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1

Controlled CO2 injection into heterogeneous geologic formations for improved solubility and residual trapping  

NASA Astrophysics Data System (ADS)

Geologic CO2 storage (GCS) has been proposed as a potentially viable climate change mitigation option. Among the trapping mechanisms known for permanent CO2 storage in saline aquifers, solubility and residual trapping are important for safe short-term entrapment. These storage mechanisms are hampered by density-driven upward CO2 movement that inhibits the lateral migration of the plume, leaving a large portion of the aquifer volume unexposed to CO2 and unavailable for storage. Heterogeneity of aquifer hydraulic properties and high horizontal/vertical hydraulic conductivity ratio of geologic formations are two competing mechanisms that can hinder upward CO2 migration. Postinjection displacement of free-phase CO2 is somewhat controlled by the heterogeneity in rock permeability and porosity distributions. In particular, low permeability shale layers that act as vertical flow barrier and high-permeability horizontal channels that form flow conduits can spread the CO2 plume laterally in the aquifer. In this paper, we consider CO2 storage in heterogeneous saline aquifers and propose controlled CO2 injection, based on existing knowledge of heterogeneity, to increase CO2 contact with brine and improve the solubility and residual trapping and the overall aquifer storage potential. We examine two optimization methods: directly maximizing the total stored gas in the aquifer, and maximizing the sweep efficiency of the CO2 flood to promote uniform displacement in all directions. We consider the effect of geologic uncertainty on the performance of the controlled injection schemes by using an ensemble of model realizations to represent the uncertainty in aquifer property distribution. We also show how a controlled injection can be used to mitigate the risk of leakage from potential pathways, such as an abandoned well, by restricting CO2 movement toward the leakage zone. Our results suggest that controlled injection can lead to substantial improvements in residual and dissolution trapping and can be used to divert a CO2 plume from approaching sensitive zones or leakage pathways.

Shamshiri, Hossein; Jafarpour, Behnam

2012-02-01

2

Heterogeneity and Scaling in Geologic Media  

SciTech Connect

The accurate characterization and remediation of contaminated subsurface environments requires the detailed knowledge of subsurface structures and flow paths. Enormous resources are invested in scoping and characterizing sites using core sampling, 3-D geophysical surveys, well tests, etc.... Unfortunately, much of the information acquired is lost to compromises and simplifications made in constructing numerical grids for the simulators used to predict flow and transport from the contaminated area to the accessible environment. In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. In the interest of computational efficiency, recognized heterogeneities are simplified, averaged out, or entirely ignored in spite of recent studies that recognize that: (1) Structural and lithologic heterogeneities exist on all scales in rocks. (2) Small heterogeneities influence, and can control the physical and chemical properties of rocks. In this work we propose a physically based approach for the description and treatment of heterogeneities, that highlights the use of laboratory equipment designed to measure the effect on physical properties of fine scale heterogeneities observed in rocks and soils. We then discuss the development of an integration methodology that uses these measurements to develop and upscale flow and transport models. Predictive simulations are 'calibrated' to the measured heterogeneity data, and subsequently upscaled in a way that is consistent with the transport physics and the efficient use of environmental geophysics. This methodology provides a more accurate interpretation and representation of the subsurface for both environmental engineering and remediation. We show through examples, (i) the important influence of even subtle heterogeneity in the interpreting of geophysical data, and (ii) how physically based upscaling can lead to a different and more accurate description of a heterogeneous system, when compared to a more traditional upscaling approach that combines averaging and the application of core-based models. This may be of particular significance in bio-remediation studies where the link between microorganism activity and mesoscale flow through geologic structures, resides in the integration of multiscale processes.

Gregory N. Boitnott; Gilles Y. Bussod; Paul N. Hagin; Stephen R. Brown

2005-04-18

3

Method of fracturing a geological formation  

DOEpatents

An improved method of fracturing a geological formation surrounding a well bore is disclosed. A relatively small explosive charge is emplaced in a well bore and the bore is subsequently hydraulically pressurized to a pressure less than the formation breakdown pressure and preferably greater than the fracture propagation pressure of the formation. The charge is denoted while the bore is so pressurized, resulting in the formation of multiple fractures in the surrounding formation with little or no accompanying formation damage. Subsequent hydraulic pressurization can be used to propagate and extend the fractures in a conventional manner. The method is useful for stimulating production of oil, gas and possibly water from suitable geologic formations.

Johnson, James O. (2679-B Walnut, Los Alamos, NM 87544)

1990-01-01

4

Endogenous Cartel Formation with Heterogeneous Firms  

E-print Network

Endogenous Cartel Formation with Heterogeneous Firms Iwan Bos University of Amsterdam Roetersstraat) joe.harrington@jhu.edu November 12, 2008 JEL Classi...cation: L1, L4 Key Words: Collusion, Cartel Size the composition of a cartel when ...rms are heterogeneous in their ca- pacities. When ...rms are su¢ ciently

Niebur, Ernst

5

Accounting for aquifer heterogeneity from geological data to management tools.  

PubMed

A nested workflow of multiple-point geostatistics (MPG) and sequential Gaussian simulation (SGS) was tested on a study area of 6 km(2) located about 20 km northwest of Quebec City, Canada. In order to assess its geological and hydrogeological parameter heterogeneity and to provide tools to evaluate uncertainties in aquifer management, direct and indirect field measurements are used as inputs in the geostatistical simulations to reproduce large and small-scale heterogeneities. To do so, the lithological information is first associated to equivalent hydrogeological facies (hydrofacies) according to hydraulic properties measured at several wells. Then, heterogeneous hydrofacies (HF) realizations are generated using a prior geological model as training image (TI) with the MPG algorithm. The hydraulic conductivity (K) heterogeneity modeling within each HF is finally computed using SGS algorithm. Different K models are integrated in a finite-element hydrogeological model to calculate multiple transport simulations. Different scenarios exhibit variations in mass transport path and dispersion associated with the large- and small-scale heterogeneity respectively. Three-dimensional maps showing the probability of overpassing different thresholds are presented as examples of management tools. PMID:22924605

Blouin, Martin; Martel, Richard; Gloaguen, Erwan

2013-01-01

6

Petroleum geology of formation waters  

SciTech Connect

Some researchers have argued that most petroleum traps are hydrostatic and the potentiometric surface is a level plane, whereas others have emphasized the importance of hydrodynamic traps and that the potentiometric surface slopes. The Salt Creek oil field, Wyoming is a prime example of the large, anticlinal traps that has produced over 500 million barrels of oil, and was located by a large oil seep over the trap. The structure has five producing zones, all sandstones in the Cretaceous and the Sundance sand (Jurassic). Each has a separate oil-water contact and a transition zone, indicating a lack of permeable interconnection. The multiple oil-water contacts dip northward in pact with the hydraulic gradient of the region. The slope of the potentiometric surface determines whether the water is in a state of static or dynamic equilibrium. A hydrodynamic condition is usually dependent on the topography of the surface and/or the geology of the region. Knowledge of subsurface waters can help in the discovery and seismic mapping of hydrocarbon reservoirs through valuation of possible changes imposed on the waters in the presence of hydrocarbons; by recognition of changes related to conducive development of traps; and eventually by defining condition of origin and migration of oil and gas.

Billo, S.M. [King Saud Univ. (Saudi Arabia)

1996-06-01

7

Study of hydro-geological parameters in a heterogeneous and anisotropic aquifer  

Microsoft Academic Search

Pumping test is the most common way to estimate hydro-geological parameters in the field experiment. The hydro-geological parameters of aquifer in the field are heterogeneous, but many people use the effective parameters which are anisotropic and homogeneous in heterogeneous aquifers to describe the parameters of heterogeneous aquifer. There are a lot of investigations to estimate hydraulic parameters of homogenous aquifer,

Shih-Ching Wu

2010-01-01

8

Simulation of Seismic Tunnel Detection Experiments in Heterogeneous Geological Media  

NASA Astrophysics Data System (ADS)

Detecting covert tunnels and other underground openings is an important yet challenging problem for geophysicists, especially where geological heterogeneity is pronounced. A number of geophysical methods have been employed to solve this problem, each with varying degrees of success. We focus on the near-surface seismic techniques of surface wave backscattering, surface wave attenuation tomography, body wave diffraction imaging, and resonant imaging. We use the elastodynamic wave propagation code E3D to simulate tunnel detection experiments completed at this site for a range of synthetic fractal velocity models. The Black Diamond mine, located near Pittsburg California, is used for the field test of our analysis. Our results show that for the relatively low-frequency surface wave attenuation and backscattering methods, the maximum detectable tunnel depth in a homogenous medium is approximately equal to the wavelength of the probing Rayleigh wave. The higher-frequency body wave diffraction and resonant imaging techniques are able to locate tunnels at greater depths, but require more sophisticated analysis and are prone to greater attenuation losses. As is expected, for large values of heterogeneity amplitude, ?, the percent standard deviation from the mean velocity model, the average observed surface wave attenuation signal decreases and the maximum detectable tunnel depth decreases. However, for moderate values of heterogeneity amplitude (? < 3%), the average surface wave attenuation signal increases and the maximum detectable tunnel depth increases. For the body wave diffraction and resonant imaging experiments, as ? increases the complexity of the observed signal increases, resulting in more difficult processing and interpretation. The additional scattering attenuation tends to degrade the signals significantly due to their reliance on lower amplitude and higher frequency waves.

Sherman, C. S.; Glaser, S. D.; Rector, J.

2013-12-01

9

Continuum-scale convective mixing in geological CO2 sequestration in anisotropic and heterogeneous saline aquifers  

NASA Astrophysics Data System (ADS)

Deep saline aquifers are important geological formations for CO2 sequestration. It has been known that dissolution of CO2 increases brine density, which results in downward density-driven convection and consequently greatly enhances CO2 sequestration. In this study, a continuum-scale lattice Boltzmann model is used to investigate convective mixing of CO2 in saline aquifers. It is found that increasing permeability in either the vertical or horizontal direction accelerates the development of convective mixing. In a heterogeneous aquifer, increasing heterogeneity hampers the onset of convective mixing, because the heterogeneous permeability field results in a large portion of low-velocity region which reduces the instability of the system. The critical time for the onset of instability depends mainly on the coefficient of variation (COV) of the permeability field, and is insensitive to the correlation length. This implies that within the scale of critical time, mass transport is dominated by diffusion, and thus depends mainly on fine-scale heterogeneity controlled by COV. We derived an empirical formula for estimating the critical time, which leads to good estimates for all combinations of COV and correlation length. Fingering, channeling, and dispersion are the three mechanisms for mass transport. In dispersion, dissolved mass is approximately proportional to the square root of time, while in fingering and channeling it is approximately proportional to time. Mass transport by channeling depends significantly on permeability structure, while by fingering it is controlled by gravitational instability. It is also found that larger volumes of CO2 can be stored in heterogeneous aquifers because of higher mass dissolution rates.

Chen, Cheng; Zeng, Lingzao; Shi, Liangsheng

2013-03-01

10

Geologic Study of the Coso Formation  

SciTech Connect

There have been great advances in the last 20 years in understanding the volcanic, structural, geophysical, and petrologic development of the Coso Range and Coso geothermal field. These studies have provided a wealth of knowledge concerning the geology of the area, including general structural characteristics and kinematic history. One element missing from this dataset was an understanding of the sedimentology and stratigraphy of well-exposed Cenozoic sedimentary strata - the Coso Formation. A detailed sedimentation and tectonics study of the Coso Formation was undertaken to provide a more complete picture of the development of the Basin and Range province in this area. Detailed mapping and depositional analysis distinguishes separate northern and southern depocenters, each with its own accommodation and depositional history. While strata in both depocenters is disrupted by faults, these faults show modest displacement, and the intensity and magnitude of faulting does no t record significant extension. For this reason, the extension between the Sierran and Coso blocks is interpreted as minor in comparison to range bounding faults in adjacent areas of the Basin and Range.

D. L. Kamola; J. D. Walker

1999-12-01

11

Constructing Hydraulic Barriers in Deep Geologic Formations  

SciTech Connect

Many construction methods have been developed to create hydraulic barriers to depths of 30 to 50 meters, but few have been proposed for depths on the order of 500 meters. For these deep hydraulic barriers, most methods are potentially feasible for soil but not for hard rock. In the course of researching methods of isolating large subterranean blocks of oil shale, the authors have developed a wax thermal permeation method for constructing hydraulic barriers in rock to depths of over 500 meters in competent or even fractured rock as well as soil. The technology is similar to freeze wall methods, but produces a permanent barrier; and is potentially applicable in both dry and water saturated formations. Like freeze wall barriers, the wax thermal permeation method utilizes a large number of vertical or horizontal boreholes around the perimeter to be contained. However, instead of cooling the boreholes, they are heated. After heating these boreholes, a specially formulated molten wax based grout is pumped into the boreholes where it seals fractures and also permeates radially outward to form a series of columns of wax-impregnated rock. Rows of overlapping columns can then form a durable hydraulic barrier. These barriers can also be angled above a geologic repository to help prevent influx of water due to atypical rainfall events. Applications of the technique to constructing containment structures around existing shallow waste burial sites and water shutoff for mining are also described. (authors)

Carter, E.E.; Carter, P.E. [Technologies Co, Texas (United States); Cooper, D.C. [Ph.D. Idaho National Laboratory, Idaho Falls, ID (United States)

2008-07-01

12

Anomalous diffusion of electromagnetic eddy currents in geological formations  

NASA Astrophysics Data System (ADS)

Controlled-source electromagnetic (EM) induction in some geological formations is shown here to be compactly described by an anomalous subdiffusion process. Such a process, which is not universal, is governed by a fractional diffusion equation or alternatively the convolutional form of Ohm's law. A subdiffusing eddy current vortex, or electromagnetic smoke ring, propagates in such a way that its position of median intensity overruns its position of peak intensity. This behavior is not allowed in classical diffusion but is a simple consequence of diffusion within a stationary fractal medium. A similar analysis has been applied to understand heavy-tailed traveltime distributions that appear in certain hydrological time series. The tell-tale signature of anomalous electromagnetic diffusion is a slope ? of the magnetic zero-crossing moveout curve that is constant with transmitter-receiver (RX) offset and significantly different from unity. Neither lateral heterogeneity nor unixial anisotropy can generate such a constant-slope moveout curve with an economy of model parameters. Controlled-source EM data from two sites in Texas and one in New Mexico are used in this study to test the eddy current subdiffusion hypothesis.

Weiss, Chester J.; Everett, Mark E.

2007-08-01

13

Geology, Formation and Fossils of the Connecticut Valley  

Microsoft Academic Search

Fossils and fossil footprints allow geologists to learn not only of the geological formation of a certain region, but also of the biodiversity of plant and animal life. The abundant fossil footprints of Connecticut Valley allow us to glimpse at life about two hundred million years ago. Connecticut, during this time period, was characterized by the lush tropical forests as

Naila Eisa; Lorenzo Bellard

14

Transient well-type flows in heterogenous formations  

Microsoft Academic Search

The problem of averaging transient flows by sources of a given head boundary condition in heterogeneous formations of random conductivity is investigated. The study generalizes the recently developed mathematical model of average transient nonuniform flow [Indelman, 1996; Tartakovsky and Neuman, 1998a]. The latter allows calculating the mean head for sources of flux boundary condition and, as such, is not applicable

Peter Indelman

2003-01-01

15

Process for stabilizing rock and coal formations by bonding these formations to themselves or other geological formations  

Microsoft Academic Search

The invention relates to a process for stabilizing rock and coal formations by bonding them to each other or to other geological formations. The bonding material is a reactive organic polyisocyanate-polyol mixture which may contain a catalyst.

D. Arndt; D. Hobein

1984-01-01

16

Applying Seismic Methods to National Security Problems: Matched Field Processing With Geological Heterogeneity  

SciTech Connect

Seismic imaging and tracking methods have intelligence and monitoring applications. Current systems, however, do not adequately calibrate or model the unknown geological heterogeneity. Current systems are also not designed for rapid data acquisition and analysis in the field. This project seeks to build the core technological capabilities coupled with innovative deployment, processing, and analysis methodologies to allow seismic methods to be effectively utilized in the applications of seismic imaging and vehicle tracking where rapid (minutes to hours) and real-time analysis is required. The goal of this project is to build capabilities in acquisition system design, utilization of full three-dimensional (3D) finite difference modeling, as well as statistical characterization of geological heterogeneity. Such capabilities coupled with a rapid field analysis methodology based on matched field processing are applied to problems associated with surveillance, battlefield management, finding hard and deeply buried targets, and portal monitoring. This project, in support of LLNL's national-security mission, benefits the U.S. military and intelligence community. Fiscal year (FY) 2003 was the final year of this project. In the 2.5 years this project has been active, numerous and varied developments and milestones have been accomplished. A wireless communication module for seismic data was developed to facilitate rapid seismic data acquisition and analysis. The E3D code was enhanced to include topographic effects. Codes were developed to implement the Karhunen-Loeve (K-L) statistical methodology for generating geological heterogeneity that can be utilized in E3D modeling. The matched field processing methodology applied to vehicle tracking and based on a field calibration to characterize geological heterogeneity was tested and successfully demonstrated in a tank tracking experiment at the Nevada Test Site. A three-seismic-array vehicle tracking testbed was installed on site at LLNL for testing real-time seismic tracking methods. A field experiment was conducted over a tunnel at the Nevada Site that quantified the tunnel reflection signal and, coupled with modeling, identified key needs and requirements in experimental layout of sensors. A large field experiment was conducted at the Lake Lynn Laboratory, a mine safety research facility in Pennsylvania, over a tunnel complex in realistic, difficult conditions. This experiment gathered the necessary data for a full 3D attempt to apply the methodology. The experiment also collected data to analyze the capabilities to detect and locate in-tunnel explosions for mine safety and other applications. In FY03 specifically, a large and complex simulation experiment was conducted that tested the full modeling-based approach to geological characterization using E2D, the K-L statistical methodology, and matched field processing applied to tunnel detection with surface seismic sensors. The simulation validated the full methodology and the need for geological heterogeneity to be accounted for in the overall approach. The Lake Lynn site area was geologically modeled using the code Earthvision to produce a 32 million node 3D model grid for E3D. Model linking issues were resolved and a number of full 3D model runs were accomplished using shot locations that matched the data. E3D-generated wavefield movies showed the reflection signal would be too small to be observed in the data due to trapped and attenuated energy in the weathered layer. An analysis of the few sensors coupled to bedrock did not improve the reflection signal strength sufficiently because the shots, though buried, were within the surface layer and hence attenuated. Ability to model a complex 3D geological structure and calculate synthetic seismograms that are in good agreement with actual data (especially for surface waves and below the complex weathered layer) was demonstrated. We conclude that E3D is a powerful tool for assessing the conditions under which a tunnel could be detected in a specific geological setting. Finally, the Lak

Myers, S; Larsen, S; Wagoner, J; Henderer, B; McCallen, D; Trebes, J; Harben, P; Harris, D

2003-10-29

17

Integration of Seismic and SkyTEM in a Heterogeneous Geological Setting  

NASA Astrophysics Data System (ADS)

The topic of this presentation is to show the benefits of integrating seismic and SkyTEM data acquired in an area with a highly heterogeneous geological setting. The study area is situated close to the town of Oelgod in western Denmark and covers 14 square kilometres. In this area SkyTEM lines with a spacing of approximately 100 meters have been measured, and in addition to this 80 kilometres seismic profiling has been acquired in and in the vicinity of the study area. This dense data coverage of a geologically complex area is unique, and provides an optimal basis for assessment of the benefits from integrating the two methods. The SkyTEM method is currently the most widely used geophysical method for groundwater mapping in Denmark. SkyTEM is an airborne transient electromagnetic method with which data are collected continuously along parallel lines. The method is especially good at mapping the distribution of conductive layers at depths to about 250 meters. By undertaking airborne SkyTEM surveys it is possible to collect dense data grids over large survey areas. Such data sets often form the basis for three-dimensional geological interpretations. In order to obtain a larger degree of detail and thereby improved reliability of geological interpretations we find it advantageous to combine SkyTEM results with high-resolution seismic profiling. Seismic profiles may contribute with important information on the specific structural setting. The SkyTEM data show a highly complex setting with ridges, valleys, depressions and hummocks. These structures are found at depths down to about 200 meters. The structures are laterally well resolved due to the close line spacing. Resistivity levels and lithological information available from few, scattered groundwater wells suggest clay-sand lithologies. Detailed characterisation of the structural features in the sediments are not revealed in the SkyTEM data, but can be provided by the seismic data. Thus, combined application of the two methods will allow for construction of more exact geological models. High-resolution seismic surveying offers useful and detailed information along 2D sections, but as compared to the SkyTEM method it is expensive in use and difficult to carry out in areas of limited access. In order to resolve heterogeneous geology, dense areal data coverage is needed in combination with detailed insight in geological key features. The first demand is met by the SkyTEM method, and the second by the seismic method. An investigation strategy starting with SkyTEM, and followed by seismics along profiles located on lines selected from SkyTEM interpretations, therefore, provides a strong cost-effective approach when dealing with complex geology.

Christensen, A. H.; Lykke-Andersen, H.; Jorgensen, F.; Nørmark, E.; Auken, E.

2009-12-01

18

Geological pattern formation by growth and dissolution in aqueous systems  

SciTech Connect

Although many geological processes take place on time scales that are very long compared with the human experience, essentially all geological processes, fast or slow, are far from equilibrium processes. Surprisingly often, geological processes lead to the formation of quite simple and distinctive patterns, which hint at an underlying simplicity in many complex geological systems.. The ability to predict the seasons was critically important to early human society, and Halley’s prediction of the return of the comet that bears his name is still considered to be a scientific milestone. Spatial patterns have also attracted attention because of their aesthetic appeal, which depends in subtle ways on a combination of regularity and irregularity. In recent decades, rapid growth in the capabilities of digital computers has facilitated the simulation of pattern formation processes, and computer simulations have become an important tool for evaluating theoretical concepts and for scientific discovery. Computer technology in combination with other technologies such as high resolution digital cameras, scanning microprobes (atomic force microscopy AFM), confocal microscopy, and scanning tunneling microscopy (STM), for example) has facilitated the quantitative characterization of patterns over a wide range of scales and has enabled rapid advances in our ability to understand the links between large scale pattern formation and microscopic processes. The ability to quantitatively characterize patterns is important because it enables a more rigorous comparison between the predictions of computer models and real world patterns and their formation.In some cases, the idea that patterns with a high degree of regularity have simple origins appears to be justified, but in other cases, such as the formation of almost perfectly circular stone rings due to freeze-thaw cycles simple patterns appear to be the consequence of quite complex processes. In other cases, it has been shown that very simple non-linear processes can lead to extremely complicated patterns, and that some apparently complex disordered systems can be described quantitatively in terms of simple fractal models.

Paul Meakin

2010-03-01

19

Cirrus cloud formation and the role of heterogeneous ice nuclei  

NASA Astrophysics Data System (ADS)

Composition, size, and phase are key properties that define the ability of an aerosol particle to initiate ice in cirrus clouds. Properties of cirrus ice nuclei (IN) have not been well constrained due to a lack of systematic measurements in the upper troposphere. We have analyzed the size and composition of sublimated cirrus particles sampled from a high altitude research aircraft using both in situ and offline techniques. Mineral dust and metallic particles are the most enhanced residue types relative to background aerosol. Using a combination of cirrus residue composition, relative humidity, and cirrus particle concentration measurements, we infer that heterogeneous nucleation is a dominant cirrus formation mechanism for the mid-latitude, subtropical, and tropical regions under study. Other proposed heterogeneous IN including biomass burning particles, elemental carbon, and biological material were not abundant in cirrus residuals.

Froyd, Karl D.; Cziczo, Daniel J.; Hoose, Corinna; Jensen, Eric J.; Diao, Minghui; Zondlo, Mark A.; Smith, Jessica B.; Twohy, Cynthia H.; Murphy, Daniel M.

2013-05-01

20

Background seismicity controlled by heterogeneity in subsurface geology: An example from the Wakayama region, southwest Japan  

NASA Astrophysics Data System (ADS)

Heterogeneity associated with shallow geologic structure is one of the factors to control the earthquake occurrence in the crust. Material properties properties such as strength, permeability, fluid content, and rheology, reflected from different lithological units may influence faulting behavior, thus seismicity. To explore the role of geologic heterogeneity into the seismicity, here we examine the spatial relationship between seismicity and geologic structure in the Wakayama region, northwestern Kii Peninsula, in which a significant high background rate of seismicity has been continuously recorded since the mid-1900 (~100 M?2.0 earthquakes recorded per year since 2000). Epicenters of numerous small earthquakes are located mainly on the Mesozoic metamorphic rocks and accretion units bounded by major tectonic lines, which dimension is roughly ~40 km x ~40 km (hereinafter 'Wakayama seismic zone'). Within the Wakayama seismic zone, we observe many E-W and ENE-WSW trending dense seismic clusters plotted by the Japan Meteorological Agency (JMA) catalog. To see finer internal hypocenter distribution particularly characteristics of the seismic clusters, we employed the hypoDD method (Waldhauser and Ellsworth, 2000) to relocate the JMA hypocenters. Our hypoDD catalog made the clouds of clusters much sharper and enables us to compare with the detail and local geologic structure. We found that most of the E-W trending seismic clusters possibly correspond to the E-W trending local scale geologic faults, folds, bedding planes, and schistosity. We also found that there are two ~15-km-long and ~5-km-wide aseismic zones that are well corresponding to mafic to ultramafic rocks including serpentine (called 'Mikabu zone'). The Mikabu zones are also well expressed by the high Bouguer anomalies (Geological Survey of Japan, 2013). Employing Talwani model (Talwani, 1959), we estimated that higher density ultra-mafic rocks extended up to 5 km deep from the surface. We interpret that either high shear modulus (stronger) or less ductile property of ultra-mafic rocks dominate aseismic behavior. Unlike such significant E-W striking features, however, well-determined fault plane solutions by JMA and the National Research Institute for Earth Science and Disaster Prevention (NIED) show NS-trending reverse faults corresponding to EW compression. To resolve the inconsistency between the seismic trend and dominant fault strike, we further sought the focal mechanisms for smaller earthquakes using waveform data (P-wave first motion polarites) recorded in the SATARN seismic network system of DPRI, Kyoto University. As a result, among the many reverse fault mechanisms, we found some amounts of strike-slip ones, which may associate with the visible EW-trending seismic clusters. A few normal faulting solutions also suggest that local heterogeneity in stress and strength along the N-E trending geologic features originated from subduction accretional tectonics.

Maeda, S.; Toda, S.; Katao, H.

2013-12-01

21

Role of particulate metals in heterogenous secondary sulfate formation  

NASA Astrophysics Data System (ADS)

A series of field sampling and controlled laboratory experiments were undertaken to quantify the role of trace metals found in ambient fine particulate matter and metal-rich primary sources in the heterogenous catalytic conversion of SO2 gas into sulfate particulate matter (PM) in the atmosphere. Analysis produced source profiles of three primary source materials, fluidized-bed catalytic cracking catalyst, coal-fired combustion fly ash, and paved road dust, featuring 33 elements including rare earth metals, which are not commonly reported in the literature. Subsequently three sets of experiments were conducted exposing 1) source materials, 2) ambient PM, and 3) ambient PM augmented with approximately an equal amount of source material to SO2 gas and measuring sulfate formation. Source material experiments revealed that the greatest extent of reaction was on the surface of coal fly ash with sulfate formation of 19 ± 5 mg sulfate g-1 material. Ambient fine particulate matter (PM) experiments showed sulfate formation ranging from negligible amounts to 180 ± 10 mg sulfate g-1 PM. It was much more difficult to quantify the sulfate formation on ambient filters augmented with the source materials. In these experiments, sulfate formation ranged from negligible amounts to 40 ± 8 mg sulfate g-1 of particles (ambient + augmented material). These three sets of experiments shows that heterogenous sulfate formation is often negligible but, under some conditions can contribute 10% or more to the total sulfate concentrations when exposed to high SO2 concentrations such as those found in plumes. Factor analysis of the source material experiments grouped metals into two categories, crustal components and anthropogenically emitted metals representative of catalyst material, with the former showing the strongest correlation with sulfate formation. Subsequent analysis of data collected from the ambient PM experiments showed a much weaker correlation of sulfate formation with the crustal components, including iron and titanium, remaining clustered with sulfate formation. Independent research has been previously reported in the literature establishing mechanisms for the iron and titanium catalyzed conversion of S(IV) to S(VI) suggesting there may be other metals within these crustal type metal components that behave similarly. Additional experiments spanning a wider range of variables including more sources, SO2 concentrations and exposure times, ambient PM locations, as well as more individual samples may be necessary to obtain more conclusive evidence into the role of various metals in catalyzing the conversion of S(IV) to S(VI).

Clements, Andrea L.; Buzcu-Guven, Birnur; Fraser, Matthew P.; Kulkarni, Pranav; Chellam, Shankararaman

2013-08-01

22

Estimation of hydrologic properties of heterogeneous geologic media with an inverse method based on iterated function systems  

SciTech Connect

The hydrologic properties of heterogeneous geologic media are estimated by simultaneously inverting multiple observations from well-test data. A set of pressure transients observed during one or more interference tests is compared to the corresponding values obtained by numerically simulating the tests using a mathematical model. The parameters of the mathematical model are varied and the simulation repeated until a satisfactory match to the observed pressure transients is obtained, at which point the model parameters are accepted as providing a possible representation of the hydrologic property distribution. Restricting the search to parameters that represent fractal hydrologic property distributions can improve the inversion process. Far fewer parameters are needed to describe heterogeneity with a fractal geometry, improving the efficiency and robustness of the inversion. Additionally, each parameter set produces a hydrologic property distribution with a hierarchical structure, which mimics the multiple scales of heterogeneity often seen in natural geological media. Application of the IFS inverse method to synthetic interference-test data shows that the method reproduces the synthetic heterogeneity successfully for idealized heterogeneities, for geologically-realistic heterogeneities, and when the pressure data includes noise.

Doughty, C.A.

1996-05-01

23

Modeling fine-scale geological heterogeneity--examples of sand lenses in tills.  

PubMed

Sand lenses at various spatial scales are recognized to add heterogeneity to glacial sediments. They have high hydraulic conductivities relative to the surrounding till matrix and may affect the advective transport of water and contaminants in clayey till settings. Sand lenses were investigated on till outcrops producing binary images of geological cross-sections capturing the size, shape and distribution of individual features. Sand lenses occur as elongated, anisotropic geobodies that vary in size and extent. Besides, sand lenses show strong non-stationary patterns on section images that hamper subsequent simulation. Transition probability (TP) and multiple-point statistics (MPS) were employed to simulate sand lens heterogeneity. We used one cross-section to parameterize the spatial correlation and a second, parallel section as a reference: it allowed testing the quality of the simulations as a function of the amount of conditioning data under realistic conditions. The performance of the simulations was evaluated on the faithful reproduction of the specific geological structure caused by sand lenses. Multiple-point statistics offer a better reproduction of sand lens geometry. However, two-dimensional training images acquired by outcrop mapping are of limited use to generate three-dimensional realizations with MPS. One can use a technique that consists in splitting the 3D domain into a set of slices in various directions that are sequentially simulated and reassembled into a 3D block. The identification of flow paths through a network of elongated sand lenses and the impact on the equivalent permeability in tills are essential to perform solute transport modeling in the low-permeability sediments. PMID:23252428

Kessler, Timo Christian; Comunian, Alessandro; Oriani, Fabio; Renard, Philippe; Nilsson, Bertel; Klint, Knud Erik; Bjerg, Poul Løgstrup

2013-01-01

24

COMMENT ON 'AN ADVECTION-DIFFUSION CONCEPT FOR SOLUTE TRANSPORT IN HETEROGENEOUS UNCONSOLIDATED GEOLOGICAL DEPOSITS' BY GILLHAM ET AL  

EPA Science Inventory

The article is a technical commentary relating to the article, 'An Advection-Diffusion Concept for Solute Transport in Heterogenous Unconsolidated Geological Deposits,' by Gillham, et al, Water Resources Research 20(3):369-378, 1984. The authors principal comments relate to the c...

25

Application of multiple-point geostatistics on modelling pumping tests and tracer tests in heterogeneous environments with complex geological structures  

NASA Astrophysics Data System (ADS)

In heterogeneous environments with complex geological structures, analysis of pumping and tracer tests is often problematic. Standard interpretation methods do not account for heterogeneity or simulate this heterogeneity introducing empirical zonation of the calibrated parameters or using variogram-based geostatistical techniques that are often not able to describe realistic heterogeneity in complex geological environments where e.g. sedimentary structures, multi-facies deposits, structures with large connectivity or curvi-linear structures can be present. Multiple-point geostatistics aims to overcome the limitations of the variogram and can be applied in different research domains to simulate heterogeneity in complex environments. In this project, multiple-point geostatistics is applied to the interpretation of pumping tests and a tracer test in an actual case of a sandy heterogeneous aquifer. This study allows to deduce the main advantages and disadvantages of this technique compared to variogram-based techniques for interpretation of pumping tests and tracer tests. A pumping test and a tracer test were performed in the same sandbar deposit consisting of cross-bedded units composed of materials with different grain sizes and hydraulic conductivities. The pumping test and the tracer test are analyzed with a local 3D groundwater model in which fine-scale sedimentary heterogeneity is modelled using multiple-point geostatistics. To reduce CPU and RAM requirements of the multiple-point geostatistical simulation steps, edge properties indicating the presence of irregularly-shaped surfaces are directly simulated. Results show that for the pumping test as well as for the tracer test, incorporating heterogeneity results in a better fit between observed and calculated drawdowns/concentrations. The improvement of the fit is however not as large as expected. In this paper, the reasons for these somewhat unsatisfactory results are explored and recommendations for future applications of multiple-point geostatistics on pumping tests and tracer tests are formulated.

Huysmans, Marijke; Dassargues, Alain

2014-05-01

26

A Formative Assessment of Geologic Time for High School Earth Science Students  

NSDL National Science Digital Library

Earth science courses typically include the concept of geological time. The authors of this study attempt to move past traditional assessment practices and develop a formative assessment of students' understanding of the construction of the geologic time scale and how it is interpreted. Through this approach students are challenged to conceptualize the geologic time scale by comparing it to a student-produced time scale for an older adult's life. This formative assessment allows the teacher to alter instruction based on students' feedback in order to maximize student understanding of geologic time.

2004-05-01

27

Statistical characterisation and stochastic parameterisation of sedimentary geological formations on their reaction capacity for sustainable groundwater quality management  

NASA Astrophysics Data System (ADS)

The fate of contaminants in groundwater aquifers is determined by the buffering capacity of those aquifers together with the composition of inflowing groundwater. A nationwide characterisation of the environmental geochemistry of the shallow subsurface (down to 30 m below surface) has been started in the Netherlands. This covers: 1. the reaction capacity of sediments as buffer for contamination, and 2. typical elemental composition of geological formations and the association between trace elements and major minerals. For this purpose, the Netherlands is subdivided into 27 so-called geotop regions each having a unique geological build-up of the shallow subsurface. Here, four types are recognised based on vertical hydrogeological build-up. The regions are statistically characterised on their geochemical composition using combinations of lithological class and geological formation as strata. The statistical data are subsequently coupled with a geological voxel model of the subsurface to stochastically parameterise the geological units on reaction capacity. This combined approach will be illustrated for the Dutch province Zeeland. Reaction capacity is considered as a series of geochemical characteristics that control acid/base condition, redox condition and sorption capacity. Five primary reaction capacity variables are characterised: 1. pyrite, 2. non-pyrite, reactive iron (oxides, siderite and glauconite), 3. clay fraction, 4. organic matter and 5. Ca-carbonate. Important reaction capacity variables that are determined by more than one solid compound are also deduced: 1. potential reduction capacity (PRC) by pyrite and organic matter, 2. cation-exchange capacity (CEC) by organic matter and clay content, 3. carbonate buffering upon pyrite oxidation (CPBO) by carbonate and pyrite. A statistical investigation of several hunderds of sediment analyses is performed that provides the geochemical properties of the sediments. Here, classification based on sedimentary facies may provide additional insight on spatial heterogeneity within lithological classes. A two-step stochastic algoritm is established for parameterisation of a geological voxel model. First, the cumulative frequency distribution (cfd) functions are calculated for the geochemical strata. Next, all voxels are classified into the geochemical strata and the cfd functions are used to put random reaction capacity variables into the geological voxel model. The result is a heterogeneous geochemical reaction capacity model of the subsurface having grid cells of 100x100x0.5 m. This model can be used in e.g. groundwater transport models or other instruments for groundwater quality management.

Griffioen, J.; Vermooten, S.; Keijzer, T.; Bakr, M.; Valstar, J.

2012-04-01

28

Approaches to identifying reservoir heterogeneity and reserve growth opportunities from subsurface data: The Oficina Formation, Budare field, Venezuela  

SciTech Connect

We applied an integrated geologic, geophysical, and engineering approach devised to identify heterogeneities in the subsurface that might lead to reserve growth opportunities in our analysis of the Oficina Formation at Budare field, Venezuela. The approach involves 4 key steps: (1) Determine geologic reservoir architecture; (2) Investigate trends in reservoir fluid flow; (3) Integrate fluid flow trends with reservoir architecture; and (4) Estimate original oil-in-place, residual oil saturation, and remaining mobile oil, to identify opportunities for reserve growth. There are three main oil-producing reservoirs in the Oficina Formation that were deposited in a bed-load fluvial system, an incised valley-fill, and a barrier-strandplain system. Reservoir continuity is complex because, in addition to lateral facies variability, the major Oficina depositional systems were internally subdivided by high-frequency stratigraphic surfaces. These surfaces define times of intermittent lacustrine and marine flooding events that punctuated the fluvial and marginal marine sedimentation, respectively. Syn and post depositional faulting further disrupted reservoir continuity. Trends in fluid flow established from initial fluid levels, response to recompletion workovers, and pressure depletion data demonstrated barriers to lateral and vertical fluid flow caused by a combination of reservoir facies pinchout, flooding shale markers, and the faults. Considerable reserve growth potential exists at Budare field because the reservoir units are highly compartment by the depositional heterogeneity and structural complexity. Numerous reserve growth opportunities were identified in attics updip of existing production, in untapped or incompletely drained compartments, and in field extensions.

Hamilton, D.S.; Raeuchle, S.K.; Holtz, M.H. [Bureau of Economic Geology, Austin, TX (United States)] [and others

1997-08-01

29

The geologic mapping of Venus using C-1 format: Sheets 75N254, 60N263  

NASA Technical Reports Server (NTRS)

The results of geologic mapping of Venus, produced on the base of Magellan images, are presented. We submit two C-1 format geologic maps with the appropriate legend. The mapping territory was taken from Venera 15 and 16 missions and geologic maps were composed. Magellan images allow us to divide some types of the plains units to determine the lava flow direction and to map with better accuracy.

Shalimov, I. V.

1992-01-01

30

Estimation of hydrologic properties of heterogeneous geologic media with an inverse method based on iterated function systems  

SciTech Connect

The highly heterogeneous nature of most geologic media, coupled with the restricted view of the subsurface available through boreholes, makes it difficult to determine the spatial distribution of subsurface hydrologic properties. Without such a description one cannot predict how fluid flow or solute transport will occur through permeable geologic media, and these predictions are critically needed to address many important environmental problems, including toxic chemical spills, leaking underground storage tanks, and long-term radioactive waste isolation. A common concern of these problems is the possible existence of high-permeability pathways connecting the problem to the biosphere. An understanding of flow and transport behavior is also necessary to optimize energy extraction from petroleum or geothermal reservoirs, where identifying low-permeability barriers that compartmentalize reservoirs and hamper efficient resource utilization is a key problem. The present work describes the development and application of a new inverse method for determining the spatial distribution of hydrologic properties (permeability and specific storage) in heterogeneous geologic media, using pressure transients from interference well tests. The method employs fractal concepts to improve efficiency and reliability. It is applicable to any sort of heterogeneous geologic medium in which wells communicate with each other, whether it be porous, fractured, or a combination thereof. Application to field data from a shallow aquifer at Kesterson Reservoir agrees well with an independent analysis using traditional well-test analysis methods. Application to a series of interference tests conducted at the Gypsy Pilot Site produces a detailed picture of the subsurface, which compares favorably with cross-well seismic imaging studies. 53 refs.

Doughty, C. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley Lab., CA (United States). Earth Sciences Div.

1995-12-01

31

Nitrate reduction in geologically heterogeneous catchments--a framework for assessing the scale of predictive capability of hydrological models.  

PubMed

In order to fulfil the requirements of the EU Water Framework Directive nitrate load from agricultural areas to surface water in Denmark needs to be reduced by about 40%. The regulations imposed until now have been uniform, i.e. the same restrictions for all areas independent of the subsurface conditions. Studies have shown that on a national basis about 2/3 of the nitrate leaching from the root zone is reduced naturally, through denitrification, in the subsurface before reaching the streams. Therefore, it is more cost-effective to identify robust areas, where nitrate leaching through the root zone is reduced in the saturated zone before reaching the streams, and vulnerable areas, where no subsurface reduction takes place, and then only impose regulations/restrictions on the vulnerable areas. Distributed hydrological models can make predictions at grid scale, i.e. at much smaller scale than the entire catchment. However, as distributed models often do not include local scale hydrogeological heterogeneities, they are typically not able to make accurate predictions at scales smaller than they are calibrated. We present a framework for assessing nitrate reduction in the subsurface and for assessing at which spatial scales modelling tools have predictive capabilities. A new instrument has been developed for airborne geophysical measurements, Mini-SkyTEM, dedicated to identifying geological structures and heterogeneities with horizontal and lateral resolutions of 30-50 m and 2m, respectively, in the upper 30 m. The geological heterogeneity and uncertainty are further analysed by use of the geostatistical software TProGS by generating stochastic geological realisations that are soft conditioned against the geophysical data. Finally, the flow paths within the catchment are simulated by use of the MIKE SHE hydrological modelling system for each of the geological models generated by TProGS and the prediction uncertainty is characterised by the variance between the predictions of the different models. PMID:23953482

Refsgaard, Jens Christian; Auken, Esben; Bamberg, Charlotte A; Christensen, Britt S B; Clausen, Thomas; Dalgaard, Esben; Effersø, Flemming; Ernstsen, Vibeke; Gertz, Flemming; Hansen, Anne Lausten; He, Xin; Jacobsen, Brian H; Jensen, Karsten Høgh; Jørgensen, Flemming; Jørgensen, Lisbeth Flindt; Koch, Julian; Nilsson, Bertel; Petersen, Christian; De Schepper, Guillaume; Schamper, Cyril; Sørensen, Kurt I; Therrien, Rene; Thirup, Christian; Viezzoli, Andrea

2014-01-15

32

Evaluating variable switching and flash methods in modeling carbon sequestration in deep geologic formations  

E-print Network

Evaluating variable switching and flash methods in modeling carbon sequestration in deep geologic performance computing to assess the risks involved in carbon sequestration in deep geologic formations-thermal- chemical processes in variably saturated, non-isothermal porous media is applied to sequestration

Mills, Richard

33

Study of effects of formation heterogeneity of carbon dioxide gas migration using a two-dimensional intermediate scale  

NASA Astrophysics Data System (ADS)

An important issue that needs attention in designing effective storage schemes for storage of CO2 in deep geologic formations is the assessment of risk of potential leakage. Leaking gas threatening the surface and groundwater sources and vegetation. In our research group, we have conducted experiments in soil columns to obtain a fundamental understanding of formation of gas and its migration. The results of these experiments demonstrated that a number of factors that include pressure gradients, temperature and formation heterogeneity, among others controls these processes. As a first step to upscale these findings from one-dimensional columns to multidimensional field settings, a set of experiments were conducted in a two-dimensional tank. The experiments are designed specifically to further improve our understanding of the effects of geologic heterogeneity on gas leakage. A two-dimensional tall tank with dimensions of 2.44m (H) x 0.41m (W) x 0.08m (D) was constructed. The tank was instrumented with 18 soil moisture sensors to measure the gas fraction and eight of which also measures temperature and electrical conductivity (EC). Pressure in the water phase was also measured at eight elevations along the length of the tank. The tank was packed with two test sands with known hydraulic and retention characteristics in a staggered pattern. The permeability of the coarser sand is roughly four times higher than that of the finer sand. There is no significant difference in porosity between the two sands. To simulate leakage from storage, gas-phase CO2 was injected at the bottom of the tank at a pressure of 35-70 kPa for durations changing from 6-24 hours. Soil moisture, EC, temperature, and water pressure were monitored during the experiment. It was observed that the gas phase CO2 first developed a preferential pathway mainly through the coarse soil. The data gathered from the pressure probes showed a significant pressure build-up during the gas injection, and a slow decrease after the gas injection was stopped. A qualitative analysis of the data from this single experiment shows; it took an hour, before CO2 was dissolved in a significant amount to be measured by an increase the electrical conduct of the fluid, however was this severely depending on the temperature. The two-phase system increases the water pressure, there is observed a direct correlation, between soil moisture content and water pressure. The heterogeneity was controlling the path of the CO2 gas. Additional experiments will be conducted to generate a comprehensive data set to evaluate the ability to existing multiphase modelling codes to capture the pressure changes observed in heterogeneous formations during CO2 leakage.

Lassen, R. N.; Sakaki, T.; Plampin, M. R.; Pawar, R. J.; Jensen, K. H.; Sonnenborg, T.; Illangasekare, T. H.

2011-12-01

34

Volcanic rises on Venus: Geology, formation, and sequence of evolution  

NASA Astrophysics Data System (ADS)

Large centers of volcanism on Venus are concentrated primarily in the equatorial region of the planet and are associated with regional topographic rises. Analysis of both radar images and geophysical data suggest that these uplands are sites of mantle upwelling. Magellan radar imaging provides a globally contiguous data set from which the geology of these regions is evaluated and compared. In addition, high resolution gravity data currently being collected provide a basis to assess the relationship between these uplands and processes in the planet's interior. Studies of the geology of the three largest volcanic highlands (Beta Regio, Atla Regio, Western Eistla Regio) show them to be distinct, having a range of volcanic and tectonic characteristics. In addition to these large areas, a number of smaller uplands are identified and are being analyzed (Bell Regio, Imdr Regio, Dione Regio (Ushas, Innini, and Hathor Montes), and Themis Regio). To understand better the mechanisms by which these volcanic rises form and evolve, we assess their geologic and geophysical characteristics.

Senske, D. A.; Stofan, E. R.; Bindschadler, D. L.; Smrekar, S. E.

1993-03-01

35

Geologically based model of heterogeneous hydraulic conductivity in an alluvial setting  

Microsoft Academic Search

Information on sediment texture and spatial continuity are inherent to sedimentary depositional facies descriptions, which\\u000a are therefore potentially good predictors of spatially varying hydraulic conductivity (K). Analysis of complex alluvial heterogeneity\\u000a in Livermore Valley, California, USA, using relatively abundant core descriptions and field pumping-test data, demonstrates\\u000a a depositional-facies approach to characterization of subsurface heterogeneity. Conventional textural classifications of the\\u000a core

Graham E. Fogg; Charles D. Noyes; Steven F. Carle

1998-01-01

36

Pattern formation by local amplification and lateral inhibition: Examples from biology and geology  

NASA Astrophysics Data System (ADS)

Pattern formation by local amplification and lateral inhibition is a common process in nature, responsible for regular repetition in many biological and geological systems. This conceptual framework provides a high-level understanding of self-organization, but also guides the search for the fundamental, local interactions in any given system. Several examples of pattern formation by lateral inhibition in sociology, biology and geology illustrate the general principles. In particular, we used this research methodology consciously for addressing the problem of rimstone (travertine terrace) formation. The statistical identification of spacing patterns is illustrated by an analysis of a pockmark field in the North Sea.

Hammer, Ø.

2009-11-01

37

AStudy of the Relationship of Geological Formation to the Norm.  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During the eleventh quarter of this project, emphasis again remained on two major tasks; identifying new sampling sites and seeking approval for final project revisions. In light of the delays experienced, the project has been granted a one year extension, and a revision is currently under review.

Bursh, T.P.; Derald Chriss

1997-07-08

38

Color heterogeneity of the surface of PHOBOS - Relationships to geologic features and comparison to meteorite analogs  

NASA Astrophysics Data System (ADS)

Color ratio images created from multispectral observations of Phobos are analyzed in order to characterize the spectral properties of Phobos' surface, to assess their spatial distributions and relationships with geologic features, and to compare Phobos' surface materials with possible meteorite analogs. Data calibration and processing is briefly discussed, and the observed spectral properties of Phobos and their lateral variations are examined. Attention is then given to the color properties of different types of impact craters, the origin of lateral variations in surface color, the relation between the spatial distribution of color properties and independently identifiable geologic features, and the relevance of color variation spatial distribution to the origin of the grooves.

Murchie, S. L.; Britt, D. T.; Head, J. W.; Pratt, S. F.; Fisher, P. C.; Zhukov, B. S.; Kuzmin, A. A.; Ksanfomality, L. V.; Zharkov, A. V.; Nikitin, G. E.; Fanale, F. P.; Blaney, D. L.; Bell, J. F.; Robinson, M. S.

1991-04-01

39

Fundamental Study on the Dynamics of Heterogeneity-Enhanced CO2 Gas Evolution in the Shallow Subsurface During Possible Leakage from Deep Geologic Storage Sites  

NASA Astrophysics Data System (ADS)

A concern for geologic carbon sequestration is the potential for CO2 stored in deep geologic formations to leak upward into shallow freshwater aquifers where it can have potentially detrimental impacts to the environment and human health. Understanding the mechanisms of CO2 exsolution, migration and accumulation (collectively referred to as 'gas evolution') in the shallow subsurface is critical to predict and mitigate the environmental impacts. During leakage, CO2 can move either as free-phase or as a dissolved component of formation brine. CO2 dissolved in brine may travel upward into shallow freshwater systems, and the gas may be released from solution. In the shallow aquifer, the exsolved gas may accumulate near interfaces between soil types, and/or create flow paths that allow the gas to escape through the vadose zone to the atmosphere. The process of gas evolution in the shallow subsurface is controlled by various factors, including temperature, dissolved CO2 concentration, water pressure, background water flow rate, and geologic heterogeneity. However, the conditions under which heterogeneity controls gas phase evolution have not yet been precisely defined and can therefore not yet be incorporated into models used for environmental risk assessment. The primary goal of this study is to conduct controlled laboratory experiments to help fill this knowledge gap. With this as a goal, a series of intermediate-scale laboratory experiments were conducted to observe CO2 gas evolution in porous media at multiple scales. Deionized water was saturated with dissolved CO2 gas under a specified pressure (the saturation pressure) before being injected at a constant volumetric flow rate into the bottom of a 1.7 meter-tall by 5.7 centimeter-diameter column or a 2.4 meter-tall by 40 centimeter-wide column that were both filled with sand in various heterogeneous packing configurations. Both test systems were initially saturated with fresh water and instrumented with soil moisture sensors to monitor the evolution of gas phase through time by measuring the average water content in small sampling volumes of soil. Tensiometers allowed for observation of water pressure through space and time in the test systems, and a computer-interfaced electronic scale continuously monitored the outflow of water from the top of the two test columns. Several packing configurations with five different types of sands were used in order to test the effects of various pore size contrasts and interface shapes on the evolution of the gas phase near soil texture transitions in the heterogeneous packings. Results indicate that: (1) heterogeneity affects gas phase evolution patterns within a predictable range of conditions quantified by the newly introduced term 'oversaturation,' (2) soil transition interfaces where less permeable material overlies more permeable material have a much more pronounced effect on gas evolution than interfaces with opposite orientations, and (3) anticlines (or stratigraphic traps) cause significantly greater gas accumulation than horizontal interfaces. Further work is underway to apply these findings to more realistic, two-dimensional scenarios, and to assess how well existing numerical models can capture these processes.

Plampin, M. R.; Lassen, R. N.; Sakaki, T.; Pawar, R.; Jensen, K.; Illangasekare, T. H.

2013-12-01

40

River-aquifer interactions, geologic heterogeneity, and low-flow management  

USGS Publications Warehouse

Low river flows are commonly controlled by river-aquifer exchange, the magnitude of which is governed by hydraulic properties of both aquifer and aquitard materials beneath the river. Low flows are often important ecologically. Numerical simulations were used to assess how textural heterogeneity of an alluvial system influences river seepage and low flows. The Cosumnes River in California was used as a test case. Declining fall flows in the Cosumnes River have threatened Chinook salmon runs. A ground water-surface water model for the lower river basin was developed, which incorporates detailed geostatistical simulations of aquifer heterogeneity. Six different realizations of heterogeneity and a homogenous model were run for a 3-year period. Net annual seepage from the river was found to be similar among the models. However, spatial distribution of seepage along the channel, water table configuration and the level of local connection, and disconnection between the river and aquifer showed strong variations among the different heterogeneous models. Most importantly, the heterogeneous models suggest that river seepage losses can be reduced by local reconnections, even when the regional water table remains well below the riverbed. The percentage of river channel responsible for 50% of total river seepage ranged from 10% to 26% in the heterogeneous models as opposed to 23% in the homogeneous model. Differences in seepage between the models resulted in up to 13 d difference in the number of days the river was open for salmon migration during the critical fall months in one given year. Copyright ?? 2006 The Author(s).

Fleckenstein, J. H.; Niswonger, R. G.; Fogg, G. E.

2006-01-01

41

Permafrost on Mars: distribution, formation, and geological role  

NASA Technical Reports Server (NTRS)

The morphology of channels, valleys, chaotic and fretted terrains and many smaller features on Mars is consistent with the hypothesis that localized deterioration of thick layers of ice-rich permafrost was a dominant geologic process on the Martian surface. Such ground ice deterioration gave rise to large-scale mass movement, including sliding, slumping and sediment gravity flowage, perhaps also catastropic floods. In contrast to Earth, such mass movement processes on Mars lack effective competition from erosion by surface runoff. Therefore, Martian features due to mass movement grew to reach immense size without being greatly modified by secondary erosional processes. The Viking Mission to Mars in 1976 provided adequate measurements of the relevant physical parameters to constrain models for Martian permafrost.

Nummedal, D.

1984-01-01

42

Estimation of geological dip and curvature from time-migrated zero-offset reflections in heterogeneous  

E-print Network

Estimation of geological dip and curvature from time-migrated zero-offset reflections ABSTRACT Starting from a given time-migrated section and time migrated velocity field, recent litera- ture-velocity model along them. This, in turn, allows image-ray migration, namely to map time-migrated horizons

Ursin, Bjørn

43

Heterogeneous nucleation and microstructure formation in colloidal model systems with various interactions  

NASA Astrophysics Data System (ADS)

Recent studies of crystal nucleation and further microstructure formation in colloidal model systems are reviewed. Homogeneous as well as different heterogeneous nucleation scenarios will be discussed. We focus on the crystallization process of one component colloidal model systems with hard sphere like interaction, long range electrostatic interaction and depletion force induced attractive interaction. Heterogeneous crystallization on flat and smooth substrates, on structured substrates, induced by different kind of seed particles as well as inoculation adding a larger amount of seeds will be presented.

Lederer, A.; Franke, M.; Schöpe, H. J.

2014-02-01

44

An erbium-based bifuctional heterogeneous catalyst: a cooperative route towards C-C bond formation.  

PubMed

Heterogeneous bifuctional catalysts are multifunctional synthetic catalysts enabling efficient organic transformations by exploiting two opposite functionalities without mutual destruction. In this paper we report the first Er(III)-based metallorganic heterogeneous catalyst, synthesized by post-calcination MW-assisted grafting and modification of the natural aminoacid L-cysteine. The natural acid-base distance between sites was maintained to assure the cooperation. The applicability of this new bifunctional heterogeneous catalyst to C-C bond formation and the supposed mechanisms of action are discussed as well. PMID:25029070

Oliverio, Manuela; Costanzo, Paola; Macario, Anastasia; De Luca, Giuseppina; Nardi, Monica; Procopio, Antonio

2014-01-01

45

Approaches to large scale unsaturated flow in heterogeneous, stratified, and fractured geologic media  

SciTech Connect

This report develops a broad review and assessment of quantitative modeling approaches and data requirements for large-scale subsurface flow in radioactive waste geologic repository. The data review includes discussions of controlled field experiments, existing contamination sites, and site-specific hydrogeologic conditions at Yucca Mountain. Local-scale constitutive models for the unsaturated hydrodynamic properties of geologic media are analyzed, with particular emphasis on the effect of structural characteristics of the medium. The report further reviews and analyzes large-scale hydrogeologic spatial variability from aquifer data, unsaturated soil data, and fracture network data gathered from the literature. Finally, various modeling strategies toward large-scale flow simulations are assessed, including direct high-resolution simulation, and coarse-scale simulation based on auxiliary hydrodynamic models such as single equivalent continuum and dual-porosity continuum. The roles of anisotropy, fracturing, and broad-band spatial variability are emphasized. 252 refs.

Ababou, R.

1991-08-01

46

Geology of the Grand Canyon: Interpreting its rock layers and formation  

NSDL National Science Digital Library

In this culminating activity, students will be assessed on what they have learned during the Geology unit of their Earth Science class. After conducting classroom and field studies on geology students will utilize this knowledge to interpret the rock layers and formation of the Grand Canyon. Outside of class students will read/review a website and complete a study guide to be reviewed by the teacher to assess students' learning. Following teacher review of study guides, the next class period(s) will be a discussion and questioning session(s) on the formation of the Grand Canyon.

47

Enhanced CO2 Storage in Confined Geologic Formations  

Microsoft Academic Search

Many geoscientists endorse Carbon Capture and Storage (CCS) as a potential strategy\\u000afor mitigating emissions of greenhouse gases. Deep saline aquifers have been reported to\\u000ahave larger CO\\u000a2 storage capacity than other formation types because of their availability\\u000aworldwide and less competitive usage. This work proposes an analytical model for screening\\u000apotential CO\\u000a2 storage sites and investigates injection

Roland Tenjoh Okwen

2009-01-01

48

Thermal state and complex geology of a heterogeneous salty crust of Jupiter's satellite, Europa  

USGS Publications Warehouse

The complex geology of Europa is evidenced by many tectonic and cryomagmatic resurfacing structures, some of which are "painted" into a more visible expression by exogenic alteration processes acting on the principal endogenic cryopetrology. The surface materials emplaced and affected by this activity are mainly composed of water ice in some areas, but in other places there are other minerals involved. Non-ice minerals are visually recognized by their low albedo and reddish color either when first emplaced or, more likely, after alteration by Europan weathering processes, especially sublimation and alteration by ionizing radiation. While red chromophoric material could be due to endogenic production of solid sulfur allotropes or other compounds, most likely the red substance is an impurity produced by radiation alteration of hydrated sulfate salts or sulphuric acid of mainly internal origin. If the non-ice red materials or their precursors have a source in the satellite interior, and if they are not merely trace contaminants, then they can play an important role in the evolution of the icy crust, including structural differentiation and the internal dynamics. Here we assume that these substances are major components of Europa's cryo/hydrosphere, as some models have predicted they should be. If this is an accurate assumption, then these substances should not be neglected in physical, chemical, and biological models of Europa, even if major uncertainties remain as to the exact identity, abundance, and distribution of the non-ice materials. The physical chemical properties of the ice-associated materials will contribute to the physical state of the crust today and in the geological past. In order to model the influence of them on the thermal state and the geology, we have determined the thermal properties of the hydrated salts. Our new lab data reveal very low thermal conductivities for hydrated salts compared to water ice. Lower conductivities of salty ice would produce steeper thermal gradients than in pure ice. If there are salt-rich layers inside the crust, forming salt beds over the seafloor or a briny eutectic crust, for instance, the high thermal gradients may promote endogenic geological activity. On the seafloor, bedded salt accumulations may exhibit high thermochemical gradients. Metamorphic and magmatic processes and possible niches for thermophilic life at shallow suboceanic depths result from the calculated thermal profiles, even if the ocean is very cold. ?? 2004 Elsevier Inc. All rights reserved.

Prieto-Ballesteros, O.; Kargel, J.S.

2005-01-01

49

Geology  

NSDL National Science Digital Library

With three levels to choose from on each page - beginner, intermediate or advanced - this site provides information on the many different kinds of geological exploration. The elements that make up minerals and the different ways minerals are developed, The special characteristics of minerals, like physical properties, is explained. Earths tectonic plates, the reasons they move, and the effects of the shifting are also given. Also featured is fossils and how they are developed and are found, as well as why fossils are useful tools for scientists.

Bergman, Jennifer

2009-08-03

50

Method and device with adjustable focusing for measuring the electric resistivity of geological formations  

SciTech Connect

The method of the invention comprises determining the variation of the electric potential on both sides of a central electrode in a borehole, detecting the two levels of the borehole where the potential gradient is zero, and measuring the electric resistivity of the geological formation between these two levels.

Desbrandes, R.

1983-10-25

51

Heterogeneous Mobile Sensor Net Deployment Using Robot Herding and Line-of-Sight Formations  

E-print Network

Heterogeneous Mobile Sensor Net Deployment Using Robot Herding and Line-of-Sight Formations Lynne E to limited sensing capabilities, neither of these helper robots can herd the mobile sensor nodes alone of robot team hetero- geneity in the context of mobile sensor net deployment in an indoor environment

Parker, Lynne E.

52

Sedimentological and Petrophysical Heterogeneity of Glaciogenic Paleovalley, Late Ordovician Sarah Formation, Central Saudi Arabia  

NASA Astrophysics Data System (ADS)

The Late Ordovician Sarah Formation deposited in glaciogenic environment, mainly dominated by braided river outwash system. Compared to the subsurface, the Sarah formation is considered as important tight gas sandstone reservoir at southern and northern parts of Saudi Arabia. Ten outcrops from Al-Ilb paleochannel were studied in detail to identify the heterogeneity in terms of the types and distribution of facies and related petrophysical properties. The Sarah Formation shows highly heterogeneous behavior at all scales. The main facies observed at Al-Ilb paleovalley are 64% trough-cross bedded sandstone, 23% horizontally stratified sandstone facies, and 2% massive conglomerates are observed at the proximal, medial and distal parts of the paleovalley. The remaining facies are trough-cross bedded sandstone facies that is laterally changes to horizontally stratified sandstone facies and in some cases to planner cross-bedded sandstone facies. The petrophysical analysis revealed good quality of porosity present in all parts of paleovalley. On the other hand the permeability values are high and ranging between 53mD to 5D. The descriptive statistics clearly indicate the normal distribution of porosity values for proximal, medial and distal parts of paleovalley and can be described as homogeneous. For permeability the distribution is heterogeneous as it is log-normally distributed. The scatter plots of porosity versus horizontal and vertical permeability shows very poor correlation for each part of paleochannel. This heterogeneity is attributed to depositional and post-depositional viabilities. These variables are grain size and shape distribution, sorting, packing, distribution of matrix and cementing material, and the presence of clays like kaolinite, smectite, and palygorskite. These observations further indicate that Sarah Formation is affected by shallow burial conditions during diagenesis. However, Sarah Formation shows highly heterogeneous behavior at outcrop scale that might be unpredictable and challenging in the subsurface.

Razzaq, Waseem; Abdullatif, Osman; Sahin, Ali; Hariri, Mustafa

2014-05-01

53

Geological conditions of the time of formation of impact craters on Pai-Khoi  

NASA Astrophysics Data System (ADS)

Present-day ideas on the time of formation of the Kara and Ust-Kara astroblemes are presented, and the main features of the geological structure of Phai-Khoi (the region where these structures are located) are described. Based on an analysis of the geological conditions, a large complex of fossil fauna and diatomaceous algae, and radiological dating of tagamites and impact glasses, it is shown that the craters were formed on the Cretaceous-Paleogene boundary about 66-67 million years ago.

Mashchak, M. S.

54

Heterogeneity and Reservoir Quality of Yabus and Samaa Formations, Agordeed Field, Melut Rift Basin, Sudan  

NASA Astrophysics Data System (ADS)

The Tertiary Yabus and Samaa Formations occur within the Melut Rift basin of interior Sudan which is regionally linked to the central and west African rift system. Yabus and Samaa Formations in Agordeed oil field are ones of the most productive oil reservoirs in Melut basin and are composed of sandstones and mudstones lithofacies that differ in size and length along and across the basin. The reservoir sandstone, which occurs at shallow burial depth, deposited within fluvial/lacustrine environments. This work aims to describe and characterize the reservoir heterogeneity and to investigate their impact on reservoir quality and architecture. This study employed a multidisciplinary and integrated approach that investigated and synthesized stratigraphic, sedimentological, cores, logs, petrographical, petrophysical and seismic data from Agordeed oil field. The stratigraphic and lithofacies analysis indicated that Yabus and Samaa formations vary systematically in their facies, sequences and stacking patterns within the basin. Reservoir heterogeneity exists at multiple scales, where reservoir sandstones macro- and micro scale heterogeneity shows vertical and lateral variations along and across the basin. These variations reflect the tectonic, depositional and post depositional controls within the proximal to distal fluvial, prodelta and lacustrine environments. The porosity and permeability distributions are controlled by the heterogeneities within the reservoir formation, such as stratigraphic layering, facies, diagenetic processes, and fracturing. Porosity is enhanced by extensive fracturing and grain dissolution creating intergranular, intragranular and moldic porosity. In addition, permeability is also increased by fractures connecting separated the buildups, that affect directly the reservoir quality. Assessing the different scales of heterogeneity is important to understand their impact on reservoir quality and architecture in Agordeed Field.

Badi, Amani; Ali, Omer; Farwa, Abdalla; Abdullatif, Osman

2010-05-01

55

The Impact of Geologic Heterogeneity on CO2 Injection with Simultaneous Brine Extraction and Economic Uncertainty for Large-Scale CO2 Sequestration  

NASA Astrophysics Data System (ADS)

Performance assessment of CO2 sequestration opportunities at the scale of the United States presents challenges for coping with geologic and economic uncertainties. Inaccurate estimation of suitable flow properties could result in drilling wells in parts of a formation that could not physically accommodate the needed injection rates and storage volumes. Data paucity and heterogeneity in geologic properties necessitates probabilistic approaches for estimating CO2 injection and simultaneous brine extraction rates (for beneficial use such as power-plant cooling or pressure management) and associated costs. We present an Integrated Assessment Model (IAM) that assesses CO2 injection rates with or without simultaneous brine extraction for the saline reservoirs identified in the National Carbon Sequestration Database (NatCarb). We have linked NatCarb reservoirs to injectivity rock types. We define these rock types quantitatively by probability distribution functions (PDFs) of permeability and porosity, and spatial correlation models. Thus, IAM has flexibility in calculating CO2 injectivity and brine productivity while coping with heterogeneity, and then determining the uncertainty in well-associated costs. For computational efficiency, IAM performs injectivity and productivity calculations with analytical solutions that have been validated by numerical simulation and comparison to available field data. The solutions incorporate spatially varying properties through PDFs that are based on upscaling of geostatistical realizations of the injectivity rock types. A key method of the geostatistics is linear coregionalization, which defines the linear relationship between porosity and log permeability with a specified correlation coefficient, r, of the regression while maintaining the spatial correlation of each variable. The major finding is high sensitivity of well-associated costs to permeability. Error in field prediction of an order of magnitude in permeability may be the difference between an economically and physically viable or unfeasible site due to potentially order of magnitude change in the number of required injection wells. Finally, we present the affects of varying the correlation between permeability and porosity on injectivity and productivity estimates. 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.

Kobos, P. H.; Heath, J. E.; Roach, J. D.; McKenna, S. A.; Dewers, T. A.; Gutierrez, K.

2011-12-01

56

Paleomagnetic dating of continental geological formations: Strong diachronism evidenced in the Saharan platform and geodynamical implications  

NASA Astrophysics Data System (ADS)

The paleomagnetism is a powerful tool to date formations that have age not constrained by paleontological, stratigraphical or radiochronological data. It was applied, on the western border of the Murzuq basin in Algeria (Saharan platform), to the Zarzaïtine formation, attributed to a Middle-Upper Triassic-Lower Jurassic age. Comparison of the obtained paleomagnetic pole with previous poles from the same geological formation outcropping in another basin and from other Carboniferous to Lower Mesozoic African formations yielded a clearly older age (Late Permian) than expected. That evidences a strong diachronism (at least 40 My) of the deposition of this formation on the Saharan platform. The post-Hercynian structural evolution was therefore different according to the parts of this platform, with significant differential vertical tectonic movements. The latter were at the origin of erosion, hiatus or sediments deposition according to areas.

Henry, B.; Derder, M. E. M.; Amenna, M.; Maouche, S.; Bayou, B.; Ouabadi, A.; Bouabdallah, H.; Beddiaf, M.; Ayache, M.; Bestandji, R.

2014-11-01

57

Methods and apparatus for measurement of electronic properties of geological formations through borehole casing  

DOEpatents

Methods and apparatus are provided for measuring electronic properties of geological formations and cement layers adjacent to cased boreholes including resistivities, polarization phenomena and dielectric constants. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. At least three voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the differential current conducted into formation in the vicinity of those electrodes. These measurements facilitate calculation of the resistivities of the adjacent geological formations as well as an indication of whether cement is present. Measurements of the differential voltage response to transient currents provide a measurement of the polarization phenomena in formation as well as the capacitance of the casing in contact with the formation which is useful for determining whether oil and gas present. Lithological characteristics of the formation such as the pressence or absence of clay can also be determined. A calibration procedure is provided for minimizing errors induced by variations in the casing. The device also may be placed within the pipe attached to a drill bit while drilling open holes.

Vail, III, William B. (Bothell, WA)

1991-01-01

58

Methods and apparatus for measurement of electronic properties of geological formations through borehole casing  

DOEpatents

Methods and apparatus are provided for measuring electronic properties of geological formations and cement layers adjacent to cased boreholes including resistivities, polarization phenomena and dielectric constants. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. At least three voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of differential current conducted into formation in the vicinity of those electrodes. These measurements facilitate calculation of the resistivities of the adjacent geological formations as well as an indication of whether cement is present. Measurements of the differential voltage response to transient currents provide a measurement of the polarization phenomena in formation as well as the capacitance of the casing in contact with the formation which is useful for determining whether oil and gas are present. Lithological characteristics of the formation such as the presence or absence of clay can also be determined. A calibration procedure is provided for minimizing errors induced by variations in the casing. The device also may be placed within the pipe attached to a drill bit while drilling open holes.

Vail, III, William B. (Bothell, WA)

1989-01-01

59

Methods and apparatus for measurement of the resistivity of geological formations from within cased boreholes  

DOEpatents

Methods and apparatus are disclosed which allow measurement of the resistivity of a geological formation through borehole casing which may be surrounded by brine saturated cement. A.C. current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. The A.C. voltage difference is measured between two additional vertically disposed electrodes on the interior of the casing which provides a measure of the resistivity of the geological formation. A calibration and nulling procedure is presented which minimizes the influence of variations in the thickness of the casing. The procedure also minimizes the influence of inaccurate placements of the additional vertically disposed electrodes.

Vail, III, William B. (Bothell, WA)

1989-01-01

60

Method for Controlling a Producing Zone of a Well in a Geological Formation  

NASA Technical Reports Server (NTRS)

System and methods for transmitting and receiving electromagnetic pulses through a geological formation. A preferably programmable transmitter having an all-digital portion in a preferred embodiment may be operated at frequencies below 1 MHz without loss of target resolution by transmitting and over sampling received long PN codes. A gated and stored portion of the received signal may be correlated with the PN code to determine distances of interfaces within the geological formation, such as the distance of a water interfaces from a wellbore. The received signal is oversampled preferably at rates such as five to fifty times as high as a carrier frequency. In one method of the invention, an oil well with multiple production zones may be kept in production by detecting an approaching water front in one of the production zones and shutting down that particular production zone thereby permitting the remaining production zones to continue operating.

Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Byerly, Kent A. (Inventor); Amini, B. Jon (Inventor)

2005-01-01

61

Method for controlling a producing zone of a well in a geological formation  

NASA Technical Reports Server (NTRS)

System and methods for transmitting and receiving electromagnetic pulses through a geological formation. A preferably programmable transmitter having an all-digital portion in a preferred embodiment may be operated at frequencies below 1 MHz without loss of target resolution by transmitting and over sampling received long PN codes. A gated and stored portion of the received signal may be correlated with the PN code to determine distances of interfaces within the geological formation, such as the distance of a water interfaces from a wellbore. The received signal is oversampled preferably at rates such as five to fifty times as high as a carrier frequency. In one method of the invention, an oil well with multiple production zones may be kept in production by detecting an approaching water front in one of the production zones and shutting down that particular production zone thereby permitting the remaining production zones to continue operating.

Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Byerly, Kent A. (Inventor); Amini, B. Jon (Inventor)

2005-01-01

62

Regulatory Constraints to Carbon Sequestration in Terrestrial Ecosystems and Geologic Formations: A California Perspective  

Microsoft Academic Search

Carbon sequestration in terrestrialecosystems and geologic formations providesa significant opportunity for California toaddress global climate change. The physicalsize of its resources (e.g., forests,agriculture, soils, rangeland, and geologicformations) and the expertise in Californiaprovides a substantial foundation fordeveloping carbon sequestration activities.Furthermore, the co-benefits of carbonsequestration – such as improved soil andwater quality, restoration of degradedecosystems, increased plant and cropproductivity, and enhanced oil

Edward Vine

2004-01-01

63

Experiences with the Application of Services Oriented Approaches to the Federation of Heterogeneous Geologic Data Resources  

NASA Astrophysics Data System (ADS)

The federation of databases is not a new endeavor. Great strides have been made e.g. in the health and astrophysics communities. Reviews of those successes indicate that they have been able to leverage off key cross-community core concepts. In its simplest implementation, a federation of databases with identical base schemas that can be extended to address individual efforts, is relatively easy to accomplish. Efforts of groups like the Open Geospatial Consortium have shown methods to geospatially relate data between different sources. We present here a summary of CHRONOS's (http://www.chronos.org) experience with highly heterogeneous data. Our experience with the federation of very diverse databases shows that the wide variety of encoding options for items like locality, time scale, taxon ID, and other key parameters makes it difficult to effectively join data across them. However, the response to this is not to develop one large, monolithic database, which will suffer growth pains due to social, national, and operational issues, but rather to systematically develop the architecture that will enable cross-resource (database, repository, tool, interface) interaction. CHRONOS has accomplished the major hurdle of federating small IT database efforts with service-oriented and XML-based approaches. The application of easy-to-use procedures that allow groups of all sizes to implement and experiment with searches across various databases and to use externally created tools is vital. We are sharing with the geoinformatics community the difficulties with application frameworks, user authentication, standards compliance, and data storage encountered in setting up web sites and portals for various science initiatives (e.g., ANDRILL, EARTHTIME). The ability to incorporate CHRONOS data, services, and tools into the existing framework of a group is crucial to the development of a model that supports and extends the vitality of the small- to medium-sized research effort that is essential for a vibrant scientific community. This presentation will directly address issues of portal development related to JSR-168 and other portal API's as well as issues related to both federated and local directory-based authentication. The application of service-oriented architecture in connection with ReST-based approaches is vital to facilitate service use by experienced and less experienced information technology groups. Application of these services with XML- based schemas allows for the connection to third party tools such a GIS-based tools and software designed to perform a specific scientific analysis. The connection of all these capabilities into a combined framework based on the standard XHTML Document object model and CSS 2.0 standards used in traditional web development will be demonstrated. CHRONOS also utilizes newer client techniques such as AJAX and cross- domain scripting along with traditional server-side database, application, and web servers. The combination of the various components of this architecture creates an environment based on open and free standards that allows for the discovery, retrieval, and integration of tools and data.

Cervato, C.; Fils, D.; Bohling, G.; Diver, P.; Greer, D.; Reed, J.; Tang, X.

2006-12-01

64

Evidence for precursor plasma formation resulting from heterogeneous current channels in wire array loads  

Microsoft Academic Search

The initial current flow in single and double wire loads exploded by current generators with dI\\/dt in the range of 1010–1012 A\\/s has been investigated using laser absorption and interferometric techniques. The results clearly show heterogeneous current channel formation with a plasma corona surrounding a predominantly neutral core. In the two wire load case, the corona is observed to separate

E. J. Yadlowsky; J. J. Moschella; R. C. Hazelton; T. B. Settersten; G. G. Spanjers; C. Deeney; B. H. Failor; P. D. Lepell; J. Davis; J. P. Apruzese; K. G. Whitney; J. W. Thornhill

1996-01-01

65

Numerical evaluation of apparent transport parameters from forced-gradient tracer tests in statistically anisotropic heterogeneous formations  

NASA Astrophysics Data System (ADS)

For risk assessment and adequate decision making regarding remediation strategies in contaminated aquifers, solute fate in the subsurface must be modeled correctly. In practical situations, hydrodynamic transport parameters are obtained by fitting procedures, that aim to mathematically reproduce solute breakthrough (BTC) observed in the field during tracer tests. In recent years, several methods have been proposed (curve-types, moments, nonlocal formulations) but none of them combine the two main characteristic effects of convergent flow tracer tests (which are the most used tests in the practice): the intrinsic non-stationarity of the convergent flow to a well and the ubiquitous multiscale hydraulic heterogeneity of geological formations. These two effects separately have been accounted for by a lot of methods that appear to work well. Here, we investigate both effects at the same time via numerical analysis. We focus on the influence that measurable statistical properties of the aquifers (such as the variance and the statistical geometry of correlation scales) have on the shape of BTCs measured at the pumping well during convergent flow tracer tests. We built synthetic multigaussian 3D fields of heterogeneous hydraulic conductivity fields with variable statistics. A well is located in the center of the domain to reproduce a forced gradient towards it. Constant-head values are imposed on the boundaries of the domains, which have 251x251x100 cells. Injections of solutes take place by releasing particles at different distances from the well and using a random walk particle tracking scheme with constant local coefficient of dispersivity. The results show that BTCs partially display the typical anomalous behavior that has been commonly referred to as the effect of heterogeneity and connectivity (early and late arrival times of solute differ from the one predicted by local formulations). Among the most salient features, the behaviors of BTCs after the peak (the slope of the BTCs in log-log scales, which is the diagnostic plot to infer power-law type nonlocal distribution parameters due to hydraulic heterogeneity) indicate that anisotropy generates apparent higher capacity coefficients in certain directions. At very late times, however, the slopes display similar values, indicating that at these spatial scales (injection distances comparable with the integral scales), particles are stacked in low K areas for much longer than the advection times in higher K zones.

Pedretti, D.; Fernandez-Garcia, D.; Bolster, D.; Sanchez-Vila, X.; Benson, D.

2012-04-01

66

Universitt Stuttgart Institut fr Wasserbau, Lehrstuhl fr Hydromechanik und Hydrosystemmodellierung "Numerical Simulation of CO2 Sequestration in Geological Formations", CMWR Copenhagen, June 20, 2006  

E-print Network

Hydrosystemmodellierung "Numerical Simulation of CO2 Sequestration in Geological Formations", CMWR Copenhagen, June 20, 2006 Reliability of numerical models for simulating CO2 storage in deep geological formations Holger Hydromechanik und Hydrosystemmodellierung "Numerical Simulation of CO2 Sequestration in Geological Formations

Cirpka, Olaf Arie

67

Universitt StuttgartInstitut fr Wasserbau, Lehrstuhl fr Hydromechanik und Hydrosystemmodellierung Workshop on Numerical Models for Carbon Dioxide Storage in Geological Formations  

E-print Network

Hydrosystemmodellierung Workshop on Numerical Models for Carbon Dioxide Storage in Geological Formations 1/16 Modelling April 2008 Workshop on Numerical Models for Carbon Dioxide Storage in Geological Formations #12 on Numerical Models for Carbon Dioxide Storage in Geological Formations 2/16 CO2 leakage mitigation using

Cirpka, Olaf Arie

68

A methodology for the geological and numerical modelling of CO2 storage in deep saline formations  

NASA Astrophysics Data System (ADS)

Several technological options have been proposed to stabilize and reduce the atmospheric concentrations of CO2 among which the most promising are the CCS technologies. The remedy proposed for large stationary CO2 sources as thermoelectric power plants is to separate the flue gas, capturing CO2 and to store it into deep subsurface geological formations. In order to support the identification of potential CO2 storage reservoirs in Italy, the project "Identification of Italian CO2 geological storage sites", financed by the Ministry of Economic Development with the Research Fund for the Italian Electrical System under the Contract Agreement established with the Ministry Decree of march 23, 2006, has been completed in 2008. The project involves all the aspects related to the selection of potential storage sites, each carried out in a proper task. The first task has been devoted to the data collection of more than 6800 wells, and their organization into a geological data base supported by GIS, of which 1911 contain information about the nature and the thickness of geological formations, the presence of fresh, saline or brackish water, brine, gas and oil, the underground temperature, the seismic velocity and electric resistance of geological materials from different logs, the permeability, porosity and geochemical characteristics. The goal of the second task was the set up of a numerical modelling integrated tool, that is the in order to allow the analysis of a potential site in terms of the storage capacity, both from solubility and mineral trapping points of view, in terms of risk assessment and long-term storage of CO2. This tool includes a fluid dynamic module, a chemical module and a module linking a geomechanical simulator. Acquirement of geological data, definition of simulation parameter, run control and final result analysis can be performed by a properly developed graphic user interface, fully integrated and calculation platform independent. The project is then completed by a public acceptance task. The paper presents the outlines of the project, the geological data base characteristics and the description of the integrated numerical modelling tool pointed out; showing also an application to a potential Italian site in Adriatic offshore area.

Guandalini, R.; Moia, F.; Ciampa, G.; Cangiano, C.

2009-04-01

69

Geologic Sequestration of CO2: Potential Permeability Changes in Host Formations of the San Juan Basin, New Mexico  

Microsoft Academic Search

Terrestrial sequestration through injection into geologic formations is one proposed method for the isolation of anthropogenic CO2 from the atmosphere. A variety of physical and chemical processes are known to occur both during and after geologic CO2 injection, including diagenetic chemical reactions and associated permeability changes. Although it is commonly assumed that CO2 sequestered in this way will ultimately become

A. P. Abel; B. McPherson; P. Lichtner; G. Bond; J. Stringer; R. Grigg

2002-01-01

70

Vertical stratification of subsurface microbial community composition across geological formations at the Hanford Site.  

PubMed

Microbial diversity in subsurface sediments at the Hanford Site 300 Area near Richland, Washington state (USA) was investigated by analysing 21 samples recovered from depths of 9-52?m. Approximately 8000 near full-length 16S rRNA gene sequences were analysed across geological strata that include a natural redox transition zone. These strata included the oxic coarse-grained Hanford formation, fine-grained oxic and anoxic Ringold Formation sediments, and the weathered basalt group. We detected 1233 and 120 unique bacterial and archaeal OTUs (operational taxonomic units at the 97% identity level) respectively. Microbial community structure and richness varied substantially across the different geological strata. Bacterial OTU richness (Chao1 estimator) was highest (>?700) in the upper Hanford formation, and declined to about 120 at the bottom of the Hanford formation. Just above the Ringold oxic-anoxic interface, richness was about 325 and declined to less than 50 in the deeper reduced zones. The deeper Ringold strata were characterized by a preponderance (c. 90%) of Proteobacteria. The bacterial community in the oxic sediments contained not only members of nine well-recognized phyla but also an unusually high proportion of three candidate divisions (GAL15, NC10 and SPAM). Additionally, 13 novel phylogenetic orders were identified within the Deltaproteobacteria, a clade rich in microbes that carry out redox transformations of metals that are important contaminants on the Hanford Site. PMID:22122741

Lin, Xueju; Kennedy, David; Fredrickson, Jim; Bjornstad, Bruce; Konopka, Allan

2012-02-01

71

Vertical stratification of subsurface microbial community composition across geological formations at the Hanford Site  

SciTech Connect

Microbial diversity in subsurface sediments at the Hanford Site 300 Area near Richland, Washington State (USA) was investigated by analyzing samples recovered from depths of 9 to 52 m. Approximately 8000 near full-length 16S rRNA gene sequences were analyzed across geological strata that include a natural redox transition zone. These strata included the oxic coarse-grained Hanford formation, fine-grained oxic and anoxic Ringold Formation sediments, and the weathered basalt group. We detected 1233 and 120 unique bacterial and archaeal OTUs (Operational Taxonomic Units at the 97% identity level), respectively. Microbial community structure and richness varied substantially across the different geological strata. Bacterial OTU richness (Chao1 estimator) was highest (>700) in the upper Hanford formation, and declined to about 120 at the bottom of the Hanford formation. Just above the Ringold oxic-anoxic interface, richness was about 325 and declined to less than 50 in the deeper reduced zones. The deeper Ringold strata were characterized by a preponderance (ca. 90%) of Proteobacteria. The Bacterial community in the oxic sediments contained not only members of 9 well-recognized phyla but also an unusually high proportion of 3 candidate divisions (GAL15, NC10, and SPAM). Additionally, novel phylogenetic orders were identified within the Delta-proteobacteria, a clade rich in microbes that carry out redox transformations of metals that are important contaminants on the Hanford Site.

Lin, Xueju; Kennedy, David W.; Fredrickson, Jim K.; Bjornstad, Bruce N.; Konopka, Allan

2011-11-29

72

Geologic Mapping Applications Using THEMIS Data for the Medusae Fossae Formation, Mars  

NASA Technical Reports Server (NTRS)

The Medusae Fossae Formation (MFF) is a regionally extensive deposit located along the equator of Mars between roughly 130 and 240 E longitude, the origin of which has stimulated a host of published hypotheses. A volcanic or aeolian origin appear most consistent with Viking and MGS data, but other hypotheses remain viable and new data, as from the Mars Odyssey spacecraft, is likely to stimulate additional hypotheses of origin. NASA is supporting geologic mapping of portions of the MFF deposits, but it is now quite clear that this on-going mapping will need considerable revision as data from the Thermal Emission Imaging System (THEMIS) on Mars Odyssey become available. The daytime IR THEMIS images hold particularly strong potential for providing a new base on which geologic mapping can be carried out, as illustrated by the examples discussed.

Zimbelman, J. R.; Bender, K. C.; Harris, J. C.

2003-01-01

73

Characterization of the Geologic Setting of Recurring Slope Lineae: Constraints on Their Formation Mechanism  

NASA Astrophysics Data System (ADS)

Recurring Slope Lineae (RSL) are seasonal, low albedo features that originate at the base of bedrock outcrops and extend down steep, equator-facing, mid-latitude and equatorial rocky slopes of Mars. They exhibit progressive growth in the downslope direction during warm seasons, diverting around topographic obstacles, and fade during cold seasons. Slopes containing RSL appear to be sites of geologically very recent activity, including 'fresh' impact craters and active mass wasting, and are also associated with numerous small channels and bright fans. Based on their seasonal growth and strong dependency on latitude and slope aspect, RSL formation has been attributed to the seepage and downslope transport of a salt-bearing (briny), water-based liquid (potentially melted) through porous regolith near the surface. The seepage of this liquid wets and thus darkens the RSL surface, and evaporates once seasonal flow ceases. However, the source of this water, and an active recharge mechanism to maintain this source over even short geological timescales, are not currently understood. Subsurface groundwater is one possible source for the amount of liquid required to fill pore spaces between particles and create a hydraulic gradient to initiate and maintain water flow to the surface. Preexisting structural inhomogeneities, including faults, fractures, and joints, may act as conduits for subsurface fluid migration, supporting groundwater exploitation of routes of increased permeability. To investigate this fault-controlled brine flow hypothesis, morphological mapping of RSL slope surfaces is performed. Preliminary analysis of these geologic settings suggests a spatial correlation between RSL sites and fault related morphology, including linear features and offsets, transtensional features, sub parallel zones, and multiple styles of brittle deformation. This detailed, systematic study characterizing the geologic context of all confirmed RSL sites as well as of observed locations that present a setting favorable to RSL but without the presence of RSL, further explores this correlation, constraining plausible RSL formation mechanisms.

Watkins, J.; Ojha, L.; Reith, R. C.; Yin, A.

2013-12-01

74

Formation of share market prices under heterogeneous beliefs and common knowledge  

NASA Astrophysics Data System (ADS)

Financial economic models often assume that investors know (or agree on) the fundamental value of the shares of the firm, easing the passage from the individual to the collective dimension of the financial system generated by the Share Exchange over time. Our model relaxes that heroic assumption of one unique “true value” and deals with the formation of share market prices through the dynamic formation of individual and social opinions (or beliefs) based upon a fundamental signal of economic performance and position of the firm, the forecast revision by heterogeneous individual investors, and their social mood or sentiment about the ongoing state of the market pricing process. Market clearing price formation is then featured by individual and group dynamics that make its collective dimension irreducible to its individual level. This dynamic holistic approach can be applied to better understand the market exuberance generated by the Share Exchange over time.

Biondi, Yuri; Giannoccolo, Pierpaolo; Galam, Serge

2012-11-01

75

Geoenvironmental evaluation of geological formations of Lithuania for radioactive waste disposal  

SciTech Connect

The Ignalina Nuclear Power Plant, operating at present in Lithuania, every year produces approximately 1,5 ths.t. of radioactive wastes. They are being stored in temporary areas. The possibilities of underground disposal of radioactive wastes were evaluated. There are three geological formations in Lithuania, which are potentially suitable media for radioactive wastes disposal: Lower proterozoic rocks of crystalline basement, Upper Permian anhydrite layer, and Upper Permian salt domes. They are being proposed in the radioactive wastes management program as candidates for more detail investigations.

Kadunas, V.; Valiunas, J. [Institute of Geology, Vilnius (Lithuania)

1996-12-01

76

Stochastic analysis of pumping test drawdown data in heterogeneous geologic formations  

Microsoft Academic Search

Pumping tests are often used to estimate effective values of the transmissivity and the storativity of the perturbed aquifer portion surrounding the pumping well and observation points. The interpretation of such pumping tests is based on analytic or semi-analytic methods that are normally developed under the assumption of homogeneity in the vicinity of the well. The purpose of this paper

Nadim K. Copty; Angelos N. Findikakis

2004-01-01

77

Role of geomechanically grown fractures on dispersive transport in heterogeneous geological formations.  

PubMed

A second order in space accurate implicit scheme for time-dependent advection-dispersion equations and a discrete fracture propagation model are employed to model solute transport in porous media. We study the impact of the fractures on mass transport and dispersion. To model flow and transport, pressure and transport equations are integrated using a finite-element, node-centered finite-volume approach. Fracture geometries are incrementally developed from a random distributions of material flaws using an adoptive geomechanical finite-element model that also produces fracture aperture distributions. This quasistatic propagation assumes a linear elastic rock matrix, and crack propagation is governed by a subcritical crack growth failure criterion. Fracture propagation, intersection, and closure are handled geometrically. The flow and transport simulations are separately conducted for a range of fracture densities that are generated by the geomechanical finite-element model. These computations show that the most influential parameters for solute transport in fractured porous media are as follows: fracture density and fracture-matrix flux ratio that is influenced by matrix permeability. Using an equivalent fracture aperture size, computed on the basis of equivalent permeability of the system, we also obtain an acceptable prediction of the macrodispersion of poorly interconnected fracture networks. The results hold for fractures at relatively low density. PMID:22181492

Nick, H M; Paluszny, A; Blunt, M J; Matthai, S K

2011-11-01

78

On the accuracy of classic numerical schemes for modeling flow in saturated heterogeneous formations  

NASA Astrophysics Data System (ADS)

Quantitative hydrogeology often relies on numerical modeling of flow and transport processes in the earth subsurface. Despite the richness of numerical schemes proposed in the literature most applications are performed by using a few very popular codes based on classical finite volume or finite element techniques. An important limitation of these numerical schemes is that they lead to solutions that do not satisfy the refraction law of streamlines at element (or volume) edges. This is not of great concern when the hydraulic conductivity K is spatially homogeneous, or varies smoothly within the computational domain. However, the solution may deteriorate in heterogeneous formations with high contrast between the hydraulic conductivity of adjacent computational cells. We analyze the performance of four widely used classic numerical schemes for solving the flow equation when they are applied to heterogeneous porous media. We first analyze the convergence of the numerical schemes to a known analytical solution in a simple heterogeneous field composed by 4 blocks with contrasting hydraulic conductivities. Then we compare the numerical solutions obtained in both Gaussian and exponential weakly heterogeneous logconductivity fields with existing analytical first- and second-order solutions in the variance of the logconductivity field, ?Y2. Our analysis highlights that postprocessing the velocity field to enforce a posteriori the refraction law leads to biased results and that the performance of the numerical scheme depends on how mass conservation is discretized on the computational grid. Numerical schemes using inter-block conductivities, based for example on the harmonic mean, modify the spatial structure of the conductivity, with a negative impact on the structure of the velocity field.

Cainelli, Oscar; Bellin, Alberto; Putti, Mario

2012-10-01

79

Geologic setting, petrophysical characteristics, and regional heterogeneity patterns of the Smackover in southwest Alabama. Draft topical report on Subtasks 2 and 3  

SciTech Connect

This is the draft topical report on Subtasks 2 and 3 of DOE contract number DE-FG22-89BC14425, entitled ``Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity.`` This volume constitutes the final report on Subtask 3, which had as its primary goal the geological modeling of reservoir heterogeneity in Smackover reservoirs of southwest Alabama. This goal was interpreted to include a thorough analysis of Smackover reservoirs, which was required for an understanding of Smackover reservoir heterogeneity. This report is divided into six sections (including this brief introduction). Section two, entitled ``Geologic setting,`` presents a concise summary of Jurassic paleogeography, structural setting, and stratigraphy in southwest Alabama. This section also includes a brief review of sedimentologic characteristics and stratigraphic framework of the Smackover, and a summary of the diagenetic processes that strongly affected Smackover reservoirs in Alabama. Section three, entitled ``Analytical methods,`` summarizes all nonroutine aspects of the analytical procedures used in this project. The major topics are thin-section description, analysis of commercial porosity and permeability data, capillary-pressure analysis, and field characterization. ``Smackover reservoir characteristics`` are described in section four, which begins with a general summary of the petrographic characteristics of porous and permeable Smackover strata. This is followed by a more-detailed petrophysical description of Smackover reservoirs.

Kopaska-Merkel, D.C.; Mann, S.D.; Tew, B.H.

1992-06-01

80

Geologic and hydrogeologic characteristics of the Ogallala Formation and White River Group, Belvoir Ranch near Cheyenne, Laramie County, Wyoming  

USGS Publications Warehouse

The geologic and hydrogeologic characteristics of Tertiary lithostratigraphic units (Ogallala Formation and White River Group) that typically compose or underlie the High Plains aquifer system in southeastern Wyoming were described physically and chemically, and evaluated at a location on the Belvoir Ranch in Laramie County, Wyoming. On the basis of this characterization and evaluation, three Tertiary lithostratigraphic units were identified using physical and chemical characteristics determined during this study and previous studies, and these three units were determined to be correlative with three identified hydrogeologic units composing the groundwater system at the study site—a high-yielding aquifer composed of the entire saturated thickness of the heterogeneous and coarse-grained fluvial sediments assigned to the Ogallala Formation (Ogallala aquifer); an underlying confining unit composed primarily of very fine-grained volcaniclastic sediments and mudrocks assigned to the Brule Formation of the White River Group and some additional underlying sediments that belong to either the Brule or Chadron Formation, or both (Brule confining unit); and an underlying low-yielding aquifer composed primarily of poorly sorted fluvial sediments assigned to the Chadron Formation of the White River Group (Chadron aquifer). Despite widely varying sediment heterogeneity and consolidation, some limited hydraulic connection throughout the full vertical extent of the Ogallala aquifer was indicated but not conclusively proven by interpretation of similar chemical and isotopic characteristics, modern apparent groundwater ages, and similar hydraulic-head responses measured continuously in two Ogallala aquifer monitoring wells installed for this study at two different widely separated (83 feet) depth intervals. Additional work beyond the scope of this study, such as aquifer tests, would be required to conclusively determine hydraulic connection within the Ogallala aquifer. Groundwater levels (hydraulic heads) measured continuously using water-level recorders in both monitoring wells completed in the Ogallala aquifer showed a consistent strong upward vertical gradient in the Ogallala aquifer, indicating the potential for water to move from deeper to shallower parts of the aquifer, regardless of the time of year and the presumed effects of pumping of public-supply and industrial wells in the area. Continuous measurement of groundwater levels in the shallowest monitoring well, installed near the water table, and examination of subsequently constructed water-level hydrographs indicated substantial groundwater recharge is likely during the spring of 2009 and 2010 from the ephemeral stream (Lone Tree Creek) located adjacent to the study site that flows primarily in response to spring snowmelt from the adjacent Laramie Mountains and surface runoff from precipitation events. Using the water-table fluctuation method, groundwater recharge was estimated to be about 13 inches for the period beginning in early October 2009 and ending in late June 2010, and about 4 inches for the period beginning in March 2011 and ending in early July 2011. Comparison of previously measured groundwater levels (hydraulic heads) and groundwater-quality characteristics in nearby monitoring wells completed in the Chadron aquifer with those measured in the two monitoring wells installed for this study in the Ogallala aquifer, combined with detailed lithologic characterization, strongly indicated the Brule confining unit hydraulically confines and isolates the Chadron aquifer from the overlying Ogallala aquifer, thus likely limiting hydraulic connection between the two units. Consequently, because of the impermeable nature of the Brule confining unit and resulting hydraulic separation of the Ogallala and Chadron aquifers, and compared with local and regional hydrostratigraphic definitions of the High Plains aquifer system, the groundwater system in Tertiary lithostratigraphic units overlying the Upper Cretaceous Lance Formation at the location studied on the Belvoir Ranch was

Bartos, Timothy T.; Diehl, Sharon F.; Hallberg, Laura L.; Webster, Daniel M.

2014-01-01

81

Characterization of geological formations by physical parameters obtained through full waveform acoustic logging  

NASA Astrophysics Data System (ADS)

In this paper, we will show through a field example that full wave form acoustic logging allows a quantitative evaluation of geological formations. For that purpose, conventional logs and their associated standard deviation (Std) must be computed (formation velocities, amplitudes, frequencies, etc.) since the Std is used to estimate the uncertainties associated with the log and to edit other logs. The missing values are then reconstructed by geostatistical interpolation (ordinary kriging and co-kriging). The shear velocity and density of the formation are also estimated in order to obtain mechanical parameters such as Poisson’s ratio or shear modulus. Since the converted refracted shear waves can be recorded in fast formations, a joint method based on the local measurement of the shear velocity by picking the arrival times of the refracted S wave and interpolation by co-kriging with P-wave velocity log has been used to compute a continuous shear velocity log. The Analysis of the dispersive properties of the Stoneley modes has then been used to estimate density variations and build iteratively a density log from an a priori density model. Furthermore, we will show that a dimensionless shape index can be used as a qualitative acoustic attribute to detect the presence of interfering waves, anomalic zones and to obtain a measurement of the attenuation. We will also show that P-wave attenuation , P-wave frequency and acoustic porosity logs can be fruitfully used to compute an acoustic permeability log.

Mari, J. L.; Gaudiani, P.; Delay, J.

82

BIGFLOW: A numerical code for simulating flow in variably saturated, heterogeneous geologic media. Theory and user`s manaual, Version 1.1  

SciTech Connect

This report documents BIGFLOW 1.1, a numerical code for simulating flow in variably saturated heterogeneous geologic media. It contains the underlying mathematical and numerical models, test problems, benchmarks, and applications of the BIGFLOW code. The BIGFLOW software package is composed of a simulation and an interactive data processing code (DATAFLOW). The simulation code solves linear and nonlinear porous media flow equations based on Darcy`s law, appropriately generalized to account for 3D, deterministic, or random heterogeneity. A modified Picard Scheme is used for linearizing unsaturated flow equations, and preconditioned iterative methods are used for solving the resulting matrix systems. The data processor (DATAFLOW) allows interactive data entry, manipulation, and analysis of 3D datasets. The report contains analyses of computational performance carried out using Cray-2 and Cray-Y/MP8 supercomputers. Benchmark tests include comparisons with other independently developed codes, such as PORFLOW and CMVSFS, and with analytical or semi-analytical solutions.

Ababou, R. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Bagtzoglou, A.C. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

1993-06-01

83

Mantle heterogeneity under spreading zones of polar regions of the Atlantic Ocean: sources and formation  

NASA Astrophysics Data System (ADS)

A number of provinces with prevailing distribution of enriched rift basalts are specified within spreading zones of Indo-Atlantic segment of the World Ocean. The main reason of EMORB-type melts formation is determined by source heterogeneity which is resulted in numerous causes: recycling of old oceanic crust, hotspots within immediate proximity to rift zone, formation of metasomtizated mantle at the early stage of ocean opening which is involved in melting process later on. The spatial distribution of enriched tholeiites within Polar Atlantic is confined by Knipovich, Kolbeinsey and Gakkel ridges. The Knipovich ridge spreading zone formation coincides in time with magmatism appearances in adjacent continental regions. Comparative studying of Neogene and Quaternary magmatism of the Svalbard Island and modern magmatism of the Knipovich ridge reveals pyroxenite mantle participation in the melting process. The main source for Neogene magmas of the Svalbard Island was olivine-free pyroxenite with high 87Sr/86Sr and lower 143Nd/144Nd ratios, which could be a result of interaction of recycled substance of old oceanic crust and low continental crust with mantle peridotite. Due to its preferential fusibility this pyroxenite could be the source for substantial magmas volume under the rigid continental lithosphere that subsequently could have caused its disintegration. With successive rejuvenation of Svaldbard and Knipovich ridge magmatism (from Neogene till nowadays) for its mantle sources there has been traced the decreasing of pyroxenite component share at the expense of increasing of peridotite share accompanied by regular change of Sr and Nd isotope composition of these sources. The old Antarctic continent played a pivot role in the South Ocean formation, geodynamics and magmatism of trap formations and rift zones. The area of Karoo-Maud plume distribution at the early stages (about 180 - 170 Ma) included the southeastern part of Africa and the west of East Antarctic and nowadays it occupies the area of Bouvet hotspot modern location. Development of Karoo-Maud plume caused the formation of considerable mantle heterogeneity and contributed to disintegration of continental blocks within the forming South Ocean. Magmatism of the formed spreading basins of the western Antarctic (Powell and Bransfield) is characterized by greater range of enrichment and evidence to possible melting of pyroxenites which represented the fragments of low parts of continental lithosphere involved into the melting process at mantle asthenospheric upwelling in spreading zones. This component is close by its isotope characteristics to a component revealed within the western edge of Southwest Indian Ridge near the Bouvet triple junction and is represented by a mixture of sources like HIMU and EM-2.

Sushchevskaya, N. M.; Belyatsky, B. V.; Dubinin, E. P.

2012-04-01

84

Atmospheric Secondary Aerosol Formation by Heterogeneous Reactions of Aldehydes in the Presence of a Sulfuric Acid Aerosol Catalyst  

NASA Astrophysics Data System (ADS)

Particle growth by the heterogeneous reaction of aldehydes was observed in 0.5 m3 indoor Teflon bags in the presence of background seed aerosols. The aldehydes used were: glyoxal, butanal, hexanal, octanal, and decanal. To study acid catalyst effects on aldehyde heterogeneous reactions, one of the Teflon bags was initially filled with seed aerosols composed of ammonium sulfate-aerosol acidified with sulfuric acid. This result was compared to particle growth reactions that contained only ammonium sulfate as a background seed aerosol. The gas phase aldehydes were then added to the Teflon bags. In selected experiments, 1-decanol was also added to the Teflon bags with aldehydes to clarify particle growth via a heterogeneous hemiacetal/acetal formation in the presence/absence of an acid catalyst. The particle size distribution and growth were measured using a differential mobility analyzer (DMA), and the results were applied to predicting aerosol growth and size distribution changes by condensation and heterogeneous reactions. Aerosols created from the heterogeneous reactions of aldehydes were collected directly on an ungreased zinc selenide (ZnSe) FTIR disk (25 mm in diameter) by impaction. The ZnSe disks were directly analyzed for product functional groups in the aerosol phase using a Fourier transform infrared (FTIR) spectrometer with a deuterated triglycine sulfate (DTGS) detector. Aerosol growth by heterogeneous aldehyde reactions proceeds via a hydration, polymerization process, hemiacetal/acetal formation from the reaction of aldehydes with alcohols. These aldehyde heterogeneous reactions were accelerated in the presence of an acid catalyst, H2SO4, and led to higher aerosol yields than when H2SO4 was not present in the seed aerosol. The FTIR spectra obtained from the growing aerosol, also illustrated aldehyde group transformation in the particle phase as a function of the heterogeneous reaction. It was concluded that aldehydes, which can be produced by atmospheric photochemical reactions, can significantly contribute on secondary aerosol formation through heterogeneous reactions in the presence of an acid catalyst.

Jang, M.; Kamens, R. M.

2001-12-01

85

Travel time approach to kinetically sorbing solute by diverging radial flows through heterogeneous porous formations  

NASA Astrophysics Data System (ADS)

Diverging radial flow takes place in a heterogeneous porous medium where the log conductivity Y = ln K is modeled as a stationary random space function (RSF). The flow is steady, and is generated by a fully penetrating well. A linearly sorbing solute is injected through the well envelope, and we aim at computing the average flux concentration (breakthrough curve). A relatively simple solution for this difficult problem is achieved by adopting, similar to Indelman and Dagan (1999), a few simplifying assumptions: (i) a thick aquifer of large horizontal extent, (ii) mildly heterogeneous medium, (iii) strongly anisotropic formation, and (iv) large Peclet number. By introducing an appropriate Lagrangian framework, three-dimensional transport is mapped onto a one-dimensional domain (?, t) where ? and t represent the fluid travel and current time, respectively. Central for this approach is the probability density function of the RSF ?that is derived consistently with the adopted assumptions stated above. Based on this, it is shown that the travel time can be regarded as a Gaussian random variable only in the far field. The breakthrough curves are analyzed to assess the impact of the hydraulic as well as reactive parameters. Finally, the travel time approach is tested against a forced-gradient transport experiment and shows good agreement.

Severino, Gerardo; de Bartolo, Samuele; Toraldo, Gerardo; Srinivasan, Gowri; Viswanathan, Hari

2012-12-01

86

Formation evaluation and geological interpretation from the resistivity-at-the-bit tool  

SciTech Connect

The RAB (Resistivity-at-the-Bit) tool is a logging-while-drilling device designed to accurately measure resistivity in salty muds and high resistivity formations such as carbonates. Included among the RAB`s measurements are three azimuthally oriented buttons that provide focused resistivity images with shallow, medium and deep depths of investigation. Combinations of these measurements with a focused ring electrode can be used to determine Rt in the presence of invasion. RAB data can also be combined with other LWD measurements to obtain high quality formation evaluation. The RAB tool is unique among LWD tools in its ability to acquire fullbore formation images. Such images not only provide quantitative resistivity, but also give information on the structural geology and depositional environment. Bedding dips computed from the RAB tool compare well with those from wireline image logs. Large scale structural features (bedding, faults, etc.) are readily interpreted from RAB images and dips. As with dip interpretation from other image logs, best results are obtained when images are used to evaluate structural interpretation from batch-processed RAB dips. To help operators more fully utilize RAB data in time-critical drilling situations, a technique is proposed to compute high-angle apparent dips in real-time. Such a capability will be particularly useful for geosteering near-horizontal wells.

Rosthal, R.A.; Lovell, J.R.; Arceneaux, C.L. Jr. [and others

1995-12-31

87

Conformational heterogeneity in antibody-protein antigen recognition: implications for high affinity protein complex formation.  

PubMed

Specific, high affinity protein-protein interactions lie at the heart of many essential biological processes, including the recognition of an apparently limitless range of foreign proteins by natural antibodies, which has been exploited to develop therapeutic antibodies. To mediate biological processes, high affinity protein complexes need to form on appropriate, relatively rapid timescales, which presents a challenge for the productive engagement of complexes with large and complex contact surfaces (?600-1800 ?(2)). We have obtained comprehensive backbone NMR assignments for two distinct, high affinity antibody fragments (single chain variable and antigen-binding (Fab) fragments), which recognize the structurally diverse cytokines interleukin-1? (IL-1?, ?-sheet) and interleukin-6 (IL-6, ?-helical). NMR studies have revealed that the hearts of the antigen binding sites in both free anti-IL-1? Fab and anti-IL-6 single chain variable exist in multiple conformations, which interconvert on a timescale comparable with the rates of antibody-antigen complex formation. In addition, we have identified a conserved antigen binding-induced change in the orientation of the two variable domains. The observed conformational heterogeneity and slow dynamics at protein antigen binding sites appears to be a conserved feature of many high affinity protein-protein interfaces structurally characterized by NMR, suggesting an essential role in protein complex formation. We propose that this behavior may reflect a soft capture, protein-protein docking mechanism, facilitating formation of high affinity protein complexes on a timescale consistent with biological processes. PMID:24436329

Addis, Philip W; Hall, Catherine J; Bruton, Shaun; Veverka, Vaclav; Wilkinson, Ian C; Muskett, Frederick W; Renshaw, Philip S; Prosser, Christine E; Carrington, Bruce; Lawson, Alastair D G; Griffin, Robert; Taylor, Richard J; Waters, Lorna C; Henry, Alistair J; Carr, Mark D

2014-03-01

88

Domain formation in membranes with quenched protein obstacles: Lateral heterogeneity and the connection to universality classes  

NASA Astrophysics Data System (ADS)

We show that lateral fluidity in membranes containing quenched protein obstacles belongs to the universality class of the two-dimensional random-field Ising model. The main feature of this class is the absence of a phase transition: there is no critical point and macroscopic domain formation does not occur. Instead there is only one phase. This phase is highly heterogeneous with a structure consisting of microdomains. The presence of quenched protein obstacles thus provides a mechanism to stabilize lipid rafts in equilibrium. Crucial for two-dimensional random-field Ising universality is that the obstacles are randomly distributed and have a preferred affinity to one of the lipid species. When these conditions are not met standard Ising or diluted Ising universality applies. In these cases a critical point does exist which then marks the onset toward macroscopic demixing.

Fischer, T.; Vink, R. L. C.

2011-02-01

89

Geologic and hydrologic controls on the movement of water through a thick, heterogeneous unsaturated zone underlying an intermittent stream in the western Mojave Desert, southern California  

NASA Astrophysics Data System (ADS)

A two-dimensional, axially symmetric, unsaturated flow model was developed to test hypotheses about geologic and hydrologic controls on the movement of water through the thick, heterogeneous, unsaturated zone underlying Oro Grande Wash in the Mojave Desert, California. Heterogeneity within the unsaturated zone was simulated with multiple realizations of subsurface geology estimated on the basis of transition probability/Markov chain statistics. Model results show lateral spreading of water away from the wash was best approximated by realizations that include thin, horizontally extensive clay layers that impede the downward movement of water. There was a wide range in model responses for these realizations, and the movement of water through unsaturated zones containing thin, horizontally extensive clay layers may be more difficult to predict than water movement through unsaturated zones where clay layers are less extensive. For realizations having less extensive clay layers, the range of model responses decreased with time, and model results became increasingly similar as water encountered larger volumes of material.

Izbicki, John A.

2002-03-01

90

Modeling Biogeochemistry and Flow within Heterogeneous Formations in Variably-Saturated Media  

E-print Network

heterogeneity on coupled biogeochemical processes across column and landfill scales. Structural heterogeneity in the form of macropore distributions (no macropore, single macropore, and multiple macropores) in experimental soil columns is investigated...

Arora, Bhavna

2012-10-19

91

Kinetics of the heterogeneously catalyzed formation of tert-amyl ethyl ether  

SciTech Connect

In this work, the kinetics and equilibrium of the heterogeneously catalyzed liquid-phase formation of tert-amyl ethyl ether (TAEE) were studied. The catalyst used was a commercial sulfonic acid ion-exchange resin (Amberlyst 16W). The experiments were carried out in a continuous stirred-tank reactor, measuring stationary reaction rates. The measured reaction rates were fitted to three kinetic models; homogeneous, Eley-Rideal type, and Langmuir-Hinshelwood type. Of these, the Langmuir-Hinshelwood type model described the experimental results best. This model is based on single-site adsorption of every component, with the surface reaction being the rate-limiting step. The activation energies for the formation of tert-amyl ethyl ether from 2-methyl-1-butene were 90 and from 2-methyl-2-butene 108 kJ/mol. For the isomerization of 2-methyl-1-butene to 2-methyl-2-butene, an activation energy of 82 kJ/mol was obtained.

Linnekoski, J.A.; Krause, A.O. [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Industrial Chemistry] [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Industrial Chemistry; Rihko, L.K. [Neste Oy, Porvoo (Finland). Technology Center] [Neste Oy, Porvoo (Finland). Technology Center

1997-02-01

92

Influence of Mineral Dust On New Particle Formation and Growth: A Model Study of Heterogeneous Nucleation  

NASA Astrophysics Data System (ADS)

Analyses of nucleation events have emphasized the importance of pre-existing par- ticles in new particle formation. When coarse mode aerosol is present, it typically dominates the condensation sink for trace gases and thus inhibits the onset of nucle- ation. A monodisperse aerosol dynamical box model is applied to investigate the effect of soluble coated mineral dust particles on new particle formation. The model in- cludes ternary H2SO4­H2O­NH3 nucleation, multicomponent condensation, coagu- lation and dry deposition. As the soluble coating can significantly change the ability of dust particles to serve as a condensation sink for condensable vapours, different mech- anisms of coating, including heterogeneous nucleation of sulphuric acid, are consid- ered. Preliminary results show that the presence of micron sized soluble coated dust par- ticles can even at relatively low concentrations prevent homogeneous nucleation or growth of nucleated particles to detectable size of 3 nm. Furthermore, critical conden- sation sinks obtained by model simulations correspond to measured sinks.

Korhonen, H.; Kulmala, M.; Lauri, A.

93

Geologic control of jet formation on Comet 103P/Hartley 2  

NASA Astrophysics Data System (ADS)

The EPOXI mission flyby of Comet 103P/Hartley 2 revealed numerous discrete dust jets extending from the nucleus, thereby providing an unprecedented opportunity to visually connect these features to the nuclear surface. The observed distribution of jets yields fresh insight into the conditions under which these cometary features may form. This study examines the geomorphology associated with areas of jet activity and then applies observed topographic correlations in the construction of a 2-D hydrodynamic model of a single dust jet. Visible light images of Hartley 2 show correlations between specific surface structures with both narrow-angle and fan-shaped dust jets; associations include pits, arcuate depressions, scarps, and rimless depressions. Notably, many source regions for jets appear finer than the practical mapping resolution of the imaging instruments (˜12 m). This observation indicates that the processes controlling jet formation operate at significantly finer scales than the resolution of most cometary activity models and motivates a complementary numerical investigation of dust jet formation and evolution. In order to assess controlling variables, our parametric numerical study incorporates different geometries and volatile abundances for the observed source regions. Results indicate that the expression of jet activity not only depends on local topography but also contributes to the evolution and development of surface features. Heterogeneous distributions of volatiles within the nucleus also may contribute to differences in local styles of jet activity.

Bruck Syal, Megan; Schultz, Peter H.; Sunshine, Jessica M.; A'Hearn, Michael F.; Farnham, Tony L.; Dearborn, David S. P.

2013-02-01

94

Assessment of potential radionuclide transport in site-specific geologic formations  

SciTech Connect

Associated with the development of deep, geologic repositories for nuclear waste isolation is a need for safety assessments of the potential for nuclide migration. Frequently used in estimating migration rates is a parameter generally known as a distribution coefficient, K/sub d/, which describes the distribution of a radionuclide between a solid (rock) and a liquid (groundwater) phase. This report is intended to emphasize that the use of K/sub d/ must be coupled with a knowledge of the geology and release scenarios applicable to a repository. Selected K/sub d/ values involving rock samples from groundwater/brine simulants typical of two potential repository sites, WIPP and NTS, are used to illustrate this concern. Experimental parameters used in K/sub d/ measurements including nuclide concentration, site sampling/rock composition, and liquid-to-solid ratios are discussed. The solubility of U(VI) in WIPP brine/groundwater was addressed in order to assess the potential contribution of this phenomena to K/sub d/ values. Understanding mehanisms of sorption of radionuclides on rocks would lead to a better predictive capability. Sorption is attributed to the presence of trace constituents (often unidentified) in rocks. An attempt was made to determine if this applied to WIPP dolomite rocks by comparing sorption behavior of the natural material with that of a synthetic dolomite prepared in the laboratory with reagent grade chemicals. The results were inconclusive. The results of a study of Tc sorption by an argillite sample from the Calico Hills formation at NTS under ambient laboratory conditions were more conclusive. The Tc sorption was found to be associated with elemental carbon. Available evidence points to a reduction mechanism leading to the apparent sorption of Tc on the solid phase.

Dosch, R.G.

1980-08-01

95

Development of a novel heterogeneous flow reactor -- Soot formation and nanoparticle catalysis  

NASA Astrophysics Data System (ADS)

The development of novel experimental approaches to investigate fundamental surface kinetics is presented. Specifically, fundamental soot formation and surface catalysis processes are examined in isolation from other competing processes. In terms of soot formation, two experimental techniques are presented: the Burner Stabilized Stagnation (BSS) flame configuration is extended to isolate the effect of the parent fuel structure on soot formation and the fundamental rate of surface oxidation for nascent soot is measured in a novel aerosol flow reactor. In terms of nanoparticles, the physical and chemical properties of freely suspended nanoparticles are investigated in a novel aerosol flow reactor for methane oxidation catalyzed by palladium. The role of parent fuel structure within soot formation is examined by following the time resolved formation nascent soot from the onset of nucleation to later growth stages for premixed BSS flames. Specifically, the evolution of the detailed particle size distribution function (PSDF) is compared for butanol, butane and C6 hydrocarbons in two separate studies where the C/O ratio and temperature are fixed. Under this constraint, the overall sooting process were comparable as evidenced by similar time resolved bimodal PSDF. However, the nucleation time and the persistence of nucleation with time is strongly dependent upon the structure of the parent fuel. For the C6 hydrocarbon fuels, the fastest onset of soot nucleation is observed in cyclohexane and benzene flames and this may be due to significant aromatic formation that is predicted in the pre-flame region. In addition, the evolution of the PSDF shows that nucleation ends sooner in cylclohexane and benzene flames and this may be due to relatively quick depletion of soot precursors such as acetylene and benzene. Interestingly,within the butanol fuels studied the effect of the branched chain in i-butanol and i-butane was more significant than the presence of fuel bound oxygen. A numerical analysis of the gas-phase chemistry for butanol and butane indicates the fuel structure effect is largely exhibited in the relative importance of C2 versus C3 intermediate species formed during the initial stage of fuel breakdown. Oxidation kinetics of soot are typically measured with carbon black or well aged soot as substrates. The soot surface is also assumed to be graphitic in theoretical soot oxidation rate calculations. However, recent experimental and theoretical studies show that nascent soot can have structures and surface composition drastically different from mature, graphitized soot. In the current study, oxidation of nascent soot by O2 was observed at T= 950 and 1000K for oxygen concentrations ranging from 1000 to 7800 ppm in a laminar aerosol flow reactor at ambient pressure. Oxidation behavior of primary particles (Dp < 20 nm) of nascent soot from a premixed BSS ethylene flame was observed by tracking the shift in the particle size distribution function (PSDF) under a given residence time. The measured rate of the surface reaction ranges from 1x106 -- 3x10 6 g/cm2s for nascent soot. The rate of oxidation observed at the given conditions is an order of magnitude faster than predicted by the classical Nagle Strickland-Constable (NSC) correlations derived from graphite oxidation. Heterogeneous surface reaction rates are highly sensitive to the surface composition. Thus the faster rate of surface reaction by the nascent soot observed currently suggests that the surface composition of nascent soot is more reactive than the conventional graphite surface. Catalytic activity in reacting flow laden with suspended nanoparticle catalyst is measured in a novel aerosol flow reactor. Similar to conventional gas phase kinetics, heterogeneous reactions are the product of collisions between the particle surface and surrounding gas. However, particles below 10 nm in diameter are in a transition region where collisions do not always result in perfectly elastic scattering. The inelastic scattering provides more opportunities for reaction to occur than

Camacho, Joaquin

96

Heterogeneity in a Low-Permeability Formation or Non-Ideal Testing Conditions?  

NASA Astrophysics Data System (ADS)

Hydraulic testing in packer-isolated wellbore intervals in low-permeability formations is often complicated by non-ideal conditions such as thermal expansion of fluid in the test interval, packer squeeze and borehole closure. Such processes lead to fluid accumulation and pressurization within the wellbore during shut-in, and can exert significant effects on the measured borehole pressure response. Unless these conditions are taken into account during test interpretation, it is possible to make inappropriate conclusions regarding formation heterogeneity (e.g., lateral permeability variations) and/or static pressure levels. We have developed a lumped parameter modeling approach by treating the combined effect of these processes as the equivalent of an additional volume of fluid accumulating within the test interval (in addition to the nominal test-interval volume at the time of shut-in). We postulate that the rate of fluid accumulation can be treated in a simple manner as a constant value for the duration of the test. Thus, the fluid accumulation problem can be recast as the equivalent of a constant injection rate into the packed-off volume within the borehole. We show how this surrogate injection rate can be estimated from the measured pressure data by exploiting the analogy between the pressure response during borehole storage dominated conditions and that of a line-source well with an exponentially varying flow rate. Shut-in test sequences (i.e., shut-in period prior to initiation of a pressure pulse test and shut-in period(s) during pulse test(s)) can then be analyzed as effective constant-rate injection periods. The methodology is demonstrated using data from a recent series of hydraulic tests conducted in support of site characterization activities by ANDRA, the French radioactive waste management agency. In many of these tests, the measured pressure response was fitted to a 2-zone radially composite system model. Although the fit was visually excellent, static pressure estimates were found to be significantly different than those obtained from long-term pressure monitoring data from permanently installed borehole pressure gauges that use wireless telemetry for data transmission. These special tools (called EPG tools) provide the highest quality monitoring data for defining true undisturbed formation pressures in very low-permeability formations. In this study, the hydraulic-test data were reanalyzed using the lumped parameter modeling approach with a single-zone homogeneous model constrained to the static pressure bounds indicated by the EPG data. The single-zone analysis yields visual fits comparable to those from the 2-zone radially composite model, and formation parameters that are statistically much more robust (i.e., they do not suffer from over-parameterization and poor parameter identifiability as do the parameter estimates from the 2-zone conceptualization). We conclude that the effects of non-ideal testing conditions can be mistaken as indicators of formational heterogeneities.

Mishra, S.; Deeds, N. E.; Pickens, J. F.; Distinguin, M.; Delay, J.

2005-12-01

97

3rd hand smoking; heterogeneous oxidation of nicotine and secondary aerosol formation in the indoor environment  

NASA Astrophysics Data System (ADS)

Tobacco smoking is well known as a significant source of primary indoor air pollutants. However, only recently has it been recognized that the impact of Tobacco smoking may continue even after the cigarette has been extinguished (i.e., third hand smoke) due to the effect of indoor surfaces. These surfaces may affect the fate of tobacco smoke in the form of secondary reactions and pollutants, including secondary organic aerosol (SOA) formation. Fourier Transform Infrared spectrometry with Attenuated Total Reflection (FTIR-ATR) in tandem with a Scanning Mobility Particle Sizing (SMPS) system was used to monitor the ozonation of cellulose sorbed nicotine and resulting SOA formation. SOA formation began at onset of ozone introduction ([O3] = 60 ± 5 ppb) with a size distribution of dp ? 25 nm, and was determined to be a result of heterogeneous reaction (opposed to homogeneous). SOA yield from reacted surface nicotine was on the order of 10 %. Simultaneous to SOA monitoring, FTIR-ATR spectra showed surface changes in the nicotine film as the reaction progressed, revealing a pseudo first-order surface reaction rate of 0.0026 ± 0.0008 min-1. Identified surface oxidation products included: cotinine, myosmine, methylnicotinamide and nicotyrine. Surface reaction rate was found to be partially inhibited at high relative humidity. Given the toxicity of some of the identified products (e.g., cotinine has shown potential mutagenicity and teratogenicity) and that small particles may contribute to adverse health effects, the present study indicates that exposure to 3rd hand smoke ozonation products may pose additional health risks.

Petrick, Lauren; Dubowski, Yael

2010-05-01

98

Spontaneous formation of heterogeneous patches on polymer-lipid core-shell particle surfaces during self-assembly.  

PubMed

Spontaneous formation of heterogeneous patches on the surface of lipid-based nanoparticles (NPs) and microparticles (MPs) due to the segregation of two different functional groups. Patch formation is observed when tracing the functional groups with quantum dots, gold nanoparticles, and fluorescent dyes. This discovery could have important implications for the future design of self-assembled NPs and MPs for different biomedical applications. PMID:23109494

Salvador-Morales, Carolina; Valencia, Pedro M; Gao, Weiwei; Karnik, Rohit; Farokhzad, Omid C

2013-02-25

99

Mercury's hollows: Constraints on formation and composition from analysis of geological setting and spectral reflectance  

NASA Astrophysics Data System (ADS)

unique to Mercury, hollows are shallow, flat-floored irregular depressions notable for their relatively high reflectance and characteristic color. Here we document the range of geological settings in which hollows occur. Most are associated with impact structures (simple bowl-shaped craters to multiring basins, and ranging from Kuiperian to Calorian in age). Hollows are found in the low-reflectance material global color unit and in low-reflectance blue plains, but they appear to be absent from high-reflectance red plains. Hollows may occur preferentially on equator- or hot-pole-facing slopes, implying that their formation is linked to solar heating. Evidence suggests that hollows form because of loss of volatile material. We describe hypotheses for the origin of the volatiles and for how such loss proceeds. Intense space weathering and solar heating are likely contributors to the loss of volatiles; contact heating by melts could promote the formation of hollows in some locations. Lunar Ina-type depressions differ from hollows on Mercury in a number of characteristics, so it is unclear if they represent a good analog. We also use MESSENGER multispectral images to characterize a variety of surfaces on Mercury, including hollows, within a framework defined by laboratory spectra for analog minerals and lunar samples. Data from MESSENGER's X-Ray Spectrometer indicate that the planet's surface contains up to 4% sulfur. We conclude that nanophase or microphase sulfide minerals could contribute to the low reflectance of the low-reflectance material relative to average surface material. Hollows may owe their relatively high reflectance to destruction of the darkening agent (sulfides), the presence of alteration minerals, and/or physical differences in particle size, texture, or scattering behavior.

Blewett, David T.; Vaughan, William M.; Xiao, Zhiyong; Chabot, Nancy L.; Denevi, Brett W.; Ernst, Carolyn M.; Helbert, JöRn; D'Amore, Mario; Maturilli, Alessandro; Head, James W.; Solomon, Sean C.

2013-05-01

100

Formation of heterogeneous magmatic series beneath North Santorini, South Aegean island arc  

NASA Astrophysics Data System (ADS)

The geochemistry of basaltic to dacitic lavas and dykes in the volcanic centres of North Santorini (Greece) has been investigated using elemental and Sr-Nd-Pb isotopic data and three main magmatic series with sub-parallel trace element patterns for basalts can be distinguished. The basalts have Sr and Nd isotopic values consistent with varying levels of incompatible-element mantle depletion. A fourth magma group with only two basalt samples has a trace element pattern with even lower contents of incompatible elements, especially Th, and with lower 87Sr/ 86Sr but higher 206Pb/ 204Pb. Heterogeneous magma formation beneath North Santorini throughout its 500 ka history is attributed to variable transfer of sedimentary components — either terrigenous or pelagic, as bulk sediments or high-temperature partial melts rather than fluids or low-temperature partial melts — from a rupture zone in the subducted slab to the overlying mantle. The three main magmatic series followed independent paths of assimilation of upper crustal materials during fractional crystallization. Assimilation was more pronounced at the basaltic stage. The long-lived histories of the three main magmatic series imply repetitive melting of isolated mantle regions, ascent of magmas through independent feeder systems, and their residence in separate crustal magma chambers.

Bailey, J. C.; Jensen, E. S.; Hansen, A.; Kann, A. D. J.; Kann, K.

2009-06-01

101

Source/Sink Matching for U.S. Ethanol Plants and Candidate Deep Geologic Carbon Dioxide Storage Formations  

SciTech Connect

This report presents data on the 140 existing and 74 planned ethanol production facilities and their proximity to candidate deep geologic storage formations. Half of the existing ethanol plants and 64% of the planned units sit directly atop a candidate geologic storage reservoir. While 70% of the existing and 97% of the planned units are within 100 miles of at least one candidate deep geologic storage reservoir. As a percent of the total CO2 emissions from these facilities, 92% of the exiting units CO2 and 97% of the planned units CO2 emissions are accounted for by facilities that are within 100 miles of at least one potential CO2 storage reservoir.

Dahowski, Robert T.; Dooley, James J.

2008-09-18

102

Microbial and Chemical Enhancement of In-Situ Carbon Mineralization in Geological Formation  

SciTech Connect

Predictions of global energy usage suggest a continued increase in carbon emissions and rising concentrations of CO{sub 2} in the atmosphere unless major changes are made to the way energy is produced and used. Various carbon capture and storage (CCS) technologies are currently being developed, but unfortunately little is known regarding the fundamental characteristics of CO{sub 2}-mineral reactions to allow a viable in-situ carbon mineralization that would provide the most permanent and safe storage of geologically-injected CO{sub 2}. The ultimate goal of this research project was to develop a microbial and chemical enhancement scheme for in-situ carbon mineralization in geologic formations in order to achieve long-term stability of injected CO{sub 2}. Thermodynamic and kinetic studies of CO{sub 2}-mineral-brine systems were systematically performed to develop the in-situ mineral carbonation process that utilizes organic acids produced by a microbial reactor. The major participants in the project are three faculty members and their graduate and undergraduate students at the School of Engineering and Applied Science and at the Lamont-Doherty Earth Observatory at Columbia University: Alissa Park in Earth and Environmental Engineering & Chemical Engineering (PI), Juerg Matter in Earth and Environmental Science (Co-PI), and Kartik Chandran in Earth and Environmental Engineering (Co-PI). Two graduate students, Huangjing Zhao and Edris Taher, were trained as a part of this project as well as a number of graduate students and undergraduate students who participated part-time. Edris Taher received his MS degree in 2012 and Huangjing Zhao will defend his PhD on Jan. 15th, 2014. The interdisciplinary training provided by this project was valuable to those students who are entering into the workforce in the United States. Furthermore, the findings from this study were and will be published in referred journals to disseminate the results. The list of the papers is given at the end of the report for reference.

Matter, J.; Chandran, K.

2013-05-31

103

Challenges in conditioning a stochastic geological model of a heterogeneous glacial aquifer to a comprehensive soft dataset  

NASA Astrophysics Data System (ADS)

In traditional hydrogeological investigations, one geological model is often used based on subjective interpretations and sparse data availability. This deterministic approach usually does not account for any uncertainties. Stochastic simulation methods address this problem and can capture the geological structure uncertainty. In this study the geostatistical software TProGS is utilized to simulate an ensemble of realizations for a binary (sand/clay) hydrofacies model in the Norsminde catchment, Denmark. TProGS can incorporate soft data, which represent the associated level of uncertainty. High density (20 m × 20 m × 2 m) airborne geophysical data (SkyTEM) and categorized borehole data are utilized to define the model of spatial variability and for soft conditioning the TProGS simulations. The category probabilities for the SkyTEM dataset are derived from a histogram probability matching method, where resistivity is paired with the corresponding lithology from the categorized borehole data. A novelty of this study is the incorporation of two distinct datasources into the stochastic modeling process that represents two extremes of the conditioning density spectrum; sparse borehole data and abundant SkyTEM data. The high density of spatially correlated SkyTEM data lead to very deterministic simulation results. This is caused by overconditioning and addressed by a work around utilizing a resampling (thinning) of the dataset. In the case of abundant conditioning data it is shown that TProGS is capable of reproducing non-stationary trends. The stochastic realizations are validated by five performance criteria: (1) sand proportion, (2) mean length, (3) geobody connectivity, (4) facies probability distribution and (5) facies probability - resistivity bias. As conclusion, a stochastically generated set of realizations soft conditioned to 200 m moving sampling of geophysical data performs most satisfying when balancing the five performance criteria and can be used in subsequent hydrogeological flow modeling to address the predictive uncertainty originated from the geological structure uncertainty.

Koch, J.; He, X.; Jensen, K. H.; Refsgaard, J. C.

2013-12-01

104

The Oil Game: Problem-based learning exercise in an Environmental Geology lecture-format class  

NSDL National Science Digital Library

This is an active engagement exercise as a capstone exercise in a unit on energy in an Environmental Geology class of non-science majors combining a 'field-based' simulation and 'office-based' geological modeling. It uses readily available supplies and easily constructed equipment that can take 1 or 2 class meetings.

Voorhees, David

105

FOREWORD: Heterogenous nucleation and microstructure formation---a scale- and system-bridging approach Heterogenous nucleation and microstructure formation---a scale- and system-bridging approach  

Microsoft Academic Search

Scope and aim of this volume. Nucleation and initial microstructure formation play an important role in almost all aspects of materials science [1-5]. The relevance of the prediction and control of nucleation and the subsequent microstructure formation is fully accepted across many areas of modern surface and materials science and technology. One reason is that a large range of material

H. Emmerich

2009-01-01

106

Effect of Upscaling on CO2 Storage and Leakage in Heterogeneous Formations  

NASA Astrophysics Data System (ADS)

In carbon sequestration in saline aquifers, CO2 displaces brine during injection and may continue to migrate by buoyancy after injection ends. During this migration, various modes of trapping occur: residual, dissolution, mineral, and local capillary trapping. The local capillary trapping takes place when a CO2 plume rising through an aquifer encounters a region where capillary entry pressure is locally larger than average, so CO2 accumulates beneath the region. This mode of trapping occurs in heterogeneous domains and can only be seen in fine-scale simulations that use heterogeneous capillary pressure field. Using homogeneous capillary pressure field or even several rock types in a heterogeneous domain fails to capture local capillary trapping. However, fine-scale simulation is always costly and often impractical, and an upscaling method would greatly facilitate assessment of large fields nominated for storage. The challenge, then, is for the coarse-scale model to capture the effect of fine-scale features on the distribution of CO2 and to give similar simulation results that are important from risk analysis point of view. Examples include whether the CO2 reaches the top seal of storage formation, the time it takes for CO2 to reach the top seal, and the amount of CO2 leakage if a presumptive leak develops in the top seal. The main difficulty in upscaling is for nonadditive properties, mainly permeability and multiphase flow properties. One of the important multiphase flow properties, especially in applications like CO2 storage where imbibition occurs, is residual saturation. It strongly affects the mass of CO2 that remains securely as residual phase in storage aquifer. It also affects the mass of escaped CO2 in the case of leakage from the aquifer through a breach in the overlying seal. Incorrect estimation of residual saturation in an upscaled model could lead to disqualification of a candidate aquifer due to wrong estimation of secure storage capacity or approval of a risky candidate aquifer. In this work, first we study the effect of upscaling based on single-phase properties on buoyancy-driven vertical flow of CO2. Porosity and absolute permeability are upscaled, then used to scale the end-point capillary pressures using Leverett scaling group. Relative permeabilities and reference capillary pressure curve are kept unchanged for upscaled model. Different degrees of coarsening are considered and results are analyzed based on average gas saturation and mass of CO2 in storage aquifer. Then, simulation of a leak at the top seal of the aquifer is upscaled, again with the single phase upscaling method, and the results are analyzed. Finally, using a corrected value of residual gas saturation in coarse-grid simulation is shown to give an acceptable result for the mass percent of escaped CO2. A correlation is derived between the upscaled or "effective residual saturation" and a measure of the variance in the permeability field. This method is validated using another synthetic field.

Saadatpoor, E.; Bryant, S. L.

2011-12-01

107

Integration of Sedimentology,Petrophysics and Statistics for Characterizing the Reservoir Heterogeneity of the Late Ordovician Sarah Formation, Central Saudi Arabia  

NASA Astrophysics Data System (ADS)

The first glaciogenic event in the Arabian Peninsula is represented by the Late Ordovician Sarah Formation. Sarah Formation is outcropping in areas of central and northern Arabia bordering the Arabian Shield, while it occupies several sub-basinal areas in the subsurface. The glacio-fluvial Sarah Formation is considered as an important tight gas reservoir target. This study uses the outcrop analog of the Sarah Formation to characterize the reservoir heterogeneity of the paleovalleys based on sedimentological, petrophysical, and statistical approaches. Facies types and architectural elements were identified within several paleovalleys of the Sarah Formation. The study indicated variability in texture, composition, sandstone type, facies, geometry and architecture at outcrop scale. Outcrop relationships also showed vertical and lateral facies change with other Paleozoic formations. The integration of field and laboratory data helped identifying the heterogeneity within Sarah paleovalleys. The reservoir quality trends in the Sarah Formation show variations that might be due to the controls of facies, depositional environments, and paleogeography. Three measures of heterogeneity were applied on the petrophysical data for various paleovalleys of the Sarah Formation. Those measures are: the coefficient of variation, Dykstra-Parsons, and Lorenz coefficients.The coefficient of variation values indicate extremely heterogeneous distribution. Dykstra-Parsons coefficient values suggest very to extremely heterogeneous reservoirs. Lorenz coefficients show good correlation with Dykstra-Parsons coefficient for Sarah paleovalleys. The studied heterogeneity measures indicate that Sarah paleovalleys represent very to extremely heterogeneous reservoirs.

El-Deek, Islam; Abdullatif, Osman; Korvin, Gabor; Al-Ramadan, Khalid

2014-05-01

108

The Carancas meteorite impact crater, Peru: Geologic surveying and modeling of crater formation and atmospheric passage  

NASA Astrophysics Data System (ADS)

The recent Carancas meteorite impact event caused a worldwide sensation. An H4-5 chondrite struck the Earth south of Lake Titicaca in Peru on September 15, 2007, and formed a crater 14.2 m across. It is the smallest, youngest, and one of two eye-witnessed impact crater events on Earth. The impact violated the hitherto existing view that stony meteorites below a size of 100 m undergo major disruption and deceleration during their passage through the atmosphere and are not capable of producing craters. Fragmentation occurs if the strength of the meteoroid is less than the aerodynamic stresses that occur in flight. The small fragments that result from a breakup rain down at terminal velocity and are not capable of producing impact craters. The Carancas cratering event, however, demonstrates that meter-sized stony meteoroids indeed can survive the atmospheric passage under specific circumstances. We present results of a detailed geologic survey of the crater and its ejecta. To constrain the possible range of impact parameters we carried out numerical models of crater formation with the iSALE hydrocode in two and three dimensions. Depending on the strength properties of the target, the impact energies range between approximately 100-1000 MJ (0.024- 0.24 t TNT). By modeling the atmospheric traverse we demonstrate that low cosmic velocities (12- 14 kms-1) and shallow entry angles (<20°) are prerequisites to keep aerodynamic stresses low (<10 MPa) and thus to prevent fragmentation of stony meteoroids with standard strength properties. This scenario results in a strong meteoroid deceleration, a deflection of the trajectory to a steeper impact angle (40-60°), and an impact velocity of 350-600 ms-1, which is insufficient to produce a shock wave and significant shock effects in target minerals. Aerodynamic and crater modeling are consistent with field data and our microscopic inspection. However, these data are in conflict with trajectories inferred from the analysis of infrasound signals.

Kenkmann, T.; Artemieva, N. A.; Wünnemann, K.; Poelchau, M. H.; Elbeshausen, D.; Núñez Del Prado, H.

2009-08-01

109

Capacity investigation of brine-bearing sands of the Fwwm formation for geologic sequestration of CO{sub 2}  

SciTech Connect

The capacity of fluvial brine-bearing formations to sequester CO{sub 2} is investigated using numerical simulations of CO{sub 2} injection and storage. Capacity is defined as the volume fraction of the subsurface available for CO{sub 2} storage and is conceptualized as a product of factors that account for two-phase flow and transport processes, formation geometry, formation heterogeneity, and formation porosity. The space and time domains used to define capacity must be chosen with care to obtain meaningful results, especially when comparing different authors' work. Physical factors that impact capacity include permeability anisotropy and relative permeability to CO{sub 2}, brine/CO{sub 2} density and viscosity ratios, the shape of the trapping structure, formation porosity and the presence of low-permeability layering.

Doughty, Christine; Pruess, Karsten; Benson, Sally M.; Hovorka, Susan D.; Knox, Paul R.; Green, Christopher T.

2001-05-01

110

Steady flow toward wells in heterogeneous formations: Mean head and equivalent conductivity  

NASA Astrophysics Data System (ADS)

We consider steady flow of water in a confined aquifer toward a fully penetrating well of radius rw (Figure 1). The hydraulic conductivity K is modeled as a three-dimensional stationary random space function. The two-point covariance of Y=ln(K/KG) is of axisymmetric anisotropy, with I and Iv, the horizontal and vertical integral scales, respectively, and KG, the geometric mean of K. Unlike previous studies which assumed constant flux, the well boundary condition is of given constant head (Figure 1). The aim of the study is to derive the mean head and the mean specific discharge as functions of the radial coordinate r and of the parameters ?2Y, e=Iv/I and rw/I. An approximate solution is obtained at first-order in ?2Y, by replacing the well by a line source of strength proportional to K and by assuming ergodicity, i.e., equivalence between H,q, space averages over the vertical, and ,, ensemble means. An equivalent conductivity Keq is defined as the fictitious one of a homogeneous aquifer which conveys the same discharge Q as the actual one, for the given head Hw in the well and a given head H in a piezometer at distance r from the well. This definition corresponds to the transmissivity determined in a pumping test by an observer that measures Hw, H, and Q. The main result of the study is the relationship (19) Keq=KA(1-?)+Kefu?, where KA is the conductivity arithmetic mean and Kefu is the effective conductivity for mean uniform flow in the horizontal direction in the same aquifer. The weight coefficient ?<1 is derived explicitly in terms of two quadratures and is a function of e, rw/I, and r/I. Hence Keq, unlike Kefu, is not a property of the medium solely. For rw/I<0.2 and for r/I>10, ? has the simple approximate expression ?*=ln(r/I)/ln(r/rw). Near the well, ??0 and Keq?KA, which is easily understood, since for rw/I<<1 the formation behaves locally like a stratified one. In contrast, far from the well ??1 and Keq?Kefu, the flow being slowly varying there. Since KA>Kefu, our result indicates that the transmissivity is overestimated in a pumping test in a steady state and it decreases with the distance from the well. However, the difference between KA and Kefu is small for highly anisotropic formations for which e<<1. A nonlocal effective conductivity, which depends only on the heterogeneous structure, is derived in Appendix A along the lines of Indelman and Abramovich [1994].

Indelman, P.; Fiori, A.; Dagan, G.

111

Effect of pattern formation on C and N turnover heterogeneity in initial soils  

NASA Astrophysics Data System (ADS)

The formation of vegetation patterns and hydrological processes, among others, result in soil heterogeneity in newly exposed land surfaces. We studied the effect of these developling structures on carbon and nitrogen trunover in soils of the artificial catchment Chicken Creek (Schaaf et al. 2011, 2012). Substrates with different physical and geochemical properties in combination with different labelled plant litter materials were studied in a microcosm experiment over a period of 80 weeks. Main objectives of the microcosm experiment were to determine the transformation processes of C and N from litter decomposition within the gaseous, liquid and solid phase, the interaction with mineral surfaces and its role for the establishment of biogeochemical cycles. The microcosm experiments were established in a climate chamber at constant 10 °C. In total, 48 soil columns (diameter: 14.4 cm; height: 30 cm) were filled with two different quaternary substrates (sand and loamy sand) representing the textural variation within the catchment at a bulk density of 1.4-1.5 g cm-3. The columns were automatically irrigated with artificial rainwater four times a day with 6.6 ml each (corresponding to 600 mm yr-1). The gaseous phase in the headspace of the microcosms was analyzed continuously for CO2 and N2O concentrations. C and N transformation processes were studied using 13C and 15N labelled litter of two different plant species occurring at the catchment (Lotus corniculatus, Calamagrostis epigejos) that was incorporated into the microcosm surface. By including litter from species with wide distribution within the catchment and soil substrates representing the main variation types of the sediments used for catchment construction we were able to characterize the general function of these sub-patches within the catchment with respect to litter decomposition, soil solution composition, DOC and nutrient leaching, and impact on the mineral soil phase. The results suggest that initial differences in substrate composition in combination with invading vegetation leads to the development of patterns with different biogeochemical process intensities within the catchment. These patterns are not mere additive effects of substrates plus litter, but reflect differences in element cycling. Schaaf, W., Bens, O., Fischer, A., Gerke, H.H., Gerwin, W., Grünewald, U., Holländer, H.M., Kögel-Knabner, I., Mutz, M., Schloter, M., Schulin, R., Veste, M., Winter, S. & Hüttl, R.F. (2011): Patterns and processes of initial terrestrial ecosystem development. J Plant Nutr Soil Sci, 174, 229-239. Schaaf, W., Elmer, M., Fischer, A., Gerwin, W., Nenov, R., Pretzsch, H., Seifert, S., Winter, S., Zaplata, M. (2012): Monitoring the formation of structures and patterns during initial development of an artificial catchment. Environmental Monitoring and Assessment. doi: 10.1007/s10661-012-2998-x.

Schaaf, Wolfgang; Zimmermann, Claudia

2013-04-01

112

Inefficient formation of ice via heterogeneous nucleation at temperatures below 200 K  

NASA Astrophysics Data System (ADS)

Nucleation of ice on aerosol particles is an important route to the formation of cirrus and other high altitude clouds in the atmosphere. Here we investigate heterogeneous ice nucleation via deposition mode freezing on both hydrophobic and hydrophilic surfaces using environmental molecular beam experiments and molecular dynamics simulations. We observe that nucleation of ice on a bare graphite crystal becomes increasingly inefficient as the surface temperature decreases from 200 to 155 K. The graphite has a hydrophobic character and water does not wet the surface efficiently in this temperature range. Adsorption of a monolayer of methanol on the graphite surface changes it from hydrophobic to highly hydrophilic. The methanol molecules provide sites for efficient hydrogen-bonding of water molecules, which stabilizes water on the surface compared to the bare graphite. Ice nucleation on the hydrophilic surface takes place at a lower supersaturation than on the hydrophobic surface, and the adsorbate thus influences the absolute nucleation rate at a given temperature. However, the supersaturation required for nucleation increases rapidly with decreasing temperature in the range 175-190 K, and the overall trend with temperature is similar for the bare and methanol-covered surface. Adsorption of a butanol monolayer results in an ice nucleation efficiency intermediate between the other systems. Butanol forms a highly stable solid layer on graphite. Water does not appear to wet the butanol layer efficiently and the water stability on the surface is lower than on the methanol layer. Again, the trend with temperature is similar to the other investigated systems. Thus, while the hydrophilicity of the different surfaces influences the absolute nucleation rate, the overall trend with temperature remains similar. The combination of the present investigations of carbon-based hydrophobic and hydrophilic systems with existing literature provides us with a sufficient data set to allow us to generalize the behavior of the deposition freezing process at low temperatures. Although the substrate plays a role, the overall trends with temperature are similar for different surfaces and therefore the explanation for the observed inefficient nucleation must be related to the inherent properties of water at low temperature. The importance of the results for cloud formation processes in the atmospheres on Earth and Mars are discussed.

Pettersson, J. B. C.; Kong, X.; Thomson, E. S.; M´, N.

2012-04-01

113

Laboratory investigations of the effects of geologic heterogeneity on groundwater salinization and flush-out times from a tsunami-like event  

NASA Astrophysics Data System (ADS)

This intermediate scale laboratory experimental study was designed to improve the conceptual understanding of aquifer flushing time associated with diffuse saltwater contamination of coastal aquifers due to a tsunami-like event. The motivation comes from field observations made after the tsunami in December, 2004 in South Asia. The focus is on the role and effects of heterogeneity on flushing effectiveness. A scheme that combines experimentation in a 4.8 m long laboratory tank and numerical modeling was used. To demonstrate the effects of geologic heterogeneity, plume migration and flushing times were analyzed in both homogeneous and layered media and under different boundary conditions (ambient flow, saltwater infiltration rate, freshwater recharge). Saltwater and freshwater infiltrations imitate the results of the groundwater salinization from the tsunami and freshening from the monsoon rainfall. The saltwater plume behavior was monitored both through visual observations (digital photography) of the dyed salt water and using measurements taken from several electrical conductivity sensors installed through the tank walls. The variable-density, three dimensional code HST3D was used to simulate the tank experiments and understand the fate and movement of the saltwater plume under field conditions. The results from the tank experiments and modeling demonstrated that macro-scale heterogeneity significantly influenced the migration patterns and flushing times of diffuse saltwater contamination. Ambient flow had a direct influence on total flush-out time, and heterogeneity impacted flush-out times for the top part of the tank and total flush-out times. The presence of a continuous low-permeability layer caused a 40% increase in complete flush-out time due to the slower flow of salt water in the low-permeability layer. When a relatively small opening was introduced in the low-permeability layer, salt water migrated quickly into a higher-permeable layer below causing a reduction in flush-out time. Freshwater recharge caused an early dilution of salt water in the top part of the tank in the case of a layered media, but also pushed the saltwater plume into the low-permeability layer which led to increased total flush-out times.

Vithanage, M.; Engesgaard, P.; Jensen, K. H.; Illangasekare, T. H.; Obeysekera, J.

2012-08-01

114

Aspherical structural heterogeneity within the uppermost inner core: Insights into the hemispherical boundaries and core formation  

E-print Network

of Petroleum, Beijing, China c Rice University, Department of Earth Science, Houston, TX, United States d and physical properties of this layer. Comparison of data from earthquakes with ray paths traversing from east to the west versus those with ray paths from west to east allow us to map the aspherical heterogeneity

Niu, Fenglin

115

Uncertainty aversion in a heterogeneous agent model of foreign exchange rate formation  

Microsoft Academic Search

This paper provides what we believe to be the first empirical test of whether investors in the foreign exchange market are uncertainty averse. We do this using a heterogeneous agents model in which fundamentalist and chartist beliefs of the exchange rate co-exist and are allowed to be either uncertainty neutral or uncertainty averse. Uncertainty aversion is modelled using the maxmin

Roman Kozhan; Mark Salmon

2009-01-01

116

DIGITAL CHROMATOGRAPHY AND THE FORMA-TION OF HETEROGENEOUS DROPLET LIBRARIES  

E-print Network

DIGITAL CHROMATOGRAPHY AND THE FORMA- TION OF HETEROGENEOUS DROPLET LIBRARIES USING of micro- droplet systems in high-throughput screening (HTS). This paper presents microfrac- tionation. (b) Droplet library formed in a 1.5 mm ID tube. this paper introduces microfractionation in droplets

Basu, Amar S.

117

Numerical Modeling of Smoke Formation in Smoldering Solid Fuels by Heterogeneous Condensation  

Microsoft Academic Search

This paper describes the results of an investigation that has been concerned with the development of a model capable of providing information for assessing the role of heterogeneous condensation in the production of smoke from smoldering solid fuels. The one-dimensional model presented in this paper considers the behavior of a porous fuel slab that is externally irradiated at one; of

K. KAILASANATH; B. T. ZINN

1983-01-01

118

Time-related capture zones for contaminants in randomly heterogeneous formations  

Microsoft Academic Search

Prediction of solute travel distance based on homogeneous and isotropic hydraulic conductivity may lead to substantial differences in the actual travel distance in a heterogeneous system. The effect of randomly varying hydraulic conductivity on the spatial location of time-related well capture zones for a nonreactive tracer in a confined aquifer with uniform base flow is considered. A numerical Monte Carlo

Alberto Guadagnini; Silvio Franzetti

1999-01-01

119

The Enigmatic Longevity of Granular Materials on Mars: The Case for Geologically Episodic Dune Formation  

NASA Technical Reports Server (NTRS)

Martian sand dunes are concentrated in vast sand seas in the circumpolar belt of the planet's northern hemisphere, but they are also pervasive over the whole planet. Their occurrence is to be expected on a super-arid planetary surface subjected to boundary layer drag from a continually active atmosphere. Whilst their occurrence is to be expected, their survival is enigmatic. But the enigma only arises if the martian system is considered similar to Earth's --where sand is moved highly frequently, more or less on a seasonal basis. Experimentally it is readily demonstrated that active sand will soon wear down to small grains and eventually diminish to below the critical sand size required to sustain dune formation. According to conventional wisdom, sand moves at higher speeds on Mars than on Earth, and if it were to move as frequently as it does on Earth, then the dune-forming sand population should have long since disappeared, given the great longevity of the martian aeolian system (Sagan coined the term "kamikaze" grains to express this disappearance). No supply of sand could keep pace with this depletion, especially in light of the fact that Mars does not have very active weathering, nor significant crustal differentiation. On Earth, plate tectonics, magmatic activity, and general crustal differentiation over geological time have produced great concentrations of quartz crystals in the continental crustal masses. Not only are these quartz grains chemically and mechanically resilient, they are about the right size for being transported by either wind or water. Add to this, the geologically recent contribution of glacial grinding, and it is easy to see why there are dune field on Earth. So what are the martian dunes composed of, and how does the material survive the eons of attrition? In addition to experimental demonstrations of sand comminution in laboratory aeolian simulations, the problem can be approached from first principles. Sagan showed that by simple considerations of material strength versus mechanical work applied to the material, comminution to sub-sand size would be inevitable. Another semi-analytical approach might be taken by considering that the archetypal aeolian sand surface texture is an irregularly pitted ("frosted") surface composed of chipping hollows approximately 10 microns in diameter, 5 microns deep. Their volume = about 250 cubic microns, or about 1/25000 of the volume of a 100 micron diameter dune grain. Because a saltating grain always strikes another grain, then two surfaces are impacted. Thus each grain undergoes two impacts for every one saltation leap, when the impact statistics are considered for a closed dune system (it can be calculated that a grain can never undergo <1 impact, and never >2 per saltation leap). Hence, if we conservatively assume that there is damage to a grain each time it bounces, but with the minimum damage of only 2 microscopic craters per impact, then approximately 12,500 impacts are required to completely eliminate the grain. Of course, it would require only a fraction of this amount to reduce the grain to below sand size. A grain will make only several tens of saltation leaps on the stoss side of a dune before becoming buried on the lee slope. The dune then has to move its full length before the grain is exhumed again for abrasion. Even with this hiatus in transport, it is easy to see that terrestrial dunes need resupplying with sand in order to survive. In recent theoretical work it has been shown that martian aeolian transport may be initiated with high-speed grains, but this converts to a lower energy dynamic transport equilibrium in which a reptation population dominates grain transport (on Earth, at least half of the flux is by reptation and creep). On Mars, therefore, average grain speeds may be lower than those on Earth, or at least comparable. This would permit greater longevity for martian sands, but it would not go far enough to solve the survival problem. It may, however, explain why martian dunes are about the same size as terr

Marshall, J.

1999-01-01

120

Geology of Wisconsin  

NSDL National Science Digital Library

This site contains geologic maps of Wisconsin including relief and topography maps; maps of the bedrock geology and elevation, Pleistocene geology, thickness of unconsolidated deposits, and soils; and atlases of geologic history. There is information on: rock types, Paleozoic formations, and the Pleistocene and Precambrian history of Wisconsin; how to obtain a geologic map of personal property; the Niagara Escarpment; castellated mounds; geologic field localities; and unusual weather events in Wisconsin. There is also a data table on earthquakes in Wisconsin.

Dutch, Steven

1997-09-10

121

The Effects of Heterogeneity on CO2 Gas Phase Evolution in the Shallow Subsurface During Leakage from Geologic Sequestration Sites: Intermediate Scale Experiments and Numerical Simulations  

NASA Astrophysics Data System (ADS)

A concern for geologic carbon sequestration is the potential for stored CO2 to leak upward into shallow freshwater aquifers where it can have potentially negative impacts. Understanding the mechanisms of CO2 migration and predicting its movement in shallow aquifers is a critical part of determining those potential impacts. During leakage, CO2 can move either as free-phase or as CO2 dissolved in brine. Dissolved CO2 may travel upward and/or migrate laterally through the subsurface, potentially causing the gas to come back out of solution (exsolve). Exsolved gas may become entrapped in the subsurface, and/or create flow paths that allow the gas to escape into the vadose zone and the atmosphere. The processes of gas exsolution, entrapment and flow in the shallow subsurface are controlled by various factors, including temperature, concentration of leaking CO2, pressure of the surrounding water, and heterogeneity of the subsurface environment. Unlike field studies, the laboratory setting allows for detailed observation of the relationships among these factors across multiple dimensionalities and scales. For this study, a series of one-dimensional laboratory experiments were conducted at an unprecedented spatial scale that yielded data with an unprecedented spatiotemporal resolution. Fresh water was saturated with dissolved CO2 gas under a specified pressure (the saturation pressure) before being injected at a constant volumetric flow rate into the bottom of a 4.5-meter tall column of sand that was initially saturated with fresh water. Soil moisture sensors installed along the length of the column detected the exsolution, growth, and entrapment of gas phase in the column through time by measuring the average water content in representative elementary volumes of soil. A gas flow meter and a scale continuously monitored the outflow of CO2 gas and water from the top of the column. Several packing configurations were used in order to test the effects of different types of heterogeneity on the evolution of the gas phase. Results indicate that: (1) heterogeneous interfaces trigger exsolution when they exist at a location where the water pressure is less than the saturation pressure, (2) in the short term, heterogeneity results in earlier gas exsolution, growth and flow while, in the long-term, it leads to local entrapment of gas phase (e.g., below interfaces where fine material overlays coarser material), (3) gas exsolution and growth are enhanced when the contrast between the two types of porous media is greater, and (4) in coarser material, gas phase gets distributed more uniformly whereas in finer materials, localized gas flow paths tend to form. Further research is ongoing into the dimensionality of these processes through experiments conducted in an intermediate scale two-dimensional tank. Various numerical tools are also being tested for their ability to simulate these processes.

Plampin, M. R.; Sakaki, T.; Pawar, R. J.; Illangasekare, T. H.

2012-12-01

122

A Study of the Relationship of Geological Formation to the NORM  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During quarter twelve of this project, final project revisions were approved and work initiated under these revisions. We have also made contact with regards to identifying new sampling sites.

Bursh, Talmage P.; Chriss, Derald

1999-10-28

123

Aspherical structural heterogeneity within the uppermost inner core: Insights into the hemispherical boundaries and core formation  

NASA Astrophysics Data System (ADS)

Lateral heterogeneities at the top of the inner core are investigated using earthquakes that occurred in Indonesia and southeast Asia and were recorded in the southeastern Caribbean. Using seismic observations of attenuation and seismic velocity, we were able to constrain the characteristics of the boundary between the inner and outer core to further investigate the dynamics and evolution of the Earth’s core. Our seismic observations from core phases confirm that the outermost inner core is asymmetrically heterogeneous and we are able to further constrain the morphology and physical properties of this layer. Comparison of data from earthquakes with ray paths traversing from east to the west versus those with ray paths from west to east allow us to map the aspherical heterogeneity of the boundary layer and specifically image the boundary between the proposed quasi-eastern and western hemispheres of the inner core. The variation of differential travel times between PKPdf and PKPbc, attenuation in terms of Q factor, and latitudinal changes for both of these observations, can be attributed to localized heterogeneity at the quasi-hemispherical boundaries of the inner core. We constrain the change in the thickness of outermost core boundary layer from 100 to 250 km within a distance of a few 10s of kilometers at 45°E ± 2°, for the western boundary, with an overall P-wave velocity decrease in the western hemisphere of 0.5% and increase of 0.5% in the eastern hemisphere. We constrain the eastern boundary at latitudes greater than 45°N to 173°E ± 4° with an overall P-wave velocity decrease in the western hemisphere of 1.0% in the uppermost 200 km of the inner core. The eastern boundary at equatorial latitudes is constrained to a region <170°E with a western hemisphere with a 0.5% drop in P-wave velocity in the uppermost 250 km.

Miller, Meghan S.; Niu, Fenglin; Vanacore, Elizabeth A.

2013-10-01

124

Multiscale heterogeneity characterization of tidal channel, tidal delta and foreshore facies, Almond Formation outcrops, Rock Springs uplift, Wyoming  

SciTech Connect

In order to accurately predict fluid flow within a reservoir, variability in the rock properties at all scales relevant to the specific depositional environment needs to be taken into account. The present work describes rock variability at scales from hundreds of meters (facies level) to millimeters (laminae) based on outcrop studies of the Almond Formation. Tidal channel, tidal delta and foreshore facies were sampled on the eastern flank of the Rock Springs uplift, southeast of Rock Springs, Wyoming. The Almond Fm. was deposited as part of a mesotidal Upper Cretaceous transgressive systems tract within the greater Green River Basin. Bedding style, lithology, lateral extent of beds of bedsets, bed thickness, amount and distribution of depositional clay matrix, bioturbation and grain sorting provide controls on sandstone properties that may vary more than an order of magnitude within and between depositional facies in outcrops of the Almond Formation. These features can be mapped on the scale of an outcrop. The products of diagenesis such as the relative timing of carbonate cement, scale of cemented zones, continuity of cemented zones, selectively leached framework grains, lateral variability of compaction of sedimentary rock fragments, and the resultant pore structure play an equally important, although less predictable role in determining rock property heterogeneity. A knowledge of the spatial distribution of the products of diagenesis such as calcite cement or compaction is critical to modeling variation even within a single facies in the Almond Fin. because diagenesis can enhance or reduce primary (depositional) rock property heterogeneity. Application of outcrop heterogeneity models to the subsurface is greatly hindered by differences in diagenesis between the two settings. The measurements upon which this study is based were performed both on drilled outcrop plugs and on blocks.

Schatzinger, R.A.; Tomutsa, L. [BDM Petroleum Technologies, Bartlesville, OK (United States)

1997-08-01

125

Risk-Based Management of Contaminated Groundwater: The Role of Geologic Heterogeneity, Exposure and Cancer Risk in Determining the Performance of Aquifer Remediation  

SciTech Connect

The effectiveness of aquifer remediation is typically expressed in terms of a reduction in contaminant concentrations relative to a regulated maximum contaminant level (MCL), and is usually confined by sparse monitoring data and/or simple model calculations. Here, the effectiveness of remediation is examined from a risk-based perspective that goes beyond the traditional MCL concept. A methodology is employed to evaluate the health risk to individuals exposed to contaminated household water that is produced from groundwater. This approach explicitly accounts for differences in risk arising from variability in individual physiology and water use, the uncertainty in estimating chemical carcinogenesis for different individuals, and the uncertainties and variability in contaminant concentrations within groundwater. A hypothetical contamination scenario is developed as a case study in a saturated, alluvial aquifer underlying a real Superfund site. A baseline (unremediated) human exposure and health risk scenario, as induced by contaminated groundwater pumped from this site, is predicted and compared with a similar estimate based upon pump-and-treat exposure intervention. The predicted reduction in risk in the remediation scenario is not an equitable one--that is, it is not uniform to all individuals within a population and varies according to the level of uncertainty in prediction. The importance of understanding the detailed hydrogeologic connections that are established in the heterogeneous geologic regime between the contaminated source, municipal receptors, and remediation wells, and its relationship to this uncertainty is demonstrated. Using two alternative pumping rates, we develop cost-benefit curves based upon reduced exposure and risk to different individuals within the population, under the presence of uncertainty.

Maxwell, R.M.; Carle, S.F.; Tompson, A.F.B.

2000-04-07

126

A Study of the Relationship of Geological Formation to the NORM, Quarterly Report  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During quarter seventeen of this project, work has continued under the project's approved revisions. We have received the first of our produced water samples and the samples have been analyzed for NORM activity. Additional tests are also being performed. We are also attempting to acquire samples from additional sites.

Bursh, Talmage P.; Chriss, Derald

1999-10-28

127

A Study of the Relationship of Geological Formation to the NORM  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During quarter sixteen of this project, work has continued under the approved revisions. We have received the first of our produced water samples and analysis is underway. In addition, the QA/QC plans have been completed and are currently being implemented.

Bursh, Talmage P.; Chriss, Derald

1999-10-28

128

A Study of the Relationship of Geological Formation to the NORM  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During quarter fifteen of this project, work has continued under the recently approved revisions. We have selected sampling sites and are awaiting samples for analysis. In addition, the QA/QC plans are in the final stages in anticipation of sample acquisition.

Bursh, Talmage P.; Chriss, Derald

1999-10-28

129

A Study of the Relationship of Geological Formation to the NORM  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During the tenth quarter of this project, emphasis again remained on two major tasks; identifying new sampling sites and seeking approval for final project revisions. In light of the delays experienced, the project has been granted a one year extension, and a revision is currently under review.

Bursh, Talmage P.; Chriss, Derald

1999-10-28

130

Chemical composition and geologic history of saline waters in Aux Vases and Cypress Formations, Illinois Basin  

USGS Publications Warehouse

Seventy-six samples of formation waters were collected from oil wells producing from the Aux Vases or Cypress Formations in the Illinois Basin. Forty core samples of the reservoir rocks were also collected from the two formations. Analyses of the samples indicated that the total dissolved solids content (TDS) of the waters ranged from 43,300 to 151,400 mg/L, far exceeding the 35,400 mg/mL of TDS found in typical seawater. Cl-Br relations suggested that high salinities in the Aux Vases and Cypress formation waters resulted from the evaporation of original seawater and subsequent mixing of the evaporated seawater with concentrated halite solutions. Mixing with the halite solutions increased Na and Cl concentrations and diluted the concentration of other ions in the formation waters. The elemental concentrations were influenced further by diagenetic reactions with silicate and carbonate minerals. Diagenetic signatures revealed by fluid chemistry and rock mineralogy delineated the water-rock interactions that took place in the Aux Vases and Cypress sandstones. Dissolution of K-feldspar released K into the solution, leading to the formation of authigenic illite and mixed-layered illite/smectite. Some Mg was removed from the solution by the formation of authigenic chlorite and dolomite. Dolomitization, calcite recrystallization, and contribution from clay minerals raised Sr levels significantly in the formation waters. The trend of increasing TDS of the saline formation waters with depth can be explained with density stratification. But, it is difficult to explain the combination of the increasing TDS and increasing Ca/Na ratio with depth without invoking the controversial 'ion filtration' mechanism.

Demir, I.; Seyler, B.

1999-01-01

131

Monitoring of CO 2 plumes during storage in geological formations using temperature signals: Numerical investigation  

Microsoft Academic Search

Carbon dioxide (CO2) injection into a storage formation is accompanied by non-isothermal effects. These are caused by a CO2 injection temperature that does not correspond to the formation temperature, cooling of the carbon dioxide due to expansion (Joule–Thomson cooling) and heat of dissolution of CO2 in brine. During flow in the subsurface, the carbon dioxide transports energy (advective heat transport)

Andreas Bielinski; Andreas Kopp; Hartmut Schütt

2008-01-01

132

Geology of upper member of Buckner formation, Hayesville field area, Claiborne Parish, Louisiana  

Microsoft Academic Search

Haynesville is the largest of the Arkansas-Louisiana shelf-slope fields which are productive from calcarenites of the upper members of the Late Jurassic Smackover and Buckner formations. Although associated with closure against a post-Smackover fault, hydrocarbon accumulation in the Haynesville field is stratigraphically controlled. Contrary to widespread belief, the main producing zone is part of the Buckner Formation, rather than Smackover,

1971-01-01

133

Forward Modeling of the Induction Log Response of a Fractured Geologic Formation  

E-print Network

is a very powerful tool that provides valuable information to industry and researchers. Any way to further develop this proven method is beneficial. Whether it is characterizing hydro-fracking jobs or evaluating formations in exploration... is a very powerful tool that provides valuable information to industry and researchers. Any way to further develop this proven method is beneficial. Whether it is characterizing hydro-fracking jobs or evaluating formations in exploration...

Bray, Steven Hunter

2013-05-02

134

The formation and functional consequences of heterogeneous mitochondrial distributions in skeletal muscle  

PubMed Central

SUMMARY Diffusion plays a prominent role in governing both rates of aerobic metabolic fluxes and mitochondrial organization in muscle fibers. However, there is no mechanism to explain how the non-homogeneous mitochondrial distributions that are prevalent in skeletal muscle arise. We propose that spatially variable degradation with dependence on O2 concentration, and spatially uniform signals for biogenesis, can account for observed distributions of mitochondria in a diversity of skeletal muscle. We used light and transmission electron microscopy and stereology to examine fiber size, capillarity and mitochondrial distribution in fish red and white muscle, fish white muscle that undergoes extreme hypertrophic growth, and four fiber types in mouse muscle. The observed distributions were compared with those generated using a coupled reaction-diffusion/cellular automata (CA) mathematical model of mitochondrial function. Reaction-diffusion analysis of metabolites such as oxygen, ATP, ADP and PCr involved in energy metabolism and mitochondrial function were considered. Coupled to the reaction-diffusion approach was a CA approach governing mitochondrial life cycles in response to the metabolic state of the fiber. The model results were consistent with the experimental observations and showed higher mitochondrial densities near the capillaries because of the sometimes steep gradients in oxygen. The present study found that selective removal of mitochondria in the presence of low prevailing local oxygen concentrations is likely the primary factor dictating the spatial heterogeneity of mitochondria in a diversity of fibers. The model results also suggest decreased diffusional constraints corresponding to the heterogeneous mitochondrial distribution assessed using the effectiveness factor, defined as the ratio of the reaction rate in the system with finite rates of diffusion to that in the absence of any diffusion limitation. Thus, the non-uniform distribution benefits the muscle fiber by increasing the energy status and increasing sustainable metabolic rates. PMID:22573766

Pathi, B.; Kinsey, S. T.; Howdeshell, M. E.; Priester, C.; McNeill, R. S.; Locke, B. R.

2012-01-01

135

Geologic Sequestration of CO2: Potential Permeability Changes in Host Formations of the San Juan Basin, New Mexico  

NASA Astrophysics Data System (ADS)

Terrestrial sequestration through injection into geologic formations is one proposed method for the isolation of anthropogenic CO2 from the atmosphere. A variety of physical and chemical processes are known to occur both during and after geologic CO2 injection, including diagenetic chemical reactions and associated permeability changes. Although it is commonly assumed that CO2 sequestered in this way will ultimately become mineralized, the rates of these changes, including CO2 hydration in brines, are known to be relatively slow. Bond and others (this volume) have developed a biomimetic approach to CO2 sequestration, in which the rate of CO2 hydration is accelerated by the use of a biological catalyst. Together with the hydrated CO2, cations from produced brines may be used to form solid-state carbonate minerals at the earth's surface, or this bicarbonate solution may be reinjected for geologic sequestration. Chemical composition of produced brines will affect both the diagenetic reactions that occur within the host formation, and the precipitation reactions that will occur above ground. In a specific case study of the San Juan Basin, New Mexico, we are cataloging different brines present in that basin. We are using this information to facilitate evaluation of potential applications of the biomimetic process and geologic sequestration. In a separate collaborative study by Grigg and others (this volume), laboratory experiments have been conducted on multiphase CO2 and brine injection and flow through saturated rock cores. We are extending from that study to our specific case study of the San Juan basin, to examine and characterize potential permeability changes associated with accelerated diagenesis due to the presence of high concentrations of CO2 or bicarbonate solutions in situ. We are developing and conducting new laboratory experiments to evaluate relative permeability (to CO2 and brine) of selected strata from the Fruitland Formation and Pictured Cliffs Sandstone. In addition to relative permeability, we are conducting longer-term flow tests reflecting marked permeability changes, and documenting the changes by comparing detailed pre-test measurements of porosity and permeability to post-test measurements. We are using these experimental results to parameterize coupled-flow and reactive-chemistry models of a selected cross-section of the San Juan basin. Our flow and chemistry model is based on the Los Alamos National Laboratory reactive chemistry simulator, TRANS, coupled to the Lawrence Berkeley Laboratory flow simulator, TOUGH2. The purpose of these simulation models is to evaluate potential CO2- and bicarbonate-induced diagenetic changes in permeability and flow at the basin-scale. In addition they will provide useful information in relation to brine extraction. We are also using these calibrated basin models to examine natural diagenesis and permeability evolution associated with changing brine properties and flow conditions over geologic time.

Abel, A. P.; McPherson, B.; Lichtner, P.; Bond, G.; Stringer, J.; Grigg, R.

2002-12-01

136

Geological Sequestration of CO2 by Hydrous Carbonate Formation with Reclaimed Slag  

SciTech Connect

The concept of this project is to develop a process that improves the kinetics of the hydrous carbonate formation reaction enabling steelmakers to directly remove CO2 from their furnace exhaust gas. It is proposed to bring the furnace exhaust stream containing CO2 in contact with reclaimed steelmaking slag in a reactor that has an environment near the unit activity of water resulting in the production of carbonates. The CO2 emissions from the plant would be reduced by the amount sequestered in the formation of carbonates. The main raw materials for the process are furnace exhaust gases and specially prepared slag.

Von L. Richards; Kent Peaslee; Jeffrey Smith

2008-02-06

137

INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO  

SciTech Connect

The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 2 of the project has been reservoir characterization, 3-D modeling and technology transfer. This effort has included six tasks: (1) the study of rockfluid interactions, (2) petrophysical and engineering characterization, (3) data integration, (4) 3-D geologic modeling, (5) 3-D reservoir simulation and (6) technology transfer. This work was scheduled for completion in Year 2. Overall, the project work is on schedule. Geoscientific reservoir characterization is essentially completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions is near completion. Observations regarding the diagenetic processes influencing pore system development and heterogeneity in these reef and shoal reservoirs have been made. Petrophysical and engineering property characterization has been essentially completed. Porosity and permeability data at Appleton and Vocation Fields have been analyzed, and well performance analysis has been conducted. Data integration is up to date, in that, the geological, geophysical, petrophysical and engineering data collected to date for Appleton and Vocation Fields have been compiled into a fieldwide digital database. 3-D geologic modeling of the structures and reservoirs at Appleton and Vocation Fields has been completed. The model represents an integration of geological, petrophysical and seismic data. 3-D reservoir simulation of the reservoirs at Appleton and Vocation Fields has been completed. The 3-D geologic model served as the framework for the simulations. A technology workshop on reservoir characterization and modeling at Appleton and Vocation Fields was conducted to transfer the results of the project to the petroleum industry.

Ernest A. Mancini

2002-09-25

138

An allometric model of home range formation explains the structuring of animal communities exploiting heterogeneous resources  

E-print Network

106 An allometric model of home range formation explains the structuring of animal communities. Buchmann (buchmann@uni-potsdam.de), F. M. Schurr and F. Jeltsch, Dept of Plant Ecology and Nature Conservation, Inst. of Biochemistry and Biology, Univ. of Potsdam, Maulbeerallee 2, DE­14469 Potsdam, Germany

Nathan, Ran

139

Planetary and Space Science 56 (2008) 289302 Periods of active permafrost layer formation during the geological  

E-print Network

Planetary and Space Science 56 (2008) 289­302 Periods of active permafrost layer formation during July 2005; accepted 2 February 2006 Available online 29 August 2007 Abstract Permafrost is ground. An active layer in permafrost regions is defined as a near-surface layer that undergoes freeze­thaw cycles

Marchant, David R.

140

Technique of Formation of an Axisymmetric Heterogeneous Flow During Thermal Spraying of Powder Materials  

NASA Astrophysics Data System (ADS)

The paper presents an investigation of a unit of annular injection of powder materials into a thermal plasma flow. The unit is designed for the electric-arc direct-current plasma torch with a sectioned inter-electrode insert up to 100 kW, which was developed earlier. Energy characteristics (thermal efficiency and thermal power of the plasma jet) and spectra of plasma torch current and voltage fluctuations are described. The characteristics of the radial temperature distribution in the plasma jet in the annular and point powder injection cases are compared. A multi-channel spectrometer with a photo-diode array was implemented for the measurements. It is shown that, in contrast to point injection of powder particles, which is carried out across the jet on the nozzle exit, distributed annular injection with gas-dynamic focusing provides a dense axisymmetric heterogeneous flow, in which almost all particles pass through a high-temperature and high-speed area near the plasma jet axis.

Kuz'min, V. I.; Mikhal'Chenko, A. A.; Kovalev, O. B.; Kartaev, E. V.; Rudenskaya, N. A.

2012-01-01

141

Geologic map of the Peach Orchard Flat quadrangle, Carbon County, Wyoming, and descriptions of new stratigraphic units in the Upper Cretaceous Lance Formation and Paleocene Fort Union Formation, eastern Greater Green River Basin, Wyoming-Colorado  

USGS Publications Warehouse

This report provides a geologic map of the Peach Orchard Flat 7.5-minute quadrangle, located along the eastern flank of the Washakie Basin, Wyo. Geologic formations and individual coal beds were mapped at a scale of 1:24,000; surface stratigraphic sections were measured and described; and well logs were examined to determine coal correlations and thicknesses in the subsurface. In addition, four lithostratigraphic units were named: the Red Rim Member of the Upper Cretaceous Lance Formation, and the China Butte, Blue Gap, and Overland Members of the Paleocene Fort Union Formation.

Honey, J. D.; Hettinger, R. D.

2004-01-01

142

Leveraging Regional Exploration to Develop Geologic Framework for CO2 Storage in Deep Formations in Midwestern United States  

SciTech Connect

Obtaining subsurface data for developing a regional framework for geologic storage of CO{sub 2} can require drilling and characterization in a large number of deep wells, especially in areas with limited pre-existing data. One approach for achieving this objective, without the prohibitive costs of drilling costly standalone test wells, is to collaborate with the oil and gas drilling efforts in a piggyback approach that can provide substantial cost savings and help fill data gaps in areas that may not otherwise get characterized. This leveraging with oil/gas drilling also mitigates some of the risk involved in standalone wells. This collaborative approach has been used for characterizing in a number of locations in the midwestern USA between 2005 and 2009 with funding from U.S. Department of Energy's National Energy Technology Laboratory (DOE award: DE-FC26-05NT42434) and in-kind contributions from a number of oil and gas operators. The results are presented in this final technical report. In addition to data collected under current award, selected data from related projects such as the Midwestern Regional Carbon Sequestration Partnership (MRCSP), the Ohio River Valley CO{sub 2} storage project at and near the Mountaineer Plant, and the drilling of the Ohio Stratigraphic well in Eastern Ohio are discussed and used in the report. Data from this effort are also being incorporated into the MRCSP geologic mapping. The project activities were organized into tracking and evaluation of characterization opportunities; participation in the incremental drilling, basic and advanced logging in selected wells; and data analysis and reporting. Although a large number of opportunities were identified and evaluated, only a small subset was carried into the field stage. Typical selection factors included reaching an acceptable agreement with the operator, drilling and logging risks, and extent of pre-existing data near the candidate wells. The region of study is primarily along the Ohio River Valley corridor in the Appalachian Basin, which underlies large concentrations of CO{sub 2} emission sources. In addition, some wells in the Michigan basin are included. Assessment of the geologic and petrophysical properties of zones of interest has been conducted. Although a large number of formations have been evaluated across the geologic column, the primary focus has been on evaluating the Cambrian sandstones (Mt. Simon, Rose Run, Kerbel) and carbonates layers (Knox Dolomite) as well as on the Silurian-Devonian carbonates (Bass Island, Salina) and sandstones (Clinton, Oriskany, Berea). Factors controlling the development of porosity and permeability, such as the depositional setting have been explored. In northern Michigan the Bass Islands Dolomite appears to have favorable reservoir development. In west central Michigan the St. Peter sandstone exhibits excellent porosity in the Hart and Feuring well and looks promising. In Southeastern Kentucky in the Appalachian Basin, the Batten and Baird well provided valuable data on sequestration potential in organic shales through adsorption. In central and eastern Ohio and western West Virginia, the majority of the wells provided an insight to the complex geologic framework of the relatively little known Precambrian through Silurian potential injection targets. Although valuable data was acquired and a number of critical data gaps were filled through this effort, there are still many challenges ahead and questions that need answered. The lateral extent to which favorable potential injection conditions exist in most reservoirs is still generally uncertain. The prolongation of the characterization of regional geologic framework through partnership would continue to build confidence and greatly benefit the overall CO{sub 2} sequestration effort.

Neeraj Gupta

2009-09-30

143

Pore-space alteration induced by brine acidification in subsurface geologic formations  

NASA Astrophysics Data System (ADS)

A new Lagrangian particle-based method is presented to simulate reactive transport in natural porous media. This technique is based on Modified Moving Particle Semi-implicit (MMPS) and takes as input high-resolution voxel images of natural porous media. The flow field in the medium is computed by solving the incompressible Navier-Stokes equations. Moreover, a multicomponent ion transport model is coupled with a homogeneous and heterogeneous reactions module to handle pore-space alteration (i.e., pore-wall dissolution). The model is first successfully validated against the experimental data available in the literature. Subsequently, X-ray microtomographic images of two naturally occurring porous media are used to investigate the impact of reaction kinetics and pore-space topology on pore-space alteration induced by brine acidification in subsurface conditions. We observed that at the normal rates of reactions no significant change in porosity and permeability takes place in the short term. Whereas, higher reaction rates caused major changes in the macroscopic properties (e.g., porosity and permeability) of the rocks. We also show that these changes are strongly affected by the rocks' pore-scale topologies.

Ovaysi, Saeed; Piri, Mohammad

2014-01-01

144

An aqueous rechargeable formate-based hydrogen battery driven by heterogeneous pd catalysis.  

PubMed

The formate-based rechargeable hydrogen battery (RHB) promises high reversible capacity to meet the need for safe, reliable, and sustainable H2 storage used in fuel cell applications. Described herein is an additive-free RHB which is based on repetitive cycles operated between aqueous formate dehydrogenation (discharging) and bicarbonate hydrogenation (charging). Key to this truly efficient and durable H2 handling system is the use of highly strained Pd nanoparticles anchored on graphite oxide nanosheets as a robust and efficient solid catalyst, which can facilitate both the discharging and charging processes in a reversible and highly facile manner. Up to six repeated discharging/charging cycles can be performed without noticeable degradation in the storage capacity. PMID:25382034

Bi, Qing-Yuan; Lin, Jian-Dong; Liu, Yong-Mei; Du, Xian-Long; Wang, Jian-Qiang; He, He-Yong; Cao, Yong

2014-12-01

145

Local-heterogeneous responses and transient dynamics of cage breaking and formation in colloidal fluids  

NASA Astrophysics Data System (ADS)

Quantifying the interactions in dense colloidal fluids requires a properly designed order parameter. We present a modified bond-orientational order parameter, bar{? }6, to avoid problems of the original definition of bond-orientational order parameter. The original bond-orientational order parameter can change discontinuously in time but our modified order parameter is free from the discontinuity and, thus, it is a suitable measure to quantify the dynamics of the bond-orientational ordering of the local surroundings. Here we analyze bar{? }6 in a dense driven monodisperse quasi-two-dimensional colloidal fluids where a single particle is optically trapped at the center. The perturbation by the trapped and driven particle alters the structure and dynamics of the neighboring particles. This perturbation disturbs the flow and causes spatial and temporal distortion of the bond-orientational configuration surrounding each particle. We investigate spatio-temporal behavior of bar{? }6 by a Wavelet transform that provides a time-frequency representation of the time series of bar{? }6. It is found that particles that have high power in frequencies corresponding to the inverse of the timescale of perturbation undergo distortions of their packing configurations that result in cage breaking and formation dynamics. To gain insight into the dynamic structure of cage breaking and formation of bond-orientational ordering, we compare the cage breaking and formation dynamics with the underlying dynamical structure identified by Lagrangian Coherent Structures (LCSs) estimated from the finite-time Lyapunov exponent (FTLE) field. The LCSs are moving separatrices that effectively divide the flow into distinct regions with different dynamical behavior. It is shown that the spatial distribution of the FTLE field and the power of particles in the wavelet transform have positive correlation, implying that LCSs provide a dynamic structure that dominates the dynamics of cage breaking and formation of the colloidal fluids.

Nag, Preetom; Teramoto, Hiroshi; Li, Chun-Biu; Terdik, Joseph Z.; Scherer, Norbert F.; Komatsuzaki, Tamiki

2014-09-01

146

The geology and mechanics of formation of the Fort Rock Dome, Yavapai County, Arizona  

USGS Publications Warehouse

The Fort Rock Dome, a craterlike structure in northern Arizona, is the erosional product of a circular domal uplift associated with a Precambrian shear zone exposed within the crater and with Tertiary volcanism. A section of Precambrian to Quaternary rocks is described, and two Tertiary units, the Crater Pasture Formation and the Fort Rock Creek Rhyodacite, are named. A mathematical model of the doming process is developed that is consistent with the history of the Fort Rock Dome.

Fuis, Gary S.

1996-01-01

147

The geology and mineralogy of Ritchey crater, Mars: Evidence for post-Noachian clay formation  

NASA Astrophysics Data System (ADS)

detection of phyllosilicates (clay minerals) in Noachian (>3.5 Ga) terrains on Mars and their paucity in younger terrains have led to the hypothesis that Noachian conditions were more clement than the colder, drier conditions that have since followed. However, recent clay detections in several Hesperian impact craters suggest that fluvial transport and alteration were possible after the posited early era of phyllosilicate formation. Here we present evidence that rocks within Hesperian age Ritchey crater (28.5°S, 51°W) record a period of post-Noachian fluvial transport and in situ alteration. This resulted in the transport of clays from the crater wall to the crater floor and the formation of hydrated silica and Fe/Mg smectite in Ritchey's central uplift. Clay minerals associated with central uplifts are commonly interpreted to represent preexisting clays excavated from depth, potentially providing insight into older crustal clay-forming processes. Here we present detailed geomorphic and mineralogic maps and show that the clays in Ritchey's central peak formed after or as a direct result of the impact and are thus Hesperian or younger. Clays on the crater wall were either preexisting clays exposed by the impact or formed in situ through postimpact water-rock interaction. In either scenario, some of these clays were likely subsequently transported to the crater floor by fluvial-alluvial processes in a source-to-sink system. In this context, the hydrated phases in Ritchey indicate several different formation and transport mechanisms and provide further evidence that near-surface clay mineral formation, and thus habitable conditions, existed on Mars after the Noachian.

Sun, Vivian Z.; Milliken, Ralph E.

2014-04-01

148

The geology of Svalbard: structural, stratigraphic and geomorphic response to the formation of two passive margins  

NASA Astrophysics Data System (ADS)

Svalbard is located at the junction of the North Atlantic and Arctic margins, preserves an onshore structural and stratigraphic record that spans from the Devonian to the Cenozoic and records several phases of extension characterized by different tectonic transport vectors. Contractional events such as the Devonian, so-called 'Svalbardian' fold phase and the formation of an Early Cenozoic fold and thrust belt have locally modified the evidence for extension and basin formation. However, several generations of extensional structures and associated, tectonically controlled basins are displayed in world-class exposures at different locations in the archipelago. At present, we focus on the following onshore features related to extension and margin formation: 1. Late-post orogenic extension: An extensional detachment and metamorphic core complex was recently identified by us in northwestern Spitsbergen, involving re-interpretation of tectonic contacts interpreted previously as thrusts. The undulating extensional detachment appears to have controlled 'Old Red' basin formation from the Early into the Late Devonian. The core complex evolved into a N-S trending anticline with flanks that eventually became the locus of strike-slip and normal faulting. Some of these faults were demonstrably reactivated, and we propose that the Devonian structural template became important in controlling the location of later rift structures that developed from the Carboniferous onwards. 2. Carboniferous rifting: Normal faulting controlled sedimentation in Carboniferous basins including an up to 2 km deep, coastal/marine half-graben with mixed siliclastic, carbonate and evaporite fill exposed in Central Spitsbergen. The Billefjorden Fault zone (BFZ) reactivates an older, N-S trending Devonian reverse fault, and coarse siliclastic debris was transported into the basin along relay ramps that developed between the normally reactivated strands of the BFZ. Monoclinal folds, interpreted previously as Tertiary compressional features, were recently re-interpreted by two of the present authors as extensional fault-growth monoclines, similar to structures described by others from the Gulf of Suez. 3. Late Triassic normal faulting: Spectacular outcrops of syntectonic half-graben basins occur in the lower parts of the Late Triassic Deltaic DeGeerdal formation on Edge Island. The intricate architecture of sandbodies revealed by the half-graben basins can be used to decipher in detail the relationships between accommodation and sediment supply. The half-graben reveal several periods of hangingwall-directed progradation of sandy units over prodelta shales, catastrophic deposition of massive massflow sandstone wedges and the subsequent burial of these under marine shales or channel sandstone units. 4. Differential uplift, incision and landscape formation. Northwards incision of stratigraphy due to differential uplift in the Cretaceous, incision of widespread geomorphic surfaces into Palaeogene strata and the uplift of these to a 1000 metres altitude show that significant vertical movements accompanied the evolution of the margins. Pronounced variations in landscape across the archipelago and even a quaternary volcano situated on a neotectonic fault-line attests further to a large research potential with respect to the onshore response to margin formation in the Arctic and Northernmost North Atlantic.

Osmundsen, P. T.; Braathen, A.; Maher, H.

2012-04-01

149

Geology of the BK9 kimberlite (Damtshaa, Botswana): implications for the formation of dark volcaniclastic kimberlite  

NASA Astrophysics Data System (ADS)

The BK9 kimberlite consists of three overlapping pipes. It contains two dark varieties of massive volcaniclastic kimberlite, informally termed dark volcaniclastic kimberlite (DVK). DVK(ns) is present in the north and south pipes and is interbedded with lenses of basalt breccia at the margins of the pipes. DVK(c) is present within the central pipe where it is overlain by a sequence of basalt breccias with interbedded volcanogenic sediments. The features observed within the DVK units of the BK9 kimberlite provide strong evidence for gas fluidisation of the accumulating pyroclastic material. These include the massive interior of the pipes, marginal epiclastic units, well-dispersed country-rock xenoliths and small-scale heterogeneities in lithic clast abundance. The upper portions of the central pipe provide a record of the transition from pyroclastic eruption and infill to passive epiclastic infilling of the crater, after the eruption has ceased. The wall-rock of the BK9 kimberlite dips inwards and is interpreted as post pipe-fill subsidence of the adjacent country rock. The two DVK units contain interstitial, silt-sized pyroclasts. The DVK(ns) has a higher fraction of former melt and displays evidence of incipient welding, as a result of differences in eruption dynamics. These units demonstrate that whilst DVK is comparable in many respects to MVK and forms part of a spectrum of volcaniclastic rocks formed by fluidisation, it differs in frequently containing silt-sized particles and including agglutinated and welded varieties with a high melt fraction. The DVK varieties, studied here, also have a distinctive hydrothermal assemblage, resulting from the abundance of low-silica accidental lithic clasts. Both the hydrothermal alteration and the abundance of silt-sized particles contribute to the DVKs distinctive dark colour.

Buse, B.; Sparks, R. S. J.; Field, M.; Schumacher, J. C.; Chisi, K.; Tlhaodi, T.

2011-10-01

150

Pore-scale study of capillary trapping mechanism during CO2 injection in geological formations  

SciTech Connect

Geological sequestration of CO{sub 2} gas emerged as a promising solution for reducing amount of green house gases in atmosphere. A number of continuum scale models are available to describe the transport phenomena of CO{sub 2} sequestration. These models rely heavily on a phenomenological description of subsurface transport phenomena and the predictions can be highly uncertain. Pore-scale models provide a better understanding of fluid displacement processes, nonetheless such models are rare. In this work we use a Smoothed Particle Hydrodynamics (SPH) model to study pore-scale displacement and capillary trapping mechanisms of super-critical CO{sub 2} in the subsurface. Simulations are carried out to investigate the effects of gravitational, viscous, and capillary forces in terms of Gravity, Capillary, and Bond numbers. Contrary to the other published continuum scale investigations, we found that not only Gravity number but also Capillary number plays an important role on the fate of injected CO{sub 2}. For large Gravity numbers (on the order of 10), most of the injected CO{sub 2} reaches the cap-rock due to gravity segregation. A significant portion of CO{sub 2} gets trapped by capillary forces when Gravity number is small (on the order of 0.1). When Gravity number is moderately high (on the order of 1), trapping patterns are heavily dependent on Capillary number. If Capillary number is very small (less than 0.001), then capillary forces dominate the buoyancy forces and a significant fraction of injected CO{sub 2} is trapped by the capillary forces. Conversely, if Capillary number is high (higher than 0.001), capillary trapping is relatively small since buoyancy dominates the capillary forces. In addition, our simulations reveal different types of capillary trapping and flow displacement mechanisms during and after injection. In gravity dominated cases leave behind was the widespread trapping mechanism. Division was the primary trapping mechanism in viscous dominated cases. In capillary dominated cases, snap-off of the CO{sub 2} plume is the most commonly observed displacement mechanism. Large CO{sub 2} blobs are created due to coalescence mechanism.

Bandara, Uditha C.; Tartakovsky, Alexandre M.; Palmer, Bruce J.

2011-11-01

151

Multi-Scale Modeling of CO2 and Brine Flow in Geologic Formations Containing Faults  

NASA Astrophysics Data System (ADS)

Basins being considered for geologic storage of CO2 contain faults that can act as conduits for flow. The flow of CO2 and brine in and around faults involves relatively small-scale processes, when compared to typical grid-cell sizes in basin-scale numerical models. A computationally efficient approach to multi-phase flow modeling of basins containing faults can be developed based on embedding analytical solutions to represent small-scale features (like faults) within larger-scale numerical models. This approach is analogous to the use of analytical solutions for flow around wells as sub-scale corrections in numerical models (e.g. Peaceman (1978), Gasda et al. (2009)). However, the modeling approach for faults departs from wells due to the possibility of the fault extending beyond one numerical grid block, and its underlying Cartesian, rather than cylindrical, geometry. The combined analytical-numerical multi-scale (CAN-MS) model for faults is composed of (1) numerical approximation for the basin-scale flow system, (2) analytical solutions for the small-scale flow regimes for a given fault, and (3) the coupling between basin and small-scale flow systems. Following the approach of Nordbotten and Celia (2006) given in radial coordinates, analytical solutions representing different flow conditions in and around faults are derived in Cartesian coordinates for a stationary problem with a finite outer boundary. The solutions are based on mass conservation equations, Darcy's Law, and structured vertical flow to represent vertical non-equilibrium. These solutions are used to determine the fluxes along the fault and to derive pressure corrections that relate pressure at a given fault to the (average) pressure in the numerical grid blocks. The flow and pressure solutions are solved simultaneously to describe the small-scale effects of the fault and produce an output in a form that is compatible with the coarse-scale numerical model. Model test results will be presented to facilitate future application of the CAN-MS model to real basins such as the Illinois Basin.

Kang, M.; Nordbotten, J. M.; Celia, M. A.

2011-12-01

152

Heterogeneous Earth Accretion and Incomplete Metal-Silicate Reequilibration at High Pressure During Core Formation  

NASA Astrophysics Data System (ADS)

We present a new model of core formation, based on the partitioning of siderophile elements, that involves accreting the Earth through a series of collisions with smaller bodies that had already differentiated at low pressure. Each impact results in a magma ocean in which the core of the impactor reequilibrates with silicate liquid at high pressure before merging with the Earth's protocore. The oxygen contents of the chondritic compositions of the proto-Earth and impactors can be varied. The compositions of coexisting metal and silicate are determined through mass balance combined with partitioning equations for Ni, FeO, Si and other siderophile elements. The oxygen fugacity is fixed by the partitioning of FeO and is a function of P, T and bulk oxygen content. An important constraint for core formation is that core-mantle partition coefficients for Ni and Co must both converge to values of 23-28. Based on a recent study of the partitioning of Ni and Co over a wide P-T range (Kegler et al., EPSL, submitted) together with other published data, this constraint is not satisfied by a single- stage core formation model at any conditions because the partition coefficients converge at values that are much too low. In the present multi-stage model, the correct values can be reached if only part of each impactor core reequilibrates with silicate liquid in the magma ocean (as proposed by previous models based on Hf-W isotope studies). Physically, this would mean that impactor cores fail to emulsify completely as they sink through the magma ocean. Incorporating other elements (e.g. V and Cr) in the model requires, in addition, that the bulk composition of the impactors changes during accretion from reduced (FeO-poor) to oxidised FeO-rich). Then, with the resulting increase in fO2, incomplete reequilibration of the cores during the final 20-30% of Earth accretion is required to satisfy the Ni-Co constraint. In addition, this model enables the concentrations of O and Si in the core to be estimated.

Rubie, D. C.; Mann, U.; Frost, D. J.; Kegler, P.; Holzheid, A.; Palme, H.

2007-12-01

153

Survey of naturally occurring hazardous materials in deep geologic formations: a perspective on the relative hazard of deep burial of nuclear wastes  

Microsoft Academic Search

Hazards associated with deep burial of solidified nuclear waste are considered with reference to toxic elements in naturally occurring ore deposits. This problem is put into perspective by relating the hazard of a radioactive waste repository to that of naturally occurring geologic formations. The basis for comparison derives from a consideration of safe drinking water levels. Calculations for relative toxicity

K. A. Tonnessen; J. J. Cohen

1977-01-01

154

INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO  

SciTech Connect

The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling that utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 3 of the project has been reservoir characterization, 3-D modeling, testing of the geologic-engineering model, and technology transfer. This effort has included six tasks: (1) the study of seismic attributes, (2) petrophysical characterization, (3) data integration, (4) the building of the geologic-engineering model, (5) the testing of the geologic-engineering model and (6) technology transfer. This work was scheduled for completion in Year 3. Progress on the project is as follows: geoscientific reservoir characterization is completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions has been completed. Observations regarding the diagenetic processes influencing pore system development and heterogeneity in these reef and shoal reservoirs have been made. Petrophysical and engineering property characterization has been completed. Porosity and permeability data at Appleton and Vocation Fields have been analyzed, and well performance analysis has been conducted. Data integration is up to date, in that, the geological, geophysical, petrophysical and engineering data collected to date for Appleton and Vocation Fields have been compiled into a fieldwide digital database. 3-D geologic modeling of the structures and reservoirs at Appleton and Vocation Fields has been completed. The models represent an integration of geological, petrophysical and seismic data. 3-D reservoir simulation of the reservoirs at Appleton and Vocation Fields has been completed. The 3-D geologic models served as the framework for the simulations. The geologic-engineering models of the Appleton and Vocation Field reservoirs have been developed. These models are being tested. The geophysical interpretation for the paleotopographic feature being tested has been made, and the study of the data resulting from drilling of a well on this paleohigh is in progress. Numerous presentations on reservoir characterization and modeling at Appleton and Vocation Fields have been made at professional meetings and conferences and a short course on microbial reservoir characterization and modeling based on these fields has been prepared.

Ernest A. Mancini

2003-09-25

155

Thermal Decomposition of Gaseous Ammonium Nitrate at Low Pressure: Kinetic Modeling of Product Formation and Heterogeneous Decomposition of Nitric Acid  

NASA Astrophysics Data System (ADS)

The thermal decomposition of ammonium nitrate, NH4NO3 (AN), in the gas phase has been studied at 423-56 K by pyrolysis/mass spectrometry under low-pressure conditions using a Saalfeld reactor coated with boric acid. The sublimation of NH4NO3 at 423 K was proposed to produce equal amounts of NH3 and HNO3, followed by the decomposition reaction of HNO3, HNO3 + M ? OH + NO2 + M (where M = third-body and reactor surface). The absolute yields of N2, N2O, H2O, and NH3, which can be unambiguously measured and quantitatively calibrated under a constant pressure at 5-6.2 torr He are kinetically modeled using the detailed [H,N,O]-mechanism established earlier for the simulation of NH3-NO2 (Park, J.; Lin, M. C. Technologies and Combustion for a Clean Environment. Proc. 4th Int. Conf. 1997, 34-1, 1-5) and ADN decomposition reactions (Park, J.; Chakraborty, D.; Lin, M. C. Proc. Combust. Inst. 1998, 27, 2351-2357). Since the homogeneous decomposition reaction of HNO3 itself was found to be too slow to account for the consumption of reactants and the formation of products, we also introduced the heterogeneous decomposition of HNO3 in our kinetic modeling. The heterogeneous decomposition rate of HNO3, HNO3 + (B2O3/SiO2) ? OH + NO2 + (B2O3/SiO2), was determined by varying its rate to match the modeled result to the measured concentrations of NH3 and H2O; the rate could be represented by k2b = 7.91 × 107 exp(-12 600/T) s-1, which appears to be consistent with those reported by Johnston and co-workers (Johnston, H. S.; Foering, L.; Tao, Y.-S.; Messerly, G. H. J. Am. Chem. Soc. 1951, 73, 2319-2321) for HNO3 decomposition on glass reactors at higher temperatures. Notably, the concentration profiles of all species measured could be satisfactorily predicted by the existing [H,N,O]-mechanism with the heterogeneous initiation process.

Park, J.; Lin, M. C.

2009-10-01

156

Heterogeneous immunoassays in microfluidic format using fluorescence detection with integrated amorphous silicon photodiodes  

PubMed Central

Miniaturization of immunoassays through microfluidic technology has the potential to decrease the time and the quantity of reactants required for analysis, together with the potential of achieving multiplexing and portability. A lab-on-chip system incorporating a thin-film amorphous silicon (a-Si:H) photodiode microfabricated on a glass substrate with a thin-film amorphous silicon-carbon alloy directly deposited above the photodiode and acting as a fluorescence filter is integrated with a polydimethylsiloxane-based microfluidic network for the direct detection of antibody-antigen molecular recognition reactions using fluorescence. The model immunoassay used consists of primary antibody adsorption to the microchannel walls followed by its recognition by a secondary antibody labeled with a fluorescent quantum-dot tag. The conditions for the flow-through analysis in the microfluidic format were defined and the total assay time was 30 min. Specific molecular recognition was quantitatively detected. The measurements made with the a-Si:H photodiode are consistent with that obtained with a fluorescence microscope and both show a linear dependence on the antibody concentration in the nanomolar-micromolar range. PMID:21403847

Pereira, A. T.; Novo, P.; Prazeres, D. M. F.; Chu, V.; Conde, J. P.

2011-01-01

157

Relationship between Mineralogy and Porosity in Subsurface Formations Relevant to Geologic CO2 Sequestration  

NASA Astrophysics Data System (ADS)

Porosity and permeability are the key variables that link the thermal, hydrological, geochemical and geomechanical processes that redistribute mass and energy in response to injection of CO2 into the subsurface. The size, shape, distribution and connectivity of rock pores dictate how fluids migrate into and through these micro- and nanoenvironments, wet and react with the solid. The link between pore size distribution and connectivity and pore-wall mineralogy is still poorly constrained for both reservoir and caprocks.. The objectives of this effort are to characterize the nano- to macropore features, quantify mineral-specific reactive surface areas in both pore and fracture networks, and determine how pores and fractures evolve in reacted systems at temperature-pressure-composition conditions relevant to CO2 injection. Representative caprocks and reservoir rocks associated with CO2 injection activities (e.g. shallow buried quartz arenites from the St. Peter Sandstone and the deeper Mt. Simon sandstone in Ohio as well as the Eau Claire Formation shale and mudrocks) are being interrogated with an array of complementary methods - e.g. SEM, TEM, neutron scattering, X-ray CT, neutron tomography as well as conventional petrophysics. (Ultra)small-angle neutron scattering and autocorrelations derived from BSE imaging provide a powerful method of quantifying pore structures in a statistically significant manner from the nanometer to the centimeter scale. Results will be described comparing shale and mudrocks that indicate there are significant variations not only in terms of total nano- to micro-porosity and pore interconnectivity, but also in terms of pore surface fractal (roughness) and mass fractal (pore distributions) dimensions as well as size distributions. For tight formations we have observed that: (a) total porosity exhibiting bimodality may be typical of shale and mudstones, (b) connected porosity exhibiting bimodal tendencies may not be uncommon in shale and mudstone caprocks, (c) as expected, fissile shale contains far greater abundance of nanopores than do mudstones, (d) connected porosity also mimics the bimodal total porosity trends with connected nanopores observed below about 400 nm and connected micropores between 50 and 100 microns, (e) pore mineralogy (hence potential reactive surface area) is generally very different than the bulk mineralogy, especially for mudstones where phases present in minor abundances in the bulk may contribute more to the connected pore network. The data on sandstones suggest that nano- and microporosity are more prevalent in nominally coarse-grained lithologies and may play a more important role than previously thought in fluid/rock interactions. Information from imaging and scattering are being used to constrain computer-generated, random, three-dimensional porous structures. The results integrate various sources of experimental information and are statistically compatible with the real rock. These computerized porous matrices will then be used in CO2 sorption MD simulations.

Cole, D. R.; Swift, A.; Sheets, J.; Welch, S.; Anovitz, L. M.; Rother, G.; Vlcek, L.

2013-12-01

158

Petroleum geology of MC-3 member, Mississippian Mission Canyon Formation, Pierson area, southwestern Manitoba  

SciTech Connect

Mississippian beds in the Manitoba portion of the Williston basin produce oil from a series of stratigraphic units where porous cyclic carbonates are truncated by pre-Mesozoic erosion and sealed by Amaranth (Watrous/Spearfish) strata. In the Pierson area of southwest Manitoba, oil is trapped within the MC-3 member of the Mission Canyon Formation, correlative with the Alida beds of Saskatchewan. Production was first obtained in 1954 and subsequent exploration has led to the discovery of 11 pools of various sizes. As of December 31, 1987, 2.4 million bbl (375,510 m/sup 3/) of 36/degrees/ API gravity oil had been produced from the area, and currently eight pools are producing. In Manitoba, the Mission Canyon is subdivided into three members: MC-1, MC-2, and MC-3, in ascending order. The MC-3 is further subdivided by the MC-3 marker into lower MC-3a and upper MC-3b units. Oil, in the Pierson area, occurs in these two units. The MC-3 member consists of a cyclic sequence of lithofacies deposited in a shallow-water, moderate to high-energy, carbonate-dominated inner shelf environment that was present over much of southwest Manitoba. Five lithofacies have been recognized in core, but oil is found largely within the more porous shoal and backshoal facies (average porosity 14% and permeability 12 md). The cap rock, in most places, is a secondary, dense dolomite and anhydrite zone (altered zone) directly below the pre-Mesozoic erosion surface. Where the altered zone is thin or absent, lower Amaranth shales (red beds) form the cap rock. Entrapment is primarily stratigraphic, resulting from regional truncation of the MC-3 beds with accumulation localized and controlled by (1) local paleotopographic highs, (2) porosity and permeability pinch-out due to primary lithofacies variations, and (3) porosity closure resulting from variation in the thickness of the altered zone.

Husain, M.; Halabura, S.P.

1988-07-01

159

Geologic Map of Upper Cretaceous and Tertiary Strata and Coal Stratigraphy of the Paleocene Fort Union Formation, Rawlins-Little Snake River Area, South-Central Wyoming  

USGS Publications Warehouse

This report provides a map and detailed descriptions of geologic formations for a 1,250 square mile region in the Rawlins-Little Snake River coal field in the eastern part of the Washakie and Great Divide Basins of south-central Wyoming. Mapping of geologic formations and coal beds was conducted at a scale of 1:24,000 and compiled at a scale of 1:100,000. Emphasis was placed on coal-bearing strata of the China Butte and Overland Members of the Paleocene Fort Union Formation. Surface stratigraphic sections were measured and described and well logs were examined to determine the lateral continuity of individual coal beds; the coal-bed stratigraphy is shown on correlation diagrams. A structure contour and overburden map constructed on the uppermost coal bed in the China Butte Member is also provided.

Hettinger, R.D.; Honey, J.G.; Ellis, M.S.; Barclay, C.S.V.; East, J.A.

2008-01-01

160

Effect of modeling factors on the dissolution-diffusion-convection process during CO2 geological storage in deep saline formations  

NASA Astrophysics Data System (ADS)

It is well known that during CO2 geological storage, density-driven convective activity can significantly accelerate the dissolution of injected CO2 into water. This action could limit the escape of supercritical CO2 from the storage formation through vertical pathways such as fractures, faults and abandoned wells, consequently increasing permanence and security of storage. First, we investigated the effect of numerical perturbation caused by time and grid resolution and the convergence criteria on the dissolution-diffusion-convection (DDC) process. Then, using the model with appropriate spatial and temporal resolution, some uncertainty parameters investigated in our previous paper such as initial gas saturation and model boundaries, and other factors such as relative liquid permeability and porosity modification were used to examine their effects on the DDC process. Finally, we compared the effect of 2D and 3D models on the simulation of the DDC process. The above modeling results should contribute to clear understanding and accurate simulation of the DDC process, especially the onset of convective activity, and the CO2 dissolution rate during the convection-dominated stage.

Zhang, Wei

2013-06-01

161

Geological evolution and analysis of confirmed or suspected gas hydrate localities: Volume 2, basin analysis, formation and stability of gas hydrates in the Black Sea  

SciTech Connect

This document is Volume 11 of a series of reports entitled ''Geological Evolution and Analysis Confirmed or Suspected Gas Hydrate Localities.'' Volume 11 provides an analysis of the Black Sea region. The report presents a geological description of the Black Sea region, including regional and local structural settings, geomorphology, geological history, stratigraphy, and physical properties. Included also is a discussion of bottom simulating acoustic reflectors, sediment acoustic properties, distribution of hydrates within the sediments, and the relation of hydrate distribution to other features such as salt dispirism. The formation and stabilization of gas hydrates in sediments are discussed in terms of phase relations, nucleation, and crystallization constraints, gas solubility, pore fluid chemistry, inorganic diagenesis, and sediment organic content. A depositional analysis of the areas is discussed in order to better understand the thermal evolution of the locality and to assess the potential for thermogenic hydrocarbon generation. 80 refs., 27 figs., 16 tabs.

Ciesnik, M.S.; Krason, J.

1987-05-01

162

Dispersion measurement as a method of quantifying geologic characterization and defining reservoir heterogeneity. Annual report, July 12, 1990--September 12, 1991  

SciTech Connect

Since reservoirs are heterogeneous, nonuniform, and anisotropic, the success or failure of many enhanced oil recovery techniques rests on our prediction of internal variability and the paths of fluid flow in the reservoir. The main objective of this project is to develop a greater understanding of reservoir heterogeneities through dispersion measurement. In this annual report, an approach to ways to estimate the dispersivities of reservoir rocks from well logs is presented. From a series of rock property measurements and dispersion tests the following studies have been made: A measure of rock heterogeneity is developed by using the effluent concentration at one pore volume injection in a matched viscosity miscible displacement. By this approach, a heterogeneity factor is determined from the measured S-shaped dispersion curve. The parameter f in the Coats-Smith capacitance model is redefined as the dispersion fraction f{sub d} (or mechanical mixing fraction). At the f{sub d} pore volume injection, the dynamic miscible displacement efficiency reaches maximum. Reflected on the dispersion curve, this number corresponds to the peak of the first derivative of concentration. With the concept of dispersion fraction, a unique solution to the capacitance model is obtained, and then an equivalent dispersivity is defined. Through experimental data on Berea and Brown sandstone samples, it has been found that the equivalent dispersivity is an exponential function of the heterogeneity factor and can be used as a reservoir characteristic. Through a key parameter of tortuosity, dispersivity is related to rock petrophysical properties. This semi-theoretical relationship forms the basis for determining dispersivities from well logs. The approach is validated through experimental studies on Berea and Brown sandstone samples. It has been found that the equivalent dispersivity is an exponential function of the heterogeneity factor and can be used as a reservoir characteristic.

Menzie, D.E.

1992-04-01

163

Correlation structure of flow variables for steady flow toward a well with application to highly anisotropic heterogeneous formations  

NASA Astrophysics Data System (ADS)

The study, a continuation of that of Indelman et al. [1996], aims at deriving the second-order moments of flow variables such as hydraulic head, its gradient, and the specific discharge for steady flow toward a fully penetrating well in a confined heterogeneous aquifer. The log conductivity Y=ln K is modeled as a three-dimensional stationary function of Gaussian correlation of anisotropy ratio e. By using first-order approximations in ?2Y and e, we derive the variance and the vertical integral scale of the piezometric head H, of its radial gradient Er and of the radial component of the specific discharge qr. Owing to the nonuniformity of the average flow, these quantities are functions of the distance from the well. It is shown that the variances of the head ?2H and of its gradient ?2Er, as well as the crossvariance ?E,Y between Er and Y vanish at the well, whereas the discharge variance ?2qr tends to the product between the log conductivity variance ?2Y and the squared mean discharge 2. This behavior pertains to a stratified formation surrounding the well. Far from the well (?75 horizontal Y integral scales I) the head variance approaches a constant value. For r ? 10I the moments ?2Er, ?2qr and ?ErY tend to the corresponding values for uniform flow but with the local mean head gradient replacing the constant one. The head vertical integral scale grows indefinitely with r, whereas the vertical integral scale of the flux is larger by one log conductivity vertical scale than the one prevailing in uniform flow. This latter property is explained by the presence of the source line, which increases the correlations in the vertical direction. The present results may be used in identifying the log conductivity statistical parameters from flowmeter velocity measurements in piezometers surrounding pumping or injecting wells.

Fiori, A.; Indelman, P.; Dagan, G.

1998-04-01

164

A Study of the Geology of the Rocks of the Huntington Formation in the Izee and Olds Ferry Terrains of the Blue Mountains Region  

NSDL National Science Digital Library

This winning entry in the museum's Young Naturalist Awards 1999 by Matthew, a 17 year old student from Idaho, takes a look at the geology of the rocks of the Huntington Formation. His essay discusses the hypothetical series of events that explains how the Izee and Olds Ferry terrains were formed over hundreds of millions of years, the 10 rock specimens he collected there and the metamorphoses they have each undergone.

165

Geologic and hydrologic data for the Rustler Formation near the Waste Isolation Pilot Plant, southeastern New Mexico  

USGS Publications Warehouse

The U.S. Geological Survey is investigating the geohydrology in the vicinity of the Waste Isolation Pilot Plant in southeastern New Mexico. Data presented were compiled in support of a regional groundwater flow model. The data include water level measurements obtained from the U.S. Geological Survey 's Groundwater Site-Inventory and OMNIANA data bases and stratigraphic information interpreted from commercial geophysical logs. (USGS)

Richey, Steven F.

1989-01-01

166

INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO  

SciTech Connect

The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 1 of the project has been reservoir description and characterization. This effort has included four tasks: (1) geoscientific reservoir characterization, (2) the study of rock-fluid interactions, (3) petrophysical and engineering characterization and (4) data integration. This work was scheduled for completion in Year 1. Overall, the project work is on schedule. Geoscientific reservoir characterization is essentially completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions has been initiated. Observations regarding the diagenetic processes influencing pore system development and heterogeneity in these reef and shoal reservoirs have been made. Petrophysical and engineering property characterization is progressing. Data on reservoir production rate and pressure history at Appleton and Vocation Fields have been tabulated, and porosity data from core analysis has been correlated with porosity as observed from well log response. Data integration is on schedule, in that, the geological, geophysical, petrophysical and engineering data collected to date for Appleton and Vocation Fields have been compiled into a fieldwide digital database for reservoir characterization, modeling and simulation for the reef and carbonate shoal reservoirs for each of these fields.

Ernest A. Mancini

2001-09-14

167

Identification of discharge zones and quantification of contaminant mass discharges into a local stream from a landfill in a heterogeneous geologic setting  

NASA Astrophysics Data System (ADS)

SummaryContaminants from Risby Landfill (Denmark) are expected to leach through the underlying geologic strata and eventually reach the local Risby Stream. Identification of the groundwater discharge zone was conducted systematically by an array of methods including studies on site geology and hydrogeology, ground- and surface water flows and landfill leachate tracing from April 2009 to December 2010. Chemical profiling by driven wells and gradients in streambed temperatures was an efficient method to identify the contaminant discharge area. A considerable variation of leachate indicators, redox parameters and xenobiotic organic compounds were revealed in this area because of a complex geological setting with clay till (interbedded sand lenses) and deposits of sand and peat. Concentrations of leachate indicators decreased from the landfill to the stream, implying attenuation processes. Xenobiotic organic compounds were mainly phenoxy acid herbicides, while petroleum hydrocarbons and chlorinated solvents were found at very few boreholes. Findings of putative metabolites of phenoxy acid herbicides suggest degradation under the anaerobic conditions, which dominated inside and beneath the landfill. The groundwater discharge was quantified by two methods: direct collection of discharged groundwater by seepage meters and calculations from measurement of streambed temperature gradients. The landfill impacted the stream seasonally during dry periods when concentrations in the stream reached groundwater concentration levels. A comparison between mass balance for selected stream stretches and upscaled measurements of the contaminant discharge from groundwater into the stream indicated that only a small part of the actual contaminant discharge of the stream could be explained by the inflowing contaminant discharge from groundwater. Surface runoff and seepage from ponds along the stream impacted by landfill interflow may be important pathways as well. The placement of Risby Landfill near a stream and the complex source and geology causing a large spatial variability of leachate compounds are typical for landfill sites so the approaches and findings from Risby Landfill can be applied to other landfill sites. The study highlights that landfills may pose a risk to surface waters and future studies should be directed towards evaluation of both chemical and ecological risk.

Milosevic, N.; Thomsen, N. I.; Juhler, R. K.; Albrechtsen, H.-J.; Bjerg, P. L.

2012-06-01

168

Geology and Radiometry of Chalkidiki.  

National Technical Information Service (NTIS)

A brief geological description of Chalkidiki (Greece) is given followed by car-borne-scintillometer (CBS) survey results showing that granitic rocks in Central and Eastern Chalkidiki constitute the most promising geological formations for uranium minerali...

D. G. Minatidis

1980-01-01

169

A study of the relationship of geological formation to the NORM. Quarterly technical progress report, April 1--June 30, 1995  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. The approach to this problem involves development of NORM prediction capabilities based on the geological environment. During the third quarter of this project, emphasis was placed on three tasks; laboratory procedural development, continuance of preliminary geologic data acquisition, and the beginning of field testing of non-produced water sites. Laboratory procedures development included applications of pertinent EPA/Standard Methods, as well as continuing orientation with respect to radiation safety procedures and practices. In terms of progress on the geologic aspects of the project, compilation of relevant well data for the study area is in progress.

Bursh, T.P.; Chriss, D.

1995-07-18

170

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico-stratigraphic hierarchy and cycle stacking facies distribution, and interwell-scale heterogeneity: Grayburg Formation, New Mexico. Final report  

SciTech Connect

The Grayburg Formation (middle Guadalupian) is a major producing interval in the Permian Basin and has yielded more than 2.5 billion barrels of oil in West Texas. Grayburg reservoirs have produced, on average, less than 30 percent of their original oil in place and are undergoing secondary and tertiary recovery. Efficient design of such enhanced recovery programs dictates improved geological models to better understand and predict reservoir heterogeneity imposed by depositional and diagenetic controls. The Grayburg records mixed carbonate-siliciclastic sedimentation on shallow-water platforms that rimmed the Delaware and Midland Basins. Grayburg outcrops in the Guadalupe and Brokeoff Mountains region on the northwest margin of the Delaware Basin present an opportunity to construct a detailed, three-dimensional image of the stratigraphic and facies architecture. This model can be applied towards improved description and characterization of heterogeneity in analogous Grayburg reservoirs. Four orders of stratigraphic hierarchy are recognized in the Grayburg Formation. The Grayburg represents a long-term composite sequence composed of four high-frequency sequences (HFS 1-4). Each HFS contains several composite cycles comprising two or more cycles that define intermediate-scale transgressive-regressive successions. Cycles are the smallest scale upward-shoaling vertical facies successions that can be recognized and correlated across various facies tracts. Cycles thus form the basis for establishing the detailed chronostratigraphic correlations needed to delineate facies heterogeneity.

Barnaby, R.J.; Ward, W.B.; Jennings, J.W. Jr.

1997-06-01

171

Geology of Brunei deltas, exploration status updated  

SciTech Connect

This article summarizes the petroleum geology of Negara Brunei Darussalam, the smallest but oil and gas richest country in Northwest Borneo. The paper describes the exploration history, Brunei geology, structural geology, main hydrocarbon reservoirs, seals, formation pressures, and current exploration.

Schreurs, J. [Brunei Shell Petroleum Co.Sdn. Bhd., Seria (Brunei Darussalam)

1997-08-04

172

Geology of the Early Arikareean sharps formation on the Pine Ridge Indian Reservation and surrounding areas of South Dakota and Nebraska.  

PubMed

Based on geologic mapping, measured sections, and lithologic correlations, the local features of the upper and lower type areas of the Early Arikareean (30.8-20.6 million years ago) Sharps Formation are revised and correlated. The Sharps Formation above the basal Rockyford Member is divided into two members of distinct lithotypes. The upper 233 feet of massive siltstones and sandy siltstones is named the Gooseneck Road Member. The middle member, 161 feet of eolian volcaniclastic siltstones with fluvially reworked volcaniclastic lenses and sandy siltstone sheets, is named the Wolff Camp Member. An ashey zone at the base of the Sharps Formation is described and defined as the Rockyford Ash Zone (RAZ) in the same stratigraphic position as the Nonpareil Ash Zone (NPAZ) in Nebraska. Widespread marker beds of fresh water limestones at 130 feet above the base of the Sharps Formation and a widespread reddish-brown clayey siltstone at 165 feet above the base of the Sharps Formation are described. The Brown Siltstone Beds of Nebraska are shown to be a southern correlative of the Wolff Camp Member and the Rockyford Member of the Sharps Formation. Early attempts to correlate strata in the Great Plains were slow in developing. Recognition of the implications of the paleomagnetic and lithologic correlations of this paper will provide an added datum assisting researchers in future biostratigraphic studies. Based on similar lithologies, the Sharps Formation, currently assigned to the Arikaree Group, should be reassigned to the White River Group. PMID:23110098

McConnell, Thomas H; Dibenedetto, Joseph N

2012-01-01

173

Newly Discovered Ophiolite Scrap in the Hartland Formation of Midtown Charles Merguerian, Geology Department, 114 Hofstra University, Hempstead, NY 11549  

E-print Network

, highly deformed ellipsoidal serpentinite body that has been uncovered during recent excavation of a deep February 2005 we had four opportunities to examine the bedrock geology of a large construction excavation, west of Sixth Avenue and was ultimately excavated to a depth of ~60' below street level (Figure 1

Merguerian, Charles

174

Non-Darcian flow in low-permeability media: key issues related to geological disposal of high-level nuclear waste in shale formations  

NASA Astrophysics Data System (ADS)

In clay or other low-permeability media, water flow becomes non-Darcian and characterized by the non-linear relationship between water flux and hydraulic gradient. This work is devoted to addressing a number of key issues related to geological disposal of high-level nuclear waste in clay/shale formations. It is demonstrated that water flow velocity in the damaged zone (often considered as a potential preferential advection paths in a repository) surrounding the tunnel is extremely small, as a result of non-Darcian flow behavior, such that solute transport is dominated by diffusion, rather than advection. The finding is also consistent with the often-observed existence of persistent abnormal pressures in shale formations. While relative permeability is the key parameter for modeling the unsaturated flow process, without incorporating non-Darcian flow behavior, significant errors can occur in the determination of relative permeability values from traditional measurement methods. An approach for dealing with temperature impact on non-Darcian flow and a formulation to calculate non-Darcian water flux in an anisotropic medium are presented, taking into consideration that a geological repository is subject to temperature evolution in the near field as a result of heat generated by nuclear waste, and that shale formations are generally anisotropic.

Liu, Hui-Hai

2014-05-01

175

Advances in Planetary Geology  

NASA Technical Reports Server (NTRS)

Advances in Planetary Geology is a new series intended to serve the planetary geology community with a form for quick and thorough communications. There are no set lists of acceptable topics or formats, and submitted manuscripts will not undergo a formal review. All submissions should be in a camera ready form, preferably spaced, and submitted to the editor.

Woronow, A. (editor)

1982-01-01

176

Formation of nitro-PAHs from the heterogeneous reaction of ambient particle-bound PAHs with N2O5/NO3/NO2  

PubMed Central

Reactions of ambient particles collected from four sites within the Los Angeles, CA air basin and Beijing, China with a mixture of N2O5, NO2, and NO3 radicals were studied in an environmental chamber at ambient pressure and temperature. Exposures in the chamber system resulted in the degradation of particle-bound PAHs and formation of molecular weight (mw) 247 nitropyrenes (NPYs) and nitrofluoranthenes (NFLs), mw 273 nitrotriphenylenes (NTPs), nitrobenz[a]anthracenes (NBaAs), and nitrochrysene (NCHR), and mw 297 nitrobenzo[a]pyrene (NBaP). The distinct isomer distributions resulting from exposure of filter-adsorbed deuterated fluoranthene to N2O5/NO3/NO2 and that collected from the chamber gas-phase suggest that formation of NFLs in ambient particles did not occur by NO3 radical-initiated reaction, but from reaction of N2O5, presumably subsequent to its surface adsorption. Accordingly, isomers known to result from gas-phase radical-initiated reactions of parent PAHs, such as 2-NFL and 2- and 4-NPY, were not enhanced from the exposure of ambient particulate matter to N2O5/NO3/NO2. The reactivity of ambient particles toward nitration by N2O5/NO3/NO2, defined by relative 1-NPY formation, varied significantly, with the relative amounts of freshly emitted particles versus aged particles (particles that had undergone atmospheric chemical processing) affecting the reactivity of particle-bound PAHs toward heterogeneous nitration. Analyses of unexposed ambient samples suggested that, in nighttime samples where NO3 radical-initiated chemistry had occurred, heterogeneous formation of 1-NPY on ambient particles may have contributed to the ambient 1-NPY concentrations at downwind receptor sites. These results, together with observations that 2-NFL is consistently the dominant particle-bound nitro-PAH measured in ambient atmospheres, suggest that for PAHs that exist in both the gas- and particle-phase, the heterogeneous formation of particle-bound nitro-PAHs is a minor formation route compared to gas-phase formation. PMID:23865889

Zimmermann, Kathryn; Jariyasopit, Narumol; Massey Simonich, Staci L.; Tao, Shu; Atkinson, Roger; Arey, Janet

2014-01-01

177

Methods and apparatus for measurement of the resistivity of geological formations from within cased wells in presence of acoustic and magnetic energy sources  

DOEpatents

Methods and apparatus are provided for measuring the acoustically modulated electronic properties of geological formations and cement layers adjacent to cased boreholes. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. Voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the leakage current conducted into formation in the vicinity of those electrodes. Simultaneously subjecting the casing and formation to an acoustic source acoustically modulates the leakage current measured thereby providing a measure of the acoustically modulated electronic properties of the adjacent formation. Similarly, methods and apparatus are also described which measure the leakage current into formation while simultaneously subjecting the casing to an applied magnetic field which therefore allows measurement of the magnetically modulated electronic properties of the casing and the adjacent formation.

Vail, III, William B. (Bothell, WA)

1991-01-01

178

Formation of nitro-PAHs from the heterogeneous reaction of ambient particle-bound PAHs with NO3/N2O5  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) and their nitrated derivatives (nitro-PAHs) have been shown to be mutagenic in bacterial and mammalian assays and are classified as probable human carcinogens. Semi-volatile PAHs partition between the gas and particulate phases, depending on their liquid-phase vapor pressures and ambient temperatures. These PAHs have been extensively measured in ambient particulate matter and can ultimately undergo long-range transport from source regions (e.g., China to the western USA) (1). During transport these particle-bound PAHs may undergo reaction with NO3/N2O5 to form nitro-PAH derivatives. Previous studies of heterogeneous nitration of PAHs have used particles composed of graphite, diesel soot, and wood smoke (2-4). This study investigates the heterogeneous formation of nitro-PAHs from ambient particle-bound PAHs from Beijing, China and sites located within the Los Angeles air basin. These ambient particle samples, along with filters coated with isotopically labeled PAHs, were exposed to a mix of NO2/NO3/N2O5 in a 7000 L Teflon chamber, with analysis focused on the heterogeneous formation of molecular weight 247 and 273 nitro-PAHs. The heterogeneous formation of certain nitro-PAHs (including1-nitropyrene and 1- and 2-nitrotriphenylene) was observed for some, but not all, ambient samples. Formation of nitro-PAHs typically formed through gas-phase reactions (2-nitrofluoranthene and 2-nitropyrene) was not observed. The effect of particle age and local photochemical conditions during sampling on the degree of nitration in environmental chamber reactions, as well as ambient implications, will be presented. 1. Primbs, T.; Simonich, S.; Schmedding, D.; Wilson, G.; Jaffe, D.; Takami, A.; Kato, S.; Hatakeyama, S.; Kajii, Y. Environ. Sci. Technol. 2007, 41, 3551-3558. 2. Esteve, W.; Budzinski, H.; Villenave, E. Atmospheric Environment 2004, 38, 6063-6072. 3. Nguyen, M.; Bedjanian, Y.; Guilloteau, A. Journal of Atmospheric Chemistry 2009, 62, 139-150. 4. Kamens, R. M.; Zhi-Hua, F.; Yao, Y.; Chen, D.; Chen, S.; Vartiainen, M. Chemosphere 1994, 28, 1623-1632.

Zimmermann, K.; Jariyasopit, N.; Simonich, S. L.; Atkinson, R.; Arey, J.

2012-12-01

179

Devil's Tower Geology  

NSDL National Science Digital Library

This site from the National Park Service briefly addresses the geology of Devil's Tower. The evolution of various theories on the formation of the tower are discussed. A slide show of the emplacement of the tower is also available.

National Park Service (NPS)

180

A noniterative technqiue for the direct implementation of well bore boundary conditions in three-dimensional heterogeneous formations  

Microsoft Academic Search

A noniterative algorithm for handling prescribed well bore boundary conditions while pumping or injecting fluid in a three-dimensional heterogeneous aquifer is described. The algorithm is formulated by superimposing conductive one-dimensional line elements representing the well screen onto the three-dimensional matrix elements representing the aquifer. Storage in the well casing is also naturally accommodated by the superposition of the line elements.

E. A. Sudicky; A. J. A. Unger; S. Lacombe

1995-01-01

181

Modeling Geologic Time  

NSDL National Science Digital Library

In this activity students convert major events in Earth history from years before present into scale distances. After a list of events and their scale distances have been formulated, students construct a geologic time scale on 5 meters of adding machine paper, beginning with the formation of the Earth. Students will investigate change through geologic time; design, construct and interpret a model of geologic time; relate major events in Earth history to the geologic time scale; and compare and relate the span of Earth history to events of historical time and of the human lifetime. Some sample events and their approximate relative ages are included.

Firebaugh, James

182

Inversion of synthetic geodetic data for dip-slip faults: clues to the effects of lateral heterogeneities and data distribution in geological environments typical of the Apennines (Italy)  

NASA Astrophysics Data System (ADS)

The inversion of geodetic data to obtain earthquake parameters is often performed by assuming that the medium is isotropic, elastic and either homogeneous or layered. The layered medium often offers the best estimate of the structure of the crust; however, predicted displacements and observed data may differ beyond the measurement errors. The slip distribution on the fault plane is usually obtained by dividing the best uniform slipping fault into an arbitrarily large number of subfaults and minimizing a cost function that includes a smoothness (Laplacian) term and a data misfit term. The smoothing factor controls the trade-off between the smoothness and the goodness-of-fit. The main focus of this work is the determination and effect of the smoothing parameter. We conducted several inversion tests of noiseless synthetic surface displacement due to faults embedded in media with properties consistent with the geology of the Central Apennines (Italy), where the 2009 April 6, L'Aquila earthquake occurred. We used the following three-step procedure: (i) global optimization with no smoothness constraint for a fault divided into a small number of equally sized equal-rake subfaults; (ii) selection of the best fault parameters using information criteria and (iii) evaluation of the slip amplitude distribution on an expanded fault after choosing the smoothing factor from trade-off curves or from cross-validation for different numbers of subfaults. We show that all of the fault features obtained by the inversion procedure, including the slip distribution, agree with those (`true') used in the forward modelling when the data cover the majority of the displacement field. Notable departures from the true slip distribution occur when a suboptimal smoothing factor (obtained from the trade-off curves or cross-validation) is used. If different crustal stratifications are used in the inversions, the best results are obtained for the stratification that is the closest to the true crustal structure. When we use more realistic GPS distributions, prominent spurious slip patches can be obtained. Modellers should use synthetic tests and sensitivity analyses as an initial step in the data inversion for source parameters.

Amoruso, A.; Barba, S.; Crescentini, L.; Megna, A.

2013-02-01

183

Physical Characteristics, Geologic Setting, and Possible Formation Processes of Spring Deposits on Mars Based on Terrestrial Analogs  

NASA Technical Reports Server (NTRS)

Spring formation is a predicted consequence of the interaction of former Martian aquifers with structures common to Mars, including basin margins, Tharsis structures, and other structural deformation characteristics. The arid environment and high abundance of water soluble compounds in the crust will have likewise encouraged spring deposit formation at spring sites. Such spring deposits may be recognized from morphological criteria if the characteristics of formation and preservation are understood. An important first step in the current Mars exploration strategy [10] is the detection of sites where there is evidence for past or present near-surface water on Mars. This study evaluates the large-scale morphology of spring deposits and the physical processes of their formation, growth, and evolution in terms that relate to (1) their identification in image data, (2) their formation, evolution, and preservation in the environment of Mars, and (3) their potential as sites of long-term or late stage shallow groundwater emergence at the surface of Mars.

Crumpler, L. S.

2003-01-01

184

IgG particle formation during filling pump operation: A case study of heterogeneous nucleation on stainless steel nanoparticles  

Microsoft Academic Search

This study investigated factors associated with vial filling with a positive displacement piston pump leading to formation of protein particles in a formulation of an IgG. We hypothesized that nanoparticles shed from the pump's solution-contact surfaces nucleated protein aggregation and particle formation. Vials of IgG formulation filled at a clinical manufacturing site contained a few visible particles and about 100,000

Anil K. Tyagi; Theodore W. Randolph; Aichun Dong; Kevin M. Maloney; CARL HITSCHERICH JR; John F. Carpenter

2009-01-01

185

Banded iron-formations of late Proterozoic age in the central eastern desert, Egypt: geology and tectonic setting.  

USGS Publications Warehouse

Iron-formation occurs as stratigraphic units within a layered andesite-basalt sequence. The sequence is metamorphosed to greenschist facies, intruded by syntectonic granodiorite and post-tectonic granite, and complexly deformed and grossly fragmented; the rocks are allochthonous along thrust faults. The iron deposits are chemical precipitates, accumulated during lulls in volcanism, apparently in an intraoceanic island-arc environment. The deposits are of the Algoma type of iron-formation.-G.J.N.

Sims, P. K.; James, H. L.

1984-01-01

186

A geological and engineering reservoir characterization of the Caballos Formation (Cretaceous), Puerto Colon field Putumayo basin, Colombia  

E-print Network

index of 38. 4; this suggests a marine-continental transition environment. Based on the vitrinite reflactance index of Iso=0. 57 percent, the Caballos Formation is considered to be mature for petroleum generation. ' The marine shale at the base... index of 38. 4; this suggests a marine-continental transition environment. Based on the vitrinite reflactance index of Iso=0. 57 percent, the Caballos Formation is considered to be mature for petroleum generation. ' The marine shale at the base...

Ruiz Castellanos, Hector

2012-06-07

187

An integrated multi-scale hydrogeological model for performance and safety assessment of French geological high level and long live radwaste disposal in clay formation  

NASA Astrophysics Data System (ADS)

A deep geological repository of high level and long live radwaste requires sound understanding of the far field and near field groundwater flow and transport properties. Andra, French National radioactive waste management Agency is developing since last 15 years, an integrated multi-scale hydrogeological model of whole Paris basin of 200'000 Km2 area (regional scale) to produce a regional flow field associated to groundwater behavior. It includes locally the Meuse / Haute Marne clay site of about 250 Km2 area in the eastern part of Paris basin that was chosen for the emplacement of a repository. Callovo-Oxfordian as host formation is a clay layer characterized by very low permeability, a mean thickness of 130 m at about 500 m depth and is embedded by calcareous formations as aquifers (Dogger and Oxfordian). The hydrogeological conceptual model is based on stratigraphic and petrophysic modeling of the Paris basin and is accounting for the sound structural, geological, hydrogeological and geochemical data in an integrated way. At Paris basin scale, the model is a multilayer system of 27 layers (hydrogeological units) from Trias to Tertiary. A refinement at local scale of the site defines 27 hydro-geological units from Trias to Portlandian within an area of 1800 Km2. Based on sound data acquisition from borehole and seismic campaigns performed by Andra, regional faults, minor and diffuse fractures are considered. A structural and petrophysical representation of the transition zone between the Paris basin scale and site scale, as well as a better handling of surface flow boundary conditions are considered. Finite element flow and transport simulator Ground Water code (GW) is used to solve for groundwater flow at steady-state in a 1.8 Million nodes model, considering current climatic conditions. The model is calibrated against about 1250 hydraulic head measurements, and results in maximum absolute hydraulic head differences of 20 meters at the regional scale and 5 meters at the local scale. The calibrated reference model includes transmissive major faults as well as structures acting as barrier to flow. Advective-dispersive age solutions are also carried out and compared to available age dates of pore water within the two main calcareous aquifers (Dogger and Oxfordian) that embed Callovo-Oxfordian host formation, to consolidate calibration of flow and to analyze internal water mixing processes and hydraulic behavior of major faults. Lifetime expectancy solutions combined with age solutions are also used to map in the 3-D space the low- and high-speed flow zones at the local scale.

Benabderrahmane, H.; Cornaton, F. J.; Kerrou, J.

2009-12-01

188

Formation of gas-phase carbonyls from heterogeneous oxidation of polyunsaturated fatty acids at the air-water interface and of the sea surface microlayer  

NASA Astrophysics Data System (ADS)

Motivated by the potential for reactive heterogeneous chemistry occurring at the ocean surface, gas-phase products were observed when a reactive sea surface microlayer (SML) component, i.e. the polyunsaturated fatty acids (PUFA) linoleic acid (LA), was exposed to gas-phase ozone at the air-seawater interface. Similar oxidation experiments were conducted with SML samples collected from two different oceanic locations, in the eastern equatorial Pacific Ocean and from the west coast of Canada. Online proton-transfer-reaction mass spectrometry (PTR-MS) University of Colorado light-emitting diode cavity-enhanced differential optical absorption spectroscopy (LED-CE-DOAS) were used to detect oxygenated gas-phase products from the ozonolysis reactions. The LA studies indicate that oxidation of a PUFA monolayer on seawater gives rise to prompt and efficient formation of gas-phase aldehydes. The products are formed via the decomposition of primary ozonides which form upon the initial reaction of ozone with the carbon-carbon double bonds in the PUFA molecules. In addition, two highly reactive dicarbonyls, malondialdehyde (MDA) and glyoxal, were also generated, likely as secondary products. Specific yields relative to reactant loss were 78%, 29%, 4% and < 1% for n-hexanal, 3-nonenal, MDA and glyoxal, respectively, where the yields for MDA and glyoxal are likely lower limits. Heterogeneous oxidation of SML samples confirm for the first time that similar carbonyl products are formed via ozonolysis of environmental samples.

Zhou, S.; Gonzalez, L.; Leithead, A.; Finewax, Z.; Thalman, R.; Vlasenko, A.; Vagle, S.; Miller, L. A.; Li, S.-M.; Bureekul, S.; Furutani, H.; Uematsu, M.; Volkamer, R.; Abbatt, J.

2014-02-01

189

Uncertainties caused by the geological structure in hydrogeological modeling: Stochastic simulation of a heterogeneous glacial structure with emphasize on stationarity issues and the incorporation of borehole- and geophysical data.  

NASA Astrophysics Data System (ADS)

The heterogeneity of the geological structure causes uncertainties in hydrogeological investigations of groundwater flow and contaminant transport. Traditionally the best comprehensive knowledge is combined in order to create one model of the subsurface structure, often based on subjective interpretations and sparse data availability. Stochastic simulation methods address this problem by generating an ensemble of realizations of the geology, all of them equally plausible, because they honor available data and follow predefined geometrical attributes such as proportions and mean lengths. In this study the geostatistical software T-ProGS is utilized to simulate an ensemble of realizations for a binary (sand/clay) hydrofacies model in the Norsminde catchment, eastern Jutland, Denmark. Categorized borehole data and geophysical data (SkyTEM) indicate a variation of sand proportion within the model area. Therefore the model domain is subdivided into three independent and statistically stationary sub-model domains of different sand proportions and mean lengths. The sand proportion in the SkyTEM data depends on a cut-off value, separating the dataset into sand and clay. This cut-off value is manually calibrated by assuming the smallest deviation between the sand proportions in the borehole- and in the SkyTEM data in areas with a high sample density. The calibration yields an overall sand proportion of 23% with a cut-off value of 46 ?m. The stochastic simulations are conditioned against the available datasets with hard and soft conditioning. The category probabilities for the SkyTEM dataset are derived from a histogram approach, where resistivity is associated with corresponding lithology from the categorized borehole data. The boreholes are grouped in four quality groups, which are associated with trust scores, allowing soft conditioning. In total, 30 realizations are simulated for each sub-domain and for the entire domain. Ten simulations are selected by favoring minimal deviations between simulated and desired sand proportions. The simulations for the individual sub-domains produce more accurate results with respect to the sand proportion than the case where the entire domain is simulated altogether. However the variation in mean lengths in the sub-domains is not simulated correctly. Moreover, a split sample test indicates a significant gain in simulation accuracy, if SkyTEM data are incorporated. If only borehole data are used for conditioning, it simulates only 25% of the sand cells correctly.

Koch, Julian; He, Xin; Refsgaard, Jens C.; Jensen, Karsten H.

2013-04-01

190

Electrofusion between heterogeneous-sized mammalian cells in a pellet: potential applications in drug delivery and hybridoma formation.  

PubMed Central

High-efficiency electrofusion between cells of different sizes was achieved by application of fusing electric pulses to cells in centrifuged pellets. Larger target cells (Chinese hamster ovary or L1210 cells) were stacked among smaller human erythrocytes or erythrocyte ghosts by sequential centrifugation at 700 g to form five-tier pellets in a specially designed centrifugation-electrofusion chamber. The membranes of erythrocytes and ghost were labeled with fluorescent membrane dye (1,1' dioctadecyl-3,3,3'3'-tetramethylindocarbocyanine (Dil)), and the contents of ghosts were loaded with water-soluble fluorescent dye (42-kDa fluorescein isothiocyanate dextran (FITC-dextran)), to monitor heterogeneous cell fusion. Fusion efficiency was assayed by the extent of either membrane dye mixing or contents (FITC-dextran) mixing with target cells. Four rectangular electric pulses at 300 V and 80 microseconds each were found to give the optimal fusion results of approximately 80% heterogeneous fusion by the content-mixing assay and approximately 95% by the membrane-dye-mixing assay. Cell viability remained greater than 80% after electrofusion. Because of the electric breakdown of cell membranes at the beginning of the pulse, the pellet resistance and hence the partial voltage across the pellet reduced rapidly during the remaining pulse time. This voltage redistribution favored the survival of fused cells. The limited colloidal-osmotic swelling of cells in pellets enhanced cell-cell contact and increased the pellet resistance after each pulse. As a result, the partial voltage across the pellet was restored when the next pulse was applied. This redistribution of pulse voltage in the pellet system permitted the breakdown of cell membranes at a lower applied voltage threshold than that required for electrofusion of cells in suspension or in dielectrophoretic cell chains. The cell viability and soluble dye retention within cells (FITC-dextran) remained at the same high levels for 3 h when the cells were incubated in respective culture media with serum at 37 degrees C. Viability and dye retention decreased significantly within 30 min when cells were incubated in phosphate-buffered saline without serum. The pellet technique was applied to form hybridomas by fusion of larger SP2/0 murine myelomas with smaller naive mouse lymphocytes. An optimum of 173 +/- 70 hypoxanthine aminopterin thymidine (HAT)-selected clones of the hybridomas was obtained from 40,000 SP2/0 cells and 1.5 x 10(6) lymphocytes used in each trial. This high-efficiency fusion technique may be adapted to mediate drug and gene transfer to target cells ex vivo as well as to form hybrid cells with limited cell sources. PMID:8804630

Li, L H; Hensen, M L; Zhao, Y L; Hui, S W

1996-01-01

191

Mathematical Geology.  

ERIC Educational Resources Information Center

Mathematical techniques used to solve geological problems are briefly discussed (including comments on use of geostatistics). Highlights of conferences/meetings and conference papers in mathematical geology are also provided. (JN)

Jones, Thomas A.

1983-01-01

192

Geological images  

NSDL National Science Digital Library

This site from Marli Bryant Miller, a professor at the University of Oregon, presents images of geological features from around the world. Photographs of glacial features, igneous and metamorphic rocks and processes, and structural geology are featured.

Miller, Marli B.; Oregon, University O.

193

Coupling geothermal energy capture with carbon dioxide sequestration in permeable, porous geologic formations II: Numerical modeling and preliminary results  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) sequestration in deep saline aquifers and exhausted oil fields has been widely considered as a means for reducing CO2 emissions to the atmosphere as a counter-measure to global warming. However, rather than treating CO2 as a waste fluid in need of permanent disposal, it could additionally be used as a working fluid in geothermal energy capture as its thermodynamic properties suggest it transfers heat more efficiently than water. Therefore, utilizing CO2 may permit more widespread implementation of geothermal power systems. Here, we present numerical modeling results of coupled CO2 injection into a brine and heat transfer in geothermal reservoirs under conditions relevant for both CO2 sequestration and geothermal electricity generation. In particular, we examine subsurface flow and heating of the sequestered CO2, cooling of the geothermal reservoir, and changes in pore-fluid pressures under a variety of generalized CO2 injection and production scenarios and reservoir characteristics. While additional research is required, modeling results at present suggest that geologic reservoirs with CO2 as the heat mining fluid would be viable geothermal energy sources for electric power production for decades, potentially even in regions with relatively low geothermal temperatures and heat flow rates.

Randolph, J. B.; Saar, M. O.

2009-12-01

194

INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO  

SciTech Connect

The University of Alabama, in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company, has undertaken an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary goal of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. Geoscientific reservoir property, geophysical seismic attribute, petrophysical property, and engineering property characterization has shown that reef (thrombolite) and shoal reservoir lithofacies developed on the flanks of high-relief crystalline basement paleohighs (Vocation Field example) and on the crest and flanks of low-relief crystalline basement paleohighs (Appleton Field example). The reef thrombolite lithofacies have higher reservoir quality than the shoal lithofacies due to overall higher permeabilities and greater interconnectivity. Thrombolite dolostone flow units, which are dominated by dolomite intercrystalline and vuggy pores, are characterized by a pore system comprised of a higher percentage of large-sized pores and larger pore throats. Rock-fluid interactions (diagenesis) studies have shown that although the primary control on reservoir architecture and geographic distribution of Smackover reservoirs is the fabric and texture of the depositional lithofacies, diagenesis (chiefly dolomitization) is a significant factor that preserves and enhances reservoir quality. The evaporative pumping mechanism is favored to explain the dolomitization of the thrombolite doloboundstone and dolostone reservoir flow units at Appleton and Vocation Fields. Geologic modeling, reservoir simulation, and the testing and applying the resulting integrated geologic-engineering models have shown that little oil remains to be recovered at Appleton Field and a significant amount of oil remains to be recovered at Vocation Field through a strategic infill drilling program. The drive mechanisms for primary production in Appleton and Vocation Fields remain effective; therefore, the initiation of a pressure maintenance program or enhanced recovery project is not required at this time. The integrated geologic-engineering model developed for a low-relief paleohigh (Appleton Field) was tested for three scenarios involving the variables of present-day structural elevation and the presence/absence of potential reef thrombolite lithofacies. In each case, the predictions based upon the model were correct. From this modeling, the characteristics of the ideal prospect in the basement ridge play include a low-relief paleohigh associated with dendroidal/chaotic thrombolite doloboundstone and dolostone that has sufficient present-day structural relief so that these carbonates rest above the oil-water contact. Such a prospect was identified from the modeling, and it is located northwest of well Permit No. 3854B (Appleton Field) and south of well No. Permit No.11030B (Northwest Appleton Field).

Ernest A. Mancini

2004-02-25

195

The Relationship of Dynamical Heterogeneity to the Adam-Gibbs and Random First-Order Transition Theories of Glass Formation  

NASA Astrophysics Data System (ADS)

We examine measures of dynamical heterogeneity for a bead-spring polymer melt and test how these scales compare with the scales hypothesized by the Adam and Gibbs (AG) and random first-order transition (RFOT) theories. We show that the time scale of the high-mobility clusters and strings is associated with a diffusive time scale, while the low-mobility particles' time scale relates to a structural relaxation time. The difference of the characteristic times naturally explains the decoupling of diffusion and structural relaxation time scales. We examine the appropriateness of identifying the size scales of mobile particle clusters or strings with the size of cooperatively rearranging regions (CRR) in the AG and RFOT theories. We find that the string size appears to be the most consistent measure of CRR for both the AG and RFOT models. Identifying strings or clusters with the``mosaic'' length of the RFOT model relaxes the conventional assumption that the``entropic droplet'' are compact. We also confirm the validity of the entropy formulation of the AG theory, constraining the exponent values of the RFOT theory. This constraint, together with the analysis of size scales, enables us to estimate the characteristic exponents of RFOT.

Starr, Francis; Douglas, Jack; Sastry, Srikanth

2013-03-01

196

Structural Geology  

NSDL National Science Digital Library

Created by the University of Nebraska-Lincoln, this site describes the basics of structural geology with text and images. The page includes the discussion of stress, strain, strike and dip, faults, folds, mountain building, erosion, economic geology, and environmental geology. This is a nice introduction to the basic topics in geology. Images from the field help to enhance the topics on the site. Instructors can use this resource to help create or simply enhance their curriculum.

2009-05-21

197

Oahu Geology Field Exercises  

NSDL National Science Digital Library

Three field guides are available to sites of geologic interest on Oahu. One is a visit to a landslide occurring in a neighborhood; another focuses on developing observational skills and determining the sequence of geologic events evident in a stratigraphic section; a third examines features associated with formation of a volcanic tuff ring. The worksheets are designed for teachers to implement as-is or modify for their classes.

198

Geological Time  

NSDL National Science Digital Library

"Why do engineers need to know about geologic time?" That question is answered in this resource from the University of Saskatchewan's Department of Civil and Geological Engineering. Provided here is a discussion of the concepts of geological time; relative dating methods, such as correlation; and absolute dating methods, such as radiometric methods. Diagrams and charts are included to demonstrate these complex concepts.

2008-04-17

199

Geological SciencesGeological Sciences Geological EngineeringGeological Engineering  

E-print Network

Geological Engineering Applied Science Faculty Geology is the study of the Earth, its rocks, minerals Faculty and the Applied Science (Engineering) Faculty with various career path options. Geological engineers apply earth science principles to find and extract the world's energy and mineral wealth, to help

Ellis, Randy

200

New marine geology center  

NASA Astrophysics Data System (ADS)

Marine geologists at Dalhousie University in Halifax, Nova Scotia, have created a new Center for Marine Geology. The formation of the center is part of a university-wide effort to extend interests in marine research in all directions, Director James M. Hall said. The center, formed in April, will be a focus for the expansion of research in marine geology, for the development of marine instrumentation, for the expansion of advanced training of Third World geologists in marine geology, and for the university's interaction with the petroleum industry involved in a major play in the areas off the eastern Canadian shore, Hall said.

201

The geology, carbonaceous materials, and origin of the epigenetic uranium deposits in the Tertiary Sespe Formation in Ventura County, California  

SciTech Connect

Uranium deposits have been known in western Ventura County, California, since about 1959. These epigenetic uranium deposits are found in and are probably derived from the Tertiary Sespe Formation, which is of continental origin. The sandstone-filled paleochannels served as ground-water conduits that carried uranium-bearing solutions to the depositional site. The uranium mineralization took place when the humate was deposited (perhaps near the seashore where terrestrial and marine interacted) or perhaps shortly thereafter.

Dickinson, K.A.; Leventhal, J.S.

1988-01-01

202

Geological and geochemical controls on the formation and distribution of supergiant gas fields in the Russian sedimentary basins  

SciTech Connect

The West Siberian, Barents Sea and Northern Caspian sedimentary basins are the most prolific Russian gas producing regions and include 15 supergiant gas fields each of them content identified gas reserves between 1 x 10[sup 12] m[sup 3] to 11 x 10[sup 12] m[sup 3]. They are Urengoi, Yarnburg, Bovanenkov, Zapoljarnoye, Medvezhie, Charasavey, Kruzenshtern, N.Urengoi, S.Tambey, S.Russkoye, Rusanov, Shtockmanov, Lunin, Astrachan and Orenburg. The gas reserves in these basins exceed 70 x 10[sup 12] m[sup 3] and about 65% of them concentrated in supergiant fields. Among the geological prerequisites for largest gas accumulations note big size of trap (Urengoi 40x300 km[sup 2]; Astrachan l80x200 km[sup 2]), anticline type of tectonic structure (swell, megaswell, dome, arch) with amplitude from 110 m to 800 in. These tectonic structure were active long time include the latest period. The main gas productive reservoirs are slightly consulted non-marine sandstones of Cenomanian or Middle Jurassic ages (West Siberia and Barents Sea) or Middle Carboniferous reef carbonate buildups (Northern Caspian basin). The next geochemical parameters controlled of the gas accumulation histories: (1) West Siberia and Barents Sea regions gas genetically connect with dispersed or concentrated non-marine coal type kerogen distributed into productive complex under lower maturity conditions (before or early oil window zone). This is dry gas almost pure methane with [delta][sup 13] C[sub 1] between -44,40[per thousand]. In this case we observe widely distributed mainly sandstones reservoirs at same time gas source rocks also; (2) the Northern Caspian basin found supergiant wet gas-condensate accumulations into local distributed reef carbonate buildups. Gas source rocks is marine kerogen type II, which has a low concentration in marlaceous facies. It is gas high maturity zone.

Lopatin, N. (VNIIgeosystem, Moscow (Russian Federation))

1996-01-01

203

Geological and geochemical controls on the formation and distribution of supergiant gas fields in the Russian sedimentary basins  

SciTech Connect

The West Siberian, Barents Sea and Northern Caspian sedimentary basins are the most prolific Russian gas producing regions and include 15 supergiant gas fields each of them content identified gas reserves between 1 x 10{sup 12} m{sup 3} to 11 x 10{sup 12} m{sup 3}. They are Urengoi, Yarnburg, Bovanenkov, Zapoljarnoye, Medvezhie, Charasavey, Kruzenshtern, N.Urengoi, S.Tambey, S.Russkoye, Rusanov, Shtockmanov, Lunin, Astrachan and Orenburg. The gas reserves in these basins exceed 70 x 10{sup 12} m{sup 3} and about 65% of them concentrated in supergiant fields. Among the geological prerequisites for largest gas accumulations note big size of trap (Urengoi 40x300 km{sup 2}; Astrachan l80x200 km{sup 2}), anticline type of tectonic structure (swell, megaswell, dome, arch) with amplitude from 110 m to 800 in. These tectonic structure were active long time include the latest period. The main gas productive reservoirs are slightly consulted non-marine sandstones of Cenomanian or Middle Jurassic ages (West Siberia and Barents Sea) or Middle Carboniferous reef carbonate buildups (Northern Caspian basin). The next geochemical parameters controlled of the gas accumulation histories: (1) West Siberia and Barents Sea regions gas genetically connect with dispersed or concentrated non-marine coal type kerogen distributed into productive complex under lower maturity conditions (before or early oil window zone). This is dry gas almost pure methane with {delta}{sup 13} C{sub 1} between -44,40{per_thousand}. In this case we observe widely distributed mainly sandstones reservoirs at same time gas source rocks also; (2) the Northern Caspian basin found supergiant wet gas-condensate accumulations into local distributed reef carbonate buildups. Gas source rocks is marine kerogen type II, which has a low concentration in marlaceous facies. It is gas high maturity zone.

Lopatin, N. [VNIIgeosystem, Moscow (Russian Federation)

1996-12-31

204

Issues of engineering and geochemistry in the sequestration of carbon dioxide in geological formations-saline aquifers  

NASA Astrophysics Data System (ADS)

Dynamic tests were conducted to evaluate the feasibility to sequester carbon dioxide (CO2) in carbonate dolomite reservoir. Two injection rates, 0.1613 cc/min (20 pore volumes) and 0.982 cc/min (120 pore volumes) were tested to observe changes in petrophysical parameters mainly permeability and porosity under these two conditions of flow rates. The low flow rate was allowed to evaluate the effect of the bulk of the reservoir and the high flow rate evaluated the effect of dissolution on the face of the formation. The testes were carried out at reservoir-simulated conditions (2000 psia and 150°F). San Andres dolomite formation cores from wells 744 and 745 drilled during pilot area evaluation in Levelland Field. The core samples used have a high content of anhydrite and they are cemented mainly by calcite. The formation water used is representative of the Permian basin brine which has sodium 18,000 mg/L, chlorine 46,200 mg/L, calcium 6000 mg/L, sulfate 4880 mg/L, magnesium 1820 mg/L and potassium 1510 mg/L. The injection of low pore volumes was found to reduce the permeability in about 50%, the pore volume and porosity in about 25%, and the total equilibrium magnetization (Mo) from NMR T2 distribution decreased in about 17% indicating substantial reduction in porosity and permeability. The small pore sizes (bulk volume irreducible-BVI) increased in average in about 70% and the large pore sized (free fluid index-FFI) decreased in about 24%. The injection of high pore volume showed slight increase of the petrophysical properties. The total equilibrium magnetization and BVI and FFI did not present remarkable change. At the onset of this research, it was still uncertain how the interaction between CO2 and formation brine affects the geochemistry of the reservoir. Therefore, several static tests at supercritical conditions (1070 psia and 88°F) and at reservoir conditions with and without rock samples were carried out. After running the static tests for seven days, a precipitate from the brine was obtained after reaction with CO2. The precipitate was analyzed using transmission electron microscopy (TEM) to identify the specimen structure and to obtain a chemical analysis using energy-dispersive spectrometers (EDS). Also, the X-ray diffraction method (XRD) was used to identify the new minerals formed as a consequence of the interaction between CO2 and formation brine. The main observations indicate that the precipitated is mainly formed by calcite, gypsum, halite and other mineral salts. (Abstract shortened by UMI.)

Garcia Orrego, Gloria Stella

205

The relationship of dynamical heterogeneity to the Adam-Gibbs and random first-order transition theories of glass formation  

PubMed Central

We carefully examine common measures of dynamical heterogeneity for a model polymer melt and test how these scales compare with those hypothesized by the Adam and Gibbs (AG) and random first-order transition (RFOT) theories of relaxation in glass-forming liquids. To this end, we first analyze clusters of highly mobile particles, the string-like collective motion of these mobile particles, and clusters of relative low mobility. We show that the time scale of the high-mobility clusters and strings is associated with a diffusive time scale, while the low-mobility particles' time scale relates to a structural relaxation time. The difference of the characteristic times for the high- and low-mobility particles naturally explains the well-known decoupling of diffusion and structural relaxation time scales. Despite the inherent difference of dynamics between high- and low-mobility particles, we find a high degree of similarity in the geometrical structure of these particle clusters. In particular, we show that the fractal dimensions of these clusters are consistent with those of swollen branched polymers or branched polymers with screened excluded-volume interactions, corresponding to lattice animals and percolation clusters, respectively. In contrast, the fractal dimension of the strings crosses over from that of self-avoiding walks for small strings, to simple random walks for longer, more strongly interacting, strings, corresponding to flexible polymers with screened excluded-volume interactions. We examine the appropriateness of identifying the size scales of either mobile particle clusters or strings with the size of cooperatively rearranging regions (CRR) in the AG and RFOT theories. We find that the string size appears to be the most consistent measure of CRR for both the AG and RFOT models. Identifying strings or clusters with the “mosaic” length of the RFOT model relaxes the conventional assumption that the “entropic droplets” are compact. We also confirm the validity of the entropy formulation of the AG theory, constraining the exponent values of the RFOT theory. This constraint, together with the analysis of size scales, enables us to estimate the characteristic exponents of RFOT. PMID:23556792

Starr, Francis W.; Douglas, Jack F.; Sastry, Srikanth

2013-01-01

206

The relationship of dynamical heterogeneity to the Adam-Gibbs and random first-order transition theories of glass formation  

NASA Astrophysics Data System (ADS)

We carefully examine common measures of dynamical heterogeneity for a model polymer melt and test how these scales compare with those hypothesized by the Adam and Gibbs (AG) and random first-order transition (RFOT) theories of relaxation in glass-forming liquids. To this end, we first analyze clusters of highly mobile particles, the string-like collective motion of these mobile particles, and clusters of relative low mobility. We show that the time scale of the high-mobility clusters and strings is associated with a diffusive time scale, while the low-mobility particles' time scale relates to a structural relaxation time. The difference of the characteristic times for the high- and low-mobility particles naturally explains the well-known decoupling of diffusion and structural relaxation time scales. Despite the inherent difference of dynamics between high- and low-mobility particles, we find a high degree of similarity in the geometrical structure of these particle clusters. In particular, we show that the fractal dimensions of these clusters are consistent with those of swollen branched polymers or branched polymers with screened excluded-volume interactions, corresponding to lattice animals and percolation clusters, respectively. In contrast, the fractal dimension of the strings crosses over from that of self-avoiding walks for small strings, to simple random walks for longer, more strongly interacting, strings, corresponding to flexible polymers with screened excluded-volume interactions. We examine the appropriateness of identifying the size scales of either mobile particle clusters or strings with the size of cooperatively rearranging regions (CRR) in the AG and RFOT theories. We find that the string size appears to be the most consistent measure of CRR for both the AG and RFOT models. Identifying strings or clusters with the "mosaic" length of the RFOT model relaxes the conventional assumption that the "entropic droplets" are compact. We also confirm the validity of the entropy formulation of the AG theory, constraining the exponent values of the RFOT theory. This constraint, together with the analysis of size scales, enables us to estimate the characteristic exponents of RFOT.

Starr, Francis W.; Douglas, Jack F.; Sastry, Srikanth

2013-03-01

207

The relationship of dynamical heterogeneity to the Adam-Gibbs and random first-order transition theories of glass formation.  

PubMed

We carefully examine common measures of dynamical heterogeneity for a model polymer melt and test how these scales compare with those hypothesized by the Adam and Gibbs (AG) and random first-order transition (RFOT) theories of relaxation in glass-forming liquids. To this end, we first analyze clusters of highly mobile particles, the string-like collective motion of these mobile particles, and clusters of relative low mobility. We show that the time scale of the high-mobility clusters and strings is associated with a diffusive time scale, while the low-mobility particles' time scale relates to a structural relaxation time. The difference of the characteristic times for the high- and low-mobility particles naturally explains the well-known decoupling of diffusion and structural relaxation time scales. Despite the inherent difference of dynamics between high- and low-mobility particles, we find a high degree of similarity in the geometrical structure of these particle clusters. In particular, we show that the fractal dimensions of these clusters are consistent with those of swollen branched polymers or branched polymers with screened excluded-volume interactions, corresponding to lattice animals and percolation clusters, respectively. In contrast, the fractal dimension of the strings crosses over from that of self-avoiding walks for small strings, to simple random walks for longer, more strongly interacting, strings, corresponding to flexible polymers with screened excluded-volume interactions. We examine the appropriateness of identifying the size scales of either mobile particle clusters or strings with the size of cooperatively rearranging regions (CRR) in the AG and RFOT theories. We find that the string size appears to be the most consistent measure of CRR for both the AG and RFOT models. Identifying strings or clusters with the "mosaic" length of the RFOT model relaxes the conventional assumption that the "entropic droplets" are compact. We also confirm the validity of the entropy formulation of the AG theory, constraining the exponent values of the RFOT theory. This constraint, together with the analysis of size scales, enables us to estimate the characteristic exponents of RFOT. PMID:23556792

Starr, Francis W; Douglas, Jack F; Sastry, Srikanth

2013-03-28

208

Geological setting of oil shales in the Permian phosphoria formation and some of the geochemistry of these rocks  

USGS Publications Warehouse

Recent studies of the Meade Peak and the Retort Phosphatic Shale Members of the Phosphoria Formation have investigated the organic carbon content and some aspects of hydrocarbon generation from these rocks. Phosphorite has been mined from the Retort and Meade Peak members in southeastern Idaho, northern Utah, western Wyoming and southwestern Montana. Organic carbon-rich mudstone beds associated with the phosphorite in these two members also were natural sources of petroleum. These mudstone beds were differentially buried throughout the region so that heating of these rocks has been different from place to place. Most of the Phosphoria source beds have been deeply buried and naturally heated to catagenetically form hydrocarbons. Deepest burial was in eastern Idaho and throughout most of the northeastern Great Basin where high ambient temperatures have driven the catagenesis to its limit and beyond to degrade or to destroy the hydrocarbons. In southwest Montana, however, burial in some areas has been less than 2 km, ambient temperatures remained low and the kerogen has not produced hydrocarbons (2). In these areas in Montana, the kerogen in the carbonaceous mudstone has retained the potential for hydrocarbon generation and the carbon-rich Retort Member is an oil shale from which hydrocarbons can be synthetically extracted. The Phosphoria Formation was deposited in a foreland basin between the Cordilleran geosyncline and the North American craton. This foreland basin, which coincides with the area of deposition of the two organic carbon-rich mudstone members of the Phosphoria, has been named the Sublett basin (Maughan, 1979). The basin has a northwest-southeast trending axis and seems to have been deepest in central Idaho where deep-water sedimentary rocks equivalent to the Phosphoria Formation are exceptionally thick. The depth of the basin was increasingly shallower away from central Idaho toward the Milk River uplift - a land area in Montana, the ancestral Rocky Mountains. The basin is composed of land areas in Colorado, the Humboldt highland in northeastern Nevada and intervening carbonate shelves in Utah and Wyoming. The phosphorites and the carbonaceous mudstones were deposited on the foreslope between the carbonate and littoral sand deposits on the shelf and the dominantly cherty mudstone sediments in the axial part of the basin. Paleomagnetic evidence indicates that in the Permian the region would have been within the northern hemispheric trade wind belt; and wind-direction studies determined from studies of sand dunes, indicate that the prevailing winds from the Milk River uplift would have blown offshore across the Phosphoria sea. Offshore winds would have carried surface water away from the shore and generated upwelling in the sea in eastern Idaho and adjacent areas in Montana, Wyoming and Utah. Prior to deposition of the Phosphoria, the region was the site of extensive deposition of shallow-water carbonate sediments. Equivalent rocks in the northern part of the basin are dominantly sandstone derived from the adjacent Milk River uplift and similar sandstone strata in the southeastern sector were derived from the ancestral Rocky Mountains uplift. Tectonic subsidence of the Sublett basin in part of the region seems to have provided a sea-floor profile favorable for upwelling circulation and the shift in deposition from regional carbonates and local sandstone into a more complex depositional pattern that included the accumulation of the mudstone-chert-phosphorite facies that comprises the Phosphoria Formation. High biological productivity and the accumulation of sapropel on the sea floor is associated with contemporary coastal upwelling (1) and similar environmental and depositional conditions are attributed to the rich accumulations of organic matter in the Phosphoria Formation. Sapropelic mudstone and phosphorite composing the Meade Peak Member are approximately 60 m thick near the center of the Sublett basin. The Meade

Maughan, E.K.

1983-01-01

209

Separation and capture of CO2 from large stationary sources and sequestration in geological formations--coalbeds and deep saline aquifers.  

PubMed

The topic of global warming as a result of increased atmospheric CO2 concentration is arguably the most important environmental issue that the world faces today. It is a global problem that will need to be solved on a global level. The link between anthropogenic emissions of CO2 with increased atmospheric CO2 levels and, in turn, with increased global temperatures has been well established and accepted by the world. International organizations such as the United Nations Framework Convention on Climate Change (UNFCCC) and the Intergovernmental Panel on Climate Change (IPCC) have been formed to address this issue. Three options are being explored to stabilize atmospheric levels of greenhouse gases (GHGs) and global temperatures without severely and negatively impacting standard of living: (1) increasing energy efficiency, (2) switching to less carbon-intensive sources of energy, and (3) carbon sequestration. To be successful, all three options must be used in concert. The third option is the subject of this review. Specifically, this review will cover the capture and geologic sequestration of CO2 generated from large point sources, namely fossil-fuel-fired power gasification plants. Sequestration of CO2 in geological formations is necessary to meet the President's Global Climate Change Initiative target of an 18% reduction in GHG intensity by 2012. Further, the best strategy to stabilize the atmospheric concentration of CO2 results from a multifaceted approach where sequestration of CO2 into geological formations is combined with increased efficiency in electric power generation and utilization, increased conservation, increased use of lower carbon-intensity fuels, and increased use of nuclear energy and renewables. This review covers the separation and capture of CO2 from both flue gas and fuel gas using wet scrubbing technologies, dry regenerable sorbents, membranes, cryogenics, pressure and temperature swing adsorption, and other advanced concepts. Existing commercial CO2 capture facilities at electric power-generating stations based on the use of monoethanolamine are described, as is the Rectisol process used by Dakota Gasification to separate and capture CO2 from a coal gasifier. Two technologies for storage of the captured CO2 are reviewed--sequestration in deep unmineable coalbeds with concomitant recovery of CH4 and sequestration in deep saline aquifers. Key issues for both of these techniques include estimating the potential storage capacity, the storage integrity, and the physical and chemical processes that are initiated by injecting CO2 underground. Recent studies using computer modeling as well as laboratory and field experimentation are presented here. In addition, several projects have been initiated in which CO2 is injected into a deep coal seam or saline aquifer. The current status of several such projects is discussed. Included is a commercial-scale project in which a million tons of CO2 are injected annually into an aquifer under the North Sea in Norway. The review makes the case that this can all be accomplished safely with off-the-shelf technologies. However, substantial research and development must be performed to reduce the cost, decrease the risks, and increase the safety of sequestration technologies. This review also includes discussion of possible problems related to deep injection of CO2. There are safety concerns that need to be addressed because of the possibilities of leakage to the surface and induced seismic activity. These issues are presented along with a case study of a similar incident in the past. It is clear that monitoring and verification of storage will be a crucial part of all geological sequestration practices so that such problems may be avoided. Available techniques include direct measurement of CO2 and CH4 surface soil fluxes, the use of chemical tracers, and underground 4-D seismic monitoring. Ten new hypotheses were formulated to describe what happens when CO2 is pumped into a coal seam. These hypotheses provide significant insight into the fundamental chemical, physical, a

White, Curt M; Strazisar, Brian R; Granite, Evan J; Hoffman, James S; Pennline, Henry W

2003-06-01

210

Measuring resistivity changes from within a first cased well to monitor fluids injected into oil bearing geological formations from a second cased well while passing electrical current between the two cased wells  

DOEpatents

A.C. current is conducted through geological formations separating two cased wells in an oil field undergoing enhanced oil recovery operations such as water flooding operations. Methods and apparatus are disclosed to measure the current leakage conducted into a geological formation from within a first cased well that is responsive to fluids injected into formation from a second cased well during the enhanced oil production activities. The current leakage and apparent resistivity measured within the first cased well are responsive to fluids injected into formation from the second cased well provided the distance of separation between the two cased wells is less than, or on the order of, a Characteristic Length appropriate for the problem.

Vail, III, William B. (Bothell, WA)

1993-01-01

211

Measuring resistivity changes from within a first cased well to monitor fluids injected into oil bearing geological formations from a second cased well while passing electrical current between the two cased wells  

DOEpatents

A.C. current is conducted through geological formations separating two cased wells in an oil field undergoing enhanced oil recovery operations such as water flooding operations. Methods and apparatus are disclosed to measure the current leakage conducted into a geological formation from within a first cased well that is responsive to fluids injected into formation from a second cased well during the enhanced oil production activities. The current leakage and apparent resistivity measured within the first cased well are responsive to fluids injected into formation from the second cased well provided the distance of separation between the two cased wells is less than, or on the order of, a Characteristic Length appropriate for the problem.

Vail, W.B. III.

1993-02-16

212

[Spatiotemporal heterogeneity and its formation causes of soil physical properties in karst peak-cluster depression area of northwest Guangxi, China].  

PubMed

Soil samples were collected from the grassland, shrub land, secondary forest, and original forest on the hill slope in a typical karst peak-cluster depression area of northwest Guanxi, with the spatiotemporal heterogeneity of soil physical properties investigated by classical statistics, and the formation causes of the heterogeneity analyzed by redundancy analysis (RDA). In 0-15 cm soil layer, the clay (< 0.002 mm) and silt (0.002-0.05 mm) contents of shrub land and original forest had significant differences with those of grassland and secondary forest, respectively, but the clay, silt, and sand (0.05-2.0 mm) contents had no significant differences between grassland and secondary forest. No significant difference was observed in the soil sand content among the four land types, but the soil bulk density of grassland was significantly different from that of other three land types. The soil clay content of grassland increased with increasing elevation, while that of the other three land types was the highest on medium slope, and had no significant differences for the same land types among different slope locations. The soil clay content in different layers of 0-30 cm had a greater variation extent in original forest (14.55%) than in grassland (7.12%), shrub land (11.24%), and secondary forest (13.77%), and the soil particle size composition was greatly affected by the disturbance of human activities. Soil organic carbon (SOC) and vegetation type were the dominant factors affecting the soil physical properties, and the bare rock ratio had greater effects on soil sand content. PMID:21265145

Liu, Shu-juan; Zhang, Wei; Wang, Ke-lin; Chen, Hong-song; Wei, Guo-fu

2010-09-01

213

Formation of gas-phase carbonyls from heterogeneous oxidation of polyunsaturated fatty acids at the air-water interface and of the sea surface microlayer  

NASA Astrophysics Data System (ADS)

Motivated by the potential for reactive heterogeneous chemistry occurring at the ocean surface, gas-phase products were observed when a reactive sea surface microlayer (SML) component, i.e. the polyunsaturated fatty acid (PUFA) linoleic acid (LA), was exposed to gas-phase ozone at the air-seawater interface. Similar oxidation experiments were conducted with SML samples collected from two different oceanic locations, in the eastern equatorial Pacific Ocean and from the west coast of Canada. Online proton-transfer-reaction mass spectrometry (PTR-MS) and light-emitting diode cavity enhanced differential optical absorption spectroscopy (LED-CE-DOAS) were used to detect oxygenated gas-phase products from the ozonolysis reactions. The LA studies indicate that oxidation of a PUFA monolayer on seawater gives rise to prompt and efficient formation of gas phase aldehydes. The products are formed via the decomposition of primary ozonides which form upon the initial reaction of ozone with the carbon-carbon double bonds in the PUFA molecules. In addition, two highly reactive di-carbonyls, malondialdehyde (MDA) and glyoxal, were also generated, likely as secondary products. Specific yields relative to reactant loss were 78%, 29%, 4% and <1% for n-hexanal, 3-nonenal, MDA and glyoxal, respectively, where the yields for MDA and glyoxal are likely lower limits. Heterogeneous oxidation of SML samples confirm for the first time that similar carbonyl products are formed via ozonolysis of environmental samples. The potential impact of such chemistry on the atmosphere of the marine boundary layer is discussed.

Zhou, S.; Gonzalez, L.; Leithead, A.; Finewax, Z.; Thalman, R.; Vlasenko, A.; Vagle, S.; Miller, L.; Li, S.-M.; Bureekul, S.; Furutani, H.; Uematsu, M.; Volkamer, R.; Abbatt, J.

2013-07-01

214

The Geology of the Terrestrial Planets  

NASA Technical Reports Server (NTRS)

The geologic history of the terrestrial planets is outlined in light of recent exploration and the revolution in geologic thinking. Among the topics considered are planet formation; planetary craters, basins, and general surface characteristics; tectonics; planetary atmospheres; and volcanism.

Carr, M. H. (editor); Saunders, R. S.; Strom, R. G.; Wilhelms, D. E.

1984-01-01

215

Sudbury project (University of Muenster-Ontario Geological Survey): Origin of the polymict, allochthonous breccias of the Onaping Formation  

NASA Technical Reports Server (NTRS)

The Sudbury structure has been interpreted as a deeply eroded remnant of a peak-ring basin. The polymict, allochthonous breccias of the Onaping Formation (OF) occur in the central part of the Sudbury structure, which is surrounded by the 1.85-Ga-old 'Sudbury Igneous Complex' (SIC). From bottom to top the OF can be divided into Basal, Gray, Green, and lower and upper Black members. The breccias were mapped in detail in the east range of the structure. The SIC and the lower part of the OF (Basal Member) are interpreted as the impact melt system. The overlying Gray Member is a breccia unit with a clastic matrix and has a sharp contact to the Basal Member. The Green Member is considered as a continuous uniform breccia layer on top of the Gray Member and comprises the former 'chlorite shard horizon'. The uppermost unit of the OF (Black Member) can be subdivided into a lower and an upper Black Member unit. The lower part (100-150 m thick) still shows petrographic features of suevitic breccias, small fragments of basement rocks, melt particles, chloritized particles, and breccia fragments in a dark, clastic matrix.

Avermann, M. E.

1992-01-01

216

Utah Geology  

NSDL National Science Digital Library

Utah Geological Survey's Web site, Utah Geology, offers a variety of interesting geological information about the state. Good descriptions, illustrations, and photographs can be accessed on earthquakes and hazards, dinosaurs and fossils, rocks and minerals, oil and energy, and more. For example, the Rocks and Minerals page contains everything from how to stake a mining claim to downloadable summaries of mineral activity in the state. There is quite a bit of information within the site, and anyone interested in geology will find themselves exploring these pages for quite a while.

2001-01-01

217

Geology Fieldnotes: Timpanogos National Monument, Utah  

NSDL National Science Digital Library

Timpanogos Cave National Monument, in the Wasatch Mountains, features spectacularly decorated caverns, each of which has unique colors and formations. Features of the site include park geology information, maps, photographs of cave formations, related links, and visitor information. The park geology section discusses the caves' geologic history, structural geology, and details the discovery of the Hansen and Middle Caves (by Martin, George, and Wayne Hansen) and the Timpanogos Cave (by Veral Manwill).

218

Heterogeneous atmospheric chemistry  

NASA Technical Reports Server (NTRS)

The present conference on heterogeneous atmospheric chemistry considers such topics concerning clusters, particles and microparticles as common problems in nucleation and growth, chemical kinetics, and catalysis, chemical reactions with aerosols, electron beam studies of natural and anthropogenic microparticles, and structural studies employing molecular beam techniques, as well as such gas-solid interaction topics as photoassisted reactions, catalyzed photolysis, and heterogeneous catalysis. Also discussed are sulfur dioxide absorption, oxidation, and oxidation inhibition in falling drops, sulfur dioxide/water equilibria, the evidence for heterogeneous catalysis in the atmosphere, the importance of heterogeneous processes to tropospheric chemistry, soot-catalyzed atmospheric reactions, and the concentrations and mechanisms of formation of sulfate in the atmospheric boundary layer.

Schryer, D. R.

1982-01-01

219

California Geological Survey: Geologic Maps  

NSDL National Science Digital Library

This index provides access to a selection of geologic maps of California, as well as an overview of geologic and other mapping activities in the state. The index, which can be accessed by clicking on an interactive map of the state, contains lists of selected geologic maps in California prepared by the Regional Geologic Mapping Project (RGMP). The RGMP staff monitors the literature and collects references that contain geologic mapping that may be useful for future compilations. In addition, the site has information about Caltrans Highway Corridor Mapping, The Mineral Resources and Mineral Hazards Mapping Program, North Coast Watersheds Assessment Program, The Timber Harvesting Plan Enforcement Program, and The Seismic Hazards Mapping Program. A set of links is provided to other sources of geologic maps and map information.

220

Yellowstone Geology  

NSDL National Science Digital Library

This Yellowstone National Park website provides geological information about the Park. Links include geologic highlights, hydrothermal features, reports by park geologists, and scientists' talks (videos). A wide array of information can be found on these links and the webpage is expanding as more topics are added.

Park, Yellowstone N.

221

Physical geology  

SciTech Connect

The book integrates current thinking on processes (plate techtonics, chemical cycles, changes throughout geologic time). It is an introduction to investigations into the way the earth works, how mountains are formed, how the atmosphere, hydrosphere, crust and mantle interact with each other. Treatments on climate, paleoclimatology and landscape evolution are included, as is a discussion on how human activity affects geological interactions.

Skinner, B.; Porter, S.

1987-01-01

222

Geology of Jewel Cave  

NSDL National Science Digital Library

This National Park Service site provides an introduction to the Black Hill's Jewel Cave. The site describes the unique geologic history of the Black Hills, the formation of speleothems as well as unusual crystal growth in the cave. Photographs illustrate the descriptions.

National Park Services (NPS)

223

Briefing on geological sequestration  

EPA Science Inventory

Geological sequestration (GS) is generally recognized as the injection and long-term (e.g., hundreds to thousands of years) trapping of gaseous, liquid or supercritical carbon dioxide (CO2) in subsurface media ? primarily saline formations, depleted or nearly depleted oil and gas...

224

'Heterogeneous Beliefs and Instability'  

Microsoft Academic Search

While Rational Expectations have dominated the paradigm of expectations formation, they have been more recently challenged on the empirical ground such as, for instance, in the dynamics of the exchange rate. This challenge has led to the introduction of heterogeneous expectations in economic modeling. More specifically, the forecasts of the market participants have been drawn from competing views. Two behaviours

Laurence Lasselle; Serge Svizzero; Clem Tisdell

2001-01-01

225

No geology without marine geology  

Microsoft Academic Search

A brief review is offered of the many problems where knowledge of the ocean floors and of marine processes in shallow water is indispensable for the further advancement of geology. The subject of turbidity currents is treated in greater detail, to demonstrate the interrelation of several aspects of marine geology with sedimentologic and paleogeographic investigations. It is obvious that the

P. H Kuenen

2002-01-01

226

Geologic History  

NSDL National Science Digital Library

This unit introduces younger students to the concept of relative versus absolute time and how geologists determine the age of geologic events and features. Topics include the laws that determine relative age (superposition, cross-cutting relationships, included fragments, and others), and how to re-construct the geologic history of an area using these relationships. There is also information on geologic correlation and the use of index fossils to determine relative age. The section on absolute time discusses some ways of measurement (tree rings, radioactive dating) and introduces the concepts of natural selection and mass extinctions. A vocabulary and downloadable, printable student worksheets are provided.

Medina, Philip

2010-09-03

227

Geologic Time  

NSDL National Science Digital Library

The Earth is very old -- 4.5 billion years or more -- according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

Newman, William L.

1997-01-01

228

Geologic Timeline  

NSDL National Science Digital Library

Dive into the depths of time with this Geologic Timeline. The farther you scroll down, the farther back in time you'll travel. Also, the longer a period is on this page, the longer it lasted in history!

2000-01-01

229

Monitoring of Water and Thermic Transfers in the Vadose Zone of a Geological Carbonate Formation : Example of and Underground Quarry, Gironde, France  

NASA Astrophysics Data System (ADS)

The aim of this study is the monitoring of water and thermic transfers in vadose zone of a geological carbonate formation during three hydrological cycles (August 2001- November 2004). The application of the Time Domain Reflectometry (TDR) and Self-Potential (SP) methods to determine the water content of porous rock has been widely investigated. More than 285 studied point measurements of rock water content observed during three hydrological cycles and distributed among an abandoned underground quarry in Gironde, France, show a permanently undersaturated limestone (between 35 and 50 percents). We also investigated the unsaturated zone in a borehole between 0 and 20 m depth until the water table. 14 TDR and SP electrodes investigate the vadose zone. For the understanding of the streaming potential and electric behaviour from the SP method of a vadose zone we performed an experimental device which allows us to quantify the measurements of electrokinetic coupling coefficient at various saturation conditions. The results show that the vadose zone is characterized by three different sub-zones which are different water dynamics. The shallow zone down to a depth of seven meters corresponds to a zone with a significant variation of water saturation related to evapotranspiration dynamic water. The second zone (so-called transition zone) between seven to sixteen meters displays a high stability. The third zone (zone of capillary fringe) between sixteen to twenty meter shows a high and constant water saturation. Experimental results show three periods of maximum water content corresponding to three occurring effective precipitations. The dephasing and the amplitude attenuation of the hydraulic and thermic waves with the depth can be modelled and explained by the physical properties of the porous medium in an unsaturated zone such as the diffusivity, the water relative permeability, the capillarity pressure versus water saturation and the effective porosity.

Cerepi, A.; Loisy, C.; Burlot, R.; Mao, L.

2007-12-01

230

Impacts of Anthropogenic Emissions in the Southeastern U.S. on Heterogeneous Chemistry of Isoprene-Derived Epoxides Leading to Secondary Organic Aerosol Formation (Invited)  

NASA Astrophysics Data System (ADS)

Isoprene is a major source of secondary organic aerosol (SOA); however, the exact manner in which it forms SOA remains unclear. Improving our fundamental understanding of isoprene-derived SOA is key to improving existing air quality models, especially in the southeastern U.S. where models currently underestimate observations. By combining organic synthesis, computational calculations, mass spectrometry, smog chamber studies, and field measurements, we show that reactive epoxides, which include methacrylic acid epoxide (MAE) and isomeric isoprene epoxydiols (IEPOX), produced from the photochemical oxidation of isoprene are key to SOA formation. Furthermore, anthropogenic pollutants (NOx and SO2) enhance isoprene-derived epoxides as an SOA source. In the laboratory, we find that the reactive uptake of synthetic IEPOX and MAE standards onto acidified sulfate aerosol yields known isoprene-derived SOA tracers (2-methlytetrols, 2-methylglyceric acid, C5-alkene triols, 3-methyltetrahydrofuran-3,4-diols, dimers and organosulfates) that we measure in fine aerosol collected from multiple sites across the southeastern U.S. using gas chromatography/mass spectrometry (GC/MS) and liquid chromatography coupled to diode array detection and electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (LC/DAD-ESI-QTOFMS). Notably, IEPOX- and MAE-derived SOA tracers account for ~19% of the organic aerosol mass in Yorkville, GA. Moreover, real-time continuous chemical measurements of fine aerosol made using an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) during summer 2011 and summer 2013 in Atlanta, GA, and Look Rock, TN, respectively, resolved an IEPOX-oxygenated organic aerosol (IEPOX-OOA) factor when applying positive matrix factorization (PMF) to the organic mass spectral time series. In Atlanta, this factor is found to account for ~33% of the fine OA mass and is correlated with IEPOX-derived SOA tracers (r2 = 0.6), sulfate (r2 = 0.5), and to some extent with aerosol acidity (measured as nmol H+ m-3, r2 = 0.3). Altogether, the Community Multiscale Air Quality model is updated to predict isoprene aerosol from IEPOX and MAE. The new aqueous aerosol pathways allow for explicit predictions of IEPOX- and MAE-derived SOA tracers that are more consistent with observations than estimates based on semivolatile partitioning, supporting the role of acid-catalyzed heterogeneous reactions leading to SOA formation.

Surratt, J. D.; Pye, H.; Lin, Y.; Budisulistiorini, S.; Zhang, H.; Marth, W.; Cui, T.; Arashiro, M.; Chu, K.; Zhang, Z.; Sexton, K.; Piletic, I.; Xie, Y.; Capps, S. L.; Luecken, D.; Hutzell, W. T.; Jaoui, M.; Canagaratna, M. R.; Croteau, D.; Jayne, J. T.; Worsnop, D. R.; Offenberg, J.; Kleindienst, T. E.; Lewandowski, M.; Edney, E.; Pinder, R. W.; Bartolotti, L.; Gold, A.

2013-12-01

231

Geological and Tectonic Evidence for the Formation and Extensional Collapse of the West Antarctic Plateau: Implications for the Formation of the West Antarctic Rift System and the Transantarctic Mountains  

NASA Astrophysics Data System (ADS)

The Transantarctic Mountains (TAM), the world's longest and highest non-contractional intracontinental mountain belt, define the western boundary of the West Antarctic rift system (WARS). The WARS is a broad region of extended continental lithosphere, ca. 750-1000 km wide, lying dominantly below sea-level. A new model (Bialas et al., 2007), proposes that a region of thickened continental crust and high-standing topography, the "West Antarctic Plateau", underwent extensional collapse to leave a remnant edge representing the proto-TAM. Tectonic and paleogeographic reconstructions indicate the plateau formed inboard of a continental arc along the paleo- Pacific margin of Antarctica, active throughout the Paleozoic until the late Mesozoic. This high-standing region was responsible for confining sediments (Beacon Supergroup) to elongate basins along the length of the TAM. Much of the present region of the WARS has been correlated with the Lachlan Fold belt of southeastern Australia. This belt formed from the Ordovician to Carboniferous during back-arc basin formation associated with slab roll- back with short periods of compression. Convergence along the paleo-Pacific margin, perhaps enhanced by subduction of more buoyant oceanic lithosphere as the Phoenix-Pacific ridge was obliquely subducted, resulted in crustal thickening and formation of high-standing terrain (the plateau). Extensional collapse of the plateau most likely began in the Jurassic during initial rifting between East and West Antarctica, but was mainly accomplished during distributed rifting in the Cretaceous (ca. 105-85) following subduction of the Phoenix-Pacific ridge and prior to the separation of New Zealand from Marie Byrd Land. Continued formation of the TAM continued in the Cenozoic concomitant with extension in the WARS that was localized along its western margin adjacent to the TAM. Glacial erosion in the Oligocene and early-Miocene enhanced peak height in the TAM. In this presentation we discuss the diverse geological, geophysical, thermochronological and tectonic evidence for the West Antarctic Plateau and the implications for the formation of the Transantarctic Mountains.

Fitzgerald, P. G.; Studinger, M.; Bialas, R. W.; Buck, W.

2007-12-01

232

Structural and stratigraphic evolution of the central Mississippi Canyon Area: interaction of salt tectonics and slope processes in the formation of engineering and geologic hazards  

E-print Network

Approximately 720 square miles of digital 3-dimensional seismic data covering the eastern Mississippi Canyon area, Gulf of Mexico, continental shelf was used to examine the structural and stratigraphic evolution of the geology in the study area...

Brand, John Richard

2006-04-12

233

Input-form data for the U.S. Geological Survey assessment of the Devonian and Mississippian Bakken and Devonian Three Forks Formations of the U.S. Williston Basin Province, 2013  

USGS Publications Warehouse

In 2013, the U.S. Geological Survey assessed the technically recoverable oil and gas resources of the Bakken and Three Forks Formations of the U.S. portion of the Williston Basin. The Bakken and Three Forks Formations were assessed as continuous and hypothetical conventional oil accumulations using a methodology similar to that used in the assessment of other continuous- and conventional-type assessment units throughout the United States. The purpose of this report is to provide supplemental documentation and information used in the Bakken-Three Forks assessment.

Gaswirth, Stephanie B.; Marra, Kristen R.; Cook, Troy A.; Charpentier, Ronald R.; Gautier, Donald L.; Higley, Debra K.; Klett, Timothy R.; Lewan, Michael D.; Lillis, Paul G.; Schenk, Christopher J.; Tennyson, Marilyn E.; Whidden, Katherine J.

2013-01-01

234

A study of the relationship of geological formation to the norm. Quarterly technical progress report, July 1, 1995--September 30, 1995  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During the fourth quarter of this project, emphasis was placed on three major tasks; identifying new sampling sites, continuance of preliminary geologic data acquisition, and determining acceptable project revisions.

Bursh, T.P.; Chriss, D.

1995-10-18

235

Geologic controls influencing CO2 loss from a leaking well.  

SciTech Connect

Injection of CO2 into formations containing brine is proposed as a long-term sequestration solution. A significant obstacle to sequestration performance is the presence of existing wells providing a transport pathway out of the sequestration formation. To understand how heterogeneity impacts the leakage rate, we employ two dimensional models of the CO2 injection process into a sandstone aquifer with shale inclusions to examine the parameters controlling release through an existing well. This scenario is modeled as a constant-rate injection of super-critical CO2 into the existing formation where buoyancy effects, relative permeabilities, and capillary pressures are employed. Three geologic controls are considered: stratigraphic dip angle, shale inclusion size and shale fraction. In this study, we examine the impact of heterogeneity on the amount and timing of CO2 released through a leaky well. Sensitivity analysis is performed to classify how various geologic controls influence CO2 loss. A 'Design of Experiments' approach is used to identify the most important parameters and combinations of parameters to control CO2 migration while making efficient use of a limited number of computations. Results are used to construct a low-dimensional description of the transport scenario. The goal of this exploration is to develop a small set of parametric descriptors that can be generalized to similar scenarios. Results of this work will allow for estimation of the amount of CO2 that will be lost for a given scenario prior to commencing injection. Additionally, two-dimensional and three-dimensional simulations are compared to quantify the influence that surrounding geologic media has on the CO2 leakage rate.

Hopkins, Polly L.; Martinez, Mario J.; McKenna, Sean Andrew; Klise, Katherine A.

2010-12-01

236

Antarctica Geology  

NSDL National Science Digital Library

This site contains information about the continent of Antarctica. There is a classroom practice and instructional module. The students will be able to describe the general geology of the land under the Antarctic ice and to explain from where the rocks may have come.

237

Geologic Time  

NSDL National Science Digital Library

This site contains 24 questions on the topic of geologic time, which covers dating techniques and unconformities. This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate feedback.

Heaton, Timothy

238

Reaction capacity characterization of shallow sedimentary deposits in geologically different regions of the Netherlands.  

PubMed

Quantitative insight into the reaction capacity of porous media is necessary to assess the buffering capacity of the subsurface against contaminant input via groundwater recharge. Here, reaction capacity is to be considered as a series of geochemical characteristics that control acid/base conditions, redox conditions and sorption intensity. Using existing geochemical analyses, a statistical regional assessment of the reaction capacity was performed for two geologically different areas in the Netherlands. The first area is dominated by Pleistocene aquifer sediments only, in the second area a heterogeneous Holocene confining layer is found on top of the Pleistocene aquifer sediments. Within both areas, two or more regions can be distinguished that have a distinctly different geological build-up of the shallow subsurface. The reactive compounds considered were pyrite, reactive Fe other than pyrite, sedimentary organic matter, carbonate and clay content. This characterization was complemented by the analysis of a dataset of samples newly collected, from two regions within the Pleistocene area, where the sedimentary facies of samples was additionally distinguished. The statistical assessment per area was executed at the levels of region, geological formation and lithology class. For both areas, significant differences in reaction capacities were observed between: 1. different lithology classes within a geological formation in a single region, 2. identical geological formations in different regions and 3. various geological formations within a single region. Here, the reaction capacity is not only controlled by lithostratigraphy, but also by post-depositional diagenesis and paleohydrology. Correlation coefficients among the reactive compounds were generally higher for sand than for clay, but insufficiently high to allow good estimation of reactive compounds from each other. For the sandy Pleistocene aquifer sediments, the content of reactive compounds was frequently observed to be below detection limits. From this, future characterization of sediment reaction capacity is best performed at the sublevel of lithology class, being the geochemically near-uniform unit identifiable for individual geological formations within geographic regions. Additional subdivision on facies provides particular insight in the spatial entity where relatively high reaction capacities may be encountered. To obtain quantitative insight into the reaction capacity of aquifer sediments, non-sandy minor subunits should be well characterised on their reaction capacity as well as their spatial occurrence in the geological formations. A straightforward approach is presented in which the regional statistics on geochemical reactivity become combined with a 3-dimensional geological voxel model. This results into 3-dimensional data fields on reactivity, which are suitable for, for example, groundwater transport modelling. The sedimentological architecture of the deposits becomes well maintained in the geochemical data field, which is an advantage in itself. PMID:21549444

Griffioen, Jasper; Klein, Janneke; van Gaans, Pauline F M

2012-01-01

239

Si-rich layer formation on olivine surfaces during reaction with water and supercritical carbon dioxide under conditions relevant for geologic carbon storage  

NASA Astrophysics Data System (ADS)

The reaction of Mg-silicate minerals (i.e. olivine) with carbon dioxide (CO2) is a promising method for secure, long-term, geologic carbon storage. Several technical challenges must be overcome before implementing mineral carbonation technology on a large scale, one of which is slow reaction kinetics. This study probes surface reaction limitations of olivine carbonation, specifically the formation of a passivating, Si-rich layer on olivine surfaces upon exposure to water and CO2 under sequestration conditions (elevated temperature and pressure). A series of batch reactions were performed at 60°C and 100 bar CO2 pressure in Dickson-style rocker bombs, varying the length of reaction and the amount of mixing (rocking). The initial aqueous phase was spiked with 29Si. Fluid samples were taken periodically and analyzed for cation content, alkalinity, and dissolved inorganic carbon. At the end of each experiment, the solid products were analyzed with a Sensitive High Resolution Ion Microprobe Reverse Geometry (SHRIMP-RG) in order to measure the amount of 29Si incorporated into the Si-rich layer on reacted olivine grains. We also cut cross sections of reacted grains from each experiment using a Focused Ion Beam (FIB) which were thinned to <100nm and imaged using Transmission Electron Microscopy (TEM). SHRIMP-RG results show incorporation of 29Si on olivine grain surfaces reacted for 19 days with no mixing, and TEM images of olivine grains from the same experiment show an amorphous, Si-rich layer that is 30nm thick. Similarly, SHRIMP-RG results for olivine grains reacted for 19 days with mixing indicate 29SiO2 precipitation and TEM images reveal a Si-rich layer 60nm thick. In both experiments, EDS (energy dispersive spectroscopy) data show a step change in composition from the bulk rock to the surface layer in addition to the sharp crystalline/amorphous interface visible in the TEM images. Olivine from the unmixed experiment also has a slow decrease in Mg relative to Si before the step change, suggesting that, at least in this experiment, a Si-rich layer precipitated on top of a Mg-depleted layer that formed via a leaching process. SHRIMP-RG data also imply the presence of a precipitated Si-rich layer on top of a leached Si-rich layer, as the 29Si penetration depth is only 25-65% of the total Si-rich layer thickness. The combination of SHRIMP-RG and FIB/TEM analysis leads us to hypothesize that a Si-rich layer forms quickly on olivine surfaces due to preferential Mg removal from the surface (the traditional 'leached' layer), and as the reaction proceeds, amorphous silica reaches saturation in the fluid and precipitates on surfaces inside the reactor (including olivine grains).

Johnson, N. C.; Jackson, A.; Maher, K.; Bird, D. K.; Brown, G. E.

2013-12-01

240

Geologic control of natural marine hydrocarbon seep emissions, Coal Oil Point seep field, California  

E-print Network

Coal Oil Point seep field, underlying geologic structure showing the Monterey Formation (Formation dips north, with the steepest portions along the CoalCoal Oil Point seep field distribution, underlying geologic structure showing faults, Monterey Formation (

Leifer, Ira; Kamerling, Marc J.; Luyendyk, Bruce P.; Wilson, Douglas S.

2010-01-01

241

Fe(HSO 4) 3 as an inexpensive, eco-friendly, heterogeneous and reusable catalyst for acetal\\/ketal formation and their facile regeneration  

Microsoft Academic Search

Fe(HSO4)3 has been used as an efficient and recyclable catalyst for acetalization and ketalization of carbonyl compounds with neopentyl glycol. The advantage of this method is the use of a novel catalyst system which is inexpensive, heterogeneous and stable with an easy procedure and short reaction times. The catalyst can be recovered and reused without significant loss of activity. In

Hossein Eshghi; Mohammad Rahimizadeh; Sattar Saberi

2008-01-01

242

Geologic Time  

NSDL National Science Digital Library

This Classroom Connectors lesson plan discusses the characteristics of geologic time, including the law of superposition, fossil preservation, casts and molds, and various events through the history of the Earth. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

243

Method of analysis at the U.S. Geological Survey California Water Science Center, Sacramento Laboratory - determination of haloacetic acid formation potential, method validation, and quality-control practices  

USGS Publications Warehouse

An analytical method for the determination of haloacetic acid formation potential of water samples has been developed by the U.S. Geological Survey California Water Science Center Sacramento Laboratory. The haloacetic acid formation potential is measured by dosing water samples with chlorine under specified conditions of pH, temperature, incubation time, darkness, and residual-free chlorine. The haloacetic acids formed are bromochloroacetic acid, bromodichloroacetic acid, dibromochloroacetic acid, dibromoacetic acid, dichloroacetic acid, monobromoacetic acid, monochloroacetic acid, tribromoacetic acid, and trichloroacetic acid. They are extracted, methylated, and then analyzed using a gas chromatograph equipped with an electron capture detector. Method validation experiments were performed to determine the method accuracy, precision, and detection limit for each of the compounds. Method detection limits for these nine haloacetic acids ranged from 0.11 to 0.45 microgram per liter. Quality-control practices include the use of blanks, quality-control samples, calibration verification standards, surrogate recovery, internal standard, matrix spikes, and duplicates.

Zazzi, Barbara C.; Crepeau, Kathryn L.; Fram, Miranda S.; Bergamaschi, Brian A.

2005-01-01

244

Upper Cenozoic Geologic Map, Yellowstone Plateau Volcanic Field  

NSDL National Science Digital Library

This geologic map shows Tertiary and Quaternary rock formations, volcanic and surficial deposits, faults, contacts, and other geologic features in Yellowstone National Park. The map is freely downloadable as a PDF file.

Robert, Christiansen; Survey, U. S.

245

Fold origin of the NE-lobe of the Sudbury Basin, Canada: Evidence from heterogeneous fabric development in the Onaping Formation and the Sudbury Igneous Complex  

Microsoft Academic Search

Structural analysis of the Onaping Formation, a heterolithic impact melt breccia, and the Granophyre in the NE-lobe of the 1.85Ga Sudbury Igneous Complex (SIC) assist in understanding the formation of the Sudbury Basin. Previously, the lack of mesoscopic strain fabrics in the SIC, in contrast to pervasive fabrics in the Onaping Formation of the NE-lobe, led to interpretations of the

Christian Klimczak; Andrea Wittek; Daniel Doman; Ulrich Riller

2007-01-01

246

A study of the relationship of geological formation to the NORM. Quarterly technical progress report, January 1, 1997--March 31, 1997  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combatting this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During the tenth quarter of this project, emphasis again remained on two major tasks; identifying new sampling sites and seeking approval for final project revisions. In light of the delays experienced, the project has been granted a one year extension, and a revision is currently under review.

Bursh, T.P.; Chriss, D.

1997-04-20

247

Journal of the Geological Society, London, Vol. 163, 2006, pp. 561576. Printed in Great Britain. The Pennsylvanian tropical biome reconstructed from the Joggins Formation of  

E-print Network

) Joggins Formation contains a diverse fossil assemblage, first made famous by Lyell and Dawson in the mid. 561 The Pennsylvanian tropical biome reconstructed from the Joggins Formation of Nova Scotia, Canada H-19th century. Collector curves based on c. 150 years of observation suggest that the Joggins fossil

Benton, Michael

248

Co2 geological sequestration  

SciTech Connect

Human activities are increasingly altering the Earth's climate. A particular concern is that atmospheric concentrations of carbon dioxide (CO{sub 2}) may be rising fast because of increased industrialization. CO{sub 2} is a so-called ''greenhouse gas'' that traps infrared radiation and may contribute to global warming. Scientists project that greenhouse gases such as CO{sub 2} will make the arctic warmer, which would melt glaciers and raise sea levels. Evidence suggests that climate change may already have begun to affect ecosystems and wildlife around the world. Some animal species are moving from one habitat to another to adapt to warmer temperatures. Future warming is likely to exceed the ability of many species to migrate or adjust. Human production of CO{sub 2} from fossil fuels (such as at coal-fired power plants) is not likely to slow down soon. It is urgent to find somewhere besides the atmosphere to put these increased levels of CO{sub 2}. Sequestration in the ocean and in soils and forests are possibilities, but another option, sequestration in geological formations, may also be an important solution. Such formations could include depleted oil and gas reservoirs, unmineable coal seams, and deep saline aquifers. In many cases, injection of CO2 into a geological formation can enhance the recovery of hydrocarbons, providing value-added byproducts that can offset the cost of CO{sub 2} capture and sequestration. Before CO{sub 2} gas can be sequestered from power plants and other point sources, it must be captured. CO{sub 2} is also routinely separated and captured as a by-product from industrial processes such as synthetic ammonia production, H{sub 2} production, and limestone calcination. Then CO{sub 2} must be compressed into liquid form and transported to the geological sequestration site. Many power plants and other large emitters of CO{sub 2} are located near geological formations that are amenable to CO{sub 2} sequestration.

Xu, Tianfu

2004-11-18

249

Geologic mapping of Vesta  

NASA Astrophysics Data System (ADS)

We report on a preliminary global geologic map of Vesta, based on data from the Dawn spacecraft's High-Altitude Mapping Orbit (HAMO) and informed by Low-Altitude Mapping Orbit (LAMO) data. This map is part of an iterative mapping effort; the geologic map has been refined with each improvement in resolution. Vesta has a heavily-cratered surface, with large craters evident in numerous locations. The south pole is dominated by an impact structure identified before Dawn's arrival. Two large impact structures have been resolved: the younger, larger Rheasilvia structure, and the older, more degraded Veneneia structure. The surface is also characterized by a system of deep, globe-girdling equatorial troughs and ridges, as well as an older system of troughs and ridges to the north. Troughs and ridges are also evident cutting across, and spiraling arcuately from, the Rheasilvia central mound. However, no volcanic features have been unequivocally identified. Vesta can be divided very broadly into three terrains: heavily-cratered terrain; ridge-and-trough terrain (equatorial and northern); and terrain associated with the Rheasilvia crater. Localized features include bright and dark material and ejecta (some defined specifically by color); lobate deposits; and mass-wasting materials. No obvious volcanic features are evident. Stratigraphy of Vesta's geologic units suggests a history in which formation of a primary crust was followed by the formation of impact craters, including Veneneia and the associated Saturnalia Fossae unit. Formation of Rheasilvia followed, along with associated structural deformation that shaped the Divalia Fossae ridge-and-trough unit at the equator. Subsequent impacts and mass wasting events subdued impact craters, rims and portions of ridge-and-trough sets, and formed slumps and landslides, especially within crater floors and along crater rims and scarps. Subsequent to the formation of Rheasilvia, discontinuous low-albedo deposits formed or were emplaced; these lie stratigraphically above the equatorial ridges that likely were formed by Rheasilvia. The last features to be formed were craters with bright rays and other surface mantling deposits. Executed progressively throughout data acquisition, the iterative mapping process provided the team with geologic proto-units in a timely manner. However, interpretation of the resulting map was hampered by the necessity to provide the team with a standard nomenclature and symbology early in the process. With regard to mapping and interpreting units, the mapping process was hindered by the lack of calibrated mineralogic information. Topography and shadow played an important role in discriminating features and terrains, especially in the early stages of data acquisition.

Yingst, R. A.; Mest, S. C.; Berman, D. C.; Garry, W. B.; Williams, D. A.; Buczkowski, D.; Jaumann, R.; Pieters, C. M.; De Sanctis, M. C.; Frigeri, A.; Le Corre, L.; Preusker, F.; Raymond, C. A.; Reddy, V.; Russell, C. T.; Roatsch, T.; Schenk, P. M.

2014-11-01

250

Impact of heterogeneous delays on cluster synchronization  

NASA Astrophysics Data System (ADS)

We investigate cluster synchronization in coupled map networks in the presence of heterogeneous delays. We find that while the parity of heterogeneous delays plays a crucial role in determining the mechanism of cluster formation, the cluster synchronizability of the network gets affected by the amount of heterogeneity. In addition, heterogeneity in delays induces a rich cluster pattern as compared to homogeneous delays. The complete bipartite network stands as an extreme example of this richness, where robust ideal driven clusters observed for the undelayed and homogeneously delayed cases dismantle, yielding versatile cluster patterns as heterogeneity in the delay is introduced. We provide arguments behind this behavior using a Lyapunov function analysis. Furthermore, the interplay between the number of connections in the network and the amount of heterogeneity plays an important role in deciding the cluster formation.

Jalan, Sarika; Singh, Aradhana

2014-10-01

251

Connectivity mapping for flow and transport models in heterogeneous fluvial deposits using lidar and optical imaging  

NASA Astrophysics Data System (ADS)

Connectivity of heterogeneities within fluvial aquifers has a strong influence on groundwater flow and solute transport. Addressing the effects of heterogeneities, popular modeling tools use geostatistical methods that produce multiple realizations faithful to a chosen statistical framework, but usually with minimal correlation or resemblance to real geologic formations. These typically include pixel-based approaches and object-based approaches. More recently applied to this problem, multiple-point approaches have become popular for addressing the heterogeneities and connectivity of the geometries of aquifer facies. This is due to their greater ability to handle the complexities and three-dimensionality of these systems; yet still rely on training images statistically derived from abstract geometries. Taking a step closer to models based on true geological structures, we are developing a measurement approach using ground-based lidar and optical imaging data obtained from extended, rugose outcrops. The varying spatial orientations of these extended outcrops allow the reconstruction of more complete 3D descriptions of the facies. These outcrops provide multiple cross-sections of facies (or realizations) that are continuous through a single geological unit. We use these data to measure the minimum possible extension in 3D space of the high and low transmissivity facies, which characterize the key components of the heterogeneities and their connectivity. That is, for a given facies, using the outcrop data, we are able to identify the lengths of the facies in multiple directions within the extent of the available outcrops; effectively providing a minimum length of the facies in each direction. This yields minimum limits, and in cases where facies terminate, maximum limits on the characteristic lengths of the facies. Where possible, their orientation with respect to the direction of the paleocurrent is also recorded. Because the facies of this particular geological unit may be classified as bimodal, it is reasonable to represent them as either high or low K material. This allows us to develop the model as high K heterogeneities as connected groups of facies that are separated by measurable distances between them through low K material. We are looking at these distances or lengths in multiple orientations, allowing us to construct a model of connectivity that may be related to gradients in any direction. These measurements will be used to provide a real-world geological basis for modeling flow and transport in aquifers.

Soller, M. S.; Weissmann, G. S.; Carritt, J.; Frechette, J. D.

2013-12-01

252

Analysis of 3d complex structure and heterogeneity effects on formation and propagation of regional phases in Eurasia. Final report, 15 August 1992-30 September 1994  

SciTech Connect

This document is the final report for this grant to develop new three-dimensional wave propagation techniques for high frequency waves in heterogeneous media. The report is divided into four sections, each being a published paper sponsored by this grant. In the first section we formulate a one-way wide-angle elastic wave propagation method for arbitrarily heterogeneous media in both the space and wavenumber domains using elastic Rayleigh integrals and local elastic Born scattering theory. In the second section this complex phase screen method is compared with fourth-order finite differences and exact eigenfunction expansion calculations for two-dimensional inhomogeneous media to assess the accuracy of the one-way propagation algorithm. In the third section, an observational study of continental margin structure influence on Lg propagation is presented, using data from the former Soviet stations for nuclear explosions at Novaya Zemlya. We find that bathymetric features can be correlated with energy levels of Lg, suggesting that waveguide structure influences regional phase energy partitioning. This idea is pursued in the fourth section, using Eurasian earthquake and nuclear explosion data along with information about the crustal structure in Eurasia. We develop empirical relations that reduce the scatter in the P/Lg discriminant at low frequency.

Lay, T.; Wu, R.S.

1994-12-13

253

Illinois State Geological Survey  

NSDL National Science Digital Library

The Illinois State Geological Survey (ISGS) homepage provides information on geologic mapping, earthquakes, fossils, groundwater, wetlands, glacial geology, bedrock geology, and Lake Michigan geology. Educational materials include field trip guides, short publications on Illinois geology for students and teachers, online tours, single-page maps, and a geologic column. Other materials include databases and collections of GIS data, well records, drill cores, and mining information; a bibliography of Illinois geology; online maps and data; and information on water and land use, resource development, and geologic hazards.

254

Method of Analysis by the U.S. Geological Survey California District Sacramento Laboratory?Determination of Trihalomethane Formation Potential, Method Validation, and Quality-Control Practices  

USGS Publications Warehouse

An analytical method for the determination of the trihalomethane formation potential of water samples has been developed. The trihalomethane formation potential is measured by dosing samples with chlorine under specified conditions of pH, temperature, incubation time, darkness, and residual-free chlorine, and then analyzing the resulting trihalomethanes by purge and trap/gas chromatography equipped with an electron capture detector. Detailed explanations of the method and quality-control practices are provided. Method validation experiments showed that the trihalomethane formation potential varies as a function of time between sample collection and analysis, residual-free chlorine concentration, method of sample dilution, and the concentration of bromide in the sample.

Crepeau, Kathryn L.; Fram, Miranda S.; Bush, Noel

2004-01-01

255

Geology Fieldnotes: Isle Royale National Park, Michigan  

NSDL National Science Digital Library

This National Park Service (NPS) website examines the geology of Isle Royale National Park in Michigan. It looks at the geologic history of this archipelago, beginning 1.2 billion years ago and progressing through volcanics, rock formations and copper deposits, to the Ice Age. There are links to park maps, visitor information, and additional resources.

256

Historical Geology Online Laboratory Manual  

NSDL National Science Digital Library

The laboratories in this manual cover the following topics: rocks and minerals, weathering of rocks and the formation of sediment, sedimentary rocks and structures, depositional sedimentary environments, sand sieve analysis, relative dating, stratigraphy and lithologic correlation, fossils on the Internet, invertebrate macrofossils, microfossils, preservation, biostratigraphy, evolution, vertebrate paleontology, and interpreting geologic history from maps.

Gore, Pamela

1982-01-01

257

Briefing on geological sequestration (Tulsa)  

EPA Science Inventory

Geological sequestration (GS) is generally recognized as the injection and long-term (e.g., hundreds to thousands of years) trapping of gaseous, liquid or supercritical carbon dioxide (CO2) in subsurface media ? primarily saline formations, depleted or nearly depleted oil and gas...

258

GEOLOGY, January 2008 35 INTRODUCTION  

E-print Network

GEOLOGY, January 2008 35 INTRODUCTION An important component of soil formation is the chemical a variety of methods in noneroding landscapes where the soil age is the time elapsed since the stabilization weathering of primary minerals. In quantifying mineral chemical weathering rates, one approach has been

259

The geologically recent giant impact basins at Vesta's south pole.  

PubMed

Dawn's global mapping of Vesta reveals that its observed south polar depression is composed of two overlapping giant impact features. These large basins provide exceptional windows into impact processes at planetary scales. The youngest, Rheasilvia, is 500 kilometers wide and 19 kilometers deep and finds its nearest morphologic analog among large basins on low-gravity icy satellites. Extensive ejecta deposits occur, but impact melt volume is low, exposing an unusual spiral fracture pattern that is likely related to faulting during uplift and convergence of the basin floor. Rheasilvia obliterated half of another 400-kilometer-wide impact basin, Veneneia. Both basins are unexpectedly young, roughly 1 to 2 billion years, and their formation substantially reset Vestan geology and excavated sufficient volumes of older compositionally heterogeneous crustal material to have created the Vestoids and howardite-eucrite-diogenite meteorites. PMID:22582256

Schenk, Paul; O'Brien, David P; Marchi, Simone; Gaskell, Robert; Preusker, Frank; Roatsch, Thomas; Jaumann, Ralf; Buczkowski, Debra; McCord, Thomas; McSween, Harry Y; Williams, David; Yingst, Aileen; Raymond, Carol; Russell, Chris

2012-05-11

260

The cost of meeting increased cooling-water demands for CO2 capture and storage utilizing non-traditional waters from geologic saline formations  

NASA Astrophysics Data System (ADS)

Deep (> ˜800 m) saline water-bearing formations in the United States have substantial pore volume that is targeted for storage of carbon dioxide (CO2) and the associated saline water can be extracted to increase CO2 storage efficiency, manage pressure build up, and create a new water source that, once treated, can be used for power-plant cooling or other purposes. Extraction, treatment and disposal costs of saline formation water to meet added water demands from CO2 capture and storage (CCS) are discussed. This underutilized water source may be important in meeting new water demand associated with CCS. For a representative natural gas combined-cycle (NGCC) power plant, simultaneous extraction of brine from the storage formation could provide enough water to meet all CCS-related cooling demands for 177 out of the 185 (96 %) saline formations analyzed in this study. Calculated total cost of water extraction, treatment and disposal is less than 4.00 US Dollars (USD) m-3 for 93 % of the 185 formations considered. In 90 % of 185 formations, treated water costs are less than 10.00 USD tonne-1 of CO2 injected. On average, this represents approximately 6 % of the total CO2 capture and injection costs for the NGCC scenario.

Klise, Geoffrey T.; Roach, Jesse D.; Kobos, Peter H.; Heath, Jason E.; Gutierrez, Karen A.

2013-05-01

261

Subsurface geology and porosity distribution, Madison Limestone and underlying formations, Powder River basin, northeastern Wyoming and southeastern Montana and adjacent areas  

USGS Publications Warehouse

To evaluate the Madison Limestone and associated rocks as potential sources for water supplies in the Powder River Basin and adjacent areas, an understanding of the geologic framework of these units, their lithologic facies patterns, the distribution of porosity zones, and the relation between porosity development and stratigraphic facies is necessary. Regionally the Madison is mainly a fossiliferous limestone. However, in broad areas of the eastern Rocky Mountains and western Great Plains, dolomite is a dominant constituent and in places the Madison is almost entirely dolomite. Within these areas maximum porosity development is found and it seems to be related to the coarser crystalline dolomite facies. The porosity development is associated with tabular and fairly continuous crystalline dolomite beds separated by non-porous limestones. The maximum porosity development in the Bighorn Dolomite, as in the Madison, is directly associated with the occurrence of a more coarsely crystalline sucrosic dolomite facies. Well data indicate, however, that where the Bighorn is present in the deeper parts of the Powder River Basin, it may be dominated by a finer crystalline dolomite facies of low porosity. The 'Winnipeg Sandstone' is a clean, generally well-sorted, medium-grained sandstone. It shows good porosity development in parts of the northern Powder River Basin and northwestern South Dakota. Because the sandstone is silica-cemented and quartzitic in areas of deep burial, good porosity is expected only where it is no deeper than a few thousand feet. The Flathead Sandstone is a predominantly quartzose, slightly feldspathic sandstone, commonly cemented with iron oxide. Like the 'Winnipeg Sandstone,' it too is silica-cemented and quartzitic in many places so that its porosity is poor in areas of deep burial. Illustrations in this report show the thickness, percent dolomite, and porosity-feet for the Bighorn Dolomite and the Madison Limestone and its subdivisions. The porosity-feet for the 'Winnipeg' and Flathead Sandstones and four regional geologic sections are also shown.

Peterson, James A.

1978-01-01

262

Biochemical evolution III: Polymerization on organophilic silica-rich surfaces, crystal–chemical modeling, formation of first cells, and geological clues  

PubMed Central

Catalysis at organophilic silica-rich surfaces of zeolites and feldspars might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and other geological sources. Crystal–chemical modeling yielded packings for amino acids neatly encapsulated in 10-ring channels of the molecular sieve silicalite-ZSM-5-(mutinaite). Calculation of binding and activation energies for catalytic assembly into polymers is progressing for a chemical composition with one catalytic Al–OH site per 25 neutral Si tetrahedral sites. Internal channel intersections and external terminations provide special stereochemical features suitable for complex organic species. Polymer migration along nano/micrometer channels of ancient weathered feldspars, plus exploitation of phosphorus and various transition metals in entrapped apatite and other microminerals, might have generated complexes of replicating catalytic biomolecules, leading to primitive cellular organisms. The first cell wall might have been an internal mineral surface, from which the cell developed a protective biological cap emerging into a nutrient-rich “soup.” Ultimately, the biological cap might have expanded into a complete cell wall, allowing mobility and colonization of energy-rich challenging environments. Electron microscopy of honeycomb channels inside weathered feldspars of the Shap granite (northwest England) has revealed modern bacteria, perhaps indicative of Archean ones. All known early rocks were metamorphosed too highly during geologic time to permit simple survival of large-pore zeolites, honeycombed feldspar, and encapsulated species. Possible microscopic clues to the proposed mineral adsorbents/catalysts are discussed for planning of systematic study of black cherts from weakly metamorphosed Archaean sediments. PMID:10097060

Smith, Joseph V.; Arnold, Frederick P.; Parsons, Ian; Lee, Martin R.

1999-01-01

263

Geologic Technician New Curriculum  

ERIC Educational Resources Information Center

Describes a developing two-year geologic technician program at Bakersfield College in which a student may major in five areas - geologic drafting, land and legal, geologic assistant, engineering or paleontology. (RR)

Karp, Stanley E.

1970-01-01

264

Geological Time Scale  

NSDL National Science Digital Library

This document describes how geologic time is approached in discussions of geologic topics. The uses of relative time and absolute time are compared, and a geologic time scale is provided to represent both concepts. References are provided.

265

Applications of TOUGH2 to infiltration of liquids in media with strong heterogeneity  

SciTech Connect

Much hydrogeological research during the last decade has focused on the heterogeneity of natural geologic media on different scales. Most of this work has dealt with flow and transport in single-phase, isothermal conditions. The present paper is concerned with multiphase and nonisothermal flows in strongly heterogeneous media. A primary driver of our studies is the hydrogeological system at Yucca Mountain, which is currently being evaluated by the Department of Energy for its suitability as the site of the first geologic repository for civilian high-level nuclear wastes in the US Yucca Mountain is located in the and Southwest, near the Nevada-California border. Going from large scale to small, formation heterogeneities at Yucca Mountain include (i) alternating tilting layers of welded and non-welded tuffs with different matrix permeability and variable degree of fracturing, (ii) major fault systems, (iii) well-connected and permeable fracture networks in low-permeability rocks, and (iv) individual fractures with highly variable apertures.

Pruess, K.; Antunez, E.

1995-02-01

266

Conversion of geologic quadrangle maps to geologic coverages  

USGS Publications Warehouse

Three hundred sixty-eight geologic map$ of 7-1/2 minute quadrangles in Tennessee were coverted to geographic information system (GIS) coverages. The procedure used was documented and a list was made of the quadrangles included in the coverages. Maps were converted to GIS coverages by making film copies of scribecoats of the maps. The film copies were scanned, vectorized, and written into a generate format. Coverage polygons were tagged with symbels to identify geologic units, and coverage lines were tagged with line types to designate stratigraphic contacts.

Connell, Joseph F.; Barron, William R.; Mitchell, Reavis L.

1994-01-01

267

The conchostracan subgenus Orthestheria (Migransia) from the Tacuarembó Formation (Late Jurassic-?Early Cretaceous, Uruguay) with notes on its geological age  

NASA Astrophysics Data System (ADS)

Conchostracans from the Tacuarembó Formation s.s. of Uruguay are reassigned to the subgenus Orthestheria (Migransia) Chen and Shen. They show more similarities to genera of Late Jurassic age in the Congo Basin and China than to those of Early Cretaceous age. On the basis of the character of the conchostracans, we suggest that the Tacuarembó Formation is unlikely to be older than Late Jurassic. It is probably Kimmeridgian, but an Early Cretaceous age cannot be excluded. This finding is consistent with isotopic dating of the overlying basalts, as well as the age range of recently described fossil freshwater sharks.

Yanbin, Shen; Gallego, Oscar F.; Martínez, Sergio

268

Mineralization and other geologic factors related to the Morrison Formation in particular the northern two-thirds of the Colorado Plateau region; basic data and factor-analysis results  

USGS Publications Warehouse

A vanadium-mercury mineralization factor and five other significant geologic factors were determined by multivariate factor analysis of data for Morrison Formation rock samples from the Colorado Plateau region. The data presented in the report were obtained from an agglomeration of 876 samples which yielded a correlation matrix of 44 variables. The variables consisted of geochemical, petrographic, and geographic location parameters. Mineralization factor scores demonstrate the relative intensity of mineralization in rock samples collected in and around uranium-vanadium ore deposits. The factors affecting composition and texture of the rocks identified from the analysis are: (1) metalliferous mudstones; (2) interstitial carbonate cements; (3) competing sources of different composition; (4) heavy mineral sources; (5) vanadium mineralization; and (6) regional and stratigraphic sampling bias.

Cadigan, Robert Allen

1982-01-01

269

Colorado Geological Survey  

NSDL National Science Digital Library

The Colorado Geological Survey (CGS) is an agency of state government within the Department of Natural Resources whose mission is to help reduce the impact of geologic hazards on the citizens of Colorado, to promote the responsible economic development of mineral and mineral fuel resources, to provide geologic insight into water resources, and to provide geologic advice and information to a variety of constituencies. This site contains extensive information about Colorado geology such as maps, a geologic time scale for the state, program information, and state field trip information. This site hosts the Avalanche Information Center which contains avalanche forecasting and education center details. Publications report on geologic hazards, land use, environmental geology, mineral resources, oil, gas, coal, geologic mapping and earthquake information for the state. There are online editions of RockTalk, which is a quarterly newsletter published by the Colorado Geological Survey dealing with all aspects of geology throughout the state of Colorado. Links are provided for more resources.

270

Ultra-deep oxidation and exotic copper formation at the late pliocene boyongan and bayugo porphyry copper-gold deposits, surigao, philippines: Geology, mineralogy, paleoaltimetry, and their implications for Geologic, physiographic, and tectonic controls  

USGS Publications Warehouse

The Boyongan and Bayugo porphyry copper-gold deposits are part of an emerging belt of intrusion-centered gold-rich deposits in the Surigao district of northeast Mindanao, Philippines. Exhumation and weathering of these Late Pliocene-age deposits has led to the development of the world's deepest known porphyry oxidation profile at Boyongan (600 m), and yet only a modest (30-70 m) oxidation profile at adjacent Bayugo. Debris flows, volcanic rocks, and fluviolacustrine sediments accumulating in the actively extending Mainit graben subsequently covered the deposits and preserved the supergene profiles. At Boyongan and Bayugo, there is a vertical transition from shallower supergene copper oxide minerals (malachite + azurite + cuprite) to deeper sulfide-stable assemblages (chalcocite ?? hypogene sulfides). This transition provides a time-integrated proxy for the position of the water table at the base of the saturated zone during supergene oxidation. Contours of the elevation of the paleopotentiometric surface based on this min- eralogical transition show that the thickest portions of the unsaturated zone coincided with a silt-sand matrix diatreme breccia complex at Boyongan. Within the breccia complex, the thickness of the unsaturated zone approached 600 in, whereas outside the breccia complex (e.g., at Bayugo), the thickness averaged 50 m. Contours of the paleopotentiometric surface suggest that during weathering, groundwater flowed into the breccia complex from the north, south, and east, and exited along a high permeability zone to the west. The high relief (>550 m) on the elevation of the paleopotentiometric surface is consistent with an environment of high topographic relief, and the outflow zone to the west of the breccia complex probably reflects proximity to a steep scarp intersecting the western breccia complex margin. Stable isotope paleoaltimetry has enabled estimation of the elevation of the land surface, which further constrains the physiographic setting during supergene oxidation. Isotopic measurements of oxygen in supergene kaolinite from Boyongan suggest that local paleometeoric water involved in weathering had a ??180 composition of approximately -5.7 per mil. At the latitude of the southern Philippines, this value corresponds to Pleistocene rain water condensing at elevations between 750 and 1,050 m above contemporary sea level, providing a maximum estimate for the surface elevation during weathering of the porphyry systems. Physiographic reconstuctions suggest that the deep oxidation profile at Boyongan formed in an environment of high topographic relief immediately east of a prominent (>550 m) escarpment. The high permeability contrast between the breccia complex and the surrounding wall rocks, coupled with the proximity of the breccia complex to the escarpment, led to a depressed groundwater table and a vertically extensive unsaturated zone in the immediate vicinity of Boyongan. This thick vadose zone and the low hypogene pyrite/copper sulfide ratios (0.6) at Boyongan promoted in situ oxidation of copper sulfides with only modest (<200 m) supergene remobilization of copper. In contrast, higher hypogene pyrite/chalcopyrite ratios (2.3) at Bayugo led to greater acid production during weathering and more complete leaching of copper above the base of oxidation. This process promoted significant (600 m) lateral dispersion of copper down the paleohydraulic gradient into the diatreme breccia comple, ultimately leading to the formation of an exotic copper deposit. ?? 2009 Society of Economices Geologists, Inc.

Braxton, D. P.; Cooke, D. R.; Ignacio, A. M.; Rye, R. O.; Waters, P. J.

2009-01-01

271

The National Park Service: Park Geology  

NSDL National Science Digital Library

A National Park Service (NPS) site primarily composed of three main sections corresponding to the following program areas within the Geologic Resources Division (GRD): Disturbed Lands Restoration and Abandoned Mineral Lands (AML), Mineral Management Programs, and Geology and Soils Programs. Of these, the first two consist principally of textual resources pertaining to Park System procedures, policies, and regulations - as well as reports on example restoration projects with a focus on stream corridor restoration, bioengineering, riparian management, and revegetation. Perhaps of most interest to educators will be the third main program area, the Geology and Soils Programs section. Here are included textual resources pertaining to NPS-GRD programs on cave and karst formations, coastal and shoreline geology, paleontology, soils (e.g., soil biology and soil surveying), geological indicators (geoindicators), and stratigraphy. Lastly, a searchable photographic collection and geologic glossary are available.

272

The Geologic Story of Yosemite Valley  

NSDL National Science Digital Library

This website of the United States Geological Survey (USGS) and the National Park Service (NPS) discusses the geology of Yosemite Valley in California, beginning 100 million years ago with the formation of the granite rocks found in this park and continuing with jointing, exfoliation, and erosion through ice and water. Bedrock Geology includes details about the formation, classification, and descriptions of the plutonic bedrock. It also discusses the relationship of landforms to rock composition and structure and their role in shaping the Yosemite valley.

Huber, N.

273

Phase Transformations in Heterogeneous Steels  

E-print Network

.4 Conclusions 135 References 161 CHAPTER SEVEN ALLOTRIOMORPHIC FERRITE FORMATION IN A HETEROGENEOUS STEEL 7.1 Introduction 163 7.2 Theoretical Analysis 163 7.3 Dilatometry 168 7.4 Conclusions 170 IV References 190 CHAPTER EIGHT COMPLETE CALCULATION... OF MICROSTRUCTURAL EVOLUTION IN HETEROGENEOUS AUTOMOBILE STEELS 8.1 Introduction 191 8.2 Dilatometry 191 8.3 Transformation to bainitic ferrite 194 8.4 Martensitic transformation in 'US83' steel 196 8.5 Conclusions 197 References 229 CHAPTER NINE SUMMARY AND FURTHER...

Khan, Shahid Amin

1990-05-08

274

Unraveling Geological History: Glaciers and Faults at Discovery Park, Seattle  

NSDL National Science Digital Library

This introductory geology field exercise asks students to make individual observations about parts of an outcrop, then combine their observations in larger teams to interpret the overall geological history of the exposure. Content learning includes stratigraphy, faulting, and local geologic history; process learning includes data gathering and recording, hypothesis formation, and outlining helpful evidence that could be gathered in the future.

Tucker, Trileigh

275

Geology Fieldnotes: Sleeping Bear Dunes National Lakeshore, Michigan  

NSDL National Science Digital Library

The Sleeping Bear Dunes National Lakeshore site contains park geology information, park maps, photographs, related links, and visitor information. The park geology section discusses the geologic history of the region and formation of Sleeping Bear Dunes through westerly winds from Lake Michigan. The park maps section includes a map of the Sleeping Bear Dunes National Lakeshore and the surrounding area.

276

Spatial and temporal relations between early Tertiary shortening and extension in NW Washington, based on geology of the Pipestone Canyon Formation and surrounding rocks  

Microsoft Academic Search

Detailed mapping of the deformed Paleocene Pipestone Canyon Formation and surrounding Cretaceous rocks in NW Washington suggests that uplift, erosion, and unroofing of adjacent rocks was influenced by shortening at high angle to the continental margin during mid-Cretaceous (circa 88-110 Ma) and early Tertiary (47-65 Ma) time. Although significant shortening is mid-Cretaceous in age, additional shortening, expressed as reverse faults

Bryan J. Kriens; Diane L. Hawley; F. Duke Chappelear; Peter D. Mack; Ahn F. Chan

1995-01-01

277

Spatial and temporal relations between early Tertiary shortening and extension in NW Washington, based on geology of the Pipestone Canyon Formation and surrounding rocks  

Microsoft Academic Search

Detailed mapping of the deformed Paleocene Pipestone Canyon Formation and surrounding Cretaceous rocks in NW Washington suggests that uplift, erosion, and unroofing of adjacent rocks was influenced by shortening at high angle to the continental margin during mid-Cretaceous (circa 88–110 Ma) and early Tertiary (47–65 Ma) time. Although significant shortening is mid-Cretaceous in age, additional shortening, expressed as reverse faults

Bryan J. Kriens; Diane L. Hawley; F. Duke Chappelear; Peter D. Mack; Ahn F. Chan

1995-01-01

278

Maryland Geological Survey  

NSDL National Science Digital Library

The Maryland Geological Survey (MGS) homepage contains information from MGS programs on hydrogeology, hydrology, coastal and estuarine geology, environmental geology and mineral resources; an online guide to Maryland geology; and information on oyster habitat restoration projects. There are also maps, data, information on MGS publications, MGS news, and online educational resources.

279

Freshwater-Saltwater Interface Configuration in a Heterogeneous Fractured Aquifer, Saturna Island, BC, Canada  

NASA Astrophysics Data System (ADS)

In coastal aquifers, heterogeneity due to variable fracturing introduces complexity to the configuration of the saltwater wedge and to chemical transport in the vicinity of the fresh water-salt water interfaces. Field geologic and structural mapping studies, in combination with the analysis of pumping tests and numerical simulations of flow and transport provide insight into the complexity of groundwater flow on the Gulf Islands in southwestern British Columbia, Canada. The islands consist of an alternating sequence of sandstone-dominant and mudstone-dominant formations, which were extensively fractured during numerous tectonic events. In contrast to typical layered porous media sedimentary aquifer systems, fine-grained rocks exhibit denser fracturing compared to coarse-grained rocks, and thus, mudstone-dominant layers and interbeds are thought to act as primary water-bearing units. Numerous pumping tests conducted in water supply wells suggest an equivalent porous media approach may be valid for representing permeability at a regional scale. A range of hydraulic conductivity (permeability) values was estimated for different geologic formations. These values were used as input in a series of models that reflect the heterogeneity of the aquifer owing to the variable fracturing of the layered aquifer system. Simulations were carried out using USGS SUTRA. Models simulations indicate that the magnitude of the permeability and the nature of layering exercise a major control of the magnitude and appearance of the freshwater-saltwater interface.

Liteanu, E.; Allen, D. M.

2003-12-01

280

Mantle Heterogeneity: What is the message from geochemistry?  

NASA Astrophysics Data System (ADS)

Ubiquitous heterogeneity in the Earth's mantle has been documented by numerous chemical and isotopic analyses of oceanic basalts. Despite about four decades of research and the continuously increasing number of data, however, the way in which compositional heterogeneity is manifest in the Earth's mantle, as well as the origin and processes leading to mantle heterogeneity remain fundamental questions. A statistical analysis of the large amount of available isotope data in oceanic basalts shows that two principal compositional vectors capture about 95% of the isotopic variation. Care must be taken, however, to directly equate basalt and mantle isotopic composition, because partial melting, and melt mixing during melt extraction lead to a biased representation and subdued compositional variability in the basalts compared to their mantle sources. This is perhaps best documented by the isotopic disparity between MORB and abyssal peridotites, which are isotopically by far more depleted and variable than MORB. In contrast, enriched isotope signatures in ocean island basalts (OIB) closely represent those of their average enriched mantle source components. The main principal vector of the MORB and OIB isotopic distribution (about two-thirds of the variation) corresponds to the generation and subduction of oceanic plates. Mass exchange between the lower and upper continental crust and the mantle accounts for most of the remaining third of the MORB-OIB isotopic variation. This simple conceptual framework attributes mantle heterogeneity mainly to the large-scale cycling between the Earth's two major lithophile element reservoirs, the mantle and the oceanic and continental crust. Formation and evolution of mantle heterogeneity is therefore a continuous process that is largely governed by plate-tectonic processes, and unlikely to result in just a few large-scale mantle reservoirs, which subsequently interact and mingle during intra-mantle processing. To what extent heterogeneous mantle materials preserve their inherent compositional heterogeneity depends on the physics and fluid dynamics of the mantle. Once formed, by continuous depletion through partial melting (depleted mantle) and by transport into the mantle, heterogeneous materials become stretched, reduced in size and at present, they are more or less statistically distributed. Large-scale statistical differences caused by differences in the relative abundance of the distinct mantle materials may result in large-scale compositional "domains" (e.g. DUPAL or SOPITA ). Alternatively these putative domains could be an artifact resulting from different sampling of a similar population of mantle components. At mid-ocean ridges, for example, the observed degree of isotopic variability decreases as the scale of melting, or rate of processing of mantle material (as measured by the spreading rate), increases. This observation also shows that the scale of mantle components is small compared to the maximum dimension over which melts are produced and mixed beneath ridges, i.e. certainly on the kilometer scale of the melting region but perhaps even smaller. Further support for this sub-kilometer scale of mantle heterogeneity comes from theoretical melting models, the depth-dependent sampling of isotopically distinct source materials observed in Icelandic basalts, the isotopic heterogeneity observed in melt inclusions, and the sub-kilometer scale isotopic heterogeneity observed in abyssal peridotites. These observations further show that, despite intra-mantle processing by convective stirring, both enriched and highly depleted isotopic materials survive, i.e. to a large extent they retain their physico-chemical integrity, and escape equilibration with ambient, compositionally distinct material over geologic timescales (> 1 Ga).

Stracke, Andreas

2010-05-01

281

Tennessee Division of Geology  

NSDL National Science Digital Library

This is the homepage of the Geology Division of the Tennessee Department of Environment and Conservation. It provides information on the division's programs, including geologic hazards research, public service, education programs, basic and applied research on geology and mineral resources, publication of geologic information, permitting of oil and gas wells, and regulation of Tennessee's oil and gas industry. Materials include a catalog of publications, maps, geologic bulletins, and the Public Information series of pamphlets; the Geology Division Newsletter; and information on the state's mineral industry. There is also a section on the Gray Fossil Site, an unusual assemblage of fossils and sedimentary geology encountered during road construction near the town of Gray, Tenessee.

282

Venus geology  

NASA Technical Reports Server (NTRS)

The Magellan mission to Venus is reviewed. The scientific investigations conducted by 243-day cycles encompass mapping with a constant incidence angle for the radar, observing surface changes from one cycle to the next, and targeting young-looking volcanos. The topography of Venus is defined by the upper boundary of the crust and upwelling from lower domains. Tectonic features such as rift zones, linear mountain belts, ridge belts, and tesserae are described. The zones of tesserae are unique to the planet. Volcanism accounts for about 80 percent of the observed surface, the remainder being volcanic deposits which have been reworked by tectonism or impacts. Magellan data reveal about 900 impact craters with flow-like ejecta resulting from the fall of meteoroids. It is concluded that the age of the Venusian surface varies between 0 and 800 million years. Tectonic and volcanic activities dominate the formation of the Venus topography; such processes as weathering and erosion are relatively unimportant on Venus.

Mclaughlin, W. I.

1991-01-01

283

Estimation of the hydraulic parameters of a confined geologic formation from slug test in fully penetrating well using a complete quasi-steady flow model in a forward and in an inverse optimal estimation procedure  

NASA Astrophysics Data System (ADS)

Slug tests offer a fast and inexpensive means of estimating the hydraulic parameters of a geologic formation, and are very well suited for contaminated site assessment because no water is essentially withdrawn. In the great majority of slug tests performed in wells fully penetrating confined geologic formations, and for over-damped conditions, the response data are evaluated with the transient-flow model of Cooper et al. (1967) when the radial hydraulic conductivity Kr and the coefficient of specific storage Ss are to be estimated. That particular analytical solution, however, is computationally involved and awkward to use. Thus, groundwater professionals often use a few pre-prepared type-curves to fit the data by a rough matching procedure, visually or computationally. On the other hand, the method of Hvorslev (1951), which assumes the flow to be quasi-steady, is much simpler but yields only Kr-estimates. Koussis and Akylas (2012) have derived a complete quasi-steady flow model that includes a storage balance inside the aquifer and allows estimating both Kr and Ss, through matching of the well response data to a (dimensionless) type-curve. That model approximates the model of Cooper et al. closely and has the practical advantage that its solution type-curves are generated very simply, even using an electronic spreadsheet. Thus, an optimal fit of data by a type-curve can be readily embedded in an exhaustive search. That forward procedure, however, is semi-automated; it involves repeated computation of the quasi-steady flow solution, until finding an optimal pair of Kr and Ss values, according to some formal criterion of optimality, or visually. In addition, we have developed a fully automated inverse procedure for estimating the optimal hydraulic formation parameters Kr and Ss. We test and compare these two parameter estimation methods for the slug test and discuss their strengths and weaknesses. Cooper, H. H., Jr., J. D. Bredehoeft and I. S. Papadopulos. 1967. Response of a finite-diameter well to an instantaneous charge of water, Water Resour. Res., 3(1): 263-269. Koussis A. D. and E. Akylas (2012) Slug test analysis for confined aquifers in the over-damped case: Quasi-steady flow model, with estimation of the specific storage coefficient, Ground Water, 50(4): 608-613.

Rozos, Evangelos; Akylas, Evangelos; Koussis, Antonis D.

2013-04-01

284

Geology, coal resources, and chemical analyses of coal from the Fruitland Formation, Kimbeto EMRIA study site, San Juan County, New Mexico  

USGS Publications Warehouse

The Kimbeto EMRIA study site, an area of about 20 square miles (52 km2), is located on the south margin of the San Juan Basin on the gently northward-dipping strata of the Upper Cretaceous Fruitland Formation and the Kirtland Shale. The coal beds are mainly in the lower 150 feet (45 m) of the Fruitland Format ion. Coal resources--measured, indicated, and inferred--with less than 400 feet (120 m) of overburden in the site are 69,085,000 short tons (62,660,100 metric tons), 369,078,000 short tons (334,754,000 metric tons), and 177,803,000 short tons (161,267,000 metric tons) respectively. About 68 percent of these resources are overlain by 200 feet (60 m) or less of overburden. The apparent rank of the coal ranges from subbituminous B to subbituminous A. The average Btu/lb value of 14 core samples from the site on the as-received basis is 8,240 (4580 Kcal/kg), average ash content is 23.4 percent, and average sulfur content is 0.5 percent. Analyses of coal from the Kimbeto EMRIA study site show significantly higher ash content and significantly lower contents of volatile matter, fixed carbon, carbon, and a significantly lower heat of combustion when compared with other coal analyses from the Rocky Mountain province.

Schneider, Gary B.; Hildebrand, Rick T.; Affolter, Ronald H.

1979-01-01

285

Spatial and temporal relations between early Tertiary shortening and extension in NW Washington, based on geology of the Pipestone Canyon Formation and surrounding rocks  

NASA Astrophysics Data System (ADS)

Detailed mapping of the deformed Paleocene Pipestone Canyon Formation and surrounding Cretaceous rocks in NW Washington suggests that uplift, erosion, and unroofing of adjacent rocks was influenced by shortening at high angle to the continental margin during mid-Cretaceous (circa 88-110 Ma) and early Tertiary (47-65 Ma) time. Although significant shortening is mid-Cretaceous in age, additional shortening, expressed as reverse faults and major folds, is early Tertiary. In the map area and regions to the west and northwest (the Skagit-Methow-western Okanogan area), the shortening is essentially unmodified by extensional deformation, whereas in regions east and northeast of the map area (the Omineca and eastern Okanogan regions), widespread Eocene extension has obscured the shortening and caused additional unroofing as well. The conglomeratic Pipestone Canyon Formation lies unconformably on intruded Early Cretaceous rocks of the lower Methow sequence. Approximately 3-5 km of mid-Cretaceous Methow sequence strata are missing at the unconformity yet are present 15 km to the west and northwest. These observations indicate Late Cretaceous erosion and unroofing in the southeastern Methow area prior to deposition of the Pipestone Canyon Formation. Furthermore, conglomerate clasts in the Pipestone Canyon Formation record sources resulting from relative uplift of the crystalline Okanogan Complex east of the basin and, slightly later, from relative uplift of the volcano-sedimentary Methow sequence and structurally underlying migmatitic Skagit Complex west to northwest of the basin. Following deposition, which ended sometime between 55 and 65 Ma, the Pipestone Canyon Formation and underlying Methow sequence were tightly folded and faulted and juxtaposed with the Okanogan Complex by reverse faulting. The map pattern of these folds and faults suggests ENE-WSW shortening and concomitant uplift. Crosscutting relations north of the map area constrain this deformation to be pre-47 Ma. Similarity of Pipestone Canyon fold geometry to folds elsewhere in the Methow and Skagit areas supports the interpretation that a significant fold belt of circa 47-65 Ma age developed in these areas and overprinted the mid-Cretaceous folding and thrusting. Regional data suggest the circa 47-65 Ma folding formed a synclinorium in the Methow area and an anticlinorium in the Skagit area, roughly concurrent with cooling ages for deep (8-9 kbar) Skagit rocks. For the Skagit-Methow-western Okanogan region as a whole, the 47-65 Ma shortening and unroofing were accompanied by uncertain amounts of fold belt-parallel strike-slip faulting. Timing estimates for shortening in the Skagit-Methow-western Okanogan area are generally older but overlap with those established for extension farther east and northeast in the Okanogan Complex and Omineca Belt, supporting interpretations that the belt of extension began to develop during or very soon after regional shortening. Existing thermal rheological models of extension immediately after shortening point to the need for heat sources other than mantle conduction and crustal radioactivity to facilitate the extension. Apparently, the Skagit-Methow fold belt failed to extend because it lacked the necessary heat.

Kriens, Bryan J.; Hawley, Diane L.; Chappelear, F. Duke; Mack, Peter D.; Chan, Ahn F.

1995-06-01

286

Essentials of Geology  

NSDL National Science Digital Library

From subduction to the world of hot spot volcanoes, this online resource for students and teachers of geology will please users with its fun and useful animations, crossword puzzles, and well-written articles. The site was designed to complement a textbook created by W.W. Norton, but many of the materials can be used as stand-alone exercises. Visitors will want to begin by looking through the visually enticing animations, which cover the Earth's magnetic field, the spread of the sea floor, and the formation of ocean crust. All told, there are over sixty animations, and teachers may wish to recommend them to students. Additionally, visitors should note that they can also browse through the materials offered on the site by clicking on the chapter listings located near the top of the screen. It's hard to pass up a crossword puzzle, and visitors may find themselves spending more time there than at any other part of the site.

Marshak, Stephen

2008-02-18

287

Godiva Rim Member: A new stratigraphic unit of the Green River Formation in southwest Wyoming and northwest Colorado. Geology of the Eocene Wasatch, Green River, and Bridger (Washakie) Formations, Greater Green River Basin, Wyoming, Utah, and Colorado. Professional paper  

SciTech Connect

The report names and describes the Godiva Rim Member of the Green River Formation in the eastern part of the Washakie basin in southwest Wyoming and the central part of the Sand Wash basin in northwest Colorado. The Godiva Rim Member comprises lithofacies of mixed mudflat and lacustrine origin situated between the overlying lacustrine Laney Member of the Green River Formation and the underlying fluvial Cathedral Bluffs Tongue of the Wasatch Formation. The Godiva Rim Member is laterally equivalent to and grades westward into the LaClede Bed of the Laney Member. The Godiva Rim Member of the Green River Formation was deposited along the southeast margins of Lake Gosiute and is correlated to similar lithologic units that were deposited along the northeast margins of Lake Uinta in the Parachute Creek Member of the Green River Formation. The stratigraphic data presented provide significant evidence that the two lakes were periodically connected around the east end of the Uinta Mountains during the middle Eocene.

Roehler, H.W.

1991-01-01

288

SIMULATION MODEL ANALYSIS OF THE MOST PROMISING GEOLOGIC SEQUESTRATION FORMATION CANDIDATES IN THE ROCKY MOUNTAIN REGION, USA, WITH FOCUS ON UNCERTAINTY ASSESSMENT  

SciTech Connect

The purpose of this report is to report results of reservoir model simulation analyses for forecasting subsurface CO2 storage capacity estimation for the most promising formations in the Rocky Mountain region of the USA. A particular emphasis of this project was to assess uncertainty of the simulation-based forecasts. Results illustrate how local-scale data, including well information, number of wells, and location of wells, affect storage capacity estimates and what degree of well density (number of wells over a fixed area) may be required to estimate capacity within a specified degree of confidence. A major outcome of this work was development of a new workflow of simulation analysis, accommodating the addition of “random pseudo wells” to represent virtual characterization wells.

Lee, Si-Yong; Zaluski, Wade; Will, Robert; Eisinger, Chris; Matthews, Vince; McPherson, Brian

2013-09-01

289

Depositional and diagenetic history and petroleum geology of the Jurassic Norphlet Formation of the Alabama coastal waters area and adjacent federal waters area  

USGS Publications Warehouse

The discovery of deep (>20,000 ft) gas reservoirs in eolian sandstone of the Upper Jurassic Norphlet Formation in Mobile Bay and offshore Alabama in the late 1970s represents one of the most significant hydrocarbon discoveries in the nation during the past several decades. Estimated original proved gas from Norphlet reservoirs in the Alabama coastal waters and adjacent federal waters is 7.462 trillion ft3 (Tcf) (75% recovery factor). Fifteen fields have been established in the offshore Alabama area. Norphlet sediment was deposited in an arid environment in alluvial fans, alluvial plains, and wadis in updip areas. In downdip areas, the Norphlet was deposited in a broad desert plain, with erg development in some areas. Marine transgression, near the end of Norphlet deposition, resulted in reworking of the upper part of the Norphlet Formation. Norphlet reservoir sandstone is arkose and subarkose, consisting of a simple assemblage of three minerals, quartz, albite, and K-feldspar. The present framework grain assemblage of the Norphlet is dominantly diagenetic, owing to albitization and dissolution of feldspar. Despite the simple framework composition, the diagenetic character of the Norphlet is complex. Important authigenic minerals include carbonate phases (calcite, dolomite, Fe-dolomite, and breunnerite), feldspar (albite and K-feldspar), evaporite minerals (anhydrite and halite), clay minerals (illite and chlorite), quartz, and pyrobitumen. The abundance and distribution of these minerals varies significantly between onshore and offshore regions of Norphlet production. The lack of sufficient internal sources of components for authigenic minerals, combined with unusual chemical compositions of chloride (Mg-rich), breunnerite, and some minor authigenic minerals, suggests that Louann-derived fluids influenced Norphlet diagenesis. In offshore Alabama reservoirs, porosity is dominantly modified primary porosity. Preservation of porosity in deep Norphlet reservoirs is due to a combination of factors, including a lack of sources of cement components and lack of pervasive early cement, so that fluid-flow pathways remained open during burial. Below the dominantly quartz-cemented tight zone near the top of the Norphlet, pyrobitumen is a major contributor to reduction in reservoir quality in offshore Alabama. The highest reservoir quality occurs in those wells where the present gas-water contact is below the paleohydrocarbon-water contact. Thiz zone of highest reservoir quality is between the lowermost occurrence of pyrobitumen and the present gas-water contact.The Upper Jurassic Norphlet Formation sediment was deposited in an arid environment in alluvial fans, alluvial plains, and wadis in undip areas. In downdip areas, the Norphlet was deposited in a broad desert plain, with erg development in some areas. Marine transgression, near the end of Norphlet deposition resulted in reworking of the upper part of the formation. he present framework grain assemblage of the Norphlet is dominantly diagenetic, owing to albitization and dissolution of feldspar. Despite the simple framework composition, the diagenetic character of the Norphlet is complex.

Kugler, R. L.; Mink, R. M.

1999-01-01

290

The Geology of Vesta  

NASA Astrophysics Data System (ADS)

The Dawn spacecraft collected over 28,000 images and a wealth of spectral data of Vesta's surface. These data enable analysis of Vesta's diverse geology including impact craters of all sizes and unusual shapes, a variety of ejecta blankets, large troughs, impact basins, enigmatic dark material, and considerable evidence for mass wasting and surface alteration processes [1,2,3]. Two large impact basins, Veneneia underlying the larger Rheasilvia basin dominate the south polar region [1,4]. The depression surrounding Vesta's south pole was formed by two giant impacts about one billion and two billion years ago [4,5]. Vesta's global tectonic patterns (two distinct sets of large troughs orthogonal to the axes of the impacts) strongly correlate with the locations of the two south polar impact basins, and were likely created by their formation [1,6]. Numerous unusual asymmetric impact craters and ejecta indicate the strong influence of topographic slope in cratering on Vesta [1]. One type of gully in crater walls is interpreted to form by dry granular flow, but another type is consistent with transient water flow [7]. Very steep topographic slopes near to the angle of repose are common; slope failures make resurfacing due to impacts and their associated gravitational slumping and seismic effects an important geologic process on Vesta [1]. Clusters of pits in combination with impact melt [8] suggest the presence of volatile materials underlying that melt in some crater floors. Relatively dark material of uncertain origin is intermixed in the regolith layers and partially excavated by younger impacts yielding dark outcrops, rays and ejecta [1,9]. Vesta's surface is reworked by intense impacts and thus much younger than the formation of its crust [2,5].

Jaumann, R.; Russell, C. T.; Raymond, C. A.; Pieters, C. M.; Yingst, R. A.; Williams, D. A.; Buczkowski, D. L.; Krohn, K.; Otto, K.; Stephan, K.; DeSanctis, M. C.; Garry, W. B.; Blewett, D.

2013-09-01

291

Geoscience\\/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico-stratigraphic hierarchy and cycle stacking facies distribution, and interwell-scale heterogeneity: Grayburg Formation, New Mexico. Final report  

Microsoft Academic Search

The Grayburg Formation (middle Guadalupian) is a major producing interval in the Permian Basin and has yielded more than 2.5 billion barrels of oil in West Texas. Grayburg reservoirs have produced, on average, less than 30 percent of their original oil in place and are undergoing secondary and tertiary recovery. Efficient design of such enhanced recovery programs dictates improved geological

R. J. Barnaby; W. B. Ward; J. W. Jr. Jennings

1997-01-01

292

Geology Fieldnotes: Wind Cave National Park South Dakota  

NSDL National Science Digital Library

Wind Cave National Park includes one of the world's longest and most complex caves and 28,295 acres of mixed-grass prairie, ponderosa pine forest, and associated wildlife. The cave is well known for its outstanding display of boxwork, an unusual cave formation composed of thin calcite fins resembling honeycombs. Features include park geology information, maps, photographs of cave formations, related links, and visitor information. The park geology section discusses geologic history, structural geology, cave formations, and history of exploration of the region. The park maps section includes an area map of Wind Cave National Park and a detailed cave map.

293

Modeling geologic storage of carbon dioxide: Comparison ofnon-hysteretic and hysteretic characteristic curves  

SciTech Connect

Numerical models of geologic storage of carbon dioxide (CO2)in brine-bearing formations use characteristic curves to represent theinteractions of non-wetting-phase CO2 and wetting-phase brine. When aproblem includes both injection of CO2 (a drainage process) and itssubsequent post-injection evolution (a combination of drainage andwetting), hysteretic characteristic curves are required to correctlycapture the behavior of the CO2 plume. In the hysteretic formulation,capillary pressure and relative permeability depend not only on thecurrent grid-block saturation, but also on the history of the saturationin the grid block. For a problem that involves only drainage or onlywetting, a non-hysteretic formulation, in which capillary pressure andrelative permeability depend only on the current value of the grid-blocksaturation, is adequate. For the hysteretic formulation to be robustcomputationally, care must be taken to ensure the differentiability ofthe characteristic curves both within and beyond the turning-pointsaturations where transitions between branches of the curves occur. Twoexample problems involving geologic CO2 storage are simulated withTOUGH2, a multiphase, multicomponent code for flow and transport codethrough geological media. Both non-hysteretic and hysteretic formulationsare used, to illustrate the applicability and limitations ofnon-hysteretic methods.The first application considers leakage of CO2from the storage formation to the ground surface, while the secondexamines the role of heterogeneity within the storageformation.

Doughty, Christine

2006-07-17

294

Inner thermal resonance in thermoelastic geological structures  

NASA Astrophysics Data System (ADS)

When investigating heterogeneous media such as composite materials or geological structures, it is convenient to replace them by macroscopic equivalent media, which simplifies computations a lot. In the paper, we look for the equivalent macroscopic model for describing seismic wave propagation and transient heat transfers in thermoelastic periodic geological structures made of rock or soil. We follow the route described in Auriault (2012), to investigating thermoelastic composite media. We use the method of multi-scale asymptotic expansions. By estimating the dimensionless numbers in the momentum and energy balances, we show that an equivalent macroscopic model exists for describing seismic waves at very low frequencies only. The model then shows a damping which is due to thermal resonance at the heterogeneity scale. At higher frequencies, such an equivalent macroscopic model does not exist. Macroscopic models for describing transient heat transfers do not exist.

Auriault, Jean-Louis

2014-10-01

295

Glossary of Geologic Terms  

NSDL National Science Digital Library

This page from Iowa State University presents a general glossary of geologic terms. The site would be a good reference for geology coursework. This glossary of geologic terms is based on the glossary in Earth: An Introduction to Geologic Change, by S. Judson and S.M. Richardson (Englewood Cliffs, NJ, Prentice Hall, 1995). Where possible, definitions conform generally, and in some cases specifically, to definitions given in Robert L Bates and Julia A Jackson (editors), Glossary of Geology, 3rd ed., American Geological Institute, Alexandria, Virginia, 1987.

2011-07-18

296

SEISMIC DETERMINATION OF RESERVOIR HETEROGENEITY; APPLICATION TO THE CHARACTERIZATION OF HEAVY OIL RESERVOIRS  

SciTech Connect

The objective of the project is to examine how seismic and geologic data can be used to improve characterization of small-scale heterogeneity and their parameterization in reservoir models. The study is performed at West Coalinga Field in California. We continued our investigation on the nature of seismic reactions from heterogeneous reservoirs. We began testing our algorithm to infer parameters of object-based reservoir models from seismic data. We began integration of seismic and geologic data to determine the deterministic limits of conventional seismic data interpretation. Lastly, we began integration of seismic and geologic heterogeneity using stochastic models conditioned both on wireline and seismic data.

Matthias G. Imhof; James W. Castle

2003-11-01

297

Marine geology: A planet earth perspective  

SciTech Connect

This text provides coverage of the basic geology of the marine development. It starts with the formation of the oceans using plate tectonics, continues with discussions of the mid-ocean ridges, and concludes with coverage of the formation and deformation of the continents.

Anderson, R.N.

1986-01-01

298

Geology Fieldnotes: Acadia National Park, Maine  

NSDL National Science Digital Library

This National Park Service website highlights the geology of Acadia National Park. The story begins 500 million years ago, and goes through rock cycles, formations (Ellsworth, Bar Harbor, and Cranberry formations), intrusions, the Ice Age, glacial features, and development of shore patterns. There are area and park maps, photos, and links to additional information.

299

Horse Evolution Geology 331Geology 331  

E-print Network

Horse Evolution Geology 331Geology 331 Paleontology #12;Horses #12;Equus caballus #12;#12;Equus;EquusMerychippusMiohippusHyracotherium Hind feet left, front feet right. #12;Hyracotherium or Eohippus;MerychippusMerychippus from the MioceneMiocene, a plains grazer #12;The modern horseThe modern horse Equus

Kammer, Thomas

300

Geology Major www.geology.pitt.edu/undergraduate/geology.html  

E-print Network

, including the quality of air, water, and soil. Geology majors have hiked the Appalachian Trail, gone of GEOL at the 1000 level or above. Chemistry requirements CHEM 0110 General Chemistry 1 CHEM 0120 General

Jiang, Huiqiang

301

GSA Geologic Time Scale  

NSDL National Science Digital Library

This Geological Society of America (GSA) site contains a detailed geologic time scale as an educational resource. It may be downloaded to a larger size, and includes all Eras, Eons, Periods, Epochs and ages as well as magnetic polarity information.

1999-01-01

302

Geophysics & Geology Inspected.  

ERIC Educational Resources Information Center

Summarizes findings of a recently published report of the Canadian Geoscience Council, which includes the following topics regarding college geology: facilities; teaching; undergraduate enrollments; postgraduate enrollments; geologic research; and integration of Canadian geoscience with other countries. (CS)

Neale, E. R. W.

1981-01-01

303

Significant achievements in the Planetary Geology Program. [geologic processes, comparative planetology, and solar system evolution  

NASA Technical Reports Server (NTRS)

Developments reported at a meeting of principal investigators for NASA's planetology geology program are summarized. Topics covered include: constraints on solar system formation; asteriods, comets, and satellites; constraints on planetary interiors; volatiles and regoliths; instrument development techniques; planetary cartography; geological and geochemical constraints on planetary evolution; fluvial processes and channel formation; volcanic processes; Eolian processes; radar studies of planetary surfaces; cratering as a process, landform, and dating method; and the Tharsis region of Mars. Activities at a planetary geology field conference on Eolian processes are reported and techniques recommended for the presentation and analysis of crater size-frequency data are included.

Head, J. W. (editor)

1978-01-01

304

Volcanic geology of Tyrrhena Patera, Mars  

NASA Astrophysics Data System (ADS)

Consideration is given to the geology of Tyrrhena Patera, a large low-relief volcano in the southern cratered highlands of Mars. The general geology of Tyrrhena Patera is outlined and models for the formation of the volcano are described. Models derived from studies of terrestrial pyroclastic flows are applied to deposits at Tyrrhena Patera, showing that the characteristics of the deposits are consistent with an origin by the emplacement of gravity-driven ash flows generated by hydromagmatic or magmatic explosive eruptions.

Greeley, R.; Crown, D. A.

1990-05-01

305

REMOTE SENSING GEOLOGICAL SURVEY  

E-print Network

/Enhanced Thematic Mapper) Imagery Collection Examples of sensors used in CPRM geologic projects Geological Survey for ground water in crystalline terrain 3(VIS)4(NIR)5(SWIR) Moji and Pardo Rivers Basin ­ São Paulo State 3 and Reflection Radiometer) Imagery Collection in CPRM Examples of sensors used in the CPRM geologic projects #12

306

Glossary of Geology  

Microsoft Academic Search

The Glossary has expanded coverage particularly in such active fields as carbonate sedimentology, environmental geology and geophysics, GIS, GPS, hydrology and hydraulics, marine and coastal geology, organic geochemistry, paleoecology, seismology, stratigraphic nomenclature, speleology and karst, and structural geology and tectonics. Many definitions provide a syllabification guide and background information. Thus a reader will learn the difference between look-alike pairs, such

Julia A. Jackson

2005-01-01

307

Geology of Death Valley National Park  

NSDL National Science Digital Library

This site of the United States Geologic Survey (USGS) and the National Park Service (NPS) highlights the geologic history of Death Valley National Park in Nevada and California. The story begins 1.8 billion years ago with the formation of rocks and continues through uplift, faulting, volcanism, early animals of the area, glaciers, and the making of deserts and dunes. A geologic timescale connects to specific events in the history of Death Valley. There are topographic maps of the area, a field trip of the park, an image gallery, and technical papers available to download.

308

OneGeology: Making the World’s Geological Map Data Accessible Online  

NASA Astrophysics Data System (ADS)

OneGeology (http://onegeology.org) is a successful international initiative of the geological surveys of the world and the flagship project of the ‘International Year of Planet Earth’. Its aim is to provide dynamic web access to geological map data covering the world, creating a focus for accessing geological information for everyone. Thanks to the enthusiasm and support of participating nations the initiative has progressed rapidly and geological surveys and the many users of their data are excited about this ground-breaking project. Currently 10 international geoscience organizations have endorsed the initiative and more than 109 countries have agreed to participate. OneGeology works with whatever digital format is available in each country. The target scale is 1:1 million, but the project is pragmatic and accepts a range of scales and the best available data. The initiative recognizes that different nations have differing abilities to participate and transfer of know-how to those who need it is a key aspect of the approach. A key contributor to the success of OneGeology has been its utilization of the latest new web technology and an emerging data exchange standard for geological map data called GeoSciML. GeoSciML (GeoScience Markup Language) is a schema written in GML (Geography Markup Language) for geological data. GeoSciML has the ability to represent both the geography (geometries e.g. polygons, lines and points) and geological attribution in a clear and structured format. OneGeology was launched March 2007 at the inaugural workshop in Brighton England. At that workshop the 43 participating nations developed a declaration of a common objective and principles called the “Brighton Accord” (http://onegeology.org/what_is/accord.html) . Work was initiated immediately and the resulting OneGeology Portal was launched at the International Geological Congress in Oslo in August 2008 by Simon Winchester, author of “The Map that Changed the World”. Since the successful launch, OneGeology participants have continued working both to increase national participation and content, and to put in place a more formal governance structure to oversee the long term evolution of the initiative. OneGeology is an example of collaboration in action and is both multilateral and multinational. In 2007, a group of motivated geoscientists and data managers identified an opportunity and took the initiative to engage their peers to work in concert to achieve a shared objective. OneGeology has facilitated collaborative development of an Internet site that provides unprecedented online access to global geological map data.

Broome, H.; Jackson, I.; Robida, F.; Thorleifson, H.

2009-12-01

309

Vesta: A Geological Overview  

NASA Astrophysics Data System (ADS)

The Dawn spacecraft has collected over 28,000 images and a wealth of spectral data providing nearly complete coverage of Vesta’s surface with multiple views. These data enable analysis of Vesta’s diverse geology including impact craters of all sizes and unusual shapes, a variety of ejecta blankets, large troughs extending around the equatorial region, impact basins, enigmatic dark material, and considerable evidence for mass wasting and surface alteration features (1). Two large impact basins, Veneneia (400km) underlying the larger Rheasilvia basin (500km) dominate the south pole (1,2). Rheasilvia exhibits a huge central peak, with total relief of -22km to 19km, and steep scarps with mass wasting features. Vesta’s global tectonic patterns (two distinct sets of large troughs almost parallel to the equator) strongly correlate with the locations of the two south polar impact basins, and were likely created by their formation (1,3). Numerous unusual asymmetric impact craters and ejecta indicate the strong role of topographic slope in cratering processes on Vesta (1). Such very steep topographic slopes are near to the angle of repose; slope failures make resurfacing due to impacts and their associated gravitational slumping and seismic effects an important geologic process on Vesta (1). Outcrops in crater walls indicate reworked crustal material and impact melt in combination with clusters of pits that show thermal surface processes (4). Relatively dark material of still unknown origin is intermixed in the regolith layers and partially excavated by younger impacts yielding dark outcrops, rays and ejecta (1,5). Finally, Vesta’s surface is younger than expected (6). (1) Jaumann, et al., 2012, Science 336, 687-690; (2) Schenk et al., 2012, Science 336, 964-967; (3) Buczkowski, et al., 2012, GRL, submitted; (4) Denevi, et al., 2012, Science, submitted; (5) McCord, et al., 2012, Nature, submitted; (6) Marchi, et al., 2012, Science 336, 690-694.

Ralf, Jaumann; Russell, C. T.; Raymond, C. A.; Pieters, C. M.; Yingst, R. A.; Williams, D. A.; Buczkowski, D. L.; Schenk, P.; Denevi, B.; Krohn, K.; Stephan, K.; Roatsch, T.; Preusker, F.; Otto, K.; Mest, S. C.; Ammannito, E.; Blewett, D.; Carsenty, U.; DeSanctis, C. M.; Garry, W.; Hiesinger, H.; Keller, H. U.; Kersten, E.; Marchi, S.; Matz, K. D.; McCord, T. B.; McSween, H. Y.; Mottola, S.; Nathues, A.; Neukum, G.; O'Brien, D. P.; Schmedemann, N.; Scully, J. E. C.; Sykes, M. V.; Zuber, M. T.

2012-10-01

310

Geology of Kentucky  

NSDL National Science Digital Library

This website contains geologic maps of Kentucky, with a discussion of geologic time in regards to the rocks, minerals, fossils, and economic deposits found there. There are also sections that describe strata and geologic structures beneath the surface (faults, basins, and arches), the structural processes (folding and faulting) that create stratigraphic units, the geomorphology of the state, geologic information by county, a general description of geologic time, fossil, rocks, and minerals of Kentucky, and a virtual field trip through Natural Bridges State Park. Links are provided for further information.

311

Geological Survey research 1976  

USGS Publications Warehouse

This U.S. Geological Survey activities report includes a summary of recent (1976 fiscal year) scientific and economic results accompanied by a list of geologic and hydrologic investigations in progress and a report on the status of topographic mapping. The summary of results includes: (1) Mineral resources, Water resources, (2) Engineering geology and hydrology, (3) Regional geology, (4) Principles and processes, (5) Laboratory and field methods, (6) Topographic surveys and mapping, (7) Management of resources on public lands, (8) Land information and analysis, and (9) Investigations in other countries. Also included are lists of cooperating agencies and Geological Survey offices. (Woodard-USGS)

Geological Survey (U.S.)

1976-01-01

312

Geological Survey research 1978  

USGS Publications Warehouse

This U.S. Geological Survey activities report includes a summary of 1978 fiscal year scientific and economic results accompanied by a list of geologic and hydrologic investigations in progress and a report on the status of topographic mapping. The summary of results includes: (1) Mineral and water resources, (2) Engineering geology and hydrology, (3) Regional geology, (4) Principles and processes, (5) Laboratory and field methods, (6) Topographic surveys and mapping, (7) Management of resources on public lands, (8) Land information and analysis, and (9) Investigations in other countries. Also included are lists of cooperating agencies and Geological Survey offices. (Woodard-USGS)

1978-01-01

313

Utah Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Utah Geological Survey. Materials available here include news articles and information on geologic hazards; information on places of geological interest; and popular geology topics such as earthquakes, rocks and minerals, fossils, economic resources, groundwater resources, and others. Educational resources include teaching kits, the 'Teacher's Corner' column in the survey's newsletter, and a series of 'Glad You Asked' articles on state geological topics. There is also an extensive list of free K-12 educational materials, as well as a set of curriculum materials such as activity packets, slide shows, and teachers' handbooks, which are available to order.

314

Preliminary Geologic Characterization of West Coast States for Geologic Sequestration  

SciTech Connect

Characterization of geological sinks for sequestration of CO{sub 2} in California, Nevada, Oregon, and Washington was carried out as part of Phase I of the West Coast Regional Carbon Sequestration Partnership (WESTCARB) project. Results show that there are geologic storage opportunities in the region within each of the following major technology areas: saline formations, oil and gas reservoirs, and coal beds. The work focused on sedimentary basins as the initial most-promising targets for geologic sequestration. Geographical Information System (GIS) layers showing sedimentary basins and oil, gas, and coal fields in those basins were developed. The GIS layers were attributed with information on the subsurface, including sediment thickness, presence and depth of porous and permeable sandstones, and, where available, reservoir properties. California offers outstanding sequestration opportunities because of its large capacity and the potential of value-added benefits from enhanced oil recovery (EOR) and enhanced gas recovery (EGR). The estimate for storage capacity of saline formations in the ten largest basins in California ranges from about 150 to about 500 Gt of CO{sub 2}, depending on assumptions about the fraction of the formations used and the fraction of the pore volume filled with separate-phase CO{sub 2}. Potential CO{sub 2}-EOR storage was estimated to be 3.4 Gt, based on a screening of reservoirs using depth, an API gravity cutoff, and cumulative oil produced. The cumulative production from gas reservoirs (screened by depth) suggests a CO{sub 2} storage capacity of 1.7 Gt. In Oregon and Washington, sedimentary basins along the coast also offer sequestration opportunities. Of particular interest is the Puget Trough Basin, which contains up to 1,130 m (3,700 ft) of unconsolidated sediments overlying up to 3,050 m (10,000 ft) of Tertiary sedimentary rocks. The Puget Trough Basin also contains deep coal formations, which are sequestration targets and may have potential for enhanced coal bed methane recovery (ECBM).

Larry Myer

2005-09-29

315

Stochastic models of solute transport in highly heterogeneous geologic media  

SciTech Connect

A stochastic model of anomalous diffusion was developed in which transport occurs by random motion of Brownian particles, described by distribution functions of random displacements with heavy (power-law) tails. One variant of an effective algorithm for random function generation with a power-law asymptotic and arbitrary factor of asymmetry is proposed that is based on the Gnedenko-Levy limit theorem and makes it possible to reproduce all known Levy {alpha}-stable fractal processes. A two-dimensional stochastic random walk algorithm has been developed that approximates anomalous diffusion with streamline-dependent and space-dependent parameters. The motivation for introducing such a type of dispersion model is the observed fact that tracers in natural aquifers spread at different super-Fickian rates in different directions. For this and other important cases, stochastic random walk models are the only known way to solve the so-called multiscaling fractional order diffusion equation with space-dependent parameters. Some comparisons of model results and field experiments are presented.

Semenov, V.N.; Korotkin, I.A.; Pruess, K.; Goloviznin, V.M.; Sorokovikova, O.S.

2009-09-15

316

Hanford Site Guidelines for Preparation and Presentation of Geologic Information  

SciTech Connect

A complex geology lies beneath the Hanford Site of southeastern Washington State. Within this geology is a challenging large-scale environmental cleanup project. Geologic and contaminant transport information generated by several U.S. Department of Energy contractors must be documented in geologic graphics clearly, consistently, and accurately. These graphics must then be disseminated in formats readily acceptable by general graphics and document producing software applications. The guidelines presented in this document are intended to facilitate consistent, defensible, geologic graphics and digital data/graphics sharing among the various Hanford Site agencies and contractors.

Lanigan, David C.; Last, George V.; Bjornstad, Bruce N.; Thorne, Paul D.; Webber, William D.

2010-04-30

317

Kansas Geological Survey  

NSDL National Science Digital Library

The mission of the Kansas Geological Survey, operated by the University of Kansas in connection with its research and service program, is to conduct geological studies and research and to collect, correlate, preserve, and disseminate information leading to a better understanding of the geology of Kansas, with special emphasis on natural resources of economic value, water quality and quantity, and geologic hazards. The website includes information about the High Plains and Ogallala aquifers, the Upper Arkansas corridor, the Dakota aquifer, county and state geologic maps, an online bibliography of Kansas geology, publications, a photo archive, a digital petroleum atlas, a petroleum primer for the state, gravity and magnetic maps, Hugoton project information, and details about the Hutchinson Kansas natural gas fires. The educational resources section contains a mineral information page for the state, and GeoKansas, which provides information on state geology for schools.

318

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

SciTech Connect

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 saline 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.

Deng, Hailin [Los Alamos National Laboratory; Dai, Zhenxue [Los Alamos National Laboratory; Jiao, Zunsheng [Wyoming State Geological Survey; Stauffer, Philip H. [Los Alamos National Laboratory; Surdam, Ronald C. [Wyoming State Geological Survey

2011-01-01

319

Seismic Determination of Reservoir Heterogeneity: Application to the Characterization of Heavy Oil Reservoirs  

SciTech Connect

The objective of the project was to examine how seismic and geologic data could be used to improve characterization of small-scale heterogeneity and their parameterization in reservoir models. The study was performed at West Coalinga Field in California.

Imhof, Matthias G.; Castle, James W.

2003-03-12

320

Geology Fieldnotes: Mojave National Preserve, California  

NSDL National Science Digital Library

Visitors can access information on the geology of the Mojave National Preserve in California. Features include a field trip describing areas of interest at the preserve, as well as a geologic time scale describing the history and development of the area. There are discussions of the formation and history of the present day playa lakes, the underlying Paleozoic limestone and dolomite, and the formation of Mitchell Caverns. Other topics include eolian activity and resulting features in the Kelso Dunes National Natural Landmark and the Devil's Playground, and the role of granitic and metamorphic rock in the formation of pediments. There is also a geologic map of the area and links to maps and technical papers.

321

AN INTEGRATED VIEW OF GROUNDWATER FLOW CHARACTERIZATION AND MODELING IN FRACTURED GEOLOGIC MEDIA  

EPA Science Inventory

The particular attributes of fractured geologic media pertaining to groundwater flow characterization and modeling are presented. These cover the issues of fracture network and hydraulic control of fracture geometry parameters, major and minor fractures, heterogeneity, anisotrop...

322

Modeling geologic storage of carbon dioxide: Comparison ofnon-hysteretic chracteristic curves  

SciTech Connect

TOUGH2 models of geologic storage of carbon dioxide (CO2) in brine-bearing formations use characteristic curves to represent the interactions of non-wetting-phase CO2 and wetting-phase brine. When a problem includes both injection of CO2 (a drainage process) and its subsequent post-injection evolution (a combination of drainage and wetting), hysteretic characteristic curves are required to correctly capture the behavior of the CO2 plume. In the hysteretic formulation, capillary pressure and relative permeability depend not only on the current grid-block saturation, but also on the history of the saturation in the grid block. For a problem that involves only drainage or only wetting, a nonhysteretic formulation, in which capillary pressure and relative permeability depend only on the current value of the grid-block saturation, is adequate. For the hysteretic formulation to be robust computationally, care must be taken to ensure the differentiability of the characteristic curves both within and beyond the turning-point saturations where transitions between branches of the curves occur. Two example problems involving geologic CO2 storage are simulated using non-hysteretic and hysteretic models, to illustrate the applicability and limitations of non-hysteretic methods: the first considers leakage of CO2 from the storage formation to the ground surface, while the second examines the role of heterogeneity within the storage formation.

Doughty, Christine

2006-04-28

323

Heterogeneity of an earth  

NASA Astrophysics Data System (ADS)

The study of magnetic anomaly field structure of the Barents Sea water area along seismic and extended profiles intersecting known fields is carried out. Geomagnetic and density sections down to 40 km depth are constructed. This allowed the estimation of heterogeneities of the Barents Sea water area deep structure. The analysis of geomagnetic and density sections along extended profiles showed the confinedness of oil-and-gas bearing provinces to deep permeable zones characterized by reduced magnetic and density features. Based on the analysis of permeable zones, regional diagnostic features similar to those obtained earlier in oil-and-gas bearing provinces in other regions, for example, in Timan-Pechora, Volga-Urals and Siberian, as well as in the Northern and Norwegian seas water areas, are revealed. The analysis of magnetic and gravity fields over the region area allowed the delineation of weakened zones as intersection areas of weakly magnetic areals with reduced density. Within the Barents Sea water area, permeable areas with lenticular-laminated structure of the upper and lower Earth's crust containing weakly magnetic areals with reduced rock density within the depth range of 8-12 and 15-20 km are revealed. Such ratio of magnetic and density heterogeneities in the Earth's crust is characteristic for zones with proved oil-and-gas content in the European part of the Atlantic Ocean water area. North Kildin field on 1 AR profile is confined to a trough with thick weakly magnetic stratum discontinuously traced to a depth of 6-10 km. At a depth of approximately 15 km, a lens of weakly magnetic and porous formations is observed. Ludlov field in the North Barents trough is confined to a zone of weakly magnetic rocks with reduced density traced to a depth of 8-9 km. Deeper, at ?=15 km, a lenticular areal of weakly magnetic formations with reduced density is observed. The profile transecting the Stockman field shows that it is located in the central part of a permeable zone. Ledovoe field is in the northern margin of the same zone. SPAN calculations of magnetic and gravity fields in areal option allowed obtaining the distribution of permeable weakly magnetic zones in the Barents Sea water area. The most significant ones are confined to Franz-Victoria trough, Severnaya depression, Malygin saddle, Bjarmeland syneclise, Murmansk-Kurentsovo monocline, Southern Lunin trough and depression, Northern Stockman depression, and Southern Barents syneclise.

Litvinova, T.; Petrova, A.

2009-04-01

324

Geologic mapping of Europa  

USGS Publications Warehouse

Galileo data enable the major geological units, structures, and surface features to be identified on Europa. These include five primary units (plains, chaos, band, ridge, and crater materials) and their subunits, along with various tectonic structures such as faults. Plains units are the most widespread. Ridged plains material spans a wide range of geological ages, including the oldest recognizable features on Europa, and appears to represent a style of tectonic resurfacing, rather than cryovolcanism. Smooth plains material typically embays other terrains and units, possibly as a type of fluid emplacement, and is among the youngest material units observed. At global scales, plains are typically mapped as undifferentiated plains material, although in some areas differences can be discerned in the near infrared which might be related to differences in ice grain size. Chaos material is composed of plains and other preexisting materials that have been severely disrupted by inferred internal activity; chaos is characterized by blocks of icy material set in a hummocky matrix. Band material is arrayed in linear, curvilinear, wedge-shaped, or cuspate zones with contrasting albedo and surface textures with respect to the surrounding terrain. Bilateral symmetry observed in some bands and the relationships with the surrounding units suggest that band material forms by the lithosphere fracturing, spreading apart, and infilling with material derived from the subsurface. Ridge material is mapped as a unit on local and some regional maps but shown with symbols at global scales. Ridge material includes single ridges, doublet ridges, and ridge complexes. Ridge materials are considered to represent tectonic processes, possibly accompanied by the extrusion or intrusion of subsurface materials, such as diapirs. The tectonic processes might be related to tidal flexing of the icy lithosphere on diurnal or longer timescales. Crater materials include various interior (smooth central, rough inner, and annular massif) and exterior (continuous ejecta) subunits. Structural features and landforms are shown with conventional symbols. Type localities for the units are identified, along with suggestions for portraying the features on geological maps, including colors and letter abbreviations for material units. Implementing these suggestions by the planetary mapping community would facilitate comparisons of maps for different parts of Europa and contribute to an eventual global synthesis of its complex geology. On the basis of initial mapping results, a stratigraphic sequence is suggested in which ridged plains form the oldest unit on Europa, followed by development of band material and individual ridges. Band materials tend to be somewhat older than ridges, but in many areas the two units formed simultaneously. Similarly, the formation of most chaos follows the development of ridged plains; although chaos is among the youngest materials on Europa, some chaos units might have formed contemporaneously with ridged plains. Smooth plains generally embay all other units and are late-stage in the evolution of the surface. C1 craters are superposed on ridged plains but are crosscut by other materials, including bands and ridges. Most c2 craters postdate all other units, but a few c2 craters are cut by ridge material. C3 craters constitute the youngest recognizable material on Europa. Copyright 2000 by the American Geophysical Union.

Greeley, R.; Figueredo, P. H.; Williams, D. A.; Chuang, F. C.; Klemaszewski, J. E.; Kadel, S. D.; Prockter, L. M.; Pappalardo, R. T.; Head, III, J. W.; Collins, G. C.; Spaun, N. A.; Sullivan, R. J.; Moore, J. M.; Senske, D. A.; Tufts, B. R.; Johnson, T. V.; Belton, M. J. S.; Tanaka, K. L.

2000-01-01

325

Coalition Formation with Uncertain Heterogeneous Information*  

E-print Network

by groups. This is the case in the Request For Proposal (RFP) domain, where some requester business agent issues an RFP - a complex task comprised of sub-tasks - and several service provider agents need to join together to address this RFP. In such environments the value of the RFP may be common knowledge, however

Kraus, Sarit

326

Wave Propagation in Jointed Geologic Media  

SciTech Connect

Predictive modeling capabilities for wave propagation in a jointed geologic media remain a modern day scientific frontier. In part this is due to a lack of comprehensive understanding of the complex physical processes associated with the transient response of geologic material, and in part it is due to numerical challenges that prohibit accurate representation of the heterogeneities that influence the material response. Constitutive models whose properties are determined from laboratory experiments on intact samples have been shown to over-predict the free field environment in large scale field experiments. Current methodologies for deriving in situ properties from laboratory measured properties are based on empirical equations derived for static geomechanical applications involving loads of lower intensity and much longer durations than those encountered in applications of interest involving wave propagation. These methodologies are not validated for dynamic applications, and they do not account for anisotropic behavior stemming from direcitonal effects associated with the orientation of joint sets in realistic geologies. Recent advances in modeling capabilities coupled with modern high performance computing platforms enable physics-based simulations of jointed geologic media with unprecedented details, offering a prospect for significant advances in the state of the art. This report provides a brief overview of these modern computational approaches, discusses their advantages and limitations, and attempts to formulate an integrated framework leading to the development of predictive modeling capabilities for wave propagation in jointed and fractured geologic materials.

Antoun, T

2009-12-17

327

Physical and geological processes of delta formation  

E-print Network

Tss -4 e.4sf t()( gs W28 suF5 M 9s1 28 2 rMuF.0sT 0T2-4ss -4 0gs VsMFg98-r25 HsF2T0us40 M6 0gs D2T0sT L-5 DMuF249, I40sT-4y 0gs n, S, PTu9 28 2 FT-i20s -4 h2Trgf t(Jt hTf R20s8 8sTis1 W-0g 0gs SsrM41 l-s51 PT0-55sT9 Lo8sTi2v 0-M4 R20025-M4 .40-5 e.59f t...(Jbc, lM55MW-4y 0T2-4-4y 28 24 Pi-20-M4 D21s0 Bhs0sMTM5My9^ 20 0gs n4-isT8-09 M6 SM.0gsT4 D25-6MT4-2 BEM8 P4ys5s8^ 241 0gs n4-isT8-09 M6 Dg-r2yMf gs yT21.20s1 W-0g 1-80-4r0-M4 241 W28 rMuu-88-M4s1 28 2 SsrM41 E-s.0s4240 -4 h29f t(J)7 P-T lMTrs 288-y4us...

Bates, Charles Carpenter

2013-10-04

328

Andrei borisovich vistelius: a dominant figure in 20th century mathematical geology  

USGS Publications Warehouse

Andrei Borisovich Vistelius (1915-1995), along with William Christian Krumbein (1902-1979) and John Cedric Griffiths (1912-1992), were dominant figures in the formative and development years of mathematical (or quantitative) geology as a subdiscipline of geology.

Merriam, D.F.

2001-01-01

329

Louisiana Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Louisiana Geological Survey (LGS). The site includes general information about LGS and its various offices, as well as an overview of the Basin Research Energy Section, the oil, gas, and coal research section of LGS. The publications and data page features a catalog and ordering information for documents on mineral resources, fossils, water resources, geological bulletins and maps, and many others, as well as a selection of downloadable maps, including 30 x 60 minute geologic quadrangles, a generalized geologic map of the state with accompanying text, and an online map viewer of the state with selectable layers (geology, water bodies, cultural features, and Landsat imagery). There is also an online listing of well logs, grouped by parish, online listings of core samples, grouped by state, and downloadable public information documents on a variety of geologic topics.

330

Sedimentology and petroleum geology  

SciTech Connect

This book presents an introduction to sedimentology as well as petroleum geology. It integrates both subjects, which are closely related but mostly treated separately. The author covers the basic aspects of sedimentology, sedimentary geochemistry and diagenesis. Principles of stratigraphy, seismic stratigraphy and basin modelling forms the base for the part on petroleum geology. Subjects discussed include the composition of kerogen and hydrocarbons, theories of migration and trapping of hydrocarbons and properties of reservoir rocks. Introductions to well logging and production geology are given.

Bjorlykke, K.O. (Oslo Univ. (Norway))

1989-01-01

331

Dealing with spatial heterogeneity  

NASA Astrophysics Data System (ADS)

Heterogeneity can be dealt with by defining homogeneous equivalent properties, known as averaging, or by trying to describe the spatial variability of the rock properties from geologic observations and local measurements. The techniques available for these descriptions are mostly continuous Geostatistical models, or discontinuous facies models such as the Boolean, Indicator or Gaussian-Threshold models and the Markov chain model. These facies models are better suited to treating issues of rock strata connectivity, e.g. buried high permeability channels or low permeability barriers, which greatly affect flow and, above all, transport in aquifers. Genetic models provide new ways to incorporate more geology into the facies description, an approach that has been well developed in the oil industry, but not enough in hydrogeology. The conclusion is that future work should be focused on improving the facies models, comparing them, and designing new in situ testing procedures (including geophysics) that would help identify the facies geometry and properties. A world-wide catalog of aquifer facies geometry and properties, which could combine site genesis and description with methods used to assess the system, would be of great value for practical applications. On peut aborder le problème de l'hétérogénéité en s'efforçant de définir une perméabilité équivalente homogène, par prise de moyenne, ou au contraire en décrivant la variation dans l'espace des propriétés des roches à partir des observations géologiques et des mesures locales. Les techniques disponibles pour une telle description sont soit continues, comme l'approche Géostatistique, soit discontinues, comme les modèles de faciès, Booléens, ou bien par Indicatrices ou Gaussiennes Seuillées, ou enfin Markoviens. Ces modèles de faciès sont mieux capables de prendre en compte la connectivité des strates géologiques, telles que les chenaux enfouis à forte perméabilité, ou au contraire les faciès fins de barrières de perméabilité, qui ont une influence importante sur les écoulement, et, plus encore, sur le transport. Les modè les génétiques récemment apparus ont la capacité de mieux incorporer dans les modèles de faciès les observations géologiques, chose courante dans l'industrie pétrolière, mais insuffisamment développée en hydrogéologie. On conclut que les travaux de recherche ultérieurs devraient s'attacher à développer les modèles de faciès, à les comparer entre eux, et à mettre au point de nouvelles méthodes d'essais in situ, comprenant les méthodes géophysiques, capables de reconnaître la géométrie et les propriétés des faciès. La constitution d'un catalogue mondial de la géométrie et des propriétés des faciès aquifères, ainsi que des méthodes de reconnaissance utilisées pour arriver à la détermination de ces systèmes, serait d'une grande importance pratique pour les applications. La heterogeneidad se puede manejar por medio de la definición de características homogéneas equivalentes, conocidas como promediar o tratando de describir la variabilidad espacial de las características de las rocas a partir de observaciones geológicas y medidas locales. Las técnicas disponibles para estas descripciones son generalmente modelos geoestadísticos continuos o modelos de facies discontinuos como los modelos Boolean, de Indicador o de umbral de Gaussian y el modelo de cadena de Markow. Estos modelos de facies son mas adecuados para tratar la conectvidad de estratos geológicos (por ejemplo canales de alta permeabilidad enterrados o barreras de baja permeabilidad que tienen efectos importantes sobre el flujo y especialmente sobre el transporte en los acuíferos. Los modelos genéticos ofrecen nuevas formas de incorporar más geología en las descripciones de facies, un enfoque que está bien desarollado en la industria petrolera, pero insuficientemente en la hidrogeología. Se concluye que los trabajos futuros deberían estar más enfocados en mejorar los modelos de facies, en establecer comparaciones y en

Marsily, Gh.; Delay, F.; Gonçalvès, J.; Renard, Ph.; Teles, V.; Violette, S.

2005-03-01

332

Structural Geology 'Research' Conference  

NSDL National Science Digital Library

In this assignment students read and discuss a peer-reviewed journal article and prepare for and attend our class 'research' conference. In the conference they present on an area of current research as discussed in the journal article they read, and they practice formulating questions about other's research. Outcomes: 1. Read and discuss a structural geology peer-reviewed journal article. 2. Prepare a presentation that demonstrates your understanding of a current research topic in structural geology. 3. View and understand several diverse areas within geology and geophysics that use structural geology in research. 4. Ask questions relevant to a research presentation.

Willis, Julie

333

Geological Survey research 1981  

USGS Publications Warehouse

This U.S. Geological Survey activities report includes a summary of 1981 fiscal year scientific and economic results accompanied by a list of geologic, hydrologic, and cartographic investigations in progress. The summary of results includes: (1) Mineral, (2) Water resources, (3) Engineering geology and hydrology, (4) Regional geology, (5) Principles and processes, (6) Laboratory and field methods, (7) Topographic surveys and mapping, (8) Management of resources on public lands, (9) Land information and analysis, and (10) Investigations in other countries. Also included are lists of investigations in progress. (USGS)

1982-01-01

334

Arizona Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Arizona Geological Survey. Information accessible here includes maps, information on oil, gas, and minerals in the state, back issues of the survey's newsletter, and a list of resources for public education in the state. These resources include information centers for Arizona geology and Earth Science, the survey's geology library and bibliographic database, a repository of rock cuttings and cores, and a contact for earth science education who will assist teacher groups in introducing local geology to their classes.

335

Geological myths and reality  

NASA Astrophysics Data System (ADS)

Myths are the result of man's attempts to explain noteworthy features of his environment stemming from unfounded imagination. It is unbelievable that in 21st century the explanation of evident lithospheric plates movements and origin of forces causing this movement is still bound to myths, They are the myth about mantle convection, myth about Earth's expansion, myth about mantle heterogeneities causing the movement of plates and myth about mantle plumes. From 1971 to 1978 I performed extensive study (Ost?ihanský 1980) about the terrestrial heat flow and radioactive heat production of batholiths in the Bohemian Massive (Czech Republic). The result, gained by extrapolation of the heat flow and heat production relationship, revealed the very low heat flow from the mantle 17.7mW m-2 close to the site of the Quarterly volcano active only 115,000 - 15,000 years ago and its last outbreak happened during Holocene that is less than 10,000 years ago. This volcano Komorní H?rka (Kammerbühls) was known by J. W. Goethe investigation and the digging of 300 m long gallery in the first half of XIX century to reach the basaltic plug and to confirm the Stromboli type volcano. In this way the 19th century myth of neptunists that basalt was a sedimentary deposit was disproved in spite that famous poet and scientist J.W.Goethe inclined to neptunists. For me the result of very low heat flow and the vicinity of almost recent volcanoes in the Bohemian Massive meant that I refused the hypothesis of mantle convection and I focused my investigation to external forces of tides and solar heat, which evoke volcanic effects, earthquakes and the plate movement. To disclose reality it is necessary to present calculation of acting forces using correct mechanism of their action taking into account tectonic characteristics of geologic unites as the wrench tectonics and the tectonic of planets and satellites of the solar system, realizing an exceptional behavior of the Earth as quickly rotating body exposed to strong tidal action of Moon and Sun. Ostrihansky, L.: The structure of the earth's crust and the heat-flow--heat-generation relationship in the Bohemian Massif. Tectonophysics, 68(3-4), 325-337, doi:10.1016/0040-1951(80)90182-1 1980.

Ostrihansky, Lubor

2014-05-01

336

Numerical assessment of 3-D macrodispersion in heterogeneous porous media  

E-print Network

. [1] Hydrodynamic dispersion is a key controlling factor of solute transport in heterogeneous porous.20206. 1. Introduction [2] Hydrodynamic dispersion is a major component of solute transport in geological media controlling the relative solute distribution [Bear, 1973; Saffman, 1959] as well

Paris-Sud XI, Université de

337

Factors controlling radionuclide transport behavior in a generic geological radioactive waste repository  

NASA Astrophysics Data System (ADS)

One of the main challenges in designing a geological repository for high-level nuclear waste is the assessment of postclosure safety, which involves the long-term ability of the engineered system and the geological host formation to contain and delay the leakage of radionuclides toward the biosphere. A correct assessment requires detailed knowledge of the factors controlling radionuclide transport in the different components of the geological disposal system. For instance, molecular diffusion, which is considered the dominant transport mechanism in low-permeable geological formations, may be influenced by the heterogeneity of the diffusive parameters and by electrochemical processes. Likewise, the prevalence of advective transport in the near-field excavation damaged zone (EDZ) may be controlled by the hydrogeological conditions in the host formation, as well as by hydrogeological and geometrical properties. In this study, we performed two-dimensional numerical simulations of groundwater flow and radionuclide transport to study the influence of several factors on the prevailing transport mechanism (i.e., advection or molecular diffusion) in the different components of a geological nuclear waste repository system. Particular attention was given to the excavation damaged zone (EDZ) around the repository tunnels and access shaft, which was modeled as a single effective continuum as well as with the dual-porosity approach. We considered different hydrogeological and geometrical factors, including the ambient hydraulic gradient, the presence of groundwater pressure anomalies, and the thickness of the EDZ and its hydraulic properties. By comparing simulation results, we show that transport behavior and the role of the EDZ as a preferential flow path for radionuclide transport is most sensitive to the hydrogeological conditions in the host rock. When the hydraulic gradient in the host rock is reduced by a factor of 5 from the unit value, we observe a significant reduction in the area within the EDZ where advection dominates. However, the presence of overpressures in the host rock, as typically observed in clay-rock formations in sedimentary basins, can significantly increase the importance of advection and consequentially transport velocity, even in systems with a low regional hydraulic gradient. The opposite behavior was observed for an undepressurized system. Transport behavior is also sensitive to the modeling approach used to simulate flow in the EDZ fractures, and to geometrical and hydrogeological parameters of the EDZ.

Bianchi, M.; Liu, H.; Birkholzer, J. T.

2013-12-01

338

SPECIAL TOPIC The influence of geological, geochemical, and biogenic  

E-print Network

SPECIAL TOPIC The influence of geological, geochemical, and biogenic habitat heterogeneity on seep linked to methane, oil and gas seeps have been identified (Sibuet & Olu 1998; Pinheiro et al. 2003 in fluid flow, geochemistry, and substrate type, which give rise to different sets of microbial communities

Levin, Lisa

339

Geology Fieldnotes: White Sands National Monument, New Mexico  

NSDL National Science Digital Library

The White Sands National Monument site contains park geology information, maps, related links, and visitor information. The park geology section discusses the park's geologic history, the formation of the gypsum sand dunes, and the four types of dunes found at the White Sands National Monument: dome, barchan, transverse, and parabolic. The park maps section includes a map of the White Sands National Monument and the surrounding area, showing the location of each type of dune.

340

Geology of Earth's Moon  

NSDL National Science Digital Library

First, researchers at the University of California, San Diego discuss the importance of studying earthquakes on the moon, also known as moonquakes, and the Apollo Lunar Seismic Experiment (1). Users can discover the problems scientists must deal with when collecting the moon's seismic data. The students at Case Western Reserve University created the second website to address three missions the Institute of Space and Astronautical Science (ISAS) has planned between now and 2010, including a mission to the moon (2). Visitors can learn about the Lunar-A probe that will be used to photograph the surface of the moon, "monitor moonquakes, measure temperature, and study the internal structure." Next, the Planetary Data Service (PDS) at the USGS offers users four datasets that they can use to create an image of a chosen area of the moon (3). Each dataset can be viewed as a basic clickable map; a clickable map where users can specify size, resolution, and projection; or an advanced version where visitors can select areas by center latitude and longitude. The fourth site, produced by Robert Wickman at the University of North Dakota, presents a map of the volcanoes on the moon and compares their characteristics with those on earth (4). Students can learn how the gravitational forces on the Moon affect the lava flows. Next, Professor Jeff Ryan at the University of South Florida at Tampa supplies fantastic images and descriptive text of the lunar rocks obtained by the Apollo missions (5). Visitors can find links to images of meteorites, terrestrial rocks, and Apollo landings as well. At the Science Channel website, students and educators can find a video clip discussing the geologic studies on the moon along with videos about planets (6). Users can learn about how studying moon rocks help scientists better understand the formation of the earth. Next, the Smithsonian National Air and Space Museum presents its research of "lunar topography, cratering and impacts basins, tectonics, lava flows, and regolith properties" (7). Visitors can find summaries of the characteristics of the moon and the main findings since the 1950s. Lastly, the USGS Astrogeology Research Program provides archived lunar images and data collected between 1965 and 1992 by Apollo, Lunar Orbiter, Galileo, and Zond 8 missions (8). While the data is a little old, students and educators can still find valuable materials about the moon's topography, chemical composition, and geology.

341

Phenotypically heterogeneous populations in spatially heterogeneous environments  

NASA Astrophysics Data System (ADS)

The spatial expansion of a population in a nonuniform environment may benefit from phenotypic heterogeneity with interconverting subpopulations using different survival strategies. We analyze the crossing of an antibiotic-containing environment by a bacterial population consisting of rapidly growing normal cells and slow-growing, but antibiotic-tolerant persister cells. The dynamics of crossing is characterized by mean first arrival times and is found to be surprisingly complex. It displays three distinct regimes with different scaling behavior that can be understood based on an analytical approximation. Our results suggest that a phenotypically heterogeneous population has a fitness advantage in nonuniform environments and can spread more rapidly than a homogeneous population.

Patra, Pintu; Klumpp, Stefan

2014-03-01

342

Small scale laboratory design investigation of leakage of gaseous CO2 through heterogeneous subsurface system  

NASA Astrophysics Data System (ADS)

The technology for geological sequestration of carbon dioxide has been developed to reduce the CO2 emissions into the atmosphere from the use of fossil fuels in power generation and other industries. One of the main concerns associated with the geological storage is the possible leakage of CO2 into the shallow aquifers, for which effective detection methods are needed. The processes related to the spreading and trapping of CO2 in the reservoir formation and in supercritical conditions have received major attention and form the basis of understanding of CO2 trapping processes. Some of the CO2 may, however, also leak to the upper layers of the rock and all the way to land surface through faults and imperfections in the seal. A proper understanding and capability to detect such leaks is essential for a safe performance of any storage operation. This, in turn, involves a proper understanding of the processes related to the transport of gaseous CO2 in the near-surface conditions, a topic that has received considerably less attention. The objective of this study is to analyze the transport and migration of gaseous CO2 in heterogeneous porous media, in controlled laboratory conditions. CO2 may reach the unsaturated zone by different leak mechanisms which may subsequently affect how and where it can be detected by leakage monitoring program. These mechanisms include exsolution from CO2 supersaturated water and continuous bubbling or gas flow along a leakage path. Below the water table, gaseous CO2 can also be trapped under capillary barriers. However, as more CO2 is supplied by leakage from below the water table, the pressure may at some point exceed the entry pressure of the barrier leading to a leak event. Similarly, fluctuations in the water table may also produce leak events of temporarily trapped CO2. In the unsaturated zone, the CO2 is heavier than air and may accumulate below ground surface and move laterally. The presence of heterogeneity influences both the movement and detectability of the CO2. Our laboratory experiment is designed and implemented for measuring CO2 distribution in time and space through the heterogeneous porous material. The CO2 concentrations through the domain are measured by using sensitive gas sensors. To better understand the consequences of CO2 leakage and how it can be detected, this study presents a conceptual model together with the design and setup of an experimental system to understand the transport, trapping and detectability of gaseous CO2 in a heterogeneous shallow geological system.

Basirat, F.; Sharma, P.; Niemi, A.; Fagerlund, F.

2012-04-01

343

Cellulose conversion under heterogeneous catalysis.  

PubMed

In view of current problems such as global warming, high oil prices, food crisis, stricter environmental laws, and other geopolitical scenarios surrounding the use of fossil feedstocks and edible resources, the efficient conversion of cellulose, a non-food biomass, into energy, fuels, and chemicals has received much attention. The application of heterogeneous catalysis could allow researchers to develop environmentally benign processes that lead to selective formation of value-added products from cellulose under relatively mild conditions. This Minireview gives insight into the importance of biomass utilization, the current status of cellulose conversion, and further transformation of the primary products obtained. PMID:19021143

Dhepe, Paresh L; Fukuoka, Atsushi

2008-01-01

344

Integrated analysis of production potential and profitability of a horizontal well in the Lower Glen Rose Formation, Maverick County, Texas  

SciTech Connect

The U.S. Department of Energy/Morgantown Energy Technology Center (DOE/METC) awarded a contract in 1991 to Prime Energy Corporation (PEC) to demonstrate the benefit of using horizontal wells to recover gas from low permeability formations. The project area was located in the Chittim field of Maverick County, Texas. The Lower Glen Rose Formation in the Chittim field was a promising horizontal well candidate based on the heterogenous nature of the reservoir (suggested by large well-to-well variances in reserves) and the low percentage of economical vertical wells. Since there was substantial evidence of reservoir heterogeneity, it was unknown whether the selected, wellsite would penetrate a reservoir with the desired properties for a horizontal well. Thus, an integrated team was formed to combine geologic analysis, seismic interpretation, reservoir engineering, reservoir simulation, and economic assessment to analyze the production potential and profitability of completing a horizontal well in the Lower Glen Rose formation.

Ammer, J.R.; Mroz, T.H.; Zammerilli, A.M.; Yost, A.B. II [Dept. of Energy, Morgantown, WV (United States); Muncey, J.G.; Hegeman, P.S.

1995-03-01

345

Overview: Gas hydrate geology and geography  

SciTech Connect

Several geological factors which are directly responsible for the presence or absence of gas hydrates have been reviewed and are: tectonic position of the region; sedimentary environments; structural deformation; shale diapirism; hydrocarbon generation and migration; thermal regime in the hydrate formation zone (HFZ); pressure conditions; and hydrocarbon gas supply to the HFZ. Work on gas hydrate formation in the geological environment has made significant advances, but there is still much to be learned. Work is continuing in the deeper offshore areas through the Ocean Drilling Program, Government Agencies, and Industry. The pressure/temperature conditions necessary for formation has been identified for various compositions of natural gas through laboratory investigations and conditions for formation are being advanced through drilling in areas where gas hydrates exist.

Malone, R.D.

1993-06-01

346

Overview: Gas hydrate geology and geography  

SciTech Connect

Several geological factors which are directly responsible for the presence or absence of gas hydrates have been reviewed and are: tectonic position of the region; sedimentary environments; structural deformation; shale diapirism; hydrocarbon generation and migration; thermal regime in the hydrate formation zone (HFZ); pressure conditions; and hydrocarbon gas supply to the HFZ. Work on gas hydrate formation in the geological environment has made significant advances, but there is still much to be learned. Work is continuing in the deeper offshore areas through the Ocean Drilling Program, Government Agencies, and Industry. The pressure/temperature conditions necessary for formation has been identified for various compositions of natural gas through laboratory investigations and conditions for formation are being advanced through drilling in areas where gas hydrates exist.

Malone, R.D.

1993-01-01

347

Layer Cake Geology  

NSDL National Science Digital Library

This classroom activity uses a cake to demonstrate geologic processes and introduce geologic terms. Students will learn how folds and faults occur, recognize the difference in behavior between brittle and ductile rocks, and attempt to predict structures likely to result from application of various forces to layered rocks. They will also attempt to interpret 'core samples' to determine subsurface rock structure.

Wagner, John

348

Earthquakes and Geology  

NSDL National Science Digital Library

In this activity, students investigate the relationship between intensity of ground motion and type of rock or alluvium, as seen in the 1994 Northridge, California earthquake. They will examine a map of Mercalli intensity, a cross-section showing geologic structures and rock types, and a map of surficial geology, and answer questions pertaining to amplification of ground motion and S-wave velocities.

Ozsvath, David

349

Earth Sciences Geology Option  

E-print Network

courses, core Earth Sciences courses, and focused coursework in the option. A graduation checklistEarth Sciences with Geology Option Geological sciences focus on understanding the Earth, from its composition and internal structure to its history and the processes that shape its surface. Our planet

Kurapov, Alexander

350

Structural Geology Techniques  

NSDL National Science Digital Library

The University of Wisconsin - Green Bay has created this collection of material and instructions on how to analyze and plot structural geology data. Topics covered includes planes, lines, relations between lines and planes, geologic structures, intersection of structures with topography, stereonet techniques, stress and strain, and analysis of complex structures.

Dutch, Steven

2009-05-21

351

Geologic mapping of Europa  

Microsoft Academic Search

Galileo data enable the major geological units, structures, and surface features to be identified on Europa. These include five primary units (plains, chaos, band, ridge, and crater materials) and their subunits, along with various tectonic structures such as faults. Plains units are the most widespread. Ridged plains material spans a wide range of geological ages, including the oldest recognizable features

Ronald Greeley; Patricio H. Figueredo; David A. Williams; Frank C. Chuang; James E. Klemaszewski; Steven D. Kadel; Louise M. Prockter; Robert T. Pappalardo; James W. Head; Geoffrey C. Collins; Nicole A. Spaun; Robert J. Sullivan; Jeffrey M. Moore; David A. Senske; B. Randall Tufts; Torrence V. Johnson; Michael J. S. Belton; Kenneth L. Tanaka

2000-01-01

352

Geology in America  

Microsoft Academic Search

I AM somewhat chagrined to find that I appear to you (vol. xi. p. 381) to say that the Geological Survey of Great Britain is especially to blame for the diminution of interest in geology in the country that has done the most for its advancement. My remarks were taken down by a reporter, and I have not seen them

N. S. Shaler

1875-01-01

353

Geology of the Caribbean.  

ERIC Educational Resources Information Center

Describes some of the geologic characteristics of the Caribbean region. Discusses the use of some new techniques, including broad-range swath imaging of the sea floor that produces photograph-like images, and satellite measurement of crustal movements, which may help to explain the complex geology of the region. (TW)

Dillon, William P.; And Others

1988-01-01

354

Radiometric Dating in Geology.  

ERIC Educational Resources Information Center

Described are several aspects and methods of quantitatively measuring geologic time using a constant-rate natural process of radioactive decay. Topics include half lives and decay constants, radiogenic growth, potassium-argon dating, rubidium-strontium dating, and the role of geochronology in support of geological exploration. (DS)

Pankhurst, R. J.

1980-01-01

355

Forensic geology exhumed  

Microsoft Academic Search

Forensic geology binds applied geology to the world of legal controversy and action. However, the term ``forensic'' is often misconstrued. Although even some attorneys apply it only to the marshalling of evidence in criminal cases, it has a much broader definition. One dictionary defines it as ``pertaining to, connected with, or used in courts of law or public discussion and

Joseph Didier Martinez

1991-01-01

356

Geological data bases combine  

Microsoft Academic Search

In a move designed to eliminate overlap and increase coverage of scholarly publications, three major institutions have agreed to pool their resources in compiling a common geological bibliographic data base. The American Geological Institute (AGI), the Bureau de Recherches Geologiques et Minieres (BRGM), and the Centre National de la Recherche Scientifique (CNRS) will begin producing a joint bibliographic record in

Lee Greathouse

1980-01-01

357

Glossary of geology  

SciTech Connect

This third edition of the Glossary of Geology contains approximately 37,000 terms, or 1,000 more than the second edition. New entries are especially numerous in the fields of carbonate sedimentology, hydrogeology, marine geology, mineralogy, ore deposits, plate tectonics, snow and ice, and stratigraphic nomenclature. Many of the definitions provide background information.

Bates, R.L.; Jackson, J.A.

1987-01-01

358

External Resource: Geologic Time  

NSDL National Science Digital Library

This NASA sponsored webpage, Center for Educational Technologies, teaches students about Geologic Time. The age of Earth is so long compared to all periods of time that we humans are familiar with, it has been given a special name: Geologic time. The age

1900-01-01

359

Geologic time scale bookmark  

USGS Publications Warehouse

This bookmark, designed for use with U.S. Geological Survey activities at the 2nd USA Science and Engineering Festival (April 26–29, 2012), is adapted from the more detailed Fact Sheet 2010–3059 "Divisions of Geologic Time." The information that it presents is widely sought by educators and students.

U.S. Geological Survey

2012-01-01

360

People and Geology.  

ERIC Educational Resources Information Center

Provides background information on the many natural resources we extract from the earth's crust, including metals, graphite, and other minerals, as well as fossil fuels. Contains teaching activities such as a geologic scavenger hunt, a geology chronology, and the recycling of aluminum. Includes a reproducible handout for the activity on aluminum.…

Naturescope, 1987

1987-01-01

361

Geologic mapping of tectonic planets  

Microsoft Academic Search

Geological analysis of planets typically begins with the construction of a geologic map of the planets’ surfaces using remote data sets. Geologic maps provide the basis for interpretations of geologic histories, which in turn provide critical relations for understanding the range of processes that contributed to the evolution. Because geologic mapping should ultimately lead to the discovery of the types

Vicki L. Hansen

2000-01-01

362

Fight or flight: plastic behavior under self-generated heterogeneity  

Microsoft Academic Search

Plants are able to plastically respond to their ubiquitously heterogeneous environments; however, little is known about the\\u000a conditions under which plants are expected to avoid or confront their neighbors in dense stands, where heterogeneity is self-generated\\u000a by non-uniform growth and feedback between plant interactions and stand heterogeneity. We studied the role of plasticity for\\u000a spatial pattern-formation and the resulting stand-level

Tomáš Herben; Ariel Novoplansky

2010-01-01

363

Fossil formation  

NSDL National Science Digital Library

The National Science Education Standards Life Science Content Standard mentions that fossils indicate extinct species and contribute to an understanding of evolution and diversity. The Earth and Space Sciences Content Standard tells us they provide clues about past environments. But what is a fossil? How does it form? The processes can be complex. An understanding of fossil formation will enable accurate student conceptions of related science concepts including methods of science in geology, paleontology, and evolution.

University, Staff A.

2008-03-07

364

Field Geology/Processes  

NASA Technical Reports Server (NTRS)

The field geology/process group examined the basic operations of a terrestrial field geologist and the manner in which these operations could be transferred to a planetary lander. Four basic requirements for robotic field geology were determined: geologic content; surface vision; mobility; and manipulation. Geologic content requires a combination of orbital and descent imaging. Surface vision requirements include range, resolution, stereo, and multispectral imaging. The minimum mobility for useful field geology depends on the scale of orbital imagery. Manipulation requirements include exposing unweathered surfaces, screening samples, and bringing samples in contact with analytical instruments. To support these requirements, several advanced capabilities for future development are recommended. Capabilities include near-infrared reflectance spectroscopy, hyper-spectral imaging, multispectral microscopy, artificial intelligence in support of imaging, x ray diffraction, x ray fluorescence, and rock chipping.

Allen, Carlton; Jakes, Petr; Jaumann, Ralf; Marshall, John; Moses, Stewart; Ryder, Graham; Saunders, Stephen; Singer, Robert

1996-01-01

365

Wyoming State Geological Survey  

NSDL National Science Digital Library

This agency's mission is to study, examine, and seek an understanding of the geology, mineral resources, and physical features of the State; to prepare, publish, and distribute reports and maps of Wyoming's geology, mineral resources, and physical features; and to provide information, advice, and services related to the geology, mineral resources, and physical features of the State. This site contains details and reports about metals in Wyoming, earthquakes and other hazards, coal, industrial minerals, uranium, oil and gas. The field trip section contains details about various areas to visit with students and gives a general geologic description. There is also a searchable bibliography with publications about Wyoming geology. Links are provided for additional resources.

366

Generalized Geologic Map of the Conterminous United States  

NSDL National Science Digital Library

This site from the USGS features a geologic map of the United States using data prepared for publication in the National Atlas of the United States. There are explanations, documentations, and PDF files presenting the geologic map and a map unit chart, plus archives of ArcInfo files in several formats.

Usgs

367

SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 SEQUESTRATION (PRESENTATION)  

EPA Science Inventory

The paper discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of the...

368

SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 SEQUESTRATION  

EPA Science Inventory

The chapter discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of t...

369

SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 STORAGE  

EPA Science Inventory

The paper discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of the...

370

4th Grade Geology Lesson Plans  

NSDL National Science Digital Library

This site has a lesson plan for a class activity on mountain building and graben and horst formation. This particular lesson is number 14, at the top of the page. There are a few other geology lesson plans also listed on this site.

371

Geology Fieldnotes: Buffalo National River, Arkansas  

NSDL National Science Digital Library

This site contains information on the Buffalo National River in Arkansas, including geology, park maps, and visitor information. It discusses landscape formations, the course of the river, and prehistoric sites along the river, which is situated in the Ozarks of Arkansas.

372

Life on Guam: Geology. 1977 Edition.  

ERIC Educational Resources Information Center

As part of an updated series of activity oriented educational materials dealing with aspects of the Guam environment, this publication focuses on the physical environment of Guam through an introduction to the geology of Guam. Contents include the formation of Guam, weathering and erosion, earthquakes, soil, and water. Activities investigate…

Elkins, Gail; And Others

373

GEOLOGICAL NOTE Desert Pavement: An Environmental Canary?  

E-print Network

GEOLOGICAL NOTE Desert Pavement: An Environmental Canary? P K. Haft Division of Earth and Ocean 27708 Ie-mail: /wff@geo.duke_eciul ABSTRACT Ongoing ctisruption of ancient, varnished desert pavement that the pavement disturbances reported here ~ue rarc on the millcnnhll time scale of desert varnish format ion

Ahmad, Sajjad

374

Geology Fieldnotes: Arches National Park, Utah  

NSDL National Science Digital Library

This park is located on the Colorado Plateau near Moab, Utah, and contains many arches and sculpted sedimentary rocks. The visible rock formations in the park are the Entrada and Navajo sandstones. Covered topics include the formation of arches in stages, different types of arches, as well as sizes and names (Delicate Arch being the most famous). The site also provides visitor information, photos, maps, additional links, and a teacher feature (tools for teaching geology with National Park examples).

Foos, Annabelle

375

HETEROGENEOUS INTEGRATION OF BIOMIMETIC ACOUSTIC MICROSYSTEMS  

E-print Network

HETEROGENEOUS INTEGRATION OF BIOMIMETIC ACOUSTIC MICROSYSTEMS Andreas G. Andreou, David H. Goldberg patterns. Note that our aim is not the This work was supported by DARPA/ONR MURI N00014 to maximize the amount of reliable in- formation for identiÃ?cation,classiÃ?cation and recognition tasks

Cauwenberghs, Gert

376

Virtual Tour of Maine Geology  

NSDL National Science Digital Library

This selection of slide shows provides a photographic tour of Maine geology. Users can choose slide shows on surficial, bedrock, and coastal geology; fossils, geologic hazards, groundwater and wells; or mineral collecting, mining, and quarrying.

377

Using Schema Matching to Simplify Heterogeneous Data Translation  

Microsoft Academic Search

A broad spectrum of data is available on the Web in distinct heterogeneous sources, and stored under different formats. As the num- ber of systems that utilize this heterogeneous data grows, the importance of data translation and conversion mechanisms increases greatly. In this paper we present a new translation system, based on schema-matching, aimed at simplifying the intricate task of

Tova Milo; Sagit Zohar

1998-01-01

378

Effective Dispersion in Temporally Fluctuating Flow in Heterogeneous Media  

Microsoft Academic Search

We report on the effective dispersion of a solute in the temporally fluctuating random flow through a heterogeneous medium. Flow in natural formations is subject to temporal fluctuations on a range of time scales, including hyperannual climatic fluctuations, seasonal and irrigation cycles, daily barometric variations and earth tides. The interaction of spatial heterogeneity with temporal fluctuations and local dispersion enhances

J. Carrera; M. Dentz; V. Zavala

2005-01-01

379

Modeling Fractures in Thermal Systems: Thermal-Mechanical Feedback and Vein Formation  

NSDL National Science Digital Library

Barb Dutrow, Department of Geology & Geophysics, Louisiana State University Topic: Mineralogy, Petrology, fracture formation Course type: Upper level undergraduate course Description In many geologic systems, ...

380

Report on geologic exploration activities  

SciTech Connect

This report provides an overview of the geological exploration activities being carried out as part of the National Waste Terminal Storage (NWTS) Program, which has been established by the US Department of Energy (DOE) to develop the technology and provide the facilities for the safe, environmentally acceptable isolation of civilian high-level and transuranic nuclear wastes, including spent fuel elements, for which the Federal government is reponsible. The principal programmatic emphasis is on disposal in mined geologic repositories. Explorations are being conducted or planned in various parts of the country to identify potential sites for such repositories. The work is being undertaken by three separate but coordinated NWTS project elements. Under the Basalt Waste Isolation Project (BWIP), basalt formations underlying DOE's Hanford Reservation are being investigated. Granite, tuff, and shale formations at the DOE Nevada Test Site (NTS) are being similarly studied in the Nevada Nuclear Waste Storage Investigations (NNWSI). The Office of Nuclear Waste Isolation (ONWI) is investigating domed salt formations in several Gulf Coast states and bedded salt formations in Utah and Texas. Th ONWI siting studies are being expanded to include areas overlying crystalline rocks, shales, and other geohydrologic systems. The current status of these NWTS efforts, including the projected budgets for FY 1981, is summarized, and the criteria and methodology being employed in the explorations are described. The consistency of the overall effort with the recommendations presented in the Report to the President by the Interagency Review Group on Nuclear Waste Management (IRG), as well as with documents representing the national technical consensus, is discussed.

None

1980-01-01

381

Report on geologic exploration activities  

SciTech Connect

This report provides an overview of the geological exploration activities being carried out as part of the National Waste Terminal Storage (NWTS) Program, which has been established by the US Department of Energy (DOE) to develop the technology and provide the facilities for the safe, environmentally acceptable isolation of civilian high-level and transuranic nuclear wastes, including spent fuel elements, for which the Federal government is responsible. The principal programmatic emphasis is on disposal in mined geologic repositories. Explorations are being conducted or planned in various parts of the country to identify potential sites for such repositories. The work is being undertaken by three separate but coordinated NWTS project elements. Under the Basalt Waste Isolation Project (BWIP), basalt formations underlying DOE's Hanford Reservation are being investigated. Granite, tuff, and shale formations at the DOE Nevada Test Site (NTS) are being similarly studied in the Nevada Nuclear Waste Storage Investigations (NNWSI). The Office of Nuclear Waste Isolation (ONWI) is investigating domed salt formations in several Gulf Coast states and bedded salt formations in Utah and Texas. The ONWI siting studies are being expanded to include areas overlying crystalline rocks, shales, and other geohydrologic systems. The current status of these NWTS efforts, including the projected budgets for FY 1981, is summarized, and the criteria and methodology being employed in the explorations are described. The consistency of the overall effort with the recommendations presented in the Report to the President by the Interagency Review Group on Nuclear Waste Management (IRG), as well as with documents representing the national technical consensus, is discussed.

Breslin, J.; Laughon, R. B.; Hall, R. J.; Voss, J. W. [comps.

1980-01-01

382

Journal of Geology  

NSDL National Science Digital Library

From the University of Chicago Press's Journals Division, the Journal of Geology is currently available online free of charge (note: subscription fees may soon apply, but no initiation date is provided). This first-rate technical journal, which publishes "research and theory in geophysics, geochemistry, sedimentology, geomorphology, petrology, plate tectonics, volcanology, structural geology, mineralogy, and planetary sciences" has been in print form since 1893. All of the 1999 issues of the Journal of Geology electronic edition are available here. Internet users can access full-text articles with internal links to references and figures (html, .pdf. .ps).

383

Indiana Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Indiana Geological Survey (IGS). Site materials include information on Earth science issues such as groundwater, mapping, coal and mineral resources, oil and gas, and seismic hazards. There is also information on the geologic time scale and stratigraphic record, rocks and minerals, fossils (including nautiloids of the Ordovician period in Indiana), caves and karst topography in Indiana, and glacial geology. The Geographic Information Ssytems (GIS) and mapping section includes a GIS atlas for the state, an online map viewer, links to the Indiana coal mine information system, petroleum database management system, and a download page where users can access GIS datasets for the state.

384

Geology of caves  

USGS Publications Warehouse

A cave is a natural opening in the ground extending beyond the zone of light and large enough to permit the entry of man. Occurring in a wide variety of rock types and caused by widely differing geological processes, caves range in size from single small rooms to intercorinecting passages many miles long. The scientific study of caves is called speleology (from the Greek words spelaion for cave and logos for study). It is a composite science based on geology, hydrology, biology, and archaeology, and thus holds special interest for earth scientists of the U.S. Geological Survey.

Morgan, I. M., Davies, W. E.

1991-01-01

385

What is Geologic Time?  

NSDL National Science Digital Library

This webpage of the National Park Service (NPS) and United States Geological Survey (USGS) discusses geologic time and what it represents. Beginning about 4.6 billion years ago and ending in the present day, this site exhibits (to scale) the various eras, periods, eons, and epochs of Earth's history with a downloadable geologic time scale available. Links provide maps of what the Earth looked like at various times in its history, as well as a description of how scientists developed the time scale and how they know the age of the Earth.

386

Urgent problems of geological substantiation of geomechanical calculations  

SciTech Connect

This article reviews current problems in the approach to and analysis of geomechanical data for hydroelectric power plant and dam siting studies. These problems include the classification of rock masses from an engineering geology standpoint, the approach to geological modeling and microregionalization of formations and structures, data acquisition inconsistencies in geophysical survey methods, and the estimation of the internal stress states of rock formations. Recommendations are outlined in each of these problem fields.

Varga, A.A.

1987-08-01

387

Radionuclide migration in clayrock host formations for deep geological disposal of radioactive waste: advances in process understanding and up-scaling methods resulting from the EC integrated project `Funmig  

NASA Astrophysics Data System (ADS)

One of the ‘pillars' supporting Safety Cases for deep geological disposal of radioactive waste in clayrock formations is the knowledge base regarding radionuclide (Rn) retention by sorption and diffusion-driven transport which is why the EC integrated project ‘Funmig' focused a major part of its effort on advancing understanding of these two macroscopic phenomena. This talk presents some of the main results of this four year effort (2005-2008). One of the keys to understanding diffusion-driven transport of anionic and cationic radionuclide species in clayrocks lies in a detailed understanding of the phenomena governing Rn total concentration and speciation (dissolved, adsorbed) in the different types of pore spaces present in highly-compacted masses of permanently charged clay minerals. Work carried out on a specifically synthesized montmorillonite (a model for the clay mineral fraction in clayrocks) led to development, and preliminary experimental validation, of a conceptually coherent set of theoretical models (molecular dynamics, electrostatic double layer, thermodynamic) describing dissolved ion and water solvent behavior in this material. This work, complemented by the existing state of the art, provides a sound theoretical basis for explaining such important phenomena as anion exclusion, cation exchange and the diffusion behavior of anions, weakly sorbing cations and water tracers. Concerning the behavior of strongly sorbing and/or redox-reactive radionuclides in clay systems, project research improved understanding of the nature of sorption reactions and sorbed species structure for key radioelements, or analogues (U, Se, Eu, Sm, Yb, Nd) on the basal surfaces and in the interlayers of synthetic or purified clay minerals. A probable mechanism for Se(IV) retention by reduction to Se° in Fe2+-containing clays was brought to light; this same process was also studied on the Callovo-Oxfordien clayrock targeted by the French radwaste management program. The migration of most radionuclides in clayrocks, in particular the actinides, is limited by their strong sorption on rock mineral surfaces. Much effort was devoted in Funmig to improving understanding of this process on the clayrocks being studied in the Swiss, Belgian and French radwaste management programs. Specific attention was focused on (i) elucidating the effect of dissolved organic matter on Am(III), Th(IV), Eu(III) sorption on clayrock surfaces and (ii) determining the link between Kd measured on dispersed rock systems and the Kd operant in intact rock volumes, i.e. during diffusion. Regarding the latter question, results indicate that Kd values for ‘dispersed' and ‘intact' materials are quite similar for certain elements (Na, Sr, Cs, Co). On the other hand, Kd values obtained by modeling results of diffusion experiments involving strongly sorbing elements as Cs, Co and Eu were always significantly smaller than those predicted based on sorption data measured in corresponding batch systems. This is an area where additional research is being planned. A major effort was devoted to improving understanding of the effects of small-scale (?m to cm) clayrock structure and large-scale (dm to hm) mineralogical composition on radionuclide diffusion-retention. The program focusing on the small-scale produced a method for simulating the results of tracer diffusion in an intact rock based on the actual rock microstructure of the rock sample to be used in the diffusion experiment. This model was used to predict / inverse model the spatial distribution of highly sorbing tracers (Eu, Cu). This overall approach is also being used to understand how changes in mineralogical composition can affect the values of macroscopic diffusion parameters (De, tortuosity, anisiotropy). At a much larger scale, the results of (i) a geostatistical analysis of clayrock mineralogical variability and (ii) measurements of De and Kd dependence on mineralogy for Cs and Cl, were combined to create models of parameter variability at the formation scale. These m