation of the low-grade source geothermal potential of the selected areas have been verified to be fundamental for optimization of all the main components of a low-enthalpy geothermal system. Saving realization costs and limiting the energy consumption through correct sizing of the system are main ambitions to have sustainable development of this technology with intensive utilization of the subsurface. The variegated territory of countries such as Italy implies that these goals can be only reached if, primarily, the geological features of the shallow subsurface (i.e., chemical-physical characteristics of rocks and fluids of the first 100 m below the ground) are appropriately constrained.

Source-rock geochemistry of the San Joaquin Basin Province, California: Chapter 11 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

USGS Publications Warehouse

Peters, Kenneth E.; Magoon, Leslie B.; Valin, Zenon C.; Lillis, Paul G.

2007-01-01

Source-rock thickness and organic richness are important input parameters required for numerical modeling of the geohistory of petroleum systems. Present-day depth and thickness maps for the upper Miocene Monterey Formation, Eocene Tumey formation of Atwill (1935), Eocene Kreyenhagen Formation, and Cretaceous-Paleocene Moreno Formation source rocks in the San Joaquin Basin were determined using formation tops data from 266 wells. Rock-Eval pyrolysis and total organic carbon data (Rock-Eval/TOC) were collected for 1,505 rock samples from these source rocks in 70 wells. Averages of these data for each well penetration were used to construct contour plots of original total organic carbon (TOCo) and original hydrogen index (HIo) in the source rock prior to thermal maturation resulting from burial. Sufficient data were available to construct plots of TOCo and HIo for all source-rock units except the Tumey formation of Atwill (1935). Thick, organic-rich, oil-prone shales of the upper Miocene Monterey Formation occur in the Tejon depocenter in the southern part of the basin with somewhat less favorable occurrence in the Southern Buttonwillow depocenter to the north. Shales of the upper Miocene Monterey Formation generated most of the petroleum in the San Joaquin Basin. Thick, organic-rich, oil-prone Kreyenhagen Formation source rock occurs in the Buttonwillow depocenters, but it is thin or absent in the Tejon depocenter. Moreno Formation source rock is absent from the Tejon and Southern Buttonwillow depocenters, but thick, organic-rich, oil-prone Moreno Formation source rock occurs northwest of the Northern Buttonwillow depocenter adjacent to the southern edge of Coalinga field.

Bacterial communities associated with subsurface geochemical processes in continental serpentinite springs.

PubMed

Brazelton, William J; Morrill, Penny L; Szponar, Natalie; Schrenk, Matthew O

2013-07-01

Reactions associated with the geochemical process of serpentinization can generate copious quantities of hydrogen and low-molecular-weight organic carbon compounds, which may provide energy and nutrients to sustain subsurface microbial communities independently of the photosynthetically supported surface biosphere. Previous microbial ecology studies have tested this hypothesis in deep sea hydrothermal vents, such as the Lost City hydrothermal field. This study applied similar methods, including molecular fingerprinting and tag sequencing of the 16S rRNA gene, to ultrabasic continental springs emanating from serpentinizing ultramafic rocks. These molecular surveys were linked with geochemical measurements of the fluids in an interdisciplinary approach designed to distinguish potential subsurface organisms from those derived from surface habitats. The betaproteobacterial genus Hydrogenophaga was identified as a likely inhabitant of transition zones where hydrogen-enriched subsurface fluids mix with oxygenated surface water. The Firmicutes genus Erysipelothrix was most strongly correlated with geochemical factors indicative of subsurface fluids and was identified as the most likely inhabitant of a serpentinization-powered subsurface biosphere. Both of these taxa have been identified in multiple hydrogen-enriched subsurface habitats worldwide, and the results of this study contribute to an emerging biogeographic pattern in which Betaproteobacteria occur in near-surface mixing zones and Firmicutes are present in deeper, anoxic subsurface habitats.

Bacterial Communities Associated with Subsurface Geochemical Processes in Continental Serpentinite Springs

PubMed Central

Morrill, Penny L.; Szponar, Natalie; Schrenk, Matthew O.

2013-01-01

Reactions associated with the geochemical process of serpentinization can generate copious quantities of hydrogen and low-molecular-weight organic carbon compounds, which may provide energy and nutrients to sustain subsurface microbial communities independently of the photosynthetically supported surface biosphere. Previous microbial ecology studies have tested this hypothesis in deep sea hydrothermal vents, such as the Lost City hydrothermal field. This study applied similar methods, including molecular fingerprinting and tag sequencing of the 16S rRNA gene, to ultrabasic continental springs emanating from serpentinizing ultramafic rocks. These molecular surveys were linked with geochemical measurements of the fluids in an interdisciplinary approach designed to distinguish potential subsurface organisms from those derived from surface habitats. The betaproteobacterial genus Hydrogenophaga was identified as a likely inhabitant of transition zones where hydrogen-enriched subsurface fluids mix with oxygenated surface water. The Firmicutes genus Erysipelothrix was most strongly correlated with geochemical factors indicative of subsurface fluids and was identified as the most likely inhabitant of a serpentinization-powered subsurface biosphere. Both of these taxa have been identified in multiple hydrogen-enriched subsurface habitats worldwide, and the results of this study contribute to an emerging biogeographic pattern in which Betaproteobacteria occur in near-surface mixing zones and Firmicutes are present in deeper, anoxic subsurface habitats. PMID:23584766

Failure of cap-rock seals as determined from mechanical stratigraphy, stress history, and tensile-failure analysis of exhumed analogs

DOE PAGES

Petrie, E. S.; Evans, J. P.; Bauer, S. J.

2014-11-01

In this study, the sedimentologic and tectonic histories of clastic cap rocks and their inherent mechanical properties control the nature of permeable fractures within them. The migration of fluid through mm- to cm-scale fracture networks can result in focused fluid flow allowing hydrocarbon production from unconventional reservoirs or compromising the seal integrity of fluid traps. To understand the nature and distribution of subsurface fluid-flow pathways through fracture networks in cap-rock seals we examine four exhumed Paleozoic and Mesozoic seal analogs in Utah. We combine these outcrop analyses with subsidence analysis, paleoloading histories, and rock-strength testing data in modified Mohr–Coulomb–Griffith analysesmore » to evaluate the effects of differential stress and rock type on fracture mode.« less

Depositional systems and stratigraphy of Paleozoic and Lower Mesozoic rocks in outcrop, Tassili region, southwest Algeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hertig, S.P.; Tye, R.S.; Coffield, D.Q.

1991-08-01

Paleozoic to Lower Mesozoic strata of the southeastern Algerian Tassili are traditionally subdivided by regionally extensive unconformities such as the Pan African, Taconic, Caledonian, and Hercynian. Using outcrop data from southeastern Algeria, this classic approach is modified by reinterpreting the genesis of these unconformities and rock sequences. Five prominent sequences, defined within the Paleozoic and lower Mesozoic section, usually consist of a succession of lowstand, transgressive, and highstand system tracts separated by sequence boundaries or transgressive surfaces. The Pan-African, Taconic, Caledonian, and Hercynian unconformities are sequence boundaries. Important sequence boundaries also occur within the Ordovician and Silurian sections. These sequencesmore » correlate with subsurface data in the Illizi basin and provide a framework for renewed exploration in the subsurface of the Algerian Sahara, where more than 30 billion bbl of recoverable oil and oil equivalent have been generated and trapped.« less

Multiple sulphur and oxygen isotopes reveal microbial sulphur cycling in spring waters in the Lower Engadin, Switzerland.

PubMed

Strauss, Harald; Chmiel, Hannah; Christ, Andreas; Fugmann, Artur; Hanselmann, Kurt; Kappler, Andreas; Königer, Paul; Lutter, Andreas; Siedenberg, Katharina; Teichert, Barbara M A

2016-01-01

Highly mineralized springs in the Scuol-Tarasp area of the Lower Engadin and in the Albula Valley near Alvaneu, Switzerland, display distinct differences with respect to the source and fate of their dissolved sulphur species. High sulphate concentrations and positive sulphur (δ(34)S) and oxygen (δ(18)O) isotopic compositions argue for the subsurface dissolution of Mesozoic evaporitic sulphate. In contrast, low sulphate concentrations and less positive or even negative δ(34)S and δ(18)O values indicate a substantial contribution of sulphate sulphur from the oxidation of sulphides in the crystalline basement rocks or the Jurassic sedimentary cover rocks. Furthermore, multiple sulphur (δ(34)S, Δ(33)S) isotopes support the identification of microbial sulphate reduction and sulphide oxidation in the subsurface, the latter is also evident through the presence of thick aggregates of sulphide-oxidizing Thiothrix bacteria.

Metagenomic identification of active methanogens and methanotrophs in serpentinite springs of the Voltri Massif, Italy.

PubMed

Brazelton, William J; Thornton, Christopher N; Hyer, Alex; Twing, Katrina I; Longino, August A; Lang, Susan Q; Lilley, Marvin D; Früh-Green, Gretchen L; Schrenk, Matthew O

2017-01-01

The production of hydrogen and methane by geochemical reactions associated with the serpentinization of ultramafic rocks can potentially support subsurface microbial ecosystems independent of the photosynthetic biosphere. Methanogenic and methanotrophic microorganisms are abundant in marine hydrothermal systems heavily influenced by serpentinization, but evidence for methane-cycling archaea and bacteria in continental serpentinite springs has been limited. This report provides metagenomic and experimental evidence for active methanogenesis and methanotrophy by microbial communities in serpentinite springs of the Voltri Massif, Italy. Methanogens belonging to family Methanobacteriaceae and methanotrophic bacteria belonging to family Methylococcaceae were heavily enriched in three ultrabasic springs (pH 12). Metagenomic data also suggest the potential for hydrogen oxidation, hydrogen production, carbon fixation, fermentation, and organic acid metabolism in the ultrabasic springs. The predicted metabolic capabilities are consistent with an active subsurface ecosystem supported by energy and carbon liberated by geochemical reactions within the serpentinite rocks of the Voltri Massif.

Methods of producing transportation fuel

DOEpatents

Nair, Vijay [Katy, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Cherrillo, Ralph Anthony [Houston, TX; Bauldreay, Joanna M [Chester, GB

2011-12-27

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for producing transportation fuel is described herein. The method for producing transportation fuel may include providing formation fluid having a boiling range distribution between -5.degree. C. and 350.degree. C. from a subsurface in situ heat treatment process to a subsurface treatment facility. A liquid stream may be separated from the formation fluid. The separated liquid stream may be hydrotreated and then distilled to produce a distilled stream having a boiling range distribution between 150.degree. C. and 350.degree. C. The distilled liquid stream may be combined with one or more additives to produce transportation fuel.

Method for determining formation quality factor from well log data and its application to seismic reservoir characterization

DOEpatents

Walls, Joel; Taner, M. Turhan; Dvorkin, Jack

2006-08-08

A method for seismic characterization of subsurface Earth formations includes determining at least one of compressional velocity and shear velocity, and determining reservoir parameters of subsurface Earth formations, at least including density, from data obtained from a wellbore penetrating the formations. A quality factor for the subsurface formations is calculated from the velocity, the density and the water saturation. A synthetic seismogram is calculated from the calculated quality factor and from the velocity and density. The synthetic seismogram is compared to a seismic survey made in the vicinity of the wellbore. At least one parameter is adjusted. The synthetic seismogram is recalculated using the adjusted parameter, and the adjusting, recalculating and comparing are repeated until a difference between the synthetic seismogram and the seismic survey falls below a selected threshold.

Characterisation of DOC and its relation to the deep terrestrial biosphere

NASA Astrophysics Data System (ADS)

Vieth, Andrea; Vetter, Alexandra; Sachse, Anke; Horsfield, Brian

2010-05-01

The deep subsurface is populated by a large number of microorganisms playing a pivotal role in the carbon cycling. The question arises as to the origin of the potential carbon sources that support deep microbial communities and their possible interactions within the deep subsurface. As the carbon sources need to be dissolved in formation fluids to become available to microorganisms, the dissolved organic carbon (DOC) needs further characterisation as regards concentration, structural as well as molecular composition and origin. The Malm carbonates in the Molasse basin of southern Germany are of large economic potential as they are targets for both hydrocarbon and geothermal exploration (ANDREWS et al., 1987). Five locations that differ in their depth of the Malm aquifer between 220 m and 3445 m below surface have been selected for fluid sampling. The concentration and the isotopic composition of the DOC have been determined. To get a better insight into the structural composition of the DOC, we also applied size exclusion chromatography and quantified the amount of low molecular weight organic acids (LMWOA) by ion chromatography. With increasing depth of the aquifer the formation fluids show increasing salinity as chloride concentrations increase from 2 to 300 mg/l and also the composition of the DOC changes. Water samples from greater depth (>3000 m) showed that the DOC mainly consists of LMWOA (max. 83 %) and low percentages of neutral compounds (alcohols, aldehyde, ketones, amino acids) as well as "building blocks". Building blocks have been described to be the oxidation intermediates from humic substances to LMWOA. With decreasing depth of the aquifer, the DOC of the fluid becomes increasingly dominated by neutral compounds and the percentage of building blocks increases to around 27%. The fluid sample from 220 m depth still contains a small amount of humic substances. The DOC of formation fluids in some terrestrial sediments may originate from organic-rich layers like coals and source rocks which may provide carbon sources for the deep biosphere by leaching water soluble organic compounds. We investigated the potential of a series of Eocene-Pleistocene coals, mudstones and sandstones from New Zealand with different maturities (Ro between 0.29 and 0.39) and total organic carbon content (TOC) regarding their potential to release such compounds. The water extraction of these New Zealand coals using Soxhlet apparatus resulted in yields of LMWOA that may feed the local deep terrestrial biosphere over geological periods of time (VIETH et al., 2008). However, the DOC of the water extracts mainly consisted of humic substances. To investigate the effect of thermal maturity of the organic matter as well as the effect of the organic matter type on the extraction yields, we examined additional coal samples (Ro between 0.29 and 0.80) and source rock samples from low to medium maturity (Ro between 0.3 to 1.1). Within our presentation we would like to show the compositional diversity and variability of dissolved organic compounds in natural formation fluids as well as in water extracts from a series of very different lithologies and discuss their effects on the carbon cycling in the deep terrestrial subsurface. References: Andrews, J. N., Youngman, M. J., Goldbrunner, J. E., and Darling, W. G., 1987. The geochemistry of formation waters in the Molasse Basin of Upper Austria. Environmental Geology 10, 43-57. Vieth, A., Mangelsdorf, K., Sykes, R., and Horsfield, B., 2008. Water extraction of coals - potential to estimate low molecular weight organic acids as carbon feedstock for the deep terrestrial biosphere? Organic Geochemistry 39, 985-991.

Chemical models for martian weathering profiles: Insights into formation of layered phyllosilicate and sulfate deposits

NASA Astrophysics Data System (ADS)

Zolotov, Mikhail Yu.; Mironenko, Mikhail V.

2016-09-01

Numerical chemical models for water-basalt interaction have been used to constrain the formation of stratified mineralogical sequences of Noachian clay-bearing rocks exposed in the Mawrth Vallis region and in other places on cratered martian highlands. The numerical approaches are based on calculations of water-rock type chemical equilibria and models which include rates of mineral dissolution. Results show that the observed clay-bearing sequences could have formed through downward percolation and neutralization of acidic H2SO4-HCl solutions. A formation of weathering profiles by slightly acidic fluids equilibrated with current atmospheric CO2 requires large volumes of water and is inconsistent with observations. Weathering by solutions equilibrated with putative dense CO2 atmospheres leads to consumption of CO2 to abundant carbonates which are not observed in clay stratigraphies. Weathering by H2SO4-HCl solutions leads to formation of amorphous silica, Al-rich clays, ferric oxides/oxyhydroxides, and minor titanium oxide and alunite at the top of weathering profiles. Mg-Fe phyllosilicates, Ca sulfates, zeolites, and minor carbonates precipitate from neutral and alkaline solutions at depth. Acidic weathering causes leaching of Na, Mg, and Ca from upper layers and accumulation of Mg-Na-Ca sulfate-chloride solutions at depth. Neutral MgSO4 type solutions dominate in middle parts of weathering profiles and could occur in deeper layers owing to incomplete alteration of Ca minerals and a limited trapping of Ca to sulfates. Although salts are not abundant in the Noachian geological formations, the results suggest the formation of Noachian salty solutions and their accumulation at depth. A partial freezing and migration of alteration solutions could have separated sulfate-rich compositions from low-temperature chloride brines and contributed to the observed diversity of salt deposits. A Hesperian remobilization and release of subsurface MgSO4 type solutions into newly-formed depressions could account for formation of some massive layered sulfate deposits through freezing or evaporation. This scenario explains the observed deficiency of salts in Noachian formations, a paucity of Hesperian phyllosilicates, and the occurrence of sulfate deposits in Valles Marineris troughs, chaotic terrains, and some craters of the Hesperian age.

Nonlinear dynamics in flow through unsaturated fractured-porous media: Status and perspectives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faybishenko, Boris

2002-11-27

The need has long been recognized to improve predictions of flow and transport in partially saturated heterogeneous soils and fractured rock of the vadose zone for many practical applications, such as remediation of contaminated sites, nuclear waste disposal in geological formations, and climate predictions. Until recently, flow and transport processes in heterogeneous subsurface media with oscillating irregularities were assumed to be random and were not analyzed using methods of nonlinear dynamics. The goals of this paper are to review the theoretical concepts, present the results, and provide perspectives on investigations of flow and transport in unsaturated heterogeneous soils and fracturedmore » rock, using the methods of nonlinear dynamics and deterministic chaos. The results of laboratory and field investigations indicate that the nonlinear dynamics of flow and transport processes in unsaturated soils and fractured rocks arise from the dynamic feedback and competition between various nonlinear physical processes along with complex geometry of flow paths. Although direct measurements of variables characterizing the individual flow processes are not technically feasible, their cumulative effect can be characterized by analyzing time series data using the models and methods of nonlinear dynamics and chaos. Identifying flow through soil or rock as a nonlinear dynamical system is important for developing appropriate short- and long-time predictive models, evaluating prediction uncertainty, assessing the spatial distribution of flow characteristics from time series data, and improving chemical transport simulations. Inferring the nature of flow processes through the methods of nonlinear dynamics could become widely used in different areas of the earth sciences.« less

Oil/water/rock wettability: Influencing factors and implications for low salinity water flooding in carbonate reservoirs

DOE PAGES

Chen, Yongqiang; Xie, Quan; Sari, Ahmad; ...

2017-11-21

Wettability of the oil/brine/rock system is an essential petro-physical parameter which governs subsurface multiphase flow behaviour and the distribution of fluids, thus directly affecting oil recovery. Recent studies [1–3] show that manipulation of injected brine composition can enhance oil recovery by shifting wettability from oil-wet to water-wet. However, what factor(s) control system wettability has not been completely elucidated due to incomplete understanding of the geochemical system. To isolate and identify the key factors at play we used in this paper SO 4 2—free solutions to examine the effect of salinity (formation brine/FB, 10 times diluted formation brine/10 dFB, and 100more » times diluted formation brine/100 dFB) on the contact angle of oil droplets at the surface of calcite. We then compared contact angle results with predictions of surface complexation by low salinity water using PHREEQC software. We demonstrate that the conventional dilution approach likely triggers an oil-wet system at low pH, which may explain why the low salinity water EOR-effect is not always observed by injecting low salinity water in carbonated reservoirs. pH plays a fundamental role in the surface chemistry of oil/brine interfaces, and wettability. Our contact angle results show that formation brine triggered a strong water-wet system (35°) at pH 2.55, yet 100 times diluted formation brine led to a strongly oil-wet system (contact angle = 175°) at pH 5.68. Surface complexation modelling correctly predicted the wettability trend with salinity; the bond product sum ([>CaOH 2 +][–COO -] + [>CO 3 -][–NH +] + [>CO 3 -][–COOCa +]) increased with decreasing salinity. Finally, at pH < 6 dilution likely makes the calcite surface oil-wet, particularly for crude oils with high base number. Yet, dilution probably causes water wetness at pH > 7 for crude oils with high acid number.« less

Oil/water/rock wettability: Influencing factors and implications for low salinity water flooding in carbonate reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Yongqiang; Xie, Quan; Sari, Ahmad

Wettability of the oil/brine/rock system is an essential petro-physical parameter which governs subsurface multiphase flow behaviour and the distribution of fluids, thus directly affecting oil recovery. Recent studies [1–3] show that manipulation of injected brine composition can enhance oil recovery by shifting wettability from oil-wet to water-wet. However, what factor(s) control system wettability has not been completely elucidated due to incomplete understanding of the geochemical system. To isolate and identify the key factors at play we used in this paper SO 4 2—free solutions to examine the effect of salinity (formation brine/FB, 10 times diluted formation brine/10 dFB, and 100more » times diluted formation brine/100 dFB) on the contact angle of oil droplets at the surface of calcite. We then compared contact angle results with predictions of surface complexation by low salinity water using PHREEQC software. We demonstrate that the conventional dilution approach likely triggers an oil-wet system at low pH, which may explain why the low salinity water EOR-effect is not always observed by injecting low salinity water in carbonated reservoirs. pH plays a fundamental role in the surface chemistry of oil/brine interfaces, and wettability. Our contact angle results show that formation brine triggered a strong water-wet system (35°) at pH 2.55, yet 100 times diluted formation brine led to a strongly oil-wet system (contact angle = 175°) at pH 5.68. Surface complexation modelling correctly predicted the wettability trend with salinity; the bond product sum ([>CaOH 2 +][–COO -] + [>CO 3 -][–NH +] + [>CO 3 -][–COOCa +]) increased with decreasing salinity. Finally, at pH < 6 dilution likely makes the calcite surface oil-wet, particularly for crude oils with high base number. Yet, dilution probably causes water wetness at pH > 7 for crude oils with high acid number.« less

Thermal history of rocks in southern San Joaquin Valley, California: evidence from fission-track analysis

USGS Publications Warehouse

Naeser, N.D.; Naeser, C.W.; McCulloh, T.H.

1990-01-01

Fission-track analysis has been used to study the thermal and depositional history of the subsurface Tertiary sedimentary rocks on both sides of the active White Wolf reverse fault in the southern San Joaquin Valley. The distinctly different thermal histories of the rocks in the two structural blocks are clearly reflected in the apatite fission-track data, which suggest that rocks in the rapidly subsiding basin northwest of the fault have been near their present temperature for only about 1 m.y. compared with about 10 m.y. for rocks southeast of the fault. These estimates of heating time agree with previous estimates for these rocks. Zircon fission-track data indicate that the Tertiary sediments were derived from parent rocks of more than one age. However, from at least the Eocene to late Miocene or Pliocene, the major sediment source was rocks related to the youngest Sierra Nevada Mesozoic intrusive complexes, which are presently exposed east and south of the southern San Joaquin Valley. -from Authors

Compilation of Stratigraphic Thicknesses for Caldera-Related Tertiary Volcanic Rocks, East-Central Nevada and West-Central Utah

USGS Publications Warehouse

Sweetkind, D.S.; Du Bray, E.A.

2008-01-01

The U.S. Geological Survey (USGS), the Desert Research Institute (DRI), and a designee from the State of Utah are currently conducting a water-resources study of aquifers in White Pine County, Nevada, and adjacent areas in Nevada and Utah, in response to concerns about water availability and limited geohydrologic information relevant to ground-water flow in the region. Production of ground water in this region could impact water accumulations in three general types of aquifer materials: consolidated Paleozoic carbonate bedrock, and basin-filling Cenozoic volcanic rocks and unconsolidated Quaternary sediments. At present, the full impact of extracting ground water from any or all of these potential valley-graben reservoirs is not fully understood. A thorough understanding of intermontane basin stratigraphy, mostly concealed by the youngest unconsolidated deposits that blanket the surface in these valleys, is critical to an understanding of the regional hydrology in this area. This report presents a literature-based compilation of geologic data, especially thicknesses and lithologic characteristics, for Tertiary volcanic rocks that are presumably present in the subsurface of the intermontane valleys, which are prominent features of this area. Two methods are used to estimate volcanic-rock thickness beneath valleys: (1) published geologic maps and accompanying descriptions of map units were used to compile the aggregate thicknesses of Tertiary stratigraphic units present in each mountain range within the study areas, and then interpolated to infer volcanic-rock thickness in the intervening valley, and (2) published isopach maps for individual out-flow ash-flow tuff were converted to digital spatial data and thickness was added together to produce a regional thickness map that aggregates thickness of the individual units. The two methods yield generally similar results and are similar to volcanic-rock thickness observed in a limited number of oil and gas exploration drill holes in the region, although local geologic complexity and the inherent assumptions in both methods allow only general comparison. These methods serve the needs of regional ground-water studies that require a three-dimensional depiction of the extent and thickness of subsurface geologic units. The compilation of geologic data from published maps and reports provides a general understanding of the distribution and thickness of tuffs that are presumably present in the subsurface of the intermontane valleys and are critical to understanding the ground-water hydrology of this area.

Subsurface structure imaging of the Sembalun-Propok area, West Nusa Tenggara, Indonesia by using the audio-frequency magnetotelluric data

NASA Astrophysics Data System (ADS)

Febriani, F.; Widarto, D. S.; Gaffar, E.; Nasution, A.; Grandis, H.

2017-07-01

We have investigated the subsurface structure of the Sembalun-Propok Area, West Nusa Tenggara, by using the audio-frequency magnetotelluric (AMT) method. This area is one of the geothermal prospect areas in eastern Indonesia. There are 38 AMT observation points, which were deployed along three profiles. We applied the phase tensor analysis on all observation points to determine both the dimensionality of and the regional strike of the study area. The results of the phase tensor analysis show that the study area can be assumed as 2-D and the regional strike of the study area is about N330°E. Then, after rotating the impedance tensor data to the regional strike, we carried out the 2-D inversion modeling to know more detail the subsurface structure of the study area. The results of the 2-D MT inversion are consistent with the geology of the study area. The near surface along all profiles is dominated by the higher resistivity layer (> 500 Ωm). It is highly associated with the surface geology of the study area which is characterized by the volcanic rock and mostly consist of andesitic to dacitic rocks of a calc-alkaline suite. Below the resistive layer at the near surface, the modelings show the layer which has the lower-moderate resistivity layer. It is possibly a cap rock layer of geothermal system of the Sembalun-Propok area. Lastly, the third layer is the very conductive layer and possibly associated with the presence of thermal fluids in the study area.

Modeling the effects of structure on seismic anisotropy in the Chester gneiss dome, southeast Vermont

NASA Astrophysics Data System (ADS)

Saif, S.; Brownlee, S. J.

2017-12-01

Compositional and structural heterogeneity in the continental crust are factors that contribute to the complex expression of crustal seismic anisotropy. Understanding deformation and flow in the crust using seismic anisotropy has thus proven difficult. Seismic anisotropy is affected by rock microstructure and mineralogy, and a number of studies have begun to characterize the full elastic tensors of crustal rocks in an attempt to increase our understanding of these intrinsic factors. However, there is still a large gap in length-scale between laboratory characterization on the scale of centimeters and seismic wavelengths on the order of kilometers. To address this length-scale gap we are developing a 3D crustal model that will help us determine the effects of rotating laboratory-scale elastic tensors into field-scale structures. The Chester gneiss dome in southeast Vermont is our primary focus. The model combines over 2000 structural data points from field measurements and published USGS structural data with elastic tensors of Chester dome rocks derived from electron backscatter diffraction data. We created a uniformly spaced grid by averaging structural measurements together in equally spaced grid boxes. The surface measurements are then projected into the third dimension using existing subsurface interpretations. A measured elastic tensor for the specific rock type is rotated according to its unique structural input at each point in the model. The goal is to use this model to generate artificial seismograms using existing numerical wave propagation codes. Once completed, the model input can be varied to examine the effects of different subsurface structure interpretations, as well as heterogeneity in rock composition and elastic tensors. Our goal is to be able to make predictions for how specific structures will appear in seismic data, and how that appearance changes with variations in rock composition.

Geophysical delineation of Mg-rich ultramafic rocks for mineral carbon sequestration

USGS Publications Warehouse

McCafferty, Anne E.; Van Gosen, Bradley S.; Krevor, Sam C.; Graves, Chris R.

2009-01-01

This presentation covers three general topics: (1) description of a new geologic compilation of the United States that shows the location of magnesium-rich ultramafic rocks in the conterminous United States; (2) conceptual illustration of the potential ways that ultramafic rocks could be used to sequester carbon dioxide; and (3) description of ways to use geophysical data to refine and extend the geologic mapping of ultramafic rocks and to better characterize their mineralogy.The geophysical focus of this research is twofold. First, we illustrate how airborne magnetic data can be used to map the shallow subsurface geometry of ultramafic rocks for the purpose of estimating the volume of rock material available for mineral CO2 sequestration. Secondly, we explore, on a regional to outcrop scale, how magnetic mineralogy, as expressed in magnetic anomalies, may vary with magnesium minerals, which are the primary minerals of interest for CO2 sequestration. 

Pumice in the interglacial Whidbey Formation at Blowers Bluff, central Whidbey Island, WA, USA

USGS Publications Warehouse

Dethier, D.P.; Dragovich, J.D.; Sarna-Wojcicki, A. M.; Fleck, R.J.

2008-01-01

A new 40Ar/39Ar age of 128??9 ka and chemical analyses of pumice layers from interglacial alluvium at Blowers Bluff, Whidbey Island, WA, show that the deposits are part of the Whidbey Formation, a widespread, mainly subsurface unit. Glass chemistry of the dated dacitic pumice does not match any analyzed northern Cascade source, but upper Pleistocene dacites from Glacier Peak and early Pleistocene silicic rocks from the Kulshan caldera are chemically similar. The chemistry of pumiceous dacite in younger units, including the latest Pleistocene Partridge Gravel, is similar to that of the dated material. The deep troughs of the modern northern Puget lowland must have been filled during deposition of the Whidbey Formation, allowing volcanic-rich sediment to reach what is now Whidbey Island. Topographic analysis of LIDAR images demonstrates that extensive erosion occurred during latest Pleistocene ice retreat. The Partridge Gravel likely records subglacial fluvial erosion along an ice tunnel and ice-marginal deposition into adjacent marine waters. Pumice in the Partridge Gravel probably was reworked from stratigraphically and topographically lower deposits, including those at Blowers Bluff. ?? 2007 Elsevier Ltd and INQUA.

Subsurface deposition of Cu-rich massive sulphide underneath a Palaeoproterozoic seafloor hydrothermal system—the Red Bore prospect, Western Australia

NASA Astrophysics Data System (ADS)

Agangi, Andrea; Reddy, S. M.; Plavsa, D.; Vieru, C.; Selvaraja, V.; LaFlamme, C.; Jeon, H.; Martin, L.; Nozaki, T.; Takaya, Y.; Suzuki, K.

2018-02-01

The Proterozoic Bryah and Yerrida basins of Western Australia contain important base and precious metal deposits. Here we present microtextural data, trace element and S isotope analyses of massive sulphide mineralisation hosted in Palaeoproterozoic subvolcanic rocks (dolerite) recently discovered at Red Bore. The small-scale high-grade mineralisation, which extends from the sub-surface to at least 95 m down-hole, is dominated by massive chalcopyrite and contains minor pyrite and Bi-Te-(Se) phases. Massive sulphide mineralisation is surrounded by discontinuous brecciated massive magnetite, and a narrow (< 2 m) alteration halo, which suggests very focussed fluid flow. Laser ablation ICP-MS analyses indicate that chalcopyrite contains up to 10 ppm Au and in excess of 100 ppm Ag. Sulphur isotope analyses of pyrite and chalcopyrite indicate a narrow range of δ34SVCD (- 0.2 to + 4.6 ‰), and no significant mass-independent fractionation (- 0.1 < Δ33S < + 0.05 ‰). Re-Os isotope analyses yield scattered values, which suggests secondary remobilisation. Despite the geographical proximity and the common Cu-Au-Ag association, the mineralisation at Red Bore has significant differences with massive sulphide mineralisation at neighbouring DeGrussa, as well as other massive sulphide deposits around the world. These differences include the geometry, sub-volcanic host rocks, extreme Cu enrichment and narrow δ34S ranges. Although a possible explanation for some of these characteristics is leaching of S and metals from the surrounding volcanic rocks, we favour formation as a result of the release of a magmatic fluid phase along very focussed pathways, and we propose that mixing of this fluid with circulating sea water contributed to sea floor mineralisation similar to neighbouring VHMS deposits. Our data are permissive of a genetic association of Red Bore mineralisation with VHMS deposits nearby, thus suggesting a direct connection between magmatism and mineralising fluids responsible for VHMS deposition at surface. Therefore, the Red Bore mineralisation may represent the magmatic roots of a VHMS system.

Influence of Natural Fractures Cohesive Properties on Geometry of Hydraulic Fracture Networks

NASA Astrophysics Data System (ADS)

Gonzalez-Chavez, M. A.; Dahi Taleghani, A.; Puyang, P.

2014-12-01

An integrated modeling methodology is proposed to analyze hydraulic fracturing jobs in the presence of the natural fracture network in the formation. A propagating hydraulic fracture may arrest, cross, or diverts into a preexisting natural crack depending on fracture properties of rock and magnitude and direction of principal rock stresses. Opening of natural fractures during fracturing treatment could define the effectiveness of the stimulation technique. Here, we present an integrated methodology initiated with lab scale fracturing properties using Double Cantilever Beam tests (DCB) to determine cohesive properties of rock and natural fractures. We used cohesive finite element models to reproduce laboratory results to verify the numerical model for the interaction of the hydraulic fracture and individual cemented natural fractures. Based on the initial investigations, we found out that distribution of pre-existing natural fractures could play a significant role in the final geometry of the induced fracture network; however in practice, there is not much information about the distribution of natural fractures in the subsurface due to the limited access. Hence, we propose a special optimization scheme to generate natural fracture geometry from the location of microseismic events. Accordingly, the criteria of evaluating the fitness of natural fracture realizations is defined as the total minimum distance squares of all microseismic events, which is the sum of minimum square distance for all microseismic events. Moreover, an additional constraint in this problem is that we need to set a minimum distance between fracture grids. Using generated natural fracture realizations, forward field-scale simulations are implemented using cohesive finite element analysis to find the best match with the recorded bottomhole pressure. To show the robustness of the proposed workflow for real field problem, we implemented this technique on available data from several well Chicontepec basin to forecast post-treatment production rate. Our results show a constructive approach to integrate microseismic maps with lab mechanical measurements and bottomhole pressure to estimate the geometry of induced fracture network in the subsurface which does not suffer from any limiting assumption about fracture geometries.

Magnetic and gravity studies of Mono Lake, east-central, California

USGS Publications Warehouse

Athens, Noah D.; Ponce, David A.; Jayko, Angela S.; Miller, Matt; McEvoy, Bobby; Marcaida, Mae; Mangan, Margaret T.; Wilkinson, Stuart K.; McClain, James S.; Chuchel, Bruce A.; Denton, Kevin M.

2014-01-01

From August 26 to September 5, 2011, the U.S. Geological Survey (USGS) collected more than 600 line-kilometers of shipborne magnetic data on Mono Lake, 20 line-kilometers of ground magnetic data on Paoha Island, 50 gravity stations on Paoha and Negit Islands, and 28 rock samples on Paoha and Negit Islands, in east-central California. Magnetic and gravity investigations were undertaken in Mono Lake to study regional crustal structures and to aid in understanding the geologic framework, in particular regarding potential geothermal resources and volcanic hazards throughout Mono Basin. Furthermore, shipborne magnetic data illuminate local structures in the upper crust beneath Mono Lake where geologic exposure is absent. Magnetic and gravity methods, which sense contrasting physical properties of the subsurface, are ideal for studying Mono Lake. Exposed rock units surrounding Mono Lake consist mainly of Quaternary alluvium, lacustrine sediment, aeolian deposits, basalt, and Paleozoic granitic and metasedimentary rocks (Bailey, 1989). At Black Point, on the northwest shore of Mono Lake, there is a mafic cinder cone that was produced by a subaqueous eruption around 13.3 ka. Within Mono Lake there are several small dacite cinder cones and flows, forming Negit Island and part of Paoha Island, which also host deposits of Quaternary lacustrine sediments. The typical density and magnetic properties of young volcanic rocks contrast with those of the lacustrine sediment, enabling us to map their subsurface extent.

Exploration geothermal gradient drilling, Platanares, Honduras, Central America

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goff, S.J.; Laughlin, A.W.; Ruefenacht, H.D.

1988-01-01

This paper is a review and summary of the core drilling operations component of the Honduras Geothermal Resource Development Project at the Platanares geothermal prospect in Honduras, Central America. Three intermediate depth (428 to 679 m) coreholes are the first continuously cored geothermal exploration boreholes in Honduras. These coring operations are part of the Central America Energy Resource Project (CAERP) effort funded by the Agency for International Development (AID) and implemented by the Los Alamos National Laboratory (Los Alamos) in cooperation with the Empresa Nacional de Energia Electrica (ENEE) and the United States Geological Survey (USGS). This report emphasizes coringmore » operations with reference to the stratigraphy, thermal gradient, and flow test data of the boreholes. The primary objectives of this coring effort were (1) to obtain quantitative information on the temperature distribution as a function of depth, (2) to recover fluids associated with the geothermal reservoir, (3) to recover 75% or better core from the subsurface rock units, and (4) to drill into the subsurface rock as deeply as possible in order to get information on potential reservoir rocks, fracture density, permeabilities, and alteration histories of the rock units beneath the site. The three exploration coreholes drilled to depths of 650, 428 and 679 m, respectively, encountered several hot water entries. Coring operations and associated testing began in mid-October 1986 and were completed at the end of June 1987.« less

New type of kinematic indicator in bed-parallel veins, Late Jurassic-Early Cretaceous Vaca Muerta Formation, Argentina: E-W shortening during Late Cretaceous vein opening

NASA Astrophysics Data System (ADS)

Ukar, Estibalitz; Lopez, Ramiro G.; Gale, Julia F. W.; Laubach, Stephen E.; Manceda, Rene

2017-11-01

In the Late Jurassic-Early Cretaceous Vaca Muerta Formation, previously unrecognized yet abundant structures constituting a new category of kinematic indicator occur within bed-parallel fibrous calcite veins (BPVs) in shale. Domal shapes result from localized shortening and thickening of BPVs and the intercalation of centimeter-thick, host-rock shale inclusions within fibrous calcite beef, forming thrust fault-bounded pop-up structures. Ellipsoidal and rounded structures show consistent orientations, lineaments of interlayered shale and fibrous calcite, and local centimeter-scale offset thrust faults that at least in some cases cut across the median line of the BPV and indicate E-W shortening. Continuity of crystal fibers shows the domal structures are contemporaneous with BPV formation and help establish timing of fibrous vein growth in the Late Cretaceous, when shortening directions were oriented E-W. Differences in the number of opening stages and the deformational style of the different BPVs indicate they may have opened at different times. The new domal kinematic indicators described in this study are small enough to be captured in core. When present in the subsurface, domal structures can be used to either infer paleostress orientation during the formation of BPVs or to orient core in cases where the paleostress is independently known.

The Role of Alpine Wetlands as Hot Spots of Dissolved Organic Carbon Fluxes in the East River, Colorado

NASA Astrophysics Data System (ADS)

Winnick, M.; Rainaldi, G. R.; Lawrence, C. R.; McCormick, M. E.; Hsu, H. T.; Druhan, J. L.; Williams, K. H.; Maher, K.

2016-12-01

Dissolved organic carbon (DOC) is a critical chemical attribute of freshwater systems, affecting nutrient availability, toxicity and solubility of metals, and biological activity via the absorption of light and microbial consumption of O2 during DOC mineralization. Although DOC contributions to streams are distributed across the landscape in the shallow subsurface, many studies have demonstrated area-outsized contributions from riparian zones with high biological productivity and low subsurface O2 concentrations. In the East River, CO, a high-elevation watershed located in the central Rocky Mountains, initial observations show that DOC concentrations of two tributaries, Rock Creek and Gothic Creek, are elevated by 3-10 times compared to concentrations in the main East River and its other tributaries. These elevated concentrations are qualitatively linked to the unique presence of large wetlands in the headwaters of Rock and Gothic creeks, which due to potential anoxic conditions, experience reduced rates of organic matter decomposition and serve as an elevated source of DOC. In this study we quantify the cycling of organic matter in these alpine wetlands and their area-outsized contributions to East River DOC fluxes. We present concentration profiles of DOC along stream reaches and along subsurface flowpaths that span the transition from hillslope to wetland coupled with high-resolution mapping of chronically-saturated zones and calculate area-weighted fluxes of DOC from wetlands to Rock and Gothic creeks at multiple times through the 2016 growing season. Additionally, soil and groundwater DOC fluxes are compared with depth-resolved organic carbon content from soil cores, substrate quality (C:N), and soil surface CO2 fluxes to evaluate organic carbon budgets in the hillslope and wetland areas feeding Rock Creek. The characterization of these hotspots of DOC generation and transport in the East River is vital to the ability to predict nutrient cycling changes into the future.

Seismic model study of Patrick Draw field, Wyoming: a stratigraphic trap in the Upper Cretaceous Almond Formation

USGS Publications Warehouse

Anderson, Robert C.; Ryder, Robert T.

1978-01-01

The Patrick Draw field, located on the eastern flank of the Rock Springs uplift in the Washakie basin of southwestern Wyoming, was discovered in 1959 without the use of geophysical methods. The field is a classic example of a stratigraphic trap, where Upper Cretaceous porous sandstone units pinch out on a structural nose. Two-dimensional seismic modeling was used to construct the seismic waveform expressions of the Patrick Draw field, and to better understand how to explore for other 'Patrick Draw' fields. Interpretation of the model shows that the detection of the reservoir sand is very difficult, owing to a combination of acoustic contrasts and bed thickness. Because the model included other major stratigraphic units in the subsurface, several stratigraphic traps are suggested as potential exploration targets.

Geophysical interpretations west of and within the northwestern part of the Nevada Test Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grauch, V.J.; Sawyer, D.A.; Fridrich, C.J.

1997-12-31

This report focuses on interpretation of gravity and new magnetic data west of the Nevada Test Site (NTS) and within the northwestern part of NTS. The interpretations integrate the gravity and magnetic data with other geophysical, geological, and rock property data to put constraints on tectonic and magmatic features not exposed at the surface. West of NTS, where drill hole information is absent, these geophysical data provide the best available information on the subsurface. Interpreted subsurface features include calderas, intrusions, basalt flows and volcanoes, Tertiary basins, structurally high pre-Tertiary rocks, and fault zones. New features revealed by this study includemore » (1) a north-south buried tectonic fault east of Oasis Mountain, which the authors call the Hogback fault; (2) an east striking fault or accommodation zone along the south side of Oasis Valley basin, which they call the Hot Springs fault; (3) a NNE striking structural zone coinciding with the western margins of the caldera complexes; (4) regional magnetic highs that probably represent a thick sequence of Tertiary volcanic rocks; and (5) two probable buried calderas that may be related to the tuffs of Tolicha Peak and of Sleeping Butte, respectively.« less

Subsurface Structure Determination of Geotermal Area in Siogung-ogung Samosir District by Using Magnetic Method

NASA Astrophysics Data System (ADS)

Tampubolon, Togi; Hutahaean, Juniar; Siregar, Suryani N. J.

2018-03-01

Underwater research often uses geomagnets. It is one of the geophysical methods for measuring magnetic field variations. This research was done to identify how the subsurface rock structure is and determine kinds of rock based on its susceptibility value in Siogung-ogung geothermal area, Pangururan, Samosir District. The tool measurement of total magnetic field called Proton Precission Magnetometer, positioning using Global Position System, and north axis determination using geological compass. Data collection was done randomly with total 51 measuring points obtained. Data analysis started with International geomagnetics Reference Field correction to obtain the total magnetic field anomaly. Then, the data analysis of total magnetic anomaly was done by using surfer program 12. To get a magnetic anomaly cross section used Magdc For Windows program. Magnetic measurement results indicated that the variation of magnetic field strength in each point with the lowest magnetic intensity value of 41785.67 nano tesla. The highest magnetic intensity value is 43140, 33. From the results of qualitative interpretation, the magnetic anomaly value is at -200.92 to 1154.45 whereas the quantitative interpretive results of model show the existence of degradation and andesitic rocks, with the value of susceptibility

Washington Geothermal Play Fairway Analysis Data From Potential Field Studies

DOE Data Explorer

Anderson, Megan; Ritzinger, Brent; Glen, Jonathan; Schermerhorn, William

2017-12-20

A recent study which adapts play fairway analysis (PFA) methodology to assess geothermal potential was conducted at three locations (Mount Baker, Mount St. Helens seismic zone, and Wind River valley) along the Washington Cascade Range (Forson et al. 2017). Potential field (gravity and magnetic) methods which can detect subsurface contrasts in physical properties, provides a means for mapping and modeling subsurface geology and structure. As part of the WA-Cascade PFA project, we performed potential field studies by collecting high-resolution gravity and ground-magnetic data, and rock property measurements to (1) identify and constrain fault geometries (2) constrain subsurface lithologic distribution (3) study fault interactions (4) identify areas favorable to hydrothermal flow, and ultimately (5) guide future geothermal exploration at each location.

Analysis of continuous multi-seasonal in-situ subsurface temperature measurements on Mars

NASA Astrophysics Data System (ADS)

Paton, M. D.; Harri, A.-M.; Mäkinen, T.; Savijärvi, H.; Kemppinen, O.; Hagermann, A.

2015-10-01

Our investigations reveal the local thermal properties on the Martian surface at the Viking Lander 1 (VL-1) site. We achieved this by using the VL-1 footpad temperature sensor which was buried, and due to its location, was under shadow for extensive periods of time during each sol. Reconstruction of the surface and subsurface temperature history of the regolith in the vicinity of the temperature sensor was made using a 1-D atmospheric column model (UH-FMI) together with a thermal model of the lander. The results have implications for the interpretation of subsurface thermal measurements made close to a spacecraft or rock, interpretation of remote sensing measurements of thermal inertia and understanding the micro-scale behavior of the Martian atmosphere.

Geophysical framework of the southwestern Nevada volcanic field and hydrogeologic implications

USGS Publications Warehouse

Grauch, V.J.; Sawyer, David A.; Fridrich, Chris J.; Hudson, Mark R.

1999-01-01

Gravity and magnetic data, when integrated with other geophysical, geological, and rock-property data, provide a regional framework to view the subsurface geology in the southwestern Nevada volcanic field. The region has been loosely divided into six domains based on structural style and overall geophysical character. For each domain, the subsurface tectonic and magmatic features that have been inferred or interpreted from previous geophysical work has been reviewed. Where possible, abrupt changes in geophysical fields as evidence for potential structural lithologic control on ground-water flow has been noted. Inferred lithology is used to suggest associated hydrogeologic units in the subsurface. The resulting framework provides a basis for investigators to develop hypotheses from regional ground-water pathways where no drill-hole information exists.

Review of the general geology and solid-phase geochemical studies in the vicinity of the Central Oklahoma aquifer

USGS Publications Warehouse

Mosier, Elwin L.; Bullock, John H.

1988-01-01

The Central Oklahoma aquifer is the principal source of ground water for municipal, industrial, and rural use in central Oklahoma. Ground water in the aquifer is contained in consolidated sedimentary rocks consisting of the Admire, Council Grove, and Chase Groups, Wellington Formation, and Garber Sandstone and in the unconsolidated Quaternary alluvium and terrace deposits that occur along the major stream systems in the study area. The Garber Sandstone and the Wellington Formation comprise the main flow system and, as such, the aquifer is often referred to as the 'Garber-Wellington aquifer.' The consolidated sedimentary rocks consist of interbedded lenticular sandstone, shale, and siltstone beds deposited in similar deltaic environments in early Permian time. Arsenic, chromium, and selenium are found in the ground water of the Central Oklahoma aquifer in concentrations that, in places, exceed the primary drinking-water standards of the Environmental Protection Agency. Gross-alpha concentrations also exceed the primary standards in some wells, and uranium concentrations are uncommonly high in places. As a prerequisite to a surface and subsurface solid-phase geochemical study, this report summarizes the general geology of the Central Oklahoma study area. Summaries of results from certain previously reported solid-phase geochemical studies that relate to the vicinity of the Central Oklahoma aquifer are also given; including a summary of the analytical results and distribution plots for arsenic, selenium, chromium, thorium, uranium, copper, and barium from the U.S. Department of Energy's National Uranium Resource Evaluation (NURE) Program.

Alpha Recoil Flux of Radon in Groundwater and its Experimental Measurement

NASA Astrophysics Data System (ADS)

Mehta, N.; Harvey, C. F.; Kocar, B. D.

2016-12-01

Groundwater Radon (Rn222) activity is primarily controlled by alpha recoil process (radioactive decay), however, evaluating the rate and extent of this process, and its impact on porewater radioactivity, remains uncertain. Numerous factors contribute to this uncertainty, including the spatial distribution of parent radionuclides (e.g. U238, Th232 , Ra226 and Ra228) within native materials, differences in nuclide recoil length in host matrix and the physical structure of the rock strata (pore size distribution and porosity). Here, we experimentally measure Radon activities within porewater contributed through alpha recoil, and analyze its variations as a function of pore structure and parent nuclide distribution within host matrices, including Marcellus shale rock and Serrie-Copper Pegmatite. The shale cores originate from the Marcellus formation in Mckean, Pennsylvania collected at depths ranging from 1000-7000 feet, and the U-Th-rich Pegmatite is obtained from South Platte District, Colorado. Columns are packed with granulated rock of varying surface area (30,000-60,000 cm2/g) and subjected to low salinity sodium chloride solution in a close loop configuration. The activity of Radon (Rn222) and radium (Ra226) in the saline fluid is measured over time to determine recoil supply rates. Mineralogical and trace element data for rock specimens are characterized using XRD and XRF, and detailed geochemical profiles are constructed through total dissolution and analysis using ICP-MS and ICP-OES. Naturally occurring Radium nuclides and its daughters are quantified using a low-energy Germanium detector. The parent nuclide (U238 and Th232) distribution in the host rock is studied using X-Ray Absorption Spectroscopy (XAS). Our study elucidates the contribution of alpha recoil on the appearance and distribution of Radon (Rn222) within porewater of representative rock matrices. Further, we illustrate the effects of chemical and physical heterogeneity on the rate of this process, which may inform models predicting the fate and transport of radionuclides in subsurface environments.

The evolution of cave systems from the surface to subsurface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loucks, R.G.; Handford, C.R.

1996-01-01

Many carbonate reservoirs are the result of cave-forming processes. The origin and recognition of fractures, breccias, and sediment fills associated with paleocaves were determined through the study of modern and paleocaves systems. Cave formation and destruction are the products of near-surface processes. Near-surface processes include solutional excavation, clastic and chemical sedimentation, and collapse of cave walls and ceilings. Cave sediment is derived from inside and/or outside the system. Depositional mechanisms include suspension, tractional, mass-flow and rock-fall. Collapse of ceilings and walls from chaotic breakdown breccias. These piles can be tens of meters thick and contain large voids and variable amountsmore » of matrix. Cave-roof crackle breccia forms from stress-and tension-related fractures in cave-roof strata. As the cave-bearing strata subside into the subsurface, mechanical compaction increases and restructures the existing breccias and remaining cavities. Fracture porosity increases and breccia and vug porosity decreases. Large cavities collapse forming burial chaotic breakdown breccias. Differentially compacted strata over the collapsed chamber fracture and form burial cave-roof crackle breccias. Continued burial leads to more extensive mechanical compaction causing previously formed clasts to fracture and pack closer together. The resulting product is a rebrecciated chaotic breakdown breccia composed predominantly of small clasts. Rebrecciated blocks are often overprinted by crackling. Subsurface paleocave systems commonly have a complex history with several episodes of fracturing and brecciation. The resulting collapsed-paleocave reservoir targets are not single collapsed passages of tens of feet across, but are homogenized collapsed-cave systems hundreds to several thousand feet across.« less

The evolution of cave systems from the surface to subsurface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loucks, R.G.; Handford, C.R.

1996-12-31

Many carbonate reservoirs are the result of cave-forming processes. The origin and recognition of fractures, breccias, and sediment fills associated with paleocaves were determined through the study of modern and paleocaves systems. Cave formation and destruction are the products of near-surface processes. Near-surface processes include solutional excavation, clastic and chemical sedimentation, and collapse of cave walls and ceilings. Cave sediment is derived from inside and/or outside the system. Depositional mechanisms include suspension, tractional, mass-flow and rock-fall. Collapse of ceilings and walls from chaotic breakdown breccias. These piles can be tens of meters thick and contain large voids and variable amountsmore » of matrix. Cave-roof crackle breccia forms from stress-and tension-related fractures in cave-roof strata. As the cave-bearing strata subside into the subsurface, mechanical compaction increases and restructures the existing breccias and remaining cavities. Fracture porosity increases and breccia and vug porosity decreases. Large cavities collapse forming burial chaotic breakdown breccias. Differentially compacted strata over the collapsed chamber fracture and form burial cave-roof crackle breccias. Continued burial leads to more extensive mechanical compaction causing previously formed clasts to fracture and pack closer together. The resulting product is a rebrecciated chaotic breakdown breccia composed predominantly of small clasts. Rebrecciated blocks are often overprinted by crackling. Subsurface paleocave systems commonly have a complex history with several episodes of fracturing and brecciation. The resulting collapsed-paleocave reservoir targets are not single collapsed passages of tens of feet across, but are homogenized collapsed-cave systems hundreds to several thousand feet across.« less

Disturbed zones; indicators of deep-seated subsurface faults in the Valley and Ridge and Appalachian structural front of Pennsylvania

USGS Publications Warehouse

Pohn, Howard A.; Purdy, Terri L.

1982-01-01

Field studies of geologic structures in the Valley and Ridge and adjacent parts of the Appalachian Plateau provinces in Pennsylvania have shown a new type of structure, formerly poorly understood and frequently unmapped, is a significant indicator of deep-seated subsurface faulting. These structures, herein called disturbed zones, are formed by movement between closely spaced pairs of thrust faults. Disturbed zones are characterized at the surface by long, narrow, intensely folded and faulted zones of rocks in a relatively undisturbed stratigraphic sequence. These zones are frequently kilometers to tens of kilometers long and tens to hundreds of meters wide. Although disturbed zones generally occur in sequences of alternating siltstone and shale beds, they can also occur in other lithologies including massively-bedded sandstones and carbonates. Disturbed zones are not only easily recognized in outcrop but their presence can also be inferred on geologic maps by disharmonic fold patterns, which necessitates a detachment between adjacent units that show the disharmony. A number of geologic problems can be clarified by understanding the principles of the sequence of formation and the method of location of disturbed zones, including the interpretation of some published geologic cross sections and maps. The intense folding and faulting which accompanies the formation of a typical disturbed zone produces a region of fracture porosity which, if sealed off from the surface, might well serve as a commercially-exploitable hydrocarbon trap. We believe that the careful mapping of concentrations of disturbed zones can serve as an important exploration method which is much less expensive than speculation seismic lines.

Preservation of high primary porosity in Paleozoic crinoidal and bioclastic grainstones: Mississippian and Permian subsurface examples from western Canada and Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eby, D.E.; Kirkby, K.C.

1991-03-01

Limestone reservoirs with anomalously high porosity and permeability exist in several Paleozoic basinal settings in western North America. They are commonly either crinoidal or bioclastic grainstones that escaped the varied diagenetic environments that most carbonate shelves and slopes experience during sea-level fluctuations. Thus, these diagenetically 'conservative' settings can preserve most of the primary depositional porosity in calcarenites because of sedimentation and burial within normal marine basinal waters. These excellent reservoirs are often encased in deep marine, highly organic shales which may serve as both source rock and seal. Several subsurface examples of remarkable primary porosity occur within Mississippian Waulsortian buildupsmore » of western Canada and north-center Texas. Buildups within the Pekisko Formation of Alberta, for instance, contain abundant flanking crinoidal/bryozoan grainstones with up to 25% primary porosity and 10 d permeability. Muddy core facies with productive flank and capping calcarenites are up to 300 ft (90 m) thick and 600-1,200 ft (182-364 m) in diameter. The Bowar 'reef complex' in the Chappel Formation of Stephens County, Texas (2.6 MMBO to date) is similar in many respects to the Canadian buildups. Diagenetic 'conservatism' has also promoted excellent reservoir quality within the outer slope to basinal lower Permian bioclastic grain-flow deposit ('Wolfcamp detrital') plays of the eastern Midland basin where significant diagenesis was arrested after basinal deposition. Interpretations of these examples based upon core and outcrop control provide analogs for future exploration and exploitation in highly porous basinal carbonate reservoirs.« less

Predicting bulk permeability using outcrop fracture attributes: The benefits of a Maximum Likelihood Estimator

NASA Astrophysics Data System (ADS)

Rizzo, R. E.; Healy, D.; De Siena, L.

2015-12-01

The success of any model prediction is largely dependent on the accuracy with which its parameters are known. In characterising fracture networks in naturally fractured rocks, the main issues are related with the difficulties in accurately up- and down-scaling the parameters governing the distribution of fracture attributes. Optimal characterisation and analysis of fracture attributes (fracture lengths, apertures, orientations and densities) represents a fundamental step which can aid the estimation of permeability and fluid flow, which are of primary importance in a number of contexts ranging from hydrocarbon production in fractured reservoirs and reservoir stimulation by hydrofracturing, to geothermal energy extraction and deeper Earth systems, such as earthquakes and ocean floor hydrothermal venting. This work focuses on linking fracture data collected directly from outcrops to permeability estimation and fracture network modelling. Outcrop studies can supplement the limited data inherent to natural fractured systems in the subsurface. The study area is a highly fractured upper Miocene biosiliceous mudstone formation cropping out along the coastline north of Santa Cruz (California, USA). These unique outcrops exposes a recently active bitumen-bearing formation representing a geological analogue of a fractured top seal. In order to validate field observations as useful analogues of subsurface reservoirs, we describe a methodology of statistical analysis for more accurate probability distribution of fracture attributes, using Maximum Likelihood Estimators. These procedures aim to understand whether the average permeability of a fracture network can be predicted reducing its uncertainties, and if outcrop measurements of fracture attributes can be used directly to generate statistically identical fracture network models.

Carbonation of mantle peridotites: implications for permanent geological CO2 capture and storage

NASA Astrophysics Data System (ADS)

Paukert, A. N.; Matter, J. M.; Kelemen, P. B.; Marsala, P.; Shock, E.

2012-12-01

In situ carbonation of mantle peridotites serves as a natural analog to engineered mineral carbonation for geological CO2 capture and storage. For example, mantle peridotite in the Samail Ophiolite, Oman naturally captures and stores about 5x104 tons of atmospheric CO2 per year as carbonate minerals, and has been doing so for the past 50,000 years [Kelemen et al., 2011]. Our reaction path modeling of this system shows that the natural process is limited by subsurface availability of dissolved inorganic carbon, and that the rate of CO2 mineralization could be enhanced by a factor of 16,000 by injecting CO2 into the peridotite aquifer at 2 km depth and a fugacity of 100 bars. Injecting CO2 into mafic or ultramafic rock formations has been presumed difficult, as fractured crystalline rocks typically have low porosity and permeability; however these factors have yet to be comprehensively studied. To determine the actual value of these hydrogeological factors, this winter we carried out a multifaceted study of deep boreholes (up to 350m) in the mantle peridotite and the Moho transition zone of the Samail Ophiolite. A suite of physical and chemical parameters were collected, including slug tests for hydraulic conductivity, geophysical well logs for porosity and hydraulic conductivity, drill chips for extent and composition of secondary mineralization, and water and dissolved gas samples for chemical composition. All of these factors combine to provide a comprehensive look at the chemical and physical processes underlying natural mineral carbonation in mantle peridotites. Understanding the natural process is critical, as mineral carbonation in ultramafic rocks is being explored as a permanent and relatively safe option for geologic carbon sequestration. While injectivity in these ultramafic formations was believed to be low, our slug test and geophysical well log data suggest that the hydraulic conductivity of fractured peridotites can actually be fairly high - up to meters/day, on par with fine to medium grained sandstones - so these formations may be more suitable than previously thought. Using the Samail Ophiolite as a natural analog for in situ mineral carbonation in ultramafic rocks should help predict and optimize the efficacy and security of engineered CO2 storage projects.

Uranium migration and favourable sites of potential radioelement concentrations in Gabal Umm Hammad area, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Youssef, Mohamed A. S.; Sabra, Mohamed Elsadek M.; Abdeldayem, Abdelaziz L.; Masoud, Alaa A.; Mansour, Salah A.

2017-12-01

Airborne gamma-ray spectrometric data, covering Gabal Umm Hammad area, near Quseir City, in the Eastern Desert of Egypt, has been utilized to identify the uranium migration path, and U, Th and K-favorability indices. The following of the uranium migration technique enabled estimation of the amount of migrated uranium, in and out of the rock units. Investigation of the Taref Formation, Nakhil Formation, Tarawan Formation and Dawi Formation shows large negative amount of uranium migration, indicating that uranium leaching is outward from the geologic body toward surrounding rock units. Moreover, calculation of the U, Th and K-favorability indices has been carried out for the various rock units to locate the rocks having the highest radioelement potentialities. The rock units that possess relatively major probability of uranium potentiality include Mu‧tiq Group, weakly deformed granitic rocks, and Trachyte plugs and sheets. Meanwhile, the rock units with major potential of Th-index are Taref Formation, Quseir Formation and Dawi Formation. The rock units with major potential of K-index are Dokhan volcanic and Mu‧tiq group.

Summary of the Issues Regarding The Martian Subsurface Explorer

NASA Technical Reports Server (NTRS)

Eustes, A. W., III; Gertsch, L. S.; Lu, N.; Bridgford, E.; Tischler, A.; Stoner, M. S.; Wilcox, B. H.

2000-01-01

This is a summary of research work accomplished to date for the Jet Propulsion Laboratory by the Colorado School of Mines and the Michigan Technological University for the Martian Subsurface Explorer (SSX). The task involved a thorough review of the state of the art in drilling in the petroleum and mining industries in the following areas: 1) Drilling mechanics and energy requirements. 2) Sidewall friction in boreholes. 3) Rock property characteristics of basalt, permafrost, and ice. 4) Cuttings transport and recompaction of cuttings. and 5) Directional control at odd angle interfaces.

Constructed wetlands and waste stabilization ponds for small rural communities in the United Kingdom: a comparison of land area requirements, performance and costs.

PubMed

Mara, D D

2006-07-01

Land area requirements for secondary subsurface horizontal-flow constructed wetlands (CW) and primary and secondary facultative ponds with either unaerated or aerated rock filters were determined for three levels of effluent quality: that specified in the Urban Waste Water Treatment Directive (UWWTD) (< or = 25 mg filtered BOD l(-1) and < or = 150 mg SS l(-1) for waste stabilization ponds (WSP) effluents, and < or = 25 mg unfiltered BOD l(-1) for CW effluents (mean values); and two common requirements of the Environment Agency: < or = 40 mg BOD l(-1) and < or = 60 mg SS l(-1), and < or = 10 mg BOD l(-1), < or = 15 mg SS l(-1) and < or = 5 mg ammonia-N l(-1) (95-percentile values). A secondary CW requires 60 percent more land than a secondary facultative pond to produce an UWWTD-quality effluent, 38 percent more land than a secondary facultative pond and an unaerated rock filter to produce a 40/60 effluent and, were it to be used to produce a 10/15/5 effluent, it would require approximately 480 percent more land than a secondary facultative pond and an aerated rock filter. Its estimated 2005 cost is pound 1100-2600 p.e.(-1), whereas that of a primary facultative pond and rock filter is approximately pound 400 p.e.(-1). On the basis of land area requirements, performance and cost, facultative ponds and unaerated or aerated rock filters are to be preferred to secondary subsurface horizontal-flow constructed wetlands.

Location, Reprocessing, and Analysis of Two Dimensional Seismic Reflection Data on the Jicarilla Apache Indian Reservation, New Mexico, Final Report, September 1, 1997-February 1, 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ridgley, Jennie; Taylor, David J.; Huffman, Jr., A. Curtis

2000-06-08

Multichannel surface seismic reflection data recording is a standard industry tool used to examine various aspects of geology, especially the stratigraphic characteristics and structural style of sedimentary formations in the subsurface. With the help of the Jicarilla Apache Tribe and the Bureau of Indian Affairs we were able to locate over 800 kilometers (500 miles) of multichannel seismic reflection data located on the Jicarilla Apache Indian reservation. Most of the data was received in hardcopy form, but there were data sets where either the demultiplexed digital field data or the processed data accompanied the hardcopy sections. The seismic data wasmore » acquired from the mid 1960's to the early 1990's. The most extensive seismic coverage is in the southern part of the reservation, although there are two good surveys located on the northeastern and northwestern parts of the reservation. Most of the data show that subsurface formations are generally flat-lying in the southern and western portion of the reservation. There is, however, a significant amount of structure imaged on seismic data located over the San Juan Basin margin along the east-central and northern part of the reservation. Several west to east trending lines in these areas show a highly faulted monoclinal structure from the deep basin in the west up onto the basin margin to the east. Hydrocarbon exploration in flat lying formations is mostly stratigraphic in nature. Where there is structure in the subsurface and indications are that rocks have been folded, faulted, and fractured, exploration has concentrated on structural traps and porosity/permeability "sweet spots" caused by fracturing. Therefore, an understanding of the tectonics influencing the entire section is critical in understanding mechanisms for generating faults and fractures in the Cretaceous. It is apparent that much of the hydrocarbon production on the reservation is from fracture porosity in either source or reservoir sequences. Therefore it is important to understand the mechanism that controls the location and intensity of the fractures. A possible mechanism may be deep seated basement faulting that has been active through time. Examining the basement fault patterns in this part of the basin and their relation to fracture production may provide a model for new plays on the Jicarilla Indian Reservation. There are still parts of the reservation where the subsurface has not been imaged geophysically with either conventional two-dimensional or three-dimensional reflection seismic techniques. These methods, especially 3-D seismic, would provide the best data for mapping deep basement faulting. The authors would recommend that 3-D seismic be acquired along the Basin margin located along the eastern edge of the reservation and the results be used to construct detailed fault maps which may help to locate areas with the potential to contain highly fractured zones in the subsurface.« less

Uncertainty evaluation with increasing borehole drilling in subsurface hydrogeological explorations

NASA Astrophysics Data System (ADS)

Amano, K.; Ohyama, T.; Kumamoto, S.; Shimo, M.

2016-12-01

Quantities of drilling boreholes have been a difficult subject for field investigators in such as subsurface hydrogeological explorations. This problem becomes a bigger in heterogeneous formations or rock masses so we need to develop quantitative criteria for evaluating uncertainties during borehole investigations.To test an uncertainty reduction with increasing boreholes, we prepared a simple hydrogeological model and virtual hydraulic tests were carried out by using this model. The model consists of 125,000 elements of which hydraulic conductivities are generated randomly from the log-normal distribution in a 2-kilometer cube. Uncertainties were calculated by the difference of head distributions between the original model and the inchoate models made by virtual hydraulic test one by one.The results show the level and the variance of uncertainty are strongly correlated to the average and variance of the hydraulic conductivities. This kind of trends also could be seen in the actual field data obtained from the deep borehole investigations in Horonobe Town, northern Hokkaido, Japan. Here, a new approach using fractional bias (FB) and normalized mean square error (NMSE) for evaluating uncertainty characteristics will be introduced and the possibility of use as an indicator for decision making (i.e. to stop borehole drilling or to continue borehole drilling) in field investigations will be discussed.

Optimization of subsurface flow and associated treatment processes.

DOT National Transportation Integrated Search

2006-02-01

The objective of this study was to examine the use and performance of synthetic media (growth substrate) in a rock filter waste treatment system located at the Grand Prairie Rest Area. Specifically, this study examined the performance of the syntheti...

Method for formation of subsurface barriers using viscous colloids

DOEpatents

Apps, J.A.; Persoff, P.; Moridis, G.; Pruess, K.

1998-11-17

A method is described for formation of subsurface barriers using viscous liquids where a viscous liquid solidifies at a controlled rate after injection into soil and forms impermeable isolation of the material enclosed within the subsurface barriers. The viscous liquid is selected from the group consisting of polybutenes, polysiloxanes, colloidal silica and modified colloidal silica of which solidification is controlled by gelling, cooling or cross-linking. Solidification timing is controlled by dilution, addition of brines, coating with alumina, stabilization with various agents and by temperature. 17 figs.

Interpretation of Late Cretaceous Volcanic Mounds and Surrounding Gulfian Series Formations Using 3D Seismic Data in Zavala County, Texas

NASA Astrophysics Data System (ADS)

Bennett, Laura Claire

The Late Cretaceous Gulfian series is a prominent and important series across the State of Texas that has been extensively studied since the nineteenth century. It is composed of series of southeast-dipping shelf carbonates and clastics deposited on the northwest margin of the Gulf of Mexico Basin. In south Texas, the Gulfian series was deposited in the Rio Grande Embayment and Maverick Basin and is comprised of the Eagle Ford Group, Austin Group, Anacacho Limestone, San Miguel Formation, Olmos Formation, and Escondido Formation that crop out and continue basinward in the subsurface. Late Cretaceous volcanism formed volcanic mounds composed of altered palagonite tuff that are clustered into two fields, including the Uvalde Field centered in Zavala County. Using the Pedernales 3D seismic survey, located in east-central Zavala County, several volcanic mounds were identified and mapped without the use of well log data by identifying structures and characteristics associated with the volcanic mounds. Isolating these mounds through mapping enabled the mapping of the tops surrounding Gulfian formations, Lower Eagle Ford, Upper Eagle Ford, Austin, Anacacho, and San Miguel, for which time-structure, amplitude, similarity/coherency attribute, and isochron maps were generated. By using 3D seismic data, the volcanic mounds and their relation to surrounding rocks can be better interpreted.

Episodic sediment-discharge events in Cascade Springs, southern Black Hills, South Dakota

USGS Publications Warehouse

Hayes, Timothy Scott

1999-01-01

Cascade Springs is a group of artesian springs in the southern Black Hills, South Dakota, with collective flow of about 19.6 cubic feet per second. Beginning on February 28, 1992, a large discharge of red suspended sediment was observed from two of the six known discharge points. Similar events during 1906-07 and 1969 were documented by local residents and newspaper accounts. Mineralogic and grain-size analyses were performed to identify probable subsurface sources of the sediment. Geochemical modeling was performed to evaluate the geochemical evolution of water discharged from Cascade Springs. Interpretations of results provide a perspective on the role of artesian springs in the regional geohydrologic framework. X-ray diffraction mineralogic analyses of the clay fraction of the suspended sediment were compared to analyses of clay-fraction samples taken from nine geologic units at and stratigraphically below the spring-discharge points. Ongoing development of a subsurface breccia pipe(s) in the upper Minnelusa Formation and/or Opeche Shale was identified as a likely source of the suspended sediment; thus, exposed breccia pipes in lower Hell Canyon were examined. Upper Minnelusa Formation breccia pipes in lower Hell Canyon occur in clusters similar to the discrete discharge points of Cascade Springs. Grain-size analyses showed that breccia masses lack clay fractions and have coarser distributions than the wall rocks, which indicates that the red, fine-grained fractions have been carried out as suspended sediment. These findings support the hypothesis that many breccia pipes were formed as throats of abandoned artesian springs. Geochemical modeling was used to test whether geochemical evolution of ground water is consistent with this hypothesis. The evolution of water at Cascade Springs could not be suitably simulated using only upgradient water from the Minnelusa aquifer. A suitable model involved dissolution of anhydrite accompanied by dedolomitization in the upper Minnelusa Formation, which is caused by upward leakage of relatively fresh water from the Madison aquifer. The anhydrite dissolution and dedolomitization account for the net removal of minerals that would lead to breccia pipe formation by gravitational collapse. Breccia pipes in the lower Minnelusa Formation are uncommon; however, networks of interconnected breccia layers and breccia dikes are common. These networks, along with vertical fractures and faults, are likely pathways for transmitting upward leakage from the Madison aquifer. It is concluded that suspended sediment discharged at Cascade Springs probably results from episodic collapse brecciation that is caused by subsurface dissolution of anhydrite beds and cements of the upper Minnelusa Formation, accompanied by replacement of dolomite by calcite. It is further concluded that many breccia pipes probably are the throats of artesian springs that have been abandoned and exposed by erosion. The locations of artesian spring-discharge points probably have been shifting outwards from the center of the Black Hills uplift, essentially keeping pace with regional erosion over geologic time. Thus, artesian springflow probably is a factor in controlling water levels in the Madison and Minnelusa aquifers, with hydraulic head declining over geologic time, in response to development of new discharge points. Development of breccia pipes as throats of artesian springs would greatly enhance vertical hydraulic conductivity in the immediate vicinity of spring-discharge points. Horizontal hydraulic conductivity in the Minnelusa Formation also may be enhanced by dissolution processes related to upward leakage from the Madison aquifer. Potential processes could include dissolution resulting from leakage in the vicinity of breccia pipes that are abandoned spring throats, active spring discharge, development of subsurface breccias with no visible surface expression or spring discharge, as well as general areal leakage

New insights into the nation's carbon storage potential

USGS Publications Warehouse

Warwick, Peter D.; Zhu, Zhi-Liang

2012-01-01

Carbon sequestration is a method of securing carbon dioxide (CO2) to prevent its release into the atmosphere, where it contributes to global warming as a greenhouse gas. Geologic storage of CO2 in porous and permeable rocks involves injecting high-pressure CO2 into a subsurface rock unit that has available pore space. Biologic carbon sequestration refers to both natural and anthropogenic processes by which CO2 is removed from the atmosphere and stored as carbon in vegetation, soils, and sediments.

Numerical Analysis on the Rheology of Martian Lobate Debris Aprons

NASA Astrophysics Data System (ADS)

Li, H.; Jing, H.; Zhang, H.; Shi, Y.

2011-10-01

Occurrence of ice in Martian subsurface is indicated by landforms such as lobate debris aprons (LDAs), concentric crater fills, and softened terrains. We used a three dimensional non-Newtonian viscous finite element model to investigate the behavior of ice-rock mixtures numerically. Our preliminary simulation results show that when the volume of rock is less than 40%, the rheology of the mixture is dominated by ice, and there exists a brittle-ductile transition when ice fraction reaches a certain value.

Introduction: energy and the subsurface.

PubMed

Christov, Ivan C; Viswanathan, Hari S

2016-10-13

This theme issue covers topics at the forefront of scientific research on energy and the subsurface, ranging from carbon dioxide (CO2) sequestration to the recovery of unconventional shale oil and gas resources through hydraulic fracturing. As such, the goal of this theme issue is to have an impact on the scientific community, broadly, by providing a self-contained collection of articles contributing to and reviewing the state-of-the-art of the field. This collection of articles could be used, for example, to set the next generation of research directions, while also being useful as a self-study guide for those interested in entering the field. Review articles are included on the topics of hydraulic fracturing as a multiscale problem, numerical modelling of hydraulic fracture propagation, the role of computational sciences in the upstream oil and gas industry and chemohydrodynamic patterns in porous media. Complementing the reviews is a set of original research papers covering growth models for branched hydraulic crack systems, fluid-driven crack propagation in elastic matrices, elastic and inelastic deformation of fluid-saturated rock, reaction front propagation in fracture matrices, the effects of rock mineralogy and pore structure on stress-dependent permeability of shales, topographic viscous fingering and plume dynamics in porous media convection.This article is part of the themed issue 'Energy and the subsurface'. © 2016 The Author(s).

Installation restoration research program: Assessment of geophysical methods for subsurface geologic mapping, cluster 13, Edgewood Area, Aberdeen Proving Ground, Maryland. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, D.K.; Sharp, M.K.; Sjostrom, K.J.

1996-10-01

Seismic refraction, electrical resistivity, and transient electromagnetic surveys were conducted at a portion of Cluster 13, Edgewood Area of Aberdeen Proving Ground, Maryland. Seismic refraction cross sections map the topsoil layer and the water table (saturated zone). The water table elevations from the seismic surveys correlate closely with water table elevations in nearby monitoring wells. Electrical resistivity cross sections reveal a very complicated distribution of sandy and clayey facies in the upper 10 - 15 m of the subsurface. A continuous surficial (topsoil) layer correlates with the surficial layer of the seismic section and nearby boring logs. The complexity andmore » details of the electrical resistivity cross section correlate well with boring and geophysical logs from nearby wells. The transient electromagnetic surveys map the Pleistocene-Cretaceous boundary, the saprolite, and the top of the Precambrian crystalline rocks. Conducting the transient electromagnetic surveys on a grid pattern allows the construction of a three-dimensional representation of subsurface geology (as represented by variations of electrical resistivity). Thickness and depth of the saprolitic layer and depth to top of the Precambrian rocks are consistent with generalized geologic cross sections for the Edgewood Area and depths projected from reported depths at the Aberdeen Proving Ground NW boundary using regional dips.« less

Chemical indicators of subsurface temperature applied to hot spring waters of Yellowstone National Park, Wyoming, U.S.A.

USGS Publications Warehouse

Fournier, R.O.; Truesdell, A.H.

1970-01-01

Under favorable conditions the chemistry of hot springs may give reliable indications of subsurface temperatures and circulation patterns. These chemical indicators can be classified by the type of process involved: {A table is presented}. All these indicators have certain limitations. The silica geothermometer gives results independent of the local mineral suite and gas partial pressures, but may be affected by dilution. Alkali ratios are strongly affected by the local mineral suite and the formation of complex ions. Carbonate-chloride ratios are strongly affected by subsurface PCO2. The relative concentration of volatiles can be very misleading in high-pressure liquid systems. In Yellowstone National Park most thermal waters issue from hot, shallow aquifers with pressures in excess of hydrostatic by 2 to 6 bars and with large flows (the flow of hot spring water from the Park is greater than 4000 liters per second). These conditions should be ideal for the use of chemical indicators to estimate aquifer temperatures. In five drill holes aquifer temperatures were within 2??C of that predicted from the silica content of nearby hot springs; the temperature level off at a lower value than predicted in only one hole, and in four other holes drilling was terminated before the predicted aquifer temperature was reached. The temperature-Na/K ratio relationship does not follow any published experimental or empirical curve for water-feldspar or water-clay reactions. We suspect that ion exchange reactions involving zeolites in the Yellowstone rocks result in higher Na/K ratios at given temperatures than result from feldspar or clay reactions. Comparison of SiO2 and Cl/(HCO3 + CO3) suggest that because of higher subsurface PCO2 in Upper Geyser Basin a given Cl/(HCO3 + CO3) ratio there means a higher temperature than in Lower Geyser Basin. No correlation was found in Yellowstone Park between the subsurface regions of highest temperature and the relative concentration of volatile components such as boron and ammonia. ?? 1971.

How deep can surface signals be traced in the critical zone? Merging biodiversity with biogeochemistry research in a central German Muschelkalk landscape

NASA Astrophysics Data System (ADS)

Küsel, Kirsten; Totsche, Kai; Trumbore, Susan; Lehmann, Robert; Steinhäuser, Christine; Herrmann, Martina

2016-04-01

The Earth's Critical Zone (CZ) is a thin living layer connecting atmosphere and geosphere, including aquifers. Humans live in the CZ and benefit from the vital supporting services it provides. However, the CZ is increasingly impacted by human activities including land and resource use, pollution and climate change. Recent interest in uniting the many disciplines studying this complex domain has initiated an international network of research infrastructure platforms that allow access to the CZ in a range of geologic settings. In this paper a new such infrastructure platform associated with the Collaborative Research Center AquaDiva is described, that uniquely seeks to combine CZ research with detailed investigation of the functional biodiversity of the subsurface. Overall, AquaDiva aims to test hypotheses about how water connects surface conditions set by land cover and land management to the biota and biogeochemical functions in the subsurface. With long-term and continuous observations, hypotheses about how seasonal variations and extreme events at the surface impact subsurface processes, community structure and function, are tested. AquaDiva has established the Hainich Critical Zone Exploratory (CZE) in central Germany in an alkaline geological setting of German Triassic Muschelkalk formations. The Hainich CZE includes specialized monitoring wells to access the vadose zone and two main groundwater complexes in limestone and marlstone parent materials along a ~6 km transect spanning forest, pasture and agricultural land uses. Initial results demonstrate fundamental differences in the biota and biogeochemistry of the two aquifer complexes that trace back to the land uses in their respective recharge areas. They also show the importance of antecedent conditions on the impact of precipitation events on responses in terms of groundwater dynamics, chemistry and ecology. Thus we find signals of surface land use and events can be detected in the subsurface CZ. Future research will expand to a second CZE in contrasting siliciclastic parent rock, to evaluate the relative importance of parent material lithology versus surface conditions for the emergent characteristics of the subsurface CZ and biodiversity. The Hainich CZE is open to researchers who bring new questions that the research platform can help answer.

Microbial diversity in ultra-high-pressure rocks and fluids from the Chinese Continental Scientific Drilling Project in China.

PubMed

Zhang, Gengxin; Dong, Hailiang; Xu, Zhiqin; Zhao, Donggao; Zhang, Chuanlun

2005-06-01

Microbial communities in ultra-high-pressure (UHP) rocks and drilling fluids from the Chinese Continental Scientific Drilling Project were characterized. The rocks had a porosity of 1 to 3.5% and a permeability of approximately 0.5 mDarcy. Abundant fluid and gas inclusions were present in the minerals. The rocks contained significant amounts of Fe2O3, FeO, P2O5, and nitrate (3 to 16 ppm). Acridine orange direct counting and phospholipid fatty acid analysis indicated that the total counts in the rocks and the fluids were 5.2 x 10(3) to 2.4 x 10(4) cells/g and 3.5 x 10(8) to 4.2 x 10(9) cells/g, respectively. Enrichment assays resulted in successful growth of thermophilic and alkaliphilic bacteria from the fluids, and some of these bacteria reduced Fe(III) to magnetite. 16S rRNA gene analyses indicated that the rocks were dominated by sequences similar to sequences of Proteobacteria and that most organisms were related to nitrate reducers from a saline, alkaline, cold habitat; however, some phylotypes were either members of a novel lineage or closely related to uncultured clones. The bacterial communities in the fluids were more diverse and included Proteobacteria, Bacteroidetes, gram-positive bacteria, Planctomycetes, and Candidatus taxa. The archaeal diversity was lower, and most sequences were not related to any known cultivated species. Some archaeal sequences were 90 to 95% similar to sequences recovered from ocean sediments or other subsurface environments. Some archaeal sequences from the drilling fluids were >93% similar to sequences of Sulfolobus solfataricus, and the thermophilic nature was consistent with the in situ temperature. We inferred that the microbes in the UHP rocks reside in fluid and gas inclusions, whereas those in the drilling fluids may be derived from subsurface fluids.

Microbial Diversity in Ultra-High-Pressure Rocks and Fluids from the Chinese Continental Scientific Drilling Project in China

PubMed Central

Zhang, Gengxin; Dong, Hailiang; Xu, Zhiqin; Zhao, Donggao; Zhang, Chuanlun

2005-01-01

Microbial communities in ultra-high-pressure (UHP) rocks and drilling fluids from the Chinese Continental Scientific Drilling Project were characterized. The rocks had a porosity of 1 to 3.5% and a permeability of ∼0.5 mDarcy. Abundant fluid and gas inclusions were present in the minerals. The rocks contained significant amounts of Fe2O3, FeO, P2O5, and nitrate (3 to 16 ppm). Acridine orange direct counting and phospholipid fatty acid analysis indicated that the total counts in the rocks and the fluids were 5.2 × 103 to 2.4 × 104 cells/g and 3.5 × 108 to 4.2 × 109 cells/g, respectively. Enrichment assays resulted in successful growth of thermophilic and alkaliphilic bacteria from the fluids, and some of these bacteria reduced Fe(III) to magnetite. 16S rRNA gene analyses indicated that the rocks were dominated by sequences similar to sequences of Proteobacteria and that most organisms were related to nitrate reducers from a saline, alkaline, cold habitat; however, some phylotypes were either members of a novel lineage or closely related to uncultured clones. The bacterial communities in the fluids were more diverse and included Proteobacteria, Bacteroidetes, gram-positive bacteria, Planctomycetes, and Candidatus taxa. The archaeal diversity was lower, and most sequences were not related to any known cultivated species. Some archaeal sequences were 90 to 95% similar to sequences recovered from ocean sediments or other subsurface environments. Some archaeal sequences from the drilling fluids were >93% similar to sequences of Sulfolobus solfataricus, and the thermophilic nature was consistent with the in situ temperature. We inferred that the microbes in the UHP rocks reside in fluid and gas inclusions, whereas those in the drilling fluids may be derived from subsurface fluids. PMID:15933024

Understanding Shale Gas: Recent Progress and Remaining Challenges

DOE PAGES

Striolo, Alberto; Cole, David R.

2017-08-27

Because of a number of technological advancements, unconventional hydrocarbons, and in particular shale gas, have transformed the US economy. Much is being learned, as demonstrated by the reduced cost of extracting shale gas in the US over the past five years. However, a number of challenges still need to be addressed. Many of these challenges represent grand scientific and technological tasks, overcoming which will have a number of positive impacts, ranging from the reduction of the environmental footprint of shale gas production to improvements and leaps forward in diverse sectors, including chemical manufacturing and catalytic transformations. This review addresses recentmore » advancements in computational and experimental approaches, which led to improved understanding of, in particular, structure and transport of fluids, including hydrocarbons, electrolytes, water, and CO 2 in heterogeneous subsurface rocks such as those typically found in shale formations. Finally, the narrative is concluded with a suggestion of a few research directions that, by synergistically combining computational and experimental advances, could allow us to overcome some of the hurdles that currently hinder the production of hydrocarbons from shale formations.« less

Refinement of determination of critical thresholds of stress-strain behaviour by using AE data: potential for evaluation of durability of natural stone

NASA Astrophysics Data System (ADS)

Prikryl, Richard; Lokajíček, Tomáš

2017-04-01

According to previous studies, evaluation of stress-strain behaviour (in uniaxial compression) of various rocks appears to be effective tool allowing for prediction of resistance of natural stone to some physical weathering processes. Precise determination of critical thresholds, specifically of 'crack initiation' and 'crack damage' is fundamental issue in this approach. In contrast to 'crack damage stress/strain threshold', which can be easily read from deflection point on volumetric curve, detection of 'crack initiation' is much more difficult. Besides previously proposed mathematical processing of axial stress-strain curve, recording of acoustic emission (AE) data and their processing provide direct measure of various stress/strain thresholds, specifically of 'crack initiation'. This specific parameter is required during successive computation of energetic parameters (mechanical work), that can be stored by a material without formation of new defects (microcracks) due to acting stress. Based on our experimental data, this mechanical work seems to be proportional to the resistance of a material to formation of mode I (tensile) cracks that are responsible for destruction of subsurface below exposed faces of natural stone.

In situ spectroscopic identification of neptunium(V) inner-sphere complexes on the hematite-water interface.

PubMed

Müller, Katharina; Gröschel, Annett; Rossberg, André; Bok, Frank; Franzen, Carola; Brendler, Vinzenz; Foerstendorf, Harald

2015-02-17

Hematite plays a decisive role in regulating the mobility of contaminants in rocks and soils. The Np(V) reactions at the hematite-water interface were comprehensively investigated by a combined approach of in situ vibrational spectroscopy, X-ray absorption spectroscopy and surface complexation modeling. A variety of sorption parameters such as Np(V) concentration, pH, ionic strength, and the presence of bicarbonate was considered. Time-resolved IR spectroscopic sorption experiments at the iron oxide-water interface evidenced the formation of a single monomer Np(V) inner-sphere sorption complex. EXAFS provided complementary information on bidentate edge-sharing coordination. In the presence of atmospherically derived bicarbonate the formation of the bis-carbonato inner-sphere complex was confirmed supporting previous EXAFS findings.1 The obtained molecular structure allows more reliable surface complexation modeling of recent and future macroscopic data. Such confident modeling is mandatory for evaluating water contamination and for predicting the fate and migration of radioactive contaminants in the subsurface environment as it might occur in the vicinity of a radioactive waste repository or a reprocessing plant.

Geology and ground water of the Savannah River Plant and vicinity, South Carolina

USGS Publications Warehouse

Siple, George E.

1967-01-01

The area described in this report covers approximately 2,600 square miles in west-central South Carolina and includes the site of the Savannah River Plant, a major production facility of the U.S. Atomic Energy Commission. The climate, surface drainage, and land forms of the study area are typical of the southern part of the Atlantic Coastal Plain. Precipitation is normally abundant and fairly evenly distributed throughout the year, and the mean annual temperature is moderately warm (64?F). The major streams that drain the area (the Savannah, Salkehatchie, and Edisto Rivers) have low gradients and flow in a southeasterly direction toward the Atlantic Ocean. Surface features of the area include narrow, flat-bottomed, steep-sided valleys and broad gently rolling interfluvial areas. Those parts of the Coastal Plain included within the report area can be subdivided into the Aiken Plateau, the Congaree Sandhills, and the Coastal Terraces. The area is underlain by a sequence of unconsolidated and partly consolidated sediments of Late Cretaceous, Tertiary, and Quaternary age. The unconsolidated sediments were deposited unconformably on a basement of igneous and metamorphic rocks of Precambrian and Paleozoic age and sedimentary rocks of Triassic age. The basement rocks are similar to the granite-diorite complex of the Charlotte Belt, the metamorphosed rocks of the Carolina Slate Belt, and the consolidated sediments of the Newark Group. The unconsolidated sediments strike about N. 60 ? E. and dip 6-20 feet per mile to the southeast. They form a wedge-shaped mass that increases in thickness toward the southeast to slightly more than 1,200 feet in the vicinity of Allendale, S.C., on the southeast or downdip side of the study area. The oldest or lowermost unconsolidated sedimentary unit, the Tuscaloosa Formation of Late Cretaceous age, is overlain in the subsurface by beds that are also probably Late Cretaceous in age and that herein are named the Ellenton Formation. The Upper Cretaceous deposits are, in turn, overlain by the, McBean Formation and the Congaree(?) Formation of middle Eocene age, the Barnwell Formation of late Eocene age, the Hawthorn Formation of early and middle Miocene age, and by fluvial and marine(?) terrace deposits of Pliocene(?), Pleistocene, and Recent age. In the mapped area, the Congaree(?) Formation includes undifferentiated rocks (mostly Congaree and Barnwell Formations and some Mcbean outliers). (See map explanation.) Structurally, the Upper Cretaceous sediments are overlapped to the northwest by Tertiary deposits. A preliminary geologic map of the general area is included in the report. The principal aquifer in the area is composed of the beds of medium to coarse sand and gravel contained in the Tuscaloosa and Ellenton Formations. Subordinate aquifers include deposits of sand and limestone of Tertiary and Quaternary age. The ground water in the principal aquifer occurs under water-table conditions in the outcrop area of the Tuscaloosa Formation in the northern and western parts of the study area, but it is under artesian pressure downdip in the southern and eastern parts of the study area. Contours drawn on the piezometric surface of the water in the principal aquifer indicate that water is recharged to the aquifer mainly by leakage through the overlying Tertiary formations. Likewise, the piezometric contours show that the outcrop area of the Tuscaloosa Formation functions chiefly as an area of discharge. Doubtless, water is also discharged from the aquifer by moving downdip to areas near the coast where the prevailing hydraulic gradient may favor the upward leakage of water through the upper confining beds. The hydraulic properties of the principal aquifer were determined by a series of pumping tests. The results indicate that the aquifer is highly productive and could supply 15 million gallons per day in the vicinity of the Savannah River Plant without exceeding the available drawdown. Gr

Quantification of metal loads by tracer injection and synoptic sampling in Daisy Creek and the Stillwater River, Park County, Montana, August 1999

USGS Publications Warehouse

Nimick, David A.; Cleasby, Thomas E.

2001-01-01

A metal-loading study using tracer-injection and synoptic-sampling methods was conducted in Daisy Creek and a short reach of the Stillwater River during baseflow in August 1999 to quantify the metal inputs from acid rock drainage in the New World Mining District near Yellowstone National Park and to examine the downstream transport of these metals into the Stillwater River. Loads were calculated for many mainstem and inflow sites by combining streamflow determined using the tracer-injection method with concentrations of major ions and metals that were determined in synoptic water-quality samples. Water quality and aquatic habitat in Daisy Creek have been affected adversely by drainage derived from waste rock and adit discharge at the McLaren Mine as well as from natural weathering of pyrite-rich mineralized rock that comprises and surrounds the ore zones. However, the specific sources and transport pathways are not well understood. Knowledge of the main sources and transport pathways of metals and acid can aid resource managers in planning and conducting effective and cost-efficient remediation activities. The metals cadmium, copper, lead, and zinc occur at concentrations that are sufficiently elevated to be potentially lethal to aquatic life in Daisy Creek and to pose a toxicity risk in part of the Stillwater River. Copper is of most concern in Daisy Creek because it occurs at higher concentrations than the other metals. Acidic surface inflows had dissolved concentrations as high as 20.6 micrograms per liter (?g/L) cadmium, 26,900 ?g/L copper, 76.4 ?g/L lead, and 3,000 ?g/L zinc. These inflows resulted in maximum dissolved concentrations in Daisy Creek of 5.8 ?g/L cadmium, 5,790 ?g/L copper, 3.8 ?g/L lead, and 848 ?g/L zinc. Significant copper loading to Daisy Creek occurred only in the upper half of the stream. Sources included subsurface inflow and right-bank (mined side) surface inflows. Copper loads in left-bank (unmined side) surface inflows were negligible. Most (71 percent) of the total copper loading in the study reach occurred along a 341-foot reach near the stream?s headwaters. About 53 percent of the total copper load was contributed by five surface inflows that drain a manganese bog and the southern part of the McLaren Mine. Copper loading from subsurface inflow was substantial, contributing 46 percent of the total dissolved copper load to Daisy Creek. More than half of this subsurface copper loading occurred downstream from the reaches that received significant surface loading. Flow through the shallow subsurface appears to be the main copper-transport pathway from the McLaren Mine and surrounding altered and mineralized bedrock to Daisy Creek during base-flow conditions. Little is known about the source of acid and copper in this subsurface flow. However, possible sources include the mineralized rocks of Fisher Mountain upgradient of the McLaren Mine area, the surficial waste rock at the mine, and the underlying pyritic bedrock.

Probing the deep critical zone beneath the Luquillo Experimental Forest, Puerto Rico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buss, Heather; Brantley, S. L.; Scatena, Fred

2013-01-01

Recent work has suggested that weathering processes occurring in the subsurface produce the majority of silicate weathering products discharged to the world s oceans, thereby exerting a primary control on global temperature via the well-known positive feedback between silicate weathering and CO2. In addition, chemical and physical weathering processes deep within the critical zone create aquifers and control groundwater chemistry, watershed geometry and regolith formation rates. Despite this, most weathering studies are restricted to the shallow critical zone (e.g., soils, outcrops). Here we investigate the chemical weathering, fracturing and geomorphology of the deep critical zone in the Bisley watershed inmore » the Luquillo Critical Zone Observatory, Puerto Rico, from two boreholes drilled to 37.2 and 27.0 m depth, from which continuous core samples were taken. Corestones exposed aboveground were also sampled. Weathered rinds developed on exposed corestones and along fracture surfaces on subsurface rocks slough off of exposed corestones once rinds attain a thickness up to ~1 cm, preventing the corestones from rounding due to diffusion limitation. Such corestones at the land surface are assumed to be what remains after exhumation of similar, fractured bedrock pieces that were observed in the drilled cores between thick layers of regolith. Some of these subsurface corestones are massive and others are highly fractured, whereas aboveground corestones are generally massive with little to no apparent fracturing. Subsurface corestones are larger and less fractured in the borehole drilled on a road where it crosses a ridge compared to the borehole drilled where the road crosses the stream channel. Both borehole profiles indicate that the weathering zone extends to well below the stream channel in this upland catchment; hence weathering depth is not controlled by the stream level within the catchment and not all of the water in the watershed is discharged to the stream.« less

Probing the deep critical zone beneath the Luquillo Experimental Forest, Puerto Rico

USGS Publications Warehouse

Buss, Heather L.; Brantley, Susan L.; Scatena, Fred; Bazilevskaya, Katya; Blum, Alex E.; Schulz, Marjorie S.; Jiménez, Rafael; White, Arthur F.; Rother, G.; Cole, D.

2013-01-01

Recent work has suggested that weathering processes occurring in the subsurface produce the majority of silicate weathering products discharged to the world's oceans, thereby exerting a primary control on global temperature via the well-known positive feedback between silicate weathering and CO2. In addition, chemical and physical weathering processes deep within the critical zone create aquifers and control groundwater chemistry, watershed geometry and regolith formation rates. Despite this, most weathering studies are restricted to the shallow critical zone (e.g. soils, outcrops). Here we investigate the chemical weathering, fracturing and geomorphology of the deep critical zone in the Bisley watershed in the Luquillo Critical Zone Observatory, Puerto Rico, from two boreholes drilled to 37.2 and 27.0 m depth, from which continuous core samples were taken. Corestones exposed aboveground were also sampled. Weathered rinds developed on exposed corestones and along fracture surfaces on subsurface rocks slough off of exposed corestones once rinds attain a thickness up to ~1 cm, preventing the corestones from rounding due to diffusion limitation. Such corestones at the land surface are assumed to be what remains after exhumation of similar, fractured bedrock pieces that were observed in the drilled cores between thick layers of regolith. Some of these subsurface corestones are massive and others are highly fractured, whereas aboveground corestones are generally massive with little to no apparent fracturing. Subsurface corestones are larger and less fractured in the borehole drilled on a road where it crosses a ridge compared with the borehole drilled where the road crosses the stream channel. Both borehole profiles indicate that the weathering zone extends to well below the stream channel in this upland catchment; hence weathering depth is not controlled by the stream level within the catchment and not all of the water in the watershed is discharged to the stream

Employing 2D Forward Modeling of Gravity and Magnetic Data to Further Constrain the Magnitude of Extension Recorded by the Caetano Caldera, Nevada

NASA Astrophysics Data System (ADS)

Ritzinger, B. T.; Glen, J. M. G.; Athens, N. D.; Denton, K. M.; Bouligand, C.

2015-12-01

Regionally continuous Cenozoic rocks in the Basin and Range that predate the onset of major mid-Miocene extension provide valuable insight into the sequence of faulting and magnitude of extension. An exceptional example of this is Caetano caldera, located in north-central Nevada, that formed during the eruption of the Caetano Tuff at the Eocene-Oligocene transition. The caldera and associated deposits, as well as conformable caldera-filling sedimentary and volcanic units allow for the reconstruction of post Oligocene extensional faulting. Extensive mapping and geochronologic, geochemical and paleomagnetic analyses have been conducted over the last decade to help further constrain the eruptive and extensional history of the Caetano caldera and associated deposits. Gravity and magnetic data, that highlight contrasts in density and magnetic properties (susceptibility and remanence), respectively, are useful for mapping and modeling structural and lithic discontinuities. By combining existing gravity and aeromagnetic data with newly collected high-resolution gravity data, we are performing detailed potential field modeling to better characterize the subsurface within and surrounding the caldera. Modeling is constrained by published geologic map and cross sections and by new rock properties for these units determined from oriented drill core and hand samples collected from outcrops that span all of the major rock units in the study area. These models will enable us to better map the margins of the caldera and more accurately determine subsurface lithic boundaries and complex fault geometries, as well as aid in refining estimates of the magnitude of extension across the caldera. This work highlights the value in combining geologic and geophysical data to build an integrated structural model to help characterize the subsurface and better constrain the extensional tectonic history if this part of the Great Basin.

Three-phase heaters with common overburden sections for heating subsurface formations

DOEpatents

Vinegar, Harold J [Bellaire, TX

2012-02-14

A heating system for a subsurface formation is described. The heating system includes three substantially u-shaped heaters with first end portions of the heaters being electrically coupled to a single, three-phase wye transformer and second end portions of the heaters being electrically coupled to each other and/or to ground. The three heaters may enter the formation through a first common wellbore and exit the formation through a second common wellbore so that the magnetic fields of the three heaters at least partially cancel out in the common wellbores.

Sorting Out the Ocean Crust Deep Biosphere with Single Cell Omics Approaches

NASA Astrophysics Data System (ADS)

Orcutt, B.; D'Angelo, T.; Goordial, J.; Jones, R. M.; Carr, S. A.

2017-12-01

Although oceanic crust comprises a large habitat for subsurface life, the structure, function, and dynamics of microbial communities living on rocks in the subsurface are poorly understood. Single cell level approaches can overcome limitations of low biomass in subsurface systems. Coupled with incubation experiments with amino acid orthologs, single cell level sorting can reveal high resolution information about identity, functional potential, and growth. Leveraging collaboration with the Single Cell Genomics Center and the Facility for Aquatic Cytometry at Bigelow Laboratory, we present recent results from single cell level sorting and -omics sequencing from several crustal environments, including the Atlantis Massif and the Juan de Fuca Ridge flank. We will also highlight new experiments conducted with samples recovered from the flank of the Mid-Atlantic Ridge.

Roles of Nano- and Micro-Scale Subsurface Geochemical Reactions on Environmentally Sustainable Geologic Carbon Dioxide Sequestration

NASA Astrophysics Data System (ADS)

Hu, Yandi

Geologic CO2 sequestration (GCS) is a promising approach to reduce anthropogenic CO2 emissions into the atmosphere. At GCS sites, injected CO2 is kept in formation rock by an overlying low permeability caprock. During and after CO2 injection, geochemical reactions can affect the porosity, permeability, and pollutant transport in aquifers. Despite their importance, nano- and micro-scale subsurface geochemical reactions are far from well-understood. Clay mobilization has been reported to decrease aquifer permeability during water flooding, and clay minerals are abundant in caprock. Thus, we studied CO2-brine-clay interactions under varied conditions relevant to different GCS sites (at 35-95°C and under 35-120 atm CO2, in water, NaCl, MgCl2, or CaCl2 solutions). Biotite, Fe-bearing mica, was used as a model clay mineral. We observed numerous fibrous illite precipitates on mica after reaction for only 3 h, which had not been previously reported. A few hours later, the mica surface cracked and fibrous illite detached. The mobilization of fibrous illite can decrease the aquifer's permeability greatly and affect the safety and efficiency of GCS. Mechanisms related to ion exchange, mica swelling, and CO2 intercalation were explored. Oriented aggregation of illite nanoparticles forming the fibrous illite was directly observed, suggesting a new mechanism for fibrous illite formation. Interestingly, besides the pH effect, aqueous CO2 enhances mica cracking over N2. These findings can help to achieve safer subsurface operations. At GCS field sites, Fe concentration increased near the injection sites and originally adsorbed pollutants were released. As the brine flows, Fe re-precipitated because of pH increase. To better predict the fate and transport of aqueous pollutants, the nucleation and growth of Fe(III) (hydr)oxides were studied. New information about sizes and volumes of the Fe(III) (hydr)oxide nanoparticles precipitated in solution and on quartz, mica, and sapphire were provided using small angle X-ray scattering, in the presence of different ions (Al 3+, Cl-, NO3-, and SO 42-). Using complementary techniques, the controlling mechanisms related to surface charge, bond formation, and interfacial energies were explored. These new findings can help better predict pollutant transport in aquifers not only at GCS sites, but also in managed aquifer recharge and acid mine drainage sites.

Dissolution-Enlarged Fractures Imaging Using Electrical Resistivity Tomography (ERT)

NASA Astrophysics Data System (ADS)

Siami-Irdemoosa, Elnaz

In recent years the electrical imaging techniques have been largely applied to geotechnical and environmental investigations. These techniques have proven to be the best geophysical methods for site investigations in karst terrain, particularly when the overburden soil is clay-dominated. Karst is terrain with a special landscape and distinctive hydrological system developed by dissolution of rocks, particularly carbonate rocks such as limestone and dolomite, made by enlarging fractures into underground conduits that can enlarge into caverns, and in some cases collapse to form sinkholes. Bedding planes, joints, and faults are the principal structural guides for underground flow and dissolution in almost all karstified rocks. Despite the important role of fractures in karst development, the geometry of dissolution-enlarged fractures remain poorly unknown. These features are characterized by an strong contrast with the surrounding formations in terms of physical properties, such as electrical resistivity. Electrical resistivity tomography (ERT) was used as the primary geophysical tool to image the subsurface in a karst terrain in Greene County, Missouri. Pattern, orientation and density of the joint sets were interpreted from ERT data in the investigation site. The Multi-channel Analysis of Surface Wave (MASW) method and coring were employed to validate the interpretation results. Two sets of orthogonal visually prominent joints have been identified in the investigation site: north-south trending joint sets and west-east trending joint sets. However, most of the visually prominent joint sets are associated with either cultural features that concentrate runoff, natural surface drainage features or natural surface drainage.

The importance of bulk density determination in gravity data processing for structure interpretation

NASA Astrophysics Data System (ADS)

Wildan, D.; Akbar, A. M.; Novranza, K. M. S.; Sobirin, R.; Permadi, A. N.; Supriyanto

2017-07-01

Gravity method use rock density variation for determining subsurface lithology and geological structure. In the "green area" where measurement of rock density has not been done, an attemp to find density is usually performed by calculating using Parasnis method, or by using using the average of rock density in the earth's crust (2,67 gr/cm3) or by using theoritical value of dominant rock density in the survey area (2,90 gr/cm3). Those three values of densities are applied to gravity data analysis in the hilly "X" area. And we have compared all together in order to observed which value has represented the structure better. The result showed that the higher value of rock density, the more obvious structure in the Bouguer anomaly profile. It is due to the contrast of maximum and minimum value of Bouguer anomaly that will affect the exageration in distance vs Bouguer anomaly graphic.

The spatial distribution of rocks on Mars

NASA Astrophysics Data System (ADS)

Christensen, P. R.

1986-11-01

A Viking IR Thematic Mapper observations-based mapping of the spatial distribution of rocks exposed on the planet's surface exhibits a 6-percent areal coverage rock abundance. A model for the determination of rock abundance relates the thermal emission in each of the four Thematic Mapper bands to temperature contrasts in the field of view as well as to nonunit thermal emissivity due to absorption bands in the surface materials and the scattering of the outgoing energy by atmospheric dust and water ice; since each of these produces characteristic spectral and diurnal signatures, they can be readily separated. Dual-polarization radar measurements show the Tharsis volcanic region to be very rough, while thermal measurements indicate few rocks, accompanied by a dust covering. These observations suggest an approximately 1-km thick mantle of fines, overlying a rough subsurface, on which both erosional and depositional aeolian processes have exerted considerable influence.

Radar Imaging of Europa's Subsurface Properties and Processes: The View from Earth

NASA Astrophysics Data System (ADS)

Blankenship, D. D.; Moore, W. B.; Young, D. A.; Peters, M. E.

2007-12-01

A primary objective of future Europa studies will be to characterize the distribution of shallow subsurface water as well as to identify any ice-ocean interface. Another objective will be to understand the formation of surface and subsurface features associated with interchange processes between any ocean and the surface. Achieving these objectives will require either direct or inferred knowledge of the position of any ice/water interfaces as well as any brine or layer pockets. We will review the hypothesized processes that control the thermal, compositional and structural (TCS) properties, and therefore the dielectric character, of the subsurface of Europa's icy shell. Our approach will be to extract the TCS properties for various subsurface processes thought to control the formation of major surface (e.g., ridges/bands, lenticulae, chaos, cratering...) and subsurface (e.g., rigid shell eutectics, diapirs, accretionary lenses ...) features on Europa. We will then assess the spectrum of analog processes and TCS properties represented by Earth's cryosphere including both Arctic and Antarctic ice sheets, ice shelves and valley glaciers. There are few complete analogs over the full TCS space but, because of the wide range of ice thickness, impurities and strain rates for Earth's cryosphere, there are many more analogs than many Earth and planetary researchers might imagine for significant portions of this space (e.g., bottom crevasses, marine ice shelf/subglacial lake accretion, surging polythermal glaciers...).Our ultimate objective is to use these Earth analog studies to define the radar imaging approach for Europa's subsurface that will be most useful for supporting/refuting the hypotheses for the formation of major surface/subsurface features as well as for "pure" exploration of Europa's icy shell and its interface with the underlying ocean.

Carbon Sequestration in Unconventional Reservoirs: Advantages and Limitations

NASA Astrophysics Data System (ADS)

Zakharova, N. V.; Slagle, A. L.; Goldberg, D.

2014-12-01

To make a significant impact on anthropogenic CO2 emissions, geologic carbon sequestration would require thousands of CO2 repositories around the world. Unconventional reservoirs, such as igneous rocks and fractured formations, may add substantial storage capacity and diversify CO2 storage options. In particular, basaltic rocks represent a promising target due to their widespread occurrence, potentially suitable reservoir structure and high reactivity with CO2, but a comprehensive evaluation of worldwide CO2 sequestration capacity in unconventional reservoirs is lacking. In this presentation we summarize available data on storage potential of basaltic rocks and fractured formations illustrated by field examples from the Columbia River Basalt, the Newark Rift Basin and IODP Site 1256, and discuss potential limiting factors, such as effective porosity and the risk of inducing earthquakes by CO2 injections. Large Igneous Provinces (LIPs), low-volume flows and intrusions, and ocean floor basalt represent three general classes of basaltic reservoirs, each characterized by different structure and storage capacity. Oceanic plateaus and LIPs are projected to have the highest CO2 storage capacity, on the order of thousands gigatons (Gt) per site, followed by continental LIPs and ocean floor basalts (hundreds to thousands Gt per site). Isolated basalt flows and intrusions are likely to offer only low- to moderate-capacity options. An important limiting factor on CO2 injection volumes and rates is the risk of inducing earthquakes by increasing pore pressure in the subsurface. On continents, available in situ stress analysis suggests that local stress perturbations at depth may create relaxed stress conditions, allowing for pore pressure increase without reactivating fractures and faults. Remote storage sites on oceanic plateaus and below the seafloor are advantageous due to low impact of potential seismic and/or leakage events. Other effects, such as thermal stresses created by temperature difference between injected fluid and the host formation, may be particularly important for reservoir stability in high-temperature offshore locations. Overall, unconventional reservoirs in offshore locations offer the potential benefits of vast and safe storage for captured CO2 emissions.

IODP/ICDP Expedition 364-Drilling the Cretaceous-Paleogene Chicxulub impact crater: Insights into large craters formation and their effect on life.

NASA Astrophysics Data System (ADS)

Gulick, S. P. S.; Morgan, J. V.; Fucugauchi, J. U.; Bralower, T. J.; Chenot, É.; Christeson, G. L.; Claeys, P.; Cockell, C. S.; Collins, G. S.; Coolen, M.; Gebhardt, C.; Goto, K.; Kring, D. A.; Xiao, L.; Lowery, C.; Mellett, C.; Ocampo-Torres, R.; Osinski, G. R.; Perez-Cruz, L. L.; Pickersgill, A.; Poelchau, M.; Rae, A.; Rasmussen, C.; Rebolledo-Vieyra, M.; Riller, U. P.; Sato, H.; Schmitt, D. R.; Smit, J.; Tikoo, S.; Tomioka, N.; Whalen, M. T.; Zylberman, W.; Jones, H.; Gareth, C.; Wittmann, A.; Lofi, J.; Yamaguchi, K. E.; Ferrière, L.

2016-12-01

An international project to drill the Chicxulub impact crater was conducted in April and May, 2016 as Expedition 364 of the International Ocean Discovery Program (IODP) and International Continental Scientific Drilling Project (ICDP). Site M0077 is located offshore Yucatan in the southern Gulf of Mexico. The target was to core the only pristine terrestrial peak ring and to measure physical properties of the entire borehole. Specific questions included: What rocks comprise a topographic peak ring? How are peak rings formed? How are rocks weakened during large impacts to allow them to collapse and form relatively wide, flat craters? What insights arise from biologic recovery in the Paleogene within a potentially "toxic" ocean basin? Are impact craters (including peak rings) habitats for life? Coring occurred from 503 - 1334.7 mbsf with nearly 100% recovery. Wireline logs were collected from ultra slimline tools to total depth including gamma ray, magnetic susceptibility, sonic, borehole fluid temperature and conductivity, resistivity data, borehole images, and a finely spaced vertical seismic profile. Stratigraphy cored included 110 m of Eocene and Paleocene carbonates, 130 m of allochthonous impactites, and 590 m of crustal basement with dikes. All cores were measured using a shipboard core logger (density, gamma ray, magnetic susceptibility and resistivity) and shorebased dual energy, 0.3 mm resolution CT scanner. These data allow us to: 1) refine numerical models of the formation of the Chicxulub impact structure; 2) place constraints on environmental perturbations that led to the K-Pg mass extinction; 3) improve simulations of impact craters on other planetary bodies; 4) examine deformation mechanisms for insights into how rocks weaken during impacts; 5) study impact generated hydrothermal systems and 6) understand the effects of impacts on the deep biosphere including as a habitat for microbial life with implications for evolution on Earth and astrobiology. Key results are that the Chicxulub peak ring is formed from fractured basement rocks that may host a subsurface biosphere. The impactite layer overlying the peak ring in turn provides insight into resurge and tsunami processes, while the Paleogene sediments contain the record of the recovery of life after the mass extinction event.

Porosity evolution of upper Miocene reefs, Almeria Province, southern Spain

USGS Publications Warehouse

Armstrong, A.K.; Snavely, P.D.; Addicott, W.O.

1980-01-01

Sea cliffs 40 km east of Almeria, southeastern Spain, expose upper Miocene reefs and patch reefs of the Plomo formation. These reefs are formed of scleractinian corals, calcareous algae, and mollusks. The reef cores are as much as 65 m thick and several hundred meters wide. Fore-reef talus beds extend 1,300 m across and are 40 m thick. The reefs and reef breccias are composed of calcific dolomite. They lie on volcanic rocks that have a K-Ar date of 11.5 m.y. and in turn are overlain by the upper Miocene Vicar Formation. In the reef cores and fore-reef breccia beds, porosity is both primary and postdepositional. Primary porosity is of three types: (a) boring clam holes in the scleractinian coral heads, cemented reef rocks, and breccias; (b) intraparticle porosity within the corals, Halimeda plates, and vermetid worm tubes; and (c) interparticle porosity between bioclastic fragments and in the reef breccia. Postdepositional moldic porosity was formed by the solution of aragonitic material such as molluscan and coral fragments. The Plomo reef carbonate rocks have high porosity and permeability, and retain a great amount of depositional porosity. Pores range in size from a few micrometers to 30 cm. The extensive intercrystalline porosity and high permeability resulted from dolomitization of micritic matrix. Dolomite rhombs are between 10 and 30 μ across. More moldic porosity was formed by the dissolution of the calclte bioclasts. Some porosity reduction has occurred by incomplete and partial sparry calcite infilling of interparticular, moldic, and intercrystalline voids. The high porosity and permeability of these reefs make them important targets for petroleum exploration in the western Mediterranean off southern Spain. In these offshore areas in the subsurface the volcanic ridge and the Plomo reef complex are locally onlapped or overlapped by 350 m or more of Miocene(?) and Pliocene fine-grained sedimentary rocks. The possibility exists that the buried Plomo reef deposits may form traps for oil and gas in the offshore areas southwest of the type locality. Stratigraphic traps also may occur where the Neogene sequence above the Plomo reef complex onlaps the volcanic ridge.

Microbial monitoring during CO2 storage in deep subsurface saline aquifers in Ketzin, Germany

NASA Astrophysics Data System (ADS)

Wuerdemann, H.; Wandrey, M.; Fischer, S.; Zemke, K.; Let, D.; Zettlitzer, M.; Morozova, D.

2010-12-01

Investigations on subsurface saline aquifers have shown an active biosphere composed of diverse groups of microorganisms in the subsurface. Since microorganisms represent very effective geochemical catalysts, they may influence the process of CO2 storage significantly. In the frames of the EU Project CO2SINK a field laboratory to study CO2 storage into saline aquifer was operated. Our studies aim at monitoring of biological and biogeochemical processes and their impact on the technical effectiveness of CO2 storage technique. The interactions between microorganisms and the minerals of both the reservoir and the cap rock may cause changes to the structure and chemical composition of the rock formations, which may influence the reservoir permeability locally. In addition, precipitation and corrosion may be induced around the well affecting the casing and the casing cement. Therefore, analyses of the composition of microbial communities and its changes should contribute to an evaluation of the effectiveness and reliability of the long-term CO2 storage technique. In order to investigate processes in the deep biosphere caused by the injection of supercritical CO2, genetic fingerprinting (PCR SSCP Single-Strand-Conformation Polymorphism) and FISH (Fluorescence in situ Hybridisation) were used for identification and quantification of microorganisms. Although saline aquifers could be characterised as an extreme habitat for microorganisms due to reduced conditions, high pressure and salinity, a high number of diverse groups of microorganisms were detected with downhole sampling in the injection and observation wells at a depth of about 650m depth. Of great importance was the identification of the sulphate reducing bacteria, which are known to be involved in corrosion processes. Microbial monitoring during CO2 injection has shown that both quantity and diversity of microbial communities were strongly influenced by the CO2 injection. In addition, the indigenous microbial communities revealed a high adaptability to the changed environments after CO2 injection. In order to investigate processes in the rock substrate, long term CO2 exposure experiments on freshly drilled, pristine Ketzin reservoir core samples were accomplished for 24 months using sterile synthetic brine under in situ pressure and temperature conditions. The composition of the microbial community dominated by chemoorganotrophic bacteria and hydrogen oxidizing bacteria changed slightly under CO2 exposure. In addition, changes in porosities were observed with time. During the experiments porosity first increased due to mineral dissolution but then tend to decrease due to mineral precipitation. These mineralogical changes are consistent with changes in fluid composition during the course of the experiments that indicate notably increased K+, Ca2+, Mg2+, and SO4 2- concentrations. K+, Ca2+, Mg2+ concentrations exceeded the reservoir brine composition significantly and can be attributed to the CO2 exposure.

Authigenic carbon entombed in methane-soaked sediments from the northeastern transform margin of the Guaymas Basin, Gulf of California

NASA Astrophysics Data System (ADS)

Paull, Charles K.; Ussler, William; Peltzer, Edward T.; Brewer, Peter G.; Keaten, Rendy; Mitts, Patrick J.; Nealon, Jeffrey W.; Greinert, Jens; Herguera, Juan-Carlos; Elena Perez, M.

2007-06-01

Extensive ROV-based sampling and exploration of the seafloor was conducted along an eroded transform-parallel fault scarp on the northeastern side of the Guaymas Basin in the Gulf of California to observe the nature of fluids venting from the seafloor, measure the record left by methane-venting on the carbonates from this area, and determine the association with gas hydrate. One gas vent vigorous enough to generate a water-column gas plume traceable for over 800 m above the seafloor was found to emanate from a ˜10-cm-wide orifice on the eroded scarp face. Sediment temperature measurements and topography on a sub-bottom reflector recorded in a transform-parallel seismic reflection profile identified a subsurface thermal anomaly beneath the gas vent. Active chemosynthetic biological communities (CBCs) and extensive authigenic carbonates that coalesce into distinct chemoherm structures were encountered elsewhere along the eroded transform-parallel scarp. The carbon isotopic composition of methane bubbles flowing vigorously from the gas vent (-53.6±0.8‰ PDB) is comparable to methane found in sediment cores taken within the CBCs distributed along the scarp (-51.9±8.1‰ PDB). However, the δ13C value of the CO 2 in the vent gas (+12.4±1.1‰ PDB) is very distinct from those for dissolved inorganic carbon (DIC) (-35.8‰ to -2.9‰ PDB) found elsewhere along the scarp, including underneath CBCs. The δ13C values of the carbonate-rich sediments and rocks exposed on the seafloor today also span an unusually large range (-40.9‰ to +12.9‰ PDB) and suggest two distinct populations of authigenic carbonate materials were sampled. Unconsolidated sediments and some carbonate rocks, which have lithologic evidence for near-seafloor formation, have negative δ13C values, while carbonate rocks that clearly formed in the subsurface have positive δ13C values (up to +23.0‰) close to that measured for CO 2 in the vent gas. There appears to be two carbon sources for the authigenic carbonates: (1) deeply-sourced, isotopically heavy CO 2 (˜+12‰); and (2) isotopically light DIC derived from local anaerobic oxidation of methane at the sulfate-methane interface in the shallow subsurface. Addition of isotopically light methane-derived carbon at the seafloor may completely mask the isotopically heavy CO 2 signature (+12.4‰) in the underlying sediments. Thus, the authigenic carbonates may have formed from the same methane- and carbon dioxide-bearing fluid, but under different migration and alteration conditions, depending on how it migrated through the sediment column.

Near-field non-radial motion generation from underground chemical explosions in jointed granite

NASA Astrophysics Data System (ADS)

Vorobiev, Oleg; Ezzedine, Souheil; Hurley, Ryan

2018-01-01

This paper describes analysis of non-radial ground motion generated by chemical explosions in a jointed rock formation during the Source Physics Experiment (SPE). Such motion makes it difficult to discriminate between various subsurface events such as explosions, implosions (i.e. mine collapse) and earthquakes. We apply 3-D numerical simulations to understand experimental data collected during the SPEs. The joints are modelled explicitly as compliant thin inclusions embedded into the rock mass. Mechanical properties of the rock and the joints as well as the joint spacing and orientation are inferred from experimental test data, and geophysical and geological characterization of the SPE site which is dominantly Climax Stock granitic outcrop. The role of various factors characterizing the joints such as joint spacing, frictional properties, orientation and persistence in generation of non-radial motion is addressed. The joints in granite at the SPE site are oriented in nearly orthogonal directions with two vertical sets dipping at 70-80 degrees with the same strike angle, one vertical set almost orthogonal to the first two and one shallow angle joint set dipping 15 degrees. In this study we establish the relationship between the joint orientation and azimuthal variations in the polarity of the observed shear motion. The majority of the shear motion is generated due to the effects of non-elastic sliding on the joints near the source, where the wave can create significant shear stress to overcome the cohesive forces at the joints. Near the surface the joints are less confined and are subject to sliding when the pressure waves are reflected. In the far field, where the cohesive forces on the joints cannot be overcome, additional shear motion can be generated due to elastic anisotropy of the rock mass given by preferred spatial orientations of compliant joints.

Magnetotelluric Investigations in Tuwa-Godhra Region, Gujarat (India)

NASA Astrophysics Data System (ADS)

Mohan, Kapil; Chaudhary, Peush; Kumar, G. Pavan; Kothyari, Girish Ch.; Choudhary, Virender; Nagar, Mehul; Patel, Pruthul; Gandhi, Drasti; Kushwaha, Dilip; Rastogi, B. K.

2018-05-01

Magnetotelluric (MT) data have been acquired at 40 locations in Tuwa and its surrounding region (200 km east of Ahmedabad and 15 km north-northwest of Godhra) in the Mainland Gujarat with an average station spacing of 1.5 km. MT impedance tensors have been estimated in the period range of 0.001-100 s. The data have been modeled using non-linear conjugate gradient scheme taking both apparent resistivity and phase into account. From the 2D models of the MT data, the weathered granite with Quaternary sediments (with resistivity of < 700 Ω m) have been inferred up to a depth of 500 m followed by Godhra granite (having resistivity up to 105 Ω m) with a thickness 6.5 km. The Aravalli supergroup has been inferred below Godhra granite. The Lunavada group of rocks have been inferred in the eastern part of the study area (having resistivity value ranging from 103 to 104 Ω m) separated from the Godhra granite by a contact zone. The comparatively very low-resistivity rocks (< 400 Ω m) of Udaipur formation followed by Paleoproterozoic carbonate rocks with fluid have been inferred below 8-10 km depth. The percolation of water from the surface through the contact zone of Lunavada and Champaner groups has been suggested. The presence of hot water springs in 10 km SW from the center of the study area (at the contact zone of Godhra granite and basalt) might be due to the western trending lithostratigraphic slope, hydrostatic pressure generated due to heat produced from interaction of water with the carbonate rocks at deeper depth and high subsurface temperature due to high geothermal gradient. The segmented nature of Himmatnagar Fault (HnF) is identified in the central portion of the study area.

Anisotropy of permeability of reservoir rocks over Miaoli area, NW Taiwan.

NASA Astrophysics Data System (ADS)

Bo-Siang, Xiong; Loung-Yie, Tsai

2013-04-01

The amount of the CO2 has risen since the Industrial Evolution. In order to reduce the amount of CO2 in atmosphere, CO2 sequestration is considered to be the most effective way. In recent years, research about subsurface storage of CO2 into geological formations has increased rapidly. Assessment of storage capability is needed before selecting a site for sequestration. Porosity and permeability are important assessment factors for CO2 sequestration in reservoir rocks. In order to improve the assessment, reservoir rock properties are important and need to be evaluated in advance. Porosity of sandstone is controlled by texture and degree of cementation, whereas permeability is controlled by pore-throat size, pore types and connectivity of pore throat. Sandstones of Miocene to Pleistocene in Miaoli area, NW Taiwan, were collected in this study. YOKO2 porosity/permeability detector is used to measure their permeability perpendicular and parallel to bedding planes under 3 to 60MPa confining pressure with Helium as media. Optical microscope and scanning electron microscope (SEM) were then used to observe the mineral composition, lithology, texture and pore type of sandstones, so as to explore the influence of rock properties on porosity and anisotropy of permeability, as well as the storage potential for CO2 sequestration in the future. The experimental results show that most of the horizontal permeability exceeds the vertical permeability and the anisotropy increases with increasing confining pressure. Mineral composition of sandstones studied were mainly quartz and lithic with little feldspar content. The pore types were mainly primary pores and micropores in this study. The correlation between quantity of macropores and permeability were higher than total porosity and permeability, mainly due to total porosity contains micropores which contribute little to permeability.

Modeling deformation processes of salt caverns for gas storage due to fluctuating operation pressures

NASA Astrophysics Data System (ADS)

Böttcher, N.; Nagel, T.; Goerke, U.; Khaledi, K.; Lins, Y.; König, D.; Schanz, T.; Köhn, D.; Attia, S.; Rabbel, W.; Bauer, S.; Kolditz, O.

2013-12-01

In the course of the Energy Transition in Germany, the focus of the country's energy sources is shifting from fossil to renewable and sustainable energy carriers. Since renewable energy sources, such as wind and solar power, are subjected to annual, seasonal, and diurnal fluctuations, the development and extension of energy storage capacities is a priority in German R&D programs. Common methods of energy storage are the utilization of subsurface caverns as a reservoir for natural or artificial fuel gases, such as hydrogen, methane, or the storage of compressed air. The construction of caverns in salt rock is inexpensive in comparison to solid rock formations due to the possibility of solution mining. Another advantage of evaporite as a host material is the self-healing capacity of salt rock. Gas caverns are capable of short-term energy storage (hours to days), so the operating pressures inside the caverns are fluctuating periodically with a high number of cycles. This work investigates the influence of fluctuating operation pressures on the stability of the host rock of gas storage caverns utilizing numerical models. Therefore, we developed a coupled Thermo-Hydro-Mechanical (THM) model based on the finite element method utilizing the open-source software platform OpenGeoSys. Our simulations include the thermodynamic behaviour of the gas during the loading/ unloading of the cavern. This provides information on the transient pressure and temperature distribution on the cavern boundary to calculate the deformation of its geometry. Non-linear material models are used for the mechanical analysis, which describe the creep and self-healing behavior of the salt rock under fluctuating loading pressures. In order to identify the necessary material parameters, we perform experimental studies on the mechanical behaviour of salt rock under varying pressure and temperature conditions. Based on the numerical results, we further derive concepts for monitoring THM quantities in the vicinity of the cavern. These programs will allow detecting changes of the host rock properties during the construction and operation of the storage facility. The developed model will be used by public authorities for land use planning issues.

Fracturing of doleritic intrusions and associated contact zones: Implications for fluid flow in volcanic basins

NASA Astrophysics Data System (ADS)

Senger, Kim; Buckley, Simon J.; Chevallier, Luc; Fagereng, Åke; Galland, Olivier; Kurz, Tobias H.; Ogata, Kei; Planke, Sverre; Tveranger, Jan

2015-02-01

Igneous intrusions act as both carriers and barriers to subsurface fluid flow and are therefore expected to significantly influence the distribution and migration of groundwater and hydrocarbons in volcanic basins. Given the low matrix permeability of igneous rocks, the effective permeability in- and around intrusions is intimately linked to the characteristics of their associated fracture networks. Natural fracturing is caused by numerous processes including magma cooling, thermal contraction, magma emplacement and mechanical disturbance of the host rock. Fracturing may be locally enhanced along intrusion-host rock interfaces, at dyke-sill junctions, or at the base of curving sills, thereby potentially enhancing permeability associated with these features. In order to improve our understanding of fractures associated with intrusive bodies emplaced in sedimentary host rocks, we have investigated a series of outcrops from the Karoo Basin of the Eastern Cape province of South Africa, where the siliciclastic Burgersdorp Formation has been intruded by various intrusions (thin dykes, mid-sized sheet intrusions and thick sills) belonging to the Karoo dolerite. We present a quantified analysis of fracturing in- and around these igneous intrusions based on five outcrops at three individual study sites, utilizing a combination of field data, high-resolution lidar virtual outcrop models and image processing. Our results show a significant difference between the three sites in terms of fracture orientation. The observed differences can be attributed to contrasting intrusion geometries, outcrop geometry (for lidar data) and tectonic setting. Two main fracture sets were identified in the dolerite at two of the sites, oriented parallel and perpendicular to the contact respectively. Fracture spacing was consistent between the three sites, and exhibits a higher degree of variation in the dolerites compared to the host rock. At one of the study sites, fracture frequency in the surrounding host rock increases slightly toward the intrusion at approximately 3 m from the contact. We conclude by presenting a conceptual fluid flow model, showing permeability enhancement and a high potential for fluid flow-channeling along the intrusion-host rock interfaces.

Incorporating the Impacts of Small Scale Rock Heterogeneity into Models of Flow and Trapping in Target UK CO2 Storage Systems

NASA Astrophysics Data System (ADS)

Jackson, S. J.; Reynolds, C.; Krevor, S. C.

2017-12-01

Predictions of the flow behaviour and storage capacity of CO2 in subsurface reservoirs are dependent on accurate modelling of multiphase flow and trapping. A number of studies have shown that small scale rock heterogeneities have a significant impact on CO2flow propagating to larger scales. The need to simulate flow in heterogeneous reservoir systems has led to the development of numerical upscaling techniques which are widely used in industry. Less well understood, however, is the best approach for incorporating laboratory characterisations of small scale heterogeneities into models. At small scales, heterogeneity in the capillary pressure characteristic function becomes significant. We present a digital rock workflow that combines core flood experiments with numerical simulations to characterise sub-core scale capillary pressure heterogeneities within rock cores from several target UK storage reservoirs - the Bunter, Captain and Ormskirk sandstone formations. Measured intrinsic properties (permeability, capillary pressure, relative permeability) and 3D saturations maps from steady-state core flood experiments were the primary inputs to construct a 3D digital rock model in CMG IMEX. We used vertical end-point scaling to iteratively update the voxel by voxel capillary pressure curves from the average MICP curve; with each iteration more closely predicting the experimental saturations and pressure drops. Once characterised, the digital rock cores were used to predict equivalent flow functions, such as relative permeability and residual trapping, across the range of flow conditions estimated to prevail in the CO2 storage reservoirs. In the case of the Captain sandstone, rock cores were characterised across an entire 100m vertical transect of the reservoir. This allowed analysis of the upscaled impact of small scale heterogeneity on flow and trapping. Figure 1 shows the varying degree to which heterogeneity impacted flow depending on the capillary number in the Captain sandstone. At low capillary numbers, typical of regions where flow is dominated by buoyancy, fluid flow is impeded and trapping enhanced. At high capillary numbers, typical of the near wellbore environment, the fluid distributed homogeneously and the equivalent relative permeability was higher leading to improved injectivity.

Metagenomic identification of active methanogens and methanotrophs in serpentinite springs of the Voltri Massif, Italy

PubMed Central

Thornton, Christopher N.; Hyer, Alex; Twing, Katrina I.; Longino, August A.; Lang, Susan Q.; Lilley, Marvin D.; Früh-Green, Gretchen L.; Schrenk, Matthew O.

2017-01-01

The production of hydrogen and methane by geochemical reactions associated with the serpentinization of ultramafic rocks can potentially support subsurface microbial ecosystems independent of the photosynthetic biosphere. Methanogenic and methanotrophic microorganisms are abundant in marine hydrothermal systems heavily influenced by serpentinization, but evidence for methane-cycling archaea and bacteria in continental serpentinite springs has been limited. This report provides metagenomic and experimental evidence for active methanogenesis and methanotrophy by microbial communities in serpentinite springs of the Voltri Massif, Italy. Methanogens belonging to family Methanobacteriaceae and methanotrophic bacteria belonging to family Methylococcaceae were heavily enriched in three ultrabasic springs (pH 12). Metagenomic data also suggest the potential for hydrogen oxidation, hydrogen production, carbon fixation, fermentation, and organic acid metabolism in the ultrabasic springs. The predicted metabolic capabilities are consistent with an active subsurface ecosystem supported by energy and carbon liberated by geochemical reactions within the serpentinite rocks of the Voltri Massif. PMID:28149702

Growing Pebbles and Conceptual Prisms - Understanding the Source of Student Misconceptions about Rock Formation.

ERIC Educational Resources Information Center

Kusnick, Judi

2002-01-01

Analyzes narrative essays--stories of rock formation--written by pre-service elementary school teachers. Reports startling misconceptions among preservice teachers on pebbles that grow, human involvement in rock formation, and sedimentary rocks forming as puddles as dry up, even though these students had completed a college level course on Earth…

Stratigraphy of Slick Rock district and vicinity, San Miguel and Dolores Counties, Colorado

USGS Publications Warehouse

Shawe, Daniel R.; Simmons, George C.; Archbold, Norbert L.

1968-01-01

The Slick Rock district covers about 570 square miles in western San Miguel and Dolores Counties, in southwestern Colorado. It is at the south edge of the salt-anticline region of southwestern Colorado and southeastern Utah and of the Uravan mineral belt.Deposition of Paleozoic sedimentary rocks in the district and vicinity was principally controlled by development of the Paradox Basin, and of Mesozoic rocks by development of a depositional basin farther west. The Paleozoic rocks generally are thickest at the northeast side of the Paradox Basin in a northwest- trending trough which seems to be a wide graben in Precambrian igneous and metamorphic basement rocks; Mesozoic rocks generally thicken westward and southwestward from the district.Sedimentary rocks rest on a Precambrian basement consisting of a variety of rocks, including granite and amphibolite. The surface of the Precambrian rocks is irregular and generally more than 2,000 feet below sea level and 7,000-11,000 feet below the ground surface. In the northern part of the district the Precambrian surface plunges abruptly northeastward into the trough occupying the northeast side of the Paradox Basin, and in the southern part it sags in a narrow northeasterly oriented trough. Deepening of both troughs, or crustal deformation in their vicinity, influenced sedimentation during much of late Paleozoic and Mesozoic time.The maximum total thickness of sedimentary rocks underlying the district is 13,000 feet, and prior to extensive erosion in the late Tertiary and the Quaternary it may have been as much as about 18,000 feet. The lower 5,000 feet or more of the sequence of sedimentary rocks consists of arenaceous strata of early Paleozoic age overlain by dominantly marine carbonate rocks and evaporite beds interbedded with lesser amounts of clastic sediments of late Paleozoic age. Overlying these rocks is about 4,500 feet of terrestrial clastic sediments, dominantly sandstone with lesser amounts of shale, mudstone, siltstone, and conglomerate, of late Paleozoic and Mesozoic age. Above these rocks is as much as 2,300 feet of marine shale of late Mesozoic age. Perhaps about 5,000 feet of clastic sedimentary rocks, dominantly sandstone and in part shale, of late Mesozoic and early Cenozoic age, overlay the older rocks of the district prior to late Cenozoic erosion...Outside the Slick Rock district the Mancos Shale is overlain by dominantly terrestrial sandstone, mudstone, and coaly beds of the Mesaverde Group of Late Cretaceous age, and younger units such as the Wasatch and Green River Formations of Tertiary age, which once may have extended across the district. These units, totaling possibly 5,000 feet in thickness, were removed by erosion following middle Tertiary uplift of the Colorado Plateau.Igneous rocks of Tertiary age crop out in only one small area in the district, but they are intruded extensively in the Mancos Shale east of the district, and, as shown by deep oil test wells, appear to be intruded widely in the Paradox Member of the Hermosa Formation in the southern part of the district and southeast of the district. Andesite porphyry occurs in a dike on Glade Mountain, microgranogabbro and microgranodiorite occur in thin sills east of the district, and rocks of similar composition form thick sills in the subsurface. All are similar chemically to igneous rocks in the San Juan Mountains southeast of the district and probably were the result of a specific igneous episode. They were intruded most likely during the Miocene.Surficial deposits of Quaternary age include glacial till, terrace gravels, alluvial fans, landslide debris, loess, other soil, alluvium, colluvium, and talus. On Glade Mountain, glacial till of probable early Pleistocene age merges westward with terrace gravels that are correlative with terrace gravels which lie on an old weathered surface of Mancos Shale farther west on the rim of the Dolores River Canyon.

43 CFR 3138.11 - How do I apply for a subsurface storage agreement?

Code of Federal Regulations, 2014 CFR

2014-10-01

... participation factor for all parties to the subsurface storage agreement; and (11) Supporting data (geologic maps showing the storage formation, reservoir data, etc.) demonstrating the capability of the reservoir... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false How do I apply for a subsurface storage...

43 CFR 3138.11 - How do I apply for a subsurface storage agreement?

Code of Federal Regulations, 2013 CFR

2013-10-01

... participation factor for all parties to the subsurface storage agreement; and (11) Supporting data (geologic maps showing the storage formation, reservoir data, etc.) demonstrating the capability of the reservoir... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false How do I apply for a subsurface storage...

43 CFR 3138.11 - How do I apply for a subsurface storage agreement?

Code of Federal Regulations, 2011 CFR

2011-10-01

... participation factor for all parties to the subsurface storage agreement; and (11) Supporting data (geologic maps showing the storage formation, reservoir data, etc.) demonstrating the capability of the reservoir... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false How do I apply for a subsurface storage...

43 CFR 3138.11 - How do I apply for a subsurface storage agreement?

Code of Federal Regulations, 2012 CFR

2012-10-01

... participation factor for all parties to the subsurface storage agreement; and (11) Supporting data (geologic maps showing the storage formation, reservoir data, etc.) demonstrating the capability of the reservoir... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false How do I apply for a subsurface storage...

Hydrovolcanism

NASA Technical Reports Server (NTRS)

Sheridan, M. F.; Wohletz, K. H.

1985-01-01

Hydrovolcanism is a common phenomena produced by the interaction of magma or magmatic heat with an external source of water, such as a surface body, an aquifer, or a glacier. The effects include hydrofracture of existing rock units in the subsurface and the formation of hyaloclastites in a subaqueous environment. Hydroexplosions originate within a few kilometers of the surface. They may be relatively small, phreatic events or devastating complex blasts. Large-scale experiments determined that the optimal mixing ratio of water to basaltic melt (thermite plus silicates) for efficient conversion of thermal energy into mechanical energy is in the range of 0.1 to 0.3. Based on experimental results, eruptions can be classified as dominantly magmatic if the ratio of external water to magma is less than 0.2. Eruptions with water/melt ratios in the range of 0.2 to 1.0 are highly explosive and carry tephra in a hot vapor that contains dominantly superheated (dry) steam.

Porosity and grain size controls on compaction band formation in Jurassic Navajo Sandstone

USGS Publications Warehouse

Schultz, Richard A.; Okubo, Chris H.; Fossen, Haakon

2010-01-01

Determining the rock properties that permit or impede the growth of compaction bands in sedimentary sequences is a critical problem of importance to studies of strain localization and characterization of subsurface geologic reservoirs. We determine the porosity and average grain size of a sequence of stratigraphic layers of Navajo Sandstone that are then used in a critical state model to infer plastic yield envelopes for the layers. Pure compaction bands are formed in layers having the largest average grain sizes (0.42–0.45 mm) and porosities (28%), and correspondingly the smallest values of critical pressure (-22 MPa) in the sequence. The results suggest that compaction bands formed in these layers after burial to -1.5 km depth in association with thrust faulting beneath the nearby East Kaibab monocline, and that hardening of the yield caps accompanied compactional deformation of the layers.

Fuzzy Logic Modelling and Hidden Geodynamic Parameters of Earth: What is the role of Fluid Pathaways and Hydrothermal Stages on the Mineralization Variations of Kozbudaklar Pluton over Southern Uludag

NASA Astrophysics Data System (ADS)

Kocaturk, Huseyin; Kumral, Mustafa

2016-04-01

Plate tectonics is one of the most illustrated theory and biggest geo-dynamic incident on earth surface and sub-surface for the earth science. Tectonic settlement, rock forming minerals, form of stratigraphy, ore genesis processes, crystal structures and even rock textures are all related with plate tectonic. One of the most known region of Turkey is Southern part of Uludaǧ and has been defined with three main lithological union. Region is formed with metamorphics, ophiolites and magmatic intrusions which are generally I-type granodiorites. Also these intrusion related rocks has formed and altered by high grade hydrothermal activity. This study approaches to understand bigger to smaller frameworks of these processes which between plate tectonics and fluid pathways. Geodynamic related fuzzy logic modelling is present us compact conclusion report about structural associations for the economic generations. Deformation structures and fluid pathways which related with plate tectonics progressed on our forearc system and each steps of dynamic movements of subducting mechanism has been seemed affect both hydrothermal stages and mineral variations together. Types of each deformation structure and mineral assemblages has characterized for flux estimations which can be useful for subsurface mapping. Geoanalytical results showed us clear characteristic stories for mutual processes. Determined compression and release directions on our map explains not only hydrothermal stages but also how succesion of intrusions changes. Our fuzzy logic models intersect sections of physical and chemical interactions of study field. Researched parameters like mafic minerals and enclave ratios on different deformation structures, cross sections of structures and relative existing sequence are all changes with different time periods like geochemical environment and each vein. With the combined informations in one scene we can transact mineralization processes about region which occurs in different stages such as subducting slabs, arc volcanism, subsurface flux estimates related orogenic processes, and other geochemical effects of plate movements. Keywords: Hydrothermal Stages, Flux Estimate, Southern Region of Uludaǧ, Subsurface Mapping

Some New Windows into Terrestrial Deep Subsurface Microbial Ecosystems

NASA Astrophysics Data System (ADS)

Moser, D. P.

2011-12-01

Over the past several years, our group has surveyed the microbial ecology and biogeochemistry of a range of fracture rock subsurface ecosystems via deep mine boreholes in South Africa, the United States, and Canada; and boreholes from surface or deeply-sourced natural springs of the U.S. Great Basin. Collectively, these mostly unexplored habitats represent a wide range of geologic provinces, host rock types, aquatic chemistries, and the vast potential for biogeographic isolation. Thus, patterns of microbial diversity are of interest from the perspective of filling a fundamental knowledge gap; and while not necessarily expected, the detection of closely related microorganisms from geographically isolated settings would be noteworthy. Across these sample sets, microbial communities were invariably very low in biomass (e.g. 10e3 - 10e4 cells per mL) and dominated by deeply-branching bacterial lineages, particularly from the phyla Firmicutes and Nitrospira. In several cases, the Firmicutes have shown very close phylogenetic affiliations to lineages detected at divergent locations. For example, one abundant lineage from a new artesian well drilled into the Furnace Creek Fault of Death Valley, CA bears a very close phylogenetic relatedness to environmental DNA sequences (SSU rRNA gene) detected in one of the world's deepest mines (Tau Tona of South Africa) and what was North America's deepest gold mine (Homestake of South Dakota). Several radioactive wells from the Nevada National Security Site have produced rRNA gene sequences very close (e.g. greater than 99% identity) to that of Desulforudis audaxviator, a rarely detected microorganism thought to subsist as a single species ecosystem on the products of radiochemical reactions in deep crustal rocks from the South African Witwatersrand Basin. These sequences, along with more distantly related sequences from the marine subsurface (ridge flank basalt and mud volcanoes) and groundwater in Europe, hint at a role in certain hydrogen-rich subsurface settings for this group. Likewise, patterns of archaeal diversity across many of our Great Basin sites suggest shared deep lineages, particularly with the phylum, Thaumarchaeota. Here we will explore the possible significance of these patterns of diversity and discuss future research plans involving high throughput molecular techniques.

Assessing the Potential for Ancient Habitable Environments in Gusev Crater, Mars

NASA Astrophysics Data System (ADS)

Des Marais, D. J.; Athena Science Team

2007-12-01

In order to be habitable for microbial life as we know it, an environment must provide nutrient elements, energy and liquid water. We assess the potential for habitable environments in the areas explored by the MER rover Spirit. These areas include the basaltic plains near Columbia Memorial Station, West Spur, Husband Hill, and the inner basin south of Husband Hill. Little aqueous activity apparently occurred in Gusev crater since the basaltic plains were emplaced in Hesperian times, therefore the basaltic plains were highly unlikely to have sustained habitable environments. The Columbia Hills, located ~3 km southeast of the landing site, are older than the surrounding basaltic plains. Aqueous processes have extensively altered bedrock in the Columbia Hills. Ferrous iron in the original, unaltered parent rock of hills materials has typically been oxidized extensively to form ferric oxides, hydroxides, and other ferric minerals. Migrating fluids have removed Ca and other cations, allowing residual Al to become relatively more abundant, and fluids added sulfates and chlorides. In subsurface environments on Earth, microorganisms can obtain key nutrients from the weathering of basalts. Materials examined in the Columbia Hills have comparable or greater abundances of these elements than do MORB. Wishstone rock and Watchtower outcrop have very high contents of phosphorous. Chemoautotrophs ("chemical- feeders" that obtain energy from inorganic chemicals) can thrive in subsurface environments. Mixing oxidized constituents from surface environments with generally more reduced constituents from subsurface rocks and thermal emanations provides energy to sustain microorganisms. Ferrous iron in parent materials in the Columbia Hills has been oxidized to form a variety of ferric minerals. On Earth, microbial processes have been documented to contribute to the production of goethite, hematite and other iron oxides. Observations by Spirit are consistent with the possibility that liquid water, nutrients and sources of chemical energy were simultaneously available to sustain habitable conditions in subsurface Columbia Hills materials at least some time in the distant (Noachian?) past. There is as yet no evidence that these conditions ever existed at the surface. Future research must seek to determine whether ancient migrating fluids in Gusev ever achieved the water activity necessary to sustain life.

Biologically-initiated rock crust on sandstone: Mechanical and hydraulic properties and resistance to erosion

NASA Astrophysics Data System (ADS)

Slavík, Martin; Bruthans, Jiří; Filippi, Michal; Schweigstillová, Jana; Falteisek, Lukáš; Řihošek, Jaroslav

2017-02-01

Biocolonization on sandstone surfaces is known to play an important role in rock disintegration, yet it sometimes also aids in the protection of the underlying materials from rapid erosion. There have been few studies comparing the mechanical and/or hydraulic properties of the BIRC (Biologically-Initiated Rock Crust) with its subsurface. As a result, the overall effects of the BIRC are not yet well understood. The objective of the present study was to briefly characterize the BIRC from both the mineralogical and biological points of view, and especially to quantify the effect of the BIRC upon the mechanical and hydraulic properties of friable sandstone. The mineralogical investigation of a well-developed BIRC showed that its surface is enriched in kaolinite and clay- to silt-sized quartz particles. Total organic carbon increases with the age of the BIRC. Based on DNA sequencing and microscopy, the BIRC is formed by various fungi, including components of lichens and green algae. Using the method of drilling resistance, by measuring tensile strength, and based on water jet testing, it was determined that a BIRC is up to 12 times less erodible and has 3-35 times higher tensile strength than the subsurface friable sandstone. Saturated hydraulic conductivity of the studied BIRC is 15-300 times lower than the subsurface, and was measured to also decrease in capillary water absorption (2-33 times). Water-vapor diffusion is not significantly influenced by the presence of the BIRC. The BIRC thus forms a hardened surface which protects the underlying material from rain and flowing water erosion, and considerably modifies the sandstone's hydraulic properties. Exposing the material to calcination (550 °C), and experiments with the enzyme zymolyase indicated that a major contribution to the surface hardening is provided by organic matter. In firmer sandstones, the BIRC may still considerably decrease the rate of weathering, as it is capable of providing cohesion to strongly weathered (and disintegrated) sandstone surfaces. However, only a near-surface zone of the sandstone is stabilized by the BIRC, and additional sources of stabilization (gravity-induced stress, inorganic cement, etc.) contribute to the resistance of the subsurface zone of sandstone exposures.

GIS based 3D visualization of subsurface and surface lineaments / faults and their geological significance, northern tamil nadu, India

NASA Astrophysics Data System (ADS)

Saravanavel, J.; Ramasamy, S. M.

2014-11-01

The study area falls in the southern part of the Indian Peninsular comprising hard crystalline rocks of Archaeozoic and Proterozoic Era. In the present study, the GIS based 3D visualizations of gravity, magnetic, resistivity and topographic datasets were made and therefrom the basement lineaments, shallow subsurface lineaments and surface lineaments/faults were interpreted. These lineaments were classified as category-1 i.e. exclusively surface lineaments, category-2 i.e. surface lineaments having connectivity with shallow subsurface lineaments and category-3 i.e. surface lineaments having connectivity with shallow subsurface lineaments and basement lineaments. These three classified lineaments were analyzed in conjunction with known mineral occurrences and historical seismicity of the study area in GIS environment. The study revealed that the category-3 NNE-SSW to NE-SW lineaments have greater control over the mineral occurrences and the N-S, NNE-SSW and NE-SW, faults/lineaments control the seismicities in the study area.

Enigmatic organosiliceous rocks in the 2000 Ma petrified oil field in Russian Fennoscandia

NASA Astrophysics Data System (ADS)

Deines, Yu.; Melezhik, V.; Lepland, A.; Filippov, M.; Romashkin, A.; Rychanchik, D.

2009-04-01

The c. 2000 Ma, 900 m-thick, Zaonezhskaja Formation in the Onega basin, Russian Fennoscandia, contains one of the greatest accumulations of organic matter (OM) in the Early Precambrian. It also represents a unique preservation of a supergiant petrified oil field. Zaonezhskaja Formation rocks are greenschist-facies volcaniclastic greywackes (distal turbidites), dolostone and limestones, mafic tuffs and lavas intruded by numerous mafic sills. Several sedimentary beds are enriched in OM with the overall content of total organic carbon (TOC) ranging from 0.1 to 16 wt.% whereas d13C varies between -44 and -17 per mil(V-PDB). The formation contains plentiful evidence of generation and migration of oil (now petrified) as well as oil traps. Results of geophysical surveys combined with drillcore data, including results recently obtained within the framework of the Fennoscandian Arctic Russia - Drilling Early Earth Project (FAR-DEEP), revealed numerous bodies of organosiliceous rocks (OSR) containing mainly silica (c. 57 wt.% SiO2), organic carbon (up to 40 wt.%), Al2O3 (c. 5 wt.%), S (c. 2 wt.%), and minor K, Mg, Fe, Ca and Ti. d13C of the OSR ranges between -40 and -20 per mil. The OSR form crudely stratified beds, cupola-like bodies or veins. The cupola-like bodies show cross-cutting (intrusive) contacts with the host turbiditic greywackes, reach thicknesses of 120 m with a lateral extent of several hundreds of metres. Veins are a few tens of centimetres thick. The OSR show close spatial association with gabbro sills. Although different fabrics have been recognised in the OSR, syngenetic macro- and microbreccias per se are the most common rock types. Fragments of different sedimentary rocks, as well as those with alternating C-rich and C-poor concentric lamina are present. The latter suggests precipitation from hydrothermal fluids. The nature of the OSR remains enigmatic. Several models have been advanced for explanation of origin of the OSR. However, neither of them could explain the source, and joint transport of two major components, namely silica and OM. We propose a model involving a hydrothermal system initiated by heat produced during the emplacement of numerous mafic intrusive bodies. Such heat may have created the necessary temperature gradient for earlier oil generation, thermal oil to gas cracking, and initiation of shallow-seated, sub-surface, hydrothermal circulation. The proposed result would have been the mingling of silica leached from mafic rocks with hydrocarbon, and gas (primarily CO2, CH4) extracted from the host sedimentary rocks. Such a gas-rich C-Si-H2O substance would have migrated into permeable beds. A high sedimentation rate, as expected in many turbiditic depositional environments, would have produced a high lithostatic pressure on to unlithified beds during the course of the basin subsidence. This would have forced gas-rich C-Si-H2O fluids that moved either laterally along permeable beds or vertically along zones of weakness. In the first case, sediments 'impregnated' with gas-rich C-Si-H2O fluids would have formed stratigraphic beds of OSR, whereas in the second case the result would been crosscutting veins. Beds may retain some primary layering, whereas veins do not. If veins reached the seafloor, the sediment - C-Si-H2O mush would have extruded in the form of a mud volcano / hydrothermal mound, and thus formed a cupola-like morphology. During the course of compression, the sediment - C-Si-H2O mush might have experienced several stages of partial lithification, as well as fluidisation processes leading to the formation of several generations of micro- and macro-brecciated rocks. The large d13C range of reduced carbon in the OSR suggests a complex maturation process of the biogenic OM. Further detailed microstructural, geochemical, isotopic and biomarker studies are planned for distinguishing between biological and abiological processes involved in the formation of the enigmatic OSR.

Obtaining higher-accuracy estimates of water-rich rocks and water-poor sand dunes on Mars in active neutron experiments

NASA Astrophysics Data System (ADS)

Gabriel, T. S. J.; Hardgrove, C.; Litvak, M. L.; Nowicki, S.; Mitrofanov, I. G.; Boynton, W. V.; Fedosov, F.; Golovin, D.; Jun, I.; Mischna, M.; Tate, C. G.; Moersch, J.; Harshman, K.; Kozyrev, A.; Malakhov, A. V.; Mokrousov, M.; Nikiforov, S.; Sanin, A. B.; Vostrukhin, A.; Thompson, L. M.

2017-12-01

The Dynamic Albedo of Neutrons (DAN) experiment on the Mars Science Laboratory Curiosity Rover delivers high-energy (14.1 MeV) pulses of neutrons into the surface when operating in "active" mode. Neutrons are moderated in the subsurface and return to two detectors to provide a time-of-flight profile in 64 time-bins in epithermal and thermal energy ranges. Results are compared to simulations of the experiment in the Monte Carlo N-Particle Transport Code where several aspects are modeled including the DAN detectors, neutron source, rover components, and underlying rock. Models can be improved by increasing the fidelity of the rock geochemistry as informed by instruments including the Alpha Particle X-Ray Spectrometer (APXS). Furthermore, increasing the fidelity of the rock morphology in models is enabled by the suite of imaging instruments on the rover.To rapidly interpret DAN data a set of pre-simulated generic rock density and bulk geochemistry models are compared to several DAN active observations. While, to first order, this methodology provides an indication of significant geochemical changes in the subsurface, higher-fidelity models should be used to provide accurate constraints on water content, depth of geologic layers, or abundance of neutron absorbers. For example, in high-silicon, low-iron rocks observed along the rover's traverse, generic models can differ by several wt%H2O from models that use APXS measurements of nearby drill samples. Accurate measurements of high-silicon targets are necessary in outlining the extent of aqueous alteration and hydrothermal activity in Gale Crater. Additionally, we find that for DAN active experiments over sand dunes best-fit models can differ by greater than 0.5 wt%HO when the upper layer density is reduced by 0.6 g/cm3 to account for the low-bulk density of sand. In areas where the rock geochemistry differs little from generic models the difference in results is expectedly less disparate. We report refined wt%HO values for high-silicon, aqueously-altered rock and comparatively dry sand dunes along the rover traverse. We also outline the methodology for providing accurate geochemical and morphological constraints using DAN active measurements.

A numerical study of EGS heat extraction process based on a thermal non-equilibrium model for heat transfer in subsurface porous heat reservoir

NASA Astrophysics Data System (ADS)

Chen, Jiliang; Jiang, Fangming

2016-02-01

With a previously developed numerical model, we perform a detailed study of the heat extraction process in enhanced or engineered geothermal system (EGS). This model takes the EGS subsurface heat reservoir as an equivalent porous medium while it considers local thermal non-equilibrium between the rock matrix and the fluid flowing in the fractured rock mass. The application of local thermal non-equilibrium model highlights the temperature-difference heat exchange process occurring in EGS reservoirs, enabling a better understanding of the involved heat extraction process. The simulation results unravel the mechanism of preferential flow or short-circuit flow forming in homogeneously fractured reservoirs of different permeability values. EGS performance, e.g. production temperature and lifetime, is found to be tightly related to the flow pattern in the reservoir. Thermal compensation from rocks surrounding the reservoir contributes little heat to the heat transmission fluid if the operation time of an EGS is shorter than 15 years. We find as well the local thermal equilibrium model generally overestimates EGS performance and for an EGS with better heat exchange conditions in the heat reservoir, the heat extraction process acts more like the local thermal equilibrium process.

Enhanced Structural Interpretation Using Multitrace Seismic Attribute For Oligo-Miocene Target at Madura Strait Offshore

NASA Astrophysics Data System (ADS)

Pratama Wahyu Hidayat, Putra; Hary Murti, Antonius; Sudarmaji; Shirly, Agung; Tiofan, Bani; Damayanti, Shinta

2018-03-01

Geometry is an important parameter for the field of hydrocarbon exploration and exploitation, it has significant effect to the amount of resources or reserves, rock spreading, and risk analysis. The existence of geological structure or fault becomes one factor affecting geometry. This study is conducted as an effort to enhance seismic image quality in faults dominated area namely offshore Madura Strait. For the past 10 years, Oligo-Miocene carbonate rock has been slightly explored on Madura Strait area, the main reason because migration and trap geometry still became risks to be concern. This study tries to determine the boundary of each fault zone as subsurface image generated by converting seismic data into variance attribute. Variance attribute is a multitrace seismic attribute as the derivative result from amplitude seismic data. The result of this study shows variance section of Madura Strait area having zero (0) value for seismic continuity and one (1) value for discontinuity of seismic data. Variance section shows the boundary of RMKS fault zone with Kendeng zone distinctly. Geological structure and subsurface geometry for Oligo-Miocene carbonate rock could be identified perfectly using this method. Generally structure interpretation to identify the boundary of fault zones could be good determined by variance attribute.

The distribution of particulate material on Mars

NASA Technical Reports Server (NTRS)

Christensen, Philip R.

1991-01-01

The surface materials on Mars were extensively studied using a variety of spacecraft and Earth-based remote sensing observations. These measurements include: (1) diurnal thermal measurements, used to determine average particle size, rock abundance, and the presence of crusts; (2) radar observations, used to estimate the surface slope distributions, wavelength scale roughness, and density; (3) radio emission observations, used to estimate subsurface density; (4) broadband albedo measurements, used to study the time variation of surface brightness and dust deposition and removal; and (5) color observations, used to infer composition, mixing, and the presence of crusts. Remote sensing observations generally require some degree of modeling to interpret, making them more difficult to interpret than direct observations from the surface. They do, however, provide a means for examining the surface properties over the entire planet and a means of sampling varying depths within the regolith. Albedo and color observations only indicate the properties of the upper-most few microns, but are very sensitive to thin, sometimes emphemeral dust coatings. Thermal observations sample the upper skin depth, generally 2 to 10 cm. Rock abundance measurements give an indirect indication of surface mantling, where the absence of rocks suggests mantles of several meters. Finally, radar and radio emission data can penetrate several meters into the surface, providing an estimate of subsurface density and roughness.

Petrophysical laboratory invertigations of carbon dioxide storage in a subsurface saline aquifer in Ketzin/Germany within the scope of CO2SINK

NASA Astrophysics Data System (ADS)

Zemke, K.; Kummmerow, J.; Wandrey, M.; Co2SINK Group

2009-04-01

Since June of 2008 carbon dioxide has been injected into a saline aquifer at the Ketzin test site [Würdemann et al., this volume]. The food grade CO2 is injected into a sandstone zone of the Stuttgart formation at ca. 650 m depth at 35°C reservoir temperature and 62 bar reservoir pressure. With the injection of CO2 into the geological formation, chemical and physical reservoir characteristics are changed depending on pressure, temperature, fluid chemistry and rock composition. Fluid-rock interaction could comprise dissolution of non-resistant minerals in CO2-bearing pore fluids, cementing of the pore space by precipitating substances from the pore fluid, drying and disintegration of clay minerals and thus influence of the composition and activities of the deep biosphere. To testing the injection behaviour of CO2 in water saturated rock and to evaluate the geophysical signature depending on the thermodynamic conditions, flow experiments with water and CO2 have been performed on cores of the Stuttgart formation from different locations including new wells of ketzin test site. The studied core material is an unconsolidated fine-grained sandstone with porosity values from 15 to 32 %. Permeability, electrical resistivity, and sonic wave velocities and their changes with pressure, saturation and time have been studied under simulated in situ conditions. The flow experiments conducted over several weeks with brine and CO2 showed no significant changes of resistivity and velocity and a slightly decreasing permeability. Pore fluid analysis showed mobilization of clay and some other components. A main objective of the CO2Sink laboratory program is the assessment of the effect of long-term CO2 exposure on reservoir rocks to predict the long-term behaviour of geological CO2 storage. For this CO2 exposure experiments reservoir rock samples were exposed to CO2 saturated reservoir fluid in corrosion-resistant high pressure vessels under in situ temperature and pressure conditions over a period of several months. Before and after the CO2 exposure experiment cyclic measurements of physical properties were carried out on these cores in a mechanical testing system. After experimental runs of up to 3 months no significant changes in flow and petrophysical data were observed. [For the microbilogical studies see Wandrey et al., this volume.] To study the impact of fluid-rock interactions on petrophysical parameters, porosity and pore radii distribution have been investigated before and after the experiment by NMR relaxation and mercury-injection. NMR measurements on rock core plugs saturated with brine may return valuable information on the porous structure of the rock core. The distribution of NMR-T2 values (CPMG) reflects the pore sizes within the rock core. NMR pore size is a derivative of the ratio pore surface/volume. The mercury injection pore size is an area-equivalent diameter of the throats connecting the pore system. Most of the tested samples show in the NMR measurements a slightly increasing porosity and a higher part of large pores. The mercury measurements and thin- section for microstructural characterisation after the CO2 exposure will be done at a later date.

Parallel heater system for subsurface formations

DOEpatents

Harris, Christopher Kelvin [Houston, TX; Karanikas, John Michael [Houston, TX; Nguyen, Scott Vinh [Houston, TX

2011-10-25

A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

Prediction of future subsurface temperatures in Korea

NASA Astrophysics Data System (ADS)

Lee, Y.; Kim, S. K.; Jeong, J.; SHIN, E.

2017-12-01

The importance of climate change has been increasingly recognized because it has had the huge amount of impact on social, economic, and environmental aspect. For the reason, paleoclimate change has been studied intensively using different geological tools including borehole temperatures and future surface air temperatures (SATs) have been predicted for the local areas and the globe. Future subsurface temperatures can have also enormous impact on various areas and be predicted by an analytical method or a numerical simulation using measured and predicted SATs, and thermal diffusivity data of rocks. SATs have been measured at 73 meteorological observatories since 1907 in Korea and predicted at same locations up to the year of 2100. Measured SATs at the Seoul meteorological observatory increased by about 3.0 K from the year of 1907 to the present. Predicted SATs have 4 different scenarios depending on mainly CO2 concentration and national action plan on climate change in the future. The hottest scenario shows that SATs in Korea will increase by about 5.0 K from the present to the year of 2100. In addition, thermal diffusivity values have been measured on 2,903 rock samples collected from entire Korea. Data pretreatment based on autocorrelation analysis was conducted to control high frequency noise in thermal diffusivity data. Finally, future subsurface temperatures in Korea were predicted up to the year of 2100 by a FEM simulation code (COMSOL Multiphysics) using measured and predicted SATs, and thermal diffusivity data in Korea. At Seoul, the results of predictions show that subsurface temperatures will increase by about 5.4 K, 3.0 K, 1.5 K, and 0.2 K from the present to 2050 and then by about 7.9 K, 4.8 K, 2.5 K, and 0.5 K to 2100 at the depths of 10 m, 50 m, 100 m, and 200 m, respectively. We are now proceeding numerical simulations for subsurface temperature predictions for 73 locations in Korea.

Geologic and hydrologic controls on the economic potential of hydrothermal systems associated with upper crustal plutons

NASA Astrophysics Data System (ADS)

Weis, Philipp; Driesner, Thomas; Scott, Samuel; Lecumberri-Sanchez, Pilar

2016-04-01

Heat and mass transport in hydrothermal systems associated with upper crustal magmatic intrusions can result in resources with large economic potential (Kesler, 1994). Active hydrothermal systems can form high-enthalpy geothermal reservoirs with the possibility for renewable energy production. Fossil continental or submarine hydrothermal systems may have formed ore deposits at variable crustal depths, which can be mined near today's surface with an economic profit. In both cases, only the right combination of first-order geologic and hydrologic controls may lead to the formation of a significant resource. To foster exploration for these hydrothermal georesources, we need to improve our understanding of subsurface fluxes of mass and energy by combining numerical process modelling, observations at both active and fossil systems, as well as knowledge of fluid and rock properties and their interactions in natural systems. The presentation will highlight the role of non-linear fluid properties, phase separation, salt precipitation, fluid mixing, permeability structure, hydraulic fracturing and the transition from brittle to ductile rock behavior as major geologic and hydrologic controls on the formation of high-enthalpy and supercritical geothermal resources (Scott et al., 2015), and magmatic-hydrothermal mineral resources, such as porphyry copper, massive sulfide and epithermal gold deposits (Lecumberri-Sanchez et al., 2015; Weis, 2015). References: Kesler, S. E., 1994: Mineral Resources, economics and the environment, New York, McMillan, 391. Lecumberri-Sanchez, P., Steele-MacInnis, M., Weis, P., Driesner, T., Bodnar, R.J. (2015): Salt precipitation in magmatic-hydrothermal systems associated with upper crustal plutons. Geology, v. 43, p. 1063-1066, doi:10.1130/G37163.1 Scott, S., Driesner, T., Weis, P. (2015): Geologic controls on supercritical geothermal resources above magmatic intrusions. Nature Communications, 6:7837 doi: 10.1038/ncomms8837 Weis, P. (2015): The dynamic interplay between saline fluid flow and rock permeability in magmatic-hydrothermal systems. Geofluids, 15, 350-371.

Micro-scale displacement of NAPL by surfactant and microemulsion in heterogeneous porous media

NASA Astrophysics Data System (ADS)

Javanbakht, Gina; Arshadi, Maziar; Qin, Tianzhu; Goual, Lamia

2017-07-01

Industrial processes such as remediation of oil-contaminated aquifers and enhanced oil recovery (EOR) often utilize chemical additives to increase the removal of non-aqueous phase liquids (NAPLs) from subsurface formations. Although the majority of crude oils are classified as LNAPLs, they often contain heavy molecules (DNAPLs) such as asphaltenes that tend to adsorb on minerals and alter their wettability. Effective additives are therefore those that can reduce the threshold capillary pressure, thus mobilizing LNAPL inside pore spaces and solubilizing DNAPL from rock surfaces. Nonionic surfactants in brine have often been injected to oil or contaminated aquifer formations in order to enhance NAPL displacement through IFT reduction. Recent studies revealed that surfactant-based microemulsions have a higher tendency to alter the wettability of surfaces, compared to surfactants alone, leading to more effective NAPL removal. However, the impact of these additives on pore-scale displacement mechanisms and multi-phase fluid occupancy in porous media is, to date, still unclear. In this study, x-ray microtomography experiments were performed to investigate the impact of surfactants and microemulsions on the mobilization and solubilization of NAPL in heterogeneous rocks. Saturation profiles indicated that an incremental NAPL removal was attained by addition of microemulsion to brine, compared with surfactant. Residual cluster size distributions revealed that microemulsions could break up large clusters into smaller disconnected ones, improving their mobilization in the rock. In-situ contact angle measurements showed that microemulsions could reverse the wettability of rough contaminated surfaces to a higher extent than surfactants. Unlike surfactant alone, the surfactant-solvent blend in the carrier fluid of microemulsions was able to penetrate rough grain surfaces, particularly those of dolomite cement, and desorb asphaltenes in the form of small-emulsified NAPL droplets, which were eventually washed away by the continuous flow process. The greater wettability alteration caused by microemulsions resulted in a lower threshold capillary pressure, which in turn promoted the mobilization of NAPL ganglia more than surfactant alone.

Microscale mapping of alteration conditions and potential biosignatures in basaltic-ultramafic rocks on early Earth and beyond.

PubMed

Grosch, Eugene G; McLoughlin, Nicola; Lanari, Pierre; Erambert, Muriel; Vidal, Olivier

2014-03-01

Subseafloor environments preserved in Archean greenstone belts provide an analogue for investigating potential subsurface habitats on Mars. The c. 3.5-3.4 Ga pillow lava metabasalts of the mid-Archean Barberton greenstone belt, South Africa, have been argued to contain the earliest evidence for microbial subseafloor life. This includes candidate trace fossils in the form of titanite microtextures, and sulfur isotopic signatures of pyrite preserved in metabasaltic glass of the c. 3.472 Ga Hooggenoeg Formation. It has been contended that similar microtextures in altered martian basalts may represent potential extraterrestrial biosignatures of microbe-fluid-rock interaction. But despite numerous studies describing these putative early traces of life, a detailed metamorphic characterization of the microtextures and their host alteration conditions in the ancient pillow lava metabasites is lacking. Here, we present a new nondestructive technique with which to study the in situ metamorphic alteration conditions associated with potential biosignatures in mafic-ultramafic rocks of the Hooggenoeg Formation. Our approach combines quantitative microscale compositional mapping by electron microprobe with inverse thermodynamic modeling to derive low-temperature chlorite crystallization conditions. We found that the titanite microtextures formed under subgreenschist to greenschist facies conditions. Two chlorite temperature groups were identified in the maps surrounding the titanite microtextures and record peak metamorphic conditions at 315 ± 40°C (XFe3+(chlorite) = 25-34%) and lower-temperature chlorite veins/microdomains at T = 210 ± 40°C (lower XFe3+(chlorite) = 40-45%). These results provide the first metamorphic constraints in textural context on the Barberton titanite microtextures and thereby improve our understanding of the local preservation conditions of these potential biosignatures. We suggest that this approach may prove to be an important tool in future studies to assess the biogenicity of these earliest candidate traces of life on Earth. Furthermore, we propose that this mapping approach could also be used to investigate altered mafic-ultramafic extraterrestrial samples containing candidate biosignatures.

Discrete fracture modeling of multiphase flow and hydrocarbon production in fractured shale or low permeability reservoirs

NASA Astrophysics Data System (ADS)

Hao, Y.; Settgast, R. R.; Fu, P.; Tompson, A. F. B.; Morris, J.; Ryerson, F. J.

2016-12-01

It has long been recognized that multiphase flow and transport in fractured porous media is very important for various subsurface applications. Hydrocarbon fluid flow and production from hydraulically fractured shale reservoirs is an important and complicated example of multiphase flow in fractured formations. The combination of horizontal drilling and hydraulic fracturing is able to create extensive fracture networks in low permeability shale rocks, leading to increased formation permeability and enhanced hydrocarbon production. However, unconventional wells experience a much faster production decline than conventional hydrocarbon recovery. Maintaining sustainable and economically viable shale gas/oil production requires additional wells and re-fracturing. Excessive fracturing fluid loss during hydraulic fracturing operations may also drive up operation costs and raise potential environmental concerns. Understanding and modeling processes that contribute to decreasing productivity and fracturing fluid loss represent a critical component for unconventional hydrocarbon recovery analysis. Towards this effort we develop a discrete fracture model (DFM) in GEOS (LLNL multi-physics computational code) to simulate multiphase flow and transfer in hydraulically fractured reservoirs. The DFM model is able to explicitly account for both individual fractures and their surrounding rocks, therefore allowing for an accurate prediction of impacts of fracture-matrix interactions on hydrocarbon production. We apply the DFM model to simulate three-phase (water, oil, and gas) flow behaviors in fractured shale rocks as a result of different hydraulic stimulation scenarios. Numerical results show that multiphase flow behaviors at the fracture-matrix interface play a major role in controlling both hydrocarbon production and fracturing fluid recovery rates. The DFM model developed in this study will be coupled with the existing hydro-fracture model to provide a fully integrated geomechanical and reservoir simulation capability for an accurate prediction and assessment of hydrocarbon production and hydraulic fracturing performance. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Design of Fit-for-Purpose Cement to Restore Cement-Caprock Seal Integrity

NASA Astrophysics Data System (ADS)

Provost, R.

2015-12-01

This project aims to study critical research needs in the area of rock-cement interfaces, with a special focus on crosscutting applications in the Wellbore Integrity Pillar of the SubTER initiative. This study will focus on design and test fit-for-purpose cement formulations. The goals of this project are as follows: 1) perform preliminary study of dispersing nanomaterial admixtures in Ordinary Portland Cement (OPC) mixes, 2) characterize the cement-rock interface, and 3) identify potential high-performance cement additives that can improve sorption behavior, chemical durability, bond strength, and interfacial fracture toughness, as appropriate to specific subsurface operational needs. The work presented here focuses on a study of cement-shale interfaces to better understand failure mechanisms, with particular attention to measuring bond strength at the cement-shale interface. Both experimental testing and computational modeling were conducted to determine the mechanical behavior at the interface representing the interaction of cement and shale of a typical wellbore environment. Cohesive zone elements are used in the finite element method to computationally simulate the interface of the cement and rock materials with varying properties. Understanding the bond strength and mechanical performance of the cement-formation interface is critical to wellbore applications such as sequestration, oil and gas production and exploration and nuclear waste disposal. Improved shear bond strength is an indication of the capability of the interface to ensure zonal isolation and prevent zonal communication, two crucial goals in preserving wellbore integrity. Understanding shear bond strength development and interface mechanics will provide an idea as to how the cement-formation interface can be altered under environmental changes (temperature, pressure, chemical degradation, etc.) so that the previously described objectives can be achieved. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND #: SAND2015-6523 A

Geochemical mass-balance to study the relative weathering rates of various formations in a complex watershed of lower Himalayas

NASA Astrophysics Data System (ADS)

Chattopadhyay, Pallavi; Kar, Swagat; Chouhan, Ramesh

2017-04-01

Weathering of rocks is a major process and believed to have the potential to alter Earth's surface. Aglar, a watershed in Garhwal Lesser Himalayas is identified and various formations of this complex geology are studied to understand the weathering process. A stream passes through the fault that divides the watershed into two slopes which have different lithotectonic units. Paligar and Belgar are the two main tributaries of Aglar stream flowing along the slopes respectively and joining at the valley near Thatyur village, India. Rocks like quartzite and limestone are generally hard, massive and resistant to weathering. However, sedimentary rocks are vulnerable to weathering and erosion. On the other hand, phyllites and schists are characterized by flaky minerals which weather quickly and promote instability . Aglar has all of them. The weathering processes are studied first using the hydrochemistry of Aglar river through major cations (Ca2+, Mg2+, Na+, K+) and major anions (SO42-, HCO-3, Cl-, NO3-). The discharges at various sampling points are calculated using area - velocity method. The basic idea in describing the discharge of material in a river is to estimate the mass of the substances transported through a cross section of the river per second. Dominance of Ca2+, Mg2+ and HCO-3 indicates that carbonate weathering is the major chemical weathering process near Belgar river. Paligar river has lower conductivity values compared to Belgar river which illustrates lower ionic concentrations. Mass-balance calculations are found often skewed and suggest the role of subsurface groundwater flow to explain the uncharacterized load. Southern side of the watershed with higher percentage of forest cover is found to have higher chemical weathering rates compared to the other slope having relatively lesser vegetation. These higher rates demonstrate the higher stream discharge load in that slope.

Executive Summary Report - FY80 Geotechnical Siting Investigations.

DTIC Science & Technology

1980-11-30

MX siting investigation, geotech- nical summary, prime characterization sites, Rio Grande /Highlands Candidate Siting Province report. TR-26d , 19781...s * Subsurface projectlro of to sul rock limits ab ser i Oelneation of ro-k f o- Geologic high (-7000 !ps -) w- we velocities -Obta r Borings

Stochastic Seismic Inversion and Migration for Offshore Site Investigation in the Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Son, J.; Medina-Cetina, Z.

2017-12-01

We discuss the comparison between deterministic and stochastic optimization approaches to the nonlinear geophysical full-waveform inverse problem, based on the seismic survey data from Mississippi Canyon in the Northern Gulf of Mexico. Since the subsea engineering and offshore construction projects actively require reliable ground models from various site investigations, the primary goal of this study is to reconstruct the accurate subsurface information of the soil and rock material profiles under the seafloor. The shallow sediment layers have naturally formed heterogeneous formations which may cause unwanted marine landslides or foundation failures of underwater infrastructure. We chose the quasi-Newton and simulated annealing as deterministic and stochastic optimization algorithms respectively. Seismic forward modeling based on finite difference method with absorbing boundary condition implements the iterative simulations in the inverse modeling. We briefly report on numerical experiments using a synthetic data as an offshore ground model which contains shallow artificial target profiles of geomaterials under the seafloor. We apply the seismic migration processing and generate Voronoi tessellation on two-dimensional space-domain to improve the computational efficiency of the imaging stratigraphical velocity model reconstruction. We then report on the detail of a field data implementation, which shows the complex geologic structures in the Northern Gulf of Mexico. Lastly, we compare the new inverted image of subsurface site profiles in the space-domain with the previously processed seismic image in the time-domain at the same location. Overall, stochastic optimization for seismic inversion with migration and Voronoi tessellation show significant promise to improve the subsurface imaging of ground models and improve the computational efficiency required for the full waveform inversion. We anticipate that by improving the inversion process of shallow layers from geophysical data will better support the offshore site investigation.

Integration of P- and SH-wave high-resolution seismic reflection and micro-gravity techniques to improve interpretation of shallow subsurface structure: New Madrid seismic zone

USGS Publications Warehouse

Bexfield, C.E.; McBride, J.H.; Pugin, Andre J.M.; Ravat, D.; Biswas, S.; Nelson, W.J.; Larson, T.H.; Sargent, S.L.; Fillerup, M.A.; Tingey, B.E.; Wald, L.; Northcott, M.L.; South, J.V.; Okure, M.S.; Chandler, M.R.

2006-01-01

Shallow high-resolution seismic reflection surveys have traditionally been restricted to either compressional (P) or horizontally polarized shear (SH) waves in order to produce 2-D images of subsurface structure. The northernmost Mississippi embayment and coincident New Madrid seismic zone (NMSZ) provide an ideal laboratory to study the experimental use of integrating P- and SH-wave seismic profiles, integrated, where practicable, with micro-gravity data. In this area, the relation between "deeper" deformation of Paleozoic bedrock associated with the formation of the Reelfoot rift and NMSZ seismicity and "shallower" deformation of overlying sediments has remained elusive, but could be revealed using integrated P- and SH-wave reflection. Surface expressions of deformation are almost non-existent in this region, which makes seismic reflection surveying the only means of detecting structures that are possibly pertinent to seismic hazard assessment. Since P- and SH-waves respond differently to the rock and fluid properties and travel at dissimilar speeds, the resulting seismic profiles provide complementary views of the subsurface based on different levels of resolution and imaging capability. P-wave profiles acquired in southwestern Illinois and western Kentucky (USA) detect faulting of deep, Paleozoic bedrock and Cretaceous reflectors while coincident SH-wave surveys show that this deformation propagates higher into overlying Tertiary and Quaternary strata. Forward modeling of micro-gravity data acquired along one of the seismic profiles further supports an interpretation of faulting of bedrock and Cretaceous strata. The integration of the two seismic and the micro-gravity methods therefore increases the scope for investigating the relation between the older and younger deformation in an area of critical seismic hazard. ?? 2006 Elsevier B.V. All rights reserved.

Hydraulic properties of siliciclastic geothermal reservoir rocks under triaxial stress conditions, a multidisciplinary approach.

NASA Astrophysics Data System (ADS)

Bakker, Richard; Gholizadeh Doonechaly, Nima; Bruhn, David

2017-04-01

Cretaceous Sandstone bodies in the subsurface of western Netherlands are already used for heating some of the greenhouses in that area. The reservoirs used are typically at depths between 1500 and 3000m, with temperatures generally <100 ˚C. For higher temperature applications deeper reservoirs are required. However, deeper reservoirs are subjected to higher effective pressures due to more overburden, which can lead to more compacted rocks, and thereby reduced permeability. We assess the effects of effective pressure on Triassic Buntsandstein, a formation targeted to act as a deep geothermal reservoir in the western Netherlands. Rock samples are acquired from laterally equivalent quarries and prepared for permeability measurements within a tri-axial apparatus. To determine anisotropy, cores are drilled both perpendicular and parallel to bedding. Experiments are conducted by maintaining hydrostatic confining pressure, stepwise increasing up to 700 bar (if still permeable enough for accurate measurements) and a pore pressure of 25 bar. At each step the permeability is assessed by imposing a number of constant flow rates and continuous measurement of the pore pressure difference between up and downstream reservoirs. Throughout the experiment the sample strain is measured in radial and axial directions, such that elastic constants can be determined and micromechanical mechanisms may be observed. In addition to measurements on in-tact rock samples, we also assess the effect of induced fracturing on permeability by similar measurements. First, rock samples are fractured within the tri-axial cell with normal jacketing to evaluate the stress conditions of failure. Secondly, the experiment is repeated using relatively strong jackets which remain sealing after sample failure, allowing for permeability measurements. Preliminary results show that an increase of confining pressure leads to a decrease of permeability by three orders of magnitude, from 1e-13 to 1e-16 m2. Anisotropy results in permeability parallel to bedding to be roughly one order of magnitude higher than perpendicular to it. Based on the collected data, the validity of the available exponential permeability-porosity-stress relationship is assessed and the model parameters with the best fitting characteristic is chosen for the selected formation. The established relationship is then used as an input for field scale numerical simulation of cold fluid circulation in Buntsandstein formation to predict the reservoir behavior over longer term of fluid circulation. The Finite Element Method is used to evaluate the reservoir behaviour during injection/production of the cold/hot fluid in a fully coupled poro-thermo-elastic environment. Weighted residual method is used for deriving the weak formulation of the mass-, momentum- and energy balance equations. Consequently the standard Galerkin approach is used for spatial discretization of the weak formulas. Temporal discretization is also carried out in a fully implicit manner to avoid the time-stepping limitation. The preliminary results of this study show a promising capacity of heat extraction from the Buntsandstein formation as a geothermal reservoir within western Netherlands.

Distribution of surface deposits in the Gijón urban subsurface (NW Spain)

NASA Astrophysics Data System (ADS)

López-Fernández, Carlos; Pando, Luis; María Díaz-Díaz, Luis; Arias, Daniel; Flor-Blanco, Germán

2016-04-01

Gijón is the second most populous city (278.285 inhabitants in 2015) of the Spanish north coast. The urban subsurface is mostly formed (≈80%) by Quaternary sediments which exceeds 20 meters of thickness when cover the Jurassic carbonate basement (Gijón Formation). This work has allowed to know the spatial distribution of the different types of sediments in urban area. To do this, a GIS database was developed that contains data from more than 450 geotechnical reports. Information provided by fieldwork and the exploration of excavation works in progress throughout the city was also incorporated. Currently, the geodatabase developed comprises more than 1,400 site investigation points: boreholes, dynamic probing and trial pits. This has been supplemented with hundreds on-site and laboratory tests carried out on core samples of soils and rocks, performed following renowned testing standards. Quaternary formations, largely concealed below man-made fills, set up two main areas composed by granular and cohesive soils: the littoral zone at the northern urban perimeter and the continental zone at the southern sector. The first one, fluvial-marine deposits, consist of sandy sediments related to beach/dune systems and marsh deposits, with gravels, organogenic mud and layers of Holocene peat. The southern area is composed by residual clays -silt and coarse-grained soils to a lesser extent- linked to the dissolution of the Mesozoic substrate. Associated with these two types of deposits, two main aquifers can be differentiated. The thickness of the man-made deposits, fluvial-marine sediments and residual deposits was determined in this work. Thus, a 3-d model of Gijón subsurface at urban scale was obtained. A map of the Jurassic bedrock bedrock was also produced. Building construction works may be affected by the geotechnical behavior of the Quaternary deposits and the saturation of granular sediments., This is because the shallowness of the water table, the usual low bearing capacity and other issues such as clays consolidation or swelling phenomena. The use of concrete slabs, deep foundations and piled/anchored retaining walls is very common when projecting underground floors under these conditions.

Mechanisms of sulfate removal from subsurface calcium chloride brines: Heletz-Kokhav oilfields, Israel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gavrieli, I.; Starinsky, A.; Spiro, B.

1995-09-01

The evolution of the Ca-chloride brines in the Heletz Formation, Lower Cretaceous, in the southern coastal plain of Israel was reconstructed through the study of its sulfate concentration and isotopic composition. Particular emphasis was given to the brine-oil interaction in the oilfields and to the sulfate depletion and lower SO{sub 4}/Cl ratio in brines in contact with hydrocarbons (oil brines) relative to {open_quotes}oil-free{close_quotes} from dry wells in the same oilfields. A method is presented for a calculation of the amount of sulfate removed from the original seawater in the various stages of its evolution to Ca-chloride brine. Eastward migration ofmore » the Messinian Ca-Chloride brine into the Heletz Formation was accompanied by dolomitization of the country rock. Final depletion of sulfate from the brines took place, and possibly still occurs, in the presence of crude oil in the oilfields. The two oil-producing fields, Heletz and Kokhav, occupy different areas on a Rayleigh distillation diagram. Sulfate depletion in both fields is accompanied by an increase in {delta}{sup 34}S{sub SO}{sub 4}, which reaches a maximum values of 59{per_thousand}. The above correlation is explained by bacterial sulfate reduction facilitated by the contact with the crude. Samples collected from the same boreholes at time intervals of several months show two opposing trends: sulfate concentration decrease accompanied by increase in {delta}{sup 34}S{sub SO}{sub 4}, and vice versa. While the first can be explained as in situ bacterial sulfate reduction, the latter attest to subsurface brine migration, as would be expected in oil-producing fields.« less

Survival in the hot subsurface: Hydrogen stress on hyperthermophilic heterotrophs and methanogens

NASA Astrophysics Data System (ADS)

Topcuoglu, B. D.; Holden, J. F.

2017-12-01

Marine hyperthermophilic heterotrophs and methanogens belonging to the Thermococcales and Methanococcales are often found in hot subsurface environments such as hydrothermal vents, marine sediments, and oil reservoirs. This project aims to make fundamental advances in our understanding of interspecies microbe-microbe interactions in hot subsurface environments by integrating metabolic network modeling, transcriptomic analyses and continuous cultivation of hyperthermophiles and describe how heterotrophs and methanogens eliminate H2 stress. Some subsurface environments may lack alternative electron acceptors (e.g., S°) for the heterotroph and sufficient environmental flux rates to draw in fresh energy sources or remove excess metabolic products. We observed a decrease in growth rates for the H2-producer Thermococcus paralvinellae when grown with an aqueous H2 background of 65 µM relative to no added H2. Metabolite analysis showed increased formate production during H2 inhibition. Differential gene expression analyses coupled with metabolic network modeling showed that T. paralvinellae oxidized H2 and made formate by a formate hydrogenlyase to survive H2 inhibition. Low H2 concentrations (20 µM) also caused a decrease in growth and CH4 production rates for the H2-consuming methanogen Methanocaldococcus jannaschii. H2 stress in both organisms was ameliorated when the organisms were grown together syntrophically. CH4 was produced without any added H2 during syntrophic growth, and there was no formate produced by T. paralvinellae. These organisms may impact the biogeochemistry, especially natural gas production, in saline, organic-rich subsurface environments when both are present.

Formative Assessment Probes: Is It a Rock? Continuous Formative Assessment

ERIC Educational Resources Information Center

Keeley, Page

2013-01-01

A lesson plan is provided for a formative assessment probe entitled "Is It a Rock?" This probe is designed for teaching elementary school students about rocks through the use of a formative assessment classroom technique (FACT) known as the group Frayer Model. FACT activates students' thinking about a concept and can be used to…

Integrated loessite-paleokarst depositional system, early Pennsylvanian Molas Formation, Paradox Basin, southwestern Colorado, U.S.A.

NASA Astrophysics Data System (ADS)

Evans, James E.; Reed, Jason M.

2007-03-01

Mississippian paleokarst served as a dust trap for the oldest known Paleozoic loessite in North America. The early Pennsylvanian Molas Formation consists of loessite facies (sorted, angular, coarse-grained quartz siltstone), infiltration facies (loess redeposited as cave sediments within paleokarst features of the underlying Mississippian Leadville Limestone), colluvium facies (loess infiltrated into colluvium surrounding paleokarst towers) and fluvial facies (siltstone-rich, fluvial channel and floodplain deposits with paleosols). The depositional system evolved from an initial phase of infiltration and colluvium facies that were spatially and temporally related to the paleokarst surface, to loessite facies that mantled the paleotopography, and to fluvial facies that were intercalated with marine-deltaic rocks of the overlying Pennsylvanian Hermosa Formation. This sequence is interpreted as a response to the modification of the dust-trapping ability of the paleokarst surface. Loess was initially eroded from the surface, transported and redeposited in the subsurface by the karst paleohydrologic system, maintaining the dust-trapping ability of the paleotopographic surface. Later, the paleotopographic surface was buried when loess accumulation rates exceeded the transport capacity of the karst paleohydrologic system. These changes could have occurred because of (1) increased dust input rates in western Pangaea, (2) rising base levels and/or (3) porosity loss due to deposition within paleokarst passageways.

Correlation of coal beds in the Fruitland Formation as interpreted from geophysical logs, east-central San Juan County, New Mexico

USGS Publications Warehouse

Sandberg, Dorothy T.

1986-01-01

Correlation of coal beds in the Fruitland Formation (Upper Cretaceous) in the subsurface, from interpretation of geophysical logs, is an outgrowth of unpublished studies of deep coal on the Navajo Reservation by the author in the Toadlena 30 x 60 minute quadrangle, New Mexico, and by W. J. Mapel in the Farmington 30 x 60 minute quadrangle, New Mexico.  The lines of sections of this report extend eastward from the reservation into east-central San Juan County, which is in the western part of the San Juan Basin.  In this area, the rocks dip gently northeast toward the central part of the basin.  The thick coal is less than 1,500 feet beneath the surface.  Of the 53 logs in the sections, 48 are from oil- and gas-test holes, and 5 are from coal-test holes (see table 1).  Stratigraphic relations of the Upper Cretaceous Lewis Shale, Pictured Cliffs Sandstone, and Fruitland Formation, shown on the cross sections and briefly reviewed below, have been previously described for this or other parts of the San Juan Basin by Hayes and Zapp (1955), Beaumont (1971), Fassett and hinds (1971), O;Sullivan and other (1972), and Molenaar (1983), among others.

Origin of dolomitic rocks in the lower Permian Fengcheng formation, Junggar Basin, China: evidence from petrology and geochemistry

NASA Astrophysics Data System (ADS)

Zhu, Shifa; Qin, Yi; Liu, Xin; Wei, Chengjie; Zhu, Xiaomin; Zhang, Wei

2017-04-01

Although dolomitization of calcite minerals and carbonatization of volcanic rocks have been studied widely, the extensive dolomitic rocks that originated from altered volcanic and volcaniclastic rocks have not been reported. The dolomitic rocks of the Fengcheng Formation in the Junggar Basin of China appear to be formed under unusual geologic conditions. The petrological and geochemical characteristics indicate that the dolomitizing host rock is devitrified volcanic tuff. After low-temperature alteration and calcitization, these tuffaceous rocks are replaced by Mg-rich brine to form massive dolomitic tuffs. We propose that the briny (with -2 ‰ 6 ‰ of δ13CPDB and -5 ‰ 4 ‰ of δ18OPDB) and Mg-rich marine formation water (with 0.7060 0.7087 of 87Sr/86Sr ratio), the thick and intermediate-mafic volcanic ashes, and the tectonically compressional movement may have favored the formation of the unusual dolomitic rocks. We conclude that the proposed origin of the dolomitic rocks can be extrapolated to other similar terranes with volcaniclastic rocks, seabed tuffaceous sediment, and fracture filling of sill.

Stratigraphy, structure and regional correlation of eastern Blue Ridge sequences in southern Virginia and northwestern North Carolina: an interim report from new USGS mapping

USGS Publications Warehouse

Carter, Mark W.; Merschat, Arthur J.

2014-01-01

The contact between eastern Blue Ridge stratified rocks above Mesoproterozoic basement rocks is mostly faulted (Gossan Lead and Red Valley). The Callaway fault juxtaposes Ashe and Lynchburg rocks above Wills Ridge Formation. Alligator Back Formation rocks overlie Ashe and Lynchburg rocks along the Rock Castle Creek fault, which juxtaposes rocks of different metamorphism. The fault separates major structural domains: rocks with one penetrative foliation in the footwall, and pin-striped recrystallized compositional layering, superposed penetrative foliations, and cleavage characterize the hanging wall. These relationships are ambiguous along strike to the southwest, where the Ashe and Alligator Back formations are recrystallized at higher metamorphic grades.

Subsurface injection of liquid waste in Florida, United States of America

USGS Publications Warehouse

Vecchioli, John

1981-01-01

In 1979, liquid waste was injected into the subsurface of Florida by 10 injection systems at an aggregate average rate of 165,000 m3/d. All the systems inject into carbonate rocks that contain salty water. Extensive precautions are taken in the construction of the injection wells and in the monitoring of their operation to provide assurance that overlying and laterally contiguous freshwater resources do not become contaminated with either the injected waste or the saltwater displaced by the waste. Several concerns relating to the effectiveness of the confining bed above the injection zone for containing the injected wastes have arisen over the years. These concerns accentuate the value of a well-planned and implemented monitoring program from which one can evaluate the potential impact of waste injection on the subsurface environment.

Gas cluster ion beam for the characterization of organic materials in submarine basalts as Mars analogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sano, Naoko, E-mail: naoko.sano@ncl.ac.uk; Barlow, Anders J.; Cumpson, Peter J.

The solar system contains large quantities of organic compounds that can form complex molecular structures. The processing of organic compounds by biological systems leads to molecules with distinctive structural characteristics; thus, the detection and characterization of organic materials could lead to a high degree of confidence in the existence of extra-terrestrial life. Given the nature of the surface of most planetary bodies in the solar system, evidence of life is more likely to be found in the subsurface where conditions are more hospitable. Basalt is a common rock throughout the solar system and the primary rock type on Mars andmore » Earth. Basalt is therefore a rock type that subsurface life might exploit and as such a suitable material for the study of methods required to detect and analyze organic material in rock. Telluric basalts from Earth represent an analog for extra-terrestrial rocks where the indigenous organic matter could be analyzed for molecular biosignatures. This study focuses on organic matter in the basalt with the use of surface analysis techniques utilizing Ar gas cluster ion beams (GCIB); time of flight secondary ion mass spectrometry (ToF-SIMS), and x-ray photoelectron spectroscopy (XPS), to characterize organic molecules. Tetramethylammonium hydroxide (TMAH) thermochemolysis was also used to support the data obtained using the surface analysis techniques. The authors demonstrate that organic molecules were found to be heterogeneously distributed within rock textures. A positive correlation was observed to exist between the presence of microtubule textures in the basalt and the organic compounds detected. From the results herein, the authors propose that ToF-SIMS with an Ar GCIB is effective at detecting organic materials in such geological samples, and ToF-SIMS combined with XPS and TMAH thermochemolysis may be a useful approach in the study of extra-terrestrial organic material and life.« less

Lunar regolith stratigraphy analysis based on the simulation of lunar penetrating radar signals

NASA Astrophysics Data System (ADS)

Lai, Jialong; Xu, Yi; Zhang, Xiaoping; Tang, Zesheng

2017-11-01

The thickness of lunar regolith is an important index of evaluating the quantity of lunar resources such as 3He and relative geologic ages. Lunar penetrating radar (LPR) experiment of Chang'E-3 mission provided an opportunity of in situ lunar subsurface structure measurement in the northern mare imbrium area. However, prior work on analyzing LPR data obtained quite different conclusions of lunar regolith structure mainly because of the missing of clear interface reflectors in radar image. In this paper, we utilized finite-difference time-domain (FDTD) method and three models of regolith structures with different rock density, number of layers, shapes of interfaces, and etc. to simulate the LPR signals for the interpretation of radar image. The simulation results demonstrate that the scattering signals caused by numerous buried rocks in the regolith can mask the horizontal reflectors, and the die-out of radar echo does not indicate the bottom of lunar regolith layer and data processing such as migration method could recover some of the subsurface information but also result in fake signals. Based on analysis of simulation results, we conclude that LPR results uncover the subsurface layered structure containing the rework zone with multiple ejecta blankets of small crater, the ejecta blanket of Chang'E-3 crater, and the transition zone and estimate the thickness of the detected layer is about 3.25 m.

S-Wave Velocity Models Under the Saudi Arabian Portable Broadband Deployment: Evidence for Lithospheric Erosion Beneath the Arabian Shield

NASA Astrophysics Data System (ADS)

Julià, J.; Ammon, C. J.; Herrmann, R. B.

2002-12-01

Models of crustal evolution strongly rely on our knowledge on the mineralogical composition of subsurface rocks, as well as pressure and temperature conditions. Direct sampling of subsurface rocks is often not possible, so that constraints have to be placed from indirect estimates of rock properties. Detailed seismic imaging of subsurface rocks has the potential for providing such constraints, and probe the extent at depth of surface geologic observations. In this study, we provide detailed S-wave velocity profiles for the crust and uppermost mantle beneath the Saudi Arabian Portable Broadband Deployment stations. Seismic velocities have been estimated from the joint inversion of receiver functions and fundamental mode group velocities. Receiver functions are sensitive to S-wave velocity contrasts and vertical travel times, and surface-wave dispersion is sensitive to vertical S-wave velocity averages, so that their combination bridge resolution gaps associated with each individual data set. Our resulting models correlate well with surface geology observations in the Arabian Shield and characterize its terranes at depth: the Asir terrane consists of a 10-km thick upper crust of 3.3~km/s overlying a lower crust with shear-wave velocities of 3.7-3.8 km/s; the Afif terrane is made of a 20-km thick upper crust with average velocity of 3.6 km/s and a lower crust with a shear-velocity of about 3.8~km/s; the Nabitah mobile belt has a gradational, 15-km thick upper crust up to 3.6 km/s overlying a gradational lower crust with velocities up to 4.0 km/s. The crust-mantle transition is sharper in terranes of continental affinity and more gradational beneath terranes of oceanic affinity. In the uppermost mantle, our models suggest a thin lid between up to 50-60 km depth overlying a low velocity zone beneath station TAIF, located close to a region of upwelling mantle material. Temperatures in the lid are estimated to be about 1000 C, which are in good agreement with independent xenolith data, and suggest that the lithosphere could be eroded to a thickness as little as 50~km under this station.

A comparison of the rates of hydrocarbon generation from Lodgepole, False Bakken, and Bakken formation petroleum source rocks, Williston Basin, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarvie, D.M.; Elsinger, R.J.; Inden, R.F.

1996-06-01

Recent successes in the Lodgepole Waulsortian Mound play have resulted in the reevaluation of the Williston Basin petroleum systems. It has been postulated that hydrocarbons were generated from organic-rich Bakken Formation source rocks in the Williston Basin. However, Canadian geoscientists have indicated that the Lodgepole Formation is responsible for oil entrapped in Lodgepole Formation and other Madison traps in portions of the Canadian Williston Basin. Furthermore, geoscientists in the U.S. have recently shown oils from mid-Madison conventional reservoirs in the U.S. Williston Basin were not derived from Bakken Formation source rocks. Kinetic data showing the rate of hydrocarbon formation frommore » petroleum source rocks were measured on source rocks from the Lodgepole, False Bakken, and Bakken Formations. These results show a wide range of values in the rate of hydrocarbon generation. Oil prone facies within the Lodgepole Formation tend to generate hydrocarbons earlier than the oil prone facies in the Bakken Formation and mixed oil/gas prone and gas prone facies in the Lodgepole Formation. A comparison of these source rocks using a geological model of hydrocarbon generation reveals differences in the timing of generation and the required level of maturity to generate significant amounts of hydrocarbons.« less

Microbial Metabolic Roles in Bedrock Degradation and the Genesis of Biomineral and Biopattern Biosignatures in Caves and Mines

NASA Astrophysics Data System (ADS)

Boston, P. J.

2016-12-01

In subsurface environments like natural or anthropogenic caves (aka mines), microorganisms facilitate considerable bedrock degradation under a variety of circumstances. Mobilization of materials from these processes frequently produces distinctive biominerals, identifiable biotextures, and unique biopatterns. Microbial activities can even determine the form of speleothems (secondary mineral cave decorations), thus providing highly conspicuous macroscopic biosignatures. It is critical to understand microbial-mineral interactions, recognizing that while the lithology controls important aspects of the environment, in turn, the geochemistry is greatly affected by the biology. Microbial communities can contribute to the actual formation of cavities (speleogenesis), and subsequent enlargement of caves and vugs and the mineral deposits that enrich many subterranean spaces. A major challenge is to quantify such influences. Genetic analysis is revealing a vast but highly partitioned biodiversity in the overall rock fracture habitat of Earth's crust especially in caves and mines where the three phases of matter (solid rock, fluids, and gases) typically interact producing high niche richness. Lessons learned from the microbial/geochemical systems that we have studied include: 1) significant similarities in metabolic functions between different geochemical systems, 2) ubiquity of metal oxidation for energy, 3) ubiquity of biofilms, some highly mineralized, 4) highly interdependent, multi-species communities that can only transform materials in consortia, 5) complex ecological succession including characteristic pioneer species, 6) often very slow growth rates in culture, 7) prevalence of very small cell sizes, ( 100 - 500 nm diam.), 8) mineral reprecipitation of mobilized materials, often dependent on the presence of live microbial communities to produce initial amorphous compounds followed by gradual crystallization, and 9) resultant in situ self-fossilization. Microbial metabolism occurs against a complex backdrop of hydrology, geochemistry, and geological structures of subsurface environments. These are not static but change in response to both short term and much longer geological time scales thus presenting significant challenges in interpretation.

Detailed study of seismic wave attenuation from four oilfields in Abu Dhabi, United Arab Emirates

NASA Astrophysics Data System (ADS)

Bouchaala, F.; Ali, M. Y.; Matsushima, J.

2018-02-01

In the present study, we provide a detailed study of seismic wave attenuation obtained from four oilfields. The reservoir zones of these oilfields are complicated due to complex fracture networks, the presence of tar mat and high heterogeneity of carbonate rocks of which the subsurface of Abu Dhabi is mainly composed. These complexities decrease signal-to-noise ratio and make attenuation estimation difficult. We obtained high-resolution attenuation profiles from vertical seismic profiling (VSP) and sonic waveform data. The VSP data were recorded in all four oilfields and the sonic data were acquired in the reservoir zones of oilfields I and IV. We found that the VSP scattering attenuation ({Q}{{S}{{c}}{{a}}{{t}}}-1) varies from -0.080 to 0.180 over a depth range of 400-3500 m. We attributed this significant scattering to the high heterogeneity of carbonate rocks. The scattering profiles seem to be sensitive to fractures, lithology heterogeneity and tar mat, but their effect is superimposed. The VSP intrinsic attenuation varies from -0.15 to 0.246 with high variation within each formation. Since intrinsic attenuation is closely related to fluids, we assumed that this variation is due to the non-uniform distribution of fluids caused by the complex porosity network of the subsurface. The sonic monopole attenuation ({Q}{{M}{{f}}}-1) in the reservoir zones ranges between 0.033-0.094 and dipole inline attenuation ({Q}{{I}{{n}}{{l}}}-1) ranges from 0.040-0.138. The sonic attenuation appears to be sensitive to the presence of fluid and type of fractures, where it shows high attenuation for open fractures and low attenuation for resistive fractures. The zones with high clay content display high sonic intrinsic attenuation in the reservoir of oilfield II. We explain this by the frictional movement between the clay and carbonates due to the elasticity contrast of these two materials. Therefore, the solid grain friction may be the dominant attenuation mechanism in those zones.

Principal unconformities in Triassic and Jurassic rocks, western interior United States; a preliminary survey

USGS Publications Warehouse

Pipiringos, G.N.; O'Sullivan, Robert Brett

1978-01-01

The Triassic and Jurassic rocks in Western Interior United States contain nine unconformities each of which was destroyed to some extent by a younger unconformity. Regardless of extent, all are useful for correlation of rock sequences in areas where fossils or age dates are lacking. The purpose of this report is to call attention to the presence, significance, and value for correlation of these unconformities. The Triassic unconformities are designated from oldest to youngest, Tr-1, Tr-2, and Tr-3; the Jurassic ones similarly are designated J-0, J-l, J-2, J-3, J-4, and J-5. Of these, the J-2 surface is the best preserved and most widespread. It extends throughout the Western Interior and truncates the older unconformities in different parts of this area. Consequently, the J-2 surface is discussed and illustrated in much more detail than the others. Identification of these unconformities throughout large areas where their presence hitherto had been unknown results in some new unexpected correlations and conclusions. Principal among these are: (1) The Red Draw Member of the Jelm Formation of southeastern Wyoming equals the lower part of the Crow Mountain Sandstone of central Wyoming. The Sips Creek Member of the Jelm Formation of southeastern Wyoming equals the upper part of the Crow Mountain Sandstone of central Wyoming and the Gartra Member of the Chinle Formation in the Uinta Mountains of northeastern Utah and northwestern Colorado. The Chinle Formation of the Colorado Plateau and the Uinta Mountains equals the upper part of the Crow Mountain plus the Popo Agie Formation of central Wyoming. (2) The Nugget Sandstone of northern Utah and southwestern Wyoming approximately equals the Glen Canyon Group of the Colorado Plateau. The Temple Cap Sandstone of southwestern Utah equals the Gypsum Spring Formation and the Gypsum Spring Member of the Twin Creek Limestone of Wyoming and the Nesson Formation of Nordquist in the subsurface of the Williston basin. The Sawtooth and Piper Formations at their type sections in Montana and the lower parts of the Twin Creek Limestone (including only the Sliderock, Rich, and Boundary Ridge Members) in western Wyoming and of the Carmel Formation in the Colorado Plateau, at their respective type localities, are equivalent, but none of these correlate with any part of the Gypsum Spring Formation of Wyoming. The Curtis Formation at its type locality in the San Rafael Swell, Utah, equals only the lower part of the Curtis Formation of the Uinta Mountains. The upper part of the Curtis in the Uinta Mountains and the Redwater Shale Member of the Sundance Formation of Wyoming and South Dakota are equivalent. Estimates of the length of time in millions of years (m.y.) required for uplift and erosion of an unconformity range from less than 1 to as much as 10 m.y.; the average is about 1.8 m.y. if the extremes in time are excluded. The length of time for burial of the surfaces by transgression ranges from less than 1 to about 10 m.y.; the average is less than 1 m.y. if the extremes in time are disregarded.

Environmental Assessment, Change in C-17 Flight Training Operations at Grant County International Airport, Washington by Joint Base Lewis-McChord

DTIC Science & Technology

2011-10-01

ground (subsurface) deposits. Examples of prehistoric archaeological resources include village sites, campsites, lithic scatters, burials, hearths ...or hearth features), processing sites, caves and rock shelters, and petroglyph and pictograph sites. Examples of historic archaeological resources

Chapter 2: 2003 Geologic Assessment of Undiscovered Conventional Oil and Gas Resources in the Upper Cretaceous Navarro and Taylor Groups, Western Gulf Province, Texas

USGS Publications Warehouse

Condon, S.M.; Dyman, T.S.

2006-01-01

The Upper Cretaceous Navarro and Taylor Groups in the western part of the Western Gulf Province were assessed for undiscovered oil and gas resources in 2003. The area is part of the Smackover-Austin-Eagle Ford Composite Total Petroleum System. The rocks consist of, from youngest to oldest, the Escondido and Olmos Formations of the Navarro Group and the San Miguel Formation and the Anacacho Limestone of the Taylor Group (as well as the undivided Navarro Group and Taylor Group). Some units of the underlying Austin Group, including the 'Dale Limestone' (a term of local usage that describes a subsurface unit), were also part of the assessment in some areas. Within the total petroleum system, the primary source rocks comprise laminated carbonate mudstones and marine shales of the Upper Jurassic Smackover Formation, mixed carbonate and bioclastic deposits of the Upper Cretaceous Eagle Ford Group, and shelf carbonates of the Upper Cretaceous Austin Group. Possible secondary source rocks comprise the Upper Jurassic Bossier Shale and overlying shales within the Upper Jurassic to Lower Cretaceous Cotton Valley Group, Lower Cretaceous marine rocks, and the Upper Cretaceous Taylor Group. Oil and gas were generated in the total petroleum system at different times because of variations in depth of burial, geothermal gradient, lithology, and organic-matter composition. A burial-history reconstruction, based on data from one well in the eastern part of the study area (Jasper County, Tex.), indicated that (1) the Smackover generated oil from about 117 to 103 million years ago (Ma) and generated gas from about 52 to 41 Ma and (2) the Austin and Eagle Ford Groups generated oil from about 42 to 28 Ma and generated gas from about 14 Ma to the present. From the source rocks, oil and gas migrated upsection and updip along a pervasive system of faults and fractures as well as along bedding planes and within sandstone units. Types of traps include stratigraphic pinchouts, folds, faulted folds, and combinations of these. Seals consist of interbedded shales and mudstones and diagenetic cementation. The area assessed is divided into five assessment units (AUs): (1) Travis Volcanic Mounds Oil (AU 50470201), (2) Uvalde Volcanic Mounds Gas and Oil (AU 50470202), (3) Navarro-Taylor Updip Oil and Gas (AU 50470203), (4) Navarro-Taylor Downdip Gas and Oil (AU 50470204), and (5) Navarro-Taylor Slope-Basin Gas (AU 50470205). Total estimated mean undiscovered conventional resources in the five assessment units combined are 33.22 million barrels of oil, 1,682.80 billion cubic feet of natural gas, and 34.26 million barrels of natural gas liquids.

Absorption spectroscopic studies of Np(IV) complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reed, D. T.

2004-01-01

The complexation of neptunium (IV) with selected inorganic and organic ligands was studied as part of an investigation to establish key subsurface interactions between neptunium and biological systems. The prevalence of reducing environments in most subsurface migation scenarios, which are in many cases induced by biological activity, has increased the role and importance of Np(IV) as a key subsurface neptunium oxidation state. The biodegradation of larger organics that often coexist with actinides in the subsurface leads to the formation of many organic acids as transient products that, by complexation, play a key role in defining the fate and speciation ofmore » neptunium in biologically active systems. These often compete with inorganic complexes e.g. hydrolysis and phosphate. Herein we report the results of a series of complexation studies based on new band formation of the characteristic 960 nm band for Np(IV). Formation constants for Np(IV) complexes with phosphate, hydrolysis, succinate, acetohydroxamic acid, and acetate were determined. These results show the 960 nm absorption band to be very amenable to these types of complexation studies.« less

Carbon Sequestration in Unconventional Reservoirs: Geophysical, Geochemical and Geomechanical Considerations

NASA Astrophysics Data System (ADS)

Zakharova, Natalia V.

In the face of the environmental challenges presented by the acceleration of global warming, carbon capture and storage, also called carbon sequestration, may provide a vital option to reduce anthropogenic carbon dioxide emissions, while meeting the world's energy demands. To operate on a global scale, carbon sequestration would require thousands of geologic repositories that could accommodate billions of tons of carbon dioxide per year. In order to reach such capacity, various types of geologic reservoirs should be considered, including unconventional reservoirs such as volcanic rocks, fractured formations, and moderate-permeability aquifers. Unconventional reservoirs, however, are characterized by complex pore structure, high heterogeneity, and intricate feedbacks between physical, chemical and mechanical processes, and their capacity to securely store carbon emissions needs to be confirmed. In this dissertation, I present my contribution toward the understanding of geophysical, geochemical, hydraulic, and geomechanical properties of continental basalts and fractured sedimentary formations in the context of their carbon storage capacity. The data come from two characterization projects, in the Columbia River Flood Basalt in Washington and the Newark Rift Basin in New York, funded by the U.S. Department of Energy through Big Sky Carbon Sequestration Partnerships and TriCarb Consortium for Carbon Sequestration. My work focuses on in situ analysis using borehole geophysical measurements that allow for detailed characterization of formation properties on the reservoir scale and under nearly unaltered subsurface conditions. The immobilization of injected CO2 by mineralization in basaltic rocks offers a critical advantage over sedimentary reservoirs for long-term CO2 storage. Continental flood basalts, such as the Columbia River Basalt Group, possess a suitable structure for CO2 storage, with extensive reservoirs in the interflow zones separated by massive impermeable basalt in flow interiors. Other large igneous provinces and ocean floor basalts could accommodate centuries' worth of world's CO2 emissions. Low-volume basaltic flows and fractured intrusives may potentially serve as smaller-scale CO2 storage targets. However, as illustrated by the example of the Palisade sill in the Newark basin, even densely fractured intrusive basalts are often impermeable, and instead may serve as caprock for underlying formations. Hydraulic properties of fractured formations are very site-specific, but observations and theory suggest that the majority of fractures at depth remain closed. Hydraulic tests in the northern Newark basin indicate that fractures introduce strong anisotropy and heterogeneity to the formation properties, and very few of them augment hydraulic conductivity of these fractured formations. Overall, they are unlikely to provide enough storage capacity for safe CO 2 injection at large scales, but can be suitable for small-scale controlled experiments and pilot injection tests. The risk of inducing earthquakes by underground injection has emerged as one of the primary concerns for large-scale carbon sequestration, especially in fractured and moderately permeable formations. Analysis of in situ stress and distribution of fractures in the subsurface are important steps for evaluating the risks of induced seismicity. Preliminary results from the Newark basin suggest that local stress perturbation may potentially create favorable stress conditions for CO2 sequestration by allowing a considerable pore pressure increase without carrying large risks of fault reactivation. Additional in situ stress data are needed, however, to accurately constrain the magnitude of the minimum horizontal stress, and it is recommended that such tests be conducted at all potential CO 2 storage sites.

Non-ferromagnetic overburden casing

DOEpatents

Vinegar, Harold J.; Harris, Christopher Kelvin; Mason, Stanley Leroy

2010-09-14

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one system for electrically insulating an overburden portion of a heater wellbore is described. The system may include a heater wellbore located in a subsurface formation and an electrically insulating casing located in the overburden portion of the heater wellbore. The casing may include at least one non-ferromagnetic material such that ferromagnetic effects are inhibited in the casing.

Evidence of biological activity in Hawaiian subsurface basalts

NASA Astrophysics Data System (ADS)

Fisk, M. R.; Storrie-Lombardi, M. C.; Douglas, S.; Popa, R.; McDonald, G.; di Meo-Savoie, C.

2003-12-01

The Hawaii Scientific Drilling Program (HSDP) cored and recovered igneous rock from the surface to a depth of 3109 m near Hilo, Hawaii. Much of the deeper parts of the hole is composed of hyaloclastite (fractured basalt glass that has been cemented in situ with secondary minerals). Some hyaloclastite units have been altered in a manner attributed to microorganisms in volcanic rocks. Samples from one such unit (1336 m to 1404 m below sea level) were examined to test the hypothesis that the alteration was associated with microorganisms. Deep ultraviolet native fluorescence and resonance Raman spectroscopy indicate that nucleic acids and aromatic amino acids are present in clay inside spherical cavities (vesicles) within basalt glass. Chemical mapping shows that phosphorus and carbon were enriched at the boundary between the clay and volcanic glass of the vesicles. Environmental scanning electron microscopy (ESEM) reveals two to three micrometer coccoid structures in these same boundaries. ESEM-linked energy dispersive spectroscopy demonstrated carbon, phosphorous, chloride, and magnesium in these bodies significantly differing from unoccupied neighboring regions of basalt. These observations taken together indicate the presence of microorganisms at the boundary between primary volcanic glass and secondary clays. Amino acids and nucleic acids were extracted from bulk samples of the hyaloclastite unit. Amino acid abundance was low, and if the amino acids are derived from microorganisms in the rock, then there are less than 100,000 cells per gram of rock. Most nucleic acid sequences extracted from the unit were closely related to sequences of Crenarchaeota collected from the subsurface of the ocean floor.

Preliminary evaluation of the shale gas prospectivity of the Lower Cretaceous Pearsall Formation in the onshore Gulf Coast region, United States

USGS Publications Warehouse

Enomoto, Catherine B.; Scott, Kristina; Valentine, Brett J.; Hackley, Paul C.; Dennen, Kristin; Lohr, Celeste D.

2012-01-01

Recent work by the U.S. Geological Survey indicated that the Lower Cretaceous Pearsall Formation contains an estimated mean undiscovered, technically recoverable unconventional gas resource of 8.8 trillion cubic ft in the Maverick Basin, South Texas. Cumulative gas production from horizontal wells in the core area of the emerging play has exceeded 5 billion cubic ft since 2008. However, very little information is available to characterize the Pearsall Formation as an unconventional gas resource beyond the Maverick Basin in the greater Gulf Coast region. Therefore, this reconnaissance study examines spatial distribution, thickness, organic richness and thermal maturity of the Pearsall Formation in the onshore U.S. Gulf states using wireline logs and drill cuttings sample analysis. Spontaneous potential and resistivity curves of approximately forty wireline logs from wells in five Gulf Coast states were correlated to ascertain the thickness of the Pearsall Formation and delineate its three members: Pine Island Shale, James Limestone or Cow Creek Limestone, and Bexar Shale, in ascending stratigraphic order. In Florida and Alabama the Pearsall Formation is up to about 300 ft thick; in Mississippi, Louisiana, Arkansas, and East Texas, thickness is up to as much as 800 ft. Drill cuttings sampled from 11 wells at depths ranging from 4600 to 19,600 feet subsurface indicate increasingly oxygenated depositional environments (predominance of red shale) towards the eastern part of the basin. Cuttings vary widely in lithology but indicate interbedded clastics and limestones throughout the Pearsall Formation, consistent with previous regional studies. Organic petrographic and geochemical analyses of 17 cutting samples in the Pearsall Formation indicate a wide range in thermal maturity, from immature (0.43% Ro [vitrinite reflectance]) in paleo-high structural locations to the peak oil window (0.99% Ro) in the eastern portion of the Gulf Coast Basin. This is in contrast to dry gas thermal maturity throughout the Pearsall Formation in the South Texas Maverick Basin. Organic carbon content is low overall, even in immature samples, with a range of 0.17 to 1.08 wt.% by Leco in 22 Pearsall Formation samples. The pyrolysis output range was 0.23 to 2.33 mg hydrocarbon/g rock. The thermal maturity and Rock-Eval pyrolysis data and organic petrologic observations from this study will be used to better focus specific areas of investigation where the Pearsall Formation may be prospective as an unconventional hydrocarbon source and reservoir.

Salt deposits in Los Medanos area, Eddy and Lea counties, New Mexico

USGS Publications Warehouse

Jones, C.L.; with sections on Ground water hydrology, Cooley; and Surficial Geology, Bachman

1973-01-01

The salt deposits of Los Medanos area, in Eddy and Lea Counties, southeastern New Mexico, are being considered for possible use as a receptacle for radioactive wastes in a pilot-plant repository. The salt deposits of the area. are in three evaporite formations: the Castile, Salado, and Rustler Formations, in ascending order. The three formations are dominantly anhydrite and rock salt, but some gypsum, potassium ores, carbonate rock, and fine-grained clastic rocks are present. They have combined thicknesses of slightly more than 4,000 feet, of which roughly one-half belongs to the Salado. Both the Castile and the Rustler are-richer in anhydrite-and poorer in rock salt-than the Salado, and they provide this salt-rich formation with considerable Protection from any fluids which might be present in underlying or overlying rocks. The Salado Formation contains many thick seams of rock salt at moderate depths below the surface. The rock salt has a substantial cover of well-consolidated rocks, and it is very little deformed structurally. Certain geological details essential for Waste-storage purposes are unknown or poorly known, and additional study involving drilling is required to identify seams of rock salt suitable for storage purposes and to establish critical details of their chemistry, stratigraphy, and structure.

Testing the Injectivity of CO2 in a Sub-surface Heterogeneous Reservoir

NASA Astrophysics Data System (ADS)

Sundal, A.; Nystuen, J.; Dypvik, H.; Aagaard, P.

2011-12-01

This case study on subsurface reservoir characterization, considers the effect of geological heterogeneities on the storage capacity and injectivity of the Johansen Formation, which is a deep, saline aquifer underlying the Troll Gas Field off the Norwegian coast. The Johansen Formation has been interpreted as a sandy, prograding unit, deposited in a shallow marine environment during Early Jurassic time, and is overlain by a shaly unit; the Amundsen Formation. It appears as a wedge shaped sandstone body, up to 140m thick, with an areal extent in the order of 10 000 km2. The Johansen Formation is currently being considered for large scale CO2 storage from two gas power plants situated on the west coast of Norway, both of which will operate with full scale CO2 handling, as proposed by Norwegian authorities. The storage capacity needed is in the order of 3 Mt CO2/year. With access to a new 3D seismic survey (Gassnova, 2010), and based on existing well log data from 25 penetrating wells, we have studied large scale geometries and intra-formational features, and built a geo-conceptual model of the Johansen Formation. The reservoir is heterogeneous, with distinct permeability zonation within clinothems separated by less permeable layers. In order to obtain better understanding of crucial reservoir parameters and supplement limited data, comparison of data from easily accessible analogue rock units is useful. For this purpose the unit should be well exposed and thoroughly documented, such as the Panther Tongue Member (Star Point Formation, Mesa Verde Group) in Book Cliffs, from which we have collected some comparable permeability estimates for the model. On a micro scale, mineralogy, grain size/shape and pore geometry constitue major controls on reservoir porosity and permeability. Direct geological information is at this point in time limited to a few meters of core, from which detailed mineralogical information has been derived (optical microscopy, SEM, XRD), and some additional data from side wall cores and cuttings. From this we evaluate facies dependence related to observed diagenetic features and compositional variations due to burial depth (2-4km), mainly considering chlorite coatings (preserving porosity) and cementation (calcite and quartz). Using Schlumberger soft-wares; Petrel (reservoir) and Eclipse (fluid flow), we are testing injection scenarios (one point, several points, bleeding wells) in several intra-formational geological settings. These results will be evaluated relative to the distribution of facies and heterogeneities in the reservoir, considering multiphase flow given the local pressure regime.

Gravity and magnetic study of the Pahute Mesa and Oasis Valley region, Nye County, Nevada

USGS Publications Warehouse

Mankinen, Edward A.; Hildenbrand, Thomas G.; Dixon, Gary L.; McKee, Edwin H.; Fridrich, Christopher J.; Laczniak, Randell J.

1999-01-01

Regional gravity and aeromagnetic maps reveal the existence of deep basins underlying much of the southwestern Nevada volcanic field, approximately 150 km northwest of Las Vegas. These maps also indicate the presence of prominent features (geophysical lineaments) within and beneath the basin fill. Detailed gravity surveys were conducted in order to characterize the nature of the basin boundaries, delineate additional subsurface features, and evaluate their possible influence on the movement of ground-water. Geophysical modeling of gravity and aeromagnetic data indicates that many of the features may be related to processes of caldera formation. Collapse of the various calderas within the volcanic field resulted in dense basement rocks occurring at greater depths within caldera boundaries. Modeling indicates that collapse occurred along faults that are arcuate and steeply dipping. There are indications that the basement in the western Pahute Mesa - Oasis Valley region consists predominantly of granitic and/or fine-grained siliceous sedimentary rocks that may be less permeable to groundwater flow than the predominantly fractured carbonate rock basement to the east and southeast of the study area. The northeast-trending Thirsty Canyon lineament, expressed on gravity and basin thickness maps, separates dense volcanic rocks on the northwest from less dense intracaldera accumulations in the Silent Canyon and Timber Mountain caldera complexes. The source of the lineament is an approximately 2-km wide ring fracture system with step-like differential displacements, perhaps localized on a pre-existing northeast-trending Basin and Range fault. Due to vertical offsets, the Thirsty Canyon fault zone probably juxtaposes rock types of different permeability and, thus, it may act as a barrier to ground-water flow and deflect flow from Pahute Mesa along its flanks toward Oasis Valley. Within the Thirsty Canyon fault zone, highly fractured rocks may serve also as a conduit, depending upon the degree of alteration and its effect on porosity and permeability. In the Oasis Valley region, other structures that may influence ground-water flow include the western and southern boundaries of the Oasis Valley basin, where the basement abruptly shallows.

Recent experimental data may point to a greater role for osmotic pressures in the subsurface

USGS Publications Warehouse

Neuzil, C.E.; Provost, A.M.

2009-01-01

Uncertainty about the origin of anomalous fluid pressures in certain geologic settings has caused researchers to take a second look at osmosis, or flow driven by chemical potential differences, as a pressure‐generating process in the subsurface. Interest in geological osmosis has also increased because of an in situ experiment by Neuzil (2000) suggesting that Pierre Shale could generate large osmotic pressures when highly compacted. In the last few years, additional laboratory and in situ experiments have greatly increased the number of data on osmotic properties of argillaceous formations, but they have not been systematically examined. In this paper we compile these data and explore their implications for osmotic pressure generation in subsurface systems. Rather than base our analysis on osmotic efficiencies, which depend strongly on concentration, we calculated values of a quantity we term osmotic specific surface area (Aso) that, in principle, is a property of the porous medium only. The Aso values are consistent with a surprisingly broad spectrum of osmotic behavior in argillaceous formations, and all the formations tested exhibited at least a modest ability to generate osmotic pressure. It appears possible that under appropriate conditions some formations can be highly effective osmotic membranes able to generate osmotic pressures exceeding 30 MPa (3 km of head) at porosities as high as ∼0.1 and pressures exceeding 10 MPa at porosities as high as ∼0.2. These findings are difficult to reconcile with the lack of compelling field evidence for osmotic pressures, and we propose three explanations for the disparity: (1) Our analysis is flawed and argillaceous formations are less effective osmotic membranes than it suggests; (2) the necessary subsurface conditions, significant salinity differences within intact argillaceous formations, are rare; or (3) osmotic pressures are unlikely to be detected and are not recognized when encountered. The last possibility, that osmotic pressures routinely escape detection or are attributed to other mechanisms, has important implications for understanding subsurface flow regimes.

Rho kinase inhibition drives megakaryocyte polyploidization and proplatelet formation through MYC and NFE2 downregulation.

PubMed

Avanzi, Mauro P; Goldberg, Francine; Davila, Jennifer; Langhi, Dante; Chiattone, Carlos; Mitchell, William Beau

2014-03-01

The processes of megakaryocyte polyploidization and demarcation membrane system (DMS) formation are crucial for platelet production, but the mechanisms controlling these processes are not fully determined. Inhibition of Rho kinase (ROCK) signalling leads to increased polyploidization in umbilical cord blood-derived megakaryocytes. To extend these findings we determined the effect of ROCK inhibition on development of the DMS and on proplatelet formation. The underlying mechanisms were explored by analysing the effect of ROCK inhibition on the expression of MYC and NFE2, which encode two transcription factors critical for megakaryocyte development. ROCK inhibition promoted DMS formation, and increased proplatelet formation and platelet release. Rho kinase inhibition also downregulated MYC and NFE2 expression in mature megakaryocytes, and this down-regulation correlated with increased proplatelet formation. Our findings suggest a model whereby ROCK inhibition drives polyploidization, DMS growth and proplatelet formation late in megakaryocyte maturation through downregulation of MYC and NFE2 expression. © 2014 John Wiley & Sons Ltd.

Multistage hydrothermal silicification and Fe-Tl-As-Sb-Ge-REE enrichment in the Red Dog Zn-Pb-Ag district, northern Alaska: Geochemistry, origin, and exploration applications

USGS Publications Warehouse

Slack, J.F.; Kelley, K.D.; Anderson, V.M.; Clark, J.L.; Ayuso, R.A.

2004-01-01

Geochemical analyses of major, trace, and rare earth elements (REE) in more than 200 samples of variably silicified and altered wall rocks, massive and banded sulfide, silica rock, and sulfide-rich and unmineralized barite were obtained from the Main, Aqqaluk, and Anarraaq deposits in the Red Dog Zn-Pb-Ag district of northern Alaska. Detailed lithogeochemical profiles for two drill cores at Aqqaluk display an antithetic relationship between SiO2/Al2O3 and TiO2/Zr which, together with textural information, suggest preferential silicification of carbonate-bearing sediments. Data for both drill cores also show generally high Tl, Sb, As, and Ge and uniformly positive Eu anomalies (Eu/Eu* > 1.0). Similar high Tl, Sb, As, Ge, and Eu/Eu* values are present in the footwall and shallow hanging wall of Zn-Pb-Ag sulfide intervals at Anarraaq but are not as widely dispersed. Net chemical changes for altered wall rocks in the district, on the basis of average Al-normalized data relative to unaltered black shales of the host Kuna Formation, include large enrichments (>50%) of Fe, Ba, Eu, V, S, Co, Zn, Pb, Tl, As, Sb, and Ge at both Red Dog and Anarraaq, Si at Red Dog, and Sr, U, and Se at Anarraaq. Large depletions (>50%) are evident for Ca at both Red Dog and Anarraaq, for Mg, P, and Y at Red Dog, and for Na at Anarraaq. At both Red Dog and Anarraaq, wall-rock alteration removed calcite and minor dolomite during hydrothermal decarbonation reactions and introduced Si, Eu, and Ge during silicification. Sulfidation reactions deposited Fe, S, Co, Zn, Pb, Tl, As, and Sb; barite mineralization introduced Ba, S, and Sr. Light REE and U were mobilized locally. This alteration and mineralization occurred during Mississippi an hydrothermal events that predated the Middle Jurassic-Cretaceous Brookian orogeny. Early hydrothermal silicification at Red Dog took place prior to or during massive sulfide mineralization, on the basis of the dominantly planar nature of Zn-Pb veins, which suggests filling of fractures that developed in previously lithified rock. Uniformly low Ca and Mg and uniformly negative Ce anomalies in highly siliceous Red Dog wall rocks reflect hydrothermal decarbonation reactions and pervasive silicification owing to conductive cooling of oxidized metalliferous fluids. Similar Ca and Mg depletions are evident at Anarraaq but generally lack associated silicification, possibly because temperatures of the hydrothermal fluids were too low (<180??C) or because the thermal contrast between the fluids and wall rocks was smaller owing to the greater depth of alteration and mineralization there, compared with Red Dog. Chalcophile element anomalies (Fe, Zn, Pb, Tl, As, Sb) in wall rocks at both Red Dog and Anarraq are attributed to sulfidation reactions, coeval with subsurface Zn-Pb-Ag mineralization, during the mixing of oxidized metalliferous fluids with H2S-rich fluids derived locally within the Kuna Formation. Sedimentary wall rocks in the Red Dog district are characterized by a distinctive suite of geochemical anomalies, especially for Zn, Pb, Tl, As, Sb, Ge, and Eu/Eu*. At the Aqqaluk deposit, wall rocks without visible sphalerite or galena (<300 ppm Zn + Pb) have anomalous Eu/Eu*, Tl, Sb, and As for up to ???100 m stratigraphically below Zn-rich silica rock. At Anarraaq, the Tl anomaly is most extensively developed, and enrichment relative to unaltered black shale of the Kuna Formation is present up to 62 m above the highest Zn-Pb sulfide zones. The magnitude of the enrichment and systematic behavior of Tl in the district make Tl a promising geochemical exploration guide for Red Dog-type Zn-Pb-Ag deposits elsewhere. ?? 2004 by Economic Geology.

30 CFR 250.1601 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... means a well drilled through cap rock into the core at a salt dome for the purpose of producing brine. Cap rock means the rock formation, a body of limestone, anhydride, and/or gypsum, overlying a salt dome. Sulphur deposit means a formation of rock that contains elemental sulphur. Sulphur production...

30 CFR 250.1601 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... means a well drilled through cap rock into the core at a salt dome for the purpose of producing brine. Cap rock means the rock formation, a body of limestone, anhydride, and/or gypsum, overlying a salt dome. Sulphur deposit means a formation of rock that contains elemental sulphur. Sulphur production...

Active-Passive Microwave Remote Sensing of Martian Permafrost and Subsurface Water

NASA Technical Reports Server (NTRS)

Raizer, V.; Linkin, V. M.; Ozorovich, Y. R.; Smythe, W. D.; Zoubkov, B.; Babkin, F.

2000-01-01

The investigation of permafrost formation global distribution and their appearance in h less than or equal 1 m thick subsurface layer would be investigated successfully by employment of active-passive microwave remote sensing techniques.

The Effect of Boiling on Seismic Properties of Water-Saturated Fractured Rock

NASA Astrophysics Data System (ADS)

Grab, Melchior; Quintal, Beatriz; Caspari, Eva; Deuber, Claudia; Maurer, Hansruedi; Greenhalgh, Stewart

2017-11-01

Seismic campaigns for exploring geothermal systems aim at detecting permeable formations in the subsurface and evaluating the energy state of the pore fluids. High-enthalpy geothermal resources are known to contain fluids ranging from liquid water up to liquid-vapor mixtures in regions where boiling occurs and, ultimately, to vapor-dominated fluids, for instance, if hot parts of the reservoir get depressurized during production. In this study, we implement the properties of single- and two-phase fluids into a numerical poroelastic model to compute frequency-dependent seismic velocities and attenuation factors of a fractured rock as a function of fluid state. Fluid properties are computed while considering that thermodynamic interaction between the fluid phases takes place. This leads to frequency-dependent fluid properties and fluid internal attenuation. As shown in a first example, if the fluid contains very small amounts of vapor, fluid internal attenuation is of similar magnitude as attenuation in fractured rock due to other mechanisms. In a second example, seismic properties of a fractured geothermal reservoir with spatially varying fluid properties are calculated. Using the resulting seismic properties as an input model, the seismic response of the reservoir is then computed while the hydrothermal structure is assumed to vary over time. The resulting seismograms demonstrate that anomalies in the seismic response due to fluid state variability are small compared to variations caused by geological background heterogeneity. However, the hydrothermal structure in the reservoir can be delineated from amplitude anomalies when the variations due to geology can be ruled out such as in time-lapse experiments.

Geologic influence on induced seismicity: Constraints from potential field data in Oklahoma

USGS Publications Warehouse

Shah, Anjana K.; Keller, G. Randy

2017-01-01

Recent Oklahoma seismicity shows a regional correlation with increased wastewater injection activity, but local variations suggest that some areas are more likely to exhibit induced seismicity than others. We combine geophysical and drill hole data to map subsurface geologic features in the crystalline basement, where most earthquakes are occurring, and examine probable contributing factors. We find that most earthquakes are located where the crystalline basement is likely composed of fractured intrusive or metamorphic rock. Areas with extrusive rock or thick (>4 km) sedimentary cover exhibit little seismicity, even in high injection rate areas, similar to deep sedimentary basins in Michigan and western North Dakota. These differences in seismicity may be due to variations in permeability structure: within intrusive rocks, fluids can become narrowly focused in fractures and faults, causing an increase in local pore fluid pressure, whereas more distributed pore space in sedimentary and extrusive rocks may relax pore fluid pressure.

The Potential Role of Formate for Synthesis and Life in Serpentinization Systems

NASA Astrophysics Data System (ADS)

Lang, S. Q.; Frueh-Green, G. L.; Bernasconi, S. M.; Brazelton, W. J.; McGonigle, J. M.

2016-12-01

The high hydrogen concentrations produced during water-rock serpentinization reactions provide abundant thermodynamic energy that can drive the synthesis of organic compounds both biotically and abiotically. We investigated the synthesis of abiotic carbon and the metabolic pathways of the microbial inhabitants of the high energy but low diversity serpentinite-hosted Lost City Hydrothermal Field. High concentrations of the organic acid formate can be attributed to two sources. In some locations formate lacks detectable 14C, demonstrating it was formed abiotically from mantle-derived CO2. In other locations there is an additional modern contribution to the formate pool, potentially indicating active cycling with modern seawater dissolved inorganic carbon by microorganisms. The presence of this carbon source is likely critical for the survival of the subsurface microbial communities that inhabit alkaline serpentinization environments, where inorganic carbon is severely limited. Archaeal lipids produced by the Lost City Methanosarcinales (LCMS) also largely lack 14C, requiring their carbon source to be similarly 14C-free. Metagenomic evidence suggests that the LCMS could use formate for methanogenesis and, altogether, the data suggests that these organisms cannot rely on inorganic carbon as their carbon source and substrate for methanogenesis. Considering the lack of dissolved inorganic carbon in this system, the ability to utilize formate may have been a key evolutionary adaptation for survival in serpentinite-hosted environments. In the Lost City system, the LCMS apparently rely upon an abiotically produced organic carbon source, which may enable the Lost City microbial ecosystem to survive in the absence of photosynthesis or its byproducts.

Geologic Map of the Edwards Aquifer In Northern Medina and Northeastern Uvalde Counties, South-central Texas

USGS Publications Warehouse

Clark, Allan K.; Faith, Jason R.; Blome, Charles D.; Pedraza, Diana E.

2006-01-01

The southern segment of the Edwards aquifer in south-central Texas is one of the most productive subsurface reservoirs of potable water in the world, providing water of excellent quality to more than a million people in the San Antonio region, where the Environmental Protection Agency (EPA) has declared it to be a sole-source aquifer (van der Leeden and others, 1990). Depending on the depositional province within which the associated carbonate rocks originated (Maclay and Small, 1984), the Edwards aquifer is composed of several geologic formations (primarily limestone and dolostone) of Early Cretaceous age. Most water pumped from the Edwards aquifer comes form the Person and Kainer Formations, which were deposited over the San Marcos Platform. The principal source of ground water in study area is the Devils River Formation, which was deposited in the Devils River trend. The Devils River Formation provides large quantities of irrigation water to fertile bottomland areas of Medina and Uvalde Counties, where the success of farming and ranching activities has long depended upon water from the Edwards aquifer. The study area includes all of the Edwards aquifer recharge zone between the Sabinal River (on the west) and the Medina River (on the east) plus an updip fringe of the confined zone in east-central Uvalde and central Medina Counties. Over about ninety percent of the study area--within the Devils River trend--the Edwards aquifer is composed of the Georgetown Formation plus the underlying Devils River Formation. Over the remaining area--over the southwestern margin of the San Marcos platform--the Edwards aquifer consists of the Georgetown Formation plus the underlying Edwards Group (Rose, 1972), which comprises the Kainer and Person Formations.

Trends and future challenges in sampling the deep terrestrial biosphere.

PubMed

Wilkins, Michael J; Daly, Rebecca A; Mouser, Paula J; Trexler, Ryan; Sharma, Shihka; Cole, David R; Wrighton, Kelly C; Biddle, Jennifer F; Denis, Elizabeth H; Fredrickson, Jim K; Kieft, Thomas L; Onstott, Tullis C; Peterson, Lee; Pfiffner, Susan M; Phelps, Tommy J; Schrenk, Matthew O

2014-01-01

Research in the deep terrestrial biosphere is driven by interest in novel biodiversity and metabolisms, biogeochemical cycling, and the impact of human activities on this ecosystem. As this interest continues to grow, it is important to ensure that when subsurface investigations are proposed, materials recovered from the subsurface are sampled and preserved in an appropriate manner to limit contamination and ensure preservation of accurate microbial, geochemical, and mineralogical signatures. On February 20th, 2014, a workshop on "Trends and Future Challenges in Sampling The Deep Subsurface" was coordinated in Columbus, Ohio by The Ohio State University and West Virginia University faculty, and sponsored by The Ohio State University and the Sloan Foundation's Deep Carbon Observatory. The workshop aims were to identify and develop best practices for the collection, preservation, and analysis of terrestrial deep rock samples. This document summarizes the information shared during this workshop.

Rock-Eval pyrolysis and vitrinite reflectance results from the Sheep Creek 1 well, Susitna basin, south-central Alaska

USGS Publications Warehouse

Stanley, Richard G.; Lillis, Paul G.; Pawlewicz, Mark J.; Haeussler, Peter J.

2014-01-01

We used Rock-Eval pyrolysis and vitrinite reflectance to examine the petroleum source potential of rock samples from the Sheep Creek 1 well in the Susitna basin of south-central Alaska. The results show that Miocene nonmarine coal, carbonaceous shale, and mudstone are potential sources of hydrocarbons and are thermally immature with respect to the oil window. In the samples that we studied, coals are more organic-rich and more oil-prone than carbonaceous shales and silty mudstones, which appear to be potential sources of natural gas. Lithologically similar rocks may be present in the deeper parts of the subsurface Susitna basin located west of the Sheep Creek 1 well, where they may have been buried deeply enough to generate oil and (or) gas. The Susitna basin is sparsely drilled and mostly unexplored, and no commercial production of hydrocarbons has been obtained. However, the existence of potential source rocks of oil and gas, as shown by our Rock-Eval results, suggests that undiscovered petroleum accumulations may be present in the Susitna basin.

Modeling groundwater flow and quality

USGS Publications Warehouse

Konikow, Leonard F.; Glynn, Pierre D.; Selinus, Olle

2013-01-01

In most areas, rocks in the subsurface are saturated with water at relatively shallow depths. The top of the saturated zone—the water table—typically occurs anywhere from just below land surface to hundreds of feet below the land surface. Groundwater generally fills all pore spaces below the water table and is part of a continuous dynamic flow system, in which the fluid is moving at velocities ranging from feet per millennia to feet per day (Fig. 33.1). While the water is in close contact with the surfaces of various minerals in the rock material, geochemical interactions between the water and the rock can affect the chemical quality of the water, including pH, dissolved solids composition, and trace-elements content. Thus, flowing groundwater is a major mechanism for the transport of chemicals from buried rocks to the accessible environment, as well as a major pathway from rocks to human exposure and consumption. Because the mineral composition of rocks is highly variable, as is the solubility of various minerals, the human-health effects of groundwater consumption will be highly variable.

3D Sedimentological and geophysical studies of clastic reservoir analogs: Facies architecture, reservoir properties, and flow behavior within delta front facies elements of the Cretaceous Wall Creek Member, Frontier Formation, Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christopher D. White

2009-12-21

Significant volumes of oil and gas occur in reservoirs formed by ancient river deltas. This has implications for the spatial distribution of rock types and the variation of transport properties. A between mudstones and sandstones may form baffles that influence productivity and recovery efficiency. Diagenetic processes such as compaction, dissolution, and cementation can also alter flow properties. A better understanding of these properties and improved methods will allow improved reservoir development planning and increased recovery of oil and gas from deltaic reservoirs. Surface exposures of ancient deltaic rocks provide a high-resolution view of variability. Insights gleaned from these exposures canmore » be used to model analogous reservoirs, for which data is sparser. The Frontier Formation in central Wyoming provides an opportunity for high-resolution models. The same rocks exposed in the Tisdale anticline are productive in nearby oil fields. Kilometers of exposure are accessible, and bedding-plane exposures allow use of high-resolution ground-penetrating radar. This study combined geologic interpretations, maps, vertical sections, core data, and ground-penetrating radar to construct geostatistical and flow models. Strata-conforming grids were use to reproduce the observed geometries. A new Bayesian method integrates outcrop, core, and radar amplitude and phase data. The proposed method propagates measurement uncertainty and yields an ensemble of plausible models for calcite concretions. These concretions affect flow significantly. Models which integrate more have different flow responses from simpler models, as demonstrated an exhaustive two-dimensional reference image and in three dimensions. This method is simple to implement within widely available geostatistics packages. Significant volumes of oil and gas occur in reservoirs that are inferred to have been formed by ancient river deltas. This geologic setting has implications for the spatial distribution of rock types (\\Eg sandstones and mudstones) and the variation of transport properties (\\Eg permeability and porosity) within bodies of a particular rock type. Both basin-wide processes such as sea-level change and the autocyclicity of deltaic processes commonly cause deltaic reservoirs to have large variability in rock properties; in particular, alternations between mudstones and sandstones may form baffles and trends in rock body permeability can influence productivity and recovery efficiency. In addition, diagenetic processes such as compaction, dissolution, and cementation can alter the spatial pattern of flow properties. A better understanding of these properties, and improved methods to model the properties and their effects, will allow improved reservoir development planning and increased recovery of oil and gas from deltaic reservoirs. Surface exposures of ancient deltaic rocks provide a high resolution, low uncertainty view of subsurface variability. Patterns and insights gleaned from these exposures can be used to model analogous reservoirs, for which data is much sparser. This approach is particularly attractive when reservoir formations are exposed at the surface. The Frontier Formation in central Wyoming provides an opportunity for high resolution characterization. The same rocks exposed in the vicinity of the Tisdale anticline are productive in nearby oil fields, including Salt Creek. Many kilometers of good-quality exposure are accessible, and the common bedding-plane exposures allow use of shallow-penetration, high-resolution electromagnetic methods known as ground-penetrating radar. This study combined geologic interpretations, maps, vertical sections, core data, and ground-penetrating radar to construct high-resolution geostatistical and flow models for the Wall Creek Member of the Frontier Formation. Stratal-conforming grids were use to reproduce the progradational and aggradational geometries observed in outcrop and radar data. A new, Bayesian method integrates outcrop--derived statistics, core observations of concretions, and radar amplitude and phase data. The proposed method consistently propagates measurement uncertainty through the model-building process, and yields an ensemble of plausible models for diagenetic calcite concretions. These concretions have a statistically significant on flow. Furthermore, neither geostatistical data from the outcrops nor geophysical data from radar is sufficient: models which integrate these data have significantly different flow responses. This was demonstrated both for an exhaustive two-dimensional reference image and in three dimensions, using flow simulations. This project wholly supported one PhD student and part of the education of an additional MS and PhD student. It helped to sponsor 6 refereed articles and 8 conference or similar presentations.« less

Proof-of-feasibility of using well bore deformation as a diagnostic tool to improve CO 2 sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murdoch, Larry; Moysey, Stephen; Germanovich, Leonid

Injecting CO 2 raises pore pressure and this causes subsurface formations to deform. The pattern and amount of deformation will reflect the distribution of pressure and formation properties in the subsurface, two quantities of interest during CO 2 storage. The hypothesis underlying this research is that the small deformation accompanying CO 2 storage can be measured and interpreted to improve the storage process.

Subsurface Investigation using 2D Resistivity and Ground Penetrating Radar at Teluk Kumbar, Penang

NASA Astrophysics Data System (ADS)

Teoh, YJ; Bruka, MA; Idris, NM; Ismail, NA; Muztaza, NM

2018-04-01

The objective of this study is to determine the structure and condition of the subsurface by using 2D resistivity and Ground Penetrating Radar (GPR) methods. The study was conducted at SK Sungai Batu, Teluk Kumbar, Penang Island. For 2D resistivity method, Wenner-Schlumberger array was used while for GPR, 250 MHz antenna was used at the site. The survey consists of 200m length survey line. GPR result shows that there is high intensity of EM. 2D resistivity result shows that the low resistivity region (200 Ωm to 340 Ωm) appears to be at the centre of the survey line from depth 7 m to 13 m. Meanwhile, the higher resistivity region (4000 Ωm to 6000 Ωm) may indicate the bedrock structure of the subsurface, which is the granitic rock. This region is bedrock which rested at depth 14 m and below. In conclusion, data obtained from GPR and 2D resistivity methods can be easily correlated to determine the features of the subsurface.

Mars Exploration Rover surface operations: driving spirit at Gusev Crater

NASA Technical Reports Server (NTRS)

Leger, Chris; Trebi-Ollennu, Ashitey; Wright, John; Maxwell, Scott; Bonitz, Bob; Biesiadecki, Jeff; Hartman, Frank; Cooper, Brian; Baumgartner, Eric; Maimone, Mark

2005-01-01

Spirit is one of two rovers, that landed on Mars in January 2004 as part of NASA's Mars Exploration Rovers mission. Since then, Spirit has traveled over 4 kilometers accross the Martian surface while investigating rocks and soils, digging trenches to examine the subsurface environment, and climbing hills to reach outcrops of bedrock.

The Qtracer2 Program for Tracer-Breakthrough Curve Analysis for Tracer Tests in Karstic Aquifers and Other Hydrologic Systems (2002)

EPA Science Inventory

Tracer testing is generally regarded as the most reliable and efficient method of gathering surface and subsurface hydraulic information. This is especially true for karstic and fractured-rock aquifers. Qualitative tracing tests have been conventionally employed in most karst s...

Application of seismic-refraction techniques to hydrologic studies

USGS Publications Warehouse

Haeni, F.P.

1986-01-01

During the past 30 years, seismic-refraction methods have been used extensively in petroleum, mineral, and engineering investigations, and to some extent for hydrologic applications. Recent advances in equipment, sound sources, and computer interpretation techniques make seismic refraction a highly effective and economical means of obtaining subsurface data in hydrologic studies. Aquifers that can be defined by one or more high seismic-velocity surfaces, such as (1) alluvial or glacial deposits in consolidated rock valleys, (2) limestone or sandstone underlain by metamorphic or igneous rock, or (3) saturated unconsolidated deposits overlain by unsaturated unconsolidated deposits,are ideally suited for applying seismic-refraction methods. These methods allow the economical collection of subsurface data, provide the basis for more efficient collection of data by test drilling or aquifer tests, and result in improved hydrologic studies.This manual briefly reviews the basics of seismic-refraction theory and principles. It emphasizes the use of this technique in hydrologic investigations and describes the planning, equipment, field procedures, and intrepretation techniques needed for this type of study.Examples of the use of seismic-refraction techniques in a wide variety of hydrologic studies are presented.

Application of seismic-refraction techniques to hydrologic studies

USGS Publications Warehouse

Haeni, F.P.

1988-01-01

During the past 30 years, seismic-refraction methods have been used extensively in petroleum, mineral, and engineering investigations and to some extent for hydrologic applications. Recent advances in equipment, sound sources, and computer interpretation techniques make seismic refraction a highly effective and economical means of obtaining subsurface data in hydrologic studies. Aquifers that can be defined by one or more high-seismic-velocity surface, such as (1) alluvial or glacial deposits in consolidated rock valleys, (2) limestone or sandstone underlain by metamorphic or igneous rock, or (3) saturated unconsolidated deposits overlain by unsaturated unconsolidated deposits, are ideally suited for seismic-refraction methods. These methods allow economical collection of subsurface data, provide the basis for more efficient collection of data by test drilling or aquifer tests, and result in improved hydrologic studies. This manual briefly reviews the basics of seismic-refraction theory and principles. It emphasizes the use of these techniques in hydrologic investigations and describes the planning, equipment, field procedures, and interpretation techniques needed for this type of study. Further-more, examples of the use of seismic-refraction techniques in a wide variety of hydrologic studies are presented.

Seasonal GPR Signal Changes in Two Contrasting Soils in the Shale Hills Catchment

NASA Astrophysics Data System (ADS)

Lin, H.; Zhang, J.; Doolittle, J. A.

2011-12-01

Repeated GPR surveys in different seasons, combined with real-time soil water monitoring, provide a useful methodology to reveal subsurface hydrologic processes and their underlying mechanisms in different soils and hillslopes. This was demonstrated in the Shale Hills Critical Zone Observatory using two contrasting soils over several dry and wet seasons. Our results showed that 1) the radar reflection in the BC-C horizon interface in the deep Rushtown soil became clearer as soil became wetter, which was linked to lateral flow above this horizon interface that increased the contrast, and 2) the reflection in the soil-bedrock interface and the weathered-unweathered rock interface in the shallow Weikert soil become intermittent as soil became wetter, which was attributed to non-uniform distribution of water in bedrock fractures that created locally strong contrast, leading to point scatter of GPR reflection. This study shows the optimal time for using GPR to detect soil horizon interfaces, the value of nondestructive mapping of soil-rock moisture distribution patterns, and the possibility of identifying preferential flow pathways in the subsurface.

Estimation of Deeper Structure at the Soultz Hot Dry Rock Field by Means of Reflection Method Using 3C AE as Wave Source

NASA Astrophysics Data System (ADS)

Soma, N.; Niitsuma, H.; Baria, R.

1997-12-01

We investigate the deep subsurface structure below the artificial reservoir at the Soultz Hot Dry Rock (HDR) site in France by a reflection method which uses acoustic emission (AE) as a wave source. In this method, we can detect reflected waves by examining the linearity of a three-dimensional hodogram. Additionally for imaging a deep subsurface structure, we employ a three-dimensional inversion with a restriction of wave polarization angles and with a compensation for a heterogeneous source distribution.¶We analyzed 101 AE wave forms observed at the Soultz site during the hydraulic testing in 1993. Some deep reflectors were revealed by this method. The bottom of the artificial reservoir that is presumed from all of the AE locations in 1993 was delineated at the depth of about 3900 m as a reflector. Other deeper reflectors were detected below the reservoir, which would not have been detected using conventional methods. Furthermore these reflectors agreed with the results of the tri-axial drill-bit VSP (Asanuma et al., 1996).

The Collins Creek and Pleasant Creek Formations: Two new upper cretaceous subsurface units in the Carolina/Georgia Coastal Plain

USGS Publications Warehouse

,; Prowell, D.C.; Christopher, R.A.

2004-01-01

This paper formally defines two new Upper Cretaceous subsurface units in the southern Atlantic Coastal Plain of North Carolina, South Carolina and Georgia: the Collins Creek Formation and the Pleasant Creek Formation. These units are confined to the subsurface of the outer Coastal Plain, and their type sections are established in corehole CHN-820 from Charleston County, S.C. The Collins Creek Formation consists of greenish-gray lignitic sand and dark-greenish-gray sandy clay and is documented in cores from Allendale, Beaufort, Berkeley, Dorchester, Jasper and Marion Counties, South Carolina, and from Screven County, Georgia. Previously, Collins Creek strata had been incorrectly assigned to the Middendorf Formation. These sediments occupy a stratigraphic position between the Turonian/Coniacian Cape Fear Formation (?) below and the proposed upper Coniacian to middle Santonian Pleasant Creek Formation above. The Collins Creek Formation is middle and late Coniacian in age on the basis of calcareous nannofossil and palynomorph analyses. The Pleasant Creek Formation consists of olive-gray sand and dark-greenish-gray silty to sandy clay and is documented in cores from New Hanover County, North Carolina, and Berkeley, Charleston, Dorchester, Horry and Marion Counties, South Carolina. The strata of this unit previously were assigned incorrectly to the Middendorf Formation and (or) the Cape Fear Formation. These sediments occupy a stratigraphic position between the proposed Collins Creek Formation below and the Shepherd Grove Formation above. The Pleasant Creek Formation is late Coniacian and middle Santonian in age, on the basis of its calcareous nannofossil and palynomorph assemblages.

Growth rate characteristics of acidophilic heterotrophic organisms from mine waste rock piles

NASA Astrophysics Data System (ADS)

Yacob, T. W.; Silverstein, J.; Jenkins, J.; Andre, B. J.; Rajaram, H.

2010-12-01

Autotrophic iron oxidizing bacteria play a key role in pyrite oxidation and generation of acid mine drainage AMD. Scarcity of organic substrates in many disturbed sites insures that IOB have sufficient oxygen and other nutrients for growth. It is proposed that addition of organic carbon substrate to waste rock piles will result in enrichment of heterotrophic microorganisms limiting the role of IOB in AMD generation. Previous researchers have used the acidophilic heterotroph Acidiphilium cryptum as a model to study the effects of organic substrate addition on the pyrite oxidation/AMD cycle. In order to develop a quantitative model of effects such as competition for oxygen, it is necessary to use growth and substrate consumption rate expressions, and one approach is to choose a model strain such as A. cryptum for kinetic studies. However we have found that the growth rate characteristics of A. cryptum may not provide an accurate model of the remediation effects of organic addition to subsurface mined sites. Fluorescent in-situ hybridization (FISH) assays of extracts of mine waste rock enriched with glucose and yeast extract did not produce countable numbers of cells in the Acidiphilium genus, with a detection limit of3 x 104 cells/gram rock, despite evidence of the presence of well established heterotrophic organisms. However, an MPN enrichment produced heterotrophic population estimates of 1x107 and 1x109 cells/gram rock. Growth rate studies of A. cryptum showed that cultures took 120 hours to degrade 50% of an initial glucose concentration of 2,000 mg/L. However a mixed culture enriched from mine waste rock consumed 100% of the same amount of glucose in 24 hours. Substrate consumption data for the mixed culture were fit to a Monod growth model: {dS}/{dt} = μ_{max}S {( {X_0}/{Y} + S_0 -S )}/{(K_s +S)} Kinetic parameters were estimated utilizing a non linear regression method coupled with an ODE solver. The maximum specific growth rate of the mixed population with μ max was calculated to be 0.13 hr-1 and a yield of 0.52 g cells/g glucose and Ks of 0.2 g/L glucose. The effect of pH on growth was compared for A. cryptum and the mixed population. It was found that the mixed culture had a higher tolerance for extremely low pH conditions, with no growth at pH = 1; whereas no growth of A cryptum was observed at pH = 1.5. Both A. cryptum and the mixed cultures grew within a pH range of 2.5 - 6. A phospholipid fatty acid analysis (PLFA) of the mixed culture indicated that both eukaryotic and prokaryotic organisms are present at a ratio of approximately 1:1, indicating that organisms such as fungi may be important in carbon cycling in these acidic subsurface formations. The results from this research show that utilization of mixed wild cultures for environmental modeling may yield better results than selection of a single strain to represent populations in a quantitative model.

Crystal structure of laser-induced subsurface modifications in Si

NASA Astrophysics Data System (ADS)

Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.; Haberl, B.; Bradby, J. E.; Williams, J. S.; Huis in't Veld, A. J.

2015-08-01

Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this work, we investigate the geometry and crystal structure of laser-induced subsurface modifications in monocrystalline silicon wafers. In addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si -iii/Si -xii occur as a result of the laser irradiation.

Exploring Subsurface Geology Using Radar Techniques: Experiments in Sahara and Consequences for Mars Exploration

NASA Astrophysics Data System (ADS)

Paillou, P.; Grandjean, G.; Heggy, E.; Farr, T.

2004-05-01

For several years, we have conducted a quantitative study of radar penetration performances in various desert arid environments. This study combines both SAR (Synthetic Aperture Radar) imaging from orbital and airborne platforms and in situ GPR (Ground Penetrating Radar) measurements. Laboratory characterization of various minerals and rocks are used as input to electromagnetic models such as IEM (Integral Equation Model) and FDTD (Finite Difference Time Domain) that describe the subsurface scattering process for inversion purposes. Several test sites were explored, mainly the Sahara. Our first experiment was realized in Republic of Djibouti, an arid volcanic area which is a good analog to Mars. We observed a very little radar penetration there because of the presence of iron oxides and salts in the subsurface that make the soil conductive [Paillou et al., GRL, 2001]. A more favorable site for radar penetration was then explored in southern Egypt: the Bir Safsaf area where buried river channels were discovered using orbital SAR images. We showed how to combine SAR and GPR in order to obtain a complete description of subsurface geology down to several meters [Paillou et al., IEEE TGRS, 2003]. Such field experiments were the basis for more systematic laboratory measurements of the electromagnetic properties of various rocks and minerals which were used in numerical models in order to simulate the performances of future Martian radars, e.g. MARSIS and NETLANDER low frequency radars [Heggy et al., Icarus, 2001; Berthelier et al., JGR, 2003; Heggy et al., JGR, 2003]. More recently, new explorations were conducted in Mauritania in order to demonstrate radar capacities for geologic mapping [Grandjean et al., Coll. Afr. Geol., 2004] and in Libya where radar discovered a double impact crater in the southern desert [Paillou et al., C.R. Geoscience, 2003]. More local radar experiments were also conducted on a test site located in France, the Pyla sand dune, where we observed and modeled a radar signature of subsurface water [Grandjean et al., IEEE TGRS, 2001; Paillou et al., IGARSS'03, 2003]. All of these results shall be used in the context of "terrestrial analogs to Mars" studies in order to prepare for future Mars exploration using radars [Farr et al., Planet. Dec. Study, 2002; Paillou et al., 35th LPSC, 2004]: it concerns both GPR instruments onboard rovers and landers devoted to the exploration of the deep subsurface [Berthelier at al., ESA Pasteur, 2003] and SAR imaging systems onboard orbital platforms for global mapping of the shallow subsurface geology [Paillou et al., Conf. Water Mars, 2001].

A 3-D wellbore simulator (WELLTHER-SIM) to determine the thermal diffusivity of rock-formations

NASA Astrophysics Data System (ADS)

Wong-Loya, J. A.; Santoyo, E.; Andaverde, J.

2017-06-01

Acquiring thermophysical properties of rock-formations in geothermal systems is an essential task required for the well drilling and completion. Wellbore thermal simulators require such properties for predicting the thermal behavior of a wellbore and the formation under drilling and shut-in conditions. The estimation of static formation temperatures also needs the use of these properties for the wellbore and formation materials (drilling fluids and pipes, cements, casings, and rocks). A numerical simulator (WELLTHER-SIM) has been developed for modeling the drilling fluid circulation and shut-in processes of geothermal wellbores, and for the in-situ determination of thermal diffusivities of rocks. Bottomhole temperatures logged under shut-in conditions (BHTm), and thermophysical and transport properties of drilling fluids were used as main input data. To model the thermal disturbance and recovery processes in the wellbore and rock-formation, initial drilling fluid and static formation temperatures were used as initial and boundary conditions. WELLTHER-SIM uses these temperatures together with an initial thermal diffusivity for the rock-formation to solve the governing equations of the heat transfer model. WELLTHER-SIM was programmed using the finite volume technique to solve the heat conduction equations under 3-D and transient conditions. Thermal diffusivities of rock-formations were inversely computed by using an iterative and efficient numerical simulation, where simulated thermal recovery data sets (BHTs) were statistically compared with those temperature measurements (BHTm) logged in some geothermal wellbores. The simulator was validated using a well-documented case reported in the literature, where the thermophysical properties of the rock-formation are known with accuracy. The new numerical simulator has been successfully applied to two wellbores drilled in geothermal fields of Japan and Mexico. Details of the physical conceptual model, the numerical algorithm, and the validation and application results are outlined in this work.

Extraction of remanent magnetization from magnetization vector inversions of airborne full tensor magnetic gradiometry data

NASA Astrophysics Data System (ADS)

Queitsch, M.; Schiffler, M.; Stolz, R.; Meyer, M.; Kukowski, N.

2017-12-01

Measurements of the Earth's magnetic field are one of the most used methods in geophysical exploration. The ambiguity of the method, especially during modeling and inversion of magnetic field data sets, is one of its biggest challenges. Additional directional information, e.g. gathered by gradiometer systems based on Superconducting Quantum Interference Devices (SQUIDs), will positively influence the inversion results and will thus lead to better subsurface magnetization models. This is especially beneficial, regarding the shape and direction of magnetized structures, especially when a significant remanent magnetization of the underlying sources is present. The possibility to separate induced and remanent contributions to the total magnetization may in future also open up advanced ways for geological interpretation of the data, e.g. a first estimation of diagenesis processes. In this study we present the results of airborne full tensor magnetic gradiometry (FTMG) surveys conducted over a dolerite intrusion in central Germany and the results of two magnetization vector inversions (MVI) of the FTMG and a conventional total field anomaly data set. A separation of the two main contributions of the acquired total magnetization will be compared with information of the rock magnetization measured on orientated rock samples. The FTMG inversion results show a much better agreement in direction and strength of both total and remanent magnetization compared to the inversion using only total field anomaly data. To enhance the separation process, the application of additional geophysical methods, i.e. frequency domain electromagnetics (FDEM), in order to gather spatial information of subsurface rock susceptibility will also be discussed. In this approach, we try to extract not only information on subsurface conductivity but also the induced magnetization. Using the total magnetization from the FTMG data and the induced magnetization from the FDEM data, the full separation of induced and remanent magnetization should be enabled. First results this approach will be shown and discussed.

Delving into the Deep Biosphere

NASA Astrophysics Data System (ADS)

Grim, S. L.; Sogin, M. L.; Boetius, A.; Briggs, B. R.; Brazelton, W. J.; D'Hondt, S. L.; Edwards, K. J.; Fisk, M. R.; Gaidos, E.; Gralnick, J.; Hinrichs, K.; Lazar, C.; Lavalleur, H.; Lever, M. A.; Marteinsson, V.; Moser, D. P.; Orcutt, B.; Pedersen, K.; Popa, R.; Ramette, A.; Schrenk, M. O.; Sylvan, J. B.; Smith, A. R.; Teske, A.; Walsh, E. A.; Colwell, F. S.

2013-12-01

The Census of Deep Life organized an international survey of microbial community diversity in terrestrial and marine deep subsurface environments. Habitats included subsurface continental fractured rock aquifers, volcanic and metamorphic subseafloor sedimentary units from the open ocean, subsurface oxic and anoxic sediments and underlying basaltic oceanic crust, and their overlying water columns. Our survey employed high-throughput pyrosequencing of the hypervariable V4-V6 16S rRNA gene of bacteria and archaea. We detected 1292 bacterial genera representing 40 phyla, and 99 archaeal genera from 30 phyla. Of these, a core group of thirteen bacterial genera occurred in every environment. A genus of the South African Goldmine Group (Euryarchaeota) was always present whenever archaea were detected. Members of the rare biosphere in one system often represented highly abundant taxa in other environments. Dispersal could account for this observation but mechanisms of transport remain elusive. Ralstonia (Betaproteobacteria) represented highly abundant taxa in marine communities and terrestrial rock, but generally low abundance organisms in groundwater. Some of these taxa could represent sample contamination, and their extensive distribution in several systems requires further assessment. An unknown Sphingobacteriales (Bacteroidetes) genus, Stenotrophomonas (Gammaproteobacteria), Acidovorax and Aquabacterium (both Betaproteobacteria), a Chlorobiales genus, and a TM7 genus were in the core group as well but more prevalent in terrestrial environments. Similarly, Bacillus (Firmicutes), a new cyanobacterial genus, Bradyrhizobium and Sphingomonas (both Alphaproteobacteria), a novel Acidobacteriaceae genus, and Variovorax (Betaproteobacteria) frequently occurred in marine systems but represented low abundance taxa in other environments. Communities tended to cluster by biome and material, and many genera were unique to systems. For example, certain Rhizobiales (Alphaproteobacteria) only occurred in groundwater, and select Firmicutes and actinobacterial taxa were specific to rock environments. We continue to investigate the ecological and physiological context of these organisms. By combining deep sequencing of microbial communities and geochemical and physical evaluations of their environments, we bring to light the diversity and scope of the deep biosphere and insight into the factors that determine the nature of these communities.

Geophysical characterization of Range-Front Faults, Snake Valley, Nevada

USGS Publications Warehouse

Asch, Theodore H.; Sweetkind, Donald S.

2010-01-01

In September 2009, the U.S. Geological Survey, in cooperation with the National Park Service, collected audiomagnetotelluric (AMT) data along two profiles on the eastern flank of the Snake Range near Great Basin National Park to refine understanding of the subsurface geology. Line 1 was collected along Baker Creek, was approximately 6.7-km long, and recorded subsurface geologic conditions to approximately 800-m deep. Line 2, collected farther to the southeast in the vicinity of Kious Spring, was 2.8-km long, and imaged to depths of approximately 600 m. The two AMT lines are similar in their electrical response and are interpreted to show generally similar subsurface geologic conditions. The geophysical response seen on both lines may be described by three general domains of electrical response: (1) a shallow (mostly less than 100-200-m deep) domain of highly variable resistivity, (2) a deep domain characterized by generally high resistivity that gradually declines eastward to lower resistivity with a steeply dipping grain or fabric, and (3) an eastern domain in which the resistivity character changes abruptly at all depths from that in the western domain. The shallow, highly variable domain is interpreted to be the result of a heterogeneous assemblage of Miocene conglomerate and incorporated megabreccia blocks overlying a shallowly eastward-dipping southern Snake Range detachment fault. The deep domain of generally higher resistivity is interpreted as Paleozoic sedimentary rocks (Pole Canyon limestone and Prospect Mountain Quartzite) and Mesozoic and Cenozoic plutonic rocks occurring beneath the detachment surface. The range of resistivity values within this deep domain may result from fracturing adjacent to the detachment, the presence of Paleozoic rock units of variable resistivities that do not crop out in the vicinity of the lines, or both. The eastern geophysical domain is interpreted to be a section of Miocene strata at depth, overlain by Quaternary alluvial fill. These deposits lie east of a steeply east-dipping normal fault that cuts all units and has about 100 m of east-side-down offset.

Sub-crop geologic map of pre-Tertiary rocks in the Yucca Flat and northern Frenchman Flat areas, Nevada Test Site, southern Nevada

USGS Publications Warehouse

Cole, James C.; Harris, Anita G.; Wahl, Ronald R.

1997-01-01

This map displays interpreted structural and stratigraphic relations among the Paleozoic and older rocks of the Nevada Test Site region beneath the Miocene volcanic rocks and younger alluvium in the Yucca Flat and northern Frenchman Flat basins. These interpretations are based on a comprehensive examination and review of data for more than 77 drillholes that penetrated part of the pre-Tertiary basement beneath these post-middle Miocene structural basins. Biostratigraphic data from conodont fossils were newly obtained for 31 of these holes, and a thorough review of all prior microfossil paleontologic data is incorporated in the analysis. Subsurface relationships are interpreted in light of a revised regional geologic framework synthesized from detailed geologic mapping in the ranges surrounding Yucca Flat, from comprehensive stratigraphic studies in the region, and from additional detailed field studies on and around the Nevada Test Site.All available data indicate the subsurface geology of Yucca Flat is considerably more complicated than previous interpretations have suggested. The western part of the basin, in particular, is underlain by relics of the eastward-vergent Belted Range thrust system that are folded back toward the west and thrust by local, west-vergent contractional structures of the CP thrust system. Field evidence from the ranges surrounding the north end of Yucca Flat indicate that two significant strike-slip faults track southward beneath the post-middle Miocene basin fill, but their subsurface traces cannot be closely defined from the available evidence. In contrast, the eastern part of the Yucca Flat basin is interpreted to be underlain by a fairly simple north-trending, broad syncline in the pre-Tertiary units. Far fewer data are available for the northern Frenchman Flat basin, but regional analysis indicates the pre- Tertiary structure there should also be relatively simple and not affected by thrusting.This new interpretation has implications for ground water flow through pre-Tertiary rocks beneath the Yucca Flat and northern Frenchman Flat areas, and has consequences for ground water modeling and model validation. Our data indicate that the Mississippian Chainman Shale is not a laterally extensive confining unit in the western part of the basin because it is folded back onto itself by the convergent structures of the Belted Range and CP thrust systems. Early and Middle Paleozoic limestone and dolomite are present beneath most of both basins and, regardless of structural complications, are interpreted to form a laterally continuous and extensive carbonate aquifer. Structural culmination that marks the French Peak accommodation zone along the topographic divide between the two basins provides a lateral pathway through highly fractured rock between the volcanic aquifers of Yucca Flat and the regional carbonate aquifer. This pathway may accelerate the migration of ground-water contaminants introduced by underground nuclear testing toward discharge areas beyond the Nevada Test Site boundaries. Predictive three-dimensional models of hydrostratigraphic units and ground-water flow in the pre-Tertiary rocks of subsurface Yucca Flat are likely to be unrealistic due to the extreme structural complexities. The interpretation of hydrologic and geochemical data obtained from monitoring wells will be difficult to extrapolate through the flow system until more is known about the continuity of hydrostratigraphic units.

Pits Formation from Volatile Outgassing on 67P/Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Mousis, O.; Guilbert-Lepoutre, A.; Brugger, B.; Jorda, L.; Kargel, J. S.; Bouquet, A.; Auger, A.-T.; Lamy, P.; Vernazza, P.; Thomas, N.; Sierks, H.

2015-11-01

We investigate the thermal evolution of comet 67P/Churyumov-Gerasimenko’s subsurface in the Seth_01 region, where active pits have been observed by the ESA/Rosetta mission. Our simulations show that clathrate destabilization and amorphous ice crystallization can occur at depths corresponding to those of the observed pits in a timescale shorter than 67P/Churyumov-Gerasimenko’s lifetime in the comet’s activity zone in the inner solar system. Sublimation of crystalline ice down to such depths is possible only in the absence of a dust mantle, which requires the presence of dust grains in the matrix small enough to be dragged out by gas from the pores. Our results are consistent with both pits formation via sinkholes or subsequent to outbursts, the dominant process depending on the status of the subsurface porosity. A sealed dust mantle would favor episodic and disruptive outgassing as a result of increasing gas pressure in the pores, while high porosity should allow the formation of large voids in the subsurface due to the continuous escape of volatiles. We finally conclude that the subsurface of 67P/Churyumov-Gerasimenko is not uniform at a spatial scale of ˜100-200 m.

Wilcox group (Paleocene to Eocene) coals of the Sabine Uplift area, Texas and Louisiana

USGS Publications Warehouse

Hook, Robert W.; Warwick, Peter D.; SanFilipo, John R.; Warwick, Peter D.; Karlsen, Alexander K.; Merrill, Matthew D.; Valentine, Brett J.

2011-01-01

The Wilcox Group (Paleocene to Eocene) of the Sabine uplift, a structural arch in northeastern Texas and northwestern Louisiana (Figure 1), has lignite zones that approach subbituminous rank (see Chapter 4, this publication). These coals are among the highest quality resources known within the Gulf Coastal Plain because of their low ash yield and sulfur content. The surface expression of the Sabine uplift is defined by the contact between coal-bearing rocks of the Wilcox Group and overlying fluvial rocks of the Carrizo Sand, which is the basal unit of the Claiborne Group (Figures 2, 3). The Sabine uplift study area includes parts of Harrison, Marion, Nacogdoches, Panola, Rusk, Sabine, San Augustine, and Shelby Counties in Texas and Bossier, Caddo, De Soto, Natchitoches, Red River, and Sabine Parishes in Louisiana (Figure 1). Adjacent counties and parishes that include the subsurface Wilcox Group extend the regional Sabine uplift area. The Wilcox in the subsurface is underlain by the Midway Group (Figure 3), a mudstone-dominated marine sequence of Paleocene age. Quaternary alluvium and terrace deposits overlying the Wilcox Group at the surface are limited to areas of modern drainage.The total thickness of the Wilcox Group within the Sabine uplift area ranges from approximately 400 ft on outcrop to 2500 ft in subsurface (Kaiser, 1990). In a few places, the contact between the overlying Carrizo Sand and Wilcox Group is erosional, but in other places, the contact is gradational.

TOUGH2Biot - A simulator for coupled thermal-hydrodynamic-mechanical processes in subsurface flow systems: Application to CO2 geological storage and geothermal development

NASA Astrophysics Data System (ADS)

Lei, Hongwu; Xu, Tianfu; Jin, Guangrong

2015-04-01

Coupled thermal-hydrodynamic-mechanical processes have become increasingly important in studying the issues affecting subsurface flow systems, such as CO2 sequestration in deep saline aquifers and geothermal development. In this study, a mechanical module based on the extended Biot consolidation model was developed and incorporated into the well-established thermal-hydrodynamic simulator TOUGH2, resulting in an integrated numerical THM simulation program TOUGH2Biot. A finite element method was employed to discretize space for rock mechanical calculation and the Mohr-Coulomb failure criterion was used to determine if the rock undergoes shear-slip failure. Mechanics is partly coupled with the thermal-hydrodynamic processes and gives feedback to flow through stress-dependent porosity and permeability. TOUGH2Biot was verified against analytical solutions for the 1D Terzaghi consolidation and cooling-induced subsidence. TOUGH2Biot was applied to evaluate the thermal, hydrodynamic, and mechanical responses of CO2 geological sequestration at the Ordos CCS Demonstration Project, China and geothermal exploitation at the Geysers geothermal field, California. The results demonstrate that TOUGH2Biot is capable of analyzing change in pressure and temperature, displacement, stress, and potential shear-slip failure caused by large scale underground man-made activity in subsurface flow systems. TOUGH2Biot can also be easily extended for complex coupled process problems in fractured media and be conveniently updated to parallel versions on different platforms to take advantage of high-performance computing.

Impact disruption and recovery of the deep subsurface biosphere

USGS Publications Warehouse

Cockell, Charles S.; Voytek, Mary A.; Gronstal, Aaron L.; Finster, Kai; Kirshtein, Julie D.; Howard, Kieren; Reitner, Joachim; Gohn, Gregory S.; Sanford, Ward E.; Horton, J. Wright; Kallmeyer, Jens; Kelly, Laura; Powars, David S.

2012-01-01

Although a large fraction of the world's biomass resides in the subsurface, there has been no study of the effects of catastrophic disturbance on the deep biosphere and the rate of its subsequent recovery. We carried out an investigation of the microbiology of a 1.76 km drill core obtained from the ~35 million-year-old Chesapeake Bay impact structure, USA, with robust contamination control. Microbial enumerations displayed a logarithmic downward decline, but the different gradient, when compared to previously studied sites, and the scatter of the data are consistent with a microbiota influenced by the geological disturbances caused by the impact. Microbial abundance is low in buried crater-fill, ocean-resurge, and avalanche deposits despite the presence of redox couples for growth. Coupled with the low hydraulic conductivity, the data suggest the microbial community has not yet recovered from the impact ~35 million years ago. Microbial enumerations, molecular analysis of microbial enrichment cultures, and geochemical analysis showed recolonization of a deep region of impact-fractured rock that was heated to above the upper temperature limit for life at the time of impact. These results show how, by fracturing subsurface rocks, impacts can extend the depth of the biosphere. This phenomenon would have provided deep refugia for life on the more heavily bombarded early Earth, and it shows that the deeply fractured regions of impact craters are promising targets to study the past and present habitability of Mars.

Impact disruption and recovery of the deep subsurface biosphere.

PubMed

Cockell, Charles S; Voytek, Mary A; Gronstal, Aaron L; Finster, Kai; Kirshtein, Julie D; Howard, Kieren; Reitner, Joachim; Gohn, Gregory S; Sanford, Ward E; Horton, J Wright; Kallmeyer, Jens; Kelly, Laura; Powars, David S

2012-03-01

Although a large fraction of the world's biomass resides in the subsurface, there has been no study of the effects of catastrophic disturbance on the deep biosphere and the rate of its subsequent recovery. We carried out an investigation of the microbiology of a 1.76 km drill core obtained from the ∼35 million-year-old Chesapeake Bay impact structure, USA, with robust contamination control. Microbial enumerations displayed a logarithmic downward decline, but the different gradient, when compared to previously studied sites, and the scatter of the data are consistent with a microbiota influenced by the geological disturbances caused by the impact. Microbial abundance is low in buried crater-fill, ocean-resurge, and avalanche deposits despite the presence of redox couples for growth. Coupled with the low hydraulic conductivity, the data suggest the microbial community has not yet recovered from the impact ∼35 million years ago. Microbial enumerations, molecular analysis of microbial enrichment cultures, and geochemical analysis showed recolonization of a deep region of impact-fractured rock that was heated to above the upper temperature limit for life at the time of impact. These results show how, by fracturing subsurface rocks, impacts can extend the depth of the biosphere. This phenomenon would have provided deep refugia for life on the more heavily bombarded early Earth, and it shows that the deeply fractured regions of impact craters are promising targets to study the past and present habitability of Mars.

Method for production of hydrocarbons from hydrates

DOEpatents

McGuire, Patrick L.

1984-01-01

A method of recovering natural gas entrapped in frozen subsurface gas hydrate formations in arctic regions. A hot supersaturated solution of CaCl.sub.2 or CaBr.sub.2, or a mixture thereof, is pumped under pressure down a wellbore and into a subsurface hydrate formation so as to hydrostatically fracture the formation. The CaCl.sub.2 /CaBr.sub.2 solution dissolves the solid hydrates and thereby releases the gas entrapped therein. Additionally, the solution contains a polymeric viscosifier, which operates to maintain in suspension finely divided crystalline CaCl.sub.2 /CaBr.sub.2 that precipitates from the supersaturated solution as it is cooled during injection into the formation.

Compositional and Textural Analysis of Maar-Diatreme Volcanic Deposits at Hopi Buttes Volcanic Field (AZ) Using GigaPan Panoramic and Thermal Infrared Imagery

NASA Astrophysics Data System (ADS)

Lee, R.; Graettinger, A. H.; Weinell, M.; Hughes, C. G.

2016-12-01

Basaltic maar-diatreme volcanoes are produced when rising magma interacts with groundwater and produces a maar crater at the ground surface. This crater is underlain by a diatreme, a downward-tapering conical structure filled with a mixture of fragments of intruded magma, fractured host rock, and clasts recycled through repeated discrete subsurface explosions. The debris of the diatreme records the mixing processes caused by subsurface explosions and is the source for ejected material that forms maar tephra rings. Determining the variable depths and lateral locations of these explosions and how energy is dissipated in the subsurface is critical to understanding how maar-diatreme eruptions progress. The Hopi Buttes Volcanic Field (HBVF) in the Navajo Nation, Arizona, USA, contains several diatremes and incised tephra rings with heterolithic clasts 10 mm - 10 m in size, and are well-exposed near-vertical to vertical outcrops. Our ability to measure the length scales and distribution of textures produced by subsurface explosions in these diatremes is limited by the physical accessibility of the exposures, due to both the verticality of the outcrops and the cultural sensitivity of the site. Quantifying the number and locations of explosions is dependent on our ability to investigate the full diatreme outcrop, and not just what can be accessed through traditional field observations. We present a novel field and computer-based technique for both quantitatively and qualitatively characterizing the composition and texture of maar-diatreme deposits in vertical outcrops. This technique uses a combination of field-collected multispectral thermal infrared (TIR) image data and visible wavelength GigaPan imagery to characterize the compositional and textural variations over a whole outcrop. To increase the spatial and spectral resolution of the TIR data, a super-resolution technique will be applied. The technique provides a simple and efficient method to augment the study of the maar-diatreme deposits at HBVF. In addition to contributing to a better understanding of the formation processes of maar-diatreme deposits around the world, the technique also shows great promise for studies involving other types of large outcrops and geologic structures.

Subsurface waste disposal by means of wells - A selective annotated bibliography

USGS Publications Warehouse

Rima, Donald Robert; Chase, Edith B.; Myers, Beverly M.

1971-01-01

Subsurface waste disposal by means of wells is the practice of using drilled wells to inject unwanted substances into underground rock formations. The use of wells for this purpose is not a new idea. As long ago as the end of the last century, it was common practice to drill wells for the express purpose of draining swamps and small lakes to reclaim the land for agricultural purposes. A few decades later in the 1920's and 1930's many oil companies began using injection wells to dispose of oil-field brines and to repressurize oil reservoirs. During World War II, the Atomic Energy Commission began using injection wells to dispose of certain types of radioactive wastes. More recently, injection wells have been drilled to dispose of a variety of byproducts of industrial processes. The number of such wells has increased rapidly since Congress passed the Clean Streams Act of 1966, which restricted the discharge of waste into surface waters.Many scientists and public officials question the propriety of using the term "disposal" when referring to the underground injection of wastes. Their reasons are that underground injection is not, as many advocates claim, "a complete and final answer" to the waste-disposal problem. Rather, it is merely a process wherein the injected wastes are committed to the subsurface with uncertainty as to their ultimate fate or limits of confinement. In effect, the wastes, undiminished and unchanged, are removed from the custody of man and placed in the custody of nature.Although the concept of waste-injection wells is relatively simple, the effects of waste injection can be very complex, particularly when dealing with the exotic and complex components of some industrial wastes. Besides the physical forces of injection, there are many varied interactions between the injected wastes and the materials within the injection zone. Because these changes occur out of sight in the subsurface, they are difficult to assess and not generally understood. In addition, the various aspects of the problem involve a wide spectrum of science and engineering. Hence, articles published on the subject are widely dispersed in the technical and scientific literature. 

Microbiome composition and geochemical characteristics of deep subsurface high-pressure environment, Pyhäsalmi mine Finland

PubMed Central

Miettinen, Hanna; Kietäväinen, Riikka; Sohlberg, Elina; Numminen, Mikko; Ahonen, Lasse; Itävaara, Merja

2015-01-01

Pyhäsalmi mine in central Finland provides an excellent opportunity to study microbial and geochemical processes in a deep subsurface crystalline rock environment through near-vertical drill holes that reach to a depth of more than two kilometers below the surface. However, microbial sampling was challenging in this high-pressure environment. Nucleic acid yields obtained were extremely low when compared to the cell counts detected (1.4 × 104 cells mL−1) in water. The water for nucleic acid analysis went through high decompression (60–130 bar) during sampling, whereas water samples for detection of cell counts by microscopy could be collected with slow decompression. No clear cells could be identified in water that went through high decompression. The high-pressure decompression may have damaged part of the cells and the nucleic acids escaped through the filter. The microbial diversity was analyzed from two drill holes by pyrosequencing amplicons of the bacterial and archaeal 16S rRNA genes and from the fungal ITS regions from both DNA and RNA fractions. The identified prokaryotic diversity was low, dominated by Firmicute, Beta- and Gammaproteobacteria species that are common in deep subsurface environments. The archaeal diversity consisted mainly of Methanobacteriales. Ascomycota dominated the fungal diversity and fungi were discovered to be active and to produce ribosomes in the deep oligotrophic biosphere. The deep fluids from the Pyhäsalmi mine shared several features with other deep Precambrian continental subsurface environments including saline, Ca-dominated water and stable isotope compositions positioning left from the meteoric water line. The dissolved gas phase was dominated by nitrogen but the gas composition clearly differed from that of atmospheric air. Despite carbon-poor conditions indicated by the lack of carbon-rich fracture fillings and only minor amounts of dissolved carbon detected in formation waters, some methane was found in the drill holes. No dramatic differences in gas compositions were observed between different gas sampling methods tested. For simple characterization of gas composition the most convenient way to collect samples is from free flowing fluid. However, compared to a pressurized method a relative decrease in the least soluble gases may appear. PMID:26579109

Detecting and characterizing ice units with the WISDOM Radar

NASA Astrophysics Data System (ADS)

Ciarletti, V.; Plettemeier, D.; Dorizon, S.; Clifford, S. M.; Biancheri-Astier, M.; Dechambre, M.; Saintenoy, A. C.; Costard, F.

2012-12-01

The WISDOM (Water Ice Subsurface Deposit Observation on Mars) Ground Penetrating Radar (GPR) is one of the instruments that have been selected as part of the Pasteur payload of ESA's 2018 ExoMars Rover mission. WISDOM main objectives are to understand the geology and evolution of the landing site and to help identifying locations in the shallow subsurface where organic molecules are the most likely to be found and well-preserved. In the context of the ExoMars mission, the importance of the WISDOM GPR is particularly enhanced by its ability to investigate the distribution and state of subsurface water - both as a liquid and as ice. For example, within the diurnally active thermal layer of the subsurface (i.e., the top ~15 - 25 cm), the transient melting and freezing of subsurface ice and brine may be detectable by comparing day- and night-time radar observations at the same location. Moreover, while the biological significance of liquid water on Mars is obvious, a more readily accessible and enduring record of biological activity may be organic biomarkers preserved in subsurface ice. Unfortunately, the dielectric contrast between rock, soil and ice is small, and therefore, differentiating between mixtures of ice-rich and ice-poor regolith in the Martian subsurface is an extraordinarily difficult task. Preliminary tests in both natural (glacier in the Alps and caves in Austria) and artificial (cold chamber) icy environments have been performed with a prototype representative of the WISDOM instrument flight model. These investigations have demonstrated WISDOM's ability to detect and characterize subsurface ice in various forms. Specific examples will be discussed that demonstrate the instrument's depth of sounding, dielectric sensitivity, spatial resolution, full polarimetric and 3-D capability.

The Chuar Petroleum System, Arizona and Utah

USGS Publications Warehouse

Lillis, Paul G.

2016-01-01

The Neoproterozoic Chuar Group consists of marine mudstone, sandstone and dolomitic strata divided into the Galeros and Kwagunt Formations, and is exposed only in the eastern Grand Canyon, Arizona. Research by the U.S. Geological Survey (USGS) in the late 1980s identified strata within the group to be possible petroleum source rocks, and in particular the Walcott Member of the Kwagunt Formation. Industry interest in a Chuar oil play led to several exploratory wells drilled in the 1990s in southern Utah and northern Arizona to test the overlying Cambrian Tapeats Sandstone reservoir, and confirm the existence of the Chuar in subcrop. USGS geochemical analyses of Tapeats oil shows in two wells have been tentatively correlated to Chuar bitumen extracts. Distribution of the Chuar in the subsurface is poorly constrained with only five well penetrations, but recently published gravity/aeromagnetic interpretations provide further insight into the Chuar subcrop distribution. The Chuar petroleum system was reexamined as part of the USGS Paradox Basin resource assessment in 2011. A map was constructed to delineate the Chuar petroleum system that encompasses the projected Chuar source rock distribution and all oil shows in the Tapeats Sandstone, assuming that the Chuar is the most likely source for such oil shows. Two hypothetical plays were recognized but not assessed: (1) a conventional play with a Chuar source and Tapeats reservoir, and (2) an unconventional play with a Chuar source and reservoir. The conventional play has been discouraging because most surface structures have been tested by drilling with minimal petroleum shows, and there is some evidence that petroleum may have been flushed by CO2 from Tertiary volcanism. The unconventional play is untested and remains promising even though the subcrop distribution of source facies within the Chuar Group is largely unknown.

Design and implementation of a shearing apparatus for the experimental study of shear displacement in rocks

NASA Astrophysics Data System (ADS)

Moore, Johnathan; Crandall, Dustin; Gill, Magdalena; Brown, Sarah; Tennant, Bryan

2018-04-01

Fluid flow in the subsurface is not well understood in the context of "impermeable" geologic media. This is especially true of formations that have undergone significant stress fluctuations due to injection or withdrawal of fluids that alters the localized pressure regime. When the pressure regime is altered, these formations, which are often already fractured, move via shear to reduce the imbalance in the stress state. While this process is known to happen, the evolution of these fractures and their effects on fluid transport are still relatively unknown. Numerous simulation and several experimental studies have been performed that characterize the relationship between shearing and permeability in fractures; while many of these studies utilize measurements of fluid flow or the starting and ending geometries of the fracture to characterize shear, they do not characterize the intermediate stages during shear. We present an experimental apparatus based on slight modifications to a commonly available Hassler core holder that allows for shearing of rocks, while measuring the hydraulic and mechanical changes to geomaterials during intermediate steps. The core holder modification employs the use of semi-circular end caps and structural supports for the confining membrane that allow for free movement of the sheared material while preventing membrane collapse. By integrating this modified core holder with a computed tomography scanner, we show a new methodology for understanding the interdependent behavior between fracture structure and flow properties during intermediate steps in shearing. We include a case study of this device function which is shown here through shearing of a fractured shale core and simultaneous observation of the mechanical changes and evolution of the hydraulic properties during shearing.

Design and implementation of a shearing apparatus for the experimental study of shear displacement in rocks.

PubMed

Moore, Johnathan; Crandall, Dustin; Gill, Magdalena; Brown, Sarah; Tennant, Bryan

2018-04-01

Fluid flow in the subsurface is not well understood in the context of "impermeable" geologic media. This is especially true of formations that have undergone significant stress fluctuations due to injection or withdrawal of fluids that alters the localized pressure regime. When the pressure regime is altered, these formations, which are often already fractured, move via shear to reduce the imbalance in the stress state. While this process is known to happen, the evolution of these fractures and their effects on fluid transport are still relatively unknown. Numerous simulation and several experimental studies have been performed that characterize the relationship between shearing and permeability in fractures; while many of these studies utilize measurements of fluid flow or the starting and ending geometries of the fracture to characterize shear, they do not characterize the intermediate stages during shear. We present an experimental apparatus based on slight modifications to a commonly available Hassler core holder that allows for shearing of rocks, while measuring the hydraulic and mechanical changes to geomaterials during intermediate steps. The core holder modification employs the use of semi-circular end caps and structural supports for the confining membrane that allow for free movement of the sheared material while preventing membrane collapse. By integrating this modified core holder with a computed tomography scanner, we show a new methodology for understanding the interdependent behavior between fracture structure and flow properties during intermediate steps in shearing. We include a case study of this device function which is shown here through shearing of a fractured shale core and simultaneous observation of the mechanical changes and evolution of the hydraulic properties during shearing.

Hydrothermal Alteration Products as Key to Formation of Duricrust and Rock Coatings on Mars

NASA Astrophysics Data System (ADS)

Bishop, J. L.

1999-03-01

A model is presented for the formation of duricrust and rock coatings on Mars. Hydrothermal alteration of volcanic tephra may produce a corrosive agent that attacks rock surfaces and binds dust particles to form duricrust.

Radioactivity and uranium content of the Sharon Springs member of the Pierre shale and associated rocks in western Kansas and eastern Colorado

USGS Publications Warehouse

Landis, Edwin R.

1955-01-01

As a part of the Geological Survey's program of investigating uranium-bearing carbonaceous rocks on behalf of the Division of Raw Materials of the U.S. Atomic Energy Commission, a reconnaissance of the Sharon Springs member of the Pierre shale in western Kansas and eastern Colorado was conducted during 1954. The Sharon Springs member of the Pierre shale and its lateral equivalents ranges from 155 to about 500 feet in thickness and generally contains about 0.001 percent uranium, but some beds contain larger amounts. A 6-foot thick shale bed in Cheyenne County, Colo., contains about 0.006 percent uranium, a 4 1/2-foot thick sequence of beds in Crowley County, Colo., is estimated to contain between 0.004 and 0.005 percent uranium, and a 3 1/2-foot thick sequence of beds in Kiowa County, Colo., contains about 0.004 percent uranium. At several outcrop localities, sequences of beds as much as 9 1/2 feet thick contain about 0.003 percent uranium. Data from wells indicate that the 4 1/2-foot thick sequence of beds in Crowley County, Colo., may have a lateral extent of at least 5 1/2 miles. A gamma-ray log of a well in Yuma County, Colo., indicates the presence of a sequence of beds 66 feet thick which contains 0.005 to 0.010 percent equivalent uranium. No definite pattern of areal distribution of radioactivity and uranium content in the Sharon Springs is indicated by available data. Lateral variation in uranium content of individual beds was not noted in outcrops, which seldom extend more than 150 feet, but subsurface data from gamma-ray logs of wells indicate that both the maximum radioactivity and the thickness of radioactive beds are variable within distances of a few miles. Vertical variation in radioactivity and uranium content of the more radioactive beds is usually abrupt, but in the rocks as a whole the range of uranium content is so small that large variations in content are absent. In most of the gamma-ray logs examined there is only part of the sequence of rocks comprising the Pierre shale and Niobrara formation that exhibits radioactivity in excess of the average radioactivity of the two formations. Comparison of features of gamma-ray logs of wells in north-eastern Colorado suggests that the most radioactive part referred to above is a laterally correlatable sequence of beds. The stratigraphic position of the radioactive unit relative to the Pierre shale-Niobrara formation contact in oil industry scout reports, as identified from electric logs and wells, is variable within short distances. This may indicate that some of the Pierre-Niobrara contacts picked from electric logs may not correspond to the boundary that would be selected by examination of the rocks themselves, or may indicate that there is a facies relationship between teh lowermost part of the Pierre shale and the uppermost part of the Niobrara formation.

Water Pressure Effects on Strength and Deformability of Fractured Rocks Under Low Confining Pressures

NASA Astrophysics Data System (ADS)

Noorian Bidgoli, Majid; Jing, Lanru

2015-05-01

The effect of groundwater on strength and deformation behavior of fractured crystalline rocks is one of the important issues for design, performance and safety assessments of surface and subsurface rock engineering problems. However, practical difficulties make the direct in situ and laboratory measurements of these properties of fractured rocks impossible at present, since effects of complex fracture system hidden inside the rock masses cannot be accurately estimated. Therefore, numerical modeling needs to be applied. The overall objective of this paper is to deepen our understanding on the validity of the effective stress concept, and to evaluate the effects of water pressure on strength and deformation parameters. The approach adopted uses discrete element methods to simulate the coupled stress-deformation-flow processes in a fractured rock mass with model dimensions at a representative elementary volume (REV) size and realistic representation of fracture system geometry. The obtained numerical results demonstrate that water pressure has significant influence on the strength, but with minor effects on elastic deformation parameters, compared with significant influence by the lateral confining pressure. Also, the classical effective stress concept to fractured rock can be quite different with that applied in soil mechanics. Therefore, one should be cautious when applying the classical effective stress concept to fractured rock media.