Analytical results and sample locality map of stream-sediment, heavy mineral-concentrate, rock and water samples from the Skedaddle (CA-020- 612) and Dry Valley Rim (CA-020-615) Wilderness Study Areas, Lassen County, California, and Washoe County, Nevada

USGS Publications Warehouse

Adrian, B.M.; Frisken, J.G.; Bradley, L.A.; Taylor, Cliff D.; McHugh, J.B.

1987-01-01

In the summer of 1985, the U.S. Geological Survey conducted a reconnaissance geochemical survey of the Skedaddle (CA-020-612) and Dry Valley Rim (CA-020-615) Wilderness Study Areas in Lassen County, California, and Washoe County, Nevada.Skedaddle and Dry Valley Rim are contiguous wilderness study areas (WSA) located in the eastern part of the Modoc Plateau in Lassen County, northeastern California, and Washoe County, northwestern Nevada (fig. 1). The Skedaddle study area encompasses 39,420 acres and the Dry Valley Rim study area encompasses 54,480 acres of Bureau of Land Management administered public land about 25 mi east of Susanville, California. The Skedaddle study area is bounded on the east by the Skedaddle road, on the north by the Smoke Creek Road, on the south by the Wendel road, and on the west by the rim west of Wendel Canyon. The Dry Valley Rim study area is bounded on the east by the lower Smoke Creek road, the Dry Valley road, and the Pipe Springs Road. The northern boundary is the Smoke Creek Ranch road, the southern boundary the Wendel road, and the western boundary the east-side Skedaddle road. Access to the study areas is provided by several light-duty dirt roads and ways that join the boundary roads. Elevations range from 3,800 (1158 m) to 7,552 ft (2302 m). Steep rim rock walls and talus-covered canyons are common in the eastern third of the Dry Valley Rim study area, and the western third of the Skedaddle study area, while the majority of both study areas is gradually sloping, covered only by sparse sagebrush. Existing geologic maps that cover the two study areas consist of Lydon and others (I960), Bonham (1969), and Diggles and others (1986).The Skedaddle Wilderness Study Area consists of two parallel ridges, the Skedaddle Mountains and the Amedee Mountains. The ridges bound the Wendel and Spencer basins, an area of bleached and silicified rocks. Dry Valley Rim is a 17-mi (5.2 m)-long north-south-trending fault block that is situated 1,500 ft (457 m) above the Smoke Creek Desert to the east. The rim provides good exposure of the thick sequences of volcanic rocks that underlie the wilderness study area.The rocks of the study areas consist mostly of Tertiary basalt, andesite, and lahar with minor amounts of rhyolitic ash-flow tuff, rhyolite, and dacite. Surficial deposits consist of colluvium, alluvium, and talus, as well as aeolian, lacustrine, and fluvial deposits.

An Experimental Study on Normal Stress and Shear Rate Dependency of Basic Friction Coefficient in Dry and Wet Limestone Joints

NASA Astrophysics Data System (ADS)

Mehrishal, Seyedahmad; Sharifzadeh, Mostafa; Shahriar, Korosh; Song, Jae-Jon

2016-12-01

Among all parameters that affect the friction of rocks, variable normal stress and slip rate are the most important second-order parameters. The shear-rate- and normal-stress-dependent friction behavior of rock discontinuities may significantly influence the dynamic responses of rock mass. In this research, two limestone rock types, which were travertine and onyx marble with slickenside and grinded #80 surfaces, were prepared and CNL direct shear tests were performed on the joints under various shear conditions. The shearing rate varied from 0.1 to 50 mm/min under different normal stresses (from 2 to 30 % of UCS) in both dry and wet conditions. Experiments showed that the friction coefficient of slickensided and ground #80 surfaces of limestone increased with the increasing shear velocity and decreased with the increasing normal stress. Micro-asperity interlocking between ground #80 surfaces showed higher wear and an increase in friction coefficient ( µ) compared to slickensided surfaces. Slickensided samples with moist surfaces showed an increase in the coefficient of friction compared to dry surfaces; however, on ground #80 surfaces, the moisture decreased the coefficient of friction to a smaller value. Slickenside of limestone typically slides stably in a dry condition and by stick-slip on moist surfaces. The observed shear-rate- and normal-stress-dependent friction behavior can be explained by a similar framework to that of the adhesion theory of friction and a friction mechanism that involves the competition between microscopic dilatant slip and surface asperity deformation. The results have important implications for understanding the behavior of basic and residual friction coefficients of limestone rock surfaces.

Freeze-Thaw Cycle Test on Basalt, Diorite and Tuff Specimens with the Simulated Ground Temperature of Antarctica

NASA Astrophysics Data System (ADS)

Park, J.; Hyun, C.; Cho, H.; Park, H.

2010-12-01

Physical weathering caused by freeze-thaw action in cold regions was simulated with artificial weathering simulator in laboratory. Physical weathering of rock in cold regions usually depends on the temperature, rock type and moisture content. Then these three variables were considered in this study. The laboratory freeze-thaw tests were conducted on the three types of rocks, e.g. diorite, basalt and tuff, which are the major rock types around Sejong Station, King George Island, Antarctica. Nine core samples composed of three samples from each rock type were prepared in NX core, and 50 cycles of freeze-thaw test was carried out under dried and saturated water conditions. In this study, the physical weathering of rocks was investigated after each 10 cycles by measuring P-wave velocity, bulk density, effective porosity, Schmidt hardness and uniaxial compression strength(UCS). The experimental result of the diorite and the tuff specimens showed that P-wave velocity, bulk density, effective porosity, Schmidt hardness and UCS were gradually decreased as weathering progresses, but the result of the basalt specimens did not show typical trends due to the characteristics of irregular pore distribution and various pore sizes. Scanning electron microscopy(SEM) photographs of diorite, basalt and tuff specimens weathered in dried and saturated conditions were also acquired to investigate the role of water during physical weathering processes. The number and size of microcracks were increased as weathering progresses. This work was supported by the National Research Foundation of Korea(NRF) Grant(NRF-2010-0027753).

Gusev Crater on Mars: Wet and Dry

NASA Technical Reports Server (NTRS)

Yen, Albert; Gellert, Ralf; Morris, Richard

2008-01-01

The Mars Exploration Rover Spirit has traversed over 7.5 km in 1470 sols of operations at the Gusev Crater landing site. Chemical and mineralogical evidence from approximately 200 in-situ samples indicate various degrees of exposure to liquid water, from wet and saturated to dry and unaltered. (1) Six samples with concentrations of amorphous silica between 60 and 95 wt% were discovered in a small valley less than 50 meters in length. Associated enrichments in titanium oxide, relatively insoluble at low pH, suggest that these silica deposits formed as a result of acidic leaching processes. Liquid water interactions with these surface materials were necessary to remove cations solubilized in the low pH environment or to concentrate silica in solution prior to precipitation. (2) Hydrated ferric sulfates are found in subsurface deposits which have the unmistakable chemical signatures of nearby rocks. The movement of hydrothermal fluids and/or fumarolic vapors through local rocks prior to precipitation of these materials is suggested by these observations. (3) Goethite (alpha-FeOOH), a mineral phase which requires water to form, represents 20% to 35% of the iron in numerous rock samples (Clovis Class) on the West Spur of the Columbia Hills. Alteration of iron under aqueous conditions is clearly indicated by this presence of goethite. (4) Nearly isochemical signatures are found in elemental analyses of over ten distinct samples (Wishstone/Watchtower class rocks), yet the ratio of ferric iron to total iron varies from 0.4 to 0.95. Small quantities of water, insufficient to flush cations from the samples, were likely responsible for this weathering. (5) Bromine, a trace element readily mobilized by water, is found in high concentrations in certain rock interiors and is enhanced in subsurface soils, consistent with transport to localized cold traps by water thin-films. (6) Also relevant to the characterizing the role of liquid water is the discovery of an areally extensive ultramafic sequence of rocks where over 70% of the iron is in unaltered olivine and the ferric to total iron ratio is 0.1. This result indicates that certain materials at the martian surface have been protected from aqueous alteration.

Fault Frictional Stability in a Nuclear Waste Repository

NASA Astrophysics Data System (ADS)

Orellana, Felipe; Violay, Marie; Scuderi, Marco; Collettini, Cristiano

2016-04-01

Exploitation of underground resources induces hydro-mechanical and chemical perturbations in the rock mass. In response to such disturbances, seismic events might occur, affecting the safety of the whole engineering system. The Mont Terri Rock Laboratory is an underground infrastructure devoted to the study of geological disposal of nuclear waste in Switzerland. At the site, it is intersected by large fault zones of about 0.8 - 3 m in thickness and the host rock formation is a shale rock named Opalinus Clay (OPA). The mineralogy of OPA includes a high content of phyllosilicates (50%), quartz (25%), calcite (15%), and smaller proportions of siderite and pyrite. OPA is a stiff, low permeable rock (2×10-18 m2), and its mechanical behaviour is strongly affected by the anisotropy induced by bedding planes. The evaluation of fault stability and associated fault slip behaviour (i.e. seismic vs. aseismic) is a major issue in order to ensure the long-term safety and operation of the repository. Consequently, experiments devoted to understand the frictional behaviour of OPA have been performed in the biaxial apparatus "BRAVA", recently developed at INGV. Simulated fault gouge obtained from intact OPA samples, were deformed at different normal stresses (from 4 to 30 MPa), under dry and fluid-saturated conditions. To estimate the frictional stability, the velocity-dependence of friction was evaluated during velocity steps tests (1-300 μm/s). Slide-hold-slide tests were performed (1-3000 s) to measure the amount of frictional healing. The collected data were subsequently modelled with the Ruina's slip dependent formulation of the rate and state friction constitutive equations. To understand the deformation mechanism, the microstructures of the sheared gouge were analysed. At 7 MPa normal stress and under dry conditions, the friction coefficient decreased from a peak value of μpeak,dry = 0.57 to μss,dry = 0.50. Under fluid-saturated conditions and same normal stress, the friction coefficient decreased from a peak value of μpeak,sat = 0.45 to μss,sat = 0.34. Additionally, it has been observed that the weakening distance Dw is smaller under fluid- saturated conditions (˜4 mm) compared to dry conditions (˜6 mm). Results showed a linear decrease of both peak friction and steady state friction when normal stress increases. When fluid- saturation degree of gouges is reduced, gouge samples underwent a transition from velocity strengthening to velocity weakening behaviour, thus indicating a potentially unstable frictional behaviour of the fault. Furthermore, under both saturated and dry conditions, the frictional healing rate showed a low recovery of the friction coefficient under different holding times. Our experiments indicate that the frictional behaviour of Opalinus Clay is characterized by complex processes depending upon normal stress, sliding velocity, and saturation degree of the samples. This complexity highlights the need for further experiments in order to better evaluate the seismic risk during long-term nuclear waste disposal within the OPA clay formation.

Seed dormancy and persistent sediment seed banks of ephemeral freshwater rock pools in the Australian monsoon tropics

PubMed Central

Cross, Adam T.; Turner, Shane R.; Renton, Michael; Baskin, Jerry M.; Dixon, Kingsley W.; Merritt, David J.

2015-01-01

Background and Aims Rock pools are small, geologically stable freshwater ecosystems that are both hydrologically and biologically isolated. They harbour high levels of plant endemism and experience environmental unpredictability driven by the presence of water over variable temporal scales. This study examined the hypothesis that the sediment seed bank in monsoon tropical freshwater rock pools would persist through one or more periods of desiccation, with seed dormancy regulating germination timing in response to rock pool inundation and drying events. Methods Seeds were collected from seven dominant rock pool species, and germination biology and seed dormancy were assessed under laboratory conditions in response to light, temperature and germination stimulators (gibberellic acid, karrikinolide and ethylene). Field surveys of seedling emergence from freshwater rock pools in the Kimberley region of Western Australia were undertaken, and sediment samples were collected from 41 vegetated rock pools. Seedling emergence and seed bank persistence in response to multiple wetting and drying cycles were determined. Key Results The sediment seed bank of individual rock pools was large (13 824 ± 307 to 218 320 ± 42 412 seeds m−2 for the five species investigated) and spatially variable. Seedling density for these same species in the field ranged from 13 696 to 87 232 seedlings m−2. Seeds of rock pool taxa were physiologically dormant, with germination promoted by after-ripening and exposure to ethylene or karrikinolide. Patterns of seedling emergence varied between species and were finely tuned to seasonal temperature and moisture conditions, with the proportions of emergent seedlings differing between species through multiple inundation events. A viable seed bank persisted after ten consecutive laboratory inundation events, and seeds retained viability in dry sediments for at least 3 years. Conclusions The persistent seed bank in freshwater rock pools is likely to provide resilience to plant communities against environmental stochasticity. Since rock pool communities are often comprised of highly specialized endemic and range-restricted species, sediment seed banks may represent significant drivers of species persistence and diversification in these ecosystems. PMID:25660345

A gas sampling system for withdrawing humid gases from deep boreholes

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

Rousseau, J.P.; Thordarson, W.; Kurzmack, M.A.

A gas sampling system, designed to withdraw nearly vapor-saturated gases (93 to 100% relative humidity) from deep, unsaturated zone boreholes, was developed by the U.S. Geological Survey for use in the unsaturated zone borehole instrumentation and monitoring program at Yucca Mountain, Nye County, Nevada. This gas sampling system will be used to: (1) sample formation rock gases in support of the unsaturated zone hydrochemical characterization program; and (2) verify downhole, thermocouple psychrometer measurements of water potential in support of the unsaturated zone borehole instrumentation and monitoring program. Using this sampling system, nearly vapor-saturated formation rock-gases can be withdrawn from deepmore » boreholes without condensing water vapor in the sampling tubes, and fractionating heavy isotopes of oxygen, hydrogen, and carbon. The sampling system described in this paper uses a dry carrier-gas (nitrogen) to lower the dew point temperature of the formation rock-gas at its source. Mixing of the dry carrier gas with the source gas takes place inside a specially designed downhole instrument station apparatus (DISA). Nitrogen inflow is regulated in a manner that lowers the dew point temperature of the source gas to a temperature that is colder than the coldest temperature that the mixed gas will experience in moving from warmer, deeper depths, to colder, shallower depths near the land surface. A test of this gas sampling system was conducted in December, 1992, in a 12.2 meter deep borehole that was instrumented in October, 1991. The water potential calculated using this system reproduced in-situ measurements of water potential to within five percent of the average value, as recorded by two thermocouple psychrometers that had been in operation for over 12 months.« less

Mechanical Behavior and Microcrack Development in Nominally Dry Synthetic Salt-rock During Cyclic Loading

NASA Astrophysics Data System (ADS)

Ding, J.; Chester, F. M.; Chester, J. S.; Zhu, C.; Shen, X.; Arson, C. F.

2016-12-01

Synthetic salt-rock is produced through uniaxial consolidation of sieved granular salt (0.3-0.355 mm grain diam.) at 75-107 MPa pressure and 100-200 0 C for 15 min duration, to produce low porosity (3%-6%) aggregates. Based on microstructural observations, consolidation mechanisms are grain rearrangement, intragranular plastic flow, and minor microfracture and recrystallization. Following consolidation, the salt-rock is deformed by cyclic, triaxial loading at room temperature and 4 MPa confining pressure to investigate microfracture development, closure and healing effects on elastic properties and flow strength. Load cycles are performed within the elastic regime, up to yielding, and during steady ductile flow. The mechanical properties are determined using an internal load cell and strain gages bonded to the samples. Elastic properties vary systematically during deformation reflecting cracking and pore and grain shape changes. Between triaxial load cycles, samples are held at isostatic loads for durations up to one day to determine healing rates and strength recovery; a change in mechanical behavior is observed when significant healing is induced. The microstructures of all samples are characterized before and after cyclic loading using optical microscopy. The consolidation and cyclic triaxial tests, and optical microscopy investigations, are conducted in a controlled low-humidity environment to ensure nominally dry conditions. The microstructures of samples from different stages of cyclic triaxial deformation indicate that intracrystalline plasticity, accompanied by minor recovery by recrystallization, is dominant; but, grain-boundary crack opening also becomes significant. Grain-boundary microcracks have preferred orientations that are sub-parallel to the load axis. The stress-strain behavior correlates with microcrack fabrics and densities during cyclic loading. These experiments are used to both inform and test continuum damage mechanics models of salt-rock deformation in the semibrittle domain, as well as to help design and optimize salt-rock storage facilities.

Physical property measurements on analog granites related to the joint verification experiment

NASA Astrophysics Data System (ADS)

Martin, Randolph J., III; Coyner, Karl B.; Haupt, Robert W.

1990-08-01

A key element in JVE (Joint Verification Experiment) conducted jointly between the United States and the USSR is the analysis of the geology and physical properties of the rocks in the respective test sites. A study was initiated to examine unclassified crystalline rock specimens obtained from areas near the Soviet site, Semipalatinsk and appropriate analog samples selected from Mt. Katadin, Maine. These rocks were also compared to Sierra White and Westerly Granite which have been studied in great detail. Measurements performed to characterize these rocks were: (1) Uniaxial strain with simultaneous compressional and shear wave velocities; (2) Hydrostatic compression to 150 MPa with simultaneous compressional and shear wave velocities; (3) Attenuation measurements as a function of frequency and strain amplitude for both dry and water saturated conditions. Elastic moduli determined from the hydrostatic compression and uniaxial strain test show that the rock matrix/mineral properties were comparable in magnitudes which vary within 25 percent from sample to sample. These properties appear to be approximately isotropic, especially at high pressures. However, anisotropy evident for certain samples at pressures below 35 MPa is attributed to dominant pre-existing microcrack populations and their alignments. Dependence of extensional attenuation and Young's modulus on strain amplitude were experimentally determined for intact Sierra White granite using the hysteresis loop technique.

Detailed Aggregate Resources Study, Dry Lake Valley, Nevada.

DTIC Science & Technology

1981-05-29

LOCAL SAND SOURCES IGENERALLY CYLINDERS. DRYING SHRINKAGE I COLLECTED WITHIN A FEW MILES OF CORRESPONDING LEDGE-ROCK SOURCES) SUPPLIED FINE MENS...COMPRESSIVE AND TENSILE STh LEDGE-ROCK SOURCES SUPPLIED COARSE AGGREGATES; LOCAL SAND SOURCES IGENERALLY CYLINDERS. DRYING SHRINKAGE COLLECTED WITHIN A FEW

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

PubMed

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

2008-10-01

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

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

NASA Astrophysics Data System (ADS)

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

2008-10-01

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

Diversity of micro-fungi in an Antarctic dry valley

NASA Technical Reports Server (NTRS)

Baublis, J. A.; Wharton, R. A. Jr; Volz, P. A.; Wharton RA, J. r. (Principal Investigator)

1991-01-01

The fungal microflora of a dry valley in Southern Victoria Land near McMurdo Sound, Antarctica, was investigated. Samples were collected from introduced objects such as a mummified penguin and spent chewing tobacco in addition to the sparse soil found in rock fissures, isolated moss colonies, shoreline deposit materials, CaCO3 precipitates, and microbial mat debris obtained from the frozen surface of the lake in the basin of Taylor Valley. Using conventional media and techniques, all collection sites yielded populations of yeasts and filamentous fungi. Water samples and live microbial mats from beneath the lake ice yielded species of fungi along with an abundance of bacteria.

Seed dormancy and persistent sediment seed banks of ephemeral freshwater rock pools in the Australian monsoon tropics.

PubMed

Cross, Adam T; Turner, Shane R; Renton, Michael; Baskin, Jerry M; Dixon, Kingsley W; Merritt, David J

2015-04-01

Rock pools are small, geologically stable freshwater ecosystems that are both hydrologically and biologically isolated. They harbour high levels of plant endemism and experience environmental unpredictability driven by the presence of water over variable temporal scales. This study examined the hypothesis that the sediment seed bank in monsoon tropical freshwater rock pools would persist through one or more periods of desiccation, with seed dormancy regulating germination timing in response to rock pool inundation and drying events. Seeds were collected from seven dominant rock pool species, and germination biology and seed dormancy were assessed under laboratory conditions in response to light, temperature and germination stimulators (gibberellic acid, karrikinolide and ethylene). Field surveys of seedling emergence from freshwater rock pools in the Kimberley region of Western Australia were undertaken, and sediment samples were collected from 41 vegetated rock pools. Seedling emergence and seed bank persistence in response to multiple wetting and drying cycles were determined. The sediment seed bank of individual rock pools was large (13 824 ± 307 to 218 320 ± 42 412 seeds m(-2) for the five species investigated) and spatially variable. Seedling density for these same species in the field ranged from 13 696 to 87 232 seedlings m(-2). Seeds of rock pool taxa were physiologically dormant, with germination promoted by after-ripening and exposure to ethylene or karrikinolide. Patterns of seedling emergence varied between species and were finely tuned to seasonal temperature and moisture conditions, with the proportions of emergent seedlings differing between species through multiple inundation events. A viable seed bank persisted after ten consecutive laboratory inundation events, and seeds retained viability in dry sediments for at least 3 years. The persistent seed bank in freshwater rock pools is likely to provide resilience to plant communities against environmental stochasticity. Since rock pool communities are often comprised of highly specialized endemic and range-restricted species, sediment seed banks may represent significant drivers of species persistence and diversification in these ecosystems. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Strength/Brittleness Classification of Igneous Intact Rocks Based on Basic Physical and Dynamic Properties

NASA Astrophysics Data System (ADS)

Aligholi, Saeed; Lashkaripour, Gholam Reza; Ghafoori, Mohammad

2017-01-01

This paper sheds further light on the fundamental relationships between simple methods, rock strength, and brittleness of igneous rocks. In particular, the relationship between mechanical (point load strength index I s(50) and brittleness value S 20), basic physical (dry density and porosity), and dynamic properties (P-wave velocity and Schmidt rebound values) for a wide range of Iranian igneous rocks is investigated. First, 30 statistical models (including simple and multiple linear regression analyses) were built to identify the relationships between mechanical properties and simple methods. The results imply that rocks with different Schmidt hardness (SH) rebound values have different physicomechanical properties or relations. Second, using these results, it was proved that dry density, P-wave velocity, and SH rebound value provide a fine complement to mechanical properties classification of rock materials. Further, a detailed investigation was conducted on the relationships between mechanical and simple tests, which are established with limited ranges of P-wave velocity and dry density. The results show that strength values decrease with the SH rebound value. In addition, there is a systematic trend between dry density, P-wave velocity, rebound hardness, and brittleness value of the studied rocks, and rocks with medium hardness have a higher brittleness value. Finally, a strength classification chart and a brittleness classification table are presented, providing reliable and low-cost methods for the classification of igneous rocks.

Influence of Water Content on Mechanical Properties of Rock in Both Saturation and Drying Processes

NASA Astrophysics Data System (ADS)

Zhou, Zilong; Cai, Xin; Cao, Wenzhuo; Li, Xibing; Xiong, Cheng

2016-08-01

Water content has a pronounced influence on the properties of rock materials, which is responsible for many rock engineering hazards, such as landslides and karst collapse. Meanwhile, water injection is also used for the prevention of some engineering disasters like rock-bursts. To comprehensively investigate the effect of water content on mechanical properties of rocks, laboratory tests were carried out on sandstone specimens with different water contents in both saturation and drying processes. The Nuclear Magnetic Resonance technique was applied to study the water distribution in specimens with variation of water contents. The servo-controlled rock mechanics testing machine and Split Hopkinson Pressure Bar technique were used to conduct both compressive and tensile tests on sandstone specimens with different water contents. From the laboratory tests, reductions of the compressive and tensile strength of sandstone under static and dynamic states in different saturation processes were observed. In the drying process, all of the saturated specimens could basically regain their mechanical properties and recover its strength as in the dry state. However, for partially saturated specimens in the saturation and drying processes, the tensile strength of specimens with the same water content was different, which could be related to different water distributions in specimens.

Thermal conductivity of water-saturated rocks from the KTB pilot hole at temperatures of 25 to 300°C

USGS Publications Warehouse

Pribnow, D.; Williams, C.F.; Sass, J.H.; Keating, R.

1996-01-01

The conductivitites of selected gneiss (two) and amphibolite (one) core samples have been measured under conditions of elevated temperature and pressure with a needle-probe. Water-saturated thermal conductivity measurements spanning temperatures from 25 to 300??C and hydrostatic pressures of 0.1 and 34 MPa confirm the general decrease in conductivity with increasing temperature but deviate significantly from results reported from measurements on dry samples over the same temperature range. The thermal conductivity of water-saturated amphibolite decreases with temperature at a rate approximately 40% less than the rate for dry amphibolite, and the conductivity of water-saturated gneiss decreases at a rate approximately 20% less than the rate for dry gneiss. The available evidence points to thermal cracking as the primary cause of the more rapid decrease in dry thermal conductivity with temperature. The effects of thermal cracking were also observed in the water-saturated samples but resulted in a net decrease in room-temperature conductivity of less than 3%. These results highlight the importance of duplicating in-situ conditions when determining thermal conductivity for the deep crust.

Rock-forming metals and Pb in modern Alaskan snow

USGS Publications Warehouse

Hinkley, Todd K.

1993-01-01

Metal concentrations in annual and subannual increments of snowpack from the accumulation zone of a south central Alaska glacier indicate that the deposition of Pb with and upon snow is decoupled from that of rock dusts. Rock dusts accumulate, apparently as dry deposition, on the topmost, exposed surfaces of snowpacks in spring and summer, whereas Pb does not. Pb concentration is elevated throughout the latest one third of an annual snowpack, whereas that of rock dusts is not. For whole-year snowpacks, there is a generally sympathetic relationship among concentration of Pb, concentration of rock dust, degree of dominance of rock dusts over ocean solutes, and ferromagnesian character of the rock dusts; however, the fractional abundance of Pb in whole year samples may decrease when rock dust masses become large and/or when rock dusts dominate most strongly over salts. The metal suite chosen to characterize rock dusts and to distinguish them from ocean solutes gives detailed information about rock type of dust source areas and about the nature of the degraded rock products that are taken up, transported, and deposited by the atmosphere. Rock dusts are present at concentrations of only about 300 nanograms (ng) of dust per gram of snow in the Alaskan snowpacks. Concentrations of Pb in the Alaska snow samples are moderate, ranging from 0.1 to 0.3 ng Pb/g snow. This contrasts with larger Pb concentrations of 0.4 to 0.9 ng Pb/g snow in whole-year snowpack samples from the Sierra Nevada, California; with similar to smaller concentrations from north and south Greenland of about 0.04 ng Pb/g snow or less, and about 0.2 ng Pb/g snow or less, respectively, and with much smaller concentrations from Antarctica, now believed to range from a minimum of about 0.001 to a maximum of 0.005 (or 0.01) ng Pb/g snow.

Electrical properties of dry rocks

NASA Technical Reports Server (NTRS)

Morrison, H.

1973-01-01

The mechanism by which atmospheric moisture affects the conductivity and dielectric constant of rock specimens was studied in time and frequency domains. It is suggested that adsorbed water molecules alter the surface conductivity in a manner similar to that observed in semiconductors and insulators. Powdered basalts show a low-frequency dispersion produced by the atmospheric moisture remaining in the pore system of the sample in a high vacuum; this effect is attributed to isolated adsorption centers. Simulated lunar permafrost at 100 K and a vacuum of 10 to the -8th power torr together with data on lunar samples contaminated with atmospheric moisture and the dielectric properties of ice at various temperatures indicate that, if permafrost exists in the moon it should present a relaxation peak at approximately 300 Hz; for temperatures up to 263 K it may go up to 20 KHz. It is concluded that in order to have electrical steady state conditions in rock samples it is necessary to have volume charge accumulations at interfaces within the sample and at the electrode sample interface. A method for measuring heterogeneous dielectrics with non-negligible ohmic and dielectric conductivities is proposed and experimentally verified.

Water soluble cations and the fluvial history of Mars

NASA Technical Reports Server (NTRS)

Silverman, M. P.; Munoz, E. F.

1975-01-01

The electrical conductivity and water soluble Na, K, Ca, and Mg of aqueous solutions of terrestrial soils and finely divided igneous and metamorphic rocks were determined. Soils from dry terrestrial basins with a history of water accumulation as well as soils from the topographic lows of valleys accumulated water soluble cations, particularly Na and Ca. These soils as a group can be distinguished from the rocks or a second group of soils (leached upland soils and soils from sites other than the topographic lows of valleys) by significant differences in their mean electrical conductivity and water-soluble Na + Ca content. Similar measurements on multiple samples from the surface of Mars, collected by an automated long-range roving vehicle along a highlands-to-basin transect at sites with morphological features resembling dry riverlike channels, are suggested to determine the fluvial history of the planet.

Use of a probabilistic neural network to reduce costs of selecting construction rock

USGS Publications Warehouse

Singer, Donald A.; Bliss, James D.

2003-01-01

Rocks used as construction aggregate in temperate climates deteriorate to differing degrees because of repeated freezing and thawing. The magnitude of the deterioration depends on the rock's properties. Aggregate, including crushed carbonate rock, is required to have minimum geotechnical qualities before it can be used in asphalt and concrete. In order to reduce chances of premature and expensive repairs, extensive freeze-thaw tests are conducted on potential construction rocks. These tests typically involve 300 freeze-thaw cycles and can take four to five months to complete. Less time consuming tests that (1) predict durability as well as the extended freeze-thaw test or that (2) reduce the number of rocks subject to the extended test, could save considerable amounts of money. Here we use a probabilistic neural network to try and predict durability as determined by the freeze-thaw test using four rock properties measured on 843 limestone samples from the Kansas Department of Transportation. Modified freeze-thaw tests and less time consuming specific gravity (dry), specific gravity (saturated), and modified absorption tests were conducted on each sample. Durability factors of 95 or more as determined from the extensive freeze-thaw tests are viewed as acceptable—rocks with values below 95 are rejected. If only the modified freeze-thaw test is used to predict which rocks are acceptable, about 45% are misclassified. When 421 randomly selected samples and all four standardized and scaled variables were used to train aprobabilistic neural network, the rate of misclassification of 422 independent validation samples dropped to 28%. The network was trained so that each class (group) and each variable had its own coefficient (sigma). In an attempt to reduce errors further, an additional class was added to the training data to predict durability values greater than 84 and less than 98, resulting in only 11% of the samples misclassified. About 43% of the test data was classed by the neural net into the middle group—these rocks should be subject to full freeze-thaw tests. Thus, use of the probabilistic neural network would meanthat the extended test would only need be applied to 43% of the samples, and 11% of the rocks classed as acceptable would fail early.

Continuous Nanoclimate Data (1985-1988) from the Ross Desert (McMurdo Dry Valleys) Cryptoendolithic Microbial Ecosystem

NASA Technical Reports Server (NTRS)

McKay, Christopher P.; Nienow, James; Meyer, Michael A.; Friedmann, E. Imre

1993-01-01

We have collected year-round nanoclimate data for the cryptoendolithic microbial habitat in sandstones of the Ross desert, Antarctica, obtained with an Argos satellite data system. Data for two sites in the McMurdo Dry Valleys are available: Linnaeus Terrace, January 1985 to June 1988, and Battleship Promontory, 1986-1987. The focus of this research is ecological, and hence year-round environmental data have been obtained for the ambient environment as well as for conditions within the rock. Using data from the summer, we compare the conditions inside the rock to the outside weather. This demonstrates how the rock provides a shelter for the endolithic microbial community. The most important property of the rock is that it absorbs the summer sunlight, thereby warming up to temperatures above freezing. This warming allows snowmelt to seep into the rock, and the moisture level in the rocks can remain high for weeks against loss to the dry environment.

Lithological Influences on Occurrence of High-Fluoride Waters in The Central Kenya Rift

NASA Astrophysics Data System (ADS)

Olaka, L. A.; Musolff, A.; Mulch, A.; Olago, D.; Odada, E. O.

2013-12-01

Within the East African rift, groundwater recharge results from the complex interplay of geology, land cover, geomorphology, climate and on going volcano-tectonic processes across a broad range of spatial and temporal scales. The interrelationships between these factors create complex patterns of water availability, reliability and quality. The hydrochemical evolution of the waters is further complex due to the different climatic regimes and geothermal processes going on in this area. High fluoridic waters within the rift have been reported by few studies, while dental fluorosis is high among the inhabitants of the rift. The natural sources of fluoride in waters can be from weathering of fluorine bearing minerals in rocks, volcanic or fumarolic activities. Fluoride concentration in water depends on a number of factors including pH, temperature, time of water-rock formation contact and geochemical processes. Knowledge of the sources and dispersion of fluoride in both surface and groundwaters within the central Kenya rift and seasonal variations between wet and dry seasons is still poor. The Central Kenya rift is marked by active tectonics, volcanic activity and fumarolic activity, the rocks are majorly volcanics: rhyolites, tuffs, basalts, phonolites, ashes and agglomerates some are highly fractured. Major NW-SE faults bound the rift escarpment while the rift floor is marked by N-S striking faults We combine petrographic, hydrochemistry and structural information to determine the sources and enrichment pathways of high fluoridic waters within the Naivasha catchment. A total of 120 water samples for both the dry season (January-February2012) and after wet season (June-July 2013) from springs, rivers, lakes, hand dug wells, fumaroles and boreholes within the Naivasha catchment are collected and analysed for fluoride, physicochemical parameters and stable isotopes (δ2 H, δ18 O) in order to determine the origin and evolution of the waters. Additionally, 30 soil and rock samples were also collected and analysed for fluoride, and rock samples were subjected to petrographic investigations and X-ray diffraction. The fluoride levels in surface and groundwater for the dry season range from 0.019 - 50.14 mg/L, on average above the WHO permissible limit. The high fluoride occurs both in the lake and groundwater. Preliminary petrographic studies show considerable fluoride in micas. The study is on-going and plans to present the relative abundances of fluoride in the lithology as the sources and the fluoride enrichment pathways of the groundwater within the Central Kenya rift.

Developing a shale heterogeneity index to predict fracture response in the Mancos Shale

NASA Astrophysics Data System (ADS)

DeReuil, Aubry; Birgenheier, Lauren; McLennan, John

2017-04-01

The interplay between sedimentary heterogeneity and fracture propagation in mudstone is crucial to assess the potential of low permeability rocks as unconventional reservoirs. Previous experimental research has demonstrated a relationship between heterogeneity and fracture of brittle rocks, as discontinuities in a rock mass influence micromechanical processes such as microcracking and strain localization, which evolve into macroscopic fractures. Though numerous studies have observed heterogeneity influencing fracture development, fundamental understanding of the entire fracture process and the physical controls on this process is still lacking. This is partly due to difficulties in quantifying heterogeneity in fine-grained rocks. Our study tests the hypothesis that there is a correlation between sedimentary heterogeneity and the manner in which mudstone is fractured. An extensive range of heterogeneity related to complex sedimentology is represented by various samples from cored intervals of the Mancos Shale. Samples were categorized via facies analysis consisting of: visual core description, XRF and XRD analysis, SEM and thin section microscopy, and reservoir quality analysis that tested porosity, permeability, water saturation, and TOC. Systematic indirect tensile testing on a broad variety of facies has been performed, and uniaxial and triaxial compression testing is underway. A novel tool based on analytically derived and statistically proven relationships between sedimentary geologic and geomechanical heterogeneity is the ultimate result, referred to as the shale heterogeneity index. Preliminary conclusions from development of the shale heterogeneity index reveal that samples with compositionally distinct bedding withstand loading at higher stress values, while texturally and compositionally homogeneous, bedded samples fail at lower stress values. The highest tensile strength results from cemented Ca-enriched samples, medial to high strength samples have approximately equivalent proportions of Al-Ca-Si compositions, while Al-rich samples have consistently low strength. Moisture preserved samples fail on average at approximately 5 MPa lower than dry samples of similar facies. Additionally, moisture preserved samples fail in a step-like pattern when tested perpendicular to bedding. Tensile fractures are halted at heterogeneities and propagate parallel to bedding planes before developing a through-going failure plane, as opposed to the discrete, continuous fractures that crosscut dry samples. This result suggests that sedimentary heterogeneity plays a greater role in fracture propagation in moisture preserved samples, which are more indicative of in-situ reservoir conditions. Stress-strain curves will be further analyzed, including estimation of an energy released term based on post-failure response, and an estimation of volume of cracking measure on the physical fracture surface.

Electrical conductivity measurement of granulite under mid- to lower crustal pressure-temperature conditions

NASA Astrophysics Data System (ADS)

Fuji-ta, K.; Katsura, T.; Tainosho, Y.

2004-04-01

We have developed a technique to measure electrical conductivity of crustal rocks with relatively low conductivity and complicated mineral components in order to compare with results given by magneto-telluric (MT) measurements. A granulite from Hidaka metamorphic belt (HMB) in Hokkaido, Japan at high temperature and pressure conditions was obtained. The granulite sample was ground and sintered under the conditions similar to those of mid- to lower crust. We have observed smooth and reversible change of conductivity with temperature up to about 900 K at 1 GPa. The results were consistent with the electrical conductivity structures suggested by the MT data analysis. Considering pore fluid conduction mechanism or the role of accessory minerals in the rock, the mechanisms of electrical conductivity paths in dry or basic rocks should be reconsidered.

Characterization of 15 selected coccal bacteria isolated from Antarctic rock and soil samples from the McMurdo-Dry Valleys (South-Victoria Land)

NASA Technical Reports Server (NTRS)

Siebert, J.; Hirsch, P.; Friedmann, E. I. (Principal Investigator)

1988-01-01

Approximately 1500 cultures of microorganisms were isolated from rocks and soils of the Ross Desert (McMurdo-Dry Valleys). From these, 15 coccoid strains were chosen for more detailed investigation. They were characterized by morphological, physiological and chemotaxonomical properties. All isolates were Gram-positive, catalase-positive and nonmotile. Six strains showed red pigmentation and could be identified as members of the genera Micrococcus (M. roseus, M. agilis) or Deinococcus. In spite of their coccoid morphology, the remaining nine strains had to be associated with coryneform bacteria (Arthrobacter, Brevibacterium), because of their cell wall composition and G+C ratios. Most of the strains were psychrotrophic, but one strain was even obligately psychrophilic, with a temperature maximum below 20 degrees C. Red cocci had in vitro pH optima above 9.0 although they generally originated from acid samples. Most isolates showed a preference for sugar alcohols and organic acids, compounds which are commonly known to be released by lichens, molds and algae, the other components of the cryptoendolithic ecosystem. These properties indicate that our strains are autochthonous members of the natural Antarctic microbial population.

Explosion Amplitude Reduction due to Fractures in Water-Saturated and Dry Granite

NASA Astrophysics Data System (ADS)

Stroujkova, A. F.; Leidig, M.; Bonner, J. L.

2013-12-01

Empirical observations made at the Semipalatinsk Test Site suggest that nuclear tests in the fracture zones left by previous explosions ('repeat shots') show reduced seismic amplitudes compared to the nuclear tests in virgin rocks. Likely mechanisms for the amplitude reduction in the repeat shots include increased porosity and reduced strength and elastic moduli, leading to pore closing and frictional sliding. Presence of pore water significantly decreases rock compressibility and strength, thus affecting seismic amplitudes. A series of explosion experiments were conducted in order to define the physical mechanism responsible for the amplitude reduction and to quantify the degree of the amplitude reduction in fracture zones of previously detonated explosions. Explosions in water-saturated granite were conducted in central New Hampshire in 2011 and 2012. Additional explosions in dry granite were detonated in Barre, VT in 2013. The amplitude reduction is different between dry and water-saturated crystalline rocks. Significant reduction in seismic amplitudes (by a factor of 2-3) in water-saturated rocks was achieved only when the repeat shot was detonated in the extensive damage zone created by a significantly larger (by a factor of 5) explosion. In case where the first and the second explosions were similar in yield, the amplitude reduction was relatively modest (5-20%). In dry rocks the amplitude reduction reached a factor of 2 even in less extensive damage zones. In addition there are differences in frequency dependence of the spectral amplitude ratios between explosions in dry and water-saturated rocks. Thus the amplitude reduction is sensitive to the extent of the damage zone as well as the pore water content.

Internal friction quality-factor Q under confining pressure. [of lunar rocks

NASA Technical Reports Server (NTRS)

Tittmann, B. R.; Ahlberg, L.; Nadler, H.; Curnow, J.; Smith, T.; Cohen, E. R.

1977-01-01

It has been found in previous studies that small amounts of adsorbed volatiles can have a profound effect on the internal friction quality-factor Q of rocks and other porous media. Pandit and Tozer (1970) have suggested that the laboratory-measured Q of volatile-free rocks should be similar to the in situ seismic Q values of near-surface lunar rocks which according to Latham et al. (1970) are in the range of 3000-5000. Observations of dramatic increases in Q with outgassing up to values approaching 2000 in the seismic frequency range confirm this supposition. Measurements under confining pressures with the sample encapsulated under hard vacuum are reported to aid in the interpretation of seismic data obtained below the lunar surface. It has been possible to achieve in the experiments Q values just under 2000 at about 1 kbar for a terrestrial analog of lunar basalt. It was found that a well-outgassed sample maintains a high Q whereas one exposed to moisture maintains a low Q as the confining pressure is raised to 2.5 kbar. This result suggests that volatiles can indeed affect Q when cracks are partially closed and the high lunar seismic Q values reported are concomitant with very dry rock down to depths of at least 50 km.

77 FR 59599 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-28

.... Applicants: Dry Lake Wind Power II LLC, Central Maine Power Company, Flat Rock Windpower II LLC, Flat Rock Windpower LLC, Elk River Windfarm, LLC, Iberdrola Renewables, LLC, Dillion Wind LLC, Dry Lake Wind Power, LLC, Shiloh I Wind Project, LLC, Mountain View Power Partners III, LLC, Blue [[Page 59600

Mechanical Behavior of Low Porosity Carbonate Rock: From Brittle Creep to Ductile Creep.

NASA Astrophysics Data System (ADS)

Nicolas, A.; Fortin, J.; Gueguen, Y.

2014-12-01

Mechanical compaction and associated porosity reduction play an important role in the diagenesis of porous rocks. They may also affect reservoir rocks during hydrocarbon production, as the pore pressure field is modified. This inelastic compaction can lead to subsidence, cause casing failure, trigger earthquake, or change the fluid transport properties. In addition, inelastic deformation can be time - dependent. In particular, brittle creep phenomena have been deeply investigated since the 90s, especially in sandstones. However knowledge of carbonates behavior is still insufficient. In this study, we focus on the mechanical behavior of a 14.7% porosity white Tavel (France) carbonate rock (>98% calcite). The samples were deformed in a triaxial cell at effective confining pressures ranging from 0 MPa to 85 MPa at room temperature and 70°C. Experiments were carried under dry and water saturated conditions in order to explore the role played by the pore fluids. Two types of experiments have been carried out: (1) a first series in order to investigate the rupture envelopes, and (2) a second series with creep experiments. During the experiments, elastic wave velocities (P and S) were measured to infer crack density evolution. Permeability was also measured during creep experiments. Our results show two different mechanical behaviors: (1) brittle behavior is observed at low confining pressures, whereas (2) ductile behavior is observed at higher confining pressures. During creep experiments, these two behaviors have a different signature in term of elastic wave velocities and permeability changes, due to two different mechanisms: development of micro-cracks at low confining pressures and competition between cracks and microplasticity at high confining pressure. The attached figure is a summary of 20 triaxial experiments performed on Tavel limestone under different conditions. Stress states C',C* and C*' and brittle strength are shown in the P-Q space: (a) 20°C and dry, (b) 20°C and water saturated samples, (c) 70°C dry and (d) summary of all the experiments. Three regimes of inelastic and failure modes are observed: brittle failure, shear-enhanced compaction and dilatant cataclastic flow.

Acoustic Fluidization and the Extraordinary Mobility of Sturzstroms

NASA Astrophysics Data System (ADS)

Collins, G. S.; Melosh, H. J.

2002-12-01

Sturzstroms are a rare category of rock avalanche that travel vast horizontal distances with only a comparatively small vertical drop in height. Their extraordinary mobility appears to be a consequence of sustained fluid-like behavior during motion that persists even for driving stresses well below those normally associated with large rock avalanches. One mechanism with the potential for explaining this temporary increase in the mobility of rock debris is acoustic fluidization; where transient, high-frequency pressure fluctuations, generated during the initial collapse and subsequent flow of a mass of rock debris, may locally relieve overburden stresses in the rock mass and thus reduce the frictional resistance to slip between fragments. Here we will present the acoustic fluidization model for the mechanics of sturzstroms, and discuss the conditions under which this process may sustain fluid-like flow of large rock avalanches at low driving stresses. Our work has focused on developing equations for describing the temporal and spatial evolution of acoustic energy within a mass of dry rock debris. We apply this model to the specific process of large, dry rock avalanches. To solve the complex system of equations we have: (1) sought steady state solutions to investigate the circumstances under which acoustic fluidization might facilitate fluid-like motion of the debris at low driving stresses; and (2) simulated the flow of dry rock debris in the presence of acoustic vibrations using a hydrocode, to test the stability of the steady state solutions, investigate the effect of initial conditions and study the avalanche termination process. Results from our modeling work are consistent with the characteristic observations of sturzstroms on Earth. They predict that, under realistic conditions, the flow of a mass of dry rock debris can retain and regenerate enough acoustic energy to perpetuate its own motion, even at very low slope angles; thereby explaining the peculiar long-runout of large rock avalanches. Observations of fluid-like behavior of sturzstroms are supported by our modeling work. The predicted velocity profile through the acoustically fluidized rock avalanche is parabolic; the sturzstrom flows with an effective viscosity that is almost independent of depth within the rock avalanche.

9. Photograph of a photograph in possession of Rock Island ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. Photograph of a photograph in possession of Rock Island Arsenal Historical Office. SOUTH ELEVATION AFTER ADDITION OF HOSE DRYING TOWER. DATED SEPTEMBER 26, 1919. - Rock Island Arsenal, Building No. 225, Rodman Avenue between Flagler Street & Gillespie Avenue, Rock Island, Rock Island County, IL

Salt weathering on Mars

NASA Astrophysics Data System (ADS)

Jagoutz, E.

Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974). However, irrespectively of the climatic environment a liquid brine is a necessity for salt induced fragmentation of rocks. If salt weathering is responsible for the fragmented rocks on the Martian surface it implies a temporary present of liquid H_2O. However, due to the present dry atmosphere on Mars brines can only be present in restricted places without being in equilibrium with the atmosphere (Clark and van Hart 1980). M. C. Malin (1974) JGR Vol 79,26 p 3888-3894 B. C. Clark and D. C. vanHart (1980) ICARUS 45, 370-378

High-frequency rock temperature data from hyper-arid desert environments in the Atacama and the Antarctic Dry Valleys and implications for rock weathering

NASA Astrophysics Data System (ADS)

McKay, Christopher P.; Molaro, Jamie L.; Marinova, Margarita M.

2009-09-01

In desert environments with low water and salt contents, rapid thermal variations may be an important source of rock weathering. We have obtained temperature measurements of the surface of rocks in hyper-arid hot and cold desert environments at a rate of 1/s over several days. The values of temperature change over 1-second intervals were similar in hot and cold deserts despite a 30 °C difference in absolute rock surface temperature. The average percentage of the time dT/dt > 2 °C/min was ~ 8 ± 3%, > 4 °C/min was 1 ± 0.9%, and > 8 °C/min was 0.02 ± 0.03%. The maximum change over a 1-second interval was ~ 10 °C/min. When sampled to simulate data taken over intervals longer than 1 s, we found a reduction in time spent above the 2 °C/min temperature gradient threshold. For 1-minute samples, the time spent above any given threshold was about two orders of magnitude lower than the corresponding value for 1-second sampling. We suggest that a rough measure of efficacy of weathering as a function of frequency is the product of the percentage of time spent above a given threshold value multiplied by the damping depth for the corresponding frequency. This product has a broad maximum for periods between 3 and 10 s.

Graphite Black shale of Vendas de Ceira, Coimbra, Portugal

NASA Astrophysics Data System (ADS)

Quinta-Ferreira, Mário; Silva, Daniela; Coelho, Nuno; Gomes, Ruben; Santos, Ana; Piedade, Aldina

2017-04-01

The graphite black shale of Vendas de Ceira located in south of Coimbra (Portugal), caused serious instability problems in recent road excavation slopes. The problems increased with the rain, transforming shales into a dark mud that acquires a metallic hue when dried. The black shales are attributed to the Devonian or eventually, to the Silurian. At the base of the slope is observed graphite black shale and on the topbrown schist. Samples were collected during the slope excavation works. Undisturbed and less altered materials were selected. Further, sampling was made difficult as the graphite shale was covered by a thick layer of reinforced concrete, which was used to stabilize the excavated surfaces. The mineralogy is mainly constituted by quartz, muscovite, ilite, ilmenite and feldspar without the presence of expansive minerals. The organic matter content is 0.3 to 0.4%. The durability evaluated by the Slake Durability Test varies from very low (Id2 of 6% for sample A) to high (98% for sample C). The grain size distribution of the shale particles, was determined after disaggregation with water, which allowed verifying that sample A has 37% of fines (5% of clay and 32% of silt) and 63% of sand, while sample C has only 14% of fines (2% clay and 12% silt) and 86% sand, showing that the decrease in particle size contributes to reduce durability. The unconfined linear expansion confirms the higher expandability (13.4%) for sample A, reducing to 12.1% for sample B and 10.5% for sample C. Due the shale material degradated with water, mercury porosimetry was used. While the dry weight of the three samples does not change significantly, around 26 kN/m3, the porosity is much higher in sample A with 7.9% of pores, reducing to 1.4% in sample C. The pores size vary between 0.06 to 0.26 microns, does not seem to have any significant influence in the shale behaviour. In order to have a comparison term, a porosity test was carried out on the low weatherable brown shale, which is quite abundant at the site. The main difference to the graphite shale is the high porosity of the brown shale with 14.7% and the low volume weight of 23 kN/m3, evidencing the distinct characteristics of the graphite schists. The maximum strength was evaluated by the Schmidt hammer, as the point load test could not be performed as the rock was very soft. The maximum estimated values on dry samples were 32 MPa for sample A and 85 MPa for sample C. The results show a singular material characterized by significant heterogeneity. It can be concluded that for the graphite schists the smaller particle size and higher porosity make the soft rock extremely weatherable when decompressed and exposed to water, as a result of high capillary tension and reduced cohesion. They also exhibit high expansion and an enormous degradation of the rock presenting a behaviour close to a soil. The graphite black schist is a highly weatherable soft rock, without expansive minerals, with small pores, in which the porosity, low strength and low cohesion allow their rapid degradation when decompressed and exposed to the action of Water.

Geological and geomechanical properties of the carbonate rocks at the eastern Black Sea Region (NE Turkey)

NASA Astrophysics Data System (ADS)

Ersoy, Hakan; Yalçinalp, Bülent; Arslan, Mehmet; Babacan, Ali Erden; Çetiner, Gözde

2016-11-01

Turkey located in the Alpine-Himalayan Mountain Belt has 35% of the natural stone reserves of the world and has good quality marble, limestone, travertine and onyx reserves especially in the western regions of the country. The eastern Black Sea Region with a 1.4 million meters cubes reserve has a little role on the natural stone production in the country. For this reason, this paper deals with investigation on the potential of carbonate stone in the region and determination of the geological and geo-mechanical properties of these rocks in order to provide economic contribution to the national economy. While the study sites are selected among the all carbonate rock sites, the importance as well as the representative of the sites were carefully considered for the region. After representative samples were analyzed for major oxide and trace element compositions to find out petrochemical variations, the experimental program conducted on rock samples for determination of both physical and strength properties of the carbonate rocks. The results of the tests showed that there are significant variations in the geo-mechanical properties of the studied rock groups. The density values vary from 2.48 to 2.70 gr/cm3, water absorption by weight values range from 0.07 to 1.15% and the apparent porosity of the carbonate rocks are between 0.19 and 3.29%. However, the values of the UCS shows variation from 36 to 80 MPa. Tensile and bending strength values range from 3.2 to 7.5 MPa and 6.0-9.2 MPa respectively. Although the onyx samples have the lowest values of apparent porosity and water absorption by weight, these samples do not have the highest values of UCS values owing to occurrence of the micro-cracks. The UCS values of the rock samples were also found after cycling tests However, the limestone samples have less than 5% deterioration after freezing-thawing and wetting-drying tests, but travertine and onyx samples have more than 15% deterioration. Exception of the apparent porosity values of travertine samples, all geo-mechanical properties of the studied carbonate rocks were determined in the acceptance values given by Turkish Standards Institute (TSE) for using as a natural dimension stone. After these investigations, it is anticipated that in the near future the number of quarries and factories will increase and more types of natural stones will be discovered in the eastern Black Sea Region and thus this will provide economic contribution to the economy of the country.

77 FR 66457 - Combined Notice of Filings #2

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-05

..., Casselman Windpower LLC, Colorado Green Holdings LLC, Dillon Wind LLC, Dry Lake Wind Power, LLC, Dry Lake Wind Power II LLC, Elk River Windfarm, LLC, Elm Creek Wind, LLC, Elm Creek Wind II LLC, Farmers City Wind, LLC, Flat Rock Windpower LLC, Flat Rock Windpower II LLC, Flying Cloud Power Partners, LLC...

A simple method of predicting S-wave velocity

USGS Publications Warehouse

Lee, M.W.

2006-01-01

Prediction of shear-wave velocity plays an important role in seismic modeling, amplitude analysis with offset, and other exploration applications. This paper presents a method for predicting S-wave velocity from the P-wave velocity on the basis of the moduli of dry rock. Elastic velocities of water-saturated sediments at low frequencies can be predicted from the moduli of dry rock by using Gassmann's equation; hence, if the moduli of dry rock can be estimated from P-wave velocities, then S-wave velocities easily can be predicted from the moduli. Dry rock bulk modulus can be related to the shear modulus through a compaction constant. The numerical results indicate that the predicted S-wave velocities for consolidated and unconsolidated sediments agree well with measured velocities if differential pressure is greater than approximately 5 MPa. An advantage of this method is that there are no adjustable parameters to be chosen, such as the pore-aspect ratios required in some other methods. The predicted S-wave velocity depends only on the measured P-wave velocity and porosity. ?? 2006 Society of Exploration Geophysicists.

Petroleum systems of the San Joaquin Basin Province -- geochemical characteristics of gas types: Chapter 10 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

USGS Publications Warehouse

Lillis, Paul G.; Warden, Augusta; Claypool, George E.; Magoon, Leslie B.

2008-01-01

The San Joaquin Basin Province is a petroliferous basin filled with predominantly Late Cretaceous to Pliocene-aged sediments, with organic-rich marine rocks of Late Cretaceous, Eocene, and Miocene age providing the source of most of the oil and gas. Previous geochemical studies have focused on the origin of the oil in the province, but the origin of the natural gas has received little attention. To identify and characterize natural gas types in the San Joaquin Basin, 66 gas samples were analyzed and combined with analyses of 15 gas samples from previous studies. For the purpose of this resource assessment, each gas type was assigned to the most likely petroleum system. Three general gas types are identified on the basis of bulk and stable carbon isotopic composition—thermogenic dry (TD), thermogenic wet (TW) and biogenic (B). The thermogenic gas types are further subdivided on the basis of the δ13C values of methane and ethane and nitrogen content into TD-1, TD-2, TD-Mixed, TW-1, TW-2, and TW-Mixed. Gas types TD-1 and TD-Mixed, a mixture of biogenic and TD-1 gases, are produced from gas fields in the northern San Joaquin Basin. Type TD-1 gas most likely originated from the Late Cretaceous to Paleocene Moreno Formation, a gas-prone source rock. The biogenic component of the TD-Mixed gas existed in the trap prior to the influx of thermogenic gas. For the assessment, these gas types were assigned to the Winters- Domengine Total Petroleum System, but subsequent to the assessment were reclassified as part of the Moreno-Nortonville gas system. Dry thermogenic gas produced from oil fields in the southern San Joaquin Basin (TD-2 gas) most likely originated from the oil-prone source rock of Miocene age. These samples have low wetness values due to migration fractionation or biodegradation. The thermogenic wet gas types (TW-1, TW-2, TW-Mixed) are predominantly associated gas produced from oil fields in the southern and central San Joaquin Basin. Type TW-1 gas most likely originates from source rocks within the Eocene Kreyenhagen Formation or the Eocene Tumey formation of Atwill (1935). Type TW-2 gas most likely originates from the Miocene Monterey Formation and equivalents. TW-Mixed gas is likely a mixture of biogenic and wet thermogenic gas (TW-1 or TW-2) derived from source rocks mentioned above. The thermogenic wet gas types are included in the corresponding Eocene or Miocene total petroleum systems. Type B gas is a dry, nonassociated gas produced from the Pliocene San Joaquin Formation in the central and southern San Joaquin Basin. This gas type most likely originated from Pliocene marine source rocks as a product of methanogenesis, and defines the Neogene Nonassociated Gas Total Petroleum System.

Changes in Ultrasonic Velocity from Fluid Substitution, Calculated with Laboratory Methods, Digital Rock Physics, and Biot Theory

NASA Astrophysics Data System (ADS)

Goldfarb, E. J.; Ikeda, K.; Tisato, N.

2017-12-01

Seismic and ultrasonic velocities of rocks are function of several variables including fluid saturation and type. Understanding the effect of each variable on elastic waves can be valuable when using seismic methods for subsurface modeling. Fluid type and saturation are of specific interest to volcanology, water, and hydrocarbon exploration. Laboratory testing is often employed to understand the effects of fluids on elastic waves. However, laboratory testing is expensive and time consuming. It normally requires cutting rare samples into regular shapes. Fluid injection can also destroy specimens as removing the fluid after testing can prove difficult. Another option is theoretical modeling, which can be used to predict the effect of fluids on elastic properties, but it is often inaccurate. Alternatively, digital rock physics (DRP) can be used to investigate the effect of fluid substitution. DRP has the benefit of being non invasive, as it does not require regular sample shapes or fluid injection. Here, we compare the three methods for dry and saturated Berea sandstone to test the reliability of DRP. First, ultrasonic velocities were obtained from laboratory testing. Second, for comparison, we used a purely theoretical approach - i.e., Hashin-Shtrikman and Biot theory - to estimate the wave speeds at dry and wet conditions. Third, we used DRP. The dry sample was scanned with micro Computed Tomography (µCT), and a three dimensional (3D) array was recorded. We employed a segmentation-less method to convert each 3D array value to density, porosity, elastic moduli, and wave speeds. Wave propagation was simulated numerically at similar frequency as the laboratory. To simulate fluid substitution, we numerically substituted air values for water and repeated the simulation. The results from DRP yielded similar velocities to the laboratory, and accurately predicted the velocity change from fluid substitution. Theoretical modeling could not accurately predict velocity, and under-predicted the velocity change from fluid substitution. The mathematical approach proved to be a poor comparison for the laboratory measurement. DRP proved to be effective, and could be used in future with drill cuttings, perhaps to limit the use of expensive cores. DRP could also limit the requirement for physically testing fluid substitution.

Laboratory measurements of P- and S-wave anisotropy in synthetic rocks by 3D printing

NASA Astrophysics Data System (ADS)

Kong, L.; Ostadhassan, M.; Tamimi, N.; Li, C.; Alexeyev, A.

2017-12-01

Synthetic rocks have been widely used to realize the models with controlled factors in rock physics and geomechanics experiments. Additive manufacturing technology, known as 3D printing, is becoming a popular method to produce the synthetic rocks as the advantages of timesaving, economics, and control. In terms of mechanical properties, the duplicability of 3D printed rock towards a natural rock has been studied whereas the seismic anisotropy still remains unknown as being the key factor in conducting rock physics experiments. This study utilized a 3D printer with gypsum as the ink to manufacture a series of synthetic rocks that have the shapes of octagonal prisms, with half of them printed from lateral and another half from the bottom. An ultrasonic investigation system was set up to measure the P- and S- wave velocities at different frequencies while samples were under dry conditions. The results show the impact of layered property on the P- and S- wave velocities. The measurement results were compared with the predicted results of Hudson model, demonstrating that the synthetic rock from 3D printing is a transverse isotropic model. The seismic anisotropy indicates that the availability of using 3D printed rocks to duplicate natural rocks for the purpose of recreating the experiments of rock physics. Future experiments will be performed on the dependence of seismic anisotropy on fracture geometry and density in 3D printed synthetic rocks.

Durability of building stones against artificial salt crystallization

NASA Astrophysics Data System (ADS)

Min, K.; Park, J.; Han, D.

2005-12-01

Salts have been known as the most powerful weathering agents, especially when combined with frost action. Salt crystallization test along with freezing-thawing test and acid immersion test was carried out to assess the durability of building stones against weathering. Granite, limestone, marble and basalt were sampled from different quarries in south Korea for this study. One cycle of artificial salt crystallization test was composed of immersion of cored rock specimens in oversaturated solutions of CaCl2, KCl, NaCl and Na2SO4, respectively for 15 hours and successive drying in an oven of 105°C for 3 hours and cooling at room temperature. Tests were performed up to 30 cycles, and specific gravity and ultrasonic velocity were measured after experiencing every 10 cycles and uniaxial compressive strength was measured only after 30 cycles. During the repeated Na2SO4 salt crystallization, some rock samples were gradually deformed excessively and burst after 20 to 30 cycles of test. The variation patterns of physical properties during the salt crystallization tests are too variable to generalize the effect of salt weathering on physical properties but limestone, marble and basalt samples showed relatively greater change of physical properties than granite samples. The recrystallized salts were well observed in the cracks of rock samples through the scanning electron microscope. In the all salt crystallization tests, apparent specific gravities for all tested samples increased generally but not so significantly due to recrystallization of salts. It can be inferred that filling the pores with salt crystals cause the increase of ultrasonic velocity during the early stage of salt crystallization and then in later stages the repeated cycles of salt crystallization result in development of cracks leading decrease of ultrasonic velocity for some rock samples.

Effect of the specimen length on ultrasonic P-wave velocity in some volcanic rocks and limestones

NASA Astrophysics Data System (ADS)

Karaman, Kadir; Kaya, Ayberk; Kesimal, Ayhan

2015-12-01

Ultrasonic P-wave velocity (UPV) is commonly used in different fields such as civil, mining, geotechnical, and rock engineering. One of the significant parameters which affect the UPV of rock materials is likely to be the length of test cores although it is not mentioned in the literature. In this study, in order to explore the influence of the specimen length on the UPV, rock samples were collected from eight different locations in Turkey. The NX-sized core specimens having different length of 50, 75, 100, 125, and 150 mm were prepared. Before the analyses, rocks were divided into two groups in terms of their geological origins such as volcanic and chemical sedimentary (limestone) rocks. The UPV tests were carried out under dry and saturated conditions for each 200 core specimens. By evaluating the test results, it was shown that the length of the specimens significantly affects the UPV values. Based on the regression analyses, a method was developed to determine the threshold specimen length of studied rocks. Fluctuations in UPVdry and UPVsat values were generally observed for cores smaller than the threshold specimen length. In this study, the threshold specimen length was determined as 79 mm for volcanic rocks and 109 mm for limestones.

Salt Weathering on Mars

NASA Astrophysics Data System (ADS)

Jagoutz, E.

2006-12-01

Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974). However, irrespectively of the climatic environment a liquid brine is a necessity for salt induced fragmentation of rocks.M. C. Malin (1974) JGR Vol 79,26 p 3888-3894

Geology and mineral resources of the Mud Springs Ranch Quadrangle, Sweetwater County, Wyoming

USGS Publications Warehouse

Roehler, Henry W.

1979-01-01

The Mud Springs Ranch quadrangle occupies an area of 56 mF (square miles) on the southeast flank of the Rock Springs uplift in southwestern Wyoming. The climate is arid and windy. The landscape is mostly poorly vegetated and consists of north-trending ridges and valleys that are dissected by dry drainages. Sedimentary rocks exposed in the quadrangle are 5,400 ft (feet) thick and are mostly gray sandstone, siltstone, and shale, gray and brown carbonaceous shale, and thin beds of coal. They compose the Blair, Rock Springs, Ericson, Almond, and Lewis Formations of Cretaceous age and the Fort Union Formation of Paleocene age. The structure is mostly homoclinal, having southeast dips of 5?-12? in the northern part of the quadrangle, but minor plunging folds and one small fault are present in the southern part of the quadrangle. Three coal beds in the Fort Union Formation and 15 coal beds in the Almond Formation exceed 2.5 ft in thickness, are under less than 3,000 ft of overburden, and are potentially minable. Geographic stratigraphic, and resource data are present for each bed of minable coal. The total minable coal resources are estimated to be about 283 million short tons. Nine coal and rock samples from outcrops were analyzed to determine their quality and chemical composition. Four dry oil and gas test wells have been drilled within the quadrangle area, but structurally controlled stratigraphic-trap prospects remain untested.

Hydrocarbon source-rock evaluation - Solor Church Formation (middle Proterozoic, Keweenawan Supergroup), southeastern Minnesota

USGS Publications Warehouse

Hatch, J.R.; Morey, G.B.

1984-01-01

In the type section (Lonsdale 65-1 core, Rice County, Minnesota) the Solor Church Formation (Middle Proterozoic, Keweenawan Supergroup) consists primarily of reddish-brown mudstone and siltstone and pale reddish-brown sandstone. The sandstone and siltstone are texturally and mineralogically immature. Hydrocarbon source-rock evaluation of bluish-gray, greenish-gray and medium-dark-gray to grayish-black beds, which primarily occur in the lower 104 m (340 ft) of this core, shows: (1) the rocks have low organic carbon contents (<0.5 percent for 22 of 25 samples); (2) the organic matter is thermally very mature (Tmax = 494°C, sample 19) and is probably near the transition between the wet gas phase of catagenesis and metagenesis (dry gas zone); and (3) the rocks have minimal potential for producing additional hydrocarbons (genetic potential <0.30 mgHC/gm rock). Although no direct evidence exists from which to determine maximum depths of burial, the observed thermal maturity of the organic matter requires significantly greater depths of burial and(or) higher geothermal gradients. It is likely, at least on the St. Croix horst, that thermal alteration of the organic matter in the Solor Church took place relatively early, and that any hydrocarbons generated during this early thermal alteration were probably lost prior to deposition of the overlying Fond du Lac Formation (Middle Proterozoic, Keweenawan Supergroup).

Hydrocarbon source rock evaluation: Solor Church Formation. (Middle Proterozoic, Keweenawan Supergroup) southeastern Minnesota

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

Hatch, J.R.; Morey, G.B.

In the type section (Lonsdale 65-1 core, Rice County, Minnesota) the Solar Church Formation (Middle Proterozoic, Keweenawan Supergroup) consists primarily of reddish-brown mudstone and siltstone and pale reddish-brown sandstone. The sandstone and siltstone are texturally and mineralogically immature. Hydrocarbon source-rock evaluation of bluish-gray, greenish-gray and medium-dark-gray to grayish-black beds, which primarily occur in the lower 104 m (340 ft) of this core, shows: (1) the rocks have low organic carbon contents (<0.5% for 22 of 25 samples); (2) the organic matter is thermally very mature (T/sub max/ = 494/sup 0/C, sample 19) and is probably near the transition between themore » wet gas phase of catagenesis and metagenesis (dry gas zone); and (3) the rocks have minimal potential for producing additional hydrocarbons (genetic potential <0.30 mgHC/gm rock). Although no direct evidence exists from which to determine maximum depths of burial, the observed thermal maturity of the organic matter requires significantly greater depths of burial and(or) higher geothermal gradients. It is likely, at least on the St. Croix horst, that thermal alteration of the organic matter in the Solor Church took place relatively early, and that any hydrocarbons generated during this early thermal alteration were probably lost prior to deposition of the overlying Fond du Lac Formation (Middle Proterozoic, Keweenawan Supergroup). 5 figs., 2 tabs.« less

Environmental Impact of the Helen, Research, and Chicago Mercury Mines on Water, Sediment, and Biota in the Upper Dry Creek Watershed, Lake County, California

USGS Publications Warehouse

Rytuba, James J.; Hothem, Roger L.; May, Jason T.; Kim, Christopher S.; Lawler, David; Goldstein, Daniel; Brussee, Brianne E.

2009-01-01

The Helen, Research, and Chicago mercury (Hg) deposits are among the youngest Hg deposits in the Coast Range Hg mineral belt and are located in the southwestern part of the Clear Lake volcanic field in Lake County, California. The mine workings and tailings are located in the headwaters of Dry Creek. The Helen Hg mine is the largest mine in the watershed having produced about 7,600 flasks of Hg. The Chicago and Research Hg mines produced only a small amount of Hg, less than 30 flasks. Waste rock and tailings have eroded from the mines, and mine drainage from the Helen and Research mines contributes Hg-enriched mine wastes to the headwaters of Dry Creek and contaminate the creek further downstream. The mines are located on federal land managed by the U.S. Bureau of Land Management (USBLM). The USBLM requested that the U.S. Geological Survey (USGS) measure and characterize Hg and geochemical constituents in tailings, sediment, water, and biota at the Helen, Research, and Chicago mines and in Dry Creek. This report is made in response to the USBLM request to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA - Removal Site Investigation (RSI). The RSI applies to removal of Hg-contaminated mine waste from the Helen, Research, and Chicago mines as a means of reducing Hg transport to Dry Creek. This report summarizes data obtained from field sampling of mine tailings, waste rock, sediment, and water at the Helen, Research, and Chicago mines on April 19, 2001, during a storm event. Further sampling of water, sediment, and biota at the Helen mine area and the upper part of Dry Creek was completed on July 15, 2003, during low-flow conditions. Our results permit a preliminary assessment of the mining sources of Hg and associated chemical constituents that could elevate levels of monomethyl Hg (MMeHg) in the water, sediment, and biota that are impacted by historic mining.

The use of the durometer to measure rock hardness in geomorphology. Advantages and limitations.

NASA Astrophysics Data System (ADS)

Feal-Pérez, Alejandra; Blanco-Chao, Ramón; Valcarcel-Díaz, Marcos; Combes, Martín. A.

2010-05-01

The durometer is a hardness tester developed to measure hardness of metallic materials that has been recently introduced to measure rock hardness in weathering studies. Aoki & Matsukura (2007) highlight some advantages of the durometer compared with the Schmidt Rock Test Hammer: the smaller plunge allows measurements in small surfaces such as taffoni or rock carvings, the wider measurement range and the lower impact energy. This last makes it a non destructive method that can be used on relatively soft rocks. In this work the durometer Equotip (©) has been tested in different environments in the field and in the laboratory to explore its applicability and limitations. We applied the device on small rock samples of granite and limestone and a T-test showed that smaller sample size gave smaller hardness values (p < 0.01). Testing the effects of water content, there were no statistically significant differences between water saturated and dry samples. The influence of rock surface roughness was evaluated applying the durometer in ancient rock carvings in medium to coarse grain granites. We compared the values obtained inside and outside the grooves of the carvings using two different support rings, one flat and one concave. The flat ring was not able to reach the bottom of the groove, meanwhile the concave ring adjusts fairly well given its semi spherical section. A t-test confirmed the difference (p < 0.01) between lower rebound values obtained in the grooves using the flat ring and the higher and less scattered values obtained when the concave ring is used. As a very sensitive device, there are some problems in the use related with rock roughness and rock grain size. In weathered medium to coarse grained rocks, with very irregular surfaces, is not easy to get a good contact between the plunge and the rock surface. A poor contact caused by surface roughness causes the scattering and lowering of rebound values. On the contrary, in homogeneous fine grained rocks and in uniform rock surfaces the device gave very good results. The data obtained in glacial, nival and rock coastal environments showed the potential of the device in the identification of changes in rock hardness. We were able to asses the changes in the weathering degree of glacial striations and marked differences in the rock surfaces subjected or not to abrasion. A. Feal-Pérez is supported by the grant AP2006-03854 (Spanish Ministry of Education)

How microfracture roughness can be used to distinguish between exhumed cracks and in-situ flow paths in shales

NASA Astrophysics Data System (ADS)

Pluymakers, Anne; Kobchenko, Maya; Renard, François

2017-01-01

Flow through fractures in shales is of importance to many geoengineering purposes. Shales are not only caprocks to hydrocarbon reservoirs and nuclear waste or CO2 storage sites, but also potential source and reservoir rocks for hydrocarbons. The presence of microfractures in shales controls their permeability and transport properties. Using X-ray micro-tomography and white light interferometry we scanned borehole samples obtained from 4 km depth in the Pomeranian shales in Poland. These samples contain open exhumation/drying cracks as well as intact vein-rock interfaces plus one striated slip surface. At micron resolution and above tensile drying cracks exhibit a power-law roughness with a scaling exponent, called the Hurst exponent H, of 0.3. At sub-micron resolution we capture the properties of the clay interface only, with H = 0.6. In contrast, the in-situ formed veins and slip surface exhibit H = 0.4-0.5, which is deemed representative for in-situ fractures. These results are discussed in relation to the shale microstructure and linear elastic fracture mechanics theory. The data imply that the Hurst roughness exponent can be used as a microstructural criterion to distinguish between exhumation and in-situ fractures, providing a step forward towards the characterization of potential flow paths at depth in shales.

On thermal properties of hard rocks as a host environment of an underground thermal energy storage

NASA Astrophysics Data System (ADS)

Novakova, L.; Hladky, R.; Broz, M.; Novak, P.; Lachman, V.; Sosna, K.; Zaruba, J.; Metelkova, Z.; Najser, J.

2013-12-01

With increasing focus on environmentally friendly technologies waste heat recycling became an important issue. Under certain circumstances subsurface environment could be utilized to accommodate relatively large quantity of heat. Industrial waste heat produced during warm months can be stored in an underground thermal energy storage (UTES) and used when needed. It is however a complex task to set up a sustainable UTES for industrial scale. Number of parameters has to be studied and evaluated by means of thermohydromechanical and chemical coupling (THMC) before any UTES construction. Thermal characteristics of various rocks and its stability under thermal loading are amongst the most essential. In the Czech Republic study two complementary projects THMC processes during an UTES operation. The RESEN project (www.resen.cz) employs laboratory tests and experiments to characterise thermal properties of hard rocks in the Bohemian Massif. Aim of the project is to point out the most suitable rock environment in the Bohemian Massif for moderate to ultra-high temperature UTES construction (Sanyal, 2005). The VITA project (www.geology.cz/mokrsko) studies THM coupling in non-electrical temperature UTES using long term in-situ experiment. In both projects thermal properties of rocks were studied. Thermal conductivity and capacity were measured on rock samples. In addition an influence of increasing temperature and moisture content was considered. Ten hard rocks were investigated. The set included two sandstones, two ignibrites, a melaphyr, a syenite, two granites, a gneiss and a serpentinite. For each rock there were measured thermal conductivity and capacity of at least 54 dried samples. Subsequently, the samples were heated up to 380°C in 8 hours and left to cool down. Thermal characteristics were measured during the heating period and after the sample reached room temperature. Heating and cooling cycle was repeated 7 to 10 times to evaluate possible UTES-like degradation of the studied rocks. The studies revealed thermal loading caused rapid decrease of thermal conductivity of a rock. The decrease of up to 30.6% was observed in sandstones. Reduction up to 16% was found in the granite, 12.3% in the syenite, 12.1% in the gneiss, 10.1% in the serpentinite, 8.1% in the melaphyr and 5.9 - 6.5% in ignimbites. Thermal loading initiated insignificant decrement of the thermal capacity. The capacity loss was usually less than 2%. Increasing content of water caused increase in the measured thermal characteristics. Saturated melaphyr showed 29% higher conductivity and 17.8% higher capacity comparing to the dried one. In the ignibrites there was found growth up to 23.5% in the thermal conductivity and 14.9% in the capacity, 12.1-17.6% and 4.5-5.9% in granites, 9.1% and 11.1% in the serpetinite, 7.9% and 7.9% in the gneiss and 1.2% and 3.4% in the syenite. This work was funded by the Technology Agency of the CR (TA01020348) and Ministry of Industry and trade of the CR (FR-TI3/325). Reference Sanyal, S.K., 2005. Classification of geothermal systems - a possible scheme, Proceedings, 30th Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, p. 85-88.

Geochemical prospecting for copper and nickel in the Wulgai and Tor Tangi areas southeast of Hindubagh, Quetta Division, Pakistan

USGS Publications Warehouse

Stanin, S. Anthony; Wahid, M.A.; Khan, Shamsher

1975-01-01

Showings of magnetite, copper, and possible nickel mineralization in the Hindubagh chromite mining district are near Wulgai and Tor Tangi. Several hundred samples of clastic material from dry streambeds in these areas were sieved for the minus-80-mesh fraction and analyzed for copper using 2, 2'-biquinoline and for nickel using alpha-furildioxime. The copper threshold is 75 ppm, and the nickel threshold is 400 ppm. A geochemical map has been prepared that shows nine areas of anomalously high copper and six areas of high nickel. The nickel anomalies may represent secondary dispersion patterns derived from the erosion of nickeliferous ultramafic rocks of the Hindubagh intrusive complex. Copper showings in and near four of the anomalous copper areas indicate that detailed geological investigation and detailed geochemical sampling of rocks, soil, and unconsolidated clastic material are required to determine the source of the anomalies.

Environmental impact on construction limestone at humid regions with an emphasis on salt weathering, Al-hambra islamic archaeological site, Granada City, Spain: case study

NASA Astrophysics Data System (ADS)

Kamh, G. M. E.

2007-08-01

Al-hambra is an immense and valuable archaeological site in Spain built on Sabika hill with red brick and natural sandy limestone. It exhibits weathering features indicating salt weathering process. The main aim of this study is to examine weathering processes and intensity acting on Al-hambra. Rock petrography and mineralogical composition have been examined using thin sections, scanning electron microscope, X-ray diffraction and X-ray fluorescence; limits of rock’s physical parameters using ultrasonic waves and mercury porosimeter; rock salt content through hydrochemical analysis. Salts attacking this structure are mainly from wet deposition of air pollutants on the long term chemical alteration of rock’s carbonate content to its equivalent salts. The salts’ concentration limit within the examined rock samples is considerably low but it is effective on the long run through hydration of sulphate salts and/or crystallization of chloride salts. Rock texture type and its silica as well as clay content reduces its resistance to internal stresses by salts as well as wetting and drying cycles at such humid area. The recession in limits of physical parameters examined for deep seated and weathered limestone samples quantitatively reflects weathering intensity on Al-hambra.

Unexpected mechanical properties of very dry Berea sandstone near 45°C

NASA Astrophysics Data System (ADS)

Miller, R. A.; Darling, T. W.; TenCate, J. A.; Johnson, P. A.

2011-12-01

An understanding of the nonlinear and hysteretic behavior of porous rocks is important for seismic studies and geologic carbon sequestration applications. However, the fundamental processes responsible for such behavior are poorly understood, including interactions involving adsorbed water and bulk carbon dioxide. Water has been shown to affect the nonlinear mechanical properties of porous rocks, both in high humidity conditions and in low pressure conditions where only a monolayer of water is present on rock grain surfaces [1, 2]. To study the impact of small quantities of adsorbed water on the nonlinear behavior of sandstone, we compare nonlinear resonant ultrasound spectroscopy (NRUS) and time-of-flight modulation (TOFM) measurements [3] on a Berea sandstone core before and after removing bulk water from the sample. Water is removed through extended exposure to ultra high vacuum (UHV) conditions. At the sample's driest state, we achieve a partial pressure of water below 10-8 Torr at room temperature. Periodic measurements record acoustic data as the rock is slowly heated from room temperature to 55°C in UHV. Measurements made after several months of exposure to UHV conditions show behavior we have not previously observed. We report an unexpected sharp increase in Q-1 above 45°C, suggesting we have reduced the concentration of water to a low enough level to affect the sample's mechanical properties. Nonlinear effects are still present when the sample is at its driest state below 45°C, in agreement with previous work [4], which indicates water is not the sole contributor to nonlinearity in porous rock. We are also studying the effect of adding carbon dioxide or argon gas to the dry specimen. We present our acoustic data and propose a model for the impact of adsorbed water on the attenuation of porous rock. [We gratefully acknowledge support from the Nevada Terawatt Facility at the University of Nevada, Reno, and from the Geosciences Research Program of the DOE Office of Basic Energy Sciences]. [1] B. R. Tittmann, L. Ahlberg, and J. Curnow, "Internal friction and velocity measurements," Proc. of 7th Lunar Science Conference , pp. 3123-3132, 1997. [2] K. E.-A. Van Den Abeele, J. Carmeliet, P. A. Johnson, and B. Zinszner, "Influence of water saturation on the nonlinear elastic mesoscopic response in Earth materials and the implications to the mechanism of nonlinearity," Journal of Geophysical Research 107, p. 2121, June 2002. [3] "Dynamic Measures of Elastic Nonlinear (Anelastic) Behavior: Dynamic Acousto-Elasticity Testing (DAET)," G. Renaud, P-Y Le Bas, J. A. TenCate, T. J. Ulrich, J. W. Carey, J. Han, T.W. Darling and P. A. Johnson, AGU Fall Meeting, Dec. 2011. [4] "Water and CO2 chemistry influences on the mechanical integrity of rocks," T.W. Darling, P-Y Le Bas, J. W. Carey, P. A. Johnson and R. A. Miller, AGU Fall Meeting, Dec. 2010.

Unusual properties of high-compliance porosity extracted from measurements of pressure-dependent wave velocities in rocks

NASA Astrophysics Data System (ADS)

Zaitsev, Vladimir Y.; Radostin, Andrey V.; Pasternak, Elena; Dyskin, Arcady

2016-04-01

Conventionally the interpretation of wave velocities and their variations under load is conducted assuming that closable cracks have simple planar shapes, like the popular model of penny-shape cracks. For such cracks, the proportion between complementary variations in different elastic parameters of rocks (such as S- and P-wave velocities) is strictly pre-determined, in particular, it is independent of the crack aspect ratio and rather weakly dependent on the Poisson's ratio of the intact rock. Real rocks, however, contain multitude of cracks of different geometry. Faces of such cracks can exhibit complex modes of interaction when closed by external load, which may result in very different ratios between normal- and shear compliances of such defects. In order to describe the reduction of different elastic moduli, we propose a model in which the compliances of crack-like defects are explicitly decoupled and are not predetermined, so that the ratio q between total normal- and shear- compliances imparted to the rock mass (as well as individual values of these compliances) can be estimated from experimental data on reduction of different elastic moduli (e.g., pressure dependences of P- and S-wave velocities). Physically, the so-extracted ratio q can be interpreted as intrinsic property of individual crack-like defects similar to each other, or as a characteristic of proportion between concentrations of pure normal cracks with very large q and pure shear cracks with q→0. The latter case can correspond, e.g., to saturated cracks in which weakly-compressible liquid prevents crack closing under normal loading. It can be shown that for conventional dry planar cracks, the compliance ratio is q ˜2. The developed model applied to the data on wave-velocity variations with external pressure indicates that elastic properties of the real crack-like defects in rocks can differ considerably from the usually assumed ones. Comparison with experimental data on variations P- and S-wave velocities with hydrostatic compression of different dry and saturated rocks (sandstones, Westerly granite and Webatuck dolomite, etc.) shows that our model is accurate in a wide range of pressures with constant (i.e., pressure-independent) values of parameter q. Furthermore, the determined values of the latter are considerably different from those of conventional cracks. In particular, although all saturated samples have values q <1, the simplified approximation q=0 (i.e., the absence of normal compressibility that is often assumed for wet cracks) leads to large errors in the prediction of complementary variations in the shear- and bulk elastic moduli. Among dry sandstones, the majority have q >2 and many sandstones exhibit unusually high q»1 suggesting quite rough and tortoise nature of real cracks in those rocks. We demonstrate that in such cases, the use of the conventional assumption q ˜2 typical of penny-shape cracks leads to striking inconsistency between the predicted and experimentally observed crack-induced complementary variations in different elastic moduli. Furthermore, among samples with q»1, we revealed numerous examples that demonstrate negative Poisson's ratio at low pressures. VYZ and AVR acknowledge the financial support by RFBR grant No 15-05-05143.

Characterization of a penny-shaped reservoir in a hot dry rock

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

Sekine, H.; Mura, T.

1980-07-10

The mechanical stability of a penny-shaped revervoir is characterized by fracture mechanics including thermoelastic effects in connection with research into the extraction of geothermal energy from hot dry rocks. The condition for stability of a reservoir, which is not changing radius by propagating or closing, requires 0m/sub 0/>m/sub asterisk/; and case 3; m/sub 0/=m/sub asterisk/.

Storage capacity in hot dry rock reservoirs

DOEpatents

Brown, D.W.

1997-11-11

A method is described for extracting thermal energy, in a cyclic manner, from geologic strata which may be termed hot dry rock. A reservoir comprised of hot fractured rock is established and water or other liquid is passed through the reservoir. The water is heated by the hot rock, recovered from the reservoir, cooled by extraction of heat by means of heat exchange apparatus on the surface, and then re-injected into the reservoir to be heated again. Water is added to the reservoir by means of an injection well and recovered from the reservoir by means of a production well. Water is continuously provided to the reservoir and continuously withdrawn from the reservoir at two different flow rates, a base rate and a peak rate. Increasing water flow from the base rate to the peak rate is accomplished by rapidly decreasing backpressure at the outlet of the production well in order to meet periodic needs for amounts of thermal energy greater than a baseload amount, such as to generate additional electric power to meet peak demands. The rate of flow of water provided to the hot dry rock reservoir is maintained at a value effective to prevent depletion of the liquid inventory of the reservoir. 4 figs.

Storage capacity in hot dry rock reservoirs

DOEpatents

Brown, Donald W.

1997-01-01

A method of extracting thermal energy, in a cyclic manner, from geologic strata which may be termed hot dry rock. A reservoir comprised of hot fractured rock is established and water or other liquid is passed through the reservoir. The water is heated by the hot rock, recovered from the reservoir, cooled by extraction of heat by means of heat exchange apparatus on the surface, and then re-injected into the reservoir to be heated again. Water is added to the reservoir by means of an injection well and recovered from the reservoir by means of a production well. Water is continuously provided to the reservoir and continuously withdrawn from the reservoir at two different flow rates, a base rate and a peak rate. Increasing water flow from the base rate to the peak rate is accomplished by rapidly decreasing backpressure at the outlet of the production well in order to meet periodic needs for amounts of thermal energy greater than a baseload amount, such as to generate additional electric power to meet peak demands. The rate of flow of water provided to the hot dry rock reservoir is maintained at a value effective to prevent depletion of the liquid

Production of superheated steam from vapor-dominated geothermal reservoirs

USGS Publications Warehouse

Truesdell, A.H.; White, D.E.

1973-01-01

Vapor-dominated geothermal systems such as Larderello, Italy, The Geysers, California, and Matsukawa, Japan yield dry or superheated steam when exploited. Models for these systems are examined along with production data and the thermodynamic properties of water, steam and rock. It is concluded that these systems initially consist of a water and steam filled reservoir, a water-saturated cap rock, and a water or brine-saturated deep reservoir below a water table. Most liquid water in all parts of the system is relatively immobilized in small pores and crevices; steam dominates the large fractures and voids of the reservoir and is the continuous, pressure-controlling phase. With production, the pressure is lowered and the liquid water boils, causing massive transfer of heat from the rock and its eventual drying. Passage of steam through already dried rock produces superheating. After an initial vaporization of liquid water in the reservoir, the decrease in pressure produces increased boiling below the deep water table. With heavy exploitation, boiling extends deeper into hotter rock and the temperature of the steam increases. This model explains most features of the published production behavior of these systems and can be used to guide exploitation policies. ?? 1973.

The dependence of permeability on effective stress from flow tests at hot dry rock reservoirs at Rosemanowes (Cornwall) and Fenton Hill (New Mexico)

USGS Publications Warehouse

Nathenson, M.

1999-01-01

Effective stress is the primary control on permeability and thus on flow and water loss for two-well hot dry rock systems involving injection and production that have been tested to date. Theoretical relations are derived for the flow between an injector and producer, including the dependence of permeability on effective stress. Four relations for permeability as a function of effective stress are used to match field data for the hot dry rock systems at Rosemanowes, Cornwall, and Fenton Hill, New Mexico. The flow and water loss behavior of these systems are well explained by the influence of effective stress on permeability. All four relations for permeability as a function of effective stress are successful in matching the field data, but some have difficulty in determining unique values for elastic and hydrologic parameters.Effective stress is the primary control on permeability and thus on flow and water loss for two-well hot dry rock systems involving injection and production that have been tested to date. Theoretical relations are derived for the flow between an injector and producer, including the dependence of permeability on effective stress. Four relations for permeability as a function of effective stress are used to match field data for the hot dry rock systems at Rosemanowes, Cornwall, and Fenton Hill, New Mexico. The flow and water loss behavior of these systems are well explained by the influence of effective stress on permeability. All four relations for permeability as a function of effective stress are successful in matching the field data, but some have difficulty in determining unique values for elastic and hydrologic parameters.

Effects of Differential Reinforcement, Physical Restraint and Verbal Reprimand on Stereotyped Body-Rocking.

ERIC Educational Resources Information Center

Jena, S. P. K.

1995-01-01

A boy with severe mental retardation was unresponsive to his environment and spent 80% of his day body-rocking. Stereotyped body-rocking was greatly reduced via differential reinforcement of incompatible responding (DRI), physical restraint, and reprimand. (JDD)

Spatial variability of soils in a seasonally dry tropical forest

NASA Astrophysics Data System (ADS)

Pulla, Sandeep; Riotte, Jean; Suresh, Hebbalalu; Dattaraja, Handanakere; Sukumar, Raman

2016-04-01

Soil structures communities of plants and soil organisms in tropical forests. Understanding the controls of soil spatial variability can therefore potentially inform efforts towards forest restoration. We studied the relationship between soils and lithology, topography, vegetation and fire in a seasonally dry tropical forest in southern India. We extensively sampled soil (available nutrients, Al, pH, and moisture), rocks, relief, woody vegetation, and spatial variation in fire burn frequency in a permanent 50-ha plot. Lower elevation soils tended to be less moist and were depleted in several nutrients and clay. The availability of several nutrients was, in turn, linked to whole-rock chemical composition differences since some lithologies were associated with higher elevations, while the others tended to dominate lower elevations. We suggest that local-scale topography in this region has been shaped by the spatial distribution of lithologies, which differ in their susceptibility to weathering. Nitrogen availability was uncorrelated with the presence of trees belonging to Fabaceae, a family associated with N-fixing species. No effect of burning on soil parameters could be discerned at this scale.

Evaluating the oxidation of shale during hydraulic fracturing using SEM-EDS and spectrocolorimetry

NASA Astrophysics Data System (ADS)

Tan, X. Y.; Nakashima, S.

2017-12-01

During hydraulic fracturing (fracking) for shale gas/oil extraction, oxygen is introduced into deep oxygen-poor environments, and Fe2+-bearing minerals in rocks can be oxidized thus leading to the degradation of rock quality. Akita diatomaceous shale is considered to be one of the source rocks for oil and gas fields in northwestern Japan. Outcrops of Akita shale often show presence of jarosite (Fe sulfate: yellow) and/or goethite (Fe hydroxide: brown to orange) as oxidation products of pyrite (FeS2). Several series of oxidation experiments of Akita shale under dry, humid, and wet conditions were conducted at temperatures of around 30 oC and 50oC for 30-40 days. Portable color spectro-colorimeters were used to monitor color changes of the rock surfaces every hour. SEM-EDS, UV-Vis, and Raman spectroscopic analyses were performed on the rock sample surface to examine the chemical and mineralogical compositions of Akita shale before and after the dry, humid, and wet experiments. In SEM-EDS analyses before the humid experiment, Fe and S containing phases show their atomic ratio close to 1:2 indicating that this is pyrite (FeS2). After the experiment, the ratio changed to around 1:1 suggesting a conversion from pyrite (FeS2) to mackinawite-like mineral (FeS). In addition, the formation of Ca sulfate (possibly gypsum: CaSO4.2H2O) and goethite-like Fe hydroxide were identified which were not present initially. Therefore, oxidation pathways of iron sulfide (pyrite: FeS2) via FeS to sulfate is confirmed by our humid experiments around 30oC on Akita shale. These oxidation processes might occur during the fracking of shale within relatively short time periods associated with precipitation of sulfates and hydroxides. Therefore, further studies are needed for their effects on rock properties and gas/oil production.

Growing Pebbles and Conceptual Prisms - Understanding the Source of Student Misconceptions about Rock Formation.

ERIC Educational Resources Information Center

Kusnick, Judi

2002-01-01

Analyzes narrative essays--stories of rock formation--written by pre-service elementary school teachers. Reports startling misconceptions among preservice teachers on pebbles that grow, human involvement in rock formation, and sedimentary rocks forming as puddles as dry up, even though these students had completed a college level course on Earth…

Low to Extremely Low Water Abundances Measured in Nominally Anhydrous Minerals in Mafic to Granitic Apollo Rock Clasts

NASA Technical Reports Server (NTRS)

Simon, J. I.; Christoffersen, R.; Wang, J.; Alexander, C. M. O'D.; Mills, R. D.; Hauri, E. H.

2017-01-01

Lunar sample-based volatile studies have focused on assessing the inventory and distribution of water in the Moon. Some have focused on the relatively young mare basalts and pyroclastic glasses, which result from partial melting of the relatively young lunar mantle. Less certain is the water inventory for the oldest materials available, which have the greater potential to record the earliest history of volatiles in the Moon (and thus provide evidence for the "wet" vs. "dry" accretion hypotheses of the Earth-Moon system. Studies of volatiles in ancient lunar rocks have largely focused on apatite. One recent FTIR (Fourier Transform Infrared Radiometer) study of plagioclase reported a relatively "wet" (approximately 320 parts per million) magma for primordial ferroan anorthosites (FANs). Another, a NanoSIMS study of alkali feldspar, reported a "wet" (approximately 1 weight percentage) felsic magma, but due to the differentiation processes required for silicic magmatism in the lunar crust, predicted an essentially "dry" (less than 100 parts per million) bulk Moon. Thus, despite evidence that appears to complicate the early "dry" Moon paradigm, there is no apparent unanimity among the measurements, even those on apatite. This disparity is clearly seen by the order of magnitude different water estimates for lunar "alkali-rich suite rocks" (Fig. 1). Some of the apparent differences may be explained by recent improvements in the apatite-based water estimates that better account for relative compatibilities of OH-, Cl, and F. In the present work, we seek to expand our understanding of the volatile abundances in early formed lunar magmas, their source reservoirs, and to address the potential role that felsic magmas play on the lunar hydrogen budget over time by employing NanoSIMS analysis of nominally anhydrous minerals.

Petrography and geochemistry of precambrian rocks from GT-2 and EE-1

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

Laughlin, A.W.; Eddy, A.

1977-08-01

During the drilling of GT-2 and EE-1, 27 cores totaling about 35 m were collected from the Precambrian section. Samples of each different lithology in each core were taken for petrographic and whole-rock major- and trace-element analyses. Whole-rock analyses are now completed on 37 samples. From these data four major Precambrian units were identified at the Fenton Hill site. Geophysical logs and cuttings were used to extrapolate between cores. The most abundant rock type is an extremely variable gneissic unit comprising about 75% of the rock penetrated. This rock is strongly foliated and may range compositionally from syenogranitic to tonaliticmore » over a few centimeters. The bulk of the unit falls within the monzogranite field. Interlayered with the gneiss is a ferrohastingsite-biotite schist which compositionally resembles a basaltic andesite. A fault contact between the schist and gneiss was observed in one core. Intrusive into this metamorphic complex are two igneous rocks. A leucocratic monzogranite occurs as at least two 15-m-thick dikes, and a biotite-granodiorite body was intercepted by 338 m of drill hole. Both rocks are unfoliated and equigranular. The biotite granodiorite is very homogeneous and is characterized by high modal contents of biotite and sphene and by high K/sub 2/O, TiO/sub 2/, and P/sub 2/O/sub 5/ contents. Although all of the cores examined show fractures, most of these are tightly sealed or healed. Calcite is the most abundant fracture filling mineral, but epidote, quartz, chlorite, clays or sulfides have also been observed. The degree of alteration of the essential minerals normally increases as these fractures are approached. The homogeneity of the biotite granodiorite at the bottom of GT-2 and the high degree of fracture filling ensure an ideal setting for the Hot Dry Rock Experiment.« less

Mechanical Weakening during Fluid Injection in Critically Stressed Sandstones with Acoustic Monitoring

NASA Astrophysics Data System (ADS)

David, C.; Dautriat, J. D.; Sarout, J.; Macault, R.; Bertauld, D.

2014-12-01

Water weakening is a well-known phenomenon which can lead to subsidence during the production of hydrocarbon reservoirs. The example of the Ekofisk oil field in the North Sea has been well documented for years. In order to assess water weakening effects in reservoir rocks, previous studies have focused on changes in the failure envelopes derived from mechanical tests conducted on rocks saturated either with water or with inert fluids. However, little attention has been paid so far on the mechanical behaviour during the fluid injection stage, like in enhanced oil recovery operations. We studied the effect of fluid injection on the mechanical behaviour of Sherwood sandstone, a weakly-consolidated sandstone sampled at Ladram Bay in UK. In order to highlight possible weakening effects, water and inert oil have been injected into critically-loaded samples to assess their effect on strength and elastic properties and to derive the acoustic signature of the saturation front for each fluid. The specimens were instrumented with 16 ultrasonic P-wave transducers for both passive and active acoustic monitoring during fluid injection and loading. After conducting standard triaxial tests on three samples saturated with air, water and oil respectively, mechanical creep tests were conducted on dry samples loaded at 80% of the compressive strength of the dry rock. While these conditions are kept constant, a fluid is injected at the bottom end of the sample with a low back pressure (0.5 MPa) to minimize effective stress variations during injection. Both water and oil were used as the injected pore fluid in two experiments. As soon as the fluids start to flow into the samples, creep is taking place with a much higher strain rate for water injection compared to oil injection. A transition from secondary creep to tertiary creep is observed in the water injection test whereas in the oil injection test no significant creep acceleration is observed after one pore volume of oil was injected. The most remarkable difference is that water injection induces mechanical instability and failure, whereas oil injection does not. This was confirmed by the analysis of acoustic emissions activity and post-mortem sample imaging using CT scan. Contrasting evolutions of the P wave velocity during the fluid front propagation were also observed in both experiments.

Surface friction of rock in terrestrial and simulated lunar environments

NASA Technical Reports Server (NTRS)

Roepke, W. W.; Peng, S. S.

1975-01-01

The conventional probe-on-the rotating-disk concept was used to determine the surface friction in mineral probe/specimen interfaces. Nine rocks or minerals and two stainless steels were tested in both new (NT) and same track (ST) tests under three different pressure environments-atmospheric, UHV, and dry nitrogen. Each environment was further subdivided into two testing conditions, that is, ambient and elevated (135 C) temperatures. In NT tests, friction was the lowest in an atmospheric pressure condition for all rock types and increased to the largest in UHV ambient condition except for pyroxene and stainless steel. Friction values measured in dry nitrogen ambient condition lie between the two extremes. Heating tends to increase friction in atmospheric and dry nitrogen environment but decreases in UHV environment with the exception of stainless steel, basalt, and pyroxene. In ST tests, friction was the lowest in the first run and increased in subsequent runs except for stainless steel where the reverse was true. The increases leveled off after a few runs ranging from the second to the seventh depending on rock types.

Preliminary view of geotechnical properties of soft rocks of Semanggol formation at Pokok Sena, Kedah

NASA Astrophysics Data System (ADS)

Ahmad, N. R.; Jamin, N. H.

2018-04-01

The research was inspired by series of geological studies on Semanggol formation found exposed at North Perak, South Kedah and North Kedah. The chert unit comprised interbedded chert-shale rocks are the main lithologies sampled in a small-scale outcrop of Pokok Sena area. Black shale materials were also observed associated with these sedimentary rocks. The well-known characteristics of shale that may swell when absorb water and leave shrinkage when dried make the formation weaker when load is applied on it. The presence of organic materials may worsen the condition apart from the other factors such as the history of geological processes and depositional environment. Thus, this research is important to find the preliminary relations of the geotechnical properties of soft rocks and the geological reasoning behind it. Series of basic soil tests and 1-D compression tests were carried out to obtain the soil parameters. The results obtained gave some preliminary insight to mechanical behaviour of these two samples. The black shale and weathered interbedded chert-shale were classified as sandy-clayey-SILT and clayey-silty-SAND respectively. The range of specific gravity of black shale and interbedded chert/shale 2.3 – 2.6 and fall in the common range of shale and chert specific gravity value. In terms of degree of plasticity, the interbedded chert/shale samples exhibit higher plastic degree compared to the black shale samples. Results from oedometer tests showed that black shale samples had higher overburden pressure (Pc) throughout its lifetime compare to weathered interbedded chert-shale, however the compression index (Cc) of black shale were 0.15 – 0.185 which was higher than that found in interbedded chert-shale. The geotechnical properties of these two samples were explained in correlation with their provenance and their history of geological processes involved which predominantly dictated the mechanical behaviour of these two samples.

Relationships between data from Rock-Eval pyrolysis and proximate, ultimate, petrographic, and physical analyses of 142 diverse U.S. coal samples

USGS Publications Warehouse

Bostick, N.H.; Daws, T.A.

1994-01-01

Basic research on coal and oil shale led to automated pyrolysis analysis of petroleum source rocks; most widely used is the Rock-Eval equipment. In order to interpret Rock-Eval analyses in relation to traditional coal data, we analyzed 142 commercial coals with diverse rank, age, maceral and sulfur contents, for most regions of the United States. We compared the Rock-Eval data with traditional industrial coal data, including volatile matter, calorific value, hydrogen and oxygen content, free swelling index, and vitrinite reflectance. We found: (1) there is a close relationship between Tmax and vitrinite reflectance in the ranges 420-590??C Tmax and 0.4-3%Romax of most coals. (2) A close relationship between Tmax and volatile matter (%VM) extends through the entire sample range, including low-rank samples with 35-70% VM, a range where %VM is not considered to be a useful rank parameter. (3) TOC of medium- and high-rank coals is seriously under-measured by Rock-Eval; TOC of low-rank coals (less than 0.8%Romax) is close to "dry basis" carbon from ultimate analysis. (4) The direct relationships between oxygen index (OI) and %O and between hydrogen index (HI) and %H are clear, though only broadly defined. However, there is virtually no band of concentrated data points on the HI versus OI pseudo-Van Krevelen diagram comparable to the "development line" on the H/C versus O/C diagram. (5) There are systematic relationships between Rock-Eval and industrial coal parameters such as calorific value and FSI, but much standardization would be needed before Rock-Eval could find a place in the coal industry. Tests with blends of coal and quartz sand and with various loads of coal alone showed that the amount of organic matter in the Rock-Eval load greatly influences results. Total load in the crucible, if largely inert, plays a small role, however. Increasing absolute or relative coal content causes under-evaluation of Rock-Eval TOC and over-rating of hydrogen. Blends of several coals yielded hydrogen and oxygen indexes related proportionally to the properties of the individual coals, but Tmax is not raised by addition of high-rank coal until over 40% is added. ?? 1994.

Collecting Ground Samples for Balloon-Borne Instruments

NASA Technical Reports Server (NTRS)

Jones, Jack; Zimmerman, Wayne; Wu, Jiunn Jenq

2009-01-01

A proposed system in a gondola containing scientific instruments suspended by a balloon over the surface of the Saturn moon Titan would quickly acquire samples of rock or ice from the ground below. Prototypes of a sample-collecting device that would be a major part of the system have been tested under cryogenic and non-cryogenic conditions on Earth. Systems like this one could also be used in non-cryogenic environments on Earth to collect samples of rock, soil, ice, mud, or other ground material from such inaccessible or hazardous locations as sites of suspected chemical spills or biological contamination. The sample-collecting device would be a harpoonlike device that would be connected to the balloon-borne gondola by a tether long enough to reach the ground. The device would be dropped from the gondola to acquire a sample, then would be reeled back up to the gondola, where the sample would be analyzed by the onboard instruments. Each prototype of the sample-collecting device has a sharp front (lower) end, a hollow core for retaining a sample, a spring for holding the sample in the hollow core, and a rear (upper) annular cavity for retaining liquid sample material. Aerodynamic fins at the rear help to keep the front end pointed downward. In tests, these prototype devices were dropped from various heights and used to gather samples of dry sand, moist sand, cryogenic water ice, and warmer water ice.

Possible Mud Cracks Preserved in Martian Rock

NASA Image and Video Library

2017-01-17

The network of cracks in this Martian rock slab called "Old Soaker" may have formed from the drying of a mud layer more than 3 billion years ago. The view spans about 4 feet (1.2 meters) left-to-right and combines three images taken by the Mars Hand Lens Imager (MAHLI) camera on the arm of NASA's Curiosity Mars rover. Mud cracks would be evidence of a time when dry intervals interrupted wetter periods that supported lakes in the area. Curiosity has found evidence of ancient lakes in older, lower-lying rock layers and also in younger mudstone that is above Old Soaker. MAHLI was positioned about 3 feet (90 centimeters) above the surface when it took the component images on Dec. 31, 2016, during the 1,566th Martian day, or sol, of Curiosity's work on Mars. This observation was planned as part of assessing a hypothesis that the target preserves evidence of drying mud. The location is within an exposure of Murray formation mudstone on lower Mount Sharp inside Gale Crater. The slab bears a network of four- and five-sided polygons about half an inch to 1 inch (1 to 2 centimeters) across, which matches the pattern commonly formed when a thin layer of mud dries. Some edges of the polygons are ridges of material the same color as the surrounding rock. This could result from a three-step process after cracks form due to drying: Wind-blown sediments accumulate in the open cracks. Later, these sediments and the dried mud become rock under the pressure of multiple younger layers that accumulate on top of them. Most recently, after the overlying layers were eroded away by wind, the vein-filling material resists erosion better than the once-muddy material, so the pattern that began as cracks appears as ridges. Note that some of the cracks contain material much brighter than the surrounding rock. These are mineral veins. Curiosity has found such bright veins of calcium sulfate in many rock layers the rover has investigated. These veins form from circulation of mineral-laden groundwater through underground cracks. Rover-team scientists suggest that a likely scenario for the history of Old Soaker is more than one generation of fracturing: mud cracks first, with sediment accumulating in them, then a later episode of underground fracturing and vein forming. The target rock's name comes from the name of an island off the coast of Maine. The names informally assigned by the rover team to features in the area of lower Mount Sharp that includes this slab are from a list of islands, hills and other sites in or near Maine's Bar Harbor. http://photojournal.jpl.nasa.gov/catalog/PIA21261

Evaluating the Relationships Between NTNU/SINTEF Drillability Indices with Index Properties and Petrographic Data of Hard Igneous Rocks

NASA Astrophysics Data System (ADS)

Aligholi, Saeed; Lashkaripour, Gholam Reza; Ghafoori, Mohammad; Azali, Sadegh Tarigh

2017-11-01

Thorough and realistic performance predictions are among the main requisites for estimating excavation costs and time of the tunneling projects. Also, NTNU/SINTEF rock drillability indices, including the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), and Cutter Life Index™ (CLI), are among the most effective indices for determining rock drillability. In this study, brittleness value (S20), Sievers' J-Value (SJ), abrasion value (AV), and Abrasion Value Cutter Steel (AVS) tests are conducted to determine these indices for a wide range of Iranian hard igneous rocks. In addition, relationships between such drillability parameters with petrographic features and index properties of the tested rocks are investigated. The results from multiple regression analysis revealed that the multiple regression models prepared using petrographic features provide a better estimation of drillability compared to those prepared using index properties. Also, it was found that the semiautomatic petrography and multiple regression analyses provide a suitable complement to determine drillability properties of igneous rocks. Based on the results of this study, AV has higher correlations with studied mineralogical indices than AVS. The results imply that, in general, rock surface hardness of hard igneous rocks is very high, and the acidic igneous rocks have a lower strength and density and higher S20 than those of basic rocks. Moreover, DRI is higher, while BWI is lower in acidic igneous rocks, suggesting that drill and blast tunneling is more convenient in these rocks than basic rocks.

Proposed moduli of dry rock and their application to predicting elastic velocities of sandstones

USGS Publications Warehouse

Lee, Myung W.

2005-01-01

Velocities of water-saturated isotropic sandstones under low frequency can be modeled using the Biot-Gassmann theory if the moduli of dry rocks are known. On the basis of effective medium theory by Kuster and Toksoz, bulk and shear moduli of dry sandstone are proposed. These moduli are related to each other through a consolidation parameter and provide a new way to calculate elastic velocities. Because this parameter depends on differential pressure and the degree of consolidation, the proposed moduli can be used to calculate elastic velocities of sedimentary rocks under different in-place conditions by varying the consolidation parameter. This theory predicts that the ratio of P-wave to S-wave velocity (Vp/Vs) of a dry rock decreases as differential pressure increases and porosity decreases. This pattern of behavior is similar to that of water-saturated sedimentary rocks. If microcracks are present in sandstones, the velocity ratio usually increases as differential pressure increases. This implies that this theory is optimal for sandstones having intergranular porosities. Even though the accurate behavior of the consolidation parameter with respect to differential pressure or the degree of consolidation is not known, this theory presents a new way to predict S-wave velocity from P-wave velocity and porosity and to calculate elastic velocities of gas-hydrate-bearing sediments. For given properties of sandstones such as bulk and shear moduli of matrix, only the consolidation parameter affects velocities, and this parameter can be estimated directly from the measurements; thus, the prediction of S-wave velocity is accurate, reflecting in-place conditions.

Determination of trace amounts of tin in geological materials by atomic absorption spectrometry

USGS Publications Warehouse

Welsch, E.P.; Chao, T.T.

1976-01-01

An atomic absorption method is described for the determination of traces of tin in rocks, soils, and stream sediments. A dried mixture of the sample and ammonium iodide is heated to volatilize tin tetraiodide -which is then dissolved in 5 % hydrochloric acid, extracted into TOPO-MIBK, and aspirated into a nitrous oxide-acetylene flame. The limit of determination is 2 p.p.m. tin and the relative standard deviation ranges from 2 to 14 %. Up to 20 % iron and 1000 p.p.m. Cu, Pb, Zn, Mn, Hg, Mo, V, or W in the sample do not interfere. As many as 50 samples can be easily analyzed per man-day. ?? 1976.

The furnace in the basement: Part 1, The early days of the Hot Dry Rock Geothermal Energy Program, 1970--1973

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

Smith, M.C.

1995-09-01

This report presents the descriptions of the background information and formation of the Los Alamos Scientific Laboratory Geothermal Energy Group. It discusses the organizational, financial, political, public-relations,geologic, hydrologic, physical, and mechanical problems encountered by the group during the period 1970--1973. It reports the failures as well as the successes of this essential first stage in the development of hot dry rock geothermal energy systems.

Possible Signs of Ancient Drying in Martian Rock

NASA Image and Video Library

2017-01-17

A grid of small polygons on the Martian rock surface near the right edge of this view may have originated as cracks in drying mud more than 3 billion years ago. Multiple images from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover were combined for this mosaic of a block called "Squid Cove" and its immediate surroundings. The location is within an exposure of Murray formation mudstone on lower Mount Sharp inside Gale Crater. Mastcam's right-eye camera, which has a telephoto lens, took the component images of this view on Dec. 20, 2016, during the 1,555th Martian day, or sol, of Curiosity's work on Mars. The rover drove farther uphill on Gale Crater before the possible mud cracks were detected in the Mastcam images. This possible evidence about the area's ancient environment prompted the rover mission to backtrack for closer inspection of Squid Cove and nearby target rocks. This scene is presented with a color adjustment that approximates white balancing, to resemble how the rocks and sand would appear under daytime lighting conditions on Earth. The polygons are about half an inch to 1 inch (about 1 to 2 centimeters) across. Figure 1 includes a scale bar of 30 centimeters (12 inches). The polygons are outlined by ridges. This could result from a three-step process after cracks form due to drying: Wind-blown sediments accumulate in the open cracks. Later, these sediments and the dried mud become rock under the pressure of multiple younger layers that accumulate on top of them. Most recently, after the overlying layers were eroded away by wind, the vein-filling material resists erosion better than the once-muddy material, so the pattern that began as cracks appears as ridges. Mud cracks would be evidence of a drying interval between wetter periods that supported lakes in the area. Curiosity has found evidence of ancient lakes in older, lower-lying rock layers and also in younger mudstone that is above Squid Cove. http://photojournal.jpl.nasa.gov/catalog/PIA21263

Alteration of immature sedimentary rocks on Earth and Mars. Recording Aqueous and Surface-atmosphere Processes

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

Cannon, Kenneth M.; Mustard, John F.; Salvatore, Mark R.

The rock alteration and rind formation in analog environments like Antarctica may provide clues to rock alteration and therefore paleoclimates on Mars. Clastic sedimentary rocks derived from basaltic sources have been studied in situ by martian rovers and are likely abundant on the surface of Mars. Moreover, how such rock types undergo alteration when exposed to different environmental conditions is poorly understood compared with alteration of intact basaltic flows. Here we characterize alteration in the chemically immature Carapace Sandstone from Antarctica, a terrestrial analog for martian sedimentary rocks. We employ a variety of measurements similar to those used on previousmore » and current Mars missions. Laboratory techniques included bulk chemistry, powder X-ray diffraction (XRD), hyperspectral imaging and X-ray absorption spectroscopy. Through these methods we find that primary basaltic material in the Carapace Sandstone is pervasively altered to hydrated clay minerals and palagonite as a result of water–rock interaction. A thick orange rind is forming in current Antarctic conditions, superimposing this previous aqueous alteration signature. The rind exhibits a higher reflectance at visible-near infrared wavelengths than the rock interior, with an enhanced ferric absorption edge likely due to an increase in Fe 3+ of existing phases or the formation of minor iron (oxy)hydroxides. This alteration sequence in the Carapace Sandstone results from decreased water–rock interaction over time, and weathering in a cold, dry environment, mimicking a similar transition early in martian history. This transition may be recorded in sedimentary rocks on Mars through a similar superimposition mechanism, capturing past climate changes at the hand sample scale. These results also suggest that basalt-derived sediments could have sourced significant volumes of hydrated minerals on early Mars due to their greater permeability compared with intact igneous rocks.« less

Complicated secondary textures in zircon record evolution of the host granitic rocks: Studies from Western Tauern Window and Ötztal-Stubai Crystalline Complex (Eastern Alps, Western Austria)

NASA Astrophysics Data System (ADS)

Kovaleva, Elizaveta; Harlov, Daniel; Klötzli, Urs

2017-07-01

Samples of metamorphosed and deformed granitic rocks were collected from two Alpine complexes with well-constrained metamorphic history: Western Tauern Window and Ötztal-Stubai Crystalline Complex. Zircon grains from these samples were investigated in situ by a combination of scanning electron microscope techniques, cathodoluminescence (CL) imaging and Raman spectroscopy. The aims were: to describe and interpret complicated secondary textures and microstructures in zircon; based on cross-cutting relationships between secondary microstructures, reconstruct the sequence of processes, affecting zircon crystals; link the evolution of zircon with the history of the host rocks. The results indicate that zircon in the sampled granitic rocks forms growth twins and multi-grain aggregates, which are unusual for this mineral. Moreover, various secondary textures have been found in the sampled zircon, often cross-cutting each other in a single crystal. These include: distorted oscillatory CL zoning with inner zones forming inward-penetrating, CL-bright embayments, which are the evidence of dry recrystallization via annealing/lattice recovery; CL mosaicism with no preservation of growth zoning, but abundant nano- and micro-scale pores and mineral inclusions, which are the evidence of recrystallization by coupled dissolution-reprecipitation and/or leaching; embayed zircon boundaries filled with apatite, monazite, epidote and mylonitic matrix, indicating mineral-fluid reactions resulting in zircon dissolution and fragmentation; overgrowth CL-dark rims, which contain nano-pores and point to transport and precipitation of dissolved zircon matter. We conclude that zircon in our meta-granites is sensitive to metamorphism/deformation events, and was reactive with metamorphic fluids. Additionally, we have found evidence of crystal-plastic deformation in the form of low angle boundaries and bent grain tips, which is a result of shearing and ductile deformation of the host rock. We suggest that the observed complicated secondary textures in zircon can be linked to the evolutionary stages of the host rocks such as magmatic crystallization, prograde metamorphism, peak of amphibolite-facies metamorphism, post-peak cooling and exhumation, formation of ductile shear zones and final cooling to 250 °C.

Novel long-chain anteiso-alkanes and anteiso-alkanoic acids in Antarctic rocks colonized by living and fossil cryptoendolithic microorganisms

NASA Technical Reports Server (NTRS)

Matsumoto, G. I.; Friedmann, E. I.; Watanuki, K.; Ocampo-Friedmann, R.

1992-01-01

Saponified extracts of rock samples colonized by cryptoendolithic microbial communities from the McMurdo Dry Valleys of Southern Victoria Land, Antarctica, were separated into hydrocarbon and fatty acid fractions by silica gel column chromatography. Hydrocarbons and methyl esters of fatty acids were analyzed by capillary gas chromatography-mass spectrometry. Unusually, a suite of long-chain anteiso-alkanes (a-C20 to a-C30) and anteiso-alkanoic acids (a-C20 to a-C30) were detected in many samples, together with straight-chain, branched and/or cyclic and acyclic isoprenoid compounds. These novel compounds are probably derived from unidentified heterotrophic bacteria or symbiotic processes in a unique microbial community in the Antarctic cold desert and suggest the occurrence of a special biosynthetic pathway. Long-chain anteiso-alkanes are probably formed through microbial decarboxylation of corresponding anteiso-alkanoic acids. They may serve as new biomarkers in environmental and geochemical studies.

Investigations in space-related molecular biology. [cryo-electron microscopic and diffraction studies on terrestrial and extraterrestrial specimens

NASA Technical Reports Server (NTRS)

Fernandez-Moran, H.; Pritzker, A. N.

1974-01-01

Improved instrumentation and preparation techniques for high resolution, high voltage cryo-electron microscopic and diffraction studies on terrestrial and extraterrestrial specimens are reported. Computer correlated ultrastructural and biochemical work on hydrated and dried cell membranes and related biological systems provided information on membrane organization, ice crystal formation and ordered water, RNA virus linked to cancer, lunar rock samples, and organometallic superconducting compounds. Apollo 11, 12, 14, and 15 specimens were analyzed

Geophysical Signatures to Monitor Fluids and Mineralization for CO2 Sequestration in Basalts

NASA Astrophysics Data System (ADS)

Otheim, L. T.; Adam, L.; Van Wijk, K.; Batzle, M. L.; Mcling, T. L.; Podgorney, R. K.

2011-12-01

Carbon dioxide sequestration in large reservoirs can reduce emissions of this green house gas into the atmosphere. Basalts are promising host rocks due to their volumetric extend, worldwide distribution, and recent observations that CO2-water mixtures react with basalt minerals to precipitate as carbonate minerals, trapping the CO2. The chemical reaction between carbonic acid and minerals rich in calcium, magnesium and iron precipitates carbonates in the pore space. This process would increase the elastic modulus and velocity of the rock. At the same time, the higher compressibility of CO2 over water changes the elastic properties of the rock, decreasing the saturated rock bulk modulus and the P-wave velocity. Reservoirs where the rock properties change as a result of fluid or pressure changes are commonly monitored with seismic methods. Here we present experiments to study the feasibility of monitoring CO2 migration in a reservoir and CO2-rock reactions for a sequestration scenario in basalts. Our goal is to measure the rock's elastic response to mineralization with non-contacting ultrasonic lasers, and the effect of fluid substitution at reservoir conditions at seismic and ultrasonic frequencies. For the fluid substitution experiment we observe changes in the P- and S-wave velocities when saturating the sample with super-critical (sc) CO2, CO2-water mixtures and water alone for different pore and confining pressures. The bulk modulus of the rock is significantly dependent on frequency in the 2~to 106~Hz range, for CO2-water mixtures and pure water saturations. Dry and pure CO2 (sc or gas) do not show a frequency dependence on the modulus. Moreover, the shear wave modulus is not dispersive for either fluid. The frequency dependence of the elastic parameters is related to the attenuation (1/Q) of the rock. We will show the correlation between frequency dependent moduli and attenuation data for the different elastic moduli of the rocks. Three other basalt samples were stored in a pressure chamber with a sc CO2-water solution to study the effect of mineralization on the elastic properties of the rock. The rock elastic properties are recorded with non-contacting ultrasonic lasers at room conditions. After 15 weeks the first post-mineralization scan showed differences in the rock velocities with respect to the pre-mineralization scan. The analysis is done through coda wave interferometry and direct arrivals. The samples were inserted back into the pressure vessel for continuing mineralization and subsequent scans. Finally, we will discuss the applicability of Gassmann's equation and how the combination of mineralization together with CO2-water mixture affects the velocity of waves in basalt rocks.

Hot dry rock and the U.S. geological survey: a question of priorities

USGS Publications Warehouse

Sass, John H.

1996-01-01

The enactment of the Energy Policy Act of 1992 saw the assignment of definite responsibilities relating to hot dry rock (HDR) to the US Geological Survey (USGS). This mandate provided some explicit guidelines and individual tasks in areas in which the USGS already had close ties to the Department of Energy and a number of its national laboratories. This paper discusses various tasks in terms of priorities being conducted by USGS as response to the Act.

Trace elements and radon in groundwater across the United States, 1992-2003

USGS Publications Warehouse

Ayotte, Joseph D.; Gronberg, Jo Ann M.; Apodaca, Lori E.

2011-01-01

Trace-element concentrations in groundwater were evaluated for samples collected between 1992 and 2003 from aquifers across the United States as part of the U.S. Geological Survey National Water-Quality Assessment Program. This study describes the first comprehensive analysis of those data by assessing occurrence (concentrations above analytical reporting levels) and by comparing concentrations to human-health benchmarks (HHBs). Data from 5,183 monitoring and drinking-water wells representing more than 40 principal and other aquifers in humid and dry regions and in various land-use settings were used in the analysis. Trace elements measured include aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), silver (Ag), strontium (Sr), thallium (Tl), uranium (U), vanadium (V), and zinc (Zn). Radon (Rn) gas also was measured and is included in the data analysis. Climate influenced the occurrence and distribution of trace elements in groundwater whereby more trace elements occurred and were found at greater concentrations in wells in drier regions of the United States than in humid regions. In particular, the concentrations of As, Ba, B, Cr, Cu, Mo, Ni, Se, Sr, U, V, and Zn were greater in the drier regions, where processes such as chemical evolution, ion complexation, evaporative concentration, and redox (oxidation-reduction) controls act to varying degrees to mobilize these elements. Al, Co, Fe, Pb, and Mn concentrations in groundwater were greater in humid regions of the United States than in dry regions, partly in response to lower groundwater pH and (or) more frequent anoxic conditions. In groundwater from humid regions, concentrations of Cu, Pb, Rn, and Zn were significantly greater in drinking-water wells than in monitoring wells. Samples from drinking-water wells in dry regions had greater concentrations of As, Ba, Pb, Li, Sr, V, and Zn, than samples from monitoring wells. In humid regions, however, concentrations of most trace elements were greater in monitoring wells than in drinking-water wells; the exceptions were Cu, Pb, Zn, and Rn. Cu, Pb, and Zn are common trace elements in pumps and pipes used in the construction of drinking-water wells, and contamination from these sources may have contributed to their concentrations. Al, Sb, Ba, B, Cr, Co, Fe, Mn, Mo, Ni, Se, Sr, and U concentrations were all greater in monitoring wells than in drinking-water wells in humid regions. Groundwater from wells in agricultural settings had greater concentrations of As, Mo, and U than groundwater from wells in urban settings, possibly owing to greater pH in the agricultural wells. Significantly greater concentrations of B, Cr, Se, Ag, Sr, and V also were found in agricultural wells in dry regions. Groundwater from dry-region urban wells had greater concentrations of Co, Fe, Pb, Li, Mn, and specific conductance than groundwater from agricultural wells. The geologic composition of aquifers and aquifer geochemistry are among the major factors affecting trace-element occurrence. Trace-element concentrations in groundwater were characterized in aquifers from eight major groups based on geologic material, including (1) unconsolidated sand and gravel; (2) glacial unconsolidated sand and gravel; (3) semiconsolidated sand; (4) sandstone; (5) sandstone and carbonate rock; (6) carbonate rock; (7) basaltic and other volcanic rock; and (8) crystalline rock. The majority of groundwater samples and the largest percentages of exceedences of HHBs were in the glacial and nonglacial unconsolidated sand and gravel aquifers; in these aquifers, As, Mn, and U are the most common trace elements exceeding HHBs. Overall, 19 percent of wells (962 of 5,097) exceeded an HHB for at least one trace element. The trace elements with HHBs included in this summary were Sb, As, Ba, Be, B, Cd, Cr,

Heavy metals and organic carbon in sediments from the Tuy River basin, Venezuela.

PubMed

Mogollón, J L; Ramirez, A J; Guillén, R B; Bifano, C

1990-12-01

The Tuy River basin, located in north-central Venezuela with an annual average temperature of 27°C and precipitation of 140 cm, was selected to conduct a geochemical study of bottom sediments, with the object of establishing the natural and human influences in the abundance and distribution of Fe, Mn, Cr, Co, Cu, Ni, Pb, Zn and organic carbon. The basin is lithologically divided into two sub-basins, north and south. The north sub-basin drains a iow-grade metasedimentary terrain with a population density of 800 persons km(-2) and approximateiy 600 industrial sites, while the south sub-basin in underlain by metavolcanic and ultramafic rocks, with a population density of less than 10 persons km(-2).Stream bottom sediment samples (150) were collected during the years of 1979-1986 in 16 unpolluted sites and 13 polluted sites. The sediments were air dried at room temperature and sieved through a 120 stainless steel mesh (125 μm). Samples of grain size smaller than 125 μm were analysed, the heavy metals being determined by atomic absorption spectrometry and the organic carbon (Corg) by dry combustion.The higher concentrations of heavy metals and organic carbon found in the pristine areas were in the south sub-basin, especially in those areas with higher annual precipitation and tropical forest. This indicated that the metavolcanic and ultramafic rocks yield higher concentrations of heavy metals than the metasedimentary rocks. It was also noted that the higher concentrations of Cr and Ni are associated with the ultramafic rocks. The results obtained from the sediment samples collected in the polluted sites showed that the elements Pb, Zn and Corg are enriched up to 4 times as a result of ail the human activities taking place in the basin. Organic carbon is an excellent indicator of domestic wastewater, Pb and Zn are good indicators of the automotive traffic and industrial effluents. The concentrations of each heavy metal did not show any significant correlation with grain size fractions; however, the concentration of organic carbon did show a negative correlation with grain size. The lithological, climatic and vegetation influence in the abundance of heavy metals and organic carbon in stream sediments clearly indicates the necessity of establishing background levels for the area under study when carrying out studies in environmental geochemistry.

The role of pore fluids on deforming volcanic rocks: an experimental study

NASA Astrophysics Data System (ADS)

Fazio, Marco; Benson, Philip; Vinciguerra, Sergio; Meredith, Philip

2015-04-01

Pore fluids play an important role on the process of the deformation of rocks. Not only it affects the mechanical properties and the elastic velocities of the material, but it is also responsible in the generation of a whole kind of seismicity, characterized by lower frequency and longer tail (i.e. Long Period, LP, and Hybrid events) than the Volcano-Tectonic (VT) signals, generated by simple shear. While great progress has been made in understanding VT events, LPs, Hybrid signals and the transition between these types of activity are not fully understood yet. This study, aiming in particular on the transition between VT and Hybrid events, shows the results of triaxial experiments on a volcanic rock, run both in dry and wet conditions, to better understand the role of the pore fluids on the final stage of the deformation tests, when the sample is approaching failure. This is achieved through a servo-controlled triaxial testing machine and a state-of the-art acoustic emissions (AEs) kit, composed by an array of 12 piezoelectric sensors surrounding the sample and by both a "triggered" unit, where the events are recorded only if a certain threshold is reached, and a "continuous" unit, where the data is recorded from the beginning to the end of the acquisition, fundamental when the AEs grow exponentially and the triggered unit cannot store at the same rate. The use of sensors of different dominant frequency allows us to better investigate the events occurring as the sample is approaching failure. In both conditions we observe a decrease of the dominant frequency of the seismic activity, due to two different processes: in dry conditions the coalescence of fractures, eventually leading to the major shear zone, creates relatively low-frequency VT events; the same occurs in wet conditions, but the movement of fluids, eased by the merging of the cracks, generates hybrid events. These two type of seismicity are then distinguished in terms of their source mechanism components, where the low-frequency VTs are characterized by a higher DC component, while hybrid events show a greater CLVD one. These results may have a great impacts in the failure forecasting models, not only in volcanic settings, but wherever the pore fluids play an important role on the stability of the rock mass.

The characteristics of geothermal field of Qiabuqia town in Gonghe basin, northeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Zhang, C.; Shi, Y.; Jiang, G.

2017-12-01

Located in the northeastern margin of Gonghe basin, Qiabuqia town displays the most potential of hot dry rock geothermal resources exploration and development in China so far. Although large quantities of geophysical exploration work have been down since 2013, the study of present geothermal field is almost empty, which is seriously restricting the evaluation and utilization of geothermal resources in Qiabuqia town. This study is to revel the geothermal characteristics of four hot dry rock boreholes (DR4, DR3, GR1 and GR2) though continuous steady temperature logging and thermal conductivity measurements of core samples. The main stratum of study area are Indosinian granitic rocks (below 1400 m) which is overlain by thick Paleogene, Neogene and Quaternary lacustrine strata (0 1400 m). Continuous temperature logs display that the bottom hole temperature of DR3 borehole is up to 180 oC at the depth of 3000 m and it is the first successfully verification of the existence of hot dry rock geothermal resources in China. The temperature gradients of these for boreholes are obtained by the linear least squares regression method and it turns out that the temperature gradient varies from 38 to 45.2 oC • km-1 with an average of 40.4 oC • km-1. Average thermal conductivity of bedrocks ranges from 2.07 to 3.10 W/(m • K) with an mean of 2.52 W/(m • K). Heat flow values are calculated as the product of least-square thermal gradients and corresponding thermal conductivity. By the result of the calculation, the heat flow are 98.9 mW • m-2, 114.7 mW • m-2, 96.2 mW • m-2, 97.8 mW • m-2 for DR4, DR3, GR1 and GR2 borehole, respectively. Compared to the adjacent Qaidam basin, Sichuan basin and Ordos basin, the study area appear to be a thermal abnormal area with high temperature gradient and high heat flow.

Evaluation of Mercury Contamination in Fungi Boletus Species from Latosols, Lateritic Red Earths, and Red and Yellow Earths in the Circum-Pacific Mercuriferous Belt of Southwestern China.

PubMed

Falandysz, Jerzy; Zhang, Ji; Wang, Yuan-Zhong; Saba, Martyna; Krasińska, Grażyna; Wiejak, Anna; Li, Tao

2015-01-01

For the first time, highly elevated levels of mercury (Hg) have been documented for several species of the edible Fungi genus Boletus growing in latosols, lateritic red earths, and red and yellow earths from the Yunnan province of China. Analysis of Hg concentrations in the genus suggests that geogenic Hg is the dominant source of Hg in the fungi, whereas anthropogenic sources accumulate largely in the organic layer of the forest soil horizon. Among the 21 species studied from 32 locations across Yunnan and 2 places in Sichuan Province, the Hg was found at elevated level in all samples from Yunnan but not in the samples from Sichuan, which is located outside the mercuriferous belt. Particularly abundant in Hg were the caps of fruiting bodies of Boletus aereus (up to 13 mg kg-1 dry matter), Boletus bicolor (up to 5.5 mg kg-1 dry matter), Boletus edulis (up to 22 mg kg-1 dry matter), Boletus luridus (up to 11 mg kg-1 dry matter), Boletus magnificus (up to 13 mg kg-1 dry matter), Boletus obscureumbrinus (up to 9.4 mg kg-1 dry matter), Boletus purpureus (up to 16 mg kg-1 dry matter), Boletus sinicus (up to 6.8 mg kg-1 dry matter), Boletus speciosus (up to 4.9mg kg-1 dry matter), Boletus tomentipes (up to 13 mg kg-1 dry matter), and Boletus umbriniporus (up to 4.9 mg kg-1 dry matter). Soil samples of the 0-10 cm topsoil layer from the widely distributed locations had mercury levels ranging between 0.034 to 3.4 mg kg-1 dry matter. In Yunnan, both the soil parent rock and fruiting bodies of Boletus spp. were enriched in Hg, whereas the same species from Sichuan, located outside the mercuriferous belt, had low Hg concentrations, suggesting that the Hg in the Yunnan samples is mainly from geogenic sources rather than anthropogenic sources. However, the contribution of anthropogenically-derived Hg sequestered within soils of Yunnan has not been quantified, so more future research is required. Our results suggest that high rates of consumption of Boletus spp. from Yunnan can deliver relatively high doses of Hg to consumers, but that rates can differ widely because of large variability in mercury concentrations between species and locations.

Evaluation of Mercury Contamination in Fungi Boletus Species from Latosols, Lateritic Red Earths, and Red and Yellow Earths in the Circum-Pacific Mercuriferous Belt of Southwestern China

PubMed Central

Falandysz, Jerzy; Zhang, Ji; Wang, Yuan-Zhong; Saba, Martyna; Krasińska, Grażyna; Wiejak, Anna; Li, Tao

2015-01-01

For the first time, highly elevated levels of mercury (Hg) have been documented for several species of the edible Fungi genus Boletus growing in latosols, lateritic red earths, and red and yellow earths from the Yunnan province of China. Analysis of Hg concentrations in the genus suggests that geogenic Hg is the dominant source of Hg in the fungi, whereas anthropogenic sources accumulate largely in the organic layer of the forest soil horizon. Among the 21 species studied from 32 locations across Yunnan and 2 places in Sichuan Province, the Hg was found at elevated level in all samples from Yunnan but not in the samples from Sichuan, which is located outside the mercuriferous belt. Particularly abundant in Hg were the caps of fruiting bodies of Boletus aereus (up to 13 mg kg-1 dry matter), Boletus bicolor (up to 5.5 mg kg-1 dry matter), Boletus edulis (up to 22 mg kg-1 dry matter), Boletus luridus (up to 11 mg kg-1 dry matter), Boletus magnificus (up to 13 mg kg-1 dry matter), Boletus obscureumbrinus (up to 9.4 mg kg-1 dry matter), Boletus purpureus (up to 16 mg kg-1 dry matter), Boletus sinicus (up to 6.8 mg kg-1 dry matter), Boletus speciosus (up to 4.9mg kg-1 dry matter), Boletus tomentipes (up to 13 mg kg-1 dry matter), and Boletus umbriniporus (up to 4.9 mg kg-1 dry matter). Soil samples of the 0–10 cm topsoil layer from the widely distributed locations had mercury levels ranging between 0.034 to 3.4 mg kg-1 dry matter. In Yunnan, both the soil parent rock and fruiting bodies of Boletus spp. were enriched in Hg, whereas the same species from Sichuan, located outside the mercuriferous belt, had low Hg concentrations, suggesting that the Hg in the Yunnan samples is mainly from geogenic sources rather than anthropogenic sources. However, the contribution of anthropogenically-derived Hg sequestered within soils of Yunnan has not been quantified, so more future research is required. Our results suggest that high rates of consumption of Boletus spp. from Yunnan can deliver relatively high doses of Hg to consumers, but that rates can differ widely because of large variability in mercury concentrations between species and locations. PMID:26606425

Percolation Pore Network Study on the Residue Gas Saturation of Dry Reservoir Rocks

NASA Astrophysics Data System (ADS)

Cheng, T.; Tang, Y. B.; Zou, G. Y.; Jiang, K.; Li, M.

2014-12-01

We tried to model the effect of pore size heterogeneity and pore connectivity on the residue gas saturation for dry gas reservoir rocks. If we consider that snap-off does not exist and only piston displacement takes place in all pores with the same size during imbibition process, in the extreme case, the residue gas saturation will be equal to zero. Thus we can suppose that the residue gas saturation of dry rocks is mainly controlled by the pore size distribution. To verify the assumption, percolation pore networks (i.e., three-dimensional simple cubic (SC) and body-center cubic (BCC)) were used in the study. The connectivity and the pore size distribution in percolation pore network could be changed randomly. The concept of water phase connectivity zw(i.e., water coordination number) and gas phase connectivity zg (i.e., gas coordination number) was introduced here. zw and zg will change during simulation and can be estimated numerically from the results of simulations through gradually saturated networks by water. The Simulation results show that when zg less than or equal to 1.5 during water quasi - static imbibition, the gas will be trapped in rock pores. Network simulation results also shows that the residue gas saturation Srg follows a power law relationship (i.e.,Srg∝σrα, where σr is normalized standard deviation of the pore radius distribution, and exponent α is a function of coordination number). This indicates that the residue gas saturation has no explicit relationship with porosity and permeability as it should have in light of previous study, pore radius distribution is the principal factor in determining the residue gas saturation of dry reservoir rocks.

Computation of dynamic seismic responses to viscous fluid of digitized three-dimensional Berea sandstones with a coupled finite-difference method.

PubMed

Zhang, Yang; Toksöz, M Nafi

2012-08-01

The seismic response of saturated porous rocks is studied numerically using microtomographic images of three-dimensional digitized Berea sandstones. A stress-strain calculation is employed to compute the velocities and attenuations of rock samples whose sizes are much smaller than the seismic wavelength of interest. To compensate for the contributions of small cracks lost in the imaging process to the total velocity and attenuation, a hybrid method is developed to recover the crack distribution, in which the differential effective medium theory, the Kuster-Toksöz model, and a modified squirt-flow model are utilized in a two-step Monte Carlo inversion. In the inversion, the velocities of P- and S-waves measured for the dry and water-saturated cases, and the measured attenuation of P-waves for different fluids are used. By using such a hybrid method, both the velocities of saturated porous rocks and the attenuations are predicted accurately when compared to laboratory data. The hybrid method is a practical way to model numerically the seismic properties of saturated porous rocks until very high resolution digital data are available. Cracks lost in the imaging process are critical for accurately predicting velocities and attenuations of saturated porous rocks.

Dependence of frictional strength on compositional variations of Hayward fault rock gouges

USGS Publications Warehouse

Morrow, Carolyn A.; Moore, Diane E.; Lockner, David A.

2010-01-01

The northern termination of the locked portion of the Hayward Fault near Berkeley, California, is found to coincide with the transition from strong Franciscan metagraywacke to melange on the western side of the fault. Both of these units are juxtaposed with various serpentinite, gabbro and graywacke units to the east, suggesting that the gouges formed within the Hayward Fault zone may vary widely due to the mixing of adjacent rock units and that the mechanical behavior of the fault would be best modeled by determining the frictional properties of mixtures of the principal rock types. To this end, room temperature, water-saturated, triaxial shearing tests were conducted on binary and ternary mixtures of fine-grained gouges prepared from serpentinite and gabbro from the Coast Range Ophiolite, a Great Valley Sequence graywacke, and three different Franciscan Complex metasedimentary rocks. Friction coefficients ranged from 0.36 for the serpentinite to 0.84 for the gabbro, with four of the rock types having coefficients of friction ranging from 0.67-0.84. The friction coefficients of the mixtures can be predicted reliably by a simple weighted average of the end-member dry-weight percentages and strengths for all samples except those containing serpentinite. For the serpentinite mixtures, a linear trend between end-member values slightly overestimates the coefficients of friction in the midcomposition ranges. The range in strength for these rock admixtures suggests that both theoretical and numerical modeling of the fault should attempt to account for variations in rock and gouge properties.

The economical utilization of geothermal energy

NASA Astrophysics Data System (ADS)

Rose, G.

1982-12-01

The geothermal energy which is stored in hot dry rock could be theoretically utilized for the generation of power. The hot-dry-rock procedure can provide a flow of hot water. The considered binary system can transform the obtained thermal energy into electrical energy. The system makes use of a Rankine cycle with a working fluid having a low boiling point. Heat from the hot water is transferred to the working fluid. The present investigation is concerned with the development of a method for the calculation of the entire process. The results obtained with the computational method are to provide a basis for the determination of the operational characteristics. The development method is used for the study of a process based on the use of carbon dioxide as working fluid. The economics of a use of the hot-dry-rock process with the binary system is also investigated. It is found that the considered procedure is not economical. Economical operation requires, in particular, hot water supplied at a much lower cost.

Long-term effects of CO2 on the mechanical behaviour of faults - a study of samples from a natural CO2 analogue (Entrada Sandstone, Utah, USA)

NASA Astrophysics Data System (ADS)

Hangx, S. J. T.; Bakker, E.; Spiers, C. J.

2012-04-01

In an attempt to reduce CO2 emissions, CO2 capture and storage in depleted oil and gas reservoirs is seen as one of the most important mitigation strategies. However, in order to achieve safe storage on geological timescales, it is key to maintain integrity of the caprock and any faults penetrating the seal. One of the largest uncertainties lies in the prediction of the effects of fluid-rock interaction on the mechanical integrity and sealing capacity of the reservoir-seal system in the very long term, i.e. on timescales of the order of 103 or 104 years. As chemical interactions in the rock/CO2/brine system are slow, their long-term effects on rock composition, microstructure, mechanical properties and transport properties cannot be properly reproduced in laboratory experiments. One way of addressing this issue is to conduct experiments on reservoir, caprock and fault rock samples taken from natural CO2 reservoir-seal systems, which can serve as natural analogues for CO2 storage fields. The transport and mechanical properties of these rock samples, which have reacted with CO2 over geological timescales, can then be compared with data obtained for laterally equivalent materials that are unaffected by CO2. The observed changes in rock properties can subsequently be used as input for numerical models aimed at assessing the long-term effects of CO2 on reservoir compaction, caprock damage, fault reactivation and fault permeability. We assessed the mechanical behaviour and transport properties of fault rocks. To this end, we performed triaxial direct shear experiments at room temperature under nominally dry conditions, at normal stresses up to 90 MPa and shear velocities of 0.22 -10.9 μm/s. Simulated fault rocks were prepared by crushing material obtained from surface outcrops of the Entrada Sandstone, one of the CO2-bearing formations from an analogue field under the Colorado Plateau, Utah, USA. Three types of starting material were obtained: 1) red-coloured samples consisting mainly of quartz and feldspar, some minor clay minerals and hematite/goethite grain coatings, 2) yellow-coloured, (so-called) bleached samples additionally containing various amounts of kaolinite, calcite and dolomite, and 3) heavily cemented samples from the surface outcrop of the fault core of the Little Grand Wash Fault, containing a high percentage of carbonates (> 40 wt%). Previous work demonstrates that the bleached samples and the material from the fault were altered as a result of interaction with CO2-rich fluids. Over the experimental range investigated, we measured friction coefficients of 0.55-0.85 for unbleached material and 0.55-0.80 for bleached material, while the fault core material showed higher friction coefficients (0.60-0.95), all showing a minor decrease with decreasing shear velocity and normal stress. Almost all samples showed velocity-strengthening slip behaviour. Overall, the frictional behaviour of Entrada Sandstone does not seem to be strongly influenced by CO2/brine/rock interactions.

Design and development of a dust dispersion chamber to quantify the dispersibility of rock dust.

PubMed

Perera, Inoka E; Sapko, Michael J; Harris, Marcia L; Zlochower, Isaac A; Weiss, Eric S

2016-01-01

Dispersible rock dust must be applied to the surfaces of entries in underground coal mines in order to inert the coal dust entrained or made airborne during an explosion and prevent propagating explosions. 30 CFR. 75.2 states that "… [rock dust particles] when wetted and dried will not cohere to form a cake which will not be dispersed into separate particles by a light blast of air …" However, a proper definition or quantification of "light blast of air" is not provided. The National Institute for Occupational Safety and Health (NIOSH) has, consequently, designed a dust dispersion chamber to conduct quantitative laboratory-scale dispersibility experiments as a screening tool for candidate rock dusts. A reproducible pulse of air is injected into the chamber and across a shallow tray of rock dust. The dust dispersed and carried downwind is monitored. The mass loss of the dust tray and the airborne dust measurements determine the relative dispersibility of the dust with respect to a Reference rock dust. This report describes the design and the methodology to evaluate the relative dispersibility of rock dusts with and without anti-caking agents. Further, the results of this study indicate that the dispersibility of rock dusts varies with particle size, type of anti-caking agent used, and with the untapped bulk density. Untreated rock dusts, when wetted and dried forming a cake that was much less dispersible than the reference rock dust used in supporting the 80% total incombustible content rule.

Dry Sliding Wear Charactristics of Aluminum 6061-T6, Magnesium AZ31 and Rock Dust Composite

NASA Astrophysics Data System (ADS)

Balachandar, R.; Balasundaram, R.; Rajkumar, G.

2018-02-01

In recent years, the use of aluminum composite is gaining popularity in a wide range of applications like automobiles, aerospace and constructions (both interior & exterior) panels etc., due to its high strength, low density characteristics. Various reinforcing materials are used with aluminum 6061-T6 in order to have better mechanical properties. The addition of 0.3% of magnesium AZ31 will increase the ultimate tensile strength by 25 %. The reinforcement of rock dust will decrease the density. Hence, in order to have an advantages of magnesium AZ31 and rock dust, in this work, these two constitutes are varied from 1% to 2% on the base material of Al6061-T6 in stir casting. To evaluate the wear characteristics, Pin on disc is used in these composites. The input parameters are speed, time & load. The output response is wear. To minimize the number of experiments, L9 orthogonal array is used. The test results showed that a composite of 97% of Al (6061-T6), 1% Mg (AZ31) & 2 % of rock dust produced less wear. To find the best value of operating parameter for each sample, ANN-GA is used.

Fracturing of porous rock induced by fluid injection

NASA Astrophysics Data System (ADS)

Stanchits, Sergei; Mayr, Sibylle; Shapiro, Serge; Dresen, Georg

2011-04-01

We monitored acoustic emission (AE) activity and brittle failure initiated by water injection into initially dry critically stressed cylindrical specimens of Flechtingen sandstone of 50 mm diameter and 105-125 mm length. Samples were first loaded in axial direction at 40-50 MPa confining pressure at dry conditions close to peak stress. Subsequently distilled water was injected either at the bottom of specimen or via a central borehole at pore pressures of 5-30 MPa. Water injection into stressed porous sandstone induced a cloud of AE events located close to the migrating water front. Water injection was monitored by periodic ultrasonic velocity measurements across the sample. Propagation of the induced cloud of AE was faster in the direction parallel to bedding than normal to it, indicating permeability anisotropy. Water injection was associated with significant AE activity demonstrating increased contribution of tensile source type. Brittle failure was accompanied by increased contribution of shear and pore collapse source types. At a critical pore pressure, a brittle fault nucleated from a cloud of induced AE events in all samples. Microstructural analysis of fractured samples shows excellent agreement between location of AE hypocenters and macroscopic faults.

Influence of Water Saturation on Thermal Conductivity in Sandstones

NASA Astrophysics Data System (ADS)

Fehr, A.; Jorand, R.; Koch, A.; Clauser, C.

2009-04-01

Information on thermal conductivity of rocks and soils is essential in applied geothermal and hydrocarbon maturation research. In this study, we investigate the dependence of thermal conductivity on the degree of water saturation. Measurements were made on five sandstones from different outcrops in Germany. In a first step, we characterized the samples with respect to mineralogical composition, porosity, and microstructure by nuclear magnetic resonance (NMR) and mercury injection. We measured thermal conductivity with an optical scanner at different levels of water saturation. Finally we present a simple and easy model for the correlation of thermal conductivity and water saturation. Thermal conductivity decreases in the course of the drying of the rock. This behaviour is not linear and depends on the microstructure of the studied rock. We studied different mixing models for three phases: mineral skeleton, water and air. For argillaceous sandstones a modified arithmetic model works best which considers the irreducible water volume and different pore sizes. For pure quartz sandstones without clay minerals, we use the same model for low water saturations, but for high water saturations a modified geometric model. A clayey sandstone rich in feldspath shows a different behaviour which cannot be explained by simple models. A better understanding will require measurements on additional samples which will help to improve the derived correlations and substantiate our findings.

Dependence of Thermal Conductivity on Water Saturation of Sandstones

NASA Astrophysics Data System (ADS)

Fehr, A.; Jorand, R.; Koch, A.; Clauser, C.

2008-12-01

Information on thermal conductivity of rocks and soils is essential in applied geothermal and hydrocarbon maturation research. In this study, we investigate the dependence of thermal conductivity on the degree of water saturation. Measurements were made on five sandstones from different outcrops in Germany. In a first step, we characterized the samples with respect to mineralogical composition, porosity, and microstructure by nuclear magnetic resonance (NMR) and mercury injection. We measured thermal conductivity with an optical scanner at different levels of water saturation. Finally we present a simple and easy model for the correlation of thermal conductivity and water saturation. Thermal conductivity decreases in the course of the drying of the rock. This behaviour is not linear and depends on the microstructure of the studied rock. We studied different mixing models for three phases: mineral skeleton, water and air. For argillaceous sandstones a modified arithmetic model works best which considers the irreducible water volume and different pore sizes. For pure quartz sandstones without clay minerals, we use the same model for low water saturations, but for high water saturations a modified geometric model. A clayey sandstone rich in feldspath shows a different behaviour which cannot be explained by simple models. A better understanding will require measurements on additional samples which will help to improve the derived correlations and substantiate our findings.

Capillary-Driven Solute Transport and Precipitation in Porous Media during Dry-Out

NASA Astrophysics Data System (ADS)

Ott, Holger; Andrew, Matthew; Blunt, Martin; Snippe, Jeroen

2014-05-01

The injection of dry or under-saturated gases or supercritical (SC) fluids into water bearing formations might lead to a formation dry-out in the vicinity of the injection well. The dry-out is caused by the evaporation/dissolution of formation water into the injected fluid and the subsequent transport of dissolved water in the injected fluid away from the injection well. Dry-out results in precipitation from solutes of the formation brine and consequently leads to a reduction of the rock's pore space (porosity) and eventually to a reduction of permeability near the injection well, or even to the loss of injectivity. Recently evidence has been found that the complexity of the pore space and the respective capillary driven solute transport plays a key role. While no effective-permeability (Keff) reduction was observed in a single-porosity sandstone, multi porosity carbonate rocks responded to precipitation with a strong reduction of Keff. The reason for the different response of Keff to salt precipitation is suspected to be in the exact location of the precipitate (solid salt) in the pore space. In this study, we investigate dry-out and salt precipitation due to supercritical CO2 injection in single and multi-porosity systems under near well-bore conditions. We image fluid saturation changes by means of μCT scanning during desaturation. We are able to observe capillary driven transport of the brine phase and the respective transport of solutes on the rock's pore scale. Finally we have access to the precipitated solid-salt phase and their distribution. The results can proof the thought models behind permeability porosity relationships K(φ) for injectivity modeling. The topic and the mechanisms we show are of general interest for drying processes in porous material such as soils and paper.

Salts in the dry valleys of Antartica

NASA Technical Reports Server (NTRS)

Gibson, E. K., Jr.; Presley, B. J.; Hatfield, J.

1984-01-01

The Dry Valleys of Antarctica are examples of polar deserts which are rare geological features on the Earth. Such deserts typically have high salinities associated with their closed-basin waters and on many surficial materials throughout them. In order to examine the possible sources for the salts observed in association with the soils in the Dry Valleys. The chloride and bromide concentrations of the water leachates from 58 soils and core samples were measured. The Cl/Br ratio for seawater is 289 and ratios measured for most of the 58 soils studied (greater than 85% of the soils studied) was larger than the seawater ratio (ratios typically were greater than 1000 and ranged up to 50,000). The enrichment in Cl relative to Br is strong evidence that the alts present within the soils were derived from seawater during ordinary evaporation processes, and not from the deposition of Cl and Br from aerosols or from rock weathering as has often been suggested.

Geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado

USGS Publications Warehouse

Shroba, Ralph R.; Kellogg, Karl S.; Brandt, Theodore R.

2014-01-01

The geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado, portrays the geology in the upper Arkansas valley and along the lower flanks of the Sawatch Range and Mosquito Range near the town of Granite. The oldest rocks, exposed in the southern and eastern parts of the quadrangle, include gneiss and plutonic rocks of Paleoproterozoic age. These rocks are intruded by younger plutonic rocks of Mesoproterozoic age. Felsic hypabyssal dikes, plugs, and plutons, ranging in age from Late Cretaceous or Paleocene to late Oligocene, locally intruded Proterozoic rocks. A small andesite lava flow of upper Oligocene age overlies Paleoproterozoic rock, just south of the Twin Lakes Reservoir. Gravelly fluvial and fan deposits of the Miocene and lower Pliocene(?) Dry Union Formation are preserved in the post-30 Ma upper Arkansas valley graben, a northern extension of the Rio Grande rift. Mostly north-northwest-trending faults displace deposits of the Dry Union Formation and older rock units. Light detection and ranging (lidar) imagery suggests that two short faults, near the Arkansas River, may displace surficial deposits as young as middle Pleistocene. Surficial deposits of middle Pleistocene to Holocene age are widespread in the Granite quadrangle, particularly in the major valleys and on slopes underlain by the Dry Union Formation. The main deposits are glacial outwash and post-glacial alluvium; mass-movement deposits transported by creep, debris flow, landsliding, and rockfall; till deposited during the Pinedale, Bull Lake, and pre-Bull Lake glaciations; rock-glacier deposits; and placer-tailings deposits formed by hydraulic mining and other mining methods used to concentrate native gold. Hydrologic and geologic processes locally affect use of the land and locally may be of concern regarding the stability of buildings and infrastructure, chiefly in low-lying areas along and near stream channels and locally in areas of moderate to steep slopes. Low-lying areas along major and minor streams are subject to periodic stream flooding. Mass-movement deposits and deposits of the Dry Union Formation that underlie moderate to steep slopes are locally subject to creep, debris-flow deposition, and landsliding. Proterozoic rocks that underlie steep slopes are locally subject to rockfall. Sand and gravel resources for construction and other uses in and near the Granite quadrangle are present in outwash-terrace deposits of middle and late Pleistocene age along the Arkansas River and along tributary streams in glaciated valleys.

Deformation and the timing of gas generation and migration in the eastern Brooks Range foothills, Arctic National Wildlife Refuge, Alaska

USGS Publications Warehouse

Parris, T.M.; Burruss, R.C.; O'Sullivan, P. B.

2003-01-01

Along the southeast border of the 1002 Assessment Area in the Arctic National Wildlife Refuge, Alaska, an explicit link between gas generation and deformation in the Brooks Range fold and thrust belt is provided through petrographic, fluid inclusion, and stable isotope analyses of fracture cements integrated with zircon fission-track data. Predominantly quartz-cemented fractures, collected from thrusted Triassic and Jurassic rocks, contain crack-seal textures, healed microcracks, and curved crystals and fluid inclusion populations, which suggest that cement growth occurred before, during, and after deformation. Fluid inclusion homogenization temperatures (175-250??C) and temperature trends in fracture samples suggest that cements grew at 7-10 km depth during the transition from burial to uplift and during early uplift. CH4-rich (dry gas) inclusions in the Shublik Formation and Kingak Shale are consistent with inclusion entrapment at high thermal maturity for these source rocks. Pressure modeling of these CH4-rich inclusions suggests that pore fluids were overpressured during fracture cementation. Zircon fission-track data in the area record postdeposition denudation associated with early Brooks Range deformation at 64 ?? 3 Ma. With a closure temperature of 225-240??C, the zircon fission-track data overlap homogenization temperatures of coeval aqueous inclusions and inclusions containing dry gas in Kingak and Shublik fracture cements. This critical time-temperature relationship suggests that fracture cementation occurred during early Brooks Range deformation. Dry gas inclusions suggest that Shublik and Kingak source rocks had exceeded peak oil and gas generation temperatures at the time structural traps formed during early Brooks Range deformation. The timing of hydrocarbon generation with respect to deformation therefore represents an important exploration risk for gas exploration in this part of the Brooks Range fold and thrust belt. The persistence of gas high at thermal maturity levels suggests, however, that significant volumes of gas may have been generated.

Mobilization and Transport of Organic Compounds from Reservoir Rock and Caprock in Geological Carbon Sequestration Sites

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

Zhong, Lirong; Cantrell, Kirk J.; Mitroshkov, Alexandre V.

2014-05-06

Supercritical CO2 (scCO2) is an excellent solvent for organic compounds, including benzene, toluene, ethyl-benzene, and xylene (BTEX), phenols, and polycyclic aromatic hydrocarbons (PAHs). Monitoring results from geological carbon sequestration (GCS) field tests has shown that organic compounds are mobilized following CO2 injection. Such results have raised concerns regarding the potential for groundwater contamination by toxic organic compounds mobilized during GCS. Knowledge of the mobilization mechanism of organic compounds and their transport and fate in the subsurface is essential for assessing risks associated with GCS. Extraction tests using scCO2 and methylene chloride (CH2Cl2) were conducted to study the mobilization of volatilemore » organic compounds (VOCs, including BTEX), the PAH naphthalene, and n-alkanes (n-C20 – n-C30) by scCO2 from representative reservoir rock and caprock obtained from depleted oil reservoirs and coal from an enhanced coal-bed methane recovery site. More VOCs and naphthalene were extractable by scCO2 compared to the CH2Cl2 extractions, while scCO2 extractable alkane concentrations were much lower than concentrations extractable by CH2Cl2. In addition, dry scCO2 was found to extract more VOCs than water saturated scCO2, but water saturated scCO2 mobilized more naphthalene than dry scCO2. In sand column experiments, moisture content was found to have an important influence on the transport of the organic compounds. In dry sand columns the majority of the compounds were retained in the column except benzene and toluene. In wet sand columns the mobility of the BTEX was much higher than that of naphthalene. Based upon results determined for the reservoir rock, caprock, and coal samples studied here, the risk to aquifers from contamination by organic compounds appears to be relatively low; however, further work is necessary to fully evaluate risks from depleted oil reservoirs.« less

Energy monitoring and analysis during deformation of bedded-sandstone: use of acoustic emission.

PubMed

Wasantha, P L P; Ranjith, P G; Shao, S S

2014-01-01

This paper investigates the mechanical behaviour and energy releasing characteristics of bedded-sandstone with bedding layers in different orientations, under uniaxial compression. Cylindrical sandstone specimens (54 mm diameter and 108 mm height) with bedding layers inclined at angles of 10°, 20°, 35°, 55°, and 83° to the minor principal stress direction, were produced to perform a series of Uniaxial Compressive Strength (UCS) tests. One of the two identical sample sets was fully-saturated with water before testing and the other set was tested under dry conditions. An acoustic emission system was employed in all the testing to monitor the acoustic energy release during the whole deformation process of specimens. From the test results, the critical joint orientation was observed as 55° for both dry and saturated samples and the peak-strength losses due to water were 15.56%, 20.06%, 13.5%, 13.2%, and 13.52% for the bedding orientations 10°, 20°, 35°, 55°, and 83°, respectively. The failure mechanisms for the specimens with bedding layers in 10°, 20° orientations showed splitting type failure, while the specimens with bedding layers in 55°, 83° orientations were failed by sliding along a weaker bedding layer. The failure mechanism for the specimens with bedding layers in 35° orientation showed a mixed failure mode of both splitting and sliding types. Analysis of the acoustic energy, captured from the acoustic emission detection system, revealed that the acoustic energy release is considerably higher in dry specimens than that of the saturated specimens at any bedding orientation. In addition, higher energy release was observed for specimens with bedding layers oriented in shallow angles (which were undergoing splitting type failures), whereas specimens with steeply oriented bedding layers (which were undergoing sliding type failures) showed a comparatively less energy release under both dry and saturated conditions. Moreover, a considerable amount of energy dissipation before the ultimate failure was observed for specimens with bedding layers oriented in shallow angles under both dry and saturated conditions. These results confirm that when rock having bedding layers inclined in shallow angles the failures could be more violent and devastative than the failures of rock with steeply oriented bedding layers. Copyright © 2013 Elsevier B.V. All rights reserved.

Organic and clay mineral diagenesis in Neogene sediments of western Taiwan

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

Hsueh, C.M.

1985-01-01

Three deep wells (two in the northern region and one in the southern region) with completion depths of over 5000m have been selected and the rock samples thoroughly examined. The TOC data of most samples studied are less than 1%, which is the TOC of an average shale. The low TOC is unfavorable for the Neogene sediments in western Taiwan as good source rocks. The data of C,H elemental analysis and Rock-Eval pyrolysis imply that the quality of kerogen in the northern region inclines to type II wet-gas prone, and in the southern region inclines to type III dry-gas prone.more » The maturity parameters of bitumen ratio, vitrinite reflectance, Tmax of Rock-Eval pyrolysis, and TTI of Lopatin's method show that the threshold of the oil-generative zone (about 0.6% Ro) in the northern region is in middle Miocene (about 3000m) and in the southern region is in lower Pliocene (about 4500m). The result of clay mineral analysis reveals that the transformation of smectitic clays to ordered mixed-layered smectite-illite can be identified and correlated with 0.6% Ro vitrinite reflectance. The illite crystallinity values are in the range of incipient to weak metamorphism and decrease with burial depth implying that the source area of low-grade metamorphic rocks has been uplifted rapidly so that the erosion from the exposed source area where the metamorphic grade became higher and higher was sufficiently fast to prevent weathering of illite. The Neogene sediments studied would not be expected to generate substantial amounts of oil. However, it can be expected that the pre-Miocene sediments in the northern region and the pre-Pliocene sediments in the southern region should have generated substantial amounts of gas at deeper depths.« less

Crystals May Have Formed in Drying Martian Lake

NASA Image and Video Library

2014-12-08

Lozenge-shaped crystals are evident in this magnified view of a Martian rock target called Mojave, taken on Nov. 15, 2014, by NASA Curiosity Mars rover. These features record concentration of dissolved salts, possibly in a drying lake.

New Insights From Whole Rock and Mineral Data on the Magmatic and Tectonic Evolution of the Columbia River Basalt Group (USA)

NASA Astrophysics Data System (ADS)

Caprarelli, G.; Reidel, S. P.

2004-12-01

The Miocene Columbia River Basalt Group (CRBG) of north-western USA was emplaced in a geologically dynamic setting characterized by a close association between magmatism and lithospheric thinning and rifting. We present and discuss electron probe microanalysis and XRFA data obtained from samples spanning the entire sequence of the CRBG. The examined basalts have near-aphyric textures. No glass is present, and plagioclase and augitic clinopyroxene are dominant matrix and groundmass phases. Plagioclase microcrysts are labradoritic to bytownitic. Whole rock compositions were taken as proxies of the liquid compositions. Application of plagioclase / melt and clinopyroxene / melt geothermobarometers indicated that during crustal ascent the magmas were dry, and that pre-eruptive pressures and temperatures ranged from 0 to 0.66 GPa and 1393 to 1495 K, respectively. In a P-T diagram most of the samples are distributed along a general CRBG trend, while some samples plot along a parallel higher temperature trend. The calculated P-T values, the positive correlation between calculated P and T, and no horizontal alignment of the data, exclude the presence of upper crustal solidification fronts, and indicate that magma aggregation zones were located deeper than 25 km, plausibly immediately below the Moho, that in this region is at a depth of approximately 35 km. Episodic stretching of the lithosphere best explains the observed parallel P-T trends. Whole rock major element abundances resulted from fractional crystallization of the magmas during ascent. To retrieve the compositions of the primitive melts we added to the bulk rock compositions variable amounts of magnesian olivine [Mg/(Mg+Fe) = 0.88], and derived the evolution of olivine fractionating magmas in equilibrium with mantle harzburgite. Two groups of samples were found, corresponding to the parallel P-T trends obtained from mineral / melt calculations. The highest temperature trend corresponds to samples whose calculated primitive compositions are in agreement with those obtained from peridotite melting experiments (as published in the relevant literature). Interpretation of results for rocks belonging to the general CRBG trend suggests, either: (a) that higher forsteritic content olivine should be used in the calculations; or, (b) that melt / ol / opx reactions occurred. Investigation of the CRBG primitive compositions has relevance with regard to the geodynamic evolution models of this region. We are currently undertaking melt inclusion studies of suitable CRBG samples.

Endolithic microbial life in extreme cold climate: snow is required, but perhaps less is more.

PubMed

Sun, Henry J

2013-04-03

Cyanobacteria and lichens living under sandstone surfaces in the McMurdo Dry Valleys require snow for moisture. Snow accumulated beyond a thin layer, however, is counterproductive, interfering with rock insolation, snow melting, and photosynthetic access to light. With this in mind, the facts that rock slope and direction control colonization, and that climate change results in regional extinctions, can be explained. Vertical cliffs, which lack snow cover and are perpetually dry, are devoid of organisms. Boulder tops and edges can trap snow, but gravity and wind prevent excessive buildup. There, the organisms flourish. In places where snow-thinning cannot occur and snow drifts collect, rocks may contain living or dead communities. In light of these observations, the possibility of finding extraterrestrial endolithic communities on Mars cannot be eliminated.

Potential for leaching of arsenic from excavated rock after different drying treatments.

PubMed

Li, Jining; Kosugi, Tomoya; Riya, Shohei; Hashimoto, Yohey; Hou, Hong; Terada, Akihiko; Hosomi, Masaaki

2016-07-01

Leaching of arsenic (As) from excavated rock subjected to different drying methods is compared using sequential leaching tests and rapid small-scale column tests combined with a sequential extraction procedure. Although the total As content in the rock was low (8.81 mg kg(-1)), its resulting concentration in the leachate when leached at a liquid-to-solid ratio of 10 L kg(-1) exceeded the environmental standard (10 μg L(-1)). As existed mainly in dissolved forms in the leachates. All of the drying procedures applied in this study increased the leaching of As, with freeze-drying leading to the largest increase. Water extraction of As using the two tests showed different leaching behaviors as a function of the liquid-to-solid ratio, and achieved average extractions of up to 35.7% and 25.8% total As, respectively. Dissolution of As from the mineral surfaces and subsequent re-adsorption controlled the short-term release of As; dissolution of Fe, Al, and dissolved organic carbon played important roles in long-term As leaching. Results of the sequential extraction procedure showed that use of 0.05 M (NH4)2SO4 underestimates the readily soluble As. Long-term water extraction removed almost all of the non-specifically sorbed As and most of the specifically sorbed As. The concept of pollution potential indices, which are easily determined by the sequential leaching test, is proposed in this study and is considered for possible use in assessing efficacy of treatment of excavated rocks. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electrical conductivity of Icelandic deep geothermal reservoirs: insight from HT-HP laboratory experiments

NASA Astrophysics Data System (ADS)

Nono, Franck; Gibert, Benoit; Loggia, Didier; Parat, Fleurice; Azais, Pierre; Cichy, Sarah

2016-04-01

Although the Icelandic geothermal system has been intensively investigated over the years, targeting increasingly deeper reservoirs (i.e. under supercritical conditions) requires a good knowledge of the behaviour of physical properties of the host rock in order to better interpret large scale geophysical observations. In particular, the interpretation of deep electrical soundings remains controversial as only few studies have investigated the influence of altered minerals and pore fluid properties on electrical properties of rocks at high temperature and pressure. In this study, we investigate the electrical conductivity of drilled samples from different Icelandic geothermal fields at elevated temperature, confining pressure and pore pressure conditions (100°C < T < 600°C, confining pressure up to 100 MPa and pore pressure up to 35 MPa). The investigated rocks are composed of hyaloclastites, dolerites and basalts taken from depths of about 800 m for the hyaloclastites, to almost 2500 m for the dolerites. They display different porosity structures, from vuggy and intra-granular to micro-cracked porosities, and have been hydrothermally alterated in the chlorite to amphibolite facies. Electrical conductivity measurements are first determined at ambient conditions as a function of pore fluid conductivity in order to establish their relationships with lithology and pore space topology, prior to the high pressure and temperature measurements. Cementation factor varies from 1.5 for the dolerites to 2.83 for the basalt, reflecting changes in the shape of the conductive channels. The surface conductivities, measured at very low fluid conductivity, increases with the porosity and is correlated with the cation exchange capacity. At high pressure and temperature, we used the two guard-ring electrodes system. Measurements have been performed in dry and saturated conditions as a function of temperature and pore pressure. The supercritical conditions have been investigated and temperature cycles have been performed systematically. Dry electrical conductivity measurements show for most of the samples irreversible changes when temperatures exceed 500°C. These changes are interpreted as destabilization/dehydration of alteration minerals that could lead to the presence of a conductive fluid phase in the samples. Very low and high salinity (NaCl) electrical conductivity measurements have been performed as a function of temperature. At supercritical conditions, electrical conductivity at low salinity is not pore pressure dependent and surface conduction is preponderant. At saturated conditions, the rock's electrical conductivity increases linearly (as a function of T-1) until 350°C. Above 350°C, the conductivity decreases. All rock types exhibit the same increasing rate. This work was funded by the of the EC project IMAGE (Integrated Methods for Advanced Geothermal Exploration, grant agreement No. 608553).

Comparative analysis of cyanobacteria inhabiting rocks with different light transmittance in the Mojave Desert: a Mars terrestrial analogue

NASA Astrophysics Data System (ADS)

Smith, Heather D.; Baqué, Mickael; Duncan, Andrew G.; Lloyd, Christopher R.; McKay, Christopher P.; Billi, Daniela

2014-05-01

The Mojave Desert has been long considered a suitable terrestrial analogue to Mars in many geological and astrobiological aspects. The Silver Lake region in the Mojave Desert hosts several different rock types (talc, marble, quartz, white carbonate and red-coated carbonate) colonized by hypoliths within a few kilometres. This provides an opportunity to investigate the effect of rock type on hypolithic colonization in a given environment. Transmission measurements from 300 to 800 nm showed that the transmission of blue and UVA varied between rock types. The wavelength at which the transmission fell to 1% of the transmission at 600 nm was 475 nm for white carbonate and quartz, 425 nm for red-coated carbonate and talc and 380 nm for marble. The comparative analysis of the cyanobacterial component of hypoliths under different rocks, as revealed by sequencing 16S rRNA gene clone libraries, showed no significant variation with rock type; hypoliths were dominated by phylotypes of the genus Chroococcidiopsis, although less abundant phylotypes of the genus Loriellopsis, Leptolyngbya and Scytonema occurred. The comparison of the confocal laser scanning microscopy-λ (CLSM-λ) scan analysis of the spectral emission of the photosynthetic pigments of Chroococcidiopsis in different rocks with the spectrum of isolated Chroococcidiopsis sp. 029, revealed a 10 nm red shift in the emission fingerprinting for quartz and carbonate and a 5 nm red shift for talc samples. This result reflects the versatility of Chroococcidiopsis in inhabiting dry niches with different light availability for photosynthesis.

Oil sands thickened froth treatment tailings exhibit acid rock drainage potential during evaporative drying.

PubMed

Kuznetsov, Petr; Kuznetsova, Alsu; Foght, Julia M; Siddique, Tariq

2015-02-01

Bitumen extraction from oil sands ores after surface mining produces different tailings waste streams: 'froth treatment tailings' are enriched in pyrite relative to other streams. Tailings treatment can include addition of organic polymers to produce thickened tailings (TT). TT may be further de-watered by deposition into geotechnical cells for evaporative drying to increase shear strength prior to reclamation. To examine the acid rock drainage (ARD) potential of TT, we performed predictive analyses and laboratory experiments on material from field trials of two types of thickened froth treatment tailings (TT1 and TT2). Acid-base accounting (ABA) of initial samples showed that both TT1 and TT2 initially had net acid-producing potential, with ABA values of -141 and -230 t CaCO₃ equiv. 1000 t(-1) of TT, respectively. In long-term kinetic experiments, duplicate ~2-kg samples of TT were incubated in shallow trays and intermittently irrigated under air flow for 459 days to simulate evaporative field drying. Leachates collected from both TT samples initially had pH~6.8 that began decreasing after ~50 days (TT2) or ~250 days (TT1), stabilizing at pH~2. Correspondingly, the redox potential of leachates increased from 100-200 mV to 500-580 mV and electrical conductivity increased from 2-5 dS m(-1) to 26 dS m(-1), indicating dissolution of minerals during ARD. The rapid onset and prolonged ARD observed with TT2 is attributed to its greater pyrite (13.4%) and lower carbonate (1.4%) contents versus the slower onset of ARD in TT1 (initially 6.0% pyrite and 2.5% carbonates). 16S rRNA gene pyrosequencing analysis revealed rapid shift in microbial community when conditions became strongly acidic (pH~2) favoring the enrichment of Acidithiobacillus and Sulfobacillus bacteria in TT. This is the first report showing ARD potential of TT and the results have significant implications for effective management of pyrite-enriched oil sands tailings streams/deposits. Copyright © 2014 Elsevier B.V. All rights reserved.

Resistance of Antarctic black fungi and cryptoendolithic communities to simulated space and Martian conditions

PubMed Central

Onofri, S.; Barreca, D.; Selbmann, L.; Isola, D.; Rabbow, E.; Horneck, G.; de Vera, J.P.P.; Hatton, J.; Zucconi, L.

2008-01-01

Dried colonies of the Antarctic rock-inhabiting meristematic fungi Cryomyces antarcticus CCFEE 515, CCFEE 534 and C. minteri CCFEE 5187, as well as fragments of rocks colonized by the Antarctic cryptoendolithic community, were exposed to a set of ground-based experiment verification tests (EVTs) at the German Aerospace Center (DLR, Köln, Germany). These were carried out to test the tolerance of these organisms in view of their possible exposure to space conditions outside of the International Space Station (ISS). Tests included single or combined simulated space and Martian conditions. Responses were analysed both by cultural and microscopic methods. Thereby, colony formation capacities were measured and the cellular viability was assessed using live/dead dyes FUN 1 and SYTOX Green. The results clearly suggest a general good resistance of all the samples investigated. C. minteri CCFEE 5187, C. antarcticus CCFEE 515 and colonized rocks were selected as suitable candidates to withstand space flight and long-term permanence in space on the ISS in the framework of the LIchens and Fungi Experiments (LIFE programme, European Space Agency). PMID:19287532

Quantifying Seasonal Dynamic Water Storage in a Fractured Bedrock Vadose Zone With Borehole Nuclear Magnetic Resonance

NASA Astrophysics Data System (ADS)

Schmidt, L.; Minton, B.; Soto-Kerans, N.; Rempe, D.; Heidari, Z.

2017-12-01

In many uplands landscapes, water is transiently stored in the weathered and fractured bedrock that underlies soils. The timing and spatial pattern of this "rock moisture" has strong implications for ecological and biogeochemical processes that influence global cycling of water and solutes. However, available technologies for direct monitoring of rock moisture are limited. Here, we quantify temporal and spatial changes in rock moisture at the field scale across thick (up to 20 m) fractured vadose zone profiles using a novel narrow diameter borehole nuclear magnetic resonance system (BNMR). Successive BNMR surveys were performed using the Vista Clara Inc. Dart system in a network of boreholes within two steep, intensively hydrologically monitored hillslopes associated with the Eel River Critical Zone Observatory (ERCZO) in Northern California. BNMR data showed agreement with estimates of the temporal and spatial pattern of rock moisture depletion over the dry season via downhole neutron and gamma density surveys, as well as permanently installed continuous time domain reflectometry. Observable shifts in the BNMR-derived T2 distribution over time provide a direct measure of changes in the amount of water held within different pore sizes (large vs. small) in fractured rock. Analysis of both BNMR and laboratory-scale NMR (using a 2MHz benchtop NMR spectrometer) measurements of ERCZO core samples at variable saturation suggest that rock moisture changes associated with summer depletion occur within both large (fracture) and small (matrix) pore sizes. Collectively, our multi-method field- and laboratory- scale measurements highlight the potential for BNMR to improve quantification of rock moisture storage for better understanding of the biogeochemical and ecohydrological implications of rock moisture circulation in the Critical Zone.

Chronology of rock falls and slides in a desert mountain range: Case study from the Sonoran Desert in south-central Arizona

NASA Astrophysics Data System (ADS)

Dorn, Ronald I.

2014-10-01

In order to respond to the general paucity of information on the chronology of ubiquitous small rock falls and slides that litter the slopes of desert mountain ranges, a case study in the Sonoran Desert reveals new insight into the desert geomorphology of mountain slopes. Rock falls and rock slides in the McDowell Mountains that abut metropolitan Phoenix, USA, fall in three chronometric groupings dated by conventional radiocarbon and rock varnish microlamination methods. First, the oldest events are > 74 ka and take the form of stable colluvial boulder fields - positive relief features that are tens of meters long and a few meters wide. Second, randomly sampled slides and falls of various sizes and positions wasted during wetter periods of the terminal Pleistocene and Holocene. Third, an anomalous clustering of slides and falls occurred during the late Medieval Warm Period (Medieval Climatic Anomaly) when an extreme storm was a possible but unlikely trigger. One speculative hypothesis for the cluster of Medieval Warm Period events is that a small to moderate sized earthquake shook heavily shattered bedrock - close to failure - just enough to cause a spate of rock falls and slides. A second speculative hypothesis is that this dry period enhanced physical weathering processes such as dirt cracking. However, the reasons for the recent clustering of rock falls remain enigmatic. While the temporal distribution of slides and falls suggests a minimal hazard potential for homes and roads on the margins of the McDowell Mountains, this finding may not necessary match other desert ranges in metropolitan Phoenix or mountains with different rock types and structures that abut other arid urban centers.

Micro-fabric damages in Boom Clay inferred from cryo-BIB-SEM experiment: recent results

NASA Astrophysics Data System (ADS)

Desbois, Guillaume; Schmatz, Joyce; Klaver, Jop; Urai, Janos L.

2017-04-01

The Boom Clay is considered as a potential host rock in Belgium for nuclear waste disposal in a deep geological formation. One of the keys to understand the long-term performance of such a host rock is the fundamental understanding of coupling between microstructural evolution, poromechanical behaviour and the state of hydration of the system. At in situ conditions, Boom Clay is a nearly water-saturated (>94%) clay-rich geomaterial. Subsequently, for measurement of mechanical and transport properties in laboratory, cores of Boom Clay are vacuum-packed in Al-coated-poly-ethylene barrier foil to be best preserved at original hydric state. Because clay microstructures are very sensitive to dehydration, the validity of investigations done on such preserved or/and dried samples is often questionable. Desbois et al. (2009, 2013, 2014) showed the possibility to image fluid-filled porosity in Boom Clay, by using the FIB-cryo-SEM (FIB: Focussed Ion Beam) and FIB-cryo-SEM (BIB: Broad Ion Beam) techniques. However, surprisingly in Desbois et al. (2014), BIB-cryo-SEM experiments on Boom Clay, shown that the majority of the pores were fluid-free, contrasting with result in Desbois et al. (2009). In Desbois et al. (2014), several reasons were discussed to explain such discrepancies. The likely ones are the sealing efficiency of the Al-barrier foil at long term and the volume expansion due to the release of in-situ stress after core extraction, contributing both to dehydration and microfabric damage. This contribution presents the newest results based on cryo-BIB-SEM. Small pieces (30 mm3) of Boom Clay were preserved in liquid nitrogen after the core extraction at the MOL/Dessel Underground Research Laboratory in Belgium. A maximum of ten minutes time span was achieved between opening the core, the sub-sample extraction and the quenching of sub-samples in liquid nitrogen. First results show that all pores visible at cryo-SEM resolution are water saturated. However, water-filled micro-cracks are also present and they are interpreted to result from the releasing of in-situ stress after the core extraction. Moreover, the comparison of the clay micro-fabrics in the same preserved and dried sample suggests collapsing of the clay aggregates' pores in dried sample. These newest results are still preliminary and they need to be analysed in more details. However, if they are confirmed they may be important input to discuss about the validity of measurement of mechanical and transport properties done in laboratory. Desbois G., Urai J.L. and Kukla P.A. (2009). Morphology of the pore space in claystones - evidence from BIB/FIB ion beam sectioning and cryo-SEM observations. E-Earth, 4 :15-22. Desbois G., J.L. Urai, F. Pérez-Willard, Z. Radi, S. van Offern, I. Burkart, P.A. Kukla, U. Wollenberg (2013). Argon broad ion beam tomography in a cryogenic scanning electron microscope: a novel tool for the investigation of representative microstructures in sedimentary rocks containing pore fluid. Journal of Microscopy, 249(3): 215-235. Desbois G., Urai J.L., Hemes S., Brassinnes S., De Craen M., Sillen X. (2014). Nanometer-scale pore fluid distribution and drying damage in preserved clay cores from Belgian clay formations inferred by BIB-cryo-SEM. Engineering Geology, 170:117-131.

Dynamic tensile-failure-induced velocity deficits in rock

NASA Technical Reports Server (NTRS)

Rubin, Allan M.; Ahrens, Thomas J.

1991-01-01

Planar impact experiments were employed to induce dynamic tensile failure in Bedford limestone. Rock disks were impacted with aluminum and polymethyl methacralate (PMMA) flyer plates at velocities of 10 to 25 m/s. Tensile stress magnitudes and duration were chosen so as to induce a range of microcrack growth insufficient to cause complete spalling of the samples. Ultrasonic P- and S-wave velocities of recovered targets were compared to the velocities prior to impact. Velocity reduction, and by inference microcrack production, occurred in samples subjected to stresses above 35 MPa in the 1.3 microsec PMMA experiments and 60 MPa in the 0.5 microsec aluminum experiments. Using a simple model for the time-dependent stress-intensity factor at the tips of existing flaws, apparent fracture toughnesses of 2.4 and 2.5 MPa sq rt m are computed for the 1.3 and 0.5 microsec experiments. These are a factor of about 2 to 3 greater than quasi-static values. The greater dynamic fracture toughness observed may result from microcrack interaction during tensile failure. Data for water-saturated and dry targets are indistinguishable.

Pore-Scale Modeling of Pore Structure Effects on P-Wave Scattering Attenuation in Dry Rocks

PubMed Central

Li, Tianyang; Qiu, Hao; Wang, Feifei

2015-01-01

Underground rocks usually have complex pore system with a variety of pore types and a wide range of pore size. The effects of pore structure on elastic wave attenuation cannot be neglected. We investigated the pore structure effects on P-wave scattering attenuation in dry rocks by pore-scale modeling based on the wave theory and the similarity principle. Our modeling results indicate that pore size, pore shape (such as aspect ratio), and pore density are important factors influencing P-wave scattering attenuation in porous rocks, and can explain the variation of scattering attenuation at the same porosity. From the perspective of scattering attenuation, porous rocks can safely suit to the long wavelength assumption when the ratio of wavelength to pore size is larger than 15. Under the long wavelength condition, the scattering attenuation coefficient increases as a power function as the pore density increases, and it increases exponentially with the increase in aspect ratio. For a certain porosity, rocks with smaller aspect ratio and/or larger pore size have stronger scattering attenuation. When the pore aspect ratio is larger than 0.5, the variation of scattering attenuation at the same porosity is dominantly caused by pore size and almost independent of the pore aspect ratio. These results lay a foundation for pore structure inversion from elastic wave responses in porous rocks. PMID:25961729

Direct observations of rock moisture, a hidden component of the hydrologic cycle.

PubMed

Rempe, Daniella M; Dietrich, William E

2018-03-13

Recent theory and field observations suggest that a systematically varying weathering zone, that can be tens of meters thick, commonly develops in the bedrock underlying hillslopes. Weathering turns otherwise poorly conductive bedrock into a dynamic water storage reservoir. Infiltrating precipitation typically will pass through unsaturated weathered bedrock before reaching groundwater and running off to streams. This invisible and difficult to access unsaturated zone is virtually unexplored compared with the surface soil mantle. We have proposed the term "rock moisture" to describe the exchangeable water stored in the unsaturated zone in weathered bedrock, purposely choosing a term parallel to, but distinct from, soil moisture, because weathered bedrock is a distinctly different material that is distributed across landscapes independently of soil thickness. Here, we report a multiyear intensive campaign of quantifying rock moisture across a hillslope underlain by a thick weathered bedrock zone using repeat neutron probe measurements in a suite of boreholes. Rock moisture storage accumulates in the wet season, reaches a characteristic upper value, and rapidly passes any additional rainfall downward to groundwater. Hence, rock moisture storage mediates the initiation and magnitude of recharge and runoff. In the dry season, rock moisture storage is gradually depleted by trees for transpiration, leading to a common lower value at the end of the dry season. Up to 27% of the annual rainfall is seasonally stored as rock moisture. Significant rock moisture storage is likely common, and yet it is missing from hydrologic and land-surface models used to predict regional and global climate.

IS ISLAND PARK A HOT DRY ROCK SYSTEM?

USGS Publications Warehouse

Hoover, D.B.; Pierce, Herbert A.; Long, C.L.

1985-01-01

The Island Park-Yellowstone National Park region comprises a complex caldera system which has formed over the last 2 m. y. The caldera system has been estimated to contain 50% of the total thermal energy remaining in all young igneous systems in the United States. As the result of a reexamination of the data and recent electrical work in the area, the authors now postulate that much of the area where the first- and second-stage calderas developed is underlain by a solidified but still hot pluton. They postulate that the pluton represents a significant hot-dry-rock resource for the United States.

Endolithic Microbial Life in Extreme Cold Climate: Snow Is Required, but Perhaps Less Is More

PubMed Central

Sun, Henry J.

2013-01-01

Cyanobacteria and lichens living under sandstone surfaces in the McMurdo Dry Valleys require snow for moisture. Snow accumulated beyond a thin layer, however, is counterproductive, interfering with rock insolation, snow melting, and photosynthetic access to light. With this in mind, the facts that rock slope and direction control colonization, and that climate change results in regional extinctions, can be explained. Vertical cliffs, which lack snow cover and are perpetually dry, are devoid of organisms. Boulder tops and edges can trap snow, but gravity and wind prevent excessive buildup. There, the organisms flourish. In places where snow-thinning cannot occur and snow drifts collect, rocks may contain living or dead communities. In light of these observations, the possibility of finding extraterrestrial endolithic communities on Mars cannot be eliminated. PMID:24832803

Experimental investigation of geochemical and mineralogical effects of CO2 sequestration on flow characteristics of reservoir rock in deep saline aquifers

PubMed Central

Rathnaweera, T. D.; Ranjith, P. G.; Perera, M. S. A.

2016-01-01

Interactions between injected CO2, brine, and rock during CO2 sequestration in deep saline aquifers alter their natural hydro-mechanical properties, affecting the safety, and efficiency of the sequestration process. This study aims to identify such interaction-induced mineralogical changes in aquifers, and in particular their impact on the reservoir rock’s flow characteristics. Sandstone samples were first exposed for 1.5 years to a mixture of brine and super-critical CO2 (scCO2), then tested to determine their altered geochemical and mineralogical properties. Changes caused uniquely by CO2 were identified by comparison with samples exposed over a similar period to either plain brine or brine saturated with N2. The results show that long-term reaction with CO2 causes a significant pH drop in the saline pore fluid, clearly due to carbonic acid (as dissolved CO2) in the brine. Free H+ ions released into the pore fluid alter the mineralogical structure of the rock formation, through the dissolution of minerals such as calcite, siderite, barite, and quartz. Long-term CO2 injection also creates a significant CO2 drying-out effect and crystals of salt (NaCl) precipitate in the system, further changing the pore structure. Such mineralogical alterations significantly affect the saline aquifer’s permeability, with important practical consequences for the sequestration process. PMID:26785912

Applications of NTNU/SINTEF Drillability Indices in Hard Rock Tunneling

NASA Astrophysics Data System (ADS)

Zare, S.; Bruland, A.

2013-01-01

Drillability indices, i.e., the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), Cutter Life Index™ (CLI), and Vickers Hardness Number Rock (VHNR), are indirect measures of rock drillability. These indices are recognized as providing practical characterization of rock properties used in the Norwegian University of Science and Technology (NTNU) time and cost prediction models available for hard rock tunneling and surface excavation. The tests form the foundation of various hard rock equipment capacity and performance prediction methods. In this paper, application of the tests for tunnel boring machine (TBM) and drill and blast (D&B) tunneling is investigated and the impact of the indices on excavation time and costs is presented.

Peralkaline- and calc-alkaline-hosted volcanogenic massive sulfide deposits of the Bonnifield District, East-Central Alaska

USGS Publications Warehouse

Dusel-Bacon, Cynthia; Foley, Nora K.; Slack, John E.; Koenig, Alan E.; Oscarson, Robert L.

2012-01-01

Volcanogenic massive sulfide (VMS) Zn-Pb-Cu-Ag-Au deposits of the Bonnifield mining district formed during Late Devonian-Early Mississippian magmatism along the western edge of Laurentia. The largest deposits, Dry Creek and WTF, have a combined resource of 5.7 million tonnes at 10% Zn, 4% Pb, 0.3% Cu, 300 grams per tonne (g/t) Ag, and 1.6 g/t Au. These polymetallic deposits are hosted in high field strength element (HFSE)- and rare-earth element (REE)-rich peralkaline (pantelleritic) metarhyolite, and interlayered pyritic argillite and mudstone of the Mystic Creek Member of the Totatlanika Schist Formation. Mystic Creek metarhyolite and alkali basalt (Chute Creek Member) constitute a bimodal pair that formed in an extensional environment. A synvolcanic peralkaline quartz porphyry containing veins of fluorite, sphalerite, pyrite, and quartz intrudes the central footwall at Dry Creek. The Anderson Mountain deposit, located ~32 km to the southwest, occurs within calc-alkaline felsic to intermediate-composition metavolcanic rocks and associated graphitic argillite of the Wood River assemblage. Felsic metavolcanic rocks there have only slightly elevated HFSEs and REEs. The association of abundant graphitic and siliceous argillite with the felsic volcanic rocks together with low Cu contents in the Bonnifield deposits suggests classification as a siliciclastic-felsic type of VMS deposit. Bonnifield massive sulfides and host rocks were metamorphosed and deformed under greenschist-facies conditions in the Mesozoic. Primary depositional textures, generally uncommon, consist of framboids, framboidal aggregates, and spongy masses of pyrite. Sphalerite, the predominant base metal sulfide, encloses early pyrite framboids. Galena and chalcopyrite accompanied early pyrite formation but primarily formed late in the paragenetic sequence. Silver-rich tetrahedrite is a minor late phase at the Dry Creek deposit. Gold and Ag are present in low to moderate amounts in pyrite from all of the deposits; electrum inclusions occur in Dry Creek sphalerite. Contents and ratios of trace elements in graphitic argillite that serve as proxies for the redox state of the bottom waters in the basin indicate that Dry Creek mineralization took place in suboxic to periodically anoxic bottom waters. Trace element data show higher contents of Tl-Mn-As in pyrite from the Anderson Mountain deposit compared to the Dry Creek or WTF deposits and thus suggest that Anderson Mountain may have formed at lower temperatures or under slightly more oxidizing conditions. No exact modern analogue for the tectonic setting of the Bonnifield VMS deposits is known, although the back-arc regions of the Okinawa Trough and Woodlark Basin satisfy the requirement for a submarine, extensional setting adjacent to a continental margin. Limited occurrences of peralkaline volcanic rocks occur in these two potential analogues, but the peralkalinity of those rocks is much less than that of the Mystic Creek Member metarhyolites in the Bonnifield district. The highly elevated trace element (e.g., Zr, Nb) contents of Mystic Creek metarhyolites suggest that a better analogue may be a submarine rifted continental margin. The calc-alkaline composition of the host rocks to the Anderson Mountain deposit suggests that mineralization there formed in a continental margin arc, outboard of the extended continental margin setting of the peralkaline-hosted Dry Creek and WTF deposits.

A comparative study on the characteristics of radioactivities and negative air ions originating from the minerals in some radon hot springs.

PubMed

Sakoda, Akihiro; Hanamoto, Katsumi; Haruki, Naoto; Nagamatsu, Tomohiro; Yamaoka, Kiyonori

2007-01-01

To elucidate the characteristics of some radon hot springs, we simulated a hot spring by soaking the rocks for the radon therapy in water and measured the concentrations of radon and negative air ions in various conditions. In the results, the individual rock structure could contribute to radon leaching because the radon leaching rates were independent of the grain sizes. More negative air ions were generated by the wet rocks than by the dry rocks.

Effects of bioleaching on the mechanical and chemical properties of waste rocks

NASA Astrophysics Data System (ADS)

Yin, Sheng-Hua; Wu, Ai-Xiang; Wang, Shao-Yong; Ai, Chun-Ming

2012-01-01

Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.

Spontaneous electric current flow during deformation of non-piezoelectric marble samples: an indicator of stress state?

NASA Astrophysics Data System (ADS)

Cartwright-Taylor, A. L.; Sammonds, P. R.; Vallianatos, F.

2016-12-01

We recorded spontaneous electric current flow in non-piezoelectric Carrara marble samples during triaxial deformation. Mechanical data, ultrasonic velocities and acoustic emissions were acquired simultaneously with electric current to constrain the relationship between electric current flow, differential stress and damage. Under strain-controlled loading, spontaneous electric current signals (nA) were generated and sustained under all conditions tested. In dry samples, a detectable electric current arises only during dilatancy and is correlated with the damage induced by microcracking. Signal variations with confining pressure correspond to microcrack suppression, while variations with strain rate are associated with time-dependent differences in deformation mechanism across the brittle to semi-brittle transition. In the brittle regime, the signal exhibits a precursory change as damage localises and the stress drop accelerates towards failure. This change is particularly distinct at dynamic strain rates. Similar changes are seen in the semi-brittle regime although the signal is more oscillatory in nature. Current flow in dry samples is proportional to stress within 90% of peak stress. In fluid-saturated samples proportionality holds from 40% peak stress, with a significant increase in the rate of current production from 90% peak stress associated with fluid flow during dilatancy. This direct relationship demonstrates that electric current could be used as a proxy for stress, indicating when the rock is reaching the limit of its strength. The experimental power law relationship between electric current and strain rate, which mirrors the power-law creep equation, supports this observation. High-frequency fluctuations of electric current are not normally distributed - they exhibit `heavy-tails'. We model these distributions with q-Gaussian statistics and evolution of the q-parameter during deformation reveals a two-stage precursory anomaly prior to sample failure, consistent with the acoustic emissions b-value and stress intensity evolution as modelled from fracture mechanics. Our findings support the idea that electric currents in the crust can be generated purely from solid state fracture processes and that these currents may reflect the stress state within the damaged rock.

VNIR reflectance spectroscopy of natural carbonate rocks: implication for remote sensing identification of fault damage zones

NASA Astrophysics Data System (ADS)

Traforti, Anna; Mari, Giovanna; Carli, Cristian; Demurtas, Matteo; Massironi, Matteo; Di Toro, Giulio

2017-04-01

Reflectance spectroscopy in the visible and near-infrared (VNIR) is a common technique used to study the mineral composition of Solar System bodies from remote sensed and in-situ robotic exploration. In the VNIR spectral range, both crystal field and vibrational overtone absorptions can be present with spectral characteristics (i.e. albedo, slopes, absorption band with different positions and depths) that vary depending on composition and texture (e.g. grain size, roughness) of the sensed materials. The characterization of the spectral variability related to the rock texture, especially in terms of grain size (i.e., both the size of rock components and the size of particulates), commonly allows to obtain a wide range of information about the different geological processes modifying the planetary surfaces. This work is aimed at characterizing how the grain size reduction associated to fault zone development produces reflectance variations in rock and mineral spectral signatures. To achieve this goal we present VNIR reflectance analysis of a set of fifteen rock samples collected at increasing distances from the fault core of the Vado di Corno fault zone (Campo Imperatore Fault System - Italian Central Apennines). The selected samples had similar content of calcite and dolomite but different grain size (X-Ray Powder Diffraction, optical and scanning electron microscopes analysis). Consequently, differences in the spectral signature of the fault rocks should not be ascribed to mineralogical composition. For each sample, bidirectional reflectance spectra were acquired with a Field-Pro Spectrometer mounted on a goniometer, on crushed rock slabs reduced to grain size <800, <200, <63, <10 μm and on intact fault zone rock slabs. The spectra were acquired on dry samples, at room temperature and normal atmospheric pressure. The source used was a Tungsten Halogen lamp with an illuminated spot area of ca. 0.5 cm2and incidence and emission angles of 30˚ and 0˚ respectively. The spectral analysis of the crushed and intact rock slabs in the VNIR spectral range revealed that in both cases, with increasing grain size: (i) the reflectance decreases (ii) VNIR spectrum slopes (i.e. calculated between wavelengths of 0.425 - 0.605 μm and 2.205 - 2.33 μm, respectively) and (iii) carbonate main absorption band depth (i.e. vibrational absorption band at wavelength of ˜2.3 μm) increase. In conclusion, grain size variations resulting from the fault zone evolution (e.g., cumulated slip or development of thick damage zones) produce reflectance variations in rocks and mineral spectral signatures. The remote sensing analysis in the VNIR spectral range can be applied to identify the spatial distribution and extent of fault core and damage zone domains for industrial and seismic hazard applications. Moreover, the spectral characterization of carbonate-built rocks can be of great interest for the surface investigation of inner planets (e.g. Earth and Mars) and outer bodies (e.g. Galilean icy satellites). On these surfaces, carbonate minerals at different grain sizes are common and usually related to water and carbon distribution, with direct implications for potential life outside Earth (e.g. Mars).

Visible-Near Infrared Point Spectrometry of Drill Core Samples from Río Tinto, Spain: Results from the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) Drilling Exercise

NASA Astrophysics Data System (ADS)

Sutter, Brad; Brown, Adrian J.; Stoker, Carol R.

2008-10-01

Sampling of subsurface rock may be required to detect evidence of past biological activity on Mars. The Mars Astrobiology Research and Technology Experiment (MARTE) utilized the Río Tinto region, Spain, as a Mars analog site to test dry drilling technologies specific to Mars that retrieve subsurface rock for biological analysis. This work examines the usefulness of visible-near infrared (VNIR) (450-1000 nm) point spectrometry to characterize ferric iron minerals in core material retrieved during a simulated Mars drilling mission. VNIR spectrometry can indicate the presence of aqueously precipitated ferric iron minerals and, thus, determine whether biological analysis of retrieved rock is warranted. Core spectra obtained during the mission with T1 (893-897 nm) and T2 (644-652 nm) features indicate goethite-dominated samples, while relatively lower wavelength T1 (832-880 nm) features indicate hematite. Hematite/goethite molar ratios varied from 0 to 1.4, and within the 880-898 nm range, T1 features were used to estimate hematite/goethite molar ratios. Post-mission X-ray analysis detected phyllosilicates, which indicates that examining beyond the VNIR (e.g., shortwave infrared, 1000-2500 nm) will enhance the detection of other minerals formed by aqueous processes. Despite the limited spectral range of VNIR point spectrometry utilized in the MARTE Mars drilling simulation project, ferric iron minerals could be identified in retrieved core material, and their distribution served to direct core subsampling for biological analysis.

Visible-near infrared point spectrometry of drill core samples from Río Tinto, Spain: results from the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) drilling exercise.

PubMed

Sutter, Brad; Brown, Adrian J; Stoker, Carol R

2008-10-01

Sampling of subsurface rock may be required to detect evidence of past biological activity on Mars. The Mars Astrobiology Research and Technology Experiment (MARTE) utilized the Río Tinto region, Spain, as a Mars analog site to test dry drilling technologies specific to Mars that retrieve subsurface rock for biological analysis. This work examines the usefulness of visible-near infrared (VNIR) (450-1000 nm) point spectrometry to characterize ferric iron minerals in core material retrieved during a simulated Mars drilling mission. VNIR spectrometry can indicate the presence of aqueously precipitated ferric iron minerals and, thus, determine whether biological analysis of retrieved rock is warranted. Core spectra obtained during the mission with T1 (893-897 nm) and T2 (644-652 nm) features indicate goethite-dominated samples, while relatively lower wavelength T1 (832-880 nm) features indicate hematite. Hematite/goethite molar ratios varied from 0 to 1.4, and within the 880-898 nm range, T1 features were used to estimate hematite/goethite molar ratios. Post-mission X-ray analysis detected phyllosilicates, which indicates that examining beyond the VNIR (e.g., shortwave infrared, 1000-2500 nm) will enhance the detection of other minerals formed by aqueous processes. Despite the limited spectral range of VNIR point spectrometry utilized in the MARTE Mars drilling simulation project, ferric iron minerals could be identified in retrieved core material, and their distribution served to direct core subsampling for biological analysis.

Micro X-ray CT imaging of pore-scale changes in unconsolidated sediment under confining pressure

NASA Astrophysics Data System (ADS)

Schindler, M.; Prasad, M.

2017-12-01

Micro X-ray computed tomography was used to image confining-pressure induced changes in a dry, unconsolidated quartz sand pack while simultaneously recording ultrasonic P-wave velocities. The experiments were performed under in-situ pressure of up to 4000 psi. The majority of digital rock physics studies rely on micro CT images obtained under ambient pressure and temperature conditions although effective rock properties strongly depend on in situ conditions. Goal of this work is to be able to obtain micro CT images of rock samples while pore and confining pressure is applied. Simultaneously we recorded ultrasonic P-wave velocities. The combination of imaging and velocity measurements provides insight in pore-scale changes in the rock and their influence on elastic properties. We visually observed a reduction in porosity by more than a third of the initial value as well as extensive grain damage, changes in pore and grain size distribution and an increase in contact number and contact radius with increasing confining pressure. An increase in measured ultrasonic P-wave velocities with increasing pressure was observed. We used porosity, contact number and contact radius obtained from micro CT images to model P-wave velocity with the contact-radius model by Bachrach et al. (1998). Our observations showed that the frame of unconsolidated sediments is significantly altered starting at pressures of only 1000 psi. This finding indicates that common assumptions in rock physics models (the solid frame remains unchanged) are violated for unconsolidated sediments. The effects on the solid frame should be taken into account when modeling the pressure dependence of elastic rock properties.

Direct observations of rock moisture, a hidden component of the hydrologic cycle

NASA Astrophysics Data System (ADS)

Rempe, Daniella M.; Dietrich, William E.

2018-03-01

Recent theory and field observations suggest that a systematically varying weathering zone, that can be tens of meters thick, commonly develops in the bedrock underlying hillslopes. Weathering turns otherwise poorly conductive bedrock into a dynamic water storage reservoir. Infiltrating precipitation typically will pass through unsaturated weathered bedrock before reaching groundwater and running off to streams. This invisible and difficult to access unsaturated zone is virtually unexplored compared with the surface soil mantle. We have proposed the term “rock moisture” to describe the exchangeable water stored in the unsaturated zone in weathered bedrock, purposely choosing a term parallel to, but distinct from, soil moisture, because weathered bedrock is a distinctly different material that is distributed across landscapes independently of soil thickness. Here, we report a multiyear intensive campaign of quantifying rock moisture across a hillslope underlain by a thick weathered bedrock zone using repeat neutron probe measurements in a suite of boreholes. Rock moisture storage accumulates in the wet season, reaches a characteristic upper value, and rapidly passes any additional rainfall downward to groundwater. Hence, rock moisture storage mediates the initiation and magnitude of recharge and runoff. In the dry season, rock moisture storage is gradually depleted by trees for transpiration, leading to a common lower value at the end of the dry season. Up to 27% of the annual rainfall is seasonally stored as rock moisture. Significant rock moisture storage is likely common, and yet it is missing from hydrologic and land-surface models used to predict regional and global climate.

Permeability of gypsum samples dehydrated in air

NASA Astrophysics Data System (ADS)

Milsch, Harald; Priegnitz, Mike; Blöcher, Guido

2011-09-01

We report on changes in rock permeability induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air (dry) for up to 800 h at ambient pressure and temperatures between 378 and 423 K. Subsequently, the reaction kinetics, so induced changes in porosity, and the concurrent evolution of sample permeability were constrained. Weighing the heated samples in predefined time intervals yielded the reaction progress where the stoichiometric mass balance indicated an ultimate and complete dehydration to anhydrite regardless of temperature. Porosity showed to continuously increase with reaction progress from approximately 2% to 30%, whilst the initial bulk volume remained unchanged. Within these limits permeability significantly increased with porosity by almost three orders of magnitude from approximately 7 × 10-19 m2 to 3 × 10-16 m2. We show that - when mechanical and hydraulic feedbacks can be excluded - permeability, reaction progress, and porosity are related unequivocally.

The influence of carbonates in parent rocks on the biological properties of mountain soils of the Northwest Caucasus region

NASA Astrophysics Data System (ADS)

Kazeev, K. Sh.; Kutrovskii, M. A.; Dadenko, E. V.; Vezdeneeva, L. S.; Kolesnikov, S. I.; Val'kov, V. F.

2012-03-01

The biological activity of different subtypes of soddy-calcareous soils (rendzinas) of the Northwest Caucasus region was studied. In the Novorossiisk-Abrau-Dyurso region (dry subtropics), typical soddy-calcareous soils with the high content of carbonates predominate; in the more humid conditions of the Lagonaki Plateau (Republic of Adygeya), leached soddy-calcareous soils carbonate-free down to the parent rock are spread. The number of microarthropods, the populations of fungi and bacteria, and the enzyme activity (catalase, dehydrogenase, and invertase) testify that the biological activity of these soils significantly differs. In the typical soddy-calcareous soils of the dry subtropics, the content of carbonates does not affect the characteristics mentioned; in the more humid conditions of the West Caucasus region, the presence of carbonates in the parent rocks intensifies the biological activity of the soddy-calcareous soils.

Earth observations taken from shuttle orbiter Discovery on STS-70 mission

NASA Image and Video Library

1995-07-21

STS070-717-011 (13-22 JULY 1995) --- Volcanic landscapes with a thin dusting of snow appear in this near-vertical view of the dry, high spine of the Andes Mountains at around 28 degrees south latitude. Strong westerly winds (from left) have blown the snow off the highest volcanic peaks (center and bottom): many of these peaks rise higher than 20,000 feet. A small, dry lake appears top right, the white color derived from salts. The border between Argentina and Chile winds from volcano to volcano and passes just left of the small blue lake (left center). Black lava flows can be detected bottom right. The larger area of brown-pink rocks (bottom rock) is also an area of volcanic rocks, of a type known as ash flow tuffs which are violently extruded, often in volumes measured in cubic kilometers.

77 FR 9914 - Combined Notice of Filings #2

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-21

... Power, LLC, Dry Lake Wind Power II LLC, Elk River Windfarm, LLC, Elm Creek Wind, LLC, Elm Creek Wind II LLC, Farmers City Wind, LLC, Flat Rock Windpower LLC, Flat Rock Windpower II LLC, Flying Cloud Power Partners, LLC, Hardscrabble Wind Power LLC, Hay Canyon Wind LLC, Juniper Canyon Wind Power LLC, Klamath...

78 FR 8121 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-05

... Green Holdings LLC, Dillon Wind LLC, Dry Lake Wind Power, LLC, Dry Lake Wind Power II LLC, Elk River..., Flat Rock Windpower II LLC, Flying Cloud Power Partners, LLC, Groton Wind, LLC, Hardscrabble Wind Power LLC, Hay Canyon Wind LLC, Juniper Canyon Wind Power LLC, Klamath [[Page 8122

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2011-08-02

... Holdings LLC, Dillon Wind LLC, Dry Lake Wind Power, LLC, Dry Lake Wind Power II LLC, Elk River Windfarm... Rock Windpower II LLC, Flying Cloud Power Partners, LLC, Hardscrabble Wind Power LLC, Hay Canyon Wind LLC, Juniper Canyon Wind Power LLC, Klamath Energy LLC, Klamath Generation LLC, Klondike Wind Power...

Assessment of brittleness and empirical correlations between physical and mechanical parameters of the Asmari limestone in Khersan 2 dam site, in southwest of Iran

NASA Astrophysics Data System (ADS)

Lashkaripour, Gholam Reza; Rastegarnia, Ahmad; Ghafoori, Mohammad

2018-02-01

The determination of brittleness and geomechanical parameters, especially uniaxial compressive strength (UCS) and Young's modulus (ES) of rocks are needed for the design of different rock engineering applications. Evaluation of these parameters are time-consuming processes, tedious, expensive and require well-prepared rock cores. Therefore, compressional wave velocity (Vp) and index parameters such as point load index and porosity are often used to predict the properties of rocks. In this paper, brittleness and other properties, physical and mechanical in type, of 56 Asmari limestones in dry and saturated conditions were analyzed. The rock samples were collected from Khersan 2 dam site. This dam with the height of 240 m is being constructed and located in the Zagros Mountain, in the southwest of Iran. The bedrock and abutments of the dam site consist of Asemari and Gachsaran Formations. In this paper, a practical relation for predicting brittleness and some relations between mechanical and index parameters of the Asmari limestone were established. The presented equation for predicting brittleness based on UCS, Brazilian tensile strength and Vp had high accuracy. Moreover, results showed that the brittleness estimation based on B3 concept (the ratio of multiply compressive strength in tensile strength divided 2) had more accuracy as compared to the B2 (the ratio of compressive strength minus tensile strength to compressive strength plus tensile strength) and B1 (the ratio of compressive strength to tensile strength) concepts.

Biological Sterilization of Returned Mars Samples

NASA Technical Reports Server (NTRS)

Allen, C. C.; Albert, F. G.; Combie, J.; Bodnar, R. J.; Hamilton, V. E.; Jolliff, B. L.; Kuebler, K.; Wang, A.; Lindstrom, D. J.; Morris, P. A.

1999-01-01

Martian rock and soil, collected by robotic spacecraft, will be returned to terrestrial laboratories early in the next century. Current plans call for the samples to be immediately placed into biological containment and tested for signs of present or past life and biological hazards. It is recommended that "Controlled distribution of unsterilized materials from Mars should occur only if rigorous analyses determine that the materials do not constitute a biological hazard. If any portion of the sample is removed from containment prior to completion of these analyses it should first be sterilized." While sterilization of Mars samples may not be required, an acceptable method must be available before the samples are returned to Earth. The sterilization method should be capable of destroying a wide range of organisms with minimal effects on the geologic samples. A variety of biological sterilization techniques and materials are currently in use, including dry heat, high pressure steam, gases, plasmas and ionizing radiation. Gamma radiation is routinely used to inactivate viruses and destroy bacteria in medical research. Many commercial sterilizers use Co-60 , which emits gamma photons of 1.17 and 1.33 MeV. Absorbed doses of approximately 1 Mrad (10(exp 8) ergs/g) destroy most bacteria. This study investigates the effects of lethal doses of Co-60 gamma radiation on materials similar to those anticipated to be returned from Mars. The goals are to determine the gamma dose required to kill microorganisms in rock and soil samples and to determine the effects of gamma sterilization on the samples' isotopic, chemical and physical properties. Additional information is contained in the original extended abstract.

Effect of processing on the microflora of Norwegian seaweed meal, with observations on Sporendonema minutum (Hoye) Frank and Hess.

PubMed

Sieburth, J M; Jensen, A

1967-07-01

Meal from the brown seaweed Ascophyllum nodosum (L.) Le Jol. is mainly used as an animal feed supplement. Since moist weed often develops a marked mold growth and since little was known about the microflora of seaweed meal, a cultural procedure was developed to enumerate the populations of bacteria, yeasts, and molds of seaweed meals manufactured by different drying processes. The microflora could be supported by a variety of media varying in levels of nutrition and in the source and concentration of salts. Fresh weed contained less than 10(3) bacteria and less than 10(2) yeasts and molds per g (dry weight). The type and extent of microbial populations in seaweed meal appeared to be dependent upon the method of seaweed drying. Rotary drum-drying at temperatures decreasing from 800 to 80 C maintained or reduced the microbial populations to 10(3) organisms per g (dry weight). Although meals with high nutritional quality can be obtained with warm air- or rock-dried weed, these conditions can also permit bacterial and mold development. Extended rock-drying in variable weather conditions and prolonged storage of moist weed, both of which decrease the nutritional quality, also lead to high bacterial numbers and to a marked development of the halophilic brown mold Sporendonema minutum which attained populations of 10(8) viable spores per g of dried weed. A poultry diet containing 5% badly molded weed had no apparent toxic or growth-depressing effect when fed to chicks.

High-velocity frictional properties of Alpine Fault rocks: Mechanical data, microstructural analysis, and implications for rupture propagation

NASA Astrophysics Data System (ADS)

Boulton, Carolyn; Yao, Lu; Faulkner, Daniel R.; Townend, John; Toy, Virginia G.; Sutherland, Rupert; Ma, Shengli; Shimamoto, Toshihiko

2017-04-01

The Alpine Fault in New Zealand is a major plate-bounding structure that typically slips in ∼M8 earthquakes every c. 330 years. To investigate the near-surface, high-velocity frictional behavior of surface- and borehole-derived Alpine Fault gouges and cataclasites, twenty-one rotary shear experiments were conducted at 1 MPa normal stress and 1 m/s equivalent slip velocity under both room-dry and water-saturated (wet) conditions. In the room-dry experiments, the peak friction coefficient (μp = τp/σn) of Alpine Fault cataclasites and fault gouges was consistently high (mean μp = 0.67 ± 0.07). In the wet experiments, the fault gouge peak friction coefficients were lower (mean μp = 0.20 ± 0.12) than the cataclasite peak friction coefficients (mean μp = 0.64 ± 0.04). All fault rocks exhibited very low steady-state friction coefficients (μss) (room-dry experiments mean μss = 0.16 ± 0.05; wet experiments mean μss = 0.09 ± 0.04). Of all the experiments performed, six experiments conducted on wet smectite-bearing principal slip zone (PSZ) fault gouges yielded the lowest peak friction coefficients (μp = 0.10-0.20), the lowest steady-state friction coefficients (μss = 0.03-0.09), and, commonly, the lowest specific fracture energy values (EG = 0.01-0.69 MJ/m2). Microstructures produced during room-dry and wet experiments on a smectite-bearing PSZ fault gouge were compared with microstructures in the same material recovered from the Deep Fault Drilling Project (DFDP-1) drill cores. The near-absence of localized shear bands with a strong crystallographic preferred orientation in the natural samples most resembles microstructures formed during wet experiments. Mechanical data and microstructural observations suggest that Alpine Fault ruptures propagate preferentially through water-saturated smectite-bearing fault gouges that exhibit low peak and steady-state friction coefficients.

Climate Change on Mars: From Wet in the Noachian at Meridiani to Dry and Desiccating in the Hesperian/Amazonian Plains of Gusev

NASA Astrophysics Data System (ADS)

Golombek, M.

2004-12-01

Sedimentary dirty evaporites in Meridiani Planum were deposited in salt-water playas or sabkhas in the Noachian, roughly coeval with a variety of geomorphic indicators (valley networks, degraded craters and highly eroded terrain) of a possible early warmer and wetter environment. In contrast, the cratered plains of Gusev that Spirit has traversed (exclusive of the Columbia Hills) have been dominated by impact and eolian processes and a gradation history that argues for a dry and desiccating environment since the Late Hesperian. The Late Hesperian/Early Amazonian cratered plains of Gusev crater are generally low relief moderately rocky plains dominated by hollows, which appear to be craters filled with soil. Rocks are generally angular basalt fragments in an unconsolidated >10 m thick regolith of likely impact origin. Eolian bedforms appear to be presently inactive ripples and no active sand dunes have been identified. Moderate localized surface deflation of 5 to 60 cm is indicated by two-toned rocks with a redder patination along the base, ventifacts that originate from a common horizon above the soil (suggesting that the lower part of the rock was shielded), rocks that appear to be perched on top of other rocks, and some undercut rocks, in which the soil has been removed from their bases. The observed gradation and deflation of ejected fines and deposition in craters to form hollows thus provides a measure of the rate of erosion (average vertical removal of material per unit time), which yields extremely slow erosion rates of order 0.1 nm/yr comparable to those estimated at the Mars Pathfinder ( ˜0.01 nm/yr) and Viking Lander 1 ( ˜1 nm/yr) sites and argues that a dry and desiccating environment similar to today's has been active throughout the Hesperian and Amazonian (since ˜3.7 Ga). By comparison, erosion rates estimated from changes in Noachian age crater distributions and shapes are 3-5 orders of magnitude higher and comparable to slow denudation rates on the Earth (>5 micron/yr) that are dominated by liquid water. The erosion rates from Gusev as well as those from Viking 1 and Pathfinder strongly limit this warmer and wetter period (possibly recorded in the Meridiani evaporites) to the Noachian, pre-3.7 Ga and a dry and desiccating climate since.

Estimates of natural ground-water discharge and characterization of water quality in Dry Valley, Washoe County, West-Central Nevada, 2002-2003

USGS Publications Warehouse

Berger, David L.; Maurer, Douglas K.; Lopes, Thomas J.; Halford, Keith J.

2004-01-01

The Dry Valley Hydrographic Area is being considered as a potential source area for additional water supplies for the Reno-Sparks area, which is about 25 miles south of Dry Valley. Current estimates of annual ground-water recharge to Dry Valley have a considerable range. In undeveloped valleys, such as Dry Valley, long-term ground-water discharge can be assumed the same as long-term ground-water recharge. Because estimating ground-water discharge has more certainty than estimating ground-water recharge from precipitation, the U.S. Geological Survey, in cooperation with Washoe County, began a three-year study to re-evaluate the ground-water resources by estimating natural ground-water discharge and characterize ground-water quality in Dry Valley. In Dry Valley, natural ground-water discharge occurs as subsurface outflow and by ground-water evapotranspiration. The amount of subsurface outflow from the upper part of Dry Valley to Winnemucca and Honey Lake Valleys likely is small. Subsurface outflow from Dry Valley westward to Long Valley, California was estimated using Darcy's Law. Analysis of two aquifer tests show the transmissivity of poorly sorted sediments near the western side of Dry Valley is 1,200 to 1,500 square feet per day. The width of unconsolidated sediments is about 4,000 feet between exposures of tuffaceous deposits along the State line, and decreases to about 1,500 feet (0.5 mile) west of the State line. The hydraulic gradient east and west of the State line ranges from 0.003 to 0.005 foot per foot. Using these values, subsurface outflow to Long Valley is estimated to be 50 to 250 acre-feet per year. Areas of ground-water evapotranspiration were field mapped and partitioned into zones of plant cover using relations derived from Landsat imagery acquired July 8, 2002. Evapotranspiration rates for each plant-cover zone were multiplied by the corresponding area and summed to estimate annual ground-water evapotranspiration. About 640 to 790 acre-feet per year of ground water is lost to evapotranspiration in Dry Valley. Combining subsurface-outflow estimates with ground-water evapotranspiration estimates, total natural ground-water discharge from Dry Valley ranges from a minimum of about 700 acre-feet to a maximum of about 1,000 acre-feet annually. Water quality in Dry Valley generally is good and primary drinking-water standards were not exceeded in any samples collected. The secondary standard for manganese was exceeded in three ground-water samples. One spring sample and two surface-water samples exceeded the secondary standard for pH. Dry Valley has two primary types of water chemistry that are distinguishable by cation ratios and related to the two volcanic-rock units that make up much of the surrounding mountains. In addition, two secondary types of water chemistry appear to have evolved by evaporation of the primary water types. Ground water near the State line appears to be an equal mixture of the two primary water chemistries and has as an isotopic characteristic similar to evaporated surface water.

5. Aerial view (altitude 5,000 ft.) looking southeast showing Dry ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Aerial view (altitude 5,000 ft.) looking southeast showing Dry Dock No. 4. completed (top center). Note major expansion of land mass to south of Dry Dock No. 4 resulting from placement of excavated soils and rock prior to and during construction (8/3/43). Photographer: Mr. Rudnick, PHoM 2/C. - Hunters Point Naval Shipyard, Drydock No. 4, East terminus of Palou Avenue, San Francisco, San Francisco County, CA

A Preliminary Study on Rock Bed Heat Storage from Biomass Combustion for Rice Drying

NASA Astrophysics Data System (ADS)

Nelwan, L. O.; Wulandani, D.; Subrata, I. D. M.

2018-05-01

One of the main constraints of biomass fuel utilization in a small scale rice drying system is the operating difficulties related to the adjustment of combustion/feeding rate. Use of thermal storage may reduce the problem since combustion operation can be accomplished in a much shorter time and then the use of heat can be regulated by simply adjusting the air flow. An integrated biomass furnace-rock bed thermal storage with a storage volume of 540 L was designed and tested. There were four experiments conducted in this study. Charging was performed within 1-2 hours with a combustion rate of 11.5-15.5 kg/h. In discharging process, the mixing of air passing through the rock bed and ambient air were regulated by valves. Without adjusting the valve during the discharging process, air temperature increased up to 80°C, which is not suitable for rice batch drying process. Charging with sufficiently high combustion rate (14 kg/h) within 1 hour continued by adjusting the valve during discharging process below 60°C increased the discharge-charge time ratio (DCTR) up to 5.33 at average air temperature of 49°C and ambient temperature of 33°C.The efficiency of heat discharging was ranged from 34.5 to 45.8%. From the simulation, as much as 156.8-268.8 kg of rice was able to be dried by the discharging conditions.

Landscape in a Lacquer Box

ERIC Educational Resources Information Center

Savage, Martha

2010-01-01

A symbolic dry landscape garden of Eastern origin holds a special fascination for the author's middle-school students, which is why the author chose to create a project exploring this view of nature. A dry landscape garden, or "karesansui," is an arrangement of rocks, worn by nature and surrounded by a "sea" of sand, raked into patterns…

Estimation of Dry Fracture Weakness, Porosity, and Fluid Modulus Using Observable Seismic Reflection Data in a Gas-Bearing Reservoir

NASA Astrophysics Data System (ADS)

Chen, Huaizhen; Zhang, Guangzhi

2017-05-01

Fracture detection and fluid identification are important tasks for a fractured reservoir characterization. Our goal is to demonstrate a direct approach to utilize azimuthal seismic data to estimate fluid bulk modulus, porosity, and dry fracture weaknesses, which decreases the uncertainty of fluid identification. Combining Gassmann's (Vier. der Natur. Gesellschaft Zürich 96:1-23, 1951) equations and linear-slip model, we first establish new simplified expressions of stiffness parameters for a gas-bearing saturated fractured rock with low porosity and small fracture density, and then we derive a novel PP-wave reflection coefficient in terms of dry background rock properties (P-wave and S-wave moduli, and density), fracture (dry fracture weaknesses), porosity, and fluid (fluid bulk modulus). A Bayesian Markov chain Monte Carlo nonlinear inversion method is proposed to estimate fluid bulk modulus, porosity, and fracture weaknesses directly from azimuthal seismic data. The inversion method yields reasonable estimates in the case of synthetic data containing a moderate noise and stable results on real data.

The characterization, mobility, and persistence of roaster-derived arsenic in soils at Giant Mine, NWT

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

Bromstad, Mackenzie J.; Wrye, Lori A.; Jamieson, Heather E.

Approximately 20,000 tonnes of arsenic (As)-bearing emissions from roasting gold (Au)-bearing arsenopyrite ore were aerially released from 1949 to 1999 at Giant Mine, near Yellowknife, Canada. Soil samples collected within 4 km of the former roaster from sites undisturbed by mining or other human activity contain up to 7700 mg/kg total As. Total As concentrations are highest within a few cm of the surface, and particularly enriched in soil pockets on rock outcrops. Scanning electron microscopy and synchrotron microanalysis show that roaster-derived arsenic trioxide (As2O3) has persisted in shallow soils in the area. Roaster-generated maghemite and hematite are also present.more » These anthropogenic forms of As are much more common in near-surface soils than natural As-bearing minerals. Comparison of the proportions of As, Sb, and Au concentrations in outcrop soil samples and historic As2O3-rich dust captured by emission controls suggest most of the roaster-derived As in soils at Giant was likely deposited before 1964. Topographic restriction by rock outcrops and a dry, cold climate likely contribute to the persistence of As2O3 in outcrop soils.« less

Investigation of Solar Radiation Properties at the Battleship Promontory Area, Antarctica

NASA Technical Reports Server (NTRS)

VanNortwick, Sara S.

2005-01-01

JPL scientists in January 2005 visited the unique Battleship Promontory Area of the Antarctic Dry Valleys at 76 deg. 54 min. S one of the few places on the Antarctic continent home to viable life. Cryptoendolithic microorganisms manage to survive on and inside rocks in Antarctica's harsh conditions of extreme dryness and cold that are not So different from the past and present conditions on Mars. We are investigating the physical properties of these biological creatures through analysis of optical spectra collected from a variety of rock samples over the deep UV, visible, and near-infrared regions with the intent of gaining key insights into the environmental factors that make such a habitat viable for life. The LabView programming environment is equipped with the tools necessary to create an interface to visualize, manipulate, and normalize extensive raw reflectance and corresponding incident spectral data. We are determining the meaning of the colors observed and their relationship to the ability to acquire energy and investigating differences between the photosynthetic processes in full sunlight and diffuse/shadow lighting. Comparisons between spectral data collected in the field and from returned samples in the lab validate the accuracy of our field collection methodology.

Microbial community composition and endolith colonization at an Arctic thermal spring are driven by calcite precipitation

USGS Publications Warehouse

Starke, Verena; Kirshtein, Julie; Fogel, Marilyn L.; Steele, Andrew

2013-01-01

Environmental conditions shape community composition. Arctic thermal springs provide an opportunity to study how environmental gradients can impose strong selective pressures on microbial communities and provide a continuum of niche opportunities. We use microscopic and molecular methods to conduct a survey of microbial community composition at Troll Springs on Svalbard, Norway, in the high Arctic. Microorganisms there exist under a wide range of environmental conditions: in warm water as periphyton, in moist granular materials, and in cold, dry rock as endoliths. Troll Springs has two distinct ecosystems, aquatic and terrestrial, together in close proximity, with different underlying environmental factors shaping each microbial community. Periphyton are entrapped during precipitation of calcium carbonate from the spring's waters, providing microbial populations that serve as precursors for the development of endolithic communities. This process differs from most endolith colonization, in which the rock predates the communities that colonize it. Community composition is modulated as environmental conditions change within the springs. At Troll, the aquatic environments show a small number of dominant operational taxonomic units (OTUs) that are specific to each sample. The terrestrial environments show a more even distribution of OTUs common to multiple samples.

Atmospheric Deposition of Heavy Metals in Soil Affected by Different Soil Uses of Southern Spain

NASA Astrophysics Data System (ADS)

Acosta, J. A.; Faz, A.; Martínez-Martínez, S.; Bech, J.

2009-04-01

Heavy metals are a natural constituent of rocks, sediments and soils. However, the heavy metal content of top soils is also dependent on other sources than weathering of the indigenous minerals; input from atmospheric deposition seems to be an important pathway. Atmospheric deposition is defined as the process by which atmospheric pollutants are transferred to terrestrial and aquatic surfaces and is commonly classified as either dry or wet. The interest in atmospheric deposition has increased over the past decade due to concerns about the effects of deposited materials on the environment. Dry deposition provides a significant mechanism for the removal of particles from the atmosphere and is an important pathway for the loading of heavy metals into the soil ecosystem. Within the last decade, an intensive effort has been made to determine the atmospheric heavy metal deposition in both urban and rural areas. The main objective of this study was to identification of atmospheric heavy metals deposition in soil affected by different soil uses. Study area is located in Murcia Province (southeast of Spain), in the surroundings of Murcia City. The climate is typically semiarid Mediterranean with an annual average temperature of 18°C and precipitation of 350 mm. In order to determine heavy metals atmospheric deposition a sampling at different depths (0-1 cm, 1-5 cm, 5-15 cm and 15-30 cm) was carried out in 7 sites including agricultural soils, two industrial areas and natural sites. The samples were taken to the laboratory where, dried, passed through a 2 mm sieve, and grinded. For the determination of the moisture the samples were weighed and oven dried at 105 °C for 24 h. The total amounts of metals (Pb, Cu, Pb, Zn, Cd, Mn, Ni and Cr) were determined by digesting the samples with nitric/perchoric acids and measuring with ICP-MS. Results showed that zinc contamination in some samples of industrial areas was detected, even this contamination reaches 30 cm depth; thus it is not possible to conclude that the actual contamination by zinc is due to atmospheric deposition or spill. However, some samples in this same area present lightly higher zinc concentration in topsoil than in subsoil indicating a cursory atmospheric deposition. Regarding to lead, one of the industrial areas showed a very active atmospheric deposition, with concentrations higher than 900 mg/kg in topsoil decreasing until less than 10 mg/kg to 30 cm depth. Oppositely, the lead concentration in natural soil is constant in the profile. On the other hand, the range of cadmium concentrations in the different depths of the profiles was, generally, low. Only one sample from the industrial area shows high concentration in the first centimetre of soil, decreasing quickly with the depth, supporting the hypothesis that the atmospheric deposition is the main pathway of cadmium contamination. Studding the copper concentration, only in agricultural soil atmospheric deposition is observed, probably due to application of pesticides. Oppositely to the rest of metals, manganese increases its concentration with the depth in natural soil, probably due to that the parent material (metamorphic rock) is rich in this metal. In the case of chromium has not been detected atmospheric deposition in any sampling point. Finally, only one sample located at the industrial area, nickel concentration shows a higher level in topsoil than subsoil, indicating atmospheric deposition. Acknowledgements: to "Fundación Séneca" of "Comunidad Autónoma de Murcia" for its financial support

Core Cutting Test with Vertical Rock Cutting Rig (VRCR)

NASA Astrophysics Data System (ADS)

Yasar, Serdar; Osman Yilmaz, Ali

2017-12-01

Roadheaders are frequently used machines in mining and tunnelling, and performance prediction of roadheaders is important for project economics and stability. Several methods were proposed so far for this purpose and, rock cutting tests are the best choice. Rock cutting tests are generally divided into two groups which are namely, full scale rock cutting tests and small scale rock cutting tests. These two tests have some superiorities and deficiencies over themselves. However, in many cases, where rock sampling becomes problematic, small scale rock cutting test (core cutting test) is preferred for performance prediction, since small block samples and core samples can be conducted to rock cutting testing. Common problem for rock cutting tests are that they can be found in very limited research centres. In this study, a new mobile rock cutting testing equipment, vertical rock cutting rig (VRCR) was introduced. Standard testing procedure was conducted on seven rock samples which were the part of a former study on cutting rocks with another small scale rock cutting test. Results showed that core cutting test can be realized successfully with VRCR with the validation of paired samples t-test.

Climate change from wet to dry at the Mars Exploration Rover landing sites

NASA Astrophysics Data System (ADS)

Golombek, M.; Athena Science Team

Sedimentary dirty evaporites in Meridiani Planum were deposited in salt-water playas or sabkhas in the Noachian and highly water altered rocks in the Columbia Hills of Gusev crater formed at a time when a variety of geomorphic indicators on Mars valley networks degraded craters highly eroded terrain and layered sedimentary deposits indicate a possible early warmer and wetter environment In contrast the cratered plains of Gusev that Spirit has traversed exclusive of the Columbia Hills have been dominated by impact and eolian processes and a gradation history that argues for a dry and desiccating environment since the Late Hesperian The Late Hesperian Early Amazonian cratered plains of Gusev crater are generally low relief moderately rocky plains dominated by hollows which appear to be craters filled with soil Rocks are generally angular basalt fragments in an unconsolidated 10 m thick regolith of likely impact origin Eolian bedforms appear to be presently inactive ripples and no active sand dunes have been identified Moderate localized surface deflation of 5 to 25 cm is indicated by two-toned rocks with a redder patination along the base ventifacts that originate from a common horizon above the soil suggesting that the lower part of the rock was shielded rocks that appear to be perched on top of other rocks and some undercut rocks in which the soil has been removed from their bases The observed gradation and deflation of ejected fines and deposition in craters to form hollows thus provides a measure of the rate of erosion average vertical removal

Direct laboratory observation of fluid distribution and its influence on acoustic properties of patchy saturated rocks

NASA Astrophysics Data System (ADS)

Lebedev, M.; Clennell, B.; Pervukhina, M.; Shulakova, V.; Mueller, T.; Gurevich, B.

2009-04-01

Porous rocks in hydrocarbon reservoirs are often saturated with a mixture of two or more fluids. Interpretation of exploration seismograms requires understanding of the relationship between distribution of the fluids patches and acoustic properties of rocks. The sizes of patches as well as their distribution affect significantly the seismic response. If the size of the fluid patch is smaller than the diffusion wavelength then pressure equilibration is achieved and the bulk modulus of the rock saturated with a mixture is defined by the Gassmann equations (Gassmann, 1951) with the saturation-weighted average of the fluid bulk modulus given by Wood's law (Wood, 1955, Mavko et al., 1998). If the fluid patch size is much larger than the diffusion wavelength then there is no pressure communication between different patches. In this case, fluid-flow effects can be neglected and the overall rock may be considered equivalent to an elastic composite material consisting of homogeneous parts whose properties are given by Gassmann theory with Hill's equation for the bulk modulus (Hill, 1963, Mavko et al., 1998). At intermediate values of fluid saturation the velocity-saturation relationship is significantly affected by the fluid patch distribution. In order to get an improved understanding of factors influencing the patch distribution and the resulting seismic wave response we performed simultaneous measurements of P-wave velocities and rock sample CT imaging. The CT imaging allows us to map the fluid distribution inside rock sample during saturation (water imbibition). We compare the experimental results with theoretical predictions. In this paper we will present results of simultaneous measurements of longitudinal wave velocities and imaging mapping of fluid distribution inside rock sample during sample saturation. We will report results of two kinds of experiments: "dynamic" and "quasi static" saturation. In both experiments Casino Cores Otway Basin sandstone, Australia core samples (38 mm in diameter, approximately 60 mm long) were dried in oven under reduced pressure. In dynamic saturation experiments, samples were jacketed in the experimental cell, made from transparent for X-radiation material (PMMA). Distillate water was injected into the sample from the one side. Fluid distribution in such "dynamic" experiment: both spatial and time dependant was measured using X-ray Computer Tomograph (CT) with resolution 0.2 x 0.2 x 1 mm3. Velocities (Vp, and Vs) at ultrasonic frequency of 1 MHz, were measured in the direction perpendicular to initial direction of the fluid flow injection. Sample saturation was estimated from the CT results. In "quasi static" experiments samples were saturated during long period of time (over 2 weeks) to achieve uniform distribution of liquid inside the sample. Saturation was determined by measurement of the weight of water fraction. All experiments were performed at laboratory environments at temperature 25 C. Ultrasonic velocities and fluid saturations were measured simultaneously during water injection into sandstone core samples. The experimental results obtained on low-permeability samples show that at low saturation values the velocity-saturation dependence can be described by the Gassmann-Wood relationship. However, with increasing saturation a sharp increase of P-wave velocity is observed, eventually approaching the Gassmann-Hill relationship. We connect the characteristics of the transition behavior of the velocity-saturation relationships to the increasing size of the patches inside the rock sample. In particular, we show that for relatively large fluid injection rate this transition occurs at smaller degrees of saturation as compared with high injection rate. We model the experimental data using the so-called White model (Toms 2007) that assumes fluid patch distribution as a periodic assemblage of concentric spheres. We can observe reasonable agreement between experimental results and theoretical predictions of White's model. The results illustrate the non-unique relationships between saturation and velocity in sandstones dependent on texture and fluid displacement history: fuller understanding of these phenomena is needed for accurate assessment of time lapse seismic measurements, be they for oil and gas recovery or for CO2 disposal purposes. Gassmann, F., 1951, Elastic waves through a packing of spheres. Geophysics 16, 673-685; Mavko, G., T. Mukerji, and J. Dvorkin, 1998, The Rock Physics Handbook: Tools for seismic analysis in porous media: Cambridge University Press. Wood, A. W., 1955, A Textbook of Sound, The MacMillan Co., New York, 360 pp. Hill, R., 1963, Elastic properties of reinforced solids: some theoretical principles. J. Mech. Phys. Solids, 11, 357-372. Hill, R., 1952, The elastic behavior of crystalline aggregates. Proc. Physical Soc., London, A65, 349-354. J. Toms, T.M. Mueller, B. Gurevich, 2007 Seismic attenuation in porous rocks with random patchy saturation. Geophysical Prospecting, 55, 671-678.

Geo-environmetal characterization of dry riverbeds affected by mine tailings in the Mazarrón district, Murcia (Spain)

NASA Astrophysics Data System (ADS)

Martín-Crespo, Tomás.; Gómez-Ortiz, David; Martínez-Pagán, Pedro; Martín-Velázquez, Silvia; de Ignacio, Cristina; Lillo, Javier; Faz, Angel

2010-05-01

Mine tailings constitute an environmental issue of public concern because they represent accumulations and emission sources of heavy metals and acid mine drainage by sulphide oxidation. In this work, two geophysical methods, electrical resistivity tomography (ERT) and ground-penetrating radar (GPR), as well as mineralogical and geochemical techniques have been used in order to obtain a geo-environmental characterization of two dry riverbeds in a mining district. The abandoned San Cristóbal and Los Perules mining group (Mazarrón, Murcia) has generated a huge amount of sludge from the Ag, Pb and Zn extraction operations. These tailings were piled up in ponds or directly dumped to the San Cristóbal dry riverbed located at the mining site, and Las Moreras dry riverbed, where San Cristóbal flows into a few meters downstream. Furthermore, Las Moreras watercourse flows into the Mediterranean Sea five kilometres downstream. Samples from two boreholes have been analyzed in order to obtain thickness, mineralogical and chemical composition of tailings and watercourse sedimentary materials affected by them. San Cristóbal sampling point shows a thickness of 3,5 m of mine tailings, 2 m of sedimentary materials, and the in situ volcanic rocks to 5,5 m depth. Las Moreras site shows a thickness of 2 m of a mine tailings deposit, 4 m of sedimentary materials, and the in situ metamorphic rocks 6 m depth. In both sites, significant amounts of pyrite (15-20 wt %), sphalerite (10-15 wt %) and galena (5-10 wt %) have been determined, and secondary oxides (hematite) and sulphates (gypsum, jarosite) minerals have been also identified. Ag, As, Cd, Co, Cu, Sb, V, Pb and Zn contents are also significant in all studied samples from tailings samples, and acid mine drainage has been clearly detected affecting the San Cristóbal dry riverbed. Regarding the alluvial materials from the riverbeds, pyrite, sphalerite and galena have been only identified in the San Cristóbal sampling point, probably due to its location at the mining site. Furthermore, heavy metal content of both dry riverbeds show significant amounts of Ag, As, Cu, Sb, Pb, V and Zn, indicating an important process of contamination from the surficial tailings to the natural sediments and watercourses. Water from Las Moreras riverbed has also been analysed. Its pH is about 8 and it exhibit higher values in conductivity and TDS, together with the concentrations of major metallic ions, mainly Cu, Ni, Fe and Zn, most of them beyond the established limits for this kind of natural waters. ERT and GPR techniques have provided estimations of both thickness and internal structure of the dry riverbeds infilling. For San Cristóbal site, ERT indicates a ~6 m thick sedimentary sequence, in good agreement with borehole data. An upper unit of 30 ohm.m extending up to 1.5 m depth, and a lower unit of resistivity values lower than 5 ohm.m up to 6 m depth can be distinguished. The first unit corresponds to upper part of the tailing, characterized by sand texture, whereas the lower one corresponds to tailing with silty-clay texture and sedimentary material with high metal contents. For Las Moreras site a 2 m thick upper unit of low (< 5 ohm-m) resistivity values and a 4 m thick lower one of ~20-30 ohm.m are distinguished, in good agreement with the surficial tailings and lower sedimentary materials obtained in the borehole. Joint application of geophysical and geochemical techniques has revealed itself as very useful for obtaining a complete characterization of abandoned mine deposits, previously to a future reclamation of these dangerous tailings.

X-ray microtomography analysis of soil structure deformation caused by centrifugation

NASA Astrophysics Data System (ADS)

Schlüter, Steffen; Leuther, Frederic; Vogler, Steffen; Vogel, Hans-Jörg

2016-04-01

Centrifugation provides a fast method to measure soil water retention curves over a wide moisture range. However, deformation of soil structure may occur at high angular velocities in the centrifuge. The objective of this study was to capture these changes in soil structure with X-ray microtomography and to measure local deformations via digital volume correlation. Two samples were investigated that differ in texture and rock content. A detailed analysis of the pore space reveals an interplay between shrinkage due to drying and soil compaction due to compression. Macroporosity increases at moderate angular velocity because of crack formation due to moisture release. At higher angular velocities, corresponding to capillary pressure of <-100kPa, macroporosity decreases again because of structure deformation due to compression. While volume changes due to swelling clay minerals are immanent to any drying process, the compaction of soil is a specific drawback of the centrifugation method. A new protocol for digital volume correlation was developed to analyze the spatial heterogeneity of deformation. In both samples the displacement of soil constituents is highest in the top part of the sample and exhibits high lateral variability explained by the spatial distribution of macropores in the sample. Centrifugation should therefore only be applied after the completion of all other hydraulic or thermal experiments, or any other analysis that depends on the integrity of soil structure.

X-ray microtomography analysis of soil structure deformation caused by centrifugation

NASA Astrophysics Data System (ADS)

Schlüter, S.; Leuther, F.; Vogler, S.; Vogel, H.-J.

2016-01-01

Centrifugation provides a fast method to measure soil water retention curves over a wide moisture range. However, deformation of soil structure may occur at high angular velocities in the centrifuge. The objective of this study was to capture these changes in soil structure with X-ray microtomography and to measure local deformations via digital volume correlation. Two samples were investigated that differ in texture and rock content. A detailed analysis of the pore space reveals an interplay between shrinkage due to drying and soil compaction due to compression. Macroporosity increases at moderate angular velocity because of crack formation due to moisture release. At higher angular velocities, corresponding to capillary pressure of ψ < -100 kPa, macroporosity decreases again because of structure deformation due to compression. While volume changes due to swelling clay minerals are immanent in any drying process, the compaction of soil is a specific drawback of the centrifugation method. A new protocol for digital volume correlation was developed to analyze the spatial heterogeneity of deformation. In both samples the displacement of soil constituents is highest in the top part of the sample and exhibits high lateral variability explained by the spatial distribution of macropores in the sample. Centrifugation should therefore only be applied after the completion of all other hydraulic or thermal experiments, or any other analysis that depends on the integrity of soil structure.

Use of porosity to estimate hydraulic properties of volcanic tuffs

USGS Publications Warehouse

Flint, L.E.; Selker, J.S.

2003-01-01

Correlations of hydraulic properties with easily measured physical properties are useful for purposes of site characterization in heterogeneous sites. Approximately 600 samples of volcanic rocks from Yucca Mountain, Nevada, representing lithologies with a large range of hydraulic properties, were analyzed to develop correlations of effective porosity with saturated hydraulic conductivity and moisture-retention curve-fit parameters that relate to lithologies of varying depositional history and alteration processes. Effective porosity, ??e, defined as the porosity calculated using drying at a relative humidity of -70 MPa, is used in a generalized Kozeny-Carman equation to predict saturated hydraulic conductivity, Ks = b??en, where b and n are constants. The entire dataset has an R2 of 0.36. When samples are grouped according to general lithology, correlations result in an R2 of 0.71 for the crystallized/vitric samples, 0.24 for samples with mineral alteration, and 0.34 for samples with microfractures, thus increasing the predictive capability over that of the total dataset. Published by Elsevier Science Ltd.

Mitigation of water repellency in burned soils applying hydrophillic polymers

NASA Astrophysics Data System (ADS)

Neris, Jonay; de la Torre, Sara; Vidal-Vazquez, Eva; Lado, Marcos

2017-04-01

In this study, the effect of fire on water repellency was analyzed in soils from different parent materials, as well as the suitability of anionic polyacrylamide (PAM) to reduce water repellency in these soils. Samples were collected in four different sites where wildfires took place: two in the Canary Islands, with soils developed on volcanic materials, and two in Galicia (NW Spain), with soils developed on plutonic rocks. In Galicia, two soil samples were collected in each site, one in the burnt area and one in an adjacent unburnt area. In the Canary Islands, four samples were collected from each site, three inside the burnt area where the soils were affected by different fire intensities, and one in an unburnt adjacent area. Samples were air-dried and sieved by a 2-mm mesh sieve. Water repellency was measured using the Water Drop Penetration Time test. An amount of 10 g of soil was placed in a tray. Five drops of deionized water were place on the soil surface with a pipette, and the time for each drop to fully penetrate into the soil was recorded. PAM solution was applied to the burnt soils simulating a field application rate of 1gm-2. The polymer used was Superfloc A-110 (Kemira Water Solutions BV, Holland) with 1x107 Da molecular weigth and 15% hydrolysis. PAM was sprayed on the soil surface as solution with a concentration 0.2 g/L. After the application, the samples were dried and the WDPT test was performed. Three replicates for each treatment and soil were used, and the treatments included: dry soil, dry soil after a wetting treatment, dry PAM-treated soil. The results showed that water repellency was modified by fire differently in the various soils. In hydrophilic soils and soils with low water repellency, water repellency was increased after the action of fire. In soils with noticeable initial water repellency, this was reduced or eliminated after the fire. Wetting repellent soils caused a decrease in water repellency most probably because of the spatial redistribution of hydrophobic organic compounds that caused water repellency. The addition of PAM further reduced in all of the cases. The application of PAM could be an effective method for mitigation of water repellency in burnt soils.

Effect of Processing on the Microflora of Norwegian Seaweed Meal, with Observations on Sporendonema minutum (Høye) Frank and Hess

PubMed Central

Sieburth, John McN.; Jensen, Arne

1967-01-01

Meal from the brown seaweed Ascophyllum nodosum (L.) Le Jol. is mainly used as an animal feed supplement. Since moist weed often develops a marked mold growth and since little was known about the microflora of seaweed meal, a cultural procedure was developed to enumerate the populations of bacteria, yeasts, and molds of seaweed meals manufactured by different drying processes. The microflora could be supported by a variety of media varying in levels of nutrition and in the source and concentration of salts. Fresh weed contained less than 103 bacteria and less than 102 yeasts and molds per g (dry weight). The type and extent of microbial populations in seaweed meal appeared to be dependent upon the method of seaweed drying. Rotary drum-drying at temperatures decreasing from 800 to 80 C maintained or reduced the microbial populations to 103 organisms per g (dry weight). Although meals with high nutritional quality can be obtained with warm air- or rock-dried weed, these conditions can also permit bacterial and mold development. Extended rock-drying in variable weather conditions and prolonged storage of moist weed, both of which decrease the nutritional quality, also lead to high bacterial numbers and to a marked development of the halophilic brown mold Sporendonema minutum which attained populations of 108 viable spores per g of dried weed. A poultry diet containing 5% badly molded weed had no apparent toxic or growth-depressing effect when fed to chicks. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:6069160

Infrared reflectance spectra (4-12 micron) of lunar samples

NASA Technical Reports Server (NTRS)

Nash, Douglas B.

1991-01-01

Presented here are infrared reflectance spectra of a typical set of Apollo samples to illustrate spectral character in the mid-infrared (4 to 12 microns) of lunar materials and how the spectra varies among three main forms: soil, breccia, and igneous rocks. Reflectance data, to a close approximation, are the inverse of emission spectra; thus, for a given material the spectral reflectance (R) at any given wavelength is related to emission (E) by 1 - R equals E. Therefore, one can use reflectance spectra of lunar samples to predict how emission spectra of material on the lunar surface will appear to spectrometers on orbiting spacecraft or earthbound telescopes. Spectra were measured in the lab in dry air using a Fourier Transform Infrared spectrometer. Shown here is only the key portion (4 to 12 microns) of each spectrum relating to the principal spectral emission region for sunlit lunar materials and to where the most diagnostic spectral features occur.

Elastic Anisotropy of Basalt

NASA Astrophysics Data System (ADS)

Becker, K.; Shapiro, S.; Stanchits, S.; Dresen, G.; Kaselow, A.; Vinciguerra, S.

2005-12-01

Elastic properties of rocks are sensitive to changes of the in-situ stress and damage state. In particular, seismic velocities are strongly affected by stress-induced formation and deformation of cracks or shear-enhanced pore collapse. The effect of stress on seismic velocities as a result of pore space deformation in isotropic rock at isostatic compression may be expressed by the equation: A+K*P-B*exp (-D*P) (1), where P=Pc-Pp is the effective pressure, the pure difference between confining pressure and pore pressure. The parameter A, K, B and D describe material constants determined using experimental data. The physical meaning of the parameters is given by Shapiro (2003, in Geophysics Vol.68(Nr.2)). Parameter D is related to the stress sensitivity of the rock. A similar relation was derived by Shapiro and Kaselow (2005, in Geophysics in press) for weak anisotropic rocks under arbitrary load. They describe the stress dependent anisotropy in terms of Thomson's (1986, in Geophysics, Vol. 51(Nr.10)) anisotropy parameters ɛ and γ as a function of stress in the case of an initially isotropic rock: ɛ ∝ E2-E3, γ ∝ E3-E2 (2) with Ei=exp (D*Pi). The exponential terms Ei are controlled by the effective stress components Pi. To test this relation, we have conducted a series of triaxial compression tests on dry samples of initially isotropic Etnean Basalt in a servo-controlled MTS loading frame equipped with a pressure cell. Confining pressure was 60, 40 and 20 MPa. Samples were 5 cm in diameter and 10 cm in length. Elastic anisotropy was induced by axial compression of the samples through opening and growth of microcracks predominantly oriented parallel to the sample axis. Ultrasonic P- and S- wave velocities were monitored parallel and normal to the sample axis by an array of 20 piezoceramic transducers glued to the surface. Preamplified full waveform signals were stored in two 12 channel transient recorders. According to equation 2 the anisotropy parameters are linear functions of the stress exponents. In order to verify the linear dependence of ɛ and γ from the stress exponents, these exponents and the anisotropy parameters based on the measured velocities have been computed. Parameter D was found from fitting equation 1 to the experimental data. Our experimental results are in an excellent agreement with a linear relation between the exponential terms and the seismic anisotropy parameters as theoretically predicted by equation 2.

Rock pushing and sampling under rocks on Mars

USGS Publications Warehouse

Moore, H.J.; Liebes, S.; Crouch, D.S.; Clark, L.V.

1978-01-01

Viking Lander 2 acquired samples on Mars from beneath two rocks, where living organisms and organic molecules would be protected from ultraviolet radiation. Selection of rocks to be moved was based on scientific and engineering considerations, including rock size, rock shape, burial depth, and location in a sample field. Rock locations and topography were established using the computerized interactive video-stereophotogrammetric system and plotted on vertical profiles and in plan view. Sampler commands were developed and tested on Earth using a full-size lander and surface mock-up. The use of power by the sampler motor correlates with rock movements, which were by plowing, skidding, and rolling. Provenance of the samples was determined by measurements and interpretation of pictures and positions of the sampler arm. Analytical results demonstrate that the samples were, in fact, from beneath the rocks. Results from the Gas Chromatograph-Mass Spectrometer of the Molecular Analysis experiment and the Gas Exchange instrument of the Biology experiment indicate that more adsorbed(?) water occurs in samples under rocks than in samples exposed to the sun. This is consistent with terrestrial arid environments, where more moisture occurs in near-surface soil un- der rocks than in surrounding soil because the net heat flow is toward the soil beneath the rock and the rock cap inhibits evaporation. Inorganic analyses show that samples of soil from under the rocks have significantly less iron than soil exposed to the sun. The scientific significance of analyses of samples under the rocks is only partly evaluated, but some facts are clear. Detectable quantities of martian organic molecules were not found in the sample from under a rock by the Molecular Analysis experiment. The Biology experiments did not find definitive evidence for Earth-like living organisms in their sample. Significant amounts of adsorbed water may be present in the martian regolith. The response of the soil from under a rock to the aqueous nutrient in the Gas Exchange instrument indicates that adsorbed water and hydrates play an important role in the oxidation potential of the soil. The rock surfaces are strong, because they did not scratch, chip or spall when the sampler pushed them. Fresh surfaces of soil and the undersides of rocks were exposed so that they could be imaged in color. A ledge of soil adhered to one rock that tilted, showing that a crust forms near the surface of Mars. The reason for low amounts of iron in the sampIes from under the rocks is not known at this time.

Mapping potentialy asbestos-bearing rocks using imaging spectroscopy

USGS Publications Warehouse

Swayze, G.A.; Kokaly, R.F.; Higgins, C.T.; Clinkenbeard, J.P.; Clark, R.N.; Lowers, H.A.; Sutley, S.J.

2009-01-01

Rock and soil that may contain naturally occurring asbestos (NOA), a known human carcinogen, were mapped in the Sierra Nevada, California, using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) to determine if these materials could be uniquely identified with spectroscopy. Such information can be used to prepare or refine maps of areas that may contain minerals that can be asbestiform, such as serpentine and tremolite-actinolite, which were the focus of this study. Although thick vegetation can conceal underlying rock and soil, use of linear-mixture spectra calculated from spectra of dry grass and serpentine allowed detection of serpentine in some parts of the study area with up to ~80% dry-grass cover. Chaparral vegetation, which was dominantly, but not exclusively, found in areas underlain by serpentinized ultramafic rocks, was also mapped. Overall, field checking at 201 sites indicated highly accurate identification by AVIRIS of mineral (94%) and vegetation (89%) categories. Practical applications of AVIRIS to mapping areas that may contain NOA include locating roads that are surfaced with serpentine aggregate, identifying sites that may require enhanced dust control or other safety measures, and filling gaps in geologic mapping where field access is limited.

Microbial trace fossils in Antarctica and the search for evidence of early life on Mars

NASA Technical Reports Server (NTRS)

Friedmann, E. Imre; Friedmann, Roseli O.

1989-01-01

It is possible to hypothesize that, if microbial life evolved on early Mars, fossil remnants of these organisms may be preserved on the surface. However, the cooling and drying of Mars probably resembled a cold desert and such an environment is not suitable for the process of fossilization. The frigid Ross Desert of Antarctica is probably the closest terrestrial analog to conditions that may have prevailed on the surface of the cooling and drying Mars. In this desert, cryptoendolithic microbial communities live in the airspaces of porous rocks, the last habitable niche in a hostile outside environment. The organisms produce characteristic chemical and physical changes in the rock substrate. Environmental changes (deterioration of conditions) may result in the death of the community. Although no cellular structures are fossilized, the conspicuous changes in the rock substrate are preserved as trace fossils. Likewise, microbial trace fossils (without cellular structures) may also be preserved on Mars: Discontinuities in structure or chemistry of the rock that are independent of physical or chemical gradients may be of biological origin. Ross Desert trace fossils can be used as a model for planning search strategies and for instrument design to find evidence of past Martian life.

Hydrogeochemical and stream sediment reconnaissance basic data report for Kingman NTMS Quadrangle, Arizona, California, and Nevada

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

Qualheim, B.J.

This report presents the results of the geochemical reconnaissance sampling in the Kingman 1 x 2 quadrangle of the National Topographical Map Series (NTMS). Wet and dry sediment samples were collected throughout the 18,770-km arid to semiarid area and water samples at available streams, springs, and wells. Neutron activation analysis of uranium and trace elements and other measurements made in the field and laboratory are presented in tabular hardcopy and microfiche format. The report includes five full-size overlays for use with the Kingman NTMS 1 : 250,000 quadrangle. Water sampling sites, water sample uranium concentrations, water-sample conductivity, sediment sampling sites,more » and sediment-sample total uranium and thorium concentrations are shown on the separate overlays. General geological and structural descriptions of the area are included and known uranium occurrences on this quadrangle are delineated. Results of the reconnaissance are briefly discussed and related to rock types in the final section of the report. The results are suggestive of uranium mineralization in only two areas: the Cerbat Mountains and near some of the western intrusives.« less

Experimental study on the influence of slickwater on shale permeability

NASA Astrophysics Data System (ADS)

Liu, Zhonghua; Bai, Baojun; Zhang, Zheyu; Tang, Jing; Zeng, Shunpeng; Li, Xiaogang

2018-02-01

There are two diametrically opposite views of the influence of slickwater on shale permeability among scholars at home and abroad. We used the shale outcrops rock samples from the Lower Silurian Longmaxi Formation in Sichuan Basin. The permeability of these dry samples before and after immersion in different solution systems were tested by pulse attenuation method. The experimental results show that the impregnation of different slickwater components and standard salt solution can promote the increase of the permeability of shale samples. The stress sensitivity of shale samples after liquid immersion is medium weak to weak. The sample stress sensitivity is weak after soaked by the synergist solution and Drag reducing agent solution, and the sensitivity of the sample stress is medium weak after immersed by the standard saline solution, defoamer solution and antiswelling solution; The Ki/K0 of the shale sample after liquid immersion on σi/σ0 is consistent with the exponential stress sensitive evaluation model. With the increase of soaking time, the increase of sample permeability increases first and then decreases.

Mines, prospects, and mineral sites, wilderness and RARE II areas, White Mountain National Forest, New Hampshire

USGS Publications Warehouse

Gazdik, G. C.; Harris, Gazdik; Welsh, R. A.; Girol, V. P.

1988-01-01

The areas investigated are located in the White Mountain National Forest in Coos, Grafton, and Carroll Counties, New Hampshire. Personnel from the U.S. Bureau of Mines conducted field reconnaissance of the westernmost areas, Kinsman Mountain, Mt. Wolf-Gordon Pond, Jobildunk, and Carr Mountain, in the fall of 1980. Field reconnaissance of the eastern areas, Great Gulf, Presidential Range-Dry River, Dartmouth Range, Pemigewasset and Wild River was conducted in the spring of 1981. A total of 237 rock and 103 panned-concentrate samples were collected during the investigations. Reconnaissance radiometric ground surveys were conducted at selected locations.

Fossil intermediate-depth earthquakes in subducting slabs linked to differential stress release

NASA Astrophysics Data System (ADS)

Scambelluri, Marco; Pennacchioni, Giorgio; Gilio, Mattia; Bestmann, Michel; Plümper, Oliver; Nestola, Fabrizio

2017-12-01

The cause of intermediate-depth (50-300 km) seismicity in subduction zones is uncertain. It is typically attributed either to rock embrittlement associated with fluid pressurization, or to thermal runaway instabilities. Here we document glassy pseudotachylyte fault rocks—the products of frictional melting during coseismic faulting—in the Lanzo Massif ophiolite in the Italian Western Alps. These pseudotachylytes formed at subduction-zone depths of 60-70 km in poorly hydrated to dry oceanic gabbro and mantle peridotite. This rock suite is a fossil analogue to an oceanic lithospheric mantle that undergoes present-day subduction. The pseudotachylytes locally preserve high-pressure minerals that indicate an intermediate-depth seismic environment. These pseudotachylytes are important because they are hosted in a near-anhydrous lithosphere free of coeval ductile deformation, which excludes an origin by dehydration embrittlement or thermal runaway processes. Instead, our observations indicate that seismicity in cold subducting slabs can be explained by the release of differential stresses accumulated in strong dry metastable rocks.

Water uptake of trees in a montane forest catchment and the geomorphological potential of root growth in Boulder Creek Critical Zone Observatory, Rocky Mountains, Colorado

NASA Astrophysics Data System (ADS)

Skeets, B.; Barnard, H. R.; Byers, A.

2011-12-01

The influence of vegetation on the hydrological cycle and the possible effect of roots in geomorphological processes are poorly understood. Gordon Gulch watershed in the Front Range of the Rocky Mountains, Colorado, is a montane climate ecosystem of the Boulder Creek Critical Zone Observatory whose study adds to the database of ecohydrological work in different climates. This work sought to identify the sources of water used by different tree species and to determine how trees growing in rock outcrops may contribute to the fracturing and weathering of rock. Stable isotopes (18O and 2H) were analyzed from water extracted from soil and xylem samples. Pinus ponderosa on the south-facing slope consumes water from deeper depths during dry periods and uses newly rain-saturated soils, after rainfall events. Pinus contorta on the north -facing slope shows a similar, expected response in water consumption, before and after rain. Two trees (Pinus ponderosa) growing within rock outcrops demonstrate water use from cracks replenished by new rains. An underexplored question in geomorphology is whether tree roots growing in rock outcrops contribute to long-term geomorphological processes by physically deteriorating the bedrock. The dominant roots of measured trees contributed approximately 30 - 80% of total water use, seen especially after rainfall events. Preliminary analysis of root growth rings indicates that root growth is capable of expanding rock outcrop fractures at an approximate rate of 0.6 - 1.0 mm per year. These results demonstrate the significant role roots play in tree physiological processes and in bedrock deterioration.

Laboratory Investigation of the Effect of Water-Saturation on Seismic Wave Dispersion in Carbonates

NASA Astrophysics Data System (ADS)

Li, W.; Pyrak-Nolte, L. J.

2009-12-01

In subsurface rock, fluid content changes with time through natural causes or because of human interactions, such as extraction or sequestration of fluids. The ability to monitor, seismically, fluid migration in the subsurface requires an understanding of the effects that the degree of saturation and spatial distribution of fluids have on wave propagation in rock. In this study, we find that the seismic dispersion of a dry carbonate rock can be masked by saturating the sample. We used a laboratory mini-seismic array to monitor fluid invasion and withdrawal in a carbonate rock with fabric-controlled layering. Experiments were performed on prismatic samples of Austin Chalk measuring 50mm x 50mm x 100mm. The epoxy-sealed samples contained an inlet and an outlet port to enable fluid invasion/withdrawal along the long axis of the sample. Water was infused and withdrawn from the sample at a rate of 1ml/hr. The mini-seismic array consisted of a set of 12 piezoelectric contact transducers, each with a central frequency 1.0 MHz. Three compressional wave source-receiver pairs and three shear wave source-receiver pairs were used to probe along the length of the sample prior to invasion and during invasion and withdrawal of water from the sample. A pressure transducer was used to record the fluid pressure simultaneously with the full transmitted wave forms every 15-30 minutes. A wavelet analysis determined the effect of fluid invasion on velocity dispersion. We observed that the compressional wave dispersion was more sensitive to changes in saturation than the shear wave dispersion. When the sample was unsaturated, the high frequency components of the compressional wave (1.2MHz to 2MHz) had lower velocities (~ 2750m/s) than the low frequency components, which decrease monotonically from 2890 m/s for 0.2MHz to 1.2 MHz. As water infused the sample, the dispersion weakened. When the sample as fully saturated, the compressional wave velocity was frequency independent. The functional form of the dependence of the shear wave velocity on frequency is relatively constant with fluid saturation, but the magnitude of the velocity decreased (~35 m/s) with increasing saturation. From theoretical calculations, the shear modulus increased during water invasion and was independent of frequency. However, the changes in the Young’s modulus with water invasion depended on the frequency of observation. When 46.5ml was infused into the sample, the Young’s modulus interpreted from the high-frequency components (wavelength from 1.43mm to 2.4mm) increased 70%, while the modulus from the low-frequency components (wavelengths vary from 1.4cm to 3.4mm) increased between 20% and 55%. Interpreting seismic data to determine fluid saturation in rock with fabric-controlled layering requires an understanding of the seismic dispersion properties of the rock in addition to the ability of fluids on alter or mask the dispersion. Acknowledgments: The authors wish to acknowledge support of this work by the Geosciences Research Program, Office of Basic Energy Sciences US Department of Energy (DEFG02-97ER14785 08), by Exxon Mobil Upstream Research Company and the GeoMathematical Imaging Group at Purdue University.

Preliminary report on radiocarbon dating of cryptoendolithic microorganisms

NASA Technical Reports Server (NTRS)

Bonani, G.; Friedmann, E. I.; Ocampo-Friedmann, R.; McKay, C. P.; Woelfli, W.

1988-01-01

The existence of microbial communities living inside desert rocks has been reported by FRIEDMANN et al. (1967, 1976), first in rocks collected from the hot and dry Negev desert and later in rocks in the frigid Ross Desert of Southern Victoria Land, Antarctica. The extremely inhospitable climatic conditions in both places has led to the suggestion that these organisms have very low rates of metabolism and may, in addition, be very old (FRIEDMANN 1982). Our preliminary measurements showed a 14C deficiency indicating a carbon age in the order of magnitude of 10(3) years.

Rockfall hazard assessment of nearly vertical rhyolite tuff cliff faces by using terrestrial laser scanner, UAV and FEM analyses

NASA Astrophysics Data System (ADS)

Török, Ákos; Barsi, Árpád; Görög, Péter; Lovas, Tamás; Bögöly, Gyula; Czinder, Balázs; Vásárhelyi, Balázs; Molnár, Bence; József Somogyi, Árpád

2017-04-01

Nearly vertical rhyolite tuff cliff faces are located in NE-Hungary representing rock fall hazard in the touristic region of Sirok. Larger blocks of the cliff have fallen in recent years menacing tourists and human lives. The rhyolite tuff, that forms the Castle Hill was formed during Miocene volcanism and comprises of brecciated lapilli tuffs and tuffs with intercalating ignimbritic horizons. The paper focuses on the 3D mapping of cliff faces and modeling of rock fall hazard. The topography and 3D model of the cliff was obtained by using GNSS supported terrestrial laser scanner and UAV. With imaging techniques of UAV a Triangulated Irregular Network (TIN) model was developed that contained triangles with 5-10 cm side lengths. GNSS supported terrestrial laser scanning allowed the observation with a resolution 1-5 cm of point spacing. The point clouds were further processed and with the combination of laser scanner and UAV data a 3D model of the studied cliff faces were obtained. Geological parameters for rock fall analyses included both field observations and laboratory tests. The lithotypes were identified on the field and were sampled for rock mechanical laboratory analyses. Joint- and fault system was mapped and visualized by using Rocscience Dip. EN test methods were used to obtain the density properties of various lithotypes of rhyolite tuff. Other standardized EN tests included ultrasonic pulse velocity, water absorption, indirect tensile strength (Brasilian), uniaxial compressive strength and modulus of elasticity of air dry and of water saturated samples. GSI values were denoted based on filed observations and rock mass properties. The stability analyses of cliff faces were made by using 2D FEM software (Phase 2). Cross sections were evaluated and global factor of safety was also calculated. The modeled displacements were in the order of few centimeters; however several locations were pinpointed where wedge failure and planar slip surfaces were identified as major cliff stability hazards. These were associated with the major joint systems dissecting cliff faces. This research have proved that the combined methods of field surveying, imaging techniques, data processing and FEM modelling with rock mechanical laboratory analyses allowed the identification of major rock fall hazards even at areas which are difficult to access.

Elastic anisotropy of core samples from the Taiwan Chelungpu Fault Drilling Project (TCDP): direct 3-D measurements and weak anisotropy approximations

NASA Astrophysics Data System (ADS)

Louis, Laurent; David, Christian; Špaček, Petr; Wong, Teng-Fong; Fortin, Jérôme; Song, Sheng Rong

2012-01-01

The study of seismic anisotropy has become a powerful tool to decipher rock physics attributes in reservoirs or in complex tectonic settings. We compare direct 3-D measurements of P-wave velocity in 132 different directions on spherical rock samples to the prediction of the approximate model proposed by Louis et al. based on a tensorial approach. The data set includes measurements on dry spheres under confining pressure ranging from 5 to 200 MPa for three sandstones retrieved at a depth of 850, 1365 and 1394 metres in TCDP hole A (Taiwan Chelungpu Fault Drilling Project). As long as the P-wave velocity anisotropy is weak, we show that the predictions of the approximate model are in good agreement with the measurements. As the tensorial method is designed to work with cylindrical samples cored in three orthogonal directions, a significant gain both in the number of measurements involved and in sample preparation is achieved compared to measurements on spheres. We analysed the pressure dependence of the velocity field and show that as the confining pressure is raised the velocity increases, the anisotropy decreases but remains significant even at high pressure, and the shape of the ellipsoid representing the velocity (or elastic) fabric evolves from elongated to planar. These observations can be accounted for by considering the existence of both isotropic and anisotropic crack distributions and their evolution with applied pressure.

Occurrence of the Great Lake's most recent invader, Hemimysis anomala, in the diet of fishes in southeastern Lake Ontario

USGS Publications Warehouse

Lantry, B.F.; Walsh, M.G.; Johnson, J. H.; McKenna, J.E.

2010-01-01

The Ponto-Caspian mysid, Hemimysis anomala, was first observed in southeastern Lake Ontario in May 2006. During July and August 2007, gill nets were fished in 6 to 8 m of water at two locations of known Hemimysis colonization in southeastern Lake Ontario to determine if fish that consume macroinvertebrates were beginning to include this new invasive mysid in their diets. Of nine fish species captured in August, September, and October 2007, three species had consumed Hemimysis: alewife (Alosa pseudoharengus), rock bass (Ambloplites rupestris), and yellow perch (Perca flavescens); and six species had not: round goby Apollonia melanostoma, smallmouth bass Micropterus dolomieu, spottail shiner Notropis hudsonius, gizzard shad Dorosoma cepedianum, white perch Morone americana and log perch Percina caprodes. Diets of alewives from all samples were composed predominantly of Hemimysis (69.6% -100% frequency of occurrence, 46.0%–74.5% dry weight diet composition). Two of 6 rock bass stomachs sampled in August contained ≥ 98.9% Hemimysis (10 and 40 individuals each) and one of 61 yellow perch stomachs sampled in September contained 10.0% Hemimysis (6 individuals) and 90.0% fish. While Hemimysis were observed only sparsely in the diet of most nearshore fish, their predominance in alewife diets and their omnivorous feeding behavior indicated that they have the potential to alter energy flow in Great Lakes' foodwebs.

Comparison of β Values in Rocks Deduced From the Elastoacoustic Effect and From 3-Wave Mixing

NASA Astrophysics Data System (ADS)

Dangelo, R.; Winkler, K. W.; Johnson, D. L.

2002-12-01

We measure the changes in the speeds of sound in Berea, wet and dry, due to the application of non-isotropic stresses (elastoacoustic effect). From these measurements we deduce values of the 3rd order elastic constants, A,B,C. We insonify these same samples, immersed in a water tank, with well-characterized acoustic signals having frequency content f1 = 1.05 MHz and f2 = 0.95 MHz. The nonlinear properties of the samples generate a difference frequency component at Δ f = 100 kHz whose amplitude we measure (3-wave mixing). We analyze the combined effects of diffraction, attenuation, and nonlinearity on these difference frequency signals by means of the KZK equation, suitably modified to account for the actual frequency dependence of the attenuation in these samples. The attenuation of the higher frequency nonlinear signals, f1+f_2, 2f1, 2f2, precludes our ability to measure them. The values of β deduced from the 3-wave mixing measurements are in the hundreds whereas the values of β implied by the values of A,B,C are in the thousands. The same experiments on lucite yield β values consistent with each other: β ≈ 6. In lucite we are easily able to measure the higher frequency nonlinear signals. The high attenuation in rocks precludes their measurement at these frequencies.

Rock sample brought to earth from the Apollo 12 lunar landing mission

NASA Technical Reports Server (NTRS)

1969-01-01

A scientist's gloved hand holds one of the numerous rock samples brought back to Earth from the Apollo 12 lunar landing mission. This sample is a highly shattered basaltic rock with a thin black-glass coating on five of its six sides. Glass fills fractures and cements the rock together. The rock appears to have been shattered and thrown out by a meteorite impact explosion and coated with molten rock material before the rock fell to the surface.

Black bear habitat use in relation to food availability in the Interior Highlands of Arkansas

USGS Publications Warehouse

Clark, Joseph D.; Clapp, Daniel L.; Smith, Kimberly G.; Ederington, Belinda

1994-01-01

A black bear (Ursus americanus) food value index (FVI) was developed and calculated for forest cover type classifications on Ozark Mountain (White Rock) and Ouachita Mountain (Dry Creek) study areas in western Arkansas. FVIs are estimates of bear food production capabilities of the major forest cover types and were calculated using percent cover, mean fruit production scorings, and the dietary percentage of each major plant food species as variables. Goodness-of-fit analyses were used to determine use of forest cover types by 23 radio-collared female bears. Habitat selection by forest cover type was not detected on White Rock but was detected on Dry Creek. Use of habitats on Dry Creek appeared to be related to food production with the exception of regeneration areas, which were used less than expected but had a high FVI ranking. In general, pine cover types had low FVI rankings and were used less than expected by bears. Forest management implications are discussed. 

Device Acquires and Retains Rock or Ice Samples

NASA Technical Reports Server (NTRS)

Giersch, Louis R.; Backes, Paul G.

2009-01-01

The Rock Baller is a sample acquisition tool that improves sample retention. The basic elements of the Rock Baller are the tool rotation axis, the hub, the two jaws, and the cutting blades, which are located on each of the jaws. The entire device rotates about the tool rotation axis, which is aligned parallel to the nominal normal direction of the parent rock surface. Both jaws also rotate about the jaw axis, which is perpendicular to the tool rotation axis, at a rate much slower than the rotation about the tool rotation axis. This movement gradually closes the jaws into a nearly continuous hemispherical shell that encloses the sample as it is cut from the parent rock. When required the jaws are opened to release the sample. The hemispherical cutting method eliminates the sample retention problems associated with existing sample acquisition methods that employ conventional cylindrical cutting. The resulting samples are hemispherical, or nearly hemispherical, and as a result the aspect ratio (sample depth relative to sample radius) is essentially fixed. This fixed sample aspect ratio may be considered a drawback of the Rock Baller method, as samples with a higher aspect ratio (more depth, less width) may be considered more scientifically valuable because such samples would allow for a broader inspection of the geological record. This aspect ratio issue can be ameliorated if the Rock Baller is paired with a device similar to the Rock Abrasion Tool (RAT) used on the Mars Exploration Rovers. The RAT could be used to first grind into the surface of the parent rock, after which the Rock Baller would extract a sample from a depth inside the rock that would not have been possible without first using the RAT. Other potential applications for this technology include medical applications such as the removal of tissue samples or tumors from the body, particularly during endoscopic, laparoscopic, or thoracoscopic surgeries.

Impact of straw and rock-fragment mulches on soil moisture and early growth of holm oaks in a semiarid area

Treesearch

M. N. Jimenez; J. R. Pinto; M. A. Ripoll; A. Sanchez-Miranda; F. B. Navarro

2017-01-01

Planted seedlings and saplings usually exhibit low survival and growth rates under dry Mediterranean environments, especially late-successional species such as Quercus. In this work, we studied the effects of straw and rock fragment mulches on the establishment conditions of holm oak (Quercus ilex L. subsp. ballota (Def.) Samp.) in SE Spain. Soil moisture was...

The effect of dilatancy on the unloading behavior of Mt. Helen tuff

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

Attia, A.V.; Rubin, M.B.

1993-11-01

In order to understand the role of rock dilatancy in modeling the response of partially saturated rock formations to underground nuclear explosions, we have developed a thermodynamically consistent model for a porous material, partially saturated with fluid. This model gives good predictions of the unloading behavior of dry, partially saturated, and fully saturated Mt. Helen tuff, as measured by Heard.

Reaching 1 m deep on Mars: the Icebreaker drill.

PubMed

Zacny, K; Paulsen, G; McKay, C P; Glass, B; Davé, A; Davila, A F; Marinova, M; Mellerowicz, B; Heldmann, J; Stoker, C; Cabrol, N; Hedlund, M; Craft, J

2013-12-01

The future exploration of Mars will require access to the subsurface, along with acquisition of samples for scientific analysis and ground-truthing of water ice and mineral reserves for in situ resource utilization. The Icebreaker drill is an integral part of the Icebreaker mission concept to search for life in ice-rich regions on Mars. Since the mission targets Mars Special Regions as defined by the Committee on Space Research (COSPAR), the drill has to meet the appropriate cleanliness standards as requested by NASA's Planetary Protection Office. In addition, the Icebreaker mission carries life-detection instruments; and in turn, the drill and sample delivery system have to meet stringent contamination requirements to prevent false positives. This paper reports on the development and testing of the Icebreaker drill, a 1 m class rotary-percussive drill and triple redundant sample delivery system. The drill acquires subsurface samples in short, approximately 10 cm bites, which makes the sampling system robust and prevents thawing and phase changes in the target materials. Autonomous drilling, sample acquisition, and sample transfer have been successfully demonstrated in Mars analog environments in the Arctic and the Antarctic Dry Valleys, as well as in a Mars environmental chamber. In all environments, the drill has been shown to perform at the "1-1-100-100" level; that is, it drilled to 1 m depth in approximately 1 hour with less than 100 N weight on bit and approximately 100 W of power. The drilled substrate varied and included pure ice, ice-rich regolith with and without rocks and with and without 2% perchlorate, and whole rocks. The drill is currently at a Technology Readiness Level (TRL) of 5. The next-generation Icebreaker drill weighs 10 kg, which is representative of the flightlike model at TRL 5/6.

Constraints in the hot-dry-rock resources of the united states

USGS Publications Warehouse

Sass, John; Guffanti, Marianne; ,

1993-01-01

As with hydrothermal systems, the western U.S has higher HDR potential overall than the eastern U.S. because geothermal gradients on average are higher in the west. Nevertheless, some attractive exploration targets occur in the eastern U.S. The most favorable target in the eastern U.S. (defined here to include the Great Plains province) is one in which the heat flow from the basement rocks is higher than average, either due to heat generation from highly radioactive rocks or to a plume of hot water driven upwards from greater depths by convection, and where such basement rocks are blanketed by one or more kilometers of sedimentary material having a low thermal conductivity.

Geochemical Characteristics of Aquifer system in Taichung Area, Central Taiwan

NASA Astrophysics Data System (ADS)

Tsai, Jui-Fen; Chen, Cheng-Hong; Liu, Tsung-Kwei

2016-04-01

For understanding the relationship between water bodies and host rocks and getting more information for groundwater in Taichung area, Central Taiwan, we systematically analyzed the stable isotopes (hydrogen and oxygen), helium isotopes and radon concentrations of dissolved gases from 54 groundwater, 39 river and 4 rain samples collected from Taichung Basin in wet and dry seasons of the year 2015. In the δ18O vs. δD plot, all samples present a linear trend similar to local meteoric water, indicating a meteoric origin. However, river samples are relative lighter than rain samples, it appears that the rivers are mainly recharged from precipitation of high-elevation areas with a lighter isotopic composition. Because the seasonal isotopic variation of river samples is significant, we calculated relative contribution of precipitation by seasons using the mass balance equation. Results show that the precipitation in the rainy season is the major source of groundwater. The helium isotopic ratio in dissolved gases of most groundwater samples are close to 1 RA (RA = 3He/4He ratio of air), except the sample from Wu-Feng well that exhibits 0.3 RA. This sample also has an older C-14 age (˜27000 yrs.) than others (<200 yrs.), implying that the dissolved helium is likely affected by radiogenic 4He of surrounding rocks. The average concentration of radon for groundwater in the northern section of Taichung Basin is 20.3 Bq/L, which is higher than that of the southern section (14.5 Bq/L). Variations of radon concentrations in the two sections may be related to the different drainage systems (Paleo-Dajia River vs. Wu River), in which sediments from Paleo-Dajia River may contain higher uranium concentrations. On the other hand, water in rivers usually contains undetectable radon (<0.37 Bq/L) because it rapidly escapes to the atmosphere. However, river samples from the central part of basin have radon concentrations ranging between 1 and 3 Bq/L, reflecting that the sampling sites are in the vicinity of points of groundwater inflow. This study illustrates the utility of hydrogen and oxygen isotopes to trace the groundwater source and determine the seasonal contribution ratios of precipitation to groundwater recharge, and demonstrates the advantage of using dissolved gas to investigate the groundwater-host rocks interaction. Key words: Central Taiwan, groundwater, dissolved gas, helium isotope, hydrogen and oxygen isotopes, water radon

Microstructural controls on the macroscopic behavior of geo-architected rock samples

NASA Astrophysics Data System (ADS)

Mitchell, C. A.; Pyrak-Nolte, L. J.

2017-12-01

Reservoir caprocks, are known to span a range of mechanical behavior from elastic granitic units to visco-elastic shale units. Whether a rock will behave elastically, visco-elastically or plastically depends on both the compositional and textural or microsctructural components of the rock, and how these components are spatially distributed. In this study, geo-architected caprock fabrication was performed to develop synthetic rock to study the role of rock rheology on fracture deformations, fluid flow and geochemical alterations. Samples were geo-architected with Portland Type II cement, Ottawa sand, and different clays (kaolinite, illite, and Montmorillonite). The relative percentages of these mineral components are manipulated to generate different rock types. With set protocols, the mineralogical content, texture, and certain structural aspects of the rock were controlled. These protocols ensure that identical samples with the same morphological and mechanical characteristics are constructed, thus overcoming issues that may arise in the presence of heterogeneity and high anisotropy from natural rock samples. Several types of homogeneous geo-architected rock samples were created, and in some cases the methods were varied to manipulate the physical parameters of the rocks. Characterization of rocks that the samples exhibit good repeatability. Rocks with the same mineralogical content generally yielded similar compressional and shear wave velocities, UCS and densities. Geo-architected rocks with 10% clay in the matrix had lower moisture content and effective porosities than rocks with no clay. The process by which clay is added to the matrix can strongly affect the resulting compressive strength and physical properties of the geo-architected sample. Acknowledgment: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Geosciences Research Program under Award Number (DE-FG02-09ER16022).

Empirical relations of rock properties of outcrop and core samples from the Northwest German Basin for geothermal drilling

NASA Astrophysics Data System (ADS)

Reyer, D.; Philipp, S. L.

2014-09-01

Information about geomechanical and physical rock properties, particularly uniaxial compressive strength (UCS), are needed for geomechanical model development and updating with logging-while-drilling methods to minimise costs and risks of the drilling process. The following parameters with importance at different stages of geothermal exploitation and drilling are presented for typical sedimentary and volcanic rocks of the Northwest German Basin (NWGB): physical (P wave velocities, porosity, and bulk and grain density) and geomechanical parameters (UCS, static Young's modulus, destruction work and indirect tensile strength both perpendicular and parallel to bedding) for 35 rock samples from quarries and 14 core samples of sandstones and carbonate rocks. With regression analyses (linear- and non-linear) empirical relations are developed to predict UCS values from all other parameters. Analyses focus on sedimentary rocks and were repeated separately for clastic rock samples or carbonate rock samples as well as for outcrop samples or core samples. Empirical relations have high statistical significance for Young's modulus, tensile strength and destruction work; for physical properties, there is a wider scatter of data and prediction of UCS is less precise. For most relations, properties of core samples plot within the scatter of outcrop samples and lie within the 90% prediction bands of developed regression functions. The results indicate the applicability of empirical relations that are based on outcrop data on questions related to drilling operations when the database contains a sufficient number of samples with varying rock properties. The presented equations may help to predict UCS values for sedimentary rocks at depth, and thus develop suitable geomechanical models for the adaptation of the drilling strategy on rock mechanical conditions in the NWGB.

Controls of Soil Spatial Variability in a Dry Tropical Forest.

PubMed

Pulla, Sandeep; Riotte, Jean; Suresh, H S; Dattaraja, H S; Sukumar, Raman

2016-01-01

We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2) soil spatial variability in a seasonally dry tropical forest (SDTF) in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10 cm), rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH), and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling) in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3(-)-N nor NH4(+)-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief.

Controls of Soil Spatial Variability in a Dry Tropical Forest

PubMed Central

Pulla, Sandeep; Riotte, Jean; Suresh, H. S.; Dattaraja, H. S.; Sukumar, Raman

2016-01-01

We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2) soil spatial variability in a seasonally dry tropical forest (SDTF) in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10cm), rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH), and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling) in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3−-N nor NH4+-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief. PMID:27100088

Ignimbrite as a substrate for endolithic life in the hyper-arid Atacama Desert: Implications for the search for life on Mars

NASA Astrophysics Data System (ADS)

Wierzchos, Jacek; Davila, Alfonso F.; Artieda, Octavio; Cámara-Gallego, Beatriz; de los Ríos, Asunción; Nealson, Kenneth H.; Valea, Sergio; Teresa García-González, M.; Ascaso, Carmen

2013-06-01

The hyper-arid core of the Atacama Desert in Chile is considered the driest and most life-limited place on Earth, with few habitats capable of sustaining an active microbial ecosystem. As such, it is one of the best terrestrial analogues of the extreme arid conditions on Mars, and an ideal environment to explore survival and biological adaptation strategies as the environment becomes increasingly dry. Here we show that weakly welded rhyolitic ignimbrites in this desert are abundantly colonized by endolithic cyanobacteria and associated heterotrophic bacteria. We propose that the porous ignimbrite interior provides protection from damaging UV radiation and excessive levels of visible light. Rock porosity also favors cell hydration through water retention after scarce rainfall events, even when the surrounding environment remains stubbornly dry. This is the first known example of an endolithic microbial community colonizing ignimbrite rocks in an extremely dry environment. The existence of a habitat capable of supporting abundant phototrophic and heterotrophic communities in an environment that precludes most life forms suggests that, if similar deposits are found on Mars, these should be considered important targets in the search for life. Indeed, ignimbrite rocks have been tentatively identified in Gale Crater, the landing site of the Mars Science Laboratory (MSL) mission and could be directly analyzed by its rover Curiosity.

Designing a monitoring network for contaminated ground water in fractured chalk

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

Nativ, R.; Adar, E.M.; Becker, A.

1999-01-01

One of the challenges of monitoring network design in a fractured rock setting is the heterogeneity of the rocks. This paper summarizes the activities and problems associated with the monitoring of contaminated groundwater in porous, low-permeability fractured chalk in the Negev Desert, Israel. Preferential flow documented in the study area required siting the monitoring boreholes in the predominant fracture systems. Lineaments traced from aerial photographs were examined in the field to sort out the large-extension, through-going, multilayer fracture systems crossing the study area. At each proposed drilling site, these fractures were exposed below the sediment cover using trenches. Slanted boreholesmore » were drilled at a distance from the fracture systems so that each borehole would intersect the targeted fracture plane below the water table. Based on their short recovery period and contaminated ground water, these newly drilled, fracture-oriented boreholes appeared to be better connected to preferential flowpaths crossing the industrial site than the old boreholes existing on site. Other considerations concerning the drilling and logging of monitoring boreholes in a fractured media were: (1) coring provides better documentation of the vertical fracture distribution, but dry augering is less costly and enables immediate ground water sampling and the sampling of vadose rock for contaminant analysis; (2) caliper and TV camera logs appear to provide only partial information regarding the vertical fracture distribution; and (3) the information gained by deepening the monitoring boreholes and testing fractures crossing their uncased walls has to be carefully weighed against the risk of potential cross-contamination through the monitoring boreholes, which is enhanced in fractured media.« less

Hot dry rock geothermal energy: status of exploration and assessment. Report No. 1 of the hot dry rock assessment panel

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

Not Available

1977-06-01

The status of knowledge of attempts to utilize hot dry rock (HDR) geothermal energy is summarized. It contains (1) descriptions or case histories of the ERDA-funded projects at Marysville, MT, Fenton Hill, NM, and Coso Hot Springs, CA; (2) a review of the status of existing techniques available for exploration and delineation of HDR; (3) descriptions of other potential HDR sites; (4) definitions of the probable types of HDR resource localities; and (5) an estimate of the magnitude of the HDR resource base in the conterminous United States. The scope is limited to that part of HDR resource assessment relatedmore » to the determination of the extent and character of HDR, with emphasis on the igneous-related type. It is estimated that approximately 74 Q (1 Q = 1,000 Quads) of heat is stored in these sites within the conterminous U.S. at depths less than 10 km and temperatures above 150/sup 0/C, the minimum for power generation. (Q = 10/sup 18/ BTU = 10/sup 21/J; the total U.S. consumption for 1972 was approximately 0.07 Q). Approximately 6300 Q are stored in the conduction-dominated parts of the crust in the western U.S. (23% of the total surface area), again at depths less than 10 km and temperatures above 150/sup 0/C. Nearly 10,000 Q are believed to be contained in crustal rocks underlying the entire conterminous U.S., at temperatures above 150/sup 0/C. The resource base is significantly larger for lower grade heat. (JGB)« less

Study of sample drilling techniques for Mars sample return missions

NASA Technical Reports Server (NTRS)

Mitchell, D. C.; Harris, P. T.

1980-01-01

To demonstrate the feasibility of acquiring various surface samples for a Mars sample return mission the following tasks were performed: (1) design of a Mars rover-mounted drill system capable of acquiring crystalline rock cores; prediction of performance, mass, and power requirements for various size systems, and the generation of engineering drawings; (2) performance of simulated permafrost coring tests using a residual Apollo lunar surface drill, (3) design of a rock breaker system which can be used to produce small samples of rock chips from rocks which are too large to return to Earth, but too small to be cored with the Rover-mounted drill; (4)design of sample containers for the selected regolith cores, rock cores, and small particulate or rock samples; and (5) design of sample handling and transfer techniques which will be required through all phase of sample acquisition, processing, and stowage on-board the Earth return vehicle. A preliminary design of a light-weight Rover-mounted sampling scoop was also developed.

Effects of Climate on Co-evolution of Weathering Profiles and Hillscapes

NASA Astrophysics Data System (ADS)

Anderson, R. S.; Rajaram, H.; Anderson, S. P.

2017-12-01

Considerable debate revolves around the relative importance of rock type, tectonics, and climate in creating the architecture of the critical zone. It has recently been proposed that differences in the depths and patterns of weathering between landscapes in Colorado's Front Range and South Carolina's piedmont can be attributed to the state of stress in the rock imposed by the magnitude and orientation the regional stresses with respect to the ridgelines (St. Claire et al., 2016). We argue for the importance of the climate, and in particular, in temperate regions, the amount of recharge. We employ numerical models of hillslope evolution between bounding erosional channels, in which the degree of rock weathering governs the rate of transformation of rock to soil. As the water table drapes between the stream channels, fresh rock is brought into the weathering zone at a rate governed by the rate of incision of the channels. We track the chemical weathering of rock, represented by alteration of feldspar to clays, which in turn requires calculation of the concentration of reactive species in the water along hydrologic flow paths. We present results from analytic solutions to the flow field in which travel times can be efficiently assessed. Below the water table, flow paths are hyperbolic, taking on considerable lateral components as they veer toward the bounding channels that serve as drains to the hillslope. We find that if water is far from equilibrium with respect to weatherable minerals at the water table, as occurs in wet, slowly-eroding landscapes, deep weathering can occur well below the water table to levels approximating the base of the bounding channels. In dry climates, on the other hand, the weathering zone is limited to a shallow surface - parallel layer. These models capture the essence of the observed differences in depth to fresh rock in both wet and dry climates without appeal to the state of stress in the rock.

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

NASA Astrophysics Data System (ADS)

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

2011-09-01

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

Quantification of rock slope terrain properties

NASA Astrophysics Data System (ADS)

Volkwein, Axel; Gerber, Werner

2017-04-01

Rockfall trajectory simulation codes need information on the terrain properties to formulate appropriate rebound models. Usually, the manuals of rockfall simulation codes give sketches or photographs of terrain samples [1,2]. Based on these the user can select suitable terrains for the simulation area. We now would like to start a discussion whether it is possible to numerically quantify the terrain properties which would make the ground assignment more objective. Different ground properties play a role for the interaction between a falling rock and the ground: • Elastic deformation • plastic deformation • Energy absorption • friction • hardness • roughness • surface vs. underground • etc. The question is now whether it is possible to quantify above parameters and to finally provide tables that contain appropriate simulation parameters. In a first attempt we suggest different methods or parameters that might be evaluated in situ: • Small scale drop tests • Light weight deflectometer (LWD) • Particle sizes • Sliding angle • Particle distribution • Soil cover • Water content Of course, above measurements will never perfectly fit to different mountain slopes. However, if a number of measurements has been made their spreading will give an idea on the natural variability of the ground properties. As an example, the following table gives an idea on how the ME and Evd values vary for different soils. Table 1: LWD measurements on different soil types [3] Ground type Soil layer Soil humidityEvd (median)σ (median)Evd (average) Humus-carb. < 10cm dry 17.4 6.8 15.6 Regosol 10 - 30cm dry 8.6 3.9 9.4 Brownish 30 - 50cm dry 12.1 3.2 11.7 Calcaric 30 - 50cm dry 7.5 3.3 7.0 Acid brownish70 - 100cmdry 7.8 2.1 7.7 Fahlgley 10 - 30cm dry 9.2 4.0 7.7 References [1] Bartelt P et al (2016) RAMMS::rockfall user manual v1.6. SLF, Davos. [2] Dorren L.K.A., 2015. Rockyfor3D (v5.2) revealed - Transparent description of the complete 3D rockfall model. ecorisQ paper (www.ecorisq.org): 32 p. [3] Hoffmann P. (2015) Härte von Böden. Bsc thesis, ZHAW Waedenswil.

Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

NASA Technical Reports Server (NTRS)

Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

2004-01-01

Terrestrial weathering processes in cold-desert climates such as the Dry Valleys of Antarctica may provide an excellent analog to chemical weathering and diagenesis of soils on Mars. Detailed studies of soil development and the chemical and mineralogical alterations occurring within soil columns in Wright Valley, Antarctica show incredible complexity in the upper meter of soil. Previous workers noted the ice-free Dry Valleys are the best terrestrial approximations to contemporary Mars. Images returned from the Pathfinder and Spirit landers show similarities to surfaces observed within the Dry Valleys. Similarities to Mars that exist in these valleys are: mean temperatures always below freezing (-20 C), no rainfall, sparse snowfall-rapidly removed by sublimation, desiccating winds, diurnal freeze-thaw cycles (even during daylight hours), low humidity, oxidative environment, relatively high solar radiation and low magnetic fields . The Dry Valley soils contain irregular distributions and low abundances of soil microorganisms that are somewhat unusual on Earth. Physical processes-such as sand abrasion-are dominant mechanisms of rock weathering in Antarctica. However, chemical weathering is also an important process even in such extreme climates. For example, ionic migration occurs even in frozen soils along liquid films on individual soil particles. It has also been shown that water with liquid-like properties is present in soils at temperatures on the order of approx.-80 C and it has been observed that the percentage of oxidized iron increases with increasing soil age and enrichments in oxidized iron occurs toward the surface. The presence of evaporates is evident and appear similar to "evaporite sites" within the Pathfinder and Spirit sites. Evaporites indicate ionic migration and chemical activity even in the permanently frozen zone. The presence of evaporates indicates that chemical weathering of rocks and possibly soils has been active. Authogenic zeolites have been identified within the soil columns because they are fragile; i.e. they are euhedral, unabraded, and unfractured, strongly suggesting in situ formation. Their presence in Antarctic samples is another indication that diagenic processes are active in cold-desert environments. The presence of zeolites, and other clays along with halites, sulfates, carbonates, and hydrates are to be expected within the soil columns on Mars at the Gusev and Isidis Planitia regions. The presence of such water-bearing minerals beneath the surface supplies one of the requirements to support biological activity on Mars.

Diminishing friction of joint surfaces as initiating factor for destabilising permafrost rocks?

NASA Astrophysics Data System (ADS)

Funk, Daniel; Krautblatter, Michael

2010-05-01

Degrading alpine permafrost due to changing climate conditions causes instabilities in steep rock slopes. Due to a lack in process understanding, the hazard is still difficult to asses in terms of its timing, location, magnitude and frequency. Current research is focused on ice within joints which is considered to be the key-factor. Monitoring of permafrost-induced rock failure comprises monitoring of temperature and moisture in rock-joints. The effect of low temperatures on the strength of intact rock and its mechanical relevance for shear strength has not been considered yet. But this effect is signifcant since compressive and tensile strength is reduced by up to 50% and more when rock thaws (Mellor, 1973). We hypotheisze, that the thawing of permafrost in rocks reduces the shear strength of joints by facilitating the shearing/damaging of asperities due to the drop of the compressive/tensile strength of rock. We think, that decreasing surface friction, a neglected factor in stability analysis, is crucial for the onset of destabilisation of permafrost rocks. A potential rock slide within the permafrost zone in the Wetterstein Mountains (Zugspitze, Germany) is the basis for the data we use for the empirical joint model of Barton (1973) to estimate the peak shear strength of the shear plane. Parameters are the JRC (joint roughness coefficient), the JCS (joint compressive strength) and the residual friction angle (φr). The surface roughness is measured in the field with a profile gauge to create 2D-profiles of joint surfaces. Samples of rock were taken to the laboratory to measure compressive strength using a high-impact Schmidt-Hammer under air-dry, saturated and frozen conditions on weathered and unweathered surfaces. Plugs where cut out of the rock and sand blasted for shear tests under frozen and unfrozen conditions. Peak shear strength of frozen and unfrozen rocks will be calculated using Barton's model. First results show a mean decrease of compressive strength of around 40% when frozen water-saturated rock is exposed to thawing. The friction of sand-blasted rock-plugs decreases by a mean value of 32% considering degradation of rocks by freeze-thaw cycles. Surface roughness could be measured succesfully with the profile gauge and the results show a significant difference between untouched and sheared joint surfaces in the field. Here we show, that shear resistance of rock joints will be diminshed just by the thawing of intact rock. This study will help to establish a sound concept for the destabilization of rocks in permafrost and provide the data for first stability modelling. This will be crucial for predict rock instability in permafrost regions. References: Barton, N. (1973): Review of new shear strength criterion for rock jonts. Engineering Geology 7: 287-332 Mellor, M. (1973): Mechanical Properties of Rocks at Low Temperatures. 2nd International Conference on Permafrost, Yakutsk, Siberia, 334-343.

Frictional Properties of Main Fault Gouge of Mont Terri, Switzerland

NASA Astrophysics Data System (ADS)

Aoki, K.; Seshimo, K.; Guglielmi, Y.; Nussbaum, C.; Shimamoto, T.; Ma, S.; Yao, L.; Kametaka, M.; Sakai, T.

2016-12-01

JAEA participated in the Fault Slip Experiment of Mont Terri Project which aims at understanding (i) the conditions for slip activation and stability of clay faults, and (ii) the evolution of the coupling between fault slip, pore pressure and fluids migration. The experiment uses SIMFIP probe to estimate (i) the hydraulic and elastic properties of fault zone elements, (ii) the state of stresses across the fault zone and (iii) the fault zone apparent strength properties (friction coefficient and cohesion). To elaborate on the Fault Slip Experiment, JAEA performed friction experiment of borehole cores of depths 47.2m and 37.3m using a rotary-shear low to high-velocity friction apparatus at Institute of Geology, China Earthquake Administration. Friction experiments were performed either dry with room humidity or with 30wt% of H2O, at a normal stress of 1.38 MPa and at low to intermediate slip rates ranging 0.21 microns/s to 2.1mm/s. Sample from a depth of 37.3 m is a fault rock with scaly fabric with calcite veins, whereas that from 47.2 m in depth is a pelitic rock that disaggregates easily with water. Main experimental results are summarized as follows. (1) Gouge samples from both depths exhibit slight velocity-strengthening at V below 0.021 mm/s and notable velocity strengthening at V above approximately 0.021 mm/s. Frictional regimes can be classified into low-velocity and intermediate-velocity regimes, characterized by slight and clear velocity-strengthening behaviors, respectively. (2) Wet gouge from a depth of 47.2 m has mss of 0.12 0.2 at low V and 0.11 0.24 at intermediate V, while dry gouge from the same depth has mss two to three times as high as that for the wet gouge from the same depth. (3) In contrast, both dry and wet gouges from a depth of 37.3 m has mss of around 0.4 to 0.74 at low V and from around 0.45 to 0.75 at intermediate V. There are almost no differences between the dry and wet gouges from this depth (4) The wet gouge from 47.2 m depths has clear slip zone at the gouge-moving piston interface, but clear slip zones are missing in wet gouge from 37.3 m depth. (5) It is hoped that the frictional strength from the present experiments would give some insight on the initiation conditions of fault slip during fluid injection. Results of four other depths will be discussed at the session.

Lunar Samples - Apollo 12

NASA Image and Video Library

1969-11-28

S69-60354 (29 Nov. 1969) --- A scientist's gloved hand holds one of the numerous rock samples brought back to Earth from the Apollo 12 lunar landing mission. The rocks are under thorough examination in the Manned Spacecraft Center's (MSC) Lunar Receiving Laboratory (LRL). This sample is a highly shattered basaltic rock with a thin black-glass coating on five of its six sides. Glass fills fractures and cements the rock together. The rock appears to have been shattered and thrown out by a meteorite impact explosion and coated with molten rock material before the rock fell to the surface.

Metamorphism of brecciated ANT rocks - Anorthositic troctolite 72559 and norite 78527. [Anorthositic-Noritic-Troctolitic

NASA Technical Reports Server (NTRS)

Nehru, C. E.; Warner, R. D.; Keil, K.; Taylor, G. J.

1978-01-01

Rake samples 72559 and 78527 are annealed rocks of ANT-suite mineralogy and bulk composition. The rocks were presumably derived from ancient lunar highland ANT rocks of cumulate origin. Sample 72559 is polymict and its precursors were anorthositic-troctolitic in composition. Sample 78527 is monomict and of noritic derivation. The precursors were brecciated due to impact processes; 72559 shows evidence of some impact melting. The samples were thermally metamorphosed forming rocks with granoblastic matrix textures. Coexisting matrix pyroxenes indicate equilibration temperatures of 950-1000 C for both rocks. Accessory opaque oxide minerals in the rocks show rather wide compositional variations. These probably primarily reflect compositional ranges inherited from the precursor/s with little integranular equilibration among them during metamorphism.

Intermediate-Depth Subduction Earthquakes Recorded by Pseudotachylyte in Dry Eclogite-Facies Oceanic Lithosphere from the Alps

NASA Astrophysics Data System (ADS)

Scambelluri, M.; Pennacchioni, G.; Gilio, M.; Bestmann, M.

2016-12-01

While geophysical studies and laboratory experiments provide much information on subduction earthquakes, field studies identifying the rock types for earthquake development and the deep seismogenic environments are still scarce. To date, fluid overpressure and volume decrease during hydrous mineral breakdown the widely favoured trigger of subduction earthquakes in serpentinized lithospheric mantle and hydrated low-velocity layers atop slabs. Here we document up to 40 cm-thick pseudotachylyte (PST) in Alpine oceanic gabbro and peridotite (2-2.5 GPa-550-620°C), the analogue of a modern cold subducting oceanic lithosphere. These rocks mostly remained unaltered dry systems; only very minor domains (<1%) record partial hydration and static eclogitic metamorphism. Meta-peridotite shows high-pressure olivine + antigorite (garnet + zoisite + chlorite after mantle plagioclase); meta-gabbro develops omphacite + zoisite + talc + chloritoid + garnet. Abundant syn-eclogitic pseudotachylyte cut the dry gabbro-peridotite and the eclogitized domains. In meta-peridotite, PST shows olivine, orthopyroxene, spinel microliths and clasts of high-pressure olivine + antigorite and garnet + zoisite + chlorite aggregates. In metagabbro, microfaults in damage zones near PST cut brecciated igneous pyroxene cemented by omphacite. In unaltered gabbro, glassy PST contains micron-scale garnet replacing plagioclase microliths during, or soon after, PST cooling. In the host rock, garnet coronas between igneous olivine and plagioclase only occur near PST and between closely spaced PST veins. Absence of garnet away from PST indicates that garnet growth was triggered by mineral seeds and by heat released by PST. The above evidence shows that pseudotachylyte formed at eclogite-facies conditions. In such setting, strong, dry, metastable gabbro-peridotite concentrate stress to generate large intermediate depth subduction earthquakes without much involvement of free fluid.

The Effect of Saturation on Shear Wave Anisotropy in a Transversely Isotropic Medium

NASA Astrophysics Data System (ADS)

Li, W.; Pyrak-Nolte, L. J.

2010-12-01

Seismic monitoring of fluid distributions in the subsurface requires an understanding of the effect of fluid saturation on the anisotropic properties of layered media. Austin Chalk is a carbonate rock composed mainly of calcite (99.9%) with fine bedding caused by a weakly-directed fabric. In this paper, we assess the shear-wave anisotropy of Austin Chalk and the effect of saturation on interpreting anisotropy based on shear wave velocity, attenuation and spectral content as a function of saturation. In the laboratory, we performed full shear-waveform measurements on several dry cubic samples of Austin Chalk with dimensions 50mm x 50mm x 50mm. Two shear-wave contact transducers (central Frequency 1 MHz) were use to send and receive signals. Data was collected for three orthogonal orientations of the sample and as a function of shear wave polarization relative to the layers in the sample. For the waves propagated parallel to the layers, both fast and slow shear waves were observed with velocities of 3444 m/s and 3193 m/s, respectively. It was noted that the minimum and maximum shear wave velocities did not occur when the shear wave polarization were perpendicular or parallel to the layering in the sample but occurred at an orientation of ~25 degrees from the normal to the layers. The sample was then vacuum saturated with water for approximately ~15 hours. The same measurements were performed on the saturated sample as those on the dry sample. Both shear wave velocities observed decreased upon water-saturation with corresponding velocities of 3155 m/s and 2939 m/s, respectively. In the dry condition the difference between the fast and slow shear wave velocities was 250 m/s. This difference decreased to 215 m/s after fluid saturation. In both the dry and saturated condition, the shear wave velocity for waves propagated perpendicularly to the layers was independent of polarization and had the same magnitude as that of the slow shear wave. A wavelet analysis was performed to determine changes in the spectral content of the signals upon saturation as well velocity dispersion. We found that (1) low frequency components exhibit a larger difference in time delay between the fast and slow shear waves for the water-saturated condition than for the dry condition; (2) that high frequency components have relatively small differences in time delay between the dry and saturated conditions; and (3) the dominant frequency shifted to lower frequencies for the fast shear wave upon saturation while no change in dominant frequency was observed for the slow shear wave upon saturation. Thus, fluid saturation affects shear velocity as well as the spectral content of the signal. Acknowledgments: The authors wish to acknowledge support of this work by the Geosciences Research Program, Office of Basic Energy Sciences US Department of Energy (DE-FG02-09ER16022), by Exxon Mobil Upstream Research Company and the GeoMathematical Imaging Group at Purdue University.

Complex resistivity spectra in relation to multiscale pore geometry in carbonates and mixed-siliciclastic rocks

NASA Astrophysics Data System (ADS)

Norbisrath, Jan Henrik

Carbonate rocks are known to have complex and heterogeneous pore structures, which result from their biogenic origin and strong affinity for diagenetic processes that change their pore structure after burial. The combination of sheer endless variations of precursor biogenic material, depositional environments, and diagenetic effects results in rocks that are interesting to study but intricate to understand. Many schemes to categorize the diversity of carbonate rocks are in use today; most are based on the macropore structure and qualitative thin-section analysis. Many studies, however, acknowledge that micropores have a significant influence on the macroscopic petrophysical rock properties, which are essential to determine reservoir quality. Micropores are, by definition, smaller than the thickness of a thin-section (< 30 microm) and hence cannot be quantified with conventional methods. For their analysis, scanning electron microscopy (SEM) is the logical next step. The challenge is that mechanical polishing methods produce excessive surface roughness at micron scale; the resulting surfaces are not suited for quantification of micropores. Advances in broad-ion-beam (BIB) milling enable preparation of nanometer-precision 2D sections that are suited for quantitative analysis with the SEM. To accomplish the objective of accurate quantification of carbonate micropores, part one of this dissertation employs the BIB-SEM technique on a variety of carbonate rock samples and finds four major carbonate microporosity types: (1) small intercrystalline, (2) large inter-crystalline, (3) intercement, and (4) micromoldic. Each microporosity type shows a distinct capacity to conduct electrical charge, which largely controls the magnitude and range of cementation factors (m) in rocks with such microporosity type. The BIB-SEM method is also used on a dataset of mixed carbonate-siliciclastic (mudrock) samples with high kerogen and pyrite content. Results show that the nanopore geometry here has little influence on cementation factors, and instead porosity is the main control on m in mudrocks. Cementation factors are crucial for estimates of oil-in-place and water saturation in a wireline application, and a slight change of (assumed) cementation factor can change the interpreter's evaluation from dry hole to discovery. Therefore, accurate determination of cementation factors is a critical task in formation evaluation, similar to accurate estimates of permeability. To achieve this goal, this dissertation utilizes a new approach of using complex resistivity spectra (CRS) to assess the pore geometry and its resulting electrical and fluid flow properties. Specifically, frequency dispersion of complex resistivity in the kHz range is used as input for a new model to predict cementation factor and permeability in a wide variety of core plug samples. The underlying concept that relates CRS to flow properties is that both are related to pore geometry. CRS are linked to pore geometry by interfacial polarization effects at the fluid-rock boundary that control the phase and amplitude shift of an applied alternating current. Larger interfacial area results in higher phase shifts, but also indicates a more intricate pore structure that often results in lower permeability and higher cementation factors. The findings from this dissertation imply that (1) the CRS prediction method greatly improves estimates of cementation factors and permeability in carbonate, dolomite, and mixed siliciclastic rocks, (2) there are at least four distinct microporosity types in carbonate rocks, which have great impact on cementation factors and permeability, (3) nanopore geometry has a small impact on electrical flow properties in mudrocks where the main control on cementation factors is porosity, and (4) all sedimentary limestone and mixed carbonate-siliciclastic rocks have power law pore size distributions.

Microorganisms in desert rocks: the edge of life on Earth.

PubMed

Wierzchos, Jacek; de los Ríos, Asunción; Ascaso, Carmen

2012-12-01

This article reviews current knowledge on microbial communities inhabiting endolithic habitats in the arid and hyper-arid regions of our planet. In these extremely dry environments, the most common survival strategy is to colonize the interiors of rocks. This habitat provides thermal buffering, physical stability, and protection against incident UV radiation, excessive photosynthetically active radiation, and freeze-thaw events. Above all, through water retention in the rocks' network of pores and fissures, moisture is made available. Some authors have argued that dry environments pose the most extreme set of conditions faced by microorganisms. Microbial cells need to withstand the biochemical stresses created by the lack of water, along with temperature fluctuations and/or high salinity. In this review, we also address the variety of ways in which microorganisms deal with the lack of moisture in hyper-arid environments and point out the diversity of microorganisms that are able to cope with only the scarcest presence of water. Finally, we discuss the important clues to the history of life on Earth, and perhaps other places in our solar system, that have emerged from the study of extreme microbial ecosystems.

Isotope analysis of crystalline impact melt rocks from Apollo 16 stations 11 and 13, North Ray Crater

NASA Technical Reports Server (NTRS)

Reimold, W. U.; Nyquist, L. E.; Bansal, B. M.; Shih, C.-Y.; Weismann, H.; Wooden, J. L.; Mackinnon, I. D. R.

1985-01-01

The North Ray Crater Target Rock Consortium was formed to study a large number of rake samples collected at Apollo 16 stations 11 and 13 with comparative chemical, mineralogical, and chronological techniques in order to provide a larger data base for the discussion of lunar highland evolution in the vicinity of the Apollo 16 landing region. The present investigation is concerned with Rb-Sr and Sm-Nd isotopic analyses of a number of whole-rock samples of feldspathic microporhyritic (FM) impact melt, a sample type especially abundant among the North Ray crater (station 11) sample collection. Aspects of sample mineralogy and analytical procedures are discussed, taking into account FM impact melt rocks 6715 and 63538, intergranular impact melt rock 67775, subophitic impact melt rock 67747, subophitic impact melt rock 67559, and studies based on the utilization of electron microscopy and mass spectroscopy.

Rock sampling. [apparatus for controlling particle size

NASA Technical Reports Server (NTRS)

Blum, P. (Inventor)

1971-01-01

An apparatus for sampling rock and other brittle materials and for controlling resultant particle sizes is described. The device includes grinding means for cutting grooves in the rock surface and to provide a grouping of thin, shallow, parallel ridges and cutter means to reduce these ridges to a powder specimen. Collection means is provided for the powder. The invention relates to rock grinding and particularly to the sampling of rock specimens with good size control.

Nanocrystalline mirror-slip surfaces in calcite gouge sheared at sub-seismic slip rates

NASA Astrophysics Data System (ADS)

Verberne, B. A.; Plümper, O.; de Winter, D.; Niemeijer, A. R.; Spiers, C. J.

2013-12-01

If seismic-aseismic transitions in fault rocks are to be recognized from microstructures preserved in natural fault rocks, an understanding of the microphysical mechanisms that produce such microstructures is needed. We report on microstructures recovered from dry direct shear experiments on (simulated) dry calcite gouge, performed at 50 MPa normal stress, 18-150°C and low sliding velocities (0.1-10 μm/s). The mechanical data show a transition from velocity strengthening below ~80°C to velocity weakening slip at higher temperatures. We investigated both loose gouge fragments and thin sections, characterizing the microstructures at the mm- to nm-scales. All deformed samples split along a shear band fabric defined by mainly R1- and boundary shears. Viewed normal to the shear plane, these bands commonly showed shiny, elongate patches aligned, and striated, parallel to the shear direction. These patches were especially common in samples tested below 80°C, though shear band splitting was less well-developed above 80°C so that even if the shiny patches formed at higher temperature they were less frequently exposed. Scanning Electron Microscopy (SEM) applied to shiny patches formed in samples sheared at room temperature showed the presence of elongate, streaked out sub-micron-sized particles oriented parallel to the shear direction. Transmitted light optical microscopy of thin sections cut normal to the shear plane and parallel to the shear direction, combined with Focused Ion Beam (FIB) - SEM on loose gouge fragments, showed that the shiny surfaces correspond with shear bands characterized by extreme grain size reduction and sintered sub-micron-particles. Transmission Electron Microscopy (TEM) further revealed that the cores of the shear bands consist of nanocrystallites some 20 nm in size, with a Crystallographic Preferred Orientation (CPO). Our results demonstrate that mirror-like nanocrystalline slip zones can form in calcite gouge sheared at shallow crustal conditions at sub-seismic sliding velocities, in velocity strengthening as well as velocity weakening samples. This means that their presence cannot be used as a single diagnostic indicator for seismic slip in natural fault rocks. Our SEM and TEM observations suggest that, at room temperature, the frictional behavior of the shear bands is dominated by crystal plastic plus nanogranular flow mechanisms, rather than by brittle deformation processes - as inferred for frictional slip in some metals. We further suggest that it is the thermally activated nature of crystal plasticity that is responsible for the transition from velocity strengthening to velocity weakening slip that we observed at ~80°C. The inferred mechanism has important implications for understanding both the depth range of seismicity and the seismic cycle in tectonically-active carbonate terrains.

Obtaining higher-accuracy estimates of water-rich rocks and water-poor sand dunes on Mars in active neutron experiments

NASA Astrophysics Data System (ADS)

Gabriel, T. S. J.; Hardgrove, C.; Litvak, M. L.; Nowicki, S.; Mitrofanov, I. G.; Boynton, W. V.; Fedosov, F.; Golovin, D.; Jun, I.; Mischna, M.; Tate, C. G.; Moersch, J.; Harshman, K.; Kozyrev, A.; Malakhov, A. V.; Mokrousov, M.; Nikiforov, S.; Sanin, A. B.; Vostrukhin, A.; Thompson, L. M.

2017-12-01

The Dynamic Albedo of Neutrons (DAN) experiment on the Mars Science Laboratory Curiosity Rover delivers high-energy (14.1 MeV) pulses of neutrons into the surface when operating in "active" mode. Neutrons are moderated in the subsurface and return to two detectors to provide a time-of-flight profile in 64 time-bins in epithermal and thermal energy ranges. Results are compared to simulations of the experiment in the Monte Carlo N-Particle Transport Code where several aspects are modeled including the DAN detectors, neutron source, rover components, and underlying rock. Models can be improved by increasing the fidelity of the rock geochemistry as informed by instruments including the Alpha Particle X-Ray Spectrometer (APXS). Furthermore, increasing the fidelity of the rock morphology in models is enabled by the suite of imaging instruments on the rover.To rapidly interpret DAN data a set of pre-simulated generic rock density and bulk geochemistry models are compared to several DAN active observations. While, to first order, this methodology provides an indication of significant geochemical changes in the subsurface, higher-fidelity models should be used to provide accurate constraints on water content, depth of geologic layers, or abundance of neutron absorbers. For example, in high-silicon, low-iron rocks observed along the rover's traverse, generic models can differ by several wt%H2O from models that use APXS measurements of nearby drill samples. Accurate measurements of high-silicon targets are necessary in outlining the extent of aqueous alteration and hydrothermal activity in Gale Crater. Additionally, we find that for DAN active experiments over sand dunes best-fit models can differ by greater than 0.5 wt%HO when the upper layer density is reduced by 0.6 g/cm3 to account for the low-bulk density of sand. In areas where the rock geochemistry differs little from generic models the difference in results is expectedly less disparate. We report refined wt%HO values for high-silicon, aqueously-altered rock and comparatively dry sand dunes along the rover traverse. We also outline the methodology for providing accurate geochemical and morphological constraints using DAN active measurements.

Estimates of olivine-basaltic melt electrical conductivity using a digital rock physics approach

NASA Astrophysics Data System (ADS)

Miller, Kevin J.; Montési, Laurent G. J.; Zhu, Wen-lu

2015-12-01

Estimates of melt content beneath fast-spreading mid-ocean ridges inferred from magnetotelluric tomography (MT) vary between 0.01 and 0.10. Much of this variation may stem from a lack of understanding of how the grain-scale melt geometry influences the bulk electrical conductivity of a partially molten rock, especially at low melt fraction. We compute bulk electrical conductivity of olivine-basalt aggregates over 0.02 to 0.20 melt fraction by simulating electric current in experimentally obtained partially molten geometries. Olivine-basalt aggregates were synthesized by hot-pressing San Carlos olivine and high-alumina basalt in a solid-medium piston-cylinder apparatus. Run conditions for experimental charges were 1.5 GPa and 1350 °C. Upon completion, charges were quenched and cored. Samples were imaged using synchrotron X-ray micro-computed tomography (μ-CT). The resulting high-resolution, 3-dimensional (3-D) image of the melt distribution constitutes a digital rock sample, on which numerical simulations were conducted to estimate material properties. To compute bulk electrical conductivity, we simulated a direct current measurement by solving the current continuity equation, assuming electrical conductivities for olivine and melt. An application of Ohm's Law yields the bulk electrical conductivity of the partially molten region. The bulk electrical conductivity values for nominally dry materials follow a power-law relationship σbulk = Cσmeltϕm with fit parameters m = 1.3 ± 0.3 and C = 0.66 ± 0.06. Laminar fluid flow simulations were conducted on the same partially molten geometries to obtain permeability, and the respective pathways for electrical current and fluid flow over the same melt geometry were compared. Our results indicate that the pathways for flow fluid are different from those for electric current. Electrical tortuosity is lower than fluid flow tortuosity. The simulation results are compared to existing experimental data, and the potential influence of volatiles and melt films on electrical conductivity of partially molten rocks is discussed.

Tectonic setting and metallogenesis of volcanogenic massive sulfide deposits in the Bonnifield Mining District, Northern Alaska Range: Chapter B in Recent U.S. Geological Survey studies in the Tintina Gold Province, Alaska, United States, and Yukon, Canada--results of a 5-year project

USGS Publications Warehouse

Dusel-Bacon, Cynthia; Aleinikoff, John N.; Premo, Wayne R.; Paradis, Suzanne; Lohr-Schmidt, Ilana; Gough, Larry P.; Day, Warren C.

2007-01-01

This paper summarizes the results of field and laboratory investigations, including whole-rock geochemistry and radiogenic isotopes, of outcrop and drill core samples from volcanogenic massive sulfide (VMS) deposits and associated metaigneous rocks in the Wood River area of the Bonnifield mining district, northern Alaska Range (see fig. 1 of Editors’ Preface and Overview). U-Pb zircon igneous crystallization ages from felsic rocks indicate a prolonged period of Late Devonian to Early Mississippian (373±3 to 357±4 million years before present, or Ma) magmatism. This magmatism occurred in a basinal setting along the ancient Pacific margin of North America. The siliceous and carbonaceous compositions of metasedimentary rocks, Precambrian model ages based on U-Pb dating of zircon and neodymium ages, and for some units, radiogenic neodymium isotopic compositions and whole-rock trace-element ratios similar to those of continental crust are evidence for this setting. Red Mountain (also known as Dry Creek) and WTF, two of the largest VMS deposits, are hosted in peralkaline metarhyolite of the Mystic Creek Member of the Totatlanika Schist. The Mystic Creek Member is distinctive in having high concentrations of high-field-strength elements (HFSE) and rare-earth elements (REE), indicative of formation in a within-plate (extensional) setting. Mystic Creek metarhyolite is associated with alkalic, within-plate basalt of the Chute Creek Member; neodymium isotopic data indicate an enriched mantle component for both members of this bimodal (rhyolite-basalt) suite. Anderson Mountain, the other significant VMS deposit, is hosted by the Wood River assemblage. Metaigneous rocks in the Wood River assemblage span a wide compositional range, including andesitic rocks, which are characteristic of arc volcanism. Our data suggest that the Mystic Creek Member likely formed in an extensional, back-arc basin that was associated with an outboard continental-margin volcanic arc that included rocks of the Wood River assemblage. We suggest that elevated HFSE and REE trace-element contents of metavolcanic rocks, whose major-element composition may have been altered, are an important prospecting tool for rocks of VMS deposit potential in east-central Alaska.

An Analysis of the Seismic Source Characteristics of Explosions in Low-Coupling Dry Porous Media

DTIC Science & Technology

2011-09-29

Semipalatinsk Test Site (Shagan, Degelen and Konystan Testing Areas) and in Salt at the Former Soviet Azgir Test Site ...to be applicable to all underground nuclear explosions conducted in various hard rock media at the former Soviet Semipalatinsk test site , as well as...in Hard Rock at the Former Soviet Semipalatinsk Test Site (Shagan, Degelen and Konystan Testing Areas) and in Salt at the Former Soviet Azgir Test

The Evolution of Elastic Moduli With Increasing Crack Damage During Cyclic Stressing of Etna Basalt

NASA Astrophysics Data System (ADS)

Heap, M. J.; Meredith, P. G.; Vinciguerra, S.; Boon, S. A.

2007-12-01

Volcanic edifices, such as Mt. Etna volcano, are commonly subject to cycles of pressurization and depressurization over extended periods of time due to repeated episodes of magma emplacement from deep reservoirs to shallow depths. Such repeated episodes of deformation can lead to an increase in the level of crack damage within the rocks of the edifice, and hence changes in their elastic properties. Importantly, a number of volcano monitoring techniques, such as seismic tomography and ground deformation modeling, rely on accurate knowledge of elastic properties. However, the effect of cyclic stressing on mechanical and elastic properties of volcanic rock remains unclear. To this end, we report results of changes in elastic moduli from stress-cycling experiments on samples of extrusive basalt from Mount Etna, Italy. The basalt contains an extensive pre-existing network of isotropic, interconnected microcracks caused by cooling. Both oven-dry and water-saturated samples were initially loaded to 20 MPa at a constant rate and then unloaded to 8 MPa. Samples were then sequentially reloaded and unloaded at the same rate with the peak stress in each subsequent cycle increased by 10 MPa. Stress-cycling was continued until each sample failed. Results from oven-dry samples showed a gradual reduction in sample stiffness with each increasing stress cycle that resulted in a total decrease in Young's modulus of approximately 30% and an increase in Poisson's ratio of approximately 60%. Results from water-saturated samples showed an almost identical trend. These changes in moduli are attributed to the growth of new cracks in each stress cycle and, hence, an increase in the total crack density. This is supported by the observation of increased acoustic emission (micro-seismic) output in each cycle. We also observed the Kaiser stress-memory effect, where acoustic emission on each cycle only occurs when the maximum stress in the previous cycle has been exceeded. During the deformation history of volcanic edifices, however, the stress in each pressurization cycle may not always exceed that of the previous cycle. In order to better understand this more realistic situation, we also report results from cyclic stressing experiments where the peak stress in each cycle has been randomly selected to be either higher or lower than that of the previous cycle. In this case we observed a more complex manifestation of the Kaiser effect, where AE output in any cycle was only observed when the stress in that cycle exceeded the maximum stress on any previous cycle.

Preliminary examination of lunar samples from apollo 14.

PubMed

1971-08-20

The major findings of the preliminary examination of the lunar samples are as follows: 1) The samples from Fra Mauro base may be contrasted with those from Tranquillity base and the Ocean of Storms in that about half the Apollo 11 samples consist of basaltic rocks, and all but three Apollo 12 rocks are basaltic, whereas in the Apollo 14 samples only two rocks of the 33 rocks over 50 grams have basaltic textures. The samples from Fra Mauro base consist largely of fragmental rocks containing clasts of diverse lithologies and histories. Generally the rocks differ modally from earlier lunar samples in that they contain more plagioclase and contain orthopyroxene. 2) The Apollo 14 samples differ chemically from earlier lunar rocks and from their closest meteorite and terrestrial analogs. The lunar material closest in composition is the KREEP component (potassium, rare earth elements, phosphorus), "norite," "mottled gray fragments" (9) from the soil samples (in particular, sample 12033) from the Apollo 12 site, and the dark portion of rock 12013 (10). The Apollo 14 material is richer in titanium, iron, magnesium, and silicon than the Surveyor 7 material, the only lunar highlands material directly analyzed (11). The rocks also differ from the mare basalts, having much lower contents of iron, titanium, manganese, chromium, and scandium and higher contents of silicon, aluminum, zirconium, potassium, uranium, thorium, barium, rubidium, sodium, niobium, lithium, and lanthanum. The ratios of potassium to uranium are lower than those of terrestrial rocks and similar to those of earlier lunar samples. 3) The chemical composition of the soil closely resembles that of the fragmental rocks and the large basaltic rock (sample 14310) except that some elements (potassium, lanthanum, ytterbium, and barium) may be somewhat depleted in the soil with respect to the average rock composition. 4) Rocks display characteristic surface features of lunar material (impact microcraters, rounding) and shock effects similar to those observed in rocks and soil from the Apollo 11 and Apollo 12 missions. The rocks show no evidence of exposure to water, and their content of metallic iron suggests that they, like the Apollo 11 and Apollo 12 material, were formed and have remained in an environment with low oxygen activity. 5) The concentration of solar windimplanted material in the soil is large, as was the case for Apollo 11 and Apollo 12 soil. However, unlike previous fragmental rocks, Apollo 14 fragmental rocks possess solar wind contents ranging from approximately that of the soil to essentially zero, with most rocks investigated falling toward one extreme of this range. A positive correlation appears to exist between the solar wind components, carbon, and (20)Ne, of fragmental rocks and their friability (Fig. 12). 6) Carbon contents lie within the range of carbon contents for Apollo 11 and Apollo 12 samples. 7) Four fragmental rocks show surface exposure times (10 x 10(6) to 20 x 10(6) years) about an order of magnitude less than typical exposure times of Apollo 11 and Apollo 12 rocks. 8) A much broader range of soil mechanics properties was encountered at the Apollo 14 site than has been observed at the Apollo 11, Apollo 12, and Surveyor landing sites. At different points along the traverses of the Apollo 14 mission, lesser cohesion, coarser grain size, and greater resistance to penetration was found than at the Apollo 11 and Apollo 12 sites. These variations are indicative of a very complex, heterogeneous deposit. The soils are more poorly sorted, but the range of grain size is similar to those of the Apollo 11 and Apollo 12 soils. 9) No evidence of biological material has been found in the samples to date.

Effect on human health of the arsenic pollution and hydrogeochemistry of the Yazır Lake wetland (Çavdır-Burdur/Turkey).

PubMed

Varol, Simge; Köse, İlknur

2018-06-01

In this study, the physicochemical parameters, major ions and arsenic (As) contents of water resources in the Yazır lake wetland, were evaluated. In addition, water resources in this region were investigated from the point of water quality and health risk assessment. Thirty water samples were collected from the area in dry and wet seasons. Ca-Mg-HCO 3 and Ca-HCO 3 were the dominant water types. The Gibbs diagram suggests that most of the samples fall in rock-dominance zone, which indicates the groundwater interaction between rock chemistry. When compared to drinking water guidelines established by World Health Organization and Turkey, much greater attention should be paid to As, Fe, and Mn through varied chemicals above the critical values. According to the pH-ORP diagram, the predominant species is arsenate (H 2 AsO 4 -2 ). The high concentrations of As in the surface water and groundwater are related to oxidative and reductive dissolution reaction of Fe and Mn hydroxides within the Kızılcadağ ophiolite and melange. In addition, the seasonal changes in As concentrations depend on the increase in pH of water samples. The major toxic and carcinogenic chemical within water samples is As for groundwater and surface water. From the results of hazard index, it is verified that As which is taken by ingestion of water was the main contaminant, and toxic human risk in the study area. The obtained results will help define strategies for As problems in the water resources in future.

Seismic attenuation and scattering tomography of rock samples using stochastic wavefields: linking seismology, volcanology, and rock physics.

NASA Astrophysics Data System (ADS)

Fazio, Marco; De Siena, Luca; Benson, Phillip

2016-04-01

Seismic attenuation and scattering are two attributes that can be linked with porosity and permeability in laboratory experiments. When measuring these two quantities using seismic waveforms recorder at lithospheric and volcanic scales the areas of highest heterogeneity, as batches of melt and zones of high deformation, produce anomalous values of the measured quantities, the seismic quality factor and scattering coefficient. When employed as indicators of heterogeneity and absorption in volcanic areas these anomalous effects become strong indicators of magma accumulation and tectonic boundaries, shaping magmatic chambers and conduit systems. We perform attenuation and scattering measurements and imaging using seismic waveforms produced in laboratory experiments, at frequencies ranging between the kHz and MHz. As attenuation and scattering are measured from the shape of the envelopes, disregarding phases, we are able to connect the observations with the micro fracturing and petrological quantities previously measured on the sample. Connecting the imaging of dry and saturated samples via these novel attributes with the burst of low-period events with increasing saturation and deformation is a challenge. Its solution could plant the seed for better relating attenuation and scattering tomography measurements to the presence of fluids and gas, therefore creating a novel path for reliable porosity and permeability tomography. In particular for volcanoes, being able to relate attenuation/scattering measurements with low-period micro seismicity could deliver new data to settle the debate about if both source and medium can produce seismic resonance.

Composition and structure of the Chironomidae (Insecta: Diptera) community associated with bryophytes in a first-order stream in the Atlantic forest, Brazil.

PubMed

Rosa, B F J V; Dias-Silva, M V D; Alves, R G

2013-02-01

This study describes the structure of the Chironomidae community associated with bryophytes in a first-order stream located in a biological reserve of the Atlantic Forest, during two seasons. Samples of bryophytes adhered to rocks along a 100-m stretch of the stream were removed with a metal blade, and 200-mL pots were filled with the samples. The numerical density (individuals per gram of dry weight), Shannon's diversity index, Pielou's evenness index, the dominance index (DI), and estimated richness were calculated for each collection period (dry and rainy). Linear regression analysis was employed to test the existence of a correlation between rainfall and the individual's density and richness. The high numerical density and richness of Chironomidae taxa observed are probably related to the peculiar conditions of the bryophyte habitat. The retention of larvae during periods of higher rainfall contributed to the high density and richness of Chironomidae larvae. The rarefaction analysis showed higher richness in the rainy season related to the greater retention of food particles. The data from this study show that bryophytes provide stable habitats for the colonization by and refuge of Chironomidae larvae, mainly under conductions of faster water flow and higher precipitation.

Hydrologic analysis of the U.S. Bureau of Mines' underground oil-shale research-facility site, Piceance Creek Basin, Rio Blanco County, Colorado

USGS Publications Warehouse

Dale, R.H.; Weeks, John B.

1978-01-01

The U.S. Bureau of Mines plans to develop an underground oil-shale research facility near the center of Piceance Creek basin in Colorado. The oil-shale zone, which is to be penetrated by a shaft, is overlain by 1,400 feet of sedimentary rocks, primarily sandstone and marlstone, consisting of two aquifers separated by a confining layer. Three test holes were drilled by the U.S. Bureau of Mines to obtain samples of the oil shale, and to test the hydraulic properties of the two aquifers. The data collected during construction of the test holes were used to update an existing ground-water-flow computer model. The model was used to estimate the maximum amount of water that would have to be pumped to dewater the shaft during its construction. It is estimated that it would be necessary to pump as much as 3,080 gallons per minute to keep the shaft dry. Disposal of waste water and rock are the principal hydrologic problems associated with constructing the shaft. (Woodard-USGS)

Drying and color characteristics of coriander foliage using convective thin-layer and microwave drying.

PubMed

Shaw, Mark; Meda, Venkatesh; Tabil, Lope; Opoku, Anthony

2007-01-01

Heat sensitive properties (aromatic, medicinal, color) provide herbs and spices with their high market value. In order to prevent extreme loss of heat sensitive properties when drying herbs, they are normally dried at low temperatures for longer periods of time to preserve these sensory properties. High energy consumption often results from drying herbs over a long period. Coriander (Coriandrum sativum L., Umbelliferae) was dehydrated in two different drying units (thin layer convection and microwave dryers) in order to compare the drying and final product quality (color) characteristics. Microwave drying of the coriander foliage was faster than convective drying. The entire drying process took place in the falling rate period for both microwave and convective dried samples. The drying rate for the microwave dried samples ranged from 42.3 to 48.2% db/min and that of the convective dried samples ranged from 7.1 to 12.5% db/min. The fresh sample color had the lowest L value at 26.83 with higher L values for all dried samples. The results show that convective thin layer dried coriander samples exhibited a significantly greater color change than microwave dried coriander samples. The color change index values for the microwave dried samples ranged from 2.67 to 3.27 and that of the convective dried samples varied from 4.59 to 6.58.

Introduction to the Apollo collections. Part 1: Lunar igneous rocks

NASA Technical Reports Server (NTRS)

Mcgee, P. E.; Warner, J. L.; Simonds, C. H.

1977-01-01

The basic petrographic, chemical, and age data is presented for a representative suite of igneous rocks gathered during the six Apollo missions. Tables are given for 69 samples: 32 igneous rocks and 37 impactites (breccias). A description is given of 26 basalts, four plutonic rocks, and two pyroclastic samples. The textural-mineralogic name assigned each sample is included.

Hydrogeochemical and stream sediment reconnaissance basic data report for Williams NTMS quadrangle, Arizona

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

Wagoner, J.L.

Wet and dry sediments were collected throughout the 18,500-km/sup 2/arid-to-semiarid region and water samples at available streams, springs, and wells. Samples were collected between August 1977 and January 1978. Results of neutron activation analyses of uranium and trace elements and other field and laboratory analyses are presented in tabular hardcopy and microfiche format. The report includes six full-size overlays for use with the Williams NTMS 1:250,000 quadrangle. Sediment samples are divided into five general groups according to the source rock from which the sediment was derived. Background uranium concentrations for the quadrangle are relatively low, ranging from 1.91 to 2.40more » ppM, with the highest associated with the Precambrian igneous and metamorphic complexes of the Basin and Range province. Uranium correlates best with the rare-earth elements and iron, scandium, titanium, and manganese. Known uranium occurrences are not readily identified by the stream sediment data.« less

Data Validation Package September 2016 Groundwater and Surface Water Sampling at the Slick Rock, Colorado, Processing Sites January 2017

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

Traub, David; Nguyen, Jason

The Slick Rock, Colorado, Processing Sites are referred to as the Slick Rock West Processing Site (SRK05) and the Slick Rock East Processing Site (SRK06). This annual event involved sampling both sites for a total of 16 monitoring wells and 6 surface water locations as required by the 2006 Draft Final Ground Water Compliance Action Plan for the Slick Rock, Colorado, Processing Sites (GCAP). A domestic well was also sampled at a property adjacent to the Slick Rock East site at the request of the landowner.

The Paradox of a Wet (High H2O) and Dry (Low H2O/Ce) Mantle: High Water Concentrations in Mantle Garnet Pyroxenites from Hawaii

NASA Technical Reports Server (NTRS)

Peslier, Anne H.; Bizimis, Michael

2013-01-01

Water dissolved as trace amounts in anhydrous minerals has a large influence on the melting behavior and physical properties of the mantle. The water concentration of the oceanic mantle is inferred from the analyses of Mid-Ocean Ridge Basalt (MORB) and Oceanic Island Basalt (OIB). but there is little data from actual mantle samples. Moreover, enriched mineralogies (pyroxenites, eclogites) are thought as important sources of heterogeneity in the mantle, but their water concentrations and their effect on the water budget and cycling in the mantle are virtually unknown. Here, we analyzed by FTIR water in garnet clinopyroxenite xenoliths from Salt Lake Crater, Oahu, Hawaii. These pyroxenites are high-pressure (>20kb) crystal fractionates from alkalic melts. The clinopyroxenes (cpx) have 260 to 576 ppm wt H2O, with the least differentiated samples (Mg#>0.8) in the 400-500 ppm range. Orthopyroxene (opx) contain 117-265 ppm H2O, about half of that of cpx, consistent with other natural sample studies, but lower than cpx/opx equilibrium from experimental data. The pyroxenite cpx and opx H2O concentrations are at the high-end of on-and off-craton peridotite xenolith concentrations and those of Hawaiian spinel peridotites. In contrast, garnet has extremely low water contents (<5ppm H2O). There is no correlation between H2O in cpx and lithophile element concentrations. Phlogopite is present in some samples, and its modal abundance shows a positive correlation in Mg# with cpx, implying equilibrium. However, there is no correlation between H2O concentrations and or the presence of phlogopite. These data imply that cpx and opx may be at water saturation, far lower than experimental data suggest. Reconstructed bulk rock pyroxenite H2O ranges from 200-460 ppm (average 331 +/- 75 ppm), 2 to 8 times higher than H2O estimates for the MORB source (50-200 ppm), but in the range of E-MORB, OIB and the source of rejuvenated Hawaiian magmas. The average bulk rock pyroxenite H2O/Ce is 69 +/-35, lower than estimates of the MORB source (approx 150) or FOZO, C (200-250) mantle component, but consistent with "dry" EM sources (<100). These data suggest that a metasomatized, refertilized oceanic lithosphere that contains pyroxenitic veins (e.g. the lower part of an oceanic plate, where ascending melts can become trapped and crystallize), will have both higher water concentrations and low H2O/Ce, and may contribute to EM-type OIB sources, like that of Samoa basalts. Therefore, a low H2O/Ce mantle source may not necessarily be "dry".

[Temporal-spatial Variation and Source Identification of Hydro-chemical Characteristics in Shima River Catchment, Dongguan City].

PubMed

Gao, Lei; Chen, Jian-yao; Wang, Jiang; Ke, Zhi-ting; Zhu, Ai-ping; Xu, Kai

2015-05-01

Shima River catchment is of strategic importance to urban water supply in Dongjiang portable water source area. To investigate the hydro-chemical characteristics of Shima River, 39 river water samples were collected in February, June and November, 2012 to analyze the major ions (K+, Na+, Ca2+, Mg2+, Cl-, SO4(2-) , HCO3-) and nutritive salts (PO4(3-), NO3- and NH4+) and to discuss the temporal-spatial variation and controlling factors of hydro-chemical composition, relative sources identification of varied ions was performed as well. The results showed that the hydro-chemical composition exhibited significant differences in different periods. The average concentration of total dissolved solid ( TDS) and nutritive salts in different investigated periods followed the decreasing order of November > February > June. The dominant anion of Shima River was HCO3-, and Na+ + K+ were the major cations in February and November which were changed to Ca2+ in June, the hydro-chemical types were determined as HCO(3-)-Na+ and HCO(3-)- Ca2+ in dry (February and November) and rainy (June) seasons, respectively. Spatial variations of concentration of nutritive salts were mainly affected by the discharges of N- and P-containing waste water resulted from human activities. The ratio between N and P of water sample (R7) was 18.4:1 which boosted the "crazy growth" of phytoplankton and led to severe eutrophication. According to Gibbs distribution of water samples, dissolution of hydatogenic rocks was the primary factor to control the major cations of river water in dry season, however, the hydro-chemical composition was significantly affected by the combination of hydatogenic and carbonate rocks in rainy season. The deposition of sea-salts contributed less to chemical substances in river. Correlation analysis revealed that K+, Na+, Mg2+, Cl- and SO4(2-) were partly derived from the application of fertilizer and the discharge of industrial effluent; Waste water of poultry feeding and sanitary wastewater transported large quantities of NH(4+)-N, PO4(3-)-P and NO(3-)-N into the river.

Zinc accumulation by the slime mold Fuligo septica (L.) Wiggers in the former Soviet Union and North Korea.

PubMed

Zhulidov, Daniel A; Robarts, Richard D; Zhulidov, Alexander V; Zhulidova, Olga V; Markelov, Danila A; Rusanov, Viktor A; Headley, John V

2002-01-01

Samples of the slime mold Fuligo septica (L.) Wiggers were collected from an ecologically diverse selection of sites across the former USSR and in North Korea to determine their Zn concentrations. Plasmodia were collected from trees, rocks, soils, the walls of buildings and a variety of other materials and structures from 1990 to 1996. The biomass collected ranged from 305 to 968 mg, whereas Zn concentrations in plasmodia of F. septica ranged from 8400 to 23,000 mg kg(-1) dry wt. (mean and standard error = 14,200 +/- 860 mg kg(-1) dry wt.). No clear trend as to which areas produced F. septica with the highest Zn concentrations was discernable. Nor was it possible to identify any particular substrate on which F. septica grew that produced noticeably high Zn concentrations. For example, forest litter on which F. septica was found had Zn concentrations of only 25 to 130 mg kg(-1) dry wt. Our data confirm the only other study showing hyperaccumulation of Zn in F. septica, which was carried out in Finland. This ability seems to be unique to this species, but how or why it does this, or why such high Zn concentrations are not toxic to F. septica, are questions requiring future research.

Role of Water Activity on Intergranular Transport at High Pressure

NASA Astrophysics Data System (ADS)

Gasc, J.; Brunet, F.; Brantut, N.; Corvisier, J.; Findling, N.; Verlaguet, A.; Lathe, C.

2016-12-01

The kinetics of the reaction Ca(OH)2 + MgCO3 = CaCO3 + Mg(OH)2 were investigated at a pressure of 1.8 GPa and temperatures of 120-550°C, using synchrotron X-ray diffraction and analysis of reaction rims on recovered samples. Comparable reaction kinetics were obtained under water saturated ( 10 wt.%), intermediate (0.1-1 wt.%) and dry conditions at 150, 400 and 550°C, respectively, where, in the latter case, water activity was buffered below one (no free water). At a given temperature, these gaps imply differences of several orders of magnitude in terms of reaction kinetics. Microscopy analysis shows that intergranular transport of Ca controls the reaction progress. Grain boundary diffusivities were retrieved from measurements of reaction rim widths on recovered samples. In addition, an innovative reaction rim growth model was developed to simulate and fit kinetic data. The diffusion values thus obtained show that both dry and intermediate datasets are in fact consistent with a water saturated intergranular medium with different levels of connectivity. Diffusivity of Ca in the CaCO3 + Mg(OH)2 rims is found to be much larger than that of Mg in enstatite rims, which emphasizes the prominent role of interactions between diffusing species and mineral surfaces on diffusion. We suggest that diffusivity of major species (Mg, Ca) in low-porosity metamorphic rocks is not only water-content dependent but also strongly depends on the interaction between diffusing species and mineral surfaces. This parameter, which will vary from one rock-type to the other, needs to be considered when extrapolating (P,T,t, xH2O) laboratory diffusion data to metamorphic processes. The present study, along with previous data from the literature, will help quantify the tremendous effect of small water content variations, i.e., within the 0-1 wt. % range, on intergranular transport and reaction kinetics (Gasc et al., J. Pet., In press).

The Usability of Rock-Like Materials for Numerical Studies on Rocks

NASA Astrophysics Data System (ADS)

Zengin, Enes; Abiddin Erguler, Zeynal

2017-04-01

The approaches of synthetic rock material and mass are widely used by many researchers for understanding the failure behavior of different rocks. In order to model the failure behavior of rock material, researchers take advantageous of different techniques and software. But, the majority of all these instruments are based on distinct element method (DEM). For modeling the failure behavior of rocks, and so to create a fundamental synthetic rock material model, it is required to perform related laboratory experiments for providing strength parameters. In modelling studies, model calibration processes are performed by using parameters of intact rocks such as porosity, grain size, modulus of elasticity and Poisson ratio. In some cases, it can be difficult or even impossible to acquire representative rock samples for laboratory experiments from heavily jointed rock masses and vuggy rocks. Considering this limitation, in this study, it was aimed to investigate the applicability of rock-like material (e.g. concrete) to understand and model the failure behavior of rock materials having complex inherent structures. For this purpose, concrete samples having a mixture of %65 cement dust and %35 water were utilized. Accordingly, intact concrete samples representing rocks were prepared in laboratory conditions and their physical properties such as porosity, pore size and density etc. were determined. In addition, to acquire the mechanical parameters of concrete samples, uniaxial compressive strength (UCS) tests were also performed by simultaneously measuring strain during testing. The measured physical and mechanical properties of these extracted concrete samples were used to create synthetic material and then uniaxial compressive tests were modeled and performed by using two dimensional discontinuum program known as Particle Flow Code (PFC2D). After modeling studies in PFC2D, approximately similar failure mechanism and testing results were achieved from both experimental and artificial simulations. The results obtained from these laboratory tests and modelling studies were compared with the other researcher's studies in respect to failure mechanism of different type of rocks. It can be concluded that there is similar failure mechanism between concrete and rock materials. Therefore, the results obtained from concrete samples that would be prepared at different porosity and pore sizes can be used in future studies in selection micro-mechanical and physical properties to constitute synthetic rock materials for understanding failure mechanism of rocks having complex inherent structures such as vuggy rocks or heavily jointed rock masses.

Rock Around the World: International Outreach for Scientific Education Using Infrared Spectroscopy

NASA Astrophysics Data System (ADS)

Rogers, L. D.; Klug, S. L.; Christensen, P. R.; Rogers, T. A.; Daub, G.

2005-12-01

Since the creation of the Rock Around the World (RATW) program in January 2004, we have received 6,861 (to date) rocks from children and adults alike from around the world. RATW is an educational outreach device to inspire and teach children about science. In addition, the accumulation of almost 7,000 rock samples has exponentially expanded the Arizona State University earth-based rock library into a large collection of samples useful for scientific investigation of Earth and Mars. This library currently supports research that is being conducted by the Mars Global Surveyor Thermal Emission Spectrometer (TES), the Mars Odyssey Thermal Emission Imaging System (THEMIS) and the two Mini-Thermal Emission Spectrometer (Mini-TES) instruments that are onboard the Mars Exploration Rovers. Currently, we have 3 undergraduate students working on the RATW project. As each rock sample arrives, appropriate information that was received with the sample is entered into our web-based RATW database. The information received with the rock sample is directly input into the RATW website. The information is publicly available for each sample at http://ratw.asu.edu. The sample is photographed, and then sent to the spectrometer for analysis. Once the spectrum is taken, calibration is performed. Then the sample is filed away in our rock archive room. Our website has several interactive tools which enhance the learning process. These tools include an interactive world map where the visitor can click on a rock location and preview all of the rocks sent from that geographical area of the world. In addition RATW has also put four virtual mineral libraries online. This enables any visitor to the RATW website to deconvolve or "unmix" their spectrum to see the mineral composition, using the same techniques that scientists use on the TES, THEMIS, and mini-TES data. The 6,861 rock samples we have received have been very geographically widespread. Participants have sent rocks from such places as Greenland, India, Switzerland and the Falkland Islands. We have received submissions that have included maps, drawings, pictures, stories, GPS readings and scientific literature and research about their rock sample and collection area. The number of RATW participants, and the enthusiasm with which they have participated, has shown that educational and scientific programs in Earth and Planetary Science draw worldwide interest among students and adults alike.

Polygon/Cracked Sedimentary Rock

NASA Technical Reports Server (NTRS)

2004-01-01

4 December 2004 Exposures of sedimentary rock are quite common on the surface of Mars. Less common, but found in many craters in the regions north and northwest of the giant basin, Hellas, are sedimentary rocks with distinct polygonal cracks in them. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example from the floor of an unnamed crater near 21.0oS, 311.9oW. Such cracks might have formed by desiccation as an ancient lake dried up, or they might be related to ground ice freeze/thaw cycles or some other stresses placed on the original sediment or the rock after it became lithified. The 300 meter scale bar is about 328 yards long. The scene is illuminated by sunlight from the upper left.

The Antarctic cold desert and the search for traces of life on Mars.

PubMed

Friedmann, E I

1986-01-01

The cryptoendolithic microorganisms that live inside rocks in the frigid Ross Desert of Antarctica can serve as a terrestrial model for what may have happened to life forms on Mars when the planet became dry and cold. Trace fossils of microbial rock colonization exist in Antarctica, and similar structures could have formed on Mars. In some respects, such trace fossils could be an easier target for life-detection systems than fossils of cellular structures.

The Antarctic cold desert and the search for traces of life on Mars

NASA Technical Reports Server (NTRS)

Friedmann, E. I.

1986-01-01

The cryptoendolithic microoganisms that live inside rocks in the frigid Ross Desert of Antarctica can serve as a terrestrial model for what may have happened to life forms on Mars when the planet became dry and cold. Trace fossils of microbial rock colonization exist in Antarctica, and similar structures could have formed on Mars. In some respects, such trace fossils could be an easier target for life-detection systems than fossils of cellular structures.

Petrography and geochemistry of selected lignite beds in the Gibbons Creek mine (Manning Formation, Jackson Group, Paleocene) of east-central Texas

USGS Publications Warehouse

Warwick, Peter D.; Crowley, Sharon S.; Ruppert, Leslie F.; Pontolillo, James

1997-01-01

This study examined the petrographic and geochemical characteristics of two lignite beds (3500 and 4500 beds, Manning Formation, Jackson Group, Eocene) that are mined at the Gibbons Creek mine in east-central Texas. The purpose of the study was to identify the relations among sample ash yield, coal petrography, and trace-element concentrations in lignite and adjoining rock layers of the Gibbons Creek mine. Particular interest was given to the distribution of 12 environmentally sensitive trace elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) that have been identified as potentially hazardous air pollutants (HAPs) in the United States Clean Air Act Amendments of 1990. Eleven lignite, floor, and rock parting samples were collected from incremental channel samples of the 3500 and 4500 beds that were exposed in a highwall of pit A3 at the Gibbons Creek mine. Short proximate and ultimate and forms of sulfur analyses were performed on all lignite samples, and lignite and rock samples were analyzed for 60 major, minor and trace elements. Representative splits of all lignite samples were ground and cast into pellets, and polished for petrographic analyses in blue-light fluorescence and reflected white light to determine liptinite, inertinite, and huminite maceral group percentages. The following observations summarize our results and conclusions about the geochemistry, petrography, and sedimentology of the 3500 and 4500 beds of the Gibbons Creek lignite deposit: (1) Weighted average dry (db) ash yield for the two beds is 29.7%, average total sulfur content is 2.6%, and average calorific value is 7832 Btu (18.22 MJ/kg). Ash yields are greatest in the lower bench (59.33% db) of the 3500 bed and in the upper bench of the 4500 bed (74.61% db). (2) For lignite samples (on a whole-coal basis), the distributions of two of the HAPs (Pb and Sb) are positively related to ash yield, probably indicating an inorganic affinity for these elements. By using cluster analysis we found that Be and Cd were poorly associated with ash yield, indicating a possible organic affinity, and that Ni, Se, Hg, U, and Pb cluster with most of the rare-earth elements. (3) The dominance of the crypto-eugelinite maceral subgroup over the crypto-humotelinite subgroup suggests that all Gibbons Creek lignites were subjected to peat-forming conditions (either biogenic or chemical) conducive to the degradation of wood cellular material into matrix gels, or that original plant material was not very woody and was prone to formation of matrix gels. The latter idea is supported by pollen studies of Gibbons Creek lignite beds; results indicate that the peat was derived in part from marsh plants low in wood tissue. (4) The occurrence of siliceous sponge spicules in the lower benches of the 3500 bed suggests the original peat in this part of the bed was deposited in standing, fresh water. (5) The petrographic data indicate that the upper sample interval of the 3500 bed contains more inertinite (3%) than the other samples studied. Increases in inertinite content in the upper part of the 3500 bed may have been associated with alteration of the peat by acids derived from the volcanic ash or could have been caused by fire, oxidation and drying, or biologic alteration of the peat in the paleo-mire.

Uranium in NIMROC standard igneous rock samples

NASA Technical Reports Server (NTRS)

Rowe, M. W.; Herndon, J. M.

1976-01-01

Results are reported for analysis of the uranium in multiple samples of each of six igneous-rock standards (dunite, granite, lujavrite, norite, pyroxenite, and syenite) prepared as geochemical reference standards for elemental and isotopic compositions. Powdered rock samples were examined by measuring delayed neutron emission after irradiation with a flux of the order of 10 to the 13th power neutrons/sq cm per sec in a nuclear reactor. The measurements are shown to compare quite favorably with previous uranium determinations for other standard rock samples.

The Mid-Cretaceous Frontier Formation near the Moxa Arch, southwestern Wyoming

USGS Publications Warehouse

Mereweather, E.A.; Blackmon, P.D.; Webb, J.C.

1984-01-01

The Frontier Formation in the Green River Basin of Wyoming, Utah, and Colorado, consists of sandstone, siltstone, and shale, and minor conglomerate, coal, and bentonite. These strata were deposited in several marine and nonmarine environments during early Late Cretaceous time. At north-trending outcrops along the eastern edge of the overthrust belt, the Frontier is of Cenomanian, Turonian, and early Coniacian age, and commonly is about 610 m (2,000 ft) thick. The formation in that area conformably overlies the Lower Cretaceous Aspen Shale and is divided into the following members, in ascending order: Chalk Creek, Coalville, Allen Hollow, Oyster Ridge Sandstone, and Dry Hollow. In west-trending outcrops on the northern flank of the Uinta Mountains in Utah, the Frontier is middle and late Turonian, and is about 60 m (200 ft) thick. These strata disconformably overlie the Lower Cretaceous Mowry Shale. In boreholes on the Moxa arch, the upper part of the Frontier is of middle Turonian to early Coniacian age and unconformably overlies the lower part of the formation, which is early Cenomanian at the south end and probably Cenomanian to early Turonian at the north end. The Frontier on the arch thickens northward from less than 100 m (328 ft) to more than 300 m (984 ft) and conformably overlies the Mowry. The marine and nonmarine Frontier near the Uinta Mountains, marine and mnmarine beds in the upper part of the formation on the Moxa arch and the largely nonmarine Dry Hollow Member at the top of the Frontier in the overthrust belt are similar in age. Older strata in the formation, which are represented by the disconformable basal contact of the Frontier near the Uinta Mountains, thicken northward along the Moxa arch and westward between the arch and the overthrust belt. The large changes in thickness of the Frontier in the Green River Basin were caused mainly by differential uplift and truncation of the lower part of the formation during the early to middle Turonian and by the shoreward addition of progressively younger sandstone units at the top of the formation during the late Turonian and early Coniacian. The sandstone in cores of the Frontier, from boreholes on the Moxa arch and the northern plunge of the Rock Springs uplift, consists of very fine grained and fine-grained litharenites and sublitharenites that were deposited in deltaic and shallow-water marine environments. These rocks consist mainly of quartz, chert, rock fragments, mixed-layer illite-smectite, mica-illite, and chlorite. Samples of the sandstone have porosities of 4.7 to 23.0 percent and permeabilities of 0.14 to 6.80 millidarcies, and seem to represent poor to fair reservoir beds for oil and gas. The shale in cores of the Frontier Formation and the overlying basal Hilliard Shale, from the Moxa arch, Rock Springs uplift, and overthrust belt, was deposited in deltaic and offshore-marine environments. Samples of the shale are composed largely of quartz, micaillite, mixed-layer illite-smectite, kaolin, and chlorite. They also contain from 0.27 to 4.42 percent organic carbon, in humic and sapropelic organic matter. Most of the sampled shale units are thermally mature, in terms of oil generation, and a few probably are source rocks for oil and gas.

Detecting Pore Fluid Pressure Changes by Using the Vp/Vs Ratio

NASA Astrophysics Data System (ADS)

Vanorio, T.; Mavko, G.

2006-12-01

A central problem in studies aimed at predicting the dynamic behavior of faults is monitoring and quantifying fluid changes in areas prone to overpressure. Experimental and modeling studies show the Vp/Vs ratio to be a good determinant of the saturation state of a rock formation as well as of its inner pore pressure condition. Dectecting pore pressure changes depends, among other causes, on the reliability of laboratory data to calibrate the in-situ measured velocities. Ideally, laboratory experiments performed under controlled conditions would identify the fundamental mechanisms responsible for changes in the measured acoustic properties. However, technical limitations in the laboratory together with the assumptions driving the experimental and modeling approaches rise spouriuos mechanisms which hinder our present understanding of the actual role of high pore pressure on the elastic and poroelastic parameters. Critical issues unclude: a) the frequencies used in the laboratory are responsible for high-frequency fluid effects which induce velocity dispersion. As a result, both the effective stress parameter and velocities (and their pressure-dependence) estimated from high- frequency ultrasonic data are different from those applicable to crustal low frequency wave propagation; b) laboratory measurements made at dry, drained conditions are assumed to mimic those in gas pressured rocks. However, in dry, drained conditions, no pore pressure is exerted in the pore space, and the pore gas is infinitely compressible; c) when using room-dry, drained measurements as the baseline to model pressured rock formations, the unloading path (i.e. decreasing confining pressure) is supposed to mimic the inflationary path due to pore pressure increase. Doing so, it is assumed that the amount of crack opening due to pore pressure is equal to that of crack closure caused by the overburden stress and thus, the effective stress coefficient is implicitely assumed equal to 1. To minimize the assumptions and limitations described above, we designed a laboratory experiment which used gas as pore fluid medium. Experimental results show that in gas-pressured saturated rocks the Vp/Vs ratio, while remaining lower than values reported for liquid saturation conditions, increases with decreasing differential pressure, similarly to the trend observed in liquid saturated rocks.

Sliding Rocks on Racetrack Playa, Death Valley National Park: First Observation of Rocks in Motion

PubMed Central

Lorenz, Ralph D.; Ray, Jib; Jackson, Brian

2014-01-01

The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved >60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, “windowpane” ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of ∼4–5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2–5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice. PMID:25162535

Phreatic and Hydrothermal Explosions: A Laboratory Approach

NASA Astrophysics Data System (ADS)

Scheu, B.; Dingwell, D. B.

2010-12-01

Phreatic eruptions are amongst the most common eruption types on earth. They might be precursory to another type of volcanic eruption but often they stand on their one. Despite being the most common eruption type, they also are one of the most diverse eruptions, in appearance as well as on eruption mechanism. Yet steam is the common fuel behind all phreatic eruptions. The steam-driven explosions occur when water beneath the ground or on the surface is heated by magma, lava, hot rocks, or fresh volcanic deposits (such as ignimbrites, tephra and pyroclastic-flow deposits) and result in crater, tuff rings and debris avalanches. The intense heat of such material may cause water to boil and flash to steam, thereby generating an explosion of steam, water, ash, blocks, and bombs. Another wide and important field affected by phreatic explosions are hydrothermal areas; here phreatic explosions occur every few months creating explosion craters and resemble a significant hazard to hydrothermal power plants. Despite of their hazard potential, phreatic explosions have so far been overlooked by the field of experimental volcanology. A part of their hazard potential in owned by the fact that phreatic explosions are hardly predictable in occurrence time and size as they have manifold triggers (variances in groundwater and heat systems, earthquakes, material fatigue, water level, etc..) A new set of experiments has been designed to focus on this phreatic type of steam explosion, whereas classical phreatomagmatic experiments use molten fuel-coolant interaction (e.g., Zimanowski, et al., 1991). The violent transition of the superheated water to vapour adds another degree of explosivity to the dry magmatic fragmentation, driven mostly by vesicle bursting due to internal gas overpressure. At low water fractions the fragmentation is strongly enforced by the mixture of these two effects and a large fraction of fine pyroclasts are produced, whereas at high water fraction in the sample the fragmentation is less violent as its dry counterpart. The experimental conditions used it this study (varying degree of water saturation, moderate overpressure, 200- 300°C) applies e.g. to volcanic rocks as well as country rocks at depth of about 100-800 m in a conduit or dome bearing a fraction of ground water and being heated from magma rising beneath (150-400°C). The diversity of phreatic eruptions at a volcanic system (vent) arises from the variety of host rocks, ways to seal the conduit, and to alter this material depending on the composition of volcanic gases. Here, we assess the influence of rapid decompression of the supercritical water phase in the pore space of samples, on the fragmentation behaviour. This will enable us to elucidate the characteristics of the different “fuels” for explosive fragmentation (gas overpressure, steam flashing), as well as their interplay.

U.S. Geological Survey silicate rock standards

USGS Publications Warehouse

Flanagan, F.J.

1967-01-01

The U.S. Geological Survey has processed six silicate rocks to provide new reference samples to supplement G-1 and W-1. Complete conventional, rapid rock, and spectrochemical analyses by the U.S. Geological Survey are reported for a granite (replacement for G-1), a granodiorite, an andesite, a peridotite, a dunite, and a basalt. Analyses of variance for nickel, chromium, copper, and zirconium in each rock sample showed that for these elements, the rocks can be considered homogeneous. Spectrochemical estimates are given for the nickel, chromium, copper, and zirconium contents of the samples. The petrography of five of the six rocks is described and CIPW norms are presented. ?? 1967.

6. 'ROCKFILLED CRIB 350 FEET LONG, REPAIRING DAMAGES CAUSED BY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. 'ROCK-FILLED CRIB 350 FEET LONG, REPAIRING DAMAGES CAUSED BY FLOODS DURING SEASON OF 1927 TO THE DRY GULCH CANAL HEADING.' 1928 - Irrigation Canals in the Uinta Basin, Duchesne, Duchesne County, UT

A method for development of a system of identification for Appalachian coal-bearing rocks

USGS Publications Warehouse

Ferm, J.C.; Weisenfluh, G.A.; Smith, G.C.

2002-01-01

The number of observable properties of sedimentary rocks is large and numerous classifications have been proposed for describing them. Some rock classifications, however, may be disadvantageous in situations such as logging rock core during coal exploration programs, where speed and simplicity are the essence. After experimenting with a number of formats for logging rock core in the Appalachian coal fields, a method of using color photographs accompanied by a rock name and numeric code was selected. In order to generate a representative collection of rocks to be photographed, sample methods were devised to produce a representative collection, and empirically based techniques were devised to identify repeatedly recognizable rock types. A number of cores representing the stratigraphic and geographic range of the region were sampled so that every megascopically recognizable variety was included in the collection; the frequency of samples of any variety reflects the frequency with which it would be encountered during logging. In order to generate repeatedly recognizable rock classes, the samples were sorted to display variation in grain size, mineral composition, color, and sedimentary structures. Class boundaries for each property were selected on the basis of existing, widely accepted limits and the precision with which these limits could be recognized. The process of sorting the core samples demonstrated relationships between rock properties and indicated that similar methods, applied to other groups of rocks, could yield more widely applicable field classifications. ?? 2002 Elsevier Science B.V. All rights reserved.

Frictional behaviour of sandstone: A sample-size dependent triaxial investigation

NASA Astrophysics Data System (ADS)

Roshan, Hamid; Masoumi, Hossein; Regenauer-Lieb, Klaus

2017-01-01

Frictional behaviour of rocks from the initial stage of loading to final shear displacement along the formed shear plane has been widely investigated in the past. However the effect of sample size on such frictional behaviour has not attracted much attention. This is mainly related to the limitations in rock testing facilities as well as the complex mechanisms involved in sample-size dependent frictional behaviour of rocks. In this study, a suite of advanced triaxial experiments was performed on Gosford sandstone samples at different sizes and confining pressures. The post-peak response of the rock along the formed shear plane has been captured for the analysis with particular interest in sample-size dependency. Several important phenomena have been observed from the results of this study: a) the rate of transition from brittleness to ductility in rock is sample-size dependent where the relatively smaller samples showed faster transition toward ductility at any confining pressure; b) the sample size influences the angle of formed shear band and c) the friction coefficient of the formed shear plane is sample-size dependent where the relatively smaller sample exhibits lower friction coefficient compared to larger samples. We interpret our results in terms of a thermodynamics approach in which the frictional properties for finite deformation are viewed as encompassing a multitude of ephemeral slipping surfaces prior to the formation of the through going fracture. The final fracture itself is seen as a result of the self-organisation of a sufficiently large ensemble of micro-slip surfaces and therefore consistent in terms of the theory of thermodynamics. This assumption vindicates the use of classical rock mechanics experiments to constrain failure of pressure sensitive rocks and the future imaging of these micro-slips opens an exciting path for research in rock failure mechanisms.

Experimental research on rock fracture failure characteristics under liquid nitrogen cooling conditions

NASA Astrophysics Data System (ADS)

Gao, Feng; Cai, Chengzheng; Yang, Yugui

2018-06-01

As liquid nitrogen is injected into a wellbore as fracturing fluid, it can rapidly absorb heat from warmer rock and generate cryogenic condition in downhole region. This will alter the physical conditions of reservoir rocks and further affect rock failure characteristics. To investigate rock fracture failure characteristics under liquid nitrogen cooling conditions, the fracture features of four types of sandstones and one type of marble were tested on original samples (the sample without any treatment) and cryogenic samples (the samples just taken out from the liquid nitrogen), respectively. The differences between original samples and cryogenic samples in load-displacement curves, fracture toughness, energy evolution and the crack density of ruptured samples were compared and analyzed. The results showed that at elastic deformation stage, cryogenic samples presented less plastic deformation and more obvious brittle failure characteristics than original ones. The average fracture toughness of cryogenic samples was 10.47%-158.33% greater than that of original ones, indicating that the mechanical strength of rocks used were enhanced under cooling conditions. When the samples ruptured, the cryogenic ones were required to absorb more energy and reserve more elastic energy. In general, the fracture degree of cryogenic samples was higher than that of original ones. As the samples were entirely fractured, the crack density of cryogenic samples was about 536.67% at most larger than that of original ones. This indicated that under liquid nitrogen cooling conditions, the stimulation reservoir volume is expected to be improved during fracturing. This work could provide a reference to the research on the mechanical properties and fracture failure of rock during liquid nitrogen fracturing.

Analyses and description of geochemical samples, Mill Creek Wilderness Study Area, Giles County, Virginia

USGS Publications Warehouse

Mei, Leung; Lesure, Frank Gardner

1978-01-01

Semiquantitative emission spectrographic analyses for 64 elements on 62 stream sediment and 71 rock samples from Mill Creek Wilderness Study area, Giles County, Virginia, are reported here in detail. Locations for all samples are given in Universal Transverse Mercator (UTM) coordinates. Brief descriptions of rock samples are also included. Rocks analysed are mostly sandstone. Samples of hematitic sandstone of the Rose Hill Formation and limonite-cemented sandstone of the Rocky Gap Sandstone contain high values of iron; these rocks are submarginal iron resources. Some of the same iron-rich samples have a little more barium, copper, cobalt, lead, silver, and/or zinc then is in average sandstone, but they do not suggest the presence of economic deposits of these metals. No other obviously anomalous values related to mineralized rock are present in the data.

Analyses and description of geochemical samples, Peters Mountain Wilderness Study Area, Giles County, Virginia

USGS Publications Warehouse

Rait, Norma; Lesure, Frank Gardner

1978-01-01

Semiquantitative emission spectrographic analyses for 64 elements on 43 stream sediment and 73 rock samples from Peters Mountain Wilderness Study area, Giles County, Virginia, are reported here in detail. Locations for all samples are in Universal Transverse Mercator (UTM) coordinates. Brie[ descriptions of rock samples are also included. Rocks analysed are mostly sandstone. Samples of hematitic sandstone of the Rose Hill Formation and limonite-cemented sandstone of the Rocky Gap Sandstone contain high values of iron; these rocks are submarginal iron resources. Some of the same iron-rich samples have a little more barium, copper, cobalt, lead, silver, and/or zinc then average sandstone, but they do not suggest the presence of economic deposits of these metals. No other obviously anomalous values related to mineralized rock are present in the data.

Trace Gases - A Warning Signs of Impending Major Seismic Activity

NASA Astrophysics Data System (ADS)

Baijnath, J.; Freund, F.; Li, J.

2013-12-01

Seismological models can predict future earthquakes only with wide uncertainty windows, typically on the order of decades to centuries. To improve short-term earthquake forecasts, it is essential to understand the non-seismic processes that take place in Earth's crust during the build-up of tectonic stresses. Days prior to the January 2001 M 7.6 Gujurat earthquake in India, there was a significant increase in the regional CO concentration, reaching 240 ppbv over a 100 squared kilometers, as derived from data of the MOPITT sensor onboard the NASA Terra satellite. A possible explanation for these observations is that when stresses in Earth's crust are building, positive hole charge carriers are activated, which are highly mobile and spread from deep below the earth to the surface. Positive holes act as highly oxidizing oxygen radicals, oxidizing water to hydrogen peroxide. It is hypothesized that, as positive hole charge carriers arrive from below and traverse the soil, they are expected to oxidize soil organics, converting aliphatics to ketones, formaldehyde, CO and CO2. This is tested by using a closed chamber with a slab of gabbro rock. Ultrasound generated by a pair of 50 W, 40 kHz piezoelectric transducers, applied to one end of the gabbro slab was used to activate the positive holes. This created a high concentration of positive holes at the end of the rock that the electrical conductivity through the rock increased more than 1000-fold, while the increase in conductivity through the other end of the gabbro slab was on the order of 100-fold. On the other end of the slab, rock dust and various soils were placed. A stainless steel mesh was also placed over the soil and dust to allow a current to flow through the granular material. When the far end of the slab was subjected to the ultrasound, currents as large as 250 nA were recorded flowing through the length of the gabbro slab and through the dust/soil pile. Dry dust/soil and dust samples impregnated with isopropanol and with a highly reduced butyn containing triple-bonded C and an aromatic ring were used. Multiple tests were conducted to study the interaction of stressed-activated positive hole charge carriers with organic versus inorganic and dry versus moist materials. This study suggests that the appearance of certain trace gases may be useful as a pre-earthquake indicator.

Digitally available interval-specific rock-sample data compiled from historical records, Nevada National Security Site and vicinity, Nye County, Nevada

USGS Publications Warehouse

Wood, David B.

2007-11-01

Between 1951 and 1992, 828 underground tests were conducted on the Nevada National Security Site, Nye County, Nevada. Prior to and following these nuclear tests, holes were drilled and mined to collect rock samples. These samples are organized and stored by depth of borehole or drift at the U.S. Geological Survey Core Library and Data Center at Mercury, Nevada, on the Nevada National Security Site. From these rock samples, rock properties were analyzed and interpreted and compiled into project files and in published reports that are maintained at the Core Library and at the U.S. Geological Survey office in Henderson, Nevada. These rock-sample data include lithologic descriptions, physical and mechanical properties, and fracture characteristics. Hydraulic properties also were compiled from holes completed in the water table. Rock samples are irreplaceable because pre-test, in-place conditions cannot be recreated and samples can not be recollected from the many holes destroyed by testing. Documenting these data in a published report will ensure availability for future investigators.

Improving the thermal and physical properties of fire clay refractory bricks by added magnesia

NASA Astrophysics Data System (ADS)

Ibrahim, Sarmad I.; Ali, Nahedh M.; Abood, Tamara W.

2018-05-01

In this study, the Local natural Iraqi rocks kaolin with the addition of different proportions of MgO along with its effects on the physical and thermal properties of the prepared refractories were investigated. kaolin/MgO mixture was milled and classified into various size fractions, the kaolin (less than 105 µm) and MgO (less than 50µm). The specimens were mixed from kaolin and MgO in range M1 (95+5)%, M2 (90+10) %, M3(85+15)% and M4(80+20)% respectively. The green specimens were shaped by the semi-dry method using a hydraulic press and a molding pressure of (5)Ton with addition of (9-12) %wt. of pva solution ratio. After molding and drying, the specimens were fired at (1100, 1200 and 1300)°C. Physical properties (density, porosity, Water Absorption) and thermal properties (thermal conductivity) were measured for all the prepared samples. The results showed that the porosity was increased and the density was decreased, such increase &decrease affected on to the thermal properties for refractory.

Relationship between anisotropies of permeability, electrical conductivity, and dielectric permittivity, with application to the Ellenburger dolomite reservoir analog

NASA Astrophysics Data System (ADS)

Kutemi, Titilope F.

The steady-state flow technique was employed to measure the flow rate of clean dry air through thirty core plugs (approximately 1" diameter) of the Ellenburger dolomite, drilled normal and parallel to the dominant fractures. Porosity was estimated by the method of imbibition. Electrical parameters (electrical conductivity and dielectric permittivity) were calculated from electrical resistance and capacitance measured as a function of frequency (100 Hz, 120 Hz, 1 KHz, and 10 KHz) and saturation (dry/ambient and brine saturated conditions). Another set of permeability data obtained by the method of pressure decay on similar samples was used for correlation. Anisotropies of permeability and electromagnetic parameters were established. Empirical relations between porosity (phi), permeability (k), electrical conductivity (sigma), and dielectric permittivity (epsilon) were defined via cross-plots and linear regressions. Prediction of k from sigma and epsilon was attempted; k from sigma was modeled from a combination of the Archie's relation and the Carman-Kozeny relation. Anisotropic EM responses are sensitive to saturation. Anisotropies of conductivity and permeability were observed to be controlled by the pore micro-structure. Although the rock is fractured, the fracture density appears insufficient to dominate the effects of primary structures in these samples of the Ellenburger dolomite. Model-based prediction of permeability from conductivity is generally unreliable, and is attributed to the underlying assumptions of the models, which are not consistent with the properties of the samples used for this study. Permeability was not predictable from dielectric permittivity.

Elastic Moduli and Seismic Wave Attenuation in Dry and Saturated Rock. Volume 2. Modulus Dispersion and Attenuation

DTIC Science & Technology

1992-07-31

aII 22 0 𔃺 4-4~ 00 0 c0 o +-+ 00 𔃺 + 0 ~ c ct~J $..- ~ct 0 00 (Rdo) snlnpou sUftnoA 23 00 X+ 0 +t XS cnI UCt r. V- -4- (00oo I) uoi𔃺IO 24x...and a QE of 688 was obtained at a resonant frequency of 15,531 Hz. The sample was then heated to 200’C at 10-8 Torr to further outgas it. It was cooled...Then QT began to increase from 150 0C to 4500C. Temperature QT - 100 1670 -50 1430 0 1330 50 800 100 620 150 700 250 900 350 950 450 900 Tittmann and

Alteration mineralogy and geochemistry as an exploration tool for detecting basement heat sources in sedimentary basins

NASA Astrophysics Data System (ADS)

Uysal, Tonguc; Gasparon, Massimo; van Zyl, Jacobus; Wyborn, Doone

2010-05-01

The Cooper Basin located in South Australia and Queensland hosts some of the hottest granites in the world at economic drilling depths (240°C at 3.5 km). Investigating the mechanism of heat-producing element enrichment in the Cooper Basin granite is crucial for understanding hot-dry rock geothermal systems and developing exploration strategies. Trace element (by ICP-MS) and stable isotope geochemistry of whole rock granite samples and hydrothermal phyllosilicate alteration minerals separated from the granite and overlying sandstones and mudstones of the Cooper Basin were examined in detail. Granite core samples from relatively shallow depths in Moomba 1 and Big Lake 1 are strongly altered with pervasive sericite (illite) and quartz precipitation, probably associated with intense micro-fracturing and veining. The intensity of hydrothermal alteration is less in deeper samples from Mcleod 1, Jolokia and Habanero 1. Highly altered granites from former holes are substantially enriched in lithophile elements, particularly in Cs, Rb, Be, Th, U and rare earth elements (REE) relative to the upper continental crust (UCC). U and Th contents with concentrations of up to 30 and 144 ppm, respectively, are 10 and 13 times higher than those of the UCC. Comparison of the trace element composition of the same samples dissolved by open beaker acid digestion and high-pressure acid bomb digestion (to dissolve zircon) shows that zircon is not the main repository of U and Th in the Cooper Basin granite. Instead, we propose that the enrichment of heat-producing elements was promoted by a regional hydrothermal event leading to the precipitation of U and Th- bearing minerals such as illite, K-feldspar and thorite. Crystallinity index (illite crystallinity) of the sericite indicates hydrothermal temperatures ranging from 250°C (in Moomba 1 and Big Lake 1) to 350°C (in McLeod 1 and Jolokia 1). In the overlying sedimentary rocks, crystallinity of authigenic illites translates to lower crystallisation temperatures (150-200°C). Normalised REE patterns of the mostly altered granite samples show a strong negative Ce anomaly, signifying oxidation of trivalent Ce to less soluble tetravalent Ce. Oxygen and hydrogen isotope compositions of illites from the granites and sedimentary rocks are very similar, with d18O = -1.8 per mill to +2.7 per mill; δD = -99 per mill to -121 per mill for granites and d18O = +2.3 per mill to +9.7 per mill, dD = -78 per mill to -119 per mill for sedimentary rocks. The calculated oxygen and hydrogen isotope compositions of fluids in equilibrium with the illites are depleted in 18O and deuterium, comparable to those of waters reported for most high-latitude sedimentary basins. Hence, stable isotope data of alteration minerals in the granite and the overlying sedimentary rocks suggest the operation of a hydrothermal system involving high latitude meteoric waters during extensional tectonism in the Cooper Basin region. Investigation of alteration mineralogy and geochemistry of relatively shallow sedimentary sections (generally intersected in previously drilled petroleum holes) represents a potentially strong tool to evaluate the presence of a geothermal heat source in the basement of sedimentary basins.

Mars Rover Mastcam View of Possible Mud Cracks

NASA Image and Video Library

2017-01-17

This view of a Martian rock slab called "Old Soaker," which has a network of cracks that may have originated in drying mud, comes from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover. The location is within an exposure of Murray formation mudstone on lower Mount Sharp inside Gale Crater. Mud cracks would be evidence of a time more than 3 billion years ago when dry intervals interrupted wetter periods that supported lakes in the area. Curiosity has found evidence of ancient lakes in older, lower-lying rock layers and also in younger mudstone that is above Old Soaker. Several images from Mastcam's left-eye camera are combined into this mosaic view. They were taken on Dec. 20, 2016, during the 1,555th Martian day, or sol, of Curiosity's work on Mars. The Old Soaker slab is about 4 feet (1.2 meters) long. Figure 1 includes a scale bar of 30 centimeters (12 inches). The scene is presented with a color adjustment that approximates white balancing, to resemble how the rocks and sand would appear under daytime lighting conditions on Earth. http://photojournal.jpl.nasa.gov/catalog/PIA21262

Using a hot dry rock geothermal reservoir for load following

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

Brown, D.W.; Duteau, R.J.

1995-01-01

Field measurements and modeling have shown the potential for using a Hot Dry Rock (HDR) geothermal reservoir for electric load following: either with Power-Peaking from a base-load operating condition, or for Pumped Storage of off-peak electric energy with a very significant thermal augmentation of the stored mechanical energy during periods of power production. For the base-load with power- peaking mode of operation, and HDR reservoir appears capable of producing over twice its nominal power output for short -- 2 to 4 hour -- periods of time. In this mode of operation, the reservoir normally would be produced under a high-backpressuremore » condition with the HDR reservoir region near the production well highly inflated. Upon demand, the production backpressure would be sharply reduced, surging the production flow. The analytical tool used in these investigations has been the transient finite element model of the an HDR reservoir called GEOCRACK, which is being developed by Professor Dan Swenson and his students at Kansas State University. This discrete-element representation of a jointed rock mass has recently been validated for transient operations using the set of cyclic reservoir operating data obtained at the end of the LTFT.« less

An experimental investigation of the effect of impact generated micro-deformations in Moenkopi and Coconino Sandstone from Meteor Crater, Arizona on subsequent weathering

NASA Astrophysics Data System (ADS)

Verma, A.; Bourke, M. C.; Osinski, G.; Viles, H. A.; Blanco, J. D. R.

2017-12-01

Impact cratering is an important geological process that affects all planetary bodies in our solar system. As rock breakdown plays an important role in the evolution of landforms and sediments, it is important to assess the role of inheritance in the subsequent breakdown of impacted rocks.The shock pressure of several gigapascals generated during the impact can exceed the effective strength of target lithology by three to four orders of magnitude and is responsible for melting, vaporisation, shock metamorphism, fracturing and fragmentation of rocks. Environmental conditions and heterogeneities in rock properties exert an important control in rock breakdown. Similar to other subaerial rocks, impacted rocks are affected by a range of rock breakdown processes. In order to better understand the role of inheritance of the impact on rock breakdown, a rock breakdown experiment was conducted in a simulated environmental cabinet under conditions similar to the arid conditions found at the Meteor Crater site. We sampled Moenkopi and Coconino Sandstone from the Meteor Crater impact site in Arizona. For comparison, samples were also collected at control sites close by that have similar rock formations but did not undergo impact. Several established techniques (X-ray CT, SEM, Equotip, SfM) were used to characterise the rock samples before the environmental cabinet experiments. Our laboratory analysis (XRD, SEM, optical microscopy, X-ray CT) on impacted rock samples from Meteor Crater, show that rock porosity and permeability changes due to compaction and fracturing during impact. There were no high-pressure polymorphs of quartz or glass detected in XRD analysis. We ran the experiments on a total of 28 petrophysically characterised 5x5x5 cm sample blocks of Coconino and Moenkopi Sandstone (24 impacted rocks and 4 non-impacted). The results will be presented at the AGU Fall meeting 2017.

Nuclear chemistry of returned lunar samples: Nuclide analysis by gamma-ray spectrometry

NASA Technical Reports Server (NTRS)

Kelley, G. D.; Eldridge, J. S.

1972-01-01

Concentrations of primordial radioelements and of cosmogenic radionuclides in crystalline rocks, breccias, and soils from the Ocean of Storms were determined. Concentrations of K, Th, U, Al-26, and Na-22 were determined for seven clastic or brecciated rocks, three sieved samples of fines, and one composite sample of sawdust from the cutting of a fragmental rock, all from samples obtained on the Apollo 14 mission. The K, Th, and U concentrations and cogmogenic radionuclide abundances in rocks and soils from Apollo 15 are also discussed.

Evaluation of seasonal variation of water quality using multivariate statistical analysis and irrigation parameter indices in Ajakanga area, Ibadan, Nigeria

NASA Astrophysics Data System (ADS)

Ganiyu, S. A.; Badmus, B. S.; Olurin, O. T.; Ojekunle, Z. O.

2018-03-01

The variation of groundwater quality across different regions is of great importance in the study of groundwater so as to ascertain the sources of contaminants to available water sources. Geochemical assessment of groundwater samples from hand-dug wells were done within the vicinity of Ajakanga dumpsite, Ibadan, Southwestern, Nigeria, with the aim of assessing their suitability for domestic and irrigation purposes. Ten groundwater samples were collected both in dry and wet seasons for analysis of physicochemical parameters such as: pH, EC, TDS, Na+, K+, Ca2+, Mg2+, HCO3^{ - } Cl-, SO4^{2 - }, NO3^{2 - } principal component analysis (PCA) and cluster analysis (CA) were used to determine probable sources of groundwater contamination. The results of the analyses showed the groundwater samples to be within permissible limits of WHO/NSDWQ, while elevated values of concentrations of most analyzed chemical constituents in water samples were noticed in S1 and S10 due to their nearness to the dumpsite and agricultural overflow, respectively. Groundwater in the study area is of hard, fresh and alkaline nature. There are very strong associations between EC and TDS, HCO3^{ - } and CO3^{2 - } in both seasons. PCA identified five and three major factors accounting for 95.7 and 88.7% of total variation in water quality for dry and wet seasons, respectively. PCA also identified factors influencing water quality as those probably related to mineral dissolution, groundwater-rock interaction, weathering process and anthropogenic activities from the dumpsite. Results of CA show groups based on similar water quality characteristics and on the extent of proximity to the dumpsite. Assessment for irrigation purpose showed that most of the water samples were suitable for agricultural purpose except in a few locations.

The mechanics of stick-slip

USGS Publications Warehouse

Byerlee, J.D.

1970-01-01

Physical mechanisms that have been proposed to explain the occurrence of stick-slip motion during frictional sliding have been examined in the light of results obtained from experiments with rocks and brittle minerals. An instability caused by sudden brittle fracture of locked regions on surfaces in contact is the most likely explanation for stick-slip during dry frictional sliding of brittle rocks at room temperature. Areas requiring further study and the uncertainties in applying the results of laboratory experiments to earthquake studies are emphasized. ?? 1970.

Hot dry rock geothermal energy development program. Semiannual report, October 1, 1978-March 31, 1979

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

Brown, M.C.; Nunz, G.J.; Cremer, G.M.

1979-09-01

The potential of energy extracted from hot dry rock (HDR) was investigated as a commercailly feasible alternate energy source. Run Segments 3 and 4 were completed in the prototype reservoir of the Phase I energy-extraction system at Fenton Hill, New Mexico. Results of these tests yielded significant data on the existing system and this information will be applicable to future HDR systems. Plans and operations initiating a Phase II system are underway at the Fenton Hill site. This system, a deeper, hotter commercial-size reservoir, is intended to demonstrate the longevity and economics of an HDR system. Major activity occurred inmore » evaluation of the national resource potential and in characterizing possible future HDR geothermal sites. Work has begun in the institutional and industrial support area to assess the economics and promote commercial interest in HDR systems as an alternate energy source.« less

Vanadium in landscape components of western Transbaikalia

NASA Astrophysics Data System (ADS)

Kashin, V. K.

2017-10-01

Vanadium in soil-forming rocks, soils, and vegetation of forest-steppe, steppe, and dry-steppe landscapes of Transbaikalia has been studied. The mean element contents in rocks and soils are equal to its mean natural abundances (clarke values). The content of vanadium in soils is strictly determined by its content in parent materials; its dependence on the vanadium concentration in plants and on the soil pH and humus is less pronounced. With respect to the coefficient of biological uptake by plants, vanadium is assigned to the group of elements of slight accumulation (0.10-0.33) on mineral soils and of moderate accumulation (1.1-1.5) on peat bog soils. The mean vanadium concentration in steppe, meadow, and cultivated vegetation exceeds the norm for animals by 1.7-2.6 times but does not rich toxic levels. Vanadium uptake by plants is most intensive in meadow cenoses and is less intensive in dry-steppe cenoses.

Occurrence Prospect of HDR and Target Site Selection Study in Southeastern of China

NASA Astrophysics Data System (ADS)

Lin, W.; Gan, H.

2017-12-01

Hot dry rock (HDR) geothermal resource is one of the most important clean energy in future. Site selection a HDR resource is a fundamental work to explore the HDR resources. This paper compiled all the HDR development projects domestic and abroad, and summarized the location of HDR geothermal geological index. After comparing the geological background of HDR in the southeast coastal area of China, Yangjiang Xinzhou in Guangdong province, Leizhou Peninsula area, Lingshui in Hainan province and Huangshadong in Guangzhou were selected from some key potential target area along the southeast coast of China. Deep geothermal field model of the study area is established based on the comprehensive analysis of the target area of deep geothermal geological background and deep thermal anomalies. This paper also compared the hot dry rock resources target locations, and proposed suggestions for the priority exploration target area and exploration scheme.

The Polar Rock Repository: Rescuing Polar Collections for New Research

NASA Astrophysics Data System (ADS)

Grunow, A.

2016-12-01

Geological field expeditions in polar regions are logistically difficult, financially expensive and can have a significant environmental impact on pristine regions. The scarcity of outcrop in Antarctica (98% ice-covered) makes previously collected rock samples very valuable to the science community. NSF recognized the need for preserving rock, dredge, and terrestrial core samples from polar areas and created the Polar Rock Repository (PRR). The PRR collection allows for full and open access to both samples and metadata via the PRR website. In addition to the physical samples and their basic metadata, the PRR archives supporting materials from the collector, field notebooks, images of the samples, field maps, air photos, thin sections and any associated bibliography/DOI's. Many of these supporting materials are unique. More than 40,000 samples are available from the PRR for scientific analysis to researchers around the globe. Most of the samples cataloged at the PRR were collected more than 30 years ago, some more than 100 years ago. The rock samples and metadata are made available online through an advanced search engine for the PRR website. This allows scientists to "drill down" into search results using categories and look-up object fields similar to websites like Amazon. Results can be viewed in a table, downloaded as a spreadsheet, or plotted on an interactive map that supports display of satellite imagery and bathymetry layers. Samples can be requested by placing them in the `shopping cart'. These old sample collections have been repeatedly used by scientists from around the world. One data request involved locating coal deposits in Antarctica for a global compilation and another for looking at the redox state of batholithic rocks from the Antarctic Peninsula using magnetic susceptibilities of PRR rocks. Sample usage has also included non-traditional geologic studies, such as a search for monopoles in Cenozoic volcanic samples, and remote sensing/spectral imaging of Transantarctic Mountains rocks. Rescuing these collections from universities that no longer want to store the rocks or from researchers who no longer need the samples has resulted in many new publications, new proposals and enormous cost and environmental savings to the U.S. Antarctic science program.

Comparison of drying characteristic and uniformity of banana cubes dried by pulse-spouted microwave vacuum drying, freeze drying and microwave freeze drying.

PubMed

Jiang, Hao; Zhang, Min; Mujumdar, Arun S; Lim, Rui-Xin

2014-07-01

To overcome the flaws of high energy consumption of freeze drying (FD) and the non-uniform drying of microwave freeze drying (MFD), pulse-spouted microwave vacuum drying (PSMVD) was developed. The results showed that the drying time can be dramatically shortened if microwave was used as the heating source. In this experiment, both MFD and PSMVD could shorten drying time by 50% as compared to the FD process. Depending on the heating method, MFD and PSMVD dried banana cubes showed trends of expansion while FD dried samples demonstrated trends of shrinkage. Shrinkage also brought intensive structure and highest fracturability of all three samples dried by different methods. The residual ascorbic acid content of PSMVD dried samples can be as high as in FD dried samples, which were superior to MFD dried samples. The tests confirmed that PSMVD could bring about better drying uniformity than MFD. Besides, compared with traditional MFD, PSMVD can provide better extrinsic feature, and can bring about improved nutritional features because of the higher residual ascorbic acid content. © 2013 Society of Chemical Industry.

Growth rate of a penny-shaped crack in hydraulic fracturing of rocks

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

Abe, H.; Mura, T.; Keer, L.M.

1976-10-10

The stable growth of a crack created by the hydraulic pressurizing of a penny-shaped crack in a dry rock mass is investigated. The rock mass is infinitely extended, homogeneous, and isotropic. It is verified on the basis of the equations of fluid dynamics that the fracturing fluid cannot penetrate the entire domain of a crack when the crack is moving. The effects of various terms in the basic equations also are studied. The solution of some typical examples is given, and the significant effect of the stress intensity factor of the rock on the crack propagation is shown. When themore » crack is expanding under a constant flow rate, the classical solution by Sack is found to be approx. valid for very large cracks, and nevertheless the crack is stable. (11 refs.)« less

Growth rate of a penny-shaped crack in hydraulic fracturing of rocks

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

Abe, H.; Mura, T.; Keer, L.M.

1976-10-10

The stable growth of a crack created by the hydraulic pressurizing of a penny-shaped crack in a dry rock mass is investigated. The rock mass is infinitely extended, homogeneous, and isotropic. It is verified on the basis of the equations of fluid dynamics that the fracturing fluid cannot penetrate the entire domain of a crack when the crack is moving. The effects of various terms in the basic equations are also studied. The solution of some typical examples is given, and the significant effect of the stress intensity factor of the rock on the crack propagation is shown. When themore » crack is expanding under a constant flow rate, the classical solution by Sack is found to be approximately valid for very large cracks, and nevertheless the crack is stable.« less

Location-Related Differences in Weathering Behaviors and Populations of Culturable Rock-Weathering Bacteria Along a Hillside of a Rock Mountain.

PubMed

Wang, Qi; Wang, Rongrong; He, Linyan; Sheng, Xiafang

2017-05-01

Bacteria play important roles in rock weathering, elemental cycling, and soil formation. However, little is known about the weathering potential and population of bacteria inhabiting surfaces of rocks. In this study, we isolated bacteria from the top, middle, and bottom rock samples along a hillside of a rock (trachyte) mountain as well as adjacent soils and characterized rock-weathering behaviors and populations of the bacteria. Per gram of rock or surface soil, 10 6 -10 7 colony forming units were obtained and total 192 bacteria were isolated. Laboratory rock dissolution experiments indicated that the proportions of the highly effective Fe (ranging from 67 to 92 %), Al (ranging from 40 to 48 %), and Cu (ranging from 54 to 81 %) solubilizers were significantly higher in the top rock and soil samples, while the proportion of the highly effective Si (56 %) solubilizers was significantly higher in the middle rock samples. Furthermore, 78, 96, and 6 % of bacteria from the top rocks, soils, and middle rocks, respectively, significantly acidified the culture medium (pH < 4.0) in the rock dissolution process. Most rock-weathering bacteria (79 %) from the rocks were different to those from the soils and most of them (species level) have not been previously reported. Furthermore, location-specific rock-weathering bacterial populations were found and Bacillus species were the most (66 %) frequently isolated rock-weathering bacteria in the rocks based on cultivation methods. Notably, the top rocks and soils had the highest and lowest diversity of rock-weathering bacterial populations, respectively. The results suggested location-related differences in element (Si, Al, Fe, and Cu) releasing effectiveness and communities of rock-weathering bacteria along the hillside of the rock mountain.

[Spectral characteristics and implications of quartz from Heliao lead-zinc polymetallic ore district in the south of Qinzhou-Hangzhou joint belt].

PubMed

Lü, Wen-Chao; Yang, Zhi-Jun; Zhou, Yong-Zhang; Li, Hong-Zhong; Zeng, Xiang-Qing; Chen, Qing; Liang, Jin; Zeng, Chang-Yu

2013-05-01

The XRD, FTIR and Raman spectrum were employed to study the characters of quartz from three types of rock samples, which are mineralized rock sample, near ore body rock sample and far away from ore body rock sample in Heliao lead-zinc polymetallic ore district. The research shows that the quartz in the mineralized rock and far away from ore body rock is pure, while the quartz in near ore body rock contains a small amount of impurities. But such small amounts of impurities did not cause apparent change in the quartz lattice parameters. From far away from ore body rock-->near ore body rock-->mineralized rock, the crystallinity and order degree of quartz are higher and higher. And the quartz in the mineralized rock has a trend to change into low symmetry quartz. It's a unique to mineralized rock that the quartz's absorption peak at 1 050 cm(-1) was split into two strongest ones. It can be used as the signs of whether exists mineralization. The cause for the quartz microstructure changes may be related to the activities of late mineralized hydrothermal fluids. Late hydrothermal influence was very weak to the quartz far away from ore body rock. And through the impact of the multi-stage hydrothermal effect, the quartz in mineralized rock may be purified by recrystallization and structural adjustment. However the quartz in near ore body rock didn't have enough hydrothermal influence, so it's not pure. Genealogy research technology is a useful technique for in-depth exploration of study area mineralization process and metallogenic regularity.

Effect of Particle Shape on Mechanical Behaviors of Rocks: A Numerical Study Using Clumped Particle Model

PubMed Central

Rong, Guan; Liu, Guang; Zhou, Chuang-bing

2013-01-01

Since rocks are aggregates of mineral particles, the effect of mineral microstructure on macroscopic mechanical behaviors of rocks is inneglectable. Rock samples of four different particle shapes are established in this study based on clumped particle model, and a sphericity index is used to quantify particle shape. Model parameters for simulation in PFC are obtained by triaxial compression test of quartz sandstone, and simulation of triaxial compression test is then conducted on four rock samples with different particle shapes. It is seen from the results that stress thresholds of rock samples such as crack initiation stress, crack damage stress, and peak stress decrease with the increasing of the sphericity index. The increase of sphericity leads to a drop of elastic modulus and a rise in Poisson ratio, while the decreasing sphericity usually results in the increase of cohesion and internal friction angle. Based on volume change of rock samples during simulation of triaxial compression test, variation of dilation angle with plastic strain is also studied. PMID:23997677

Effect of particle shape on mechanical behaviors of rocks: a numerical study using clumped particle model.

PubMed

Rong, Guan; Liu, Guang; Hou, Di; Zhou, Chuang-Bing

2013-01-01

Since rocks are aggregates of mineral particles, the effect of mineral microstructure on macroscopic mechanical behaviors of rocks is inneglectable. Rock samples of four different particle shapes are established in this study based on clumped particle model, and a sphericity index is used to quantify particle shape. Model parameters for simulation in PFC are obtained by triaxial compression test of quartz sandstone, and simulation of triaxial compression test is then conducted on four rock samples with different particle shapes. It is seen from the results that stress thresholds of rock samples such as crack initiation stress, crack damage stress, and peak stress decrease with the increasing of the sphericity index. The increase of sphericity leads to a drop of elastic modulus and a rise in Poisson ratio, while the decreasing sphericity usually results in the increase of cohesion and internal friction angle. Based on volume change of rock samples during simulation of triaxial compression test, variation of dilation angle with plastic strain is also studied.

Experimental results of temperature response to stress change: An indication of the physics of earthquake rupture propagation

NASA Astrophysics Data System (ADS)

Lin, W.; Yang, X.; Tadai, O.; Zeng, X.; Yeh, E. C.; Yu, C.; Hatakeda, K.; Xu, H.; Xu, Z.

2016-12-01

As a result of the earthquake rupture propagation, stress on the earthquake fault and in the hanging wall and in the footwall coseismically drops. Based on the thermo-elasticity theory, the temperature of rocks may change associated with coseismic stress change at the same time as their elastic deformation. This coseismic temperature change is one of the physics of earthquake rupture propagation, however has not been noted and expressly addressed before. To understand this temperature issue, we conducted laboratory experiments to quantitatively investigate temperatures response of rocks to rapid stress change of various typical rocks. Consequently, we developed a hydrostatic compression experimental equipment for rock samples with a high resolution temperature measuring system. This enable us to rapidly load and/or unload the confining pressure. As experimental rock samples, we collected 15 representative rocks from various scientific drilling projects and outcrops of earthquake faults, and quarries in the world. The rock types include sandstone, siltstone, limestone, granite, basalt, tuff etc. Based on the classical thermo-elastic theory, a conventional relationship between the temperature change (dT) of rock samples and the confining pressure change (dP) in the hydrostatic compression system under adiabatic condition can be expressed as a linear function. Therefore, we can measure the adiabatic pressure derivative of temperature (dT/dP) directly by monitoring changes of rock sample temperature and confining pressure during the rapidly loading and unloading processes. As preliminary results of the experiments, the data of 15 rock samples showed that i) the adiabatic pressure derivative of temperature (dT/dP) of most rocks are about 1.5 6.2 mK/MPa; ii) the dT/dP of sedimentary rocks is larger than igneous and metamorphic rocks; iii) a good linear correlation between dT/dP and the rock's bulk modulus was recognized.

Cooperative investigation of precision and accuracy: In chemical analysis of silicate rocks

USGS Publications Warehouse

Schlecht, W.G.

1951-01-01

This is the preliminary report of the first extensive program ever organized to study the analysis of igneous rocks, a study sponsored by the United States Geological Survey, the Massachusetts Institute of Technology, and the Geophysical Laboratory of the Carnegie Institution of Washington. Large samples of two typical igneous rocks, a granite and a diabase, were carefully prepared and divided. Small samples (about 70 grams) of each were sent to 25 rock-analysis laboratories throughout the world; analyses of one or both samples were reported by 34 analysts in these laboratories. The results, which showed rather large discrepancies, are presented in histograms. The great discordance in results reflects the present unsatisfactory state of rock analysis. It is hoped that the ultimate establishment of standard samples and procedures will contribute to the improvement of quality of analyses. The two rock samples have also been thoroughly studied spectrographically and petrographically. Detailed reports of all the studies will be published.

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

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

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

1994-08-01

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

Seismic velocities in fractured rocks: An experimental verification of Hudson`s theory

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

Peacock, S.; McCann, C.; Sothcott, J.

1994-01-01

Flow of fluids in many hydrocarbon reservoirs aquifers is enhanced by the presence of cracks and fractures. These cracks could be detected by their effects on propagation of compressional and shear waves through the reservoir: several theories, including Hudson`s, claim to predict the seismic effects of cracks. Although Hudson`s theory has already been used to calculate crack densities from seismic survey`s, the predictions of the theory have not yet been tested experimentally on rocks containing a known crack distribution. This paper describes an experimental verification of the theory. The rock used, Carrara marble, was chosen for its uniformity and lowmore » porosity, so that the effect of cracks would not be obscured by other influences. Cracks were induced by loading of laboratory specimens. Velocities of compressional and shear waves were measured by ultrasound at 0.85 MHz in dry and water-saturated specimens at high and low effective pressures.The cracks were then counted in polished sections of the specimens. In ``dry`` specimens with both dry and saturated cracks, Hudson`s theory overpredicted observed crack densities by a constant amount that is attributed to the observed value being systematically underestimated. The theory made poor predictions for fully saturated specimens. Shear-wave splitting, caused by anisotropy due to both crystal and crack alignment, was observed. Cracks were seen to follow grain boundaries rather than the direction of maximum compression due to loading. The results demonstrate that Hudson`s theory may be used in some cases to determine crack and fracture densities from compressional- and shear-wave velocity data.« less

Echo Source Discrimination in Airborne Radar Sounding Data for Mars Analog Studies, Dry Valleys, Antarctica

NASA Technical Reports Server (NTRS)

Holt, J. W.; Blankenship, D. D.; Peters, M. E.; Kempf, S. D.; Morse, D. L.; Williams, B. J.

2003-01-01

The recent identification of features on Mars exhibiting morphologies consistent with ice/rock mixtures, near-surface ice bodies and near-surface liquid water [1,2], and the importance of such features to the search for water on Mars, highlights the need for appropriate terrestrial analogs in order to prepare for upcoming radar missions targeting these and other water-related features. Climatic, hydrological, and geological conditions in the McMurdo Dry Valleys of Antarctica are analogous in many ways to those on Mars, and a number of ice-related features in the Dry Valleys may have direct morphologic and compositional counterparts on Mars.

Vertical Profiles Of 226Ra, 232Th And 40K Activities In Rocks From The Irati Formation Of The Paraná Sedimentary Basin, Southern Brazil

NASA Astrophysics Data System (ADS)

Ferreira, Ademar de O.; Bastos, Rodrigo O.; Appoloni, Carlos R.

2008-08-01

Naturally occurring radioisotopes are present in different concentrations in sedimentary rocks, reflecting the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. Using a high-resolution γ-ray spectrometry methodology, sedimentary rocks were measured to assess the concentration activities of the natural radioisotopes. The surveyed rocks are from the Irati formation in the Paraná sedimentary basin, which are exposed by an abandoned, open-pit limestone mine, in the city of Sapopema, southern Brazil. The exposed vertical profile is 5 m, and its stratigraphy is represented by an alternation of limestone and bituminous shale (layers being a few decimeters thick), and some millimeter rhythm layers with limestone and bituminous shale laminas. Eleven samples were collected along this profile, each of them dried in the open air during 48 hours, sieved through 4 mm mesh and sealed in cylindrical recipients. Measurements were accomplished using a 66% relative efficiency HPGE detector connected to a standard gamma ray spectrometry electronic chain. The detector efficiency in the range of 60 to 1800 keV was carried out with the certified IAEA-385 sediment sample. The Lower Limit of Detection (LLD) to the system is 2.40 Bqṡkg-1 for 226Ra, 1.84 Bqṡkg-1 for 232Th and 4.20 Bqṡkg-1 for 40K. Activity concentrations were determined for 226Ra (from 16.22 to 151.55 Bqṡkg-1), 232Th (from 2.93 to 56.12 Bqṡkg-1) and 40K (from 38.45 to 644.63 Bqṡkg-1). The layers enriched with organic matter presented the higher values of activity. The measured concentrations of the natural radioisotopes were lower for limestone samples (average values and respective deviations were 22.81±0.22 Bqṡkg-1 for 226Ra, 4.21±0.07 Bqṡkg-1 for 232Th, and 50.11±0.82 Bqṡkg-1 for 40K). Higher concentrations were measured for the bituminous shale samples (average values and respective deviations were 108.10±12.17 Bqṡkg-1 for 226Ra, 43.69±0.30 Bqṡkg-1 for 232Th, and 465.82±3.99 Bqṡkg-1 for 40K). The concentrations were intermediate for the rhythmite samples (average values and respective deviations were 50.69±1.09 Bqṡkg-1 for 226Ra, 7.63±0.21 Bqṡkg-1 for 232Th, and 85.96±2.47 Bqṡkg-1 for 40K). As the analyzed rocks are raw materials for the ceramic, cement and soil correction compound industries, the results of this work furnish data to estimate the contribution of these products to the general public's radiation exposure.

Long-term effects of CO2 on the mechanical behaviour of faults - a study of samples from a natural CO2 analogue (Entrada Sandstone, Utah, USA)

NASA Astrophysics Data System (ADS)

Bakker, E.; Hangx, S.; Spiers, C. J.

2012-12-01

CO2 capture followed by storage in depleted oil and gas reservoirs is currently seen as one of the most promising CO2-mitigation strategies. An important issue in relation to long-term CO2 storage is the prediction of the effects of fluid-rock interaction on the mechanical integrity and sealing capacity of the reservoir-seal system, on timescales of the order of 103 or 104 years. However, the assumed chemical interactions in the rock/CO2/brine system are slow, so that their long-term effects on rock composition, microstructure, mechanical properties and transport properties cannot be reproduced in laboratory experiments. One way to address this is to study the effects of reactions in natural CO2 reservoirs, using a so-called natural analogue approach. We tackled the question of how reactions characterizing natural CO2 fields affect fault friction, fault reactivation potential and seismic vs. aseismic slip stability, as well as transmissivity evolution during and after fault reactivation. Simulated fault gouges were prepared by crushing material obtained from surface outcrops of the Entrada Sandstone, a locally CO2-bearing formation forming an analogue field under the Colorado Plateau, Utah, USA . We used three types of starting material: 1) CO2 unaffected (unbleached) samples consisting mainly of quartz and feldspar, 2) "bleached" samples, and 3) heavily cemented/altered fault rock containing a high percentage of carbonates (> 40 wt%). The latter two were altered as a result of interaction with CO2-rich fluids over geological time. We performed triaxial direct shear experiments on these materials at room temperature under nominally dry conditions, at normal stresses up to 90 MPa and shear velocities of 0.22 -10.9 μm/s. The results of the experiments yielded friction coefficients (μ= τ/σn) of 0.55-0.85 for unbleached sandstone gouge and 0.45-0.80 for bleached material, while the fault material showed systematically higher friction coefficients (0.60-0.95). All simulated gouges showed a decrease in friction coefficient of 20-30% with increasing normal stress up to 90 MPa, with almost all samples showing velocity-strengthening (stable) slip behaviour. Permeability measurements show only minor changes during shear. Overall, our results demonstrated that higher (CO2-related) carbonate content leads to higher frictional strength and increased velocity strengthening (slip stability), notably at low normal stresses. However, preliminary results recently obtained at elevated temperatures show that carbonate-rich samples show velocity-weakening behaviour at 100°C, which is in line with previous studies on pure carbonates. A natural analogue from The Netherlands shows similar results for the chemical alteration of reservoir rock by the presence of naturally long-term stored CO2.

Cosmogenic nuclides in football-sized rocks.

NASA Technical Reports Server (NTRS)

Wahlen, M.; Honda, M.; Imamura, M.; Fruchter, J. S.; Finkel, R. C.; Kohl, C. P.; Arnold, J. R.; Reedy, R. C.

1972-01-01

The activity of long- and short-lived isotopes in a series of samples from a vertical column through the center of rock 14321 was measured. Rock 14321 is a 9 kg fragmental rock whose orientation was photographically documented on the lunar surface. Also investigated was a sample from the lower portion of rock 14310, where, in order to study target effects, two different density fractions (mineral separates) were analyzed. A few nuclides in a sample from the comprehensive fines 14259 were measured. This material has been collected largely from the top centimeter of the lunar soil. The study of the deep samples of 14321 and 14310 provided values for the activity of isotopes at points where only effects produced by galactic cosmic rays are significant.

Rock sample brought to earth from the Apollo 12 lunar landing mission

NASA Image and Video Library

1969-12-04

S69-60909 (November 1969) --- A close-up view of lunar sample 12,052 under observation in the Manned Spacecraft Center's Lunar Receiving Laboratory (LRL). Astronauts Charles Conrad Jr., and Alan L. Bean collected several rocks and samples of finer lunar matter during their Apollo 12 lunar landing mission extravehicular activity (EVA). This particular sample was picked up during the second space walk (EVA) on Nov. 20, 1969. It is a typically fine-grained crystalline rock with a concentration of holes on the left part of the exposed side. These holes are called vesicles and have been identified as gas bubbles formed during the crystallization of the rock. Several glass-lined pits can be seen on the surface of the rock.

Rockballer Sample Acquisition Tool

NASA Technical Reports Server (NTRS)

Giersch, Louis R.; Cook, Brant T.

2013-01-01

It would be desirable to acquire rock and/or ice samples that extend below the surface of the parent rock or ice in extraterrestrial environments such as the Moon, Mars, comets, and asteroids. Such samples would allow measurements to be made further back into the geologic history of the rock, providing critical insight into the history of the local environment and the solar system. Such samples could also be necessary for sample return mission architectures that would acquire samples from extraterrestrial environments for return to Earth for more detailed scientific investigation.

Analyses and descriptions of geochemical samples, Mountain Lake Wilderness Study Area, Virginia and West Virginia

USGS Publications Warehouse

Mei, Leung; Fletcher, J.D.; Rait, Norma; Lesure, F.G.

1978-01-01

Semiquantitative emission spectrographic analyses for 64 elements on 95 stream sediment and 122 rock samples from Mountain Lake Wilderness Study Area, Giles and Craig Counties, Virginia and Monroe County, West Virginia, are reported here in detail. Locations for all samples are in Universal Transverse Mercator (UTM) coordinates. Brief descriptions of rock samples are also included. Rocks analysed are mostly sandstone. Samples of hematitic sandstone of the Rose Hill Formation and limonite-cemented sandstone of the Rocky Gap Sandstone contain high values of iron; these rocks are submarginal iron resources. Some of these iron-rich samples have a little more barium, copper, cobalt, lead, silver, and/or zinc than in average sandstone, but they do not suggest the presence of economic deposits of these metals. A few samples of Tuscarora Quartzite contain moderate amounts of manganese. These are from a submarginal manganese resource. No other obviously anomalous-values related to mineralized rock are present in the data.

Mineralogy and Geochemistry of Granitic rocks within Lichen Hills, Outback Nunatak, Northern Victoria Land, Antarctica

NASA Astrophysics Data System (ADS)

KIM, T.; KIM, Y.; Lee, I.; Lee, J.; Woo, J.

2015-12-01

The study areas, Lichen Hills and Outback Nunatak are located in the Northern Victoria Land which is close to Pacific Ocean side of Transantarctic Mountain (TAM), Antarctica. According to the study of Zeller and Dreschoff (1990), the radioactivity values of Lichen hills and Frontier Mt. area in the Victoria Land were very high. To identify the geochemical characteristics of granitic rocks in these areas, 13 samples of Lichen Hills rocks and 4 samples of Outback Nunatak rocks are analyzed. For mineralogical study, samples were observed in macroscale as well as microscale including microscope electron probe analysis. Rock samples of Lichen Hills, Outback Nunatak are mainly leucogranite and granitic pegmatite. These rock samples are composed of quartz, k-feldspar, plagioclase, muscovite, garnet, tourmaline like granite. In SEM-EDS analysis, the observed light colored minerals show relatively high Th, U, Dy, Ce, Nb concentration. This suggests that rock samples may contain minerals such as fergusonite, monazite, thorite, allanite, karnasurtite which are considered to be REE-bearing minerals. Samples of related rocks have been analyzed in terms of major, trace and rare earth element (REE) concentrations using X-ray fluorescence (XRF) spectrometer and Inductively Coupled Plasma Mass Spectrometer (ICP-MS). As concentration of SiO2 increase, Al2O3, TiO2, Fe2O3, MgO, P2O5 concentration decrease and Na2O, K2O, MnO concentration increase. Analyzed trace elements and REE are normalized using CI Chondrite, Primitive mantle. The normalized data show that LREE are enriched compared to HREE. The distinct negative anomalies of Eu, Sr are observed, indicating that rock-forming melts are fairly processed state of fractional crystallization. It means that Th, U, Nb, Ta are much enriched in the melts.

40 CFR 98.264 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... requirements. (a) You must obtain a monthly grab sample of phosphate rock directly from the rock being fed to... Methods Used and Adopted by the Association of Fertilizer and Phosphate Chemists (AFPC). If phosphate rock is obtained from more than one origin in a month, you must obtain a sample from each origin of rock...

40 CFR 98.264 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... requirements. (a) You must obtain a monthly grab sample of phosphate rock directly from the rock being fed to..., Bartow, Florida 33831, (863) 534-9755, http://afpc.net, [email protected]). If phosphate rock is obtained from more than one origin in a month, you must obtain a sample from each origin of rock or obtain...

40 CFR 98.264 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... requirements. (a) You must obtain a monthly grab sample of phosphate rock directly from the rock being fed to..., Bartow, Florida 33831, (863) 534-9755, http://afpc.net, [email protected]). If phosphate rock is obtained from more than one origin in a month, you must obtain a sample from each origin of rock or obtain...

40 CFR 98.264 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... requirements. (a) You must obtain a monthly grab sample of phosphate rock directly from the rock being fed to..., Bartow, Florida 33831, (863) 534-9755, http://afpc.net, [email protected]). If phosphate rock is obtained from more than one origin in a month, you must obtain a sample from each origin of rock or obtain...

LUNAR SAMPLES - APOLLO 11 - MSC

NASA Image and Video Library

1969-07-28

S69-45025 (27 July 1969) --- This is the first lunar sample that was photographed in detail in the Lunar Receiving Laboratory at the Manned Spacecraft Center. The photograph shows a granular, fine-grained, mafic (iron magnesium rich) rock. At this early stage of the examination, this rock appears similar to several igneous rock types found on Earth. The scale is printed backwards due to the photographic configuration in the Vacuum Chamber. The sample number is 10003. This rock was among the samples collected by astronauts Neil A. Armstrong and Edwin E. Aldrin Jr. during their lunar surface extravehicular activity on July 20, 1969.

Progress of the LASL dry hot rock geothermal energy project

NASA Technical Reports Server (NTRS)

Smith, M. C.

1974-01-01

The possibilities and problems of extracting energy from geothermal reservoirs which do not spontaneously yield useful amounts of steam or hot water are discussed. The system for accomplishing this which is being developed first is a pressurized-water circulation loop intended for use in relatively impermeable hot rock. It will consist of two holes connected through the hot rock by a very large hydraulic fracture and connected at the surface through the primary heat exchanger of an energy utilization system. Preliminary experiments in a hole 2576 ft (0.7852 km) deep, extending about 470 ft (143 m) into the Precambrian basement rock underlying the Jemez Plateau of north-central New Mexico, revealed no unexpected difficulties in drilling or hydraulically fracturing such rock at a temperature of approximately 100 C, and demonstrated a permeability low enough so that it appeared probable that pressurized water could be contained by the basement rock. Similar experiments are in progress in a second hole, now 6701 ft (2.043 km) deep, about 1.5 miles (2.4 km) south of the first one.

The search for the cause of the low albedo of the moon

NASA Technical Reports Server (NTRS)

Gold, T.; Bilson, E.; Baron, R. L.

1975-01-01

Experimentation concerning lunar weathering and its effect on the albedo of the surface cover consisted of: (1) determination of the surface chemical composition of lunar soil and ground-up rock samples by Auger electron spectroscopy, (2) measurement of the optical albedo of these samples, and (3) proton or alpha-particle irradiation of terrestrial rock chips and rock powders and of ground-up lunar rock samples in order to determine the optical and surface chemical effect of simulated solar wind.

The 4D evolution of porosity during ongoing pressure-solution processes in NaCl using x-ray microtomography

NASA Astrophysics Data System (ADS)

Macente, Alice; Fusseis, Florian; Butler, Ian; Tudisco, Erika; Hall, Stephen; Andò, Edward

2016-04-01

Pressure-solution creep is a common deformation mechanism in the upper crust. It represents a mass transfer via dissolution-reprecipitation that critically affects the hydraulic properties of rocks. Successful management of safe radioactive storage sites in rock-salt deposits critically depends on an accurate knowledge of the hydro-mechanical behaviour of salt deposits. Despite numerous lab experiments that have been conducted, many aspects of pressure-solution are still poorly understood. There is little knowledge about the spatio-temporal evolution of porosity and permeability during pressure-solution creep. While rates of pressure-solution creep in silicates and carbonates are slow, which makes laboratory investigations of these materials impractical, compaction experiments have demonstrated that NaCl samples deform sufficiently fast to study pressure-solution creep in a lab environment at room temperature and modest loads. We present results from novel experiments that quantify the 4-dimensional (three spatial dimensions plus time) evolution of pressure-solution processes using in-situ x-ray microtomography. Our experiments are performed in custom made x-ray transparent presses. 5 mm diameter NaCl powder samples with a grain size of 250-300 μm are loaded dry into the press and pre-compacted to produce a starting aggregated material. The sample is then flooded with saturated NaCl solution and loaded uniaxially by means of a pneumatic actuator to a constant uniaxial stress. Different sample mixtures were tested, as well as different uniaxial loads. The resulting deformation of the samples is documented in 3-dimensional microtomographic datasets, acquired at regular time intervals. Image analysis allowed characterization of the microstructural evolution of the NaCl grains and the spatio-temporal distribution of porosity during ongoing mechanical and chemical compaction. The microtomography data have also been analysed with 3D Digital Image Correlation (3D-DIC or DVC) to quantify the fields of displacements in each direction, as well as volumetric and maximum shear strain fields. Following the approach described above, we have been able to quantify and characterize in 4D the evolution of pressure-solution creep and porosity distribution in relation to different sample materials and increasing uniaxial load. The presence of phyllosilicates (biotite) and more competent materials (glass beads) allowed pressure-solution to develop in a much shorter time compared to pure halite sample. The same trend is observed in samples experiencing bigger uniaxial loads (6.6 MPa v 1.6 MPa). We also found that, in the presence of phyllosilicates (biotite), pore size distribution clearly reflects the localisation of pressure-solution processes, as for natural stylolites. In the presence of glass beads, pressure-solution has a greater effect on the pore orientations rather than pore sizes. Our results extend the current understanding of the effect of pressure-solution creep on the mechanical and hydraulic properties of rocks, with implications for natural rock-salt, salt-based repository systems (nuclear and chemical waste storage) and salt mining.

[High Precision Identification of Igneous Rock Lithology by Laser Induced Breakdown Spectroscopy].

PubMed

Wang, Chao; Zhang, Wei-gang; Yan, Zhi-quan

2015-09-01

In the field of petroleum exploration, lithology identification of finely cuttings sample, especially high precision identification of igneous rock with similar property, has become one of the geological problems. In order to solve this problem, a new method is proposed based on element analysis of Laser-Induced Breakdown Spectroscopy (LIBS) and Total Alkali versus Silica (TAS) diagram. Using independent LIBS system, factors influencing spectral signal, such as pulse energy, acquisition time delay, spectrum acquisition method and pre-ablation are researched through contrast experiments systematically. The best analysis conditions of igneous rock are determined: pulse energy is 50 mJ, acquisition time delay is 2 μs, the analysis result is integral average of 20 different points of sample's surface, and pre-ablation has been proved not suitable for igneous rock sample by experiment. The repeatability of spectral data is improved effectively. Characteristic lines of 7 elements (Na, Mg, Al, Si, K, Ca, Fe) commonly used for lithology identification of igneous rock are determined, and igneous rock samples of different lithology are analyzed and compared. Calibration curves of Na, K, Si are generated by using national standard series of rock samples, and all the linearly dependent coefficients are greater than 0.9. The accuracy of quantitative analysis is investigated by national standard samples. Element content of igneous rock is analyzed quantitatively by calibration curve, and its lithology is identified accurately by the method of TAS diagram, whose accuracy rate is 90.7%. The study indicates that LIBS can effectively achieve the high precision identification of the lithology of igneous rock.

Complex Contact Angles Calculated from Capillary Rise Measurements on Rock Fracture Faces

NASA Astrophysics Data System (ADS)

Perfect, E.; Gates, C. H.; Brabazon, J. W.; Santodonato, L. J.; Dhiman, I.; Bilheux, H.; Bilheux, J. C.; Lokitz, B. S.

2017-12-01

Contact angles for fluids in unconventional reservoir rocks are needed for modeling hydraulic fracturing leakoff and subsequent oil and gas extraction. Contact angle measurements for wetting fluids on rocks are normally performed using polished flat surfaces. However, such prepared surfaces are not representative of natural rock fracture faces, which have been shown to be rough over multiple scales. We applied a variant of the Wilhelmy plate method for determining contact angle from the height of capillary rise on a vertical surface to the wetting of rock fracture faces by water in the presence of air. Cylindrical core samples (5.05 cm long x 2.54 cm diameter) of Mancos shale and 6 other rock types were investigated. Mode I fractures were created within the cores using the Brazilian method. Each fractured core was then separated into halves exposing the fracture faces. One fracture face from each rock type was oriented parallel to a collimated neutron beam in the CG-1D imaging instrument at ORNL's High Flux Isotope Reactor. Neutron radiography was performed using the multi-channel plate detector with a spatial resolution of 50 μm. Images were acquired every 60 s after a water reservoir contacted the base of the fracture face. The images were normalized to the initial dry condition so that the upward movement of water on the fracture face was clearly visible. The height of wetting at equilibrium was measured on the normalized images using ImageJ. Contact angles were also measured on polished flat surfaces using the conventional sessile drop method. Equilibrium capillary rise on the exposed fracture faces was up to 8.5 times greater than that predicted for polished flat surfaces from the sessile drop measurements. These results indicate that rock fracture faces are hyperhydrophilic (i.e., the height of capillary rise is greater than that predicted for a contact angle of zero degrees). The use of complex numbers permitted calculation of imaginary contact angles for such surfaces. This analysis yielded a continuum of contact angles (real above, and imaginary below, zero degrees) that can be used to investigate relationships with properties such surface roughness and porosity. It should be noted these are preliminary, unreplicated results and further research will be needed to verify them and refine the approach.

Magmatic evolution of Panama Canal volcanic rocks: A record of arc processes and tectonic change.

PubMed

Farris, David W; Cardona, Agustin; Montes, Camilo; Foster, David; Jaramillo, Carlos

2017-01-01

Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21-25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile element enrichments, a THI of 0.88, and a H2Ocalc of >3 wt. %. In contrast, the Miocene Pedro Miguel and Late Basalt Fm. exhibit reduced Nb-Ta anomalies, flattened REE curves, depleted fluid mobile elements, a THI of 1.45, a H2Ocalc of <1 wt. %, and plot in mid-ocean ridge/back-arc basin fields. Geochemical modeling of Miocene rocks indicates 0.5-0.1 kbar crystallization depths of hot (1100-1190°C) magmas in which most compositional diversity can be explained by fractional crystallization (F = 0.5). However, the most silicic lavas (Las Cascadas Fm.) require an additional mechanism, and assimilation-fractional-crystallization can reproduce observed compositions at reasonable melt fractions. The Canal volcanic rocks, therefore, change from hydrous basaltic pyroclastic deposits typical of mantle-wedge-derived magmas, to hot, dry bi-modal magmatism at the Oligocene-Miocene boundary. We suggest the primary reason for the change is onset of arc perpendicular extension localized to central Panama. High-resolution mapping along the Panama Canal has revealed a sequence of inward dipping maar-diatreme pyroclastic pipes, large basaltic sills, and bedded silicic ignimbrites and tuff deposits. These volcanic bodies intrude into the sedimentary Canal Basin and are cut by normal and subsequently strike-slip faults. Such pyroclastic pipes and basaltic sills are most common in extensional arc and large igneous province environments. Overall, the change in volcanic edifice form and geochemistry are related to onset of arc perpendicular extension, and are consistent with the idea that Panama arc crust fractured during collision with South America forming the observed Canal extensional zone.

Carbon-enhanced electrical conductivity during fracture of rocks

NASA Astrophysics Data System (ADS)

Roberts, J. J.; Duba, A. G.; Mathez, E. A.; Shankland, T. J.; Kinzler, R.

1999-01-01

Changes in electrical resistance during rock fracture in the presence of a carbonaceous atmosphere have been investigated using Nugget sandstone and Westerly granite. The experiments were performed in an internally heated, gas-pressure vessel with a load train that produced strain rates between 10-6 and 10-5 s-1. Samples were deformed at temperatures of 354° to 502°C and pressures of 100 to 170 MPa in atmospheres of Ar or mixtures of 95% CO2 with 5% CO or 5% CH4, compositions that are well within the field of graphite stability at the run conditions. In experiments using Nugget sandstone, resistance reached a minimum value when the maximum temperature was achieved and good electrode contact was made. The resistance then increased as the experiment continued, probably due to dry out of the sample, a change in the oxidation state of the Fe-oxide associated with the cement, or destruction of current-bearing pathways. At approximately 200-MPa end load, the rock sample failed. Plots of load and resistance versus time show several interesting features. In one experiment, for example, as the end load reached about 175 MPa, resistance stopped increasing and remained fairly constant for a period of approximately 0.5 hour. During loading, the end load displayed small decreases that were simultaneous with small decreases in resistance; when the end load (and the displacement) indicated rock failure, resistance decreased dramatically, from ˜150 MΩ to 100 MΩ. In a single experiment, the Westerly granite also showed a decrease in resistance during dilatancy. The nature and distribution of carbon in the run products were studied by electron microprobe and time-of-flight secondary-ion mass spectroscopy (TOP-SIMS). Carbon observed by mapping with the former is clearly observed on micro-cracks that, based on the microtexture, are interpreted to have formed during the deformation. The TOF-SIMS data confirm the electron-probe observations that carbon is present on fracture surfaces. These observations and experimental results lead to the hypothesis that as microfractures open in the time leading up to failure along a fracture, carbon is deposited as a continuous film on the new, reactive mineral surfaces, and this produces a decrease in resistance. Subsequent changes in resistance occur as connectivity of the initial fracture network is altered by continued deformation. Such a process may explain some electromagnetic effects associated with earthquakes.

Weathering process in Sør Rondane Mountains, East Antarctica

NASA Astrophysics Data System (ADS)

Kanamaru, T.; Suganuma, Y.; Oiwane, H.; Miura, M.; Okuno, J.; Hayakawa, H.

2016-12-01

Weathering process under the hyper-arid and hypothermal environment is a key to understand the geomorphogic process and landscape evolution in Antarctica and on Mars. A nunber of studies have focused on weathering process of basaltic rocks in Antarctica, however, the nature of the weathering process of plutonic type rock, a common rock type on the Earth, have been less focused and remain unclear. Here, we report the physical/chemical weathering process of the granitic rocks obtained from Dronning Maud Land in East Antarctica based on a multiplicity of petrological approaches. Loss on Ignition (LOI) and major element composition of the crust and core of the rock samples indicate that chemical weathering process in this area seems to be very limited. The microscopic observations and laser-Raman micro spectroscopy for thin sections from the crust and core indicate that goethite grains are formed mainly in the vein around the crust, which is consistent with the higher Fe3+/Fe2+ contrast from the core to crust. A negative correlation between the rock hardness and color strength index (CSI) values also indicate that crust of rock samples tend to less hard than core due to cracking of the rock samples and following goethite formation. On the other hand, EPMA analysis indicates that original Fe-Ti oxide grains in the core of rock samples are damaged by weathering, and altered to hematite, and to non-stoichiometric Fe-Ti compound associated with ilmenite grans in case of the higher relative height samples. These reveal that the weathering process of the plutonic rocks under the hyper-cold and hypothermal environment are mainly controlled by oxidation, including iron hydroxide formation in the veins formed by mechanical distraction, and Fe-Ti oxide alteration in rock interior.

Geohydrologic reconnaissance of the upper Potomac River basin

USGS Publications Warehouse

Trainer, Frank W.; Watkins, Frank A.

1975-01-01

The upper Potomac River basin, in the central Appalachian region in Pennsylvania, Maryland, Virginia, and West Virginia, is a humid temperate region of diverse fractured rocks. Three geohydrologic terranes, which underlie large parts of the basin, are described in terms of their aquifer characteristics and of the magnitude and duration of their base runoff: (1) fractured rock having a thin regolith, (2) fractured rock having a thick regolith, and (3) carbonate rock. Crystalline rock in the mountainous part of the Blue Ridge province and shale with tight sandstone in the folded Appalachians are covered with thin regolith. Water is stored in and moves through fairly unmodified fractures. Average transmissivity (T) is estimated to be 150 feet squared per day, and average storage coefficient (S), 0.005. Base runoff declines rapidly from its high levels during spring and is poorly sustained during the summer season of high evapotranspiration. The rocks in this geohydrologic terrane are the least effective in the basin for the development of water supplies and as a source of dry-weather streamflow. Crystalline and sedimentary rocks in the Piedmont province and in the lowland part of the Blue Ridge province are covered with thick regolith. Water is stored in and moves through both the regolith and the underlying fractured rock. Estimated average values for aquifer characteristics are T, 200 feet squared per day, and S, 0.01. Base runoff is better sustained in this terrane than in the thin-regolith terrane and on the average .is about twice as great. Carbonate rock, in which fractures have been widened selectively by solution, especially near streams, has estimated average aquifer characteristics of T, 500 feet squared per day, and S, 0.03-0.04. This rock is the most effective in the basin in terms of water supply and base runoff. Where its fractures have not been widened by solution, the carbonate rock is a fractured-rock aquifer much like the noncarbonate rock. At low values the frequency of specific capacities of wells is much the same in all rocks in the basin, but high values of specific capacity are as much as 10 times more frequent in carbonate rock than in noncarbonate rock. Nearly all the large springs and high-capacity wells in the basin are in carbonate rock. Base runoff from the carbonate rock is better sustained during dry weather and on the average is about three times as great as base runoff from fractured rock having a thin regolith. The potential role of these water-bearing terranes in water management probably lies in the local development of large water supplies from the carbonate rock and in the possible manipulation of underground storage for such purposes as providing space for artificial recharge of ground water and providing ground water to be used for the augmentation of low streamflow. The chief water-quality problems in the basin--acidic mine-drainage water in the western part of the basin, local highly mineralized ground water, and the high nitrate content of ground water in some of the densely populated parts of the basin--would probably have little adverse affect on the use of ground water for low-flow augmentation.

LUNAR SAMPLES - APOLLO XVI - JSC

NASA Image and Video Library

1975-03-18

S75-23543 (April 1972) --- This Apollo 16 lunar sample (moon rock) was collected by astronaut John W. Young, commander of the mission, about 15 meters southwest of the landing site. This rock weighs 128 grams when returned to Earth. The sample is a polymict breccia. This rock, like all lunar highland breccias, is very old, about 3,900,000,000 years older than 99.99% of all Earth surface rocks, according to scientists. Scientific research is being conducted on the balance of this sample at NASA's Johnson Space Center and at other research centers in the United States and certain foreign nations under a continuing program of investigation involving lunar samples collected during the Apollo program.

Effects of source rocks, soil features and climate on natural gamma radioactivity in the Crati valley (Calabria, Southern Italy).

PubMed

Guagliardi, Ilaria; Rovella, Natalia; Apollaro, Carmine; Bloise, Andrea; De Rosa, Rosanna; Scarciglia, Fabio; Buttafuoco, Gabriele

2016-05-01

The study, which represents an innovative scientific strategy to approach the study of natural radioactivity in terms of spatial and temporal variability, was aimed to characterize the background levels of natural radionuclides in soil and rock in the urban and peri-urban soil of a southern Italy area; to quantify their variations due to radionuclide bearing minerals and soil properties, taking into account nature and extent of seasonality influence. Its main novelty is taking into account the effect of climate in controlling natural gamma radioactivity as well as analysing soil radioactivity in terms of soil properties and pedogenetic processes. In different bedrocks and soils, activities of natural radionuclides ((238)U, (232)Th (4) K) and total radioactivity were measured at 181 locations by means of scintillation γ-ray spectrometry. In addition, selected rocks samples were collected and analysed, using a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS) and an X-Ray Powder Diffraction (XRPD), to assess the main sources of radionuclides. The natural-gamma background is intimately related to differing petrologic features of crystalline source rocks and to peculiar pedogenetic features and processes. The radioactivity survey was conducted during two different seasons with marked changes in the main climatic characteristics, namely dry summer and moist winter, to evaluate possible effects of seasonal climatic variations and soil properties on radioactivity measurements. Seasonal variations of radionuclides activities show their peak values in summer. The activities of (238)U, (232)Th and (4) K exhibit a positive correlation with the air temperature and are negatively correlated with precipitations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Shale Gas Geomechanics for Development and Performance of Unconventional Reservoirs

NASA Astrophysics Data System (ADS)

Domonik, Andrzej; Łukaszewski, Paweł; Wilczyński, Przemysław; Dziedzic, Artur; Łukasiak, Dominik; Bobrowska, Alicja

2017-04-01

Mechanical properties of individual shale formations are predominantly determined by their lithology, which reflects sedimentary facies distribution, and subsequent diagenetic and tectonic alterations. Shale rocks may exhibit complex elasto-viscoplastic deformation mechanisms depending on the rate of deformation and the amount of clay minerals, also bearing implications for subcritical crack growth and heterogeneous fracture network development. Thus, geomechanics for unconventional resources differs from conventional reservoirs due to inelastic matrix behavior, stress sensitivity, rock anisotropy and low matrix permeability. Effective horizontal drilling and hydraulic fracturing technologies are required to obtain and maintain high performance. Success of these techniques strongly depends on the geomechanical investigations of shales. An inelastic behavior of shales draws increasing attention of investigators [1], due to its role in stress relaxation between fracturing phases. A strong mechanical anisotropy in the vertical plane and a lower and more variable one in the horizontal plane are characteristic for shale rocks. The horizontal anisotropy plays an important role in determining the direction and effectiveness of propagation of technological hydraulic fractures. Non-standard rock mechanics laboratory experiments are being applied in order to obtain the mechanical properties of shales that have not been previously studied in Poland. Novel laboratory investigations were carried out to assess the creep parameters and to determine time-dependent viscoplastic deformation of shale samples, which can provide a limiting factor to tectonic stresses and control stress change caused by hydraulic fracturing. The study was supported by grant no.: 13-03-00-501-90-472946 "An integrated geomechanical investigation to enhance gas extraction from the Pomeranian shale formations", funded by the National Centre for Research and Development (NCBiR). References: Ch. Chang M. D. Zoback. 2009. Viscous creep in room-dried unconsolidated Gulf of Mexico shale (I): Experimental results. Journal of Petroleum Science and Engineering 69: 239-246.

Kinetics of the coesite to quartz transformation

USGS Publications Warehouse

Mosenfelder, J.L.; Bohlen, S.R.

1997-01-01

The survival of coesite in ultrahigh-pressure (UHP) rocks has important implications for the exhumation of subducted crustal rocks. We have conducted experiments to study the mechanism and rate of the coesite ??? quartz transformation using polycrystalline coesite aggregates, fabricated by devitrifying silica glass cylinders containing 2850H/106 Si at 1000??C and 3.6 GPa for 24h. Conditions were adjusted following synthesis to transform the samples at 700-1000??C at pressures 190-410 MPa below the quartz-coesite equilibrium boundary. Reaction proceeds via grain-boundary nucleation and interface-controlled growth, with characteristic reaction textures remarkably similar to those seen in natural UHP rocks. We infer that the experimental reaction mechanism is identical to that in nature, a prerequisite for reliable extrapolation of the rate data. Growth rates obtained by direct measurement differ by up to two orders of magnitude from those estimated by fitting a rate equation to the transformation-time data. Fitting the rates to Turnbull's equation for growth therefore yields two distinct sets of parameters with similar activation energies (242 or 269 kJ/mol) but significantly different pre-exponential constants. Extrapolation based on either set of growth rates suggests that coesite should not be preserved on geologic time scales if it reaches the quartz stability field at temperatures above 375-400??C. The survival of coesite has previously been linked to its inclusion in strong phases, such as garnet, that can sustain a high internal pressure during decompression. Other factors that may play a crucial role in preservation are low fluid availability - possibly even less than that of our nominally "dry" experiments - and the development of transformation stress, which inhibits nucleation and growth. These issues are discussed in the context of our experiments as well as recent observations from natural rocks. ?? 1997 Elsevier Science B.V.

Effects of leachate on geotechnical characteristics of sandy clay soil

NASA Astrophysics Data System (ADS)

Harun, N. S.; Ali, Z. Rahman; Rahim, A. S.; Lihan, T.; Idris, R. M. W.

2013-11-01

Leachate is a hazardous liquid that poses negative impacts if leaks out into environments such as soil and ground water systems. The impact of leachate on the downgraded quality in terms of chemical characteristic is more concern rather than the physical or mechanical aspect. The effect of leachate on mechanical behaviour of contaminated soil is not well established and should be investigated. This paper presents the preliminary results of the effects of leachate on the Atterberg limit, compaction and shear strength of leachate-contaminated soil. The contaminated soil samples were prepared by mixing the leachate at ratiosbetween 0% and 20% leachate contents with soil samples. Base soil used was residual soil originated from granitic rock and classified as sandy clay soil (CS). Its specific gravity ranged between 2.5 and 2.64 with clay minerals of kaolinite, muscovite and quartz. The field strength of the studied soil ranged between 156 and 207 kN/m2. The effects of leachate on the Atterberg limit clearly indicated by the decrease in liquid and plastic limit values with the increase in the leachate content. Compaction tests on leachate-contaminated soil caused the dropped in maximum dry density, ρdry and increased in optimum moisture content, wopt when the amount of leachate was increased between 0% and 20%. The results suggested that leachate contamination capable to modify some geotechnical properties of the studied residual soils.

Rapid Active Sampling Package

NASA Technical Reports Server (NTRS)

Peters, Gregory

2010-01-01

A field-deployable, battery-powered Rapid Active Sampling Package (RASP), originally designed for sampling strong materials during lunar and planetary missions, shows strong utility for terrestrial geological use. The technology is proving to be simple and effective for sampling and processing materials of strength. Although this originally was intended for planetary and lunar applications, the RASP is very useful as a powered hand tool for geologists and the mining industry to quickly sample and process rocks in the field on Earth. The RASP allows geologists to surgically acquire samples of rock for later laboratory analysis. This tool, roughly the size of a wrench, allows the user to cut away swaths of weathering rinds, revealing pristine rock surfaces for observation and subsequent sampling with the same tool. RASPing deeper (.3.5 cm) exposes single rock strata in-situ. Where a geologist fs hammer can only expose unweathered layers of rock, the RASP can do the same, and then has the added ability to capture and process samples into powder with particle sizes less than 150 microns, making it easier for XRD/XRF (x-ray diffraction/x-ray fluorescence). The tool uses a rotating rasp bit (or two counter-rotating bits) that resides inside or above the catch container. The container has an open slot to allow the bit to extend outside the container and to allow cuttings to enter and be caught. When the slot and rasp bit are in contact with a substrate, the bit is plunged into it in a matter of seconds to reach pristine rock. A user in the field may sample a rock multiple times at multiple depths in minutes, instead of having to cut out huge, heavy rock samples for transport back to a lab for analysis. Because of the speed and accuracy of the RASP, hundreds of samples can be taken in one day. RASP-acquired samples are small and easily carried. A user can characterize more area in less time than by using conventional methods. The field-deployable RASP used a Ni/Cad rechargeable battery. Power usage was less than 1 Wh/ cm3 even when sampling strong basalts, so many samples could be taken on a single battery charge.

Sierra Nevada Rock Glaciers: Biodiversity Refugia in a Warming World?

NASA Astrophysics Data System (ADS)

Millar, C. I.; Westfall, R. D.

2007-12-01

Rock glaciers and related periglacial rock-ice features (RIFs) are common landforms in high, dry mountain ranges, and widely distributed throughout canyons of the Sierra Nevada, California, USA (Millar & Westfall, in press). Due to insulating rock carapaces, active rock glaciers (ice-cored) have been documented to maintain ice longer, and thus contribute to more enduring hydrologic output, under past warming climates than typical ice glaciers. This function has been suggested for the coming century. We propose a broader hydrologic and ecologic role for RIFs as temperatures rise in the future. For the Sierra Nevada, we suggest that canyons with either active or relict RIFs (Holocene and Pleistocene) maintain water longer and distribute water more broadly than canyons that were scoured by ice glaciers and are defined by primary river and lake systems. RIFs provide persistent, distributed water for extensive wetland habitat, rare in these otherwise barren, high, and dry locations. We mapped and assessed the area of wetlands surrounding active and relict RIFs from the central eastern Sierra Nevada; from these we delineated wetland vegetation community types and recorded plant species found in RIF-supported wetlands. Mid-elevation RIFs, likely inactive or with transient ice, develop soil patches on their rock matrix. At the Barney Rock Glacier (Duck Pass, Mammoth Crest), we inventoried plant species on all soil patches, and measured cover for each species per patch and total plant cover for the rock glacier. RIF landforms also appear to support high-elevation mammals. We show that American beaver (Castor canadensis) is associated with canyons dominated by active or relict RIFs and propose that the articulating, persistent, and distributed nature of streams makes dam-building easier than other canyons. Beavers further contribute to maintaining water and creating wetland habitat in upper watersheds by engineering ponds and marshes, and contributing to riparian extent. We also mapped 125 discrete locations of American pika (Ochotona princeps) and found a strong association of pika presence with active and relict RIFs, in particular cirque rock glaciers, valley rock glaciers, and boulder streams. Using the PRISM climate model and a small network of temperature dataloggers from RIF habitats, we present a climate envelope for the pika habitats we surveyed. We propose that the large area of RIFs in the Sierra Nevada over a range of elevations could provide extensive habitat for pika in the warming future. RIFs in general are a group of landforms little studied in high mountains of western North America but of potential increasing importance to hydrologic and ecologic function as climate warms in the future. Millar, C.I. and R.D. Westfall. In press. Rock glaciers and periglacial rock-ice features in the Sierra Nevada; Classification, distribution, and climate relationships. Quaternary International.

Seasonal variation of copper and zinc concentrations in the oyster Saccostrea cuccullata from the Dampier Archipelago, Western Australia: implications for pollution monitoring.

PubMed

Talbot, V

1986-12-01

The intertidal rock oyster Saccostrea cuccullata, sampled at eight sites on eight occasions over a 1-year period, contained mean Cu and Zn concentrations ranging between 34 and 267 and 206 and 4078 mg kg-1 dry weight, respectively. In the study area, Cu and Zn emanate from sewage and boat slips (antifouling paints), while Zn probably also originates from coolant water from an electricity power generating station and iron ore exporting facilities. Highest oyster wet weight, Cu and Zn concentrations and loads occurred in January (spawning period), indicating that metal variation was not reciprocating wet weight. Lowest metal concentrations and loads occurred in October (period of onset of gametogenesis), while lowest wet weight occurred in April (post-spawning period). No significant (P less than 0.001) variation in the wet to dry weight ratio was noted temporally. However, significant, though slight, variation was noted between polluted and unpolluted oysters. Results of this study indicate that pollution control monitoring programs should consider: seasonal variation of metal concentrations; portion of the year during which standards are exceeded; oyster size and availability for human consumption; suitability of standards where shellfish are not consumed as a staple diet; appropriate size indicies which can be used for selecting specimens for intersite comparisons; wet to dry weight calculations: techniques, spatial and temporal variations; and the physical dynamics of sites used.

The apollo 15 lunar samples: A preliminary description

USGS Publications Warehouse

Gast, P.W.; Phinney, W.C.; Duke, M.B.; Silver, L.T.; Hubbard, N.J.; Heiken, G.H.; Butler, P.; McKay, D.S.; Warner, J.L.; Morrison, D.A.; Horz, F.; Head, J.; Lofgren, G.E.; Ridley, W.I.; Reid, A.M.; Wilshire, H.; Lindsay, J.F.; Carrier, W.D.; Jakes, P.; Bass, M.N.; Brett, P.R.; Jackson, E.D.; Rhodes, J.M.; Bansal, B.M.; Wainwright, J.E.; Parker, K.A.; Rodgers, K.V.; Keith, J.E.; Clark, R.S.; Schonfeld, E.; Bennett, L.; Robbins, Martha M.; Portenier, W.; Bogard, D.D.; Hart, W.R.; Hirsch, W.C.; Wilkin, R.B.; Gibson, E.K.; Moore, C.B.; Lewis, C.F.

1972-01-01

Samples returned from the Apollo 15 site consist of mare basalts and breccias with a variety of premare igneous rocks. The mare basalts are from at least two different lava flows. The bulk chemical compositions and textures of these rocks confirm the previous conclusion that the lunar maria consist of a series of extrusive volcanic rocks that are rich in iron and poor in sodium. The breccias contain abundant clasts of anorthositic fragments along with clasts of basaltic rocks much richer in plagioclase than the mare basalts. These two rock types also occur as common components in soil samples from this site. The rocks and soils from both the front and mare region exhibit a variety of shock characteristics that can best be ascribed to ray material from the craters Aristillus or Autolycus.

Quantitative fabric analysis of eclogite facies mylonites: texture and microtomography

NASA Astrophysics Data System (ADS)

Gomez Barreiro, J.; Voltolini, M.; Martinez-Catalan, J. R.; Benitez-Perez, J. M.; Diez-fernandez, R.; Wenk, H. R.; Vogel, S. C.; Mancini, L.

2014-12-01

Understanding the flow of rock deformed under eclogite facies conditions is crucial to constraint the dynamics of a subducting slab. Prograde metamorphism during burial in a subduction zone proceeds across several lithologies, resulting in heterogeneous eclogitization and potentially different processes. In order to explore the expression of such a variety in terms of a deformative fabric, we have analyzed texture and shape fabric of eclogites and eclogitic orthogneisses from the Malpica-Tui unit (NW Spain). We explore the same rock volumes with TOF-neutron diffraction (HIPPO @ LANSCE) and synchrotron microtomography (SYRMEP @Elettra). Orientation distribution functions were extracted after Rietveld refinement in MAUD and morphometric data (size, aspect ratio, orientation) were obtained after image processing with FIJI, Blob3D and MATLAB. Shape fabric reflects the macroscopic foliation and lineation and correlates with texture. Garnet fabric is particularly important because of the rheological implications of its mechanical behavior. Garnet shows little elongation in both samples, and texture is significant, what probably points to a relatively dry deformative environment, with diffusion-assisted dislocation. This eclogites could represent a rigidification stage in the subduction channel preserved during the exhumation at high-P and high-T documented in the Malpica-Tui unit during the Variscan orogeny.

The United States Polar Rock Repository: A geological resource for the Earth science community

USGS Publications Warehouse

Grunow, Annie M.; Elliot, David H.; Codispoti, Julie E.

2007-01-01

The United States Polar Rock Repository (USPRR) is a U. S. national facility designed for the permanent curatorial preservation of rock samples, along with associated materials such as field notes, annotated air photos and maps, raw analytic data, paleomagnetic cores, ground rock and mineral residues, thin sections, and microfossil mounts, microslides and residues from Polar areas. This facility was established by the Office of Polar Programs at the U. S. National Science Foundation (NSF) to minimize redundant sample collecting, and also because the extreme cold and hazardous field conditions make fieldwork costly and difficult. The repository provides, along with an on-line database of sample information, an essential resource for proposal preparation, pilot studies and other sample based research that should make fieldwork more efficient and effective. This latter aspect should reduce the environmental impact of conducting research in sensitive Polar Regions. The USPRR also provides samples for educational outreach. Rock samples may be borrowed for research or educational purposes as well as for museum exhibits.

Herbal dryer: drying of ginger (zingiber officinale) using tray dryer

NASA Astrophysics Data System (ADS)

Haryanto, B.; Hasibuan, R.; Alexander; Ashari, M.; Ridha, M.

2018-02-01

Drying is widely used as a method to preserve food because of its convenience and affordability. Drying of ginger using tray dryer were carried out at various drying conditions, such as air-drying flow, air-drying temperature, and sample dimensions, to achieve the highest drying rate. Samples with various dimensions were placed in the tray dryer and dried using various air-drying flow and temperatures. The weights of samples were observed every 3 minutes interval. Drying was stopped after three times of constant weighing. Data of drying was collected to make the drying curves. Drying curves show that the highest drying rate is achieved using highest air flow and temperature.

LUNAR SAMPLES - APOLLO XI - MSC

NASA Image and Video Library

1969-07-28

S69-45009 (27 July 1969) --- This is the first lunar sample that was photographed in detail in the Lunar Receiving Laboratory (LRL) at the Manned Spacecraft Center (MSC). The photograph shows a granular, fine-grained, mafic (iron magnesium rich) rock. At this early stage of the examination, this rock appears similar to several igneous rock types found on Earth. The scale is printed backwards due to the photographic configuration in the Vacuum Chamber. The sample number is 10003. This rock was among the samples collected by astronauts Neil A. Armstrong and Edwin E. Aldrin Jr. during their lunar surface extravehicular activity (EVA) on July 20, 1969.

Lead isotopes and trace metals in dust at Yucca Mountain

USGS Publications Warehouse

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

2008-01-01

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

Lunar Samples - Apollo 12

NASA Image and Video Library

1969-11-26

S69-60294 (26 Nov. 1969) --- One of the first views of the Apollo 12 lunar rocks is this photograph of the open sample return container. The large rock is approximately 7 1/2 inches across and is larger than any rock brought back to Earth by the crew of the Apollo 11 lunar landing mission. Two of the rocks in the first container are crystalline and generally lighter in color than those returned on the first lunar landing. The rocks in this box are medium charcoal brown/gray in color.

Investigation of rock samples by neutron diffraction and ultrasonic sounding

NASA Astrophysics Data System (ADS)

Burilichev, D. E.; Ivankina, T. I.; Klima, K.; Locajicek, T.; Nikitin, A. N.; Pros, Z.

2000-03-01

The interpretation of large-scale geophysical anisotropies largely depends upon the knowledge of rock anisotropies of any kind (compositions, foliations, grain shape, physical properties). Almost all physical rock properties (e.g. elastic, thermal, magnetic properties) are related to the textures of the rock constituents since they are anisotropic for the single crystal. Although anisotropy determinations are numerous, systematic investigations are scarce. Therefore, several rock samples with different microfabrics were selected for texture analysis and to determine its P-wave distributions at various confining pressures.

The paradox of a wet (high H2O) and dry (low H2O/Ce) mantle: High water concentrations in mantle garnet pyroxenites from Hawaii

NASA Astrophysics Data System (ADS)

Bizimis, M.; Peslier, A. H.

2013-12-01

Water dissolved as trace amounts in anhydrous minerals has a large influence on the melting behavior and physical properties of the mantle. The water concentration of the oceanic mantle is inferred from the analyses of MORB and OIB [1], but there is little data from actual mantle samples. Moreover, enriched mineralogies (pyroxenites, eclogites) are thought as important sources of heterogeneity in the mantle, but their water concentrations and their effect on the water budget and cycling in the mantle are virtually unknown. We analyzed by FTIR water concentrations in garnet clinopyroxenite xenoliths from Salt Lake Crater, Oahu, Hawaii. These pyroxenites are high-pressure (>20kb) crystal fractionates from alkalic melts. The clinopyroxenes (cpx) have 260 to 576 ppm wt. H2O, with the least differentiated samples (Mg#>0.8) in the 400-500 ppm range. Orthopyroxene (opx) contain 117-265 ppm H2O, about half of that of cpx, consistent with other natural sample studies, but lower than experimental cpx/opx equilibrium data. These pyroxenite cpx and opx water concentrations are at the high-end of on-and off-craton peridotite xenolith concentrations and megacrysts from kimberites [2] and those of Hawaiian spinel peridotites. In contrast, garnet has extremely low water contents (<5ppm H2O). There is no correlation between water in cpx and lithophile element concentrations. Phlogopite is present in some samples, and its modal abundance shows a positive correlation in Mg# with cpx, implying equilibrium. However, there is no correlation between water concentrations and the presence of phlogopite. These data imply that cpx and opx water concentrations may be buffered by phlogopite crystallization. Reconstructed bulk rock pyroxenite water concentrations (not including phlogopite, i.e. minimum) range from 200-460 ppm (average 331× 75 ppm), significantly higher than water estimates for the MORB source (50-200 ppm), but in the range of E-MORB, OIB and the source of rejuvenated Hawaiian magmas [1,3]. The average bulk rock pyroxenite H2O/Ce is 69 × 35, lower than estimates of the MORB source (~150) or FOZO, C (200-250) mantle component, but consistent with 'dry' EM sources (<100) [1]. These data suggest that a metasomatized, refertilized oceanic lithosphere that contains a pyroxenite component (e.g. in the lower part of an oceanic plate, where ascending melts can become trapped and crystallize), will have both higher water concentrations and low H2O/Ce, and may contribute to EM-type OIB sources, like that of Samoan basalts [5]. Therefore, a low H2O/Ce mantle source may not necessarily be 'dry'. [1] Dixon et al., 2002, Nature 420, 385-389. [2] Peslier, 2010 JVGR 197, 239-258. [3] Dixon et al., 1997 JP 38, 911-939. [4] O'Leary et al. 2010 EPSL 297, 111-120. [5] Workman et al., 2006 EPSL 241, 932 - 951.

Structural analysis of Precambrian rocks at the Hot Dry Rock Site at Fenton Hill, New Mexico

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

Burns, K.L.; Potter, R.M.

1995-01-01

The subcrop of basement rock at Fenton HIll comprises Precambrian gneiss, schist, amphibolite, pegmatite, and granitoids with affinities in metamorphic and structural history to surface outcrops in the Tusas and Picuris Ranges. Televiewer measurements of structures were analyzed by taking advantage of the spatial continuity of foliations. Folds in the foliation are predominantly conical forms due to interference between structures formed in F2 and F3 tectonic events. Field observations of outcrops in the Picuris Range show that the fractures are predominantly an X-T network controlled by the lithological layering, and statistical evidence indicates that this layer-controlled network persists to depthmore » at Fenton Hill.« less

Use of overburden rocks from open-pit coal mines and waste coals of Western Siberia for ceramic brick production with a defect-free structure

NASA Astrophysics Data System (ADS)

Stolboushkin, A. Yu; Ivanov, A. I.; Storozhenko, G. I.; Syromyasov, V. A.; Akst, D. V.

2017-09-01

The rational technology for the production of ceramic bricks with a defect-free structure from coal mining and processing wastes was developed. The results of comparison of physical and mechanical properties and the structure of ceramic bricks manufactured from overburden rocks and waste coal with traditional for semi-dry pressing mass preparation and according to the developed method are given. It was established that a homogeneous, defect-free brick texture obtained from overburden rocks of open-pit mines and waste coal improves the quality of ceramic wall materials produced by the method of compression molding by more than 1.5 times compared to the brick with a traditional mass preparation.

A Mars Sample Return Sample Handling System

NASA Technical Reports Server (NTRS)

Wilson, David; Stroker, Carol

2013-01-01

We present a sample handling system, a subsystem of the proposed Dragon landed Mars Sample Return (MSR) mission [1], that can return to Earth orbit a significant mass of frozen Mars samples potentially consisting of: rock cores, subsurface drilled rock and ice cuttings, pebble sized rocks, and soil scoops. The sample collection, storage, retrieval and packaging assumptions and concepts in this study are applicable for the NASA's MPPG MSR mission architecture options [2]. Our study assumes a predecessor rover mission collects samples for return to Earth to address questions on: past life, climate change, water history, age dating, understanding Mars interior evolution [3], and, human safety and in-situ resource utilization. Hence the rover will have "integrated priorities for rock sampling" [3] that cover collection of subaqueous or hydrothermal sediments, low-temperature fluidaltered rocks, unaltered igneous rocks, regolith and atmosphere samples. Samples could include: drilled rock cores, alluvial and fluvial deposits, subsurface ice and soils, clays, sulfates, salts including perchlorates, aeolian deposits, and concretions. Thus samples will have a broad range of bulk densities, and require for Earth based analysis where practical: in-situ characterization, management of degradation such as perchlorate deliquescence and volatile release, and contamination management. We propose to adopt a sample container with a set of cups each with a sample from a specific location. We considered two sample cups sizes: (1) a small cup sized for samples matching those submitted to in-situ characterization instruments, and, (2) a larger cup for 100 mm rock cores [4] and pebble sized rocks, thus providing diverse samples and optimizing the MSR sample mass payload fraction for a given payload volume. We minimize sample degradation by keeping them frozen in the MSR payload sample canister using Peltier chip cooling. The cups are sealed by interference fitted heat activated memory alloy caps [5] if the heating does not affect the sample, or by crimping caps similar to bottle capping. We prefer cap sealing surfaces be external to the cup rim to prevent sample dust inside the cups interfering with sealing, or, contamination of the sample by Teflon seal elements (if adopted). Finally the sample collection rover, or a Fetch rover, selects cups with best choice samples and loads them into a sample tray, before delivering it to the Earth Return Vehicle (ERV) in the MSR Dragon capsule as described in [1] (Fig 1). This ensures best use of the MSR payload mass allowance. A 3 meter long jointed robot arm is extended from the Dragon capsule's crew hatch, retrieves the sample tray and inserts it into the sample canister payload located on the ERV stage. The robot arm has capacity to obtain grab samples in the event of a rover failure. The sample canister has a robot arm capture casting to enable capture by crewed or robot spacecraft when it returns to Earth orbit

Composition, physical properties and drying characteristics of seed oil of Citrullus lanatus

NASA Astrophysics Data System (ADS)

Idris, S. A.; Rashidi, A. R.; Muhammad, A.; Abdullah, M.; Elham, O. S. J.; Mamat, M. S.

2017-09-01

A study to investigate the effect of different drying methods for the pre-treatment process on the quality and quantity of oil extracted from Citrulllus lanatus seeds was conducted. The red type Citrulllus lanatus seeds from local supermarket in Shah Alam is used in this experiment. The amount of seed was divided into two portions; one portion was subjected to sun drying while the other portion was subjected to oven drying (at a temperature of 70°C). After the drying process, the seeds were ground in a laboratory grinder to turn them into powder. The ground seeds then will be fed to Supercritical Carbon Dioxide unit (SC-CO2) for extraction. Once the extracted oil is obtained, it will be analysed by using Gas Chromatography and Mass Spectrometer (GC-MS). Results indicated that the amount of the moisture content from the sun-dried was lower compared to oven-dried. The results also indicated that, there were no significant difference in the quantity of oil obtained from both samples of oven-dried and sun-dried. However, the acid value and other component content in the sample were higher in the sun-dried sample relative to the oven-dried sample. Linoleic acid is the only compound that was found in the oven-dried sample, whereas linoleic acid and oleic acid were found in the sun-dried sample. Based on the results, it shows that the drying effect were important when the quality of oil was to be considered. The other compounds like Naphtalenol, 9-17-Octadecadeinal, 2-Chloroethyl linoleate, and Carboxin also are found in the sun-dried sample. Other that that, drying method does not give any effect to the physical appearance of the extracted oil, as similar color and other physical appearance was produced by the both sample.

Determining inert content in coal dust/rock dust mixture

DOEpatents

Sapko, Michael J.; Ward, Jr., Jack A.

1989-01-01

A method and apparatus for determining the inert content of a coal dust and rock dust mixture uses a transparent window pressed against the mixture. An infrared light beam is directed through the window such that a portion of the infrared light beam is reflected from the mixture. The concentration of the reflected light is detected and a signal indicative of the reflected light is generated. A normalized value for the generated signal is determined according to the relationship .phi.=(log i.sub.c `log i.sub.co) / (log i.sub.c100 -log i.sub.co) where i.sub.co =measured signal at 0% rock dust i.sub.c100 =measured signal at 100% rock dust i.sub.c =measured signal of the mixture. This normalized value is then correlated to a predetermined relationship of .phi. to rock dust percentage to determine the rock dust content of the mixture. The rock dust content is displayed where the percentage is between 30 and 100%, and an indication of out-of-range is displayed where the rock dust percent is less than 30%. Preferably, the rock dust percentage (RD%) is calculated from the predetermined relationship RD%=100+30 log .phi.. where the dust mixture initially includes moisture, the dust mixture is dried before measuring by use of 8 to 12 mesh molecular-sieves which are shaken with the dust mixture and subsequently screened from the dust mixture.

The quantitative studies on gas explosion suppression by an inert rock dust deposit.

PubMed

Song, Yifan; Zhang, Qi

2018-07-05

The traditional defence against propagating gas explosions is the application of dry rock dust, but not much quantitative study on explosion suppression of rock dust has been made. Based on the theories of fluid dynamics and combustion, a simulated study on the propagation of premixed gas explosion suppressed by deposited inert rock dust layer is carried out. The characteristics of the explosion field (overpressure, temperature, flame speed and combustion rate) at different deposited rock dust amounts are investigated. The flame in the pipeline cannot be extinguished when the deposited rock dust amount is less than 12 kg/m 3 . The effects of suppressing gas explosion become weak when the deposited rock dust amount is greater than 45 kg/m 3 . The overpressure decreases with the increase of the deposited rock dust amounts in the range of 18-36 kg/m 3 and the flame speed and the flame length show the same trends. When the deposited rock dust amount is 36 kg/m 3 , the overpressure can be reduced by 40%, the peak flame speed by 50%, and the flame length by 42% respectively, compared with those of the gas explosion of stoichiometric mixture. In this model, the effective raised dust concentrations to suppress explosion are 2.5-3.5 kg/m 3 . Copyright © 2018 Elsevier B.V. All rights reserved.

The effect of grain size and cement content on index properties of weakly solidified artificial sandstones

NASA Astrophysics Data System (ADS)

Atapour, Hadi; Mortazavi, Ali

2018-04-01

The effects of textural characteristics, especially grain size, on index properties of weakly solidified artificial sandstones are studied. For this purpose, a relatively large number of laboratory tests were carried out on artificial sandstones that were produced in the laboratory. The prepared samples represent fifteen sandstone types consisting of five different median grain sizes and three different cement contents. Indices rock properties including effective porosity, bulk density, point load strength index, and Schmidt hammer values (SHVs) were determined. Experimental results showed that the grain size has significant effects on index properties of weakly solidified sandstones. The porosity of samples is inversely related to the grain size and decreases linearly as grain size increases. While a direct relationship was observed between grain size and dry bulk density, as bulk density increased with increasing median grain size. Furthermore, it was observed that the point load strength index and SHV of samples increased as a result of grain size increase. These observations are indirectly related to the porosity decrease as a function of median grain size.

The effect of syntectonic hydration on rock strength, fabric evolution, and polycrystalline flow in mafic lower continental crust rocks

NASA Astrophysics Data System (ADS)

Getsinger, A.; Hirth, G.

2014-12-01

Strain localization is significantly enhanced by the influx of fluid; however, processes associated with deformation in polycrystalline material, fluid infiltration, and the evolution of creep processes and rock fabric with increasing strain localization are not well constrained for many lower crust lithologies. We combine field and experimental observations of mafic rocks deforming at lower crust pressure, temperature, and water conditions to examine strain localization processes associated with the influx of fluid, strength dependence of fabric evolution, and flow law parameters for amphibolite. General shear experiments were conducted in a Griggs rig on powdered basalt (≤5 µm starting grain size) with up to 1 wt% water at lower continental crust conditions (750˚ to 850˚C, 1GPa). Amphibole formed during deformation exhibits both a strong shape preferred orientation (SPO) and lattice preferred orientation (LPO). With increasing strain, the amphibole (and clinopyroxene) LPO strengthens and rotates to [001] maximum aligned sub-parallel to the flow direction and SPO, which indicates grain rotation during deformation. Plagioclase LPO increases from random to very weak in samples deformed to high strain. As the amphibole LPO rotates and strengthens, the mechanical strength decreases. The correlation of the SPO and LPO coupled with the rheological evidence for diffusion creep (n ≈ 1.5) indicates that the amphibole fabric results from grain growth and rigid grain rotation during deformation. The coevolution of LPO (and grain rotation) and mechanical weakening coupled with the absence of grain size reduction in our samples suggests that strength depends on the formation of a strong mineral LPO. Both our field and experimental data demonstrate that fluid intrusion into the mafic lower crust initiates syn-deformational, water-consuming reactions, creating a rheological contrast between wet and dry lithologies that promotes strain localization. Additionally, the rheology of both naturally deformed amphibolite shear zones and our fine-grained experimental amphibolite is comparable to that predicted using flow laws for wet anorthite. Thus, both our experimental and field analyses indicate that wet plagioclase rheology provides a good constraint on the strength of hydrated lower continental crust.

Investigating the effects of high temperature and a deep SMTZ on rock magnetic properties at Site C0023, IODP Expedition 370

NASA Astrophysics Data System (ADS)

Kars, M. A. C.; Henkel, S.

2017-12-01

In 2016, International Ocean Discovery Program (IODP) Expedition 370 drilled Site C0023 in the Nankai Trough, off Cape Muroto (Shikoku Island, Japan, NW Pacific Ocean). The aim of this expedition was to explore the limits of life in the deep subseafloor sediments in a high temperature environment (up to 120°C), and to investigate, among other objectives, the processes at the biotic-abiotic transition. A deep sulfate-methane transition zone (SMTZ) was identified between 630 and 750 meters below sea floor (mbsf). Based on the magnetic data profiles and results from previous ODP expeditions in the area, four magnetic zones were defined mostly reflecting changes in detrital supply and alteration/diagenetic features.Here, a rock magnetic study is conducted in order to document the downhole changes in magnetic properties and magnetic mineralogy (content, grain size and composition of the magnetic mineral assemblage) related to post-depositional diagenetic processes from 200 to 1100 mbsf, with a focus on the deep SMTZ. Natural remanent magnetization and its alternating-field demagnetization, magnetic susceptibility and acquisition of isothermal remanent magnetization are measured on 225 discrete samples for concentration and composition of the magnetic assemblage. Hysteresis properties and first order reversal curves are measured on respective dry powders for magnetic grain size study and composition of the magnetic assemblage. The preliminary rock magnetic results are presented and discussed based on the shipboard inorganic geochemical data.

Synthesis and characterization of nanocrystalline mesoporous zirconia using supercritical drying.

PubMed

Tyagi, Beena; Sidhpuria, Kalpesh; Shaik, Basha; Jasra, Raksh Vir

2006-06-01

Synthesis of nano-crystalline zirconia aerogel was done by sol-gel technique and supercritical drying using n-propanol solvent at and above supercritical temperature (235-280 degrees C) and pressure (48-52 bar) of n-propanol. Zirconia xerogel samples have also been prepared by conventional thermal drying method to compare with the super critically dried samples. Crystalline phase, crystallite size, surface area, pore volume, and pore size distribution were determined for all the samples in detail to understand the effect of gel drying methods on these properties. Supercritical drying of zirconia gel was observed to give thermally stable, nano-crystalline, tetragonal zirconia aerogels having high specific surface area and porosity with narrow and uniform pore size distribution as compared to thermally dried zirconia. With supercritical drying, zirconia samples show the formation of only mesopores whereas in thermally dried samples, substantial amount of micropores are observed along with mesopores. The samples prepared using supercritical drying yield nano-crystalline zirconia with smaller crystallite size (4-6 nm) as compared to higher crystallite size (13-20 nm) observed with thermally dried zirconia.

Experimental replacement of calcium carbonates by fluorite: high volume changes and porosity generation

NASA Astrophysics Data System (ADS)

Trindade Pedrosa, Elisabete; Putnis, Andrew

2015-04-01

Pseudomorphic mineral replacement reactions are a common phenomena in nature, and often described as interface-coupled dissolution-reprecipitation processes. The generation of porosity is a key factor for its progression since it creates the pathway for fluid infiltration towards an ongoing reaction front. The generation of porosity depends on two key factors: the molar volume differences between parent and product phase, and the relative solubilities of the parent and product in the fluid at the mineral-fluid interface (Pollok et al., 2011). Jamtveit et al., (2009) demonstrated that the permeability of the parent rock may also be enhanced by the development of fractures as a response to stresses generated by local volume changes at the reaction interface, which in turn increases the reaction rate. The replacement of calcite (CaCO3) by fluorite (CaF2) involves a molar volume decrease of 33.5 %. If indeed high volume changes generate high local stresses, a fragmentation process is expected to be driven by this replacement reaction. To test this hypothesis, a number of hydrothermal experiments were performed. Small cubes of calcite rock (Carrara marble), and single crystals of calcite were used as parent materials. Two fluoride solutions (ammonium fluoride and sodium fluoride) were used as reactants. Samples were reacted at temperatures up to 200°C for various times and quenched to room temperature. After drying, samples were mounted in epoxy holders, cross sections through the centre of the samples were cut and polished, and analysed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron microprobe analysis (EMP). The replacement end product of all experiments was confirmed to be fluorite. In every case the external shape of the samples was perfectly maintained. No reaction induced fracturing was visible in any of the samples (rock or single crystals) although the texture of the replaced material was quite complex, often with a 'V' shaped reaction front. The main difference between single crystals and rock was that in the former, grain boundaries were rapid transport pathways for fluid infiltration resulting in the precipitation of fluorite within the sample at locations further from the main reaction front. The porosity formed was very high and complex, its texture depending on the shape and orientation of the replaced material. Very large hollow spaces with diameter >30 μm formed in several samples. In this system the large volume decrease is accommodated by a high porosity rather than fracturing. Jamtveit B., Putnis C.V. & Malthe-Sørenssen A. (2009). Reaction induced fracturing during replacement processes. Contrib. Min. Pet., 157 127-133 Pollok K., Putnis C.V. & Putnis A. (2011) Mineral replacement reactions in solid solution-aqueous solution systems: Volume changes, reaction paths and end points using the example of model salt systems. Am. J. Sci., 311, 211-236

A comparison of freeze-drying and oven-drying preparation methods for bulk and compound-specific carbon stable isotope analyses: examples using the benthic macroinvertebrates Stenopsyche marmorata and Epeorus latifolium.

PubMed

Akamatsu, Fumikazu; Suzuki, Yaeko; Kato, Yoshikazu; Yoshimizu, Chikage; Tayasu, Ichiro

2016-01-15

Carbon stable isotope analysis of bulk samples and fatty acids is an established method for tracing carbon flow pathways and reconstructing trophic interactions, but there is no consensus on which sample drying method should be used for sample preparation. The aim of this study was to determine if freeze-drying and oven-drying treatments used to prepare samples of the benthic macroinvertebrates Stenopsyche marmorata and Epeorus latifolium for bulk and fatty-acid-specific carbon stable isotope analysis yield different isotopic ratio values. Five individuals each from two species were split in half; one half was freeze-dried and the other half was oven-dried. The samples were ground and the δ(13)C values of the bulk samples and eight fatty acids were measured following combustion using an isotope ratio mass spectrometer coupled to an elemental analyzer or gas chromatography system. The mean difference in the bulk and fatty acid δ(13)C values between freeze-dried and oven-dried samples was small (≤0.1‰ in both cases), although relatively large variations were observed in individual fatty-acid-specific δ(13)C values (maximum of ≤0.9 ‰). There were no significant differences in either bulk sample or fatty-acid-specific δ(13)C values between freeze-dried or oven-dried samples of the same species. Freeze-drying and oven-drying are equally acceptable methods for preparing freshly caught S. marmorata and E. latifolium samples for bulk and fatty-acid-specific carbon stable isotope analyses. Copyright © 2015 John Wiley & Sons, Ltd.

Prospects for the commercial development of hot dry rock geothermal energy in New Mexico

NASA Astrophysics Data System (ADS)

Duchane, D. V.; Goff, F.

A vast store of energy is available to the world in the form of hot dry rock (HDR) which exists almost everywhere beneath the surface of the earth. The Los Alamos National Laboratory has developed technology to mine the heat from HDR by using techniques developed in the petroleum industry. In practice, an artificial reservoir is created in the hot rock and water is circulated through the reservoir to extract the thermal energy and bring it to the surface. There are virtually no adverse environmental effects from an HDR plant when the system is operated in a closed-loop mode with the process water continually recirculated. An experimental plant at Fenton Hill, NM is now undergoing long-term testing to demonstrate that energy can be obtained from HDR on a sustained basis with operational procedures which are readily adaptable to industry. Significant HDR resources exist in the state of New Mexico. Resources in the Valles Caldera, Zuni Uplift, and Rio Grande Rift have been evaluated in detail. Studies indicate that it should be possible to economically develop high grade HDR resources with technology available today. As advanced concepts for developing and operating HDR systems are investigated, even more widespread utilization of the technology will be commercially feasible.

Rock physics properties of some lunar samples

NASA Technical Reports Server (NTRS)

Warren, N.; Trice, R.; Anderson, O. L.; Soga, N.

1973-01-01

Linear strains and acoustic velocity data for lunar samples under uniaxial and hydrostatic loading are presented. Elastic properties are presented for 60335,20; 15555,68; 15498,23; and 12063,97. Internal friction data are summarized for a number of artificial lunar glasses with compositions similar to lunar rocks 12009, 12012, 14305, 15021, and 15555. Zero porosity model-rock moduli are calculated for a number of lunar model-rocks, with mineralogies similar to Apollo 12, 14, and 16 rocks. Model-rock calculations indicate that rock types in the troctolitic composition range may provide reasonable modeling of the lunar upper mantle. Model calculations involving pore crack effects are compatible with a strong dependence of rock moduli on pore strain, and therefore of rock velocities on nonhydrostatic loading. The high velocity of rocks under uniaxial loading appears to be compatible with, and may aid in, interpretation of near-surface velocity profiles observed in the active seismic experiment.

Mercury porosimetry for comparing piece-wise hydraulic properties with full range pore characteristics of soil aggregates and porous rocks

NASA Astrophysics Data System (ADS)

Turturro, Antonietta Celeste; Caputo, Maria C.; Gerke, Horst H.

2017-04-01

Unsaturated hydraulic properties are essential in the modeling of water and solute movement in the vadose zone. Since standard hydraulic techniques are limited to specific moisture ranges, maybe affected by air entrapment, wettability problems, limitations due to water vapor pressure, and are depending on the initial saturation, the continuous maximal drying curves of the complete hydraulic functions can mostly not reflect the basic pore size distribution. The aim of this work was to compare the water retention curves of soil aggregates and porous rocks with their porosity characteristics. Soil aggregates of Haplic Luvisols from Loess L (Hneveceves, Czech Republic) and glacial Till T (Holzendorf, Germany) and two lithotypes of porous rock C (Canosa) and M (Massafra), Italy, were analyzed using, suction table, evaporation, psychrometry methods, and the adopted Quasi-Steady Centrifuge method for determination of unsaturated hydraulic conductivity. These various water-based techniques were applied to determine the piece-wise retention and the unsaturated hydraulic conductivity functions in the range of pore water saturations. The pore-size distribution was determined with the mercury intrusion porosimetry (MIP). MIP results allowed assessing the volumetric mercury content at applied pressures up to 420000 kPa. Greater intrusion and porosity values were found for the porous rocks than for the soil aggregates. Except for the aggregate samples from glacial till, maximum liquid contents were always smaller than porosity. Multimodal porosities and retention curves were observed for both porous rocks and aggregate soils. Two pore-size peaks with pore diameters of 0.135 and 27.5 µm, 1.847 and 19.7 µm, and 0.75 and 232 µm were found for C, M and T, respectively, while three peaks of 0.005, 0.392 and 222 µm were identified for L. The MIP data allowed describing the retention curve in the entire mercury saturation range as compared to water retention curves that required combining several methods for limited suction ranges. Although the soil aggregates and porous rocks differed in pore geometries and pore size distributions, MIP provided additional information for characterizing the relation between pore structure and hydraulic properties for both.

Stand up time in tunnel base on rock mass rating Bieniawski 1989

NASA Astrophysics Data System (ADS)

Nata, Refky Adi; M. S., Murad

2017-11-01

RMR (Rock Mass Rating), or also known as the geo mechanics classification has been modified and made as the International Standard in determination of rock mass weighting. Rock Mass Rating Classification has been developed by Bieniawski (since 1973, 1976, and 1989). The goals of this research are investigate the class of rocks base on classification rock mass rating Bieniawski 1989, to investigate the long mass of the establishment rocks, and also to investigate the distance of the opening tunnel without a support especially in underground mine. On the research measuring: strength intact rock material, RQD (Rock Quality Designation), spacing of discontinuities, condition of discontinuities, groundwater, and also adjustment for discontinuity orientations. On testing samples in the laboratory for coal obtained strong press UCS of 30.583 MPa. Based on the classification according to Bieniawski has a weight of 4. As for silt stone obtained strong press of 35.749 MPa, gained weight also by 4. From the results of the measurements obtained for coal RQD value average 97.38 %, so it has a weight of 20. While in siltstone RQD value average 90.10 % so it has weight 20 also. On the coal the average distance measured in field is 22.6 cm so as to obtain a weight of 10, while for siltstone has an average is 148 cm, so it has weight = 15. Presistence in the field vary, on coal = 57.28 cm, so it has weight is 6 and persistence on siltstone 47 cm then does it weight to 6. Base on table Rock Mass Rating according to Bieniawski 1989, aperture on coal = 0.41 mm. That is located in the range 0.1-1 mm, so it has weight is 4. Besides that, for the siltstone aperture = 21.43 mm. That is located in the range > 5 mm, so the weight = 0. Roughness condition in coal and siltstone classified into rough so it has weight 5. Infilling condition in coal and siltstone classified into none so it has weight 6. Weathering condition in coal and siltstone classified into highly weathered so it has weight 1. Groundwater condition in coal classified into dripping so it has weight 4. and siltstone classified into completely dry so it has weight 15. Discontinuity orientation in coal parallel axis of the tunnel. The range is 251°-290° so unfavorable. It has weight = -10. In siltstone also discontinuity parallel axis of the tunnel. The range located between 241°-300°. Base on weighting parameters according to Bieniawski 1989, concluded for rocks are there in class II with value is 62, and able to establishment until 6 months. For the distance of the opening tunnel without a support as far as 8 meters.

Short-Term Exposure to Warm Microhabitats Could Explain Amphibian Persistence with Batrachochytrium dendrobatidis

PubMed Central

Daskin, Joshua H.; Alford, Ross A.; Puschendorf, Robert

2011-01-01

Environmental conditions can alter the outcomes of symbiotic interactions. Many amphibian species have declined due to chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), but many others persist despite high Bd infection prevalence. This indicates that Bd's virulence is lower, or it may even be a commensal, in some hosts. In the Australian Wet Tropics, chytridiomycosis extirpated Litoria nannotis from high-elevation rain forests in the early 1990 s. Although the species is recolonizing many sites, no population has fully recovered. Litoria lorica disappeared from all known sites in the early 1990 s and was thought globally extinct, but a new population was discovered in 2008, in an upland dry forest habitat it shares with L. nannotis. All frogs of both species observed during three population censuses were apparently healthy, but most carried Bd. Frogs perch on sun-warmed rocks in dry forest streams, possibly keeping Bd infections below the lethal threshold attained in cooler rain forests. We tested whether short-term elevated temperatures can hamper Bd growth in vitro over one generation (four days). Simulating the temperatures available to frogs on strongly and moderately warmed rocks in dry forests, by incubating cultures at 33°C for one hour daily, reduced Bd growth below that of Bd held at 15°C constantly (representing rain forest habitats). Even small decreases in the exponential growth rate of Bd on hosts may contribute to the survival of frogs in dry forests. PMID:22028834

Short-term exposure to warm microhabitats could explain amphibian persistence with Batrachochytrium dendrobatidis.

PubMed

Daskin, Joshua H; Alford, Ross A; Puschendorf, Robert

2011-01-01

Environmental conditions can alter the outcomes of symbiotic interactions. Many amphibian species have declined due to chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), but many others persist despite high Bd infection prevalence. This indicates that Bd's virulence is lower, or it may even be a commensal, in some hosts. In the Australian Wet Tropics, chytridiomycosis extirpated Litoria nannotis from high-elevation rain forests in the early 1990 s. Although the species is recolonizing many sites, no population has fully recovered. Litoria lorica disappeared from all known sites in the early 1990 s and was thought globally extinct, but a new population was discovered in 2008, in an upland dry forest habitat it shares with L. nannotis. All frogs of both species observed during three population censuses were apparently healthy, but most carried Bd. Frogs perch on sun-warmed rocks in dry forest streams, possibly keeping Bd infections below the lethal threshold attained in cooler rain forests. We tested whether short-term elevated temperatures can hamper Bd growth in vitro over one generation (four days). Simulating the temperatures available to frogs on strongly and moderately warmed rocks in dry forests, by incubating cultures at 33°C for one hour daily, reduced Bd growth below that of Bd held at 15°C constantly (representing rain forest habitats). Even small decreases in the exponential growth rate of Bd on hosts may contribute to the survival of frogs in dry forests.

Mars Rock Analysis Briefing

NASA Image and Video Library

2013-03-12

Paul Mahaffy (right), principal investigator for Curiosity's Sample Analysis at Mars (SAM) investigation at NASA's Goddard Space Flight Center in Maryland, demonstrates how the SAM instrument drilled and captured rock samples on the surface of Mars at a news conference, Tuesday, March 12, 2013 at NASA Headquarters in Washington. The analysis of the rock sample collected shows ancient Mars could have supported living microbes. Photo Credit: (NASA/Carla Cioffi)

Isotopes and ages in the northern Peninsular Ranges batholith, southern California

USGS Publications Warehouse

Kistler, Ronald W.; Wooden, Joseph L.; Morton, Douglas M.

2003-01-01

Strontium, oxygen and lead isotopic and rubidium-strontium geochronologic studies have been completed on Cretaceous and Jurassic (?) granitic rock samples from the northern Peninsular Ranges batholith in southern California. Many of these samples were collected systematically and studied chemically by A. K. Baird and colleagues (Baird and others, 1979). The distribution of these granitic rocks is shown in the Santa Ana, Perris, and San Jacinto Blocks, bounded by the Malibu Coast-Cucamonga, Banning, and San Andreas fault zones, and the Pacific Ocean on the map of the Peninsular Ranges batholith and surrounding area, southern California. The granitic rock names are by Baird and Miesch (1984) who used a modal mineral classification that Bateman and others (1963) used for granitic rocks in the Sierra Nevada batholith. In this classification, granitic rocks have at least 10% quartz. Boundaries between rock types are in terms of the ratio of alkali-feldspar to total feldspar: quartz diorite, 0-10%; granodiorite, 10-35%; quartz monzonite 35-65%; granite >65%. Gabbros have 0-10% quartz. Data for samples investigated are giv in three tables: samples, longitude, latitude, specific gravity and rock type (Table 1); rubidium and strontium data for granitic rocks of the northern Peninsular Ranges batholith, southern California (Table 2); U, Th, Pb concentrations, Pb and Sr initial isotopic compositions, and δ18O permil values for granitic rocks of the northern Peninsular Ranges batholith (table 3).

Characterization of rock samples and mineralogical controls on leachates

USGS Publications Warehouse

Hammarstrom, Jane M.; Cravotta, Charles A.; Galeone, Daniel G.; Jackson, John C.; Dulong, Frank T.; Hornberger, Roger J.; Brady, Keith B.C.

2009-01-01

Rocks associated with coal beds typically include shale, sandstone, and (or) limestone. In addition to common rock-forming minerals, all of these rock types may contain sulfide and sulfate minerals, various carbonate minerals, and organic material. These different minerals have inherently different solubility characteristics, as well as different acid-generating or acid-neutralizing potentials. The abundance and composition of sulfur- and carbonate-bearing minerals are of particular interest in interpreting the leaching column data because (1) pyrite and carbonate minerals are the primary controls on the acid-base account of a sample, (2) these minerals incorporate trace metals that can be released during weathering, and (3) these minerals readily react during weathering due to mineral dissolution and oxidation of iron.Rock samples were collected by the Pennsylvania Department of Environmental Protection (PaDEP) from five different sites to assess the draft standardized leaching column method (ADTI-WP2) for the prediction of weathering rates and water quality at coal mines. Samples were sent to USGS laboratories for mineralogical characterization and to ActLabs for chemical analysis. The samples represent a variety of rock types (shales, sandstones, and coal refuse) that are typical of coal overburden in the eastern United States. These particular samples were chosen for testing the weathering protocols because they represent a range of geochemical and lithologic characteristics, sulfur contents, and acid-base accounting characteristics (Hornberger et al., 2003). The rocks contain variable amounts of pyrite and carbonate minerals and vary in texture.This chapter includes bulk rock chemical data and detailed mineralogical and textural data for unweathered starting materials used in the interlaboratory validation study, and for two samples used in the early phases of leaching column tests (Wadesville Sandstone, Leechburg Coal Refuse). We also characterize some of the post-weathering rock samples, report trace-element content in leachate, and discuss mineralogical controls on leachate quality based on data from one of the participating laboratories. Table 5.1 lists the samples described in this chapter, the sample numbers, and comments on the characteristics of each lithology. Sample locations are plotted in Figure 5.1. Chapters 2 and 3 describe the sample locations, sample preparation protocols, ABA characteristics, and rationale for selection of rock samples for testing. Microprobe data for pyrite and carbonate minerals are tabulated in Appendix 5.1. Leachate data, along with a series of graphs showing concentration and cumulative transport trends, for the laboratory data discussed in this chapter are included as Excel spreadsheets in Appendices 5.2 and 5.3. Leach column data for the interlaboratory study are evaluated and interpreted in Chapters 7 -11.

Permeameter studies of water flow through cement and clay borehole seals in granite, basalt and tuff

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

South, D.L.; Daemen, J.J.K.

1986-10-01

Boreholes near a repository must be sealed to prevent rapid migration of radionuclide-contaminated water to the accessible environment. The objective of this research is to assess the performance of borehole seals under laboratory conditions, particularly with regard to varying stress fields. Flow through a sealed borehole is compared with flow through intact rock. Cement or bentonite seals have been tested in granite, basalt, and welded tuff. The main conclusion is that under laboratory conditions, existing commercial materials can form high quality seals. Triaxial stress changes about a borehole do not significantly affect seal performance if the rock is stiffer thanmore » the seal. Temperature but especially moisture variations (drying) significantly degrade the quality of cement seals. Performance partially recovers upon resaturation. A skillfully sealed borehole may be as impermeable as the host rock. Analysis of the influence of relative seal-rock permeabilities shows that a plug with permeability one order of magnitude greater than that of the rock results in a flow increase through the hole and surrounding rock of only 1-1/2 times compared to the undisturbed rock. Since a borehole is only a small part of the total rock mass, the total effect is even less pronounced. The simplest and most effective way to decrease flow through a rock-seal system is to increase the seal length, assuming it can be guaranteed that no dominant by-pass flowpath through the rock exists.« less

Towards a delimitation of southwestern Nigeria into hydrological regions

NASA Astrophysics Data System (ADS)

Ogunkoya, O. O.

1988-05-01

Fifteen third-order drainage basins (1:50,000) on the Basement Complex rocks of southwestern Nigeria are classified into hydrological regions using hydrologic response parameters of average daily mean specific discharge ( QA); daily mean specific discharges equalled or exceeded 90% ( Q90), 50% ( Q50) and 10% ( Q10) of the study period; variability index of flow ( VI); recession constant ( K) of flow from peak discharge at the end of the rainy season to minimum discharge in the dry season; total annual runoff ( RO); total runoff within the dry season ( DSRO); dry season runoff as a percentage of total annual runoff (% DSRO); runoff coefficient ( ROC); and, number of days during the study period when there was no flow ( NFD). An ordination technique and a classification algorithm derived from cluster analysis technique and incorporating the analysis of variance (ANOVA) tests to determine the level of significance of the homogeneity of derived classes, were used to classify the fifteen basins into five hydrologically homogeneous regions. The constituent basins of each region were observed to share common basin geology. It was observed that those drainage basins having at least 50% of their basin area underlain by quartzitic rocks form two groups and have the most desirable or optimal hydrologic response patterns, desirability or optimality being in terms of ability to potentially meet water resource development requirements (i.e. high perennial discharge, low variability and large groundwater contribution to stream flow). The basins predominantly underlain by granite-gneisses and amphibolitic rocks have much poorer hydrologic response patterns. Hydrological regionalization in southwestern Nigeria appears to be influenced by drainage basin geology while percentage area of the basin underlain by massive quartzites could be used as an index of occurrence of desirable hydrologic response pattern.

Simulation of the evolution of root water foraging strategies in dry and shallow soils.

PubMed

Renton, Michael; Poot, Pieter

2014-09-01

The dynamic structural development of plants can be seen as a strategy for exploiting the limited resources available within their environment, and we would expect that evolution would lead to efficient strategies that reduce costs while maximizing resource acquisition. In particular, perennial species endemic to habitats with shallow soils in seasonally dry environments have been shown to have a specialized root system morphology that may enhance access to water resources in the underlying rock. This study aimed to explore these hypotheses by applying evolutionary algorithms to a functional-structural root growth model. A simulation model of a plant's root system was developed, which represents the dynamics of water uptake and structural growth. The model is simple enough for evolutionary optimization to be computationally feasible, yet flexible enough to allow a range of structural development strategies to be explored. The model was combined with an evolutionary algorithm in order to investigate a case study habitat with a highly heterogeneous distribution of resources, both spatially and temporally--the situation of perennial plants occurring on shallow soils in seasonally dry environments. Evolution was simulated under two contrasting fitness criteria: (1) the ability to find wet cracks in underlying rock, and (2) maximizing above-ground biomass. The novel approach successfully resulted in the evolution of more efficient structural development strategies for both fitness criteria. Different rooting strategies evolved when different criteria were applied, and each evolved strategy made ecological sense in terms of the corresponding fitness criterion. Evolution selected for root system morphologies which matched those of real species from corresponding habitats. Specialized root morphology with deeper rather than shallower lateral branching enhances access to water resources in underlying rock. More generally, the approach provides insights into both evolutionary processes and ecological costs and benefits of different plant growth strategies.

Reconnaissance studies of potential petroleum source rocks in the Middle Jurassic Tuxedni Group near Red Glacier, eastern slope of Iliamna Volcano

USGS Publications Warehouse

Stanley, Richard G.; Herriott, Trystan M.; LePain, David L.; Helmold, Kenneth P.; Peterson, C. Shaun

2013-01-01

Previous geological and organic geochemical studies have concluded that organic-rich marine shale in the Middle Jurassic Tuxedni Group is the principal source rock of oil and associated gas in Cook Inlet (Magoon and Anders, 1992; Magoon, 1994; Lillis and Stanley, 2011; LePain and others, 2012; LePain and others, submitted). During May 2009 helicopter-assisted field studies, 19 samples of dark-colored, fine-grained rocks were collected from exposures of the Red Glacier Formation of the Tuxedni Group near Red Glacier, about 70 km west of Ninilchik on the eastern flank of Iliamna Volcano (figs. 1 and 3). The rock samples were submitted to a commercial laboratory for analysis by Rock-Eval pyrolysis and to the U.S. Geological Survey organic geochemical laboratory in Denver, Colorado, for analysis of vitrinite reflectance. The results show that values of vitrinite reflectance (percent Ro) in our samples average about 2 percent, much higher than the oil window range of 0.6–1.3 percent (Johnsson and others, 1993). The high vitrinite reflectance values indicate that the rock samples experienced significant heating and furthermore suggest that these rocks may have generated oil and gas in the past but no longer have any hydrocarbon source potential. The high thermal maturity of the rock samples may have resulted from (1) the thermaleffects of igneous activity (including intrusion by igneous rocks), (2) deep burial beneath Jurassic, Cretaceous, and Tertiary strata that were subsequently removed by uplift and erosion, or (3) the combined effects of igneous activity and burial.

Comparing slow and fast rupture in laboratory experiments

NASA Astrophysics Data System (ADS)

Aben, F. M.; Brantut, N.; David, E.; Mitchell, T. M.

2017-12-01

During the brittle failure of rock, elastically stored energy is converted into a localized fracture plane and surrounding fracture damage, seismic radiation, and thermal energy. However, the partitioning of energy might vary with the rate of elastic energy release during failure. Here, we present the results of controlled (slow) and dynamic (fast) rupture experiments on dry Lanhélin granite and Westerly granite samples, performed under triaxial stress conditions at confining pressures of 50 and 100 MPa. During the tests, we measured sample shortening, axial load and local strains (with 2 pairs of strain gauges glued directly onto the sample). In addition, acoustic emissions (AEs) and changes in seismic velocities were monitored. The AE rate was used as an indicator to manually control the axial load on the sample to stabilize rupture in the quasi-static failure experiments. For the dynamic rupture experiments a constant strain rate of 10-5 s-1 was applied until sample failure. A third experiment, labeled semi-controlled rupture, involved controlled rupture up to a point where the rupture became unstable and the remaining elastic energy was released dynamically. All experiments were concluded after a macroscopic fracture had developed across the whole sample and frictional sliding commenced. Post-mortem samples were epoxied, cut and polished to reveal the macroscopic fracture and the surrounding damage zone. The samples failed with average rupture velocities varying from 5x10-6 m/s up to >> 0.1 m/s. The analyses of AE locations on the slow ruptures reveal that within Westerly granite samples - with a smaller grain size - fracture planes are disbanded in favor of other planes when a geometrical irregularity is encountered. For the coarser grained Lanhélin granite a single fracture plane is always formed, although irregularities are recognized as well. The semi-controlled experiments show that for both rock types the rupture can become unstable in response to these irregularities. In Westerly granite, slow rupture experiments tend to produce complex fracture patterns while during the dynamic rupture experiments secondary rupture planes are not formed. These findings show that grain or flaw size, flaw distribution, and rupture speed strongly influence fracture localization and propagation.

Advancing microwave technology for dehydration processing of biologics.

PubMed

Cellemme, Stephanie L; Van Vorst, Matthew; Paramore, Elisha; Elliott, Gloria D

2013-10-01

Our prior work has shown that microwave processing can be effective as a method for dehydrating cell-based suspensions in preparation for anhydrous storage, yielding homogenous samples with predictable and reproducible drying times. In the current work an optimized microwave-based drying process was developed that expands upon this previous proof-of-concept. Utilization of a commercial microwave (CEM SAM 255, Matthews, NC) enabled continuous drying at variable low power settings. A new turntable was manufactured from Ultra High Molecular Weight Polyethylene (UHMW-PE; Grainger, Lake Forest, IL) to provide for drying of up to 12 samples at a time. The new process enabled rapid and simultaneous drying of multiple samples in containment devices suitable for long-term storage and aseptic rehydration of the sample. To determine sample repeatability and consistency of drying within the microwave cavity, a concentration series of aqueous trehalose solutions were dried for specific intervals and water content assessed using Karl Fischer Titration at the end of each processing period. Samples were dried on Whatman S-14 conjugate release filters (Whatman, Maidestone, UK), a glass fiber membrane used currently in clinical laboratories. The filters were cut to size for use in a 13 mm Swinnex(®) syringe filter holder (Millipore(™), Billerica, MA). Samples of 40 μL volume could be dehydrated to the equilibrium moisture content by continuous processing at 20% with excellent sample-to-sample repeatability. The microwave-assisted procedure enabled high throughput, repeatable drying of multiple samples, in a manner easily adaptable for drying a wide array of biological samples. Depending on the tolerance for sample heating, the drying time can be altered by changing the power level of the microwave unit.

Hydrochemical and environmental isotope analysis of groundwater and surface water in a dry mountain region in Northern Chile.

PubMed

Zang, Carina; Dame, Juliane; Nüsser, Marcus

2018-05-08

This case study examines the geological imprint and land use practices on water quality in the arid Huasco Valley against the backdrop of ongoing water conflicts surrounding competing demands for agriculture and mining. The study is based on a detailed analysis of spatial and temporal variations of monthly surface and bi-monthly groundwater quality samples measured during the Chilean summer of 2015/16. Additional information on source regions and river-groundwater interactions were collected using stable water isotopes. Regarding the geological impact on water quality, high concentrations of Ca 2+ , SO 4 2- and HCO 3 - indicate a strong influence of magmatic rocks, which constitute this high mountain basin, on the hydrochemistry. Piper and Gibbs-diagrams revealed that all samples show a homogenous distribution dominated by rock-water interactions. Measured NO 3 - concentrations in surface water are generally low. However, groundwater aquifers exhibit higher concentrations. Mn is the only heavy metal with elevated concentrations in surface water, which are possibly related to mining activities. The results illustrate that both surface and groundwater can be classified as suitable for irrigation. In addition, groundwater has been found to be suitable as drinking water. High similarities in isotopic signatures indicate a strong connection between surface and groundwater. Isotopic analyses suggest a strong influence of evaporation. This combined approach of hydrogeochemical and isotopic analysis proved to be a helpful tool in characterizing the catchment and can serve as a basis for future sustainable water management.

Freeze-Drying as Sample Preparation for Micellar Electrokinetic Capillary Chromatography – Electrochemical Separations of Neurochemicals in Drosophila Brains

PubMed Central

Berglund, E. Carina; Kuklinski, Nicholas J.; Karagündüz, Ekin; Ucar, Kubra; Hanrieder, Jörg; Ewing, Andrew G.

2013-01-01

Micellar electrokinetic capillary chromatography with electrochemical detection has been used to quantify biogenic amines in freeze-dried Drosophila melanogaster brains. Freeze drying samples offers a way to preserve the biological sample while making dissection of these tiny samples easier and faster. Fly samples were extracted in cold acetone and dried in a rotary evaporator. Extraction and drying times were optimized in order to avoid contamination by red-pigment from the fly eyes and still have intact brain structures. Single freeze-dried fly-brain samples were found to produce representative electropherograms as a single hand-dissected brain sample. Utilizing the faster dissection time that freeze drying affords, the number of brains in a fixed homogenate volume can be increased to concentrate the sample. Thus, concentrated brain samples containing five or fifteen preserved brains were analyzed for their neurotransmitter content, and five analytes; dopamine N-acetyloctopamine, Nacetylserotonin, N-acetyltyramine, N-acetyldopamine were found to correspond well with previously reported values. PMID:23387977

Preparing rock powder specimens of controlled size distribution

NASA Technical Reports Server (NTRS)

Blum, P.

1968-01-01

Apparatus produces rock powder specimens of the size distribution needed in geological sampling. By cutting grooves in the surface of the rock sample and then by milling these shallow, parallel ridges, the powder specimen is produced. Particle size distribution is controlled by changing the height and width of ridges.

Net Acid Production, Acid Neutralizing Capacity, and Associated Mineralogical and Geochemical Characteristics of Animas River Watershed Igneous Rocks Near Silverton, Colorado

USGS Publications Warehouse

Yager, Douglas B.; Choate, LaDonna; Stanton, Mark R.

2008-01-01

This report presents results from laboratory and field studies involving the net acid production (NAP), acid neutralizing capacity (ANC), and magnetic mineralogy of 27 samples collected in altered volcanic terrain in the upper Animas River watershed near Silverton, Colo., during the summer of 2005. Sampling focused mainly on the volumetrically important, Tertiary-age volcanic and plutonic rocks that host base- and precious-metal mineralization in the study area. These rocks were analyzed to determine their potential for neutralization of acid-rock drainage. Rocks in the study area have been subjected to a regional propylitic alteration event, which introduced calcite, chlorite (clinochlore), and epidote that have varying amounts and rates of acid neutralizing capacity (ANC). Locally, hydrothermal alteration has consumed any ANC and introduced minerals, mainly pyrite, that have a high net acid production (NAP). Laboratory studies included hydrogen pyroxide (H2O2) acid digestion and subsequent sodium hydroxide (NaOH) titration to determine NAP, and sulfuric acid (H2SO4) acid titration experiments to determine ANC. In addition to these environmental rock-property determinations, mineralogical, chemical, and petrographic characteristics of each sample were determined through semiquantitative X-ray diffractometry (Rietveld method), optical mineralogy, wavelength dispersive X-ray fluorescence, total carbon-carbonate, and inductively coupled plasma?mass spectrometric analysis. An ANC ranking was assigned to rock samples based on calculated ANC quantity in kilograms/ton (kg/t) calcium carbonate equivalent and ratios of ANC to NAP. Results show that talus near the southeast Silverton caldera margin, composed of andesite clasts of the Burns Member of the Silverton Volcanics, has the highest ANC (>100 kg/t calcium carbonate equivalent) with little to no NAP. The other units found to have moderate to high ANC include (a) andesite lavas and volcaniclastic rocks of the San Juan Formation, west and northwest of the Silverton caldera, and (b) the Picayune Megabreccia Member of Sapinero Mesa Tuff along the western San Juan caldera margin. Sultan Mountain stock, composed of granitoid intrusive rocks, was shown to have low ANC and moderate NAP. Sequential leachate analyses on a suite of whole-rock samples from the current and a previous study indicate that host rock composition and mineralogy control leachate compositions. The most mafic volcanic samples had high leachate concentrations for Mg, Fe, and Ca, whereas silicic volcanic samples had lower ferromagnesiun compositions. Samples with high chlorite abundance also had high leachable Mg concentrations. Trace-element substitution, such as Sr for Ca in plagioclase, controls high Sr concentrations in those samples with high plagioclase abundance. High Ti abundance in leachate was observed in those samples with high magnetite concentrations. This is likely due to samples containing intergrown magnetite-ilmenite. Whole rocks having high trace-element concentrations have relatively high leachate trace-element abundances. Some lavas of the San Juan Formation and Burns Member of the Silverton Volcanics had elevated Zn-, Cd-, and Pb-leachate concentrations. Manganese was also elevated in one San Juan Formation sample. Other San Juan Formation and Burns Member lavas had low to moderate trace-element abundances. One sample of the pyroxene andesite member of the Silverton Volcanics had elevated concentrations for As and Mo. Most other pyroxene andesite member samples had low leachate trace-element abundances. Mine-waste-leachate analyses indicated that one mine-waste sample had elevated concentrations of Cu (1.5 orders of magnitude), Zn (1 order of magnitude), As (1 order of magnitude), Mo (1.5 to 2 orders of magnitude), Cd (1 to 2 orders of magnitude), and Pb (2 to 3 orders of magnitude) compared to whole rocks. These data indicate the importance of whole-rock geochemistry or leachate analys

Apollo Lunar Sample Integration into Google Moon: A New Approach to Digitization

NASA Technical Reports Server (NTRS)

Dawson, Melissa D.; Todd, nancy S.; Lofgren, Gary E.

2011-01-01

The Google Moon Apollo Lunar Sample Data Integration project is part of a larger, LASER-funded 4-year lunar rock photo restoration project by NASA s Acquisition and Curation Office [1]. The objective of this project is to enhance the Apollo mission data already available on Google Moon with information about the lunar samples collected during the Apollo missions. To this end, we have combined rock sample data from various sources, including Curation databases, mission documentation and lunar sample catalogs, with newly available digital photography of rock samples to create a user-friendly, interactive tool for learning about the Apollo Moon samples

Natural radionuclides in the rocks of the Valle del Cervo Pluton in Piedmont.

PubMed

Sesana, Lucia; Fumagalli, Marco; Carnevale, Mauro; Polla, Giancarla; Facchini, Ugo; Colombo, Annita; Tunesi, Annalisa; De Capitani, Luisa; Rusconi, Rosella

2006-01-01

Monitoring of the gamma radiation in Valle del Cervo Pluton was performed by determining U and Th contents in the main rock types cropping out over the entire area and pertaining to the granitic complex, syenitic complex and monzonitic complex. In particular, syenitic rocks were largely used as building and ornamental materials (e.g. Sienite della Balma). All the samples are fresh and do not present joints or fractures filled with U minerals. In the crushed samples the activity of uranium varies from 346 to 764 Bq/kg. Concentration of thorium varies from 202 to 478 Bq/kg. For all the analysed rocks uranium activity is higher than thorium one. The lowest value of radioactive concentration is referred to rocks of the granitic complex. The most active rocks are syenites. The data confirm the high activities of Valle del Cervo rock types, strongly connected with high K content of the source magma (geochemical signature); on the contrary, the activity seems to be not related to the location of the samples.

Rock sample brought to earth from the Apollo 12 lunar landing mission

NASA Technical Reports Server (NTRS)

1969-01-01

Close-up view of Apollo 12 sample 12,052 under observation in the Manned Spacecraft Center's Lunar Receiving Laboratory. This sample, collected during the second Apollo 12 extravehicular activity (EVA-2) of Astronauts Charles Conrad Jr., and Alan L. Bean, is a typical fine-grained crystalline rock with a concentration of holes on the left part of the exposed side. These holes are called vesicles and have been labeled as gas bubbles formed during the crystallization of the rock. Several glass-lined pits can be seen on the surface of the rock. An idea of the size of the rock can be gained by reference to the gauge on the bottom portion of the number meter.

Hot Dry Rock Geothermal Energy Development Program: Annual report, fiscal year 1985

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

Brown, D.W.; Franke, P.R.; Smith, M.C.

1987-01-01

The primary objective for the Hot Dry Rock Program at the Los Alamos National Laboratory during fiscal year 1985 was to complete the Phase 2 reservoir connection and to begin flow testing the resulting reservoir. The connection was achieved through redrilling one well and additional fracturing operations, and progress was made toward developing a detailed understanding of the fractured region through a variety of reservoir interrogation methods. Other accomplishments during the fiscal year included improvement of the high-temperature, inflatable, open-hole packer used to isolate sections of the uncased wellbore in collaboration with the Baker Corporation and the design and fabricationmore » of a high-temperature borehole acoustic televiewer in a cooperative program with a research institute in West Germany. Progress was also made in techniques for the collection and analysis of microseismic data. Reservoir-engineering activities and geochemical studies, as well as the more routine support activities, continued in FY85. 18 refs., 15 figs.« less

Hot Dry Rock Geothermal Energy Development Program. Annual report, fiscal year 1979

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

Cremer, G.M.; Duffield, R.B.; Smith, M.C.

1980-08-01

The Fenton Hill Project is still the principal center for developing methods, equipment, and instrumentation for creating and utilizing HDR geothermal reservoirs. The search for a second site for a similar experimental system in a different geological environment has been intensified, as have the identification and characterization of other HDR areas that may prove suitable for either experimental or commercial development. The Phase I fracture system was enlarged during FY79. Drilling of the injection well of the Phase II system began at Fenton Hill in April 1979. Environmental monitoring of the Fenton Hill area continued through FY79. The environmental studiesmore » indicate that the hot dry rock operations have caused no significant environmental impact. Other supporting activities included rock physics, rock mechanics, fracture mapping, and instrumentation development. Two closely related activities - evaluation of the potential HDR energy resource of the US and the selection of a site for development of a second experimental heat-extraction system generally similar to that at Fenton Hill - have resulted in the collection of geology, hydrology, and heat-flow data on some level of field activity in 30 states. The resource-evaluation activity included reconnaissance field studies and a listing and preliminary characterization of US geothermal areas in which HDR energy extraction methods may be applicable. The selection of Site 2 has taken into account such legal, institutional, and economic factors as land ownership and use, proximity to possible users, permitting and licensing requirements and procedures, environmental issues, areal extent of the geothermal area, and visibility to and apparent interest by potential industrial developers.« less

Erosion Rates at the Mars Exploration Rover Landing Sites and Long-Term Climate Change on Mars

NASA Technical Reports Server (NTRS)

Golombek, M. P.; Grant, J. A.; Crumpler, L. S.; Greeley, R.; Arvidson, R. E.; Bell, J. F., III; Weitz, C. M.; Sullivan, R.; Christensen, P. R.; Soderblom, L. A.;

Erosion rates at the Mars Exploration Rover landing sites and long-term climate change on Mars

USGS Publications Warehouse

Golombek, M.P.; Grant, J. A.; Crumpler, L.S.; Greeley, R.; Arvidson, R. E.; Bell, J.F.; Weitz, C.M.; Sullivan, R.J.; Christensen, P.R.; Soderblom, L.A.; Squyres, S. W.

2006-01-01

Erosion rates derived from the Gusev cratered plains and the erosion of weak sulfates by saltating sand at Meridiani Planum are so slow that they argue that the present dry and desiccating environment has persisted since the Early Hesperian. In contrast, sedimentary rocks at Meridiani formed in the presence of groundwater and occasional surface water, and many Columbia Hills rocks at Gusev underwent aqueous alteration during the Late Noachian, approximately coeval with a wide variety of geomorphic indicators that indicate a wetter and likely warmer environment. Two-toned rocks, elevated ventifacts, and perched and undercut rocks indicate localized deflation of the Gusev plains and deposition of an equivalent amount of sediment into craters to form hollows, suggesting average erosion rates of ???0.03 nm/yr. Erosion of Hesperian craters, modification of Late Amazonian craters, and the concentration of hematite concretions in the soils of Meridiani yield slightly higher average erosion rates of 1-10 nm/yr in the Amazonian. These erosion rates are 2-5 orders of magnitude lower than the slowest continental denudation rates on Earth, indicating that liquid water was not an active erosional agent. Erosion rates for Meridiani just before deposition of the sulfate-rich sediments and other eroded Noachian areas are comparable with slow denudation rates on Earth that are dominated by liquid water. Available data suggest the climate change at the landing sites from wet and likely warm to dry and desiccating occurred sometime between the Late Noachian and the beginning of the Late Hesperian (3.7-3.5 Ga). Copyright 2006 by the American Geophysical Union.

Consumer sensory acceptance and value of wet-aged and dry-aged beef steaks.

PubMed

Sitz, B M; Calkins, C R; Feuz, D M; Umberger, W J; Eskridge, K M

2006-05-01

To determine sensory preference and value of fresh beef steak differing in aging technique, strip steaks were evaluated by consumers in Denver (n = 132 consumers) and Chicago (n = 141 consumers). Wet-aged Choice strip loins were matched with dry-aged Choice strip loins, whereas wet-aged Prime strip loins were matched with dry-aged Prime strip loins. Dry-aged strip loins were commercially aged in air in a controlled environment for 30 d and vacuum-aged for 7 d during shipping and storage. Wet-aged strip loins were vacuum-packaged and aged for 37 d in a 1 degrees C cooler. Pairs of strip loins were matched to similar Warner-Bratzler shear force values and marbling scores. Twelve sensory evaluation panels (of 12 scheduled panelists each) were conducted over a 3-d period in each city. Individual samples from a pair of steaks were evaluated by the panelists for sensory traits. Bids were placed on the samples after sensory traits were obtained utilizing a variation of the Vickery auction with silent, sealed bids. No significant differences for sensory traits of flavor, juiciness, tenderness, or overall acceptability were detected between wet-aged Choice samples and dry-aged Choice samples. Although wet-aged Choice samples were numerically superior for all sensory traits, consumers placed similar bid values (P = 0.12) on wet- and dry-aged Choice samples ($3.82 per 0.45 kg and $3.57 per 0.45 kg, respectively). Wet-aged Prime samples were rated more desirable (P < 0.001) for flavor, tenderness, and overall acceptability than dry-aged Prime samples. Wet-aged Prime samples were valued at $4.02 per 0.45 kg, whereas dry-aged Prime samples brought $3.58 per 0.45 kg (P = 0.008). Consumers (29.3%) who preferred the dry-aged Choice samples over the wet-aged Choice samples were willing to pay $1.99/0.45 kg more (P < 0.001) for dry-aged samples. The consumers who preferred the wet-aged Choice over the dry-aged Choice samples (39.2%) were willing to pay $1.77/0.45 kg more (P < 0.0001). Consumers who preferred wet-aged Prime over dry-aged Prime samples (45.8%) paid $1.92/0.45 kg more (P < 0.0001). Consumers who preferred dry-aged Prime samples (27.5%) were willing to pay $1.92/0.45 kg more than for the wet-aged Prime samples. Although more consumers preferred wet-aged samples, markets do exist for dry-aged beef, and consumers are willing to pay a premium for this product.

Maps showing abundance and distribution of mercury in rock samples, Medford 1 degree by 2 degrees Quadrangle, Oregon-California

USGS Publications Warehouse

Whittington, Charles L.; Grimes, David J.; Leinz, Reinhard W.

1985-01-01

This map presents data on the abundance and distribution of mercury in 3,146 rock samples from the Medford quadrangle. Most of the rock samples were collected incidental to geologic, geochemical, and mineral resources studies in the period from 1974 to 1980, but about 6 percent date from earlier investigations (Wells, 1940; 1956; Wells and others 1949). 

Cryo-conditioned rocky coast systems: A case study from Wilczekodden, Svalbard.

PubMed

Strzelecki, M C; Kasprzak, M; Lim, M; Swirad, Z M; Jaskólski, M; Pawłowski, Ł; Modzel, P

2017-12-31

This paper presents the results of an investigation into the processes controlling development of a cryo-conditioned rock coast system in Hornsund, Svalbard. A suite of nested geomorphological and geophysical methods have been applied to characterise the functioning of rock cliffs and shore platforms influenced by lithological control and geomorphic processes driven by polar coast environments. Electrical resistivity tomography (ERT) surveys have been used to investigate permafrost control on rock coast dynamics and reveal the strong interaction with marine processes in High Arctic coastal settings. Schmidt hammer rock tests, demonstrated strong spatial control on the degree of rock weathering (rock strength) along High Arctic rock coasts. Elevation controlled geomorphic zones are identified and linked to distinct processes and mechanisms, transitioning from peak hardness values at the ice foot through the wave and storm dominated scour zones to the lowest values on the cliff tops, where the effects of periglacial weathering dominate. Observations of rock surface change using a traversing micro-erosion meter (TMEM) indicate that significant changes in erosion rates occur at the junction between the shore platform and the cliff toe, where rock erosion is facilitated by frequent wetting and drying and operation of nivation and sea ice processes (formation and melting of snow patches and icefoot complexes). The results are synthesised to propose a new conceptual model of High Arctic rock coast systems, with the aim of contributing towards a unifying concept of cold region landscape evolution and providing direction for future research regarding the state of polar rock coasts. Copyright © 2017 Elsevier B.V. All rights reserved.

Anomalously low strength of serpentinite sheared against granite and implications for creep on the Hayward and Calaveras Faults

USGS Publications Warehouse

Moore, Diane E.; Lockner, David A.; Ponce, David A.

2010-01-01

Serpentinized ophiolitic rocks are juxtaposed against quartzofeldspathic rocks at depth across considerable portions of the Hayward and Calaveras Faults. The marked compositional contrast between these rock types may contribute to fault creep that has been observed along these faults. To investigate this possibility, we are conducting hydrothermal shearing experiments to look for changes in frictional properties resulting from the shear of ultramafic rock juxtaposed against quartzose rock units. In this paper we report the first results in this effort: shear of bare-rock surfaces of serpentinite and granite, and shear of antigorite-serpentinite gouge between forcing blocks of granitic rock. All experiments were conducted at 250°C. Serpentinite sheared against granite at 50 MPa pore-fluid pressure is weaker than either rock type separately, and the weakening is significantly more pronounced at lower shearing rates. In contrast, serpentinite gouge sheared dry between granite blocks is as strong as the bare granite surface. We propose that the weakening is the result of a solution-transfer process involving the dissolution of serpentine minerals at grain-to-grain contacts. Dissolution of serpentine is enhanced by modifications to pore-fluid chemistry caused by interaction of the fluid with the quartz-bearing rocks. The compositional differences between serpentinized ultramafic rocks of the Coast Range Ophiolite and quartzofeldspathic rock units such as those of the Franciscan Complex may provide the mechanism for aseismic slip (creep) in the shallow crust along the Hayward, Calaveras, and other creeping faults in central and northern California.

A new method for automatic discontinuity traces sampling on rock mass 3D model

NASA Astrophysics Data System (ADS)

Umili, G.; Ferrero, A.; Einstein, H. H.

2013-02-01

A new automatic method for discontinuity traces mapping and sampling on a rock mass digital model is described in this work. The implemented procedure allows one to automatically identify discontinuity traces on a Digital Surface Model: traces are detected directly as surface breaklines, by means of maximum and minimum principal curvature values of the vertices that constitute the model surface. Color influence and user errors, that usually characterize the trace mapping on images, are eliminated. Also trace sampling procedures based on circular windows and circular scanlines have been implemented: they are used to infer trace data and to calculate values of mean trace length, expected discontinuity diameter and intensity of rock discontinuities. The method is tested on a case study: results obtained applying the automatic procedure on the DSM of a rock face are compared to those obtained performing a manual sampling on the orthophotograph of the same rock face.

Effect of crustal heterogeneities and effective rock strength on the formation of HP and UHP rocks.

NASA Astrophysics Data System (ADS)

Reuber, Georg; Kaus, Boris; Schmalholz, Stefan; White, Richard

2015-04-01

The formation of high pressure and ultra-high pressure rocks has been controversially discussed in recent years. Most existing petrological interpretations assume that pressure in the Earth is lithostatic and therefore HP and UHP rocks have to come from great depth, which usually involves going down a subduction channel and being exhumed again. Yet, an alternative explanation points out that pressure in the lithosphere is often non-lithostatic and can be either smaller or larger than lithostatic as a function of location and time. Whether this effect is tectonically significant or not depends on the magnitude of non-lithostatic pressure, and as a result a number of researchers have recently performed numerical simulations to address this. Somewhat disturbingly, they obtained widely differing results with some claiming that overpressures as large as a GPa can occur (Schmalholz et al. 2014), whereas others show that overpressures of exhumed rocks are generally less than 20% and thus insignificant (Li et al. 2010; Burov et al. 2014). In order to understand where these discrepancies come from, we reproduce the simulations of Li et al (2010) of a typical subduction and collision scenario, using an independently developed numerical code (MVEP2). For the same model setup and parameters, we confirm the earlier results of Li et al. (2010) and obtain no more than ~20% overpressure in exhumed rocks of the subduction channel. Yet, a critical assumption in their models is that the subducted crust is laterally homogeneous and that it has a low effective friction angle that is less than 7o. The friction angle of (dry) rocks is experimentally well-constrained to be around 30o, and low effective friction angles require, for example, high-fluid pressures. Whereas high fluid pressures might exist in the sediment-rich upper crust, they are likely to be much lower or absent in the lower crust from which melt has been extracted or in rocks that underwent a previous orogenic cycle. In a next step, we performed several hundred numerical simulations to understand the effects of km-scale heterogeneities and material parameters on pressure magnitudes, using a model setup that is otherwise very similar to the one of Li et al. (2010). Results show that significant non-lithostatic pressures occur if (lower) crustal rocks are dry or if km-scale (nappe-sized) heterogeneities with dryer rocks are present within the crust. Overpressure magnitudes can be up to 1 GPa or 100% and in some cases rock assemblages are temporarily in the coesite stability field at a depth of only 40 km, followed by rapid exhumation to the surface. Tectonic overpressures can vary strongly in magnitude versus time, but peak pressures are present sufficiently long for metamorphic reactions to occur. The presence of heterogeneities can affect the crustal-scaled deformation pattern, and the effective friction angle of crustal-scale rocks (or the dryness of these rocks) is a key parameter that determines the magnitude of non-lithostatic pressures. Our results thus reconcile previous findings and highlight the importance of having an accurate knowledge of the fluid-pressure, initial crustal structure and rock composition during continental collision. If rocks are dry by the time they enter a subduction zone, or are stronger/dryer than surrounding rocks, they are likely to develop significantly higher pressures than nearby rocks. This might explain the puzzling observation that some nappes have very high peak pressures, while juxtaposed nappes have much lower values, without clear structural evidence for deep burial and exhumation along a subduction channel of the high-pressure nappe. Our models might also give a partial explanation of why the reported timescales for high and ultra-high pressure stages of peak metamorphism are often very short. References: Burov, E., Francois, T., Agard, P., Le Pourhiet, L., Meyer, B., Tirel, C., Lebedev, S., Yamato, P., Brun, J.-P., 2014. Tectonophysics. Tectonophysics 631, 212-250. doi:10.1016/j.tecto.2014.04.033 Li, Z.H., Gerya, T.V., Burg, J.-P., 2010. Influence of tectonic overpressure on P-T paths of HP-UHP rocks in continental collision zones: thermomechanical modelling. J Metamorph Geol 28, 227-247. doi:10.1111/j.1525-1314.2009.00864.x Schmalholz, S.M., Duretz, T., Schenker, F.L., Podladchikov, Y.Y., 2014. Tectonophysics. Tectonophysics 631, 160-175. doi:10.1016/j.tecto.2014.05.018

Detrital zircon analysis of Mesoproterozoic and neoproterozoic metasedimentary rocks of northcentral idaho: Implications for development of the Belt-Purcell basin

USGS Publications Warehouse

Lewis, R.S.; Vervoort, J.D.; Burmester, R.F.; Oswald, P.J.

2010-01-01

The authors analyzed detrital zircon grains from 10 metasedimentary rock samples of the Priest River complex and three other amphibolite-facies metamorphic sequences in north-central Idaho to test the previous assignment of these rocks to the Mesoproterozoic Belt-Purcell Supergroup. Zircon grains from two samples of the Prichard Formation (lower Belt) and one sample of Cambrian quartzite were also analyzed as controls with known depositional ages. U-Pb zircon analysis by laser ablation - inductively coupled plasma - mass spectrometry reveals that 6 of the 10 samples contain multiple age populations between 1900 and 1400 Ma and a scatter of older ages, similar to results reported from the Belt- Purcell Supergroup to the north and east. Results from the Priest River metamorphic complex confirm previous correlations with the Prichard Formation. Samples from the Golden and Elk City sequences have significant numbers of 1500-1380 Ma grains, which indicates that they do not predate the Belt. Rather, they are probably from a relatively young, southwestern part of the Belt Supergroup (Lemhi subbasin). Non-North American (1610-1490 Ma) grains are rare in these rocks. Three samples of quartzite from the Syringa metamorphic sequence northwest of the Idaho batholith contain zircon grains younger than the Belt Supergroup and support a Neoproterozoic age. A single Cambrian sample has abundant 1780 Ma grains and none younger than ~1750 Ma. These results indicate that the likely protoliths of many high-grade metamorphic rocks in northern Idaho were strata of the Belt-Purcell Supergroup or overlying rocks of the Neoproterozoic Windermere Supergroup and not basement rocks.

Source rock potential of middle cretaceous rocks in Southwestern Montana

USGS Publications Warehouse

Dyman, T.S.; Palacas, J.G.; Tysdal, R.G.; Perry, W.J.; Pawlewicz, M.J.

1996-01-01

The middle Cretaceous in southwestern Montana is composed of a marine and nonmarine succession of predominantly clastic rocks that were deposited along the western margin of the Western Interior Seaway. In places, middle Cretaceous rocks contain appreciable total organic carbon (TOC), such as 5.59% for the Mowry Shale and 8.11% for the Frontier Formation in the Madison Range. Most samples, however, exhibit less than 1.0% TOC. The genetic or hydrocarbon potential (S1+S2) of all the samples analyzed, except one, yield less than 1 mg HC/g rock, strongly indicating poor potential for generating commercial amounts of hydrocarbons. Out of 51 samples analyzed, only one (a Thermopolis Shale sample from the Snowcrest Range) showed a moderate petroleum potential of 3.1 mg HC/g rock. Most of the middle Cretaceous samples are thermally immature to marginally mature, with vitrinite reflectance ranging from about 0.4 to 0.6% Ro. Maturity is high in the Pioneer Mountains, where vitrinite reflectance averages 3.4% Ro, and at Big Sky Montana, where vitrinite reflectance averages 2.5% Ro. At both localities, high Ro values are due to local heat sources, such as the Pioneer batholith in the Pioneer Mountains.

Hydrogeophysical investigation of Logan, MT using electrical techniques and diving wave refraction tomography

NASA Astrophysics Data System (ADS)

Stipe, T. D.

2014-12-01

Logan, Montana USA is located on the Gallatin river, one of the three rivers forming the headwaters of the Missouri river. Hydrogeological studies by the Montana Bureau of Mines and Geology have assumed that the location at Logan is a pinch-point for the local Gallatin watershed. Shallow groundwater is expected to discharge into the Gallatin river because depth to bedrock near the river is shallow (~5 meters). Groundwater monitoring wells indicate dry Tertiary sediments overlying bedrock, suggesting surface and groundwater systems are disconnected. We deployed shallow seismic refraction, electrical resistivity, spontaneous potential, and electromagnetic surveys to investigate the groundwater system in the study area. Geophysical measurements were preferentially obtained near the Gallatin river and close to shallow monitoring wells. Hand samples of Mississippian aged rocks of the Madison group were collected from local outcrops to help correlate geophysical results with properties of the carbonate rich bedrock. Preliminary interpretations of geophysical data confirm the shallow bedrock and dry sediments encountered in nearby wells. These results suggest that the pinch-point is located upstream or groundwater follows a network of preferential flow paths through limestone bedrock within the study area.

Characterization of rock thermal conductivity by high-resolution optical scanning

USGS Publications Warehouse

Popov, Y.A.; Pribnow, D.F.C.; Sass, J.H.; Williams, C.F.; Burkhardt, H.

1999-01-01

We compared thress laboratory methods for thermal conductivity measurements: divided-bar, line-source and optical scanning. These methods are widely used in geothermal and petrophysical studies, particularly as applied to research on cores from deep scientific boreholes. The relatively new optical scanning method has recently been perfected and applied to geophysical problems. A comparison among these methods for determining the thermal conductivity tensor for anisotropic rocks is based on a representative collection of 80 crystalline rock samples from the KTB continental deep borehole (Germany). Despite substantial thermal inhomogeneity of rock thermal conductivity (up to 40-50% variation) and high anisotropy (with ratios of principal values attaining 2 and more), the results of measurements agree very well among the different methods. The discrepancy for measurements along the foliation is negligible (<1%). The component of thermal conductivity normal to the foliation reveals somewhat larger differences (3-4%). Optical scanning allowed us to characterize the thermal inhomogeneity of rocks and to identify a three-dimensional anisotropy in thermal conductivity of some gneiss samples. The merits of optical scanning include minor random errors (1.6%), the ability to record the variation of thermal conductivity along the sample, the ability to sample deeply using a slow scanning rate, freedom from constraints for sample size and shape, and quality of mechanical treatment of the sample surface, a contactless mode of measurement, high speed of operation, and the ability to measure on a cylindrical sample surface. More traditional methods remain superior for characterizing bulk conductivity at elevated temperature.Three laboratory methods including divided-bar, line-source and optical scanning are widely applied in geothermal and petrophysical studies. In this study, these three methods were compared for determining the thermal conductivity tensor for anisotropic rocks. For this study, a representative collection of 80 crystalline rock samples from the KTB continental deep borehole was used. Despite substantial thermal inhomogeneity of rock thermal conductivity and high anisotropy, measurement results were in excellent agreement among the three methods.

The Influence of Grain Boundary Fluids on the Recrystallization Behavior in Calcite: A Comparison of "dry" and "wet" Marble Mylonites

NASA Astrophysics Data System (ADS)

Schenk, O.; Urai, J.; Evans, B.

2003-12-01

Carbonate rocks are able to accumulate large amounts of strain and deform crystal-plastically even at low p-T conditions and thus, marble sequences are often the site of strain localization in the upper crust during late-stage deformation in mountain building processes. In this study we sought to identify the effect of fluids on grain boundary morphology and recrystallization processes in marble mylonites during shear zone evolution, as fluids play a major role in the flow behavior of many rock materials during deformation (e.g. quartz, olivine, halite, feldspar). We compared calcite marble mylonites from two geological settings: (a) Schneeberg Complex, Southern Tyrole, Italy and (b) Naxos Metamorphic Core Complex, Greece. The shear zones of the selected areas are suitable for comparison, because they consist of similar lithology and the marble mylonites resemble each other in chemical composition. In addition, calcite-dolomite solvus geothermometry and TEM observations indicate similar p-T conditions for the shear zones formation. However, the two settings are different in the availability of fluids during the shear zone evolution: In the Schneeberg mylonites, both the alteration of minerals during retrograde metamorphism of neighboring micaschists and the existence of veins suggest that fluids were present during mylonitization. The absence of these features in the Naxos samples indicates that fluids were not present during deformation of these mylonites. This difference is also supported by the signature of stable isotopes. Microstructural investigations using optical and scanning electron microscopes on broken and planar surfaces did not indicate major differences between wet and dry mylonites: Grain boundaries of both types of samples display pores with shapes controlled by crystallography, and pore morphologies that are similar to observations from crack and grain-boundary healing experiments. Grain size reduction was predominantly the result of subgrain rotation recrystallization. However, the coarse grains inside the wet protomylonites (Schneeberg) are characterized by intracrystalline shear zones. With the exception of the intracrystalline shear zones, there were no obvious microstructural signatures that were obvious indicators of the presence of fluids, at least for these two field examples.

Heterogeneities of mechanical properties in potential geothermal reservoir rocks of the North German Basin

NASA Astrophysics Data System (ADS)

Reyer, D.; Philipp, S. L.

2012-04-01

Heterogeneous rock properties in terms of layering and complex infrastructure of fault zones are typical phenomena in sedimentary basins such as the North German Basin. To be able to model reservoir stimulation in layered stratifications and to better adapt the drilling strategy to the rock mechanical conditions it is important to have knowledge about the effects of heterogeneous rock properties on fracture propagation and fault zone infrastructure for typical sedimentary reservoir rocks in the North German Basin. Therefore we aim at quantifying these properties by performing structural geological field studies in outcrop analogues combined with laboratory analyses. The field studies in Rotliegend sandstones (Lower Permian), the sandstones of the Middle Bunter (Lower Triassic) and the sandstones of the Upper Keuper (Upper Triassic) focus on 1) host rock fracture systems and 2) fault zone infrastructure. We analyse quantitatively the dimension, geometry, persistence and connectivity of fracture systems separately for host rocks and fault damage zones. The results show that in rocks with distinctive layering (sandstones and shales) natural fractures are often restricted to individual layers, that is, they are stratabound. The probability of fracture arrest seems to depend on the stiffness contrast between the two layers and on the thickness of the softer layer. The field studies are complemented by systematic sampling to obtain mechanical property variations caused by the layering. For the samples we measure the parameters Young's modulus, compressive and tensile strengths, elastic strain energy, density and porosity. The results show that the mechanical properties vary considerably and many samples are clearly anisotropic. That is, samples taken perpendicular to layering commonly have higher strengths but lower stiffnesses than those taken parallel to layering. We combine the results of laboratory analyses and field measurements to specify the mechanical heterogeneities of the sedimentary reservoir rocks of the North German Basin and of the mechanical units of fault zones therein. To estimate the in situ rock properties at different depths it is further important to understand how rocks from outcrops differ from rocks at depth (for example due to alteration and removal of the overburden load). To answer these questions we analyse samples from drill cores from depths relevant for the use as geothermal reservoirs which are stratigraphically and lithologically equivalent to those taken in outcrop analogues. The results from drill-core sample analyses are then compared with the results from the outcrop samples. Another approach is to analyse how rock mechanical properties correlate with petrographic properties (e.g., mineral content, cementation, fabric, porosity) to use this knowledge to extrapolate the data to depth. Altogether these results will be very useful to make better assumptions on natural reservoir permeabilities and to better adapt the drilling and reservoir stimulation strategy to the rock mechanical conditions.

Effect of salt concentrations and drying methods on the quality and formation of histamine in dried milkfish (Chanos chanos).

PubMed

Hwang, Chiu-Chu; Lin, Chia-Min; Kung, Hsien-Feng; Huang, Ya-Ling; Hwang, Deng-Fwu; Su, Yi-Cheng; Tsai, Yung-Hsiang

2012-11-15

The effects of salt concentrations (0-15.0%) and drying methods on the quality of dried milkfish were studied. The results showed that the levels of aerobic plate counts, total coliform, water activity, moisture contents, total volatile basic nitrogen (TVBN) and thiobarbituric acid (TBA) of the dried milkfish samples prepared with the same drying method decreased with increased salt concentrations. The samples prepared with the cold-air drying method had better quality in term of lower TVBN and TBA values than those of samples prepared with other drying methods. The histamine contents in all samples, except two, prepared with various salt concentrations by different drying methods were less than 1.9 mg/100 g. Two unsalted samples prepared with hot-air drying at 35 °C and sun drying methods were found to contain histamine at levels of 249.7 and 67.4 mg/100 g, respectively, which were higher than the potential hazard level of 50 mg/100 g. Copyright © 2012 Elsevier Ltd. All rights reserved.

A rapid method for concentrating sedimentary organic matter for vitrinite reflectance analysis.

USGS Publications Warehouse

Barker, C.E.

1982-01-01

The tecnique discussed in this paper utilizes crushing, high-speed blending, and ultrasonic treatment to mechanically disaggregate rock and release the sedimentary organic matter (OM) in a suitable heavy liquid. This new method can provide freeze-dried concentrated OM in approximately 8 to 24 hours (longer time is necessary for removing carbonate). Under optimal conditions, it is possible to concentrate the OM and prepare a hardened epoxy microscope slide in about 24 hours. Subsequent grinding, polishing, and drying allows microscopic examination of the organic concentrate the next day.-from Author

Summary of Methods for Measuring Electrical Properties of Geological Strata to Estimate Electromagnetic Shielding Effectiveness

DTIC Science & Technology

1988-04-01

commercially for conventional surface resistivity measure- ments. Lead or copper wire wrapped around an insulating cable is used for the downhole...3 x 106 -- Igneous rocks, basic Augite porphyry Kola Peninsula 9.5-12.6 105-107 Dry Basalt Berestovetskoe 15.6 5 x 10 5 Dry Basalt Kutai 10.3 5 x...acidic Granite Azerbaidjan 3.0 x 107 -- Granite Ubinskoe 0.36 x 109 3.2 x 1018 Granite Kola Peninsula 0.16 x 105 0.3 x 1016 Granite porphyry 4.5 x 10 5

The effect of rock particles and D2O replacement on the flow behaviour of ice.

PubMed

Middleton, Ceri A; Grindrod, Peter M; Sammonds, Peter R

2017-02-13

Ice-rock mixtures are found in a range of natural terrestrial and planetary environments. To understand how flow processes occur in these environments, laboratory-derived properties can be extrapolated to natural conditions through flow laws. Here, deformation experiments have been carried out on polycrystalline samples of pure ice, ice-rock and D 2 O-ice-rock mixtures at temperatures of 263, 253 and 233 K, confining pressure of 0 and 48 MPa, rock fraction of 0-50 vol.% and strain-rates of 5 × 10 -7 to 5 × 10 -5  s -1 Both the presence of rock particles and replacement of H 2 O by D 2 O increase bulk strength. Calculated flow law parameters for ice and H 2 O-ice-rock are similar to literature values at equivalent conditions, except for the value of the rock fraction exponent, here found to be 1. D 2 O samples are 1.8 times stronger than H 2 O samples, probably due to the higher mass of deuterons when compared with protons. A gradual transition between dislocation creep and grain-size-sensitive deformation at the lowest strain-rates in ice and ice-rock samples is suggested. These results demonstrate that flow laws can be found to describe ice-rock behaviour, and should be used in modelling of natural processes, but that further work is required to constrain parameters and mechanisms for the observed strength enhancement.This article is part of the themed issue 'Microdynamics of ice'. © 2016 The Author(s).

The effect of rock particles and D2O replacement on the flow behaviour of ice

PubMed Central

Grindrod, Peter M.

2017-01-01

Ice–rock mixtures are found in a range of natural terrestrial and planetary environments. To understand how flow processes occur in these environments, laboratory-derived properties can be extrapolated to natural conditions through flow laws. Here, deformation experiments have been carried out on polycrystalline samples of pure ice, ice–rock and D2O-ice–rock mixtures at temperatures of 263, 253 and 233 K, confining pressure of 0 and 48 MPa, rock fraction of 0–50 vol.% and strain-rates of 5 × 10−7 to 5 × 10−5 s−1. Both the presence of rock particles and replacement of H2O by D2O increase bulk strength. Calculated flow law parameters for ice and H2O-ice–rock are similar to literature values at equivalent conditions, except for the value of the rock fraction exponent, here found to be 1. D2O samples are 1.8 times stronger than H2O samples, probably due to the higher mass of deuterons when compared with protons. A gradual transition between dislocation creep and grain-size-sensitive deformation at the lowest strain-rates in ice and ice–rock samples is suggested. These results demonstrate that flow laws can be found to describe ice–rock behaviour, and should be used in modelling of natural processes, but that further work is required to constrain parameters and mechanisms for the observed strength enhancement. This article is part of the themed issue ‘Microdynamics of ice’. PMID:28025298

Dragon Scales of Mars

NASA Image and Video Library

2017-07-11

This intriguing surface texture is the result of rock interacting with water, as observed by NASA's Mars Reconnaissance Orbiter. The rock was then eroded and later exposed to the surface. The pinkish, almost dragon-like scaled texture represents Martian bedrock that has specifically altered into a clay-bearing rock. The nature of the water responsible for the alteration, and how it interacted with the rock to form the clay remains poorly understood. Not surprisingly, the study of such altered rocks on Mars is an area of active investigation by the Mars science community. Understanding such interactions, and how they happened, help scientists to understand the past climate on Mars, and if the red planet ever harbored life. Recent studies indicate that the early Martian climate may not have been as warm, wet, and Earth-like, as previously suggested. This is not a problem for finding life on Mars as one might think. Ongoing studies of dry and cold environments on Earth shows that life finds ways to adapt to such extremes. Such work provides hope for finding evidence for life on other planets, like Mars, someday. https://photojournal.jpl.nasa.gov/catalog/PIA21781

Lunar and Planetary Science XXXV: Mars: Gullies, Fluids, and Rocks

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Mars: Gullies, Fluids, and Rocks" included the following reports:Gullies on Mars and Constraints Imposed by Mars Global Surveyor Data; Gullies on Mars: Origin by Snow and Ice Melting and Potential for Life Based on Possible Analogs from Devon Island, High Arctic; Formation of Recent Martian Gullies by Avalanches of CO2 Frost; Martian Slope Streaks and Gullies: Origins as Dry Granular Flows; Depths and Geologic Setting of Northern Hemisphere Gullies (and Comparison to Their Southern Counterparts); Mars as a Salt-, Acid-, and Gas-Hydrate World; Composition of Simulated Martian Brines and Implications for the Origin of Martian Salts; Evaporation Rates of Brine on Mars; Hydrogeology of the Valles Marineris-Chaotic Terrain Transition Zone, Mars; Measured Fluid Flow in an Active H2O-CO2 Geothermal Well as an Analog to Fluid Flow in Fractures on Mars: Preliminary Report; Understanding Rock Breakdown on Earth and Mars: Geomorphological Concepts and Facet Mapping Methods; Classification and Distribution of Mars Pathfinder Rocks Using Quantitative Morphologic Indices; and Systematic Rock Classification in a Data-poor Environment: Application to Mars.

Image analysis for quantification of bacterial rock weathering.

PubMed

Puente, M Esther; Rodriguez-Jaramillo, M Carmen; Li, Ching Y; Bashan, Yoav

2006-02-01

A fast, quantitative image analysis technique was developed to assess potential rock weathering by bacteria. The technique is based on reduction in the surface area of rock particles and counting the relative increase in the number of small particles in ground rock slurries. This was done by recording changes in ground rock samples with an electronic image analyzing process. The slurries were previously amended with three carbon sources, ground to a uniform particle size and incubated with rock weathering bacteria for 28 days. The technique was developed and tested, using two rock-weathering bacteria Pseudomonas putida R-20 and Azospirillum brasilense Cd on marble, granite, apatite, quartz, limestone, and volcanic rock as substrates. The image analyzer processed large number of particles (10(7)-10(8) per sample), so that the weathering capacity of bacteria can be detected.

Mechanical and physical properties of hydrothermally altered rocks, Taupo Volcanic Zone, New Zealand

NASA Astrophysics Data System (ADS)

Wyering, L. D.; Villeneuve, M. C.; Wallis, I. C.; Siratovich, P. A.; Kennedy, B. M.; Gravley, D. M.; Cant, J. L.

2014-11-01

Mechanical characterization of hydrothermally altered rocks from geothermal reservoirs will lead to an improved understanding of rock mechanics in a geothermal environment. To characterize rock properties of the selected formations, we prepared samples from intact core for non-destructive (porosity, density and ultrasonic wave velocities) and destructive laboratory testing (uniaxial compressive strength). We characterised the hydrothermal alteration assemblage using optical mineralogy and existing petrography reports and showed that lithologies had a spread of secondary mineralisation that occurred across the smectite, argillic and propylitic alteration zones. The results from the three geothermal fields show a wide variety of physical rock properties. The testing results for the non-destructive testing shows that samples that originated from the shallow and low temperature section of the geothermal field had higher porosity (15 - 56%), lower density (1222 - 2114 kg/m3) and slower ultrasonic waves (1925 - 3512 m/s (vp) and 818 - 1980 m/s (vs)), than the samples from a deeper and higher temperature section of the field (1.5 - 20%, 2072 - 2837 kg/m3, 2639 - 4593 m/s (vp) and 1476 - 2752 m/s (vs), respectively). The shallow lithologies had uniaxial compressive strengths of 2 - 75 MPa, and the deep lithologies had strengths of 16 - 211 MPa. Typically samples of the same lithologies that originate from multiple wells across a field have variable rock properties because of the different alteration zones from which each sample originates. However, in addition to the alteration zones, the primary rock properties and burial depth of the samples also have an impact on the physical and mechanical properties of the rock. Where this data spread exists, we have been able to derive trends for this specific dataset and subsequently have gained an improved understanding of how hydrothermal alteration affects physical and mechanical properties.

The Surface Chemical Composition of Lunar Samples and Its Significance for Optical Properties

NASA Technical Reports Server (NTRS)

Gold, T.; Bilson, E.; Baron, R. L.

1976-01-01

The surface iron, titanium, calcium, and silicon concentration in numerous lunar soil and rock samples was determined by Auger electron spectroscopy. All soil samples show a large increase in the iron to oxygen ratio compared with samples of pulverized rock or with results of the bulk chemical analysis. A solar wind simulation experiment using 2 keV energy alpha -particles showed that an ion dose corresponding to approximately 30,000 years of solar wind increased the iron concentration on the surface of the pulverized Apollo 14 rock sample 14310 to the concentration measured in the Apollo 14 soil sample 14163, and the albedo of the pulverized rock decreased from 0.36 to 0.07. The low albedo of the lunar soil is related to the iron + titanium concentration on its surface. A solar wind sputter reduction mechanism is discussed as a possible cause for both the surface chemical and optical properties of the soil.

Partitioning and bioavailability of mercury in an experimentally acidified Wisconsin lake

USGS Publications Warehouse

Wiener, James G.; Fitzgerald, William F.; Watras, Carl J.; Rada, Ronald G.

1990-01-01

We studied the partitioning of mercury (Hg) among air, water, sediments and fish at Little Rock Lake, a clear water seepage lake in north-central Wisconsin. The lake was divided with a sea curtain into two basins, one acidified with sulfuric acid to pH 5.6 for two years and the other an untreated reference site (mean pH 6.1), to document the effects of acidification. Trace-metal-free protocols were used to measure Hg at the picomolar level in air and water. Total gaseous Hg in air samples averaged 2.0 ng/m3. Total Hg in unfiltered water samples collected in 1986 after the fall overturn averaged about 1 ng/L in the acidified and reference basins. Mercury in surficial sediments was strongly correlated with volatile matter content and ranged from 10 to about 170 ng/g (dry weight) in both basins. Total Hg concentrations in whole, calendar age-1 yellow perch (Perca flavescens), sampled after one year of residence in the lake, averaged 114 ng/g (fresh weight) in the reference basin and 135 ng/g in the acidified basin – a highly significant (p < 0.01) difference. The mean whole-body burden (quantity) of Hg in age-1 perch did not differ between basins after the first year, but was significantly greater in the treatment basin than in the reference basin after the second year of acidification. Differences between the two basins in the bioaccumulation of Hg were attributed to internal (within-lake) processes that influence the bioavailability of the metal. An initial Hg budget for the treatment basin of Little Rock Lake showed that atmospheric deposition and sedimentary remobilization of Hg are potentially important processes influencing its biogeochemical cycling and uptake by fish.

An Examination of the Space Weathering Patina of Lunar Rock 76015

NASA Technical Reports Server (NTRS)

Noble, S.; Chrisoffersen, R.; Rahman, Z.

2011-01-01

Space weathering discussions have generally centered around soils but exposed rocks will also incur the effects of weathering. Rocks have much longer surface lifetimes than an individual soil grain and thus record a longer history of exposure. By studying the weathering products which have built up on a rock surface, we can gain a deeper perspective on the weathering process and better assess the relative importance of various weathering components. The weathered coating, or patina, of the lunar rock 76015 has been previously studied under SEM and also by TEM using ultramicrotome sample preparation methods. However, to really understand the products involved in creating these coatings, it is helpful to examine the patina in cross section, something which is now possible though the use of Focused Ion Beam (FIB) sample prep techniques, which allows us to preserve intact the delicate stratigraphy of the patina coating and provides a unique cross-sectional view of the space weathering process. Several samples have been prepared from the rock and the coatings are found to be quite variable in thickness and composition from one sample to the next.

Support services relating to geothermal programs. Final report

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

Not Available

1981-08-01

Activities designed to assist in the assessment of processes through which geopressured methane production and geopressure-geothermal power can be increased are discussed. Progress is reported on the following: general support, hot-dry-rock review, R and D plan, and the Edna Delcambre final report. (MHR)

Reappraisal of hydrocarbon biomarkers in Archean rocks

PubMed Central

French, Katherine L.; Hallmann, Christian; Hope, Janet M.; Schoon, Petra L.; Zumberge, J. Alex; Hoshino, Yosuke; Peters, Carl A.; George, Simon C.; Love, Gordon D.; Brocks, Jochen J.; Buick, Roger; Summons, Roger E.

2015-01-01

Hopanes and steranes found in Archean rocks have been presented as key evidence supporting the early rise of oxygenic photosynthesis and eukaryotes, but the syngeneity of these hydrocarbon biomarkers is controversial. To resolve this debate, we performed a multilaboratory study of new cores from the Pilbara Craton, Australia, that were drilled and sampled using unprecedented hydrocarbon-clean protocols. Hopanes and steranes in rock extracts and hydropyrolysates from these new cores were typically at or below our femtogram detection limit, but when they were detectable, they had total hopane (<37.9 pg per gram of rock) and total sterane (<32.9 pg per gram of rock) concentrations comparable to those measured in blanks and negative control samples. In contrast, hopanes and steranes measured in the exteriors of conventionally drilled and curated rocks of stratigraphic equivalence reach concentrations of 389.5 pg per gram of rock and 1,039 pg per gram of rock, respectively. Polycyclic aromatic hydrocarbons and diamondoids, which exceed blank concentrations, exhibit individual concentrations up to 80 ng per gram of rock in rock extracts and up to 1,000 ng per gram of rock in hydropyrolysates from the ultraclean cores. These results demonstrate that previously studied Archean samples host mixtures of biomarker contaminants and indigenous overmature hydrocarbons. Therefore, existing lipid biomarker evidence cannot be invoked to support the emergence of oxygenic photosynthesis and eukaryotes by ∼2.7 billion years ago. Although suitable Proterozoic rocks exist, no currently known Archean strata lie within the appropriate thermal maturity window for syngenetic hydrocarbon biomarker preservation, so future exploration for Archean biomarkers should screen for rocks with milder thermal histories. PMID:25918387

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

NASA Astrophysics Data System (ADS)

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

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

Stress-dependent elastic properties of shales—laboratory experiments at seismic and ultrasonic frequencies

NASA Astrophysics Data System (ADS)

Szewczyk, Dawid; Bauer, Andreas; Holt, Rune M.

2018-01-01

Knowledge about the stress sensitivity of elastic properties and velocities of shales is important for the interpretation of seismic time-lapse data taken as part of reservoir and caprock surveillance of both unconventional and conventional oil and gas fields (e.g. during 4-D monitoring of CO2 storage). Rock physics models are often developed based on laboratory measurements at ultrasonic frequencies. However, as shown previously, shales exhibit large seismic dispersion, and it is possible that stress sensitivities of velocities are also frequency dependent. In this work, we report on a series of seismic and ultrasonic laboratory tests in which the stress sensitivity of elastic properties of Mancos shale and Pierre shale I were investigated. The shales were tested at different water saturations. Dynamic rock engineering parameters and elastic wave velocities were examined on core plugs exposed to isotropic loading. Experiments were carried out in an apparatus allowing for static-compaction and dynamic measurements at seismic and ultrasonic frequencies within single test. For both shale types, we present and discuss experimental results that demonstrate dispersion and stress sensitivity of the rock stiffness, as well as P- and S-wave velocities, and stiffness anisotropy. Our experimental results show that the stress-sensitivity of shales is different at seismic and ultrasonic frequencies, which can be linked with simultaneously occurring changes in the dispersion with applied stress. Measured stress sensitivity of elastic properties for relatively dry samples was higher at seismic frequencies however, the increasing saturation of shales decreases the difference between seismic and ultrasonic stress-sensitivities, and for moist samples stress-sensitivity is higher at ultrasonic frequencies. Simultaneously, the increased saturation highly increases the dispersion in shales. We have also found that the stress-sensitivity is highly anisotropic in both shales and that in some of the cases higher stress-sensitivity of elastic properties can be seen in the direction parallel to the bedding plane.

Occurrence and Distribution of Organic Wastewater Compounds in Rock Creek Park, Washington, D.C., 2007-08

USGS Publications Warehouse

Phelan, Daniel J.; Miller, Cherie V.

2010-01-01

The U.S. Geological Survey, and the National Park Service Police Aviation Group, conducted a high-resolution, low-altitude aerial thermal infrared survey of the Washington, D.C. section of Rock Creek Basin within the Park boundaries to identify specific locations where warm water was discharging from seeps or pipes to the creek. Twenty-three stream sites in Rock Creek Park were selected based on the thermal infrared images. Sites were sampled during the summers of 2007 and 2008 for the analysis of organic wastewater compounds to verify potential sources of sewage and other anthropogenic wastewater. Two sets of stormwater samples were collected, on June 27-28 and September 6, 2008, at the Rock Creek at Joyce Road water-quality station using an automated sampler that began sampling when a specified stage threshold value was exceeded. Passive-sampler devices that accumulate organic chemicals over the duration of deployment were placed in July 2008 at the five locations that had the greatest number of detections of organic wastewater compounds from the June 2007 base-flow sampling. During the 2007 base-flow synoptic sampling, there were ubiquitous low-level detections of dissolved organic wastewater indicator compounds such as DEET, caffeine, HHCB, and organophosphate flame retardants at more than half of the 23 sites sampled in Rock Creek Park. Concentrations of DEET and caffeine in the tributaries to Rock Creek were variable, but in the main stem of Rock Creek, the concentrations were constant throughout the length of the creek, which likely reflects a distributed source. Organophosphate flame retardants in the main stem of Rock Creek were detected at estimated concentrations of 0.2 micrograms per liter or less, and generally did not increase with distance downstream. Overall, concentrations of most wastewater indicators in whole-water samples in the Park were similar to the concentrations found at the upstream sampling station at the Maryland/District of Columbia boundary. Polycyclic aromatic hydrocarbons were the dominant organic compounds found in the stormwater samples at the Joyce Road station. Polycyclic aromatic hydrocarbons were consistently found in higher concentrations either in sediment or in whole-water samples than in the dissolved samples collected during base-flow conditions at the 23 synoptic sites, or in the Joyce Road station stormwater samples.

Petrology of lunar rocks and implication to lunar evolution

NASA Technical Reports Server (NTRS)

Ridley, W. I.

1976-01-01

Recent advances in lunar petrology, based on studies of lunar rock samples available through the Apollo program, are reviewed. Samples of bedrock from both maria and terra have been collected where micrometeorite impact penetrated the regolith and brought bedrock to the surface, but no in situ cores have been taken. Lunar petrogenesis and lunar thermal history supported by studies of the rock sample are discussed and a tentative evolutionary scenario is constructed. Mare basalts, terra assemblages of breccias, soils, rocks, and regolith are subjected to elemental analysis, mineralogical analysis, trace content analysis, with studies of texture, ages and isotopic composition. Probable sources of mare basalts are indicated.

Origins, characteristics, controls, and economic viabilities of deep- basin gas resources

USGS Publications Warehouse

Price, L.C.

1995-01-01

Dry-gas deposits (methane ???95% of the hydrocarbon (HC) gases) are thought to originate from in-reservoir thermal cracking of oil and C2+ HC gases to methane. However, because methanes from Anadarko Basin dry-gas deposits do not carry the isotopic signature characteristics of C15+ HC destruction, an origin of these methanes from this process is considered improbable. Instead, the isotopic signature of these methanes suggests that they were cogenerated with C15+ HC's. Only a limited resource of deep-basin gas deposits may be expected by the accepted model for the origin of dry-gas deposits because of a limited number of deep-basin oil deposits originally available to be thermally converted to dry gas. However, by the models of this paper (inefficient source-rock oil and gas expulsion, closed fluid systems in petroleum-basin depocenters, and most dry-gas methane cogenerated with C15+ HC's), very large, previously unrecognized, unconventional, deep-basin gas resources are expected. -from Author

Brittleness Effect on Rock Fatigue Damage Evolution

NASA Astrophysics Data System (ADS)

Nejati, Hamid Reza; Ghazvinian, Abdolhadi

2014-09-01

The damage evolution mechanism of rocks is one of the most important aspects in studying of rock fatigue behavior. Fatigue damage evolution of three rock types (onyx marble, sandstone and soft limestone) with different brittleness were considered in the present study. Intensive experimental tests were conducted on the chosen rock samples and acoustic emission (AE) sensors were used in some of them to monitor the fracturing process. Experimental tests indicated that brittleness strongly influences damage evolution of rocks in the course of static and dynamic loading. AE monitoring revealed that micro-crack density induced by the applied loads during different stages of the failure processes increases as rock brittleness increases. Also, results of fatigue tests on the three rock types indicated that the rock with the most induced micro-cracks during loading cycles has the least fatigue life. Furthermore, the condition of failure surfaces of the studied rocks samples, subjected to dynamic and static loading, were evaluated and it was concluded that the roughness of failure surfaces is influenced by loading types and rock brittleness. Dynamic failure surfaces were rougher than static ones and low brittle rock demonstrate a smoother failure surface compared to high brittle rock.

The ammonium content in the Malayer igneous and metamorphic rocks (Sanandaj-Sirjan Zone, Western Iran)

NASA Astrophysics Data System (ADS)

Ahadnejad, Vahid; Hirt, Ann Marie; Valizadeh, Mohammad-Vali; Bokani, Saeed Jabbari

2011-04-01

The ammonium (NH4+) contents of the Malayer area (Western Iran) have been determined by using the colorimetric method on 26 samples from igneous and metamorphic rocks. This is the first analysis of the ammonium contents of Iranian metamorphic and igneous rocks. The average ammonium content of metamorphic rocks decreases from low-grade to high-grade metamorphic rocks (in ppm): slate 580, phyllite 515, andalusite schist 242. In the case of igneous rocks, it decreases from felsic to mafic igneous types (in ppm): granites 39, monzonite 20, diorite 17, gabbro 10. Altered granitic rocks show enrichment in NH4+ (mean 61 ppm). The high concentration of ammonium in Malayer granites may indicate metasedimentary rocks as protoliths rather than meta-igneous rocks. These granitic rocks (S-types) have high K-bearing rock-forming minerals such as biotite, muscovite and K-feldspar which their potassium could substitute with ammonium. In addition, the high ammonium content of metasediments is probably due to inheritance of nitrogen from organic matter in the original sediments. The hydrothermally altered samples of granitic rocks show highly enrichment of ammonium suggesting external sources which intruded additional content by either interaction with metasedimentary country rocks or meteoritic solutions.

Modeling and optimization of red currants vacuum drying process by response surface methodology (RSM).

PubMed

Šumić, Zdravko; Vakula, Anita; Tepić, Aleksandra; Čakarević, Jelena; Vitas, Jasmina; Pavlić, Branimir

2016-07-15

Fresh red currants were dried by vacuum drying process under different drying conditions. Box-Behnken experimental design with response surface methodology was used for optimization of drying process in terms of physical (moisture content, water activity, total color change, firmness and rehydratation power) and chemical (total phenols, total flavonoids, monomeric anthocyanins and ascorbic acid content and antioxidant activity) properties of dried samples. Temperature (48-78 °C), pressure (30-330 mbar) and drying time (8-16 h) were investigated as independent variables. Experimental results were fitted to a second-order polynomial model where regression analysis and analysis of variance were used to determine model fitness and optimal drying conditions. The optimal conditions of simultaneously optimized responses were temperature of 70.2 °C, pressure of 39 mbar and drying time of 8 h. It could be concluded that vacuum drying provides samples with good physico-chemical properties, similar to lyophilized sample and better than conventionally dried sample. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ambient air metallic pollutant study at HAF areas during 2013-2014

NASA Astrophysics Data System (ADS)

Fang, Guor-Cheng; Kuo, Yu-Chen; Zhuang, Yuan-Jie

2015-05-01

This study characterized diurnal variations of the total suspended particulate (TSP) concentrations, dry deposition flux and dry deposition velocity of metallic elements at Taichung Harbor (Harbor), Gong Ming Junior High School (Airport) and Sha lu Farmland (Farmland) sampling sites in central Taiwan between August, 2013 and July, 2014 in this study. The result indicated that: 1) the ambient air particulate concentrations, dry depositions were displayed as Harbor > Farmland > Airport during the day time sampling period. However, dry deposition velocities were shown as Airport > Harbor > Farmland for this study. 2) The ambient air particulate concentrations, dry depositions were displayed as Airport > Harbor > Farmland during the night time sampling period. However, dry deposition velocities were shown as Farmland > Harbor > Airport for this study. 3) The metallic element Zn has the average highest concentrations at Airport, Harbor and Farmland among all the metallic elements during the day time sampling period in this study. 4) There were significant differences for the metallic elements (Cr, Cu, Zn and Pb) in dry depositions at these three characteristic sampling sites (HAF) for the night time sampling period. The only exception is metallic element Cd. It displayed that there were no significant differences for the metallic element Cd at the Airport and Farmland sampling sites during the night time sampling period. 5) The average highest values for the metallic element Cu in TSP among the three characteristic sampling sites occurred during the fall and winter seasons for this study. As for the dry depositions, the average highest values in dry deposition among the three characteristic sampling sites occurred during the spring and summer seasons for this study. 6) The average highest values for the metallic element Cd in TSP among the three characteristic sampling sites occurred during the spring and summer seasons for this study. As for the dry depositions, the average highest values in dry deposition among the three characteristic sampling sites occurred during fall and winter for this study.

Integrated approach for quantification of fractured tight reservoir rocks: Porosity, permeability analyses and 3D fracture network characterisation on fractured dolomite samples

NASA Astrophysics Data System (ADS)

Voorn, Maarten; Barnhoorn, Auke; Exner, Ulrike; Baud, Patrick; Reuschlé, Thierry

2015-04-01

Fractured reservoir rocks make up an important part of the hydrocarbon reservoirs worldwide. A detailed analysis of fractures and fracture networks in reservoir rock samples is thus essential to determine the potential of these fractured reservoirs. However, common analyses on drill core and plug samples taken from such reservoirs (including hand specimen analysis, thin section analysis and laboratory porosity and permeability determination) suffer from various problems, such as having a limited resolution, providing only 2D and no internal structure information, being destructive on the samples and/or not being representative for full fracture networks. In this study, we therefore explore the use of an additional method - non-destructive 3D X-ray micro-Computed Tomography (μCT) - to obtain more information on such fractured samples. Seven plug-sized samples were selected from narrowly fractured rocks of the Hauptdolomit formation, taken from wellbores in the Vienna Basin, Austria. These samples span a range of different fault rocks in a fault zone interpretation, from damage zone to fault core. 3D μCT data is used to extract porosity, fracture aperture, fracture density and fracture orientations - in bulk as well as locally. The 3D analyses are complemented with thin sections made to provide some 2D information with a much higher detail than the μCT data. Finally, gas- and water permeability measurements under confining pressure provide an important link (at least in order of magnitude) of the µCT results towards more realistic reservoir conditions. Our results show that 3D μCT can be applied efficiently on plug-sized samples of naturally fractured rocks, and that several important parameters can be extracted. μCT can therefore be a useful addition to studies on such reservoir rocks, and provide valuable input for modelling and simulations. Also permeability experiments under confining pressure provide important additional insights. Combining these and other methods can therefore be a powerful approach in microstructural analysis of reservoir rocks, especially when applying the concepts that we present (on a small set of samples) in a larger study, in an automated and standardised manner.

Multifractal magnetic susceptibility distribution models of hydrothermally altered rocks in the Needle Creek Igneous Center of the Absaroka Mountains, Wyoming

USGS Publications Warehouse

Gettings, M.E.

2005-01-01

Magnetic susceptibility was measured for 700 samples of drill core from thirteen drill holes in the porphyry copper-molybdenum deposit of the Stinkingwater mining district in the Absaroka Mountains, Wyoming. The magnetic susceptibility measurements, chemical analyses, and alteration class provided a database for study of magnetic susceptibility in these altered rocks. The distribution of the magnetic susceptibilities for all samples is multi-modal, with overlapping peaked distributions for samples in the propylitic and phyllic alteration class, a tail of higher susceptibilities for potassic alteration, and an approximately uniform distribution over a narrow range at the highest susceptibilities for unaltered rocks. Samples from all alteration and mineralization classes show susceptibilities across a wide range of values. Samples with secondary (supergene) alteration due to oxidation or enrichment show lower susceptibilities than primary (hypogene) alteration rock. Observed magnetic susceptibility variations and the monolithological character of the host rock suggest that the variations are due to varying degrees of alteration of blocks of rock between fractures that conducted hydrothermal fluids. Alteration of rock from the fractures inward progressively reduces the bulk magnetic susceptibility of the rock. The model introduced in this paper consists of a simulation of the fracture pattern and a simulation of the alteration of the rock between fractures. A multifractal model generated from multiplicative cascades with unequal ratios produces distributions statistically similar to the observed distributions. The reduction in susceptibility in the altered rocks was modelled as a diffusion process operating on the fracture distribution support. The average magnetic susceptibility was then computed for each block. For the purpose of comparing the model results with observation, the simulated magnetic susceptibilities were then averaged over the same interval as the measured data. Comparisons of the model and data from drillholes show good but not perfect agreement. ?? 2005 Author(s). This work is licensed under a Creative Commons License.

Restoration and PDS Archive of Apollo Lunar Rock Sample Data

NASA Technical Reports Server (NTRS)

Garcia, P. A.; Todd, N. S.; Lofgren, G. E.; Stefanov, W. L.; Runco, S. K.; LaBasse, D.; Gaddis, L. R.

2011-01-01

In 2008, scientists at the Johnson Space Center (JSC) Lunar Sample Laboratory and Image Science & Analysis Laboratory (under the auspices of the Astromaterials Research and Exploration Science Directorate or ARES) began work on a 4-year project to digitize the original film negatives of Apollo Lunar Rock Sample photographs. These rock samples together with lunar regolith and core samples were collected as part of the lander missions for Apollos 11, 12, 14, 15, 16 and 17. The original film negatives are stored at JSC under cryogenic conditions. This effort is data restoration in the truest sense. The images represent the only record available to scientists which allows them to view the rock samples when making a sample request. As the negatives are being scanned, they are also being formatted and documented for permanent archive in the NASA Planetary Data System (PDS) archive. The ARES group is working collaboratively with the Imaging Node of the PDS on the archiving.

Assessment of hydrocarbon source rock potential of Polish bituminous coals and carbonaceous shales

USGS Publications Warehouse

Kotarba, M.J.; Clayton, J.L.; Rice, D.D.; Wagner, M.

2002-01-01

We analyzed 40 coal samples and 45 carbonaceous shale samples of varying thermal maturity (vitrinite reflectance 0.59% to 4.28%) from the Upper Carboniferous coal-bearing strata of the Upper Silesian, Lower Silesian, and Lublin basins, Poland, to evaluate their potential for generation and expulsion of gaseous and liquid hydrocarbons. We evaluated source rock potential based on Rock-Eval pyrolysis yield, elemental composition (atomic H/C and O/C), and solvent extraction yields of bitumen. An attempt was made to relate maceral composition to these source rock parameters and to composition of the organic matter and likely biological precursors. A few carbonaceous shale samples contain sufficient generation potential (pyrolysis assay and elemental composition) to be considered potential source rocks, although the extractable hydrocarbon and bitumen yields are lower than those reported in previous studies for effective Type III source rocks. Most samples analysed contain insufficient capacity for generation of hydrocarbons to reach thresholds required for expulsion (primary migration) to occur. In view of these findings, it is improbable that any of the coals or carbonaceous shales at the sites sampled in our study would be capable of expelling commercial amounts of oil. Inasmuch as a few samples contained sufficient generation capacity to be considered potential source rocks, it is possible that some locations or stratigraphic zones within the coals and shales could have favourable potential, but could not be clearly delimited with the number of samples analysed in our study. Because of their high heteroatomic content and high amount of asphaltenes, the bitumens contained in the coals are less capable of generating hydrocarbons even under optimal thermal conditions than their counterpart bitumens in the shales which have a lower heteroatomic content. Published by Elsevier Science B.V.

Understanding and Mitigating Reservoir Compaction: an Experimental Study on Sand Aggregates

NASA Astrophysics Data System (ADS)

Schimmel, M.; Hangx, S.; Spiers, C. J.

2016-12-01

Fossil fuels continue to provide a source for energy, fuels for transport and chemicals for everyday items. However, adverse effects of decades of hydrocarbons production are increasingly impacting society and the environment. Production-driven reduction in reservoir pore pressure leads to a poro-elastic response of the reservoir, and in many occasions to time-dependent compaction (creep) of the reservoir. In turn, reservoir compaction may lead to surface subsidence and could potentially result in induced (micro)seismicity. To predict and mitigate the impact of fluid extraction, we need to understand production-driven reservoir compaction in highly porous siliciclastic rocks and explore potential mitigation strategies, for example, by using compaction-inhibiting injection fluids. As a first step, we investigate the effect of chemical environment on the compaction behaviour of sand aggregates, comparable to poorly consolidated, highly porous sandstones. The sand samples consist of loose aggregates of Beaujean quartz sand, sieved into a grainsize fraction of 180-212 µm. Uniaxial compaction experiments are performed at an axial stress of 35 MPa and temperature of 80°C, mimicking conditions of reservoirs buried at three kilometres depth. The chemical environment during creep is either vacuum-dry or CO2-dry, or fluid-saturated, with fluids consisting of distilled water, acid solution (CO2-saturated water), alkaline solution (pH 9), aluminium solution (pH 3) and solution with surfactants (i.e., AMP). Preliminary results show that compaction of quartz sand aggregates is promoted in a wet environment compared to a dry environment. It is inferred that deformation is controlled by subcritical crack growth when dry and stress corrosion cracking when wet, both resulting in grain failure and subsequent grain rearrangement. Fluids inhibiting these processes, have the potential to inhibit aggregate compaction.

Some physical aspects of fluid-fluxed melting

NASA Astrophysics Data System (ADS)

Patiño Douce, A.

2012-04-01

Fluid-fluxed melting is thought to play a crucial role in the origin of many terrestrial magmas. We can visualize the fundamental physics of the process as follows. An infinitesimal amount of fluid infiltrates dry rock at the temperature of its dry solidus. In order to restore equilibrium the temperature must drop, so that enthalpy is released and immediately reabsorbed as enthalpy of melting. The amount of melt produced must be such that the energy balance and thermodynamic equilibrium conditions are simultaneously satisfied. We wish to understand how an initially dry rock melts in response to progressive fluid infiltration, under both batch and fractional melting constraints. The simplest physical model for this process is a binary system in which one of the components makes up a pure solid phase and the other component a pure fluid phase, and in which a binary melt phase exists over certain temperature range. Melting point depression is calculated under the assumption of ideal mixing. The equations of energy balance and thermodynamic equilibrium are solved simultaneously for temperature and melt fraction, using an iterative procedure that allows addition of fluid in infinitesimal increments. Batch melting and fractional melting are simulated by allowing successive melt increments to remain in the system (batch) or not (fractional). Despite their simplified nature, these calculations reveal some important aspects of fluid-fluxed melting. The model confirms that, if the solubility of the fluid in the melt is sufficiently high, fluid fluxed melting is an efficient mechanism of magma generation. One might expect that the temperature of the infiltrating fluid would have a significant effect on melt productivity, but the results of the calculations show this not to be the case, because a relatively small mass of low molecular weight fluid has a strong effect on the melting point of minerals with much higher molecular weights. The calculations reveal the somewhat surprising result that fluid infiltration produces more melt during fractional melting than during batch melting. This behavior, which is opposite to that of decompression melting of a dry solid, arises because the melting point depression effect of the added fluid is greater during fractional melting than during batch melting, which results in a greater release of enthalpy and, therefore, greater melt production for fractional melting than for batch melting, for the same total amount of fluid added. The difference may be considerable. As an example, suppose that 0.1 mols of H2O infiltrate 1 mol or silicate rock. Depending on the rock composition this may corresponds to ˜ 1 wt% H2O. For a given choice of model parameters (initial temperature, heat capacity and entropy of fusion), about 28% of the rock melts during fractional melting, versus some 23 % during batch melting. Fluid fluxing is a robust process of melt generation, without which magmatism at Earth's convergent plate margins would be impossible.

Microbial communities in carbonate rocks-from soil via groundwater to rocks.

PubMed

Meier, Aileen; Singh, Manu K; Kastner, Anne; Merten, Dirk; Büchel, Georg; Kothe, Erika

2017-09-01

Microbial communities in soil, groundwater, and rock of two sites in limestone were investigated to determine community parameters differentiating habitats in two lithostratigraphic untis. Lower Muschelkalk and Middle Muschelkalk associated soils, groundwater, and rock samples showed different, but overlapping microbial communities linked to carbon fluxes. The microbial diversities in soil were highest, groundwater revealed overlapping taxa but lower diversity, and rock samples were predominantly characterized by endospore forming bacteria and few archaea. Physiological profiles could establish a differentiation between habitats (soil, groundwater, rock). From community analyses and physiological profiles, different element cycles in limestone could be identified for the three habitats. While in soil, nitrogen cycling was identified as specific determinant, in rock methanogenesis linked carbonate rock to atmospheric methane cycles. These patterns specifically allowed for delineation of lithostratigraphic connections to physiological parameters. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rock sample brought to earth from the Apollo 12 lunar landing mission

NASA Technical Reports Server (NTRS)

1969-01-01

Close-up view of Apollo 12 sample 12,065 under observation in the Manned Spacecraft Center's Lunar Receiving Laboratory. This sample, collected during the second Apollo 12 extravehicular activity (EVA-2) of Astronauts Charles Conrad Jr., and Alan L. Bean, is a fine-grained rock. Note the glass-lined pits. An idea of the size of the rock can be gained by reference to the gauge on the bottom portion of the number meter.

Age and isotopic systematics of Cretaceous borehole and surface samples from the greater Los Angeles Basin region: Implications for the types of crust that might underlie Los Angeles and their distribution along late Cenozoic fault systems

USGS Publications Warehouse

Premo, Wayne R.; Morton, Douglas M.; Kistler, Ronald W.

2014-01-01

Nine U-Pb zircon ages were determined on plutonic rocks sampled from surface outcrops and rock chips of drill core from boreholes within the greater Los Angeles Basin region. In addition, lead-strontium-neodymium (Pb-Sr-Nd) whole-rock isotopic data were obtained for eight of these samples. These results help to characterize the crystalline basement rocks hidden in the subsurface and provide information that bears on the tectonic history of the myriad of fault systems that have dissected the Los Angeles region over the past 15 m.y. Seven of the nine samples have U-Pb ages ranging from 115 to 103 Ma and whole-rock Pb-Sr-Nd isotopic characteristics that indicate the crystalline basement underneath the greater Los Angeles Basin region is mostly part of the Peninsular Ranges batholith. Furthermore, these data are interpreted as evidence for (1) the juxtaposition of mid-Cretaceous, northern Peninsular Ranges batholith plutonic rocks against Late Cretaceous plutonic rocks of the Transverse Ranges in the San Fernando Valley, probably along the Verdugo fault; (2) the juxtaposition of older northwestern Peninsular Ranges batholith rocks against younger northeastern Peninsular Ranges batholith rocks in the northern Puente Hills, implying transposition of northeastern Peninsular Ranges batholith rocks to the west along unrecognized faults beneath the Chino Basin; and (3) juxtaposition of northern Peninsular Ranges batholith plutonic rocks against Late Cretaceous plutonic rocks of the Transverse Ranges along the San Jose fault in the northern San Jose Hills at Ganesha Park. These mainly left-lateral strike-slip faults of the eastern part of the greater Los Angeles Basin region could be the result of block rotation within the adjacent orthogonal, right-lateral, Elsinore-Whittier fault zone to the west and the subparallel San Jacinto fault zone to the east. The San Andreas fault system is the larger, subparallel, driving force further to the east.

Elemental Geochemistry of Samples From Fault Segments of the San Andreas Fault Observatory at Depth (SAFOD) Drill Hole

NASA Astrophysics Data System (ADS)

Tourscher, S. N.; Schleicher, A. M.; van der Pluijm, B. A.; Warr, L. N.

2006-12-01

Elemental geochemistry of mudrock samples from phase 2 drilling of the San Andreas Fault Observatory at Depth (SAFOD) is presented from bore hole depths of 3066 m to 3169 m and from 3292 m to 3368 m, which contain a creeping section and main trace of the fault, respectively. In addition to preparation and analysis of whole rock sample, fault grains with neomineralized, polished surfaces were hand picked from well-washed whole rock samples, minimizing the potential contamination from drilling mud and steel shavings. The separated fractions were washed in deionized water, powdered using a mortar and pestle, and analyzed using an Inductively Coupled Plasma- Optical Emission Spectrometer for major and minor elements. Based on oxide data results, systematic differences in element concentrations are observed between the whole rock and fault rock. Two groupings of data points are distinguishable in the regions containing the main trace of the fault, a shallow part (3292- 3316 m) and a deeper section (3320-3368 m). Applying the isocon method, assuming Zr and Ti to be immobile elements in these samples, indicates a volume loss of more than 30 percent in the shallow part and about 23 percent in the deep part of the main trace. These changes are minimum estimates of fault-related volume loss, because the whole rock from drilling samples contains variable amount of fault rock as well. Minimum estimates for volume loss in the creeping section of the fault are more than 50 percent when using the isocon method, comparing whole rock to plucked fault rock. The majority of the volume loss in the fault rocks is due to the dissolution and loss of silica, potassium, aluminum, sodium and calcium, whereas (based on oxide data) the mineralized surfaces of fractures appear to be enriched in Fe and Mg. The large amount of element mobility within these fault traces suggests extensive circulation of hydrous fluids along fractures that was responsible for progressive dissolution and leaching of the wall rock during faulting.

Sulfur species in source rock bitumen before and after hydrous pyrolysis determined by X-ray absorption near-edge structure

USGS Publications Warehouse

Bolin, Trudy B.; Birdwell, Justin E.; Lewan, Michael; Hill, Ronald J.; Grayson, Michael B.; Mitra-Kirtley, Sudipa; Bake, Kyle D.; Craddock, Paul R.; Abdallah, Wael; Pomerantz, Andrew E.

2016-01-01

The sulfur speciation of source rock bitumen (chloroform-extractable organic matter in sedimentary rocks) was examined using sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy for a suite of 11 source rocks from around the world. Sulfur speciation was determined for both the native bitumen in thermally immature rocks and the bitumen produced by thermal maturation of kerogen via hydrous pyrolysis (360 °C for 72 h) and retained within the rock matrix. In this study, the immature bitumens had higher sulfur concentrations than those extracted from samples after hydrous pyrolysis. In addition, dramatic and systematic evolution of the bitumen sulfur moiety distributions following artificial thermal maturation was observed consistently for all samples. Specifically, sulfoxide sulfur (sulfur double bonded to oxygen) is abundant in all immature bitumen samples but decreases substantially following hydrous pyrolysis. The loss in sulfoxide sulfur is associated with a relative increase in the fraction of thiophene sulfur (sulfur bonded to aromatic carbon) to the extent that thiophene is the dominant sulfur form in all post-pyrolysis bitumen samples. This suggests that sulfur moiety distributions might be used for estimating thermal maturity in source rocks based on the character of the extractable organic matter.

Physical and chemical properties of submarine basaltic rocks from the submarine flanks of the Hawaiian Islands

USGS Publications Warehouse

Yokose, H.; Lipman, P.W.; Kanamatsu, T.

2005-01-01

To evaluate physical and chemical diversity in submarine basaltic rocks, approximately 280 deep submarine samples recovered by submersibles from the underwater flanks of the Hawaiian Islands were analyzed and compared. Based on observations from the submersibles and hand specimens, these samples were classified into three main occurrence types (lavas, coarse-grained volcaniclastic rocks, and fine-grained sediments), each with several subtypes. The whole-rock sulfur content and porosity in submarine basaltic rocks, recovered from depths greater than 2000 m, range from < 10 ppm and 2 vol.% to 2200 ppm and 47 vol.%, respectively. These wide variations cannot be due just to different ambient pressures at the collection depths, as inferred previously for submarine erupted lavas. The physical and chemical properties of the recovered samples, especially a combination of three whole-rock parameters (Fe-oxidation state, Sulfur content, and Porosity), are closely related to the occurrence type. The FSP triangular diagram is a valuable indicator of the source location of basaltic fragments deposited in deep submarine areas. This diagram can be applied to basaltic rocks such as clasts in debris-flow deposits, submarine-emplaced lava flows that may have crossed the shoreline, and slightly altered geological samples. ?? 2005 Elsevier B.V. All rights reserved.

Investigating the salinization and freshening processes of coastal groundwater resources in Urmia aquifer, NW Iran.

PubMed

Amiri, Vahab; Nakhaei, Mohammad; Lak, Razyeh; Kholghi, Majid

2016-04-01

This paper presents the results of an assessment about interaction between Urmia Lake (UL) and coastal groundwater in the Urmia aquifer (UA). This aquifer is the most significant contributor to the freshwater supply of the coastal areas. The use of hydrochemical facies can be very useful to identify the saltwater encroachment or freshening phases in the coastal aquifers. In this study, the analysis of salinization/freshening processes was carried out through the saturation index (SI), ionic deltas (Δ), binary diagrams, and hydrochemical facies evolution (HFE) diagram. Based on the Gibbs plot, the behavior of the major ions showed that the changes in the chemical composition of the groundwater are mainly controlled by the water-soil/rock interaction zone and few samples are relatively controlled by evaporation. A possible explanation for this phenomenon is that the deposited chloride and sulfate particles can form the minor salinity source in some coastal areas when washed down by precipitation. The SI calculations showed that all groundwater samples, collected in these periods, show negative saturation indices, which indicate undersaturation with respect to anhydrite, gypsum, and halite. In addition, except in a few cases, all other samples showed the undersaturation with respect to the carbonate minerals such as aragonite, calcite, and dolomite. Therefore, these minerals are susceptible to dissolution. In the dry season, the SI calculations showed more positive values with respect to dolomite, especially in the northern part of UA, which indicated a higher potential for precipitation and deposition of dolomite. The percentage of saltwater in the groundwater samples of Urmia plain was very low, ranging between 0.001 and 0.79 % in the wet season and 0.0004 and 0.81 % in the dry season. The results of HFE diagram, which was taken to find whether the aquifer was in the saltwater encroachment phase or in the freshening phase, indicated that except for a few wells near the coast, there is very little hydraulic interaction between UA and UL. In this coastal area, most of the samples that were collected repeatedly in both wet and dry seasons showed the same hydrochemical facies, which suggested that the seasonal groundwater fluctuations cannot significantly change the chemical composition of groundwater.

Magmatic evolution of Panama Canal volcanic rocks: A record of arc processes and tectonic change

PubMed Central

Cardona, Agustin; Montes, Camilo; Foster, David; Jaramillo, Carlos

2017-01-01

Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21–25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile element enrichments, a THI of 0.88, and a H2Ocalc of >3 wt. %. In contrast, the Miocene Pedro Miguel and Late Basalt Fm. exhibit reduced Nb-Ta anomalies, flattened REE curves, depleted fluid mobile elements, a THI of 1.45, a H2Ocalc of <1 wt. %, and plot in mid-ocean ridge/back-arc basin fields. Geochemical modeling of Miocene rocks indicates 0.5–0.1 kbar crystallization depths of hot (1100–1190°C) magmas in which most compositional diversity can be explained by fractional crystallization (F = 0.5). However, the most silicic lavas (Las Cascadas Fm.) require an additional mechanism, and assimilation-fractional-crystallization can reproduce observed compositions at reasonable melt fractions. The Canal volcanic rocks, therefore, change from hydrous basaltic pyroclastic deposits typical of mantle-wedge-derived magmas, to hot, dry bi-modal magmatism at the Oligocene-Miocene boundary. We suggest the primary reason for the change is onset of arc perpendicular extension localized to central Panama. High-resolution mapping along the Panama Canal has revealed a sequence of inward dipping maar-diatreme pyroclastic pipes, large basaltic sills, and bedded silicic ignimbrites and tuff deposits. These volcanic bodies intrude into the sedimentary Canal Basin and are cut by normal and subsequently strike-slip faults. Such pyroclastic pipes and basaltic sills are most common in extensional arc and large igneous province environments. Overall, the change in volcanic edifice form and geochemistry are related to onset of arc perpendicular extension, and are consistent with the idea that Panama arc crust fractured during collision with South America forming the observed Canal extensional zone. PMID:28489866

Rates of Eolian Rock Abrasion in the Ice-Free Valleys, Antarctica

NASA Astrophysics Data System (ADS)

Hallet, B.; Malin, M. C.; Sletten, R. S.

2016-12-01

Eolian abrasion is a principal surface process in dry regions of Earth and Mars and there is evidence for wind processes active on Venus and Titan. Rock abrasion also has practical significance in diverse fields ranging from preservation of cultural material (artifacts, monuments) to damage of solar panels and windshields in arid regions. Despite its scientific and practical importance, and there have ben only few studies that define rates of rock abrasion quantitatively under natural conditions. Herein we report abrasion rates that have been exceptionally well characterized through a unique long-term (30+-year) field experiment in the ice-free McMurdo Dry Valleys, Antarctica. In 1983 and 1984, over 5000 rock targets of several lithologies (25.4 mm-diameter and 5 mm-thick disks of dolerite, basalt, tuff and sandstone) were installed at five heights (7,14, 21, 35, and 70 cm) facing the 4 cardinal directions at 10 locations (one additional site contains fewer targets). Sequential collections of rock targets exposed to abrasion enable definition of mass loss after 1, 5, 10, 30 and 31 years of exposure; the latter were retrieved during the 2014-2015 season. The abrasion rates generally show striking consistency for each lithology at any site; the multiple targets permit definition of intrinsic differences in mass loss. The rates vary considerably from site to site owing to differences in availability of transportable sediment, wind regime, and surface roughness, and at each site, owing to target orientation relative to the dominant winds and, secondarily, to height above the ground. For the hardest targets, basalt and dolerite, mass loss in 30+ years ranged from essentially zero at some sites to 1/3 of the deployed mass (2.59 g; equivalent to a rock thickness >1.8 mm) where abrasion was most active (Site 7, Central Wright Valley). The tuff targets showed the greatest mass loss, and in many cases were entirely abraded away by the end of the experiment.Current work is focused on understanding the spatial and directional variation in measured mass losses based on a wealth of information.

Mars Rock Analysis Briefing

NASA Image and Video Library

2013-03-12

David Blake, principal investigator for Curiosity's Chemistry and Mineralogy investigation at NASA's Ames Research Center in Calif., speaks at a news conference presenting findings of the Curiosity rover's analysis of the first sample of rock powder collected on Mars, Tuesday, March 12, 2013 in Washington. The rock sample collected shows ancient Mars could have supported living microbes. Photo Credit: (NASA/Carla Cioffi)

Effects of shallow basaltic intrusion into pyroclastic deposits, Grants Ridge, New Mexico, USA

NASA Astrophysics Data System (ADS)

WoldeGabriel, Giday; Keating, Gordon N.; Valentine, Greg A.

1999-10-01

A localized aureole up to 10 m wide developed around a 150-m-wide, 2.6 Ma basaltic plug at Grants Ridge, New Mexico. The plug intruded into nonwelded, pumice-rich compositionally homogenous tuff and volcaniclastic sediments of similar age (3.3 Ma). Color variation (pinkish to orange), strong local contact welding, brecciation, partial melting, and stoping characterize the host rock within the contact zone. Despite the high-temperature basaltic intrusion, there is no indication of extensive fluid-driven convective heat transfer and pervasive hydrothermal circulation and alteration of the country rock. The proportion of volcanic glass, loss on ignition (LOI), fluorine, iron, and some trace and rare earth element contents in the host rocks are somewhat depleted at the contact of the intrusion. Conversely, the degree of devitrification and the potassium content are higher along the contact. Vapor-phase expulsion of elemental species as complexes of fluoride, chloride, hydroxide, sulfide, and carbon dioxide may have been responsible for the minor depletion of the elements during the devitrification of silicic glass at near-solidus temperature related to the basaltic intrusion. The results of finite-difference numerical modeling of the intrusion as a dry, conduction-dominated system agree well with geochemical and mineralogical data. Contact welding of the host rocks apparently occurred at temperatures >700°C under a density-driven lateral load of approximately 1 MPa, corresponding to the observed depth below the former ground surface of ˜100 m. Other physical changes in the first 10 m of host rock, represented by partial devitrification and color changes, apparently occurred at temperatures of 500-600°C, which probably persisted for up to 55 years after the emplacement of the basaltic plug. Devitrification is generally enhanced by the presence of aqueous fluids; however, the abundance of volcanic glass within a short distance (˜10 m) from the plug is consistent with our inference that the plug intruded into a dry (unsaturated) environment.

Comparison of Crack Initiation, Propagation and Coalescence Behavior of Concrete and Rock Materials

NASA Astrophysics Data System (ADS)

Zengin, Enes; Abiddin Erguler, Zeynal

2017-04-01

There are many previously studies carried out to identify crack initiation, propagation and coalescence behavior of different type of rocks. Most of these studies aimed to understand and predict the probable instabilities on different engineering structures such as mining galleries or tunnels. For this purpose, in these studies relatively smaller natural rock and synthetic rock-like models were prepared and then the required laboratory tests were performed to obtain their strength parameters. By using results provided from these models, researchers predicted the rock mass behavior under different conditions. However, in the most of these studies, rock materials and models were considered as contains none or very few discontinuities and structural flaws. It is well known that rock masses naturally are extremely complex with respect to their discontinuities conditions and thus it is sometimes very difficult to understand and model their physical and mechanical behavior. In addition, some vuggy rock materials such as basalts and limestones also contain voids and gaps having various geometric properties. Providing that the failure behavior of these type of rocks controlled by the crack initiation, propagation and coalescence formed from their natural voids and gaps, the effect of these voids and gaps over failure behavior of rocks should be investigated. Intact rocks are generally preferred due to relatively easy side of their homogeneous characteristics in numerical modelling phases. However, it is very hard to extract intact samples from vuggy rocks because of their complex pore sizes and distributions. In this study, the feasibility of concrete samples to model and mimic the failure behavior vuggy rocks was investigated. For this purpose, concrete samples were prepared at a mixture of %65 cement dust and %35 water and their physical and mechanical properties were determined by laboratory experiments. The obtained physical and mechanical properties were used to constitute numerical models, and then uniaxial compressive strength (UCS) tests were performed on these models by using a commercial software called as Particle Flow Code (PFC2D). When the crack behavior of concrete samples obtained from both laboratory tests and numerical models are compared with the results of previous studies, a significant similarity was found. As a result, due to the observed similarity crack behavior between concretes and rocks, it can be concluded that intact concrete samples can be used for modelling purposes to understand the effect of voids and gaps on failure characteristics of vuggy rocks.

Chemical composition of sedimentary rocks in California and Hawaii

USGS Publications Warehouse

Hill, Thelma P.

1981-01-01

A compilation of published chemical analyses of sedimentary rocks of the United States was undertaken by the U.S. Geological Survey in 1952 to make available scattered data that are needed for a wide range of economic and scientific uses. About 20,000-25,000 chemical analyses of sedimentary rocks in the United States have been published. This report brings together 2,312 of these analyses from California and Hawaii. The samples are arranged by general lithologic characteristics and locality. Indexes of stratigraphy, rock name, commercial uses, and minor elements are provided. The sedimentary rocks are classified into groups and into categories according to the chemical analyses. The groups (A through F2) are defined by a system similar to that proposed by Brian Mason in 1952, in which the main parameters are the three major components of sedimentary rocks: (1) uncombined silica, (2) clay (R203 ? 3Si02 ? nH20), and (3) calcium-magnesium carbonate. The categories are based on the degree of admixture of these three major components with other components, such as sulfate, phos- phate, and iron oxide. Common-rock, mixed-rock, and special-rock categories apply to rocks consisting of 85 percent or more, 50-84 percent, and less than 49 percent, respectively, of the three major components combined. Maps show distribution of sample localities by States; triangular diagrams show the lithologic characteristics and classification groups. Cumulative-frequency curves of each constituent in each classification group of the common-rock and mixed-rock categories are also included. The numerous analyses may not adequately represent the geochemical nature of the rock types and formations of the region because of sampling bias. Maps showing distribution of sample localities indicate that many of the localities are in areas where, for economic or other reasons, special problems attracted interest. Most of the analyzed rocks tended to be fairly simple in composition - mainly mixtures of just two of the three major components or a mixture of these and a fourth component such as phosphate, gypsum, or iron oxide.

Catalog of Apollo 17 rocks. Volume 1: Stations 2 and 3 (South Massif)

NASA Technical Reports Server (NTRS)

Ryder, Graham

1993-01-01

The Catalog of Apollo 17 Rocks is a set of volumes that characterize each of 334 individually numbered rock samples (79 larger than 100 g) in the Apollo 17 collection, showing what each sample is and what is known about it. Unconsolidated regolith samples are not included. The catalog is intended to be used by both researchers requiring sample allocations and a broad audience interested in Apollo 17 rocks. The volumes are arranged geographically, with separate volumes for the South Massif and Light Mantle, the North Massif, and two volumes for the mare plains. Within each volume, the samples are arranged in numerical order, closely corresponding with the sample collection stations. The present volume, for the South Massif and Light Mantle, describes the 55 individual rock fragments collected at Stations two, two-A, three, and LRV-five. Some were chipped from boulders, others collected as individual rocks, some by raking, and a few by picking from the soil in the processing laboratory. Information on sample collection, petrography, chemistry, stable and radiogenic isotopes, rock surface characteristics, physical properties, and curatorial processing is summarized and referenced as far as it is known up to early 1992. The intention has been to be comprehensive: to include all published studies of any kind that provide information on the sample, as well as some unpublished information. References which are primarily bulk interpretations of existing data or mere lists of samples are not generally included. Foreign language journals were not scrutinized, but little data appears to have been published only in such journals. We have attempted to be consistent in format across all of the volumes, and have used a common reference list that appears in all volumes. Where possible, ages based on Sr and Ar isotopes have been recalculated using the 'new' decay constants recommended by Steiger and Jager; however, in many of the reproduced diagrams the ages correspond with the 'old' decay constants. In this volume, mg' or Mg' = atomic Mg/(Mg +Fe).

Seabed Geoacoustic Planning Support for the QPE Uncertainty DRI

DTIC Science & Technology

2007-09-30

40% CaCO3 from planktonic foraminfera and pteropod shells associated with upwelling. • Rock fragments are common and abundant constituents of...variable over seasonal time scales. • On outer shelf and slope, presence of deep thermogenic methane leads to mud volcanoes (5-40 m in height; radii ~20

15. A DETAIL VIEW, LOOKING WEST FROM THE SOUTHEAST BANK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. A DETAIL VIEW, LOOKING WEST FROM THE SOUTHEAST BANK OF THE DITCH, SHOWING THE EAST SIDE OF ONE OF THE ABUTMENTS. MOST JOINTS LOOK DRY, BUT WERE ORIGINALLY FILLED WITH MORTAR. - Wells County Bridge No. 74, Spanning Rock Creek Ditch at County Road 400, Bluffton, Wells County, IN

Microwave dielectric spectrum of rocks

NASA Technical Reports Server (NTRS)

Ulaby, F. T.; Bengal, T.; East, J.; Dobson, M. C.; Garvin, J.; Evans, D.

1988-01-01

A combination of several measurement techniques was used to investigate the dielectric properties of 80 rock samples in the microwave region. The real part of the dielectric constant, epsilon', was measured in 0.1 GHz steps from 0.5 to 18 GHz, and the imaginary part, epsilon'', was measured at five frequencies extending between 1.6 and 16 GHz. In addition to the dielectric measurements, the bulk density was measured for all the samples and the bulk chemical composition was determined for 56 of the samples. The study shows that epsilon' is frequency-dependent over the 0.5 to 18 GHz range for all rock samples, and that the bulk density rho accounts for about 50 percent of the observed variance of epsilon'. For individual rock types (by genesis), about 90 percent of the observed variance may be explained by the combination of density and the fractional contents of SiO2, Fe2O3, MgO, and TiO2. For the loss factor epsilon'', it was not possible to establish statistically significant relationships between it and the measured properties of the rock samples (density and chemical composition).

Acid rock drainage and climate change

USGS Publications Warehouse

Nordstrom, D. Kirk

2009-01-01

Rainfall events cause both increases and decreases in acid and metals concentrations and their loadings from mine wastes, and unmined mineralized areas, into receiving streams based on data from 3 mines sites in the United States and other sites outside the US. Gradual increases in concentrations occur during long dry spells and sudden large increases are observed during the rising limb of the discharge following dry spells (first flush). By the time the discharge peak has occurred, concentrations are usually decreased, often to levels below those of pre-storm conditions and then they slowly rise again during the next dry spell. These dynamic changes in concentrations and loadings are related to the dissolution of soluble salts and the flushing out of waters that were concentrated by evaporation. The underlying processes, pyrite oxidation and host rock dissolution, do not end until the pyrite is fully weathered, which can take hundreds to thousands of years. These observations can be generalized to predict future conditions caused by droughts related to El Ni??o and climate change associated with global warming. Already, the time period for dry summers is lengthening in the western US and rainstorms are further apart and more intense when they happen. Consequently, flushing of inactive or active mine sites and mineralized but unmined sites will cause larger sudden increases in concentrations that will be an ever increasing danger to aquatic life with climate change. Higher average concentrations will be observed during longer low-flow periods. Remediation efforts will have to increase the capacity of engineered designs to deal with more extreme conditions, not average conditions of previous years.

Water quality and ecological condition of urban streams in Independence, Missouri, June 2005 through December 2008

USGS Publications Warehouse

Christensen, D.; Harris, Thomas E.; Niesen, Shelley L.

2010-01-01

To identify the sources of selected constituents in urban streams and better understand processes affecting water quality and their effects on the ecological condition of urban streams and the Little Blue River in Independence, Missouri the U.S. Geological Survey in cooperation with the City of Independence Water Pollution Control Department initiated a study in June 2005 to characterize water quality and evaluate the ecological condition of streams within Independence. Base-flow and stormflow samples collected from five sites within Independence, from June 2005 to December 2008, were used to characterize the physical, chemical, and biologic effects of storm runoff on the water quality in Independence streams and the Little Blue River. The streams draining Independence-Rock Creek, Sugar Creek, Mill Creek, Fire Prairie Creek, and the Little Blue River-drain to the north and the Missouri River. Two small predominantly urban streams, Crackerneck Creek [12.9-square kilometer (km2) basin] and Spring Branch Creek (25.4-km2 basin), were monitored that enter into the Little Blue River between upstream and downstream monitoring sites. The Little Blue River above the upstream site is regulated by several reservoirs, but streamflow is largely uncontrolled. The Little Blue River Basin encompasses 585 km2 with about 168 km2 or 29 percent of the basin lying within the city limits of Independence. Water-quality samples also were collected for Rock Creek (24.1-km2 basin) that drains the western part of Independence. Data collection included streamflow, physical properties, dissolved oxygen, chloride, metals, nutrients, common organic micro-constituents, and fecal indicator bacteria. Benthic macroinvertebrate community surveys and habitat assessments were conducted to establish a baseline for evaluating the ecological condition and health of streams within Independence. Additional dry-weather screenings during base flow of all streams draining Independence were conducted to identify point-source discharges and other sources of potential contamination. Regression models were used to estimate continuous and annual flow-weighted concentrations, loadings, and yields for chloride, total nitrogen, total phosphorus, suspended sediment, and Escherichia coli bacteria densities. Base-flow and stormflow water-quality samples were collected at five sites within Independence. Base-flow samples for Rock Creek and two tributary streams to the Little Blue River exceeded recommended U.S. Environmental Protection Agency standards for the protection of aquatic life for total nitrogen and total phosphorus in about 90 percent of samples, whereas samples collected at two Little Blue River sites exceeded both the total nitrogen and total phosphorus standards less often, about 30 percent of the time. Dry-weather screening identified a relatively small number (14.0 percent of all analyses) of potential point-source discharges for total chlorine, phenols, and anionic surfactants. Stormflow had larger median measured concentrations of total common organic micro-constituents than base flow. The four categories of common organic micro-constituents with the most total detections in stormflow were pesticides (100 percent), polyaromatic hydrocarbons and combustion by-products (99 percent), plastics (93 percent), and stimulants (91 percent). Most detections of common organic micro-constituents were less than 2 micrograms per liter. Median instantaneous Escherichia coli densities for stormflow samples showed a 21 percent increase measured at the downstream site on the Little Blue River from the sampled upstream site. Using microbial source-tracking methods, less than 30 percent of Escherichia coli bacteria in samples were identified as having human sources. Base-flow and stormflow data were used to develop regression equations with streamflow and continuous water-quality data to estimate daily concentrations, loads, and yields of various water-quality contaminants.

Effect of mineral phosphates on growth and nitrogen fixation of diazotrophic cyanobacteria Anabaena variabilis and Westiellopsis prolifica.

PubMed

Yandigeri, Mahesh S; Yadav, Arvind K; Meena, Kamlesh Kumar; Pabbi, Sunil

2010-03-01

The nitrogen fixing cyanobacterial strains namely Anabaena variabilis (Nostocales, Nostocaceae) and Westiellopsis prolifica (Nostocales, Hapalosiphonaceae) were evaluated for their nitrogen fixation and growth potential in response to different concentrations (10, 20 and 30 mg P) of the alternate insoluble P-sources Mussorie Rock Phosphate and Tricalcium Phosphate. Distinct and significant intergeneric differences were observed with respect to nitrogen fixation measured as Acetylene Reduction Activity (ARA) and growth potential as soluble proteins, total carbohydrate content, dry weight and total chlorophyll content in response to different concentrations of Mussorie Rock Phosphate and Tricalcium Phosphate. Both the strains showed higher soluble protein content at 20 mg P (Mussorie Rock Phosphate) that increased with time of incubation in A. variabilis. Both cyanobacteria recorded maximum Acetylene Reduction Activity at 20 mg P (Tricalcium Phosphate) followed by activity in presence of soluble phosphate (K2HPO4). The mean activity at all concentrations of insoluble phosphate (Mussorie Rock Phosphate and Tricalcium Phosphate) was more than in the presence of soluble phosphate.

MEPAG Recommendations for a 2018 Mars Sample Return Caching Lander - Sample Types, Number, and Sizes

NASA Technical Reports Server (NTRS)

Allen, Carlton C.

2011-01-01

The return to Earth of geological and atmospheric samples from the surface of Mars is among the highest priority objectives of planetary science. The MEPAG Mars Sample Return (MSR) End-to-End International Science Analysis Group (MEPAG E2E-iSAG) was chartered to propose scientific objectives and priorities for returned sample science, and to map out the implications of these priorities, including for the proposed joint ESA-NASA 2018 mission that would be tasked with the crucial job of collecting and caching the samples. The E2E-iSAG identified four overarching scientific aims that relate to understanding: (A) the potential for life and its pre-biotic context, (B) the geologic processes that have affected the martian surface, (C) planetary evolution of Mars and its atmosphere, (D) potential for future human exploration. The types of samples deemed most likely to achieve the science objectives are, in priority order: (1A). Subaqueous or hydrothermal sediments (1B). Hydrothermally altered rocks or low temperature fluid-altered rocks (equal priority) (2). Unaltered igneous rocks (3). Regolith, including airfall dust (4). Present-day atmosphere and samples of sedimentary-igneous rocks containing ancient trapped atmosphere Collection of geologically well-characterized sample suites would add considerable value to interpretations of all collected rocks. To achieve this, the total number of rock samples should be about 30-40. In order to evaluate the size of individual samples required to meet the science objectives, the E2E-iSAG reviewed the analytical methods that would likely be applied to the returned samples by preliminary examination teams, for planetary protection (i.e., life detection, biohazard assessment) and, after distribution, by individual investigators. It was concluded that sample size should be sufficient to perform all high-priority analyses in triplicate. In keeping with long-established curatorial practice of extraterrestrial material, at least 40% by mass of each sample should be preserved to support future scientific investigations. Samples of 15-16 grams are considered optimal. The total mass of returned rocks, soils, blanks and standards should be approximately 500 grams. Atmospheric gas samples should be the equivalent of 50 cubic cm at 20 times Mars ambient atmospheric pressure.

Geologic reconnaissance and geochemical sampling survey of molybdenum mineralization near Schiestler Peak, Temple Peak Quadrangle, Sublette County, Wyoming

USGS Publications Warehouse

Lee, G.K.; Antweiler, J.C.; Love, J.D.; Benedict, J.F.

1982-01-01

A brief geologic reconnaissance and geochemical survey of molybdenum mineralization near Schiestler Peak, Sublette County, Wyo., indicates that molybdenite occurs in this area as disseminations and blebs in granitic or quartz monzonitic rocks intruded by felsic dikes of similar composition. Samples of stream sediments, panned concentrates from stream sediments, soils, rocks, and water were collected in the geochemical survey. Analytical results show that in reconnaissance, panned concentrates are the best of the sample types used in this study to detect molybdenum mineralization. More detailed analysis of the distribution of the molybdenum is best achieved through the collection of rock samples. Hydrothermal alteration is generally not conspicuous in the study area; however, rock samples that contain molybdenite are usually slightly enriched in silver, copper, lead, and in several instances, gold. Conversely, there appear to be negative associations between molybdenum and zinc and between molybdenum and several of the rare-earth elements. Mo concentrations in the rock samples with no visible molybdenite range from undetectable at a sensitivity of 5 parts per million (ppm) to 700 ppm. Mo content in rock samples containing visible molybdenite ranges from 10 ppm to greater than 2,000 ppm. Stream-sediment values range from undetected to 15 ppm; panned concentrates from undetected to 15 ppm; soils from undetected to 20 ppm. Analyses of the water samples indicate Mo concentrations from 0.8 parts per billion (ppb) to 4.8 ppb. As currently understood, this deposit is not extensive or continuous, but drilling to provide information on the vertical extent of mineralization may alter this opinion.

Effects of yeast, fermentation time, and preservation methods on tarhana.

PubMed

Gurbuz, Ozan; Gocmen, Duygu; Ozmen, Nese; Dagdelen, Fatih

2010-01-01

The physicochemical properties of tarhana soup produced with different dough treatments, fermentation times, and preservation methods were examined. Tarhana doughs were prepared with yogurt (control) or baker's yeast (Saccharomyces cerevisiae) and fermented for 3 days. Samples were taken at 24, 48, and 72 hr. Samples were then preserved via one of four methods: sun dried, dried in the shade, vacumn dried, and frozen. Frozen samples produced lower organic acid levels after 72 hr of fermentation in both control (0.68 g/100 g) and yeast (0.61 g/100 g) applications than samples that were dried (0.94 g/100 g control samples; 0.81 g/100 g samples with yeast). Increasing fermentation time resulted in a significant effect on the formation of organic acid in the tarhana (p < .01). At 72 hr of fermentation, total acidity increased 11%, 17%, and 23% for tarhana samples vacumn-dried, sun-dried, and dried in the shade, respectively. Preservation methods also affected the moisture, ash, crude protein, total acidity, pH, salt, fat, reducing sugar levels, and the sensory assestment of tarhana soup (p < .01). Sensory characteristics were not significantly affected by baker's yeast in any of the preservation methods used (p > .01). However, sensory scores for tarhana prepared from the samples dried in a sheltered area showed a reduction in color desireablilty as the fermentation time increased. The soup prepared from frozen tarhana (72 hr fermentation, with yeast) had the highest scores with respect to color, mouth feel, flavor, and overall acceptability. Vacuum-dried samples' scores in these areas were also high in comparison to the two other drying methods.

'Mister Badger' Pushing Mars Rock

NASA Technical Reports Server (NTRS)

1976-01-01

Viking's soil sampler collector arm successfully pushed a rock on the surface of Mars during the afternoon of Friday, October 8. The irregular-shaped rock was pushed several inches by the Lander's collector arm, which displaced the rock to the left of its original position, leaving it cocked slightly upward. Photographs and other information verified the successful rock push. Photo at left shows the soil sampler's collector head pushing against the rock, named 'Mister Badger' by flight controllers. Photo at right shows the displaced rock and the depression whence it came. Part of the soil displacement was caused by the collector s backhoe. A soil sample will be taken from the site Monday night, October 11. It will then be delivered to Viking s organic chemistry instrument for a series of analyses during the next few weeks. The sample is being sought from beneath a rock because scientists believe that, if there are life forms on Mars, they may seek rocks as shelter from the Sun s intense ultraviolet radiation.

Phosphine from rocks: mechanically driven phosphate reduction?

PubMed

Glindemann, Dietmar; Edwards, Marc; Morgenstern, Peter

2005-11-01

Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks.

Specifics of the methodological approach to the study of nanoparticle impact on human health in the production of non-metallic nanomaterials for construction purposes

NASA Astrophysics Data System (ADS)

Ayzenshtadt, A. M.; Frolova, M. A.; Makhova, T. A.; Danilov, V. E.; Gupta, Piyush K.; Verma, Rama S.

2018-01-01

Minerals samples of mixed-genesis rocks in a finely dispersed state were obtained and studied, namely sand deposit (Kholmogory district) and basalt (Myandukha deposit, Plesetsk district) in Arkhangelsk region. The paper provides the chemical composition data used to calculate the specific mass atomization energy of rocks. The energy parameters of the micro and nano systems of the rock samples - free surface energy and surface activity - were calculated. For toxicological evaluation of the materials obtained, next-generation sequencing (NGS) was used to perform metagenomic analysis which allowed determining the species diversity of microorganisms in the samples under study. It was shown that the sequencing method and metagenomic analysis are applicable and provide good reproducibility for the analysis of the toxicological properties of selected rock samples. The correlation of the surface activity of finely dispersed rock systems and the species diversity of cultivated microorganisms on the raw material was observed.

The forensiX evidence collection tube and its impact on DNA preservation and recovery.

PubMed

Garvin, Alex M; Holzinger, Ralf; Berner, Florian; Krebs, Walter; Hostettler, Bernhard; Lardi, Elges; Hertli, Christian; Quartermaine, Roy; Stamm, Christoph

2013-01-01

Biological samples are vulnerable to degradation from the time they are collected until they are analysed at the laboratory. Biological contaminants, such as bacteria, fungi, and enzymes, as well as environmental factors, such as sunlight, heat, and humidity, can increase the rate of DNA degradation. Currently, DNA samples are normally dried or frozen to limit their degradation prior to their arrival at the laboratory. In this study, the effect of the sample drying rate on DNA preservation was investigated, as well as a comparison between drying and freezing methods. The drying performances of two commercially available DNA collection tools (swab and drying tube) with different drying rates were evaluated. The swabs were used to collect human saliva, placed into the drying tubes, and stored in a controlled environment at 25°C and 60% relative humidity, or frozen at -20°C, for 2 weeks. Swabs that were stored in fast sample drying tubes yielded 95% recoverable DNA, whereas swabs stored in tubes with slower sample drying rates yielded only 12% recoverable DNA; saliva stored in a microtube at -20°C was used as a control. Thus, DNA sampling tools that offer rapid drying can significantly improve the preservation of DNA collected on a swab, increasing the quantity of DNA available for subsequent analysis.

Eclogitization of dry granulite triggers deep crustal seismicity in Southern Tibet

NASA Astrophysics Data System (ADS)

Shi, Feng; Wang, Yanbin; Yu, Tony; Zhu, Lupei; Gasc, Julien; Zhang, Junfeng; Jin, Zhenmin

2017-04-01

Intermediate-depth earthquakes (IDEQs) occur at focal depths from about 50 km to 300 km. Their physical mechanism has been enigmatic, because as pressure and temperature increase with depth, brittle failure should be suppressed, and rocks tend to flow plastically. IDEQs have been recorded down to depths of 80 - 100 km in Southern Tibet, where the lower crust is considered hot and dry [1]. It is questionable whether such seismicity can be produced by unassisted brittle shear fracture or frictional sliding. Pseudotachylytes that formed under conditions corresponding to the eclogitic facies are ubiquitously observed in western Norway [2], demonstrating that faulting took place in granulite, which is the main constituent of lower continental crust at pressures approaching 3 GPa. These observations suggest strongly that eclogitization is potentially involved in the seismicity in the deep continental crust. Here we conduct deformation experiments on natural and nominally dry granulite in a deformation-DIA (DDIA) apparatus and Griggs apparatus within the thermal stability fields of both granulite and eclogite, to investigate the mechanism of intermediate earthquake. The D-DIA, installed at the synchrotron beamline of GSECARS, is interfaced with an acoustic emission (AE) monitoring system, allowing in-situ detection of mechanical instability along with the progress of eclogitization based on x-ray diffraction. We found that granulite deformed within its own stability field (< 2 GPa and 1000°C) behaved in a ductile fashion without any AE activity. Unstable fault slip, on the other hand, occurred during deformation of metastable granulite in the eclogite field above 2 GPa. Numerous AE events were observed. Microstructural observation on recovered samples shows conjugated macroscopic faults. Strain is highly localized along the fault, and microcracks observed along grain boundary likely involve with eclogitization products. The fault zones consist of fine- grained (<< 1 μm) angular fragments likely to be eclogitic phase transformation products. However, no pseudotachylyte has been found in these samples so far. Therefore, we conclude that eclogitization of deforming metastable dry granulite can produce mechanical instability. No formation of pseudotachylytes is required for brittle failure. We suggest that syn-deformational eclogitization of dry granulite may be responsible to the lower crustal seismicity in Southern Tibet. References [1] Hacker, B, et al., Science, 287, 2463-2466 (2000). [2] Austrheim, H. & Boundy, T. M. Science 265, 82-83 (1994).

Origin of middle rare earth element enrichments in acid waters of a Canadian high Arctic lake.

NASA Astrophysics Data System (ADS)

Johannesson, Kevin H.; Zhou, Xiaoping

1999-01-01

-Middle rare earth element (MREE) enriched rock-normalized rare earth element (REE) patterns of a dilute acidic lake (Colour Lake) in the Canadian High Arctic, were investigated by quantifying whole-rock REE concentrations of rock samples collected from the catchment basin, as well as determining the acid leachable REE fraction of these rocks. An aliquot of each rock sample was leached with 1 N HNO 3 to examine the readily leachable REE fraction of each rock, and an additional aliquot was leached with a 0.04 M NH 2OH · HCl in 25% (v/v) CH 3COOH solution, designed specifically to reduce Fe-Mn oxides/oxyhydroxides. Rare earth elements associated with the leachates that reacted with clastic sedimentary rock samples containing petrographically identifiable Fe-Mn oxide/oxyhydroxide cements and/or minerals/amorphous phases, exhibited whole-rock-normalized REE patterns similar to the lake waters, whereas whole-rock-normalized leachates from mafic igneous rocks and other clastic sedimentary rocks from the catchment basin differed substantially from the lake waters. The whole-rock, leachates, and lake water REE data support acid leaching or dissolution of MREE enriched Fe-Mn oxides/oxyhydroxides contained and identified within some of the catchment basin sedimentary rocks as the likely source of the unique lake water REE patterns. Solution complexation modelling of the REEs in the inflow streams and lake waters indicate that free metal ions (e.g., Ln 3+, where Ln = any REE) and sulfate complexes (LnSO 4+) are the dominant forms of dissolved REEs. Consequently, solution complexation reactions involving the REEs during weathering, transport to the lake, or within the lake, cannot be invoked to explain the MREE enrichments observed in the lake waters.

Semimicro chemical and x-ray fluorescence analysis of lunar samples

USGS Publications Warehouse

Rose, H.J.; Cuttitta, F.; Dwornik, E.J.; Carron, M.K.; Christian, R.P.; Lindsay, J.R.; Ligon, D.T.; Larson, R.R.

1970-01-01

Major and selected minor elements were determined in seven whole rock fragments, five portions of pulverized lunar rock, and the lunar soil. Three different rock types were represented: vesicular, fine-grained basaltic rocks; medium-to coarse-grained, vuggy gabbroic rocks; and breccia. The ranges (in percent) for the major constituents of the lunar samples are: SiO2, 38 to 42; Al2O3, 8 to 14; total iron as FeO, 15 to 20; MgO, 6 to 8; CaO, 10 to 12; Na2O, 0.5 to 1; K2O, 0.05 to 0.4; TiO2, 8 to 13; MnO, 0.2 to 0.3; and Cr2O3, 0.2 to 0.4. The high reducing capacity of the samples strongly suggests the presence of Ti(III).

Evolution of strength and physical properties of carbonate and ultramafic rocks under hydrothermal conditions

NASA Astrophysics Data System (ADS)

Lisabeth, Harrison Paul

Interaction of rocks with fluids can significantly change mineral assemblage and structure. This so-called hydrothermal alteration is ubiquitous in the Earth's crust. Though the behavior of hydrothermally altered rocks can have planet-scale consequences, such as facilitating oceanic spreading along slow ridge segments and recycling volatiles into the mantle at subduction zones, the mechanisms involved in the hydrothermal alteration are often microscopic. Fluid-rock interactions take place where the fluid and rock meet. Fluid distribution, flux rate and reactive surface area control the efficiency and extent of hydrothermal alteration. Fluid-rock interactions, such as dissolution, precipitation and fluid mediated fracture and frictional sliding lead to changes in porosity and pore structure that feed back into the hydraulic and mechanical behavior of the bulk rock. Examining the nature of this highly coupled system involves coordinating observations of the mineralogy and structure of naturally altered rocks and laboratory investigation of the fine scale mechanisms of transformation under controlled conditions. In this study, I focus on fluid-rock interactions involving two common lithologies, carbonates and ultramafics, in order to elucidate the coupling between mechanical, hydraulic and chemical processes in these rocks. I perform constant strain-rate triaxial deformation and constant-stress creep tests on several suites of samples while monitoring the evolution of sample strain, permeability and physical properties. Subsequent microstructures are analyzed using optical and scanning electron microscopy. This work yields laboratory-based constraints on the extent and mechanisms of water weakening in carbonates and carbonation reactions in ultramafic rocks. I find that inundation with pore fluid thereby reducing permeability. This effect is sensitive to pore fluid saturation with respect to calcium carbonate. Fluid inundation weakens dunites as well. The addition of carbon dioxide to pore fluid enhances compaction and partial recovery of strength compared to pure water samples. Enhanced compaction in CO2-rich fluid samples is not accompanied by enhanced permeability reduction. Analysis of sample microstructures indicates that precipitation of carbonates along fracture surfaces is responsible for the partial restrengthening and channelized dissolution of olivine is responsible for permeability maintenance.

Apollo rocks, fines and soil cores

NASA Astrophysics Data System (ADS)

Allton, J.; Bevill, T.

Apollo rocks and soils not only established basic lunar properties and ground truth for global remote sensing, they also provided important lessons for planetary protection (Adv. Space Res ., 1998, v. 22, no. 3 pp. 373-382). The six Apollo missions returned 2196 samples weighing 381.7 kg, comprised of rocks, fines, soil cores and 2 gas samples. By examining which samples were allocated for scientific investigations, information was obtained on usefulness of sampling strategy, sampling devices and containers, sample types and diversity, and on size of sample needed by various disciplines. Diversity was increased by using rakes to gather small rocks on the Moon and by removing fragments >1 mm from soils by sieving in the laboratory. Breccias and soil cores are diverse internally. Per unit weight these samples were more often allocated for research. Apollo investigators became adept at wringing information from very small sample sizes. By pushing the analytical limits, the main concern was adequate size for representative sampling. Typical allocations for trace element analyses were 750 mg for rocks, 300 mg for fines and 70 mg for core subsamples. Age-dating and isotope systematics allocations were typically 1 g for rocks and fines, but only 10% of that amount for core depth subsamples. Historically, allocations for organics and microbiology were 4 g (10% for cores). Modern allocations for biomarker detection are 100mg. Other disciplines supported have been cosmogenic nuclides, rock and soil petrology, sedimentary volatiles, reflectance, magnetics, and biohazard studies . Highly applicable to future sample return missions was the Apollo experience with organic contamination, estimated to be from 1 to 5 ng/g sample for Apollo 11 (Simonheit &Flory, 1970; Apollo 11, 12 &13 Organic contamination Monitoring History, U.C. Berkeley; Burlingame et al., 1970, Apollo 11 LSC , pp. 1779-1792). Eleven sources of contaminants, of which 7 are applicable to robotic missions, were identified and reduced; thus, improving Apollo 12 samples to 0.1 ng/g. Apollo sample documentation preserves the parentage, orientation, and location, packaging, handling and environmental histories of each of the 90,000 subsamples currently curated. Active research on Apollo samples continues today, and because 80% by weight of the Apollo collection remains pristine, researchers have a reservoir of material to support studies well into the future.

Risks to human health and estuarine ecology posed by pulling out creosote-treated timber on oyster farms.

PubMed

Smith, Paul T

2008-01-31

Five oyster farms in Port Stephens, Australia were studied to identify consequences of using creosote-treated posts and the risks posed by removing the posts. Gas chromatography coupled with mass spectrometry (GC/MS) was used to measure polycyclic aromatic hydrocarbons (PAHs) and phenols in sediments, timber, water and oyster tissue. Before posts were removed, the total PAHs in surface sediment on farms was 24.1 mgkg(-1) dry weight. This increased to 45.5 mgkg(-1) dry weight after the posts were pulled out and remained significantly higher 6 months later at 59.7 mgkg(-1) dry weight. A similar increase was found in deeper sediments. The sediment attached to creosote-treated posts had a total concentration of PAHs of 484-2642 mgkg(-1) dry weight, while the corresponding value for the sediment on tar-treated posts was only 30.7 mgkg(-1) dry weight. The surface timber of creosote-treated posts had high levels of PAHs and an average post contained 43 g of PAHs. The total PAHs dispersed to the environment when a creosote-treated post was pulled out was at least 0.67 g. The main species were PAHs with low-molecular weights: fluoranthene, phenanthrene, pyrene, acenaphthylene and chrysene. Benzo(a)pyrene represented 1-10% of PAHs in most samples. Bioassays with creosote-contaminated sediment revealed that Sydney rock oysters (Saccostrea glomerate) and Pacific oysters (Crassostrea gigas) accumulated PAHs at (mgkg(-1) wet tissue weight): 11.3-15.3 and 35.5-47.9, respectively, when exposed for 5 days to water with < 1 microgl(-1) PAHs. Wild oysters growing on creosote-treated posts had high levels of phenols (0.09-6.92 mgkg(-1) wet weight) and PAHs (0.59-1.01 mgkg(-1) wet weight). The dilemma posed by removing creosote-treated posts and dispersing carcinogenic, bioavailable contaminants needs to be managed in light of risks to human health and estuarine ecology.

Quantitative analysis of major and trace elements in NH4HF2-modified silicate rock powders by laser ablation - inductively coupled plasma mass spectrometry.

PubMed

Zhang, Wen; Hu, Zhaochu; Liu, Yongsheng; Yang, Wenwu; Chen, Haihong; Hu, Shenghong; Xiao, Hongyan

2017-08-29

In this paper, we described a NH 4 HF 2 digestion method as sample preparation for the rapid determination of major and trace elements in silicate rocks using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Sample powders digested by NH 4 HF 2 at 230 °C for 3 h form ultrafine powders with a typical grain size d 80  < 8.5 μm, and various silicate rocks have a consistent grain morphology and size, allowing us to produce pressed powder pellets that have excellent cohesion and homogeneity suitable for laser ablation micro-analysis without the addition of binder. The influences of the digestion parameters were investigated and optimized, including the evaporation stage of removing residual NH 4 HF 2 , sample homogenization, selection of the digestion vessel and calibration strategy of quantitative analysis. The optimized NH 4 HF 2 digestion method was applied to dissolve six silicate rock reference materials (BCR-2, BHVO-2, AGV-2, RGM-2, GSP-2, GSR-1) covering a wide range of rock types. Ten major elements and thirty-five trace elements were simultaneously analyzed by LA-ICP-MS. The analytical results of the six reference materials generally agreed with the recommended values, with discrepancies of less than 10% for most elements. The analytical precision is within 5% for most major elements and within 10% for most trace elements. Compared with previous methods of LA-ICP-MS bulk analysis, our method enables the complete dissolution of refractory minerals, such as zircon, in intermediate-acidic intrusive rocks and limits contamination as well as the loss of volatile elements. Moreover, there are many advantages for the new technique, including reducing matrix effects between reference materials and samples, spiking the internal standard simply and feasibly and sample batch processing. The applicability filed of the new technique in this study was focused on the whole-rock analysis of igneous rock samples, which are from basic rocks to acid rocks (45% < SiO 2  < 73%). However, we thought that the NH 4 HF 2 digestion method can be used as a new alternative in LA-ICP-MS for a wider range of geological samples, and will significantly accelerate the application of LA-ICP-MS for the whole-rock analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluid flow and permeabilities in basement fault zones

NASA Astrophysics Data System (ADS)

Hollinsworth, Allan; Koehn, Daniel

2017-04-01

Fault zones are important sites for crustal fluid flow, specifically where they cross-cut low permeability host rocks such as granites and gneisses. Fluids migrating through fault zones can cause rheology changes, mineral precipitation and pore space closure, and may alter the physical and chemical properties of the host rock and deformation products. It is therefore essential to consider the evolution of permeability in fault zones at a range of pressure-temperature conditions to understand fluid migration throughout a fault's history, and how fluid-rock interaction modifies permeability and rheological characteristics. Field localities in the Rwenzori Mountains, western Uganda and the Outer Hebrides, north-west Scotland, have been selected for field work and sample collection. Here Archaean-age TTG gneisses have been faulted within the upper 15km of the crust and have experienced fluid ingress. The Rwenzori Mountains are an anomalously uplifted horst-block located in a transfer zone in the western rift of the East African Rift System. The north-western ridge is characterised by a tectonically simple western flank, where the partially mineralised Bwamba Fault has detached from the Congo craton. Mineralisation is associated with hydrothermal fluids heated by a thermal body beneath the Semliki rift, and has resulted in substantial iron oxide precipitation within porous cataclasites. Non-mineralised faults further north contain foliated gouges and show evidence of leaking fluids. These faults serve as an analogue for faults associated with the Lake Albert oil and gas prospects. The Outer Hebrides Fault Zone (OHFZ) was largely active during the Caledonian Orogeny (ca. 430-400 Ma) at a deeper crustal level than the Ugandan rift faults. Initial dry conditions were followed by fluid ingress during deformation that controlled its rheological behaviour. The transition also altered the existing permeability. The OHFZ is a natural laboratory in which to study brittle fault rocks, and younger Mesozoic age faults may provide analogues for the West Shetland basin. Samples have been collected from both of these localities, and will be examined by optical and scanning electron microscopy. X-Ray micro-tomography will also be used to analyse the permeability characteristics of the fault rocks. Our understanding of fault zone permeability is crucial for a number of research areas, including earthquake geoscience, economic mineral formation, and hydrocarbon systems. As a result, this research has relevance to a variety of industry sectors, including oil and gas (and ccs), nuclear waste disposal, geothermal and mining.

Drilling and Caching Architecture for the Mars2020 Mission

NASA Astrophysics Data System (ADS)

Zacny, K.

2013-12-01

We present a Sample Acquisition and Caching (SAC) architecture for the Mars2020 mission and detail how the architecture meets the sampling requirements described in the Mars2020 Science Definition Team (SDT) report. The architecture uses 'One Bit per Core' approach. Having dedicated bit for each rock core allows a reduction in the number of core transfer steps and actuators and this reduces overall mission risk. It also alleviates the bit life problem, eliminates cross contamination, and aids in hermetic sealing. An added advantage is faster drilling time, lower power, lower energy, and lower Weight on Bit (which reduces Arm preload requirements). To enable replacing of core samples, the drill bits are based on the BigTooth bit design. The BigTooth bit cuts a core diameter slightly smaller than the imaginary hole inscribed by the inner surfaces of the bits. Hence the rock core could be much easier ejected along the gravity vector. The architecture also has three additional types of bits that allow analysis of rocks. Rock Abrasion and Brushing Bit (RABBit) allows brushing and grinding of rocks in the same was as Rock Abrasion Tool does on MER. PreView bit allows viewing and analysis of rock core surfaces. Powder and Regolith Acquisition Bit (PRABit) captures regolith and rock powder either for in situ analysis or sample return. PRABit also allows sieving capabilities. The architecture can be viewed here: http://www.youtube.com/watch?v=_-hOO4-zDtE

Preliminary reconnaissance survey for thorium, uranium, and rare-earth oxides, Bear Lodge Mountains, Crook County, Wyoming

USGS Publications Warehouse

Wilmarth, V.R.; Johnson, D.H.

1953-01-01

An area about 6 miles north of Sundance, in the Bear Lodge Mountains, in Crook County, Wyo., was examined during August 1950 for thorium, uranium, and rare-earth oxides and samples were collected. Uranium is known to occur in fluorite veins and iron-manganese veins and in the igneous rocks of Tertiary age that compose the core of the Bear Lodge Mountains. The uranium content of the samples ranges from 0.001 to 0.015 percent in those from the fluorite veins, from 0.005 to 0.018 percent in those from the iron-manganese veins, and from 0.001 to 0.017 percent in those from the igneous rocks. The radioactivity of the samples is more than that expected from the uranium content. Thorium accounts for most of this discrepancy. The thorium oxide content of samples ranges from 0.07 to 0.25 percent in those from the iron-manganese veins and from 0.07 to 0.39 percent in those from the sedimentary rocks, and from0.04 to 0.30 in those from the igneous rocks. Rare-earth oxides occur in iron-manganese veins and in zones of altered igneous rocks. The veins contain from 0.16 to 12.99 percent rare-earth oxides, and the igneous rocks, except for two localities, contain from 0.01 to 0.42 percent rare-earth oxides. Inclusions of metamorphosed sedimentary rocks in the intrusive rocks contain from 0.07 to 2.01 percent rare-earth oxides.

Industrial applications of hot dry rock geothermal energy

NASA Astrophysics Data System (ADS)

Duchane, D. V.

1992-07-01

Geothermal resources in the form of naturally occurring hot water or steam have been utilized for many years. While these hydrothermal resources are found in many places, the general case is that the rock at depth is hot, but does not contain significant amounts of mobile fluid. An extremely large amount of geothermal energy is found around the world in this hot dry rock (HDR). Technology has been under development for more than twenty years at the Los Alamos National Laboratory in the United States and elsewhere to develop the technology to extract the geothermal energy from HDR in a form useful for electricity generation, space heating, or industrial processing. HDR technology is especially attractive for industrial applications because of the ubiquitous distribution of the HDR resource and the unique aspects of the process developed to recover it. In the HDR process, as developed at Los Alamos, water is pumped down a well under high pressure to open up natural joints in hot rock and create an artificial geothermal reservoir. Energy is extracted by circulating water through the reservoir. Pressurized hot water is returned to the surface through the production well, and its thermal energy is extracted for practical use. The same water is then recirculated through the system to mine more geothermal heat. Construction of a pilot HDR facility at Fenton Hill, NM, USA, has recently been completed by the Los Alamos National Laboratory. It consists of a large underground reservoir, a surface plant, and the connecting wellbores. This paper describes HDR technology and the current status of the development program. Novel industrial applications of geothermal energy based on the unique characteristics of the HDR energy extraction process are discussed.

Evaluation of kinetic uncertainty in numerical models of petroleum generation

USGS Publications Warehouse

Peters, K.E.; Walters, C.C.; Mankiewicz, P.J.

2006-01-01

Oil-prone marine petroleum source rocks contain type I or type II kerogen having Rock-Eval pyrolysis hydrogen indices greater than 600 or 300-600 mg hydrocarbon/g total organic carbon (HI, mg HC/g TOC), respectively. Samples from 29 marine source rocks worldwide that contain mainly type II kerogen (HI = 230-786 mg HC/g TOC) were subjected to open-system programmed pyrolysis to determine the activation energy distributions for petroleum generation. Assuming a burial heating rate of 1??C/m.y. for each measured activation energy distribution, the calculated average temperature for 50% fractional conversion of the kerogen in the samples to petroleum is approximately 136 ?? 7??C, but the range spans about 30??C (???121-151??C). Fifty-two outcrop samples of thermally immature Jurassic Oxford Clay Formation were collected from five locations in the United Kingdom to determine the variations of kinetic response for one source rock unit. The samples contain mainly type I or type II kerogens (HI = 230-774 mg HC/g TOC). At a heating rate of 1??C/m.y., the calculated temperatures for 50% fractional conversion of the Oxford Clay kerogens to petroleum differ by as much as 23??C (127-150??C). The data indicate that kerogen type, as defined by hydrogen index, is not systematically linked to kinetic response, and that default kinetics for the thermal decomposition of type I or type II kerogen can introduce unacceptable errors into numerical simulations. Furthermore, custom kinetics based on one or a few samples may be inadequate to account for variations in organofacies within a source rock. We propose three methods to evaluate the uncertainty contributed by kerogen kinetics to numerical simulations: (1) use the average kinetic distribution for multiple samples of source rock and the standard deviation for each activation energy in that distribution; (2) use source rock kinetics determined at several locations to describe different parts of the study area; and (3) use a weighted-average method that combines kinetics for samples from different locations in the source rock unit by giving the activation energy distribution for each sample a weight proportional to its Rock-Eval pyrolysis S2 yield (hydrocarbons generated by pyrolytic degradation of organic matter). Copyright ?? 2006. The American Association of Petroleum Geologists. All rights reserved.

Biological Communities in Desert Varnish and Potential Implications for Varnish Formation Mechanisms

NASA Astrophysics Data System (ADS)

Lang-Yona, Naama; Maier, Stefanie; Macholdt, Dorothea; Rodriguez-Caballero, Emilio; Müller-Germann, Isabell; Yordanova, Petya; Jochum, Klaus-Peter; Andreae, Meinrat O.; Pöschl, Ulrich; Weber, Bettina; Fröhlich-Nowoisky, Janine

2017-04-01

Desert varnishes are thin, orange to black coatings found on rocks in arid and semi-arid environments on Earth. The formation mechanisms of rock varnish are still under debate and the involvement of microorganisms in this process remains unclear. In this work we aimed to identify the microbial community occurring in rock varnish to potentially gain insights into the varnish formation mechanism. For this purpose, rocks coated with desert varnish were collected from the Anza-Borrego Desert, California, USA, as well as soils from underneath the rocks. DNA from both varnish coatings and soil samples was extracted and subsequently used for metagenomic analysis, as well as for q-PCR analyses for specific species quantification. The element composition of the varnish coatings was analyzed and compared to the soil samples. Rock varnish shows similar depleted elements, compared to soil, but Mn and Pb are 50-60 times enriched compared to the soil samples, and about 100 times enriched compared to the upper continental crust. Our genomic analyses suggest unique populations and different protein functional groups occurring in the varnish compared to soil samples. We discuss these differences and try to shed light on the mechanism of Mn oxyhydroxide production in desert varnish formation.

Geologic Map of the Warm Spring Canyon Area, Death Valley National Park, Inyo County, California, With a Discussion of the Regional Significance of the Stratigraphy and Structure

USGS Publications Warehouse

Wrucke, Chester T.; Stone, Paul; Stevens, Calvin H.

2007-01-01

Warm Spring Canyon is located in the southeastern part of the Panamint Range in east-central California, 54 km south of Death Valley National Park headquarters at Furnace Creek Ranch. For the relatively small size of the area mapped (57 km2), an unusual variety of Proterozoic and Phanerozoic rocks is present. The outcrop distribution of these rocks largely resulted from movement on the east-west-striking, south-directed Butte Valley Thrust Fault of Jurassic age. The upper plate of the thrust fault comprises a basement of Paleoproterozoic schist and gneiss overlain by a thick sequence of Mesoproterozoic and Neoproterozoic rocks, the latter of which includes diamictite generally considered to be of glacial origin. The lower plate is composed of Devonian to Permian marine formations overlain by Jurassic volcanic and sedimentary rocks. Late Jurassic or Early Cretaceous plutons intrude rocks of the area, and one pluton intrudes the Butte Valley Thrust Fault. Low-angle detachment faults of presumed Tertiary age underlie large masses of Neoproterozoic dolomite in parts of the area. Movement on these faults predated emplacement of middle Miocene volcanic rocks in deep, east-striking paleovalleys. Excellent exposures of all the rocks and structural features in the area result from sparse vegetation in the dry desert climate and from deep erosion along Warm Spring Canyon and its tributaries.

Changes in crack shape and saturation during water penetration into stressed rock

NASA Astrophysics Data System (ADS)

Masuda, K.; Nishizawa, O.

2012-12-01

Open cracks and cavities in rocks play important roles in fluid transport. Water penetration induced microcrack activities and caused the failure of rocks. Fluids in cracks affect earthquake generation mechanism through physical and physicochemical effects. Methods of characterizing crack shape and water saturation of rocks underground are needed for many scientific and industrial applications. It would be desirable to estimate the status of cracks using readily observable data such as elastic-wave velocities. We demonstrate a laboratory method for estimating crack status inside a cylindrical rock sample based on least-squares fitting of a cracked solid model to measured P- and S-wave velocities, and porosity derived from strain data. We used a cylinder (50 mm in diameter and 100 mm in length) of medium-grained granite. We applied a differential stress of 370 MPa, which corresponds to about 70% of fracture strength, to the rock sample under 30 MPa confining pressure and held it constant throughout the experiment. When the primary creep stage and acoustic emission (AE) caused by the initial loading had ceased, we injected distilled water into the bottom end of the sample at a constant pressure of 25 MPa until macroscopic fracture occurred. During water migration, we measured P waves and S waves (Sv and Sh), in five directions parallel to the top and bottom surfaces of the sample. We also measured strains of the sample surface and monitored AE. We created X-ray computer tomography (CT) images of the rock sample after the experiment in order to recognize the location and shape of fractured surfaces. We observed the different patterns of velocity changes in the upper and lower portions of the rock sample. Changes in P-wave velocities can be interpreted based on the crack density. S-waves showed the splitting with Vsv being faster than Vsh, corresponding to the second kind of anisotropy. We estimated two crack characteristics, crack shape and the degree of water saturation, and their changes during the loading and water migration into a granitic rock subjected to confining pressure and differential stress. We found that during injection of water to induce failure of a stressed rock sample, the aspect ratio of cracks increased and the degree of water saturation increased to about 70%. Laboratory derived method can be applicable for the well-planned observation in the field experiments. Monitoring in situ crack situations with seismic waves are useful for industrial and scientific applications such as sequestrations of carbon dioxide and waste, and measuring the regional stress field.

Stick slip, charge separation and decay

USGS Publications Warehouse

Lockner, D.A.; Byerlee, J.D.; Kuksenko, V.S.; Ponomarev, A.V.

1986-01-01

Measurements of charge separation in rock during stable and unstable deformation give unexpectedly large decay times of 50 sec. Time-domain induced polarization experiments on wet and dry rocks give similar decay times and suggest that the same decay mechanisms operate in the induced polarization response as in the relaxation of charge generated by mechanical deformation. These large decay times are attributed to electrochemical processes in the rocks, and they require low-frequency relative permittivity to be very large, in excess of 105. One consequence of large permittivity, and therefore long decay times, is that a significant portion of any electrical charge generated during an earthquake can persist for tens or hundreds of seconds. As a result, electrical disturbances associated with earthquakes should be observable for these lengths of time rather than for the milliseconds previously suggested. ?? 1986 Birka??user Verlag.

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

PubMed

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

2015-09-01

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

Detection of hepatitis B virus infection markers in dried plasma spots among patients in Congo-Brazzaville.

PubMed

Alidjinou, Enagnon Kazali; Moukassa, Donatien; Sané, Famara; Twagirimana Nyenyeli, Séraphin; Akoko, Estina Chandrelle; Mountou, Michèle Valy; Bocket, Laurence; Ibara, Jean-Rosaire; Hober, Didier

2014-03-01

The detection of hepatitis B virus (HBV) infection markers by using dried plasma spots from 32 patients living in Congo has been assessed. Considering frozen plasma samples as gold standard, the sensitivity and specificity of HBV serologic markers detection in dried plasma eluted from filter paper were 100%. The sensitivity and the specificity of HBV DNA detection reached 96% and 100%, respectively, with plasma samples dried on filter paper compared to standard samples. Dried plasma samples can represent an alternative to conventional sampling for HBV detection and management of the infection in developing countries. Copyright © 2014 Elsevier Inc. All rights reserved.

Melting behavior and phase relations of lunar samples. [Apollo 12 rock samples

NASA Technical Reports Server (NTRS)

Hays, J. F.

1975-01-01

Cooling rate studies of 12002 were conducted and the results interpreted in terms of the crystallization history of this rock and certain other picritic Apollo 12 samples. Calculations of liquid densities and viscosities during crystallization, crystal settling velocities, and heat loss by the parent rock body are discussed, as are petrographic studies of other Apollo 12 samples. The process of magmatic differentiation that must have accompanied the early melting and chemical fractionation of the moon's outer layers was investigated. The source of regions of both high- and low-titanium mare basalts were also studied.

The Geochemical Databases GEOROC and GeoReM - What's New?

NASA Astrophysics Data System (ADS)

Sarbas, B.; Jochum, K. P.; Nohl, U.; Weis, U.

2017-12-01

The geochemical databases GEOROC (http: georoc.mpch-mainz.gwdg.de) and GeoReM (http: georem.mpch-mainz.gwdg.de) are maintained by the Max Planck Institute for Chemistry in Mainz, Germany. Both online databases became crucial tools for geoscientists from different research areas. They are regularly upgraded by new tools and new data from recent publications obtained from a wide range of international journals. GEOROC is a collection of published analyses of volcanic rocks and mantle xenoliths. Since recently, data for plutonic rocks are added. The analyses include major and trace element concentrations, radiogenic and non-radiogenic isotope ratios as well as analytical ages for whole rocks, glasses, minerals and inclusions. Samples come from eleven geological settings and span the whole geological age scale from Archean to Recent. Metadata include, among others, geographic location, rock class and rock type, geological age, degree of alteration, analytical method, laboratory, and reference. The GEOROC web page allows selection of samples by geological setting, geography, chemical criteria, rock or sample name, and bibliographic criteria. In addition, it provides a large number of precompiled files for individual locations, minerals and rock classes. GeoReM is a database collecting information about reference materials of geological and environmental interest, such as rock powders, synthetic and natural glasses as well as mineral, isotopic, biological, river water and seawater reference materials. It contains published data and compilation values (major and trace element concentrations and mass fractions, radiogenic and stable isotope ratios). Metadata comprise, among others, uncertainty, analytical method and laboratory. Reference materials are important for calibration, method validation, quality control and to establish metrological traceability. GeoReM offers six different search strategies: samples or materials (published values), samples (GeoReM preferred values), chemical criteria, chemical criteria based on bibliography, bibliography, as well as methods and institutions.

Eco-monitoring of highly contaminated areas: historic heavy metal contamination in tree ring records

NASA Astrophysics Data System (ADS)

Baross, Norbert; Jordán, Győző; Albert, Julianna; Abdaal, Ahmed; Anton, Attila

2014-05-01

This study examines and compares tree rings of trees grown in a mining area highly contaminated with heavy metals. Tree rings offers an excellent opportunity for eco-monitoring polluted areas. Contamination dispersion from the source to the receptors can be studied in time and space. The sampled area is located in the eastern part of the Matra Mts. of the Inner-Carpathian calc-alkaline Volcanic Arc (Hungary) with abundant historical ore (Pb, Zn, Cu, etc.) mining in the area. Dense forests are composed of the most typical association of the Turkey oak (Quercus cerris). Scots pine (Pinus sylvestris), European black pine (Pinus nigra), oak (Quercus robur), beech (Fagus sylvatica), and hornbeam (Carpinus betulus) also occurs in the landscape. Sampled trees are located within a 1km radius of the abandoned historic ore mines. Sample sites were located above the old mines and waste rock heaps, under the waste rock heaps and on the floodplain of the Ilona Creek. The sampled trees were selected by the following criteria: the tree should be healthy, showing no signs of thunderbolt or diseases and having a minimum diameter of 50 cm. Samples were taken with a tree borer at the height of 150 cm. At the same time, soil samples were also taken near the trees in a 25 cm depth. Prior to laboratory analysis, the samples measured and air dried. Every fifth years tree ring was taken from the samples under microscope, working backwards from the most recent outer ring (2012, the year of the sampling). Samples were digested with a mixture of H2SO4 and H2O2m in Teflon vessels in a microwave unit. The samples were analyzed by ICP-OES instrument. The results were evaluated with statistical method. Results revealed a consistent picture showing distinct locations and years of the contamination history in the former mining area. Some elements are built into the trees more efficiently than other elements depending on mobility in the soil solution that is influenced by soil chemical properties, in turn. The majority of the metals become more mobile in acidic soil and heavy rain climatic conditions giving rise to availability of metal uptake by the studied trees.

Ground-water quality in the carbonate-rock aquifer of the Great Basin, Nevada and Utah, 2003

USGS Publications Warehouse

Schaefer, Donald H.; Thiros, Susan A.; Rosen, Michael R.

2005-01-01

The carbonate-rock aquifer of the Great Basin is named for the thick sequence of Paleozoic limestone and dolomite with lesser amounts of shale, sandstone, and quartzite. It lies primarily in the eastern half of the Great Basin and includes areas of eastern Nevada and western Utah as well as the Death Valley area of California and small parts of Arizona and Idaho. The carbonate-rock aquifer is contained within the Basin and Range Principal Aquifer, one of 16 principal aquifers selected for study by the U.S. Geological Survey’s National Water- Quality Assessment Program.Water samples from 30 ground-water sites (20 in Nevada and 10 in Utah) were collected in the summer of 2003 and analyzed for major anions and cations, nutrients, trace elements, dissolved organic carbon, volatile organic compounds (VOCs), pesticides, radon, and microbiology. Water samples from selected sites also were analyzed for the isotopes oxygen-18, deuterium, and tritium to determine recharge sources and the occurrence of water recharged since the early 1950s.Primary drinking-water standards were exceeded for several inorganic constituents in 30 water samples from the carbonate-rock aquifer. The maximum contaminant level was exceeded for concentrations of dissolved antimony (6 μg/L) in one sample, arsenic (10 μg/L) in eleven samples, and thallium (2 μg/L) in one sample. Secondary drinking-water regulations were exceeded for several inorganic constituents in water samples: chloride (250 mg/L) in five samples, fluoride (2 mg/L) in two samples, iron (0.3 mg/L) in four samples, manganese (0.05 mg/L) in one sample, sulfate (250 mg/L) in three samples, and total dissolved solids (500 mg/L) in seven samples.Six different pesticides or metabolites were detected at very low concentrations in the 30 water samples. The lack of VOC detections in water sampled from most of the sites is evidence thatVOCs are not common in the carbonate-rock aquifer. Arsenic values for water range from 0.7 to 45.7 μg/L, with a median value of 9.6 μg/L. Factors affecting arsenic concentration in the carbonate-rock aquifer in addition to geothermal heating are its natural occurrence in the aquifer material and time of travel along the flow path.Most of the chemical analyses, especially for VOCs and nutrients, indicate little, if any, effect of overlying land-use patterns on ground-water quality. The water quality in recharge areas for the aquifer where human activities are more intense may be affected by urban and/or agricultural land uses as evidenced by pesticide detections. The proximity of the carbonate-rock aquifer at these sites to the land surface and the potential for local recharge to occur through the fractured rock likely results in the occurrence of these and other land-surface related contaminants in the ground water. Water from sites sampled near outcrops of carbonate-rock aquifer likely has a much shorter residence time resulting in a potential for detection of anthropogenic or land-surface related compounds. Sites located in discharge areas of the flow systems or wells that are completed at a great depth below the land surface generally show no effects of land-use activities on water quality. Flow times within the carbonate-rock aquifer, away from recharge areas, are on the order of thousands of years, so any contaminants introduced at the land surface that will not degrade along the flow path have not reached the sampled sites in these areas.

PDS Archive Release of Apollo 11, Apollo 12, and Apollo 17 Lunar Rock Sample Images

NASA Technical Reports Server (NTRS)

Garcia, P. A.; Stefanov, W. L.; Lofgren, G. E.; Todd, N. S.; Gaddis, L. R.

2013-01-01

Scientists at the Johnson Space Center (JSC) Lunar Sample Laboratory, Information Resources Directorate, and Image Science & Analysis Laboratory have been working to digitize (scan) the original film negatives of Apollo Lunar Rock Sample photographs [1, 2]. The rock samples, and associated regolith and lunar core samples, were obtained during the Apollo 11, 12, 14, 15, 16 and 17 missions. The images allow scientists to view the individual rock samples in their original or subdivided state prior to requesting physical samples for their research. In cases where access to the actual physical samples is not practical, the images provide an alternate mechanism for study of the subject samples. As the negatives are being scanned, they have been formatted and documented for permanent archive in the NASA Planetary Data System (PDS). The Astromaterials Research and Exploration Science Directorate (which includes the Lunar Sample Laboratory and Image Science & Analysis Laboratory) at JSC is working collaboratively with the Imaging Node of the PDS on the archiving of these valuable data. The PDS Imaging Node is now pleased to announce the release of the image archives for Apollo missions 11, 12, and 17.

Bohemian circular structure, Czechoslovakia: Search for the impact evidence

NASA Technical Reports Server (NTRS)

Rajlich, Petr

1992-01-01

Test of the impact hypothesis for the origin of the circular, 260-km-diameter structure of the Bohemian Massif led to the discovery of glasses and breccias in the Upper Proterozoic sequence that can be compared to autogeneous breccias of larger craters. The black recrystallized glass contains small exsolution crystals of albite-oligoclase and biotite, regularly dispersed in the matrix recrystallized to quartz. The occurrence of these rocks is limited to a 1-sq-km area. It is directly underlain by the breccia of the pelitic and silty rocks cemented by the melted matrix, found on several tens of square kilometers. The melt has the same chemistry as rock fragments in major and in trace elements. It is slightly impoverished in water. The proportion of melted rocks to fragments varies from 1:5 to 10:1. The mineralogy of melt viens is the function of later, mostly contact metamorphism. On the contact of granitic plutons it abounds on sillimanite, cordierite, and small bullets of ilmenite. Immediately on the contact with syenodiorites it contains garnets. The metamorphism of the impact rock melt seems the most probable explanation of the mineralogy and the dry total fusion of rocks accompanied by the strong fragmentation. Other aspects of this investigation are discussed.

Bohemian circular structure, Czechoslovakia: Search for the impact evidence

NASA Astrophysics Data System (ADS)

Rajlich, Petr

Test of the impact hypothesis for the origin of the circular, 260-km-diameter structure of the Bohemian Massif led to the discovery of glasses and breccias in the Upper Proterozoic sequence that can be compared to autogeneous breccias of larger craters. The black recrystallized glass contains small exsolution crystals of albite-oligoclase and biotite, regularly dispersed in the matrix recrystallized to quartz. The occurrence of these rocks is limited to a 1-sq-km area. It is directly underlain by the breccia of the pelitic and silty rocks cemented by the melted matrix, found on several tens of square kilometers. The melt has the same chemistry as rock fragments in major and in trace elements. It is slightly impoverished in water. The proportion of melted rocks to fragments varies from 1:5 to 10:1. The mineralogy of melt viens is the function of later, mostly contact metamorphism. On the contact of granitic plutons it abounds on sillimanite, cordierite, and small bullets of ilmenite. Immediately on the contact with syenodiorites it contains garnets. The metamorphism of the impact rock melt seems the most probable explanation of the mineralogy and the dry total fusion of rocks accompanied by the strong fragmentation. Other aspects of this investigation are discussed.

Effect of pretreatment on rehydration, colour and nanoindentation properties of potato cylinders dried using a mixed-mode solar dryer.

PubMed

Dhalsamant, Kshanaprava; Tripathy, Punyadarshini P; Shrivastava, Shanker L

2017-08-01

Desirable quality estimation is an important consumer driver for wider acceptability of mixed-mode solar drying of potatoes in food industries. The aim of this study is to characterise rehydration, colour, texture, nanoindentaion and microstructure of dried potato samples and to establish the influence of pre-drying treatment on the above qualities. The water absorption capacity and rehydration ability of solar dried potato were significantly influenced by pretreatment followed by rehydration temperature and sample diameter. The redness index (a*) of pretreated dried samples was lower with simultaneous higher value of yellowness index (b*), chroma (C*) and hue angle (h*). Also, the average nanohardness (H) of pretreated samples increased significantly by 22.64% compared to that of untreated samples. The average reduced modulus (E r ) and Young's modulus (E s ) of dried potato samples were 1.865 GPa and 1.403 GPa, respectively. Moreover, creep displacement of 43.27 nm was traced in the untreated potato samples during a 20 s dwell time under a constant load of 200 µN in the nanoindentation test. Micrographs revealed more uniform pore spaces in pretreated samples. Pretreated, thinner potato samples achieved better quality dried products in terms of rehydration, colour, texture and nanohardness indices with significantly improved microstructure and creep resistance properties. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Dissolution and secondary mineral precipitation in basalts due to reactions with carbonic acid

NASA Astrophysics Data System (ADS)

Kanakiya, Shreya; Adam, Ludmila; Esteban, Lionel; Rowe, Michael C.; Shane, Phil

2017-06-01

One of the leading hydrothermal alteration processes in volcanic environments is when rock-forming minerals with high concentrations of iron, magnesium, and calcium react with CO2 and water to form carbonate minerals. This is used to the advantage of geologic sequestration of anthropogenic CO2. Here we experimentally investigate how mineral carbonation processes alter the rock microstructure due to CO2-water-rock interactions. In order to characterize these changes, CO2-water-rock alteration in Auckland Volcanic Field young basalts (less than 0.3 Ma) is studied before and after a 140 day reaction period. We investigate how whole core basalts with similar geochemistry but different porosity, permeability, pore geometry, and volcanic glass content alter due to CO2-water-rock reactions. Ankerite and aluminosilicate minerals precipitate as secondary phases in the pore space. However, rock dissolution mechanisms are found to dominate this secondary mineral precipitation resulting in an increase in porosity and decrease in rigidity of all samples. The basalt with the highest initial porosity and volcanic glass volume shows the most secondary mineral precipitation. At the same time, this sample exhibits the greatest increase in porosity and permeability, and a decrease in rock rigidity post reaction. For the measured samples, we observe a correlation between volcanic glass volume and rock porosity increase due to rock-fluid reactions. We believe this study can help understand the dynamic rock-fluid interactions when monitoring field scale CO2 sequestration projects in basalts.

ACOUSTICAL IMAGING AND MECHANICAL PROPERTIES OF SOFT ROCK AND MARINE SEDIMENTS

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

Thurman E. Scott, Jr., Ph.D.; Younane Abousleiman, Ph.D.; Musharraf Zaman, Ph.D., P.E.

2002-11-18

During the sixth quarter of this research project the research team developed a method and the experimental procedures for acquiring the data needed for ultrasonic tomography of rock core samples under triaxial stress conditions as outlined in Task 10. Traditional triaxial compression experiments, where compressional and shear wave velocities are measured, provide little or no information about the internal spatial distribution of mechanical damage within the sample. The velocities measured between platen-to-platen or sensor-to-sensor reflects an averaging of all the velocities occurring along that particular raypath across the boundaries of the rock. The research team is attempting to develop andmore » refine a laboratory equivalent of seismic tomography for use on rock samples deformed under triaxial stress conditions. Seismic tomography, utilized for example in crosswell tomography, allows an imaging of the velocities within a discrete zone within the rock. Ultrasonic or acoustic tomography is essentially the extension of that field technology applied to rock samples deforming in the laboratory at high pressures. This report outlines the technical steps and procedures for developing this technology for use on weak, soft chalk samples. Laboratory tests indicate that the chalk samples exhibit major changes in compressional and shear wave velocities during compaction. Since chalk is the rock type responsible for the severe subsidence and compaction in the North Sea it was selected for the first efforts at tomographic imaging of soft rocks. Field evidence from the North Sea suggests that compaction, which has resulted in over 30 feet of subsidence to date, is heterogeneously distributed within the reservoir. The research team will attempt to image this very process in chalk samples. The initial tomographic studies (Scott et al., 1994a,b; 1998) were accomplished on well cemented, competent rocks such as Berea sandstone. The extension of the technology to weaker samples is more difficult but potentially much more rewarding. The chalk, since it is a weak material, also attenuates wave propagation more than other rock types. Three different types of sensors were considered (and tested) for the tomographic imaging project: 600 KHz PZT, 1 MHz PZT, and PVDF film sensors. 600 KHz PZT crystals were selected because they generated a sufficiently high amplitude pulse to propagate across the damaged chalk. A number of different configurations were considered for placement of the acoustic arrays. It was decided after preliminary testing that the most optimum arrangement of the acoustic sensors was to place three arrays of sensors, with each array containing twenty sensors, around the sample. There would be two horizontal arrays to tomographically image two circular cross-sectional planes through the rock core sample. A third array would be vertically oriented to provide a vertical cross-sectional view of the sample. A total of 260 acoustic raypaths would be shot and acquired in the horizontal acoustic array to create each horizontal tomographic image. The sensors can be used as both acoustic sources or as acoustic each of the 10 pulsers to the 10 receivers.« less

Terrain analysis of the racetrack basin and the sliding rocks of Death Valley

USGS Publications Warehouse

Messina, P.; Stoffer, P.

2000-01-01

The Racetrack Playa's unusual surface features known as sliding rocks have been the subject of an ongoing debate and several mapping projects for half a century, although the causative mechanism remains unresolved. Clasts ranging in volume from large pebbles to medium boulders have, unwitnessed, maneuvered around the nearly flat dry lake over considerable distances. The controversy has persisted partly because eyewitness accounts of the phenomenon continue to be lacking, and the earlier mapping missions were limited in method and geographic range. In July 1996, we generated the first complete map of all observed sliding rock trails by submeter differential Global Positioning System (DGPS) mapping technology. The resulting map shows 162 sliding rocks and associated trails to an accuracy of approximately 30 cm. Although anemometer data are not available in the Racetrack wilderness, wind is clearly a catalyst for sliding rock activity; an inferred wind rose was constructed from DGPS trail segment data. When the entire trail network is examined in plan, some patterns emerge, although other (perhaps expected relations) remain elusive: terrain analysis of the surrounding topography demonstrates that the length and morphology of trails are more closely related to where rocks rested at the onset of motion than to any physical attribute of the rocks themselves. Follow-up surveys in May 1998, May 1999, August 1999, and November 1999 revealed little modification of the July, 1996 sliding rock configuration. Only four rocks were repositioned during the El Nino winter of 1997-1998, suggesting that activity may not be restricted to winter storms. (C) 2000 Elsevier Science B.V. All rights reserved.

Chlorine-36 tracing of salinity sources in the Dry Valleys of Victoria Land, Antarctica

NASA Astrophysics Data System (ADS)

Carlson, Catherine A.; Phillips, Fred M.; Elmore, David; Bentley, Harold W.

1990-02-01

Chlorine-36 was used to trace the origins of salts in six saline lakes in the Dry Valleys of Southern Victoria Land, Antarctica. Characteristic 36Cl signatures were estimated for the various potential chloride sources, which include atmospheric deposition, rock weathering, seawater, and deep ground water. 36Cl /Cl ratios were measured in natural waters and salts from the Dry Valleys. Dilute lake waters (Cl - < 100 mg/l) were found to have 36Cl /Cl ratios in the range 100 × 10 -15 to 1,700 × 10 -15, whereas saline waters (Cl - > 1000 mg/l) had ratios in the range 9 × 10 -15 to 40 × 10 -15. Simple mixing models were employed to quantify the relative contributions of the various chloride sources to Lake Vanda and Don Juan Pond. These results show that Lake Vanda has received its chloride from both deep ground water and the Onyx River. Don Juan Pond has received nearly all its chloride from deep ground water, probably ultimately from rock-water interaction. Deep ground water is the principal source of chloride to the lakes of Wright Valley. However, preliminary data suggest that marine-derived salts or relict sea water may be a significant source of chloride to the lakes of Taylor Valley, implying a possible recent marine invasion that did not affect Wright Valley.

Volatile Concentrations in Pyroclastic Obsidian: Two Case Studies

NASA Astrophysics Data System (ADS)

Wearn, K. M.; Cashman, K. V.; Wallace, P. J.

2002-12-01

Pyroclastic obsidian is abundant in fall deposits associated with Mt. Mazama's Cleetwood eruption and South Sister's Rock Mesa eruption. Measured concentrations of H2Ototal and CO2 in >300 obsidian samples from these two eruptions provide important information about both the style of degassing (open- vs. closed-system) and changes in eruptive conditions through the course of both eruptions. Obsidian clasts preserve a range of total H2O contents, with samples from lower stratigraphic levels displaying a wider range of water concentrations than those from the uppermost tephra layer sampled. All samples from the Cleetwood section contain <=1 wt% water, with those from the top of that deposit containing <0.4 wt%. Obsidian from the basal ash layer of the subsequent climactic eruption contains 0.1 - 0.8 wt% water. Obsidian fragments from the Rock Mesa eruption show a broader range in H2Ototal contents (from 0.1 to >3 wt%) than those from the Cleetwood eruption. At Rock Mesa, maximum total water contents generally decrease with increased stratigraphic height. However, this decrease is not strictly monotonic: fluctuations in maximum total water contents correspond to stratigraphic unit boundaries. In addition, the Rock Mesa event produced abundant obsidian with very low H2Ototal concentrations throughout the eruption. Dissolved molecular CO2 levels are below the detection limit in all of the Cleetwood and Mazama samples. This is not surprising, given the low initial CO2 measured in Cleetwood and Mazama melt inclusions by Bacon et al. (1992). CO2 concentrations in the Rock Mesa clasts range from <5 ppm to ~44 ppm, and are positively correlated with H2Ototal concentrations. Fluorine concentrations in Cleetwood and Mazama climactic obsidian clasts vary between ~510 and ~695 ppm, with climactic samples averaging slightly lower concentrations than Cleetwood samples. Fluorine concentrations in Rock Mesa obsidians are uniformly low (~300 to ~510 ppm). Chlorine contents of Cleetwood and Mazama climactic samples range from ~1400 ppm to ~1610 ppm. The Rock Mesa samples all contain less chlorine (~510 to ~1120 ppm) than the Cleetwood and climactic samples, and in the Rock Mesa obsidian, chlorine and total water are positively correlated. Stratigraphic variations in the volatile contents of pyroclastic obsidian support previous work suggesting that obsidian forms along the margins of the volcanic conduit and is eroded from the conduit walls by fragmenting magma. Both the Cleetwood and the Rock Mesa deposits indicate initial evacuation of shallow vanguard magma followed by a rapid increase in fragmentation depth. Both deposits also show a gradual decrease in the fragmentation depth through time, consistent with subsequent effusive activity in both cases. More puzzling is the apparent closed-system degassing trend defined by the H2O-CO2-Cl relations in the Rock Mesa obsidian samples, despite the loss of volatiles required for obsidian formation. This suggests that volatile data may also provide information on the relative time scales of volatile exsolution and loss and obsidian formation.

Pseudotachylyte increases the post-slip strength of faults

USGS Publications Warehouse

Proctor, Brooks; Lockner, David A.

2016-01-01

Solidified frictional melts, or pseudotachylytes, are observed in exhumed faults from across the seismogenic zone. These unique fault rocks, and many experimental studies, suggest that frictional melting can be an important process during earthquakes. However, it remains unknown how melting affects the post-slip strength of the fault and why many exhumed faults do not contain pseudotachylyte. Analyses of triaxial stick-slip events on Westerly Granite (Rhode Island, USA) sawcuts at confining pressures from 50 to 400 MPa show evidence for frictional heating, including some events energetic enough to generate surface melt. Total and partial stress drops were observed with slip as high as 6.5 mm. We find that in dry samples following melt-producing stick slip, the shear failure strength increased as much as 50 MPa, while wet samples had <10 MPa strengthening. Microstructural analysis indicates that the strengthening is caused by welding of the slip surface during melt quenching, suggesting that natural pseudotachylytes may also strengthen faults after earthquakes. These results predict that natural pseudotachylyte will inhibit slip reactivation and possibly generate stress heterogeneities along faults. Wet samples do not exhibit melt welding, possibly because of thermal pressurization of water reducing frictional heating during slip.

The Effect of Petrographic Characteristics on Engineering Properties of Conglomerates from Famenin Region, Northeast of Hamedan, Iran

NASA Astrophysics Data System (ADS)

Khanlari, G. R.; Heidari, M.; Noori, M.; Momeni, A.

2016-07-01

To assess relationship between engineering characteristics and petrographic features, conglomerates samples related to Qom formation from Famenin region in northeast of Hamedan province were studied. Samples were tested in laboratory to determine the uniaxial compressive strength, point load strength index, modulus of elasticity, porosity, dry and saturation densities. For determining petrographic features, textural and mineralogical parameters, thin sections of the samples were prepared and studied. The results show that the effect of textural characteristics on the engineering properties of conglomerates supposed to be more important than mineralogical composition. It also was concluded that the packing proximity, packing density, grain shape and mean grain size, cement and matrix frequency are as textural features that have a significant effect on the physical and mechanical properties of the studied conglomerates. In this study, predictive statistical relationships were developed to estimate the physical and mechanical properties of the rocks based on the results of petrographic features. Furthermore, multivariate linear regression was used in four different steps comprising various combinations of petrographical characteristics for each engineering parameters. Finally, the best equations with specific arrangement were suggested to estimate engineering properties of the Qom formation conglomerates.

Energy dispersive X-ray fluorescence (EDXRF) equipment calibration for multielement analysis of soil and rock samples

NASA Astrophysics Data System (ADS)

de Moraes, Alex Silva; Tech, Lohane; Melquíades, Fábio Luiz; Bastos, Rodrigo Oliveira

2014-11-01

Considering the importance to understand the behavior of the elements on different natural and/or anthropic processes, this study had as objective to verify the accuracy of a multielement analysis method for rocks characterization by using soil standards as calibration reference. An EDXRF equipment was used. The analyses were made on samples doped with known concentration of Mn, Zn, Rb, Sr and Zr, for the obtainment of the calibration curves, and on a certified rock sample to check the accuracy of the analytical curves. Then, a set of rock samples from Rio Bonito, located in Figueira city, Paraná State, Brazil, were analyzed. The concentration values obtained, in ppm, for Mn, Rb, Sr and Zr varied, respectively, from 175 to 1084, 7.4 to 268, 28 to 2247 and 15 to 761.

Permeability measurements on rock samples from Unzen Scientific Drilling Project Drill Hole 4 (USDP-4)

NASA Astrophysics Data System (ADS)

Watanabe, Tohru; Shimizu, Yuhta; Noguchi, Satoshi; Nakada, Setsuya

2008-07-01

Permeability measurement was made on five rock samples from USDP-4 cores. Rock samples were collected from the conduit zone and its country rock. One sample (C14-1-1) is considered as a part of the feeder dyke for the 1991-1995 eruption. The transient pulse method was employed under confining pressure up to 50 MPa. Compressional wave velocity was measured along with permeability. The measured permeability ranges from 10 - 19 to 10 - 17 m 2 at the atmospheric pressure, and is as low as that reported for tight rocks such as granite. The permeability decreases with increasing confining pressure, while the compressional wave velocity increases. Assuming that pores are parallel elliptical tubes, the pressure dependence of permeability requires aspect ratio of 10 - 4 -10 - 2 at the atmospheric pressure. The pore aperture is estimated to be less than 1 μm. The estimated aspect ratio and pore aperture suggest that connectivity of pores is maintained by narrow cracks. The existence of cracks is supported by the pressure dependence of compressional wave velocity. Narrow cracks (< 1 μm) are observed in dyke samples, and they must have been created after solidification. Dyke samples do not provide us information of pore structures during degassing, since exsolved gas has mostly escaped and pores governing the gas permeable flow should have been lost. Both dyke and country rock samples provide us information of materials around ascending magma. Although the measured small-scale permeability cannot be directly applied to geological-scale processes, it gives constrains on studies of large-scale permeability.

Finite strain analysis of metavolcanics and metapyroclastics in gold-bearing shear zone of the Dungash area, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Kassem, Osama M. K.; Abd El Rahim, Said H.

2014-11-01

The Dungash gold mine area is situated in an EW-trending quartz vein along a shear zone in metavolcanic and metasedimentary host rocks in the Eastern Desert of Egypt. These rocks are associated with the major geologic structures, which are attributed to various deformational stages of the Neoproterozoic basement rocks. Field geology, finite strain and microstructural analyses were carried out and the relation-ships between the lithological contacts and major/minor structures have been studied. The R f/ϕ and Fry methods were applied on the metavolcano-sedimentary and metapyroclastic samples from 5 quartz veins samples, 7 metavolcanics samples, 3 metasedimentary samples and 4 metapyroclastic samples in Dungash area. Finite-strain data show that a low to moderate range of deformation of the metavolcano-sedimentary samples and axial ratios in the XZ section range from 1.70 to 4.80 for the R f/ϕ method and from 1.65 to 4.50 for the Fry method. We conclude that finite strain in the deformed rocks is of the same order of magnitude for all units of metavolcano-sedimentary rocks. Furthermore, the contact between principal rock units is sheared in the Dungash area under brittle to semi-ductile deformation conditions. In this case, the accumulated finite strain is associated with the deformation during thrusting to assemble nappe structure. It indicates that the sheared contacts have been formed during the accumulation of finite strain.

Terrestrial microbes in martian and chondritic meteorites

NASA Astrophysics Data System (ADS)

Airieau, S.; Picenco, Y.; Andersen, G.

2007-08-01

Introduction: The best extraterrestrial analogs for microbiology are meteorites. The chemistry and mineralogy of Asteroid Belt and martian (SNC) meteorites are used as tracers of processes that took place in the early solar system. Meteoritic falls, in particular those of carbonaceous chondrites, are regarded as pristine samples of planetesimal evolution as these rocks are primitive and mostly unprocessed since the formation of the solar system 4.56 billion years ago. Yet, questions about terrestrial contamination and its effects on the meteoritic isotopic, chemical and mineral characteristics often arise. Meteorites are hosts to biological activity as soon as they are in contact with the terrestrial biosphere, like all rocks. A wide biodiversity was found in 21 chondrites and 8 martian stones, and was investigated with cell culture, microscopy techniques, PCR, and LAL photoluminetry. Some preliminary results are presented here. The sample suite included carbonaceous chondrites of types CR, CV, CK, CO, CI, and CM, from ANSMET and Falls. Past studies documented the alteration of meteorites by weathering and biological activity [1]-[4]. Unpublished observations during aqueous extraction for oxygen isotopic analysis [5], noted the formation of biofilms in water in a matter of days. In order to address the potential modification of meteoritic isotopic and chemical signatures, the culture of microbial contaminating species was initiated in 2005, and after a prolonged incubation, some of the species obtained from cell culture were analyzed in 2006. The results are preliminary, and a systematic catalog of microbial contaminants is developing very slowly due to lack of funding. Methods: The primary method was cell culture and PCR. Chondrites. Chondritic meteorite fragments were obtained by breaking stones of approximately one gram in sterile mortars. The core of the rocks, presumably less contaminated than the surface, was used for the present microbial study, and the remaining fragments of the samples were used for amino acid and isotopic analyses [6]. Some samples were fragments of dried and wet meteorites isolated in centrifuge tubes after a 10-day water extraction. Sabouraud Dextrose (dilutions 1:10 and 1:1000), Bacto Agar, LB Broth Miller (dilutions 1:10 and 1:1000), and R2A agar (1:1 and 1:1000), were autoclaved and cooled in culture plates inside a clean hood for cell culture. Some controls retained sterile moist agar still adhering to the perimeter of the plates for up to 18 months, and validated the sterile technique. Cell culture, PCR and microscopy documented a diversity of archea, prokaryotes and eukaryotes in these samples [7]. The plates displaying microbial growth at room temperature after 6 weeks or less were used to produce streak plates and isolate colonies of individual species for long term freezing in Eppendorf tubes. Any plate with biological growth along the perimeter of the plate was discarded. The plates without microbial activity after 6 weeks were stored in a fridge for 18 months. Control plates, exposed to the clean hood, laboratory room, used gloves, and weighing paper used in the analyses, sustained the prolonged storage with no sign of microbial activity that could be related to the analysis method. Dust grains and water extracts from the meteorites were spread on agar surfaces in cell culture Petri dishes in a clean hood. SNC samples.In early 2005, the surface of SNC stones in the USNM curation facility were brushed with sterile swabs. Fallen dust grains were collected on weighing paper and isolated in sterile tubes. The sample suite included Zagami USNM 6545, Lafayette USNM 1505, Los Angeles USNM 7052, Shergotty USNM 321, Nakhla USNM 5892, Nakhla USNM 426 (117.4 g) and Nakhla USNM 426 (18.2 g), and Chassigny USNMMNHN 2524. The controls, worker's gloves, blank swabs, and weighing paper exhibited no microbial activity in subsequent months. The cell culture was conducted with Sabouraud Dextrose and R2A only, by deposition of dry grains onto the surface of agar in culture plates that were incubated at 20 Celsius 2 weeks, then at 35 Celsius 3 days, and finally at 4 Celsius for 18 months. Limulus Amoebocyte Lysate (LAL Assay) measurements of the swabs [7] revealed low biological activity in all SNCs, except in a small piece of Nakhla USNM 426 (18.2 g) (activity below detection limit) and Chassigny (data unavailable). The LAL technique assesses gram negative bacterial equivalents. Culture sample material was recovered from the agar plates using sterile pipette tips. The material was added to 100 uL sterile water. This material was boiled for 15 min. in a water bath to lyse the cells and inactivate enzymes. 10 uL of the boiled lysate was used as template in PCR. Universal bacterial primers (27F and 1492R) were used to amplify a major portion of the 16S rRNA gene. PCR product was purified using a Qiagen MinElute PCR Purification kit and then sent for sequencing. Results and Comments: GRA 95229. Biological growth out of dust grains deposited on the agar surface was visible with the naked eye, and occurred after incubation in a fridge for 10 months. Leoville. Biological growth occurred at the contact of a dust grain and the agar surface after 1 month. It continued to expand outside a dust grain deposited on Sabouraud Dextrose 1:1000, while stored at 20 Celsius for 12 months. The fan shaped outgrowth reached about 1 cm on either side of the meteorite grain and dried. DNA was recovered, and PCR products yielded sequences of a Bacillus spp. Bacillus is a common soil bacterial genus, and the close sequence relatives of this isolate were no exception. They were rock or soil Bacillus, and have been found in Allende [4]. EET 87770. Rock fragments were wet for 8 months (Millipore water) in a sterile centrifuge tube, and were used to make a spread plate that dried over a period of 10 months. The yellow dried colonies yielded good PCR product and the sequences were compared to other GenBank sequences using the BLAST program. The closest matches were in the genus Microbacterium. Soil and plant isolates were close relatives by sequence comparison. Los Angeles. After 11 months of incubation in a fridge, a yellow colony grew at the center of a culture plate of Los Angeles dust grains (1:1000 R2A). There was no cell activity in the other agars. A DNA extraction yielded no usable results [7]. Sequencing was not performed because the culture plate became contaminated with outside organisms that overtook the colony of interest. Conclusions: The sequences for EET 87770 and Leoville were of a good quality and the sequence reads were long, so the data are clear that these are typical soil and/or plant-related bacteria commonly found in Earth habitats. Microbial species present in a dozen chondritic samples from isolates are not yet identified, and the contaminant in Los Angeles needs to be recovered. In addition, isotopic analyses of samples with various amounts of microbial contamination could help quantified isotopic impact of microbes on protoplanetary chemistry in these rocks. References : [1] Gounelle, M. and Zolensky M. LPS, (2001) LPS XXXII, Abstract #999. [2] Fries, M. et al. (2005) Meteoritical Society Meeting 68, Abstract # 5201. [3] Burckle, L. H. and Delaney, J. S (1999) Meteoritics & Planet. Sci., 32, 475-478. [4] Whitby, C. et al. (2000) ) LPS XXXI, Abstract #1732. [5] Airieau, S. A. et al (2005) Geochim. Cosmochim. Acta, 69, 4166-4171. [6] Unpublished data, with H. J. Cleaves, A. Aubrey, J. Bada (Scripps Institution of Oceanography), M. Thiemens (UC San Diego) and M. Fogel (Carnegie Institution of Washington). [7] Unpublished data, with A. Steele (CIW), and N. Wainwright (Marine Biological Laboratory). Acknowledgements: Lisa Welleberger for access to SNC samples at USNM; Ralph Harvey for organizing ANSMET; Denise C. Thiry and Andrew Steele for long term storage of samples, NormWainwright for LAL measurements. A small portion of this work was funded with a NASA Cosmochemistry grant, ( P. I. Thiemens).

Overall voice and strain level analysis in rock singers.

PubMed

Gonsalves, Aline; Amin, Elisabeth; Behlau, Mara

2010-01-01

overall voice and strain level analysis in rock singers. to analyze the voice o rock singers according to two specific parameters: overall level of vocal deviation (OLVD) and strain level (SL); to compare these parameters in three different music samples. participants were 26 male rock singers, ranging in age from 17 to 46 years (mean = 29.8 years). All of the participants answered a questionnaire for sample characterization and were submitted to the recording of three voice samples: Brazilian National Anthem (BNA), Satisfaction and self-selected repertoire song (RS). Voice samples were analyzed by five speech-language pathologists according to OLVD and SL. Statistical analysis was done using the software SPSS, version 13.0. statistically significant differences were observed for the mean values of OLVD and SL during the performance of Satisfaction (OLVD = 32.8 and SL = 0.024 / p=0.024) and during the RS performance (OLVD = 38.4 and SL = 55.8 / p=0.010). The values of OLVD and SL are directly proportional to the samples of the BNA* and RS**, i.e. the higher the strain the higher the OLVD (p,0.001*; p=0.010**). When individually analyzing the three song samples, it is observed that the OLVD does not vary significantly among them. However, the mean values present a trend to increase from non-rock to rock performances (24.0 BNA / 32.8 Satisfaction / 38.4 RS). The level of strain found during the BNA performance presents statistically significant difference when compared to the rock performances (Satisfaction and RS, p=0.008 and p=0.001). the obtained data suggest that rock style is related to the greater use of vocal strain and that this strain does not necessarily impose a negative impression to the voice, but corresponds to a common interpretative factor related to this style of music.

Geochemical and geochronological constrains on the Chiang Khong volcanic rocks (northwestern Thailand) and its tectonic implications

NASA Astrophysics Data System (ADS)

Qian, Xin; Feng, Qinglai; Chonglakmani, Chongpan; Monjai, Denchok

2013-12-01

Volcanic rocks in northwestern Thailand exposed dominantly in the Chiang Khong area, are commonly considered to be genetically linked to the tectonic evolution of the Paleo-Tethyan Ocean. The volcanic rocks consist mainly of andesitic to rhyolitic rocks and are traditionally mapped as Permian-Triassic sequences. Our zircon U-Pb geochronological results show that two andesitic samples (TL-1-B and TL-31-B), are representative of the Doi Yao volcanic zone, and give a mean weighted age of 241.2±4.6 Ma and 241.7±2.9 Ma, respectively. The rhyolitic sample (TL-32-B1) from the Doi Khun Ta Khuan volcanic zone erupted at 238.3±3.8 Ma. Such ages indicate that Chiang Khong volcanic rocks erputed during the early Middle Triassic period. Seven samples from the Doi Yao and Doi Khun Ta Khuan zones exhibit an affinity to arc volcanics. Three rhyolitic samples from the Chiang Khong area have a geochemical affinity to both arc and syn-collisional volcanic rocks. The Chiang Khong arc volcanic rocks can be geochemically compared with those in the Lampang area in northern Thailand, also consistent with those in Jinghong area of southwestern Yunnan. This indicates that the Chiang Rai arc-volcanic zone might northwardly link to the Lancangjiang volcanic zone in southwestern China.

Petrophysical laboratory invertigations of carbon dioxide storage in a subsurface saline aquifer in Ketzin/Germany within the scope of CO2SINK

NASA Astrophysics Data System (ADS)

Zemke, K.; Kummmerow, J.; Wandrey, M.; Co2SINK Group

2009-04-01

Since June of 2008 carbon dioxide has been injected into a saline aquifer at the Ketzin test site [Würdemann et al., this volume]. The food grade CO2 is injected into a sandstone zone of the Stuttgart formation at ca. 650 m depth at 35°C reservoir temperature and 62 bar reservoir pressure. With the injection of CO2 into the geological formation, chemical and physical reservoir characteristics are changed depending on pressure, temperature, fluid chemistry and rock composition. Fluid-rock interaction could comprise dissolution of non-resistant minerals in CO2-bearing pore fluids, cementing of the pore space by precipitating substances from the pore fluid, drying and disintegration of clay minerals and thus influence of the composition and activities of the deep biosphere. To testing the injection behaviour of CO2 in water saturated rock and to evaluate the geophysical signature depending on the thermodynamic conditions, flow experiments with water and CO2 have been performed on cores of the Stuttgart formation from different locations including new wells of ketzin test site. The studied core material is an unconsolidated fine-grained sandstone with porosity values from 15 to 32 %. Permeability, electrical resistivity, and sonic wave velocities and their changes with pressure, saturation and time have been studied under simulated in situ conditions. The flow experiments conducted over several weeks with brine and CO2 showed no significant changes of resistivity and velocity and a slightly decreasing permeability. Pore fluid analysis showed mobilization of clay and some other components. A main objective of the CO2Sink laboratory program is the assessment of the effect of long-term CO2 exposure on reservoir rocks to predict the long-term behaviour of geological CO2 storage. For this CO2 exposure experiments reservoir rock samples were exposed to CO2 saturated reservoir fluid in corrosion-resistant high pressure vessels under in situ temperature and pressure conditions over a period of several months. Before and after the CO2 exposure experiment cyclic measurements of physical properties were carried out on these cores in a mechanical testing system. After experimental runs of up to 3 months no significant changes in flow and petrophysical data were observed. [For the microbilogical studies see Wandrey et al., this volume.] To study the impact of fluid-rock interactions on petrophysical parameters, porosity and pore radii distribution have been investigated before and after the experiment by NMR relaxation and mercury-injection. NMR measurements on rock core plugs saturated with brine may return valuable information on the porous structure of the rock core. The distribution of NMR-T2 values (CPMG) reflects the pore sizes within the rock core. NMR pore size is a derivative of the ratio pore surface/volume. The mercury injection pore size is an area-equivalent diameter of the throats connecting the pore system. Most of the tested samples show in the NMR measurements a slightly increasing porosity and a higher part of large pores. The mercury measurements and thin- section for microstructural characterisation after the CO2 exposure will be done at a later date.

Comparative sound velocity measurements between porous rock and fully-dense material under crustal condition: The cases of Darley Dale sandstone and copper block

NASA Astrophysics Data System (ADS)

Kung, J.; Chien, Y. V.; Wu, W.; Dong, J.; Chang, Y.; Tsai, C.; Yang, M.; Wang, K.

2012-12-01

Previous studies showed that the voids and their geometry in the sedimentary rocks have great influence on the compressibility of rock, which reflects on its elastic velocities. Some models were developed to discuss the relations among velocity, porosity and void geometry. Therefore, the information of porosity, and void geometry and its distribution in rock is essential for understanding how the elastic properties of porous rocks affected by their poregeometry. In this study, we revisited a well-studied porous rock, Darley Dale sandstone, which has been studied by different groups with different purposes. Most of them are the deformation experiments. Different from previous studies, we measured the sound velocity of Darley dale sandstone under hydrostatic conditions. Also, we employed different techniques to investigate the pore geometry and porosity of Darley Dale sandstone to gain the insight of velocity changing behavior under the crustal conditions. Here, we measured a fully-dense copper block for a comparison. We performed X-ray CT scanning (XCT) to image the pore space of sandstone to construct the 3-D image of pore geometry, distribution and the pore size. The CT image data are allowed us to estimate the porosity of sandstone, too. One the other hand, the porosity of sample was measured using imbibitions method at ambient conditions and helium porosimeter at high pressure (up to 150 MPa). A set of specimens were cored from Darley Dale sandstone block. P and S wave velocities of specimens were measured at ambient conditions. We also performed high pressure velocity measurements on a selected rock specimen and a copper block up to 150 MPa under dry condition. Porosity of a set of rock specimens measured by imbibitions method was spanned from 6% to 15%, largely distributed within a range of 8%-11%. Compared the porosity obtained from three different techniques, imbibitions method, helium porosimeter and XCT, values from those measurements are in good agreement within 2%. With a wide porosity range, the measured P and S wave velocities of this set specimens presented a linear function of porosity, the velocity varying from 2.40 km/s to 4.00 km/s for P wave and 1.70 km/s to 2.40 km/s for S wave, yielding a tight value of 1.6(1) for Vp/Vs ratio. High pressure velocity and porosity measurements in the selected specimen showed both P and S wave velocities markedly increasing at low pressure regime (< 40 MPa) and reaching plateau above 60 MPa while the pore closure reaching a steady minimum beyond pressure of 60 MPa. From the measurement of copper block at high pressure, we learned that the velocity at lower pressure regime is disturbed by the coupling of the interface between wave guide and sample, and the pressure range within this kind of experiments has no or little effect on the velocity (or the elasticity) of fully-dense material. Combining the results of porosity and velocity from above measurements, we conclude that the change of velocity observed in the porous rocks under crustal condition should be mainly affected by the closure of narrow microcracks at high pressure.

Magnetic Grain-size Proxies in Loessic Soils and Their Potential use in Paleorainfall Reconstruction

NASA Astrophysics Data System (ADS)

Machac, T. A.; Geiss, C. E.; Zanner, C. W.

2005-05-01

As part of our ongoing rock-magnetic study of loessic soil profiles we sampled over 70 in Nebraska, Iowa, Missouri and Illinois. Our sampling sites are located in stable upland positions and extend along a rainfall gradient which ranges from an average annual precipitation of less than 500 mm/year in southwestern Nebraska to almost 1000 mm/year in central Missouri. Soil cores were obtained with the aid of a hydraulic soil probe, described and subsampled into small plastic bags. Samples were air-dried in the laboratory and the < 2mm fraction was used for magnetic analyses. We measured magnetic susceptibility X and several remanence parameters (ARM, IRM) for all samples. Hysteresis measurements, IRM acquisition curves and time dependence of IRM acquisition were measured for a subset of samples. All samples show magnetically enhanced A- and B-horizons, which results in increased values of X, ARM and IRM. Changes in the ratio of ARM/IRM suggest an increase in the relative abundance of stable single domain (SSD) particles. VRM analyses show that the upper soil horizons are enhanced in ultrafine superparamagnetic (SP) ferrimagnets as well. Changes in the relative abundance of SP and SSD ferrimagnets along our transsect correlates well with the modern precipitation gradient, suggesting the use of grain-size dependent magnetic parameter as a potential paleorainfall proxy when analyzing paleosols.

The Importance of Measuring Mercury in Wood

NASA Astrophysics Data System (ADS)

Yang, Y.; Yanai, R. D.; Driscoll, C. T.; Montesdeoca, M.

2014-12-01

Forests are important receptors of Hg deposition, and biological Hg hotspots occur mainly in forested regions, but few efforts have been made to determine the Hg content of trees. Mercury concentrations in stem tissue are lower than the foliage and bark, so low that they have often been below detection limits, especially in hardwood species. However, because wood is the largest component of forest biomass, it can be a larger Hg pool than the foliage, and thus quantifying concentrations in wood is important to Hg budgets in forests. The objective of our study was to determine the methods necessary to detect Hg in bole wood of four tree species, including two hardwoods and two conifers. We also evaluated the effect of air-drying and oven-drying samples on Hg recovery, compared to freeze-drying samples prior to analysis, which is the standard procedure. Many archived wood samples that were air-dried or oven-dried could be appropriate for Hg analysis if these methods could be validated; few are freeze-dried. We analyzed samples for total Hg using thermal decomposition, catalytic conversion, amalgamation, and atomic absorption spectrophotometry (Method 7473, USEPA 1998). The result of the method detection limit study was 1.27 ng g-1, based on apple leaf standards (NIST 1515, 44 ± 4 ng/g). Concentrations in the hardwood species were 1.48 ± 0.23 ng g-1 for sugar maple and 1.75 ± 0.14 ng g-1 for American beech. Concentrations were higher in red spruce and balsam fir. Samples that were analyzed fresh, freeze-dried, or oven-dried at 65 ˚C were in close agreement, after correcting for moisture content. However, Hg concentrations were 34 to 45% too high in the air-dry samples, presumably reflecting absorption from the atmosphere, and they were 44 to 66% too low in the samples oven-dried at 103 ˚C, presumably due to volatilization. We recommend that samples be freeze-dried or oven-dried at 65 ˚C for analysis of Hg in wood; archived samples that have been oven-dried at higher temperatures or stored exposed to the air may not be suitable for Hg analysis.

Determination and distribution of rare earth elements in beach rock samples using instrumental neutron activation analysis (INAA)

NASA Astrophysics Data System (ADS)

Ravisankar, R.; Manikandan, E.; Dheenathayalu, M.; Rao, Brahmaji; Seshadreesan, N. P.; Nair, K. G. M.

2006-10-01

Beach rocks are a peculiar type of formation when compared to other types of rocks. Rare earth element (REE) concentrations in beach rock samples collected from the South East Coast of Tamilnadu, India, have been measured using the instrumental neutron activation analysis (INAA) single comparator K0 method. The irradiations were carried out using a thermal neutron flux of ˜10 11 n cm -2 s -1 at 20 kW power using the Kalpakkam mini reactor (KAMINI), IGCAR, Kalpakkam, Tamilnadu. Accuracy and precision were evaluated by assaying irradiated standard reference material (SRM 1646a estuarine sediment). The results being found to be in good agreement with certified values. REE elements have been determined from 15 samples using high-resolution gamma spectrometry. The geochemical behavior of REE in beach rock, in particular REE (chondrite-normalized) pattern has been studied.

Rollerjaw Rock Crusher

NASA Technical Reports Server (NTRS)

Peters, Gregory; Brown, Kyle; Fuerstenau, Stephen

2009-01-01

The rollerjaw rock crusher melds the concepts of jaw crushing and roll crushing long employed in the mining and rock-crushing industries. Rollerjaw rock crushers have been proposed for inclusion in geological exploration missions on Mars, where they would be used to pulverize rock samples into powders in the tens of micrometer particle size range required for analysis by scientific instruments.

ROCK Inhibition Promotes Attachment, Proliferation, and Wound Closure in Human Embryonic Stem Cell–Derived Retinal Pigmented Epithelium

PubMed Central

Croze, Roxanne H.; Thi, William J.; Clegg, Dennis O.

2016-01-01

Purpose Nonexudative (dry) age-related macular degeneration (AMD), a leading cause of blindness in the elderly, is associated with the loss of retinal pigmented epithelium (RPE) cells and the development of geographic atrophy, which are areas devoid of RPE cells and photoreceptors. One possible treatment option would be to stimulate RPE attachment and proliferation to replace dying/dysfunctional RPE and bring about wound repair. Clinical trials are underway testing injections of RPE cells derived from pluripotent stem cells to determine their safety and efficacy in treating AMD. However, the factors regulating RPE responses to AMD-associated lesions are not well understood. Here, we use cell culture to investigate the role of RhoA coiled coil kinases (ROCKs) in human embryonic stem cell–derived RPE (hESC-RPE) attachment, proliferation, and wound closure. Methods H9 hESC were spontaneously differentiated into RPE cells. hESC-RPE cells were treated with a pan ROCK1/2 or a ROCK2 only inhibitor; attachment, and proliferation and cell size within an in vitro scratch assay were examined. Results Pharmacological inhibition of ROCKs promoted hESC-RPE attachment and proliferation, and increased the rate of closure of in vitro wounds. ROCK inhibition decreased phosphorylation of cofilin and myosin light chain, suggesting that regulation of the cytoskeleton underlies the mechanism of action of ROCK inhibition. Conclusions ROCK inhibition promotes attachment, proliferation, and wound closure in H9 hESC-RPE cells. ROCK isoforms may have different roles in wound healing. Translational Relevance Modulation of the ROCK-cytoskeletal axis has potential in stimulating wound repair in transplanted RPE cells and attachment in cellular therapies. PMID:27917311

Evaluating Core Quality for a Mars Sample Return Mission

NASA Technical Reports Server (NTRS)

Weiss, D. K.; Budney, C.; Shiraishi, L.; Klein, K.

2012-01-01

Sample return missions, including the proposed Mars Sample Return (MSR) mission, propose to collect core samples from scientifically valuable sites on Mars. These core samples would undergo extreme forces during the drilling process, and during the reentry process if the EEV (Earth Entry Vehicle) performed a hard landing on Earth. Because of the foreseen damage to the stratigraphy of the cores, it is important to evaluate each core for rock quality. However, because no core sample return mission has yet been conducted to another planetary body, it remains unclear as to how to assess the cores for rock quality. In this report, we describe the development of a metric designed to quantitatively assess the mechanical quality of any rock cores returned from Mars (or other planetary bodies). We report on the process by which we tested the metric on core samples of Mars analogue materials, and the effectiveness of the core assessment metric (CAM) in assessing rock core quality before and after the cores were subjected to shocking (g forces representative of an EEV landing).

Microstructural evidence of melting in crustal rocks (Invited)

NASA Astrophysics Data System (ADS)

Holness, M. B.; Cesare, B.; Sawyer, E. W.

2010-12-01

The signature of the former presence of melt on a microscopic scale is highly variable, subject to modification both during the melting event and during its subsequent history. Static pyrometamorphism results in melt films on grain boundaries between reactant phases. If a volume increase is involved, melting results in hydrofracture. On a longer timescale, as demonstrated by fragments of the crustal source in lava flows at El Hoyazo (SE Spain), melt occurs throughout the rock. These examples are highly unusual: the great majority of rocks that underwent melting cooled more slowly, permitting microstructural modification driven by a combination of textural equilibration, reaction and deformation. In the absence of deformation, and at constant temperature, melt-bearing rocks approach textural equilibrium, characterised by uniform grain size, smoothly curved grain boundaries and the establishment at all three-grain junctions of the equilibrium dihedral angle. The dihedral angle controls melt connectivity, with consequences for melt mobility and rock rheology. However, deformation is the rule rather than the exception in regional metamorphic terrains with profound effects on melt distribution. If deformation occurs predominantly by diffusive processes, textural equilibration can keep pace. At higher deformation rates melt is squeezed into planar pockets aligned parallel to the shearing direction or perpendicular to the extensional stress. Microstructures formed during solidification are controlled by cooling rate, H2O, and the size of the melt pockets. Large pockets solidify to look like igneous rocks. In small pores the supersaturation required for crystal growth is high and melt persist to lower temperatures, even being preserved as tiny glassy inclusions (“nanogranites”) in regional terranes. The pore size effect changes crystallization order, resulting in small, highly cuspate grains on grain boundaries with low dihedral angles. Crystallisation microstructures of poly-component liquids are highly dependent on diffusion rates, and therefore H2O content. Dry conditions result in diffusion-limited crystallisation to form intergrowths and symplectites (e.g. granophyre). The cooling rate must be slow in order to nucleate and grow individual grains from the melt. If the melt was primarily concentrated in thick films on grain boundaries this results in the “string of beads” texture. If there is sufficient water, and the rocks stay sufficiently hot, the microstructures will move towards a granular texture, driven by the reduction in interfacial energy. Highly cuspate pseudomorphs of melt at three-grain junctions will become rounded as the dihedral angle increases (generally towards the range 110-140°). Melt-related microstructures are more likely to be retained in dry rocks: in migmatite terranes in which melting was driven by infiltration of aqueous fluids and where melt extraction wasn’t pervasive, microstructures are likely to have been significantly modified by sub-solidus recrystallisation, especially likely if the rock underwent intense deformation on the retrograde path.

NASA Lunar Sample Education Disk Program - Space Rocks for Classrooms, Museums, Science Centers and Libraries

NASA Astrophysics Data System (ADS)

Allen, J. S.

2009-12-01

NASA is eager for students and the public to experience lunar Apollo rocks and regolith soils first hand. Lunar samples embedded in plastic are available for educators to use in their classrooms, museums, science centers, and public libraries for education activities and display. The sample education disks are valuable tools for engaging students in the exploration of the Solar System. Scientific research conducted on the Apollo rocks has revealed the early history of our Earth-Moon system. The rocks help educators make the connections to this ancient history of our planet as well as connections to the basic lunar surface processes - impact and volcanism. With these samples educators in museums, science centers, libraries, and classrooms can help students and the public understand the key questions pursued by missions to Moon. The Office of the Curator at Johnson Space Center is in the process of reorganizing and renewing the Lunar and Meteorite Sample Education Disk Program to increase reach, security and accountability. The new program expands the reach of these exciting extraterrestrial rocks through increased access to training and educator borrowing. One of the expanded opportunities is that trained certified educators from science centers, museums, and libraries may now borrow the extraterrestrial rock samples. Previously the loan program was only open to classroom educators so the expansion will increase the public access to the samples and allow educators to make the critical connections of the rocks to the exciting exploration missions taking place in our solar system. Each Lunar Disk contains three lunar rocks and three regolith soils embedded in Lucite. The anorthosite sample is a part of the magma ocean formed on the surface of Moon in the early melting period, the basalt is part of the extensive lunar mare lava flows, and the breccias sample is an important example of the violent impact history of the Moon. The disks also include two regolith soils and orange glass from a pyroclastic deposit. The loan program also includes Meteorite Disks containing six meteorites that will help educators share the early history of the solar system with students and the public. Educators may borrow either lunar or meteorite disks through Johnson Space Center Curatorial Office. In trainings provided by the NASA Aerospace Education Services Program specialists, educators certified to borrow the disk learn about education resources, the proper use of the samples, and the special security for care and shipping of the disks. The Lunar and Meteorite Sample Education Disk Program is set up to bridge to new education programs that will carry NASA exploration to more people. Getting Space Rocks out to the public and connecting the public to the current space exploration missions is the focus the NASA disk loan program.

Amino acids and hydrocarbons approximately 3,800-Myr old in the Isua rocks, southwestern Greenland

NASA Technical Reports Server (NTRS)

Nagy, B.; Engel, M. H.; Zumberge, J. E.; Ogino, H.; Chang, S. Y.

1981-01-01

Results of an analysis of amino acids and hydrocarbons found in the Isua banded iron formation, which contains the oldest known rocks on earth, are discussed. Similarities are pointed out between the relative amino acid abundances of the Isua rocks and those of lichens found on their surfaces, and a lack of substantial racemization indicated by the low D/L ratios in the 3800-million year old rock samples is noted. Experimental results showing the possibility of amino acid diffusion from lichens into the rocks are presented. Comparisons of the Isua rock amino acid D/L ratios with those reported for samples from other regions indicates that none of the Isua amino acids are older than a few tens of thousands to a few hundred thousand years. Analyses of the saturated hydrocarbons of the Isua samples reveals no odd carbon number preference, which may indicate antiquity, however laboratory experiments have shown that amino acids and aromatic and saturated aliphatic hydrocarbons could not have survived the metamorphic history of the Isua rocks. The evidence presented thus suggests that the amino acids and hydrocarbons found are not of the age of the sediments.

Winter Safety Tips for Older Adults

MedlinePlus

... smaller roads. • Stock your car with basic emergency supplies such as: – First aid kid – Blankets – Extra warm clothes – Booster cables – Windshield scraper – Shovel – Rock salt or a bag of sand or cat litter (in case your wheels get stuck) – Water and dried food or canned food (with can ...

Fourteenth workshop geothermal reservoir engineering: Proceedings

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

Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.

1989-01-01

The Fourteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 24--26, 1989. Major areas of discussion include: (1) well testing; (2) various field results; (3) geoscience; (4) geochemistry; (5) reinjection; (6) hot dry rock; and (7) numerical modelling. For these workshop proceedings, individual papers are processed separately for the Energy Data Base.

Fourteenth workshop geothermal reservoir engineering: Proceedings

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

Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.

The Fourteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 24--26, 1989. Major areas of discussion include: (1) well testing; (2) various field results; (3) geoscience; (4) geochemistry; (5) reinjection; (6) hot dry rock; and (7) numerical modelling. For these workshop proceedings, individual papers are processed separately for the Energy Data Base.

Comparison of Proteins in Whole Blood and Dried Blood Spot Samples by LC/MS/MS

NASA Astrophysics Data System (ADS)

Chambers, Andrew G.; Percy, Andrew J.; Hardie, Darryl B.; Borchers, Christoph H.

2013-09-01

Dried blood spot (DBS) sampling methods are desirable for population-wide biomarker screening programs because of their ease of collection, transportation, and storage. Immunoassays are traditionally used to quantify endogenous proteins in these samples but require a separate assay for each protein. Recently, targeted mass spectrometry (MS) has been proposed for generating highly-multiplexed assays for biomarker proteins in DBS samples. In this work, we report the first comparison of proteins in whole blood and DBS samples using an untargeted MS approach. The average number of proteins identified in undepleted whole blood and DBS samples by liquid chromatography (LC)/MS/MS was 223 and 253, respectively. Protein identification repeatability was between 77 %-92 % within replicates and the majority of these repeated proteins (70 %) were observed in both sample formats. Proteins exclusively identified in the liquid or dried fluid spot format were unbiased based on their molecular weight, isoelectric point, aliphatic index, and grand average hydrophobicity. In addition, we extended this comparison to include proteins in matching plasma and serum samples with their dried fluid spot equivalents, dried plasma spot (DPS), and dried serum spot (DSS). This work begins to define the accessibility of endogenous proteins in dried fluid spot samples for analysis by MS and is useful in evaluating the scope of this new approach.

Estimation of Deeper Structure at the Soultz Hot Dry Rock Field by Means of Reflection Method Using 3C AE as Wave Source

NASA Astrophysics Data System (ADS)

Soma, N.; Niitsuma, H.; Baria, R.

1997-12-01

We investigate the deep subsurface structure below the artificial reservoir at the Soultz Hot Dry Rock (HDR) site in France by a reflection method which uses acoustic emission (AE) as a wave source. In this method, we can detect reflected waves by examining the linearity of a three-dimensional hodogram. Additionally for imaging a deep subsurface structure, we employ a three-dimensional inversion with a restriction of wave polarization angles and with a compensation for a heterogeneous source distribution.¶We analyzed 101 AE wave forms observed at the Soultz site during the hydraulic testing in 1993. Some deep reflectors were revealed by this method. The bottom of the artificial reservoir that is presumed from all of the AE locations in 1993 was delineated at the depth of about 3900 m as a reflector. Other deeper reflectors were detected below the reservoir, which would not have been detected using conventional methods. Furthermore these reflectors agreed with the results of the tri-axial drill-bit VSP (Asanuma et al., 1996).

FY12 ARRA-NRAP Report – Studies to Support Risk Assessment of Geologic Carbon Sequestration

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

Cantrell, Kirk J.; Shao, Hongbo; Thompson, C. J.

2011-09-27

This report summarizes results of research conducted during FY2012 to support the assessment of environmental risks associated with geologic carbon dioxide (CO2) sequestration and storage. Several research focus areas are ongoing as part of this project. This includes the quantification of the leachability of metals and organic compounds from representative CO2 storage reservoir and caprock materials, the fate of metals and organic compounds after release, and the development of a method to measure pH in situ under supercritical CO2 (scCO2) conditions. Metal leachability experiments were completed on 6 different rock samples in brine in equilibrium with scCO2 at representative geologicmore » reservoir conditions. In general, the leaching of RCRA metals and other metals of concern was found to be limited and not likely to be a significant issue (at least, for the rocks tested). Metals leaching experiments were also completed on 1 rock sample with scCO2 containing oxygen at concentrations of 0, 1, 5, and 10% to simulate injection of CO2 originating from the oxy-fuel combustion process. Significant differences in the leaching behavior of certain metals were observed when oxygen is present in the CO2. These differences resulted from oxidation of sulfides, release of sulfate, ferric iron and other metals, and subsequent precipitation of iron oxides and some sulfates such as barite. Experiments to evaluate the potential for mobilization of organic compounds from representative reservoir materials and cap rock and their fate in porous media (quartz sand) have been conducted. Results with Fruitland coal and Gothic shale indicate that lighter organic compounds were more susceptible to mobilization by scCO2 compared to heavier compounds. Alkanes demonstrated very low extractability by scCO2. No significant differences were observed between the extractability of organic compounds by dry or water saturated scCO2. Reaction equilibrium appears to have been reached by 96 hours. When the scCO2 was released from the reactor, less than 60% of the injected lighter compounds (benzene, toluene) were transported through dry sand column by the CO2, while more than 90% of the heavier organics were trapped in the sand column. For wet sand columns, most (80% to 100%) of the organic compounds injected into the sand column passed through, except for naphthalene which was substantial removed from the CO2 within the column. A spectrophotometric method was developed to measure pH in brines in contact with scCO2. This method provides an alternative to fragile glass pH electrodes and thermodynamic modeling approaches for estimating pH. The method was tested in simulated reservoir fluids (CO2–NaCl–H2O) at different temperatures, pressures, and ionic strength, and the results were compared with other experimental studies and geochemical models. Measured pH values were generally in agreement with the models, but inconsistencies were present between some of the models.« less

Rock sample brought to earth from the Apollo 12 lunar landing mission

NASA Technical Reports Server (NTRS)

1969-01-01

Astronaut Charles Conrad Jr., commander of the Apollo 12 lunar landing mission, holds two lunar rocks which were among the samples brought back from the Moon by the Apollo 12 astronauts. The samples are under scientific examination in the Manned Spacecraft Center's Lunar Receiving Laboratory.

Detecting Organic Compounds Released from Iron Oxidizing Bacteria using Sample Analysis at Mars (SAM) Like Instrument Protocols

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Popa, R.; Martin, M. G.; Freissinet, C.; Fisk, M. R.; Dworkin, J. P.; Mahaffy, P. R.

2012-01-01

Mars is a planet of great interest for Astrobiology since its past environmental conditions are thought to have been favourable for the emergence life. At present, the Red Planet is extremely cold and dry and the surface is exposed to intense UV and ionizing radiation, conditions generally considered to be incompatible with life as we know it on Earth. It was proposed that the shallow subsurface of Mars, where temperatures can be above freezing and liquid water can exist on rock surfaces, could harbor chemolithoautotrophic bacteria such as the iron oxidizing microorganism Pseudomonas sp. HerB. The Mars Science Laboratory (MSL) mission will provide the next opportunity to carry out in situ measurements for organic compounds of possible biological origin on Mars. One instrument onboard MSL, called the Sample Analysis at Mars (SAM) instrument suite, will carry out a broad and sensitive search for organic compounds in surface samples using either high temperature pyrolysis or chemical extraction followed by gas chromatography mass spectrometry. We present gas chromatograph mass spectrometer (GC/MS) data on crushed olivine rock powders that have been inoculated with Pseudomonas sp. HerB at different concentrations ranging from approx 10(exp 2) to 10(exp 7) cells per gram. The inoculated olivine samples were heated under helium carrier gas flow at 500 C and the pyrolysis products concentrated using a SAM-like hydrocarbon trap set at -20 C followed by trap heating and analysis by GC/Ms. In addition, the samples were also extracted using a low temperature "one-pot" chemical extraction technique using N-methyl, N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) as the silylating agent prior to GC/MS analysis. We identified several aldehydes, thiols, and alkene nitriles after pyrolysis GC/MS analysis of the bacteria that were not found in the olivine control samples that had not been inoculated with bacteria. The distribution of pyrolysis products extracted from the bacteria was clearly distinct from similar GC/MS analyses of the carbonaceous meteorite Murchison that was dominated by sulfur containing aromatic compounds. A similar comparison, if organic compounds are detected by SAM on Mars, could be useful to help discriminate between meteoritic or biological origins.

The effects of pressure, temperature, and pore water on velocities in Westerly granite. [for seismic wave propagation

NASA Technical Reports Server (NTRS)

Spencer, J. W., Jr.; Nur, A. M.

1976-01-01

A description is presented of an experimental assembly which has been developed to conduct concurrent measurements of compressional and shear wave velocities in rocks at high temperatures and confining pressures and with independent control of the pore pressure. The apparatus was used in studies of the joint effects of temperature, external confining pressure, and internal pore water on sonic velocities in Westerly granite. It was found that at a given temperature, confining pressure has a larger accelerating effect on compressional waves in dry rock, whereas at a given confining pressure, temperature has a larger retarding effect on shear waves.

Chemical composition of crystalline rock fragments from Luna 16 and Luna 20 fines

NASA Technical Reports Server (NTRS)

Cimbalnikova, A.; Palivcova, M.; Frana, J.; Mastalka, A.

1977-01-01

The chemical composition (bulk, rare earth, and trace elements) of the Luna 16 mare regolith and luna 20 highland regolith is discussed. The rock samples considered are 14 basaltic rock fragments (Luna 16) and 13 rock fragments of the ANT suite (Luna 20). On the basis of bulk composition, two types of basaltic rocks have been differentiated and defined in the Luna 16 regolith: mare basalts (fundamental crystalline rocks of Mare Fecunditatis) and high-alumina basalts. The bulk analyses of rock fragments of the ANT suite also enabled distinction of two rock types: anorthositic norites and troctolites and/or spinal-troctolites (the most abundant crystalline rocks of the highland region, the landing site of luna 20), and anorthosites. The chemical compositions of Luna 16 and Luna 20 regolith samples are compared. Differences in the chemistry of the Luna 16 mare regolith and that of mare basalts are discussed. The chemical affinity between the Luna 20 highland regolith and (a) anorthositic norites and (b) troctolites and/or spinel-troctolites has been ascertained.

Comparison of Two Methods for Determination of Strontium Isotopes in Pore Water at Yucca Mountain, Nevada

NASA Astrophysics Data System (ADS)

Marshall, B. D.; Futa, K.; Scofield, K. M.

2002-12-01

The proposed radioactive waste repository at Yucca Mountain, Nevada would be constructed in the high-silica rhyolite member of the Topopah Spring Tuff, an ash-flow tuff within the ~500-m-thick unsaturated zone. Dry-drilled rock cores from this unit have been packaged to preserve their water content. Two methods have been used to extract the strontium contained in the pore water for isotopic measurements. In the first method, samples of dried core were crushed, and the 0.25 to 2.4 mm size fractions were leached with ultra-pure water for about 1 hour to dissolve the salts left behind by the evaporated pore water. Concentrations of strontium in the pore water were calculated from determinations of porosity and saturation on adjacent core and the measured strontium concentration in the leachate. In the second method, pore water was extracted from sealed core using an ultracentrifuge, minimizing evaporation of water from the core at all steps in the process. The centrifugation of 150 to 200 g of welded tuff at 15,000 rpm for 6 hours typically results in the recovery of as much as 3 ml of pore water for analysis. Strontium isotope compositions were determined by thermal ionization mass spectrometry; 87Sr /86Sr ratios have a reproducibility of 0.00005. The ranges of 87Sr/86Sr ratios determined by the two methods are identical: 0.71215 to 0.71267 in the leachates (n = 35) and 0.71214 to 0.71266 in the extracted pore waters (n = 21). However, the calculated strontium concentrations in the leachates average 300 μg/L, whereas those in the extracted pore water average 1440 μg/L, indicating that a substantial portion of the pore-water salts remain in the crushed rock after leaching. The strontium data determined on extracted pore water shows that the leaching of pore-water salts results in accurate 87Sr/86Sr, but that a substantial correction to the strontium concentration is required due to the inefficiency of the leaching procedure and the small pore sizes in the welded tuffs. The strontium isotope data obtained on leachates can be used to constrain models of water-rock interaction and estimates of travel times in the unsaturated zone.

Rare Earth Element and Trace Element Data Associated with Hydrothermal Spring Reservoir Rock, Idaho

DOE Data Explorer

Quillinan, Scott; Bagdonas, Davin

2017-06-22

These data represent rock samples collected in Idaho that correspond with naturally occurring hydrothermal samples that were collected and analyzed by INL (Idaho Falls, ID). Representative samples of type rocks were selected to best represent the various regions of Idaho in which naturally occurring hydrothermal waters occur. This includes the Snake River Plain (SRP), Basin and Range type structures east of the SRP, and large scale/deep seated orogenic uplift of the Sawtooth Mountains, ID. Analysis includes ICP-OES and ICP-MS methods for Major, Trace, and REE concentrations.

[Comparison of sulfur fumigation processing and direct hot air heating technology on puerarin contents and efficacy of Puerariae Thomsonii Radix].

PubMed

Yu, Hong-Li; Zhang, Qian; Jin, Yang-Ping; Wang, Kui-Long; Lu, Tu-Lin; Li, Lin

2016-07-01

In order to compare the effect of sulfur fumigation processing and direct hot air heating technology on puerarin contents and efficacy of Puerariae Thomsonii Radix, the fresh roots of Pueraria thomsonii were cut into small pieces and prepared into direct sunshine drying samples, direct hot air drying samples, and sulfur fumigation-hot air drying samples. Moisture contents of the samples were then determined. The puerarin contents of different samples were compared by HPLC method. Moreover, the models of drunkenness mice were established, and then with superoxide dismutase (SOD) content as the index, aqueous decoction extracts of Puerariae Thomsonii Radix samples with sulfur fumigation processing and non-sulfur fumigation processing methods were administrated by ig; the effects of sulfur fumigation on contents of SOD in mice liver and serum were determined, and the sulfur fumigation samples and non-sulfur fumigation samples were investigated for moth and mildew under different packaging and storage conditions. Results showed that the sulfur fumigation samples significantly changed the puerarin content from Puerariae Thomsonii Radix. The content of puerarin was decreased gradually when increasing the times of sulfur fumigation and amount of sulfur. SOD content in drunken mice liver and serum was significantly decreased when increasing the times of sulfur fumigation, showing significant difference with both direct sunshine drying group and direct hot air drying group. Moth and mildew were not found in the sulfur fumigation samples and direct hot air drying samples whose moisture contents were lower than the limit in Pharmacopoeia. Research showed that sulfur fumigation can significantly reduce the content of main active ingredients and reduce the efficacy of Puerariae Thomsonii Radix, indicating that the quality of Puerariae Thomsonii Radix was significantly decreased after sulfur fumigation. However, the contents of the main active ingredients, efficacy and storage results of the direct hot air drying samples were similar to those in direct sunshine drying samples, so the hot air drying process was a nice drying technology which could be promoted for use. Copyright© by the Chinese Pharmaceutical Association.