Zirconium

USGS Publications Warehouse

Bedinger, G.M.

2013-01-01

Zirconium is the 20th most abundant element in the Earth’s crust. It occurs in a variety of rock types and geologic environments but most often in igneous rocks in the form of zircon (ZrSiO4). Zircon is recovered as a coproduct of the mining and processing of heavy mineral sands for the titanium minerals ilmenite and rutile. The sands are formed by the weathering and erosion of rock containing zircon and titanium heavy minerals and their subsequent concentration in sedimentary systems, particularly in coastal environments. A small quantity of zirconium, less than 10 kt/a (11,000 stpy), compared with total world production of 1.4 Mt (1.5 million st) in 2012, was derived from the mineral baddeleyite (ZrO2), produced from a single source in Kovdor, Russia.

Map showing structure of the Mississippi Valley Graben in the vicinity of New Madrid, Missouri

USGS Publications Warehouse

Wheeler, Russell L.; Rhea, Susan; Dart, Richard L.

1994-01-01

This is one of a series of five seismotectonic maps of the seismically active New Madrid area in southeast Missouri and adjacent parts of Arkansas, Kentucky, and Tennessee (table 1). We cannot legibly show all the seismotectonic data on a single map, therefore each of the five maps in this series groups a different type of related information. Rhea and others (1994) summarized the background and purpose of the seismotectonic map folio. The different types of data shown on this map are described in table 2. Except for a few exposed faults, all structures shown on the map are in Paleozoic sedimentary rocks of the midcontinent or underlying metamorphic and igneous basement rocks of presumed Precambrian age (Dart, 1992; Muehlberger, 1992). Edge of Mississippi Embayment, as shown on the map, marks the contact between gently dipping, exposed Paleozoic rocks to the northwest (Anderson and others, 1979) and unconformably overlying, flat or gently dipping Mesozoic and Cenozoic strata of the embayment to the southeast.

The effect of organic acids on wettability of sandstone and carbonate rocks

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

Mwangi, Paulina; Brady, Patrick V.; Radonjic, Mileva

This paper examines the role of crude oil’s organic acid surface active compounds (SAC) in determining the reservoir wettability over a range of salinities and temperatures. To isolate the effects of individual SACs, this project used model oil mixtures of pure decane and single SACs to represent the oleic phase. Due to the large number of experiments in this study, we used wettability measurement method by the modified flotation technique (MFT) to produce fast, reliable, and quantitative results. The results showed that oil wetting by decane increased with temperature for carbonate rocks. Sandstones oil wetting showed little temperature dependency. Themore » presence of long-chained acids in decane increased oil wetting in sandstone and carbonate rocks as salinity was lowered, while the short-chained acid increased water wetting under the same conditions. The effect of organic acids on wettability was slightly enhanced with increasing temperature for all rock types.« less

The effect of organic acids on wettability of sandstone and carbonate rocks

DOE PAGES

Mwangi, Paulina; Brady, Patrick V.; Radonjic, Mileva; ...

2018-02-21

This paper examines the role of crude oil’s organic acid surface active compounds (SAC) in determining the reservoir wettability over a range of salinities and temperatures. To isolate the effects of individual SACs, this project used model oil mixtures of pure decane and single SACs to represent the oleic phase. Due to the large number of experiments in this study, we used wettability measurement method by the modified flotation technique (MFT) to produce fast, reliable, and quantitative results. The results showed that oil wetting by decane increased with temperature for carbonate rocks. Sandstones oil wetting showed little temperature dependency. Themore » presence of long-chained acids in decane increased oil wetting in sandstone and carbonate rocks as salinity was lowered, while the short-chained acid increased water wetting under the same conditions. The effect of organic acids on wettability was slightly enhanced with increasing temperature for all rock types.« less

Integration of NASA/GSFC and USGS Rock Magnetic Databases.

NASA Astrophysics Data System (ADS)

Nazarova, K. A.; Glen, J. M.

2004-05-01

A global Magnetic Petrology Database (MPDB) was developed and continues to be updated at NASA/Goddard Space Flight Center. The purpose of this database is to provide the geomagnetic community with a comprehensive and user-friendly method of accessing magnetic petrology data via the Internet for a more realistic interpretation of satellite (as well as aeromagnetic and ground) lithospheric magnetic anomalies. The MPDB contains data on rocks from localities around the world (about 19,000 samples) including the Ukranian and Baltic Shields, Kamchatka, Iceland, Urals Mountains, etc. The MPDB is designed, managed and presented on the web as a research oriented database. Several database applications have been specifically developed for data manipulation and analysis of the MPDB. The geophysics unit at the USGS in Menlo Park has over 17,000 rock-property data, largely from sites within the western U.S. This database contains rock-density and rock-magnetic parameters collected for use in gravity and magnetic field modeling, and paleomagnetic studies. Most of these data were taken from surface outcrops and together they span a broad range of rock types. Measurements were made either in-situ at the outcrop, or in the laboratory on hand samples and paleomagnetic cores acquired in the field. The USGS and NASA/GSFC data will be integrated as part of an effort to provide public access to a single, uniformly maintained database. Due to the large number of data and the very large area sampled, the database can yield rock-property statistics on a broad range of rock types; it is thus applicable to study areas beyond the geographic scope of the database. The intent of this effort is to provide incentive for others to further contribute to the database, and a tool with which the geophysical community can entertain studies formerly precluded.

Petrologic and Oxygen-Isotopic Investigations of Eucritic and Anomalous Mafic Achondrites

NASA Technical Reports Server (NTRS)

Mittlefehldt, D. W.; Greenwood, R. C.; Peng, Z. X.; Ross, D. K.; Berger, E. L.; Barrett, T. J.

2016-01-01

The most common asteroidal igneous meteorites are eucrite-type basalts and gabbros rocks composed of ferroan pigeonite and augite, calcic plagioclase, silica, ilmenite, troilite, Ca-phosphate, chromite and Fe-metal. These rocks are thought to have formed on a single asteroid along with howardites and diogenites (HEDs). However, Northwest Africa (NWA) 011 is mineralogically identical to eucrites, but has an O-isotopic composition distinct from them and was derived from a different asteroid. Modern analyses with higher precision have shown that some eucrites have smaller O-isotopic differences that are nevertheless well-resolved from the group mean.

A new simplified method for measuring the permeability characteristics of highly porous media

NASA Astrophysics Data System (ADS)

Qin, Yinghong; Zhang, Mingyi; Mei, Guoxiong

2018-07-01

Fluid flow through highly porous media is important in a variety of science and technology fields, including hydrology, chemical engineering, convections in porous media, and others. While many methods have been available to measure the permeability of tight solid materials, such as concrete and rock, the technique for measuring the permeability of highly porous media is limited (such as gravel, aggregated soils, and crushed rock). This study proposes a new simplified method for measuring the permeability of highly porous media with a permeability of 10-8-10-4 m2, using a Venturi tube to gauge the gas flowing rate through the sample. Using crushed rocks and glass beads as the test media, we measure the permeability and inertial resistance factor of six types of single-size aggregate columns. We compare the testing results with the published permeability and inertial resistance factor of crushed rock and of glass beads. We found that in a log-log graph, the permeability and inertial resistance factor of a single-size aggregate heap increases linearly with the mean diameter of the aggregate. We speculate that the proposed simplified method is suitable to efficiently test the permeability and inertial resistance factor of a variety of porous media with an intrinsic permeability of 10-8-10-4 m2.

The Nasa earth resources spectral information system: A data compilation, first supplement

NASA Technical Reports Server (NTRS)

Leeman, V.

1972-01-01

The NASA Earth Resources Spectral Information System and the information contained therein are described. It is intended to be used as a supplement to the NASA Earth Resources Spectral Information System: A Data Compilation, N72-28366. This supplement includes approximately 500 rock and mineral, 100 soil, and 30 vegetation bidirectional and directional reflectance, transmittance, emittance, and degree-of-polarization curves in the optical region from 0.2 to 22.0 microns. The data have been categorized by subject and each curve plotted on a single graph. For some rocks and minerals, all curves of the same type, differing only in particle size, have been plotted on one grid as a composite plot. Each graph, composite or single, is fully titled to indicate curve source and is indexed by subject to facilitate user retrieval.

The bridge permeameter; An alternative method for single-phase, steady-state permeability measurements

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

Graf, D.C.; Warpinski, N.R.

Laboratory measurements of single-phase, steady-state permeability of porous rock are important for a number of different applications. The oil and gas industry uses permeability data as a key indicator of the producability of a hydrocarbon reservoir; effective containment of large volumes of oil in underground salt caverns is directly dependent upon the permeability of the adjacent cavern walls; and safe, long term underground isolation of radioactive and hazardous waste is contingent upon the flow and transport characteristics of the surrounding geologic formations. An alternative method for measuring single-phase, steady-state permeability of porous rock is presented. The use of troublesome andmore » expensive mass flow meters is eliminated and replaced with a bridge configuration of flow resistors. Permeability values can be determined directly from differential pressures across the bridge network, resulting in potentially significant cost savings and simplification for conducting these types of measurements. Results from the bridge permeameter are compared with results obtained using conventional methods.« less

Evaluation of Five Sedimentary Rocks Other Than Salt for Geologic Repository Siting Purposes

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

Croff, A.G.; Lomenick, T.F.; Lowrie, R.S.

The US Department of Energy (DOE), in order to increase the diversity of rock types under consideration by the geologic disposal program, initiated the Sedimary ROck Program (SERP), whose immediate objectiv eis to evaluate five types of secimdnary rock - sandstone, chalk, carbonate rocks (limestone and dolostone), anhydrock, and shale - to determine the potential for siting a geologic repository. The evaluation of these five rock types, together with the ongoing salt studies, effectively results in the consideration of all types of relatively impermeable sedimentary rock for repository purposes. The results of this evaluation are expressed in terms of amore » ranking of the five rock types with respect to their potential to serve as a geologic repository host rock. This comparative evaluation was conducted on a non-site-specific basis, by use of generic information together with rock evaluation criteria (RECs) derived from the DOE siting guidelines for geologic repositories (CFR 1984). An information base relevant to rock evaluation using these RECs was developed in hydrology, geochemistry, rock characteristics (rock occurrences, thermal response, rock mechanics), natural resources, and rock dissolution. Evaluation against postclosure and preclosure RECs yielded a ranking of the five subject rocks with respect to their potential as repository host rocks. Shale was determined to be the most preferred of the five rock types, with sandstone a distant second, the carbonate rocks and anhydrock a more distant third, and chalk a relatively close fourth.« less

Multispectral Imaging from Mars PATHFINDER

NASA Technical Reports Server (NTRS)

Ferrand, William H.; Bell, James F., III; Johnson, Jeffrey R.; Bishop, Janice L.; Morris, Richard V.

2007-01-01

The Imager for Mars Pathfinder (IMP) was a mast-mounted instrument on the Mars Pathfinder lander which landed on Mars Ares Vallis floodplain on July 4, 1997. During the 83 sols of Mars Pathfinders landed operations, the IMP collected over 16,600 images. Multispectral images were collected using twelve narrowband filters at wavelengths between 400 and 1000 nm in the visible and near infrared (VNIR) range. The IMP provided VNIR spectra of the materials surrounding the lander including rocks, bright soils, dark soils, and atmospheric observations. During the primary mission, only a single primary rock spectral class, Gray Rock, was recognized; since then, Black Rock, has been identified. The Black Rock spectra have a stronger absorption at longer wavelengths than do Gray Rock spectra. A number of coated rocks have also been described, the Red and Maroon Rock classes, and perhaps indurated soils in the form of the Pink Rock class. A number of different soil types were also recognized with the primary ones being Bright Red Drift, Dark Soil, Brown Soil, and Disturbed Soil. Examination of spectral parameter plots indicated two trends which were interpreted as representing alteration products formed in at least two different environmental epochs of the Ares Vallis area. Subsequent analysis of the data and comparison with terrestrial analogs have supported the interpretation that the rock coatings provide evidence of earlier martian environments. However, the presence of relatively uncoated examples of the Gray and Black rock classes indicate that relatively unweathered materials can persist on the martian surface.

Magnetic and mineralogical properties of salt rocks from the Zechstein of the Northern German Basin

NASA Astrophysics Data System (ADS)

Heinrich, Frances C.; Schmidt, Volkmar; Schramm, Michael; Mertineit, Michael

2017-03-01

Magnetic properties of rocks are often studied to characterize composition and fabric of rocks. For salt rocks, the basic relationships between their magnetic properties and composition, which are necessary to interpret rock magnetic data, are not yet established. Therefore, we studied different types of natural salt rock and pure salt minerals. We measured their magnetic properties (magnetic susceptibility, isothermal remanent magnetization acquisition curves, first-order reversal curve diagrams and temperature-dependent magnetic susceptibility) and used analytical methods such as microscopy, X-ray diffraction and inductively coupled plasma atomic emission spectroscopy to understand the relationship between magnetic properties and mineralogy. Salt rocks mainly consist of the diamagnetic minerals halite, carnallite, sylvine and anhydrite with negative magnetic susceptibilities. The magnetic susceptibilities of pure synthetic NaCl and KCl single crystals, show values of -14.5 × 10-6 and -13.5 × 10-6 SI, respectively. In contrast, in natural salt rocks higher magnetic susceptibility values were measured. The magnetic susceptibility of the samples investigated in this study shows a general increase from light rock salt (maximum -10 × 10-6 SI) over carnallitite (maximum 134 × 10-6 SI) to red sylvinite (maximum 270 × 10-6 SI). Whole rock analyses suggest that increased magnetic susceptibility can be attributed to paramagnetic and ferromagnetic minerals that are contained within the insoluble residue. The magnetic susceptibility is mainly controlled by magnetite and phyllosilicates. Its measurement can therefore be used to detect subtle changes in the content of these minerals.

Fundamental Research on Percussion Drilling: Improved rock mechanics analysis, advanced simulation technology, and full-scale laboratory investigations

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

Michael S. Bruno

This report summarizes the research efforts on the DOE supported research project Percussion Drilling (DE-FC26-03NT41999), which is to significantly advance the fundamental understandings of the physical mechanisms involved in combined percussion and rotary drilling, and thereby facilitate more efficient and lower cost drilling and exploration of hard-rock reservoirs. The project has been divided into multiple tasks: literature reviews, analytical and numerical modeling, full scale laboratory testing and model validation, and final report delivery. Literature reviews document the history, pros and cons, and rock failure physics of percussion drilling in oil and gas industries. Based on the current understandings, a conceptualmore » drilling model is proposed for modeling efforts. Both analytical and numerical approaches are deployed to investigate drilling processes such as drillbit penetration with compression, rotation and percussion, rock response with stress propagation, damage accumulation and failure, and debris transportation inside the annulus after disintegrated from rock. For rock mechanics modeling, a dynamic numerical tool has been developed to describe rock damage and failure, including rock crushing by compressive bit load, rock fracturing by both shearing and tensile forces, and rock weakening by repetitive compression-tension loading. Besides multiple failure criteria, the tool also includes a damping algorithm to dissipate oscillation energy and a fatigue/damage algorithm to update rock properties during each impact. From the model, Rate of Penetration (ROP) and rock failure history can be estimated. For cuttings transport in annulus, a 3D numerical particle flowing model has been developed with aid of analytical approaches. The tool can simulate cuttings movement at particle scale under laminar or turbulent fluid flow conditions and evaluate the efficiency of cutting removal. To calibrate the modeling efforts, a series of full-scale fluid hammer drilling tests, as well as single impact tests, have been designed and executed. Both Berea sandstone and Mancos shale samples are used. In single impact tests, three impacts are sequentially loaded at the same rock location to investigate rock response to repetitive loadings. The crater depth and width are measured as well as the displacement and force in the rod and the force in the rock. Various pressure differences across the rock-indentor interface (i.e. bore pressure minus pore pressure) are used to investigate the pressure effect on rock penetration. For hammer drilling tests, an industrial fluid hammer is used to drill under both underbalanced and overbalanced conditions. Besides calibrating the modeling tool, the data and cuttings collected from the tests indicate several other important applications. For example, different rock penetrations during single impact tests may reveal why a fluid hammer behaves differently with diverse rock types and under various pressure conditions at the hole bottom. On the other hand, the shape of the cuttings from fluid hammer tests, comparing to those from traditional rotary drilling methods, may help to identify the dominant failure mechanism that percussion drilling relies on. If so, encouraging such a failure mechanism may improve hammer performance. The project is summarized in this report. Instead of compiling the information contained in the previous quarterly or other technical reports, this report focuses on the descriptions of tasks, findings, and conclusions, as well as the efforts on promoting percussion drilling technologies to industries including site visits, presentations, and publications. As a part of the final deliveries, the 3D numerical model for rock mechanics is also attached.« less

Mantle sources and origin of the Middle Paleoproterozoic Jatulian Large Igneous Province of the Fennoscandian shield: evidence from isotope geochemical data on the Kuetsjarvi volcanics, Kola Craton

NASA Astrophysics Data System (ADS)

Bogina, Maria; Zlobin, Valeriy; Chistyakov, Alexeii; Evgenii, Sharkov

2014-05-01

Paleoproterozoic is one of the most important stages in the Earth's evolution as marking a cardinal change in a style of tectonomagmatic processes at 2.2-2.0 Ga, which corresponds to the formation of the Jatulian Large Igneous Province at the Fennoscandian Shield. The fragment of this province is represented by the volcanics of the Kuetsjarvi Group in the Kola Craton. These rocks differ in the extremely wide rock diversity and prominent role of alkaline rocks, the extremely rare rocks in the Precambrian. The rocks of the group are subdivided into the alkaline and tholeiitic basaltic series. The tholeiites are highly fractionated (mg# 38) high-Ti rocks enriched in HFSE. The alkaline series show wider mg# variations (32-52), which is inconsistent with a single fractionation sequence of these series. All rocks have high HFSE, at extremely wide LILE variations. Tholeiites show moderate LREE fractionation pattern at practically flat HREE: La/YbN = 3.6-4.5; La/SmN = 2.2-2.4, Gd/YbN = 1.5-1.7 and slight Eu anomaly (Eu/Eu* = 0.80-0.85). The alkaline rocks display much more fractionated LREE and fractionated HREE (La/YbN = 43.9-5.8; La/SmN = 2.2-2.4, Gd/YbN = 2.04-3.92) patterns at Eu anomaly varying from 0.53 to 1. The spidergrams of both series reveal negative Nb and Sr anomalies at sign-variable Ti anomaly. The alkaline rocks are enriched relative to tholeiites in U, Th, and Nb. Examination of behavior of incompatible trace elements offers an opportunity to compare the conditions of generation of parental mantle magmas of the studied series. In particular, the tholeiitic basalts have higher Zr/Nb ratios than the alkaline rocks, which in combination with their lower La/Yb ratios indicates their formation under the higher melting degree of mantle source as compared to the alkaline rocks. Simultaneous increase in Ce/Y ratio in the alkaline rocks may indicate their formation at greater depths. Tholeiitic basalts have lower Nb/U ratio, which testifies some crustal contamination of the melts. In addition, they have low Ti/Y (323-449) ratios and high Lu/Hf (0.11-0.16), which is typical of the rocks formed by melting of spinel peridotites. The alkaline basalts were derived from a deeper garnet-bearing mantle source (Ti/Y = 640-1140, Lu/Hf = 0.03-0.05). Isotope-geochemical study showed that these rocks have very similar Nd isotope composition ((eNd (2200) = +1.5 in the alkaline basalt and +1.9 in the tholeiites). It was found that the studied alkaline rocks are similar in composition to the OIB-type Tristan da Kunha basalts, while tholeiites are closer to the high-Ti rocks of the Parana plateau, which experienced significant lithospheric contribution. Obtained data confirm the within-plate setting at the Jatulian stage of the Fennoscandian Shield. The Kutesjarvi Group consists of two rock types: OIB-type alkaline and E-MORB-type tholeiitic, which is typical of most Phanerozoic large igneous provinces. However, unlike the latters, the rocks of this area were too much tectonized and eroded to compile a systematic sequence. But, the Kuetsjarvi Group may be considered as the fragment of the oldest large igneous province.

10 CFR 960.3-1-2 - Diversity of rock types.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false Diversity of rock types. 960.3-1-2 Section 960.3-1-2... NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-2 Diversity of rock types. Consideration... sites for characterization shall have different types of host rock. ...

10 CFR 960.3-1-2 - Diversity of rock types.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 4 2013-01-01 2013-01-01 false Diversity of rock types. 960.3-1-2 Section 960.3-1-2... NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-2 Diversity of rock types. Consideration... sites for characterization shall have different types of host rock. ...

10 CFR 960.3-1-2 - Diversity of rock types.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 4 2014-01-01 2014-01-01 false Diversity of rock types. 960.3-1-2 Section 960.3-1-2... NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-2 Diversity of rock types. Consideration... sites for characterization shall have different types of host rock. ...

10 CFR 960.3-1-2 - Diversity of rock types.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 4 2012-01-01 2012-01-01 false Diversity of rock types. 960.3-1-2 Section 960.3-1-2... NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-2 Diversity of rock types. Consideration... sites for characterization shall have different types of host rock. ...

The effect of the Ras homolog gene family (Rho), member A/Rho associated coiled-coil forming protein kinase pathway in atrial fibrosis of type 2 diabetes in rats.

PubMed

Chen, Jinling; Li, Qingqing; Dong, Ruiqing; Gao, Huikuan; Peng, Hui; Wu, Yongquan

2014-09-01

Diabetes mellitus promotes atrial structural remodeling, thereby producing atrial arrhythmogenicity. Atrial arrhythmia can substantially increase the risk of premature death. The aim of this study was to investigate the role of Ras homolog gene family, member A (RhoA)/Rho associated coiled-coil forming protein kinase (ROCK) in atrial fibrosis in diabetic hearts, and the effects of fasudil hydrochloride hydrate on atrial fibrosis. An eight-week-old male Sprague-Dawley rat model of type 2 diabetes was established using a high-fat diet combined with streptozotocin [30 mg/kg, once, intraperitoneal (i.p.)]. Animals were randomly divided into three groups: Control rats, untreated diabetic rats that received vehicle, and treated diabetic rats that received Rho kinase inhibitor fasudil hydrochloride hydrate (10 mg/kg/day, i.p., for 14 weeks). The morphological features of atrial fibrosis were observed using Masson staining. The mRNA expression levels of RhoA, ROCK1, ROCK2, type-I and type-III procollagen were assessed with quantitative polymerase chain reaction. The protein levels of RhoA, ROCK1 and ROCK2 were evaluated using western blot analysis. The atria of untreated diabetic rats showed evident atrial fibrosis as compared to the control rats; the mRNA expression levels of RhoA, ROCK1, ROCK2, type-I and type-III procollagen were upregulated; and the protein levels of RhoA, ROCK1 and ROCK2 were increased. The treatment with fasudil hydrochloride hydrate significantly reduced atrial fibrosis, mRNA levels of RhoA, ROCK1, ROCK2, type-I and type-III procollagen, and the protein levels of RhoA, ROCK1 and ROCK2. The results suggested that RhoA/ROCK was involved in atrial fibrosis, and that fasudil hydrochloride hydrate ameliorates atrial fibrosis through the RhoA/ROCK pathway in rats with type 2 diabetes.

Nitrogen release from rock and soil under simulated field conditions

USGS Publications Warehouse

Holloway, J.M.; Dahlgren, R.A.; Casey, W.H.

2001-01-01

A laboratory study was performed to simulate field weathering and nitrogen release from bedrock in a setting where geologic nitrogen has been suspected to be a large local source of nitrate. Two rock types containing nitrogen, slate (1370 mg N kg-1) and greenstone (480 mg N kg-1), were used along with saprolite and BC horizon sand from soils derived from these rock types. The fresh rock and weathered material were used in batch reactors that were leached every 30 days over 6 months to simulate a single wet season. Nitrogen was released from rock and soil materials at rates between 10-20 and 10-19 mo1 N cm-2 s-1. Results from the laboratory dissolution experiments were compared to in situ soil solutions and available mineral nitrogen pools from the BC horizon of both soils. Concentrations of mineral nitrogen (NO3- + NH4+) in soil solutions reached the highest levels at the beginning of the rainy season and progressively decreased with increased leaching. This seasonal pattern was repeated for the available mineral nitrogen pool that was extracted using a KCl solution. Estimates based on these laboratory release rates bracket stream water NO3-N fluxes and changes in the available mineral nitrogen pool over the active leaching period. These results confirm that geologic nitrogen, when present, may be a large and reactive pool that may contribute as a non-point source of nitrate contamination to surface and ground waters. ?? 2001 Elsevier Science B.V. All rights reserved.

Environmental effects of hydrothermal alteration and historical mining on water and sediment quality in Central Colorado

USGS Publications Warehouse

Church, S.E.; Fey, D. L.; Klein, T.L.; Schmidt, T.S.; Wanty, R.B.; deWitt, E.H.; Rockwell, B.W.; San, Juan C.A.

2009-01-01

The U.S. Geological Survey conducted an environmental assessment of 198 catchments in a 54,000-km2 area of central Colorado, much of which is on Federal land. The Colorado Mineral Belt, a northeast-trending zone of historical base- and precious-metal mining, cuts diagonally across the study area. The investigation was intended to test the hypothesis that degraded water and sediment quality are restricted to catchments in which historical mining has occurred. Water, streambed sediment, and aquatic insects were collected from (1) catchments underlain by single lithogeochemical units, some of which were hydrothermally altered, that had not been prospected or mined; (2) catchments that contained evidence of prospecting, most of which contain hydrothermally altered rock, but no historical mining; and (3) catchments, all of which contain hydrothermally altered rock, where historical but now inactive mines occur. Geochemical data determined from catchments that did not contain hydrothermal alteration or historical mines met water quality criteria and sediment quality guidelines. Base-metal concentrations from these types of catchments showed small geochemical variations that reflect host lithology. Hydrothermal alteration and mineralization typically are associated with igneous rocks that have intruded older bedrock in a catchment. This alteration was regionally mapped and characterized primarily through the analysis of remote sensing data acquired by the ASTER satellite sensor. Base-metal concentrations among unaltered rock types showed small geochemical variations that reflect host lithology. Base-metal concentrations were elevated in sediment from catchments underlain by hydrothermally altered rock. Classification of catchments on the basis of mineral deposit types proved to be an efficient and accurate method for discriminating catchments that have degraded water and sediment quality. Only about 4.5 percent of the study area has been affected by historical mining, whereas a larger part of the study area is underlain by hydrothermally altered rock that has weathered to produce water and sediment with naturally elevated geochemical baselines. 

Petrology and geochemistry of mafic magmatic rocks from the Sarve-Abad ophiolites (Kurdistan region, Iran): Evidence for interaction between MORB-type asthenosphere and OIB-type components in the southern Neo-Tethys Ocean

NASA Astrophysics Data System (ADS)

Saccani, Emilio; Allahyari, Khalil; Rahimzadeh, Bahman

2014-05-01

The Sarve-Abad (Sawlava) ophiolites crop out in the Main Zagros Thrust Zone and represent remnants of the Mesozoic southern Neo-Tethys Ocean that was located between the Arabian shield and Sanandaj-Sirjan continental block. They consist of several incomplete ophiolitic sequences including gabbroic bodies, a dyke complex, and pillow lava sequences. These rocks generally range from sub-alkaline to transitional character. Mineral chemistry and whole-rock geochemistry indicate that they have compositions akin to enriched-type mid-ocean ridge basalts (E-MORB) and plume-type MORB (P-MORB). Nonetheless, the different depletion degrees in heavy rare earth elements (HREE), which can be observed in both E-MORB like and P-MORB like rocks enable two main basic chemical types of rocks to be distinguished as Type-I and Type-II. Type-I rocks are strongly depleted in HREE (YbN < ~ 6), whereas Type-II rocks are moderately depleted in HREE (YbN > 9.0). Petrogenetic modeling shows that Type-I rocks originated from 7 to 16% polybaric partial melting of a MORB-type mantle source, which was significantly enriched by plume-type components. These rocks resulted from the mixing of variable fractions of melts generated in garnet-facies and the spinel-facies mantle. In contrast, Type-II rocks originated from 5 to 8% partial melting in the spinel-facies of a MORB-type source, which was moderately enriched by plume-type components. A possible tectono-magmatic model for the generation of the southern Neo-Tethys oceanic crust implies that the continental rift and subsequent oceanic spreading were associated with uprising of MORB-type asthenospheric mantle featuring plume-type component influences decreasing from deep to shallow mantle levels. These deep plume-type components were most likely inherited from Carboniferous mantle plume activity that was associated with the opening of Paleo-Tethys in the same area.

Accelerated weathering of carbonate rocks following the 2010 forest wildfire on Mt. Carmel, Israel

NASA Astrophysics Data System (ADS)

Shtober-Zisu, Nurit; Tessler, Naama; Tsatskin, Alexander; Greenbaum, Noam

2015-04-01

Massive destruction of carbonate rocks occurred on the slopes of Mt. Carmel, during the severe forest fire in 2010. The bedrock surfaces exhibited extensive exfoliation into flakes and spalls covering up to 80%-100% of the exposed rocks; detached boulders were totally fractured or disintegrated. The fire affected six carbonate units -- various types of chalk, limestone, and dolomite. The burned flakes show a consistent tendency towards flatness, in all lithologies, as 85%-95% of the flakes were detached in the form of blades, plates, and slabs. The effects of the fire depend to a large extent on the rocks' physical properties and vary with lithology: the most severe response was found in the chalk formations which are covered by calcrete (Nari crusts). These rocks reacted by extreme exfoliation, at an average depth of 7.7 to 9.6 cm and a maximum depth of 20 cm. The flakes formed in chalk were thicker, longer, and wider than those of limestone or dolomite formations. Moreover, the chalk outcrops were exfoliated in a laminar structure, one above the other, to a depth of 10 cm and more. Their shape also tended to be blockier or rod-like. In contrast, the limestone flakes were the thinnest, with 99% of them shaped like blades and plates. Scorched and blackened faces under the upper layer of spalls provided strong evidence that chalk breakdown took place at an early stage of the fire. The extreme response of the chalks can be explained by the laminar structure of the Nari, which served as planes of weakness for the rock destruction. Three years after the fire, the rocks continue to exfoliate and break down internally. As the harder surface of the Nari was removed, the more brittle underlying chalk is exposed to erosion. If fires can obliterate boulders in a single wildfire event, it follows that wildfires may serve as limiting agents in the geomorphic evolution of slopes. However, it is difficult to estimate the frequency of high-intensity fires in the Carmel region over the past 2-3 million years. It is even harder to assess the frequency of fires (and the destruction) of a single rock outcrop. Our findings show that rock outcrop may lose even 20 cm of its thickness in a single fire. This value, if accounted to the long run, can be responsible for a high percentage of the total denudation rate and therefore, in the mountainous carbonate slopes of the Mediterranean region, wildland fires may serve as extremely important factors in landscape evolution.

Steady as a rock: Biogeomorphic influence of nurse rocks and slope processes on kūpaoa (Dubautia menziesii) shrubs in Haleakalā Crater (Maui, Hawai'i)

NASA Astrophysics Data System (ADS)

Pérez, Francisco L.

2017-10-01

This study examines biogeomorphic interactions between nurse rocks, slope processes, and 300 kūpaoa (Dubautia menziesii) shrubs in Haleakalā Crater (Maui, Hawai'i). Research objectives were to: assess the association of kūpaoa with substrates upslope and downslope of plants, and proximity to the closest rock uphill; contrast shrub/substrate relationships with site frequency of sediment types; measure surface soil shear-strength and compressibility on 50 paired locations near boulders; and investigate the aggregation characteristics and spatial patterns of kūpaoa in relation to rock and substrate variation. Data analyzed came from three 100-plant surveys at 3 sites: a plant census at 2720-2975 m altitude, and wandering-quarter transects (WQTs) across two areas (2610-2710 m); ground sediment cover was estimated along four phototransects on these sites. Data for the three 100-plant surveys included substrate type-outcrops, blocks, cobbles, pebbles, exposed soil, organic litter-upslope from each plant, and distance to the largest rock upslope. The two surveys examined along WQTs included substrate type found downslope from kūpaoa, plant height, plant diameters across and along the slope, and distance between successively censused plants. Most plants grew downslope of nurse rocks; > 74% were adjacent to blocks or outcrops, and > 17% near cobbles. Plants showed avoidance for finer substrates; only 5.3% and 2.7% grew on/near bare soils and pebbles, respectively. About 92% of kūpaoa were ≤ 10 cm downslope of rocks; > 89% grew ≤ 2 cm away, and 83% in direct contact with a rock. Some seedlings also grew on pukiawe (Leptecophylla tameiameiae) nurse plants. Several stable rock microsites protected plants from disturbance by slope processes causing debris shift. Site sediments were significantly finer than substrates near plants; shrubs grew preferentially adjacent to boulders > 20 cm wide, which were more common near plants than across sites. Soils downslope of 50 boulders-mean 41.3 cm-showed higher shear strength and compressibility than soils along rock sides. These boulder dams stop descending debris, steadily deflecting them toward rock sides, whereas protected soils downslope of blocks are infrequently disturbed and develop into downslope elongated, clast-free fine-earth flags. Kūpaoa were uniformly dispersed across slopes, showing a single-phase mosaic arrangement, without apparent aggregation. Slopes where kūpaoa grows had a relatively uniform distribution of surface sediments; observed kūpaoa patterns may have resulted from the array of microsites generated by surface rocks and sediments, as shrubs simply responded to such spatial structure.

Shear zones of the Verkhoyansk fold-and-thrust belt, Northeast Russia

NASA Astrophysics Data System (ADS)

Fridovsky, Valery; Polufuntikova, Lena

2017-04-01

The Verkhoyansk fold-and-thrust belt is situated on the submerged eastern margin of the North Asian craton, and is largely composed of the Ediacaran - Middle Paleozoic carbonate and the Upper Paleozoic-Mesozoic terrigenous rocks. The Upper Carboniferous - Jurassic sediments constitute the Verkhoyansk terrigenous complex containing economically viable orogenic gold deposits. The structure of the belt is mainly controlled by thrusts and associated diagonal strike slips. Linear concentric folds are common all over the area of the belt. Shear zones with associated similar folds are confined to long narrow areas. Shear zones were formed during the early stages of the Oxfordian-Kimmeridgian collisional and accretionary events prior to the emplacement of large orogenic granitoid plutons. The main ore-controlling structures are shear zones associated with slaty cleavage, shear folds, mullion- and boudinage-structures, and transposition features. The shear zones are listric-type, and represent branches of a detachment structure, which is assumed to be present at the base of the Verkhoyansk fold-and-thrust belt. A vertical zonation of shear zones is correlated with the distance to the detachment. Changes in the dip angle of the shear zones (as indicated mainly by cleavage), structural paragenesis, the degree of microdeformation of the host rocks, and the type of ore-controlling structures can be clearly observed in the direction away from the detachment. Structural zoning is evidenced, among other things, by changing morphologic types of microstructures and by strain-indicators of the degree of rock metamorphism. Four morphologic types of microstructures are identified. The first platy-shear type is characterized by aggregate cleavage and the coefficient of deformation (Cd) of single grains from 1.0 to 2.0. Irregular angular fragments of variously oriented grains can be observed in thin sections. The second shear-cataclastic morphologic type (Cd from 2.0 to 3.0) exhibits combined aggregate and intergranular cleavage. The third cataclastic-segregation morphologic type (Cd from 3.0 to 4.5) is distinguished by a wide distribution of lentelliptical grains of rock-forming minerals in a finely-crystalline matrix and by intergranular cleavage. The rocks of the fourth segregation-striate morphologic type (Cd >5.0) contain lenticular segregations of quartz and feldspar in an intensely linearized mylonite groundmass.

An mDia2/ROCK Signaling Axis Regulates Invasive Egress from Epithelial Ovarian Cancer Spheroids

PubMed Central

Pettee, Krista M.; Dvorak, Kaitlyn M.; Nestor-Kalinoski, Andrea L.; Eisenmann, Kathryn M.

2014-01-01

Multi-cellular spheroids are enriched in ascites of epithelial ovarian cancer (OvCa) patients. They represent an invasive and chemoresistant cellular population fundamental to metastatic dissemination. The molecular mechanisms triggering single cell invasive egress from spheroids remain enigmatic. mDia formins are Rho GTPase effectors that are key regulators of F-actin cytoskeletal dynamics. We hypothesized that mDia2-driven F-actin dynamics promote single cell invasive transitions in clinically relevant three-dimensional (3D) OvCa spheroids. The current study is a dissection of the contribution of the F-actin assembly factor mDia2 formin in invasive transitions and using a clinically relevant ovarian cancer spheroid model. We show that RhoA-directed mDia2 activity is required for tight spheroid organization, and enrichment of mDia2 in the invasive cellular protrusions of collagen-embedded OVCA429 spheroids. Depleting mDia2 in ES-2 spheroids enhanced invasive dissemination of single amoeboid-shaped cells. This contrasts with spheroids treated with control siRNA, where a mesenchymal invasion program predominated. Inhibition of another RhoA effector, ROCK, had no impact on ES-2 spheroid formation but dramatically inhibited spheroid invasion through induction of a highly elongated morphology. Concurrent inhibition of ROCK and mDia2 blocked single cell invasion from ES-2 spheroids more effectively than inhibition of either protein alone, indicating that invasive egress of amoeboid cells from mDia2-depleted spheroids is ROCK-dependent. Our findings indicate that multiple GTPase effectors must be suppressed in order to fully block invasive egress from ovarian cancer spheroids. Furthermore, tightly regulated interplay between ROCK and mDia2 signaling pathways dictates the invasive capacities and the type of invasion program utilized by motile spheroid-derived ovarian cancer cells. As loss of the gene encoding mDia2, DRF3, has been linked to cancer progression and metastasis, our results set the stage for understanding molecular mechanisms involved in mDia2-dependent egress of invasive cells from primary epithelial tumors. PMID:24587343

An mDia2/ROCK signaling axis regulates invasive egress from epithelial ovarian cancer spheroids.

PubMed

Pettee, Krista M; Dvorak, Kaitlyn M; Nestor-Kalinoski, Andrea L; Eisenmann, Kathryn M

2014-01-01

Multi-cellular spheroids are enriched in ascites of epithelial ovarian cancer (OvCa) patients. They represent an invasive and chemoresistant cellular population fundamental to metastatic dissemination. The molecular mechanisms triggering single cell invasive egress from spheroids remain enigmatic. mDia formins are Rho GTPase effectors that are key regulators of F-actin cytoskeletal dynamics. We hypothesized that mDia2-driven F-actin dynamics promote single cell invasive transitions in clinically relevant three-dimensional (3D) OvCa spheroids. The current study is a dissection of the contribution of the F-actin assembly factor mDia2 formin in invasive transitions and using a clinically relevant ovarian cancer spheroid model. We show that RhoA-directed mDia2 activity is required for tight spheroid organization, and enrichment of mDia2 in the invasive cellular protrusions of collagen-embedded OVCA429 spheroids. Depleting mDia2 in ES-2 spheroids enhanced invasive dissemination of single amoeboid-shaped cells. This contrasts with spheroids treated with control siRNA, where a mesenchymal invasion program predominated. Inhibition of another RhoA effector, ROCK, had no impact on ES-2 spheroid formation but dramatically inhibited spheroid invasion through induction of a highly elongated morphology. Concurrent inhibition of ROCK and mDia2 blocked single cell invasion from ES-2 spheroids more effectively than inhibition of either protein alone, indicating that invasive egress of amoeboid cells from mDia2-depleted spheroids is ROCK-dependent. Our findings indicate that multiple GTPase effectors must be suppressed in order to fully block invasive egress from ovarian cancer spheroids. Furthermore, tightly regulated interplay between ROCK and mDia2 signaling pathways dictates the invasive capacities and the type of invasion program utilized by motile spheroid-derived ovarian cancer cells. As loss of the gene encoding mDia2, DRF3, has been linked to cancer progression and metastasis, our results set the stage for understanding molecular mechanisms involved in mDia2-dependent egress of invasive cells from primary epithelial tumors.

Rock and Soil Types at Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

1997-01-01

Type areas of rocks and soils. (A) Dark rock type and bright soil type: Shown is the dark rock Barnacle Bill. Reflectance spectra typical of fresh basalt and APXS spectra indicating more silica-rich basaltic andesite compositions characterize this type. These rocks are typically the small boulders and intermediate-sized cobbles at the Pathfinder site. The bright soil type is very common and in this case comprises Barnacle Bill's wind tail and much of the surround soil area. This soil has a high reflectance and a strongly reddened spectrum indicative of oxidized ferric minerals. (B) Bright rock type: Shown is the bright rock Wedge. Reflectance spectra typical of weathered basalt and APXS spectra indicating basaltic compositions characterize this type. These rocks are typically larger than 1 meter in diameter and many display morphologies indicating flood deposition. (C) Pink rock type: Shown is the pink rock Scooby Doo. APXS and reflectance spectra indicate a composition and optical characteristics similar to the drift soil. However, the morphology of the pink rock type indicates a cemented or rocklike structure. This material may be a chemically cemented hardpan that underlies much of the Pathfinder site. (D) Dark soil type: The dark soil type is typically found on the windward sides of rocks or in rock-free areas like Photometry Flats (shown here) where the bright soil has been striped away by aeolian action or in open areas. Other locations include the Mermaid Dune. (E) Disturbed soil type: The darkening of disturbed soil relative to its parent material, bright soil, as a result of changes in soil texture and compaction caused by movement of the rover and retraction of the lander airbag. (F) Lamb-like soil type: This soil type shows reflectance and spectral characteristics intermediate between the bright and dark soils. Its distinguishing feature is a weak spectral absorption near 900 nanometers not seen in either the bright or dark soils.

NOTE: original caption as published in Science Magazine

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

The Mapping X-ray Fluorescence Spectrometer (MapX)

NASA Astrophysics Data System (ADS)

Sarrazin, P.; Blake, D. F.; Marchis, F.; Bristow, T.; Thompson, K.

2017-12-01

Many planetary surface processes leave traces of their actions as features in the size range 10s to 100s of microns. The Mapping X-ray Fluorescence Spectrometer (MapX) will provide elemental imaging at 100 micron spatial resolution, yielding elemental chemistry at a scale where many relict physical, chemical, or biological features can be imaged and interpreted in ancient rocks on planetary bodies and planetesimals. MapX is an arm-based instrument positioned on a rock or regolith with touch sensors. During an analysis, an X-ray source (tube or radioisotope) bombards the sample with X-rays or alpha-particles / gamma-rays, resulting in sample X-ray Fluorescence (XRF). X-rays emitted in the direction of an X-ray sensitive CCD imager pass through a 1:1 focusing lens (X-ray micro-pore Optic (MPO)) that projects a spatially resolved image of the X-rays onto the CCD. The CCD is operated in single photon counting mode so that the energies and positions of individual X-ray photons are recorded. In a single analysis, several thousand frames are both stored and processed in real-time. Higher level data products include single-element maps with a lateral spatial resolution of 100 microns and quantitative XRF spectra from ground- or instrument- selected Regions of Interest (ROI). XRF spectra from ROI are compared with known rock and mineral compositions to extrapolate the data to rock types and putative mineralogies. When applied to airless bodies and implemented with an appropriate radioisotope source for alpha-particle excitation, MapX will be able to analyze biogenic elements C, N, O, P, S, in addition to the cations of the rock-forming elements >Na, accessible with either X-ray or gamma-ray excitation. The MapX concept has been demonstrated with a series of lab-based prototypes and is currently under refinement and TRL maturation.

A rocking chair type all-solid-state lithium ion battery adopting Li2O-ZrO2 coated LiNi0.8Co0.15Al0.05O2 and a sulfide based electrolyte

NASA Astrophysics Data System (ADS)

Ito, Seitaro; Fujiki, Satoshi; Yamada, Takanobu; Aihara, Yuichi; Park, Youngsin; Kim, Tae Young; Baek, Seung-Wook; Lee, Jae-Myung; Doo, Seokgwang; Machida, Nobuya

2014-02-01

An all-solid-state lithium-ion battery (ASSB) using non-flammable solid electrolytes is a candidate for a next-generation battery. Although the excellent cycle performance and its high energy density are suggested in the literature, a practical size battery has not been appeared yet. In this paper, we have adopted a sulfide based electrolyte, Li2S-P2S5 (80:20 mol%) to a rocking chair type lithium ion battery. The electrochemical cell consists of a Li2O-ZrO2 coated LiNi0.8Co0.15Al0.05O2 (NCA) cathode, an artificial graphite anode and the sulfide based electrolyte without any organic and inorganic liquids. The cathode charge transfer resistance is significantly reduced by the Li2O-ZrO2 coating. The total cell resistance of the Li2O-ZrO2 (LZO) coated NCA adopted cell is approximately one quarter of non-treated one. A standard type single cell with the nominal capacity of 100 mAh at 25 °C is fabricated by wet printing process, and its capacity retention is approximately 80% at 100 cycles. Also, a 1 Ah class battery was constructed by stacking the single cells, and demonstrated.

Musical Preferences are Linked to Cognitive Styles.

PubMed

Greenberg, David M; Baron-Cohen, Simon; Stillwell, David J; Kosinski, Michal; Rentfrow, Peter J

2015-01-01

Why do we like the music we do? Research has shown that musical preferences and personality are linked, yet little is known about other influences on preferences such as cognitive styles. To address this gap, we investigated how individual differences in musical preferences are explained by the empathizing-systemizing (E-S) theory. Study 1 examined the links between empathy and musical preferences across four samples. By reporting their preferential reactions to musical stimuli, samples 1 and 2 (Ns = 2,178 and 891) indicated their preferences for music from 26 different genres, and samples 3 and 4 (Ns = 747 and 320) indicated their preferences for music from only a single genre (rock or jazz). Results across samples showed that empathy levels are linked to preferences even within genres and account for significant proportions of variance in preferences over and above personality traits for various music-preference dimensions. Study 2 (N = 353) replicated and extended these findings by investigating how musical preferences are differentiated by E-S cognitive styles (i.e., 'brain types'). Those who are type E (bias towards empathizing) preferred music on the Mellow dimension (R&B/soul, adult contemporary, soft rock genres) compared to type S (bias towards systemizing) who preferred music on the Intense dimension (punk, heavy metal, and hard rock). Analyses of fine-grained psychological and sonic attributes in the music revealed that type E individuals preferred music that featured low arousal (gentle, warm, and sensual attributes), negative valence (depressing and sad), and emotional depth (poetic, relaxing, and thoughtful), while type S preferred music that featured high arousal (strong, tense, and thrilling), and aspects of positive valence (animated) and cerebral depth (complexity). The application of these findings for clinicians, interventions, and those on the autism spectrum (largely type S or extreme type S) are discussed.

Cryolithozone of Western Arctic shelf of Russia

NASA Astrophysics Data System (ADS)

Kholmyanskii, Mikhail; Vladimirov, Maksim; Snopova, Ekaterina; Kartashev, Aleksandr

2017-04-01

We propose a new original version of the structure of the cryolithozone of west Arctic seas of Russia. In contrast to variants of construction of sections and maps based on thermodynamic modeling, the authors have used electrometric, seismic, and thermal data including their own profile measurements by near-field transient electromagnetic technique and seismic profile observations by reflection method. As a result, we defined the spatial characteristics of cryolithozone and managed to differentiate it to several layers, different both in structure and formation time. We confirmed once again that the spatial boundary of cryolithozone, type and thickness of permafrost, chilled rocks and thawed ground are primarily determined by tectonic and oceanographic regimes of the Arctic Ocean and adjacent land in different geological epochs. Permafrost formed on the land in times of cold weather, turn to submarine during flooding and overlap, in the case of the sea transgression, by marine sediments accumulating in the period of warming. We have been able to establish a clear link between the permafrost thickness and the geomorphological structure of the area. This can be explained by the distribution of thermodynamic flows that change the temperature state of previously formed permafrost rocks. Formation in the outer parts of the shelf which took place at ancient conversion stage can be characterized by the structure: • permafrost table - consists of rocks, where the sea water with a temperature below 0 °C has replaced the melted ice; • middle horizon - composed of undisturbed rocks, and the rocks chilled through the lower sieving underlay; As a result of the interpretation and analysis of all the available data, the authors created a map of types of cryolithozone of the Western Arctic shelf of Russia. The following distribution areas are marked on the map: • single-layer cryolithozone (composed of sediments upper Pleistocene and Holocene); • monosyllabic relict permafrost; • two-layer relict permafrost; • three-layered cryolithozone (composed of Holocene rocks and two-layer relict mainly from permafrost rocks); • three-layer cryolithozone (composed of Holocene rocks and two-layer relict mainly from chilled rocks); • post-cryogenic thawed sediments.

Petrophysical Rock Typing of Unconventional Shale Plays: A Case Study for the Niobrara Formation of the Denver-Julesburg (DJ) Basin

NASA Astrophysics Data System (ADS)

Kamruzzaman, A.; Prasad, M.

2015-12-01

The hydrocarbon-rich mudstone rock layers of the Niobrara Formation were deposited in the shallow marine environment and have evolved as overmature oil- or gas-prone source and reservoir rocks. The hydrocarbon production from its low-porosity, nano-darcy permeability and interbedded chalk-marl reservoir intervals is very challenging. The post-diagenetic processes have altered the mineralogy and pore structure of its sourcing and producing rock units. A rock typing analysis in this play can help understand the reservoir heterogeneity significantly. In this study, a petrophysical rock typing workflow is presented for the Niobrara Formation by integrating experimental rock properties with geologic lithofacies classification, well log data and core study.Various Niobrara lithofacies are classified by evaluating geologic depositional history, sequence stratigraphy, mineralogy, pore structure, organic content, core texture, acoustic properties, and well log data. The experimental rock measurements are conducted on the core samples recovered from a vertical well from the Wattenberg Field of the Denver-Julesburg (DJ) Basin. Selected lithofacies are used to identify distinct petrofacies through the empirical analysis of the experimental data-set. The grouped petrofacies are observed to have unique mineralogical properties, pore characteristics, and organic contents and are labelled as discrete Niobrara rock types in the study area.Micro-textural image analysis (FESEM) is performed to qualitatively examine the pore size distribution, pore types and mineral composition in the matrix to confirm the classified rock units. The principal component analysis and the cluster analysis are carried out to establish the certainty of the selected rock types. Finally, the net-to-pay thicknesses of these rock units are compared with the cumulative production data from the field to further validate the chosen rock types.For unconventional shale plays, the rock typing information can be used to locate hydrocarbon sweetspots, facilitate the placement of the horizontal section of the wells along the sweetspots, and can augment engineers' abilities on suitable well placement considerations. It can also help enhancing the effectiveness of the hydraulic fracture stimulation and completion operation.

Rockbursting Potential of Kimberlite: A Case Study of Diavik Diamond Mine

NASA Astrophysics Data System (ADS)

Leveille, Paul; Sepehri, Mohammadali; Apel, Derek B.

2017-12-01

The research described in this paper provides information about the rockbursting potential of kimberlite. Kimberlite is a diamond-bearing rock found in deposits around the world including northern Canada. This paper outlines three methods for the prediction of rockbursts based on the properties of a rock. The methods include the: strain energy index, strain energy density, and rock brittleness. Kimberlite samples collected from Diavik, a diamond mine in northern Canada, were tested to define the rock's uniaxial compressive strength, tensile strength, and hysteresis loop. The samples were separated into sub-rock types based on their descriptions from the mine geologists. The results indicate that it is possible to produce rockbursts in kimberlite. It was also observed that the sub-rock types had a range of rockbursting properties. Some types of kimberlite exhibited little to no potential for producing bursts, while other types potentially could produce violent bursts. The diverse nature of kimberlite indicates that the rockbursting properties of the rock should not be generalized and are dependent on the sub-rock type being encountered.

Musical Preferences are Linked to Cognitive Styles

PubMed Central

Greenberg, David M.; Baron-Cohen, Simon; Stillwell, David J.; Kosinski, Michal; Rentfrow, Peter J.

2015-01-01

Why do we like the music we do? Research has shown that musical preferences and personality are linked, yet little is known about other influences on preferences such as cognitive styles. To address this gap, we investigated how individual differences in musical preferences are explained by the empathizing-systemizing (E-S) theory. Study 1 examined the links between empathy and musical preferences across four samples. By reporting their preferential reactions to musical stimuli, samples 1 and 2 (Ns = 2,178 and 891) indicated their preferences for music from 26 different genres, and samples 3 and 4 (Ns = 747 and 320) indicated their preferences for music from only a single genre (rock or jazz). Results across samples showed that empathy levels are linked to preferences even within genres and account for significant proportions of variance in preferences over and above personality traits for various music-preference dimensions. Study 2 (N = 353) replicated and extended these findings by investigating how musical preferences are differentiated by E-S cognitive styles (i.e., ‘brain types’). Those who are type E (bias towards empathizing) preferred music on the Mellow dimension (R&B/soul, adult contemporary, soft rock genres) compared to type S (bias towards systemizing) who preferred music on the Intense dimension (punk, heavy metal, and hard rock). Analyses of fine-grained psychological and sonic attributes in the music revealed that type E individuals preferred music that featured low arousal (gentle, warm, and sensual attributes), negative valence (depressing and sad), and emotional depth (poetic, relaxing, and thoughtful), while type S preferred music that featured high arousal (strong, tense, and thrilling), and aspects of positive valence (animated) and cerebral depth (complexity). The application of these findings for clinicians, interventions, and those on the autism spectrum (largely type S or extreme type S) are discussed. PMID:26200656

Rock type discrimination techniques using Landsat and Seasat image data

NASA Technical Reports Server (NTRS)

Blom, R.; Abrams, M.; Conrad, C.

1981-01-01

Results of a sedimentary rock type discrimination project using Seasat radar and Landsat multispectral image data of the San Rafael Swell, in eastern Utah, are presented, which has the goal of determining the potential contribution of radar image data to Landsat image data for rock type discrimination, particularly when the images are coregistered. The procedure employs several images processing techniques using the Landsat and Seasat data independently, and then both data sets are coregistered. The images are evaluated according to the ease with which contacts can be located and rock units (not just stratigraphically adjacent ones) separated. Results show that of the Landsat images evaluated, the image using a supervised classification scheme is the best for sedimentary rock type discrimination. Of less value, in decreasing order, are color ratio composites, principal components, and the standard color composite. In addition, for rock type discrimination, the black and white Seasat image is less useful than any of the Landsat color images by itself. However, it is found that the incorporation of the surface textural measures made from the Seasat image provides a considerable and worthwhile improvement in rock type discrimination.

Oreshoot zoning in the Carlin-type Betze orebody, Goldstrike Mine, Eureka County, Nevada

USGS Publications Warehouse

Peters, Stephen G.; Ferdock, Gregory C.; Woitsekhowskaya, Maria B.; Leonardson, Robert; Rahn, Jerry

1998-01-01

Field and laboratory investigations of the giant Betze gold orebody, the largest Carlin-type deposit known, in the north-central Carlin trend, Nevada document that the orebody is composed of individual high-grade oreshoots that contain different geologic, mineralogic, and textural characteristics. The orebody is typical of many structurally controlled Carlin-type deposits, and is hosted in thin-bedded, impure carbonate or limy siltstone, breccia bodies, and intrusive or calc-silicate rock. Most ores in the Betze orebody are highly sheared or brecciated and show evidence of syndeformational hydrothermal deposition. The interplay between rock types and pre- and syn-structural events accounts for most of the distribution and zoning of the oreshoots. Hydrothermal alteration is scale dependent, either in broad, pervasive alteration patterns, or in areas related to various oreshoots. Alteration includes decarbonatization (~decalcification) of carbonate units, argillization (illite-clay), and silicification. Patterns of alteration zoning in and surrounding the Betze orebody define a large porous, dilated volume of rock where high fluid flow predominated. Local restriction of alteration to narrow illite- and clay-rich selvages around unaltered marble or calc-silicate rock phacoids implies that fluid flow favored permeable structures and deformed zones. Gold mainly is present as disseminated sub-micron-sized particles, commonly associated with Asñrich pyrite, although one type of oreshoot contains micron-size free gold. Oreshoots form a three-dimensional zoning pattern in the orebody within a WNW-striking structural zone of shearing and shear folding, termed the Dillon deformation zone (DDZ). Main types of oreshoots are: (1) rutile-bearing siliceous oreshoots; (2) illite-clay-pyrite oreshoots; (3) realgar- and orpiment-bearing oreshoots; (4) stibnite-bearing siliceous oreshoots; and (5) polymetallic oreshoots. Zoning patterns result from paragenetically early development of illite-clay-pyrite oreshoots during movement along the DDZ, and subsequent silicification and brecciation, associated with formation of the realgar- and orpiment-bearing, and stibnite-bearing oreshoots. Additional shear movement along the DDZ followed. Polymetallic oreshoots, which contain minerals rich in Hg, Cu, Zn, Ag, and native Au, were the last ores to form and overprint most earlier oreshoots. Ore textures, gouge, phyllonitic rock, alteration style, and previously documented isotopic and fluid-inclusion data, all indicate a weakly to moderately saline fluid that ascended and cooled during structural displacements. Changing conditions, due to water-wall rock reactions and P-T changes during deformation, are probably responsible for fluid variation that resulted in zoning of the different oreshoots during dynamic interaction of the Au-bearing fluid with the wall rock. This investigation indicates that isolated As-, Sb-, and Hg-rich ores are separate parts of a larger single gold system. This large gold system was contemporaneous with post-Jurassic brittle-ductile deformation, on the basis of deformed mineralized pods of the Jurassic Goldstrike pluton, and large-scale hydrothermal flow, and together they appear to be an integral part of the formation of some Carlin-type gold deposits in north-central Nevada.

An evaluation of thematic mapper simulator data for the geobotanical discrimination of rock types in Southwest Oregon

NASA Technical Reports Server (NTRS)

Weinstock, K. J.; Morrissey, L. A.

1984-01-01

Rock type identification may be assisted by the use of remote sensing of associated vegetation, particularly in areas of dense vegetative cover where surface materials are not imaged directly by the sensor. The geobotanical discrimination of ultramafic parent materials was investigated and analytical techniques for lithologic mapping and mineral exploration were developed. The utility of remotely sensed data to discriminate vegetation types associated with ultramafic parent materials in a study area in southwest Oregon were evaluated. A number of specific objectives were identified, which include: (1) establishment of the association between vegetation and rock types; (2) examination of the spectral separability of vegetation types associated with rock types; (3) determination of the contribution of each TMS band for discriminating vegetation associated with rock types and (4) comparison of analytical techniques for spectrally classifying vegetation.

Petrology of unshocked crystalline rocks and shock effects in lunar rocks and minerals

USGS Publications Warehouse

Chao, E.C.T.; James, O.B.; Minkin, J.A.; Boreman, J.A.; Jackson, E.D.; Raleigh, C.B.

1970-01-01

On the basis of rock modes, textures, and mineralogy, unshocked crystalline rocks are classified into a dominant ilmenite-rich suite (subdivided into intersertal, ophitic, and hornfels types) and a subordinate feldspar-rich suite (subdivided into poikilitic and granular types). Weakly to moderately shocked rocks show high strain-rate deformation and solid-state transformation of minerals to glasses; intensely shocked rocks are converted to rock glasses. Data on an unknown calcium-bearing iron metasilicate are presented.

ROCK2 and MYLK variants under hypobaric hypoxic environment of high altitude associate with high altitude pulmonary edema and adaptation

PubMed Central

Pandey, Priyanka; Mohammad, Ghulam; Singh, Yogendra; Qadar Pasha, MA

2015-01-01

Objective To date, a major class of kinases, serine–threonine kinase, has been scantly investigated in stress-induced rare, fatal (if not treated early), and morbid disorder, high altitude pulmonary edema (HAPE). This study examined three major serine–threonine kinases, ROCK2, MYLK, and JNK1, along with six other genes, tyrosine hydroxylase, G-protein subunits GNA11 and GNB3, and alpha1 adrenergic receptor isoforms 1A, 1B, and 1D as candidate gene markers of HAPE and adaptation. Methods For this, 57 variants across these nine genes were genotyped in HAPE patients (n=225), HAPE controls (n=210), and highlanders (n=259) by Sequenom MS (TOF)-based MassARRAY® platform using iPLEX™ Gold technology. In addition, to study the gene expression, quantitative real-time polymerase chain reaction was performed in human peripheral blood mononuclear cells of the three study groups. Results A significant association was observed for C allele (ROCK2 single-nucleotide polymorphism, rs10929728) with HAPE (P=0.03) and C, T, and A alleles (MYLK single-nucleotide polymorphisms, rs11717814, rs40305, and rs820336) with both HAPE and adaptation (P=0.001, P=0.006, and P=0.02, respectively). ROCK2 88 kb GGGTTGGT haplotype was associated with lower risk of HAPE (P=0.0009). MYLK 7 kb haplotype CTA, composed of variant alleles, was associated with higher risk of HAPE (P=0.0006) and lower association with adaptation (P=1E–06), whereas haplotype GCG, composed of wild-type alleles, was associated with lower risk of HAPE (P=0.001) and higher association with adaptation (P=1E–06). Haplotype–haplotype and gene–gene interactions demonstrated a correlation in working of ROCK2 and MYLK. Conclusion The data suggest the association of ROCK2 with HAPE and MYLK with HAPE and adaptation in Indian population. The outcome has provided new insights into the physiology of HAPE and adaptation. PMID:26586960

Foliation boudinage

NASA Astrophysics Data System (ADS)

Arslan, Arzu; Passchier, Cees W.; Koehn, Daniel

2008-03-01

Foliation boudinage is a form of boudinage that develops in foliated rocks independent of lithology contrast. This paper describes foliation boudins from the Çine Massif in SW Turkey and the Furka Pass-Urseren Zone in central Switzerland. Four common types of foliation boudin structures can be distinguished in the field, named after vein geometries in their boudin necks in sections normal to the boudin axis: lozenge-, crescent-, X- and double crescent-type. The boudin necks are mostly filled with massive quartz in large single crystals, commonly associated with tourmaline, feldspar and biotite and in some cases with chlorite spherulites. The presence of blocky crystals and chlorite spherulites suggests that these veins formed as open, fluid-filled cavities during the initiation and development of foliation boudin structures, even in ductilely deforming gneiss at a depth of mid-crustal levels (7-10 kbar). The presence of cavities allowed the formation of closed fishmouth structures that are typical for many foliation boudins. The geometry of foliation boudin structures mainly depends on initial fracture orientation, propagation of the fracture during further deformation, and flow type in the wall rock.

Shear heating and metamorphism in subduction zones, 2. The seismic-aseismic transition at c. 50 km depth.

NASA Astrophysics Data System (ADS)

Castro, A. E.; Spear, F. S.; Kohn, M. J.

2017-12-01

Recent work demonstrates that shear heating, which is required for explaining fore-arc heat flow, reconciles thermal models with pressure-temperature (P-T) conditions determined from exhumed metamorphic rocks, i.e. exhumed rocks are representative of normal subduction. However, the range of subduction conditions on Earth (age, angle and rate of subducting plate, character of overriding plate, coefficient of friction, etc.) implies a ≥250 °C range of corresponding temperatures at the depth of the seismic-aseismic transition (SAT), which is consistently observed at 40-60 km in subduction zones worldwide. Here we show that the predicted rheologies and mineral stabilities for 3 common rock types fail to explain the global consistency of the SAT depth, and we propose that mechanical removal of the weakest rocks is required. Using either realistic thermal models, or P-T conditions recorded by exhumed metamorphic rocks, a substantial subset of depths corresponding with any single petrologic or rheological process falls outside the relatively restricted 40-60 km depth of the SAT. For example, a thermal weakening mechanism (the brittle-ductile transition) implies a wide range of depths, regardless of proposed T (e.g. 20-30 km (300 °C), 25-60 km (400 °C), 35 to >85 km (500 °C), etc). Similarly, individual dehydration reactions span a larger range of depths than observed for the SAT; for example, chlorite-out (metapelites: 35 to >85 km; metabasalts: 40 to >85 km), brucite-out (35-75 km) and serpentine/talc-out (50 to >80 km). The failure of a single petrologic and rheological trigger for these characteristic rocks to produce a consistent SAT depth implies that these rocks do not control the SAT, and consequently must not be abundant at depths below the SAT. That is, these hydrated, weak, and buoyant rocks must be squeezed out of the subduction system, although subduction of discontinuous blobs or lenses to greater depth, e.g. to feed arc volcanoes, may occur. The SAT instead may represent progressive strengthening of the subduction interface through mechanical exclusion of weak rocks and formation of stiffer minerals with increasing temperature and depth. Ultimately, as the strengths of the slab and mantle wedge converge at c. 80 km depth, mechanical coupling occurs, driving mantle wedge convection.

A Lithology Based Map Unit Schema For Onegeology Regional Geologic Map Integration

NASA Astrophysics Data System (ADS)

Moosdorf, N.; Richard, S. M.

2012-12-01

A system of lithogenetic categories for a global lithological map (GLiM, http://www.ifbm.zmaw.de/index.php?id=6460&L=3) has been compiled based on analysis of lithology/genesis categories for regional geologic maps for the entire globe. The scheme is presented for discussion and comment. Analysis of units on a variety of regional geologic maps indicates that units are defined based on assemblages of rock types, as well as their genetic type. In this compilation of continental geology, outcropping surface materials are dominantly sediment/sedimentary rock; major subdivisions of the sedimentary category include clastic sediment, carbonate sedimentary rocks, clastic sedimentary rocks, mixed carbonate and clastic sedimentary rock, colluvium and residuum. Significant areas of mixed igneous and metamorphic rock are also present. A system of global categories to characterize the lithology of regional geologic units is important for Earth System models of matter fluxes to soils, ecosystems, rivers and oceans, and for regional analysis of Earth surface processes at global scale. Because different applications of the classification scheme will focus on different lithologic constituents in mixed units, an ontology-type representation of the scheme that assigns properties to the units in an analyzable manner will be pursued. The OneGeology project is promoting deployment of geologic map services at million scale for all nations. Although initial efforts are commonly simple scanned map WMS services, the intention is to move towards data-based map services that categorize map units with standard vocabularies to allow use of a common map legend for better visual integration of the maps (e.g. see OneGeology Europe, http://onegeology-europe.brgm.fr/ geoportal/ viewer.jsp). Current categorization of regional units with a single lithology from the CGI SimpleLithology (http://resource.geosciml.org/201202/ Vocab2012html/ SimpleLithology201012.html) vocabulary poorly captures the lithologic character of such units in a meaningful way. A lithogenetic unit category scheme accessible as a GeoSciML-portrayal-based OGC Styled Layer Description resource is key to enabling OneGeology (http://oneGeology.org) geologic map services to achieve a high degree of visual harmonization.

Shock metamorphism of planetary silicate rocks and sediments: Proposal for an updated classification system

NASA Astrophysics Data System (ADS)

Stöffler, Dieter; Hamann, Christopher; Metzler, Knut

2018-01-01

We reevaluate the systematics and geologic setting of terrestrial, lunar, Martian, and asteroidal "impactites" resulting from single or multiple impacts. For impactites derived from silicate rocks and sediments, we propose a unified and updated system of progressive shock metamorphism. "Shock-metamorphosed rocks" occur as lithic clasts or melt particles in proximal impactites at impact craters, and rarely in distal impactites. They represent a wide range of metamorphism, typically ranging from unshocked to shock melted. As the degree of shock metamorphism, at a given shock pressure, depends primarily on the mineralogical composition and the porosity of a rock or sediment sample, different shock classification systems are required for different types of planetary rocks and sediments. We define shock classification systems for eight rock and sediment classes which are assigned to three major groups of rocks and sediments (1) crystalline rocks with classes F, M, A, and U; (2) chondritic rocks (class C); and (3) sedimentary rocks and sediments with classes SR, SE, and RE. The abbreviations stand for felsic (F), mafic (M), anorthositic (A), ultramafic (U), sedimentary rocks (SR), unconsolidated sediments (SE), and regoliths (RE). In each class, the progressive stages of shock metamorphism are denominated S1 to Sx. These progressive shock stages are introduced as: S1-S7 for F, S1-S7 for M, S1-S6 for A, S1-S7 for U, S1-S7 for C, S1-S7 for SR, S1-S5 for SE, and S1-S6 for RE. S1 stands for "unshocked" and Sx (variable between S5 and S7) stands for "whole rock melting." We propose a sequence of symbols characterizing the degree of shock metamorphism of a sample, i.e., F-S1 to F-S7 with the option to add the tabulated pressure ranges (in GPa) in parentheses.

Whole-rock and mineral compositional constraints on the magmatic evolution of the Ni-Cu-(PGE) sulfide ore-bearing Kevitsa intrusion, northern Finland

NASA Astrophysics Data System (ADS)

Luolavirta, Kirsi; Hanski, Eero; Maier, Wolfgang; Santaguida, Frank

2018-01-01

The 2.06 Ga mafic-ultramafic Kevitsa intrusion is located in the Central Lapland greenstone belt. The lower ultramafic part of the intrusion hosts a large disseminated Ni-Cu-(PGE) sulfide deposit with Ni tenors ranging widely from < 4 wt% (uneconomic false ore and contact mineralization) to 4-7 wt% (regular ore) and up to 40 wt% (Ni-PGE ore). The stratigraphy of the ultramafic cumulates is divided into the basal pyroxenite-gabbro (Basal series), olivine pyroxenite (OLPX), pyroxenite, and plagioclase-bearing (ol) websterite (pOLWB), of which the latter occurs together with minor microgabbros in the ore-bearing domain of the intrusion. Around the ore domain, the ultramafic cumulate succession records a simple lithological stratigraphy and modest and predictable variations in whole-rock and mineral compositions. The ore-bearing domain, in contrast, is characterized by a complex internal architecture, variations in whole-rock and mineral compositions, and the presence of numerous inclusions and xenoliths. The OLPXs are mainly composed of cumulus olivine (Fo77-89) and clinopyroxene (Mg#81-92) with variable amounts of oikocrystic orthopyroxene (Mg#79-84). They comprise the bulk of the ultramafic cumulates and are the dominant host rocks to the sulfide ore. The host rocks to the regular and false ore type are mineralogically and compositionally similar (Fo 80-83, mostly) and show mildly LREE-enriched REE patterns (CeN/YbN 2), characteristic for the bulk of the Kevitsa ultramafic cumulates. The abundance of orthopyroxene and magnetite is lowest in the host rocks to the Ni-PGE ore type, being in line with the mineral compositions of the silicates, which are the most primitive in the intrusion. However, it contrasts with the LREE-enriched nature of the ore type (CeN/YbN 7), indicating significant involvement of crustal material in the magma. The contrasting intrusive stratigraphy in the different parts of the intrusion likely reflects different emplacement histories. It is proposed that the Kevitsa magma chamber was initially filled by stable continuous flow ("single" input) of basaltic magma followed by differentiation in an at least nearly closed system. In the following stage, new magma pulses were repeatedly emplaced into the interior of the intrusion in a dynamic (open) system forming the sulfide ore bodies. To gain the peculiar compositional and mineralogical characteristics of the Ni-PGE ore type, the related magma probably interacted with different country rocks en route to the Kevitsa magma chamber.

77 FR 23665 - Procurement List Proposed Additions

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-20

...: Services Service Type/Location: Mailroom Operations, Official Mail Distribution Center, 1 Rock Island Arsenal, Building 132, Rock Island, IL. NPA: The Arc of the Quad Cities Area, Rock Island, IL. Contracting Activity: Dept of the ARMY, W4MM USA Joint Munitions CMD, Rock Island, IL. Service Type/Location: Custodial...

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.

Geology and Geochemistry of Magmatic Rocks from the Southern Part of the Kyushu-Palau Ridge in the Philippine Sea

NASA Astrophysics Data System (ADS)

Lelikov, E. P.; Sedin, V. T.; Pugachev, A. A.

2018-03-01

The paper reports the results of a geochemical study of volcanogenic rocks from the southern part of the Kyushu-Palau Ridge. Volcanic structures, such as plateaulike rises, mountain massifs, and single volcanoes, are the major relief-forming elements of the southern part of the Kyushu-Palau Ridge. They are divided into three types according to the features of the relief and geological structure: shield, cone-shaped, and dome-shaped volcanoes. The ridge was formed on oceanic crust in the Late Mesozoic and underwent several stages of evolution with different significance and application of forces (tension and compression). Change in the geodynamic conditions during the geological evolution of the ridge mostly determined the composition of volcanic rocks of deep-mantle nature. Most of the ridge was formed by the Early Paleogene under geodynamic conditions close to the formation of oceanic islands (shield volcanoes) under tension. The island arc formed on the oceanic basement in the compression mode in the Late Eocene-Early Oligocene. Dome-shaped volcanic edifices composed of alkaline volcanic rocks were formed in the Late Oligocene-Early Miocene under tension. Based on the new geochemical data, detailed characteristics of volcanic rocks making up the shield, cone-shape, and dome-shape stratovolcanoes resulting in the features of these volcanic edifices are given for the first time. Continuous volcanism (with an age from the Cretaceous to the Late Miocene and composition from oceanic tholeiite to calc-alkaline volcanites of the island arc type) resulting in growth of the Earth's crust beneath the Kyushu-Palau Ridge was the major factor in the formation this ridge.

Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

NASA Astrophysics Data System (ADS)

Hammond, Patrick A.

2018-02-01

Most studies of fractured-rock aquifers are about analytical models used for evaluating aquifer tests or numerical methods for describing groundwater flow, but there have been few investigations on how to estimate the reliable long-term drought yields of individual hard-rock wells. During the drought period of 1998 to 2002, many municipal water suppliers in the Piedmont/Blue Ridge areas of central Maryland (USA) had to institute water restrictions due to declining well yields. Previous estimates of the yields of those wells were commonly based on extrapolating drawdowns, measured during short-term single-well hydraulic pumping tests, to the first primary water-bearing fracture in a well. The extrapolations were often made from pseudo-equilibrium phases, frequently resulting in substantially over-estimated well yields. The methods developed in the present study to predict yields consist of extrapolating drawdown data from infinite acting radial flow periods or by fitting type curves of other conceptual models to the data, using diagnostic plots, inverse analysis and derivative analysis. Available drawdowns were determined by the positions of transition zones in crystalline rocks or thin-bedded consolidated sandstone/limestone layers (reservoir rocks). Aquifer dewatering effects were detected by type-curve matching of step-test data or by breaks in the drawdown curves constructed from hydraulic tests. Operational data were then used to confirm the predicted yields and compared to regional groundwater levels to determine seasonal variations in well yields. Such well yield estimates are needed by hydrogeologists and water engineers for the engineering design of water systems, but should be verified by the collection of long-term monitoring data.

Benchmark Design and Installation: A synthesis of Existing Information.

DTIC Science & Technology

1987-07-01

casings (15 ft deep) drilled to rock and filled with concrete. Disks - 1 . Set on vertically stable structures (e.g., dam monoliths). 2 . Set in rock ...Structural movement survey 1 . Rock outcrops (first choice) -- chiseled square on high point. 2 . Massive concrete structure (second choice) - cut square on...bolt marker (type 2 ). 58,. % %--"% %I 1 ± 4 -I,.- Table Cl. Recomnded benchmarks. Type of condition or terrain Type of markert Bedrock, rock outcrops

Magnetic anisotropy behaviour of pyrrhotite as determined by low- and high-field experiments

NASA Astrophysics Data System (ADS)

Martín-Hernández, F.; Dekkers, M. J.; Bominaar-Silkens, I. M. A.; Maan, J. C.

2008-07-01

Here we report on the sources of magnetic anisotropy in pyrrhotite, an iron sulphide present in many rocks as an important carrier of the Natural Remanent Magnetization. While the magnetic hysteresis parameters of pyrrhotite are well known, the existing database concerning its anisotropy behaviour is patchy and ambiguous. Therefore, a collection of 11 seemingly single crystals of natural pyrrhotite was scrutinized. Before embarking on the anisotropy determinations the set of single crystals was extensively characterized rock magnetically by measuring Curie temperatures, hysteresis loops, IRM acquisition curves, and FORC diagrams (the latter three all at room temperature). First the variation of the low-field susceptibility as function of applied field and grain size was evaluated for fields ranging from 1 to 450 A m-1. Existing grain size dependent data and the present larger crystals show a logarithmic grain size dependence. This enables estimating the grain size for unimodal pyrrhotite distributions in rocks. Measured trends are better fitted with an exponential function than with a Rayleigh Law style function. Based on the rock magnetic characterization and the behaviour of the anisotropy of magnetic susceptibility six samples (of the original 11) were selected for the high-field anisotropy determinations within the basal plane. Those data were acquired with a torque cantilever-type magnetometer. As expected, most single crystals showed a pure 6-θ curve within their basal plane because of the easy axis configuration. In some crystals, however, lower harmonic terms overlapped the 6-θ term. This may be the dominant source of the observed variation in magnetic anisotropy properties. Torque data of three of the six samples were of sufficient quality to allow evaluation of K1. Re-evaluation of existing torque data and including the present newly derived determinations, yields for the anisotropy constant of pyrrhotite within the basal plane K1: (2.7 +/- 0.2) 104 Jm-3. This is over an order of magnitude more precise than the sparse existing K1 data; only the value reported by Mikami and co-authors in 1959 agrees with the new determination. With this firmly established K1 value meaningful anisotropy models are now possible for pyrrhotite-bearing rocks.

Joint simulation of stationary grade and non-stationary rock type for quantifying geological uncertainty in a copper deposit

NASA Astrophysics Data System (ADS)

Maleki, Mohammad; Emery, Xavier

2017-12-01

In mineral resources evaluation, the joint simulation of a quantitative variable, such as a metal grade, and a categorical variable, such as a rock type, is challenging when one wants to reproduce spatial trends of the rock type domains, a feature that makes a stationarity assumption questionable. To address this problem, this work presents methodological and practical proposals for jointly simulating a grade and a rock type, when the former is represented by the transform of a stationary Gaussian random field and the latter is obtained by truncating an intrinsic random field of order k with Gaussian generalized increments. The proposals concern both the inference of the model parameters and the construction of realizations conditioned to existing data. The main difficulty is the identification of the spatial correlation structure, for which a semi-automated algorithm is designed, based on a least squares fitting of the data-to-data indicator covariances and grade-indicator cross-covariances. The proposed models and algorithms are applied to jointly simulate the copper grade and the rock type in a Chilean porphyry copper deposit. The results show their ability to reproduce the gradual transitions of the grade when crossing a rock type boundary, as well as the spatial zonation of the rock type.

Chronology of early Archaean granite-greenstone evolution in the Barberton Mountain Land, South Africa, based on precise dating by single zircon evaporation.

PubMed

Krüner, A; Byerly, G R; Lowe, D R

1991-04-01

We report precise 207Pb/206Pb single zircon evaporation ages for low-grade felsic metavolcanic rocks within the Onverwacht and Fig Tree Groups of the Barberton Greenstone Belt (BGB), South Africa, and from granitoid plutons bordering the belt. Dacitic tuffs of the Hooggenoeg Formation in the upper part of the Onverwacht Group yield ages between 3445 +/- 3 and 3416 +/- 5 Ma and contain older crustal components represented by a 3504 +/- 4 Ma old zircon xenocryst. Fig Tree dacitic tuffs and agglomerates have euhedral zircons between 3259 +/- 5 and 3225 +/- 3 Ma in age which we interpret to reflect the time of crystallization. A surprisingly complex xenocryst population in one sample documents ages from 3323 +/- 4 to 3522 +/- 4 Ma. We suspect that these xenocrysts were inherited, during the passage of the felsic melts to the surface, from various sources such as greenstones and granitoid rocks now exposed in the form of tonalite-trondhjemite plutons along the southern and western margins of the BGB, and units predating any of the exposed greenstone or intrusive rocks. Several of the granitoids along the southern margin of the belt have zircon populations with ages between 3490 and 3440 Ma. coeval with or slightly older than Onverwacht felsic volcanism, while the Kaap Valley pluton along the northwestern margin of the belt is coeval with Fig Tree dacitic volcanism. These results emphasize the comagmatic relationships between greenstone felsic volcanic units and the surrounding plutonic suites. Some of the volcanic plutonic units contain zircon xenocrysts older than any exposed rocks. These indicate the existence of still older units, possibly stratigraphically lower and older portions of the greenstone sequence itself, older granitoid intrusive rocks, or bodies of older, unrelated crustal material. Our data show that the Onverwacht and Fig Tree felsic units have distinctly different ages and therefore do not represent a single, tectonically repeated unit as proposed by others. Unlike the late Archaean Abitibi greenstone belt in Canada, which formed over about 30 Ma. exposed rocks in the BGB formed over a period of at least 220 Ma. The complex zircon populations encountered in this study imply that conventional multigrain zircon dating may not accurately identify the time of felsic volcanic activity in ancient greenstones. A surprising similarity in rock types, tectonic evolution, and ages of the BGB in the Kaapvaal craton of southern Africa and greenstones in the Pilbara Block of Western Australia suggests that these two terrains may have been part of a larger crustal unit in early Archaean times.

Apollo 17 KREEPy basalts - Evidence for nonuniformity of KREEP

NASA Technical Reports Server (NTRS)

Salpas, Peter A.; Taylor, Lawrence A.; Lindstrom, Marilyn M.

1987-01-01

Breccia 72275 contains pristine KREEPy basalt clasts that are not found among other samples collected at Apollo 17. These basalts occur as discrete clasts and as clasts enclosed within basaltic microbreccias. Mineral and whole-rock chemical analyses reveal that the microbreccias are compositionally indistinguishable from the basalt clasts. Samples of the 72275 matrix also have the same compositions as the basalts and the basaltic microbreccias. 72275 was assembled in situ from a single flow or series of closely related flows of Apollo 17 KREEPy basalt before it was transported to the Apollo 17 site. As a rock type, Apollo 17 KREEPy basalts are distinct from Apollo 15 KREEP basalts. The Apollo 17 samples have lower REE concentrations, steeper negative slopes of the HREE, and are less magnesian than the Apollo 15 samples. The two basalt types cannot be related by fractional crystallization, partial melting, or assimilation. This is evidence for the compositional nonuniformity of KREEP as a function of geography.

Zealotry promotes coexistence in the rock-paper-scissors model of cyclic dominance

NASA Astrophysics Data System (ADS)

Verma, Gunjan; Chan, Kevin; Swami, Ananthram

2015-11-01

Cyclic dominance models, such as the classic rock-paper-scissors (RPS) game, have found real-world applications in biology, ecology, and sociology. A key quantity of interest in such models is the coexistence time, i.e., the time until at least one population type goes extinct. Much recent research has considered conditions that lengthen coexistence times in an RPS model. A general finding is that coexistence is promoted by localized spatial interactions (low mobility), while extinction is fostered by global interactions (high mobility). That is, there exists a mobility threshold which separates a regime of long coexistence from a regime of rapid collapse of coexistence. The key finding of our paper is that if zealots (i.e., nodes able to defeat others while themselves being immune to defeat) of even a single type exist, then system coexistence time can be significantly prolonged, even in the presence of global interactions. This work thus highlights a crucial determinant of system survival time in cyclic dominance models.

The role of major forest fires on rock physical decay in a Mediterranean environment

NASA Astrophysics Data System (ADS)

Shtober-Zisu, Nurit; Tessler, Naama; Tsatskin, Alexander; Greenbaum, Noam

2017-04-01

Massive destruction of carbonate rocks occurred on the slopes of Mt. Carmel (Israel), during a severe forest fire in 2010. The bedrock surfaces exhibited extensive exfoliation into flakes and spalls covering up to 80%-100% of the exposed rocks; detached boulders were totally fractured or disintegrated. The fire affected six carbonate units—various types of chalk, limestone, and dolomite. The burned flakes show a consistent tendency towards flatness, in all lithologies, as 85%-95% of the flakes were detached in the form of blades, plates, and slabs. The extent of the physical disruption depends on rock composition: the most severe response was found in the chalk formations which are covered by calcrete (Nari crusts). These rocks reacted by extreme exfoliation, at an average depth of 7.7 to 9.6 cm and a maximum depth of 20 cm. Scorched and blackened faces under the upper layer of spalls provide strong evidence that chalk breakdown took place at an early stage of the fire. The extreme response of the chalks can be explained by the laminar structure of the Nari, which served as planes of weakness for the rock destruction. Three years after the fire, the rocks continue to exfoliate and break down internally. As the harder surface of the Nari was removed, the more brittle underlying chalk is exposed to erosion. These flakes seem to play an important role in reforming the soil after the fire, especially by increasing the coarse particles percentage. These, in spite of the absence of vegetation cover, improve soil infiltration and percolation rates and cause long-term changes to the hydrological regime. It is difficult to estimate the frequency of high-intensity fires in the Carmel region over the past 2-3 million years, as well as the extension and density of the vegetation. It is even harder to assess the frequency of fires (and the destruction) of a single rock outcrop. Our findings show that rock outcrop may lose even 20 cm of its thickness in a single fire. This value, if accounted to the long run, can be responsible for a high percentage of the total denudation rate and therefore, in the mountainous carbonate slopes of the Mediterranean region, wildland fires may serve as extremely important factors in landscape evolution (Shtober-Zisu et al., 2015). Shtober-Zisu, N., Tessler, N., Tsatskin, A., & Greenbaum, N. (2015). Accelerated weathering of carbonate rocks following the 2010 wildfire on Mount Carmel, Israel. International Journal of Wildland Fire, 24(8): 1154-1167.

Emplacement dynamics and hydrothermal alteration of the Atengo ignimbrite, southern Sierra Madre Occidental, northwestern Mexico

NASA Astrophysics Data System (ADS)

Agarwal, Amar; Alva-Valdivia, L. M.; Rivas-Sánchez, M. L.; Herrero-Bervera, E.; Urrutia-Fucugauchi, J.; Espejel-García, V.

2017-12-01

The Sierra Madre Occidental is a thick continental arc related to the subduction of the Farallon plate beneath North America resulting in a very intense and widespread Cretaceous to Cenozoic magmatic and tectonic activity. The 28 My old Atengo ignimbrite outcrops in the southern Sierra Madre Occidental, northwestern Mexico. From 12 sites that belong to various pyroclastic and lava flows emplaced during two pulses in the Oligocene (ca. 32-28 Ma) and Early Miocene (ca. 24-20 Ma), 97 rock specimens were drilled. The mineralogical and rock magnetic properties of the Atengo ignimbrite are compared with the surrounding volcanic rocks to identify the eruption mechanism, and with the El Castillo Ignimbrite, Veracruz, Mexico, to understand the depositional conditions. The comparisons reveal that the Atengo ignimbrite erupted from a single source, but less violently than the El Castillo ignimbrite, and cooled rapidly, inhibiting the formation of subhedral grains. The source of the Atengo Ignimbrite was a Plinian-type eruption, and the characteristic mineralogical and textural properties of each flow are related to different stages of the Plinian-type eruption. Further more, hydrothermal fluids were active during the last stages of volcanism, and caused moderate to intense alteration, especially in the ignimbrites, where high permeability aided the movement of hydrothermal fluids.

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

NASA Astrophysics Data System (ADS)

Shamsuddin, A.

2017-10-01

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

Oxygen Isotopes and the Cooling History of the Mount Barcroft Area, Central White Mountains, Easternmost California

NASA Astrophysics Data System (ADS)

Ernst, W. G.; Rumble, D.

2001-12-01

The White-Inyo Range + Owens Valley marks the western limit of the Basin and Range province, directly east of the Sierra Nevada. At Mount Barcroft, mid-Mesozoic, alkaline, bimodal White Mountain Peak metavolcanic + metaclastic rocks on the N are separated from Lower Cambrian siliciclastic + carbonate metasedimentary strata on the S by the NE-trending Middle Jurassic Barcroft mafic granodioritic pluton. It consists of mineralogically/chemically intergradational gabbro/diorite, granodiorite, metadiorite, and alaskite. Eastward, the section is intruded by the Late Cretaceous, ternary-minimum McAfee Creek Granite. Ignoring altered dikes, bulk-rock analyses of plutonic rocks indicate that metaluminous, I-type rocks of the Barcroft comagmatic suite possess an av(12) d18O value of 7.5. Slightly peraluminous, apparently S-type granitic rocks sensu stricto of the McAfee Creek series have an av(8) d18O value of 8.6. Evidence is lacking for large-scale bulk-rock interaction with near-surface waters, suggesting intermediate crustal depths of intrusion and cooling for these plutons. Coexisting Barcroft minerals exhibit consistent oxygen isotopic partitioning from high to low d18O in the sequence quartz > plagioclase > K-feldspar >> amphibole = biotite. Wall-rock quartz and biotite are richer in 18O than analogous phases in the plutonic rocks, and show slightly greater fractionations than igneous counterparts. Along its borders, late-stage exchange with heated aqueous fluids, derived from recrystallized wall rocks due to emplacement of the Middle Jurassic magma, increased 18O/16O ratios of dikes, and some Barcroft igneous plagioclase and subsolidus tremolite-actinolite. Oxygen isotope geothermometry for Barcroft quartz-amphibole and quartz-biotite pairs yields broadly similar temperatures; the combined average of 13 pairs is 519oC. A single quartz-biotite pair analyzed from a Lower Cambrian quartzite within the inner metamorphic aureole of the Barcroft pluton yields a temperature of 511oC, in agreement with values based on wall-rock metamorphic parageneses. Barcroft quartz, feldspars, biotite, and clinoamphiboles were subjected to exchange with deuteric fluid, and re-equilibrated under subsolidus conditions. Quartz-plagioclase pairs from two Barcroft granodiorites possess similar temperatures of 519 and 515oC, so also re-equilibrated at subsolidus temperatures. Areal distributions for quartz-plagioclase, quartz-clinoamphibole, and quartz-biotite pairs reveal that annealing temperatures are lowest in axial portions of the Barcroft granodioritic pluton. Late Cretaceous emplacement of the McAfee Creek Granite had little effect on d18O values of Barcroft minerals and bulk rocks.

Ae2Sb2X4F2 (Ae = Sr, Ba): new members of the homologous series Ae2M(1+n)X(3+n)F2 designed from rock salt and fluorite 2D building blocks.

PubMed

Kabbour, Houria; Cario, Laurent

2006-03-20

We have designed new compounds within the homologous series Ae2F2M(1+n)X(3+n) (Ae = Sr, Ba; M = main group metal; n = integer) built up from the stacking of 2D building blocks of rock salt and fluorite types. By incrementally increasing the size of the rock salt 2D building blocks, we have obtained two new n = 1 members of this homologous series, namely, Sr2F2Sb2Se4 and Ba2F2Sb2Se4. We then succeeded in synthesizing these compounds using a high-temperature ceramic method. The structure refinements from the powder or single-crystal X-ray diffraction data confirmed presence of the expected alternating stacking of fluorite [Ae2F2] (Ae = Sr, Ba) and rock salt [Sb2Se4] 2D building blocks. However the Ba derivative shows a strong distortion of the [Sb2Se4] block and a concomitant change of the Sb atom coordination likely related to the lone-pair activity.

The role of the RhoA/ROCK pathway in gender-dependent differences in gastric smooth muscle contraction.

PubMed

Al-Shboul, Othman

2016-01-01

Gender-related differences in various gastric functions and diseases have been reported, with women having a higher prevalence of gastrointestinal disturbances than men. The aim of this study was to investigate sex-dependent differences in activation of the Rho-associated protein kinase (ROCK; RhoA/Rho kinase) pathway and muscle contraction in the stomach using single gastric smooth muscle cells (GSMC) from male and female Sprague-Dawley rats. Expression of ROCK1 and ROCK2 protein and acetylcholine (ACh)-induced activation of RhoA and ROCK were measured using a specifically designed enzyme-linked immunosorbent assay and activity assay kits, respectively. Contraction of a single GSMC was measured by scanning micrometry in the presence or absence of the ROCK inhibitor Y27632 dihydrochloride. ACh-induced activation of RhoA and ROCK and subsequent contraction were greater in male rats than in female rats but neither was related to differences in the expression of ROCK1 or ROCK2 or total RhoA amount. Most important, Y27632 inhibited and abolished differences in ACh-induced contraction in both sexes. In conclusion, increased ACh-induced contraction in the GSMC of male rats is attributable to greater RhoA/ROCK activation independent of differences in the expression of ROCK isoforms or total RhoA.

New Perspectives on Long Run-out Rock Avalanches: A Dynamic Analysis of 20 Events in the Vaigat Strait, West Greenland

NASA Astrophysics Data System (ADS)

Benjamin, J.; Rosser, N. J.; Dunning, S.; Hardy, R. J.; Karim, K.; Szczucinski, W.; Norman, E. C.; Strzelecki, M.; Drewniak, M.

2014-12-01

Risk assessments of the threat posed by rock avalanches rely upon numerical modelling of potential run-out and spreading, and are contingent upon a thorough understanding of the flow dynamics inferred from deposits left by previous events. Few records exist of multiple rock avalanches with boundary conditions sufficiently consistent to develop a set of more generalised rules for behaviour across events. A unique cluster of 20 large (3 x 106 - 94 x 106 m3) rock avalanche deposits along the Vaigat Strait, West Greenland, offers a unique opportunity to model a large sample of adjacent events sourced from a stretch of coastal mountains of relatively uniform geology and structure. Our simulations of these events were performed using VolcFlow, a geophysical mass flow code developed to simulate volcanic debris avalanches. Rheological calibration of the model was performed using a well-constrained event at Paatuut (AD 2000). The best-fit simulation assumes a constant retarding stress with a collisional stress coefficient (T0 = 250 kPa, ξ = 0.01), and simulates run-out to within ±0.3% of that observed. Despite being widely used to simulate rock avalanche propagation, other models, that assume either a Coulomb frictional or a Voellmy rheology, failed to reproduce the observed event characteristics and deposit distribution at Paatuut. We applied this calibration to 19 other events, simulating rock avalanche motion across 3D terrain of varying levels of complexity. Our findings illustrate the utility and sensitivity of modelling a single rock avalanche satisfactorily as a function of rheology, alongside the validity of applying the same parameters elsewhere, even within similar boundary conditions. VolcFlow can plausibly account for the observed morphology of a series of deposits emplaced by events of different types, although its performance is sensitive to a range of topographic and geometric factors. These exercises show encouraging results in the model's ability to simulate a series of events using a single set of parameters obtained by back-analysis of the Paatuut event alone. The results also hold important implications for our process understanding of rock avalanches in confined fjord settings, where correctly modelling material flux at the point of entry into the water is critical in tsunami generation.

Theory of wing rock

NASA Technical Reports Server (NTRS)

Hsu, C.-H.; Lan, C. E.

1985-01-01

Wing rock is one type of lateral-directional instabilities at high angles of attack. To predict wing rock characteristics and to design airplanes to avoid wing rock, parameters affecting wing rock characteristics must be known. A new nonlinear aerodynamic model is developed to investigate the main aerodynamic nonlinearities causing wing rock. In the present theory, the Beecham-Titchener asymptotic method is used to derive expressions for the limit-cycle amplitude and frequency of wing rock from nonlinear flight dynamics equations. The resulting expressions are capable of explaining the existence of wing rock for all types of aircraft. Wing rock is developed by negative or weakly positive roll damping, and sustained by nonlinear aerodynamic roll damping. Good agreement between theoretical and experimental results is obtained.

Increases to Biogenic Secondary Organic Aerosols from SO2 and NOx in the Southeastern US

NASA Astrophysics Data System (ADS)

Russell, L. M.; Liu, J.; Ruggeri, G.; Takahama, S.; Claflin, M. S.; Ziemann, P. J.; Lee, A.; Murphy, B.; Pye, H. O. T.; Ng, N. L.; McKinney, K. A.; Surratt, J. D.

2017-12-01

During the 2013 Southern Oxidant and Aerosol Study, Fourier Transform Infrared Spectroscopy (FTIR) and Aerosol Mass Spectrometer (AMS) measurements of submicron mass were collected at Look Rock, Tennessee, and Centreville, Alabama. The low NOx, low wind, little rain, and increased daytime isoprene emissions led to multi-day stagnation events at Look Rock that provided clear evidence of particle-phase sulfate enhancing biogenic secondary organic aerosol (bSOA) by selective uptake. Organic mass (OM) sources were apportioned as 42% "vehicle-related" and 54% bSOA, with the latter including "sulfate-related bSOA" that correlated to sulfate (r=0.72) and "nitrate-related bSOA" that correlated to nitrate (r=0.65). Single-particle mass spectra showed three composition types that corresponded to the mass-based factors with spectra cosine similarity of 0.93 and time series correlations of r>0.4. The vehicle-related OM with m/z 44 was correlated to black carbon, "sulfate-related bSOA" was on particles with high sulfate, and "nitrate-related bSOA" was on all particles. The similarity of the m/z spectra (cosine similarity=0.97) and the time series correlation (r=0.80) of the "sulfate-related bSOA" to the sulfate-containing single-particle type provide evidence for particle composition contributing to selective uptake of isoprene oxidation products onto particles that contain sulfate from power plants. Since Look Rock had much less NOx than Centreville, comparing the bSOA at the two sites provides an evaluation of the role of NOx for bSOA. CO and submicron sulfate and OM concentrations were 15-60 % higher at Centreville than at Look Rock but their time series had moderate correlations of r= 0.51, 0.54, and 0.47, respectively. However, NOx had no correlation (r=0.08) between the two sites. OM correlated with the higher NOx levels at Centreville but with O3 at Look Rock. OM sources identified by Positive Matrix Factorization had three very similar factors at both sites from FTIR, one of which was Biological Organic Aerosols. The FTIR spectrum for this factor is similar (cosine similarity > 0.6) to that of lab-generated particle mass from both isoprene and monoterpene with high NOx conditions from chamber experiments, providing verification of the reactions relevant to atmospheric conditions.

Petrology and geochemistry of lithic fragments separated from the Apollo 15 deep-drill core

NASA Technical Reports Server (NTRS)

Lindstrom, M. M.; Nielsen, R. L.; Drake, M. J.

1977-01-01

Petrological and geochemical analysis of lithic fragments separated from the Apollo 15 deep-drill core showed these fragments to fall into the essentially the same range of rock types as observed in surface soil samples and large rock samples. Three particles are singled out as being of special interest. One sample is a mare basalt containing extremely evolved phases. The particle may represent small-scale imperfect crystal/liquid separation in a lava flow. A green glass particle is not the ultramafic emerald green glass described from the Apollo 15 site, but rather an ANT-like light green color, and has a quite different chemical composition from the ultramafic variety. One mare basalt displays a positive Eu anomaly and is enriched in plagioclase relative to olivine plus pyroxene.

Veins in the northern part of the Boulder batholith, Montana

USGS Publications Warehouse

Pinckney, D.M.

1965-01-01

About 20 miles north of Butte and extending nearly to Helena, is an area of 350 square miles containing hundreds of veins and altered zones. The bedrock of the area is 1) late Cretaceous volcanic rocks, forerunners of the Boulder batholith, 2) the Boulder batholith of late Cretaceous to early Tertiary age and 3) two groups of Tertiary volcanic rocks lying on the eroded batholith. The veins are post-batholith and pre-Tertiary in age. The veins are largely either quartz-sulfide veins of mesothermal type or chalcedony veins of epithermal type. The relations of these two types of veins have been the subject of conflicting ideas for 60 years. Three workers have proposed three different genetic classifications. This report shows that the quartz veins and the chalcedony veins are closely related parts of a strongly zoned hypogene vein system. Strong zonal patterns were established using the grain size of quartz (or pyrite vs. carbonate in one district) as well as features of the altered rocks. The scale of the zoning ranges from single veins through groups of veins or mining districts to the entire mineralized area. Single veins are zoned around a core of coarse-grained quartz; the quartz outward from the core becoming progressively finer-grained. The cores are zoned around eight major centers and several lesser ones. The centers and their nearby related veins are assigned to central, intermediate, and peripheral zones. Nearly all of the veins around the edge of the mineralized area are chalcedony. Envelopes of altered rocks consist of seven major bands representing three major groups of constituents, aluminum silicates, iron-bearing minerals, and silica. Plagioclase altered successively to montomorillite, kaolinite, and sericite; potassium feldspar altered to sericite (aluminum silicate group). Biotite released iron which formed successively, iron oxides, iron-bearing carbonate, and pyrite (iron-bearing minerals). Excess silica formed silicified bands. Constituents for which no stable phase occurs were largely leached from the rocks. A model has been constructed showing the arrangement of zoned veins and altered rocks in which the minerals produced by alteration are arranged in bands on each side of the vein, similar to the Butte pattern. Along strike from the cores, the inner bands thin and pinch out against the vein so that the vein becomes enclosed successively in the next outer bands. The sequence of alteration minerals along the veins is sericite, kaolinite, and montmorillonite for the aluminum silicates; and pyrite, carbonate, and iron oxides for the iron-bearing minerals. Alteration is thought to be controlled by reactions between wallrock minerals and the pore solution. In the aluminum silicate reactions, H+ was added to the rock and Na+ and Ca++ were removed. Carbon and sulfur from the vein were added to iron of the wallrock to produce pyrite and iron carbonate. Carbon, sulfur, and hydrogen moved into the wallrock, while Ca++, Na+, and some SiO2 moved toward the vein along concentration or activity gradients. Temperatures during mineralization ranged from below 200? C to about 350? C.

Rock Tea extract (Jasonia glutinosa) relaxes rat aortic smooth muscle by inhibition of L-type Ca(2+) channels.

PubMed

Valero, Marta Sofía; Oliván-Viguera, Aida; Garrido, Irene; Langa, Elisa; Berzosa, César; López, Víctor; Gómez-Rincón, Carlota; Murillo, María Divina; Köhler, Ralf

2015-12-01

In traditional herbal medicine, Rock Tea (Jasonia glutinosa) is known for its prophylactic and therapeutic value in various disorders including arterial hypertension. However, the mechanism by which Rock Tea exerts blood pressure-lowering actions has not been elucidated yet. Our aim was to demonstrate vasorelaxing effects of Rock Tea extract and to reveal its possible action mechanism. Isometric myography was conducted on high-K+-precontracted rings from rat thoracic aorta and tested extracts at concentrations of 0.5-5 mg/ml. Whole-cell patch-clamp experiments were performed in rat aortic vascular smooth muscle cells (line A7r5) to determine blocking effects on L-type Ca(2+) channels. Rock Tea extract relaxed the aorta contracted by high [K+] concentration dependently with an EC50 of ≈2.4 mg/ml and produced ≈75 % relaxation at the highest concentration tested. The L-type Ca(2+) channel blocker, verapamil (10(-6) M), had similar effects. Rock Tea extract had no effect in nominally Ca(2+)-free high-K(+) buffer but significantly inhibited contractions to re-addition of Ca(2+). Rock Tea extract inhibited the contractions induced by the L-type Ca(2+) channel activator Bay K 8644 (10(-5) M) and by phenylephrine (10(-6) M). Rock Tea extract and Y-27632 (10(-6) M), Rho-kinase inhibitor, had similar effects and the respective effects were not additive. Patch-clamp experiments demonstrated that Rock Tea extract (2.5 mg/ml) virtually abolished L-type Ca(2+) currents in A7r5. We conclude that Rock Tea extract produced vasorelaxation of rat aorta and that this relaxant effect is mediated by inhibition of L-type Ca(2+) channels. Rock Tea extracts may be of phytomedicinal value for prevention and adjuvant treatment of hypertension and other cardiovascular diseases.

Petrogenesis of Cretaceous volcanic-intrusive complex from the giant Yanbei tin deposit, South China: Implication for multiple magma sources, tin mineralization, and geodynamic setting

NASA Astrophysics Data System (ADS)

Li, Qian; Zhao, Kui-Dong; Lai, Pan-Chen; Jiang, Shao-Yong; Chen, Wei

2018-01-01

The giant Yanbei tin ore deposit is the largest porphyry-type tin deposit in South China. The orebodies are hosted by the granite porphyry in the central part of the Yanbei volcanic basin in southern Jiangxi Province. The Yanbei volcanic-intrusive complex mainly consists of dacitic-rhyolitic volcanic rocks, granite, granite porphyry and diabase dikes. In previous papers, the granite porphyry was considered as subvolcanic rocks, which came from the same single magma chamber with the volcanic rocks. In this study, zircon U-Pb ages and Hf isotope data, as well as whole-rock geochemical and Sr-Nd isotopic compositions of different magmatic units in the Yanbei complex are reported. Geochronologic results show that various magmatic units have different formation ages. The dacite yielded a zircon U-Pb age of 143 ± 1 Ma, and the granite porphyry has the emplacement age of 138 ± 1 Ma. Diabase dikes which represented the final stage of magmatism, yielded a zircon U-Pb age of 128 ± 1 Ma. Distinctive whole rock Sr-Nd and zircon Hf isotopic compositions suggest that these magmatic units were derived from different magma sources. The volcanic rocks were mainly derived from the partial melting of Paleoproterozoic metasedimentary rocks without additions of mantle-derived magma. The granite porphyry has an A-type geochemical affinity, and was derived from remelting of Paleo-Mesoproterozoic crustal source with involvement of a subordinate mantle-derived magma. The granite porphyry is also a typical stanniferous granite with high F (4070-6090 ppm) and Sn (7-39 ppm) contents. It underwent strongly crystal fractionation of plagioclase, K-feldspar, and accessory minerals (like apatite, Fe-Ti oxides), which may contribute to the tin mineralization. The diabase was derived by partial melting of enriched lithospheric mantle which had been metasomatised by slab-derived fluids. The change of magmatic sources reflected an increasing extensional tectonic environment, perhaps induced by slab rollback of subducted paleo-Pacific plate.

The Research on Tunnel Surrounding Rock Classification Based on Geological Radar and Probability Theory

NASA Astrophysics Data System (ADS)

Xiao Yong, Zhao; Xin, Ji Yong; Shuang Ying, Zuo

2018-03-01

In order to effectively classify the surrounding rock types of tunnels, a multi-factor tunnel surrounding rock classification method based on GPR and probability theory is proposed. Geological radar was used to identify the geology of the surrounding rock in front of the face and to evaluate the quality of the rock face. According to the previous survey data, the rock uniaxial compressive strength, integrity index, fissure and groundwater were selected for classification. The related theories combine them into a multi-factor classification method, and divide the surrounding rocks according to the great probability. Using this method to classify the surrounding rock of the Ma’anshan tunnel, the surrounding rock types obtained are basically the same as those of the actual surrounding rock, which proves that this method is a simple, efficient and practical rock classification method, which can be used for tunnel construction.

Source of boron in the Palokas gold deposit, northern Finland: evidence from boron isotopes and major element composition of tourmaline

NASA Astrophysics Data System (ADS)

Ranta, Jukka-Pekka; Hanski, Eero; Cook, Nick; Lahaye, Yann

2017-06-01

The recently discovered Palokas gold deposit is part of the larger Rompas-Rajapalot gold-mineralized system located in the Paleoproterozoic Peräpohja Belt, northern Finland. Tourmaline is an important gangue mineral in the Palokas gold mineralization. It occurs as tourmalinite veins and as tourmaline crystals in sulfide-rich metasomatized gold-bearing rocks. In order to understand the origin of tourmaline in the gold-mineralized rocks, we have investigated the major element chemistry and boron isotope composition of tourmaline from three areas: (1) the Palokas gold mineralization, (2) a pegmatitic tourmaline granite, and (3) the evaporitic Petäjäskoski Formation. Based on textural evidence, tourmaline in gold mineralization is divided into two different types. Type 1 is located within the host rock and is cut by rock-forming anthophyllite crystals. Type 2 occurs in late veins and/or breccia zones consisting of approximately 80% tourmaline and 20% sulfides, commonly adjacent to quartz veins. All the studied tourmaline samples belong to the alkali-group tourmaline and can be classified as dravite and schorl. The δ11B values of the three localities lie in the same range, from 0 to -4‰. Tourmaline from the Au mineralization and from the Petäjäskoski Formation has similar compositional trends. Mg is the major substituent for Al; inferred low Fe3+/Fe2+ ratios and Na values (<0.8 atoms per formula unit (apfu)) of all tourmaline samples suggest that they precipitated from reduced, low-salinity fluids. Based on the similar chemical and boron isotope composition and the Re-Os age of molybdenite related to the tourmaline-sulfide-quartz veins, we propose that the tourmaline-forming process is a result of a single magmatic-hydrothermal event related to the extensive granite magmatism at around 1.79-1.77 Ga. Tourmaline was crystallized throughout the hydrothermal process, which resulted in the paragenetic variation between type 1 and type 2. The close association of tourmaline and gold suggests that the gold precipitated from the same boron-rich source as tourmaline.

Solubilization of phosphorus from phosphate rocks with Acidithiobacillus thiooxidans following a growing-then-recovery process.

PubMed

Calle-Castañeda, Susana M; Márquez-Godoy, Marco A; Hernández-Ortiz, Juan P

2017-12-29

Phosphorus is an essential nutrient for the synthesis of biomolecules and is particularly important in agriculture, as soils must be constantly supplemented with its inorganic form to ensure high yields and productivity. In this paper, we propose a process to solubilize phosphorus from phosphate rocks, where Acidithiobacillus thiooxidans cultures are pre-cultivated to foster the acidic conditions for bioleaching-two-step "growing-then-recovery"-. Our method solubilizes 100% of phosphorus, whereas the traditional process without pre-cultivation-single-step "growing-and-recovery"-results in a maximum of 56% solubilization. As a proof of principle, we demonstrate that even at low concentrations of the phosphate rock, 1% w/v, the bacterial culture is unviable and biological activity is not observed during the single-step process. On the other hand, in our method, the bacteria are grown without the rock, ensuring high acid production. Once pH levels are below 0.7, the mineral is added to the culture, resulting in high yields of biological solubilization. According to the Fourier Transform Infrared Spectroscopy spectrums, gypsum is the dominant phosphate phase after both the single- and two-step methods. However, calcite and fluorapatite, dominant in the un-treated rock, are still present after the single-step, highlighting the differences between the chemical and the biological methods. Our process opens new avenues for biotechnologies to recover phosphorus in tropical soils and in low-grade phosphate rock reservoirs.

Characterization of rock populations on planetary surfaces - Techniques and a preliminary analysis of Mars and Venus

NASA Technical Reports Server (NTRS)

Garvin, J. B.; Mouginis-Mark, P. J.; Head, J. W.

1981-01-01

A data collection and analysis scheme developed for the interpretation of rock morphology from lander images is reviewed with emphasis on rock population characterization techniques. Data analysis techniques are also discussed in the context of identifying key characteristics of a rock that place it in a single category with similar rocks. Actual rock characteristics observed from Viking and Venera lander imagery are summarized. Finally, some speculations regarding the block fields on Mars and Venus are presented.

Prediction of carbonate rock type from NMR responses using data mining techniques

NASA Astrophysics Data System (ADS)

Gonçalves, Eduardo Corrêa; da Silva, Pablo Nascimento; Silveira, Carla Semiramis; Carneiro, Giovanna; Domingues, Ana Beatriz; Moss, Adam; Pritchard, Tim; Plastino, Alexandre; Azeredo, Rodrigo Bagueira de Vasconcellos

2017-05-01

Recent studies have indicated that the accurate identification of carbonate rock types in a reservoir can be employed as a preliminary step to enhance the effectiveness of petrophysical property modeling. Furthermore, rock typing activity has been shown to be of key importance in several steps of formation evaluation, such as the study of sedimentary series, reservoir zonation and well-to-well correlation. In this paper, a methodology based exclusively on the analysis of 1H-NMR (Nuclear Magnetic Resonance) relaxation responses - using data mining algorithms - is evaluated to perform the automatic classification of carbonate samples according to their rock type. We analyze the effectiveness of six different classification algorithms (k-NN, Naïve Bayes, C4.5, Random Forest, SMO and Multilayer Perceptron) and two data preprocessing strategies (discretization and feature selection). The dataset used in this evaluation is formed by 78 1H-NMR T2 distributions of fully brine-saturated rock samples from six different rock type classes. The experiments reveal that the combination of preprocessing strategies with classification algorithms is able to achieve a prediction accuracy of 97.4%.

Cyclic and Fatigue Behaviour of Rock Materials: Review, Interpretation and Research Perspectives

NASA Astrophysics Data System (ADS)

Cerfontaine, B.; Collin, F.

2018-02-01

The purpose of this paper is to provide a comprehensive state of the art of fatigue and cyclic loading of natural rock materials. Papers published in the literature are classified and listed in order to ease bibliographical review, to gather data (sometimes contradictory) on classical experimental results and to analyse the main interpretation concepts. Their advantages and limitations are discussed, and perspectives for further work are highlighted. The first section summarises and defines the different experimental set-ups (type of loading, type of experiment) already applied to cyclic/fatigue investigation of rock materials. The papers are then listed based on these different definitions. Typical results are highlighted in next section. Fatigue/cyclic loading mainly results in accumulation of plastic deformation and/or damage cycle after cycle. A sample cyclically loaded at constant amplitude finally leads to failure even if the peak load is lower than its monotonic strength. This subcritical crack is due to a diffuse microfracturing and decohesion of the rock structure. The third section reviews and comments the concepts used to interpret the results. The fatigue limit and S- N curves are the most common concepts used to describe fatigue experiments. Results published from all papers are gathered into a single figure to highlight the tendency. Predicting the monotonic peak strength of a sample is found to be critical in order to compute accurate S- N curves. Finally, open questions are listed to provide a state of the art of grey areas in the understanding of fatigue mechanisms and challenges for the future.

Reverse Polarity Magnetized Melt Rocks from the Cretaceous/Tertiary Chicxulub Structure, Yucatan Peninsula, Mexico

NASA Technical Reports Server (NTRS)

Urrutia-Fucugauchi, J.; Marin, Luis; Sharpton, Virgil L.

1994-01-01

We report paleomagnetic results for core samples of the breccia and andesitic rocks recovered from the Yucatan-6 Petrolcos Mexicanos exploratory well within the Chicxulub structure (about 60 km SSW from its center), northern Yucatan, Mexico. A previous study has shown that the rocks studied contain high iridium levels and shocked breccia clasts and an Ar/Ar date of 65.2 +/- 0.4 Ma. Andesitic rocks are characterized by stable single-component magnetizations with a mean inclination of -42.6 deg +/- 2.4 deg. Breccias present a complex paleomagnetic record characterized by multivectorial magnetizations with widely different initial NRM inclinations. However, after alternating field demagnetization, well defined characteristic components with upward inclinations are defined. IRM acquisition experiments, comparison of IRM and NRM coercivity spectra and the single component magnetization of the andesitic rocks indicate the occurrence of iron-rich titanomagnetites of single or pseudo-single domain states as the dominant magnetic carriers. Mean inclinations from the andesitic rocks and most of the breccia samples give a mean inclination of about -40 deg to -45 deg, indicating a reverse polarity for the characteristic magnetization that is consistent with geomagnetic chron 29R, which spans the Cretaceous/Tertiary (K/T) boundary. The inclination is also consistent with the expected value (and corresponding paleolatitude) for the site estimated from the reference polar wander curve for North America. We suggest that the characteristic magnetizations for the andesitic and breccia rocks are the result of shock heating at the time of formation of the impact structure and that the age, polarity and pateolatitude are consistent with a time at the K/T boundary.

Orientation Uncertainty of Structures Measured in Cored Boreholes: Methodology and Case Study of Swedish Crystalline Rock

NASA Astrophysics Data System (ADS)

Stigsson, Martin

2016-11-01

Many engineering applications in fractured crystalline rocks use measured orientations of structures such as rock contact and fractures, and lineated objects such as foliation and rock stress, mapped in boreholes as their foundation. Despite that these measurements are afflicted with uncertainties, very few attempts to quantify their magnitudes and effects on the inferred orientations have been reported. Only relying on the specification of tool imprecision may considerably underestimate the actual uncertainty space. The present work identifies nine sources of uncertainties, develops inference models of their magnitudes, and points out possible implications for the inference on orientation models and thereby effects on downstream models. The uncertainty analysis in this work builds on a unique data set from site investigations, performed by the Swedish Nuclear Fuel and Waste Management Co. (SKB). During these investigations, more than 70 boreholes with a maximum depth of 1 km were drilled in crystalline rock with a cumulative length of more than 34 km including almost 200,000 single fracture intercepts. The work presented, hence, relies on orientation of fractures. However, the techniques to infer the magnitude of orientation uncertainty may be applied to all types of structures and lineated objects in boreholes. The uncertainties are not solely detrimental, but can be valuable, provided that the reason for their presence is properly understood and the magnitudes correctly inferred. The main findings of this work are as follows: (1) knowledge of the orientation uncertainty is crucial in order to be able to infer correct orientation model and parameters coupled to the fracture sets; (2) it is important to perform multiple measurements to be able to infer the actual uncertainty instead of relying on the theoretical uncertainty provided by the manufacturers; (3) it is important to use the most appropriate tool for the prevailing circumstances; and (4) the single most important parameter to decrease the uncertainty space is to avoid drilling steeper than about -80°.

Crystal preferred orientation of amphibole and implications for seismic anisotropy in the crust

NASA Astrophysics Data System (ADS)

Jung, Haemyeong

2016-04-01

Strong seismic anisotropy is often observed in the middle to lower crust and it has been considered to be originated from the crystal preferred orientation (CPO) of anisotropic minerals such as amphibole. Amphibolite is one of the dominant rocks in the middle to lower crust. In this study, crystal preferred orientations of hornblende in amphibolites at Yeoncheon and Chuncheon areas in South Korea were determined by using the electron backscattered diffraction (EBSD)/SEM with HKL Channel 5 software. In Yeoncheon area, hornblende showed two types of CPOs. Type-I CPO is characterized as (100) poles of hornblende aligned subnormal to foliation and [001] axes aligned subparallel to lineation. Type-II CPO is characterized as (100) poles of hornblende aligned subnormal to foliation and (010) poles aligned subparallel to lineation (refer to Ko and Jung, 2015, Nature Communications). In Chuncheon area, three types of CPOs of hornblende were observed. In addition to the type-I and -II CPOs described above, type-III CPO of hornblende was observed in Chuncheon area and it is characterized as (100) poles of hornblende aligned subnormal to foliation and both [001] axes and (010) poles aligned as a girdle subparallel to foliation. Using the observed CPO and the single crystal elastic constant of hornblende, seismic anisotropy of hornblende was calculated. Seismic anisotropy of P-wave was strong in the range of 10.2 - 13.5 %. Seismic anisotropy of S-wave was also strong in the range of 6.9 - 11.2 %. These results show that hornblende deformed in nature can produce a strong CPO, resulting in a strong seismic anisotropy in the middle to lower crust. Taking into account of the CPO of plagioclase in the rock, seismic anisotropies of whole rock turned out to be maximum P-wave anisotropy (Vp) of 9.8% and maximum S-wave anisotropy (Vs) of 8.2%. Therefore, strong seismic anisotropy found in the middle to lower crust in nature can be attributed to the CPO of hornblende in amphibolite.

Rock falls from Glacier Point above Camp Curry, Yosemite National Park, California

USGS Publications Warehouse

Wieczorek, Gerald F.; Snyder, James B.

1999-01-01

A series of rock falls from the north face of Glacier Point above Camp Curry, Yosemite National Park, California, have caused reexamination of the rock-fall hazard because beginning in June, 1999 a system of cracks propagated through a nearby rock mass outlining a future potential rock fall. If the estimated volume of the potential rock fall fails as a single piece, there could be a risk from rock-fall impact and airborne rock debris to cabins in Camp Curry. The role of joint plane orientation and groundwater pressure in the fractured rock mass are discussed in light of the pattern of developing cracks and potential modes of failure.

Hydrogen in rocks: an energy source for deep microbial communities

NASA Technical Reports Server (NTRS)

Freund, Friedemann; Dickinson, J. Thomas; Cash, Michele

2002-01-01

To survive in deep subsurface environments, lithotrophic microbial communities require a sustainable energy source such as hydrogen. Though H2 can be produced when water reacts with fresh mineral surfaces and oxidizes ferrous iron, this reaction is unreliable since it depends upon the exposure of fresh rock surfaces via the episodic opening of cracks and fissures. A more reliable and potentially more voluminous H2 source exists in nominally anhydrous minerals of igneous and metamorphic rocks. Our experimental results indicate that H2 molecules can be derived from small amounts of H2O dissolved in minerals in the form of hydroxyl, OH- or O3Si-OH, whenever such minerals crystallized in an H2O-laden environment. Two types of experiments were conducted. Single crystal fracture experiments indicated that hydroxyl pairs undergo an in situ redox conversion to H2 molecules plus peroxy links, O3Si/OO\\SiO3. While the peroxy links become part of the mineral structure, the H2 molecules diffused out of the freshly fractured mineral surfaces. If such a mechanism occurred in natural settings, the entire rock column would become a volume source of H2. Crushing experiments to facilitate the outdiffusion of H2 were conducted with common crustal igneous rocks such as granite, andesite, and labradorite. At least 70 nmol of H2/g diffused out of coarsely crushed andesite, equivalent at standard pressure and temperature to 5,000 cm3 of H2/m3 of rock. In the water-saturated, biologically relevant upper portion of the rock column, the diffusion of H2 out of the minerals will be buffered by H2 saturation of the intergranular water film.

The razor's edge: Australian rock music impairs men's performance when pretending to be a surgeon.

PubMed

Fancourt, Daisy; Burton, Thomas Mw; Williamon, Aaron

2016-12-12

Over the past few decades there has been interest in the role of music in the operating theatre. However, despite many reported benefits, a number of potentially harmful effects of music have been identified. This study aimed to explore the effects of rock and classical music on surgical speed, accuracy and perceived distraction when performing multiorgan resection in the board game Operation. Single-blind, three-arm, randomised controlled trial. Imperial Festival, London, May 2016. Members of the public (n = 352) aged ≥ 16 years with no previous formal surgical training or hearing impairments. Participants were randomised to listen through noise-cancelling headphones to either the sound of an operating theatre, rock music or classical music. Participants were then invited to remove three organs from the board game patient, Cavity Sam, using surgical tweezers. Time taken (seconds) to remove three organs from Cavity Sam; the number of mistakes made in performing the surgery; and perceived distraction, rated on a five-point Likert-type scale from 1 (not at all distracting) to 5 (very distracting). Rock music impairs the performance of men but not women when undertaking complex surgical procedures in the board game Operation, increasing the time taken to operate and showing a trend towards more surgical mistakes. In addition, classical music was associated with lower perceived distraction during the game, but this effect was attenuated when factoring in how much people liked the music, with suggestions that only people who particularly liked the music of Mozart found it beneficial. Rock music (specifically Australian rock music) appears to have detrimental effects on surgical performance. Men are advised not to listen to rock music when either operating or playing board games.

Characterizing flow in oil reservoir rock using SPH: absolute permeability

NASA Astrophysics Data System (ADS)

Holmes, David W.; Williams, John R.; Tilke, Peter; Leonardi, Christopher R.

2016-04-01

In this paper, a three-dimensional smooth particle hydrodynamics (SPH) simulator for modeling grain scale fluid flow in porous rock is presented. The versatility of the SPH method has driven its use in increasingly complex areas of flow analysis, including flows related to permeable rock for both groundwater and petroleum reservoir research. While previous approaches to such problems using SPH have involved the use of idealized pore geometries (cylinder/sphere packs etc), in this paper we detail the characterization of flow in models with geometries taken from 3D X-ray microtomographic imaging of actual porous rock; specifically 25.12 % porosity dolomite. This particular rock type has been well characterized experimentally and described in the literature, thus providing a practical `real world' means of verification of SPH that will be key to its acceptance by industry as a viable alternative to traditional reservoir modeling tools. The true advantages of SPH are realized when adding the complexity of multiple fluid phases, however, the accuracy of SPH for single phase flow is, as yet, under developed in the literature and will be the primary focus of this paper. Flow in reservoir rock will typically occur in the range of low Reynolds numbers, making the enforcement of no-slip boundary conditions an important factor in simulation. To this end, we detail the development of a new, robust, and numerically efficient method for implementing no-slip boundary conditions in SPH that can handle the degree of complexity of boundary surfaces, characteristic of an actual permeable rock sample. A study of the effect of particle density is carried out and simulation results for absolute permeability are presented and compared to those from experimentation showing good agreement and validating the method for such applications.

Facies analysis of Late Proterozoic through Lower Cambrian rocks of the Death Valley regional ground-water system and surrounding areas, Nevada and California

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

Sweetkind, D.S.; White, D.K.

Late Proterozoic through Lower Cambrian rocks in the southern Great Basin form a westward-thickening wedge of predominantly clastic deposits that record deposition on the early western shelf edge of western North America (Stewart and Poole, 1974; Poole and others, 1992). Regional analyses of geologic controls on ground-water flow in the southern Great Basin typically combined lithostratigraphic units into more general hydrogeologic units that have considerable lateral extent and distinct hydrologic properties. The Late Proterozoic through Lower Cambrian rocks have been treated as a single hydrogeologic unit, named the lower clastic aquitard (Winograd and Thordarson, 1975) or the quartzite confining unitmore » (Laczniak and others, 1996), that serves as the hydrologic basement to the flow system. Although accurate in a general sense, this classification ignores well-established facies relations within these rocks that might increase bedrock permeability and locally influence ground-water flow . This report presents a facies analysis of Late Proterozoic through Lower Cambrian rocks (hereafter called the study interval) in the Death Valley regional ground-water flow system - that portion of the southern Great Basin that includes Death Valley, the Nevada Test Site, and the potential high-level nuclear waste underground repository at Yucca Mountain (fig. 1). The region discussed in this report, hereafter called the study area, covers approximately 100,000 km2 (lat 35 degrees-38 degrees 15'N., long 115 degrees-118 degrees W.). The purpose of this analysis is to provide a general documentation of facies transitions within the Late Proterozoic through Lower Cambrian rocks in order to provide an estimate of material properties (via rock type, grain size, and bedding characteristics) for specific hydrogeologic units to be included in a regional ground-water flow model.« less

Classification of hydrogeologic areas and hydrogeologic flow systems in the basin and range physiographic province, southwestern United States

USGS Publications Warehouse

Anning, David W.; Konieczki, Alice D.

2005-01-01

The hydrogeology of the Basin and Range Physiographic Province in parts of Arizona, California, New Mexico, Utah, and most of Nevada was classified at basin and larger scales to facilitate information transfer and to provide a synthesis of results from many previous hydrologic investigations. A conceptual model for the spatial hierarchy of the hydrogeology was developed for the Basin and Range Physiographic Province and consists, in order of increasing spatial scale, of hydrogeologic components, hydrogeologic areas, hydrogeologic flow systems, and hydrogeologic regions. This hierarchy formed a framework for hydrogeologic classification. Hydrogeologic areas consist of coincident ground-water and surface-water basins and were delineated on the basis of existing sets of basin boundaries that were used in past investigations by State and Federal government agencies. Within the study area, 344 hydrogeologic areas were identified and delineated. This set of basins not only provides a framework for the classification developed in this report, but also has value for regional and subregional purposes of inventory, study, analysis, and planning throughout the Basin and Range Physiographic Province. The fact that nearly all of the province is delineated by the hydrogeologic areas makes this set well suited to support regional-scale investigations. Hydrogeologic areas are conceptualized as a control volume consisting of three hydrogeologic components: the soils and streams, basin fill, and consolidated rocks. The soils and streams hydrogeologic component consists of all surface-water bodies and soils extending to the bottom of the plant root zone. The basin-fill hydrogeologic component consists of unconsolidated and semiconsolidated sediment deposited in the structural basin. The consolidated-rocks hydrogeologic component consists of the crystalline and sedimentary rocks that form the mountain blocks and basement rock of the structural basin. Hydrogeologic areas were classified into 19 groups through a cluster analysis of 8 characteristics of each area's hydrologic system. Six characteristics represented the inflows and outflows of water through the soils and streams, basin fill, and consolidated rocks, and can be used to determine the hydrogeologic area's position in a hydrogeologic flow system. Source-, link-, and sink-type hydrogeologic areas have outflow but not inflow, inflow and outflow, and inflow but not outflow, respectively, through one or more of the three hydrogeologic components. Isolated hydrogeologic areas have no inflow or outflow through any of the three hydrogeologic components. The remaining two characteristics are indexes that represent natural recharge and discharge processes and anthropogenic recharge and discharge processes occurring in the hydrogeologic area. Of the 19 groups of hydrogeologic areas, 1 consisted of predominantly isolated-type hydrogeologic areas, 7 consisted of source-type hydrogeologic areas, 9 consisted of link-type hydrogeologic areas, and 2 consisted of sink-type hydrogeologic areas. Groups comprising the source-, link-, and sink-type hydrogeologic areas can be distinguished between each other on the basis of the hydrogeologic component(s) through which interbasin flow occurs, as well as typical values for the two indexes. Conceptual models of the hydrologic systems of a representative hydrogeologic area for each group were developed to help distinguish groups and to synthesize the variation in hydrogeologic systems in the Basin and Range Physiographic Province. Hydrogeologic flow systems consist of either a single isolated hydrogeologic area or a series of multiple hydrogeologic areas that are hydraulically connected through interbasin flows. A total of 54 hydrogeologic flow systems were identified and classified into 9 groups. One group consisted of single isolated hydrogeologic areas. The remaining eight groups consisted of multiple hydrogeologic areas and were distinguished o

10 CFR 960.3-2-1 - Site screening for potentially acceptable sites.

Code of Federal Regulations, 2011 CFR

2011-01-01

... that contain rock formations of suitable depth, thickness, and lateral extent and have structural... require diversity of geohydrologic settings and rock types and consideration of regionality, as specified... provisions for diversity of geohydrologic settings, diversity of rock types, and regionality (§§ 960.3-1-1...

Volcanic mixed avalanches: a distinct eruption-triggered mass-flow process at snow-clad volcanoes

USGS Publications Warehouse

Pierson, T.C.; Janda, R.J.

1994-01-01

A generally unrecognized type of pyroclastic deposit was produced by rapid avalanches of intimately mixed snow and hot pyroclastic debris during eruptions at Mount St. Helens, Nevado del Ruiz, and Redoubt Volcano between 1982 and 1989. These "mixed avalanches' traveled as far as 14 km at velocities up to ~27 m/s, involved as much as 107 m3 of rock and ice, and left unmelted deposits of single flow units as thick as 5 m. During flow downslope, heat transfer from hot rocks to snow produced meltwater that partially saturated the mixtures, apparently giving these mixed avalanches mobilities equal to or greater than those of "dry' debris avalanches of similar volume. After melting and desiccation, the deposits are highly susceptible to erosion and unlikely to be well preserved in the stratigraphic record. -Authors

Compositions of Normal and Anomalous Eucrite-Type Mafic Achondrites

NASA Technical Reports Server (NTRS)

Mittlefehldt, D. W.; Peng, Z. X.; Mertzman, S. A.

2016-01-01

The most common asteroidal igneous meteorites are eucrite-type mafic achondrites - basalts and gabbros composed of ferroan pigeonite, ferroan augite, calcic plagioclase, silica, ilmenite, troilite, Ca-phosphate, chromite and Fe-metal. These rocks are thought to have formed on a single asteroid along with howardites and diogenites. However, high precision O-isotopic analyses have shown that some mafic achondrites have small, well-resolved, non-mass-dependent differences that have been interpreted as indicating derivation from different asteroids. Some of these O-anomalous mafic achondrites also have anomalous petrologic characteristics, strengthening the case that they hail from distinct parent asteroids. We present the results of bulk compositional studies of a suite of normal and anomalous eucrite-type basalts and cumulate gabbros.

Processes of high-T fluid-rock interaction during gold mineralization in carbonate-bearing metasediments: the Navachab gold deposit, Namibia

NASA Astrophysics Data System (ADS)

Dziggel, A.; Wulff, K.; Kolb, J.; Meyer, F. M.

2009-08-01

The Navachab gold deposit in the Damara belt of central Namibia is hosted by a near-vertical sequence of amphibolite facies shelf-type metasediments, including marble, calc-silicate rock, and biotite schist. Petrologic and geochemical data were collected in the ore, alteration halos, and the wall rock to evaluate transport of elements and interaction between the wall rock and the mineralizing fluid. The semi-massive sulfide lenses and quartz-sulfide veins are characterized by a complex polymetallic ore assemblage, comprising pyrrhotite, chalcopyrite, sphalerite, and arsenopyrite, native bismuth, gold, bismuthinite, and bismuth tellurides. Mass balance calculations indicate the addition of up to several orders of magnitude of Au, Bi, As, Ag, and Cu. The mineralized zones also record up to eightfold higher Mn and Fe concentrations. The semi-massive sulfide lenses are situated in the banded calc-silicate rock. Petrologic and textural data indicate that they represent hydraulic breccias that contain up to 50 vol.% ore minerals, and that are dominated by a high-temperature (T) alteration assemblage of garnet-clinopyroxene-K-feldspar-quartz. The quartz-sulfide veins crosscut all lithological units. Their thickness and mineralogy is strongly controlled by the composition and rheological behavior of the wall rocks. In the biotite schist and calc-silicate rock, they are up to several decimeters thick and quartz-rich, whereas in the marble, the same veins are only a few millimeters thick and dominated by sulfides. The associated alteration halos comprise (1) an actinolite-quartz alteration in the biotite schist, (2) a garnet-clinopyroxene-K-feldspar-quartz alteration in the marble and calc-silicate rock, and (3) a garnet-biotite alteration that is recorded in all rock types except the marble. The hydrothermal overprint was associated with large-scale carbonate dissolution and a dramatic increase in CO2 in the ore fluid. Decarbonation of wall rocks, as well as a low REE content of the ore fluid resulted in the mobilization of the REE, and the decoupling of the LREE from the HREE. The alteration halos not only parallel the mineralized zones, but may also follow up single layers away from the mineralization. Alteration is far more pronounced facing upward, indicating that the rocks were steep when veining occurred. The petrologic and geochemical data indicate that the actinolite-quartz- and garnet-clinopyroxene-K-feldspar-quartz alterations formed in equilibrium with a fluid (super-) saturated in Si, and were mainly controlled by the composition of the wall rocks. In contrast, the garnet-biotite alteration formed by interaction with a fluid undersaturated in Si, and was mainly controlled by the fluid composition. This points to major differences in fluid-rock ratios and changes in fluid composition during alteration. The alteration systematics and geometry of the hydrothermal vein system are consistent with cyclic fluctuations in fluid pressure during fault valve action.

Characterization of Possible Carbonatites in Southeast Missouri

NASA Astrophysics Data System (ADS)

Shavers, E. J.; Wulamu, A.; Encarnacion, J. P.; Luetkemeyer, P. B.

2014-12-01

Carbonatite is an igneous rock containing greater than 50% carbonate minerals. These rocks are the most common host of REE mineralization and may contain other economic deposits such as uranium, fluorine and niobium. Several researchers have mentioned the presence of a carbonatite phase interspersed among the olivine melilitite-alnöite dikes and diatremes of southeast Missouri, yet a comprehensive validation of this occurrence has, so far, remained elusive. Here we present petrographic, cathodoluminescence, stable isotope and Vis-NIR analysis which support the presence of a carbonatite magma. We identify apparently single generation calcite groundmass surrounding country rock xenoliths and olivine-cored mafic spheroids altered to carbonate and opaque minerals. We present stable isotope data for twenty samples of intrusive and country rock from across the study area. δ18O values for all rock types exhibit little variation with values between 21.9 ‰ and 28.1 ‰ (VSMOW), possibly the result of outgassing during emplacement. Measured δ13C values of (1) carbonate country rocks are between -0.1 ‰ and -2.9 ‰ (VPDB), (2) ultramafic and carbonate-rich mafic rocks range from -3.0 ‰ to -4.6 ‰ (VPDB) and (3) carbonate-rich rocks with volcanic textures, as well as carbonate veins within mafic rocks, fall between -5.4 ‰ to -8.2 ‰ (VPDB). We suggest that this data and initial petrographic observations indicate (1) limited fluid-rock interaction as the host rock clasts have retained their original isotopic signature, (2) an initial ultramafic phase enriched in 13C by a small amount of sedimentary rock due to low initial C content, (3) mantle sourced carbonate fluids entraining fragments of the ultramafic phase and xenoliths. However, future electron microprobe studies may allow us to further constrain the causes for the observed isotopic shifts. We compare laboratory reflectance measurements of a dolomitic intrusive and adjacent dolomite country rock. Absorption bands in the 0.42-1.35 and 2.2-2.4 μm regions indicate unique Si, Fe, Mg, Al and possibly Cr mineralization in the intrusive rock. These features may indicate higher chemical content in addition to, or alternately, intrusive specific mineralogy. This data may allow for future carbonatite identification using remote imaging spectroscopy.

Spatiotemporal complexity of 2-D rupture nucleation process observed by direct monitoring during large-scale biaxial rock friction experiments

NASA Astrophysics Data System (ADS)

Fukuyama, Eiichi; Tsuchida, Kotoyo; Kawakata, Hironori; Yamashita, Futoshi; Mizoguchi, Kazuo; Xu, Shiqing

2018-05-01

We were able to successfully capture rupture nucleation processes on a 2-D fault surface during large-scale biaxial friction experiments using metagabbro rock specimens. Several rupture nucleation patterns have been detected by a strain gauge array embedded inside the rock specimens as well as by that installed along the edge walls of the fault. In most cases, the unstable rupture started just after the rupture front touched both ends of the rock specimen (i.e., when rupture front extended to the entire width of the fault). In some cases, rupture initiated at multiple locations and the rupture fronts coalesced to generate unstable ruptures, which could only be detected from the observation inside the rock specimen. Therefore, we need to carefully examine the 2-D nucleation process of the rupture especially when analyzing the data measured only outside the rock specimen. At least the measurements should be done at both sides of the fault to identify the asymmetric rupture propagation on the fault surface, although this is not perfect yet. In the present experiment, we observed three typical types of the 2-D rupture propagation patterns, two of which were initiated at a single location either close to the fault edge or inside the fault. This initiation could be accelerated by the free surface effect at the fault edge. The third one was initiated at multiple locations and had a rupture coalescence at the middle of the fault. These geometrically complicated rupture initiation patterns are important for understanding the earthquake nucleation process in nature.

Yatesville Lake, Big Sandy River Basin, Blaine Creek, Kentucky. Foundation Report. Construction of Dam and Appurtenant Works, Phase 2. Volume 1

DTIC Science & Technology

1990-09-01

and grouting were performed from the rock surface using expandable-air packers . Grouting was performed by injecting, into a hole, a neat grout ( cement ...Water & cement type I & II Mix: ........................... 6:1 to 0.75:1 Connection: .................... Air packer , close to surface...pressure tested then backfilled. The holes were hydraulic-pressure tested with a single air- expanding packer near the surface at 5 psi gauge pressure. If

An Experimental Investigation into Failure and Localization Phenomena in the Extension to Shear Fracture Transition in Rock

NASA Astrophysics Data System (ADS)

Choens, R. C., II; Chester, F. M.; Bauer, S. J.; Flint, G. M.

2014-12-01

Fluid-pressure assisted fracturing can produce mesh and other large, interconnected and complex networks consisting of both extension and shear fractures in various metamorphic, magmatic and tectonic systems. Presently, rock failure criteria for tensile and low-mean compressive stress conditions is poorly defined, although there is accumulating evidence that the transition from extension to shear fracture with increasing mean stress is continuous. We report on the results of experiments designed to document failure criteria, fracture mode, and localization phenomena for several rock types (sandstone, limestone, chalk and marble). Experiments were conducted in triaxial extension using a necked (dogbone) geometry to achieve mixed tension and compression stress states with local component-strain measurements in the failure region. The failure envelope for all rock types is similar, but are poorly described using Griffith or modified Griffith (Coulomb or other) failure criteria. Notably, the mode of fracture changes systematically from pure extension to shear with increase in compressive mean stress and display a continuous change in fracture orientation with respect to principal stress axes. Differential stress and inelastic strain show a systematic increase with increasing mean stress, whereas the axial stress decreases before increasing with increasing mean stress. The stress and strain data are used to analyze elastic and plastic strains leading to failure and compare the experimental results to predictions for localization using constitutive models incorporating on bifurcation theory. Although models are able to describe the stability behavior and onset of localization qualitatively, the models are unable to predict fracture type or orientation. Constitutive models using single or multiple yield surfaces are unable to predict the experimental results, reflecting the difficulty in capturing the changing micromechanisms from extension to shear failure. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Deopartment of Energy's National Security Administration under contract DE-AC04-94AL85000. SAND2014-16578A

Quantitative Relationships Linking Rock Strength to Channel Morphology: A Case Study in Central Arizona

NASA Astrophysics Data System (ADS)

Larimer, J. E.; Yanites, B.

2016-12-01

River morphology is a consequence of the erosive forces acting on the channel boundary and the resisting forces that limit erosion. For bedrock rivers, the erosive forces are generated by the stresses exerted by impacting sediment and flowing water, while the resisting forces are controlled by the internal strength regime of the local rock. We investigate the susceptibility of different rock types to different erosional processes (i.e. abrasion and plucking) and how changes in channel morphology reflect rock strength properties across lithologic boundaries. The bedrock rivers in the Prescott National Forest, AZ flow over a number of rock types with variable strength including sedimentary, igneous, and metamorphic lithologies providing a natural experiment to quantify the influence of rock strength on channel morphology. We collected bedrock samples and channel surveys from 12 different rock types. Rock-strength and rock-mass properties include compressive strength, tensile strength, fatigue strength, decimeter scale P-wave velocity (varies by 8-fold), Schmidt rebound value, fracture spacing, fracture aperture, and slake durability (as a proxy for weathering susceptibility. Morphological measurements include channel width, channel steepness (varies by 10-fold), and grain size distribution. To distinguish between the major mechanisms of erosion we measure bedrock surface roughness factor at the centimeter scale. Preliminary results show that channel steepness (ksn) increases with P-wave velocity while normalized channel width (kwn) decreases with P-wave velocity. We use these data to quantify scaling relationships of channel geometry with rock strength properties. We consider the results in the context of the driving mechanistic process to develop new quantitative understandings of how rock strength properties influence the efficiency of erosion processes and how rock strength is reflected in river morphology. By comparing the results among different rock types in a landscape subject to spatially consistent tectonic and climatic influence, our work seeks to advance process-based river erosion models through field and laboratory measurements.

Mapping of rock types using a joint approach by combining the multivariate statistics, self-organizing map and Bayesian neural networks: an example from IODP 323 site

NASA Astrophysics Data System (ADS)

Karmakar, Mampi; Maiti, Saumen; Singh, Amrita; Ojha, Maheswar; Maity, Bhabani Sankar

2017-07-01

Modeling and classification of the subsurface lithology is very important to understand the evolution of the earth system. However, precise classification and mapping of lithology using a single framework are difficult due to the complexity and the nonlinearity of the problem driven by limited core sample information. Here, we implement a joint approach by combining the unsupervised and the supervised methods in a single framework for better classification and mapping of rock types. In the unsupervised method, we use the principal component analysis (PCA), K-means cluster analysis (K-means), dendrogram analysis, Fuzzy C-means (FCM) cluster analysis and self-organizing map (SOM). In the supervised method, we use the Bayesian neural networks (BNN) optimized by the Hybrid Monte Carlo (HMC) (BNN-HMC) and the scaled conjugate gradient (SCG) (BNN-SCG) techniques. We use P-wave velocity, density, neutron porosity, resistivity and gamma ray logs of the well U1343E of the Integrated Ocean Drilling Program (IODP) Expedition 323 in the Bering Sea slope region. While the SOM algorithm allows us to visualize the clustering results in spatial domain, the combined classification schemes (supervised and unsupervised) uncover the different patterns of lithology such of as clayey-silt, diatom-silt and silty-clay from an un-cored section of the drilled hole. In addition, the BNN approach is capable of estimating uncertainty in the predictive modeling of three types of rocks over the entire lithology section at site U1343. Alternate succession of clayey-silt, diatom-silt and silty-clay may be representative of crustal inhomogeneity in general and thus could be a basis for detail study related to the productivity of methane gas in the oceans worldwide. Moreover, at the 530 m depth down below seafloor (DSF), the transition from Pliocene to Pleistocene could be linked to lithological alternation between the clayey-silt and the diatom-silt. The present results could provide the basis for the detailed study to get deeper insight into the Bering Sea' sediment deposition and sequence.

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.

Solute transport in crystalline rocks at Aspö--I: geological basis and model calibration.

PubMed

Mazurek, Martin; Jakob, Andreas; Bossart, Paul

2003-03-01

Water-conducting faults and fractures were studied in the granite-hosted Aspö Hard Rock Laboratory (SE Sweden). On a scale of decametres and larger, steeply dipping faults dominate and contain a variety of different fault rocks (mylonites, cataclasites, fault gouges). On a smaller scale, somewhat less regular fracture patterns were found. Conceptual models of the fault and fracture geometries and of the properties of rock types adjacent to fractures were derived and used as input for the modelling of in situ dipole tracer tests that were conducted in the framework of the Tracer Retention Understanding Experiment (TRUE-1) on a scale of metres. After the identification of all relevant transport and retardation processes, blind predictions of the breakthroughs of conservative to moderately sorbing tracers were calculated and then compared with the experimental data. This paper provides the geological basis and model calibration, while the predictive and inverse modelling work is the topic of the companion paper [J. Contam. Hydrol. 61 (2003) 175]. The TRUE-1 experimental volume is highly fractured and contains the same types of fault rocks and alterations as on the decametric scale. The experimental flow field was modelled on the basis of a 2D-streamtube formalism with an underlying homogeneous and isotropic transmissivity field. Tracer transport was modelled using the dual porosity medium approach, which is linked to the flow model by the flow porosity. Given the substantial pumping rates in the extraction borehole, the transport domain has a maximum width of a few centimetres only. It is concluded that both the uncertainty with regard to the length of individual fractures and the detailed geometry of the network along the flowpath between injection and extraction boreholes are not critical because flow is largely one-dimensional, whether through a single fracture or a network. Process identification and model calibration were based on a single uranine breakthrough (test PDT3), which clearly showed that matrix diffusion had to be included in the model even over the short experimental time scales, evidenced by a characteristic shape of the trailing edge of the breakthrough curve. Using the geological information and therefore considering limited matrix diffusion into a thin fault gouge horizon resulted in a good fit to the experiment. On the other hand, fresh granite was found not to interact noticeably with the tracers over the time scales of the experiments. While fracture-filling gouge materials are very efficient in retarding tracers over short periods of time (hours-days), their volume is very small and, with time progressing, retardation will be dominated by altered wall rock and, finally, by fresh granite. In such rocks, both porosity (and therefore the effective diffusion coefficient) and sorption K(d)s are more than one order of magnitude smaller compared to fault gouge, thus indicating that long-term retardation is expected to occur but to be less pronounced. Copyright 2002 Elsevier Science B.V.

Classification and Distribution of Mars Pathfinder Rocks Using Quantitative Morphologic Indices

NASA Technical Reports Server (NTRS)

Yingst, R. A.; Biederman, K. L.; Monhead, A. M.; Haldemann, A. F. C.; Kowalczyk, M. R.

2004-01-01

The Mars Pathfinder (MPF) landing site was predicted to contain a broad sampling of rock types varying in mineralogical, physical, mechanical and geochemical characteristics. Although rocks have been divided into several spectral categories based on Imager for Mars Pathfinder visible/near-infrared spectra, it has not been fully determined which of these stem from intrinsic mineralogical differences between rocks or rock surfaces, and which result from factors such as physical or chemical weathering. This has made isolation of unique mineralogy's difficult. Efforts in isolating and classifying spectral units among MPF rocks and soils have met with varying degrees of success, and the current understanding is such that many factors influencing spectral signatures cannot be quantified to a sufficient level so they may be removed. The result is that fundamental questions regarding information needed to reveal the present and past interactions between the rocks and rock surfaces and the Martian environment remain unanswered. But it is possible to approach the issue of identifying distinct rock and rock surface types from a different angle.

Effect of Hydrothermal Alteration on Rock Properties in Active Geothermal Setting

NASA Astrophysics Data System (ADS)

Mikisek, P.; Bignall, G.; Sepulveda, F.; Sass, I.

2012-04-01

Hydrothermal alteration records the physical-chemical changes of rock and mineral phases caused by the interaction of hot fluids and wall rock, which can impact effective permeability, porosity, thermal parameters, rock strength and other rock properties. In this project, an experimental approach has been used to investigate the effects of hydrothermal alteration on rock properties. A rock property database of contrastingly altered rock types and intensities has been established. The database details horizontal and vertical permeability, porosity, density, thermal conductivity and thermal heat capacity for ~300 drill core samples from wells THM12, THM13, THM14, THM17, THM18, THM22 and TH18 in the Wairakei-Tauhara geothermal system (New Zealand), which has been compared with observed hydrothermal alteration type, rank and intensity obtained from XRD analysis and optical microscopy. Samples were selected from clay-altered tuff and intercalated siltstones of the Huka Falls Formation, which acts as a cap rock at Wairakei-Tauhara, and tuffaceous sandstones of the Waiora Formation, which is a primary reservoir-hosting unit for lateral and vertical fluid flows in the geothermal system. The Huka Falls Formation exhibits argillic-type alteration of varying intensity, while underlying Waiora Formations exhibits argillic- and propylithic-type alteration. We plan to use a tempered triaxial test cell at hydrothermal temperatures (up to 200°C) and pressures typical of geothermal conditions, to simulate hot (thermal) fluid percolation through the rock matrix of an inferred "reservoir". Compressibility data will be obtained under a range of operating (simulation reservoir) conditions, in a series of multiple week to month-long experiments that will monitor change in permeability and rock strength accompanying advancing hydrothermal alteration intensity caused by the hot brine interacting with the rock matrix. We suggest, our work will provide new baseline information concerning fluid-rock interaction processes in geothermal reservoirs, and their effects on rock properties, that will aid improved understanding of the evolution of high-temperature geothermal systems, provide constraints to parameterization of reservoir models and assist future well planning and design through prediction of rock properties in the context of drilling strategies.

Extrapolation of bulk rock elastic moduli of different rock types to high pressure conditions and comparison with texture-derived elastic moduli

NASA Astrophysics Data System (ADS)

Ullemeyer, Klaus; Lokajíček, Tomás; Vasin, Roman N.; Keppler, Ruth; Behrmann, Jan H.

2018-02-01

In this study elastic moduli of three different rock types of simple (calcite marble) and more complex (amphibolite, micaschist) mineralogical compositions were determined by modeling of elastic moduli using texture (crystallographic preferred orientation; CPO) data, experimental investigation and extrapolation. 3D models were calculated using single crystal elastic moduli, and CPO measured using time-of-flight neutron diffraction at the SKAT diffractometer in Dubna (Russia) and subsequently analyzed using Rietveld Texture Analysis. To define extrinsic factors influencing elastic behaviour, P-wave and S-wave velocity anisotropies were experimentally determined at 200, 400 and 600 MPa confining pressure. Functions describing variations of the elastic moduli with confining pressure were then used to predict elastic properties at 1000 MPa, revealing anisotropies in a supposedly crack-free medium. In the calcite marble elastic anisotropy is dominated by the CPO. Velocities continuously increase, while anisotropies decrease from measured, over extrapolated to CPO derived data. Differences in velocity patterns with sample orientation suggest that the foliation forms an important mechanical anisotropy. The amphibolite sample shows similar magnitudes of extrapolated and CPO derived velocities, however the pattern of CPO derived velocity is closer to that measured at 200 MPa. Anisotropy decreases from the extrapolated to the CPO derived data. In the micaschist, velocities are higher and anisotropies are lower in the extrapolated data, in comparison to the data from measurements at lower pressures. Generally our results show that predictions for the elastic behavior of rocks at great depths are possible based on experimental data and those computed from CPO. The elastic properties of the lower crust can, thus, be characterized with an improved degree of confidence using extrapolations. Anisotropically distributed spherical micro-pores are likely to be preserved, affecting seismic velocity distributions. Compositional variations in the polyphase rock samples do not significantly change the velocity patterns, allowing the use of RTA-derived volume percentages for the modeling of elastic moduli.

Mercury contamination in agricultural soils from abandoned metal mines classified by geology and mineralization.

PubMed

Kim, Han Sik; Jung, Myung Chae

2012-01-01

This survey aimed to compare mercury concentrations in soils related to geology and mineralization types of mines. A total of 16,386 surface soils (0~15 cm in depth) were taken from agricultural lands near 343 abandoned mines (within 2 km from each mine) and analyzed for Hg by AAS with a hydride-generation device. To meaningfully compare mercury levels in soils with geology and mineralization types, three subclassification criteria were adapted: (1) five mineralization types, (2) four valuable ore mineral types, and (3) four parent rock types. The average concentration of Hg in all soils was 0.204 mg kg(-1) with a range of 0.002-24.07 mg kg(-1). Based on the mineralization types, average Hg concentrations (mg kg(-1)) in the soils decreased in the order of pegmatite (0.250) > hydrothermal vein (0.208) > hydrothermal replacement (0.166) > skarn (0.121) > sedimentary deposits (0.045). In terms of the valuable ore mineral types, the concentrations decreased in the order of Au-Ag-base metal mines ≈ base metal mines > Au-Ag mines > Sn-W-Mo-Fe-Mn mines. For parent rock types, similar concentrations were found in the soils derived from sedimentary rocks and metamorphic rocks followed by heterogeneous rocks with igneous and metamorphic processes. Furthermore, farmland soils contained relatively higher Hg levels than paddy soils. Therefore, it can be concluded that soils in Au, Ag, and base metal mines derived from a hydrothermal vein type of metamorphic rocks and pegmatite deposits contained relatively higher concentrations of mercury in the surface environment.

Utilization of advanced calibration techniques in stochastic rock fall analysis of quarry slopes

NASA Astrophysics Data System (ADS)

Preh, Alexander; Ahmadabadi, Morteza; Kolenprat, Bernd

2016-04-01

In order to study rock fall dynamics, a research project was conducted by the Vienna University of Technology and the Austrian Central Labour Inspectorate (Federal Ministry of Labour, Social Affairs and Consumer Protection). A part of this project included 277 full-scale drop tests at three different quarries in Austria and recording key parameters of the rock fall trajectories. The tests involved a total of 277 boulders ranging from 0.18 to 1.8 m in diameter and from 0.009 to 8.1 Mg in mass. The geology of these sites included strong rock belonging to igneous, metamorphic and volcanic types. In this paper the results of the tests are used for calibration and validation a new stochastic computer model. It is demonstrated that the error of the model (i.e. the difference between observed and simulated results) has a lognormal distribution. Selecting two parameters, advanced calibration techniques including Markov Chain Monte Carlo Technique, Maximum Likelihood and Root Mean Square Error (RMSE) are utilized to minimize the error. Validation of the model based on the cross validation technique reveals that in general, reasonable stochastic approximations of the rock fall trajectories are obtained in all dimensions, including runout, bounce heights and velocities. The approximations are compared to the measured data in terms of median, 95% and maximum values. The results of the comparisons indicate that approximate first-order predictions, using a single set of input parameters, are possible and can be used to aid practical hazard and risk assessment.

Dual origins for pantellerites, and other puzzles, at Mount Takahe volcano, Marie Byrd Land, West Antarctica

NASA Astrophysics Data System (ADS)

LeMasurier, Wesley; Choi, Sung Hi; Kawachi, Yosuke; Mukasa, Sam; Rogers, Nick

2018-01-01

Mt. Takahe is a large, late Quaternary trachyte shield volcano that rises through 2000 + m of the West Antarctic ice sheet. It is composed mostly of ne-trachyte, hy-ol-trachyte, and qz-trachyte flows, with subordinate basanite, intermediate rocks, and pantellerites. All rock types can be adequately modeled by fractional crystallization of basanite - the only basaltic rock exposed here. The ne-trachytes can be explained by a single stage of low-pressure fractionation near the base of the upper crust. Models of oversaturated rocks require a period of evolution at a depth of 35 km, below the stability field of plagioclase, where fractionation of kaersutite and associated high pressure minerals will yield silica oversaturated residual magmas. This is then followed by a period of fractionation at a depth of 3 km, where peralkalinity and Fe-enrichment are acquired. Pantellerite compositions span virtually the entire spectrum of peralkalinity, Fe-enrichment, LILE-enrichment, and SiO2 values, and seem to represent a range of residence times in upper crustal vs., upper mantle magma chambers. Mt. Takahe is unusual among Marie Byrd Land volcanoes for its geochemical anomalies. These include the lowest 143Nd/144Nd ratios in West Antarctica, and unusually high but unpredictable Ba values. These anomalies are believed to originate in a pre-85 Ma subduction mélange at the base of the lithosphere, which seems to be the source of Mt. Takahe basaltic rocks.

Zircon U-Pb, O, and Hf isotopic constraints on Mesozoic magmatism in the Cyclades, Aegean Sea, Greece

NASA Astrophysics Data System (ADS)

Fu, Bin; Bröcker, Michael; Ireland, Trevor; Holden, Peter; Kinsley, Leslie P. J.

2015-01-01

Compared to the well-documented Cenozoic magmatic and metamorphic rocks of the Cyclades, Aegean Sea, Greece, the geodynamic context of older meta-igneous rocks occurring in the marble-schist sequences and mélanges of the Cycladic Blueschist Unit is as yet not fully understood. Here, we report O-Hf isotopic compositions of zircons ranging in age from ca. 320 Ma to ca. 80 Ma from metamorphic rocks exposed on the islands of Andros, Ios, Sifnos, and Syros with special emphasis on Triassic source rocks. Ion microprobe (SHRIMP II) single spot oxygen isotope analysis of pre-Cretaceous zircons from various felsic gneisses and meta-gabbros representing both the marble-schist sequences and the mélanges of the study area yielded a large range in δ18O values, varying from 2.7 ‰ to 10.1 ‰ VSMOW, with one outlier at -0.4 %. Initial ɛHf values (-12.5 to +15.7) suggest diverse sources for melts formed between Late Carboniferous to Late Cretaceous time that record derivation from mantle and reworked older continental crust. In particular, variable δ18O and ɛHf( t) values for Triassic igneous zircons suggest that magmatism of this age is more likely rift- than subduction-related. The significant crustal component in 160 Ma meta-gabbros from Andros implies that some Jurassic gabbroic rocks of the Hellenides are not part of SSZ-type (supra-subduction zone) ophiolites that are common elsewhere along the margin of the Pelagonian zone.

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).

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.

Tales from the tomb: the microbial ecology of exposed rock surfaces.

PubMed

Brewer, Tess E; Fierer, Noah

2018-03-01

Although a broad diversity of eukaryotic and bacterial taxa reside on rock surfaces where they can influence the weathering of rocks and minerals, these communities and their contributions to mineral weathering remain poorly resolved. To build a more comprehensive understanding of the diversity, ecology and potential functional attributes of microbial communities living on rock, we sampled 149 tombstones across three continents and analysed their bacterial and eukaryotic communities via marker gene and shotgun metagenomic sequencing. We found that geographic location and climate were important factors structuring the composition of these communities. Moreover, the tombstone-associated microbial communities varied as a function of rock type, with granite and limestone tombstones from the same cemeteries harbouring taxonomically distinct microbial communities. The granite and limestone-associated communities also had distinct functional attributes, with granite-associated bacteria having more genes linked to acid tolerance and chemotaxis, while bacteria on limestone were more likely to be lichen associated and have genes involved in photosynthesis and radiation resistance. Together these results indicate that rock-dwelling microbes exhibit adaptations to survive the stresses of the rock surface, differ based on location, climate and rock type, and seem pre-disposed to different ecological strategies (symbiotic versus free-living lifestyles) depending on the rock type. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

How do subcritical cracking rates and styles influence rock erosion? A test case from the Blue Ridge Mountains of Virginia.

NASA Astrophysics Data System (ADS)

Eppes, M. C.; Hancock, G. S.; Dewers, T. A.; Chen, X.; Eichhubl, P.

2017-12-01

There is a disconnect between measured rates of rock erosion and regolith production and our understanding of the factors and processes that drive them. Here we examine the mechanical weathering (cracking) characteristics of natural, bare bedrock outcrops characterized by 10Be derived erosion rates that vary from 2 to 40 m/my in the Blue Ridge Mountains, VA. Observed erosion rate variance generally correlates with rock type; we seek to characterize and quantify to what extent the mechanical weathering properties of the different rock types drive erosion rates. We assert that subcritical cracking constitutes the primary mechanism by which the outcrops increase their porosity and subsequently weather and erode. We therefore hypothesize that rock parameters that control rates and styles of subcritical cracking set the outcrop erosion rates. For each outcrop, we measured crack characteristics along transects: for every crack >2 cm length, we measured its length, width, orientation, and weathering characteristics (rounded vs sharp edges); and we measured the thickness of all `steps' (spallation remnants) encountered in the transects. For most outcrops, we collected surface samples in order to characterize their mineralogy and microcracking characteristics through thin section analysis. For each rock type, we collected samples for which we measured fracture toughness, as well as the subcritical crack growth index under different moisture conditions. Preliminary analysis of the field crack data indicates that each rock type (granite, sandstone, quartzite) is characterized by unique macro- and micro-scale crack characteristics consistent with known generic subcritical cracking parameters for those rocks. Crack density and length correlate with erosion rates in faster eroding rock types, but not slowly eroding ones. Overall, we hope these data will help to shed light on the driving and limiting factors for the mechanical production of porosity in rock at and near Earth's surface.

Petrography and petrology of Smoky Butte intrusives, Garfield County, Montana

USGS Publications Warehouse

Matson, Robert E.

1960-01-01

The Smoky Butte intrusives are located in T. 18 N., R. 36 E. Garfield County, Montana on the extreme eastern edge of the petrographic province of Central Montana. They consist of dikes and plugs arranged in linear, en-echelon pattern with a northeast trend and intrude the Tullock member (Paleocene age) of the Fort Union formation. Extrusive rocks are absent. The rocks are potassium-rich volcanic types showing a disequilibrium mineral assemblage consisting of sanidine, leucite, biotite, olivine, pyroxene, magnetite plus. ilmenite, apatite, calcite, quartz, and a yellowish to dark greenish glassy groundmass. Two chemical analyses of Smoky Butte rocks show high magnesium, potassium, titanium, and phosphorous and low aluminum and sodium content. The two norm calculations show that the rocks are oversaturated with 1.3 and 3.1 per-cent excess silica. Because of the peculiar nature of the Smoky Butte rocks, descriptive names have been applied to them. They are divided into six different types. Three periods of intrusion are proposed for Smoky Butte quarry where three rock types crop out. Other evidence for multiple injection occurs in several multiple dikes. The upper contact of the intrusion is visible on a few plugs and dikes. Smoky Butte rocks show some similarities to the undersaturated potassium-rich rocks of the Highwood and Bearpaw Mountains of Montana, the rocks of the Leucite Hills of Wyoming, and the oversaturated rocks of the West Kimberly District of Australia.

Electrochemical behavior of Alloy 22 and friction type rock bolt

NASA Astrophysics Data System (ADS)

Rahman, Md Sazzadur

Alloy 22 (Ni-22Cr-13Mo-3Fe-3W) is a candidate alloy for the outer shell of spent nuclear materials storage containers in the Yucca Mountain High Level Nuclear Waste Repository because of its excellent corrosion resistance. The nuclear waste container is cylindrical in shape and the end caps are welded. Typically, Alloy 22 retains the high temperature single phase cubic structure near room temperature, but topologically close packed (TCP) phases such as mu, P, sigma etc. and Cr rich carbides can form during thermal aging and welding. Rock bolts that are used for reinforcing subsurface tunnels are generally made of carbon or low alloy steels; these are being used in the nuclear repository tunnel. The corrosion behavior of these rock bolts have not been systematically evaluated under the environmental conditions of the repository. The ground waters at the Yucca Mountain (YM) repository permeate through the pores of the rock mass, and have propensity to corrode the rock bolts and waste package container. The environmental (aerated and deaerated) conditions influence the rate of corrosion in these material; these have not been systematically evaluated yet under the repository environment. In this study, the corrosion behavior of Alloy 22 and a friction type rock bolts was investigated as a function of temperature and concentration in complex multi-ionic electrolytes. Simulated electrolyte of YM ground water found in the repository environment was made in different concentrations (1X, 10X, and 100X). The interaction of simulated electrolytes in aerated and deaerated condition with Alloy 22 and low alloy steel of friction type rock bolt (split tapered cylinder type commercial design) has been investigated. Polarization resistance method was used to measure the corrosion rates. We found that the corrosion rate of Alloy 22 was higher in the deaerated electrolyte as compared to the aerated. The presence of oxygen in the electrolyte during aeration is conducive to formation of passive films that inhibits the corrosion process. The temperature dependency of the corrosion rate was affected by aeration and deaeration of the electrolytes. Another study related to corrosion behavior of weld Alloy 22 was undertaken to understand electrochemical behavior of welded structures. Corrosion studies were carried out in more aggressive electrolyte (0.1M HCl at 66°C) after solution annealing at 1121°C for 1 hr. In the as-welded structure a dendritic microstructure was observed in the weld region. However, after solution annealing these dendrites are not observed; suggesting homogenization of the grains. Three different specimens were made out from a welded Alloy 22 plates with large welded surface; weld interface, half weld and base metal away from the weld and heat affected zone, and corrosion rates of all these samples were measured. The results showed that the corrosion resistance of the solution annealed was higher in all three specimens than those of as-welded specimens. Corrosion rates of friction type set rock bolts (split set) were measured at 25°C, 45°C, 65°C and 90°C using 1X, 10X and 100X concentration of electrolyte both in aerated and deaerated conditions. The corrosion rates of rock bolts in 1X and 10X electrolyte showed ranged from ˜30 to 200mum/yr for deaerated and 150 to 1600 mum/yr for aerated. In summary, we have investigated the electrochemical behavior of the Alloy 22 and steels that have significance to the YM nuclear repository. The effects of temperature, type of electrolyte, condition of the alloys on the corrosion rates are reported.

Modeling rock specimens through 3D printing: Tentative experiments and prospects

NASA Astrophysics Data System (ADS)

Jiang, Quan; Feng, Xiating; Song, Lvbo; Gong, Yahua; Zheng, Hong; Cui, Jie

2016-02-01

Current developments in 3D printing (3DP) technology provide the opportunity to produce rock-like specimens and geotechnical models through additive manufacturing, that is, from a file viewed with a computer to a real object. This study investigated the serviceability of 3DP products as substitutes for rock specimens and rock-type materials in experimental analysis of deformation and failure in the laboratory. These experiments were performed on two types of materials as follows: (1) compressive experiments on printed sand-powder specimens in different shapes and structures, including intact cylinders, cylinders with small holes, and cuboids with pre-existing cracks, and (2) compressive and shearing experiments on printed polylactic acid cylinders and molded shearing blocks. These tentative tests for 3DP technology have exposed its advantages in producing complicated specimens with special external forms and internal structures, the mechanical similarity of its product to rock-type material in terms of deformation and failure, and its precision in mapping shapes from the original body to the trial sample (such as a natural rock joint). These experiments and analyses also successfully demonstrate the potential and prospects of 3DP technology to assist in the deformation and failure analysis of rock-type materials, as well as in the simulation of similar material modeling experiments.

Environmental Assessment. Proposed Sahara Mustard Control on the Barry M. Goldwater Range - East

DTIC Science & Technology

2012-02-01

While some sites consist of only a few artifacts or a single archaeological feature such as a trail or a hearth ; others cover a large area and...such as hearths , roasting pits, and fire-affected rock, cleared areas or sleeping circles, linear and circular rock alignments, rock cairns, trails

Chemical weathering indices applied to weathering profiles developed on heterogeneous felsic metamorphic parent rocks

Treesearch

Jason R. Price; Michael A. Velbel

2003-01-01

Chemical weathering indices are commonly used for characterizing weathering profiles by incorporating bulk major element oxide chemistry into a single metric for each sample. Generally, on homogeneous parent rocks, weathering indices change systematically with depth. However, the weathering of heterogeneous metamorphic rocks confounds the relationship between...

Rheological stratification of the Hormuz Salt Formation in Iran - microstructural study of the dirty and pure rock salts from the Kuh-e-Namak (Dashti) salt diapir

NASA Astrophysics Data System (ADS)

Závada, Prokop; Desbois, Guillaume; Urai, Janos; Schulmann, Karel; Rahmati, Mahmoud; Lexa, Ondrej; Wollenberg, Uwe

2014-05-01

Significant viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' terrestrial debris bearing rock salt types and 'strong' pure rock salt types are questioned for deformation mechanisms using detailed quantitative microstructural study including crystallographic preferred orientation (CPO) mapping of halite grains. While the solid impurity rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts (debris free) reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although flow in both, the recrystallized dirty and clean salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS) and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts are explained by significantly slower rates of intergranular diffusion and piling up of dislocations at hematite inclusions in clean salt types. Porphyroclasts of clean salts deform by semi-brittle and plastic mechanisms with intra-crystalline damage being induced also by fluid inclusions that explode in the crystals at high fluid pressures. Boudins of clean salt types with coarse grained and original sedimentary microstructure suggest that clean rock salts are associated with dislocation creep dominated power law flow in the source layer and the diapiric stem. Rheological contrasts between both rock salt classes apply in general for the variegated and terrestrial debris rich ("dirty") Lower Hormuz and the "clean" rock salt forming the Upper Hormuz, respectively, and suggest that large strain rate gradients likely exist along horizons of mobilized salt types of different composition and microstructure.

The vernon supersuite: Mesoproterozoic A-type granitoid rocks in the New Jersey highlands

USGS Publications Warehouse

Volkert, R.A.; Drake, Avery A.

1998-01-01

Abundant Mesoproterozoic A-type granitoid rocks of two intrusive suites underlie approximately 50 percent of the New Jersey Highlands. These rocks, the Byram Intrusive and Lake Hopatcong Intrusive Suites, consist of granite, alaskite, quartz monzonite, monzonite, and minor pegmatite. Byram and Lake Hopatcong rocks, although different mineralogically, are similar geochemically and contain overlapping abundances of most major and trace elements. Petrographic relationships, geochronology, field relationships, and geochemical similarities support a comagmatic origin for both suites. They constitute the here named Vernon Supersuite.

General Approach for Rock Classification Based on Digital Image Analysis of Electrical Borehole Wall Images

NASA Astrophysics Data System (ADS)

Linek, M.; Jungmann, M.; Berlage, T.; Clauser, C.

2005-12-01

Within the Ocean Drilling Program (ODP), image logging tools have been routinely deployed such as the Formation MicroScanner (FMS) or the Resistivity-At-Bit (RAB) tools. Both logging methods are based on resistivity measurements at the borehole wall and therefore are sensitive to conductivity contrasts, which are mapped in color scale images. These images are commonly used to study the structure of the sedimentary rocks and the oceanic crust (petrologic fabric, fractures, veins, etc.). So far, mapping of lithology from electrical images is purely based on visual inspection and subjective interpretation. We apply digital image analysis on electrical borehole wall images in order to develop a method, which augments objective rock identification. We focus on supervised textural pattern recognition which studies the spatial gray level distribution with respect to certain rock types. FMS image intervals of rock classes known from core data are taken in order to train textural characteristics for each class. A so-called gray level co-occurrence matrix is computed by counting the occurrence of a pair of gray levels that are a certain distant apart. Once the matrix for an image interval is computed, we calculate the image contrast, homogeneity, energy, and entropy. We assign characteristic textural features to different rock types by reducing the image information into a small set of descriptive features. Once a discriminating set of texture features for each rock type is found, we are able to discriminate the entire FMS images regarding the trained rock type classification. A rock classification based on texture features enables quantitative lithology mapping and is characterized by a high repeatability, in contrast to a purely visual subjective image interpretation. We show examples for the rock classification between breccias, pillows, massive units, and horizontally bedded tuffs based on ODP image data.

Rocks and geology in the San Francisco Bay region

USGS Publications Warehouse

Stoffer, Philip W.

2002-01-01

The landscape of the San Francisco Bay region is host to a greater variety of rocks than most other regions in the United States. This introductory guide provides illustrated descriptions of 46 common and important varieties of igneous, sedimentary, and metamorphic rock found in the region. Rock types are described in context of their identification qualities, how they form, and where they occur in the region. The guide also provides discussion about of regional geology, plate tectonics, the rock cycle, the significance of the selected rock types in relation to both earth history and the impact of mineral resources on the development in the region. Maps and text also provide information where rocks, fossils, and geologic features can be visited on public lands or in association with public displays in regional museums, park visitor centers, and other public facilities.

Integrated database for rapid mass movements in Norway

NASA Astrophysics Data System (ADS)

Jaedicke, C.; Lied, K.; Kronholm, K.

2009-03-01

Rapid gravitational slope mass movements include all kinds of short term relocation of geological material, snow or ice. Traditionally, information about such events is collected separately in different databases covering selected geographical regions and types of movement. In Norway the terrain is susceptible to all types of rapid gravitational slope mass movements ranging from single rocks hitting roads and houses to large snow avalanches and rock slides where entire mountainsides collapse into fjords creating flood waves and endangering large areas. In addition, quick clay slides occur in desalinated marine sediments in South Eastern and Mid Norway. For the authorities and inhabitants of endangered areas, the type of threat is of minor importance and mitigation measures have to consider several types of rapid mass movements simultaneously. An integrated national database for all types of rapid mass movements built around individual events has been established. Only three data entries are mandatory: time, location and type of movement. The remaining optional parameters enable recording of detailed information about the terrain, materials involved and damages caused. Pictures, movies and other documentation can be uploaded into the database. A web-based graphical user interface has been developed allowing new events to be entered, as well as editing and querying for all events. An integration of the database into a GIS system is currently under development. Datasets from various national sources like the road authorities and the Geological Survey of Norway were imported into the database. Today, the database contains 33 000 rapid mass movement events from the last five hundred years covering the entire country. A first analysis of the data shows that the most frequent type of recorded rapid mass movement is rock slides and snow avalanches followed by debris slides in third place. Most events are recorded in the steep fjord terrain of the Norwegian west coast, but major events are recorded all over the country. Snow avalanches account for most fatalities, while large rock slides causing flood waves and huge quick clay slides are the most damaging individual events in terms of damage to infrastructure and property and for causing multiple fatalities. The quality of the data is strongly influenced by the personal engagement of local observers and varying observation routines. This database is a unique source for statistical analysis including, risk analysis and the relation between rapid mass movements and climate. The database of rapid mass movement events will also facilitate validation of national hazard and risk maps.

Chemical, mineralogical and textural systematics of non-mare melt rocks: Implications for lunar impact and volcanic processes

NASA Technical Reports Server (NTRS)

Irving, A. J.

1975-01-01

Based on a synthesis of chemical data for over 200 samples, the nonmare rocks with fine grained melt textures can be classified into 7 major groups: anorthositic basalts, troctolitic basalts, VHA basalts, Apollo 14-type KREEP basalts, Apollo 15-type KREEP basalts, Apollo 17-type KREEP basalts, and aluminous mare basalts. Review of chemical, mineralogical, textural and experimental evidence leads to preferred hypotheses for the origins of these rocks; those hypotheses are discussed in detail.

A review of silver-rich mineral deposits and their metallogeny

USGS Publications Warehouse

Graybeal, Frederick T.; Vikre, Peter

2010-01-01

Mineral deposits with large inventories or high grades of silver are found in four genetic groups: (1) volcanogenic massive sulfide (VMS), (2) sedimentary exhalative (SEDEX), (3) lithogene, and, (4) magmatichydrothermal. Principal differences between the four groups relate to source rocks and regions, metal associations, process and timing of mineralization, and tectonic setting. These four groups may be subdivided into specific metal associations on ternary diagrams based on relative metal contents. The VMS deposits rarely contain more than 15,600 t Ag (500 Moz). Grades average 33 g/t Ag. Variable Ag- Pb-Zn-Cu-Au ± Sn concentrations are interpreted as having been derived both from shallow plutons and by leaching of the volcanic rock pile in regions of thin or no continental crust and the mineralization is syngenetic. Higher silver grades are associated with areas of abundant felsic volcanic rocks. The SEDEX deposits rarely contain more than 15,600 t Ag (500 Moz). Grades average 46 g/t Ag. Silver, lead, and zinc in relatively consistent proportions are leached from sedimentary rocks filling rift-related basins, where the continental crust is thin, and deposited as syngenetic to diagenetic massive sulfides. Pre-mineral volcanic rocks and their detritus may occur deep within the basin and gold is typically absent. Lithogene silver-rich deposits are epigenetic products of varying combinations of compaction, dewatering, meteoric water recharge, and metamorphism of rift basin-related clastic sedimentary and interbedded volcanic rocks. Individual deposits may contain more than 15,600 t Ag (500 Moz) at high grades. Ores are characterized by four well-defined metal associations, including Ag, Ag-Pb-Zn, Ag-Cu, and Ag-Co-Ni-U. Leaching, transport, and deposition of metals may occur both in specific sedimentary strata and other rock types adjacent to the rift. Multiple mineralizing events lasting 10 to 15 m.y., separated by as much as 1 b.y., may occur in a single basin. Gold is absent at economic levels. The magmatic-hydrothermal silver-rich deposits are epigenetic and related to cordilleran igneous and volcanic suites. Six magmatic-hydrothermal districts each contain more than 31,000 t Ag (1,000 Moz) with grades of veins >600 g/t Ag. Mineralization occurs as veins, massive sulfides in carbonate rocks, and disseminated deposits including porphyry silver deposits, a proposed exploration model. Most deposits are epithermal with low-sulfidation alteration assemblages. Deposits are often telescoped and well-zoned. All large and high-grade magmatic-hydrothermal deposits appear confined to regions of relatively thick continental crust above Cenozoic consuming plate margins on the eastern side of the Pacific Rim. Silver in these deposits may be partly derived by hydrothermal leaching of rocks under or adjacent to the deposits.Specific metal associations in SEDEX and lithogene deposits may reflect confinement of fluid flow to and derivation of metals from specific source rock types. Variable metal associations in VMS and magmatichydrothermal deposits may reflect derivation of metals from a more diverse suite of rocks by convecting hydrothermal systems and processes related to the generation of magma. The discovery rate for silver-rich deposits has accelerated during the past decade, with new deposit types, metal associations, and exploration models being identified that provide numerous exploration and research opportunities.

Improving Water Use Efficiency of Lettuce (Lactuca sativa L.) Using Phosphorous Fertilizers.

PubMed

Alkhader, Asad M F; Abu Rayyan, Azmi M

2013-01-01

A greenhouse pot experiment was conducted to evaluate the effect of phosphorous (P) fertilizers application to an alkaline calcareous soil on the water use efficiency (WUE) of lettuce cultivar "robinson" of iceberg type. Head fresh and dry weights, total water applied and WUE were affected significantly by the P fertilizer type and rate. P fertilizers addition induced a significant enhancement in the WUE and fresh and dry weights of the crop. A local phosphate rock (PR) applied directly was found to be inferior to the other types of P fertilizers (Mono ammonium phosphate (MAP), Single superphosphate (SSP), and Di ammonium phosphate ((DAP)). MAP fertilizer at 375 and 500 kg P2O5/ha application rates recorded the highest significant values of head fresh weight and WUE, respectively.

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.

Database Dictionary for Ethiopian National Ground-Water Database (ENGDA) Data Fields

DTIC Science & Technology

2007-01-01

Coarse Sand Fine Sand Fine-Grained Sandstone Fractured Igneous and Metamorphic Rock Gravel Karst Limestone, Dolomite Medium Sand Medium-Grained...Coarse Sand; Fine Sand; Fine-Grained Sandstone; Fractured Igneous and Metamorphic Rock; Gravel; Karst Limestone/ Dolomite ; Medium Sand; Medium...aquifer lithology (rock type; Babcock and other, 2004). - 20 - Data Type: List, 1-character code C Consolidated porous sedimentary I Fractured

Geology and Our Environment. Environmental Education Curriculum. Revised.

ERIC Educational Resources Information Center

Topeka Public Schools, KS.

Rocks, and the soil formed from rock, play a major role in determining such particulars as the type of crops that can be grown in a specific area and the type of housing that can be constructed. Also, rocks may supply fuel and building materials, and provide information about the history of an area. This unit is constructed to expose secondary…

Application of Sr and O isotope relations to the petrogenesis of the alkaline rocks of the Red Hill complex, New Hampshire, USA

USGS Publications Warehouse

Foland, K.A.; Friedman, I.

1977-01-01

The Red Hill ring complex in central New Hampshire is composed of apparently cogenetic syenites, nepheline-sodalite syenite, and granite. The ages and petrogenetic relations among five of the six recognized units have been investigated by rubidiumstrontium and oxygen isotope analysis of whole rocks and separated minerals. Whole-rock samples from three syenite units are consistent with a single Rb-Sr isochron which gives an age of 198??3 m.y. and an initial (87Sr/86Sr)o ratio of 0.70330??0.00016 (??2 sigma; ??=1.42?? 10-11y-1). However, Sr isotope data for two other units, nepheline syenite and granite, are not consistent with this isochron but rather indicate higher initial ratios which range from 0.7033 to about 0.707. Whole-rock O isotope analyses give ??18O values which range from+6.2 to+9.3??? Sr and O isotope analyses on mineral separates indicate that observed whole-rock variations in (87Sr/86Sr)o are primary and are not due to any secondary process. The fact that the isotope systematics correlate with rock type, suggests that crustal interaction is likely to have played a significant role in the development of this over-and undersaturated association. Such process(es), while still not fully delineated, could be of fundamental importance to the genesis of associations of critically undersaturated and oversaturated intrusives. The data support the idea that interaction between magmas and crustal materials strongly influenced the compositional relations of similar complexes elsewhere including those of the White Mountain magma series. ?? 1977 Springer-Verlag.

Petrogenesis of the Alaskan-type mafic-ultramafic complex in the Makkah quadrangle, western Arabian Shield, Saudi Arabia

NASA Astrophysics Data System (ADS)

Habtoor, Abdelmonem; Ahmed, Ahmed Hassan; Harbi, Hesham

2016-10-01

The Makkah quadrangle is a part of the Jeddah terrane in the Precambrian basement, Western Arabian Shield of Saudi Arabia. Gabal Taftafan mafic-ultramafic complex lies within the central part of the Makkah quadrangle. The Taftafan mafic-ultramafic complex is a well-differentiated rock association which comprises of dunite core, hornblende- and plagioclase-bearing peridotites, troctolite, clinopyroxenite and marginal gabbro, in a distinctive zonal structure. The bulk-rock geochemistry of the Taftafan mafic-ultramafic rocks is characterized by a tholeiitic/sub-alkaline affinity with high Mg in the ultramafic core (0.84) and is systematically decreased towards the marginal gabbro (0.60). The patterns of trace elements show enrichment in the fluid-mobile elements (Sr, Ba) and a pronounced negative Nb anomaly which reflect a hydrous parental magma generated in a subduction tectonic setting. The mafic-ultramafic rocks of the Taftafan complex have low total rare earth elements (REE) displaying sub-parallel patterns leading to the assumption that these rocks are comagmatic and are formed by fractional crystallization from a common magma type. The platinum-group elements (PGE) content of all rock types in the Taftafan complex is very low, with ∑ PPGE > ∑ IPGE; displaying slightly positive slopes of the PGE distribution patterns. The chemistry of ferromagnesian minerals is characterized by a high forsterite (Fo) olivine with wide range (Fo91-67), from ultramafic core to the marginal gabbro, Ca-rich diopsidic clinopyroxene, and calcic hornblende. Orthopyroxene is almost absent from all rock types, or very rare when present. Hornblende and Ca-plagioclase possess the longest crystallization history since they are present in almost all rock types of the complex. Spinels in the dunite and hornblende-bearing peridotite core show homogeneous composition with intermediate Cr# (0.53-0.67). Plagioclase-bearing peridotite and troctolite have two exsolved types of spinel; Al-rich and Fe-rich varieties. All spinel varieties in the mafic-ultramafic rocks have high Fe3 + and TiO2 contents. The estimated melt composition in equilibrium with Gabal Taftafan complex is mostly similar to that of the SSZ boninitic magmas. The Taftafan mafic-ultramafic rocks show many similarities with the Alaskan-type mafic-ultramafic complexes, including the internal zonal lithology, bulk rock geochemistry, and mineral chemistry. Thus, it is neither related to a fragment of ophiolite sequence nor to the stratiform mafic-ultramafic intrusion. The location of the Taftafan complex along a major fracture zone parallel to the suture between Jeddah and Asir terranes in addition to the aforementioned striking similarities to the Alaskan-type complexes, suggests a formation in subduction-related setting from a common hydrous mafic magma.

Organic metamorphism in the California petroleum basins; Chapter A, Rock-Eval and vitrinite reflectance

USGS Publications Warehouse

Price, Leigh C.; Pawlewicz, Mark J.; Daws, Ted A.

1999-01-01

The results of ROCK-EVAL and vitrinite reflectance analyses of a large sample base from more than 70 wells located in three oil-rich California petroleum basins are reported. The cores from these wells have a wide range of present-day burial temperatures (40 ? to 220 ? C). The rocks in these basins were deposited under highly variable conditions, sometimes resulting in substantially different organic matter (OM) types in rocks tens of meters vertically apart from each other in one well. The kinetic response of these different OM types to equivalent wellknown burial histories is a pivotal point of this study. In the Los Angeles and Ventura Basins, rock organic-richness significantly increased with depth, as did kerogen hydrogen content, and the percentage of fine-grained versus coarsegrained rocks. The shales in these basins are perceived as containing primarily hydrogen-rich amorphous OM. In actuality, the shallowest 2,000 to 3,000 m of rocks in the basins, and at least the upper 6,000 m of rocks in parts of the Los Angeles Basin central syncline, are dominated by type III/IV OM. In the Los Angeles Basin, mainstage hydrocarbon (HC) generation commences in the type III/IV OM at present-day burial temperatures of 85 ? to 110 ? C, most likely around 100 ? C, and is largely complete by 220 ? C. In the Southern San Joaquin Valley Basin, mainstage HC generation commences in type III/IV OM at 150 ? C and is also largely complete by 220 ? C. In the Ventura Basin, mainstage HC generation commences above 140 ? C in type III/IV OM. The apparent lower temperatures for commencement of HC generation in the Los Angeles Basin are attributed to the fact that parts of the basin were cooled from maximal burial temperatures by increased meteoric water flows during the last glaciations. All aspects of organic metamorphism, including mainstage HC generation, are strongly suppressed in rocks with hydrogenrich OM in these basins. For example, ROCK-EVAL data suggest that mainstage HC generation has not commenced in rocks with hydrogen-rich OM at present-day temperatures of 198?C. This observation is attributed to much stronger bonds in hydrogen- rich OM compared to types III and IV OM and, therefore, significantly higher burial temperatures are required to break these bonds. This difference in OM kinetics has profound ramifications for petroleum-geochemical exploration models. Organic-matter characteristics inherited from original depositional conditions were overlaid on, and at times confused interpretation of, characteristics from organic metamorphism in all study areas. In all the basins examined in this study, immature fine-grained rocks occasionally had high to very high carbon-normalized concentrations of pre-generation indigenous bitumen. This unusual characteristic may be due to unique depositional conditions in these basins.

Basalt-trachybasalt samples in Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Edwards, Peter H.; Bridges, John C.; Wiens, Roger; Anderson, Ryan; Dyar, Darby; Fisk, Martin; Thompson, Lucy; Gasda, Patrick; Filiberto, Justin; Schwenzer, Susanne P.; Blaney, Diana; Hutchinson, Ian

2017-11-01

The ChemCam instrument on the Mars Science Laboratory (MSL) rover, Curiosity, observed numerous igneous float rocks and conglomerate clasts, reported previously. A new statistical analysis of single-laser-shot spectra of igneous targets observed by ChemCam shows a strong peak at 55 wt% SiO2 and 6 wt% total alkalis, with a minor secondary maximum at 47-51 wt% SiO2 and lower alkali content. The centers of these distributions, together with the rock textures, indicate that many of the ChemCam igneous targets are trachybasalts, Mg# = 27 but with a secondary concentration of basaltic material, with a focus of compositions around Mg# = 54. We suggest that all of these igneous rocks resulted from low-pressure, olivine-dominated fractionation of Adirondack (MER) class-type basalt compositions. This magmatism has subalkaline, tholeiitic affinities. The similarity of the basalt endmember to much of the Gale sediment compositions in the first 1000 sols of the MSL mission suggests that this type of Fe-rich, relatively low-Mg#, olivine tholeiite is the dominant constituent of the Gale catchment that is the source material for the fine-grained sediments in Gale. The similarity to many Gusev igneous compositions suggests that it is a major constituent of ancient Martian magmas, and distinct from the shergottite parental melts thought to be associated with Tharsis and the Northern Lowlands. The Gale Crater catchment sampled a mixture of this tholeiitic basalt along with alkaline igneous material, together giving some analogies to terrestrial intraplate magmatic provinces.

Palladium, platinum, and rhodium contents of rocks near the lower margin of the Stillwater complex, Montana.

USGS Publications Warehouse

Zientek, M.L.; Foose, M.P.; Leung, Mei

1986-01-01

Statistical summaries are reported for Pd, Pt and Rh contents of rocks from the lower part of the Stillwater complex, the underlying contact-metamorphosed sediments, and post-metamorphic dykes and sills wholly within the hornfelses. Variability of the data among the rock types is attributed largely to differences in sulphide content. Non-correlation of sulphur with platinum-group assays of many rock types leads to the suggestion that the immiscible sulphide and silicate liquids did not completely equilibrate with respect to platinum-group elements. -G.J.N.

The surface abundance and stratigraphy of lunar rocks from data about their albedo

NASA Technical Reports Server (NTRS)

Shevchenko, V. V.

1977-01-01

The data pf ground-based studies and surveys of the lunar surface by the Zond and Apollo spacecraft have been used to construct an albedo map covering 80 percent of the lunar sphere. Statistical analysis of the distribution of areas with various albedos shows several types of lunar surface. Comparison of albedo data for maria and continental areas with the results of geochemical orbital surveys allows the identification of the types of surface with known types of lunar rock. The aluminum/silcon and magnesium/silicon ratios as measured by the geochemical experiments on the Apollo 15 and Apollo 16 spacecraft were used as an indication of the chemical composition of the rock. The relationship of the relative aluminum content to the age of crystalline rocks allows a direct dependence to be constructed between the mean albedo of areas and the age of the rocks of which they are composed.

Characterization of Rock Types at Meridiani Planum, Mars using MER 13-Filter Pancam Spectra

NASA Technical Reports Server (NTRS)

Nuding, D. L.; Cohen, B. A.

2009-01-01

The Mars Exploration Rover Opportunity has traversed more than 13 km across Meridiani Planum, finding evidence of ancient aqueous environments that, in the past, may have been suitable for life. Meridiani bedrock along the rover traverse is a mixture in composition and bulk mineralogy between a sulfate-rich sedimentary rock and hematite spherules ("blueberries"). On top of the bedrock, numerous loose rocks exist. These rocks consist of both local bedrock and "cobbles" of foreign origin. The cobbles provide a window into lithologic diversity and a chance to understand other types of martian rocks and meteorites. This study was also an attempt to establish a method to expand upon those of Mini-TES to remotely identify rocks of interest to make efficient use of the rover s current resources.

Direct measurement of 3D elastic anisotropy on rocks from the Ivrea zone (Southern Alps, NW Italy)

NASA Astrophysics Data System (ADS)

Pros, Z.; Lokajíček, T.; Přikryl, R.; Klíma, K.

2003-07-01

Lower crustal and upper mantle rocks exposed at the earth's surface present direct possibility to measure their physical properties that must be, in other cases, interpreted using indirect methods. The results of these direct measurements can be then used for the corrections of models based on the indirect data. Elastic properties are among the most important parameters studied in geophysics and employed in many fields of earth sciences. In laboratory, dynamic elastic properties are commonly tested in three mutually perpendicular directions. The spatial distribution of P- and S-wave velocities are then computed using textural data, modal composition, density and elastic constants. During such computation, it is virtually impossible to involve all microfabric parameters like different types of microcracking, micropores, mineral alteration or quality of grain boundaries. In this study, complete 3D ultrasonic transmission of spherical samples in 132 independent directions at several levels of confining pressure up to 400 MPa has been employed for study of selected mafic and ultrabasic rocks sampled in and nearby Balmuccia ultrabasic massif (Ivrea zone, Southern Alps, NW Italy). This method revealed large directional variance of maximum P-wave velocity and different symmetries (orthorhombic vs. transversal isotropic) of elastic waves 3D distribution that has not been recorded on these rocks before. Moreover, one dunite sample exhibits P-wave velocity approaching to that of olivine single crystal being interpreted as influence of CPO.

Partitioning mechanisms of predator interference in different habitats.

PubMed

Griffen, Blaine D; Byers, James E

2006-01-01

Prey are often consumed by multiple predator species. Predation rates on shared prey species measured in isolation often do not combine additively due to interference or facilitation among the predator species. Furthermore, the strength of predator interactions and resulting prey mortality may change with habitat type. We experimentally examined predation on amphipods in rock and algal habitats by two species of intertidal crabs, Hemigrapsus sanguineus (top predators) and Carcinus maenas (intermediate predators). Algae provided a safer habitat for amphipods when they were exposed to only a single predator species. When both predator species were present, mortality of amphipods was less than additive in both habitats. However, amphipod mortality was reduced more in rock than algal habitat because intermediate predators were less protected in rock habitat and were increasingly targeted by omnivorous top predators. We found that prey mortality in general was reduced by (1) altered foraging behavior of intermediate predators in the presence of top predators, (2) top predators switching to foraging on intermediate predators rather than shared prey, and (3) density reduction of intermediate predators. The relative importance of these three mechanisms was the same in both habitats; however, the magnitude of each was greater in rock habitat. Our study demonstrates that the strength of specific mechanisms of interference between top and intermediate predators can be quantified but cautions that these results may be habitat specific.

The problem of genesis and systematic of sedimentary units of hydrocarbon reservoirs

NASA Astrophysics Data System (ADS)

Zhilina, E. N.; Chernova, O. S.

2017-12-01

The problem of identifying and ranking sedimentation, facies associations and their constituent parts - lithogenetic types of sedimentary rocks was considered. As a basis for paleo-sedimentary modelling, the author has developed a classification for terrigenous natural reservoirs,that for the first time links separate sedimentological units into a single hierarchical system. Hierarchy ranking levels are based on a compilation of global knowledge and experience in sediment geology, sedimentological study and systematization, and data from deep-well coresrepresentingJurassichydrocarbon-bearing formationsof the southeastern margin of the Western Siberian sedimentary basin.

Mineralogical, textural, geochemical and thermometric characteristics of Central Anatolian fluorites (Turkey): Tracing the origin of post-magmatic fluids

NASA Astrophysics Data System (ADS)

Cosanay, Pelin; Mutlu, Halim; Koc, Sükrü; Cevik, Nihal; Oztürk, Ceyda; Varol, Ece

2016-04-01

In this study, we investigate the spatial distribution of fluorite veins in Central Anatolia with emphasis on mineralogical, textural, geochemical and thermometric variations. The studied fluorite mineralizations (Kaman, Akçakent, Pöhrenk and Şefaatli mineralizations from west to east) are located on northern part of Kırşehir Massif which is a part of Central Anatolian Crystalline Complex that is bordered by the İzmir-Ankara-Erzincan Suture Zone. The Kaman, Akçakent and Şefaatli fluorite deposits are formed in association with magmatic rocks such as syenite and monzonite / monzodiorite in composition which are of Upper Cretaceous age. Fluorite in these deposits occurs as purple- and green-colored stockwork veins and/or disseminations along fault/fracture systems and is accompanied by quartz and rare pyrite. The Pöhrenk ore, however, is precipitated as space filling-breccia type within karstic voids of Eocene limestones and marl levels. The silicification/carbonatization and barite occurrences are found as the main alteration and secondary products of mineralization. Thickness of fluorite veins is between 2 and 30 cm. ΣREE contents of host rocks and fluorite veins are in the range of 2-806 ppm and 20-390 ppm, respectively. In element variation diagrams constructed for both host rocks and fluorite mineralizations, LREE concentrations are found to be greater than HREEs. REE contents of green-colored fluorites are about 10-fold higher than those of purple-colored ones. Negative Ce and Eu anomalies indicate high oxygen fugacity for the mineralizing fluids. Fluid inclusion studies indicated three different types of inclusions: 1) two-phase (liquid-vapor) primary and secondary inclusions, 2) single-phase (liquid) primary and secondary inclusions and 3) two-phase (liquid-vapor) and single-phase (liquid) pseudo-secondary inclusions. Results of homogenization temperatures from a number of about 200 measurements chiefly on fluorite and less often quartz and barite crystals point to a temperature range of 90-210°C and a salinity range of 0.2 to 23.0 NaCl equivalent wt%. Our ongoing survey which has been further focused on the time of mineralization and Sr-Nd isotope compositions of fluorites and host rocks as well as stable isotope systematics of accessory minerals will lead to a better understanding of the origin of mineralizing fluids that precipitated Central Anatolian fluorites.

Origin and evolution of phyllosilicate deformation bands in the poorly lithified sandstones of the Rio do Peixe Basin, NE Brazil

NASA Astrophysics Data System (ADS)

Nogueira, Francisco; Nicchio, Matheus; Balsamo, Fabrizio; Bezerra, Francisco; Souza, Jorge; Carvalho, Bruno; Storti, Fabrizio

2017-04-01

In this work we describe the genetic processes and the microstructural evolution of phylossilicate deformation bands developed in poorly lithified, high porosity sandstones of the Rio do Peixe Basin, Northeast Brazil. The studied deformation bands occur in damage zones of NE-SW and NW-SE transtensional faults that exhibit well developed anastomosed clusters, with a thickness varying from tens of centimeters to 1 meter. The Host rocks are arkosic to lithic arkosic coarse sandstones to fine conglomerate and with less than 1% of clay content in the matrix. Based on (i) field observations, (ii) clay amount in deformation band cores and (iii) clay mineral arrangements in deformation bands cores, we identified two types of phyllosilicate deformation bands: (1) clay smearing deformation bands and (2) phyllosilicate deformation bands formed by clay authigenesis. The former occur only in fault zones that cut across clay-rich layers and are characterized by 45-50% of clay content. Single element chemical analysis indicates that the composition of clay minerals in clay smearing deformation bands is similar to that of clay-rich layers in the host rocks. The dominant deformation mechanism is particulate flow, which produces preferential alignments of grains and clay minerals. Only subordinate cataclasis occurs. Based on microstructural fabrics, three evolutionary stages can be identified for phyllosilicate deformation bands formed by clay authigenesis. The first one is characterized by preferentially cataclasis and weathering of feldspars. Clay concentration is relatively low, reaching 15-20%, with preferential concentration where crushed feldspar abundance is higher. The second stage is characterized by clay migration within deformation bands, to form continuous films with more than 20-25% of clay concentration. In the last stage clay mineral fabric re-organization occurs, forming well a developed S-C foliation. Clay concentration exceeds 35%. Single element chemical analysis indicates that the only external element present in phyllosilicate deformation bands formed by clay authigenesis is iron oxide. This feature suggests formation at very shallow depth, in the vadose zone where fluid flow preferentially occurs by capillarity in deformation band cores. Petrophysical analysis shows that both types of phyllosilicate deformation bands have high sealing potential. Clay smearing deformation bands reduce rock permeability by three orders of magnitude whereas phyllosilicate deformation bands formed by authigenesis causes permeability reduction of about two orders of magnitude with respect to the corresponding host rock.

A new heat flux model for the Antarctic Peninsula incorporating spatially variable upper crustal radiogenic heat production

NASA Astrophysics Data System (ADS)

Burton-Johnson, A.; Halpin, J. A.; Whittaker, J. M.; Graham, F. S.; Watson, S. J.

2017-06-01

A new method for modeling heat flux shows that the upper crust contributes up to 70% of the Antarctic Peninsula's subglacial heat flux and that heat flux values are more variable at smaller spatial resolutions than geophysical methods can resolve. Results indicate a higher heat flux on the east and south of the Peninsula (mean 81 mW m-2) where silicic rocks predominate, than on the west and north (mean 67 mW m-2) where volcanic arc and quartzose sediments are dominant. While the data supports the contribution of heat-producing element-enriched granitic rocks to high heat flux values, sedimentary rocks can be of comparative importance dependent on their provenance and petrography. Models of subglacial heat flux must utilize a heterogeneous upper crust with variable radioactive heat production if they are to accurately predict basal conditions of the ice sheet. Our new methodology and data set facilitate improved numerical model simulations of ice sheet dynamics.