Photogeologic mapping in central southwest Bahia, using LANDSAT-1 multispectral images. [Brazil

NASA Technical Reports Server (NTRS)

Dejesusparada, N. (Principal Investigator); Ohara, T.

1981-01-01

The interpretation of LANDSAT multispectral imagery for geologic mapping of central southwest Bahia, Brazil is described. Surface features such as drainage, topography, vegetation and land use are identified. The area is composed of low grade Precambrian rocks covered by Mezozoic and Cenozoic sediments. The principal mineral prospects of economic value are fluorite and calcareous rocks. Gold, calcite, rock crystal, copper, potassium nitrate and alumina were also identified.

Mars' "White Rock" feature lacks evidence of an aqueous origin: Results from Mars Global Surveyor

USGS Publications Warehouse

Ruff, S.W.; Christensen, P.R.; Clark, R.N.; Kieffer, H.H.; Malin, M.C.; Bandfield, J.L.; Jakosky, B.M.; Lane, M.D.; Mellon, M.T.; Presley, M.A.

2001-01-01

The "White Rock" feature on Mars has long been viewed as a type example for a Martian playa largely because of its apparent high albedo along with its location in a topographic basin (a crater). Data from the Mars Global Surveyor Thermal Emission Spectrometer (TES) demonstrate that White Rock is not anomalously bright relative to other Martian bright regions, reducing the significance of its albedo and weakening the analogy to terrestrial playas. Its thermal inertia value indicates that it is not mantled by a layer of loose dust, nor is it bedrock. The thermal infrared spectrum of White Rock shows no obvious features of carbonates or sulfates and is, in fact, spectrally flat. Images from the Mars Orbiter Camera show that the White Rock massifs are consolidated enough to retain slopes and allow the passage of saltating grains over their surfaces. Material appears to be shed from the massifs and is concentrated at the crests of nearby bedforms. One explanation for these observations is that White Rock is an eroded accumulation of compacted or weakly cemented aeolian sediment. Copyright 2001 by the American Geophysical Union.

The fate of iron on Mars: Mechanism of oxidation of basaltic minerals to ferric-bearing assemblages

NASA Technical Reports Server (NTRS)

Burns, Roger G.

1992-01-01

Perhaps the most conspicuous indication that chemical weathering has occurred on the surface of Mars is the overall color of the red planet and the spectroscopic features that identify ferric-bearing assemblages in the martian regolith. Apparently, Fe(2+) ions in primary minerals in parent igneous rocks on the martian surface have been oxidized to ferric iron, which occurs in degradation products that now constitute the regolith. The mineralogy of the unweathered igneous rocks prior to weathering on the martian surface is reasonably well constrained, mainly as a result of petrographic studies of the SNC meteorites. However, the alteration products resulting from oxidative weathering of these rocks are less well-constrained. The topics covered include the following: primary rocks subjected to chemical weathering; dissolution processes; oxidation of dissolved Fe(2+); mechanism of polymerization of hydrous ferric oxides; terrestrial occurrences of ferromagnesian smectites; and dehydroxylated Mg-Fe smectites on Mars.

Regulation of osteogenesis by micro/nano hierarchical titanium surfaces through a Rock-Wnt5a feedback loop.

PubMed

Yu, Yonglin; Shen, Xinkun; Liu, Junjie; Hu, Yan; Ran, Qichun; Mu, Caiyun; Cai, Kaiyong

2018-05-28

Titanium substrates with micro/nano hierarchical features could positively mediate the osteogenesis of a titanium implant; nevertheless, the underlying molecular mechanism needs to be further revealed. In this work, we fabricated a micro/nano hierarchically structured Ti (MNT) sample and attempted to evaluate its topography-mediated biological effects and potential molecular mechanisms in vitro. The results proved that MNT could not only affect cell morphology and osteogenic differentiation, but also regulate ROCK activity cell biological functions of osteoblasts involved in ROCK activation, β-catenin accumulation, and high-Wnt5a expression in respect to topographical features. Moreover, blockade of ROCK activation resulted in significant inhibition of cell differentiation and Wnt5a expression. Furthermore, the anti-Wnt5a significantly down-regulated ROCK activity. In short, these results indicate the important role of ROCK-Wnt5a feedback loop in regulating cell differentiation by topographies. Copyright © 2018. Published by Elsevier B.V.

Automatic crack detection method for loaded coal in vibration failure process

PubMed Central

Li, Chengwu

2017-01-01

In the coal mining process, the destabilization of loaded coal mass is a prerequisite for coal and rock dynamic disaster, and surface cracks of the coal and rock mass are important indicators, reflecting the current state of the coal body. The detection of surface cracks in the coal body plays an important role in coal mine safety monitoring. In this paper, a method for detecting the surface cracks of loaded coal by a vibration failure process is proposed based on the characteristics of the surface cracks of coal and support vector machine (SVM). A large number of cracked images are obtained by establishing a vibration-induced failure test system and industrial camera. Histogram equalization and a hysteresis threshold algorithm were used to reduce the noise and emphasize the crack; then, 600 images and regions, including cracks and non-cracks, were manually labelled. In the crack feature extraction stage, eight features of the cracks are extracted to distinguish cracks from other objects. Finally, a crack identification model with an accuracy over 95% was trained by inputting the labelled sample images into the SVM classifier. The experimental results show that the proposed algorithm has a higher accuracy than the conventional algorithm and can effectively identify cracks on the surface of the coal and rock mass automatically. PMID:28973032

Automatic crack detection method for loaded coal in vibration failure process.

PubMed

Li, Chengwu; Ai, Dihao

2017-01-01

In the coal mining process, the destabilization of loaded coal mass is a prerequisite for coal and rock dynamic disaster, and surface cracks of the coal and rock mass are important indicators, reflecting the current state of the coal body. The detection of surface cracks in the coal body plays an important role in coal mine safety monitoring. In this paper, a method for detecting the surface cracks of loaded coal by a vibration failure process is proposed based on the characteristics of the surface cracks of coal and support vector machine (SVM). A large number of cracked images are obtained by establishing a vibration-induced failure test system and industrial camera. Histogram equalization and a hysteresis threshold algorithm were used to reduce the noise and emphasize the crack; then, 600 images and regions, including cracks and non-cracks, were manually labelled. In the crack feature extraction stage, eight features of the cracks are extracted to distinguish cracks from other objects. Finally, a crack identification model with an accuracy over 95% was trained by inputting the labelled sample images into the SVM classifier. The experimental results show that the proposed algorithm has a higher accuracy than the conventional algorithm and can effectively identify cracks on the surface of the coal and rock mass automatically.

Insights on surface spalling of rock

NASA Astrophysics Data System (ADS)

Tarokh, Ali; Kao, Chu-Shu; Fakhimi, Ali; Labuz, Joseph F.

2016-07-01

Surface spalling is a complex failure phenomenon that features crack propagation and detachment of thin pieces of rock near free surfaces, particularly in brittle rock around underground excavations when large in situ stresses are involved. A surface instability apparatus was used to study failure of rock close to a free surface, and damage evolution was monitored by digital image correlation (DIC). Lateral displacement at the free face was used as the feedback signal to control the post-peak response of the specimen. DIC was implemented in order to obtain the incremental displacement fields during the spalling process. Displacement fields were computed in the early stage of loading as well as close to the peak stress. Fracture from the spalling phenomenon was revealed by incremental lateral displacement contours. The axial and lateral displacements suggested that the displacement gradient was uniform in both directions at early loading stages and as the load increased, the free-face effect started to influence the displacements, especially the lateral displacement field. A numerical approach, based on the discrete element method, was developed and validated from element testing. Damage evolution and localization observed in numerical simulations were similar to those observed in experiments. By performing simulations in two- and three-dimensions, it was revealed that the intermediate principal stress and platen-rock interfaces have important effects on simulation of surface spalling.

Micromorphological features of the fine earth and skeletal fractions of soils of West Antarctica in the areas of Russian Antarctic stations

NASA Astrophysics Data System (ADS)

Abakumov, E. V.; Gagarina, E. I.; Sapega, V. F.; Vlasov, D. Yu.

2013-12-01

Micromorphological features of the fine earth and skeletal fractions of soils of West Antarctica forming under different conditions of pedogenesis have been studied in the areas of Russian Antarctic stations. The processes of mineral weathering and alteration of rock fragments are more pronounced in the Subantarctic soils with better developed humification and immobilization of iron compounds under conditions of surface overmoistening. The biogenic accumulative processes in the soils of King George Island result in the appearance of initial forms of humic plasma that have not been detected in the Antarctic soils in the areas of the Russkaya and Leningradskaya stations. Humus films on mineral grains are present in the soils of King George Island, and organic plasmic material is present in the ornithogenic soils under penguin guano on Lindsey Island. High-latitude Antarctic soils may contain surface concentrations of organic matter; rock fragments are covered by iron oxides and soluble salts. The formation of amorphous organic plasma takes place in the ornithogenic soils of Lindsey Island. The microprobe analysis indicates the presence of local concentrations of organic matter and pedogenic compounds not only on the surface of rock fragments but also in the fissures inside them. This analysis has also proved the translocation of guano-derived organic substances inside rock fragments through a system of fissures in the soils of Lindsey Island and the development of a network of pores inside rock fragments in the soils of King George Island.

Remotely sensed detection of sulfates on Mars: Laboratory measurements and spacecraft observations

NASA Astrophysics Data System (ADS)

Cooper, Christopher David

Visible, near-infrared, and mid-infrared spectroscopic measurements were made of physically realistic analogs of Martian soil containing silicates and sulfates. These measurements indicate that the physical structure of soil will control its spectroscopic properties. Orbital measurements from the Thermal Emission Spectrometer (TES) identified features similar to those seen in the laboratory mixtures. Maps were made of this sulfate-cemented soil which indicated that the presence of this material is not geographically controlled and hints at an origin for duricrust in atmosphere-surface interactions. Further confirmation comes from combining data from TES and the Imaging Spectrometer for Mars (ISM). This data shows a congruence between sulfate spectral features and water features. The likely form of the mappable sulfate in Martian soils is therefore a cemented mixture of hydrated sulfate mixed with silicates and oxides derived from crustal rocks. The combination of ISM and TES spectra in particular and spectra from multiple wavelength regimes in general also is an excellent technique for addressing other problems of interest regarding the geology of Mars. A number of topics including rock coatings in Syrtis Major and the nature of low albedo rock assemblages are addressed. Syrtis Major is found to behave differently in the thermal and near infrared, likely indicating that the spectral features are not related to simple coatings but perhaps processes like penetrative oxidation. TES Type I rocks are found to be high in pyroxene, but TES Type II rocks do not have a correlation with pyroxene. Spectral mixing trends indicate that dust and rock are the dominant two variables in surface composition on a large scale. A smaller mixing trend involves the physical breakup of sulfate-cemented soils into a loose, fine-grained, but still hydrated form. In all, this work provides strong evidence for the global identification and distribution of sulfate minerals in the Martian soil.

Erosion-tectonics feedbacks in shaping the landscape: An example from the Mekele Outlier (Tigray, Ethiopia)

NASA Astrophysics Data System (ADS)

Sembroni, Andrea; Molin, Paola; Dramis, Francesco; Faccenna, Claudio; Abebe, Bekele

2017-05-01

An outlier consists of an area of younger rocks surrounded by older ones. Its formation is mainly related to the erosion of surrounding rocks which causes the interruption of the original continuity of the rocks. Because of its origin, an outlier is an important witness of the paleogeography of a region and, therefore, essential to understand its topographic and geological evolution. The Mekele Outlier (N Ethiopia) is characterized by poorly incised Mesozoic marine sediments and dolerites (∼2000 m in elevation), surrounded by strongly eroded Precambrian and Paleozoic rocks and Tertiary volcanic deposits in a context of a mantle supported topography. In the past, studies about the Mekele outlier focused mainly in the mere description of the stratigraphic and tectonic settings without taking into account the feedback between surface and deep processes in shaping such peculiar feature. In this study we present the geological and geomorphometric analyses of the Mekele Outlier taking into account the general topographic features (slope map, swath profiles, local relief), the river network and the principal tectonic lineaments of the outlier. The results trace the evolution of the study area as related not only to the mere erosion of the surrounding rocks but to a complex interaction between surface and deep processes where the lithology played a crucial role.

A phylogenetic test for adaptive convergence in rock-dwelling lizards.

PubMed

Revell, Liam J; Johnson, Michele A; Schulte, James A; Kolbe, Jason J; Losos, Jonathan B

2007-12-01

Phenotypic similarity of species occupying similar habitats has long been taken as strong evidence of adaptation, but this approach implicitly assumes that similarity is evolutionarily derived. However, even derived similarities may not represent convergent adaptation if the similarities did not evolve as a result of the same selection pressures; an alternative possibility is that the similar features evolved for different reasons, but subsequently allowed the species to occupy the same habitat, in which case the convergent evolution of the same feature by species occupying similar habitats would be the result of exaptation. Many lizard lineages have evolved to occupy vertical rock surfaces, a habitat that places strong functional and ecological demands on lizards. We examined four clades in which species that use vertical rock surfaces exhibit long hindlimbs and flattened bodies. Morphological change on the phylogenetic branches leading to the rock-dwelling species in the four clades differed from change on other branches of the phylogeny; evolutionary transitions to rock-dwelling generally were associated with increases in limb length and decreases in head depth. Examination of particular characters revealed several different patterns of evolutionary change. Rock-dwelling lizards exhibited similarities in head depth as a result of both adaptation and exaptation. Moreover, even though rock-dwelling species generally had longer limbs than their close relatives, clade-level differences in limb length led to an overall lack of difference between rock- and non-rock-dwelling lizards. These results indicate that evolutionary change in the same direction in independent lineages does not necessarily produce convergence, and that the existence of similar advantageous structures among species independently occupying the same environment may not indicate adaptation.

Weathered stony meteorites from Victoria Land, Antarctica, as possible guides to rock weathering on Mars

NASA Technical Reports Server (NTRS)

Gooding, J. L.

1984-01-01

Parallel studies of Martian geomorphic features and their analogs on Earth continue to be fruitful in deciphering the geologic history of Mars. In the context of rock weathering, the Earth-analog approach is admirably served by the study of meteorites recovered from ice sheets in Antarctica. The weathering environment of Victoria Land possesses several Mars-like attributes. Four of the five Antarctic meteorites being studied contain rust and EETA79005 further possesses a conspicuous, dark, weathering rind on one side. Secondary minerals (rust and salts) occur both on the surfaces and interiors of some of the samples and textural evidence indicates that such secondary mineralization contributed to physical weathering (by salt riving) of the rocks. Several different rust morphologies occur and emphasis is being placed on identifying the phase compositions of the various rust occurrances. A thorough understanding of terrestrial weathering features of the meteorites is a prerequisite for identifying possible Martian weathering features (if such features exist) that might be postulated to occur in some meteorites.

Wind Carved Rock

NASA Image and Video Library

2016-10-19

The distinctively fluted surface and elongated hills in this image in Medusae Fossae are caused by wind erosion of a soft fine-grained rock. Called yardangs, these features are aligned with the prevailing wind direction. This wind direction would have dominated for a very long time to carve these large-scale features into the exposed rock we see today. Yardangs not only reveal the strength and direction of historic winds, but also reveal something of the host rock itself. Close inspection by HiRISE shows an absence of boulders or rubble, especially along steep yardang cliffs and buttresses. The absence of rubble and the scale of the yardangs tells us that the host rock consists only of weakly cemented fine granules in tens of meters or more thick deposits. Such deposits could have come from extended settling of volcanic ash, atmospheric dust, or accumulations of wind deposited fine sands. After a time these deposits became cemented and cohesive, illustrated by the high standing relief and exposed cliffs. http://photojournal.jpl.nasa.gov/catalog/PIA21111

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

NASA Astrophysics Data System (ADS)

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

2017-11-01

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

Tectonism

NASA Image and Video Library

2011-10-24

This image from NASA 2001 Mars Odyssey spacecraft shows evidence of tectonic stresses that deform and fracture rocks and planetary surfaces. Right angles seen here are a good indication that the feature was formed by tectonic stresses.

Topography, surface properties, and tectonic evolution. [of Venus and comparison with earth

NASA Technical Reports Server (NTRS)

Mcgill, G. E.; Warner, J. L.; Malin, M. C.; Arvidson, R. E.; Eliason, E.; Nozette, S.; Reasenberg, R. D.

1983-01-01

Differences in atmospheric composition, atmospheric and lithospheric temperature, and perhaps mantle composition, suggest that the rock cycle on Venus is not similar to the earth's. While radar data are not consistent with a thick, widespread and porous regolith like that of the moon, wind-transported regolith could be cemented into sedimentary rock that would be indistinguishable from other rocks in radar returns. The elevation spectrum of Venus is strongly unimodal, in contrast to the earth. Most topographic features of Venus remain enigmatic. Two types of tectonic model are proposed: a lithosphere too thick or buoyant to participate in convective flow, and a lithosphere which, in participating in convective flow, implies the existence of plate tectonics. Features consistent with earth-like plate tectonics have not been recognized.

Slickenside formation by surface melting during the mechanical excavation of rock

NASA Astrophysics Data System (ADS)

Spray, John G.

This work discusses the nature and origin of slickensides generated by the impingement of high-carbon steel teeth on sandstone during the mechanical excavation of boulders by back shovel and front loader. The slickensides show a number of morphological features that can be related to the direction and sense of tooth displacement, including striations, carrot-shaped grooves, curved fractures and steps. Scanning and transmission electron microscopy reveal that the slickensides comprise a layer of Fe-enriched, glass-bonded gouge (≤150 μm thick). The estimated shear stresses and velocities realized at the tooth-rock interface (175 MPa at 1 m s -1 for the back shovel and 100 MPa at 2 m s -1 for the front loader) indicate that a heat production of 150-200 MW m -2 and mean surface temperature of 1400-1700°C were achieved. XRF and microprobe analyses confirm that localized bulk melting and Fe-enrichment of the surface occurred during slip. The excavator-generated slickensides provide an analogue for the effects of a single co-seismic event in the evolution of a shallow, relatively dry fault surface. From a simple consideration of energetics under these conditions, it is apparent that localized surface melting should be commonplace. Such an analogue may be useful as a guide for recognizing melt features in natural slickensides, features that would otherwise tend to be obscured during lengthier periods of interseismic surface modification.

Geological and Seismic Data Mining For The Development of An Interpretation System Within The Alptransit Project

NASA Astrophysics Data System (ADS)

Klose, C. D.; Giese, R.; Löw, S.; Borm, G.

Especially for deep underground excavations, the prediction of the locations of small- scale hazardous geotechnical structures is nearly impossible when exploration is re- stricted to surface based methods. Hence, for the AlpTransit base tunnels, exploration ahead has become an essential component of the excavation plan. The project de- scribed in this talk aims at improving the technology for the geological interpretation of reflection seismic data. The discovered geological-seismic relations will be used to develop an interpretation system based on artificial intelligence to predict hazardous geotechnical structures of the advancing tunnel face. This talk gives, at first, an overview about the data mining of geological and seismic properties of metamorphic rocks within the Penninic gneiss zone in Southern Switzer- land. The data results from measurements of a specific geophysical prediction system developed by the GFZ Potsdam, Germany, along the 2600 m long and 1400 m deep Faido access tunnel. The goal is to find those seismic features (i.e. compression and shear wave velocities, velocity ratios and velocity gradients) which show a significant relation to geological properties (i.e. fracturing and fabric features). The seismic properties were acquired from different tomograms, whereas the geolog- ical features derive from tunnel face maps. The features are statistically compared with the seismic rock properties taking into account the different methods used for the tunnel excavation (TBM and Drill/Blast). Fracturing and the mica content stay in a positive relation to the velocity values. Both, P- and S-wave velocities near the tunnel surface describe the petrology better, whereas in the interior of the rock mass they correlate to natural micro- and macro-scopic fractures surrounding tectonites, i.e. cataclasites. The latter lie outside of the excavation damage zone and the tunnel loos- ening zone. The shear wave velocities are better indicators for rock fracturing than compression wave velocities. The velocity ratios indicate the mica content and the water content of the rocks.

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

NASA Technical Reports Server (NTRS)

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

2003-01-01

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

Friction and dynamics of rock avalanches travelling on glaciers

NASA Astrophysics Data System (ADS)

De Blasio, Fabio Vittorio

2014-05-01

Rock avalanches travelling on glaciers often exhibit effective friction coefficient lower than those on a rocky terrain. After briefly considering some data of rock avalanches on glaciers, the physics of sliding of solid objects on icy surfaces is reviewed, and a model is put forward for the mechanics of rock avalanche sliding on ice accounting for the formation of a natural lubricating layer. It is suggested that at the beginning of the flow of a rock avalanche, friction results from rocky blocks ploughing on ice. As the erosion continues, a gouge of ice particles results, which clogs the interstices between blocks and may partially melt as a consequence of the production of frictional heat. This conceptual model is numerically investigated for a slab travelling on ice. The results show an increase in mobility as a function of slab thickness, travelled length, and the gravity field, in agreement with case studies. The results are useful to interpret the peculiar features of rock avalanches travelling on icy surfaces such as digitations, out-runner blocks, and longitudinal furrows. The lubrication theory for landslides on ice proposed here may provide a framework for understanding landslides on Earth and for future modelling; in addition, it may help elucidate the presence of similar landslide deposits on the surface of Mars.

Dissolution-Enlarged Fractures Imaging Using Electrical Resistivity Tomography (ERT)

NASA Astrophysics Data System (ADS)

Siami-Irdemoosa, Elnaz

In recent years the electrical imaging techniques have been largely applied to geotechnical and environmental investigations. These techniques have proven to be the best geophysical methods for site investigations in karst terrain, particularly when the overburden soil is clay-dominated. Karst is terrain with a special landscape and distinctive hydrological system developed by dissolution of rocks, particularly carbonate rocks such as limestone and dolomite, made by enlarging fractures into underground conduits that can enlarge into caverns, and in some cases collapse to form sinkholes. Bedding planes, joints, and faults are the principal structural guides for underground flow and dissolution in almost all karstified rocks. Despite the important role of fractures in karst development, the geometry of dissolution-enlarged fractures remain poorly unknown. These features are characterized by an strong contrast with the surrounding formations in terms of physical properties, such as electrical resistivity. Electrical resistivity tomography (ERT) was used as the primary geophysical tool to image the subsurface in a karst terrain in Greene County, Missouri. Pattern, orientation and density of the joint sets were interpreted from ERT data in the investigation site. The Multi-channel Analysis of Surface Wave (MASW) method and coring were employed to validate the interpretation results. Two sets of orthogonal visually prominent joints have been identified in the investigation site: north-south trending joint sets and west-east trending joint sets. However, most of the visually prominent joint sets are associated with either cultural features that concentrate runoff, natural surface drainage features or natural surface drainage.

Mars Pathfinder Landing Site: Evidence for a Change in Wind Regime from Lander and Orbiter Data

NASA Technical Reports Server (NTRS)

Greeley, Ronald; Kraft, Michael D.; Kuzmin, Ruslan O.; Bridges, Nathan T.

2000-01-01

Surface features related to the wind are observed in the vicinity of the Mars Pathfinder (MPR landing site data from the lander and in data from orbit by the Viking Orbiter and Mars Global Surveyor missions. Features seen from the surface include wind tails associated with small rocks, barchanoid duneforms, ripplelike patterns, and ventifact flutes cut into some rocks. Features seen from orbit include wind tails associated with impact craters, ridges inferred to be duneforms, and modified crater rims interpreted to have been eroded and mantled by windblown material. The orientations of these features show two prevailing directions. One is inferred to represent winds from the northeast, which is consistent with strongest winds predicted by a general circulation model to occur during the Martian northern winter under current conditions. A second wind blowing from the ESE was responsible for modifying the crater rims and cutting some of the ventifacts. The two wind regimes could reflect a change in climate related to Mars' obliquity or some other, unknown factor. Regardless of the cause, the MPF area has been subjected to a complex pattern of winds and supply of small particles, and the original surface formed by sedimentary processes from Tiu and Ares Vallis flooding events has been modified by repeated burial and exhumation.

Seismic Hazard Assessment for the Baku City and Absheron Peninsula, Azerbaijan

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

Babayev, Gulam R.

2006-03-23

This paper deals with the seismic hazard assessment for Baku and the Absheron peninsula. The assessment is based on the information on the features of earthquake ground motion excitation, seismic wave propagation (attenuation), and site effect. I analyze active faults, seismicity, soil and rock properties, geological cross-sections, the borehole data of measured shear-wave velocity, lithology, amplification factor of each geological unit, geomorphology, topography, and basic rock and surface ground motions. To estimate peak ground acceleration (PGA) at the surface, PGA at the basic rock is multiplied by the amplification parameter of each surface layers. Quaternary soft deposits, representing a highmore » risk due to increasing PGA values at surface, are studied in detail. For a near-zone target earthquake PGA values are compared to intensity at MSK-64 scale for the Absheron peninsula. The amplification factor for the Baku city is assessed and provides estimations for a level of a seismic motion and seismic intensity of the studied area.« less

Arsinoes Chaos Landforms

NASA Technical Reports Server (NTRS)

2004-01-01

23 October 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows light-toned rock outcrops, possibly sedimentary rocks, in the Arsinoes Chaos region east of the Valles Marineris trough system. These rocky materials were once below the martian surface. These features are located near 7.2oS, 27.9oW. The image covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the upper left.

In situ evidence for an ancient aqueous environment at Meridiani Planum, Mars.

PubMed

Squyres, S W; Grotzinger, J P; Arvidson, R E; Bell, J F; Calvin, W; Christensen, P R; Clark, B C; Crisp, J A; Farrand, W H; Herkenhoff, K E; Johnson, J R; Klingelhöfer, G; Knoll, A H; McLennan, S M; McSween, H Y; Morris, R V; Rice, J W; Rieder, R; Soderblom, L A

2004-12-03

Sedimentary rocks at Eagle crater in Meridiani Planum are composed of fine-grained siliciclastic materials derived from weathering of basaltic rocks, sulfate minerals (including magnesium sulfate and jarosite) that constitute several tens of percent of the rock by weight, and hematite. Cross-stratification observed in rock outcrops indicates eolian and aqueous transport. Diagenetic features include hematite-rich concretions and crystal-mold vugs. We interpret the rocks to be a mixture of chemical and siliciclastic sediments with a complex diagenetic history. The environmental conditions that they record include episodic inundation by shallow surface water, evaporation, and desiccation. The geologic record at Meridiani Planum suggests that conditions were suitable for biological activity for a period of time in martian history.

Surface subsidence and collapse in relation to extraction of salt and other soluble evaporites

USGS Publications Warehouse

Ege, John R.

1979-01-01

Extraction of soluble minerals, whether by natural or man-induced processes, can result in localized land-surface subsidence and more rarely sinkhole formation. One process cited by many investigators is that uncontrolled dissolving of salt or other soluble evaporites can create or enlarge underground cavities, thereby increasing the span of the unsupported roof to the strength limit of the overlying rocks. Downwarping results when spans are exceeded, or collapse of the undermined roof leads to upward sloping or chimneying of the overburden rocks. If underground space is available for rock debris to collect, the void can migrate to the surface with the end result being surface subsidence or collapse. In North America natural solution subsidence and collapse features in rocks ranging in age from Silurian to the present are found in evaporite terranes in the Great Plains from Saskatchewan in the north to Texas and New Mexico in the south, in the Great Lakes area, and in the southeastern States. Man-induced subsidence and collapse in evaporites are generally associated with conventional or solution mining, oilfield operations, and reservoir and dam construction, and can be especially hazardous in populated or built-up areas.

Dynamics and internal structure of an Alaskan debris-covered glacier from repeat airborne photogrammetry and surface geophysics

NASA Astrophysics Data System (ADS)

Holt, John; Levy, Joseph; Petersen, Eric; Larsen, Chris; Fahnestock, Mark

2016-04-01

Debris-covered glaciers and rock glaciers encompass a range of compositions and activity, and can be useful paleoclimate indicators. They also respond differently to ongoing climate change than glaciers without a protective cover. Their flow dynamics are not well understood, and their unique surface morphologies, including lobate fronts and arcuate ridges, likely result from viscous flow influenced by a combination of composition, structure, and climatic factors. However, basic connections between flow kinematics and surface morphology have not yet been established, limiting our ability to understand these features. In order to begin to address this problem we have undertaken airborne and surface studies of multiple debris-covered glaciers in Alaska and the western U.S. Sourdough Rock Glacier in the St. Elias Mountains, Alaska, is completely debris-covered and exhibits numerous transverse compressional ridges. Its trunk also exhibits highly regular bumps and swales with a wavelength of ~175 m and amplitudes up to 12 m. In the middle trunk, lineations (boulder trains and furrows) bend around a point roughly 200m from the eastern edge. We acquired five high-resolution airborne surveys of Sourdough Rock Glacier between late 2013 and late 2015 using lidar and photogrammetry to assess annual and seasonal change at the sub-meter level. Differencing the DTMs provides vertical change while feature tracking in orthophotos provide horizontal velocities that indicate meters of annual motion. The flow field is highly correlated with surface features; in particular, compressional ridges in the lower lobe. Stranded, formerly active lobes are also apparent. Surface geophysical studies were undertaken to constrain internal structure and composition using a combination of ground-penetrating radar (GPR) at 50 and 100 MHz in six transects, and time-domain electromagnetic (TDEM) measurements at 47 locations, primarily in an along-flow transect and two cross-flow transects. We infer from the GPR and TDEM data that Sourdough Rock Glacier is 40-50 m thick and consists of a core of relatively pure glacier ice preserved under a 2.5-3 m thick debris mantle. In conclusion, Sourdough is actively flowing, with surface velocities that correlate with surface slope and thickness. A bedrock restriction is inferred from bending flow lines, low surface velocities, and localized thinning of the ice. This comprehensive suite of observations provides the potential to model ice flow and to ultimately link details of the surface morphology to accumulation and rheology through flow kinematics and internal structure.

Analysis

NASA Astrophysics Data System (ADS)

Abdelazeem, Maha; El-Sawy, El-Sawy K.; Gobashy, Mohamed M.

2013-06-01

Ar Rika fault zone constitutes one of the two major parts of the NW-SE Najd fault system (NFS), which is one of the most prominent structural features located in the east of the center of the Arabian Shield, Saudi Arabia. By using Enhancement Thematic Mapper data (ETM+) and Principle Component Analysis (PCA), surface geological characteristics, distribution of rock types, and the different trends of linear features and faults are determined in the study area. First and second order magnetic gradients of the geomagnetic field at the North East of Wadi Ar Rika have been calculated in the frequency domain to map both surface and subsurface lineaments and faults. Lineaments as deduced from previous studies, suggest an extension of the NFS beneath the cover rocks in the study area. In the present study, integration of magnetic gradients and remote sensing analysis that resulted in different valuable derivative maps confirm the subsurface extension of some of the surface features. The 3D Euler deconvolution, the total gradient, and the tilt angle maps have been utilized to determine accurately the distribution of shear zones, the tectonic implications, and the internal structures of the terranes in the Ar Rika quadrangle in three dimensions.

Joint-bounded crescentic scars formed by subglacial clast-bed contact forces: Implications for bedrock failure beneath glaciers

NASA Astrophysics Data System (ADS)

Krabbendam, M.; Bradwell, T.; Everest, J. D.; Eyles, N.

2017-08-01

Glaciers and ice sheets are important agents of bedrock erosion, yet the precise processes of bedrock failure beneath glacier ice are incompletely known. Subglacially formed erosional crescentic markings (crescentic gouges, lunate fractures) on bedrock surfaces occur locally in glaciated areas and comprise a conchoidal fracture dipping down-ice and a steep fracture that faces up-ice. Here we report morphologically distinct crescentic scars that are closely associated with preexisting joints, termed here joint-bounded crescentic scars. These hitherto unreported features are ca. 50-200 mm deep and involve considerably more rock removal than previously described crescentic markings. The joint-bounded crescentic scars were found on abraded rhyolite surfaces recently exposed (< 20 years) beneath a retreating glacier in Iceland, as well as on glacially sculpted Precambrian gneisses in NW Scotland and various Precambrian rocks in Ontario, glaciated during the Late Pleistocene. We suggest a common formation mechanism for these contemporary and relict features, whereby a boulder embedded in basal ice produces a continuously migrating clast-bed contact force as it is dragged over the hard (bedrock) bed. As the ice-embedded boulder approaches a preexisting joint in the bedrock, stress concentrations build up in the bed that exceed the intact rock strength, resulting in conchoidal fracturing and detachment of a crescentic wedge-shaped rock fragment. Subsequent removal of the rock fragment probably involves further fracturing or crushing (comminution) under high contact forces. Formation of joint-bounded crescentic scars is favoured by large boulders at the base of the ice, high basal melting rates, and the presence of preexisting subvertical joints in the bedrock bed. We infer that the relative scarcity of crescentic markings in general on deglaciated surfaces shows that fracturing of intact bedrock below ice is difficult, but that preexisting weaknesses such as joints greatly facilitate rock failure. This implies that models of glacial erosion need to take fracture patterns of bedrock into account.

Interactive Gaussian Graphical Models for Discovering Depth Trends in ChemCam Data

NASA Astrophysics Data System (ADS)

Oyen, D. A.; Komurlu, C.; Lanza, N. L.

2018-04-01

Interactive Gaussian graphical models discover surface compositional features on rocks in ChemCam targets. Our approach visualizes shot-to-shot relationships among LIBS observations, and identifies the wavelengths involved in the trend.

Mud Volcanoes in the Martian Lowlands: Potential Windows to Fluid-Rich Samples from Depth

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Allen, Carlton C.

2009-01-01

The regional setting of the Chryse-Acidalia area augurs well for a fluid-rich subsurface, accumulation of diverse rock types reflecting the wide catchment area, astrobiological prospectivity, and mud volcanism. This latter provides a mechanism for transporting samples from relatively great depth to the surface. Since mud volcanoes are not associated with extreme heat or shock pressures, materials they transport to the surface are likely to be relatively unaltered; thus such materials could contain interpretable remnants of potential martian life (e.g., organic chemical biomarkers, mineral biosignatures, or structural remains) as well as unmetamorphosed rock samples. None of the previous landings on Mars was located in an area with features identified as potential mud volcanoes (Fig. 3), but some of these features may offer targets for future missions aimed at sampling deep fluid-rich strata with potential habitable zones.

Structure, Quaternary history, and general geology of the Corral Canyon area, Los Angeles County, California

USGS Publications Warehouse

Yerkes, R.F.; Wentworth, Carl M.

1965-01-01

The Corral Canyon nuclear power plant site consists of about 305 acres near the mouth of Corral Canyon in the central Santa Monica Mountains; it is located on an east-trending segment of the Pacific Coast between Point Dume and Malibu Canyon, about 28 miles due west of Los Angeles. The Santa Monica Mountains are the southwesternmost mainland part of the Transverse Ranges province, the east-trending features of which transect the otherwise relatively uniform northwesterly trend of the geomorphic and geologic features of coastal California. The south margin of the Transverse Ranges is marked by the Santa Monica fault system, which extends eastward near the 34th parallel for at least 145 miles from near Santa Cruz Island to the San Andreas fault zone. In the central Santa Monica Mountains area the Santa Monica fault system includes the Malibu Coast fault and Malibu Coast zone of deformation on the north; from the south it includes an inferred fault--the Anacapa fault--considered to follow an east-trending topographic escarpmemt on the sea floor about 5 miles south of the Malibu Coast fault. The low-lying terrain south of the fault system, including the Los Angeles basin and the largely submerged Continental Borderland offshore, are dominated by northwest-trending structural features. The Malibu Coat zone is a wide, east-trending band of asymmetrically folded, sheared, and faulted bedrock that extends for more than 20 miles along the north margin of the Santa Monica fault system west of Santa Monica. Near the north margin of the Malibu Coast zone the north-dipping, east-trending Malibu Coast fault juxtaposes unlike, in part contemporaneous sedimentary rock sections; it is inferred to be the near-surface expression of a major crustal boundary between completely unrelated basement rocks. Comparison of contemporaneous structural features and stratigraphic sections (Late Cretaceous to middle Miocene sedimentary, rocks and middle Miocene volcanic and intrusive igneous rocks on the north; middle and upper Miocene sedimentary and middle Miocene volcanic rocks on the south) across the fault demonstrates that neither strike slip of less than 25 miles nor high-angle dip slip can account for this juxtaposition. Instead, the Malibu Coast fault is inferred to have been the locus of large-magnitude, north-south oriented, horizontal shortening (north, or upper, block thrust over south block). This movement occurred at or near the northern boundary of the Continental Borderland, the eastern boundary of which is inferred to be the northwest-trending known-active Newport-Inglewood zone of en echelon right lateral strike-slip faults in the western Los Angeles basin. Local structural features and their relation to regional features, such as those in the Malibu Coast zone, form the basis for the interpretation that the Malibu Coast fault has acted chiefly as a thrust fault. Within the Malibu Coast zone, on both sides of the Malibu Coast fault, structural features in rocks that range in age from Late Cretaceous to late Miocene are remarkably uniform in orientation. The predominant trend of bedding, axial surfaces of numerous asymmetric folds, locally pervasive shear surfaces, and faults is approximately east-west and their predominant dip is northward.. The axes of the folds plunge gently east or west. Evidence from faults and shears within the zone indicates that relative movement on most of these was north (upper) over south. Beyond the Malibu Coast zone to the north and south the rocks entirely lack the asymmetric folds, overturned beds, and the locally abundant shears that characterize the rocks within the zone; these rocks were therefore not subjected to the same deforming forces that existed near the Malibu Coast fault. Movement on the Malibu Coast fault and deformation in the Malibu Coast zone occurred chiefly during the interval between late Miocene and late Pleistocene time. The youngest-known faulting in the Malibu Coast zone is late Pl

Evolution of rock glaciers in Tien Shan, Central Asia, 1971 - 2016 using high-resolution stereo satellite imagery

NASA Astrophysics Data System (ADS)

Bolch, T.; Strel, A.

2017-12-01

The reactions of glaciers to climate change are relatively well known and numerous remote sensing and modelling studies exist. Also debris-covered glaciers are meanwhile relatively well investigated. However, rock glaciers react differently but respective studies are less frequent despite the fact that they also occur in many mountain ranges and can be of significance in relation to hydrology, geomorphology and hazards. Rock glaciers are abundant in Tien Shan and rock glaciers with areas larger 1 km² are common. However, investigating rock glaciers by remote sensing is difficult because their topographical changes are of lower magnitude and less evident than the changes of glaciers. Hence, high resolution imagery and digital terrain models (DTMs) are needed to study these periglacial landforms. We used 1971 Corona KH-4B (resolution 2m), 2012 GeoEye (0.5m) and 2016 Pléiades (0.5m) stereo images to map and investigate the velocity and surface elevation changes of the rock glaciers in the central part of Ile Alatau (Northern Tien Shan) in Kazakhstan. DTMs with a resolution of 5 m were generated and subsequently co-registered. Surface displacements were calculated by feature tracking. Overall we identified almost 50 active rock glaciers covering an area of about 18km², which is more than 40% of the glacier cover of the year 2016 in the investigated valleys. Moraine-type rock glaciers are more common than talus-type rock glaciers. The average surface velocity of the rock glaciers was 0.44 ± 0.30 m a-1 with rates of up to 2m a-1. On average the rock glaciers showed only a slight insignificant surface lowering of 0.04 m a-1 for the period 1971-2012 and of 0.06 m a-1 for 2012-2016. Most of the investigated rock glaciers showed similar distinct patters of change: A surface elevation gain at their fronts indicating an advance, a significant lowering in the upper probably glacier affected parts of the rock glaciers and areas of elevation gain and lowering in between caused by flow patterns and loss of subsurface ice. Analogues results were found for rock glaciers at Ak-Shirak range in Central Tien Shan using similar data. Hence, changes of rock glaciers differ significantly from debris-free and debris-covered glaciers. Work is underway to investigate the rock glaciers more in detail including in-situ measurements using geophysics.

Survival times of meter-sized rock boulders on the surface of airless bodies

NASA Astrophysics Data System (ADS)

Basilevsky, A. T.; Head, J. W.; Horz, F.; Ramsley, K.

2015-11-01

Rock boulders are typical features of the surfaces of many airless bodies, so the possibility of estimating their potential survival times may provide insights into the rates of surface-modification processes. As an opening point of this study we employ estimates of the survival times of meter-sized boulders on the surface of the Moon based on analysis of the spatial density of boulders on the rims of small lunar craters of known absolute age (Basilevsky et al., 2013), and apply them, with necessary corrections, to boulders on other bodies. In this approach the major factor of rock destruction is considered to be impacts of meteorites. However another factor of the rock destruction, thermal fatigue due to day-night cycling, does exist and it was claimed by Delbo et al. (2014) as being more important than meteorite impacts. They concluded this on the basis of known presence of fine material on the surface of small asteroids, claiming that due to extremely low gravity on those bodies, the products of meteorite bombardment should leave these bodies, and thus their presence indicates that the process of thermal fatigue should be much more effective there. Delbo et al. (2014) made laboratory experiments on heating-cooling centimeter-sized samples of chondrites and, applying some assumptions and theoretical modeling concluded that, for example, at 1 AU distance from the Sun, the lifetime of 10 cm rock fragments on asteroids with period of rotation from 2.2 to 6 h should be only ~103 to 104 years (that is ~3.5×106 to 1.5×107 thermal cycles) and the larger the rock, the faster it should be destroyed. In response to those conclusions we assessed the results of earlier laboratory experiments, which show that only a part of comminuted material produced by high-velocity impacts into solid rocks is ejected from the crater while another part is not ejected but stays exposed on the target surface and is present in its subsurface. This means that the presence of granulometrically fine material on the surface of small asteroids does not prove the predominance of thermal stresses over rupture by meteorite impacts as a factor in the comminution of the surface material. We then analyzed images of lunar rocks of decimeters- to meters-size whose lunar surface exposure ages were radiometrically dated. This analysis shows that the presence of the fragment on the lunar surface for a time period 26-400 Ma (that is, ~3×108 to 5×109 day-night thermal cycles) did not lead to the formation of any features conclusively supporting rock destruction by thermal cycles. In turn, this means that on the lunar surface as well as on the surface of other bodies at 1 AU and further from the Sun, the destruction of rocks by thermal fatigue is secondary compared to rock rupture by the meteorite impacts. The possible implications of the difference in environments on fast spinning asteroids and on the Moon require additional analysis Then utilizing the entire catalog of inner solar system minor planet orbits out to Jupiter as a proxy for the distribution of potential impactors throughout the inner solar system, we calculated the meteorite flux and impact velocities for a number of airless bodies to use them for estimates of survival times of rock boulders on their surfaces (normalized to those for lunar boulders). We found that if the average survival time for meter-size rock boulders on the surface of the Moon is 1, then considering rupture by the meteorite impacts as the major process of rock destruction, for Phobos it is ~0.8, for Deimos ~0.7, for asteroid Itokawa ~1, for Eros ~0.3, for Vesta and Ceres ~0.03 and for the average of the first 150 Trojans discovered is ~12.5. Implications of these findings are that on the surfaces of Vesta and Ceres, compared to the Moon, the regolith layer should generally have a larger thickness and higher maturity, while small craters with rocky ejecta are rare. On the typical Trojans, where impact flux is closer to that on the Moon, but the impact velocities are by factor 4 lower, the situation should be the opposite: thinner layer of regolith, lower maturity and a larger percentage of small craters with rocky ejecta. These predictions and observations can be tested with future robotic and human exploration of the Moon and small bodies.

Analysis and interpretation of marine/continental terraces in the central coast of Asturias (NW Spain

NASA Astrophysics Data System (ADS)

María Díaz-Díaz, Luis; Flor-Blanco, Germán; López-Fernández, Carlos; Luis, Pando

2016-04-01

This study presents the geographical distribution and topographical features analysis of several marine/continental terraces located in a sector between Nalón estuary and Cape Peñas region (central coast of Asturias, N Spain). Significant flat raised surfaces appear as outstanding landscape features of the Cantabrian coast. They exhibit north facing low gradient slopes (< 5°) until the cliff shoreline and the borders are defined by the pre-littoral mountains to the south. These surfaces have a width of no more than 5 km and occasionally may be thinly mantled by many alluvial clastic deposits, very scarce aeolian sands and gravel and/or sand beach deposits. Several studies have shown the importance of these terraces, which are recognized by the preservation of a variable number of levels of flat raised and staggered irregularly surfaces. These surfaces have been used to quantify rates of rock uplift processes. GIS and quantitative analysis of the relief are applied to the recognition and delineation of terraces. Altimetry information comes from the Digital Elevation Model (DEM) Digital (cell size 5 m). The use of slope Digital Slopes Model (DSM) combined with digital lithology layers and hypsometric method allowed us to identify two main new surfaces at altitudes ranging from 75 to 135 m and 85 to 180 m respectively. Levels of surfaces recognized in previous studies may be correlated with this elevations. They are separated by a huge geologic structure (Ventaniella Fault). Thus, two NW-SE direction landward edge of terrace (shoreline angle) was identified. This feature enables correlate these surface or the old knickpoint (foot of the slope) if the terrace has a continental origin. Initial morphology of these terraces has been modified by landscape erosion much more those developed on limestones. Therefore, just a few areas are preserved where flat surfaces are developed in Paleozoic materials (NO) better in siliciclastic rocks. The remaining areas are modelled in the lowest resistance lithology like Permo-triassic rocks. Therefore, using classic techniques as fieldwork and phointerpretation is not discriminatory.

Mars Pathfinder Landing Site: Evidence for a Change in Wind Regime and Climate from Lander and Orbiter Data

NASA Technical Reports Server (NTRS)

Greeley, R.; Kraft, M. D.; Kuzmin, R. O.; Bridges, N. T.

1999-01-01

Surface features related to the wind are observed in data from the Mars Pathfinder lander and from orbit by the Viking Orbiter and Mars Global Surveyor missions. Features seen from the surface include wind tails associated with small rocks, barchanoid duneforms, ripplelike patterns, and ventifact flutes cut into some rocks. Features seen from orbit include wind tails associated with impact craters, ridges inferred to be duneforms, and modified crater rims interpreted to have been eroded and mantled by windblown material. The orientations of these features show two prevailing directions, one inferred to represent winds from the northeast which is consistent with strongest winds predicted by a general circulation model to occur during the Martian northern winter under current conditions, and a second wind pattern oriented approx. 90 degrees to the first. This latter wind could be from the W-NW or from the E-SE and was responsible for cutting the ventifacts and modifying the crater rims. The two wind regimes could reflect a change in climate related to Mars' obliquity or some other, unknown factor. Regardless of the cause, the MPF area has been subjected to a complex pattern of winds and supply of small particles, in which the original surface formed by sedimentary processes from Tiu and Ares Vallis events has been modified by repeated burial and exhumation.

Features of the Earth surface deformations in the Kamchatka peninsula and their relation to geoacoustic emission

NASA Astrophysics Data System (ADS)

Larionov, I. A.; Marapulets, Y. V.; Shevtsov, B. M.

2014-12-01

The paper presents the results of investigations of deformation processes in the near-surface sedimentary rocks, which have been carried out in a seismically active region of the Kamchatka peninsula since 2007. The peculiarity of the experiments on registration of geodeformations is the application of a laser strainmeter-interferometer constructed according to the Michelson interferometer scheme. Besides rock deformations, geoacoustic emission in the frequency range from several hertz to the first tens of kilohertz is under investigation. Piezoceramic hydrophones installed in artificial water reservoirs are applied. It is shown that periods of primary rock compression and tension with a duration of up to several months are distinguished in the geodeformation process at the observation site. During the direction change in the deformations, when the geodeformation process rate grows, an increase in geoacoustic radiation is observed.

Surface clay formation during short-term warmer and wetter conditions on a largely cold ancient Mars

NASA Astrophysics Data System (ADS)

Bishop, Janice L.; Fairén, Alberto G.; Michalski, Joseph R.; Gago-Duport, Luis; Baker, Leslie L.; Velbel, Michael A.; Gross, Christoph; Rampe, Elizabeth B.

2018-03-01

The ancient rock record for Mars has long been at odds with climate modelling. The presence of valley networks, dendritic channels and deltas on ancient terrains points towards running water and fluvial erosion on early Mars1, but climate modelling indicates that long-term warm conditions were not sustainable2. Widespread phyllosilicates and other aqueous minerals on the Martian surface3-6 provide additional evidence that an early wet Martian climate resulted in surface weathering. Some of these phyllosilicates formed in subsurface crustal environments5, with no association with the Martian climate, while other phyllosilicate-rich outcrops exhibit layered morphologies and broad stratigraphies7 consistent with surface formation. Here, we develop a new geochemical model for early Mars to explain the formation of these clay-bearing rocks in warm and wet surface locations. We propose that sporadic, short-term warm and wet environments during a generally cold early Mars enabled phyllosilicate formation without requiring long-term warm and wet conditions. We conclude that Mg-rich clay-bearing rocks with lateral variations in mixed Fe/Mg smectite, chlorite, talc, serpentine and zeolite occurrences formed in subsurface hydrothermal environments, whereas dioctahedral (Al/Fe3+-rich) smectite and widespread vertical horizonation of Fe/Mg smectites, clay assemblages and sulphates formed in variable aqueous environments on the surface of Mars. Our model for aluminosilicate formation on Mars is consistent with the observed geological features, diversity of aqueous mineralogies in ancient surface rocks and state-of-the-art palaeoclimate scenarios.

Morphological features of Miocene submarine coherent lavas from the ``Green Tuff'' basins: examples from basaltic and andesitic rocks from the Shimokita Peninsula, northern Japan

NASA Astrophysics Data System (ADS)

Yamagishi, Hiromitsu

1991-04-01

Basaltic and andesitic volcanic rocks of Miocene age exposed in the Shimokita Peninsula, northern Japan, illustrate morphological features of typical submarine coherent lavas of the “Green Tuff” basins in Japan. They are pillow lobes with surface structures, such as ropey wrinkles, corrugations, spreading cracks and tensional cracks, and lava lobes composed of a lithic core and glassy border zone or rim with an in-situ breccia zone grading outward into surrounding hyaloclastite. In addition they include massive lavas with columnar joints, and jointed dykes. The submarine coherent lavas and dykes are commonly associated with hyaloclastic breccias, such as pillow fragment breccia and angular fragment breccia. The descriptions of the Miocene volcanic rocks in the Shimokita Peninsula provide good criteria for recognition of submarine coherent lavas of basalt and andesite.

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2010-08-11

This is a Hygrochron sensor. Sensors were buried at different depths, to see how the temperature and moisture levels in the ground changed close to and farther from the surface. Special permission from the National Park Service is needed to dig at Racetrack Playa. Photo credit: NASA/GSFC/Maggie McAdam To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Impact Cratering Calculations

NASA Technical Reports Server (NTRS)

Ahrens, Thomas J.

2002-01-01

Many Martian craters are surrounded by ejecta blankets which appear to have been fluidized forming lobate and layered deposits terminated by one or more continuous distal scarps, or ramparts. One of the first hypotheses for the formation of so-called rampart ejecta features was shock-melting of subsurface ice, entrainment of liquid water into the ejecta blanket, and subsequent fluidized flow. Our work quantifies this concept. Rampart ejecta found on all but the youngest volcanic and polar regions, and the different rampart ejecta morphologies are correlated with crater size and terrain. In addition, the minimum diameter of craters with rampart features decreases with increasing latitude indicating that ice laden crust resides closer to the surface as one goes poleward on Mars. Our second goal in was to determine what strength model(s) reproduce the faults and complex features found in large scale gravity driven craters. Collapse features found in large scale craters require that the rock strength weaken as a result of the shock processing of rock and the later cratering shear flows. In addition to the presence of molten silicate in the intensely shocked region, the presence of water, either ambient, or the result of shock melting of ice weakens rock. There are several other mechanisms for the reduction of strength in geologic materials including dynamic tensile and shear induced fracturing. Fracturing is a mechanism for large reductions in strength. We found that by incorporating damage into the models that we could in a single integrated impact calculation, starting in the atmosphere produce final crater profiles having the major features found in the field measurements (central uplifts, inner ring, terracing and faulting). This was accomplished with undamaged surface strengths (0.1 GPa) and in depth strengths (1.0 GPa).

Rock Abrasion on Mars: Clues from the Pathfinder and Viking Landing Sites

NASA Technical Reports Server (NTRS)

Bridges, N. T.; Parker, T. J.; Kramer, G. M.

2000-01-01

A significant discovery of the Mars Pathfinder (MPF) mission was that many rocks exhibit characteristics of ventifacts, rocks that have been sculpted by saltating particles. Diagnostic features identifying the rocks as ventifacts am elongated pits, flutes, and grooves (collectively referred to as "flutes" unless noted otherwise). Faceted rocks or rock portions, circular pits, rills, and possibly polished rock surfaces are also seen and could be due, to aeolian abrasion. Many of these features were initially identified in rover images, where spatial resolution generally exceeded that of the IMP (Imager for Mars Pathfinder) camera. These images had two major limitations: 1) Only a limited number of rocks were viewed by the rover, biasing flute statistics; and 2) The higher resolution obtained by the rover images and the lack of such pictures at the Viking landing sites hampered comparisons of rock morphologies between the Pathfinder and Viking sites. To avoid this problem, rock morphology and ventifact statistics have been examined using new "super-resolution" IMP and Viking Lander images. Analyses of these images show that: 1) Flutes are seen on about 50% or more of the rocks in the near field at the MPF site; 2) The orientation of these flutes is similar to that for flutes identified in rover images; and 3) Ventifacts are significantly more abundant at the Pathfinder landing site than at the two Viking Landing sites, where rocks have undergone only a limited amount of aeolian abrasion. This is most likely due to the ruggedness of the Pathfinder site and a greater supply of abrading particles available shortly after the Arcs and Tiu Valles outflow channel floods.

Distribution of rock fragments and their effects on hillslope soil erosion in purple soil, China

NASA Astrophysics Data System (ADS)

Wang, Xiaoyan

2017-04-01

Purple soil is widely distributed in Sichuan Basin and Three Gorges Reservoir Area. Purple soil region is abundant in soil fertility and hydrothermal resources, playing an important role in the agricultural development of China. Soil erosion has long been recognized as a major environmental problem in the purple soil region where the population is large and slope farming is commonly practiced, and rainstorm is numerous. The existence of rock fragments is one of the most important characteristics of purple soil. Rock fragments at the soil surface or in the soil layer affect soil erosion processes by water in various direct and indirect ways, thus the erosion processes of soil containing rock fragments have unique features. Against the severe soil degradation by erosion of purple soil slope, carrying out the research about the characteristics of purple soil containing rock fragments and understanding the influence of rock fragments on soil erosion processes have important significance, which would promote the rational utilization of purple soil slope land resources and accurate prediction of purple soil loss. Therefore, the aims of this study were to investigate the distribution of rock fragments in purple soil slope and the impact of rock fragment content on soil physical properties and soil erosion. First, field sampling methods were used to survey the spatial variability of rock fragments in soil profiles and along slope and the physical properties of soils containing rock fragments. Secondly, indoor simulated rainfall experiments were used to exam the effect of rock fragments in the soil layer on soil erosion processes and the relationships between rainfall infiltration, change of surface flow velocity, surface runoff volume and sediment on one hand, and rock fragment content (Rv, 0% 30%, which was determined according the results of field investigation for rock fragment distribution) on the other were investigated. Thirdly, systematic analysis about the influence of rock fragment cover on purple soil slope erosion process were carried on, under different conditions with two kind of rock fragment positions (resting on soil surface and embedded into top soil layer), varied rock fragment coverage (Rc, 0% 40%), two kind of soils with textural porosity or structural porosity, and three kind of rainfall intensities (I, 1 mm/min, 1.5 mm/min and 2 mm/min). Simulated rainfall experiments in situ plots in the field, combined with simulated rainfall experiments in soil pans indoor, were used. The main conclusions of this dissertation are as following: 1. The spatial distribution characteristics of rock fragments in purple soil slope and its effects on the soil physical properties were clarified basically. 2. The mechanism of influence of rock fragments within top soil layer on soil erosion processes was understood and a threshold of rock fragment content on the infiltration was figured out. 3. The relationships between surface rock fragment cover and hillslope soil erosion in purple soil under different conditions with varied rock fragment positions, soil structures and rainfall intensities were obtained and the soil and water conservation function of surface rock fragment cover on reducing soil loss was affirmed.

Interesting Features in Spirit's Uphill View

NASA Technical Reports Server (NTRS)

2004-01-01

Planetary scientists got excited when they saw this imagery coming in from NASA's Mars Exploration Rover Spirit because they could see hints of rock strata and other interesting geologic features ahead. In the middle of this image, from upper left to the lower right, lies a trough that resembles a small ravine. To the right of that and a little way up the hill, beyond a rock-strewn surface, sits a small rounded ridge. Fine horizontal streaks, just perceptible in this image, suggest possible layering in the bedrock. Above that are rock features that appear to drape across the slopes. Scientists are discussing whether to take the rover closer or select other interesting targets for further study. This view looks eastward from the 'West Spur' of the 'Columbia Hills,' where Spirit has been conducting scientific investigations. It is a mosaic of several frames Spirit took with its panoramic camera on the rover's 229th martian day, or sol, (Aug. 24, 2004). The field of view is 48 degrees from left to right. The image is presented in a cylindrical projection with geometrical seam correction.

The application of automatic recognition techniques in the Apollo 9 SO-65 experiment

NASA Technical Reports Server (NTRS)

Macdonald, R. B.

1970-01-01

A synoptic feature analysis is reported on Apollo 9 remote earth surface photographs that uses the methods of statistical pattern recognition to classify density points and clusterings in digital conversion of optical data. A computer derived geological map of a geological test site indicates that geological features of the range are separable, but that specific rock types are not identifiable.

Using Crater Counts to Constrain Erosion Rates on Mars: Implications for the Global Dust Cycle, Sedimentary Rock Erosion and Organic Matter Preservation

NASA Astrophysics Data System (ADS)

Mayer, D. P.; Kite, E. S.

2016-12-01

Sandblasting, aeolian infilling, and wind deflation all obliterate impact craters on Mars, complicating the use of crater counts for chronology, particularly on sedimentary rock surfaces. However, crater counts on sedimentary rocks can be exploited to constrain wind erosion rates. Relatively small, shallow craters are preferentially obliterated as a landscape undergoes erosion, so the size-frequency distribution of impact craters in a landscape undergoing steady exhumation will develop a shallower power-law slope than a simple production function. Estimating erosion rates is important for several reasons: (1) Wind erosion is a source of mass for the global dust cycle, so the global dust reservoir will disproportionately sample fast-eroding regions; (2) The pace and pattern of recent wind erosion is a sorely-needed constraint on models of the sculpting of Mars' sedimentary-rock mounds; (3) Near-surface complex organic matter on Mars is destroyed by radiation in <108 years, so high rates of surface exhumation are required for preservation of near-surface organic matter. We use crater counts from 18 HiRISE images over sedimentary rock deposits as the basis for estimating erosion rates. Each image was counted by ≥3 analysts and only features agreed on by ≥2 analysts were included in the erosion rate estimation. Erosion rates range from 0.1-0.2 {μ }m/yr across all images. These rates represent an upper limit on surface erosion by landscape lowering. At the conference we will discuss the within and between-image variability of erosion rates and their implications for recent geological processes on Mars.

Thermal-infrared spectral observations of geologic materials in emission

NASA Technical Reports Server (NTRS)

Christensen, Philip R.; Luth, Sharon J.

1987-01-01

The thermal-infrared spectra of geologic materials in emission were studied using the prototype Thermal Emission Spectrometer (TES). A variety of of processes and surface modifications that may influence or alter the spectra of primary rock materials were studied. It was confirmed that thermal emission spectra contain the same absorption features as those observed in transmission and reflection spectra. It was confirmed that the TES instrument can be used to obtain relevant spectra for analysis of rock and mineral composition.

Two years at Meridiani Planum: Results from the opportunity rover

USGS Publications Warehouse

Squyres, S. W.; Knoll, A.H.; Arvidson, R. E.; Clark, B. C.; Grotzinger, J.P.; Jolliff, B.L.; McLennan, S.M.; Tosca, N.; Bell, J.F.; Calvin, W.M.; Farrand, W. H.; Glotch, T.D.; Golombek, M.P.; Herkenhoff, K. E.; Johnson, J. R.; Klingelhofer, G.; McSween, H.Y.; Yen, A. S.

2006-01-01

The Mars Exploration Rover Opportunity has spent more than 2 years exploring Meridiani Planum, traveling ???8 kilometers and detecting features that reveal ancient environmental conditions. These include well-developed festoon (trough) cross-lamination formed in flowing liquid water, strata with smaller and more abundant hematite-rich concretions than those seen previously, possible relict "hopper crystals" that might reflect the formation of halite, thick weathering rinds on rock surfaces, resistant fracture fills, and networks of polygonal fractures likely caused by dehydration of sulfate salts. Chemical variations with depth show that the siliciclastic fraction of outcrop rock has undergone substantial chemical alteration from a precursor basaltic composition. Observations from microscopic to orbital scales indicate that ancient Meridiani once had abundant acidic groundwater, arid and oxidizing surface conditions, and occasional liquid flow on the surface.

A new 3-D thin-skinned rock glacier model based on helicopter GPR results from the Swiss Alps

NASA Astrophysics Data System (ADS)

Merz, Kaspar; Green, Alan G.; Buchli, Thomas; Springman, Sarah M.; Maurer, Hansruedi

2015-06-01

Mountainous locations and steep rugged surfaces covered by boulders and other loose debris are the main reasons why rock glaciers are among the most challenging geological features to investigate using ground-based geophysical methods. Consequently, geophysical surveys of rock glaciers have only ever involved recording data along sparse lines. To address this issue, we acquired quasi-3-D ground-penetrating radar (GPR) data across a rock glacier in the Swiss Alps using a helicopter-mounted system. Our interpretation of the derived GPR images constrained by borehole information results in a novel "thin-skinned" rock glacier model that explains a concentration of deformation across a principal shear zone (décollement) and faults across which rock glacier lobes are juxtaposed. The new model may be applicable to many rock glaciers worldwide. We suggest that the helicopter GPR method may be useful for 3-D surveying numerous other difficult-to-access mountainous terrains.

A visual analytical approach to rock art panel condition assessment

NASA Astrophysics Data System (ADS)

Vogt, Brandon J.

Rock art is a term for pecked, scratched, or painted symbols found on rock surfaces, most typically joint faces called rock art panels. Because rock art exists on rock at the atmosphere interface, it is highly susceptible to the destructive processes of weathering. Thus, rock weathering scientists, including those that study both natural and cultural surfaces, play a key role towards understanding rock art longevity. The mapping of weathering forms on rock art panels serves as a basis from which to assess overall panel instability. This work examines fissures, case hardened surfaces, crumbly disintegration, and lichen. Knowledge of instability, as measured through these and other weathering forms, provides integral information to land managers and archaeological conservators required to prioritize panels for remedial action. The work is divided into five chapters, three of which are going to be submitted as a peer-reviewed journal manuscript. The second chapter, written as a manuscript for International Newsletter on Rock Art, describes a specific set of criteria that lead to the development of a mapping tool for weathering forms, called 'mapping weathering forms in three dimensions' (MapWeF). The third chapter, written as a manuscript for Remote Sensing of Environment, presents the methodology used to develop MapWeF. The chapter incorporates terrestrial laser scanning, a geographic information system (GIS), geovisualization, image analysis, and exploratory spatial data analysis (ESDA) to identify, map, and quantify weathering features known to cause instability on rock art panels. The methodology implemented in the third chapter satisfies the criteria described in Chapter Two. In the fourth chapter, prepared as a manuscript for Geomorphology, MapWeF is applied to a site management case study, focusing on a region---southeastern Colorado---with notoriously weak and endangered sandstone rock art panels. The final conclusions chapter describes contributions of the work to GIScience and rock weathering, and discusses how MapWeF, as a diagnostic tool, fits into a larger national vision by linking existing rock art stability characterizations to cultural resource management-related conservation action.

Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska

NASA Astrophysics Data System (ADS)

Darrow, Margaret M.; Gyswyt, Nora L.; Simpson, Jocelyn M.; Daanen, Ronald P.; Hubbard, Trent D.

2016-05-01

Frozen debris lobes (FDLs) are elongated, lobate permafrost features that mostly move through shear in zones near their bases. We present a comprehensive overview of eight FDLs within the Dalton Highway corridor (southern Brooks Range, Alaska), including their catchment geology and rock strengths, lobe soil characteristics, surface movement measurements collected between 2012 and 2015, and analysis of historic and modern imagery from 1955 to 2014. Field mapping and rock strength data indicate that the metasedimentary and metavolcanic bedrock forming the majority of the lobe catchments has very low to medium strength and is heavily fractured, thus easily contributing to FDL formation. The eight investigated FDLs consist of platy rocks typical of their catchments, organic debris, and an ice-poor soil matrix; massive ice, however, is present within FDLs as infiltration ice, concentrated within cracks open to the surface. Exposure of infiltration ice in retrogressive thaw slumps (RTSs) and associated debris flows leads to increased movement and various stages of destabilization, resulting in morphological differences among the lobes. Analysis of historic imagery indicates that movement of the eight investigated FDLs has been asynchronous over the study period, and since 1955, there has been an overall increase in movement rates of the investigated FDLs. The formation of surface features, such as cracks, scarps, and RTSs, suggests that the increased movement rates correlate to general instability, and even at their current distances, FDLs are impacting infrastructure through increased sediment mobilization. FDL-A is the largest of the investigated FDLs. As of August 2015, FDL-A was 39.2 m from the toe of the Dalton Highway embankment. Based on its current distance and rate of movement, we predict that FDL-A will reach the Dalton Highway alignment by 2023.

Hammersley Range, northern Western Australia

NASA Image and Video Library

1990-04-29

The oval shaped basin of the sedimentary rocks of the Hammersley Range, northern Western Australia (23.0S, 119.0E) dominates the center of this near nadir view. The Fortescue River is the remarkably straight, fault controlled feature bordering the Hammersley on the north. Sand dunes are the main surface features in the northeast and southwest. Many dry lakebeds can be seen to the east as light grey colored patches along the watercourses.

Geologic and anthropogenic factors influencing karst development in the Frederick region of Maryland

USGS Publications Warehouse

Brezinski, D.K.

2007-01-01

Karst features pervade the outcrop belts of Triassic, Ordovician, and Cambrian rocks in the Frederick Valley region of Maryland's western Piedmont. Detailed stratigraphic analysis and geologic and karst mapping demonstrate that individual stratigraphic units have differing susceptibilities of karst feature creation. Although the Triassic Leesburg Member of the Bull Run Formation and Rocky Springs Station Member of the Cambrian Frederick Formation have many surface depressions within their outcrop belts, the Lime Kiln Member of the Frederick Formation and the Ceresville, Fountain Rock, and Woodsboro members of the Ordovician Grove Formation have the greatest potential for development of catastrophic collapse sinkholes. Although these four members have the highest relative susceptibility, human activity can increase the potential for sinkhole activation in all units. Rerouting of surface drainage patterns, unlined drainage, and storm-water management areas and removal of significant overburden deposits significantly increase sinkhole development, but mainly, these units are inherently more susceptible to begin with. Copyright ?? 2007. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.

Distribution and features of landslides induced by the 2008 Wengchuan Earthquake, Sichuan, China

NASA Astrophysics Data System (ADS)

Chigira, M.; Xiyong, W.; Inokuchi, T.; Gonghui, W.

2009-04-01

2008 Sichuan earthquake with a magnitude of Mw 7.9 induced numerous mass movements around the fault surface ruptures of which maximum separations we observed were 3.6 m vertical and 1.5 m horizontal (right lateral). The affected area was mountainous areas with elevations from 1000 m to 4500 m on the west of the Sichuan Basin. The NE-trending Longmenshan fault zone runs along the boundary between the mountains on the west and the Sichuan basin (He and Tsukuda, 2003), of which Yinghsiuwan-Beichuan fault was the main fault that generated the 2008 earthquake (Xu, 2008). The basement rocks of the mountainous areas range from Precambrian to Cretaceous in age. They are basaltic rocks, granite, phyllite, dolostone, limestone, alternating beds of sandstone and shale, etc. There were several types of landslides ranging from small, shallow rockslide, rockfall, debris slide, deep rockslide, and debris flows. Shallow rockslide, rock fall, and debris slide were most common and occurred on convex slopes or ridge tops. When we approached the epicentral area, first appearing landslides were of this type and the most conspicuous was a failure of isolated ridge-tops, where earthquake shaking would be amplified. As for rock types, slopes of granitic rocks, hornfels, and carbonate rocks failed in wide areas to the most. They are generally hard and their fragments apparently collided and repelled to each other and detached from the slopes. Alternating beds of sandstone and mudstone failed on many slopes near the fault ruptures, including Yinghsiuwan near the epicenter. Many rockfalls occurred on cliffs, which had taluses on their feet. The fallen rocks tumbled down and mostly stopped within the talus surfaces, which is quite reasonable because taluses generally develop by this kind of processes. Many rockslides occurred on slopes of carbonate rocks, in which dolostone or dolomitic limestone prevails. Deep-seated rockslide occurred on outfacing slopes and shallow rockslide and rockfall occurred on infacing slopes. Infacing slopes generally are steeper than outfacing slopes and hence surface rocks on infacing slopes tend to be loosened by gravity. Detachment surfaces of carbonate rocks are generally not smooth surfaces but are rough surfaces with dimple-like depressions, which are made by dissolution of these rocks. This feature is one of the most important causes to induce landslide in carbonate rocks. Many gravitational deformations were observed on phyllite slopes. Landslides on the west of Beichuan city is probably of weathered phyllite, which had been preceded by gravitational deformation beforehand. Taochishan landslide in Beichuan occurred on probable outfacing slope of phyllite. The Formosat II images on Google earth indicated that this landslide was also preceded by gravitational deformation, which appeared as spur-crossing depressions with upslope-convex traces on plan. Satellite images indicated that some landslides had long lobate forms, suggesting that they were flow. One of them was Shechadientsu landslide 34 km northeast of Dujiangyan, occurring across the probable earthquake fault rupture. It was 1.5 km long with a maximum width of 250 m and an apparent friction angle of 22°. The top of this landslide area was a steep cliff of Precambrian granite, which failed to go down a small valley. The volume of the slope failure was estimated much less than the volume of the deposit. The small valley had sporadic patches of bedrock consisting of alternating beds of sandstone and mudstone of Triassic in age. The bedrock was covered by bluish grey, clayey, water-saturated debris, which was not disturbed and in turn covered by water-saturated brownish debris with rubbles. The landslide deposits had wrinkles on the surface and streaks of same color rock fragments. In addition, cross section near the distal part had clearly defined reverse grading, in which larger rubbles with a maximum diameter of 5 m concentrated at the surface part. These characteristics strongly suggest that valley-fill sediments mobilized by the earthquake and flowed down the valley, getting higher at the outer side of the valley bent. The largest landslide with an estimated volume of 1 billion m3 occurred on an outfacing carbonate rock slope, which had been preceded by gravitational deformation appearing as a ridge-top depression. The second largest one occurred on a smooth outfacing slope that had been undercut.

Laboratory Reflectance Spectra in the Middle-infrared: Effects of Grain Size on Spectral Features

NASA Astrophysics Data System (ADS)

Le Bras, A.; Erard, S.; Fulchignoni, M.

2000-10-01

Since spectral mineral features are sensitive to surface parameters, interpretation of remote-sensing asteroids spectra in terms of mineral composition is not easy nor unique, and laboratory spectra are needed in order to understand the influence of each parameter. We developped an experimental program at IAS, using the 2.5-120 microns interferometer spectrometer, to study the influence of surface parameters on mineral features. We present here the results obtained variing the grain size. We studied grain size effects with two types of terrestrial rocks: anorthosite (bright) and basalte (dark) in the 2-40 microns range. We observed variations of the spectral contrast with grain size, shifts in wavelengths and variations of the intensity of some characteristic spectral features, and appearence of transparency features at wavelengths longer than 8 microns.

Integrated system for investigating sub-surface features of a rock formation

DOEpatents

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

2015-08-18

A system for investigating non-linear properties of a rock formation around a borehole is provided. The system includes a first sub-system configured to perform data acquisition, control and recording of data; a second subsystem in communication with the first sub-system and configured to perform non-linearity and velocity preliminary imaging; a third subsystem in communication with the first subsystem and configured to emit controlled acoustic broadcasts and receive acoustic energy; a fourth subsystem in communication with the first subsystem and the third subsystem and configured to generate a source signal directed towards the rock formation; and a fifth subsystem in communication with the third subsystem and the fourth subsystem and configured to perform detection of signals representative of the non-linear properties of the rock formation.

Petrography of shock features in the 1953 Manson 2-A drill core

NASA Technical Reports Server (NTRS)

Short, N. M.; Gold, D. P.

1993-01-01

Drilling of Nx core in late 1953 into an anomalous zone of disturbed rocks northwest of Manson, Iowa disclosed presence of extensive breccias including crystalline rocks brought to the surface from depths of 4 km or more. Hole 2-A penetrated breccias dominated by leucocratic igneous and metamorphic lithologies, later interpreted to be part of a general ringed peak complex within a 35 km wide impact structure produced about 65 Ma ago. Proof of this origin was given in 1966 by NMS through recognition of shock metamorphic features in 2-A materials during a cursory examination of samples provided by R.A. Hoppin, University of Iowa. A detailed study of this material now underway has revealed that most breccia clasts in 2-A show abundant and varied evidence of shock damage, including extensive planar deformation features (PDF) in quartz, K-feldspar, plagioclase, and a pyroxene and varying degrees of isotropization and incipient melting in feldspars.

Mapping snow depth in complex alpine terrain with close range aerial imagery - estimating the spatial uncertainties of repeat autonomous aerial surveys over an active rock glacier

NASA Astrophysics Data System (ADS)

Goetz, Jason; Marcer, Marco; Bodin, Xavier; Brenning, Alexander

2017-04-01

Snow depth mapping in open areas using close range aerial imagery is just one of the many cases where developments in structure-from-motion and multi-view-stereo (SfM-MVS) 3D reconstruction techniques have been applied for geosciences - and with good reason. Our ability to increase the spatial resolution and frequency of observations may allow us to improve our understanding of how snow depth distribution varies through space and time. However, to ensure accurate snow depth observations from close range sensing we must adequately characterize the uncertainty related to our measurement techniques. In this study, we explore the spatial uncertainties of snow elevation models for estimation of snow depth in a complex alpine terrain from close range aerial imagery. We accomplish this by conducting repeat autonomous aerial surveys over a snow-covered active-rock glacier located in the French Alps. The imagery obtained from each flight of an unmanned aerial vehicle (UAV) is used to create an individual digital elevation model (DEM) of the snow surface. As result, we obtain multiple DEMs of the snow surface for the same site. These DEMs are obtained from processing the imagery with the photogrammetry software Agisoft Photoscan. The elevation models are also georeferenced within Photoscan using the geotagged imagery from an onboard GNSS in combination with ground targets placed around the rock glacier, which have been surveyed with highly accurate RTK-GNSS equipment. The random error associated with multi-temporal DEMs of the snow surface is estimated from the repeat aerial survey data. The multiple flights are designed to follow the same flight path and altitude above the ground to simulate the optimal conditions of repeat survey of the site, and thus try to estimate the maximum precision associated with our snow-elevation measurement technique. The bias of the DEMs is assessed with RTK-GNSS survey observations of the snow surface elevation of the area on and surrounding the rock glacier. Additionally, one of the challenges with processing snow cover imagery with SfM-MVS is dealing with the general homogeneity of the surface, which makes is difficult for automated-feature detection algorithms to identify key features for point matching. This challenge depends on the snow cover surface conditions, such as scale, lighting conditions (high vs. low contrast), and availability of snow-free features within a scene, among others. We attempt to explore this aspect by spatial modelling the factors influencing the precision and bias of the DEMs from image, flight, and terrain attributes.

Solution pans and linear sand bedforms on the bare-rock limestone shelf of the Campeche Bank, Yucatán Peninsula, Mexico

NASA Astrophysics Data System (ADS)

Goff, John A.; Gulick, Sean P. S.; Cruz, Ligia Perez; Stewart, Heather A.; Davis, Marcy; Duncan, Dan; Saustrup, Steffen; Sanford, Jason; Fucugauchi, Jaime Urrutia

2016-04-01

A high-resolution, near-surface geophysical survey was conducted in 2013 on the Campeche Bank, a carbonate platform offshore of Yucatán, Mexico, to provide a hazard assessment for future scientific drilling into the Chicxulub impact crater. It also provided an opportunity to obtain detailed information on the seafloor morphology and shallow stratigraphy of this understudied region. The seafloor exhibited two morphologies: (1) small-scale (<2 m) bare-rock karstic features, and (2) thin (<1 m) linear sand accumulations overlying the bedrock. Solution pans, circular to oblong depressions featured flat bottoms and steep sides, were the dominant karstic features; they are known to form subaerially by the pooling of rainwater and dissolution of carbonate. Observed pans were 10-50 cm deep and generally 1-8 m wide, but occasionally reach 15 m, significantly larger than any solution pan observed on land (maximum 6 m). These features likely grew over the course of many 10's of thousands of years in an arid environment while subaerially exposed during lowered sea levels. Surface sands are organized into linear bedforms oriented NE-SW, 10's to 100's meters wide, and kilometers long. These features are identified as sand ribbons (longitudinal bedforms), and contained asymmetric secondary transverse bedforms that indicate NE-directed flow. This orientation is incompatible with the prevalent westward current direction; we hypothesize that these features are storm-generated.

A new method for automated discontinuity trace mapping on rock mass 3D surface model

NASA Astrophysics Data System (ADS)

Li, Xiaojun; Chen, Jianqin; Zhu, Hehua

2016-04-01

This paper presents an automated discontinuity trace mapping method on a 3D surface model of rock mass. Feature points of discontinuity traces are first detected using the Normal Tensor Voting Theory, which is robust to noisy point cloud data. Discontinuity traces are then extracted from feature points in four steps: (1) trace feature point grouping, (2) trace segment growth, (3) trace segment connection, and (4) redundant trace segment removal. A sensitivity analysis is conducted to identify optimal values for the parameters used in the proposed method. The optimal triangular mesh element size is between 5 cm and 6 cm; the angle threshold in the trace segment growth step is between 70° and 90°; the angle threshold in the trace segment connection step is between 50° and 70°, and the distance threshold should be at least 15 times the mean triangular mesh element size. The method is applied to the excavation face trace mapping of a drill-and-blast tunnel. The results show that the proposed discontinuity trace mapping method is fast and effective and could be used as a supplement to traditional direct measurement of discontinuity traces.

Desert Varnish - Preservation of Biofabrics/Implcations for Mars

NASA Technical Reports Server (NTRS)

Probst, Luke W.; Allen, Carlton C.; Thomas-Keprta, Kathie L.; Clemett, Simon J.; Longazo, Teresa G.; Nelman-Gonzalez, Mayra A.; Sams, Clarence

2002-01-01

Desert varnish is the orange to dark brown rind that accumulates on exposed rock surfaces in many arid environments. Samples from the Sonoran Desert of Arizona are composed predominantly of clays (illite, smectite) and Mn- and Fe- oxides (birnessite, hematite). Features that appear to be single organisms are found within the varnish and at the rock-varnish interface. Many of these features are embedded in films that strongly resemble the water-rich extracellular polysaccharides produced by diverse microorganisms. Most common are rod-shaped celllike objects, 0.5-2 microns in the longest dimension, located within the varnish coatings. Some of these objects are shown to contain amines by fluorescence microscopy. The rod-shaped objects are observed in various states of degradation, as indicated by C and S abundances. Rods with higher C and S abundances appear less degraded than those with lower concentrations of these two elements. Regions rich in apparent microbes are present, while other regions display Mn- and Fe-rich mineral fabrics with microbe-sized voids and no obvious cells. These textures are interpreted as biofabrics, preserved by the precipitation of Mn and Fe minerals. We are researching the preservation of biofabrics by desert varnish in Earth's geological record. Rock coatings may similarly preserve evidence of microbial life on the hyper-arid surface of Mars.

Detection of Hazardous Cavities Below a Road Using Combined Geophysical Methods

NASA Astrophysics Data System (ADS)

De Giorgi, L.; Leucci, G.

2014-07-01

Assessment of the risk arising from near-surface natural hazard is a crucial step in safeguarding the security of the roads in karst areas. It helps authorities and other related parties to apply suitable procedures for ground treatment, mitigate potential natural hazards and minimize human and economic losses. Karstic terrains in the Salento Peninsula (Apulia region—South Italy) is a major challenge to engineering constructions and roads due to extensive occurrence of cavities and/or sinkholes that cause ground subsidence and both roads and building collapse. Cavities are air/sediment-filled underground voids, commonly developed in calcarenite sedimentary rocks by the infiltration of rainwater into the ground, opening up, over a long period of time, holes and tunnels. Mitigation of natural hazards can best be achieved through careful geoscientific studies. Traditionally, engineers use destructive probing techniques for the detection of cavities across regular grids or random distances. Such probing is insufficient on its own to provide confidence that cavities will not be encountered. Frequency of probing and depth of investigation may become more expensive. Besides, probing is intrusive, non-continuous, slow, expensive and cannot provide a complete lateral picture of the subsurface geology. Near-surface cavities usually can be easily detected by surface geophysical methods. Traditional and recently developed measuring techniques in seismic, geoelectrics and georadar are suitable for economical investigation of hazardous, potentially collapsing cavities. The presented research focused on an integrated geophysical survey that was carried out in a near-coast road located at Porto Cesareo, a small village a few kilometers south west of Lecce (south Italy). The roads in this area are intensively affected by dangerous surface cracks that cause structural instability. The survey aimed to image the shallow subsurface structures, including karstic features, and evaluate their extent, as they may cause rock instability and lead to cracking of the road. Seismic refraction tomography and ground-penetrating radar surveys were carried out along several parallel traverses extending about 100 m on the cracked road. The acquired data were processed and interpreted integrally to elucidate the shallow structural setting of the site. Integrated interpretation led to the delineation of hazard zones rich with karstic features in the area. Most of these karstic features are associated with vertical and subvertical linear features and cavities. These features are the main reason of the rock instability that resulted in potentially dangerous cracking of road.

Hydrocarbons in phlogopite from Kasenyi kamafugitic rocks (SW Uganda): cross-correlated AFM, confocal microscopy and Raman imaging

PubMed Central

Moro, Daniele; Valdrè, Giovanni; Mesto, Ernesto; Scordari, Fernando; Lacalamita, Maria; Ventura, Giancarlo Della; Bellatreccia, Fabio; Scirè, Salvatore; Schingaro, Emanuela

2017-01-01

This study presents a cross-correlated surface and near surface investigation of two phlogopite polytypes from Kasenyi kamafugitic rocks (SW Uganda) by means of advanced Atomic Force Microscopy (AFM), confocal microscopy and Raman micro-spectroscopy. AFM revealed comparable nanomorphology and electrostatic surface potential for the two mica polytypes. A widespread presence of nano-protrusions located on the mica flake surface was also observed, with an aspect ratio (maximum height/maximum width) from 0.01 to 0.09. Confocal microscopy showed these features to range from few nm to several μm in dimension, and shapes from perfectly circular to ellipsoidic and strongly elongated. Raman spectra collected across the bubbles showed an intense and convolute absorption in the range 3000–2800 cm−1, associated with weaker bands at 1655, 1438 and 1297 cm−1, indicating the presence of fluid inclusions consisting of aliphatic hydrocarbons, alkanes and cycloalkanes, with minor amounts of oxygenated compounds, such as carboxylic acids. High-resolution Raman images provided evidence that these hydrocarbons are confined within the bubbles. This work represents the first direct evidence that phlogopite, a common rock-forming mineral, may be a possible reservoir for hydrocarbons. PMID:28098185

Characterization of Geologic Structures and Host Rock Properties Relevant to the Hydrogeology of the Standard Mine in Elk Basin, Gunnison County, Colorado

USGS Publications Warehouse

Caine, Jonathan S.; Manning, Andrew H.; Berger, Byron R.; Kremer, Yannick; Guzman, Mario A.; Eberl, Dennis D.; Schuller, Kathryn

2010-01-01

The Standard Mine Superfund Site is a source of mine drainage and associated heavy metal contamination of surface and groundwaters. The site contains Tertiary polymetallic quartz veins and fault zones that host precious and base metal sulfide mineralization common in Colorado. To assist the U.S. Environmental Protection Agency in its effort to remediate mine-related contamination, we characterized geologic structures, host rocks, and their potential hydraulic properties to better understand the sources of contaminants and the local hydrogeology. Real time kinematic and handheld global positioning systems were used to locate and map precisely the geometry of the surface traces of structures and mine-related features, such as portals. New reconnaissance geologic mapping, field and x-ray diffraction mineralogy, rock sample collection, thin-section analysis, and elemental geochemical analysis were completed to characterize hydrothermal alteration, mineralization, and subsequent leaching of metallic phases. Surface and subsurface observations, fault vein and fracture network characterization, borehole geophysical logging, and mercury injection capillary entry pressure data were used to document potential controls on the hydrologic system.

Geologic age: using radioactive decay to determine geologic age

USGS Publications Warehouse

,

1997-01-01

At the close of the 18th century, the haze of fantasy and mysticism that tended to obscure the true nature of the Earth was being swept away. Careful studies by scientists showed that rocks had diverse origins. Some rock layers, containing clearly identifiable fossil remains of fish and other forms of aquatic animal and plant life, originally formed in the ocean. Other layers, consisting of sand grains winnowed clean by the pounding surf, obviously formed as beach deposits that marked the shorelines of ancient seas. Certain layers are in the form of sand bars and gravel banks -- rock debris spread over the land by streams. Some rocks were once lava flows or beds of cinders and ash thrown out of ancient volcanoes; others are portions of large masses of once-molten rock that cooled very slowly far beneath the Earth's surface. Other rocks were so transformed by heat and pressure during the heaving and buckling of the Earth's crust in periods of mountain building that their original features were obliterated.

Geophysical interpretations west of and within the northwestern part of the Nevada Test Site

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

Grauch, V.J.; Sawyer, D.A.; Fridrich, C.J.

1997-12-31

This report focuses on interpretation of gravity and new magnetic data west of the Nevada Test Site (NTS) and within the northwestern part of NTS. The interpretations integrate the gravity and magnetic data with other geophysical, geological, and rock property data to put constraints on tectonic and magmatic features not exposed at the surface. West of NTS, where drill hole information is absent, these geophysical data provide the best available information on the subsurface. Interpreted subsurface features include calderas, intrusions, basalt flows and volcanoes, Tertiary basins, structurally high pre-Tertiary rocks, and fault zones. New features revealed by this study includemore » (1) a north-south buried tectonic fault east of Oasis Mountain, which the authors call the Hogback fault; (2) an east striking fault or accommodation zone along the south side of Oasis Valley basin, which they call the Hot Springs fault; (3) a NNE striking structural zone coinciding with the western margins of the caldera complexes; (4) regional magnetic highs that probably represent a thick sequence of Tertiary volcanic rocks; and (5) two probable buried calderas that may be related to the tuffs of Tolicha Peak and of Sleeping Butte, respectively.« less

U.S.A. National Surface Rock Density Map - Part 2

NASA Astrophysics Data System (ADS)

Winester, D.

2016-12-01

A map of surface rock densities over the USA has been developed by the NOAA-National Geodetic Survey (NGS) as part of its Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Program. GRAV-D is part of an international effort to generate a North American gravimetric geoid for use as the vertical datum reference surface. As a part of modeling process, it is necessary to eliminate from the observed gravity data the topographic and density effects of all masses above the geoid. However, the long-standing tradition in geoid modeling, which is to use an average rock density (e.g. 2.67 g/cm3), does not adequately represent the variety of lithologies in the USA. The U.S. Geological Survey has assembled a downloadable set of surface geologic formation maps (typically 1:100,000 to 1:500, 000 scale in NAD27) in GIS format. The lithologies were assigned densities typical of their rock type (Part 1) and these variety of densities were then rasterized and averaged over one arc-minute areas. All were then transformed into WGS84 datum. Thin layers of alluvium and some water bodies (interpreted to be less than 40 m thick) have been ignored in deference to underlying rocks. Deep alluvial basins have not been removed, since they represent significant fraction of local mass. The initial assumption for modeling densities will be that the surface rock densities extend down to the geoid. If this results in poor modeling, variable lithologies with depth can be attempted. Initial modeling will use elevations from the SRTM DEM. A map of CONUS densities is presented (denser lithologies are shown brighter). While a visual map at this scale does show detailed features, digital versions are available upon request. Also presented are some pitfalls of using source GIS maps digitized from variable reference sources, including the infamous `state line faults.'

Earth Observations taken by the Expedition 18 Crew

NASA Image and Video Library

2008-12-29

ISS018-E-015908 (29 Dec. 2008) --- The Biokovo Range in Croatia is featured in this image photographed by an Expedition 18 crewmember on the International Space Station. The Biokovo Range in Croatia is part of the Dinaric Alps extending northwest-southeast along the coastline of the Adriatic Sea. The Range itself is the location of a national park; the nearby city of Makarska, located between the mountains and the sea, is a popular tourist destination. The highest peak in the Biokovo Range, Sveti Jure (1762 meters above sea level), is reachable by road or hiking. The Range is comprised mainly of Mesozoic age carbonate rocks ? primarily limestone, a sedimentary rock type rich in calcium carbonate ? deposited in relatively warm, shallow waters. Later tectonic processes uplifted and exposed the carbonate rocks to erosion ? leading to a distinctive geological surface known as karst topography. Karst topography originates due to the chemical erosion of carbonate rocks by acids formed in surface and subsurface water; as the rock is dissolved, underground networks of drainages and caves form. As more underground void space develops through time, the overlaying rock and soil collapses to form a variety of landforms including sinkholes, blind valleys, and towers. In the Biokovo Range, much of the karst surface has a pitted appearance, made easily visible by early morning light in this astronaut photograph. The pitted appearance is produced by numerous circular or semi-circular collapse valleys known locally as vrtace. While this image captures Sveti Jure covered with snow, there are no glaciers or ice fields in the Biokovo Range.

A Case Study on the Strata Movement Mechanism and Surface Deformation Regulation in Chengchao Underground Iron Mine

NASA Astrophysics Data System (ADS)

Cheng, Guanwen; Chen, Congxin; Ma, Tianhui; Liu, Hongyuan; Tang, Chunan

2017-04-01

The regular pattern of surface deformation and the mechanism of underground strata movement, especially in iron mines constructed with the block caving method, have a great influence on infrastructure on the surface, so they are an important topic for research. Based on the engineering geology conditions and the surface deformation and fracture features in Chengchao Iron Mine, the mechanism of strata movement and the regular pattern of surface deformation in the footwall were studied by the geomechanical method, and the following conclusions can be drawn: I. The surface deformation process is divided into two stages over time, i.e., the chimney caving development stage and the post-chimney deformation stage. Currently, the surface deformation in Chengchao Iron Mine is at the post-chimney deformation stage. II. At the post-chimney deformation stage, the surface deformation and geological hazards in Chengchao Iron Mine are primarily controlled by the NWW-trending joints, with the phenomenon of toppling deformation and failure on the surface. Based on the surface deformation characteristics in Chengchao Iron Mine, the surface deformation area can be divided into the following four zones: the fracture extension zone, the fracture closure zone, the fracture formation zone and the deformation accumulation zone. The zones on the surface can be determined by the surface deformation characteristics. III. The cantilever beams near the chimney caving area, caused by the NWW-trending joints, have been subjected to toppling failure. This causes the different deformation and failure mechanisms in different locations of the deep rock mass. The deep rock can be divided into four zones, i.e., the fracture zone, fracture transition zone, deformation zone and undisturbed zone, according to the different deformation and failure mechanisms. The zones in the deep rock are the reason for the zones on the surface, so they can be determined by the zones on the surface. Through these findings, the degree of damage to the infrastructure in different locations can be determined based on the surface deformation zones. As the mining continues deeper, the development regulation of the zones on the surface and in deep rock mass can be further studied based on the zones in the deep rock.

VNIR spectral features observed by the Mars Exploration Rover Opportunity in hematite-bearing materials at Meridiani Planum

NASA Astrophysics Data System (ADS)

Farrand, W. H.; Bell, J. F.; Morris, R. V.; Joliff, B. L.; Squyres, S. W.; Souza, P. A.

2004-12-01

The Mars Exploration Rover Opportunity was sent to Meridiani Planum based largely on MGS TES spectroscopic evidence of a large surface exposure of coarse grained gray hematite. The presence of hematite at Meridiani Planum has been confirmed through thermal infrared spectroscopy by the rover's Mini-TES instrument and by in-situ measurements by its Moessbauer (MB) spectrometer. Several types of hematite, as expressed by differences in MB spectral parameters, have been associated with various rocks and soils examined in Eagle crater and on the surrounding plains. The host materials include the small spherules (informally known as "blueberries") littering the floor of Eagle crater and the plains of Meridiani, the outcrop rock itself, specific types of soils, and two measurements on unique rocks in the Shoemaker's Patio area of Eagle crater. At the visible to near infrared (VNIR) wavelengths covered by the rover's multispectral Panoramic camera (Pancam), gray hematite is spectrally neutral. However, multispectral observations by Pancam of some of these hematite-bearing materials show discernable spectral features. Specifically, portions of the outcrop visible in the walls of Eagle crater display a strong 535 nm absorption feature. This feature resembles a similar feature in laboratory spectra of red hematite, but the characteristic 860 nm absorption of red hematite is either absent or is instead replaced by a longer wavelength absorption centered on Pancam's 900 nm channel. The blueberries display a deep and broad absorption centered on 900 nm and as well as an increase in reflectance in the 1009 nm band. The shape of the absorption feature in the blueberries is consistent with that seen in red hematite, but again the band minimum is displaced to a longer wavelength than would be expected for red hematite. The blueberries also lack the prominent absorption at the shortest wavelengths that would be expected of red hematite. The unique hematite-bearing (or coated) rocks at Shoemaker's Patio lack the very strong 535 nm band depth of other portions of the outcrop but still have a stronger 535 nm feature than most of the outcrop. Interestingly, VNIR spectra more consistent with that expected for red hematite have been found in cuttings released by grinding into outcrop by the rover's Rock Abrasion Tool. The cause of the observed spectral features in the portions of outcrop with strong 535 nm band depths and of the reddish rocks in the Shoemaker's Patio area is believed to be attributable either to red hematite mixed with other Fe3+ - bearing phases (such as jarosite and/or schwertmannite) or, at the longer wavelengths, with Fe2+ - bearing phases (such as pyroxenes). Determination of the nature of these iron-bearing materials will further elucidate the geologic, aqueous and diagenetic history of the rocks at Meridiani Planum.

Mass Wasting in Planetary Environments: Implications for Seismicity

NASA Technical Reports Server (NTRS)

Weber, Renee; Nahm, Amanda; Schmerr, Nick

2015-01-01

On Earth, mass wasting events such as rock falls and landslides are well known consequences of seismic activity. Here we investigate the regional effects of seismicity in planetary environments with the goal of determining whether such surface features on the Moon, Mars, and Mercury could be triggered by fault motion.

Differentiating pedogenesis from diagenesis in early terrestrial paleoweathering surfaces formed on granitic composition parent materials

USGS Publications Warehouse

Driese, S.G.; Medaris, L.G.; Ren, M.; Runkel, Anthony C.; Langford, R.P.

2007-01-01

Unconformable surfaces separating Precambrian crystalline basement and overlying Proterozoic to Cambrian sedimentary rocks provide an exceptional opportunity to examine the role of primitive soil ecosystems in weathering and resultant formation of saprolite (weathered rock retaining rock structure) and regolith (weathered rock without rock structure), but many appear to have been affected by burial diagenesis and hydrothermal fluid flow, leading some researchers to discount their suitability for such studies. We examine one modern weathering profile (Cecil series), four Cambrian paleoweathering profiles from the North American craton (Squaw Creek, Franklin Mountains, Core SQ-8, and Core 4), one Neoproterozoic profile (Sheigra), and one late Paleoproterozoic profile (Baraboo), to test the hypothesis that these paleoweathering profiles do provide evidence of primitive terrestrial weathering despite their diagenetic and hydrothermal overprinting, especially additions of potassium. We employ an integrated approach using (1) detailed thin-section investigations to identify characteristic pedogenic features associated with saprolitization and formation of well-drained regoliths, (2) electron microprobe analysis to identify specific weathered and new mineral phases, and (3) geochemical mass balance techniques to characterize volume changes during weathering and elemental gains and losses of major and minor elements relative to the inferred parent materials. There is strong pedogenic evidence of paleoweathering, such as clay illuviation, sepic-plasmic fabrics, redoximorphic features, and dissolution and alteration of feldspars and mafic minerals to kaolinite, gibbsite, and Fe oxides, as well as geochemical evidence, such as whole-rock losses of Na, Ca, Mg, Si, Sr, Fe, and Mn greater than in modern profiles. Evidence of diagenesis includes net additions of K, Ba, and Rb determined through geochemical mass balance, K-feldspar overgrowths in overlying sandstone sections, and K-feldspars with reaction rims in weathered basement. The sub-Cambrian paleoweathering profiles formed on granite are remarkably similar to modern weathering profiles formed on granite, in spite of overprinting by potassium diagenesis. ?? 2007 by The University of Chicago. All rights reserved.

Clastic dikes of Heart Mountain fault breccia, northwestern Wyoming, and their significance

USGS Publications Warehouse

Pierce, W.G.

1979-01-01

Structural features in northwestern Wyoming indicate that the Heart Mountain fault movement was an extremely rapid, cataclysmic event that created a large volume of carbonate fault breccia derived entirely from the lower part of the upper plate. After fault movement had ceased, much of the carbonate fault breccia, here called calcibreccia, lay loose on the resulting surface of tectonic denudation. Before this unconsolidated calcibreccia could be removed by erosion, it was buried beneath a cover of Tertiary volcanic rocks: the Wapiti Formation, composed of volcanic breccia, poorly sorted volcanic breccia mudflows, and lava flows, and clearly shown in many places by inter lensing and intermixing of the calcibreccia with basal volcanic rocks. As the weight of volcanic overburden increased, the unstable water-saturated calcibreccia became mobile and semifluid and was injected upward as dikes into the overlying volcanic rocks and to a lesser extent into rocks of the upper plate. In some places the lowermost part of the volcanic overburden appears to have flowed with the calcibreccia to form dike like bodies of mixed volcanic rock and calcibreccia. One calcibreccia dike even contains carbonized wood, presumably incorporated into unconsolidated calcibreccia on the surface of tectonic denudation and covered by volcanic rocks before moving upward with the dike. Angular xenoliths of Precambrian rocks, enclosed in another calcibreccia dike and in an adjoining dikelike mass of volcanic rock as well, are believed to have been torn from the walls of a vent and incorporated into the basal part of the Wapiti Formation overlying the clastic carbonate rock on the fault surface. Subsequently, some of these xenoliths were incorporated into the calcibreccia during the process of dike intrusion. Throughout the Heart Mountain fault area, the basal part of the upper-plate blocks or masses are brecciated, irrespective of the size of the blocks, more intensely at the base and in places extending upward for several tens of meters. North of Republic Mountain a small 25-m-high upper-plate mass, brecciated to some degree throughout, apparently moved some distance along the Heart Mountain fault as brecciated rock. Calcibreccia dikes intrude upward from the underlying 2 m of fault breccia into the lower part of the mass and also from its top into the overlying volcanic rocks; an earthquake-related mechanism most likely accounts for the observed features of this deformed body. Calcibreccia dikes are more common within the bedding-plane phase of the Heart Mountain fault but also occur in its transgressive and former land-surface phases. Evidence that the Wapiti Formation almost immediately buried loose, unconsolidated fault breccia that was the source of the dike rock strongly suggests a rapid volcanic deposition over the area in which clastic dikes occur, which is at least 75 km long. Clastic dikes were injected into both the upper-plate and the volcanic rocks at about the same time, after movement on the Heart Mouuntain fault had ceased, and therefore do not indicate a fluid-flotation mechanism for the Heart Mountain fault. The difference between contacts of the clastic dikes with both indurated and unconsolidated country rock is useful in field mapping at localities where it is difficult to distinguish between volcanic rocks of the Cathedral Cliffs and Lamar River Formations, and the Wapiti Formation. Thus, calcibreccia dikes in the Cathedral Cliffs and Lamar River Formations show a sharp contact because the country rock solidified prior to fault movement, whereas calcibreccia dikes in the Wapiti Formation in many instances show a transitional or semifluid contact because the country rock was still unconsolidated or semifluid at the time of dike injection.

Mars Pathfinder [foldout].

PubMed

1997-12-05

The following foldout present images and analysis from the Mars Pathfinder Mission that are discussed in seven subsequent Reports. The center is a four-page panorama of the surface of Mars around the lander (Plate 1). The back of the foldout contains surface images (Plate 7), a different perspective of the landing site (Plate 2), rover targets (Plate 3), locations of rocks and other features (Plate 6) and data analysis (Plates 4, 4, 8, 9, and 10).

Validation of a New Elastoplastic Constitutive Model Dedicated to the Cyclic Behaviour of Brittle Rock Materials

NASA Astrophysics Data System (ADS)

Cerfontaine, B.; Charlier, R.; Collin, F.; Taiebat, M.

2017-10-01

Old mines or caverns may be used as reservoirs for fuel/gas storage or in the context of large-scale energy storage. In the first case, oil or gas is stored on annual basis. In the second case pressure due to water or compressed air varies on a daily basis or even faster. In both cases a cyclic loading on the cavern's/mine's walls must be considered for the design. The complexity of rockwork geometries or coupling with water flow requires finite element modelling and then a suitable constitutive law for the rock behaviour modelling. This paper presents and validates the formulation of a new constitutive law able to represent the inherently cyclic behaviour of rocks at low confinement. The main features of the behaviour evidenced by experiments in the literature depict a progressive degradation and strain of the material with the number of cycles. A constitutive law based on a boundary surface concept is developed. It represents the brittle failure of the material as well as its progressive degradation. Kinematic hardening of the yield surface allows the modelling of cycles. Isotropic softening on the cohesion variable leads to the progressive degradation of the rock strength. A limit surface is introduced and has a lower opening than the bounding surface. This surface describes the peak strength of the material and allows the modelling of a brittle behaviour. In addition a fatigue limit is introduced such that no cohesion degradation occurs if the stress state lies inside this surface. The model is validated against three different rock materials and types of experiments. Parameters of the constitutive laws are calibrated against uniaxial tests on Lorano marble, triaxial test on a sandstone and damage-controlled test on Lac du Bonnet granite. The model is shown to reproduce correctly experimental results, especially the evolution of strain with number of cycles.

Earth Observations taken by the Expedition 22 Crew

NASA Image and Video Library

2010-01-31

ISS022-E-058538 (31 Jan. 2010) --- Sir Bani Yas Island is featured in this image photographed by an Expedition 22 crew member on the International Space Station. Sir Bani Yas Island is located in the Persian Gulf near the western coastline of the United Arab Emirates (UAE). The approximately 14-kilometers x nine-kilometers island is the surface expression of a salt dome, and is one of several such islands in the Persian Gulf. During past periods of alternating wet and dry climate, sometimes involving areas with high rates of evaporation in enclosed basins, thick layers of salt minerals (such as halite ? common table salt, or gypsum ? a major component of wallboard) were deposited. These layers were subsequently buried by sediments; with enough overlaying material and depth of burial, the salt layers can begin to flow. Salt has lower density than the surrounding rock and it tends to flow upwards, pushing up the overlaying layers of rock to form a salt dome. While many salt domes retain a cap of the youngest rock layers at the surface, in some cases the underlaying salt extrudes onto the surface. This photograph illustrates the varying character of surfaces on the island. The central mountains of Jebel Wahid (center) mark the location of the Sir Bani Yas salt dome. The dome has breached the surface but exposed salt - primarily gypsum - is removed by erosion, leaving a rugged, insoluble cap formed from fragments of the overlaying sedimentary and volcanic rocks. Sand and silt derived from the Jebel Wahid area and surrounding gravel cover forms beaches along the outer edge of the island.

Seismically damaged regolith as self-organized fragile geological feature

NASA Astrophysics Data System (ADS)

Sleep, Norman H.

2011-12-01

The S-wave velocity in the shallow subsurface within seismically active regions self-organizes so that typical strong dynamic shear stresses marginally exceed the Coulomb elastic limit. The dynamic velocity from major strike-slip faults yields simple dimensional relations. The near-field velocity pulse is essentially a Love wave. The dynamic shear strain is the ratio of the measured particle velocity over the deep S-wave velocity. The shallow dynamic shear stress is this quantity times the local shear modulus. The dynamic shear traction on fault parallel vertical planes is finite at the free surface. Coulomb failure occurs on favorably oriented fractures and internally in intact rock. I obtain the equilibrium shear modulus by starting a sequence of earthquakes with intact stiff rock extending all the way to the surface. The imposed dynamic shear strain in stiff rock causes Coulomb failure at shallow depths and leaves cracks in it wake. Cracked rock is more compliant than the original intact rock. Cracked rock is also weaker in friction, but shear modulus changes have a larger effect. Each subsequent event causes additional shallow cracking until the rock becomes compliant enough that it just reaches Coulomb failure over a shallow depth range of tens to hundreds of meters. Further events maintain the material at the shear modulus as a function where it just fails. The formalism provided in the paper yields reasonable representation of the S-wave velocity in exhumed sediments near Cajon Pass and the San Fernando Valley of California. A general conclusion is that shallow rocks in seismically active areas just become nonlinear during typical shaking. This process causes transient changes in S-wave velocity, but not strong nonlinear attenuation of seismic waves. Wave amplitudes significantly larger than typical ones would strongly attenuate and strongly damage the rock.

Wildlife associated with scoria outcrops: implications for reclamation of surface-mined lands

Treesearch

Mark A. Rumble

1989-01-01

Bird and mammal populations using scoria rock outcrop and adjacentsagebrush/grassland habitats were studied. Bird populations and bird species richness were greater in the outcrop habitats than in the surrounding sagebrush/grassland habitats. These differences were attributedto the structural features provided by the outcrops. Most, but not all, small mammal...

Mineral Features of EETA79001 Martian Meteorite Revealed by Point-Counting Raman Measurements as Anticipated for In-Situ Exploration on Planetary Surfaces

NASA Technical Reports Server (NTRS)

Wang, Alian; Kuebler, Karla E.; Jolliff, Brad L.

2000-01-01

The distribution of pyroxenes of different Mg' and olivines of different Fo in lithologies A and B were obtained. Three types of olivine formed at different stages of rock formation were found by point counting Raman measurements along linear traverses.

Mars and earth - Comparison of cold-climate features

NASA Technical Reports Server (NTRS)

Lucchitta, B. K.

1981-01-01

On earth, glacial and periglacial features are common in areas of cold climate. On Mars, the temperature of the present-day surface is appropriate for permafrost, and the presence of water is suspected from data relating to the outgassing of the planet, from remote-sensing measurements over the polar caps and elsewhere on the Martian surface, and from recognition of fluvial morphological features such as channels. These observations and the possibility that ice could be in equilibrium with the high latitudes north and south of + or - 40 deg latitude suggest that glacial and periglacial features should exist on the planet. Morphological studies based mainly on Viking pictures indicate many features that can be attributed to the action of ice. Among these features are extensive talus aprons; debris avalanches; flows that resemble glaciers or rock glaciers; ridges that look like moraines; various types of patterned ground, scalloped scarps, and chaotically collapsed terrain that could be attributed to thermokarst processes; and landforms that may reflect the interaction of volcanism and ice.

The anatomy of an anomaly. [data on LANDSAT multispectral band scanning in Wyoming

NASA Technical Reports Server (NTRS)

Short, N. M.; Marrs, R. W.

1975-01-01

An anomalous tonal pattern, apparently associated with the Beaver Creek oil field in central Wyoming, was identified using an MSS Band 5 to 4 ratio image made from digital LANDSAT data. This pattern was attributed to an increase in iron with rocks and/or soils which might have resulted from escaping hydrocarbons. The nature of this anomaly was investigated by producing several different combinations of band ratios and by conducting appropriate field studies. The results indicated (1) the existence of a well-defined oval feature related to exposure of iron-cemented red sandstones in a badlands topography, (2) a broader iron-influenced anomaly surrounding this feature, and (3) a spectral response of the rocks, soils, and alluvium making up this iron-colored surface that is readily distinguishable from that of iron-rich reddish Chugwater siltstones exposed in nearby anticlines. The general pattern of the broad anomaly extending beyond the Beaver Creek field is controlled by several factors including variations in vegetation (mainly sage and tall grasses), soil composition and moisture, and topography in addition to variations in iron content of the rock materials. From the available evidence, there is no provable correlation between the oval or the broad anomalies and the distribution of petroleum-producing structures or possible surface alteration effects related to uranium deposits known to occur within this region.

In Situ Observation of Rock Spalling in the Deep Tunnels of the China Jinping Underground Laboratory (2400 m Depth)

NASA Astrophysics Data System (ADS)

Feng, Xia-Ting; Xu, Hong; Qiu, Shi-Li; Li, Shao-Jun; Yang, Cheng-Xiang; Guo, Hao-Sen; Cheng, Yuan; Gao, Yao-Hui

2018-04-01

To study rock spalling in deep tunnels at China Jinping Underground Laboratory Phase II (CJPL-II), photogrammetry method and digital borehole camera were used to quantify key features of rock spalling including orientation, thickness of slabs and the depth of spalling. The failure mechanism was analysed through scanning electron microscope and numerical simulation based on FLAC3D. Observation results clearly showed the process of rock spalling failure: a typical spalling pattern around D-shaped tunnels after top-heading and bottom bench were discovered. The orientation and thickness of the slabs were obtained. The slabs were parallel to the excavated surfaces of the tunnel and were related to the shape of the tunnel surface and orientation of the principal stress. The slabs were alternately thick and thin, and they gradually increased in thickness from the sidewall inwards. The form and mechanism of spalling at different locations in the tunnels, as influenced by stress state and excavation, were analysed. The result of this study was helpful to those rethinking the engineering design, including the excavation and support of tunnels, or caverns, at high risk of spalling.

Thermal Infrared Spectral Band Detection Limits for Unidentified Surface Materials

NASA Technical Reports Server (NTRS)

Kirkland, Laurel E.; Herr, Kenneth C.; Salisbury, John W.

2001-01-01

Infrared emission spectra recorded by airborne or satellite spectrometers can be searched for spectral features to determine the composition of rocks on planetary surfaces. Surface materials are identified by detections of characteristic spectral bands. We show how to define whether to accept an observed spectral feature as a detection when the target material is unknown. We also use remotely sensed spectra measured by the Thermal Emission Spectrometer (TES) and the Spatially Enhanced Broadband Array Spectrograph System to illustrate the importance of instrument parameters and surface properties on band detection limits and how the variation in signal-to-noise ratio with wavelength affects the bands that are most detectable for a given instrument. The spectrometer's sampling interval, spectral resolution, signal-to-noise ratio as a function of wavelength, and the sample's surface properties influence whether the instrument can detect a spectral feature exhibited by a material. As an example, in the 6-13 micrometer wavelength region, massive carbonates exhibit two bands: a very strong, broad feature at approximately 6.5 micrometers and a less intense, sharper band at approximately 11.25 micrometers. Although the 6.5-micrometer band is stronger and broader in laboratory-measured spectra, the 11.25-micrometer band will cause a more detectable feature in TES spectra.

Basic processes and factors determining the evolution of collapse sinkholes: a sensitivity study

NASA Astrophysics Data System (ADS)

Romanov, Douchko; Kaufmann, Georg

2017-04-01

Collapse sinkholes appear as closed depressions at the surface. The origin of these karst features is related to the continuous dissolution of the soluble rock caused by a focussed sub-surface flow. Water flowing along a preferential pathway through fissures and fractures within the phreatic part of a karst aquifer is able to dissolve the rock (limestone, gypsum, anhydrite). With time, the dissolved void volume increases and part of the ceiling above the stream can become unstable, collapses, and accumulates as debris in the flow path. The debris partially blocks the flow and thus activates new pathways. Because of the low compaction of the debris (high hydraulic conductivity), the flow and the dissolution rates within this crushed zone remain high. This allows a relatively fast dissolutional and erosional removal of the crushed material and the development of new empty voids. The void volume expands upwards towards the surface until a collapse sinkhole is formed. The collapse sinkholes exhibit a large variety of shapes (cylindrical, cone-, bowl-shaped), depths (from few to few hundred meters) and diameters (meters up to hundreds of meters). Two major processes are responsible for this diversity: a) the karst evolution of the aquifer - responsible for the dissolutional and erosional removal of material; b) the mechanical evolution of the host rock and the existence of structural features, faults for example, which determine the stability and the magnitude of the subsequent collapses. In this work we demonstrate the influence of the host rock type, the hydrological and geological boundary conditions, the chemical composition of the flowing water, and the geometry and the scale of the crushed zone, on the location and the evolution of the growing sinkhole. We demonstrate the ability of the karst evolution models to explain, at least qualitatively, the growth and the morphology of the collapse sinkholes and to roughly predict their shape and location. Implementing simple rules that describe the mechanical collapse, we come to the conclusion that a complete quantitative and qualitative description of a collapse sinkhole is possible, but for this it is necessary to take into account also the mechanical properties of the rock and the processes determining the mechanics of the collapses.

Spectroscopy of Moses Rock Kimberlite Diatreme

NASA Technical Reports Server (NTRS)

Pieters, C. M.; Mustard, J. F.

1985-01-01

Three types of remote sensing data (Airborne Imaging Spectroscopy (AIS), NS001, Zeiss IR-photographs) were obtained for the Moses Rock kimberlite dike in southern Utah. The goal is to identify and characterize the mantle derived mafic component in such volcanic features. The Zeiss and NS001 images provide information on the regional setting and allow units of the dike to be distinguished from surrounding material. A potential unmapped satellite dike was identified. The AIS data provide characterizing information of the surface composition of the dike. Serpentized olivine-bearing soils are (tentatively) identified from the AIS spectra for a few areas within the dike.

Discovery Served Up in a Bowl

NASA Technical Reports Server (NTRS)

2004-01-01

This image from the Mars Exploration Rover Opportunity's panoramic camera is an approximate true-color rendering of the exceptional rock called 'Berry Bowl' in the 'Eagle Crater' outcrop. The study of this 'blueberry-strewn' area and the identification of hematite as the major iron-bearing element within these sphere-like grains helped scientists confirm their hypothesis that the hematite in these martian spherules was deposited in water. To separately analyze the mineralogical content of three main features within this area -- blueberries, dust and rock -- it was important that the rock abrasion tool's brush was able to rest on a relatively berry-free spot. The rock's small size and crowd of berries made the 10-minute brushing a challenge to plan and execute. The successful brushing on the target whimsically referred to as 'Near Empty' on the rover's 48th sol on Mars left a dust-free impression for subsequent examination by the rover's spectrometers. No grinding was necessary on the rock because spectral data obtained on the dust-free surface were sufficient to verify that the rock's chemical composition differs significantly from the hematite-rich berries.

Surface features on Mars: Ground-based albedo and radar compared with Mariner 9 topography

NASA Technical Reports Server (NTRS)

Frey, H.

1973-01-01

Earth-based albedo maps of Mars were compared with Mariner 9 television data and ground-based radar profiles to investigate the nature of the bright and dark albedo features. Little correlation was found except at the boundaries of classical albedo features, where some topographic control is indicated. Wind-blown dust models for seasonal and secular albedo variations are supported, but it is not clear whether the fines are derived from bright or dark parent rock. Mars, like the Earth and Moon, has probably generated two distinct types of crustal material.

Highest Resolution Topography of 433 Eros and Implications for MUSES-C

NASA Technical Reports Server (NTRS)

Cheng, A. F.; Barnouin-Jha, O.

2003-01-01

The highest resolution observations of surface morphology and topography at asteroid 433 Eros were obtained by the Near Earth Asteroid Rendezvous (NEAR) Shoemaker spacecraft on 12 February 2001, as it landed within a ponded deposit on Eros. Coordinated observations were obtained by the imager and the laser rangefinder, at best image resolution of 1 cm/pixel and best topographic resolution of 0.4 m. The NEAR landing datasets provide unique information on rock size and height distributions and regolith processes. Rocks and soil can be distinguished photometrically, suggesting that bare rock is indeed exposed. The NEAR landing data are the only data at sufficient resolution to be relevant to hazard assessment on future landed missions to asteroids, such as the MUSES-C mission which will land on asteroid 25143 (1998 SF36) in order to obtain samples. In a typical region just outside the pond where NEAR landed, the areal coverage by resolved positive topographic features is 18%. At least one topographic feature in the vicinity of the NEAR landing site would have been hazardous for a spacecraft.

Microstructural investigations on carbonate fault core rocks in active extensional fault zones from the central Apennines (Italy)

NASA Astrophysics Data System (ADS)

Cortinovis, Silvia; Balsamo, Fabrizio; Storti, Fabrizio

2017-04-01

The study of the microstructural and petrophysical evolution of cataclasites and gouges has a fundamental impact on both hydraulic and frictional properties of fault zones. In the last decades, growing attention has been payed to the characterization of carbonate fault core rocks due to the nucleation and propagation of coseismic ruptures in carbonate successions (e.g., Umbria-Marche 1997, L'Aquila 2009, Amatrice 2016 earthquakes in Central Apennines, Italy). Among several physical parameters, grain size and shape in fault core rocks are expected to control the way of sliding along the slip surfaces in active fault zones, thus influencing the propagation of coseismic ruptures during earthquakes. Nevertheless, the role of grain size and shape distribution evolution in controlling the weakening or strengthening behavior in seismogenic fault zones is still not fully understood also because a comprehensive database from natural fault cores is still missing. In this contribution, we present a preliminary study of seismogenic extensional fault zones in Central Apennines by combining detailed filed mapping with grain size and microstructural analysis of fault core rocks. Field mapping was aimed to describe the structural architecture of fault systems and the along-strike fault rock distribution and fracturing variations. In the laboratory we used a Malvern Mastersizer 3000 granulometer to obtain a precise grain size characterization of loose fault rocks combined with sieving for coarser size classes. In addition, we employed image analysis on thin sections to quantify the grain shape and size in cemented fault core rocks. The studied fault zones consist of an up to 5-10 m-thick fault core where most of slip is accommodated, surrounded by a tens-of-meters wide fractured damage zone. Fault core rocks consist of (1) loose to partially cemented breccias characterized by different grain size (from several cm up to mm) and variable grain shape (from very angular to sub-rounded), and (2) very fine-grained gouges (< 1 mm) localized along major and minor mirror-like slip surfaces. Damage zones mostly consist of fractured rocks and, locally, pulverized rocks. Collectively, field observations and laboratory analyses indicate that within the fault cores of the studied fault zones, grain size progressively decreases approaching the master slip surfaces. Furthermore, grain shape changes from very angular to sub-rounded clasts moving toward the master slip surfaces. These features suggest that the progressive evolution of grain size and shape distributions within fault cores may have determined the development of strain localization by the softening and cushioning effects of smaller particles in loose fault rocks.

Weathering Profiles in Phosphorus-Rich Rocks at Gusev Crater, Mars, Suggest Dissolution of Phosphate Minerals into Potentially Habitable Near-Neutral Waters.

PubMed

Adcock, Christopher T; Hausrath, Elisabeth M

2015-12-01

Abundant evidence indicates that significant surface and near-surface liquid water has existed on Mars in the past. Evaluating the potential for habitable environments on Mars requires an understanding of the chemical and physical conditions that prevailed in such aqueous environments. Among the geological features that may hold evidence of past environmental conditions on Mars are weathering profiles, such as those in the phosphorus-rich Wishstone-class rocks in Gusev Crater. The weathering profiles in these rocks indicate that a Ca-phosphate mineral has been lost during past aqueous interactions. The high phosphorus content of these rocks and potential release of phosphorus during aqueous interactions also make them of astrobiological interest, as phosphorus is among the elements required for all known life. In this work, we used Mars mission data, laboratory-derived kinetic and thermodynamic data, and data from terrestrial analogues, including phosphorus-rich basalts from Idaho, to model a conceptualized Wishstone-class rock using the reactive transport code CrunchFlow. Modeling results most consistent with the weathering profiles in Wishstone-class rocks suggest a combination of chemical and physical erosion and past aqueous interactions with near-neutral waters. The modeling results also indicate that multiple Ca-phosphate minerals are likely in Wishstone-class rocks, consistent with observations of martian meteorites. These findings suggest that Gusev Crater experienced a near-neutral phosphate-bearing aqueous environment that may have been conducive to life on Mars in the past. Mars-Gusev Crater-Wishstone-Reactive transport modeling-CrunchFlow-Aqueous interactions-Neutral pH-Habitability.

Some surface characteristics and gas interactions of Apollo 14 fines and rock fragments.

NASA Technical Reports Server (NTRS)

Cadenhead, D. A.; Wagner, N. J.; Jones, B. R.; Stetter, J. R.

1972-01-01

Comprehensive survey of the physical surface characteristics of Apollo 14 fines, two fragments of a breccia (14321), and a crystalline rock (14310). The survey was carried out with optical and both scanning and transmission electron microscopy and by studying the adsorption of a variety of gases including nitrogen, hydrogen, and water vapor. Our objective in the optical microscope study was to relate the visible geological and petrological features to the surface properties. Electron microscopy particularly helped relate surface roughness and particle fusion to gas adsorption and pore structure. The fine sample (14163,111) had a surface area of 0.210 sq m/g and a helium density of 2.9 g/cc. Similar values have been observed with breccia fragments. Other observations include physical adsorption of molecular hydrogen at low temperatures and of water vapor at ambient temperatures. It is concluded that these particular lunar materials, while capable of adsorbing water vapor, do not retain it for any significant time at low pressures, nor, under lunar conditions, is there any indication of absorption or penetration.

Assessment of Mars Pathfinder landing site predictions

USGS Publications Warehouse

Golombek, M.P.; Moore, H.J.; Haldemann, A.F.C.; Parker, T.J.; Schofield, J.T.

1999-01-01

Remote sensing data at scales of kilometers and an Earth analog were used to accurately predict the characteristics of the Mars Pathfinder landing site at a scale of meters. The surface surrounding the Mars Pathfinder lander in Ares Vallis appears consistent with orbital interpretations, namely, that it would be a rocky plain composed of materials deposited by catastrophic floods. The surface and observed maximum clast size appears similar to predictions based on an analogous surface of the Ephrata Fan in the Channeled Scabland of Washington state. The elevation of the site measured by relatively small footprint delay-Doppler radar is within 100 m of that determined by two-way ranging and Doppler tracking of the spacecraft. The nearly equal elevations of the Mars Pathfinder and Viking Lander 1 sites allowed a prediction of the atmospheric conditions with altitude (pressure, temperature, and winds) that were well within the entry, descent, and landing design margins. High-resolution (~38 m/pixel) Viking Orbiter 1 images showed a sparsely cratered surface with small knobs with relatively low slopes, consistent with observations of these features from the lander. Measured rock abundance is within 10% of that expected from Viking orbiter thermal observations and models. The fractional area covered by large, potentially hazardous rocks observed is similar to that estimated from model rock distributions based on data from the Viking landing sites, Earth analog sites, and total rock abundance. The bulk and fine-component thermal inertias measured from orbit are similar to those calculated from the observed rock size-frequency distribution. A simple radar echo model based on the reflectivity of the soil (estimated from its bulk density), and the measured fraction of area covered by rocks was used to approximate the quasi-specular and diffuse components of the Earth-based radar echos. Color and albedo orbiter data were used to predict the relatively dust free or unweathered surface around the Pathfinder lander compared to the Viking landing sites. Comparisons with the experiences of selecting the Viking landing sites demonstrate the enormous benefit the Viking data and its analyses and models had on the successful predictions of the Pathfinder site. The Pathfinder experience demonstrates that, in certain locations, geologic processes observed in orbiter data can be used to infer surface characteristics where those processes dominate over other processes affecting the Martian surface layer. Copyright 1999 by the American Geophysical Union.

Veneers, rinds, and fracture fills: Relatively late alteration of sedimentary rocks at Meridiani Planum, Mars

USGS Publications Warehouse

Knoll, A.H.; Jolliff, B.L.; Farrand, W. H.; Bell, J.F.; Clark, B. C.; Gellert, Ralf; Golombek, M.P.; Grotzinger, J.P.; Herkenhoff, K. E.; Johson, J.R.; McLennam, S.M.; Morris, Robert; Squyres, S. W.; Sullivan, R.; Tosca, N.J.; Yen, A.; Learner, Z.

2008-01-01

Veneers and thicker rinds that coat outcrop surfaces and partially cemented fracture fills formed perpendicular to bedding document relatively late stage alteration of ancient sedimentary rocks at Meridiani Planum, Mars. The chemistry of submillimeter thick, buff-colored veneers reflects multiple processes at work since the establishment of the current plains surface. Veneer composition is dominated by the mixing of silicate-rich dust and sulfate-rich outcrop surface, but it has also been influenced by mineral precipitation, including NaCl, and possibly by limited physical or chemical weathering of sulfate minerals. Competing processes of chemical alteration (perhaps mediated by thin films of water or water vapor beneath blanketing soils) and sandblasting of exposed outcrop surfaces determine the current distribution of veneers. Dark-toned rinds several millimeters thick reflect more extensive surface alteration but also indicate combined dust admixture, halite precipitation, and possible minor sulfate removal. Cemented fracture fills that are differentially resistant to erosion occur along the margins of linear fracture systems possibly related to impact. These appear to reflect limited groundwater activity along the margins of fractures, cementing mechanically introduced fill derived principally from outcrop rocks. The limited thickness and spatial distribution of these three features suggest that aqueous activity has been rare and transient or has operated at exceedingly low rates during the protracted interval since outcropping Meridiani strata were exposed on the plains surface. Copyright 2008 by the American Geophysical Union.

A 'Pot of Gold' Rich with Nuggets

NASA Technical Reports Server (NTRS)

2004-01-01

This close-up image taken by the Mars Exploration Rover Spirit highlights the nodular nuggets that cover the rock dubbed 'Pot of Gold.' These nuggets appear to stand on the end of stalk-like features. The surface of the rock is dotted with fine-scale pits. Data from the rover's scientific instruments have shown that Pot of Gold contains the mineral hematite, which can be formed with or without water.

Scientists are planning further observations of this rock, which they hope will yield more insight into the hematite's origins as well as how the enigmatic nuggets formed.

This image was taken by Spirit's microscopic imager on sol 162 (June 17, 2004). The observed area is 3 centimeters by 3 centimeters (1.2 inches by 1.2 inches)

A 'Pot of Gold' Rich with Nuggets (Sol 163-2)

NASA Technical Reports Server (NTRS)

2004-01-01

This close-up image taken by the Mars Exploration Rover Spirit highlights the nobular nuggets that cover the rock dubbed 'Pot of Gold.' These nuggets appear to stand on the end of stalk-like features. The surface of the rock is dotted with fine-scale pits. Data from the rover's scientific instruments have shown that Pot of Gold contains the mineral hematite, which can be formed with or without water.

Scientists are planning further observations of this rock, which they hope will yield more insight into the hematite's origins as well as how the enigmatic nuggets formed.

This image was taken by Spirit's microscopic imager on sol 163 (June 18, 2004). The observed area is 3 centimeters by 3 centimeters (1.2 inches by 1.2 inches).

A 'Pot of Gold' Rich with Nuggets (Sol 163)

NASA Technical Reports Server (NTRS)

2004-01-01

This close-up image taken by the Mars Exploration Rover Spirit highlights the nodular nuggets that cover the rock dubbed 'Pot of Gold.' These nuggets appear to stand on the end of stalk-like features. The surface of the rock is dotted with fine-scale pits. Data from the rover's scientific instruments have shown that Pot of Gold contains the mineral hematite, which can be formed with or without water.

Scientists are planning further observations of this rock, which they hope will yield more insight into the hematite's origins as well as how the enigmatic nuggets formed.

This image was taken by Spirit's microscopic imager on sol 163 (June 18, 2004). The observed area is 3 centimeters by 3 centimeters (1.2 inches by 1.2 inches).

Gravity, magnetic, and physical property data in the Smoke Creek Desert area, northwest Nevada

USGS Publications Warehouse

Tilden, Janet E.; Ponce, David A.; Glen, Jonathan M.G.; Chuchel, Bruce A.; Tushman, Kira; Duvall, Alison

2006-01-01

The Smoke Creek Desert, located approximately 100 km (60 mi) north of Reno near the California-Nevada border, is a large basin situated along the northernmost parts of the Walker Lane Belt (Stewart, 1988), a physiographic province defined by northwest-striking topographic features and strike-slip faulting. Because geologic framework studies play an important role in understanding the hydrology of the Smoke Creek Desert, a geologic and geophysical effort was begun to help determine basin geometry, infer structural features, and estimate depth to Pre-Cenozoic rocks, or basement. In May and June of 2004, and June of 2005, the U.S. Geological Survey (USGS) collected 587 new gravity stations, more than 160 line-kilometers (100 line-miles) of truck-towed magnetometer data, and 111 rock property samples in the Smoke Creek Desert and vicinity in northwest Nevada, as part of an effort to characterize its hydrogeologic framework. In the Smoke Creek Desert area, gravity highs occur over rocks of the Skedaddle Mountains, Fox Range, Granite Range, and over portions of Tertiary volcanic rocks in the Buffalo Hills. These gravity highs likely reflect basement rocks, either exposed at the surface or buried at shallow depths. The southern Smoke Creek Desert corresponds to a 25-mGal isostatic gravity low, which corresponds with a basin depth of approximately 2 km. Magnetic highs are likely due to granitic, andesitic, and metavolcanic rocks, whereas magnetic lows are probably associated with less magnetic gneiss and metasedimentary rocks in the region. Three distinctive patterns of magnetic anomalies occur throughout the Smoke Creek Desert and Squaw Creek Valley, likely reflecting three different geological and structural settings.

X-ray characterization techniques for the assessment of surface damage in crystalline wafers: A model study in AlN

NASA Astrophysics Data System (ADS)

Bobea, M.; Tweedie, J.; Bryan, I.; Bryan, Z.; Rice, A.; Dalmau, R.; Xie, J.; Collazo, R.; Sitar, Z.

2013-03-01

A high-resolution X-ray diffraction method with enhanced surface sensitivity has been used to investigate the effects of various polishing steps on the near-surface region of single crystal substrates. The method involves the study of a highly asymmetric reflection, observable under grazing incidence conditions. Analysis of rocking curve measurements and reciprocal space maps (RSMs) revealed subtle structural differences between the polished substrates. For aluminum nitride wafers, damage induced from diamond sawing and mechanical polishing was readily identifiable by on-axis rocking curves, but this method was unable to distinguish between sample surfaces subjected to various degrees of chemical mechanical polishing (CMP). To characterize sufficiently these surfaces, (10.3) RSMs were measured to provide both qualitative and quantitative information about the near-surface region. Two features present in the RSMs were utilized to quantitatively assess the polished wafers: the magnitude of the diffuse scatter in the omega-scans and the elongation of the crystal truncation rod. The method is able to distinguish between different degrees of CMP surface preparation and provides metrics to quantify subsurface damage after this polishing step.

Space Weathering of Lunar Rocks and Regolith Grains

NASA Technical Reports Server (NTRS)

Keller, L. P.

2013-01-01

The exposed surfaces of lunar soil grains and lunar rocks become modified and coated over time with a thin rind of material (patina) through complex interactions with the space environment. These interactions encompass many processes including micrometeorite impacts, vapor and melt deposition, and solar wind implantation/sputtering effects that collectively are referred to as "space weathering". Studies of space weathering effects in lunar soils and rocks provide important clues to understanding the origin and evolution of the lunar regolith as well as aiding in the interpretation of global chemical and mineralogical datasets obtained by remote-sensing missions. The interpretation of reflectance spectra obtained by these missions is complicated because the patina coatings obscure the underlying rock mineralogy and compositions. Much of our understanding of these processes and products comes from decades of work on remote-sensing observations of the Moon, the analysis of lunar samples, and laboratory experiments. Space weathering effects collectively result in a reddened continuum slope, lowered albedo, and attenuated absorption features in reflectance spectra of lunar soils as compared to finely comminuted rocks from the same Apollo sites. Space weathering effects are largely surface-correlated, concentrated in the fine size fractions, and occur as amorphous rims on individual soil grains. Rims on lunar soil grains are highly complex and span the range between erosional surfaces modified by solar wind irradiation to depositional surfaces modified by the condensation of sputtered ions and impact-generated vapors. The optical effects of space weathering effects are directly linked to the production of nanophase Fe metal in lunar materials]. The size of distribution of nanophase inclusions in the rims directly affect optical properties given that large Fe(sup o) grains (approx 10 nm and larger) darken the sample (lower albedo) while the tiny Fe(sup o) grains (<5nm) are the primary agent in spectral "reddening". More recent work has focused on the nature and abundance of OH/H2O in the lunar regolith using orbital data and samples analyses. Advances in sample preparation techniques have made possible detailed analyses of patina-coated rock surfaces. Major advances are occurring in quantifying the rates and efficiency of space weathering processes through laboratory experimentation.

Geochemical exploration for mineralized breccia pipes in northern Arizona, U.S.A.

USGS Publications Warehouse

Wenrich, K.J.

1986-01-01

Thousands of solution-collapse breccia pipe crop out in the canyons and on the plateaus of northern Arizona. Over 80 of these are known to contain U or Cu mineralized rock. The high-grade U ore associated with potentially economic concentrations of Ag, Pb, Zn, Cu, Co and Ni in some of these pipes has continued to stimulate mining and exploration activity in northern Arizona, despite periods of depressed U prices. Large expanses of northern Arizona are comprised of undissected high plateaus; recognition of pipes in these areas is particularly important because mining access to the plateaus is far better than to the canyons. The small size of the pipes, generally less than 600 ft (200 m) in diameter, and limited rock outcrop on the plateaus, compounds the recognition problem. Although the breccia pipes, which bottom in the Mississippian Redwall Limestone, are occasionally exposed on the plateaus as circular features, so are unmineralized near-surface collapse features that bottom in the Permian Kaibab and Toroweap Formations. The distinction between these two classes of circular features is critical during exploration for this unique type of U deposit. Various geochemical and geophysical exploration methods have been tested over these classes of collapse features. Because of the small size of the deposits, and the low-level geochemical signatures in the overlying rock that are rarely dispersed for distances in excess of several hundred feet, most reconnaissance geochemical surveys, such as hydrogeochemistry or stream sediment, will not delineete mineralized pipes. Several types of detailed geochemical surveys made over collapse features, located through examination of aerial photographs and later field mapping, have been successful at delineating collapse features from the surrounding host rock: (1) Rock geochemistry commonly shows low level Ag, As, Ba, Co, Cu, Ni, Pb, Se and Zn anomalies over mineralized breccia pipes; (2) Soil surveys appear to have the greatest potential for distinguishing mineralized breccia pipes from the surrounding terrane. Although the soil anomalies are only twice the background concentrations for most anomalous elements, traverses made over collapse features show consistent enrichment inside of the feature as compared to outside; (3) B. Cereus surveys over a known mineralized pipe show significantly more anomalous samples collected from within the ring fracture than from outside of the breccia pipe; (4) Helium soil-gas surveys were made over 7 collapse features with discouraging results from 5 of the 7 features. Geophysical surveys indicate that scaler audio-magnetotelluric (AMT) and E-field telluric profile data show diagnostic conductivity differences over mineralized pipes as compared to the surrounding terrane. These surveys, coupled with the geochemical surveys conducted as detailed studies over features mapped by field and aerial photograph examination, can be a significant asset in the selection of potential breccia pipes for drilling. ?? 1986.

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

USGS Publications Warehouse

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

2010-01-01

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

Preliminary Map of Potentially Karstic Carbonate Rocks in the Central and Southern Appalachian States

USGS Publications Warehouse

Weary, David J.

2008-01-01

Karst is a landscape produced by dissolution of rocks and the development of integrated subterranean drainages dominated by the flow of ground water in solutionally enlarged conduits. Karst landscapes typically include cave entrances, sinkholes, blind valleys, losing streams, springs, and large and small-scale solution features on bedrock surfaces. Water-bearing rocks beneath the surface containing solutionally enlarged pores, fractures, or conduits are referred to as karst aquifers. About 40 percent of all ground water extracted in the United States comes from karst aquifers (Karst Waters Institute). Karst means many things to many people. To most cavers and many speleologists, karst means areas containing caves. To engineers, home builders, local governments, and insurance companies, karst is exemplified by the occurrence of sinkholes and subsidence hazard. To hydrologists, well drillers, and environmental consultants, the focus on karst may be more limited to karst aquifers and springs. Precise figures are not available, but ground collapses in karst areas in the United States require hundreds of millions of dollars in repair and mitigation costs each year. Most karst in the United States is formed in either carbonate or evaporite rocks. This map depicts only areas of carbonate rock outcrop, the chief host for karst formation in the eastern United States. The U.S. Geological Survey (USGS), in cooperation with the National Cave and Karst Research Institute (NCKRI), the National Speleological Society (NSS), and various State geological surveys, is working on a new national karst map that will delineate areas of karst and karst-like features nationwide. This product attempts to identify potentially karstic areas of the Appalachian states as defined by the Appalachian Regional Commission (ARC), with the addition of the state of Delaware. This map is labeled preliminary because there is an expectation that it will be revised and updated as part of a new national karst map.

Forensic analysis of rockfall scars

NASA Astrophysics Data System (ADS)

de Vilder, Saskia J.; Rosser, Nick J.; Brain, Matthew J.

2017-10-01

We characterise and analyse the detachment (scar) surfaces of rockfalls to understand the mechanisms that underpin their failure. Rockfall scars are variously weathered and comprised of both discontinuity release surfaces and surfaces indicative of fracturing through zones of previously intact rock, known as rock bridges. The presence of rock bridges and pre-existing discontinuities is challenging to quantify due to the difficulty in determining discontinuity persistence below the surface of a rock slope. Rock bridges form an important control in holding blocks onto rockslopes, with their frequency, extent and location commonly modelled from the surface exposure of daylighting discontinuities. We explore an alternative approach to assessing their role, by characterising failure scars. We analyse a database of multiple rockfall scar surfaces detailing the areal extent, shape, and location of broken rock bridges and weathered surfaces. Terrestrial laser scanning and gigapixel imagery were combined to record the detailed texture and surface morphology. From this, scar surfaces were mapped via automated classification based on RGB pixel values. Our analysis of the resulting data from scars on the North Yorkshire coast (UK) indicates a wide variation in both weathering and rock bridge properties, controlled by lithology and associated rock mass structure. Importantly, the proportion of rock bridges in a rockfall failure surface does not increase with failure size. Rather larger failures display fracturing through multiple rock bridges, and in contrast smaller failures fracture occurs only through a single critical rock bridge. This holds implications for how failure mechanisms change with rockfall size and shape. Additionally, the location of rock bridges with respect to the geometry of an incipient rockfall is shown to determine failure mode. Weathering can occur both along discontinuity surfaces and previously broken rock bridges, indicating the sequential stages of progressively detaching rockfall. Our findings have wider implications for hazard assessment where rock slope stability is dependent on the nature of rock bridges, how this is accounted for in slope stability modelling, and the implications of rock bridges on long-term rock slope evolution.

Feature highlighting enhances learning of a complex natural-science category.

PubMed

Miyatsu, Toshiya; Gouravajhala, Reshma; Nosofsky, Robert M; McDaniel, Mark A

2018-04-26

Learning naturalistic categories, which tend to have fuzzy boundaries and vary on many dimensions, can often be harder than learning well defined categories. One method for facilitating the category learning of naturalistic stimuli may be to provide explicit feature descriptions that highlight the characteristic features of each category. Although this method is commonly used in textbooks and classrooms, theoretically it remains uncertain whether feature descriptions should advantage learning complex natural-science categories. In three experiments, participants were trained on 12 categories of rocks, either without or with a brief description highlighting key features of each category. After training, they were tested on their ability to categorize both old and new rocks from each of the categories. Providing feature descriptions as a caption under a rock image failed to improve category learning relative to providing only the rock image with its category label (Experiment 1). However, when these same feature descriptions were presented such that they were explicitly linked to the relevant parts of the rock image (feature highlighting), participants showed significantly higher performance on both immediate generalization to new rocks (Experiment 2) and generalization after a 2-day delay (Experiment 3). Theoretical and practical implications are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Evaporite-karst problems and studies in the USA

USGS Publications Warehouse

Johnson, K.S.

2008-01-01

Evaporites, including rock salt (halite) and gypsum (or anhydrite), are the most soluble among common rocks; they dissolve readily to form the same types of karst features that commonly are found in limestones and dolomites. Evaporites are present in 32 of the 48 contiguous states in USA, and they underlie about 40% of the land area. Typical evaporite-karst features observed in outcrops include sinkholes, caves, disappearing streams, and springs, whereas other evidence of active evaporite karst includes surface-collapse structures and saline springs or saline plumes that result from salt dissolution. Many evaporites also contain evidence of paleokarst, such as dissolution breccias, breccia pipes, slumped beds, and collapse structures. All these natural karst phenomena can be sources of engineering or environmental problems. Dangerous sinkholes and caves can form rapidly in evaporite rocks, or pre-existing karst features can be reactivated and open up (collapse) under certain hydrologic conditions or when the land is put to new uses. Many karst features also propagate upward through overlying surficial deposits. Human activities also have caused development of evaporite karst, primarily in salt deposits. Boreholes (petroleum tests or solution-mining operations) or underground mines may enable unsaturated water to flow through or against salt deposits, either intentionally or accidentally, thus allowing development of small to large dissolution cavities. If the dissolution cavity is large enough and shallow enough, successive roof failures can cause land subsidence and/or catastrophic collapse. Evaporite karst, natural and human-induced, is far more prevalent than is commonly believed. ?? 2007 Springer-Verlag.

Tectonic constraints on a deep-seated rock slide in weathered crystalline rocks

NASA Astrophysics Data System (ADS)

Borrelli, Luigi; Gullà, Giovanni

2017-08-01

Deep-seated rock slides (DSRSs), recognised as one of the most important mass wasting processes worldwide, involve large areas and cause several consequences in terms of environmental and economic damage; they result from a complex of controlling features and processes. DSRSs are common in Calabria (southern Italy) where the complex geo-structural setting plays a key role in controlling the geometry of the failure surface and its development. This paper describes an integrated multi-disciplinary approach to investigate a DSRS in Palaeozoic high-grade metamorphic rocks of the Sila Massif; it focuses on the definition of the internal structure and the predisposing factors of the Serra di Buda landslide near the town of Acri, which is a paradigm for numerous landslides in this area. An integrated interdisciplinary study based on geological, structural, and geomorphological investigations-including field observations of weathering grade of rocks, minero-petrographic characterisations, geotechnical investigations and, in particular, fifteen years of displacement monitoring-is presented. Stereoscopic analysis of aerial photographs and field observations indicate that the Serra di Buda landslide consists of two distinct compounded bodies: (i) an older and dormant body ( 7 ha) and (ii) a more recent and active body ( 13 ha) that overlies the previous one. The active landslide shows movement linked to a deep-seated translational rock slide (block slide); the velocity scale ranges from slow (1.6 m/year during paroxysmal stages) to extremely slow (< 16 mm/year during stable creep stages). The geological structures and rock weathering have played a key role in the landslide's initiation and further development. Steep slope angles, rugged topography, river deepening and erosion at the toe of the slope are also responsible for the formation of this landslide. In particular, the landslide shows a strongly tectonic constraint: the flanks are bounded by high-angle faults, and the main basal failure surface developed inside an E-W southward-dipping thrust fault zone. The entire active rock mass (total volume of approximately 6 Mm3) slid at one time on a failure surface that dipped < 27°, and the maximum depth, as determined by inclinometer measurements, was approximately 58 m. Petrographic and mineralogical analyses suggest that the rocks in the thrust zones, where the failure surfaces develop, are highly affected by weathering processes that significantly reduce the rock strength and facilitate the extensive failure of the Serra di Buda landslide. Finally, the landslide's internal structure, according to geotechnical investigations and displacement monitoring, is proposed. The proposed approach and the obtained results can be generalised to typify other deep landslides in similar geological settings.

Geologic map of Lake Mead and surrounding regions, southern Nevada, southwestern Utah, and northwestern Arizona

USGS Publications Warehouse

Felger, Tracey J.; Beard, Sue

2010-01-01

Regional stratigraphic units and structural features of the Lake Mead region are presented as a 1:250,000 scale map, and as a Geographic Information System database. The map, which was compiled from existing geologic maps of various scales, depicts geologic units, bedding and foliation attitudes, faults and folds. Units and structural features were generalized to highlight the regional stratigraphic and tectonic aspects of the geology of the Lake Mead region. This map was prepared in support of the papers presented in this volume, Special Paper 463, as well as to facilitate future investigations in the region. Stratigraphic units exposed within the area record 1800 million years of geologic history and include Proterozoic crystalline rocks, Paleozoic and Mesozoic sedimentary rocks, Mesozoic plutonic rocks, Cenozoic volcanic and intrusive rocks, sedimentary rocks and surfi cial deposits. Following passive margin sedimentation in the Paleozoic and Mesozoic, late Mesozoic (Sevier) thrusting and Late Cretaceous and early Tertiary compression produced major folding, reverse faulting, and thrust faulting in the Basin and Range, and resulted in regional uplift and monoclinal folding in the Colorado Plateau. Cenozoic extensional deformation, accompanied by sedimentation and volcanism, resulted in large-magnitude high- and low-angle normal faulting and strike-slip faulting in the Basin and Range; on the Colorado Plateau, extension produced north-trending high-angle normal faults. The latest history includes integration of the Colorado River system, dissection, development of alluvial fans, extensive pediment surfaces, and young faulting.

Tantalus Fossae

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 25 June 2002) The Science Tantalus Fossae is a set of long valleys on the eastern side of Alba Patera. These valleys are referred to as grabens and are formed by extension of the crust and faulting. When large amounts of pressure or tension are applied to rocks on timescales that are fast enough that the rock cannot respond by deforming, the rock breaks along faults. In the case of a graben, two parallel faults are formed by extension of the crust and the rock in between the faults drops downward into the space created by the extension. Numerous sets of grabens are visible in this THEMIS image, trending from north-northeast to south-southwest. Because the faults defining the graben are formed parallel to the direction of the applied stress, we know that extensional forces were pulling the crust apart in the west-northwest/east-southeast direction. The large number of grabens around Alba Patera is generally believed to be the result of extensional forces associated with the uplift of Alba Patera. Also visible in this image are a series of linearly aligned pits, called a pit chain. The pits are not the result of impact cratering, but are similar to sinkholes on Earth. Sinkholes are typically formed by the removal of rock (commonly limestone) underground by groundwater -- when enough rock is removed, the overlying rock becomes too heavy to be supported, and it collapses, forming a pit. Unlike sinkholes, however, the pit chains near Alba Patera were likely formed when empty underground lava tubes collapsed, accounting for the presence and alignment of many pits. Numerous channel features are also observed in the image, and follow the local topographic slope, which is downhill to the east-southeast. One of these, a long channel in the center of the image, nicely demonstrates the complex relations possible between geologic features. The geologist's rule of superposition says that a feature on top of (superposing) another feature, or cutting across another feature is younger than the feature it covers or cuts. In one location, the channel cuts across the somewhat subdued fault defining a graben (near the right side of the image), indicating that the channel was carved after the graben was formed. But in other places (near the center of the image), the channel is clearly cut by a large fault defining one of the grabens, indicating that some faulting was occurring after the channel was carved. These relationships can be observed throughout this image. By mapping out superposition relationships in detail, geologists can establish a complex sequence of events that occurred long ago. The Story The first thing that catches your eye in the image above is a string of round pits that are strewn dramatically on the surface. Although they may look like craters, nothing came hurtling in from the sky to make them. Instead, collapses along a lava tube have created this long dotted line on the Martian surface. The lava tube, a hollow feature beneath the surface, can't always withstand the weight from above, and so collapses in places, forming pits like the ones seen here. Throughout the rest of the image are a series of depressed valleys known as grabens that run roughly from the northeast to the southwest. They formed when the crust of the Martian surface was stretched so fast that it broke along faults. When that happened, the rock in between fell downward into the space created by the extension, creating the long subtle streaks of lowered terrain. They were probably created when Alba Patera, the shield volcano of this area, was elevated or 'uplifted' through tectonic forces. This area of long valleys is named after Tantalus, a king of ancient Lydia who, according to legend, betrayed the gods and was sent to Hades. In this subterranean place, he was forced to stand in water up to his chin underneath the branches of fruit trees. Every time he tried to drink, the water would recede, and every time he tried to eat, the boughs would move the fruit just out of reach. You can easily see where the word 'tantalize' comes from. Scientists are intrigued so much by the history of this area that they seek to understand its elusive past. Luckily, their interests are much more in reach than those of poor Tantalus. A number of channels in this image (running downhill from the west-northwest to the east-southeast) help them understand the chain of events that worked to create the compelling features in this region. Take a look at the channels close-up and see if you can tell whether the channels or the grabens happened first. A rule of thumb is that if one feature is on top of another or cuts across it, it is younger than the feature it covers or cuts. One of the channels in the center of the image is great to study. Toward the right side of the image, the channel cuts across a fault, indicating it formed before the graben. Follow the channel westward, however, and you'll see that a large fault cuts the channel, indicating that this graben formed after the channel. That probably means this criss-crossed region went through a seeming eternity of torture itself, as the land kept tearing and stretching, as channels were carved and recarved, as lava tubes formed and then finally collapsed, only to have their walls erode in further streaks as well.

The surface orientation of some Apollo 14 rocks.

NASA Technical Reports Server (NTRS)

Hoerz, F.; Morrison, D. A.; Hartung, J. B.

1972-01-01

Detailed stereomicroscopic studies of the distribution of microcraters, soil covers, and glass coatings were performed to reconstruct the most recent surface orientations of selected Apollo 14 rocks. Surface orientations could be established for rocks 14053, 14073, 14301, 14303, 14307, 14310, and 14311 (which includes rock 14308). A tentative orientation of rock 14055 is suggested, and comments concerning the surface history of rocks 14302, 14305, and 14318 are presented. The examination of rocks 14066, 14306, and 14321 indicates that these specimens have complicated surface histories that prevent reconstruction of their orientation by the criteria that were established in these stereomicroscopic studies.

Igneous rocks formed by hypervelocity impact

NASA Astrophysics Data System (ADS)

Osinski, Gordon R.; Grieve, Richard A. F.; Bleacher, Jacob E.; Neish, Catherine D.; Pilles, Eric A.; Tornabene, Livio L.

2018-03-01

Igneous rocks are the primary building blocks of planetary crusts. Most igneous rocks originate via decompression melting and/or wet melting of protolith lithologies within planetary interiors and their classification and compositional, petrographic, and textural characteristics, are well-studied. As our exploration of the Solar System continues, so too does the inventory of intrusive and extrusive igneous rocks, settings, and processes. The results of planetary exploration have also clearly demonstrated that impact cratering is a ubiquitous geological process that has affected, and will continue to affect, all planetary objects with a solid surface, whether that be rock or ice. It is now recognized that the production of igneous rocks is a fundamental outcome of hypervelocity impact. The goal of this review is to provide an up-to-date synthesis of our knowledge and understanding of igneous rocks formed by hypervelocity impact. Following a brief overview of the basics of the impact process, we describe how and why melts are generated during impact events and how impact melting differs from endogenic igneous processes. While the process may differ, we show that the products of hypervelocity impact can share close similarities with volcanic and shallow intrusive igneous rocks of endogenic origin. Such impact melt rocks, as they are termed, can display lobate margins and cooling cracks, columnar joints and at the hand specimen and microscopic scale, such rocks can display mineral textures that are typical of volcanic rocks, such as quench crystallites, ophitic, porphyritic, as well as features such as vesicles, flow textures, and so on. Historically, these similarities led to the misidentification of some igneous rocks now known to be impact melt rocks as being of endogenic origin. This raises the question as to how to distinguish between an impact versus an endogenic origin for igneous-like rocks on other planetary bodies where fieldwork and sample analysis may not be possible and all that may be available is remote sensing data. While the interpretation of some impact melt rocks may be relatively straightforward (e.g., for clast-rich varieties and those with clear projectile contamination) we conclude that distinguishing between impact and endogenic igneous rocks is a non-trivial task that ultimately may require sample investigation and analysis to be conducted. Caution is, therefore, urged in the interpretation of igneous rocks on planetary surfaces.

Desert pavement study at Amboy, California

NASA Technical Reports Server (NTRS)

Williams, S.; Greeley, R.

1984-01-01

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

Coupling photogrammetric data with DFN-DEM model for rock slope hazard assessment

NASA Astrophysics Data System (ADS)

Donze, Frederic; Scholtes, Luc; Bonilla-Sierra, Viviana; Elmouttie, Marc

2013-04-01

Structural and mechanical analyses of rock mass are key components for rock slope stability assessment. The complementary use of photogrammetric techniques [Poropat, 2001] and coupled DFN-DEM models [Harthong et al., 2012] provides a methodology that can be applied to complex 3D configurations. DFN-DEM formulation [Scholtès & Donzé, 2012a,b] has been chosen for modeling since it can explicitly take into account the fracture sets. Analyses conducted in 3D can produce very complex and unintuitive failure mechanisms. Therefore, a modeling strategy must be established in order to identify the key features which control the stability. For this purpose, a realistic case is presented to show the overall methodology from the photogrammetry acquisition to the mechanical modeling. By combining Sirovision and YADE Open DEM [Kozicki & Donzé, 2008, 2009], it can be shown that even for large camera to rock slope ranges (tested about one kilometer), the accuracy of the data are sufficient to assess the role of the structures on the stability of a jointed rock slope. In this case, on site stereo pairs of 2D images were taken to create 3D surface models. Then, digital identification of structural features on the unstable block zone was processed with Sirojoint software [Sirovision, 2010]. After acquiring the numerical topography, the 3D digitalized and meshed surface was imported into the YADE Open DEM platform to define the studied rock mass as a closed (manifold) volume to define the bounding volume for numerical modeling. The discontinuities were then imported as meshed planar elliptic surfaces into the model. The model was then submitted to gravity loading. During this step, high values of cohesion were assigned to the discontinuities in order to avoid failure or block displacements triggered by inertial effects. To assess the respective role of the pre-existing discontinuities in the block stability, different configurations have been tested as well as different degree of fracture persistency in order to enhance the possible contribution of rock bridges on the failure surface development. It is believed that the proposed methodology can bring valuable complementary information for rock slope stability analysis in presence of complex fractured system for which classical "Factor of Safety" is difficult to express. References • Harthong B., Scholtès L. & F.V. Donzé, Strength characterization of rock masses, using a coupled DEM-DFN model, Geophysical Journal International, doi: 10.1111/j.1365-246X.2012.05642.x, 2012. • Kozicki J & Donzé FV. YADE-OPEN DEM: an open--source software using a discrete element method to simulate granular material, Engineering Computations, 26(7):786-805, 2009 • Kozicki J, Donzé FV. A new open-source software developed for numerical simulations using discrete modeling methods, Comp. Meth. In Appl. Mech. And Eng. 197:4429-4443, 2008. • Poropat, G.V., New methods for mapping the structure of rock masses. In Proceedings, Explo 2001, Hunter Valley, New South Wales, 28-31 October 2001, pp. 253-260, 2001. • Scholtès, L. & Donzé FV. Modelling progressive failure in fractured rock masses using a 3D discrete element method, International Journal of Rock Mechanics and Mining Sciences, 52:18-30, 2012a. • Scholtès, L. & Donzé, F.-V., DEM model for soft and hard rocks: role of grain interlocking on strength, J. Mech. Phys. Solids, doi: 10.1016/j.jmps.2012.10.005, 2012b. • Sirovision, Commonwealth Scientific and Industrial Research Organisation CSIRO, Siro3D Sirovision 3D Imaging Mapping System Manual Version 4.1, 2010

Karst in the United States: a digital map compilation and database

USGS Publications Warehouse

Weary, David J.; Doctor, Daniel H.

2014-01-01

This report describes new digital maps delineating areas of the United States, including Puerto Rico and the U.S. Virgin Islands, having karst or the potential for development of karst and pseudokarst. These maps show areas underlain by soluble rocks and also by volcanic rocks, sedimentary deposits, and permafrost that have potential for karst or pseudokarst development. All 50 States contain rocks with potential for karst development, and about 18 percent of their area is underlain by soluble rocks having karst or the potential for development of karst features. The areas of soluble rocks shown are based primarily on selection from State geologic maps of rock units containing significant amounts of carbonate or evaporite minerals. Areas underlain by soluble rocks are further classified by general climate setting, degree of induration, and degree of exposure. Areas having potential for volcanic pseudokarst are those underlain chiefly by basaltic-flow rocks no older than Miocene in age. Areas with potential for pseudokarst features in sedimentary rocks are in relatively unconsolidated rocks from which pseudokarst features, such as piping caves, have been reported. Areas having potential for development of thermokarst features, mapped exclusively in Alaska, contain permafrost in relatively thick surficial deposits containing ground ice. This report includes a GIS database with links from the map unit polygons to online geologic unit descriptions.

Ganymede G1 & G2 Encounters - Interior of Ganymede

NASA Image and Video Library

1997-12-16

NASA's Voyager images are used to create a global view of Ganymede. The cut-out reveals the interior structure of this icy moon. This structure consists of four layers based on measurements of Ganymede's gravity field and theoretical analyses using Ganymede's known mass, size and density. Ganymede's surface is rich in water ice and Voyager and Galileo images show features which are evidence of geological and tectonic disruption of the surface in the past. As with the Earth, these geological features reflect forces and processes deep within Ganymede's interior. Based on geochemical and geophysical models, scientists expected Ganymede's interior to either consist of: a) an undifferentiated mixture of rock and ice or b) a differentiated structure with a large lunar sized "core" of rock and possibly iron overlain by a deep layer of warm soft ice capped by a thin cold rigid ice crust. Galileo's measurement of Ganymede's gravity field during its first and second encounters with the huge moon have basically confirmed the differentiated model and allowed scientists to estimate the size of these layers more accurately. In addition the data strongly suggest that a dense metallic core exists at the center of the rock core. This metallic core suggests a greater degree of heating at sometime in Ganymede's past than had been proposed before and may be the source of Ganymede's magnetic field discovered by Galileo's space physics experiments. http://photojournal.jpl.nasa.gov/catalog/PIA00519

Discovery of columnar jointing on Mars

USGS Publications Warehouse

Milazzo, M.P.; Keszthelyi, L.P.; Jaeger, W.L.; Rosiek, M.; Mattson, S.; Verba, C.; Beyer, R.A.; Geissler, P.E.; McEwen, A.S.

2009-01-01

We report on the discovery of columnar jointing in Marte Valles, Mars. These columnar lavas were discovered in the wall of a pristine, 16-km-diameter impact crater and exhibit the features of terrestrial columnar basalts. There are discontinuous outcrops along the entire crater wall, suggesting that the columnar rocks covered a surface area of at least 200 km2, assuming that the rocks obliterated by the impact event were similarly jointed. We also see columns in the walls of other fresh craters in the nearby volcanic plains of Elysium Planitia-Amazonis Planitia, which include Marte Vallis, and in a well-preserved crater in northeast Hellas. ?? 2009 The Geological Society of America.

The discovery of columnar jointing on Mars

USGS Publications Warehouse

Milazzo, M.P.; Keszthelyi, L.P.; Jaeger, W.L.; Rosiek, M.; Mattson, S.; Verba, C.; Beyer, R.A.; Geissler, P.E.; McEwen, A.S.; ,

2009-01-01

We report on the discovery of columnar jointing in Marte Valles, Mars. These columnar lavas were discovered in the wall of a pristine, 16-km-diameter impact crater and exhibit the features of terrestrial columnar basalts. There are discontinuous outcrops along the entire crater wall, suggesting that the columnar rocks covered a surface area of at least 200 km2, assuming that the rocks obliterated by the impact event were similarly jointed. We also see columns in the walls of other fresh craters in the nearby volcanic plains of Elysium Planitia–Amazonis Planitia, which include Marte Vallis, and in a well-preserved crater in northeast Hellas.

A low temperature transfer of ALH84001 from Mars to Earth.

PubMed

Weiss, B P; Kirschvink, J L; Baudenbacher, F J; Vali, H; Peters, N T; Macdonald, F A; Wikswo, J P

2000-10-27

The ejection of material from Mars is thought to be caused by large impacts that would heat much of the ejecta to high temperatures. Images of the magnetic field of martian meteorite ALH84001 reveal a spatially heterogeneous pattern of magnetization associated with fractures and rock fragments. Heating the meteorite to 40 degrees C reduces the intensity of some magnetic features, indicating that the interior of the rock has not been above this temperature since before its ejection from the surface of Mars. Because this temperature cannot sterilize most bacteria or eukarya, these data support the hypothesis that meteorites could transfer life between planets in the solar system.

Camera, Hand Lens, and Microscope Probe (CHAMP): An Instrument Proposed for the 2009 MSL Rover Mission

NASA Technical Reports Server (NTRS)

Mungas, Greg S.; Beegle, Luther W.; Boynton, John E.; Lee, Pascal; Shidemantle, Ritch; Fisher, Ted

2004-01-01

The Camera, Hand Lens, and Microscope Probe (CHAMP) will allow examination of martian surface features and materials (terrain, rocks, soils, samples) on spatial scales ranging from kilometers to micrometers, thus enabling both microscopy and context imaging with high operational flexibility. CHAMP is designed to allow the detailed and quantitative investigation of a wide range of geologic features and processes on Mars, leading to a better quantitative understanding of the evolution of the martian surface environment through time. In particular, CHAMP will provide key data that will help understand the local region explored by Mars Surface Laboratory (MSL) as a potential habitat for life. CHAMP will also support other anticipated MSL investigations, in particular by helping identify and select the highest priority targets for sample collection and analysis by the MSL's analytical suite.

Hematite on the Surface of Meridiani Planum and Gusev Crater

NASA Technical Reports Server (NTRS)

Brueckner, J.; Dreibus, G.; Jagoutz, E.; Gellert, R.; Lugmair, G.; Rieder, R.; Waenke, H.; Zipfel, J.; Klingelhoefer, G.; Clark, B. C.

2005-01-01

Meridiani Planum was selected as a landing side for the Rover Opportunity because of an indication of hematite observed from orbit. Meridiani Planum consists of sorted sands with aeolian features like ripples and desert pavements. In impact craters, a high-albedo layered bedrock is exposed. The soil is a mixture of: (i) fine sand material in the size ranges of 50 to 150 m, (ii) sub-angular, irregular particles of 0.5 to 5 mm size with submillimeter circular voids that are most likely vesicular basaltic fragments, and (iii) spherules with a restricted grain size between 4 and 6 mm. The Mini-TES on board the rover Opportunity identified a hematite signature at distance resulting from mm-sized spherules as determined by the Moussbauer Spectrometer. Small quantities of similar spherules (2 vol. %) were found in rock exposures in Eagle crater and were interpreted as concretions that formed by precipitation from aqueous fluids inside sedimentary rocks. At Gusev crater no hematite was observed until sol 90 except for layering on a rock. Our investigations of hematite bearing materials, measured by the Alpha Particle X-ray Spectrometer (APXS), Moussbauer Spectrometer (MB), and Microscopic Imager (MI), provide a more integrated view of different occurrences of hematite on the martian surface. Chemistry of soils and rocks: Chemical compositions

Geology and ground-water resources of Rock County, Wisconsin

USGS Publications Warehouse

LeRoux, E.F.

1964-01-01

Rock County is in south-central Wisconsin adjacent to the Illinois State line. The county has an area of about 723 square miles and had a population of about 113,000 in 1957 ; it is one of the leading agricultural and industrial counties in the State. The total annual precipitation averages about 32 inches, and the mean annual temperature is about 48 ? F. Land-surface altitudes are generally between 800 and 00 feet, but range from 731 feet, where the Rock River flows into Illinois, to above 1,080 feet, at several places in the northwestern part of the county. The northern part of Rock County consists of the hills and kettles of a terminal moraine which slopes southward to a flat, undissected outwash plain. The southeastern part of the county is an area of gentle slopes, whereas the southwestern part consists of steep-sided valleys and ridges. Rock County is within the drainage basin of the Rock River, which flows southward through the center of the county. The western and southwestern parts of ,the county are drained by the Sugar River und Coon Creek, both of which flow into the Pecatonica River in Illinois and thence into the Rock River. The southeastern part of the county is drained by Turtle Creek, which also flows into Illinois before joining the Rock River. Nearly all the lakes and ponds are in the northern one-third of the county, the area of most recent glaciation. The aquifers in Rock County are of sedimentary origin and include deeply buried sandstones, shales, and dolomites of the Upper Cambrian series. This series overlies crystalline rocks of Precambrian age and supplies water to all the cities and villages in the county. The St. Peter sandstone of Ordovician age underlies all Rock County except where the formation has been removed by erosion in the Rock and Sugar River valleys, and perhaps in Coon Creek valley. The St. Peter sandstone is the principal source of water for domestic, stock, and small industrial wells in the western half of the county. This sandstone also yields some water to uncased wells that tap the deeper rocks of the Upper Cambrian series. East of the Rock River the Platteville, Decorah, and Galena formations undifferentiated, or Platteville-Galena unit, is the principal source of water for domestic and stock wells. Unconsolidated deposits of glacial origin cover most of Rock County and supply water to many small wells. In the outwash deposits along the Rock River, wells of extremely high capacity have been developed for industrial and municipal use. The most significant feature of the bedrock surface in Rock County is the ancestral Rock River valley, which has been filled with glacial outwash to a depth of at least 396 feet below the present land surface. East of the buried valley the bedrock has a fiat, relatively undissected surface. West of the valley the bedrock surface is rugged and greatly dissected. Ground water in Rock County occurs under both water-table and artesian conditions; however, because of the interconnection and close relation of all ground water in the county, the entire system is considered to be a single groundwater body whose surface may be represented by one piezometric map. Recharge occurs locally, throughout the county. Nearly all recharge is derived directly from precipitation that percolates downward to become a part of the groundwater body. Natural movement of water in the consolidated water-bearing units is generally toward the buried Rock and Sugar River valleys. Movement of water in the sandstones of Cambrian age was calculated to be about 44 million gallons a day toward the Rock River. Discharge from wells in Rock County in 1957 was about 23 million gallons a day. Nearly 90 percent of this water was drawn from the area along the Rock River. Drilled wells, most of which were drilled by the cable-tool method, range in diameter from 3 to 26 inches, and in depth from 46 to 1,225 feet. Driven wells in alluvium and glacial drift are usually 1? to 2? in

Mapping the mineralogy and lithology of Canyonlands, Utah with imaging spectrometer data and the multiple spectral feature mapping algorithm

NASA Technical Reports Server (NTRS)

Clark, Roger N.; Swayze, Gregg A.; Gallagher, Andrea

1992-01-01

The sedimentary sections exposed in the Canyonlands and Arches National Parks region of Utah (generally referred to as 'Canyonlands') consist of sandstones, shales, limestones, and conglomerates. Reflectance spectra of weathered surfaces of rocks from these areas show two components: (1) variations in spectrally detectable mineralogy, and (2) variations in the relative ratios of the absorption bands between minerals. Both types of information can be used together to map each major lithology and the Clark spectral features mapping algorithm is applied to do the job.

Mapping alpha-Particle X-Ray Fluorescence Spectrometer (Map-X)

NASA Technical Reports Server (NTRS)

Blake, D. F.; Sarrazin, P.; Bristow, T.

2014-01-01

Many planetary surface processes (like physical and chemical weathering, water activity, diagenesis, low-temperature or impact metamorphism, and biogenic activity) leave traces of their actions as features in the size range 10s to 100s of micron. The Mapping alpha-particle X-ray Spectrometer ("Map-X") is intended to provide chemical imaging at 2 orders of magnitude higher spatial resolution than previously flown instruments, yielding elemental chemistry at or below the scale length where many relict physical, chemical, and biological features can be imaged and interpreted in ancient rocks.

Searching the Sinus Amoris: Using profiles of geological units, impact and volcanic features to characterize a major terrane interface on the Moon

NASA Technical Reports Server (NTRS)

Clark, P.; Joerg, S.; Dehon, R.

1994-01-01

Geochemical profiles of surface units, impact, and volcanic features are studied in detail to determine the underlying structure in an area of extensive mare/highland interface, Sinus Amoris. This study region includes and surrounds the northeastern embayment of Mare Tranquillitatis. The concentrations of two major rock-forming elements (Mg and Al), which were derived from the Apollo 15 orbital geochemical measurements, were used in this study. Mapped units and deposits associated with craters in the northwestern part of the region tend to have correlated low Mg and Al concentrations, indicating the presence of Potassium (K)-Rare Earth Elements (REE)-Phosphorus (P) (KREEP)-enriched basalt. Found along the northeastern rim of Tranquillitatis were areas with correlated high Mg and Al concentration, indicating the presence of troctolite. Distinctive west/east and north/south trends were observed in the concentrations of Mg and Al, and, by implication, in the distribution of major rock components on the surface. Evidence for a systematic geochemical transition in highland or basin-forming units may be observed here in the form of distinctive differences in chemistry in otherwise similar units in the western and eastern portions of the study region.

Forensic Excavation of Rock Masses: A Technique to Investigate Discontinuity Persistence

NASA Astrophysics Data System (ADS)

Shang, J.; Hencher, S. R.; West, L. J.; Handley, K.

2017-11-01

True persistence of rock discontinuities (areas with insignificant tensile strength) is an important factor controlling the engineering behaviour of fractured rock masses, but is extremely difficult to quantify using current geological survey methodologies, even where there is good rock exposure. Trace length as measured in the field or using remote measurement devices is actually only broadly indicative of persistence for rock engineering practice and numerical modelling. Visible traces of discontinuities are treated as if they were open fractures within rock mass classifications, despite many such traces being non-persistent and actually retaining considerable strength. The common assumption of 100% persistence, based on trace length, is generally extremely conservative in terms of strength and stiffness, but not always so and may lead to a wrong prediction of failure mechanism or of excavatability. Assuming full persistence would give hopelessly incorrect predictions of hydraulic conductivity. A new technique termed forensic excavation of rock masses is introduced, as a procedure for directly investigating discontinuity persistence. This technique involves non-explosive excavation of rock masses by injecting an expansive chemical splitter along incipient discontinuities. On expansion, the splitter causes the incipient traces to open as true joints. Experiments are described in which near-planar rock discontinuities, through siltstone and sandstone, were opened up by injecting the splitter into holes drilled along the lines of visible traces of the discontinuities in the laboratory and in the field. Once exposed the surfaces were examined to investigate the pre-existing persistence characteristics of the incipient discontinuities. One conclusion from this study is that visible trace length of a discontinuity can be a poor indicator of true persistence (defined for a fracture area with negligible tensile strength). An observation from this series of experiments was that freshly failed surfaces through pre-existing rock bridges were relatively rough compared to sections of pre-existing weaker areas of geologically developed (though still incipient) discontinuities. Fractographic features such as hackle and rib marks were typical of the freshly broken rock bridges, whereas opened-up areas of incipient discontinuity were smoother. Schmidt hammer rebound values were generally higher for the rock bridge areas, probably reflecting their lower degree of chemical and physical weathering.

Odyssey/White Rock

NASA Technical Reports Server (NTRS)

2002-01-01

These Mars Odyssey images show the 'White Rock' feature on Mars in both infrared (left) and visible (right) wavelengths. The images were acquired simultaneously on March 11, 2002. The box shows where the visible image is located in the infrared image. 'White Rock' is the unofficial name for this unusual landform that was first observed during the Mariner 9 mission in the early 1970's. The variations in brightness in the infrared image are due to differences in surface temperature, where dark is cool and bright is warm. The dramatic differences between the infrared and visible views of White Rock are the result of solar heating. The relatively bright surfaces observed at visible wavelengths reflect more solar energy than the darker surfaces, allowing them to stay cooler and thus they appear dark in the infrared image. The new thermal emission imaging system data will help to address the long standing question of whether the White Rock deposit was produced in an ancient crater lake or by dry processes of volcanic or wind deposition. The infrared image has a resolution of 100 meters (328 feet) per pixel and is 32 kilometers (20 miles) wide. The visible image has a resolution of 18 meters per pixel and is approximately 18 kilometers (11 miles) wide. The images are centered at 8.2 degrees south latitude and 24.9 degrees east longitude.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

The Rio Tinto Basin, Spain: Mineralogy, Sedimentary Geobiology, and Implications for Interpretation of Outcrop Rocks at Meridiani Planum, Mars

NASA Technical Reports Server (NTRS)

Fernandez-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H.

2005-01-01

Exploration by the NASA rover Opportunity has revealed sulfate- and hematite-rich sedimentary rocks exposed in craters and other surface features of Meridiani Planum, Mars. Modern, Holocene, and Plio-Pleistocene deposits of the Rio Tinto, southwestern Spain, provide at least a partial environmental analog to Meridiani Planum rocks, facilitating our understanding of Meridiani mineral precipitation and diagenesis, while informing considerations of martian astrobiology. Oxidation, thought to be biologically mediated, of pyritic ore bodies by groundwaters in the source area of the Rio Tinto generates headwaters enriched in sulfuric acid and ferric iron. Seasonal evaporation of river water drives precipitation of hydronium jarosite and schwertmannite, while (Mg,Al,Fe(sup 3+))-copiapite, coquimbite, gypsum, and other sulfate minerals precipitate nearby as efflorescences where locally variable source waters are brought to the surface by capillary action. During the wet season, hydrolysis of sulfate salts results in the precipitation of nanophase goethite. Holocene and Plio-Pleistocene terraces show increasing goethite crystallinity and then replacement of goethite with hematite through time. Hematite in Meridiani spherules also formed during diagenesis, although whether these replaced precursor goethite or precipitated directly from groundwaters is not known. The retention of jarosite and other soluble sulfate salts suggests that water limited the diagenesis of Meridiani rocks. Diverse prokaryotic and eukaryotic microorganisms inhabit acidic and seasonally dry Rio Tinto environments. Organic matter does not persist in Rio Tinto sediments, but biosignatures imparted to sedimentary rocks as macroscopic textures of coated microbial streamers, surface blisters formed by biogenic gas, and microfossils preserved as casts and molds in iron oxides help to shape strategies for astrobiological investigation of Meridiani outcrops.

Water-Rock Differentiation on Ceres as Derived From Numerical Studies: Late Water Separation and Thick Undifferentiated Crust

NASA Astrophysics Data System (ADS)

Neumann, Wladimir Otto; Breuer, Doris; Spohn, Tilman

2016-10-01

Water-rock separation is a major factor in discriminating between models of Ceres' present-day state. We calculate differentiation models of Ceres to investigate how water-rock separation and convection influence its evolution. We expand on the presence of liquids and the possibility of cryovolcanism in order to explain surface features observed by Dawn[1,2].The model[3] includes accretion, reduction of the dust porosity, latent heat of ice melting, compaction driven water-rock separation, accretional heating, hydrothermal circulation, solid-state convection of ice, and convection in a water ocean.Accretion times considered cover 1-10 Ma rel. to CAIs. Compaction of the dust pores starts with ice at T≈180-240 K and proceeds with rock minerals at temperatures of up to 730 K. Sub-surface remains too cold to close these pores. The water-rock separation proceeds by water percolation in a rock matrix. Differentiation timing depends on the matrix deformation and no differentiation occurs in layers with leftover dust porosity. Compaction takes several hundred million years due to a slow temperature increase. The differentiation is extended according to this time scale even though liquid water is produced early. While the radionuclides are concentrated in the core no heat is produced in the ocean. If convection is neglected, the ocean is heated by the core and cooled through the crust, and remains totally liquid until the present day. Convection keeps the ocean cold and results in a colder present-day crust. Only a thin basal part of the ocean remains liquid, while the upper part freezes.In our models, a water ocean starts forming within 10 Ma after CAIs, but its completion is retarded relative to the melting of ice by up to O(0.1 Ga). The differentiation is partial and a porous outer layer is retained. Present-day temperatures calculated indicate that hydrated salts can be mobile at a depth of ≥1.5-5 km implying buoyancy of ice and salt-enriched crustal reservoirs. The impacts Haulani, Ikapati and Occator may have cut into these reservoirs triggering the mobility that formed cryovolcanic features[1,2].[1] Jaumann R et al. (2016) LPSC XLVII [2] Krohn K et al. (2016) LPSC XLVII. [3] Neumann W et al. (2015) A&A 584: A117.

Innovative Applications of Laser Scanning and Rapid Prototype Printing to Rock Breakdown Experiments

NASA Technical Reports Server (NTRS)

Bourke, Mary; Viles, Heather; Nicoll, Joe; Lyew-Ayee, Parris; Ghent, Rebecca; Holmlund, James

2008-01-01

We present the novel application of two technologies for use in rock breakdown experiments, i.e. close-range, ground-based 3D triangulation scanning and rapid prototype printing. These techniques aid analyses of form-process interactions across the range of scales relevant to breakdown (micron-m). This is achieved through (a) the creation of DEMs (which permit quantitative description and analysis of rock surface morphology and morphological change) and (b) the production of more realistically-shaped experimental blocks. We illustrate the use of these techniques, alongside appropriate data analysis routines, in experiments designed to investigate the persistence of fluvially-derived features in the face of subsequent wind abrasion and weathering. These techniques have a range of potential applications in experimental field and lab-based geomorphic studies beyond those specifically outlined here.

Real-time detection of dielectric anisotropy or isotropy in unconventional oil-gas reservoir rocks supported by the oblique-incidence reflectivity difference technique

NASA Astrophysics Data System (ADS)

Zhan, Honglei; Wang, Jin; Zhao, Kun; Lű, Huibin; Jin, Kuijuan; He, Liping; Yang, Guozhen; Xiao, Lizhi

2016-12-01

Current geological extraction theory and techniques are very limited to adequately characterize the unconventional oil-gas reservoirs because of the considerable complexity of the geological structures. Optical measurement has the advantages of non-interference with the earth magnetic fields, and is often useful in detecting various physical properties. One key parameter that can be detected using optical methods is the dielectric permittivity, which reflects the mineral and organic properties. Here we reported an oblique-incidence reflectivity difference (OIRD) technique that is sensitive to the dielectric and surface properties and can be applied to characterization of reservoir rocks, such as shale and sandstone core samples extracted from subsurface. The layered distribution of the dielectric properties in shales and the uniform distribution in sandstones are clearly identified using the OIRD signals. In shales, the micro-cracks and particle orientation result in directional changes of the dielectric and surface properties, and thus, the isotropy and anisotropy of the rock can be characterized by OIRD. As the dielectric and surface properties are closely related to the hydrocarbon-bearing features in oil-gas reservoirs, we believe that the precise measurement carried with OIRD can help in improving the recovery efficiency in well-drilling process.

Real-time detection of dielectric anisotropy or isotropy in unconventional oil-gas reservoir rocks supported by the oblique-incidence reflectivity difference technique

PubMed Central

Zhan, Honglei; Wang, Jin; Zhao, Kun; Lű, Huibin; Jin, Kuijuan; He, Liping; Yang, Guozhen; Xiao, Lizhi

2016-01-01

Current geological extraction theory and techniques are very limited to adequately characterize the unconventional oil-gas reservoirs because of the considerable complexity of the geological structures. Optical measurement has the advantages of non-interference with the earth magnetic fields, and is often useful in detecting various physical properties. One key parameter that can be detected using optical methods is the dielectric permittivity, which reflects the mineral and organic properties. Here we reported an oblique-incidence reflectivity difference (OIRD) technique that is sensitive to the dielectric and surface properties and can be applied to characterization of reservoir rocks, such as shale and sandstone core samples extracted from subsurface. The layered distribution of the dielectric properties in shales and the uniform distribution in sandstones are clearly identified using the OIRD signals. In shales, the micro-cracks and particle orientation result in directional changes of the dielectric and surface properties, and thus, the isotropy and anisotropy of the rock can be characterized by OIRD. As the dielectric and surface properties are closely related to the hydrocarbon-bearing features in oil-gas reservoirs, we believe that the precise measurement carried with OIRD can help in improving the recovery efficiency in well-drilling process. PMID:27976746

Pluri-decadal (1955-2014) evolution of glacier-rock glacier transitional landforms in the central Andes of Chile (30-33° S)

NASA Astrophysics Data System (ADS)

Monnier, Sébastien; Kinnard, Christophe

2017-08-01

Three glacier-rock glacier transitional landforms in the central Andes of Chile are investigated over the last decades in order to highlight and question the significance of their landscape and flow dynamics. Historical (1955-2000) aerial photos and contemporary (> 2000) Geoeye satellite images were used together with common processing operations, including imagery orthorectification, digital elevation model generation, and image feature tracking. At each site, the rock glacier morphology area, thermokarst area, elevation changes, and horizontal surface displacements were mapped. The evolution of the landforms over the study period is remarkable, with rapid landscape changes, particularly an expansion of rock glacier morphology areas. Elevation changes were heterogeneous, especially in debris-covered glacier areas with large heaving or lowering up to more than ±1 m yr-1. The use of image feature tracking highlighted spatially coherent flow vector patterns over rock glacier areas and, at two of the three sites, their expansion over the studied period; debris-covered glacier areas are characterized by a lack of movement detection and/or chaotic displacement patterns reflecting thermokarst degradation; mean landform displacement speeds ranged between 0.50 and 1.10 m yr-1 and exhibited a decreasing trend over the studied period. One important highlight of this study is that, especially in persisting cold conditions, rock glaciers can develop upward at the expense of debris-covered glaciers. Two of the studied landforms initially (prior to the study period) developed from an alternation between glacial advances and rock glacier development phases. The other landform is a small debris-covered glacier having evolved into a rock glacier over the last half-century. Based on these results it is proposed that morphological and dynamical interactions between glaciers and permafrost and their resulting hybrid landscapes may enhance the resilience of the mountain cryosphere against climate change.

Textural and Mineralogical Analysis of Volcanic Rocks by µ-XRF Mapping.

PubMed

Germinario, Luigi; Cossio, Roberto; Maritan, Lara; Borghi, Alessandro; Mazzoli, Claudio

2016-06-01

In this study, µ-XRF was applied as a novel surface technique for quick acquisition of elemental X-ray maps of rocks, image analysis of which provides quantitative information on texture and rock-forming minerals. Bench-top µ-XRF is cost-effective, fast, and non-destructive, can be applied to both large (up to a few tens of cm) and fragile samples, and yields major and trace element analysis with good sensitivity. Here, X-ray mapping was performed with a resolution of 103.5 µm and spot size of 30 µm over sample areas of about 5×4 cm of Euganean trachyte, a volcanic porphyritic rock from the Euganean Hills (NE Italy) traditionally used in cultural heritage. The relative abundance of phenocrysts and groundmass, as well as the size and shape of the various mineral phases, were obtained from image analysis of the elemental maps. The quantified petrographic features allowed identification of various extraction sites, revealing an objective method for archaeometric provenance studies exploiting µ-XRF imaging.

Rock fracture skeleton tracing by image processing and quantitative analysis by geometry features

NASA Astrophysics Data System (ADS)

Liang, Yanjie

2016-06-01

In rock engineering, fracture measurement is important for many applications. This paper proposes a novel method for rock fracture skeleton tracing and analyzing. As for skeleton localizing, the curvilinear fractures are multiscale enhanced based on a Hessian matrix, after image binarization, and clutters are post-processed by image analysis; subsequently, the fracture skeleton is extracted via ridge detection combined with a distance transform and thinning algorithm, after which gap sewing and burrs removal repair the skeleton. In regard to skeleton analyzing, the roughness and distribution of a fracture network are respectively described by the fractal dimensions D s and D b; the intersection and fragmentation of a fracture network are respectively characterized by the average number of ends and junctions per fracture N average and the average length per fracture L average. Three rock fracture surfaces are analyzed for experiments and the results verify that both the fracture tracing accuracy and the analysis feasibility are satisfactory using the new method.

Geochemistry of surface water in alpine catchments in central Colorado, USA: Resolving host-rock effects at different spatial scales

USGS Publications Warehouse

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

2009-01-01

The US Geological Survey is conducting a study of surface-water quality in the Rocky Mountains of central Colorado, an area of approximately 55,000 km2. Using new and existing geologic maps, the more than 200 rock formations represented in the area were arranged into 17 groups based on lithologic similarity. The dominant regional geologic feature affecting water quality in central Colorado is the Colorado mineral belt (CMB), a NE-trending zone hosting many polymetallic vein or replacement deposits, and porphyry Mo deposits, many of which have been mined historically. The influence of the CMB is seen in lower surface-water pH (<5), and higher concentrations of SO42 - (>100 mg/L) and chalcophile metals such as Cu (>10 ??g/L), Zn (>100 ??g/L), and Cd (>1 ??g/L) relative to surface water outside the CMB. Not all streams within the CMB have been affected by mineralization, as there are numerous catchments within the CMB that have no mineralization or alteration exposed at the surface. At the regional-scale, and away from sites affected by mineralization, hydrothermal alteration, or mining, the effects of lithology on water quality can be distinguished using geochemical reaction modeling and principal components analysis. At local scales (100 s of km2), effects of individual rock units on water chemistry are subtle but discernible, as shown by variations in concentrations of major lithophile elements or ratios between them. These results demonstrate the usefulness of regional geochemical sampling of surface waters and process-based interpretations incorporating geologic and geochemical understanding to establish geochemical baselines.

Opportunity Examines Cracks and Coatings on Mars Rocks

NASA Technical Reports Server (NTRS)

2005-01-01

This false-color panoramic image, taken on martian day, or sol, 561 (Aug. 22, 2005) by NASA's Opportunity rover, shows the nature of the outcrop rocks that the rover is encountering on its southward journey across the martian plains to 'Erebus Crater.' The rocks, similar in make-up to those encountered earlier in the mission, display a clear pattern of cracks as well as rind-like features (identifiable as a light shade of blue to olive in the image) coating the outcrop surface. Prominent in the image are two holes (one on the rock, one on the rind) drilled with the rover's rock abrasion tool to facilitate chemical analysis of the underlying material. The reddish color around the holes is from iron-rich dust produced during the grinding operation. The rind, nicknamed 'Lemon Rind,' and the underlying rock, nicknamed 'Strawberry,' have turned out to be similar in overall chemistry and texture. Science team members are working to understand the nature of the relationship between these kinds of rocks and rinds on the Meridiani plains. This false-color composite was generated from a combination of 750-, 530-, and 430-nanometer filter images taken by the Opportunity panoramic camera, an instrument that has acquired more than 36,000 color filter images to date of martian terrain at Meridiani Planum.

The Potential of Low-Cost Rpas for Multi-View Reconstruction of Sub-Vertical Rock Faces

NASA Astrophysics Data System (ADS)

Thoeni, K.; Guccione, D. E.; Santise, M.; Giacomini, A.; Roncella, R.; Forlani, G.

2016-06-01

The current work investigates the potential of two low-cost off-the-shelf quadcopters for multi-view reconstruction of sub-vertical rock faces. The two platforms used are a DJI Phantom 1 equipped with a Gopro Hero 3+ Black and a DJI Phantom 3 Professional with integrated camera. The study area is a small sub-vertical rock face. Several flights were performed with both cameras set in time-lapse mode. Hence, images were taken automatically but the flights were performed manually as the investigated rock face is very irregular which required manual adjustment of the yaw and roll for optimal coverage. The digital images were processed with commercial SfM software packages. Several processing settings were investigated in order to find out the one providing the most accurate 3D reconstruction of the rock face. To this aim, all 3D models produced with both platforms are compared to a point cloud obtained with a terrestrial laser scanner. Firstly, the difference between the use of coded ground control targets and the use of natural features was studied. Coded targets generally provide the best accuracy, but they need to be placed on the surface, which is not always possible, as sub-vertical rock faces are not easily accessible. Nevertheless, natural features can provide a good alternative if wisely chosen as shown in this work. Secondly, the influence of using fixed interior orientation parameters or self-calibration was investigated. The results show that, in the case of the used sensors and camera networks, self-calibration provides better results. To support such empirical finding, a numerical investigation using a Monte Carlo simulation was performed.

Crustal surface wave velocity structure of the east Albany-Fraser Orogen, Western Australia, from ambient noise recordings

NASA Astrophysics Data System (ADS)

Sippl, C.; Kennett, B. L. N.; Tkalčić, H.; Gessner, K.; Spaggiari, C. V.

2017-09-01

Group and phase velocity maps in the period range 2-20 s for the Proterozoic east Albany-Fraser Orogen, Western Australia, are extracted from ambient seismic noise recorded with the 70-station ALFREX array. This 2 yr temporary installation provided detailed coverage across the orogen and the edge of the Neoarchean Yilgarn Craton, a region where no passive seismic studies of this scale have occurred to date. The surface wave velocities are rather high overall (>3 km s-1 nearly everywhere), as expected for exposed Proterozoic basement rocks. No clear signature of the transition between Yilgarn Craton and Albany-Fraser Orogen is observed, but several strong anomalies corresponding to more local geological features were obtained. A prominent, NE-elongated high-velocity anomaly in the northern part of the array is coincident with a Bouguer gravity high caused by the upper crustal metamorphic rocks of the Fraser Zone. This feature disappears towards longer periods, which hints at an exclusively upper crustal origin for this anomaly. Further east, the limestones of the Cenozoic Eucla Basin are clearly imaged as a pronounced low-velocity zone at short periods, but the prevalence of low velocities to periods of ≥5 s implies that the uppermost basement in this area is likewise slow. At longer periods, slightly above-average surface wave velocities are imaged below the Eucla Basin.

Mineral displacement and -dissolution processes and their relevance to rock porosity and permeability in Rotliegend sandstones of the Altmark natural gas field (central Germany) - results from CO2 laboratory batch experiments

NASA Astrophysics Data System (ADS)

Pudlo, Dieter; Enzmann, Frieder; Heister, Katja; Werner, Lars; Ganzer, Leonhard; Reitenbach, Viktor; Henkel, Steven; Albrecht, Daniel; Gaupp, Reinhard

2014-05-01

The Rotliegend reservoir sandstones of the Altmark area (central Germany) comprise the second largest natural gas field of Europe. These sandstones were deposited on a playa-like continental platform with braided river systems, ephemeral lakes and aeolian dunes under semi-arid conditions. Some of the pristine, red coloured deposits suffered intensive late diagenetic alteration and are now preserved as bleached, high porous and permeable sandstones. To evaluate the relevance of distinct fluids and their fluid-rock alteration reactions on such bleaching processes we performed laboratory static batch experiments on the Altmark sandstones. These 4-6 week lasting runs were conducted with CO2 saturated synthetic brines under typical Altmark reservoir conditions (p= 20 MPa, T= 125°C). Thereby mineralogical, petrophysical and (hydro- and geo-) chemical rock features were maintained prior and after the experiments. Chemical data proved the dissolution of carbonate and sulphate minerals during the runs, whereas the variation in abundance of further elements was within the detection limit of analytical accuracy. However, FE-SEM investigations on used, evaporated brines reveal the presence of illite and chlorite minerals within a matrix of Ca-, Si-, Fe, Al-, Na- and S components (carbonate, anhydrite, albite and Fe-(hydr-) oxides ?). By porosity and relative permeability measurements an increase in both rock features was observed after the runs, indicating that mineral dissolution and/or (clay) fine migration/detachment occurred during the experiments. Mineral dissolution, especially of pore-filling cements (e.g. carbonate-, sulphate minerals) is also deduced by BET analysis, in determining the specific surface of the sandstones. The size of these reactive surfaces increased after the experiments, suggesting that after the dissolution of pore-filling cements, formerly armoured grain rimming clay cutans were exposed to potential migrating fluids. These findings are also supported by µ-CT investigations. Here, the achieved 3D modelling data indicate an increase in reactive surface areas exposed to the pore space (which is in accord to the BET observations), as well as an enhancement in rock porosity and permeability after the runs. Moreover, these simulations showed that a remarkable mass (mineral) transfer was induced by the experiments, which led to a displacement of the porosity and permeability distribution in the sandstones and therefore a change in the fluid flow characteristics within the rocks - a parameter most important for every fluid-rock process. These observations are quite astonishing because they suggest that not only fluid velocity (e.g. during fluid flow experiments) might detach and transport grain rimming (clay) minerals, but also that physico-chemical reactions may enforce the release of such solids, even during almost static p-/T-/Xfluid conditions, as used in our experiments.

Crack propagation and coalescence due to dual non-penetrating surface flaws and their effect on the strength of rock-like material

NASA Astrophysics Data System (ADS)

Xu, Jun; Zheng, Zheyuan; Xiao, Xiaochun; Li, Zhaoxia

2018-06-01

Non-penetrating surface flaws play a key role in the fracture process of rock-like material, and could cause localized collapse and even failure of the materials. Until now, the mechanism and the effect of surface crack propagation have remained unclear. In this paper, compression tests on gypsum (a soft rock material) are conducted to investigate crack propagation and coalescence due to non-penetrating surface flaws and their effect on the material strength. Specimens are tested under dual pre-existing surface flaws with various combinations of depth and spacing. The results show that when the pre-existing flaws are non-penetrating, the d/t ratio (flaw depth ratio, d is the pre-existing flaw cutting depth and t is the specimen thickness) and the spacing (the distance between the two flaw internal tips) have a strong influence on surface crack patterns and specimen strength. Few cracks emanate from the pre-existing flaws when the flaw depth ratio is equal to 1/3, and more cracks occur with the increase of the flaw depth ratio. When the pre-existing flaw penetrates completely through the specimen, the spacing has a small effect on the specimen strength. A larger flaw depth ratio could advance the occurrence of the peak load (PL) and result in a smaller specimen residual strength. The failure process of the specimen is divided into several stages featured by a stepped decline of the load value after PL, which is closely related to the initiation and propagation of secondary cracks. In addition, the spalling (failure of a portion of the surface caused by coalescence of cracks) can be regarded as indicating the failure of the specimen, and two possible types of spalling formation are briefly discussed.

Xenoliths in maars and diatremes with inferences for the moon, Mars, and Venus.

NASA Technical Reports Server (NTRS)

Mcgetchin, T. R.; Ullrich, G. W.

1973-01-01

Some field observations of the occurrence of deep-seated rock fragments in three terrestrial volcanic features that may have counterparts on the moon or Mars are reviewed, and results of numerical hydrodynamic calculations of the eruption of these types of volcanoes are presented. In particular, the transport of entrained fragmental debris is investigated for the surface (muzzle) velocity of fragments that it yields as a function of fragment size and various values of surface gravity. The implications of these observations and inferences for possible future space missions are examined.

In-Situ and Experimental Evidence for Acidic Weathering of Rocks and Soils on Mars

NASA Technical Reports Server (NTRS)

Hurowitz, J. A.; McLennan, S. M.; Tosca, N. J.; Arvidson, R. E.; Michalski, J. R.; Ming, D.; Schroeder, C.; Squyres, S. W.

2006-01-01

Experimental data for alteration of synthetic Martian basalts at pH=0-1 indicate that chemical fractionations at low pH are vastly different from those observed during terrestrial weathering. Rock analyses from Gusev crater are well described by the relationships apparent from low pH experimental alteration data. A model for rock surface alteration is developed which indicates that a leached alteration zone is present on rock surfaces at Gusev. This zone is not chemically fractionated to a large degree from the underlying rock interior, indicating that the rock surface alteration process has occurred at low fluid-to-rock ratio. The geochemistry of natural rock surfaces analyzed by APXS is consistent with a mixture between adhering soil/dust and the leached alteration zone. The chemistry of rock surfaces analyzed after brushing with the RAT is largely representative of the leached alteration zone. The chemistry of rock surfaces analyzed after grinding with the RAT is largely representative of the interior of the rock, relatively unaffected by the alteration process occurring at the rock surface. Elemental measurements from the Spirit, Opportunity, Pathfinder and Viking 1 landing sites indicate that soil chemistry from widely separated locations is consistent with the low-pH, low fluid to rock ratio alteration relationships developed for Gusev rocks. Soils are affected principally by mobility of FeO and MgO, consistent with alteration of olivine-bearing basalt and subsequent precipitation of FeO and MgO bearing secondary minerals as the primary control on soil geochemistry.

Response comment: Carbon sequestration on Mars

USGS Publications Warehouse

Edwards, Christopher; Ehlmann, Bethany L.

2016-01-01

Martian atmospheric pressure has important implications for the past and present habitability of the planet, including the timing and causes of environmental change. The ancient Martian surface is strewn with evidence for early water bound in minerals (e.g., Ehlmann and Edwards, 2014) and recorded in surface features such as large catastrophically created outflow channels (e.g., Carr, 1979), valley networks (Hynek et al., 2010; Irwin et al., 2005), and crater lakes (e.g., Fassett and Head, 2008). Using orbital spectral data sets coupled with geologic maps and a set of numerical spectral analysis models, Edwards and Ehlmann (2015) constrained the amount of atmospheric sequestration in early Martian rocks and found that the majority of this sequestration occurred prior to the formation of the early Hesperian/late Noachian valley networks (Fassett and Head, 2011; Hynek et al., 2010), thus implying the atmosphere was already thin by the time these surface-water-related features were formed.

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

NASA Astrophysics Data System (ADS)

Mustard, J. F.; Pascuzzo, A.

2017-12-01

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

30 CFR 717.15 - Disposal of excess rock and earth materials on surface areas.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Disposal of excess rock and earth materials on surface areas. 717.15 Section 717.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS § 717.15 Disposal of excess rock and earth materials on surface areas. Excess rock and earth...

30 CFR 717.15 - Disposal of excess rock and earth materials on surface areas.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Disposal of excess rock and earth materials on surface areas. 717.15 Section 717.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS § 717.15 Disposal of excess rock and earth materials on surface areas. Excess rock and earth...

30 CFR 717.15 - Disposal of excess rock and earth materials on surface areas.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Disposal of excess rock and earth materials on surface areas. 717.15 Section 717.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS § 717.15 Disposal of excess rock and earth materials on surface areas. Excess rock and earth...

30 CFR 717.15 - Disposal of excess rock and earth materials on surface areas.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Disposal of excess rock and earth materials on surface areas. 717.15 Section 717.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS § 717.15 Disposal of excess rock and earth materials on surface areas. Excess rock and earth...

Absolute stress measurements at the rangely anticline, Northwestern Colorado

USGS Publications Warehouse

de la Cruz, R. V.; Raleigh, C.B.

1972-01-01

Five different methods of measuring absolute state of stress in rocks in situ were used at sites near Rangely, Colorado, and the results compared. For near-surface measurements, overcoring of the borehole-deformation gage is the most convenient and rapid means of obtaining reliable values for the magnitude and direction of the state of stress in rocks in situ. The magnitudes and directions of the principal stresses are compared to the geologic features of the different areas of measurement. The in situ stresses are consistent in orientation with the stress direction inferred from the earthquake focal-plane solutions and existing joint patterns but inconsistent with stress directions likely to have produced the Rangely anticline. ?? 1972.

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

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

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

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

Analysis of terrestrial and Martian volcanic compositions using thermal emission spectroscopy

NASA Astrophysics Data System (ADS)

Wyatt, Michael Bruce

2002-11-01

This dissertation comprises four separate parts that address the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) investigation objective of determining and mapping the composition and distribution of surface minerals and rocks on Mars from orbit. In Part 1, laboratory thermal infrared spectra (5 25 μm, at 2 cm-1 spectral sampling), deconvolved modal mineralogies, and derived mineral and bulk rock chemistries of basalt, basaltic andesite, andesite, and dacite were used to evaluate and revise volcanic rock classification schemes. Multiple steps of classification were required to distinguish volcanic rocks, reflecting the mineralogic diversity and continuum of compositions that exists in volcanic rock types. In Part 2, laboratory spectral data were convolved to TES 10 cm-1 sampling to ascertain whether adequate results for volcanic rock classification can be obtained with lower spectral resolution, comparable to that obtained from Mars orbit. Modeled spectra, modeled modal mineralogies, and derived bulk rock chemistries at low (10 cm-1) spectral sampling provide good matches to measured and high (2 cm-1) spectral sampling modeled values. These results demonstrate the feasibility of using similar techniques and classification schemes for the interpretation of terrestrial laboratory samples and TES-resolution data. In Part 3, new deconvolved mineral abundances from TES data and terrestrial basalts using a spectral end-member set representing minerals common in unaltered and low-temperature aqueously altered basalts were used to reclassify martian surface lithologies. The new formulations maintain the dominance of unaltered basalt in the southern highlands, but indicate the northern lowlands can be interpreted as weathered basalt. The coincidence between locations of altered basalt and a previously suggested northern ocean basin implies that lowland plains materials may be basalts altered under submarine conditions and/or weathered basaltic sediment transported into this depocenter. In Part 4, results from the previous parts are applied to examine the distribution of TES-derived surface compositions in the Oxia Palus region on Mars through high-spatial resolution mapping. Features of interest within Oxia Palus include volcanic/sedimentary materials in southern Acidalia Planitia, low-albedo crater floors and wind streaks in western Arabia Terra, and channel outflow deposits of the Mars Pathfinder (MP) landing site.

Martian soil stratigraphy and rock coatings observed in color-enhanced Viking Lander images

NASA Technical Reports Server (NTRS)

Strickland, E. L., III

1979-01-01

Subtle color variations of martian surface materials were enhanced in eight Viking Lander (VL) color images. Well-defined soil units recognized at each site (six at VL-1 and four at VL-2), are identified on the basis of color, texture, morphology, and contact relations. The soil units at the Viking 2 site form a well-defined stratigraphic sequence, whereas the sequence at the Viking 1 site is only partially defined. The same relative soil colors occur at the two sites, suggesting that similar soil units are widespread on Mars. Several types of rock surface materials can be recognized at the two sites; dark, relatively 'blue' rock surfaces are probably minimally weathered igneous rock, whereas bright rock surfaces, with a green/(blue + red) ratio higher than that of any other surface material, are interpreted as a weathering product formed in situ on the rock. These rock surface types are common at both sites. Soil adhering to rocks is common at VL-2, but rare at VL-1. The mechanism that produces the weathering coating on rocks probably operates planet-wide.

Overview of the Opportunity Mars Exploration Rover Mission to Meridiani Planum: Eagle Crater to Purgatory Ripple

NASA Astrophysics Data System (ADS)

Squyres, S. W.; Arvidson, R. E.; Bollen, D.; Bell, J. F.; Brückner, J.; Cabrol, N. A.; Calvin, W. M.; Carr, M. H.; Christensen, P. R.; Clark, B. C.; Crumpler, L.; Des Marais, D. J.; d'Uston, C.; Economou, T.; Farmer, J.; Farrand, W. H.; Folkner, W.; Gellert, R.; Glotch, T. D.; Golombek, M.; Gorevan, S.; Grant, J. A.; Greeley, R.; Grotzinger, J.; Herkenhoff, K. E.; Hviid, S.; Johnson, J. R.; Klingelhöfer, G.; Knoll, A. H.; Landis, G.; Lemmon, M.; Li, R.; Madsen, M. B.; Malin, M. C.; McLennan, S. M.; McSween, H. Y.; Ming, D. W.; Moersch, J.; Morris, R. V.; Parker, T.; Rice, J. W.; Richter, L.; Rieder, R.; Schröder, C.; Sims, M.; Smith, M.; Smith, P.; Soderblom, L. A.; Sullivan, R.; Tosca, N. J.; Wänke, H.; Wdowiak, T.; Wolff, M.; Yen, A.

2006-12-01

The Mars Exploration Rover Opportunity touched down at Meridiani Planum in January 2004 and since then has been conducting observations with the Athena science payload. The rover has traversed more than 5 km, carrying out the first outcrop-scale investigation of sedimentary rocks on Mars. The rocks of Meridiani Planum are sandstones formed by eolian and aqueous reworking of sand grains that are composed of mixed fine-grained siliciclastics and sulfates. The siliciclastic fraction was produced by chemical alteration of a precursor basalt. The sulfates are dominantly Mg-sulfates and also include Ca-sulfates and jarosite. The stratigraphic section observed to date is dominated by eolian bedforms, with subaqueous current ripples exposed near the top of the section. After deposition, interaction with groundwater produced a range of diagenetic features, notably the hematite-rich concretions known as ``blueberries.'' The bedrock at Meridiani is highly friable and has undergone substantial erosion by wind-transported basaltic sand. This sand, along with concretions and concretion fragments eroded from the rock, makes up a soil cover that thinly and discontinuously buries the bedrock. The soil surface exhibits both ancient and active wind ripples that record past and present wind directions. Loose rocks on the soil surface are rare and include both impact ejecta and meteorites. While Opportunity's results show that liquid water was once present at Meridiani Planum below and occasionally at the surface, the environmental conditions recorded were dominantly arid, acidic, and oxidizing and would have posed some significant challenges to the origin of life.

A diffuse radar scattering model from Martian surface rocks

NASA Technical Reports Server (NTRS)

Calvin, W. M.; Jakosky, B. M.; Christensen, P. R.

1987-01-01

Remote sensing of Mars has been done with a variety of instrumentation at various wavelengths. Many of these data sets can be reconciled with a surface model of bonded fines (or duricrust) which varies widely across the surface and a surface rock distribution which varies less so. A surface rock distribution map from -60 to +60 deg latitude has been generated by Christensen. Our objective is to model the diffuse component of radar reflection based on this surface distribution of rocks. The diffuse, rather than specular, scattering is modeled because the diffuse component arises due to scattering from rocks with sizes on the order of the wavelength of the radar beam. Scattering for radio waves of 12.5 cm is then indicative of the meter scale and smaller structure of the surface. The specular term is indicative of large scale surface undulations and should not be causally related to other surface physical properties. A simplified model of diffuse scattering is described along with two rock distribution models. The results of applying the models to a planet of uniform fractional rock coverage with values ranging from 5 to 20% are discussed.

Evidence for mechanical and chemical alteration of iron-nickel meteorites on Mars: Process insights for Meridiani Planum

USGS Publications Warehouse

Ashley, James W.; Golombek, M.P.; Christensen, P.R.; Squyres, S. W.; McCoy, T.J.; Schroder, C.; Fleischer, I.; Johnson, J. R.; Herkenhoff, K. E.; Parker, T.J.

2011-01-01

The weathering of meteorites found on Mars involves chemical and physical processes that can provide clues to climate conditions at the location of their discovery. Beginning on sol 1961, the Opportunity rover encountered three large iron meteorites within a few hundred meters of each other. In order of discovery, these rocks have been assigned the unofficial names Block Island, Shelter Island, and Mackinac Island. Each rock presents a unique but complimentary set of features that increase our understanding of weathering processes at Meridiani Planum. Significant morphologic characteristics interpretable as weathering features include (1) a large pit in Block Island, lined with delicate iron protrusions suggestive of inclusion removal by corrosive interaction; (2) differentially eroded kamacite and taenite lamellae in Block Island and Shelter Island, providing relative timing through crosscutting relationships with deposition of (3) an iron oxide-rich dark coating; (4) regmaglypted surfaces testifying to regions of minimal surface modification, with other regions in the same meteorites exhibiting (5) large-scale, cavernous weathering (in Shelter Island and Mackinac Island). We conclude that the current size of the rocks is approximate to their original postfall contours. Their morphology thus likely results from a combination of atmospheric interaction and postfall weathering effects. Among our specific findings is evidence supporting (1) at least one possible episode of aqueous acidic exposure for Block Island; (2) ripple migration over portions of the meteorites; (3) a minimum of two separate episodes of wind abrasion; alternating with (4) at least one episode of coating-forming chemical alteration, most likely at subzero temperatures. Copyright 2011 by the American Geophysical Union.

Arsia Mons by Day and Night

NASA Image and Video Library

2004-06-22

Released 22 June 2004 This pair of images shows part of Arsia Mons. Day/Night Infrared Pairs The image pairs presented focus on a single surface feature as seen in both the daytime and nighttime by the infrared THEMIS camera. The nighttime image (right) has been rotated 180 degrees to place north at the top. Infrared image interpretation Daytime: Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark. Nighttime: Infrared images taken during the nighttime exhibit only the thermophysical properties of the surface of Mars. The effect of sun-facing versus non-sun-facing energy dissipates quickly at night. Thermophysical effects dominate as different surfaces cool at different rates through the nighttime hours. Rocks cool slowly, and are therefore relatively bright at night (remember that rocks are dark during the day). Dust and other fine grained materials cool very quickly and are dark in nighttime infrared images. Image information: IR instrument. Latitude -19.6, Longitude 241.9 East (118.1 West). 100 meter/pixel resolution. http://photojournal.jpl.nasa.gov/catalog/PIA06399

Crater Ejecta by Day and Night

NASA Image and Video Library

2004-06-24

Released 24 June 2004 This pair of images shows a crater and its ejecta. Day/Night Infrared Pairs The image pairs presented focus on a single surface feature as seen in both the daytime and nighttime by the infrared THEMIS camera. The nighttime image (right) has been rotated 180 degrees to place north at the top. Infrared image interpretation Daytime: Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark. Nighttime: Infrared images taken during the nighttime exhibit only the thermophysical properties of the surface of Mars. The effect of sun-facing versus non-sun-facing energy dissipates quickly at night. Thermophysical effects dominate as different surfaces cool at different rates through the nighttime hours. Rocks cool slowly, and are therefore relatively bright at night (remember that rocks are dark during the day). Dust and other fine grained materials cool very quickly and are dark in nighttime infrared images. Image information: IR instrument. Latitude -9, Longitude 164.2 East (195.8 West). 100 meter/pixel resolution. http://photojournal.jpl.nasa.gov/catalog/PIA06445

Automated extraction and analysis of rock discontinuity characteristics from 3D point clouds

NASA Astrophysics Data System (ADS)

Bianchetti, Matteo; Villa, Alberto; Agliardi, Federico; Crosta, Giovanni B.

2016-04-01

A reliable characterization of fractured rock masses requires an exhaustive geometrical description of discontinuities, including orientation, spacing, and size. These are required to describe discontinuum rock mass structure, perform Discrete Fracture Network and DEM modelling, or provide input for rock mass classification or equivalent continuum estimate of rock mass properties. Although several advanced methodologies have been developed in the last decades, a complete characterization of discontinuity geometry in practice is still challenging, due to scale-dependent variability of fracture patterns and difficult accessibility to large outcrops. Recent advances in remote survey techniques, such as terrestrial laser scanning and digital photogrammetry, allow a fast and accurate acquisition of dense 3D point clouds, which promoted the development of several semi-automatic approaches to extract discontinuity features. Nevertheless, these often need user supervision on algorithm parameters which can be difficult to assess. To overcome this problem, we developed an original Matlab tool, allowing fast, fully automatic extraction and analysis of discontinuity features with no requirements on point cloud accuracy, density and homogeneity. The tool consists of a set of algorithms which: (i) process raw 3D point clouds, (ii) automatically characterize discontinuity sets, (iii) identify individual discontinuity surfaces, and (iv) analyse their spacing and persistence. The tool operates in either a supervised or unsupervised mode, starting from an automatic preliminary exploration data analysis. The identification and geometrical characterization of discontinuity features is divided in steps. First, coplanar surfaces are identified in the whole point cloud using K-Nearest Neighbor and Principal Component Analysis algorithms optimized on point cloud accuracy and specified typical facet size. Then, discontinuity set orientation is calculated using Kernel Density Estimation and principal vector similarity criteria. Poles to points are assigned to individual discontinuity objects using easy custom vector clustering and Jaccard distance approaches, and each object is segmented into planar clusters using an improved version of the DBSCAN algorithm. Modal set orientations are then recomputed by cluster-based orientation statistics to avoid the effects of biases related to cluster size and density heterogeneity of the point cloud. Finally, spacing values are measured between individual discontinuity clusters along scanlines parallel to modal pole vectors, whereas individual feature size (persistence) is measured using 3D convex hull bounding boxes. Spacing and size are provided both as raw population data and as summary statistics. The tool is optimized for parallel computing on 64bit systems, and a Graphic User Interface (GUI) has been developed to manage data processing, provide several outputs, including reclassified point clouds, tables, plots, derived fracture intensity parameters, and export to modelling software tools. We present test applications performed both on synthetic 3D data (simple 3D solids) and real case studies, validating the results with existing geomechanical datasets.

Three-dimensional geologic map of the Hayward fault, northern California: Correlation of rock unites with variations in seismicity, creep rate, and fault dip

USGS Publications Warehouse

Graymer, R.W.; Ponce, D.A.; Jachens, R.C.; Simpson, R.W.; Phelps, G.A.; Wentworth, C.M.

2005-01-01

In order to better understand mechanisms of active faults, we studied relationships between fault behavior and rock units along the Hayward fault using a three-dimensional geologic map. The three-dimensional map-constructed from hypocenters, potential field data, and surface map data-provided a geologic map of each fault surface, showing rock units on either side of the fault truncated by the fault. The two fault-surface maps were superimposed to create a rock-rock juxtaposition map. The three maps were compared with seismicity, including aseismic patches, surface creep, and fault dip along the fault, by using visuallization software to explore three-dimensional relationships. Fault behavior appears to be correlated to the fault-surface maps, but not to the rock-rock juxtaposition map, suggesting that properties of individual wall-rock units, including rock strength, play an important role in fault behavior. Although preliminary, these results suggest that any attempt to understand the detailed distribution of earthquakes or creep along a fault should include consideration of the rock types that abut the fault surface, including the incorporation of observations of physical properties of the rock bodies that intersect the fault at depth. ?? 2005 Geological Society of America.

Dust storms on Mars: Considerations and simulations

NASA Technical Reports Server (NTRS)

Greeley, R.; White, B. R.; Pollack, J. B.; Iverson, J. D.; Leach, R. N.

1977-01-01

Aeolian processes are important in modifying the surface of Mars at present, and appear to have been significant in the geological past. Aeolian activity includes local and global dust storms, the formation of erosional features such as yardangs and depositional features such as sand dunes, and the erosion of rock and soil. As a means of understanding aeolian processes on Mars, an investigation is in progress that includes laboratory simulations, field studies of earth analogs, and interpretation of spacecraft data. This report describes the Martian Surface Wind Tunnel, an experimental facility established at NASA-Ames Research Center, and presents some results of the general investigation. Experiments dealing with wind speeds and other conditions required for the initiation of particle movement on Mars are described and considerations are given to the resulting effectiveness of aeolian erosion.

Remote Sensing of Martian Terrain Hazards via Visually Salient Feature Detection

NASA Astrophysics Data System (ADS)

Al-Milli, S.; Shaukat, A.; Spiteri, C.; Gao, Y.

2014-04-01

The main objective of the FASTER remote sensing system is the detection of rocks on planetary surfaces by employing models that can efficiently characterise rocks in terms of semantic descriptions. The proposed technique abates some of the algorithmic limitations of existing methods with no training requirements, lower computational complexity and greater robustness towards visual tracking applications over long-distance planetary terrains. Visual saliency models inspired from biological systems help to identify important regions (such as rocks) in the visual scene. Surface rocks are therefore completely described in terms of their local or global conspicuity pop-out characteristics. These local and global pop-out cues are (but not limited to); colour, depth, orientation, curvature, size, luminance intensity, shape, topology etc. The currently applied methods follow a purely bottom-up strategy of visual attention for selection of conspicuous regions in the visual scene without any topdown control. Furthermore the choice of models used (tested and evaluated) are relatively fast among the state-of-the-art and have very low computational load. Quantitative evaluation of these state-ofthe- art models was carried out using benchmark datasets including the Surrey Space Centre Lab Testbed, Pangu generated images, RAL Space SEEKER and CNES Mars Yard datasets. The analysis indicates that models based on visually salient information in the frequency domain (SRA, SDSR, PQFT) are the best performing ones for detecting rocks in an extra-terrestrial setting. In particular the SRA model seems to be the most optimum of the lot especially that it requires the least computational time while keeping errors competitively low. The salient objects extracted using these models can then be merged with the Digital Elevation Models (DEMs) generated from the same navigation cameras in order to be fused to the navigation map thus giving a clear indication of the rock locations.

Dual-Spectroscopy Platform for the Surveillance of Mars Mineralogy Using a Decisions Fusion Architecture on Simultaneous LIBS-Raman Data.

PubMed

Moros, Javier; ElFaham, Mohamed Mostafa; Laserna, J Javier

2018-02-06

A single platform, integrated by a laser-induced breakdown spectroscopy detector and a Raman spectroscopy sensor, has been designed to remotely (5 m) and simultaneously register the elemental and molecular signatures of rocks under Martian surface conditions. From this information, new data fusion architecture at decisions level is proposed for the correct categorization of the rocks. The approach is based on a decision-making process from the sequential checking of the spectral features representing the cationic and anionic counterparts of the specimen. The scrutiny of the LIBS response by using a moving-window algorithm informs on the diversity of the elemental constituents. The output rate of emission lines allows projecting in a loop the elements as the cationic counterpart of the rock. In parallel, the Raman response of the unknown is compared with all the molecular counterparts of the hypothesized cation that are stored in a spectral library. The largest similarity rate unveils the final identity of the unknown. The identification capabilities of the architecture have been underscored through blind tests of 10 natural rocks with different origins. The great majority of forecasts have matched with the real identities of the inspected targets. The strength of this platform to simultaneously acquire the multielemental and the molecular information from a specimen by using the same laser events greatly enhances the "on-surface" missions for the surveillance of mineralogy.

Distribution of hydrothermally altered rocks in the Reko Diq, Pakistan mineralized area based on spectral analysis of ASTER data

USGS Publications Warehouse

Rowan, L.C.; Schmidt, R.G.; Mars, J.C.

2006-01-01

The Reko Diq, Pakistan mineralized study area, approximately 10??km in diameter, is underlain by a central zone of hydrothermally altered rocks associated with Cu-Au mineralization. The surrounding country rocks are a variable mixture of unaltered volcanic rocks, fluvial deposits, and eolian quartz sand. Analysis of 15-band Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data of the study area, aided by laboratory spectral reflectance and spectral emittance measurements of field samples, shows that phyllically altered rocks are laterally extensive, and contain localized areas of argillically altered rocks. In the visible through shortwave-infrared (VNIR + SWIR) phyllically altered rocks are characterized by Al-OH absorption in ASTER band 6 because of molecular vibrations in muscovite, whereas argillically altered rocks have an absorption feature in band 5 resulting from alunite. Propylitically altered rocks form a peripheral zone and are present in scattered exposures within the main altered area. Chlorite and muscovite cause distinctive absorption features at 2.33 and 2.20????m, respectively, although less intense 2.33????m absorption is also present in image spectra of country rocks. Important complementary lithologic information was derived by analysis of the spectral emittance data in the 5 thermal-infrared (TIR) bands. Silicified rocks were not distinguished in the 9 VNIR + SWIR bands because of the lack of diagnostic spectral absorption features in quartz in this wavelength region. Quartz-bearing surficial deposits, as well as hydrothermally silicified rocks, were mapped in the TIR bands by using a band 13/band 12 ratio image, which is sensitive to the intensity of the quartz reststrahlen feature. Improved distinction between the quartzose surficial deposits and silicified bedrock was achieved by using matched-filter processing with TIR image spectra for reference. ?? 2006 Elsevier Inc. All rights reserved.

Spatial database of mining-related features in 2001 at selected phosphate mines, Bannock, Bear Lake, Bingham, and Caribou Counties, Idaho

USGS Publications Warehouse

Moyle, Phillip R.; Kayser, Helen Z.

2006-01-01

This report describes the spatial database, PHOSMINE01, and the processes used to delineate mining-related features (active and inactive/historical) in the core of the southeastern Idaho phosphate resource area. The spatial data have varying degrees of accuracy and attribution detail. Classification of areas by type of mining-related activity at active mines is generally detailed; however, for many of the closed or inactive mines the spatial coverage does not differentiate mining-related surface disturbance features. Nineteen phosphate mine sites are included in the study, three active phosphate mines - Enoch Valley (nearing closure), Rasmussen Ridge, and Smoky Canyon - and 16 inactive (or historical) phosphate mines - Ballard, Champ, Conda, Diamond Gulch, Dry Valley, Gay, Georgetown Canyon, Henry, Home Canyon, Lanes Creek, Maybe Canyon, Mountain Fuel, Trail Canyon, Rattlesnake, Waterloo, and Wooley Valley. Approximately 6,000 hc (15,000 ac), or 60 km2 (23 mi2) of phosphate mining-related surface disturbance are documented in the spatial coverage. Spatial data for the inactive mines is current because no major changes have occurred; however, the spatial data for active mines were derived from digital maps prepared in early 2001 and therefore recent activity is not included. The inactive Gay Mine has the largest total area of disturbance, 1,900 hc (4,700 ac) or about 19 km2 (7.4 mi2). It encompasses over three times the disturbance area of the next largest mine, the Conda Mine with 610 hc (1,500 ac), and it is nearly four times the area of the Smoky Canyon Mine, the largest of the active mines with about 550 hc (1,400 ac). The wide range of phosphate mining-related surface disturbance features (141) from various industry maps were reduced to 15 types or features based on a generic classification system used for this study: mine pit; backfilled mine pit; waste rock dump; adit and waste rock dump; ore stockpile; topsoil stockpile; tailings or tailings pond; sediment catchment; facilities; road; railroad; water reservoir; disturbed land, undifferentiated; and undisturbed land. In summary, the spatial coverage includes polygons totaling about 1,100 hc (2,800 ac) of mine pits, 440 hc (1100 ac) of backfilled mine pits, 1,600 hc (3,800 ac) of waste rock dumps, 31 hc (75 ac) of ore stockpiles, and 44 hc (110 ac) of tailings or tailings ponds. Areas of undifferentiated phosphate mining-related land disturbances, called 'disturbed land, undifferentiated,' total about 2,200 hc (5,500 ac) or nearly 22 km2 (8.6 mi2). No determination has been made as to status of reclamation on any of the lands. Subsequent site-specific studies to delineate distinct mine features will allow additional revisions to this spatial database.

Geological and geographical investigations of an Apollo 9 photo anomaly near Point of Pines, Arizona

USGS Publications Warehouse

Bromfield, Calvin S.; Eaton, G.P.; Peterson, D.L.; Ratte, J.C.

1972-01-01

An infrared photograph of southeastern Arizona, taken during the Apollo 9 multispectral terrain photography experiment in 1969, reveals a ringlike feature, some 3-4 miles (5-6 kin) in diameter, on the Natanes Plateau, 35 miles (56 kin) north of the town of Safford. Because the feature occurs in an area of nearly flat lying Tertiary volcanic rocks, the possibilities of its being a small collapse caldera or an exposed circular intrusive body were considered. Geological and geophysical studies of the area were made to test these hypotheses. The local stratigraphic section consists of approximately 1,500 feet (457 m) of Oligocene and perhaps older volcanic rocks, resting on a moderately irregular basement surface carved from nearly flat lying trending Basin-and-Range faults define a broad horst within which two arcuate cross faults, with 300-600 feet (91-183 m) of displacement, bound a downdropped area. Deep erosion along these faults has created a polygonal network of canyons which constitutes the 'ring' seen on the photograph. A mild arching of the volcanic rocks within the ring is suggested by structure contours on the base of the youngest flows. A sharp 350-gamma positive aeromagnetic anomaly is centered within the ring. In its southwest quadrant the anomaly has an elongate extension that trends northwest along an adjoining Basin-and-Range fault. Associated with both is a subtle gravity low. The geophysical data thus suggest the presence of a small blind silicic pluton, possibly of middle Tertiary or younger age. Although it can be argued that the arcuate faults and mild arching of the volcanic pile are related to this postulated pluton, no evidence of hydrothermal alteration or thermal metamorphism of the country rocks was seen. Thus if a pluton is present and of postvolcanic age, it must have been emplaced as a relatively cool dry body; or alternatively, it is older than the surface volcanic rocks. In either instance, its magnetic expression contrasts with that of the known mineralized Laramide porphyry intrusive bodies of the region.

Geochemistry, mineralogy, and petrology of boninitic and komatiitic rocks on the mercurian surface: Insights into the mercurian mantle

NASA Astrophysics Data System (ADS)

Vander Kaaden, Kathleen E.; McCubbin, Francis M.; Nittler, Larry R.; Peplowski, Patrick N.; Weider, Shoshana Z.; Frank, Elizabeth A.; McCoy, Timothy J.

2017-03-01

Orbital data from the MESSENGER mission to Mercury have facilitated a new view of the planet's structure, chemical makeup, and diverse surface, and have confirmed Mercury's status as a geochemical endmember among the terrestrial planets. In this work, the most recent results from MESSENGER's X-Ray Spectrometer, Gamma-Ray Spectrometer, and Neutron Spectrometer have been used to identify nine distinct geochemical regions on Mercury. Using a variation on the classical CIPW normative mineralogy calculation, elemental composition data is used to constrain the potential mineralogy of Mercury's surface; the calculated silicate mineralogy is dominated by plagioclase, pyroxene (both orthopyroxene and clinopyroxene), and olivine, with lesser amounts of quartz. The range in surface compositions indicate that the rocks on the surface of Mercury are diverse and vary from komatiitic to boninitic. The high abundance of alkalis on Mercury's surface results in several of the nine regions being classified as alkali-rich komatiites and/or boninites. In addition, Mercury's surface terranes span a wide range of SiO2 values that encompass crustal compositions that are more silica-rich than geochemical terranes on the Moon, Mars, and Vesta, but the range is similar to that of Earth. Although the composition of Mercury's surface appears to be chemically evolved, the high SiO2 content is a primitive feature and a direct result of the planet's low oxygen fugacity.

ON-SITE CAVITY LOCATION-SEISMIC PROFILING AT NEVADA TEST SITE

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

Forbes, C.B.; Peterson, R.A.; Heald, C.L.

1961-10-25

Experimental seismic studies were conducted at the Nevada Test Site for the purpose of designing and evaluating the most promising seismic techniques for on-site inspection. Post-explosion seismic profiling was done in volcanic tuff in the vicinity of the Rainier and Blanca underground explosions. Pre-explosion seismic profiling was done over granitic rock outcrops in the Climax Stock area, and over tuff at proposed location for Linen and Orchid. Near surface velocity profiling techniques based on measurements of seismic time-distance curves gave evidence of disturbances in near surface rock velocities over the Rainier and Refer als0 to abstract 30187. Blanca sites. Thesemore » disturbances appear to be related to near surface fracturing and spallation effects resulting from the reflection of the original intense compression wave pulse at the near surface as a tension pulse. Large tuned seismometer arrays were used for horizontal seismic ranging in an attempt to record back-scattered'' or reflected seismic waves from subsurface cavities or zones of rock fracturing around the underground explosions. Some possible seismic events were recorded from the near vicinities of the Rainier and Blanca sites. However, many more similar events were recorded from numerous other locations, presumably originating from naturally occurring underground geological features. No means was found for discriminating between artificial and natural events recorded by horizontal seismic ranging, and the results were, therefore, not immediately useful for inspection purposes. It is concluded that in some instances near surface velocity profiling methods may provide a useful tool in verifying the presence of spalled zones above underground nuclear explosion sites. In the case of horizontal seismic ranging it appears that successful application would require development of satisfactory means for recognition of and discrimination against seismic responses to naturally occurring geological features. It is further concluded that, although more sophisticated instrumentation systems can be conceived, the most promising returns for effort expended can be expected to come from increased experience, skill, and human ingenuity in applying existing techniques. The basic problem is in large part a geological one of differentiating seismic response to man made irregularities from that of natural features which are of a similar or greater size and universally proved. It would not appear realistic to consider the seismic tool as a proven routine device for giving clear answers in on-site inspection operations. Application must still be considered largely experimental. (auth)« less

The Piedmont landscape of Maryland: a new look at an old problem.

USGS Publications Warehouse

Costa, J.E.; Cleaves, E.T.

1984-01-01

Both equilibrium and episodic erosion features can be recognized in the modern landscape. An equilibrium condition is suggested by adjustment of first and second order streams to rock structure and lithology, entrenchment of some streams against gneiss domes, altitudinal zonation of rock types around gneiss domes, correlation of lithology with overburden thickness on uplands, etc. The long-term episodic character of erosion is suggested by clastic wedges on the adjacent Coastal Plain, an upland of low relief that truncates non-carbonate rocks of different lithologies, isovolumetric chemical weathering of alumino-silicate rocks, clastic deposition in marble valleys, and weathering profile truncation by modern drainage. The upland surface preserved in the eastern Piedmont developed by the Late Cretaceous. In the interval from the Late Cretaceous to the Late Miocene, low input of terrigenous sediments to the Coastal Plain, dominance of marine sedimentation, and spotty evidence of saprolite formation on crystalline rocks, suggest that the Maryland Piedmont was an area of low relief undergoing intense weathering. Incised valleys were formed during a cycle of erosion probably initiated in the Late Miocene and extensive colluvial sediments were deposited on hillslopes by periglacial processes during the Pleistocene.-after Authors

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

NASA Astrophysics Data System (ADS)

Raziperchikolaee, Samin

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

Evaluation of magma mixing in the subvolcanic rocks of Ghansura Felsic Dome of Chotanagpur Granite Gneiss Complex, eastern India

NASA Astrophysics Data System (ADS)

Gogoi, Bibhuti; Saikia, Ashima; Ahmad, Mansoor; Ahmad, Talat

2018-06-01

The subvolcanic rocks exposed in the Ghansura Felsic Dome (GFD) of the Bathani volcano-sedimentary sequence at the northern fringe of the Rajgir fold belt in the Proterozoic Chotanagpur Granite Gneiss Complex preserves evidence of magma mixing and mingling in mafic (dolerite), felsic (microgranite) and intermediate (hybrid) rocks. Structures like crenulated margins of mafic enclaves, felsic microgranular enclaves and ocelli with reaction surfaces in mafic rocks, hybrid zones at mafic-felsic contacts, back-veining and mafic flows in the granitic host imply magma mingling phenomena. Textural features like quartz and titanite ocelli, acicular apatite, rapakivi and anti-rapakivi feldspar intergrowths, oscillatory zoned plagioclase, plagioclase with resorbed core and intact rim, resorbed crystals, mafic clots and mineral transporting veins are interpreted as evidence of magma mixing. Three distinct hybridized rocks have formed due to varied interactions of the intruding mafic magma with the felsic host, which include porphyritic diorite, mingled rocks and intermediate rocks containing felsic ocelli. Geochemical signatures confirm that the hybrid rocks present in the study area are mixing products formed due to the interaction of mafic and felsic magmas. Physical parameters like temperature, viscosity, glass transition temperature and fragility calculated for different rock types have been used to model the relative contributions of mafic and felsic end-member magmas in forming the porphyritic diorite. From textural and geochemical investigations it appears that the GFD was a partly solidified magma chamber when mafic magma intruded it leading to the formation of a variety of hybrid rock types.

Laboratory studies of crystal growth in magma

NASA Astrophysics Data System (ADS)

Hammer, J. E.; Welsch, B. T.; First, E.; Shea, T.

2012-12-01

The proportions, compositions, and interrelationships among crystalline phases and glasses in volcanic rocks cryptically record pre-eruptive intensive conditions, the timing of changes in crystallization environment, and the devolatilization history of eruptive ascent. These parameters are recognized as important monitoring tools at active volcanoes and interpreting geologic events at prehistoric and remote eruptions, thus motivating our attempts to understand the information preserved in crystals through an experimental appoach. We are performing laboratory experiments in mafic, felsic, and intermediate composition magmas to study the mechanisms of crystal growth in thermochemical environments relevant to volcanic environments. We target features common to natural crystals in igneous rocks for our experimental studies of rapid crystal growth phenomena: (1) Surface curvature. Do curved interfaces and spongy cores represent evidence of dissolution (i.e., are they corrosion features), or do they record the transition from dendritic to polyhedral morphology? (2) Trapped melt inclusions. Do trapped liquids represent bulk (i.e., far-field) liquids, boundary layer liquids, or something intermediate, depending on individual species diffusivity? What sequence of crystal growth rates leads to preservation of sealed melt inclusions? (3) Subgrain boundaries. Natural phenocrysts commonly exhibit tabular subgrain regions distinguished by small angle lattice misorientations or "dislocation lamellae" and undulatory extinction. Might these crystal defects be produced as dendrites undergo ripening? (4) Clusters. Contacting clusters of polymineralic crystals are the building blocks of cumulates, and are ubiquitous features of mafic volcanic rocks. Are plagioclase and clinopyroxene aligned crystallographically, suggesting an epitaxial (surface energy) relationship? (5) Log-normal size distribution. What synthetic cooling histories produce "natural" distributions of crystal sizes, and are phenocrystic textures uniquely attributed to staged cooling? In addition, we seek to explore the limitations of the experimental approach. Which aspects of natural crystallization sequences are adequately reproduced in experimental charges, and which are compromised by the obligatory reduced temporal and spatial scales of crystal growth experiments? What are the implications of synthetic starting materials and thermal pre-treatments for nucleation, growth, heterophase equilibria, and textural maturation?

Ladder Structures and Magnetic Surveys: New Insights into the Near Surface, Three-Dimensional Shape and Orientation of Plutonic Structures in the Tuolumne Intrusive Suite, Yosemite National Park, California

NASA Astrophysics Data System (ADS)

Boyd, J. D.

2017-12-01

The study of pluton emplacement and growth history offers a window into the evolution of the continental crust. Plutons, however, are often largely homogeneous in outcrop, lacking reliable structural markers for tracking their emplacement and growth through time. The ladder structures exposed on the glacially polished surfaces of the Tuolumne Intrusive Suite (TIS) in Yosemite National Park, California are an exception. Ladder structures (LS) are eye-catching concentrations of alternating mafic and felsic mineral assemblages in dominantly cresent-shaped, meter to sub-meter scale bands in outcrop that locally terminate into a mafic band forming a circular-shaped enclosure. Their geochemistry and modal mineralogy diverge sharply from host rock trends with large quantities of magnetite, titanite, and zircon in the mafic assemblages. The limited exposure of LS in outcrops has led to much debate as to their true geometries and orientations. The high concentration of magnetite in the LS is fortuitous in that it allows these features to be investigated by magnetic techniques. The preliminary results of new high resolution magnetic surveys of these LS are presented here. A grid of total magnetic intensity (TMI) was collected across the ladder structures. The TMI's were then inverted and modeled to determine the orientation of the magnetic bodies with depth using PyGMI freeware. With sufficient contrast in the magnetic susceptibility (Km) between the feature being imaged and the host rock, meter to sub-meter scale features can be resolved. The average Km of the LS mafic bands and the host rock is approximately 200-850 x10-3 and 15-20×10-3 SI units respectively. These measurements along with oriented samples were collected to determine input parameters (e.g. anisotropy and remanence) for the geocellular model used in this study.

Exhuming Crater in Northeast Arabia

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-563, 3 December 2003

The upper crust of Mars is layered, and interbedded with these layers are old, filled and buried meteor impact craters. In a few places on Mars, such as Arabia Terra, erosion has re-exposed some of the filled and buried craters. This October 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example. The larger circular feature was once a meteor crater. It was filled with sediment, then buried beneath younger rocks. The smaller circular feature is a younger impact crater that formed in the surface above the rocks that buried the large crater. Later, erosion removed all of the material that covered the larger, buried crater, except in the location of the small crater. This pair of martian landforms is located near 17.6oN, 312.8oW. The image covers an area 3 km (1.9 mi) wide and is illuminated from the lower left.

UGTA Photograph Database

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

NSTec Environmental Restoration

One of the advantages of the Nevada Test Site (NTS) is that most of the geologic and hydrologic features such as hydrogeologic units (HGUs), hydrostratigraphic units (HSUs), and faults, which are important aspects of flow and transport modeling, are exposed at the surface somewhere in the vicinity of the NTS and thus are available for direct observation. However, due to access restrictions and the remote locations of many of the features, most Underground Test Area (UGTA) participants cannot observe these features directly in the field. Fortunately, National Security Technologies, LLC, geologists and their predecessors have photographed many of these featuresmore » through the years. During fiscal year 2009, work was done to develop an online photograph database for use by the UGTA community. Photographs were organized, compiled, and imported into Adobe® Photoshop® Elements 7. The photographs were then assigned keyword tags such as alteration type, HGU, HSU, location, rock feature, rock type, and stratigraphic unit. Some fully tagged photographs were then selected and uploaded to the UGTA website. This online photograph database provides easy access for all UGTA participants and can help “ground truth” their analytical and modeling tasks. It also provides new participants a resource to more quickly learn the geology and hydrogeology of the NTS.« less

Thermal infrared (2.5-13.5 μm) spectroscopic remote sensing of igneous rock types on particulate planetary surfaces

USGS Publications Warehouse

Salisbury, John W.; Walter, Louis S.

1989-01-01

Fundamental molecular vibration bands are significantly diminished by scattering. Thus such bands in spectra of fine particulate regoliths (i.e., dominated by <5-μm particles), or regoliths displaying a similar scale of porosity, are difficult to use for mineralogical or rock type identification. Consequently, other spectral features have been sought that may be more useful in spectroscopic remote sensing of composition. We find that mineralogical information is retained in overtones and combination tones of the fundamental molecular vibrations in the 3.0- to 7.0-μm region, but that relatively few minerals have a sufficiently distinctive band structure to be unambiguously identified with currently available techniques. More significantly, identification of general rock type, as defined by the SCFM chemical index (SCFM = SiO2/SiO2 + CaO + FeO + MgO), is possible using spectral features associated with the principal Christiansen frequency and with a region of relative transparency between the Si-O stretching and bending bands. However, environmental factors may affect the appearance and wavelengths of these features. Finally, prominent absorption bands may result from the presence of relatively small amounts of water, hydroxyl or carbonate, because absorption bands exhibited by these materials in the 2.7- to 4.0-μm region, where silicate spectra are otherwise featureless, increase strongly in spectral contrast with decreasing particle size. Such materials are thus detectable in very small amounts in a particulate regolith composed predominantly of silicate minerals.

Aquifer characteristics near cuestas and their relation to rock tensile strength

USGS Publications Warehouse

Morin, Roger H.; Schulz, William; LoCoco, James

2010-01-01

Along the northeast coast of North America, extensional tectonic processes have generated lithologic and topographic features that are common to several rift basins. A cap of igneous rock overlies sedimentary rock to form a cuesta with both rock types exposed along a steep ridge flank. Field studies investigating the near‐surface hydrogeologic properties of the caprocks at several of these sites have reported a narrow range of results; some fractured rocks form modest aquifers whereas others do not. To examine this behavior in terms of geomechanical responses to gravitational stresses imposed near ridges, a finite‐element model is presented that incorporates the geometry of a ridge‐valley configuration and its major structural elements. Model simulations reflect the effects of a lack of buttressing along free faces and a contrast in Poisson's ratios between the superposed igneous and sedimentary rocks. Three‐dimensional Mohr's circles are constructed from principal stress magnitudes and directions to evaluate the response of individual fracture planes to this stress state. Results depict a predominantly tensional stress environment where numerous pre‐existing fractures may be favorably aligned for opening and enhanced caprock permeability. However, the lack of conclusive field evidence to support this hypothesis suggests that the in situ tensile strength of the fractured rock mass is substantial enough to resist failure by shear or dilation, and that critically‐stressed fracture planes do not convey large volumes of groundwater in ridge‐valley settings.

The Apollo 15 X-ray fluorescence experiment

NASA Technical Reports Server (NTRS)

Adler, I.; Trombka, J.; Gerard, J.; Schmadebeck, R.; Lowman, P.; Blodgett, H.; Yin, L.; Eller, E.; Lamothe, R.; Gorenstein, P.

1972-01-01

The CSM spectrometric data on the lunar surface with respect to its chemical composition are presented for Al, Mg, and Si as Al/Si and Mg/Si ratios for the various features overflow by the spacecraft. The lunar surface measurements involved observations of the intensity and characteristic energy distribution of the secondary or fluorescent X-rays produced by the interaction of solar X-rays with the lunar surface. The results showed that the highlands and maria are chemically different, with the highlands having considerably more Al and less Mg than the maria. The mare-highland contact is quite sharp and puts a limit on the amount of horizontal transport of material. The X-ray data suggest that the dominant rock type of the lunar highlands is a plagioclase-rich pyroxene bearing rock, probably anorthositic gabbro or feldspathic basalt. Thus the moon appears to have a widespread differentiated crust (the highlands) systematically richer in Al and lower in Mg than the maria. This crust is pre-mare and may represent the first major internal differentiation of the moon.

[Ecological basis of epiphytic Dendrobium officinale growth on cliff].

PubMed

Liu, Xiu-Juan; Zhu, Yan; Si, Jin-Ping; Wu, Ling-Shang; Cheng, Xue-Liang

2016-08-01

In order to make Dendrobium officinale return to the nature, the temperature and humidity in whole days of the built rock model with different slopes and aspects in the natural distribution of wild D. officinale in Tianmu Mountain were recorded by MH-WS01 automatic recorder. The results showed that the slope has a significant impact on the extreme temperature on the surface of the rocks. In summer, the extreme temperature on the surface of horizontal or soft rock can reach to 69.4 ℃, while the temperatures were lower than 50 ℃ on the vertical rock. In winter, the temperatures on the surface of vertical rock were higher and the low temperature duration was shorter than those on the horizontal or soft rock. Also, the humidity of the rocks was significantly influenced by the slope. The monthly average humidity on the surface of vertical rock was above 80%RH. Furthermore, the aspect had a significant impact on the temperature and humidity on the surface of the rocks, but had no significant effect on the daily mean temperature and extreme temperature on the surface of vertical rock. Therefore, the slope affects the survival of D. officinale by affecting the extreme temperature of rocks and affects the growth of D. officinale by affecting the humidity. The choice of slope is the key to the success of cliff epiphytic cultivation for D. officinale. Copyright© by the Chinese Pharmaceutical Association.

Initial Lithologic Mapping Results Using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Data

NASA Astrophysics Data System (ADS)

Rowan, L. C.; Mars, J. C.

2001-05-01

Initial analysis of ASTER data of selected areas in the Western United States shows that many important lithologic units can be mapped on the basis of spectral reflectance and spectral emittance. ASTER's most important attributes are 9 bands which record reflected-solar energy with 15 meter- and 30 meter-resolution; 5 bands of emitted energy at 90 meter- resolution; 15 meter-resolution stereoscopic images; and repetitive coverage. Particularly useful 'on-demand' ASTER data products include surface reflectance and surface emissivity images, and digital elevation models (DEM). In the solar-reflected wavelength region (0.4 to 2.5 micrometers), clays, carbonates, hydrous sulphate, and iron-oxide minerals exhibit diagnostic absorption features, whereas the emitted wavelength region (8 to 14 micrometers) provides critical information about anhydrous rock-forming minerals, such as quartz and feldspars, which lack diagnostic absorption features in the solar-reflected region. The Mountain Pass, Calf., Goldfield, Nev., and Virginia Range, Nev. study areas comprise a wide range of lithologic types for evaluating ASTER data. Calibration of the 3 bands recorded in the 0.52 to 0.86 micrometer wavelength region and the 6 bands in the 1.60 to 2.43 micrometer region was improved beyond the 'on-demand' surface reflectance standard product by using in situ spectral reflectance measurements of homogeneous field sites. Validation of this calibration was based on comparisons with spectra from calibrated AVIRIS data, and with additional field measurements. Lithologic mapping based on ASTER bands 1-9 was conducted by using endmember spectra from the image as reference spectra in matched-filter processing. The results were thresholded to display the pixels with the best match for each endmember. The results in these study areas show that Muscovite Group minerals (muscovite, illite, kaolinite) can be mapped over broad reasonably well exposed areas, and that the most intense absorption features occur in hydrothermally altered rocks. In the Mountain Pass area a few exposures containing Fe-muscovite were distinguished from the more extensive Al-mucovite-bearing rocks and soils. Advanced-argillic alteration minerals (alunite, dickite) were detected in the Goldfield mining district and in the Virginia Range. Carbonate Group minerals (calcite, dolomite) were mapped in extensive exposures in the thrust belt of the Mountain Pass area, and well exposed dolomite was distinguished from limestone in several areas. Although skarn deposits consist mainly of calcite and dolomite, their spectral shape in ASTER bands 1-9 is significantly different than typical limestone and dolomite spectra because of the presence of epidote, garnet and chrysotile in the skarn deposits. Mg-OH-bearing minerals (chlorite, biotite, hornblende) proved to be more difficult to map, although generally they were not confused with minerals of the Carbonate Group. Ferric-iron Group minerals were mapped by using a band2/band1 ratio image. Analysis of the surface emissivity standard image products relied on identification of endmember-image spectra by using the pixel-purity index procedure in the ENVI software package, and matched-filter processing. Silica-rich rocks and silica-poor rocks were recognized readily in decorrelation-stretch images, as well as matched-filter endmember images, and 2 intermediate categories were distinguished in most areas.

Tafoni - A Llink Between Mars and Earth

NASA Astrophysics Data System (ADS)

Iacob, R. H.; Iacob, C. E.

2013-12-01

Remarkable rock erosion structures on the planetary surface, tafoni represent an important instrument for investigating the specific environmental conditions causing such rock formations. From simple cavities to refined honeycomb or other intricate patterns, tafoni are a reflection of the complex interaction between the rock structure and the environmental factors. On the genesis of tafoni, there is no unique breakdown mechanism at work, but a multitude of physical and chemical processes developing over time. However, some of these formation mechanisms are typically predominant. Tafoni can be found on a variety of rock substrates, from sandstone and vesicular lava rocks to granite and basalt, and in a variety of environments, from wet coastal areas to the extreme dry zones of hot deserts, high plateaus or frozen lands of Antarctica. During various NASA missions, tafoni were also identified on rock formations on Mars. Comparative study of the environmental conditions leading to the formation of tafoni on Earth and Mars can help explain past and present surface erosion mechanisms on the Red Planet. The mechanisms responsible for tafoni formation on Earth include wind erosion, exfoliation, frost shattering, and, in the majority of cases, salt weathering. Microclimate variations of temperature, evaporation of salt water, disaggregation of mineral grains, as well as sandblasting, are among most common contributors that initiate the pitting of the rock surface, giving way to further development of tafoni alveoli, cavities and other erosion patterns. Dissolution of calcium carbonates and siliceous cements, or hydration of feldspars, are representative examples of tafoni erosion involving rain water, sea water or air moisture. Live organisms and biochemical processes are significant contributors to the formation and evolution of tafoni, especially in humid or water reach environments. In many instances, tafoni reflect erosion mechanism specific to environmental conditions that no longer exist. NASA's current Mars Science Laboratory mission offers exceptional opportunities to perform a comparative study between tafoni formations on Mars and those on Earth. The present mission of Curiosity at Gale Crater, benefiting not only from the most advanced technology for in-situ investigations but also from a terrain rich in rock breakdown features, was able to reveal new tafoni formations. Gale Crater's landscape presents a variety of surface erosion elements, witnesses of major planetary transformations suffered by Mars during the past 3 billion years. While the wind and sand-blasting erosion are the most recent causes of the surface erosion at Gale Crater, leading to the smoothing, thinning, exfoliation and piercing of various rock layers, other geological formations such as alluvial fans, moat areas, gravel sediments, round shaped mounds and toadstool formations demonstrate that liquid water was vigorously shaping the surface of Mars billions of years ago. In such a context, the study of tafoni formations revealed during Curiosity's trek from Bradbury Landing through the Glenelg area of Gale Crater, will help advance the understanding of the Martian past and present environment, providing scenarios for the evolution of the Red Planet. The presentation contains various images of tafoni samples from Mars and Earth, explaining by similitude presumptive weathering mechanisms on Mars.

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.

Experimental Estimation Of Energy Damping During Free Rocking Of Unreinforced Masonry Walls. First Results

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

Sorrentino, Luigi; Masiani, Renato; Benedetti, Stefano

2008-07-08

This paper presents an ongoing experimental program on unreinforced masonry walls undergoing free rocking. Aim of the laboratory campaign is the estimation of kinetic energy damping exhibited by walls released with non-zero initial conditions of motion. Such energy damping is necessary for dynamic modelling of unreinforced masonry local mechanisms. After a brief review of the literature on this topic, the main features of the laboratory tests are presented. The program involves the experimental investigation of several parameters: 1) unit material (brick or tuff), 2) wall aspect ratio (ranging between 14.5 and 7.1), 3) restraint condition (two-sided or one-sided rocking), andmore » 4) depth of the contact surface between facade and transverse walls (one-sided rocking only). All walls are single wythe and the mortar is pozzuolanic. The campaign is still in progress. However, it is possible to present the results on most of the mechanical properties of mortar and bricks. Moreover, a few time histories are reported, already indicating the need to correct some of the assumptions frequent in the literature.« less

Measurements of acoustic surface waves on fluid-filled porous rocks

NASA Astrophysics Data System (ADS)

Adler, Laszlo; Nagy, Peter B.

1994-09-01

Novel experimental techniques to measure ultrasonic velocity and attenuation of surface waves on fluid-filled porous natural rocks are presented. Our experimental results are consistent with the theoretical predictions of Feng and Johnson (1983). Depending on the interface conditions, i.e., whether the surface pores are open or closed, pseudo-Rayleigh, pseudo-Stoneley, and/or Stoneley surface waves may exist on fluid-saturated rocks with closed 'slow' surface wave (true Stoneley mode) on fluid-filled porous rocks with closed surface pores. The velocity and attenuation of the 'slow' surface mode may be used to assess the dynamic permeabilty of porous formations.

Spectral variations in rocks and soils containing ferric iron hydroxide and(or) sulfate minerals as seen by AVIRIS and laboratory spectroscopy

USGS Publications Warehouse

Rockwell, Barnaby W.

2004-01-01

Analysis of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data covering the Big Rock Candy Mountain area of the Marysvale volcanic field, west-central Utah, identified abundant rocks and soils bearing jarosite, goethite, and chlorite associated with volcanic rocks altered to propylitic grade during the Miocene (2321 Ma). Propylitically-altered rocks rich in pyrite associated with the relict feeder zones of convecting, shallow hydrothermal systems are currently undergoing supergene oxidation to natrojarosite, kaolinite, and gypsum. Goethite coatings are forming at the expense of jarosite where most pyrite has been consumed through oxidation in alluvium derived from pyrite-bearing zones. Spectral variations in the goethite-bearing rocks that resemble variations found in reference library samples of goethites of varying grain size were observed in the AVIRIS data. Rocks outside of the feeder zones have relatively low pyrite content and are characterized by chlorite, epidote, and calcite, with local copper-bearing quartz-calcite veins. Iron-bearing minerals in these rocks are weathering directly to goethite. Laboratory spectral analyses were applied to samples of iron-bearing rock outcrops and alluvium collected from the area to determine the accuracy of the AVIRIS-based mineral identification. The accuracy of the iron mineral identification results obtained by analysis of the AVIRIS data was confirmed. In general, the AVIRIS analysis results were accurate in identifying medium-grained goethite, coarse-grained goethite, medium- to coarse-grained goethite with trace jarosite, and mixtures of goethite and jarosite. However, rock fragments from alluvial areas identified as thin coatings of goethite with the AVIRIS data were found to consist mainly of medium- to coarse-grained goethite based on spectral characteristics in the visible and near-infrared. To determine if goethite abundance contributed to the spectral variations observed in goethite-bearing rocks with AVIRIS data, a laboratory experiment was performed in which spectra were acquired of a goethite-bearing rock while progressively decreasing the areal abundance of the rock with respect to a background of white, fine-grained quartz sand. This experiment found that, with decreasing material abundance, the crystal field absorption feature of goethite near 1.0 micron decreases in depth and narrows more from the long wavelength side of the feature than from the short wavelength side, as is the case in goethite reference spectra as grain size decreases from coarse to fine. In the Marysvale study area, goethite-bearing alluvium downgradient from source outcrops tends to be identified as finer-grained or thin coatings of goethite due to the minerals presence in lesser abundance. The goethite-bearing alluvium is a closer match to reference spectra of thin coatings of goethite even though the actual grain size of the contained goethite fragments is medium to coarse grained, the same on average as that from the source outcrops. Coarser-grained goethite most likely will be correctly identified in areas of greater goethite abundance proximal to jarosite-bearing source rock where the surface is relatively free of goethite-free soil components and vegetation that corrupt the goethite spectral response. When analysis of imaging spectroscopy data is performed using reference spectra of iron minerals of varying grain sizes and mixed compositions, the results are useful not only for purposes of mineral identification, but also for distinguishing goethite-bearing outcrop from alluvial surfaces with similar mineralogy, providing valuable information for geologic, geomorphologic, mineral exploration, and environmental assessment studies.

Geologic Surface Effects of Underground Nuclear Testing, Buckboard Mesa, Climax Stock, Dome Mountain, Frenchman Flat, Rainier/Aqueduct Mesa, and Shoshone Mountain, Nevada Test Site, Nevada

USGS Publications Warehouse

Grasso, Dennis N.

2003-01-01

Surface effects maps were produced for 72 of 89 underground detonations conducted at the Frenchman Flat, Rainier Mesa and Aqueduct Mesa, Climax Stock, Shoshone Mountain, Buckboard Mesa, and Dome Mountain testing areas of the Nevada Test Site between August 10, 1957 (Saturn detonation, Area 12) and September 18, 1992 (Hunters Trophy detonation, Area 12). The ?Other Areas? Surface Effects Map Database, which was used to construct the maps shown in this report, contains digital reproductions of these original maps. The database is provided in both ArcGIS (v. 8.2) geodatabase format and ArcView (v. 3.2) shapefile format. This database contains sinks, cracks, faults, and other surface effects having a combined (cumulative) length of 136.38 km (84.74 mi). In GIS digital format, the user can view all surface effects maps simultaneously, select and view the surface effects of one or more sites of interest, or view specific surface effects by area or site. Three map layers comprise the database. They are: (1) the surface effects maps layer (oase_n27f), (2) the bar symbols layer (oase_bar_n27f), and (3) the ball symbols layer (oase_ball_n27f). Additionally, an annotation layer, named 'Ball_and_Bar_Labels,' and a polygon features layer, named 'Area12_features_poly_n27f,' are contained in the geodatabase version of the database. The annotation layer automatically labels all 295 ball-and-bar symbols shown on these maps. The polygon features layer displays areas of ground disturbances, such as rock spall and disturbed ground caused by the detonations. Shapefile versions of the polygon features layer in Nevada State Plane and Universal Transverse Mercator projections, named 'area12_features_poly_n27f.shp' and 'area12_features_poly_u83m.shp,' are also provided in the archive.

Signs of Soft-Sediment Deformation at 'Slickrock'

NASA Technical Reports Server (NTRS)

2004-01-01

Geological examination of bedding textures indicates three stratigraphic units in an area called 'Slickrock' located in the martian rock outcrop that NASA's Opportunity examined for several weeks. This is an image Opportunity took from a distance of 2.1 meters (6.9 feet) during the rover's 45th sol on Mars (March 10, 2004) and shows a scour surface or ripple trough lamination. These features are consistent with sedimentation on a moist surface where wind-driven processes may also have occurred.

[figure removed for brevity, see original site] Figure 1

In Figure 1, interpretive blue lines indicate boundaries between the units. The upper blue line may coincide with a scour surface. The lower and upper units have features suggestive of ripples or early soft-sediment deformation. The central unit is dominated by fine, parallel stratification, which could have been produced by wind-blown ripples.

[figure removed for brevity, see original site] Figure 2

In Figure 2, features labeled with red letters are shown in an enlargement of portions of the image. 'A' is a scour surface characterized by truncation of the underlying fine layers, or laminae. 'B' is a possible soft-sediment buckling characterized by a 'teepee' shaped structure. 'C' shows a possible ripple beneath the arrow and a possible ripple cross-lamination to the left of the arrow, along the surface the arrow tip touches. 'D' is a scour surface or ripple trough lamination. These features are consistent with sedimentation on a moist surface where wind-driven processes may also have occurred.

Textural evolution of partially-molten planetary materials in microgravity

NASA Technical Reports Server (NTRS)

Watson, E. B.

1987-01-01

Recent Earth-based experiments examining the textural evolution of partially-molten rocks have revealed two important ways in which surface energy considerations affect magma. An initial experimental program addressing surface-energy effects on partially-molten materials in microgravity would involve simple, isothermal treatment of natural samples (meteorites, perioditic komatiite) at preselected temperatures in the melting range. Textural evolution would be assessed by time studies in which the only experiment variable would be run duration. Textural characterization of each sample would be done by quenching, recover, and sectioning for generally later, computer-aided interpretation of features.

Terrain analysis of the racetrack basin and the sliding rocks of Death Valley

USGS Publications Warehouse

Messina, P.; Stoffer, P.

2000-01-01

The Racetrack Playa's unusual surface features known as sliding rocks have been the subject of an ongoing debate and several mapping projects for half a century, although the causative mechanism remains unresolved. Clasts ranging in volume from large pebbles to medium boulders have, unwitnessed, maneuvered around the nearly flat dry lake over considerable distances. The controversy has persisted partly because eyewitness accounts of the phenomenon continue to be lacking, and the earlier mapping missions were limited in method and geographic range. In July 1996, we generated the first complete map of all observed sliding rock trails by submeter differential Global Positioning System (DGPS) mapping technology. The resulting map shows 162 sliding rocks and associated trails to an accuracy of approximately 30 cm. Although anemometer data are not available in the Racetrack wilderness, wind is clearly a catalyst for sliding rock activity; an inferred wind rose was constructed from DGPS trail segment data. When the entire trail network is examined in plan, some patterns emerge, although other (perhaps expected relations) remain elusive: terrain analysis of the surrounding topography demonstrates that the length and morphology of trails are more closely related to where rocks rested at the onset of motion than to any physical attribute of the rocks themselves. Follow-up surveys in May 1998, May 1999, August 1999, and November 1999 revealed little modification of the July, 1996 sliding rock configuration. Only four rocks were repositioned during the El Nino winter of 1997-1998, suggesting that activity may not be restricted to winter storms. (C) 2000 Elsevier Science B.V. All rights reserved.

A brief geologic history of Volusia County, Florida

USGS Publications Warehouse

German, Edward R.

2009-01-01

Volusia County is in a unique and beautiful setting. This Florida landscape is characterized by low coastal plains bordered by upland areas of sandy ridges and many lakes. Beautiful streams and springs abound within the vicinity. Underneath the land surface is a deep layer of limestone rocks that stores fresh, clean water used to serve drinking and other needs. However, the landscape and the subsurface rocks have not always been as they appear today. These features are the result of environmental forces and processes that began millions of years ago and are still ongoing. This fact sheet provides a brief geologic history of the Earth, Florida, and Volusia County, with an emphasis on explaining why the Volusia County landscape and geologic structure exists as it does today.

Geochemical and spectral characterization of naturally altered rock surfaces

NASA Technical Reports Server (NTRS)

Chang, L. L. Y.; Sommer, S. E.; Buckingham, W. F.

1981-01-01

The possibility of using the visible-near infrared region for compositional analysis of remotely sensed rock surfaces is studied. This would allow mapping rock type both on the Earth's surface and on other planetary surfaces. Reflectance spectroscopy, economic geology, optical depth determination, and X-ray diffraction mineralogy are discussed.

Evaluation of ASR potential of quartz-rich rocks by alkaline etching of polished rock sections

NASA Astrophysics Data System (ADS)

Šachlová, Šárka; Kuchařová, Aneta; Pertold, Zdeněk; Přikryl, Richard

2015-04-01

Damaging effect of alkali-silica reaction (ASR) on concrete structures has been observed in various countries all over the World. Civil engineers and real state owners are demanding reliable methods in the assessment of ASR potential of aggregates before they are used in constructions. Time feasible methods are expected, as well as methods which enable prediction of long-term behaviour of aggregates in concrete. The most frequently employed accelerated mortar bar test (AMBT) quantifies ASR potential of aggregates according to the expansion values of mortar bars measured after fourteen days testing period. Current study aimed to develop a new methodical approach facilitating identification and quantification of ASR potential of aggregates. Polished rock sections of quartz and amorphous SiO2 (coming from orthoquartzite, quartz meta-greywacke, pegmatite, phyllite, chert, and flint) were subjected to experimental leaching in 1M NaOH solution at 80°C. After 14 days of alkaline etching, the rock sections were analyzed employing scanning electron microscope combined with energy dispersive spectrometer. Representative areas were documented in back scattered electron (BSE) images and measured using fully-automatic petrographic image analysis (PIA). Several features connected to alkaline etching were observed on the surface of polished rock sections: deep alkaline etching, partial leach-out of quartz and amorphous particles, alkaline etching connected to quartz grain boundaries, and alkaline etching without any connection to grain boundaries. All features mentioned above had significant influence on grey-scale spectrum of BSE images. A specific part of the grey-scale spectrum (i.e. grey-shade 0-70) was characteristic of areas affected by alkaline etching (ASR area). By measuring such areas we quantified the extent of alkaline etching in studied samples. Very good correlation was found between the ASR area and ASR potential of investigated rocks measured according to the standard AMBT (folowing ASTM C1260). The etching experiment is regarded to be feasible method to quantify ASR potential of quartz- (resp. SiO2-) rich rocks. Employement of the method: (1) decreases potential error from less experienced operator; (2) minimizes the volume of the rock need to be analyzed; (3) enables to visualize microscopic features where ASR originates; and (4) enables to identify alkali-reactive components in the rocks. The main disadvatage of the method is regarded in the restriction to quartz- (resp. SiO2-) rich rocks. If other minerals are included in the rocks their role in ASR should be considered. These minerals can be excluded from the analysis in case they are not reactive and if their content is very low (e.g. accesory minerals). If the minerals contribute to ASR (e.g. albite, micas), these mineral phases should be included in the analysis. Then the application of PIA needs to be modified in respect to different grey shades of individual minerals.

Thrust-induced collapse of mountains-an example from the "Big Bend" region of the San Andreas Fault, western transverse ranges, California

USGS Publications Warehouse

Kellogg, Karl S.

2005-01-01

Mount Pinos and Frazier Mountain are two prominent mountains just south of the San Andreas fault in the western Transverse Ranges of southern California, a region that has undergone rapid Quaternary contraction and uplift. Both mountains are underlain, at least in part, by thrusts that place granitic and gneissic rocks over sedimentary rocks as young as Pliocene. Broad profiles and nearly flat summits of each mountain have previously been interpreted as relicts of a raised erosion surface. However, several features bring this interpretation into question. First, lag or stream gravels do not mantle the summit surfaces. Second, extensive landslide deposits, mostly pre?Holocene and deeply incised, mantle the flanks of both mountains. Third, a pervasive fracture and crushed?rock network pervades the crystalline rocks underlying both mountains. The orientation of the fractures, prominent in roadcuts on Mount Pinos, is essentially random. 'Hill?and?saddle' morphology characterizes ridges radiating from the summits, especially on Mount Pinos; outcrops are sparse on the hills and are nonexistent in the saddles, suggesting fractures are concentrated in the saddles. Latest movement on the thrusts underlying the two mountain massifs is probably early Quaternary, during which the mountains were uplifted to considerably higher (although unknown) elevations than at present. A model proposes that during thrusting, ground accelerations in the hanging wall, particularly near thrust tips, were high enough to pervasively fracture the hanging?wall rocks, thereby weakening them and producing essentially an assemblage of loose blocks. Movement over flexures in the fault surface accentuated fracturing. The lowered shear stresses necessary for failure, coupled with deep dissection and ongoing seismic activity, reduced gravitational potential by spreading the mountain massifs, triggering flanking landslides and producing broad, flat?topped mountains. This study developed from mapping in the western Transverse Ranges as part of the U.S. Geological Survey's Southern California Areal Mapping Project (SCAMP).

Dike emplacement on Venus and on earth

NASA Technical Reports Server (NTRS)

Mckenzie, Dan; Mckenzie, James M.; Saunders, R. S.

1992-01-01

Attention is given to long linear features visible in SAR images of the surface of Venus. They are shallow graben a few kilometers across. Calculations show that dike emplacement can account for such features if the top of the dikes is a few kilometers below the surface of the planet. The dikes are often curved near their probable sources, and the magnitude of the regional stress field estimated from this curvature is about 3 MPa, or similar to that of earth. On both Venus and earth, dikes often form intersecting patterns. Two-dimensional calculations show that this behavior can occur only if the stress field changes with time. Transport of melt over distances as large as 2000 km in dikes whose width is 30 m or more occurs in some continental shields on earth and can also account for linear features on Venus that extend for comparable distances. Such transport is possible because the viscosity and thermal conductivity of both the melt and the wall rock are small.

Skylab

NASA Image and Video Library

1973-09-01

This Earth Resource Experiment Package (EREP) photograph of the Uncompahgre area of Colorado was electronically acquired in September of 1973 by the Multi-spectral Scarner, Skylab Experiment S192. EREP images were used to analyze the vegetation conditions and landscape characteristic of this area. Skylab's Earth sensors played the dual roles of gathering information about the planet and perfecting instruments and techniques for future satellites and manned stations. An array of six fixed cameras, another for high resolution, and the astronauts' handheld cameras photographed surface features. Other instruments, recording on magnetic tape, measured the reflectivity of plants, soils, and water. Radar measured the altitude of land and water surfaces. The sensors' objectives were to survey croplands and forests, identify soils and rock types, map natural features and urban developments, detect sediments and the spread of pollutants, study clouds and the sea, and determine the extent of snow and ice cover.

Chemical and physical characterisation of water in an alpine permafrost area (Col d'Olen LTER site, Italian NW-Alps)

NASA Astrophysics Data System (ADS)

Giardino, Marco; Colombo, Nicola; Fratianni, Simona; Guenzi, Diego; Acquaotta, Fiorella; Perotti, Luigi; Freppaz, Michele; Godone, Danilo; Said Pullicino, Daniel; Martin, Maria; Viglietti, Davide; Gorra, Roberta; Mania, Ilaria; Viviano, Gaetano; Salerno, Franco; Balestrini, Raffaella

2015-04-01

High altitude areas in the Alps are characterised by the permafrost environment, which reacts sensitively to climate change. During the last decades several studies on alpine permafrost-related hazards have been performed, but few studies have focused on the geochemical content of the water that drains permafrost areas or outflow from rock glaciers (Williams et al., 2006; Thies et al., 2007; Krainer et al., 2011). Rock glaciers have physical and chemical influences on interflowing waters and their discharge can be highly enriched in solutes. For example, unexpected high nickel and manganese concentrations exceeding the EU limits for drinking water have been recently reported in some studies investigating rock glacier discharges (Ilyashuk et al., 2014). The present study aims to evaluate rock glacier solute fluxes into a high altitude lake in the Italian NW-Alps (Col d'Olen LTER site, Aosta Valley) in order to understand the impact of climate parameters on alpine permafrost, in particular the effects of permafrost ice melt on the water quality of mountain headwaters. This objective has been achieved through an integrated-multidisciplinary research programme involving climate analysis, rock glacier ground surface temperature investigation, water physiochemical and microbiological analyses. Nine automatic and three manned weather stations located in the surrounding areas of the rock glacier (radius: 12 km) have been used to study the relationships between climatic parameters and permafrost dynamics. Moreover, meteorological data have been collected by installing portable instruments in situ, integrated in a Mini Automatic Weather Station. To investigate the correlations between physiochemical features of water and the thermal state of the rock glacier surface, the ground temperature monitoring has been conducted. Temperature dataloggers have been buried 5/10 cm into the ground, regularly distributed on the rockglacier surface and in few surrounding sites. Total Station was used to achieve position for each datalogger and differential GNSS was used to acquire global geographic coordinates with centimetric precision in order to accurately interpolate ground temperature data grid. Water quality monitoring was conducted using a multiparameter spectrometer probe. In particular, NO3-Neq, DOCeq, TOCeq and turbidity were analysed, and UV-visible absorbance spectra (220-720 nm) were recorded every three hours during summer and early autumn seasons. Water sampling in the rock glacier lake (and related inflows) was conducted on weekly basis starting with the initiation of snow melt runoff until freeze-up in the early autumn. Moreover, the ablation water of the Indren Glacier (located in the study area) has been analysed in order to use it as reference data. Water samples have been analysed for anions, cations, trace elements, nutrient content (TOC, DOC, TDP, DOP, TDN, DON), EC (Electrical Conductivity), Eh (redox potential) and pH. Finally, in order to assess microbial diversity and abundance of communities, functionally related to ecosystem nutrient dynamics, diversity and abundance of microbial communities were analysed. The fine material in the permafrost feature has been characterised through the determination of Ntot, Corg, N forms and heavy metals.

3D granular deposits on rock avalanches: can the application of different operators and filtering techniques improve our understanding of the phenomena?

NASA Astrophysics Data System (ADS)

Longchamp, Celine; Abellan, Antonio; Derron, Marc-Henri; Jaboyedoff, Michel

2014-05-01

Rock avalanches are catastrophic events involving a great volume of material (>106 m3). The flowing mass can reach velocities up to ten meters per second and travel long distances on the order of kilometres, covering an area over 0.1 km2. These extremely destructive and uncontrollable events are very unusual in nature and the use of analogue modelling is of great importance in the understanding of the behaviour of such events. The main objective of this research is to analyse rock avalanche dynamics by means of a detailed structural analysis of the features observed in the avalanche. Data used for this research consist on 3D measurements of mass movements of different magnitudes, from decimetre level scale laboratory experiments to well-studied rock avalanches of several square kilometres magnitude, as follows: (1) Laboratory experiments are performed on a tilting plane in which a well-defined granular material is released, chute down a slope, propagate and finally stop on a horizontal surface. The deposits are then scanned by a 3D digitizer (Konica Minolta vivid 9i micro-LiDAR) in order to get a 3D geometrical model of the mass. Different grainsize (115, 545 and 2605 μm) and substratum roughness (simulate by aluminium and sandpapers with grainsize from 16 to 425 μm) were used in order to understand their influence on the motion of a granular mass; (2) A well know rock avalanche deposit, the Frank slide (Alberta, Canada), was also analysed from the available 3D LiDAR dataset. This deposit consists in a 30× 106 m3 rockslide-avalanche of Palaeozoic limestone that was widely studied by several authors before (e.g. Cruden and Hungr, 1986, Cruden and Krahn, 1973, etc). In order to better understand the fault and folding structures presented in the rock avalanche deposits, we applied a series of linear and non-linear Matlab operators and filtering techniques to the 3D datasets, including differences derivatives ('diff'), numerical gradient ('gradient'), discrete Laplacian ('del2') and median filter ('medfilt2') with different moving windows sizes (from 3x3 to 9x9 nearest neighbour). A detailed structural analysis of the deposit is performed in order to understand how the sliding mass behaves. The application of these filters on the datasets results in: (1) a precise mapping of the longitudinal and transversal displacement features observed at the surface of the deposits; and (2) a more accurate interpretation of the relative movements along the deposit (i.e. normal, strike-slip and thrust faults) by using cross-sections. Preliminary results shows how the use of filtering techniques reveal disguised features in the original point cloud and that similar displacement patterns are observable in both cases studies, regardless the size of the avalanche. Furthermore, we observed how different structural features including transversal fractures and folding patterns tend to show a constant wavelength proportional to the size of the avalanche event.

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.

Roter Kamm Impact Crater in Namibia

NASA Image and Video Library

1996-11-13

This space radar image shows the Roter Kamm impact crater in southwest Namibia. The crater rim is seen in the lower center of the image as a radar-bright, circular feature. Geologists believe the crater was formed by a meteorite that collided with Earth approximately 5 million years ago. The data were acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) instrument onboard space shuttle Endeavour on April 14, 1994. The area is located at 27.8 degrees south latitude and 16.2 degrees east longitude in southern Africa. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); and blue represents the C-band (horizontally transmitted and vertically received). The area shown is approximately 25.5 kilometers (15.8 miles) by 36.4 kilometers (22.5 miles), with north toward the lower right. The bright white irregular feature in the lower left corner is a small hill of exposed rock outcrop. Roter Kamm is a moderate sized impact crater, 2.5 kilometers (1.5 miles) in diameter rim to rim, and is 130 meters (400 feet) deep. However, its original floor is covered by sand deposits at least 100 meters (300 feet) thick. In a conventional aerial photograph, the brightly colored surfaces immediately surrounding the crater cannot be seen because they are covered by sand. The faint blue surfaces adjacent to the rim may indicate the presence of a layer of rocks ejected from the crater during the impact. The darkest areas are thick windblown sand deposits which form dunes and sand sheets. The sand surface is smooth relative to the surrounding granite and limestone rock outcrops and appears dark in radar image. The green tones are related primarily to larger vegetation growing on sand soil, and the reddish tones are associated with thinly mantled limestone outcrops. Studies of impact craters on the surface of the Earth help geologists understand the role of the impact process in the Earth's evolution, including effects on the atmosphere and on biological evolution. http://photojournal.jpl.nasa.gov/catalog/PIA00503

Shatter cones at the Keurusselkä impact structure and their relation to local jointing

NASA Astrophysics Data System (ADS)

Hasch, Maximilian; Reimold, Wolf Uwe; Raschke, Ulli; Zaag, Patrice Tristan

2016-08-01

Shatter cones are the only distinct meso- to macroscopic recognition criterion for impact structures, yet not all is known about their formation. The Keurusselkä impact structure, Finland, is interesting in that it presents a multitude of well-exposed shatter cones in medium- to coarse-grained granitoids. The allegedly 27 km wide Keurusselkä impact structure was formed about 1150 Ma ago in rocks of the Central Finland Granitoid Complex. Special attention was paid in this work to possible relationships between shatter cones and local, as well as regionally occurring, fracture or joint systems. A possible shatter cone find outside the previously suggested edge of the structure could mean that the Keurusselkä impact structure is larger than previously thought. The spacing between joints/fractures from regional joint systems was influenced by the impact, but impact-induced fractures strongly follow the regional joint orientation trends. There is a distinct relationship between shatter cones and joints: shatter cones occur on and against joint surfaces of varied orientations and belonging to the regional orientation trends. Planar fractures (PF) and planar deformation features (PDF) were found in three shatter cone samples from the central-most part of the impact structure, whereas other country rock samples from the same level of exposure but further from the assumed center lack shock deformation features. PDF occurrence is enhanced within 5 mm of shatter cone surfaces, which is interpreted to suggest that shock wave reverberation at preimpact joints could be responsible for this local enhancement of shock deformation. Some shatter cone surfaces are coated with a quasi-opaque material which is also found in conspicuous veinlets that branch off from shatter cone surfaces and resemble pseudotachylitic breccia veins. The vein-filling is composed of two mineral phases, one of which could be identified as a montmorillonitic phyllosilicate. The second phase could not be identified yet. The original composition of the fill could not be determined. Further work is required on this material. Observed joints and fractures were discussed against findings from Barringer impact crater. They show that impact-induced joints in the basement rock do not follow impact-specific orientations (such as radial, conical, or concentric).

Remote sensing for environmental site screening and watershed evaluation in Utah Mine lands - East Tintic mountains, Oquirrh mountains, and Tushar mountains

USGS Publications Warehouse

Rockwell, Barnaby W.; McDougal, Robert R.; Gent, Carol A.

2005-01-01

Imaging spectroscopy-a powerful remote-sensing tool for mapping subtle variations in the composition of minerals, vegetation, and man-made materials on the Earth's surface-was applied in support of environmental assessments and watershed evaluations in several mining districts in the State of Utah. Three areas were studied through the use of Landsat 7 ETM+ and Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data: (1) the Tintic mining district in the East Tintic Mountains southwest of Provo, (2) the Camp Floyd mining district (including the Mercur mine) and the Stockton (or Rush Valley) mining district in the Oquirrh Mountains south of the Great Salt Lake, and (3) the Tushar Mountains and Antelope Range near Marysvale. The Landsat 7 ETM+ data were used for initial site screening and the planning of AVIRIS surveys. The AVIRIS data were analyzed to create spectrally defined maps of surface minerals with special emphasis on locating and characterizing rocks and soils with acid-producing potential (APP) and acid-neutralizing potential (ANP). These maps were used by the United States Environmental Protection Agency (USEPA) for three primary purposes: (1) to identify unmined and anthropogenic sources of acid generation in the form of iron sulfide and (or) ferric iron sulfate-bearing minerals such as jarosite and copiapite; (2) to seek evidence for downstream or downwind movement of minerals associated with acid generation, mine waste, and (or) tailings from mines, mill sites, and zones of unmined hydrothermally altered rocks; and (3) to identify carbonate and other acid-buffering minerals that neutralize acidic, potentially metal bearing, solutions and thus mitigate potential environmental effects of acid generation. Calibrated AVIRIS surface-reflectance data were spectrally analyzed to identify and map selected surface materials. Two maps were produced from each flightline of AVIRIS data: a map of iron-bearing minerals and water having absorption features in the spectral region from 0.35 ?m to 1.35 ?m and a map of minerals (including clays, sulfates, micas, and carbonates) having absorptions in the spectral region from 1.45 ?m to 2.51 ?m. Several methods were used to verify the AVIRIS mapping results, including field checking of selected locations with a portable spectrometer, visual inspection of the AVIRIS reflectance spectra, and X-ray diffraction (XRD) analysis of field samples. The maps of iron-bearing minerals derived from analysis of the visible (VIS) and near-infrared (NIR) regions of the electromagnetic spectrum were shown to be more consistently reliable in indicating the presence of jarosite than were the maps generated from analysis of the short-wave infrared (SWIR) region. When present in abundance, phyllosilicate minerals tend to dominate the SWIR and mask the spectral features of jarosite in that wavelength region. The crystal field absorptions of jarosite in the VIS and NIR spectral regions will commonly be present regardless of whether the Fe-OH absorption feature near 2.27 ?m can be detected. For this reason, the VIS and NIR were preferable to the SWIR for the remote spectroscopic identification of jarosite (and other iron-bearing minerals). Large exposures of unmined hydrothermally altered rocks occur throughout the three study areas. These rocks commonly contain sulfide or sulfate minerals that produce sulfuric acid upon subaerial oxidation. The acid may be introduced into local surface and ground water and thus lower the baseline (that is, the premining) pH for a watershed. The three study areas also have widespread exposures of rocks with acid-neutralizing potential. Lithologies containing carbonates and (or) other acid-buffering minerals-such as sedimentary limestones and dolomites and propylitically altered igneous rocks-were mapped with the AVIRIS data throughout the Oquirrh and East Tintic Mountains and locally in the Antelope Range and Tushar Mountains. Because elevated levels o

Well bore breakouts and in situ stress

USGS Publications Warehouse

Zoback, Mark D.; Moos, Daniel; Mastin, Larry; Anderson, Roger N.

1985-01-01

The detailed cross-sectional shape of stress induced well bore breakouts has been studied using specially processed ultrasonic borehole televiewer data. Breakout shapes are shown for a variety of rock types and introduce a simple elastic failure model which explains many features of the observations. Both the observations and calculations indicate that the breakouts define relatively broad and flat curvilinear surfaces which enlarge the borehole in the direction of minimum horizontal compression. Refs.

Fe-Ti-Cr-Oxides in Martian Meteorite EETA79001 Studied by Point-counting Procedure Using Raman Spectroscopy

NASA Technical Reports Server (NTRS)

Wang, Alian; Kuebler, Karla E.; Jolliff, Bradley L.; Haskin, Larry A.

2003-01-01

Fe-Ti-Cr-Oxide minerals contain much information about rock petrogenesis and alteration. Among the most important in the petrology of common intrusive and extrusive rocks are those of the FeO-TiO2-Cr2O3 compositional system chromite, ulv spinel-magnetite, and ilmenite-hematite. These minerals retain memories of oxygen fugacity. Their exsolution into companion mineral pairs give constraints on formation temperature and cooling rate. Laser Raman spectroscopy is anticipated to be a powerful technique for characterization of materials on the surface of Mars. A Mars Microbeam Raman Spectrometer (MMRS) is under development. It combines a micro sized laser beam and an automatic point-counting mechanism, and so can detect minor minerals or weak Raman-scattering phases such as Fe- Ti-Cr-oxides in mixtures (rocks & soils), and provide information on grain size and mineral mode. Most Fe-Ti-Cr-oxides produce weaker Raman signals than those from oxyanionic minerals, e.g. carbonates, sulfates, phosphates, and silicates, partly because most of them are intrinsically weaker Raman scatters, and partly because their dark colors limit the penetration depth of the excitation laser beam (visible wavelength) and of the Raman radiation produced. The purpose of this study is to show how well the Fe-Ti-Cr-oxides can be characterized by on-surface planetary exploration using Raman spectroscopy. We studied the basic Raman features of common examples of these minerals using well-characterized individual mineral grains. The knowledge gained was then used to study the Fe-Ti-Cr-oxides in Martian meteorite EETA79001, especially effects of compositional and structural variations on their Raman features.

The Rock Elm meteorite impact structure, Wisconsin: Geology and shock-metamorphic effects in quartz

USGS Publications Warehouse

French, B.M.; Cordua, W.S.; Plescia, J.B.

2004-01-01

The Rock Elm structure in southwest Wisconsin is an anomalous circular area of highly deformed rocks, ???6.5 km in diameter, located in a region of virtually horizontal undeformed sedimentary rocks. Shock-produced planar microstructures (PMs) have been identified in quartz grains in several lithologies associated with the structure: sandstones, quartzite pebbles, and breccia. Two distinct types of PMs are present: P1 features, which appear identical to planar fractures (PFs or cleavage), and P2 features, which are interpreted as possible incipient planar deformation features (PDFs). The latter are uniquely produced by the shock waves associated with meteorite impact events. Both types of PMs are oriented parallel to specific crystallographic planes in the quartz, most commonly to c(0001), ??112??2, and r/z101??1. The association of unusual, structurally deformed strata with distinct shock-produced microdeformation features in their quartz-bearing rocks establishes Rock Elm as a meteorite impact structure and supports the view that the presence of multiple parallel cleavages in quartz may be used independently as a criterion for meteorite impact. Preliminary paleontological studies indicate a minimum age of Middle Ordovician for the Rock Elm structure. A similar age estimate (450-400 Ma) is obtained independently by combining the results of studies of the general morphology of complex impact structures with estimated rates of sedimentation for the region. Such methods may be applicable to dating other old and deeply eroded impact structures formed in sedimentary target rocks.

Role of plant-rock interactions in the N cycle of oligotrophic environments

NASA Astrophysics Data System (ADS)

Gaddis, E. E.; Zaharescu, D. G.; Dontsova, K.; Chorover, J.; Galey, M.; Huxman, T. E.

2013-12-01

The vital role of nitrogen--an abundant, but inaccessible building block for growth--in plants is well known. At the same time, plants and microorganisms are driving forces for accumulation of available N in the soils as they form. A deep understanding of N cycle initiation, progression, and link to ecological systems and their development is therefore necessary. A mesocosm experiment was set up with the goal of exploring the role of interactions between four rock types and biota on N fate in oligotrophic environments. Basalt, rhyolite, granite, and schist were used with 6 treatments: abiotic control; microbes only; grass and microbes; pine and microbes; grass, microbes, and mycorrhizal fungi; and pine, microbes, and mycorrhizal fungi. Pinus ponderosa and Buchloe dactyloides were seeded on the different rock media and maintained with purified air and water but no nutrient additions for 8 month. Throughout the experiment leachate solution was collected and its chemical composition characterized, including organic and inorganic C and N. In addition, plant roots were scanned and their images analyzed to quantify their morphological features. Root parameters included measurements of length, surface area, diameter, volume, the number of tips, forks and links, altitude, and overall plant biomass. Over the 8 month period, there was sustained vegetation growth on all rocks without N addition. A high C:N ratio was seen across all substrates, indicating N deficiency. A strong relationship was observed between total N removal in soil leachate and a number of plant parameters, including plant biomass, total surface area of the roots, sum of the root tips, and total root volume. These relationships were the strongest in basalt, where the pines had higher root surface area than grasses and this was accompanied by higher total N in leachate. There was also a positive correlation between total N removal and the total biomass, total N and the sum of the root tips, and total N and the sum of the root volume. This work shows the strong root-rock interactions effect on N that is characteristic of oligotrophic environments. Significant differences in total N between rock types

Rock glaciers and related periglacial landforms in the Sierra Nevada, CA, USA; inventory, distribution and climatic relationships

Treesearch

Constance I. Millar; Robert D. Westfall

2008-01-01

Rock glaciers and related periglacial rock-ice features (RIFs) are abundant yet overlooked landforms in the Sierra Nevada, California, where they occur in diverse forms. We mapped 421 RIFs from field surveys, and grouped these into six classes based on morphology and location. These categories comprise a greater range of frozen-ground features than are commonly...

Assessing Heavy and Trace Metal Contamination in Surface Materials near the Ambaji and Zawar mines in Gujurat and Rajasthan, India using Airborne Visible/Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG) Data

NASA Astrophysics Data System (ADS)

Farrand, W. H.

2017-12-01

An investigation has begun into effects on water quality in waters coming from a pair of mines, and their surrounding drainage basins, in western India. The study areas are the Ambaji and Zawar mines in the Indian states of, respectively, Gujurat and Rajasthan. The Ambaji mine is situated in Precambrian-aged metasediments and metavolcanics of the Delhi Supergroup. Sulfide mineralization at Ambaji is hosted by hydrothermally altered felsic metavolcanics rocks with ferric oxide and oxyhydroxide as well as copper carbonate surface indicator minerals. The Zawar zinc mine is part of the Precambrian Aravalli Supergroup and lies amidst surface exposures of dolomites and quartzites. Hyperspectral visible through short-wave infrared (VSWIR) data from the Airborne Visible/Infrared Imaging Spectrometer Next Generation (AVIRIS-NG) was collected in February 2016 over these sites as part of a joint campaign between NASA and the Indian Space Research Organization (ISRO). The AVIRIS-NG data is being used to detect, map, and characterize surface mineralogy in the area. Data discovery is being carried out using a self-organizing map (SOM) methodology with mineral endmembers being mapped initially with a support vector machine (SVM) classifier and a planned more comprehensive mapping using the USGS Material Identification and Characterization Algorithm (MICA). Results of the mineral mapping will be field checked and rock, soil, and water samples will be collected and examined for heavy and trace metal contamination. Past studies have shown changes in the shape of the 2.2 mm Al-OH vibrational overtone feature as well as in blue-red spectral ratios that were directly correlated with the concentration of heavy and trace metals that had been adsorbed into the structure of the affected minerals. Early analysis of the Zawar area scenes indicates the presence of Al-OH clay minerals which might have been affected by the adsorption of trace metals. Scenes from the Ambaji area have more extensive surface exposures of carbonate minerals. Future work will focus more closely on detailed spectral feature mapping of absorption features that have been affected by heavy and trace metal adsorption.

Estimation of Mars radar backscatter from measured surface rock populations

USGS Publications Warehouse

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

1998-01-01

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

Helium Ion Microscopy: A Promising Tool for Probing Biota-Mineral Interfaces

NASA Astrophysics Data System (ADS)

Lybrand, R.; Zaharescu, D. G.; Gallery, R. E.

2017-12-01

The study of biogeochemical interfaces in soil requires powerful technologies that can enhance our ability to characterize mineral surfaces and interacting organisms at micro- to nanoscale resolutions. We aim to demonstrate potential applications of Helium Ion Microscopy in the earth and ecological sciences using, as an example, samples from a field experiment. We assessed samples deployed for one year along climatic and topographic gradients in two Critical Zone Observatories (CZOs): a desert to mixed conifer forest gradient (Catalina CZO) and a humid hardwood forest (Calhoun CZO). Sterile ground rock (basalt, quartz, and granite; 53-250 µm) was sealed into nylon mesh bags and buried in the surface soils of both CZOs. We employed helium ion and scanning electron microscopies to compare retrieved ground rock samples with sterile unreacted mineral controls in conjunction with the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory, USA. Our work showed early colonization of mesh bag materials by fungal and bacterial organisms from the field systems and identified morphological changes in mineral grains following exposure to the soil environment. Biological specimens observed on grain surfaces exhibited contrasting features depending on mineral type and ecosystem location, including fungal hyphae that varied in length, diameter, and surface morphologies. We also present imagery that provides evidence for incipient stages of mineral transformation at the fungal-mineral interface. Our findings demonstrate that helium ion microscopy can be successfully used to characterize grain features and biological agents of weathering in experimental field samples, representing a promising avenue for research in the biogeosciences. Future directions of this work will couple high resolution imaging with measures of aqueous and solid geochemistry, fungal morphological characterization, and microbial profiling to better understand mineral transformation along gradients of climate and topography.

Space Weathering of Rocks

NASA Technical Reports Server (NTRS)

Noble, Sarah

2011-01-01

Space weathering discussions have generally centered around soils but exposed rocks will also incur the effects of weathering. On the Moon, rocks make up only a very small percentage of the exposed surface and areas where rocks are exposed, like central peaks, are often among the least space weathered regions we find in remote sensing data. However, our studies of weathered Ap 17 rocks 76015 and 76237 show that significant amounts of weathering products can build up on rock surfaces. Because rocks have much longer surface lifetimes than an individual soil grain, and thus record a longer history of exposure, we can study these products to gain a deeper perspective on the weathering process and better assess the relative impo!1ance of various weathering components on the Moon. In contrast to the lunar case, on small asteroids, like Itokowa, rocks make up a large fraction of the exposed surface. Results from the Hayabusa spacecraft at Itokowa suggest that while the low gravity does not allow for the development of a mature regolith, weathering patinas can and do develop on rock surfaces, in fact, the rocky surfaces were seen to be darker and appear spectrally more weathered than regions with finer materials. To explore how weathering of asteroidal rocks may differ from lunar, a set of ordinary chondrite meteorites (H, L, and LL) which have been subjected to artificial space weathering by nanopulse laser were examined by TEM. NpFe(sup 0) bearing glasses were ubiquitous in both the naturally-weathered lunar and the artificially-weathered meteorite samples.

Alteration of Lunar Rock Surfaces through Interaction with the Space Environment

NASA Technical Reports Server (NTRS)

Frushour, A. M.; Noble, S. K; Christoffersen, R.; Keller, L P.

2014-01-01

Space weathering occurs on all ex-posed surfaces of lunar rocks, as well as on the surfaces of smaller grains in the lunar regolith. Space weather-ing alters these exposed surfaces primarily through the action of solar wind ions and micrometeorite impact processes. On lunar rocks specifically, the alteration products produced by space weathering form surface coatings known as patina. Patinas can have spectral reflectance properties different than the underlying rock. An understanding of patina composition and thickness is therefore important for interpreting re-motely sensed data from airless solar system bodies. The purpose of this study is to try to understand the physical and chemical properties of patina by expanding the number of patinas known and characterized in the lunar rock sample collection.

Space environment and lunar surface processes

NASA Technical Reports Server (NTRS)

Comstock, G. M.

1979-01-01

The development of a general rock/soil model capable of simulating in a self consistent manner the mechanical and exposure history of an assemblage of solid and loose material from submicron to planetary size scales, applicable to lunar and other space exposed planetary surfaces is discussed. The model was incorporated into a computer code called MESS.2 (model for the evolution of space exposed surfaces). MESS.2, which represents a considerable increase in sophistication and scope over previous soil and rock surface models, is described. The capabilities of previous models for near surface soil and rock surfaces are compared with the rock/soil model, MESS.2.

Snowmelt discharge characteristics Sierra Nevada, California

USGS Publications Warehouse

Peterson, David; Smith, Richard; Stewart, Iris; Knowles, Noah; Soulard, Chris; Hager, Stephen

2005-01-01

Alpine snow is an important water resource in California and the western U.S. Three major features of alpine snowmelt are the spring pulse (the first surge in snowmelt-driven river discharge in spring), maximum snowmelt discharge, and base flow (low river discharge supported by groundwater in fall). A long term data set of hydrologic measurements at 24 gage locations in 20 watersheds in the Sierra Nevada was investigated to relate patterns of snowmelt with stream discharge In wet years, the daily variations in snowmelt discharge at all the gage locations in the Sierra Nevada correlate strongly with the centrally located Merced River at Happy Isles, Yosemite National Park (i.e., in 1983, the mean of the 23 correlations was R= 0.93 + 0.09) ; in dry years, however, this correlation breaks down (i.e., in year 1977, R=0.72 + 0.24). A general trend towards earlier snowmelt was found and modeled using correlations with the timing of the spring pulse and the river discharge center of mass. For the 24 river and creek gage locations in this study, the spring pulse appeared to be a more sensitive measure of early snowmelt than the center of mass. The amplitude of maximum daily snowmelt discharge correlates strongly with initial snow water equivalent. Geologic factors, base rock permeability and soil-to-bedrock ratio, influence snowmelt flow pathways. Although both surface and ground water flows and water levels increase in wet years compared to dry years, the increase was greater for surface water in a watershed with relatively impermeable base rock than for surface water in a watershed with highly permeable base rock The relation was the opposite for base flow (ground water). The increase was greater for groundwater in a watershed with permeable rock compared to ground water in a watershed with impermeable rock. A similar, but weaker, surface/groundwater partitioning was observed in relatively impermeable granitic watersheds with differing soil-to-bedrock ratios. The increase in surface flow was greater in a watershed with a low, compared to a high, soil-to-bedrock ratio; whereas the increase in ground water flow was greater in a watershed with a high, compared to a low, soil-to-bedrock ratio. Transects that include long-term observations of shallow well-water depth and chemistry would complement traditional hydroclimate data and provide a more complete understanding of hydrologic controls of snowmelt.

Rock surface roughness measurement using CSI technique and analysis of surface characterization by qualitative and quantitative results

NASA Astrophysics Data System (ADS)

Mukhtar, Husneni; Montgomery, Paul; Gianto; Susanto, K.

2016-01-01

In order to develop image processing that is widely used in geo-processing and analysis, we introduce an alternative technique for the characterization of rock samples. The technique that we have used for characterizing inhomogeneous surfaces is based on Coherence Scanning Interferometry (CSI). An optical probe is first used to scan over the depth of the surface roughness of the sample. Then, to analyse the measured fringe data, we use the Five Sample Adaptive method to obtain quantitative results of the surface shape. To analyse the surface roughness parameters, Hmm and Rq, a new window resizing analysis technique is employed. The results of the morphology and surface roughness analysis show micron and nano-scale information which is characteristic of each rock type and its history. These could be used for mineral identification and studies in rock movement on different surfaces. Image processing is thus used to define the physical parameters of the rock surface.

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

The main mystery on Racetrack Playa is how the rocks move, but another, possibly greater mystery, is why some trails don't have rocks. Photo credit: NASA/GSFC/Mindy Krzykowski/LPSA intern To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Surface Signatures of an Underground Explosion as Captured by Photogrammetry

NASA Astrophysics Data System (ADS)

Schultz-Fellenz, E. S.; Sussman, A. J.; Swanson, E.; Coppersmith, R.; Cooley, J.; Rougier, E.; Larmat, C. S.; Norskog, K.

2016-12-01

This study employed high-resolution photogrammetric modeling to quantify cm-scale surface topographic changes resulting from a 5000kg underground chemical explosion. The test occurred in April 2016 at a depth of 76m within a quartz monzonite intrusion in southern Nevada. The field area was a 210m x 150m polygon broadly centered on the explosion's emplacement hole. A grid of ground control points (GCPs) installed in the field area established control within the collection boundaries and ensured high-resolution digital model parameterization. Using RTK GPS techniques, GCP targets were surveyed in the days before and then again immediately after the underground explosion. A quadcopter UAS with a 12MP camera payload captured overlapping imagery at two flight altitudes (10m and 30m AGL) along automated flight courses for consistency and repeatability. The overlapping imagery was used to generate two digital elevation models, pre-shot and post-shot, for each of the flight altitudes. Spatial analyses of the DEMs and orthoimagery show uplift on the order of 1 to 18cm in the immediate area near ground zero. Other features such as alluvial fracturing appear in the photogrammetric and topographic datasets. Portions of the nearby granite outcrop experienced rock fall and rock rotation. The study detected erosional and depositional features on the test bed and adjacent to it. In addition to vertical change, pre-shot and post-shot surveys of the GCPs suggest evidence for lateral motion on the test bed surface, with movement away from surface ground zero on the order of 1 to 3cm. Results demonstrate that UAS photogrammetry method provides an efficient, high-fidelity, non-invasive method to quantify surface deformation. The photogrammetry data allow quantification of permanent surface deformation and of the spatial extent of damage. These constraints are necessary to develop hydrodynamic and seismic models of explosions that can be verified against recorded seismic data.

Curiosity Checks Under the Dust on a Martian Rock

NASA Image and Video Library

2017-11-01

On a part of "Vera Rubin Ridge" where rover-team researchers sought to determine whether dust coatings are hiding rocks' hematite content, the Mast Camera (Mastcam) on NASA's Curiosity Mars rover took this image of a rock surface that had been brushed with the rover's Dust Removal Tool. The image is shown in the usual full color of featured Mastcam images: with a color adjustment similar to white balancing for approximating how the rocks and sand would appear under daytime lighting conditions on Earth. Sunlight on Mars is tinged by the dusty atmosphere and this adjustment helps geologists recognize color patterns they are familiar with on Earth. In this case, the purplish tint of the brushed area suggested fine-grained hematite. Bright lines within the rocks are fractures filled with calcium sulfate minerals. The brushed area is about 2.5 inches (6 centimeters) across. The image was taken on Sept. 17, 2017, during the 1,819th Martian day, or sol, of Curiosity's work on Mars. Mastcam also imaged this same scene using three special filters that help to identify hematite, an iron-oxide mineral that can provide information about ancient environmental conditions. A science-filters image identifies hematite in this brushed target even more clearly. https://photojournal.jpl.nasa.gov/catalog/PIA22067

Basic features of waste material storage in underground space in relation to geomechanics

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

Konecny, P.

1994-12-31

It is logical to consider utilizing underground cavities for waste material disposal because, during mining, great volumes of rock materials are extracted, and underground hollow areas and communicating workings are created that can, in general, be utilized for waste disposal. Additionally, in many cases, underground waste disposal favorably supports mining process technology (for instance, application of power plant fly ash and preparation plant tailings as hardened backfill). However, it is necessary to give particular attention to the preparation, operation, and isolation of underground tip areas; errors and, in extreme cases, emergencies in underground tips are generally more difficult to dealmore » with than those in surface tips. A tip place constructed underground becomes part of the rock massif; therefore, all natural laws that rule the rock massif must be respected. Of course, such an approach requires knowledge of processes and natural regularities that will occur in rock strata where tip places have been constructed. Such knowledge is gained through familiarity with contemporary geomechanical science. The paper discusses basic geomechanical principles of underground waste disposal; geomechanical aspects of rock massif evaluation in view of waste material storage in mine workings; and plans for an experimental project for waste disposal in the Dul Ostrava underground mine.« less

Potentiometric surface of the Upper Floridan aquifer in the Ichetucknee springshed and vicinity, northern Florida, September 2003

USGS Publications Warehouse

Sepulveda, A. Alejandro; Katz, Brian G.; Mahon, Gary L.

2006-01-01

The Upper Floridan aquifer is a highly permeable unit of carbonate rock extending beneath most of Florida and parts of southern Alabama, Georgia, and South Carolina. The high permeability is due in a large part to the widening of fractures that developed over time and the formation of conduits within the aquifer through dissolution of the limestone. This process has also produced numerous karst features such as springs, sinking streams, and sinkholes in northern Florida. These dissolution features, whether expressed at the surface or not, greatly influence the direction of ground-water flow in the Ichetucknee springshed adjacent to the Ichetucknee River. Ground water generally flows southwestward in the springshed and discharges to the Ichetucknee or Santa Fe Rivers, or to the springs along those rivers. This map depicts the September 9-10, 2003, potentiometric surface of the Upper Floridan aquifer based on 94 water-level measurements made by the Suwannee River Water Management District. Ground-water levels in this watershed fluctuate in response to precipitation and due to the high degree of interconnection between the surface-water system and the aquifer.

Role of lichens in weathering of granodiorite in the Sila uplands (Calabria, southern Italy)

NASA Astrophysics Data System (ADS)

Scarciglia, Fabio; Saporito, Natalina; La Russa, Mauro F.; Le Pera, Emilia; Macchione, Maria; Puntillo, Domenico; Crisci, Gino M.; Pezzino, Antonino

2012-12-01

This paper explores the role of five recurrent epilithic lichen species (Aspicilia intermutans (Nyl.) Arnold, Xanthoparmelia pulla (Ach.) O. Blanco, A. Crespo, Elix, D. Hawksw. & Lumbsch, Rhizocarpon lecanorinum Anders, Tephromela atra (Huds.) Hafellner and Lecanora bolcana (Pollini) Poelt), which encrust granodiorite spheroidal boulders exposed in the Sila uplands (Calabria, southern Italy), in weathering of plutonic rocks in a typical mountainous Mediterranean environment. A detailed investigation was carried out on the lichen-rock interface of each species, by comparing them mutually and with lichen-free granodiorite samples. For this purpose, the lichen species were sampled together with the encrusted rock surface for detailed mineral-petrographic analyses performed in thin and ultra-thin sections. Optical and scanning electron microscopy of these sections and of bulk samples permitted us to highlight the peculiar modes of physical and chemical attacks of lichen thalli and hyphae on and into the substratum for each species. Crack systems often parallel to the outer rock surface appear often intruded by hyphae, which cause rupture of primary minerals, with detachment and progressive incorporation of their fragments into the thallus. In particular, the species L. bolcana and T. atra revealed an unexpected, partly endolithic behavior, presumably enhanced by the presence of rock fractures earlier generated by other physical breakage processes already affecting the spheroidal boulders in the Sila mountains. Dissolution features often affect primary minerals (even quartz), that may show very peculiar patterns which are suggestive of a biologically-induced control. Various phyllosilicate clay minerals were identified using SEM-EDS microprobe analyses and FT-IR spectroscopy, which also enabled the identification of possible amorphous silica (or quartz micrograins), rhizocarpic acid and carotenoid at the encrusted granodiorite interface. In contrast, neither oxalic acids nor oxalates were detected.

Generalized surficial geologic map of the Fort Irwin area, San Bernadino: Chapter B in Geology and geophysics applied to groundwater hydrology at Fort Irwin, California

USGS Publications Warehouse

Miller, David M.; Menges, Christopher M.; Lidke, David J.; Buesch, David C.

2014-01-01

The geology and landscape of the Fort Irwin area, typical of many parts of the Mojave Desert, consist of rugged mountains separated by broad alluviated valleys that form the main coarse-resolution features of the geologic map. Crystalline and sedimentary rocks, Mesozoic and older in age, form most of the mountains with lesser accumulations of Miocene sedimentary and volcanic rocks. In detail, the area exhibits a fairly complex distribution of surficial deposits resulting from diverse rock sources and geomorphology that has been driven by topographic changes caused by recent and active faulting. Depositional environments span those typical of the Mojave Desert: alluvial fans on broad piedmonts, major intermittent streams along valley floors, eolian sand dunes and sheets, and playas in closed valleys that lack through-going washes. Erosional environments include rocky mountains, smooth gently sloping pediments, and badlands in readily eroded sediment. All parts of the landscape, from regional distribution of mountains, valleys, and faults to details of degree of soil development in surface materials, are portrayed by the surficial geologic map. Many of these attributes govern infiltration and recharge, and the surface distribution of permeable rock units such as Miocene sedimentary and volcanic rocks provides a basis for evaluating potential groundwater storage. Quaternary faults are widespread in the Fort Irwin area and include sinistral, east-striking faults that characterize the central swath of the area and the contrasting dextral, northwest-striking faults that border the east and west margins. Bedrock distribution and thickness of valley-fill deposits are controlled by modern and past faulting, and faults on the map help to identify targets for groundwater exploration.

Sedimentary Processes on Earth, Mars, Titan, and Venus

NASA Astrophysics Data System (ADS)

Grotzinger, J. P.; Hayes, A. G.; Lamb, M. P.; McLennan, S. M.

The production, transport and deposition of sediment occur to varying degrees on Earth, Mars, Venus, and Titan. These sedimentary processes are significantly influenced by climate that affects production of sediment in source regions (weathering), and the mode by which that sediment is transported (wind vs. water). Other, more geological, factors determine where sediments are deposited (topography and tectonics). Fluvial and marine processes dominate Earth both today and in its geologic past, aeolian processes dominate modern Mars although in its past fluvial processes also were important, Venus knows only aeolian processes, and Titan shows evidence of both fluvial and aeolian processes. Earth and Mars also feature vast deposits of sedimentary rocks, spanning billions of years of planetary history. These ancient rocks preserve the long-term record of the evolution of surface environments, including variations in climate state. On Mars, sedimentary rocks record the transition from wetter, neutral-pH weathering, to brine-dominated low-pH weathering, to its dry current state.

Meteorite Impact "Earthquake" Features (Rock Liquefaction, Surface Wave Deformations, Seismites) from Ground Penetrating Radar (GPR) and Geoelectric Complex Resistivity/Induced Polarization (IP) Measurements, Chiemgau (Alpine Foreland, Southeast Germany)

NASA Astrophysics Data System (ADS)

Ernstson, K.; Poßekel, J.

2017-12-01

Densely spaced GPR and complex resistivity measurements on a 30,000 square meters site in a region of enigmatic sinkhole occurrences in unconsolidated Quaternary sediments have featured unexpected and highlighting results from both a meteorite impact research and an engineering geology point of view. The GPR measurements and a complex resistivity/IP electrical imaging revealed extended subrosion depressions related with a uniformly but in various degrees of intensity deformed loamy and gravelly ground down to at least 10 m depth. Two principle observations could be made from both the GPR high-resolution measurements and the more integrating resistivity and IP soundings with both petrophysical evidences in good complement. Subrosion can be shown to be the result of prominent sandy-gravelly intrusions and extrusions typical of rock liquefaction processes well known to occur during strong earthquakes. Funnel-shaped structures with diameters up to 25 m near the surface and reaching down to the floating ground water level at 10 m depth were measured. GPR radargrams could trace prominent gravelly-material transport bottom-up within the funnels. Seen in both GPR tomography and resistivity/IP sections more or less the whole investigated area is overprinted by wavy deformations of the unconsolidated sediments with wavelengths of the order of 5 - 10 m and amplitudes up to half a meter, likewise down to 10 m depth. Substantial earthquakes are not known in this region. Hence, the observed heavy underground disorder is considered the result of the prominent earthquake shattering that must have occurred during the Holocene (Bronze Age/Celtic era) Chiemgau meteorite impact event that produced a 60 km x 30 km sized crater strewn field directly hosting the investigated site. Depending on depth and size of floating aquifers local concentrations of rock liquefaction and seismic surface waves (probably LOVE waves) to produce the wavy deformations could develop, when the big disintegrated meteoroid (a loosely bound asteroid or a comet of roughly estimated 1 km size) hit the ground. The observations in the Chiemgau area emphasize that studied paleoliquefaction features and wavy deformations (e.g. seismites) need not necessarily have originated solely from paleoseismicity but can provide a recognizable regional impact signature.

Two-way feedback between biology and deep Earth processes

NASA Astrophysics Data System (ADS)

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

2012-12-01

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

Formulation of dynamical theory of X-ray diffraction for perfect crystals in the Laue case using the Riemann surface.

PubMed

Saka, Takashi

2016-05-01

The dynamical theory for perfect crystals in the Laue case was reformulated using the Riemann surface, as used in complex analysis. In the two-beam approximation, each branch of the dispersion surface is specified by one sheet of the Riemann surface. The characteristic features of the dispersion surface are analytically revealed using four parameters, which are the real and imaginary parts of two quantities specifying the degree of departure from the exact Bragg condition and the reflection strength. By representing these parameters on complex planes, these characteristics can be graphically depicted on the Riemann surface. In the conventional case, the absorption is small and the real part of the reflection strength is large, so the formulation is the same as the traditional analysis. However, when the real part of the reflection strength is small or zero, the two branches of the dispersion surface cross, and the dispersion relationship becomes similar to that of the Bragg case. This is because the geometrical relationships among the parameters are similar in both cases. The present analytical method is generally applicable, irrespective of the magnitudes of the parameters. Furthermore, the present method analytically revealed many characteristic features of the dispersion surface and will be quite instructive for further numerical calculations of rocking curves.

A Fresh Crater Drills to Tharsis Bedrock

NASA Technical Reports Server (NTRS)

2007-01-01

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) took this image of a newly formed impact crater in the Tharsis region of Mars at 1316 UTC (8:16 a.m. EST) on Jan. 13, 2007, near 17.0 degrees north latitude, 246.4 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 20 meters (66 feet) across. The region covered by the image is just over 10 kilometers (6 miles) wide at its narrowest point.

The Tharsis region is a high volcanic plateau that stands about 5 kilometers (3 miles) above the surrounding plains. The rocks forming Tharsis are younger than in most parts of mars, as evidenced by their low density of craters. The best estimate of their age is comparable to the age of Shergotty-class meteorites thought to originate from Mars. However, Tharsis is covered by a nearly unbroken, meters-thick layer of dust that has frustrated all attempts to measure its bedrock composition remotely, and to determine if it matches the composition of Shergotty-class meteorites.

The recent discovery of dark, newly formed impact craters on Mars has provided the CRISM team a chance, finally, to measure the rocks that make up Tharsis. Over the lifetime of the Mars Global Surveyor mission, its high-resolution Mars Orbiter Camera monitored the surface and documented the very recent formation of some two dozen small impact craters. Several of them are in Tharsis and pierce the plateau's dust blanket to expose bedrock. MRO's instruments have been trained on these 'drill holes' into Mars' volcanic crust, including the crater shown here.

The top image was constructed from three infrared wavelengths that usually highlight compositional variations. This image shows the impact crater, a ring of dark, excavated rock (inset), and a surrounding system of rays. Crater rays are common around young impact craters, and they form when ejected boulders reimpact the surface and stir up the local rock and soil. The colors are bland because the scene is dominated by dust except for the dark crater and the ejecta immediately surrounding it.

The bottom image is a spectral map constructed using measurements of the 544-color spectra that separate dust and rock. The bright, deep orange areas are undisturbed dust. The crater rays' chocolate color in this rendition shows that they are slightly darker, more packed-down soil that was exposed by reimpacting boulders. The bright green color immediately around the new crater (inset) is where mafic rock (rock rich in the iron- and magnesium-containing minerals pyroxene and olivine) have been exposed.

CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials -- leading to new understanding of the climate.

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

Development of protocol for determination of natural stone bioreceptivity

NASA Astrophysics Data System (ADS)

Mauko Pranjić, Alenka; Mulec, Janez; Mesojedec, Mojca; Zalar Serjun, Vesna; Mladenovič, Ana

2017-04-01

Biodeterioration of stone surfaces in modern structures and cultural heritage is a problem that does not only affect the aesthetic appearance of stone elements but also changes their functionality due to material degradation and has indirectly a significant influence on the economy. The term bioreceptivity describes a material's susceptibility for the population of living organisms (Guiliette, 1995). Methods for bioreceptivity determination are usually based on a quantification of a grown microbiological mass on an exposed stone surface which was artificially inoculated with a pioneer organism (Guillitte and Dreesen, 1995; Miller et al, 2012). In our study a protocol for bioreceptivity determination was implemented based on an image analysis of autofluorescing pioneer organisms on sample surfaces exposed in growth chamber under specific laboratory conditions. The method is primarily meant for assessing the direct influence of intrinsic features of a rock on the rock's sensitivity for organism growth. Bioreceptivity has been determined on fifteen frequently used commercial types of natural stone for construction purposes in Slovenia. Mineral composition was determined with the help of microscopy and x-ray diffraction. Inoculated were three autotrophic organisms: Chlorella vulgaris, Chroococcus minutus and Pseudococcomyxa sp. Due to the fastest growth and insensitivity, the most appropriate microorganism for the laboratory experiment of bioreceptivity proved to be Chlorella vulgaris. It was established that different natural stones have a different bioreceptivity which depends on their mineral composition, roughness and physical features, e.g. type of porosity. In case of dry surface samples, the soaking of the surface and the capillary-type pores have the greatest influence. On the other hand, results of biorecepivity analysis examinations of water saturated samples show the prevalence of other mechanisms where the influence of mineral composition of a rock and grain size is likely to be higher. Literature Guillitte, O. Bioreceptivity: a new concept for building ecology studies. Sci Total Environ 1995; 167: 215-220. Guillitte, O., Dreesen, R. Laboratory chamber studies and petrographical analysis as bioreceptivity assessment tools of building materials. Sci Total Environ 1995; 167: 365-374. Miller, A.Z., Sanmartin, P., Pereira-Pardo, L.,Dionisio, A., Saiz-jimenez, C., Macedo, M.F., Prieto, B. 2012, Bioreceptivity of building stones: A review. Science of The Total Enviroment, 426: 1-12. Acknwnoledgments This study was supported by the Slovenian Research Agency under the project L1-5453.

Clay at Nili Fossae

NASA Technical Reports Server (NTRS)

2006-01-01

This image of the Nili Fossae region of Mars was compiled from separate images taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and the High-Resolution Imaging Science Experiment (HiRISE), two instruments on NASA's Mars Reconnaissance Orbiter. The images were taken at 0730 UTC (2:30 a.m. EDT) on Oct. 4, 2006, near 20.4 degrees north latitude, 78.5 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36 to 3.92 micrometers, and shows features as small as 18 meters (60 feet) across. HiRISE's image was taken in three colors, but its much higher resolution shows features as small as 30 centimeters (1 foot) across.

CRISM's sister instrument on the Mars Express spacecraft, OMEGA, discovered that some of the most ancient regions of Mars are rich in clay minerals, formed when water altered the planet's volcanic rocks. From the OMEGA data it was unclear whether the clays formed at the surface during Mars' earliest history of if they formed at depth and were later exposed by impact craters or erosion of the overlying rocks. Clays are an indicator of wet, benign environments possibly suitable for biological processes, making Nili Fossae and comparable regions important targets for both CRISM and HiRISE.

In this visualization of the combined data from the two instruments, the CRISM data were used to calculate the strengths of spectral absorption bands due to minerals present in the scene. The two major minerals detected by the instrument are olivine, a mineral characteristic of primitive igneous rocks, and clay. Areas rich in olivine are shown in red, and minerals rich in clay are shown in green. The derived colors were then overlayed on the HiRISE image.

The area where the CRISM and HiRISE data overlap is shown at the upper left, and is about 5 kilometers (3 miles) across. The three boxes outlined in blue are enlarged to show how the different minerals in the scene match up with different landforms. In the image at the upper right, the small mesa -- a flat-topped hill -- at the center of the image is a remnant of an overlying rock layer that was eroded away. The greenish clay areas at the base of the hill were exposed by erosion of the overlying rock. The images at the upper right and lower left both show that the reddish-toned olivine occurs as sand dunes on top of the greenish clay deposits. The image at the lower right shows details of the clay-rich rock, including that they are extensively fractured into small, polygonal blocks just a few meters in size. Taken together, the CRISM and HiRISE data show that the clay-rich rocks are the oldest at the site, that they are exposed where overlying rock has been eroded away, and that the olivine is not part of the clay-rich rock. Rather it occurs in sand dunes blowing across the clay.

Many more images of Nili Fossae and other clay-rich areas will be taken over the next two years. They will be used to try to understand the earliest climate of Mars that is recorded in the planet's rocks.

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials o leading to new understanding of the climate.

NASA's Jet Propulsion Laboratory, a division of the Califonia Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor and built the spacecraft.

Database and online map service on unstable rock slopes in Norway - From data perpetuation to public information

NASA Astrophysics Data System (ADS)

Oppikofer, Thierry; Nordahl, Bobo; Bunkholt, Halvor; Nicolaisen, Magnus; Jarna, Alexandra; Iversen, Sverre; Hermanns, Reginald L.; Böhme, Martina; Yugsi Molina, Freddy X.

2015-11-01

The unstable rock slope database is developed and maintained by the Geological Survey of Norway as part of the systematic mapping of unstable rock slopes in Norway. This mapping aims to detect catastrophic rock slope failures before they occur. More than 250 unstable slopes with post-glacial deformation are detected up to now. The main aims of the unstable rock slope database are (1) to serve as a national archive for unstable rock slopes in Norway; (2) to serve for data collection and storage during field mapping; (3) to provide decision-makers with hazard zones and other necessary information on unstable rock slopes for land-use planning and mitigation; and (4) to inform the public through an online map service. The database is organized hierarchically with a main point for each unstable rock slope to which several feature classes and tables are linked. This main point feature class includes several general attributes of the unstable rock slopes, such as site name, general and geological descriptions, executed works, recommendations, technical parameters (volume, lithology, mechanism and others), displacement rates, possible consequences, as well as hazard and risk classification. Feature classes and tables linked to the main feature class include different scenarios of an unstable rock slope, field observation points, sampling points for dating, displacement measurement stations, lineaments, unstable areas, run-out areas, areas affected by secondary effects, along with tables for hazard and risk classification and URL links to further documentation and references. The database on unstable rock slopes in Norway will be publicly consultable through an online map service. Factsheets with key information on unstable rock slopes can be automatically generated and downloaded for each site. Areas of possible rock avalanche run-out and their secondary effects displayed in the online map service, along with hazard and risk assessments, will become important tools for land-use planning. The present database will further evolve in the coming years as the systematic mapping progresses and as available techniques and tools evolve.

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

NASA Technical Reports Server (NTRS)

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

1998-01-01

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

Climbing walls as multitasking sites of geo(morpho)logical interests: Italian examples from the Western Alps and Sardinia

NASA Astrophysics Data System (ADS)

Bollati, Irene; Fossati, Maria; Panizza, Valeria; Pelfini, Manuela; Zanoletti, Enrico; Zucali, Michele

2015-04-01

Geosites and in particular geomorphosites have been recently more and more used as base for educational activities in Earth Sciences and to enhance the geodiversity of a territory. Their attributes acquire a greater value and become especially appreciable when associated with field and outdoor activities. Frequently rock walls represent key sites for geological and gemorphological researches due to the wide outcrops of rocks where mineralogical composition and structures are very evident as well as landforms deriving from the modeling of outcrops surfaces. Where the rock walls are equipped for climbing activities they may be considered open-air laboratories useful to get in touch with the different features of rocks that condition progression on climbing routes. Due to these two aspects, geohistorical importance and educational exemplarity contribute to the increase of the scientific value and, as a consequence, of the global value of these sites as geosites. Geomorphosites from climbing sites allow to realize educational projects with different goals: 1) Recent researches in the Western Italian Alps have been conducted to make a census of climbing rock cliffs along the Ossola Valley (Verbanio-Cusio-Ossola Province, Italy) and to operate a choice of the ones characterized by high educational value (considering easy accessibility, grades for experts and beginners and the good exposition of rock features), representativeness, geohistorical importance, high cultural and socio-economic values, in order to propose an educational project addressed to students of an Italian secondary school aimed at introducing the three great families of rocks (magmatic, metamorphic and sedimentary); 2) The Eclogitic Micaschist Complex of the Austroalpine Domain (Montestrutto climbing wall, Turin Province, Italy) has been investigated in order to i) reconstruct the deformation stages at local scales along the sport climbing wall and the relationships between geological elements and physical elements necessary for vertical progression ii) elaborate an educational proposal; 3) Risk assessment and education has been approached through the analysis of site hazard on climbing routes, linked with both geomorphological processes, and to the variable meteorological conditions, at Monteleone Rocca Doria (Sardinia, Italy), a site sensitive to both the needs of the climbers and the environment. Here a particular attention was given to potential geomorphologically-related risks for climbers, the impacts linked to human presence and the specific features of the geomorphosite. In order to assess the possible risk situations related to the active geomorphological processes in a specific climbing site, a method for collecting data and information has been also proposed.

Final Environmental Assessment: Construction of SWMU 74 Groundwater Extraction and Convenience System Arnold Air Force Base, Tennessee

DTIC Science & Technology

2004-08-01

winter when birds migrate from the north. Most of the birds congregate during the winter at Reelfoot Lake and Dale Hollow Reservoir, but bald eagles...streams (USDA Soil Conservation Service, 1949). 3.1.2 Hydrology Hydrological features include surface waters ( lakes , rivers, streams, and springs) and...Fahrenheit (Smith, 2004). Precipitation is fairly evenly distributed throughout the year, with slightly Woods Reservoir Normandy Lake Tims Ford LakeRock

Microbial mat records in siliciclastic rocks: Examples from Four Indian Proterozoic basins and their modern equivalents in Gulf of Cambay

NASA Astrophysics Data System (ADS)

Sarkar, Subir; Banerjee, Santanu; Samanta, Pradip; Chakraborty, Nivedita; Chakraborty, Partha Pratim; Mukhopadhyay, Soumik; Singh, Arvind K.

2014-09-01

Microbial mat-related structures (MRS) in siliciclastics have been investigated from four Proterozic formations in India, namely the Marwar Supergroup, the Vindhyan Supergroup, the Chhatisgarh Supergroup and the Khariar Group for their spectral variations, genetic aspects, palaeo-environmental significance and influence on sequence stratigraphic architecture. The maximum diversification of MRS has been experienced in shallow marine coastal Precambrian successions. Observations made from modern environment as well as Precambrian rock records clearly indicates that the features like petee ridges, sand-cracks, gas domes, multi-directed ripples, reticulate surfaces, sieve-like surfaces and setulf are most likely to form in the shallowest part of the marine basins, in upper intertidal to supratidal conditions while wrinkle structures, roll-up structures and patchy ripples had a broader range of palaeogeographic settings from the supratidal to subtidal conditions. Discoidal microbial colony (DMC) represents a special variety of the mat-layer feature in modern environment that may have diverse internal architecture, sometimes falsely resembles Ediacaran medusoids. The uniqueness in sequence stratigraphic architecture of the microbial mat-covered sediment is reflected by the presence of more amalgamated HSTs compare to that of TSTs. The preservation of forced and normal regressive deposits on low-gradient epeiric shelf under low continental freeboard indicates microbial mat-infested sea-floor impedes erosion and concomitant sediment supply may facilitate formation and preservation of regressive packages.

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

To investigate the rocks and trails, the interns collect many kinds of data, such as trail length, width, and depth; rock size; magnetic and radiation measurements; and GPS coordinates. The students also photograph the rocks, the trails and the cracks in the mud within and outside the trails. Photo credit: NASA/GSFC/Maggie McAdam To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

New Constraints on the Rock Size Distribution on the Moon from Diviner Infrared Measurements

NASA Astrophysics Data System (ADS)

Elder, C. M.; Hayne, P. O.; Piqueux, S.; Bandfield, J. L.; Ghent, R. R.; Williams, J. P.; Paige, D. A.

2015-12-01

Most of the Moon's surface is covered by fine-grained regolith produced by impacts, but rocks of various sizes are also present. Rock abundances can be used to distinguish different surface units and quantify the ages of craters [1,2]. Furthermore, the size distribution of a population of rocks reflects the process by which they were formed and fragmented [3]. Knowing the distribution of rock sizes on the Moon can improve our understanding of regolith generation, evolution, and distribution, can be used to select landing sites, and can provide insight into the processes that have shaped the lunar surface. The high thermal inertia of rocks compared to fine-grained regolith leads to multiple temperatures within the field of view of nighttime multispectral data returned from the Lunar Reconnaissance Orbiter (LRO) Diviner thermal radiometer. This data has been used to map the rock abundance across the lunar surface [1]. However, the derived rock abundance is not constant over the course of the lunar night; small rocks cool faster than large rocks and eventually become indistinguishable from regolith using Diviner data. Thus the detectable rock abundance will decrease over the course of the lunar night. Here we use this change in measured rock abundance with time to constrain the size distribution of rock fragments, and map its variation across the lunar surface. We will show results from this study and discuss the implications for the geologic processes shaping the lunar surface. [1] Bandfield J. L. et al. (2011) JGR, 116, E00H02. [2] Ghent R. R. et al. (2014) Geology, 42, no. 12, 1059-1062. [3] Hartmann W. K. (1969) Icarus, 10, 201-213. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration.

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

DOEpatents

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

2014-12-30

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

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.

Formative Processes of a Sliding Zone in Pelitic Schist - Implications of Microscopic Analyses on High-quality Drilled Cores

NASA Astrophysics Data System (ADS)

Yamasaki, S.; Chigira, M.

2009-04-01

Pelitic schist has been known to be easily deformed by gravitational force to form characteristic topographic and geologic features, but little is known about how they develop. This is mainly due to the fact that deformed politic schist is so fragile that it could not be obtained from subsurface without disturbance. We analyzed high-quality undisturbed cores obtained by using a sophisticated drilling technique from two typical pelitic schist landslide sites in Japan. We made analyses on physical, chemical, mineralogical properties and observations from mesoscopic to microscopic rock textures of these cores and found that a special layering of rock-forming minerals determines the locations of shearing by gravity and that there is specific water-rock interaction processes in pelitic schist. Pelitic schist consists of thinly alternating beds of black layers and quartz-rich layers, and a black layer has numerous microscopic layers containing abundant pyrite and graphite grains (pyrite-graphite layers). Many of the black layers were observed to have microfractures connected to open cracks, suggesting that relatively thick, continuous black layers are easily sheared to form an incipient sliding layer. Thus unevenly distributed pyrite-graphite layers likely to determine the potential location of microscopic slip in a rock mass. Shear displacement along black layers occurs unevenly, depending upon the microscopic heterogeneity in mineral composition as well as undulating shape of the layers. Open micro-cracks nearly perpendicular to the schistosity were commonly observed in quartz-rich layers in contact with black layers, suggesting that the shearing occurred with heterogeneous displacements along the black layer and that it occurred under the low confining pressure. This is in the incipient stage of a fracture zone. When shearing occurs along two thick neighboring black layers, the rock in between would be fractured, rotated and pulverized. In some cases, quartz-rich layers were fractured in a brittle manner and their fragments were rearranged to form micro-folds. Rocks are thus pulverized with multiple shear surfaces. Incipient fracture zones and their surroundings have many voids because they are made under low confining pressures near the ground surface, so oxidizing surface water easily percolates through them. Oxidizing water reacts with pyrite which is contained in pelitic schist, producing sulfuric acid through. The rocks therefore become deteriorated by the water-rock interaction and would be easily deformed. Such a combination of the physical processes of deformation and fracturing and the chemical process of weathering develop a sliding zone.

A Fairy-Tale Landscape

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on image for animation

Fun, fairy-tale nicknames have been assigned to features in this animated view of the workspace reachable by the robotic arm of NASA's Phoenix Mars Lander. For example, 'Sleepy Hollow' denotes a trench and 'Headless' designates a rock.

A 'National Park,' marked by purple text and a purple arrow, has been set aside for protection until scientists and engineers have tested the operation of the robotic scoop. First touches with the scoop will be to the left of the 'National Park' line.

Scientists use such informal names for easy identification of features of interest during the mission.

In this view, rocks are circled in yellow, other areas of interest in green. The images were taken by the lander's 7-foot mast camera, called the Surface Stereo Imager.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Thermal evolution of a differentiated Ganymede and implications for surface features

NASA Technical Reports Server (NTRS)

Kirk, R. L.; Stevenson, D. J.

1987-01-01

Thermodynamic models are developed for the processes which controlled the evolution of the surface Ganymede, an icy Jovian satellite assumed to have a rock-rich core surrounded by a water-ice mantle. Account is taken of a heat pulse which would have arisen from a Rayleigh-Taylor instability at a deep-seated liquid-solid water interface, rapid fracturing from global stresses imposed by warm ice diapiric upwelling, impacts by large meteorites, and resurfacing by ice flows (rather than core formation). Comparisons are made with existing models for the evolution of Callisto, and the difficulties in defining a mechanism which produced the groove terrain of Ganymede are discussed.

Database of historically documented springs and spring flow measurements in Texas

USGS Publications Warehouse

Heitmuller, Franklin T.; Reece, Brian D.

2003-01-01

Springs are naturally occurring features that convey excess ground water to the land surface; they represent a transition from ground water to surface water. Water issues through one opening, multiple openings, or numerous seeps in the rock or soil. The database of this report provides information about springs and spring flow in Texas including spring names, identification numbers, location, and, if available, water source and use. This database does not include every spring in Texas, but is limited to an aggregation of selected digital and hard-copy data of the U.S. Geological Survey (USGS), the Texas Water Development Board (TWDB), and Capitol Environmental Services.

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

NASA Astrophysics Data System (ADS)

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

2010-05-01

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

Saline Valley

NASA Image and Video Library

2001-10-22

These images of the Saline Valley area, California, were acquired March 30, 2000 and cover a full ASTER scene (60 by 60 km). Each image displays data from a different spectral region, and illustrates the complementary nature of surface compositional information available as a function of wavelength. This image displays visible and near infrared bands 3, 2, and 1 in red, green, and blue (RGB). Vegetation appears red, snow and dry salt lakes are white, and exposed rocks are brown, gray, yellow and blue. Rock colors mainly reflect the presence of iron minerals, and variations in albedo. Figure 1 displays short wavelength infrared bands 4, 6, and 8 as RGB. In this wavelength region, clay, carbonate, and sulfate minerals have diagnostic absorption features, resulting in distinct colors on the image. For example, limestones are yellow-green, and purple areas are kaolinite-rich. Figure 2 displays thermal infrared bands 13, 12 and 10 as RGB. In this wavelength region, variations in quartz content appear as more or less red; carbonate rocks are green, and mafic volcanic rocks are purple. The image is located at 36.8 degrees north latitude and 117.7 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA11164

Influence of dunite mineral additive on strength of cement

NASA Astrophysics Data System (ADS)

Vasilyeva, A. A.; Moskvitina, L. V.; Moskvitin, S. G.; Lebedev, M. P.; Fedorova, G. D.

2017-12-01

The work studies the applicability of dunite rocks from Inagli massif (South Yakutia) for the production of mixed (composite) cement. The paper reviews the implementation of dunite for manufacturing materials and products. The chemical and mineral compositions of Inagli massif dunite rocks are presented, which relegate the rocks to magnesia-silicate rocks of low-quality in terms of its application as refractory feedstock due to appreciable serpentinization of dunite. The work presents the results of dunite study in terms of its applicability as an additive to Portland cement. The authors have established that dunite does not feature hydraulicity and can be used as a filling additive to Portland cement in the amount of up to 40%. It was unveiled that the mixed grinding of Portland cement and dunite sand with specific surface area of 5500 cm2/g yields the cement that complies with GOST 31108-2016 for CEM II and CEM V normal-cured cements with strength grades of 32.5 and 42.5. The work demonstrates the benefits of the studies of dunite as a filling additive for producing both Portland cement with mineral component and composite (mixed) cement.

Earth Observations taken by Expedition 38 Crewmember

NASA Image and Video Library

2014-02-14

ISS038-E-047388 (14 Feb. 2014) --- As the International Space Station passed over the deserts of central Iran, including Kavir, one of the Expedition 38 crew members used a digital camera equipped with a 200mm lens to record this image featuring an unusual pattern of numerous parallel lines and sweeping curves. The lack of soil and vegetation allows the geological structure of the rocks to appear quite clearly. According to geologists, the patterns result from the gentle folding of numerous, thin, light and dark layers of rock. Later erosion by wind and water, say the scientists, cut a flat surface across the folds, not only exposing hundreds of layers but also showing the shapes of the folds. The dark water of a lake (image center) occupies a depression in a more easily eroded, S-shaped layer of rock. The irregular light-toned patch just left of the lake is a sand sheet thin enough to allow the underlying rock layers to be detected. A small river snakes across the bottom of the image. In this desert landscape there are no fields or roads to give a sense of scale. In fact, the image width represents a distance of 65 kilometers.

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

NASA Astrophysics Data System (ADS)

Funk, Daniel; Krautblatter, Michael

2010-05-01

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

The 'Razorback' Mystery

NASA Technical Reports Server (NTRS)

2004-01-01

The pointy features in this image may only be a few centimeters high and less than 1 centimeter (0.4 inches) wide, but they generate major scientific interest. Dubbed 'Razorback,' this chunk of rock sticks up at the edge of flat rocks in 'Endurance Crater.' Based on their understanding of processes on Earth, scientists believe these features may have formed when fluids migrated through fractures, depositing minerals. Fracture-filling minerals would have formed veins composed of a harder material that eroded more slowly than the rock slabs.

Possible examination of these features using the instruments on NASA's Mars Exploration Rover Opportunity may further explain what these features have to do with the history of water on Mars. This false-color image was taken by the rover's panoramic camera.

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

There's nothing special about these rocks, which are ordinary dolomite from the surrounding mountains. The rocks move because of where they are, not what they are made of. Credit: NASA/GSFC/Maggie McAdam To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Ramp Creek and Harrodsburg Limestones: A shoaling-upward sequence with storm-produced features in southern Indiana, U.S.A.. Carbonate petrology seminar, Indiana University

NASA Astrophysics Data System (ADS)

1987-05-01

Most previously described examples of storm-produced stratification have been reported from siliciclastic rocks. However, such features should also be common in carbonate rocks. The Mississippian (Valmeyeran) Ramp Creek and Harrodsburg Limestones, deposited on the east margin of the Illinois Basin on top of the Borden Delta, contain storm-produced features. The dolomitic, geode-bearing Ramp Creek Limestone contains muddying-upward sequences, commonly with scoured bases overlain by grainstones, packstones, wackestones, and burrowed mudstones. These sequences are similar to hummocky sequences formed by storm waves below fair-weather wave base. The middle portion of the section including the upper Ramp Creek and lower Harrodsburg Limestones contains dolomitized mud lenses of uncertain origin. They may have formed by the baffling effect of bryozoans and/or unpreserved algae. The Harrodsburg is gradational with the Ramp Creek and consists predominantly of grainstones and packstones deposited in shallower water. Low-angle cross-stratification and truncation surfaces suggest a foreshore depositional environment for the Harrodsburg. Neither formation contains any indication of supratidal deposition as has been previously suggested. Open marine conditions during deposition of both formations are indicated by the fauna which includes crinoids, bryozoans, brachiopods, corals, ostracods, echinoids, trilobites, molluscs, fish (sharks), and trace fossils.

Automatic rocks detection and classification on high resolution images of planetary surfaces

NASA Astrophysics Data System (ADS)

Aboudan, A.; Pacifici, A.; Murana, A.; Cannarsa, F.; Ori, G. G.; Dell'Arciprete, I.; Allemand, P.; Grandjean, P.; Portigliotti, S.; Marcer, A.; Lorenzoni, L.

2013-12-01

High-resolution images can be used to obtain rocks location and size on planetary surfaces. In particular rock size-frequency distribution is a key parameter to evaluate the surface roughness, to investigate the geologic processes that formed the surface and to assess the hazards related with spacecraft landing. The manual search for rocks on high-resolution images (even for small areas) can be a very intensive work. An automatic or semi-automatic algorithm to identify rocks is mandatory to enable further processing as determining the rocks presence, size, height (by means of shadows) and spatial distribution over an area of interest. Accurate rocks and shadows contours localization are the key steps for rock detection. An approach to contour detection based on morphological operators and statistical thresholding is presented in this work. The identified contours are then fitted using a proper geometric model of the rocks or shadows and used to estimate salient rocks parameters (position, size, area, height). The performances of this approach have been evaluated both on images of Martian analogue area of Morocco desert and on HiRISE images. Results have been compared with ground truth obtained by means of manual rock mapping and proved the effectiveness of the algorithm. The rock abundance and rocks size-frequency distribution derived on selected HiRISE images have been compared with the results of similar analyses performed for the landing site certification of Mars landers (Viking, Pathfinder, MER, MSL) and with the available thermal data from IRTM and TES.

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

Zhang, Hanlei; May, Brian M.; Serrano-Sevillano, Jon

The surface configuration of pristine layered oxide cathode particles for Li-ion batteries significantly affects the electrochemical behavior, which is generally considered to be a thin rock-salt layer in the surface. Unfortunately, aside from its thin nature and spatial location on the surface, the true structural nature of this surface rock-salt layer remains largely unknown, creating the need to understand its configuration and the underlying mechanisms of formation. Using scanning transmission electron microscopy, we have found a correlation between the surface rock-salt formation and the crystal facets on pristine LiNi0.80Co0.15Al0.05O2 primary particles. It is found that the originally (01more » $$ \\overline{4}\\ $$) and (003) surfaces of the layered phase result in two kinds of rock-salt reconstructions: the (002) and (111) rock-salt surfaces, respectively. Stepped surface configurations are generated for both reconstructions. The (002) configuration is relatively flat with monoatomic steps while the (111) configuration shows significant surface roughening. Both reconstructions reduce the ionic and electronic conductivity of the cathode, leading to a reduced electrochemical performance.« less

On the dual nature of lichen-induced rock surface weathering in contrasting micro-environments.

PubMed

Marques, Joana; Gonçalves, João; Oliveira, Cláudia; Favero-Longo, Sergio E; Paz-Bermúdez, Graciela; Almeida, Rubim; Prieto, Beatriz

2016-10-01

Contradictory evidence from biogeomorphological studies has increased the debate on the extent of lichen contribution to differential rock surface weathering in both natural and cultural settings. This study, undertaken in Côa Valley Archaeological Park, aimed at evaluating the effect of rock surface orientation on the weathering ability of dominant lichens. Hyphal penetration and oxalate formation at the lichen-rock interface were evaluated as proxies of physical and chemical weathering, respectively. A new protocol of pixel-based supervised image classification for the analysis of periodic acid-Schiff stained cross-sections of colonized schist revealed that hyphal spread of individual species was not influenced by surface orientation. However, hyphal spread was significantly higher in species dominant on northwest facing surfaces. An apparently opposite effect was noticed in terms of calcium oxalate accumulation at the lichen-rock interface; it was detected by Raman spectroscopy and complementary X-ray microdiffraction on southeast facing surfaces only. These results suggest that lichen-induced physical weathering may be most severe on northwest facing surfaces by means of an indirect effect of surface orientation on species abundance, and thus dependent on the species, whereas lichen-induced chemical weathering is apparently higher on southeast facing surfaces and dependent on micro-environmental conditions, giving only weak support to the hypothesis that lichens are responsible for the currently observed pattern of rock-art distribution in Côa Valley. Assumptions about the drivers of open-air rock-art distribution patterns elsewhere should also consider the micro-environmental controls of lichen-induced weathering, to avoid biased measures of lichen contribution to rock-art deterioration. © 2016 by the Ecological Society of America.

The surface of Mars: An unusual laboratory that preserves a record of catastrophic and unusual events

USGS Publications Warehouse

Chapman, M.G.

2009-01-01

Catastrophic and unusual events on Earth such as bolide impacts, megafloods, supereruptions, flood volcanism, and subice volcanism may have devastating effects when they occur. Although these processes have unique characteristics and form distinctive features and deposits, we have diffi culties identifying them and measuring the magnitude of their effects. Our diffi culties with interpreting these processes and identifying their consequences are understandable considering their infrequency on Earth, combined with the low preservation potential of their deposits in the terrestrial rock record. Although we know these events do happen, they are infrequent enough that the deposits are poorly preserved on the geologically active face of the Earth, where erosion, volcanism, and tectonism constantly change the surface. Unlike the Earth, on Mars catastrophic and unusual features are well preserved because of the slow modifi cation of the surface. Signifi cant precipitation has not occurred on Mars for billions of years and there appears to be no discrete crustal plates to have undergone subduction and destruction. Therefore the ancient surface of Mars preserves geologic features and deposits that result from these extraordinary events. Also, unlike the other planets, Mars is the most similar to our own, having an atmosphere, surface ice, volcanism, and evidence of onceflowing water. So although our understanding of precursors, processes, and possible biological effects of catastrophic and unusual processes is limited on Earth, some of these mysteries may be better understood through investigating the surface of Mars. ?? 2009 The Geological Society of America.

Quantitative lithologic mapping in spectral ratio feature space - Volcanic, sedimentary and metamorphic terrains

NASA Technical Reports Server (NTRS)

Campos-Marquetti, Raul, Jr.; Rockwell, Barnaby

1990-01-01

The nature of spectral lithologic mapping is studied utilizing ratios centered around the wavelength means of TM imagery. Laboratory-derived spectra are analyzed to determine the two-dimensional relationships and distributions visible in spectral ratio feature space. The spectral distributions of various rocks and minerals in ratio feature space are found to be controlled by several spectrally dominant molecules. Three study areas were examined: Rawhide Mining District, Nevada; Manzano Mountains, New Mexico; and the Sevilleta Long Term Ecological Research site in New Mexico. It is shown that, in the comparison of two ratio plots of laboratory reflectance spectra, i.e., 0.66/0.485 micron versus 1.65/2.22 microns with those derived from TM data, several molecules spectrally dominate the reflectance characteristic of surface lithologic units. Utilizing the above ratio combination, two areas are successfully mapped based on their distribution in spectral ratio feature space.

Fire effects on rock images and similar cultural resources [Chapter 5

Treesearch

Roger E. Kelly; Daniel F. McCarthy

2012-01-01

Throughout human global history, people have purposely altered natural rock surfaces by drilling, drawing, painting, incising, pecking, abrading and chiseling images into stone. Some rock types that present suitable media surfaces for these activities are fine-grained sandstones and granites, basalts, volcanic tuff, dolomites, and limestones. Commonly called rock...

The formation of technic soil in a revegetated uranium ore waste rock pile (Limousin, France)

NASA Astrophysics Data System (ADS)

Boekhout, Flora; Gérard, Martine; Kanzari, Aisha; Calas, Georges; Descostes, Michael

2014-05-01

Mining took place in France between 1945 and 2001 during which time ~210 different sites were exploited and/or explored. A total of 76 Kt of uranium was produced, 52 Mt of ore was extracted, but also 200 Mt of waste rocks was produced, the majority of which, with uranium levels corresponding to the natural environment. So far, the processes of arenisation and technic soil formation in waste rock piles are not well understood but have important implications for understanding the environmental impact and long-term speciation of uranium. Understanding weathering processes in waste rock piles is essential to determine their environmental impact. The main objectives of this work are to assess 1) the micromorphological features and neo-formed U-bearing phases related to weathering and 2) the processes behind arenisation of the rock pile. The site that was chosen is the Vieilles Sagnes waste rock pile in Fanay (Massif Central France) that represents more or less hydrothermally altered granitic rocks that have been exposed to weathering since the construction of the waste rock pile approximately 50 years ago. Two trenches were excavated to investigate the vertical differentiation of the rock pile. This site serves as a key location for studying weathering processes of waste rock piles, as it has not been reworked after initial construction and has therefore preserved information on the original mineralogy of the waste rock pile enabling us to access post emplacement weathering processes. The site is currently overgrown by moss, meter high ferns and small trees. At present day the rock pile material can be described as hydrothermally altered rocks and rock fragments within a fine-grained silty clay matrix exposed to surface conditions and weathering. A sandy "paleo" technic soil underlies the waste rock pile and functions as a natural liner by adsorption of uranium on clay minerals. Post-mining weathering of rock-pile material is superimposed on pre-mining hydrothermal and possible supergene alteration. Clay minerals present are kaolinite, smectite and chlorite. The formation of these minerals is however ambiguous, and can form during both hydrothermal as weathering processes, calling for a detailed micromorphological study. Micromorphological investigations on undisturbed samples by microscopic and ultramicroscopic techniques allow us to interpretate the processes behind the formation of technic soil in the matrix of the waste rock pile, as well as the rate and chronology of mineral formation and arenisation related to weathering (formation of protosoil and saprolitisation). By studying the formation of weathering aureaoles in between the different granitic blocks, we quantify the anthropogenic influence on weathering of this rock pile and their impacts on local ecosystem by comparing our site with natural occuring outcrops of granites currently subjected to weathering. Electron microscope imaging and microgeochemical mapping permits us to make detailed micromorphological observations linking nanoscale processes to petrolographical macroscopic features and field observations. Different petrographic and electronic images of the mineral paragenesis in the micromass associated to their microgeochemical characteristics will be presented. Also, the impact of previous hydrothermal alteration will be highlighted.

Geology and impact features of Vargeão Dome, southern Brazil

NASA Astrophysics Data System (ADS)

Crósta, Alvaro P.; Kazzuo-Vieira, César; Pitarello, Lidia; Koeberl, Christian; Kenkmann, Thomas

2012-01-01

Vargeão Dome (southern Brazil) is a circular feature formed in lava flows of the Lower Cretaceous Serra Geral Formation and in sandstones of the Paraná Basin. Even though its impact origin was already proposed in the 1980s, little information about its geological and impact features is available in the literature. The structure has a rim-rim diameter of approximately 12 km and comprises several ring-like concentric features with multiple concentric lineaments. The presence of a central uplift is suggested by the occurrence of deformed sandstone strata of the Botucatu and Pirambóia formations. We present the morphological/structural characteristics of Vargeão Dome, characterize the different rock types that occur in its interior, mainly brecciated volcanic rocks (BVR) of the Serra Geral Formation, and discuss the deformation and shock features in the volcanic rocks and in sandstones. These features comprise shatter cones in sandstone and basalt, as well as planar microstructures in quartz. A geochemical comparison of the target rock equivalents from outside the structure with the shocked rocks from its interior shows that both the BVRs and the brecciated sandstone have a composition largely similar to that of the corresponding unshocked lithologies. No traces of meteoritic material have been found so far. The results confirm the impact origin of Vargeão Dome, making it one of the largest among the rare impact craters in basaltic targets known on Earth.

Brittle strength of basaltic rock masses with applications to Venus

NASA Astrophysics Data System (ADS)

Schultz, R. A.

1993-06-01

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

Northeast Arabia Terra

NASA Technical Reports Server (NTRS)

2004-01-01

9 September 2004 Northeastern Arabia Terra is a heavily eroded portion of the martian cratered highlands. Layered rock, containing filled and buried valleys and ancient impact craters, has been eroded such that these once-buried features are now partially exposed at the martian surface. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example of a field of circular and somewhat circular features that once were impact craters that were subsequently filled, buried, then exhumed to form the patterns exhibited here. The image is located near 25.6oN, 290.2oW. The image covers an area approximately 3 km (1.9 mi) across and is illuminated by sunlight from the lower left.

Aeolian Abrasion at the Curiosity Landing Site: Clues to the Role of Wind in Landscape Modification

NASA Astrophysics Data System (ADS)

Bridges, N. T.; Le Mouélic, S.; Hallet, B.; Newman, C. E.; Rice, M. S.; Blaney, D. L.; Calef, F. J.; Herkenhoff, K. E.; Langevin, Y.; Lewis, K. W.; Maurice, S.; Pinet, P. C.; Wiens, R. C.; de Pablo, M.; Renno, N. O.

2013-12-01

The broad scale geomorphology of Gale Crater reflects diverse aeolian processes, from airfall settling that likely deposited much of the upper and some of the lower units of Mt. Sharp, to evidence of extensive wind exhumation and removal of material exterior to the mound, to active dunes on the crater floor. The integrated effect of aeolian sand transport can also be examined on a much smaller scale by the study of ventifacts, rocks that have been abraded by windborne particles. A diversity of ventifacts are found along Curiosity's traverse through the upper 'hummocky' (HY) geomorphic unit and the lower Yellowknife Bay (YKB) sedimentary rocks. The textures are analogous to abrasion features found on Earth and include cm-scale facets, keels, elongated pits, grooves, flutes, and basal sills. High-resolution images from ChemCam's Remote Micro-Imager also show mm-scale lineations. Evidence of differential erosion is common, with HY conglomerates (e.g., Hottah, Link) and the YKB Sheepbed mudstone unit containing distinct wind tails in the lee of resistant pebbles, and bedding features within Rocknest 3, the YKB Shaler sandstone unit, and other layered rocks displaying prominent ridge-groove topography. ChemCam LIBS depth profile data so far show no strong evidence for chemical differences in the elemental composition between abraded and non-abraded surfaces (as determined from qualitative assessment), as might be expected if there were rock coatings or weathering rinds undergoing active abrasion. Preliminary measurements of ventifact texture and wind tail orientations indicate sandblasting in HY and YKB from predominantly southwesterly and northerly directions, respectively. Based on meso-scale models of current winds and REMS results, SW flow is uncommon whereas N winds are frequent. Compositional and textural information from the suite of MSL instruments indicate that HY rocks are dominated by various types of basalt (either as whole rocks or the resistant clasts in conglomerates), whereas YKB are basaltic clastic rocks, with the lower members impregnated with sulfate veins, and were easily drilled. The HY rocks are therefore likely more resistant to abrasion than those of YKB. Combined, these results indicate that ventifacts so far investigated by MSL record two wind regimes, one a long-term integrated record of rare, yet strong winds and the other more reflective of typical conditions.

Prioritizing Scientific Data for Transmission

NASA Technical Reports Server (NTRS)

Castano, Rebecca; Anderson, Robert; Estlin, Tara; DeCoste, Dennis; Gaines, Daniel; Mazzoni, Dominic; Fisher, Forest; Judd, Michele

2004-01-01

A software system has been developed for prioritizing newly acquired geological data onboard a planetary rover. The system has been designed to enable efficient use of limited communication resources by transmitting the data likely to have the most scientific value. This software operates onboard a rover by analyzing collected data, identifying potential scientific targets, and then using that information to prioritize data for transmission to Earth. Currently, the system is focused on the analysis of acquired images, although the general techniques are applicable to a wide range of data modalities. Image prioritization is performed using two main steps. In the first step, the software detects features of interest from each image. In its current application, the system is focused on visual properties of rocks. Thus, rocks are located in each image and rock properties, such as shape, texture, and albedo, are extracted from the identified rocks. In the second step, the features extracted from a group of images are used to prioritize the images using three different methods: (1) identification of key target signature (finding specific rock features the scientist has identified as important), (2) novelty detection (finding rocks we haven t seen before), and (3) representative rock sampling (finding the most average sample of each rock type). These methods use techniques such as K-means unsupervised clustering and a discrimination-based kernel classifier to rank images based on their interest level.

Gold deposits of the Carolina Slate Belt, southeastern United States--Age and origin of the major gold producers

USGS Publications Warehouse

Foley, Nora K.; Ayuso, Robert A.

2012-01-01

Gold- and iron sulfide-bearing deposits of the southeastern United States have distinctive mineralogical and geochemical features that provide a basis for constructing models of ore genesis for exploration and assessment of gold resources. The largest (historic) deposits, in approximate million ounces of gold (Moz Au), include those in the Haile (~ 4.2 Moz Au), Ridgeway (~1.5 Moz Au), Brewer (~0.25 Moz Au), and Barite Hill (0.6 Moz Au) mines. Host rocks are Late Proterozoic to early Paleozoic (~553 million years old) metaigneous and metasedimentary rocks of the Carolina Slate Belt that share a geologic affinity with the classic Avalonian tectonic zone. The inferred syngenetic and epithermal-subvolcanic quartz-porphyry settings occur stratigraphically between sequences of metavolcanic rocks of the Persimmon Fork and Uwharrie Formations and overlying volcanic and epiclastic rocks of the Tillery and Richtex Formations (and regional equivalents). The Carolina Slate Belt is highly prospective for many types of gold ore hosted within quartz-sericite-pyrite altered volcanic rocks, juvenile metasedimentary rocks, and in associated shear zones. For example, sheared and deformed auriferous volcanogenic massive sulfide deposits at Barite Hill, South Carolina, and in the Gold Hill trend, North Carolina, are hosted primarily by laminated mudstone and felsic volcanic to volcaniclastic rocks. The high-sulfidation epithermal style of gold mineralization at Brewer and low-sulfidation gold ores of the Champion pit at Haile occur in breccias associated with subvolcanic quartz porphyry and within crystal-rich tuffs, ash flows, and subvolcanic rhyolite. The Ridgeway and Haile deposits are primarily epithermal replacements and feeder zones within (now) metamorphosed crystal-rich tuffs, volcaniclastic sediments, and siltstones originally deposited in a marine volcanic-arc basinal setting. Recent discoveries in the region include (1) extensions of known deposits, such as at Haile where drilling has identified an extensive gold-rich feeder system; and (2) newly discovered prospects like the porphyry-style gold-copper-molybdenum occurrence reported at Deep River, N.C. Gold ores at Ridgeway and Haile represent the low-sulfidation, disseminated, shallow subaqueous tuffaceous equivalents of intrusion-related high-sulfidation ores such as those at Brewer. Haile also has mineralogical features that support a stockwork disseminated model of pyrite-gold-sericite mineralization in which a significant amount of ore was deposited in sediments at or near the surface. The potential is high for gold-rich ore at depth in the funnel-shaped feeder zones that likely underlie such surface variants of high sulfidation–low sulfidation epithermal systems and for new discoveries of similar deposits in areas undercover. Exploration strategies for large-scale gold-mineralizing systems applied to rocks of the Carolina Slate Belt, and by extension, the Carolinian-Avalonian tectonic zone of North America, benefit from applying subvolcanic and basinal epithermal models for gold mineralization.

First Panoramic View From The Surface Of Mars

NASA Technical Reports Server (NTRS)

1976-01-01

First panoramic view by Viking 1 from the surface of Mars. (Top): The out-of-focus spacecraft component toward left center is the housing for the Viking sample arm, which is not yet deployed. Parallel lines in the sky are an artifact and are not real features. However, the change of brightness from horizon towards zenith and towards the right (west) is accurately reflected in this picture, taken in late Martian afternoon. At the horizon to the left is a plateau-like prominence much brighter than the foreground material between the rocks. The horizon features are approximately three kilometers (1.8 miles) away. At left is a collection of fine-grained material reminiscent of sand dunes. The dark sinuous markings in left foreground are of unknown origin. Some unidentified shapes can be perceived on the hilly eminence at the horizon towards the right. Patches of bright sand can be discerned among the rocks and boulders in middle distance. In right fore-ground are two peculiarly shaped rocks which may possibly be ventifacts produced by wind abrasion on Mars. A horizontal cloud stratum can be made out halfway from the horizon to the top of the picture. (Bottom): At left is seen the low gain antenna for receipt of commands from the Earth. The projections on or near the horizon may represent the rims distant impact craters. In right foreground are color charts for Lander camera calibration, a mirror for the Viking magnetic properties experiment and part of a grid on the top of the Lander body. At upper right is the high-gain dish antenna for direct communication between landed space-craft and Earth. Toward the right edge is an array of smooth fine-grained material which shows some hint of ripple structure and may be the beginning of a large dune field off to the right of the picture, which joins with dunes seen at the top left in this 300 panoramic view. Some of the rocks appear to be undercut on one side and partially buried by drifting sand on the other.

First Panoramic View From The Surface Of Mars

NASA Image and Video Library

1996-12-30

First panoramic view by Viking 1 from the surface of Mars. (Top): The out-of-focus spacecraft component toward left center is the housing for the Viking sample arm, which is not yet deployed. Parallel lines in the sky are an artifact and are not real features. However, the change of brightness from horizon towards zenith and towards the right (west) is accurately reflected in this picture, taken in late Martian afternoon. At the horizon to the left is a plateau-like prominence much brighter than the foreground material between the rocks. The horizon features are approximately three kilometers (1.8 miles) away. At left is a collection of fine-grained material reminiscent of sand dunes. The dark sinuous markings in left foreground are of unknown origin. Some unidentified shapes can be perceived on the hilly eminence at the horizon towards the right. Patches of bright sand can be discerned among the rocks and boulders in middle distance. In right fore-ground are two peculiarly shaped rocks which may possibly be ventifacts produced by wind abrasion on Mars. A horizontal cloud stratum can be made out halfway from the horizon to the top of the picture. (Bottom): At left is seen the low gain antenna for receipt of commands from the Earth. The projections on or near the horizon may represent the rims distant impact craters. In right foreground are color charts for Lander camera calibration, a mirror for the Viking magnetic properties experiment and part of a grid on the top of the Lander body. At upper right is the high-gain dish antenna for direct communication between landed space-craft and Earth. Toward the right edge is an array of smooth fine-grained material which shows some hint of ripple structure and may be the beginning of a large dune field off to the right of the picture, which joins with dunes seen at the top left in this 300 panoramic view. Some of the rocks appear to be undercut on one side and partially buried by drifting sand on the other. http://photojournal.jpl.nasa.gov/catalog/PIA00382

Hidden Outgassing Dynamics at Kilauea (Hawaii) Lava Lake

NASA Astrophysics Data System (ADS)

Del Bello, E.; Taddeucci, J.; Orr, T. R.; Houghton, B. F.; Scarlato, P.; Patrick, M. R.

2014-12-01

Lava lakes offer unique opportunities for understanding how magmatic volatiles physically escape from low-viscosity, vesicular magma in open-vent conditions, a process often referred to as magma outgassing. Large-scale lava convection movements and meter-scale bubble explosions, sometimes triggered by rock falls, are acknowledged outgassing processes but may not be the only ones. In 2013 we used high-frequency (50-500 Hz) thermal and visible imaging to investigate the short-timescale dynamics of the currently active Halema`uma`u lava lake. At that time, besides the dominant release of large bubbles, three types of peculiar outgassing features were observed on the lava lake surface. The first, diffusely observed throughout the observation experiment, consisted of prolonged (up to seconds) gas venting from 'spot vents'. These vents appeared to open and close without the ejection of material or bubble bursting, and were the site of hot gas emission. Spot vents were located both between and inside cooling plates, and followed the general circulation pattern together with the rest of the lava lake surface. The second feature, observed only once, consisted of the transient wobbling of the whole lava lake surface. This wobbling, with a wavelength of meters to tens of meters, was not related to any external trigger, and dampened soon without apparent consequences on the other lake dynamics. Finally, we observed large (meters) doming areas of the lake surface randomly fluctuating over seconds to minutes. These areas were either stationary or moved independently of the general lake surface circulation, and usually were not affected by other lake surface features (e.g., cooling plate boundaries). These three features, though trivial for the overall lake outgassing, testify that the lava lake has a complex shallow subsurface architecture, in which permeable channels and gas pockets act independently of the more common bubble bursts.

Combination of minimum enclosing balls classifier with SVM in coal-rock recognition.

PubMed

Song, QingJun; Jiang, HaiYan; Song, Qinghui; Zhao, XieGuang; Wu, Xiaoxuan

2017-01-01

Top-coal caving technology is a productive and efficient method in modern mechanized coal mining, the study of coal-rock recognition is key to realizing automation in comprehensive mechanized coal mining. In this paper we propose a new discriminant analysis framework for coal-rock recognition. In the framework, a data acquisition model with vibration and acoustic signals is designed and the caving dataset with 10 feature variables and three classes is got. And the perfect combination of feature variables can be automatically decided by using the multi-class F-score (MF-Score) feature selection. In terms of nonlinear mapping in real-world optimization problem, an effective minimum enclosing ball (MEB) algorithm plus Support vector machine (SVM) is proposed for rapid detection of coal-rock in the caving process. In particular, we illustrate how to construct MEB-SVM classifier in coal-rock recognition which exhibit inherently complex distribution data. The proposed method is examined on UCI data sets and the caving dataset, and compared with some new excellent SVM classifiers. We conduct experiments with accuracy and Friedman test for comparison of more classifiers over multiple on the UCI data sets. Experimental results demonstrate that the proposed algorithm has good robustness and generalization ability. The results of experiments on the caving dataset show the better performance which leads to a promising feature selection and multi-class recognition in coal-rock recognition.

Combination of minimum enclosing balls classifier with SVM in coal-rock recognition

PubMed Central

Song, QingJun; Jiang, HaiYan; Song, Qinghui; Zhao, XieGuang; Wu, Xiaoxuan

2017-01-01

Top-coal caving technology is a productive and efficient method in modern mechanized coal mining, the study of coal-rock recognition is key to realizing automation in comprehensive mechanized coal mining. In this paper we propose a new discriminant analysis framework for coal-rock recognition. In the framework, a data acquisition model with vibration and acoustic signals is designed and the caving dataset with 10 feature variables and three classes is got. And the perfect combination of feature variables can be automatically decided by using the multi-class F-score (MF-Score) feature selection. In terms of nonlinear mapping in real-world optimization problem, an effective minimum enclosing ball (MEB) algorithm plus Support vector machine (SVM) is proposed for rapid detection of coal-rock in the caving process. In particular, we illustrate how to construct MEB-SVM classifier in coal-rock recognition which exhibit inherently complex distribution data. The proposed method is examined on UCI data sets and the caving dataset, and compared with some new excellent SVM classifiers. We conduct experiments with accuracy and Friedman test for comparison of more classifiers over multiple on the UCI data sets. Experimental results demonstrate that the proposed algorithm has good robustness and generalization ability. The results of experiments on the caving dataset show the better performance which leads to a promising feature selection and multi-class recognition in coal-rock recognition. PMID:28937987

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

Some of the moving rocks are large. This one is about 10 inches tall. Researchers in the late 1960s and early 1970s documented the movements of one very large rock that they named Karen. (The two men named all the rocks after women.) They estimated that Karen weighed 700 pounds. Credit: NASA/GSFC/Maggie McAdam To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

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

NASA Technical Reports Server (NTRS)

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

1975-01-01

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

A Tale of 3 Craters

NASA Technical Reports Server (NTRS)

2004-01-01

11 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image captures some of the complexity of the martian upper crust. Mars does not simply have an impact-cratered surface, it's upper crust is a cratered volume. Over time, older craters on Mars have been eroded, filled, buried, and in some cases exhumed and re-exposed at the martian surface. The crust of Mars is layered to depths of 10 or more kilometers, and mixed in with the layered bedrock are a variety of ancient craters with diameters ranging from a few tens of meters (a few tens of yards) to several hundred kilometers (more than one or two hundred miles).

The picture shown here captures some of the essence of the layered, cratered volume of the upper crust of Mars in a very simple form. The image shows three distinct circular features. The smallest, in the lower right quarter of the image, is a meteor crater surrounded by a mound of material. This small crater formed within a layer of bedrock that once covered the entire scene, but today is found only in this small remnant adjacent to the crater. The intermediate-sized crater, west (left) of the small one, formed either in the next layer down--that is, below the layer in which the small crater formed--or it formed in some layers that are now removed, but was big enough to penetrate deeply into the rock that is near the surface today. The largest circular feature in the image, in the upper right quarter of the image, is still largely buried. It formed in layers of rock that are below the present surface. Erosion has brought traces of its rim back to the surface of Mars. This picture is located near 50.0oS, 77.8oW, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates this October 2004 image from the upper left.

Do Bare Rocks Exist on the Moon?

NASA Technical Reports Server (NTRS)

Allen, Carlton; Bandfield, Joshua; Greenhagen, Benjamin; Hayne, Paul; Leader, Frank; Paige, David

2017-01-01

Astronaut surface observations and close-up images at the Apollo and Chang'e 1 landing sites confirm that at least some lunar rocks have no discernable dust cover. However, ALSEP (Apollo Lunar Surface Experiments Package) measurements as well as astronaut and LADEE (Lunar Atmosphere and Dust Environment Explorer) orbital observations and laboratory experiments possibly suggest that a fine fraction of dust is levitated and moves across and above the lunar surface. Over millions of years such dust might be expected to coat all exposed rock surfaces. This study uses thermal modeling, combined with Diviner (a Lunar Reconnaissance Orbiter experiment) orbital lunar eclipse temperature data, to further document the existence of bare rocks on the lunar surface.

Radar-anomalous, high-altitude features on Venus

NASA Technical Reports Server (NTRS)

Muhleman, Duane O.; Butler, Bryan J.

1992-01-01

Over nearly all of the surface of Venus the reflectivity and emissivity at centimeter wavelengths are about 0.15 and 0.85 respectively. These values are consistent with moderately dense soils and rock populations, but the mean reflectivity is about a factor of 2 greater than that for the Moon and other terrestrial planets. Pettingill and Ford, using Pioneer Venus reflectivities and emissivities, found a number of anomalous features on Venus that showed much higher reflectivities and much lower emissivities with both values approaching 0.5. These include Maxwell Montes, a number of high regions in Aphrodite Terra and Beta Regio, and several isolated mountain peaks. Most of the features are at altitudes above the mean radius by 2 to 3 km or more. However, such features have been found in the Magellan data at low altitudes and the anomalies do not exist on all high structures, Maat Mons being the most outstanding example. A number of papers have been written that attempt to explain the phenomena in terms of the geochemistry balance of weathering effects on likely surface minerals. The geochemists have shown that the fundamentally basaltic surface would be stable at the temperatures and pressures of the mean radius in the form of magnetite, but would evolve to pyrite and/or pyrrhotite in the presence of sulfur-bearing compounds such as SO2. Pyrite will be stable at altitudes above 4 or 5 km on Venus. Although the geochemical arguments are rather compelling, it is vitally important to rationally look at other explanations for radar and radio emission measurements such as that presented by Tryka and Muhleman. The radar reflectivity values are retrieved from the raw Magellan backscatter measurements by fitting the Hagfors' radar scattering model in which a surface roughness parameters and a normal incidence electrical reflectivity are estimated. The assumptions of the theory behind the model must be considered carefully before the results can be believed. These include that the surface roughness exists only at horizontal scales large compared to the wavelength, the vertical deviations are gaussianly distributed, there is no shadowing, and that the reflection occurs at the interface of two homogeneous dielectric half-spaces. Probably all these conditions are violated at the anomalous features under discussion. The most important of these is the homogeneity of the near surface of Venus, particularly in highlands. Under the assumptions of the theory, all of the radio energy is reflected by the impedance jump at the very boundary. However, in heterogeneous soil some fraction of the illuminating energy is propagated into the soil and then scattered back out by impedance discontinuities such as rock, voids, and cracks. In light soils, the latter effect can overwhelm the scattering effects of the true surface and greatly enhance the backscatter power, suggesting a much higher value of an effective dielectric constant that would be estimated from Hagfors' model.

Scene analysis for a breadboard Mars robot functioning in an indoor environment

NASA Technical Reports Server (NTRS)

Levine, M. D.

1973-01-01

The problem is delt with of computer perception in an indoor laboratory environment containing rocks of various sizes. The sensory data processing is required for the NASA/JPL breadboard mobile robot that is a test system for an adaptive variably-autonomous vehicle that will conduct scientific explorations on the surface of Mars. Scene analysis is discussed in terms of object segmentation followed by feature extraction, which results in a representation of the scene in the robot's world model.

Ripples in Rocks Point to Water

NASA Technical Reports Server (NTRS)

2004-01-01

This image taken by the Mars Exploration Rover Opportunity's panoramic camera shows the rock nicknamed 'Last Chance,' which lies within the outcrop near the rover's landing site at Meridiani Planum, Mars. The image provides evidence for a geologic feature known as ripple cross-stratification. At the base of the rock, layers can be seen dipping downward to the right. The bedding that contains these dipping layers is only one to two centimeters (0.4 to 0.8 inches) thick. In the upper right corner of the rock, layers also dip to the right, but exhibit a weak 'concave-up' geometry. These two features -- the thin, cross-stratified bedding combined with the possible concave geometry -- suggest small ripples with sinuous crest lines. Although wind can produce ripples, they rarely have sinuous crest lines and never form steep, dipping layers at this small scale. The most probable explanation for these ripples is that they were formed in the presence of moving water.

Crossbedding Evidence for Underwater Origin Interpretations of cross-lamination patterns presented as clues to this martian rock's origin under flowing water are marked on images taken by the panoramic camera and microscopic imager on NASA's Opportunity.

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

The red arrows (Figure 1) point to features suggesting cross-lamination within the rock called 'Last Chance' taken at a distance of 4.5 meters (15 feet) during Opportunity's 17th sol (February 10, 2004). The inferred sets of fine layers at angles to each other (cross-laminae) are up to 1.4 centimeters (half an inch) thick. For scale, the distance between two vertical cracks in the rock is about 7 centimeters (2.8 inches). The feature indicated by the middle red arrow suggests a pattern called trough cross-lamination, likely produced when flowing water shaped sinuous ripples in underwater sediment and pushed the ripples to migrate in one direction. The direction of the ancient flow would have been either toward or away from the line of sight from this perspective. The lower and upper red arrows point to cross-lamina sets that are consistent with underwater ripples in the sediment having moved in water that was flowing left to right from this perspective.

The yellow arrows (Figure 2) indicate places in the panoramic camera view that correlate with places in the microscope's view of the same rock.

[figure removed for brevity, see original site] Figure 3

The microscopic view (Figure 3) is a mosaic of some of the 152 microscopic imager frames of 'Last Chance' that Opportunity took on sols 39 and 40 (March 3 and 4, 2004).

[figure removed for brevity, see original site] Figure 4

Figure 4 shows cross-lamination expressed by lines that trend downward from left to right, traced with black lines in the interpretive overlay. These cross-lamination lines are consistent with dipping planes that would have formed surfaces on the down-current side of migrating ripples. Interpretive blue lines indicate boundaries between possible sets of cross-laminae.

Geological characterization of remote field sites using visible and infrared spectroscopy: Results from the 1999 Marsokhod field test

USGS Publications Warehouse

Johnson, J. R.; Ruff, S.W.; Moersch, J.; Roush, T.; Horton, K.; Bishop, J.; Cabrol, N.A.; Cockell, C.; Gazis, P.; Newsom, Horton E.; Stoker, C.

2001-01-01

Upcoming Mars Surveyor lander missions will include extensive spectroscopic capabilities designed to improve interpretations of the mineralogy and geology of landing sites on Mars. The 1999 Marsokhod Field Experiment (MFE) was a Mars rover simulation designed in part to investigate the utility of visible/near-infrared and thermal infrared field spectrometers to contribute to the remote geological exploration of a Mars analog field site in the California Mojave Desert. The experiment simultaneously investigated the abilities of an off-site science team to effectively analyze and acquire useful imaging and spectroscopic data and to communicate efficiently with rover engineers and an on-site field team to provide meaningful input to rover operations and traverse planning. Experiences gained during the MFE regarding effective communication between different mission operation teams will be useful to upcoming Mars mission teams. Field spectra acquired during the MFE mission exhibited features interpreted at the time as indicative of carbonates (both dolomitic and calcitic), mafic rocks and associated weathering products, and silicic rocks with desert varnish-like coatings. The visible/near-infrared spectra also suggested the presence of organic compounds, including chlorophyll in one rock. Postmission laboratory petrologic and spectral analyses of returned samples confirmed that all rocks identified as carbonates using field measurements alone were calc-silicates and that chlorophyll associated with endolithic organisms was present in the one rock for which it was predicted. Rocks classified from field spectra as silicics and weathered mafics were recognized in the laboratory as metamorphosed monzonites and diorite schists. This discrepancy was likely due to rock coatings sampled by the field spectrometers compared to fresh rock interiors analyzed petrographically, in addition to somewhat different surfaces analyzed by laboratory thermal spectroscopy compared to field spectra. Copyright 2001 by the American Geophysical Union.

Revised Thorium Abundances for Lunar Red Spots

NASA Technical Reports Server (NTRS)

Hagerty, J. J.; Lawrence, D. J.; Elphic, R. C.; Feldman, W. C.; Vaniman, D. T.; Hawke, B. R.

2005-01-01

Lunar red spots are features on the nearside of the Moon that are characterized by high albedo and by a strong absorption in the ultraviolet. These red spots include the Gruithuisen domes, the Mairan domes, Hansteen Alpha, the southern portion of Montes Riphaeus, Darney Chi and Tau, Helmet, and an area near the Lassell crater. It has been suggested that many of the red spots are extrusive, nonmare, volcanic features that could be composed of an evolved lithlogy enriched in thorium. In fact, Hawke et al. used morphological characteristics to show that Hansteen Alpha is a nonmare volcanic construct. However, because the apparent Th abundances (6 - 7 ppm) were lower than that expected for evolved rock types, Hawke et al. concluded that Hansteen Alpha was composed of an unknown rock type. Subsequent studies by Lawrence et al. used improved knowledge of the Th spatial distribution for small area features on the lunar surface to revisit the interpretation of Th abundances at the Hansteen Alpha red spot. As part of their study, Lawrence et al. used a forward modeling technique to show that the Th abundance at Hansteen Alpha is not 6 ppm, but is more likely closer to 25 ppm, a value consistent with evolved lithologies. This positive correlation between the morphology and composition of Hansteen Alpha provides support for the presence of evolved lithologies on the lunar surface. It is possible, however, that Hansteen Alpha represents an isolated occurrence of non-mare volcanism. That is why we have chosen to use the forward modeling technique of Lawrence et al. to investigate the Th abundances at other lunar red spots, starting with the Gruithuisen domes. Additional information is included in the original extended abstract.

Kaolinite, illite and quartz dissolution in the karstification of Paleozoic sandstones of the Furnas Formation, Paraná Basin, Southern Brazil

NASA Astrophysics Data System (ADS)

Melo, Mário Sérgio de; Guimarães, Gilson Burigo; Chinelatto, Adilson Luiz; Giannini, Paulo César Fonseca; Pontes, Henrique Simão; Chinelatto, Adriana Scoton Antonio; Atencio, Daniel

2015-11-01

Karstification processes in sandstones of the Furnas Formation, Silurian to Devonian of the Paraná Basin, have been described since the mid-twentieth century. However, some geologists still doubt the idea of true karst in sandstones. Studies carried out in the Campos Gerais region, Paraná State, Southern Brazil, aimed at investigating the nature of erosion processes in Furnas Formation and the role of the dissolution in the development of their notorious erosive features and underground cavities. These studies have led to the recognition of dissolution macro to micro features ('furnas', caves, ponds, sinks, ruiniform relief on cliffs and rocky surfaces, grain corrosion, speleothems, mineral reprecipitation and incrustation). The analysis (scanning electron microscopy, energy dispersive spectrometry and x-ray diffractometry) of sandstones and their alterites has indicated significant dissolution of clay cement along with discrete quartz grain dissolution. This mesodiagenetic cement (kaolinite and illite) is dissolved and reprecipitated as clay minerals with poorly developed crystallinity along with other minerals, such as variscite and minerals of the alunite supergroup, suggesting organic participation in the processes of dissolution and incrustation. The mineral reprecipitation usually forms centimetric speleothems, found in cavities and sheltered rocky surfaces. The cement dissolution associated with other factors (fractures, wet weather, strong hydraulic gradient, antiquity of the landforms) leads to the rock arenisation, the underground erosion and the appearance of the karst features. Carbonate rocks in the basement may locally be increasing the karst forms in the overlying Furnas Formation. The recognition of the karst character of the Furnas Formation sandstones has important implications in the management of underground water resources (increasingly exploited in the region), in the use of the unique geological heritage and in the prevention of geo-environmental accidents resulting from underground erosion phenomena.

Using earthquake-triggered landslides as a hillslope-scale shear strength test: Insights into rock strength properties at geomorphically relevant spatial scales in high-relief, tectonically active settings

NASA Astrophysics Data System (ADS)

Gallen, Sean; Clark, Marin; Godt, Jonathan; Lowe, Katherine

2016-04-01

The material strength of rock is known to be a fundamental property in setting landscape form and geomorphic process rates as it acts to modulate feedbacks between earth surface processes, tectonics, and climate. Despite the long recognition of its importance in landscape evolution, a quantitative understanding of the role of rock strength in affecting geomorphic processes lags our knowledge of the influence of tectonics and climate. This gap stems largely from the fact that it remains challenging to quantify rock strength at the hillslope scale. Rock strength is strongly scale dependent because the number, size, spacing, and aperture of fractures sets the upper limit on rock strength, making it difficult to extrapolate laboratory measurements to landscape-scale interpretations. Here we present a method to determine near-surface rock strength at the hillslope-scale, relying on earthquake-triggered landslides as a regional-scale "shear strength" test. We define near-surface strength as the average strength of rock sample by the landslides, which is typically < 10 m. Based on a Newmark sliding block model, which approximates slope stability during an earthquake assuming a material with frictional and cohesive strength, we developed a coseismic landslide model that is capable of reproducing statistical characteristics of the distribution of earthquake-triggered landslides. We present results from two well-documented case-studies of earthquakes that caused widespread mass-wasting; the 2008 Mw 7.9 Wenchuan Earthquake, Sichuan Province, China and the 1994 Mw. 6.8 Northridge Earthquake, CA, USA. We show how this model can be used to determine near-surface rock strength and reproduce mapped landslide patterns provided the spatial distribution of local hillslope gradient, earthquake peak ground acceleration (PGA), and coseismic landsliding are well constrained. Results suggest that near-surface rock strength in these tectonically active settings is much lower than that obtained using typical laboratory shear strength measurements on intact rock samples. Furthermore, the near-surface material strength is similar between the study areas despite differences in tectonic, climatic, and lithologic conditions. Variations in near-surface strength within each setting appear to be more strongly associated with factors contributing to the weakening rock through chemical or physical weathering, such as mean annual precipitation and distance to active faults (a proxy for rock shattering intensity), rather than intrinsic lithologic properties. We hypothesize that the shattering of rock through long-term permanent strain accumulation and by repeated earthquakes is an important mechanism that can explain low rock strength values among the different study sites and the spatial pattern of rock strength within each location. These findings emphasize the potential role of factors other than lithology in controlling the spatial distribution of near-surface rock strength in high-relief, tectonically active settings, which has important implications for understanding the evolution of landscapes, interpreting tectonic and climatic signals from topography, critical zone processes, and natural hazard assessment.

Trace-element evidence for the origin of desert varnish by direct aqueous atmospheric deposition

NASA Astrophysics Data System (ADS)

Thiagarajan, Nivedita; Aeolus Lee, Cin-Ty

2004-07-01

Smooth rock surfaces in arid environments are often covered with a thin coating of Fe-Mn oxyhydroxides known as desert varnish. It is debated whether such varnish is formed (a) by slow diagenesis of dust particles deposited on rock surfaces, (b) by leaching from the underlying rock substrate, or (c) by direct deposition of dissolved constituents in the atmosphere. Varnishes collected from smooth rock surfaces in the Mojave Desert and Death Valley, California are shown here to have highly enriched and fractionated trace-element abundances relative to upper continental crust (UCC). They are highly enriched in Co, Ni, Pb and the rare-earth elements (REEs). In particular, they have anomalously high Ce/La and low Y/Ho ratios. These features can only be explained by preferential scavenging of Co, Ni, Pb and the REEs by Fe-Mn oxyhydroxides in an aqueous environment. High field strength elements (HFSEs: Zr, Hf, Ta, Nb, Th), however, show only small enrichments despite the fact that these elements should also be strongly scavenged by Fe-Mn oxyhydroxides. This suggests that their lack of enrichment is a feature inherited from a solution initially poor in HFSEs. The first two scenarios for varnish formation can be ruled out as follows. The high enrichment factors of Fe, Mn and many trace elements cannot be generated by mass loss associated with post-depositional diagenesis of dust particles because such a process predicts only a small increase in concentration. In addition, the highly fractionated abundance patterns of particle reactive element pairs (e.g., Ce/La and Y/Ho) rules out leaching of the rock substrate. This is because if leaching were to occur, varnishes would grow from the inside to the outside, and thus any particle-reactive trace element leached from the substrate would be quantitatively sequestered in the Fe-Mn oxyhydroxide layers, prohibiting any significant elemental fractionations. One remaining possibility is that the Fe, Mn and trace metals in varnish are derived from leaching of dust particles entrained in rain or fog droplets either in the atmosphere or during wet atmospheric deposition. The high trace metal enrichment factors require that most of the dust was physically removed before or during varnish formation. The remaining aqueous counterpart would be depleted in HFSEs and Th relative to the REEs, Co, Ni and Pb because the former are more insoluble and hence largely retained in the removed dust fraction. The high Ce/La ratios suggest that precipitation of trace metals may have been governed by equilibrium partitioning in an excess of wet atmospheric deposition. If varnishes are indeed derived from wet atmospheric deposition, they may provide a record of the aqueous component of atmospheric dust inputs to various environments.

Goechemical and Hydrogeochemical Properties of Cappadocia Geothermal Province

NASA Astrophysics Data System (ADS)

Furkan Sener, Mehmet; Sener, Mehmet; Uysal, Tonguc

2016-04-01

In order to determine the geothermal resource potential of Niǧde, Nevşehir and Aksaray provinces in Central Anatolian Volcanic Province (CAVP), geothermal fluids, surface water, and alteration rock samples from the Cappadocia volcanic zone in Turkey were investigated for their geochemical and stable isotopic characteristics in light of published geological and tectonic studies. Accordingly, the Cappadocia Geothermal Province (CGP) has two different geothermal systems located along tectonic zones including five active and two potential geothermal fields, which are located between Tuzgölü Fault Zone and Keçiboyduran-Melendiz Fault and north of Keçiboyduran-Melendiz Fault. Based on water chemistry and isotope compositions, samples from the first area are characterized by Ca-Mg-HCO3 ve Ca-HCO3 type mineral poor waters and Ca-Na-SO4 and Ca-Mg-SO4 type for the cold waters and the hot waters, respectively, whereas hot waters from the second area are Na-Cl-HCO3 and Ca-Na-HCO3 type mineral poor waters. According to δ18O and δ2H isotope studies, the geothermal waters are fed from meteoric waters. Results of silica geothermometer indicate that the reservoir temperature of Dertalan, Melendiz Mount, Keçiboyduran Mount, Hasan Mount (Keçikalesi), Ziga, Acıgöl, and Derinkuyu geothermal waters are 150-173 oC, 88-117 oC, 91-120 oC, 94-122 oC, 131-156 oC, 157-179 oC; 152-174 oC and 102-130 oC, respectively. The REE composition of geothermal fluids, surface water, and mineral precipitates indicate that temperature has a strong effect on REE fractionation of the sampled fluids. Eu- and Ce- anomalies (Eu/Eu*, Ce/Ce*) are visible in several samples, which are related to the inheritance from the host reservoir rocks and redox-controlled fractionation of these elements during water-rock interactions. REE and Yttrium geochemistry results of altered rock samples and water samples, which were taken from same locations exhibited quite similar features in each system. Hence, it was conclude that the same hydrothermal fluid in geothermal system was reached to the surface and interacted with the surface rocks. Our conceptual geothermal model for Cappadocia Geothermal Province based on our geochemical and hydrogeochemical data in combination with geological and geophysical information suggest that the geothermal resources in this region are controlled by primary (active fault) and secondary (buried fault) tectonic belts. Further, our geochemical data indicate the Paleozoic-Mesozoic marble and gneiss being the reservoir rocks. Geogradient and impending heat fluxes to the surface with a possible crustal thinning, which was developed after regional tectonic activities during the Late Pliocene-Quaternary period, constitutes the heat sources. In addition, our study suggest that the Quaternary tuff and ignimbrites of Cappadocia Volcanics represent the seal rock of the geothermal system. In conclusion this study provide evidence for a significant geothermal potential in the Cappadocia region with well-defined seal rocks. However, further studies are needed to resolve the geothermal fluid source problem. Keywords: Cappadocia, geothermal systems, geochemistry, rare earth elements, hydrogeochemistry, hydrothermal alteration.

Lunar Science Conference, 8th, Houston, Tex., March 14-18, 1977, Proceedings. Volume 1 - The moon and the inner solar system. Volume 2 - Petrogenetic studies of mare and highland rocks. Volume 3 - Planetary and lunar surfaces

NASA Technical Reports Server (NTRS)

Merril, R. B.

1977-01-01

Solar system processes are considered along with the origin and evolution of the moon, planetary geophysics, lunar basins and crustal layering, lunar magnetism, the lunar surface as a planetary probe, remote observations of lunar and planetary surfaces, earth-based measurements, integrated studies, physical properties of lunar materials, and asteroids, meteorites, and the early solar system. Attention is also given to studies of mare basalts, the kinetics of basalt crystallization, topical studies of mare basalts, highland rocks, experimental studies of highland rocks, geochemical studies of highland rocks, studies of materials of KREEP composition, a consortium study of lunar breccia 73215, topical studies on highland rocks, Venus, and regional studies of the moon. Studies of surface processes, are reported, taking into account cratering mechanics and fresh crater morphology, crater statistics and surface dating, effects of exposure and gardening, and the chemistry of surfaces.

Field evidence for control of quarrying by rock bridges in jointed bedrock

NASA Astrophysics Data System (ADS)

Hooyer, T. S.; Cohen, D. O.; Iverson, N. R.

2011-12-01

Quarrying is generally thought to be the most important mechanism by which glaciers erode bedrock. In quarrying models it is assumed that slow, subcritical, growth of pre-existing cracks rate-limits the process and occurs where there are large stress differences in the bed, such as near rock bumps where ice separates from the bed to form water-filled cavities. Owing to the direction of principal stresses in rocks associated with sliding and resultant cavity formation, models predict that quarrying will occur along cracks oriented perpendicular to the ice flow direction or parallel to zones of ice-bed contact. Preglacial cracks in rocks will tend to propagate mainly downward, and in sedimentary or some metamorphic rocks will merge with bedding planes, thereby helping to isolate rock blocks for dislodgement. In contrast to these model assumptions, new measurements of quarried surface orientations in the deglaciated forefield of nine glaciers in Switzerland and Canada indicate a strong correlation between orientations of pre-existing joints and quarried bedrock surfaces, independent of ice flow direction or ice-water contact lines. The strong correlation persists across all rock types, and rocks devoid of major joints lack quarried surfaces. We propose a new conceptual model of quarrying that idealizes the bedrock as a series of blocks separated by discontinuous preglacial joints containing intact rock bridges. Bridges concentrate stress differences caused by normal and shear forces acting at the rock surface. Failure of bridges is caused by slow subcritical crack growth enhanced by water pressure fluctuations. To lend credibility to this new model, we show field evidence of failed rock bridges in quarried surfaces and of rib marks on plumose structures that we interpret as arrest fracture fronts due to transient subglacial water-pressure fluctuations.

Earth Observations taken by the Expedition 15 Crew

NASA Image and Video Library

2007-05-13

ISS015-E-07928 (13 May 2007) --- Isla San Lorenzo and Isla Las Animas are featured in this image photographed by an Expedition 15 crewmember on the International Space Station. Located in the northern Gulf of California, Isla (island) San Lorenzo and Isla Las Animas -- part of the Midriff Islands -- record geologic processes involved in the creation of the Baja California peninsula over several hundred million years, according to scientists. A geologist walking along the 17-kilometer long central ridge of Isla San Lorenzo from the southeastern to the northwestern end would first encounter Cretaceous granitic rock in the southeastern third of the island (light tan, center left). The central third of the island is comprised mainly of older Paleozoic metamorphic rocks (brown, center; directly above "Isla San Lorenzo"). Together, these very old rocks form the crystalline "basement" of the island. The northwestern third of Isla San Lorenzo, and much of adjacent Isla Las Animas, is composed of much more recent volcanic and marine sedimentary rocks (yellow-brown to light brown, center right). According to scientists, these rocks were formed by volcanoes and fissure eruptions in and around basins in the growing Gulf of California between 5-8 million years ago. The islands themselves were formed as a result of uplift of crustal blocks along the southeastward-trending San Andreas Fault. This image illustrates the largely pristine nature of these islands. The islands are located in the rain shadow of mountains on the Baja Peninsula to the west, and arid conditions prevail through much of the year. The scarcity of water has limited human presence on the islands, and allowed flora and fauna unique to each island (known as endemic species) to flourish -- particularly reptiles. The islands are also home to colonies of seabirds and seals, both of which take advantage of deep productive waters adjacent to the eastern Baja coast. Shallow waters and high levels of nutrients can also lead to blooms of green phytoplankton; two such blooms can be seen along the coastline of Isla Las Animas (center right, in north and west-facing embayments). Surface water patterns around the islands -- enhanced by sunlight reflectance off the water surface -- are due to wind- and current-induced roughness (silver-gray regions). Regions of dark blue water are indicative of calm surface conditions, or the presence of oils and surfactants that decrease surface tension.

Interannual variability of rock glacier surface velocities and its relationship to climatic conditions on a decadal scale: Some insights from the European Alps

NASA Astrophysics Data System (ADS)

Kellerer-Pirklbauer, Andreas; Bodin, Xavier; Delaloye, Reynald; Fischer, Andrea; Gärtner-Roer, Isabelle; Hartl, Lea; Kaufmann, Viktor; Krainer, Karl; Lambiel, Christophe; Mair, Volkmar; Marcer, Marco; Morra di Cella, Umberto; Scapozza, Cristian; Schoeneich, Philippe; Staub, Benno

2017-04-01

Active, inactive and relict rock glaciers are widespread periglacial landforms in the European Alps as revealed by several inventories elaborated for Slovenia, Austria, Switzerland, Italy, and France. Rock glaciers indicate present or past permafrost conditions in mountain environments and hence have a high climatic or paleoclimatic relevance. The monitoring of surface velocities at active rock glaciers has a long tradition in the European Alps with first terrestrial photogrammetric surveys in the Swiss and Austrian Alps already in the 1920s. Since the 1990s velocity monitoring activities have been substantially expanded but also institutionalized. Today, several research groups carry out annual or even continuous monitoring of rock glacier creep at more than 30 rock glaciers in Austria, France, Italy, and Switzerland. In many cases such a kinematic monitoring is jointly accomplished with meteorological and ground temperature monitoring in order to better understand the rock glacier-climate relationships and the reaction of rock glacier behavior to climatic changes. In this contribution we present a synthesis of the main results from long-term monitoring of several rock glaciers in the European Alps with at least annually-repeated data. Similarities but also differences of the movement patterns at the different sites are discussed, while the spatio-temporal pattern of the surface displacement is looked at against the climate context. In general, rock glacier surface velocities in the European Alps have been rather low during the 1980s and 1990s and reached a first peak in 2003/04 followed by a drastic drop until c.2007/08. Since then rock glacier surface velocities increased again with new velocity records in 2015/16 superior to the first peak around 2003/04. These creep rate maxima coincide with the warmest permafrost temperatures ever measured in boreholes and are likely a result of the continuously warm conditions at the ground surface over the past seven years.

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

The rocks at Racetrack Playa in Death Valley, Calif., are famous. Photo credit: NASA/GSFC/Maggie McAdam To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

New data concerning the age and specific features of magmatism of timanides in the southern part of the Lyapin structure (Northern Urals)

NASA Astrophysics Data System (ADS)

Petrov, G. A.; Ronkin, Yu. L.; Gerdes, A.; Maslov, A. V.

2017-10-01

New data on composition and age of Precambrian granites and volcanic rocks in the southern part of the Lyapin structure (Northern Urals) are considered. The geochemical features of the igneous rocks are similar to those of the rocks formed in both divergent and convergent environments. In the Late Precambrian (583-553 Ma), the investigated area is assumed to have been a part of the active margin above the mantle plume.

Physical properties of the surface materials at the Viking landing sites on Mars

USGS Publications Warehouse

Moore, H.J.; Hutton, R.E.; Clow, G.D.; Spitzer, C.R.

1987-01-01

This report summarizes the results of the Physical Properties Investigation of the Viking '75 Project, activities of the surface samplers, and relevant results from other investigations. The two Viking Landers operated for nearly four martian years after landing on July 20 (Lander 1) and Sept. 3 (Lander 2), 1976; Lander 1 acquired its last pictures on or about Nov. 5, 1982. Lander 1 rests on a smooth, cratered plain at the west edge of Chryse Planitia (22.5 ? N, 48.0? W), and Lander 2 rests 200 km west of the crater Mie in Utopia Planitia (48.0? N, 225.7? W). Lander 1 views showed that dune-like deposits of drift material were superposed on rock-strewn surfaces. Soil-like material from the rock-strewn areas was called blocky material. Lander 2 views also showed a rock-strewn surface. Polygonal to irregular features, etched by the wind, revealed crusty to cloddy material among rocks. Both landers descended to the surface along nearly vertical trajectories. Velocities at touchdown were about 2 m/s for both landers. Footpad 2 of Lander 1 penetrated drift material 0.165 m, and footpad 3 penetrated blocky material 0.036 m. The two visible footpads of Lander 2 struck rocks. Erosion by exhausts from the forward engines produced craters with rims of mixed fine-grained material and platy to equidimensional clods, crusts, and fragments. Comparison of engine-exhaust erosion on Mars with terrestrial data suggested that drift material behaved like a weakly cohesive material with a grain size less than 3-9 /-lm. Although not sand, blocky and crusty to cloddy materials eroded like sand-with grain sizes of 0.01 or 0.2 cm. The surface samplers accomplished an impressive number of tasks. All experiments that required samples received samples. Deep holes, as much as 0.22 m deep, were excavated by both landers. Lander 2 successfully pushed rocks and collected samples from areas originally beneath the rocks. Tasks specifically accomplished for the Physical Properties Investigation include: (1) acquiring motor-current data while excavating trenches, (2) performing surface-bearing tests, (3) performing backhoe touchdowns, (4) attempting to chip or scratch rocks, (5) comminuting samples, (6) measuring subsurface diurnal temperatures, and (7) constructing conical piles of materials on and among rocks. Sample trenches in the three major types of soil-like materials were different from one another. Trenches in drift material, which were typically 0.06 m deep, had steep walls along much of their lengths, lumpy tailings and floors, and smooth domed surfaces with sparse fine fractures around their tips. Trenches in blocky material, which were typically 0.03-0.04 m deep, had steep walls near their tips, and surfaces around their tips were displaced upward and some appeared blocky. Trenches in crusty to cloddy material, which were typically 0.04-0.05 m deep, had steep and often irregular slopes near their tips, clods and slabs of crust in their tailings, and disrupted areas around their tips composed of mixed fine-grained material and slabs of crust or thick polygonal clods that had been displaced upwards. Data acquired during landing, trenching, surface-bearing tests, backhoe touchdowns, and from other science experiments were used to determine the mechanical properties of drift, blocky, and crusty to cloddy materials. Drift material appeared to be very fine grained, with local planes of weakness; in general, the drift material was consistent with a material having an angle of internal friction about 18?, a cohesion ranging from 0.7 to 3.0 kPa, and a bulk density of 1,200 kg/m 3 . Blocky material was consistent with a material having an angle of internal friction about 30?, cohesions from 1.5 to 16 kPa, and a bulk density of 1,600 kg/m 3 . Crusty to cloddy material had variable properties. For chiefly crusty to cloddy material, angles of internal friction were about 35 ? , and cohesions were from 0.5 to 5.2 kPa. For mixed fines and crusts, a

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.

Evolution of late stage differentiates in the Palisades Sill, New York and New Jersey

NASA Astrophysics Data System (ADS)

Block, Karin A.; Steiner, Jeffrey C.; Puffer, John H.; Jones, Kevin M.; Goldstein, Steven L.

2015-08-01

The Palisades Sill at Upper Nyack, NY contains evolved rocks that crystallized as ferrodiabase and ferrogranophyre and occupy 50% to 60% of the local thickness. 143Nd/144Nd isotope values for rocks representing Palisades diversity range between 0.512320 and 0.512331, and indicate a homogeneous source for the Palisades and little or no contamination from shallow crustal sediments. Petrographic analysis of ferrodiabase suggests that strong iron enrichment was the result of prolonged quiescence in cycles of magmatic input. Ferrogranophyres in the updip northern Palisades at Upper Nyack are members of a suite of cogenetic rocks with similar composition to 'sandwich horizon' rocks of the southern Palisades at Fort Lee, NJ, but display distinct mineralogical and textural features. Differences in textural and mineralogical features are attributed to a) updip (lateral) migration of residual liquid as the sill propagated closer to the surface; b) deformation caused by tectonic shifts; and c) crystallization in the presence of deuteric hydrothermal fluids resulting in varying degrees of alteration. A model connecting multiple magmatic pulses, compaction and mobilization of residual liquid by compositional convection, closed-system differentiation, synchronous with tapping of the sill for extrusion of coeval basaltic subaerial flows is presented. The persistence of a low-temperature mushy layer, represented by ferrogranophyres, supports the possibility of a long-lived conduit subject to reopening after periods of quiescence in magmatic input, leading to the extrusion of the multiple flows of the Orange Mountain Basalt and perhaps even subsequent Preakness Basalt flows, depending on solidification conditions. A sub-Newark Basin network of sills subjected to similar protracted input of pulses as hypothesized for the Palisades was likely responsible for 600 ka of magmatic activity required to emplace a third set of Watchung flood basalts, the Hook Mountain Basalt.

Terrestrial rock glaciers: a potential analog for Martian lobate flow features (LFF)

NASA Astrophysics Data System (ADS)

Sinha, Rishitosh K.; Vijayan, Sivaprahasam; Bharti, Rajiv R.

2016-05-01

Rock glaciers, regarded as cryospheric ice/water resource in the terrestrial-glacial systems based on their tongue/lobate-shaped flow characteristic and subsurface investigation using ground-penetrating radar. We examined the subsurface, geomorphology, climate-sensitivity and thermophysical properties of a Lobate Flow Feature (LFF) on Mars (30°-60° N and S hemispheres) to compare/assess the potentials of rock glaciers as an analog in suggesting LFFs to be a source of subsurface ice/water. LFFs are generally observed at the foot of impact craters' wall. HiRISE/CTX imageries from MRO spacecraft were used for geomorphological investigation of LFF using ArcMap-10.0 and subsurface investigation was carried out using data from MRO-SHARAD (shallow radar) after integrating with SiesWare-8.0. ENVI-5.0 was used to retrieve thermophysical properties of LFF from nighttime datasets (12.57 μm) acquired by THEMIS instrument-onboard the Mars Odyssey spacecraft and derive LFFs morphometry from MOLA altimeter point tracks onboard MGS spacecraft. Integrating crater chronology tool (Craterstats) with Arc Map, we have derived the formation age of LFF. Our investigation and comparison of LFF to rock glaciers revealed: (1) LFFs have preserved ice at depth 50m as revealed from SHARAD radargram and top-layer composed of rocky-debris material with thermal inertia ( 300-350 Jm-2 K-1s-1/2). (2) LFF formation age ( 10-100 Ma) corresponds to moderate scale debris covered glaciation of a shorter-span suggesting high sensitivity to obliquity-driven climatic shifts. (3) Presence of polygon cracks and high linear-arcuate furrow-and-ridges on the surface indicates presence of buried ice. This work is a significant step towards suggesting LFF to be a potential source of present-day stored ice/water on Mars.

The eastern arm of the Midcontinent Rift: Progress and problems

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

Hinze, W.J.

1994-04-01

The extent and nature of the Midcontinent Rift System (MCR) was initially determined by potential-field mapping and extrapolation of geologic information from the Lake Superior region. Early interpretation suggested a rift origin which is well supported by deep crustal reflection seismic data and isotopic evidence from the related volcanic rocks that became available during the past decade. A rift origin of the eastern arm of the MCR was corroborated by sub-Phanerozoic drilling into the clastic sediment and volcanic rocks in the McClure-Sparks drill hole located on a massive anticlinal feature in the Precambrian rocks mapped by seismic reflection data. Subsequentmore » seismic profiling further detailed the character of the rift. However, these studies also indicate that the eastern arm is unlike the western, e.g., adjacent clastic rock basins are absent, late-stage compressional features are present, but definite evidence for high-angle reverse faulting is missing, and volcanic basins are not continuous. The termination of this arm of the rift also remains problematic. There is no direct evidence of the rift SE of the McClure-Sparks hole in central Michigan. Geophysical anomalies and deep drilling in the Howell anticline region suggest that the 1,100 Ma old rift is covered by Grenville-age thrusts. If the rift extends farther to the SE, its nature must have been altered by the Grenville orogeny. The hypothesized extension across Ohio east of the Grenville Front is unsupported by seismic reflection profiling and anomaly modeling. Grabens identified at the basement surface in Ohio and to the south are of unknown age, but appear to be more clearly related to late-stage Grenville activity and/or continuation of Eocambrian rifts of the Mississippi Embayment.« less

Space Weathering of Lunar Rocks

NASA Technical Reports Server (NTRS)

Noble, S. K.; Keller, L. P.; Christoffersen, R.; Rahman, Z.

2012-01-01

All materials exposed at the lunar surface undergo space weathering processes. On the Moon, boulders make up only a small percentage of the exposed surface, and areas where such rocks are exposed, like central peaks, are often among the least space weathered regions identified from remote sensing data. Yet space weathered surfaces (patina) are relatively common on returned rock samples, some of which directly sample the surface of larger boulders. Because, as witness plates to lunar space weathering, rocks and boulders experience longer exposure times compared to lunar soil grains, they allow us to develop a deeper perspective on the relative importance of various weathering processes as a function of time.

Geologic and hydrologic characterization and evaluation of the Basin and Range Province relative to the disposal of high-level radioactive waste: Part II, Geologic and hydrologic characterization

USGS Publications Warehouse

Sargent, Kenneth A.; Bedinger, M.S.

1985-01-01

The geology and hydrology of the Basin and Range Province of the western conterminous United States are characterized in a series of data sets depicted in maps compiled for evaluation of prospective areas for further study of geohydrologic environments for isolation of high-level radioactive waste. The data sets include: (1) Average precipitation and evaporation; (2) surface distribution of selected rock types; (3) tectonic conditions; and (4) surface- and ground -water hydrology and Pleistocene lakes and marshes.Rocks mapped for consideration as potential host media for the isolation of high-level radioactive waste are widespread and include argillaceous rocks, granitic rocks, tuffaceous rocks, mafic extrusive rocks, evaporites, and laharic breccias. The unsaturated zone, where probably as thick as 150 meters (500 feet), was mapped for consideration as an environment for isolation of high-level waste. Unsaturated rocks of various lithologic types are widespread in the Province.Tectonic stability in the Quaternary Period is considered the key to assessing the probability of future tectonism with regard to high-level radioactive waste disposal. Tectonic conditions are characterized on the basis of the seismic record, heat-flow measurements, the occurrence of Quaternary faults, vertical crustal movement, and volcanic features. Tectonic activity, as indicated by seismicity, is greatest in areas bordering the western margin of the Province in Nevada and southern California, the eastern margin of the Province bordering the Wasatch Mountains in Utah and in parts of the Rio Grande valley. Late Cenozoic volcanic activity is widespread, being greatest bordering the Sierra Nevada in California and Oregon, and bordering the Wasatch Mountains in southern Utah and Idaho.he arid to semiarid climate of the Province results in few perennial streams and lakes. A large part of the surface drainage is interior and the many closed basins commonly are occupied by playas or dry lake beds. The Province is divided into ground-water flow units defined on the basis of ground-water divides, ground-water flow lines, and surface streams that receive ground-water discharge.Ground water contains less than 500 milligrams per liter of dissolved solids throughout most of the Province. Ground water is more mineralized in areas underlain by evaporitic rocks, overlain by playas, and near saline lakes. Ground water is of the calcium, magnesium, or sodium bicarbonate type in the areas where dissolved-solids concentrations are less than 500 milligrams per liter, and of the calcium, magnesium, or sodium sulfate or chloride type where dissolved-solids concentrations are greater than 500 milligrams per liter.Geologic and hydrologic evidence is found for about 100 lakes and marshes that existed during the Pleistocene Epoch. The possibility of a recurrence of pluvial conditions, such as existed in the Pleistocene, is of concern in repository siting because of possible changes in hydrologic conditions. The Pleistocene lakes and marshes provide clues to the hydrology during pluvial climates.

7 CFR 1755.505 - Buried services.

Code of Federal Regulations, 2011 CFR

2011-01-01

... or cable to the surface of the ground or rock; (4) In the case of a layer of soil over rock either the minimum depth in rock measured to the surface of the rock, or the minimum depth in soil measured... cable shall be plowed or trenched to a depth of 12 in. (305 mm) or greater where practicable in soil, 36...

7 CFR 1755.505 - Buried services.

Code of Federal Regulations, 2014 CFR

2014-01-01

... or cable to the surface of the ground or rock; (4) In the case of a layer of soil over rock either the minimum depth in rock measured to the surface of the rock, or the minimum depth in soil measured... cable shall be plowed or trenched to a depth of 12 in. (305 mm) or greater where practicable in soil, 36...

7 CFR 1755.505 - Buried services.

Code of Federal Regulations, 2012 CFR

2012-01-01

... or cable to the surface of the ground or rock; (4) In the case of a layer of soil over rock either the minimum depth in rock measured to the surface of the rock, or the minimum depth in soil measured... cable shall be plowed or trenched to a depth of 12 in. (305 mm) or greater where practicable in soil, 36...

7 CFR 1755.505 - Buried services.

Code of Federal Regulations, 2013 CFR

2013-01-01

... or cable to the surface of the ground or rock; (4) In the case of a layer of soil over rock either the minimum depth in rock measured to the surface of the rock, or the minimum depth in soil measured... cable shall be plowed or trenched to a depth of 12 in. (305 mm) or greater where practicable in soil, 36...

Surface Changes in Chryse Planitia

NASA Technical Reports Server (NTRS)

1979-01-01

At the conclusion of the Viking Continuation Mission (May to November, 1978), all four cameras on the Viking Landers - two on each spacecraft - continued to function normally. During the two and one-half years since the landers touched down on Mars, images totaled 2,255 for Viking Lander 1 and 2,016 for Viking Lander 2. The surface around the landers was completely photographed by the end of 1976; subsequent images acquired during 1977-1978 have concentrated on searching for changes in the scene - changes which can be used to infer both the types of erosive processes which modify the landscape around the landers and the rates at which these processes may occur. The major surface changes have included the water-ice snow seen by Lander 2 during the winter at Utopia Planitia, and a thin dust layer deposited at both sites during the dust storms of 1977. The most recently identified change occurred at Chryse Planitia between VL-1 sols 767 (Sept. 16, 1978) and 771 (Sept. 20, 1978) as seen in the lower photo. Picture at top, selected to show similar lighting conditions, was taken during sol 25 (August 15, 1976). The change (A) appears as a small circle-like formation on the side of a drift in the lee, or downwind, side of Whale Rock. This is believed to have been a small-scale landslide of an unstable dust layer which had accumulated behind the rock. Interpretation of this feature would be difficult without an earlier change (B) near Big Joe, a slump which occurred between sols 74 and 183. The new slump is approximately 25- 35 meters from the lander, and just under a meter across. The slumping probably was initiated by the daily heating and cooling of the surface by solar radiation. More importantly, it is now believed that, based on the repeated occurrence of such slumping features, a dust layer which overlies the surface may in fact be redistributed fairly regularly during periods of high wind activity. There are no obvious indications of fossil slump features, therefore similar features must be destroyed on a regular basis. After the end of February, when Viking operations essentially terminate, Lander 1 will continue preselected observations over a period of possibly up to 10 years, following the instructions stored in its computer memory. Earth commands will be required only to initiate data transmission to Earth. During this time, it is now anticipated that one of the yearly planetwide global dust storms may reach an intensity necessary to shift the dust cover around the lander significantly.

Tsunamigenic earthquake simulations using experimentally derived friction laws

NASA Astrophysics Data System (ADS)

Murphy, S.; Di Toro, G.; Romano, F.; Scala, A.; Lorito, S.; Spagnuolo, E.; Aretusini, S.; Festa, G.; Piatanesi, A.; Nielsen, S.

2018-03-01

Seismological, tsunami and geodetic observations have shown that subduction zones are complex systems where the properties of earthquake rupture vary with depth as a result of different pre-stress and frictional conditions. A wealth of earthquakes of different sizes and different source features (e.g. rupture duration) can be generated in subduction zones, including tsunami earthquakes, some of which can produce extreme tsunamigenic events. Here, we offer a geological perspective principally accounting for depth-dependent frictional conditions, while adopting a simplified distribution of on-fault tectonic pre-stress. We combine a lithology-controlled, depth-dependent experimental friction law with 2D elastodynamic rupture simulations for a Tohoku-like subduction zone cross-section. Subduction zone fault rocks are dominantly incohesive and clay-rich near the surface, transitioning to cohesive and more crystalline at depth. By randomly shifting along fault dip the location of the high shear stress regions ("asperities"), moderate to great thrust earthquakes and tsunami earthquakes are produced that are quite consistent with seismological, geodetic, and tsunami observations. As an effect of depth-dependent friction in our model, slip is confined to the high stress asperity at depth; near the surface rupture is impeded by the rock-clay transition constraining slip to the clay-rich layer. However, when the high stress asperity is located in the clay-to-crystalline rock transition, great thrust earthquakes can be generated similar to the Mw 9 Tohoku (2011) earthquake.

Method and apparatus for measuring surface density of explosive and inert dust in stratified layers

DOEpatents

Sapko, Michael J.; Perlee, Henry E.

1988-01-01

A method for determining the surface density of coal dust on top of rock dust or rock dust on top of coal dust is disclosed which comprises directing a light source at either a coal or rock dust layer overlaying a substratum of the other, detecting the amount of light reflected from the deposit, generating a signal from the reflected light which is converted into a normalized output (V), and calculating the surface density from the normalized output. The surface density S.sub.c of coal dust on top of rock dust is calculated according to the equation: S.sub.c =1/-a.sub.c ln(V) wherein a.sub.c is a constant for the coal dust particles, and the surface density S.sub.r of rock dust on top of coal dust is determined by the equation: ##EQU1## wherein a.sub.r is a constant based on the properties of the rock dust particles. An apparatus is also disclosed for carrying out the method of the present invention.

Fractography applied to investigations of cores, outcrops, and fractured reservoirs

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

Kulander, B.

1995-11-01

Fractography focuses investigations on the topography of fracture surfaces. This topography is composed of fractographic features produced by changing stress magnitudes and directions along the advancing crack tip. Fractographic features commonly useful in core and outcrop analysis include the origin, twist hackle, inclusion hackle, and rib marks. These structures develop during brittle failure by Mode I loading at the crack tip and act together to form a hackle plume. Fractographic components throughout the plume record the dynamic history of fracture development. Components show, to the limit of visual scale, the principal stress directions, as well as relative stress magnitudes andmore » propagation velocities, that existed at the advancing fracture front. This information contributes to more meaningful conclusions in fracture investigations. In core studies, fractography aids identification of induced and natural fractures. Induced fractures and fractographic features show distinct geometry with that of the core and reflect the effects of the core boundary, in-situ stresses, drilling stresses, and rock anisotropies. Certain drilling- and coring-induced fractures possess orientations and fractographic features that suggest the direction of minimum in-situ stress and that this direction may change abruptly within the drilled volume of rock. Cored natural fractures generally originated away from the bit and possess fractographic features that bear no geometerical relationship to core parameters. Abrupt changes of natural fracture strike and development of twist hackle suggest locally complex paleostress distributions. A combined knowledge of in-situ stress and natural fracture trends is useful in predicting reservoir permeability. In outcrop, fractographic features, including abutting relationships between joints, more readily depict order of development, intrastratum distribution of fracturing stress, and size for joints in any set.« less

Rock pushing and sampling under rocks on Mars

USGS Publications Warehouse

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

1978-01-01

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

Stick-Shape, Rice-Size Features on Martian Rock "Haroldswick"

NASA Image and Video Library

2018-02-08

The dark, stick-shaped features clustered on this Martian rock are about the size of grains of rice. This is a focus-merged view from the Mars Hand Lens Imager (MAHLI) camera on NASA's Curiosity Mars rover. It covers an area about 2 inches (5 centimeters) across. The focus-merged product was generated autonomously by MAHLI combining the in-focus portions of a few separate images taken at different focus settings on Jan. 1, 2018, during the 1,922nd Martian day, or sol, of Curiosity's work on Mars. This rock target, called "Haroldswick," is near the southern, uphill edge of "Vera Rubin Ridge" on lower Mount Sharp. The origin of the stick-shaped features is uncertain. One possibility is that they are erosion-resistant bits of dark material from mineral veins cutting through rocks in this area. https://photojournal.jpl.nasa.gov/catalog/PIA22213

'They of the Great Rocks'

NASA Technical Reports Server (NTRS)

2004-01-01

This approximate true color image taken by the panoramic camera onboard the Mars Exploration Rover Spirit shows 'Adirondack,' the rover's first target rock. Spirit traversed the sandy martian terrain at Gusev Crater to arrive in front of the football-sized rock on Sunday, Jan. 18, 2004, just three days after it successfully rolled off the lander. The rock was selected as Spirit's first target because its dust-free, flat surface is ideally suited for grinding. Clean surfaces also are better for examining a rock's top coating. Scientists named the angular rock after the Adirondack mountain range in New York. The word Adirondack is Native American and means 'They of the great rocks.'

In search of the Abrams post office, Trinity County

USGS Publications Warehouse

Lanphere, Marvin A.; Irwin, William P.

1987-01-01

An understanding of earth history depends in part on stratigraphy, a division of geology in which the distinctive features of natural units or formations of layered rocks are studied and described and names are assigned to them. The procedures for describing and naming rock units in a uniform way are incorporated in documents known as stratigraphic codes. The North American Stratigraphic Code (1983) is currently used by most geologists in the United States when formation names are selected. Rock unit names consist of a geographic name, generally taken from a natural feature near the locality where the unit was first described, followed by a descriptive feature, usually the dominant rock type in the unit. Although the procedure for naming a rock unit seems straightforward, stratigraphic nomenclature can lead to confusion when the principles outlined in the stratigraphic code are ignored or incorrectly applied. This paper traces the naming of the Abrams Mica Schist, one of the major units of the northern California Klamath Mountains. It describes how uncertainty about the location of the geographic feature after which the unit was named has led to conflicting terminology. The search revealed some interesting history of the early days of mining in the Coffee Creek region of the Trinity Alps in Trinity County. 

Automatic extraction of planetary image features

NASA Technical Reports Server (NTRS)

LeMoigne-Stewart, Jacqueline J. (Inventor); Troglio, Giulia (Inventor); Benediktsson, Jon A. (Inventor); Serpico, Sebastiano B. (Inventor); Moser, Gabriele (Inventor)

2013-01-01

A method for the extraction of Lunar data and/or planetary features is provided. The feature extraction method can include one or more image processing techniques, including, but not limited to, a watershed segmentation and/or the generalized Hough Transform. According to some embodiments, the feature extraction method can include extracting features, such as, small rocks. According to some embodiments, small rocks can be extracted by applying a watershed segmentation algorithm to the Canny gradient. According to some embodiments, applying a watershed segmentation algorithm to the Canny gradient can allow regions that appear as close contours in the gradient to be segmented.

Surface properties of ancient cratered terrain in the northern hemisphere of Mars

NASA Technical Reports Server (NTRS)

Zimbelman, J. R.; Greeley, R.

1982-01-01

Viking high resolution IR data is used in an examination of the hilly and cratered material of Scott and Carr (1978), supposed to be the oldest extensively exposed surface on Mars. Measured nighttime temperatures at 11 and 20 microns indicate inertia blocks, surrounded by lower thermal inertia soil. Geologic features crossed by the Viking data generally show no difference from the regional properties. Imaging data from within and around the Arabia low thermal inertia region indicate that subdued surface morphology is not always associated with low thermal inertias. The mantling of ancient northern hemisphere cratered terrain by fine grained material does not allow thermal measurements to be directly related to rock unit properties, but less mantling may be present in southern hemisphere locations of this material.

Earth Observations taken by the Expedition 18 Crew

NASA Image and Video Library

2008-12-06

ISS018-E-011127 (6 Dec. 2008) --- Raven Ridge, Colorado is featured in this image photographed by an Expedition 18 crewmember on the International Space Station. An important way to unravel Earth?s history is to find and study old rocks that have been turned up and exposed on the surface through Earth?s tectonic activity. This image of Raven Ridge, Colorado provides a beautiful example of such a place that allows geologists to walk across rocks formed about 65 million years ago, now known as the ?K-T (or Cretaceous-Tertiary) Boundary?, according to scientists. The ridge is a dramatic topographic feature in northwestern Colorado formed by layered sedimentary rocks that span this boundary in geologic time. These sedimentary layers, originally deposited in a near-shore or marine environment as flat-lying beds, were later tilted on end to an almost vertical position by tectonic forces. The tilted beds are visible in this view as hard, resistant ridges of tan, buff, and white rocks, with a less resistant gray layer in the center of Raven Ridge (extending from left to right). The K-T Boundary is most famously known as the geological threshold where dinosaurs ? and a large number of other animal and plant species, both terrestrial and marine ? disappeared from the fossil record in a mass extinction event 66 ? 65 million years ago, according to scientists. Various hypotheses have been advanced to explain the mass extinction event - perhaps the best known being a large meteor impact that sparked widespread climate change or widespread volcanism that likewise produced significant climate change unfavorable for the existing plants and animals. The approximate location of the K-T Boundary is depicted in this image as a dotted white line ? rock layers to the south of the line belong to the Tertiary Period (lower half of image), while rocks to the north of the line are part of the Cretaceous and older Periods (upper half of image). A prominent topographic break in the ridgeline, Mormon Gap, provides road access across the Ridge. To the northwest of the Gap, several landslides formed in relatively soft Tertiary claystone, shale, and sandstone extend southwards from the crest of the Ridge.

Assessing More than a Decade of Alaska/yukon, High Elevation, Glacier Ice/rock Landslides

NASA Astrophysics Data System (ADS)

Molnia, B. F.; Angeli, K.

2017-12-01

On September 14, 2005, an estimated 5.0x106 m3 of rock, glacier ice, and snow fell from below the summit of 3,236-m-high Mt. Steller, Alaska, onto a tributary of Bering Glacier. Next day photography of the slide and source area suggested that meltwater played a significant role in its origin. Aerial photography and space-based electro-optical imagery collected for months following the event recorded continuing evidence of meltwater flowing from the head-scarp region and continued ice and snow melt. We investigated five similar glacier ice-rock landslides. These originated from the north face of Mt. Steller in late 2005-early 2006, the south side of Waxell Ridge in late 2005-early 2006, Mt. Steele on July 24, 2007, Mt. Lituya on June 11, 2012, and Mt. La Perouse on February 16, 2014. None was triggered by a seismic event. Four were detected based on seismic events they generated. All source areas exhibited failed hanging glaciers and/or failed perennial snowfields. Five had detectable glacier hydrologic features (moulins, conduits, and collapsed englacial stream channels) in near-summit failed ice and snow margins. Four displayed fresh concave bedrock failure surfaces. All originated at locations where mean annual temperatures were below freezing. Our observations support water triggering each event. We propose that abnormally warm summer temperatures or extreme winter precipitation produced unusual volumes of water which saturated summit snow and ice and/or filled summit glacier channels and conduits with liquid water. Water reached the frozen water/bedrock interface, destabilizing the contact. Fresh concave bedrock failure surfaces suggest that glacier beds were adhering to steep bedrock surfaces composed of a mélange of freeze/thaw shattered rock held together by interstitial ice. When the mass of saturated glacier ice failed, the bedrock mélange also failed, exposing fresh bedrock scarp depressions and generating the observed gravel-dominated slide debris.

Distal Ejecta from Lunar Impacts: Extensive Regions of Rocky Deposits

NASA Technical Reports Server (NTRS)

Bandfield, Joshua L.; Cahill, Joshua T. S.; Carter, Lynn M.; Neish, Catherine D.; Patterson, G. Wesley; Williams, Jean-Pierre; Paige, David A.

2016-01-01

Lunar Reconnaissance Orbiter (LRO) Diviner Radiometer, Mini-RF, and LRO Camera data were used to identify and characterize rocky lunar deposits that appear well separated from any potential source crater. Two regions are described: 1) A approximate 18,000 sq km area with elevated rock abundance and extensive melt ponds and veneers near the antipode of Tycho crater (167.5 deg E, 42.5 deg N). This region has been identified previously, using radar and aging data. 2) A much larger and more diffuse region, covering approximately 730,000 sq km, centered near 310 deg E, 35 deg S, containing elevated rock abundance and numerous granular flow deposits on crater walls. The rock distributions in both regions favor certain slope azimuths over others, indicating a directional component to the formation of these deposits. The spatial distribution of rocks is consistent with the arrival of ejecta from the west and northwest at low angles (approximately 10-30 deg) above the horizon in both regions. The derived age and slope orientations of the deposits indicate that the deposits likely originated as ejecta from the Tycho impact event. Despite their similar origin, the deposits in the two regions show significant differences in the datasets. The Tycho crater antipode deposit covers a smaller area, but the deposits are pervasive and appear to be dominated by impact melts. By contrast, the nearside deposits cover a much larger area and numerous granular flows were triggered. However, the features in this region are less prominent with no evidence for the presence of impact melts. The two regions appear to be surface expressions of a distant impact event that can modify surfaces across wide regions, resulting in a variety of surface morphologies. The Tycho impact event may only be the most recent manifestation of these processes, which likely have played a role in the development of the regolith throughout lunar history

Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation.

PubMed

Beaumont, C; Jamieson, R A; Nguyen, M H; Lee, B

2001-12-13

Recent interpretations of Himalayan-Tibetan tectonics have proposed that channel flow in the middle to lower crust can explain outward growth of the Tibetan plateau, and that ductile extrusion of high-grade metamorphic rocks between coeval normal- and thrust-sense shear zones can explain exhumation of the Greater Himalayan sequence. Here we use coupled thermal-mechanical numerical models to show that these two processes-channel flow and ductile extrusion-may be dynamically linked through the effects of surface denudation focused at the edge of a plateau that is underlain by low-viscosity material. Our models provide an internally self-consistent explanation for many observed features of the Himalayan-Tibetan system.

Rheology, tectonics, and the structure of the Venus lithosphere

NASA Technical Reports Server (NTRS)

Zuber, M. T.

1994-01-01

Given the absence of ground truth information on seismic structure, heat flow, and rock strength, or short wavelength gravity or magnetic data for Venus, information on the thermal, mechanical and compositional nature of the shallow interior must be obtained by indirect methods. Using pre-Magellan data, theoretical models constrained by the depths of impact craters and the length scales of tectonic features yielded estimates on the thickness of Venus' brittle-elastic lithosphere and the allowable range of crustal thickness and surface thermal gradient. The purpose of this study is to revisit the question of the shallow structure of Venus based on Magellan observations of the surface and recent experiments that address Venus' crustal rheology.

Database on unstable rock slopes in Norway

NASA Astrophysics Data System (ADS)

Oppikofer, Thierry; Nordahl, Bo; Bunkholt, Halvor; Nicolaisen, Magnus; Hermanns, Reginald L.; Böhme, Martina; Yugsi Molina, Freddy X.

2014-05-01

Several large rockslides have occurred in historic times in Norway causing many casualties. Most of these casualties are due to displacement waves triggered by a rock avalanche and affecting coast lines of entire lakes and fjords. The Geological Survey of Norway performs systematic mapping of unstable rock slopes in Norway and has detected up to now more than 230 unstable slopes with significant postglacial deformation. This systematic mapping aims to detect future rock avalanches before they occur. The registered unstable rock slopes are stored in a database on unstable rock slopes developed and maintained by the Geological Survey of Norway. The main aims of this database are (1) to serve as a national archive for unstable rock slopes in Norway; (2) to serve for data collection and storage during field mapping; (3) to provide decision-makers with hazard zones and other necessary information on unstable rock slopes for land-use planning and mitigation; and (4) to inform the public through an online map service. The database is organized hierarchically with a main point for each unstable rock slope to which several feature classes and tables are linked. This main point feature class includes several general attributes of the unstable rock slopes, such as site name, general and geological descriptions, executed works, recommendations, technical parameters (volume, lithology, mechanism and others), displacement rates, possible consequences, hazard and risk classification and so on. Feature classes and tables linked to the main feature class include the run-out area, the area effected by secondary effects, the hazard and risk classification, subareas and scenarios of an unstable rock slope, field observation points, displacement measurement stations, URL links for further documentation and references. The database on unstable rock slopes in Norway will be publicly consultable through the online map service on www.skrednett.no in 2014. Only publicly relevant parts of the database will be shown in the online map service (e.g. processed results of displacement measurements), while more detailed data will not (e.g. raw data of displacement measurements). Factsheets with key information on unstable rock slopes can be automatically generated and downloaded for each site, a municipality, a county or the entire country. Selected data will also be downloadable free of charge. The present database on unstable rock slopes in Norway will further evolve in the coming years as the systematic mapping conducted by the Geological Survey of Norway progresses and as available techniques and tools evolve.

Influence of specific surface area on coal dust explosibility using the 20-L chamber.

PubMed

Zlochower, Isaac A; Sapko, Michael J; Perera, Inoka E; Brown, Connor B; Harris, Marcia L; Rayyan, Naseem S

2018-07-01

The relationship between the explosion inerting effectiveness of rock dusts on coal dusts, as a function of the specific surface area (cm 2 /g) of each component is examined through the use of 20-L explosion chamber testing. More specifically, a linear relationship is demonstrated for the rock dust to coal dust (or incombustible to combustible) content of such inerted mixtures with the specific surface area of the coal and the inverse of that area of the rock dust. Hence, the inerting effectiveness, defined as above, is more generally linearly dependent on the ratio of the two surface areas. The focus on specific surface areas, particularly of the rock dust, provide supporting data for minimum surface area requirements in addition to the 70% less than 200 mesh requirement specified in 30 CFR 75.2.

Spirit's Express Route to 'Columbia Hills'

NASA Technical Reports Server (NTRS)

2004-01-01

This map illustrates the Mars Exploration Rover Spirit's position as of sol 112 (April 26, 2004), near the crater called 'Missoula.' Like a train on a tight schedule, Spirit will make regular stops along the way to its ultimate destination, the 'Columbia Hills.' At each stop, or 'station,' the rover will briefly analyze the area's rocks and soils. Each tick mark on the rover's route represents one sol's worth of travel, or about 60 to 70 meters (200 to 230 feet). Rover planners estimate that Spirit will reach the hills around mid-June. Presently, the rover is stopped at a site called 'Plains Station.'

The color thermal data show how well different surface features hold onto heat. Red indicates warmth; blue indicates coolness. Areas with higher temperatures are more likely to be rocky, as rocks absorb heat. Lower temperatures denote small particles and fewer rocks. During its traverse, Spirit will document the causes of these temperature variations.

The map comprises data from the camera on NASA's Mars Global Surveyor orbiter and the thermal emission imaging system on NASA's Mars Odyssey orbiter.

Mineral Potential in India Using Airborne Visible/Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG) Data

NASA Astrophysics Data System (ADS)

Oommen, T.; Chatterjee, S.

2017-12-01

NASA and the Indian Space Research Organization (ISRO) are generating Earth surface features data using Airborne Visible/Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG) within 380 to 2500 nm spectral range. This research focuses on the utilization of such data to better understand the mineral potential in India and to demonstrate the application of spectral data in rock type discrimination and mapping for mineral exploration by using automated mapping techniques. The primary focus area of this research is the Hutti-Maski greenstone belt, located in Karnataka, India. The AVIRIS-NG data was integrated with field analyzed data (laboratory scaled compositional analysis, mineralogy, and spectral library) to characterize minerals and rock types. An expert system was developed to produce mineral maps from AVIRIS-NG data automatically. The ground truth data from the study areas was obtained from the existing literature and collaborators from India. The Bayesian spectral unmixing algorithm was used in AVIRIS-NG data for endmember selection. The classification maps of the minerals and rock types were developed using support vector machine algorithm. The ground truth data was used to verify the mineral maps.

Structural Mapping Along the Central San Andreas Fault-zone Using Airborne Electromagnetics

NASA Astrophysics Data System (ADS)

Zamudio, K. D.; Bedrosian, P.; Ball, L. B.

2017-12-01

Investigations of active fault zones typically focus on either surface expressions or the associated seismogenic zones. However, the largely aseismic upper kilometer can hold significant insight into fault-zone architecture, strain partitioning, and fault-zone permeability. Geophysical imaging of the first kilometer provides a link between surface fault mapping and seismically-defined fault zones and is particularly important in geologically complex regions with limited surface exposure. Additionally, near surface imaging can provide insight into the impact of faulting on the hydrogeology of the critical zone. Airborne electromagnetic (AEM) methods offer a unique opportunity to collect a spatially-large, detailed dataset in a matter of days, and are used to constrain subsurface resistivity to depths of 500 meters or more. We present initial results from an AEM survey flown over a 60 kilometer long segment of the central San Andreas Fault (SAF). The survey is centered near Parkfield, California, the site of the SAFOD drillhole, which marks the transition between a creeping fault segment to the north and a locked zone to the south. Cross sections with a depth of investigation up to approximately 500 meters highlight the complex Tertiary and Mesozoic geology that is dismembered by the SAF system. Numerous fault-parallel structures are imaged across a more than 10 kilometer wide zone centered on the surface trace. Many of these features can be related to faults and folds within Plio-Miocene sedimentary rocks found on both sides of the fault. Northeast of the fault, rocks of the Mesozoic Franciscan and Great Valley complexes are extremely heterogeneous, with highly resistive volcanic rocks within a more conductive background. The upper 300 meters of a prominent fault-zone conductor, previously imaged to 1-3 kilometers depth by magnetotellurics, is restricted to a 20 kilometer long segment of the fault, but is up to 4 kilometers wide in places. Elevated fault-zone conductivity may be related to damage within the fault zone, Miocene marine shales, or some combination of the two.

Habitability from the Surface to the Deep

NASA Astrophysics Data System (ADS)

Cox, A. D.; Schmidt, R.; Dahlquist, G. R.; Foster, J.; Dillard, M.

2016-12-01

Merging aqueous geochemical parameters of habitability with microbial identity and activity will help determine microbial contributions to observed water-rock reactions in surface to deep environments. To determine habitability for microbial life and decipher mechanisms by which microbes survive and perform chemical reactions, over one hundred sites in diverse geological and geochemical environs have been sampled for aqueous geochemistry, mineralogy, and microbial identity and activity. Sites ranged from surficial creeks and rivers to the flooded mine shafts beneath to hydrothermal features in the caldera of a supervolcano 250 km distant; these environments contain metal scarcity, extreme anoxia, and wide variations in metal, organic carbon, and oxygen scarcity, respectively. Aqueous geochemistry included in situ measurement of temperature, pH, conductivity, and dissolved oxygen by meters; field spectrophotometry for redox active species; and synchronous sample collection and preservation for water isotopes, major cations and anions, trace elements, and dissolved inorganic and organic carbon, and more. Concurrent collection and preservation of planktonic and sediment biomass at each site will allow for microbial community identification and assessment of microbial activity. DNA extraction and PCR amplification using universal, eukaryotic, bacterial, and archaeal small subunit ribosomal RNA gene primers yielded products for sequencing. For many of the aqueous geochemical parameters analyzed, including Li and B, concentrations in flooded mine shafts fell on a continuum directly between local surface waters and those resulting from hydrothermal alteration suggesting an intermediate level of water-rock interaction in flooded mine shaft habitats. Concentrations of Li and B ranged from low micromolal in surface waters to millimolal in thermal waters. Other elements - Fe, Mn, Zn, and As included - were enriched in anoxic mine shafts by three to four orders of magnitude, due to exposure to and reaction with minerals. Concentrations of Fe and Zn ranged up to tens of millimolal whereas millimolal Mn and submillimolal As concentrations were reached. The transition from mostly unreacted surface water to waters nearly in equilibrium with rock provides vast geochemical habitat for microbes to exploit.

Verifying the new luminescence surface-exposure dating technique--rock falls in Canyonlands National Park, Utah

NASA Astrophysics Data System (ADS)

Pederson, J. L.; Sohbati, R.; Murray, A. S.; Jain, M.

2015-12-01

Recent studies have helped develop the optically stimulated luminescence (OSL) dating of rock surfaces, as applied to the age of the famous Great Gallery rock art panel in Canyonlands National Park. Chapot et al. (2012) dated a key rock fall to ~900 yrs ago by applying OSL to the outer 1-mm buried surface of a sandstone talus boulder, an age confirmed by independent radiocarbon dating. Later, in a novel approach and with the use of a local known-age calibration sample, Sohbati et al. (2012) modelled the millimeter-scale OSL-depth profile to determine a pre-burial exposure duration of ~700 years for the same rock fall. This combination of rock-fall dating and exposure dating--an approach with broad potential to date Holocene mass movements--constrains the creation of the Great Gallery rock art to a time window of 900 to ~1600 years ago (Pederson et al., 2014), a result met with some controversy. Here we report on a new phase of research to verify these results and further refine OSL-profile exposure dating for mass movements. New analyses from within and near the Great Gallery alcove include: i) exposure dating of the same alcove surface upon which the rock art is painted with a predicted exposure age of ~1600 years; ii) exposure dating of the top (light-exposed) side of the same rock-fall boulder whose buried side was previously dated to test for reproduction of the known age; and iii) an improved calibration sample from a nearby trail/road-cut for verification. The residual OSL signal is measured with depth in millimeter-thick increments of all samples. We first determine the site-specific luminescence reduction rate at the rock surface by fitting the OSL surface-exposure dating model to the calibration profile from the trail/road-cut. This parameterized model then provides exposure ages for the bleaching profiles observed in the other samples. Results have implications for the application of OSL rock-surface and exposure-profile dating in other settings where quartz-rich rock is available. We discuss how the light-exposed top and buried underside of clasts can be used in tandem for calibration. The technique has particular relevance to younger timescales over which cosmogenic nuclides are of limited application.

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

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

Traub, David; Nguyen, Jason

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

Hitherto unknown shear rupture mechanism as a source of instability in intact hard rocks at highly confined compression

NASA Astrophysics Data System (ADS)

Tarasov, Boris G.

2014-05-01

Today, frictional shear resistance along pre-existing faults is considered to be the lower limit on rock shear strength for confined conditions corresponding to the seismogenic layer. This paper introduces a recently identified shear rupture mechanism providing a paradoxical feature of hard rocks - the possibility of shear rupture propagation through the highly confined intact rock mass at shear stress levels significantly less than frictional strength. In the new mechanism, the rock failure associated with consecutive creation of small slabs (known as ‘domino-blocks') from the intact rock in the rupture tip is driven by a fan-shaped domino structure representing the rupture head. The fan-head combines such unique features as: extremely low shear resistance, self-sustaining stress intensification, and self-unbalancing conditions. Due to this the failure process caused by the mechanism is very dynamic and violent. This makes it impossible to directly observe and study the mechanism and can explain why the mechanism has not been detected before. This paper provides physical motivation for the mechanism, based upon side effects accompanying the failure process. Physical and mathematical models of the mechanism presented in the paper explain unique and paradoxical features of the mechanism. The new shear rupture mechanism allows a novel point of view for understanding the nature of spontaneous failure processes in hard rocks including earthquakes.

Formulations and algorithms for problems on rock mass and support deformation during mining

NASA Astrophysics Data System (ADS)

Seryakov, VM

2018-03-01

The analysis of problem formulations to calculate stress-strain state of mine support and surrounding rocks mass in rock mechanics shows that such formulations incompletely describe the mechanical features of joint deformation in the rock mass–support system. The present paper proposes an algorithm to take into account the actual conditions of rock mass and support interaction and the algorithm implementation method to ensure efficient calculation of stresses in rocks and support.

Pancam multispectral imaging results from the Spirit Rover at Gusev crater

USGS Publications Warehouse

Bell, J.F.; Squyres, S. W.; Arvidson, R. E.; Arneson, H.M.; Bass, D.; Blaney, D.; Cabrol, N.; Calvin, W.; Farmer, J.; Farrand, W. H.; Goetz, W.; Golombek, M.; Grant, J. A.; Greeley, R.; Guinness, E.; Hayes, A.G.; Hubbard, M.Y.H.; Herkenhoff, K. E.; Johnson, M.J.; Johnson, J. R.; Joseph, J.; Kinch, K.M.; Lemmon, M.T.; Li, R.; Madsen, M.B.; Maki, J.N.; Malin, M.; McCartney, E.; McLennan, S.; McSween, H.Y.; Ming, D. W.; Moersch, J.E.; Morris, R.V.; Dobrea, E.Z.N.; Parker, T.J.; Proton, J.; Rice, J. W.; Seelos, F.; Soderblom, J.; Soderblom, L.A.; Sohl-Dickstein, J. N.; Sullivan, R.J.; Wolff, M.J.; Wang, A.

2004-01-01

Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock regions exposed by brushing or grinding show near-infrared spectral signatures consistent with the presence of mafic silicates such as pyroxene or olivine. Atmospheric observations show a steady decline in dust opacity during the mission, and astronomical observations captured solar transits by the martian moons, Phobos and Deimos, as well as a view of Earth from the martian surface.

Pancam multispectral imaging results from the Spirit Rover at Gusev Crater.

PubMed

Bell, J F; Squyres, S W; Arvidson, R E; Arneson, H M; Bass, D; Blaney, D; Cabrol, N; Calvin, W; Farmer, J; Farrand, W H; Goetz, W; Golombek, M; Grant, J A; Greeley, R; Guinness, E; Hayes, A G; Hubbard, M Y H; Herkenhoff, K E; Johnson, M J; Johnson, J R; Joseph, J; Kinch, K M; Lemmon, M T; Li, R; Madsen, M B; Maki, J N; Malin, M; McCartney, E; McLennan, S; McSween, H Y; Ming, D W; Moersch, J E; Morris, R V; Dobrea, E Z Noe; Parker, T J; Proton, J; Rice, J W; Seelos, F; Soderblom, J; Soderblom, L A; Sohl-Dickstein, J N; Sullivan, R J; Wolff, M J; Wang, A

2004-08-06

Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock regions exposed by brushing or grinding show near-infrared spectral signatures consistent with the presence of mafic silicates such as pyroxene or olivine. Atmospheric observations show a steady decline in dust opacity during the mission, and astronomical observations captured solar transits by the martian moons, Phobos and Deimos, as well as a view of Earth from the martian surface.

Pancam multispectral imaging results from the Spirit Rover at Gusev Crater

NASA Technical Reports Server (NTRS)

Bell, J. F., III; Squyres, S. W.; Arvidson, R. E.; Arneson, H. M.; Bass, D.; Blaney, D.; Cabrol, N.; Calvin, W.; Farmer, J.; Farrand, W. H.;

Mass balance of a highly active rock glacier during the period 1954 and 2016

NASA Astrophysics Data System (ADS)

Kellerer-Pirklbauer, Andreas; Kaufmann, Viktor; Rieckh, Matthias

2017-04-01

Active rock glaciers are creep phenomena of permafrost in high-relief terrain moving slowly downwards and are often characterised by distinct flow structures with ridges and furrows. Active rock glaciers consist of ice and rock material. The ice component might be either congelation (refreezing of liquid water) or sedimentary ('glacier') ice whereas the rock material might be either of periglacial or glacial origin. The formation period of rock glaciers lasts for centuries to millennia as judged from relative or absolute dating approaches. The input of ice and debris onto the rock glacier mass transport system over such long periods might change substantially over time. Long-term monitoring of mass transport, mass changes and nourishment processes of rock glaciers are rare. In this study we analysed on a decadal-scale mass transport (based on photogrammetric and geodetic data; series 1969-2016), mass changes (geodetically-based mass balance quantification; series 1954-2012), and mass input (based on optical data from an automatic digital camera; series 2006-2016) onto the Hinteres Langtal Rock Glacier. This rock glacier is 900 m long, up to 300 m wide, covers an area of 0.17 km2 and is one of the most active ones in the Eastern European Alps. Mass transport rates at the surface indicate relatively low mean annual surface velocities until the beginning of this millennium. A first peak in the horizontal surface velocity was reached in 2003/04 followed by a period of deceleration until 2007/08. Afterwards the rates increased again substantially from year to year with maximum values in 2014/15 (exceeding 6 m/a). This increase in surface velocities during the last decades was accompanied by crevasse formation and landslide activities at its front. Mass changes show for all six analysed periods between 1954 and 2012 a clear negative surface elevation change with mean annual values ranging from -0.016 to -0.058 m/a. This implies a total volume decrease of -435,895 m3 (averaging to -7515 m3/a) over the 58-year period at the rock glacier system. The only area of substantial surface elevation gain was during all periods the rock glacier front indicating a rock glacier advance. Mass input onto the rock glacier transport system was assessed analysing 2044 terrestrial images taken automatically between September 2006 and August 2016 from the main rooting zone of the rock glacier. Results indicate that neither snow and ice nor rock material have been transported in large quantities to the rock glacier system during the 10 year monitoring period. Notable mass movement events have been detected only six times. Perennial snow patches in the rooting zone of the rock glacier only survived on average every second summer. We conclude that the rates of rock glacier mass transport and volumetric losses of the rock glacier are far higher than debris and ice input. This rock glacier is clearly in a state of detachment from its nourishment area and prone to starvation which will eventually lead to rock glacier inactivation. This is a feasible fate for many currently active rock glaciers in the European Alps.

Survival Times of Meter-Sized Rock Boulders on the Surface of Airless Bodies

NASA Technical Reports Server (NTRS)

Basilevsky, A. T.; Head, J. W.; Horz, F.; Ramsley, K.

2015-01-01

This study considers the survival times of meter-sized rock boulders on the surfaces of several airless bodies. As the starting point, we employ estimates of the survival times of such boulders on the surface of the Moon by[1], then discuss the role of destruction due to day-night temperature cycling, consider the meteorite bombardment environment on the considered bodies in terms of projectile flux and velocities and finally estimate the survival times. Survival times of meter-sized rocks on lunar surface: The survival times of hand specimen-sized rocks exposed to the lunar surface environment were estimated based on experiments modeling the destruction of rocks by meteorite impacts, combined with measurements of the lunar surface meteorite flux, (e.g.,[2]). For estimations of the survival times of meter-sized lunar boulders, [1] suggested a different approach based on analysis of the spatial density of boulders on the rims of small lunar craters of known absolute age. It was found that for a few million years, only a small fraction of the boulders ejected by cratering process are destroyed, for several tens of million years approx.50% are destroyed, and for 200-300 Ma, 90 to 99% are destroyed. Following [2] and other works, [1] considered that the rocks are mostly destroyed by meteorite impacts. Destruction of rocks by thermal-stress. However, high diurnal temperature variations on the surface of the Moon and other airless bodies imply that thermal stresses may also be a cause of surface rock destruction. Delbo et al. [3] interpreted the observed presence of fine debris on the surface of small asteroids as due to thermal surface cycling. They stated that because of the very low gravity on the surface of these bodies, ejecta from meteorite impacts should leave the body, so formation there of fine debris has to be due to thermal cycling. Based on experiments on heating-cooling of cm-scale pieces of ordinary and carbonaceous chondrites and theoretical modeling of expansion of the cracks formed they concluded that thermal fragmentation breaks up rocks larger than a few centimeters more quickly than do micrometeoroid impacts. According to them at 1 AU distance from the Sun the lifetime of 10 cm rock fragments on asteroids with a period of rotation from 2.2 to 6 hours should be only 103 to 104 years and the larger the rock the faster it gets destroyed. But although [3] are obviously correct stating that impact ejecta should leave small asteroids, the low-velocity part of escaping ejecta will mostly stay in orbits close this given asteroid and part of them will eventually return to it. Moreover, directly beneath the impact point the target rock should be fractured and crushed but may not leave the body (Figure 1). These two points question the conclusions of [3].

The Moon

NASA Astrophysics Data System (ADS)

Warren, P. H.

2003-12-01

Oxygen isotopic data suggest that there is a genetic relationship between the constituent matter of the Moon and Earth (Wiechert et al., 2001). Yet lunar materials are obviously different from those of the Earth. The Moon has no hydrosphere, virtually no atmosphere, and compared to the Earth, lunar materials uniformly show strong depletions of even mildly volatile constituents such as potassium, in addition to N2, O2, and H2O (e.g., Wolf and Anders, 1980). Oxygen fugacity is uniformly very low ( BVSP, 1981) and even the earliest lunar magmas seem to have been virtually anhydrous. These features have direct and far-reaching implications for mineralogical and geochemical processes. Basically, they imply that mineralogical diversity and thus variety of geochemical processes are subdued; a factor that to some extent offsets the comparative dearth of available data for lunar geochemistry.The Moon's gross physical characteristics play an important role in the more limited range of selenochemical compared to terrestrial geochemical processes. Although exceptionally large (radius=1,738 km) in relation to its parent planet, the Moon is only 0.012 times as massive as Earth. By terrestrial standards, pressures inside the Moon are feeble: the upper mantle gradient is 0.005 GPa km -1 (versus 0.033 GPa km -1 in Earth) and the central pressure is slightly less than 5 GPa. However, lunar interior pressures are sufficient to profoundly influence igneous processes (e.g., Warren and Wasson, 1979b; Longhi, 1992, 2002), and in this sense the Moon more resembles a planet than an asteroid.Another direct consequence of the Moon's comparatively small size was early, rapid decay of its internal heat engine. But the Moon's thermal disadvantage has resulted in one great advantage for planetology. Lunar surface terrains, and many of the rock samples acquired from them, retain for the most part characteristics acquired during the first few hundred million years of solar system existence. The Moon can thus provide crucial insight into the early development of the Earth, where the direct record of early evolution was effectively destroyed by billions of years of geological activity. Lunar samples show that the vast majority of the craters that pervade the Moon's surface are at least 3.9 Gyr old (Dalrymple and Ryder, 1996). Impact cratering has been a key influence on the geochemical evolution of the Moon, and especially the shallow Moon.The uppermost few meters of the lunar crust, from which all lunar samples are derived, is a layer of loose, highly porous, fine impact-generated debris - regolith or lunar "soil." Processes peculiar to the surface of an atmosphereless body, i.e., effects of exposure to solar wind, cosmic rays, and micrometeorite bombardment, plus spheroidal glasses formed by in-flight quenching of pyroclastic or impact-generated melt splashes, all are evident in any reasonably large sample of lunar soil (Lindsay, 1992; Keller and McKay, 1997; Eugster et al., 2000). The lunar regolith is conventionally envisaged as having a well-defined lower boundary, typically 5-10 m below the surface ( McKay et al., 1991); below the regolith is either (basically) intact rock, or else a somewhat vaguely defined "megaregolith" of loose but not so finely ground material. Ancient highland terrains tend to have a regolith roughly 2-3 times than that of the maria ( Taylor, 1982). However, in much of the highlands the regolith/megaregolith "boundary" may be gradational. The growth of a regolith can approach a steady-state thickness by shielding its substrate against further impacts ( Quaide and Oberbeck, 1975), but there is no reason to believe that the size-frequency spectrum of impactors bombarding the Moon ( Melosh, 1989; Neukum et al., 2001) features a discontinuity at whatever size (of order 1-10 m) would be necessary to limit disintegration to ˜10 m.All lunar samples are from the regolith, so the detailed provenance of any individual lunar sample is rarely obvious; and for ancient highland samples, never obvious. The closest approach toin situ sampling of bedrock came on the Apollo 15 mission. The regolith is very thin near the edge of the Hadley Rille, and many samples of clearly comagmatic basalts were acquired within meters of their 3.3 Ga "young," nearly intact, lava flow, so that their collective provenance is certain (Ryder and Cox, 1996). Even the regional provenance of any individual lunar sample is potentially allocthonous. However, most lunar rocks, even ancient highland rocks, are found within a few hundred kilometers of their original locations. This conclusion stems from theoretical modeling of cratered landscapes ( Shoemaker et al., 1970; Melosh, 1989), plus observational evidence such as the sharpness of geochemical boundaries between lava-flooded maria and adjacent highlands (e.g., Li and Mustard, 2000).Besides breaking up rock into loose debris, impacts create melt. Traces of melt along grain boundaries may suffice to produce new rock out of formerly loose debris; the resultant rock would be classified as either regolith breccia or fragmental breccia, depending upon whether surface fines were important, or not, respectively, in the precursor matter (Stöffler et al., 1980). Features diagnostic of a surface component include the presence of glass spherules (typically a mix of endogenous mare-pyroclastic glasses and impact-splash glasses) or abundant solar-wind-implanted noble gases (e.g., Eugster et al., 2000).Elsewhere, especially in the largest events in which a planet's gravitational strength limits displacement and the kinetic energy of impact is mainly partitioned into heat (Melosh, 1989), impact melt may constitute a major fraction of the volume of the material that becomes new rock. Rocks formed in this manner are classified as impact-melt breccias and subclassified based on whether they are clast-poor or clast-rich, and whether their matrix is crystalline or glassy ( Stöffler et al., 1980). Obvious lithic and mineral clasts are very common in impact-melt breccias, although the full initial proportion of clasts may not be evident in the final breccia. Some of the clasts may be so pulverized, especially in large impact events ( Schultz and Mendell, 1978), that they are "lost" by digestion into comingled superheated impact melt ( Simonds et al., 1976). By some definitions, the term impact-melt breccia may be applied to products of melt plus clast mixtures with initial melt proportion as low as 10 wt.% ( Simonds et al., 1976; Papike et al., 1998).A few impactites feature a recrystallized texture, i.e., they consist dominantly of a mosaic of grains meeting at ˜120° triple junctions. These metamorphic rocks, termed granulitic breccias, may form from various precursor igneous or impactite rocks, and the heat source may be regional (burial) or local, such as a nearby impact melt (Stöffler et al., 1980). But lunar granulitic breccias are almost invariably fine grained, and they tend to be "contaminated" with meteoritic siderophile elements (e.g., M. M. Lindstrom and D. J. Lindstrom, 1986; Warren et al., 1991; Cushing et al., 1999), implying that the precursor rocks were probably mostly shallow impact breccias (brecciation and siderophile-element contamination being concentrated near the surface), and the heat source was probably most often a proximal mass of impact melt.Besides impactites, which are predominant near the bombarded surface, virtually all other lunar crustal rocks are igneous or annealed-igneous. The super-arid Moon has never produced (by any conventional definition) sedimentary rock, and most assuredly has never hosted life. Even metamorphism is of reduced scope, with scant potential for fluid-driven metasomatism. Evidence for metamorphism among returned lunar samples is mostly confined to impact shock and thermal effects. Although regional burial metamorphism may occur (Stewart, 1975), deeply buried materials seldom find their way into the surface regolith, whence all samples come. Annealing of lunar rocks is more likely a product of simple postigneous slow cooling (at significant original depth), dry baking in proximity to an intrusion, or baking within a zone of impact heating.The Moon's repertoire of geochemical processes may seem limited, but it represents a key link between the sampled asteroids (see Chapters 1.05 and 1.11) and the terrestrial planets. Four billion years ago, at a time when all but monocrystalline bits of Earth's dynamic crust were fated for destruction, most of the Moon's crust had already achieved its final configuration. The Moon thus represents a unique window into the early thermal and geochemical state of a moderately large object that underwent igneous differentiation in the inner solar system, and into the cratering history of near-Earth space.

Soils and landforms from Fildes Peninsula and Ardley Island, Maritime Antarctica

NASA Astrophysics Data System (ADS)

Michel, Roberto F. M.; Schaefer, Carlos E. G. R.; López-Martínez, Jerónimo; Simas, Felipe N. B.; Haus, Nick W.; Serrano, Enrique; Bockheim, James G.

2014-11-01

Fildes Peninsula (F.P.) and Ardley Island (A.I.) are among the first ice-free areas in Maritime Antarctica. Since the last glacial retreat in this part of Antarctica (8000 to 5000 years BP), the landscape in these areas evolved under paraglacial to periglacial conditions, with pedogenesis marked by cryogenic processes. We carried out a detailed soil and geomorphology survey, with full morphological and analytical description for both areas; forty-eight soil profiles representing different landforms were sampled, analyzed and classified according to the U.S. Soil Taxonomy and the World Reference Base for Soil Resources (WRB). Soils are mostly turbic, moderately developed, with podzolization and strong phosphatization (chemical weathering of rock minerals and formation of amorphous Al and Fe minerals) in former ornithogenic sites while in areas with poor vegetation show typical features of cryogenic weathering. Nivation, solifluction, cryoturbation, frost weathering, ablation and surface erosion are widespread. The most represented landform system by surface in Fildes Peninsula is the periglacial one, and 15 different periglacial landforms types have been identified and mapped. These features occupy about 30% of the land surface, in which patterned ground and stone fields are the most common landforms. Other significant landforms as protalus lobes, rock glaciers or debris lobes indicate the extensive presence of permafrost. Soil variability was high, in terms of morphological, physical and chemical properties, due to varying lithic contributions and mixing of different rocks, as well as to different degrees of faunal influence. Three soil taxonomy orders were identified, whereas thirty four individual pedons were differentiated. Fildes Peninsula experiences a south-north gradient from periglacial to paraglacial conditions, and apparently younger soils and landforms are located close to the Collins Glacier. Arenosols/Entisols and Cryosols/Gelisols (frequently cryoturbic) are the most important soil classes; Leptosols/Entisols, Gleysols/Aquents and Cambisols/Inceptisols also occur, all with gelic properties, and with varying faunal influences. Both soil classification systems are adequate to distinguish the local pedogenesis processes. The WRB system is broader, since it was designed to be applied in all Polar Regions; the family classes adopted by the ST were effective in separating soils with important differences with regard to texture and gravel content, all important attributes accounting for the ecological succession and periglacial processes. An altitudinal organization of landforms and processes can be recognized from geomorphological mapping. Periglacial features are dominant above 50 m a.s.l. although are present at lower altitude.

Mechanical weathering and rock erosion by climate-dependent subcritical cracking

NASA Astrophysics Data System (ADS)

Eppes, Martha-Cary; Keanini, Russell

2017-06-01

This work constructs a fracture mechanics framework for conceptualizing mechanical rock breakdown and consequent regolith production and erosion on the surface of Earth and other terrestrial bodies. Here our analysis of fracture mechanics literature explicitly establishes for the first time that all mechanical weathering in most rock types likely progresses by climate-dependent subcritical cracking under virtually all Earth surface and near-surface environmental conditions. We substantiate and quantify this finding through development of physically based subcritical cracking and rock erosion models founded in well-vetted fracture mechanics and mechanical weathering, theory, and observation. The models show that subcritical cracking can culminate in significant rock fracture and erosion under commonly experienced environmental stress magnitudes that are significantly lower than rock critical strength. Our calculations also indicate that climate strongly influences subcritical cracking—and thus rock weathering rates—irrespective of the source of the stress (e.g., freezing, thermal cycling, and unloading). The climate dependence of subcritical cracking rates is due to the chemophysical processes acting to break bonds at crack tips experiencing these low stresses. We find that for any stress or combination of stresses lower than a rock's critical strength, linear increases in humidity lead to exponential acceleration of subcritical cracking and associated rock erosion. Our modeling also shows that these rates are sensitive to numerous other environment, rock, and mineral properties that are currently not well characterized. We propose that confining pressure from overlying soil or rock may serve to suppress subcritical cracking in near-surface environments. These results are applicable to all weathering processes.

Dissolution of salt on the east flank of the Permian Basin in the southwestern U.S.A.

USGS Publications Warehouse

Johnson, K.S.

1981-01-01

Hydrogeologic studies prove that natural dissolution of bedded salt occurs at shallow depths in many parts of the Permian Basin of the southwestern U.S.A. This is especially well-documented on the east side of the basin in study areas on the Cimarron River and Elm Fork in western Oklahoma, and on the Red River in the southeastern part of the Texas Panhandle. Four requirements for salt dissolution are: (1) a deposit of salt; (2) a supply of water unsaturated with respect to NaCl; (3) an outlet for removal of brine; and (4) energy to cause water to flow through the system. The supply of fresh groundwater in the region is recharged through permeable rocks, alluvium, terrace deposits, karstic features and fractures. Groundwater dissolves salt at depths of 10-250 m, and the resulting brine moves laterally and upward under hydrostatic pressure through caverns, fractures in disrupted rock, and clastic or carbonate aquifers until it reaches the land surface, where it forms salt plains and salt springs. In many areas, salt dissolution produces a self-perpetuating cycle: dissolution causes cavern development, followed by collapse and subsidence of overlying rock; then the resulting disrupted rock has a greater vertical permeability that allows increased water percolation and additional salt dissolution. ?? 1981.

'They of the Great Rocks'-2

NASA Technical Reports Server (NTRS)

2004-01-01

This approximate true color image taken by the panoramic camera onboard the Mars Exploration Rover Spirit shows 'Adirondack,' the rover's first target rock. Spirit traversed the sandy martian terrain at Gusev Crater to arrive in front of the football-sized rock on Sunday, Jan. 18, 2004, just three days after it successfully rolled off the lander. The rock was selected as Spirit's first target because its dust-free, flat surface is ideally suited for grinding. Clean surfaces also are better for examining a rock's top coating. Scientists named the angular rock after the Adirondack mountain range in New York. The word Adirondack is Native American and is interpreted by some to mean 'They of the great rocks.'

The PanCam instrument on the 2018 Exomars rover: Science Implementation Strategy and Integrated Surface Operations Concept

NASA Astrophysics Data System (ADS)

Schmitz, Nicole; Jaumann, Ralf; Coates, Andrew; Griffiths, Andrew; Hauber, Ernst; Trauthan, Frank; Paar, Gerhard; Barnes, Dave; Bauer, Arnold; Cousins, Claire

2010-05-01

Geologic context as a combination of orbital imaging and surface vision, including range, resolution, stereo, and multispectral imaging, is commonly regarded as basic requirement for remote robotic geology and forms the first tier of any multi-instrument strategy for investigating and eventually understanding the geology of a region from a robotic platform. Missions with objectives beyond a pure geologic survey, e.g. exobiology objectives, require goal-oriented operational procedures, where the iterative process of scientific observation, hypothesis, testing, and synthesis, performed via a sol-by-sol data exchange with a remote robot, is supported by a powerful vision system. Beyond allowing a thorough geological mapping of the surface (soil, rocks and outcrops) in 3D, using wide angle stereo imagery, such a system needs to be able to provide detailed visual information on targets of interest in high resolution, thereby enabling the selection of science targets and samples for further analysis with a specialized in-situ instrument suite. Surface vision for ESA's upcoming ExoMars rover will come from a dedicated Panoramic Camera System (PanCam). As integral part of the Pasteur payload package, the PanCam is designed to support the search for evidence of biological processes by obtaining wide angle multispectral stereoscopic panoramic images and high resolution RGB images from the mast of the rover [1]. The camera system will consist of two identical wide-angle cameras (WACs), which are arranged on a common pan-tilt mechanism, with a fixed stereo base length of 50 cm. The WACs are being complemented by a High Resolution Camera (HRC), mounted between the WACs, which allows a magnification of selected targets by a factor of ~8 with respect to the wide-angle optics. The high-resolution images together with the multispectral and stereo capabilities of the camera will be of unprecedented quality for the identification of water-related surface features (such as sedimentary rocks) and form one key to a successful implementation of ESA's multi-level strategy for the ExoMars Reference Surface Mission. A dedicated PanCam Science Implementation Strategy is under development, which connects the PanCam science objectives and needs of the ExoMars Surface Mission with the required investigations, planned measurement approach and sequence, and connected mission requirements. First step of this strategy is obtaining geological context to enable the decision where to send the rover. PanCam (in combination with Wisdom) will be used to obtain ground truth by a thorough geomorphologic mapping of the ExoMars rover's surroundings in near and far range in the form of (1) RGB or monochromatic full (i.e. 360°) or partial stereo panoramas for morphologic and textural information and stereo ranging, (2) mosaics or single images with partly or full multispectral coverage to assess the mineralogy of surface materials as well as their weathering state and possible past or present alteration processes and (3) small-scale high-resolution information on targets/features of interest, and distant or inaccessible sites. This general survey phase will lead to the identification of surface features like outcrops, ridges and troughs and the characterization of different rock and surface units based on their morphology, distribution, and spectral and physical properties. Evidence of water-bearing minerals, water-altered rocks or even water-lain sediments seen in the large-scale wide angle images will then allow for preselecting those targets/features considered relevant for detailed analysis and definition of their geologic context. Detailed characterization and, subsequently, selection of those preselected targets/features for further analysis will then be enabled by color high-resolution imagery, followed by the next tier of contact instruments to enable a decision on whether or not to acquire samples for further analysis. During the following drill/analysis phase, PanCam's High Resolution Camera will characterize the sample in the sample tray and observe the sample discharge into the Core Sample Transfer Mechanism. Key parts of this science strategy have been tested under laboratory conditions in two geology blind tests [2] and during two field test campaigns in Svalbard, using simulated mission conditions, an ExoMars representative Payload (ExoMars and MSL instrument breadboards), and Mars analog settings [3, 4]. The experiences gained are being translated into operational sequences, and, together with the science implementation strategy, form a first version of a PanCam Surface Operations plan. References: [1] Griffiths, A.D. et al. (2006) International Journal of Astrobiology 5 (3): 269-275, doi:10.1017/ S1473550406003387. [2] Pullan, D. et al. (2009) EPSC Abstracts, Vol. 4, EPSC2009-514. [3] Schmitz, N. et al. (2009) Geophysical Research Abstracts, Vol. 11, EGU2009-10621-2. [4] Cousins, C. et al. (2009) EPSC Abstracts, Vol. 4, EPSC2009-813.

Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

Treesearch

L. Liu; C.I. Millar; R.D. Westfall; H.A. Zebker

2013-01-01

Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at...

Geologic Map and Digital Data Base of the Almo Quadrangle and City of Rocks National Reserve, Cassia County, Idaho

USGS Publications Warehouse

Miller, David M.; Armstrong, Richard L.; Bedford, David R.; Davis, Marsha

2008-01-01

This geologic map describes the geology of the City of Rocks National Reserve and environs, located in the Albion Mountains of south-central Idaho. The most prominent geologic features of the Reserve are the spectacular rock spires that attracted visitors, beginning with commentary in the journals of travelers to California during the Gold Rush of 1849. The tectonic history is outlined, and descriptions of landscape processes, a newly discovered Quaternary fault, and features of the pinnacles are presented.

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.

'They of the Great Rocks'-3

NASA Technical Reports Server (NTRS)

2004-01-01

This 3-D perspective image taken by the panoramic camera onboard the Mars Exploration Rover Spirit shows 'Adirondack,' the rover's first target rock. Spirit traversed the sandy martian terrain at Gusev Crater to arrive in front of the football-sized rock on Sunday, Jan. 18, 2004, just three days after it successfully rolled off the lander. The rock was selected as Spirit's first target because it has a flat surface and is relatively free of dust - ideal conditions for grinding into the rock to expose fresh rock underneath. Clean surfaces also are better for examining a rock's top coating.Scientists named the angular rock after the Adirondack mountain range in New York. The word Adirondack is Native American and means 'They of the great rocks.' Data from the panoramic camera's red, green and blue filters were combined to create this approximate true color image.

Geochemistry of primary-carbonate bearing K-rich igneous rocks in the Awulale Mountains, western Tianshan: Implications for carbon-recycling in subduction zone

NASA Astrophysics Data System (ADS)

Yang, Wu-Bin; Niu, He-Cai; Shan, Qiang; Chen, Hua-Yong; Hollings, Pete; Li, Ning-Bo; Yan, Shuang; Zartman, Robert E.

2014-10-01

Arc magmatism plays an important role in the recycling of subducted carbon and returning it to the surface. However, the transfer mechanisms of carbon are poorly understood. In this study, the contribution of subducted carbonate-rich sediments to the genesis of the carbonate-bearing K-rich igneous rocks from western Tianshan was investigated. Four key triggers are involved, including sediments subduction, slab decarbonation, partial melting and magma segregation. The globular carbonate ocelli show C-O isotope signatures intermediate between oceanic sediments and mantle, suggesting that the carbon of the primary carbonate ocelli was derived from recycled subducted sediments in the mantle. Decarbonation of the subducted slab is regarded as the primary agent to carbonize the mantle wedge. Geochemical features indicate that the carbonate ocelli are primary, and that the parental K- and carbon-rich mafic alkaline magma was derived from partial melting of carbonated mantle wedge veined with phlogopite. Major and trace element compositions indicate that globular carbonate ocelli hosted in the Bugula K-rich igneous rocks are calcio-carbonate and formed primarily by segregation of the differentiated CO2-rich alkaline magma after crystallization fractionation. The K-rich alkaline magma, which formed from partial melting of metasomatized (i.e., phlogopite bearing) mantle wedge in the sub-arc region, is a favorable agent to transport subducted carbon back to the Earth's surface during carbon recycling in subduction zones, because of the high CO2 solubility in alkaline mafic magma. We therefore propose a model for the petrogenesis of the carbonate-bearing K-rich igneous rocks in western Tianshan, which are significant for revealing the mechanism of carbon recycling in subduction zones.

Surface denudation rate of gypsum in Sicily

NASA Astrophysics Data System (ADS)

Madonia, Giuliana; Vattano, Marco; Di Maggio, Cipriano; De Waele, Jo

2016-04-01

Studies on surface denudation rate of karst rocks were carried out for many years with different methods, although researches on limestones are much more numerous than those on gypsum. In Sicily the most large and complete Messinian evaporite succession of Gruppo Gessoso - Solfifero outcrops and since 1993-1994 surface denudation measurements were performed on different types of gypsum by the Micro-Erosion Meter (M.E.M.) method. MEM stations were placed on natural sites representing different lithological features of gypsum outcrops of the Island: 1) selenite gypsum with centimetre-sized crystals; 2) selenite gypsum with sub-centimetre crystals; 3) gypsum arenite; 4) microcrystalline gypsum; and 5) gypsum laminite (balatino type). The measuring stations are positioned in three localities in western and central Sicily: Santa Ninfa (Trapani), Ciminna (Palermo) and Campofranco (Caltanissetta). The average lowering rates vary in the different lithofacies: from 0.25 mm yr-1 in microcrystalline gypsum to 0.74 mm yr-1 in selenite gypsum with centimetre-sized crystals. The average surface denudation rates are 0.40 mm yr-1 in balatino gypsum and gypsum arenite, and 0.37 mm yr-1 in selenite gypsum with sub-centimetre crystals. These different values are connected to several factors such as: rock texture, dip of gypsum surfaces, climatic conditions, troubles on the measurement sites (e.g.: presence of lichens, soil, remains of vegetation, etc.). The aim of this paper is to show the results of roughly twenty years of experimental measurements, and to compare the surface denudation rate of gypsum in Sicily with those of other evaporite areas characterised by different climatic settings.

Wind streaks: geological and botanical effects on surface albedo contrast

NASA Astrophysics Data System (ADS)

Zimbelman, James R.; Williams, Steven H.

1996-09-01

Two wind streaks in the eastern Mojave Desert of California were examined to gain insight into the origin of the surface brightness contrast that makes them visible, both on the ground and in remote sensing data. The two localities are: a 4-km-long dark streak oriented S43E from the Amboy cinder cone (34°32'N, 115°46'W), located on a Quaternary basalt flow covered with aeolian sand, and a 2-km-long dark streak oriented S22E from a low hill near the southwestern base of Sleeping Beauty Mountain (34°48'N, 116°20'W), located on a sand-covered alluvial surface. In both cases, the dark streaks have enhanced rock abundances on the streak surface, relative to the surroundings. At the Amboy streak, slope wash likely contributed to the rock concentration on the streak surface, shielded from burial under aeolian sand by the cinder cone. At the Sleeping Beauty streak, the relative albedo contrast is strongly emphasized by the presence of Big Galleta grass only outside of the streak. The albedo contrast of the Sleeping Beauty streak can be effectively eliminated by the seasonal presence of annual grass preferentially within the streak. Some plants may have reflectances that are strongly dependent upon viewing and illumination geometry, raising the possibility that certain terrestrial aeolian features may appear variable on a diurnal basis. Alluvial processes appear to have been important at both localities for redistributing surface materials, even given the infrequent rain conditions present in the Mojave Desert.

Geomorphology of coal seam fires

NASA Astrophysics Data System (ADS)

Kuenzer, Claudia; Stracher, Glenn B.

2012-02-01

Coal fires occur in underground natural coal seams, in exposed surface seams, and in coal storage or waste piles. The fires ignite through spontaneous combustion or natural or anthropogenic causes. They are reported from China, India, USA, South Africa, Australia, and Russia, as well as many other countries. Coal fires lead to loss of a valuable resource (coal), the emission of greenhouse-relevant and toxic gases, and vegetation deterioration. A dangerous aspect of the fires is the threat to local mines, industries, and settlements through the volume loss underground. Surface collapse in coal fire areas is common. Thus, coal fires are significantly affecting the evolution of the landscape. Based on more than a decade of experience with in situ mapping of coal fire areas worldwide, a general classification system for coal fires is presented. Furthermore, coal seam fire geomorphology is explained in detail. The major landforms associated with, and induced by, these fires are presented. The landforms include manifestations resulting from bedrock surface fracturing, such as fissures, cracks, funnels, vents, and sponges. Further manifestations resulting from surface bedrock subsidence include sinkholes, trenches, depressions, partial surface subsidence, large surface subsidence, and slides. Additional geomorphologic coal fire manifestations include exposed ash layers, pyrometamorphic rocks, and fumarolic minerals. The origin, evolution, and possible future development of these features are explained, and examples from in situ surveys, as well as from high-resolution satellite data analyses, are presented. The geomorphology of coal fires has not been presented in a systematic manner. Knowledge of coal fire geomorphology enables the detection of underground coal fires based on distinct surface manifestations. Furthermore, it allows judgments about the safety of coal fire-affected terrain. Additionally, geomorphologic features are indicators of the burning stage of fires. Finally, coal fire geomorphology helps to explain landscape features whose occurrence would otherwise not be understood. Although coal fire-induced thermal anomalies and gas release are also indications of coal fire activity, as addressed by many investigators, no assessment is complete without sound geomorphologic mapping of the fire-induced geomorphologic features.

On the interaction between ocean surface waves and seamounts

NASA Astrophysics Data System (ADS)

Sosa, Jeison; Cavaleri, Luigi; Portilla-Yandún, Jesús

2017-12-01

Of the many topographic features, more specifically seamounts, that are ubiquitous in the ocean floor, we focus our attention on those with relatively shallow summits that can interact with wind-generated surface waves. Among these, especially relatively long waves crossing the oceans (swells) and stormy seas are able to affect the water column up to a considerable depth and therefore interact with these deep-sea features. We quantify this interaction through numerical experiments using a numerical wave model (SWAN), in which a simply shaped seamount is exposed to waves of different length. The results show a strong interaction that leads to significant changes in the wave field, creating wake zones and regions of large wave amplification. This is then exemplified in a practical case where we analyze the interaction of more realistic sea conditions with a very shallow rock in the Yellow Sea. Potentially important for navigation and erosion processes, mutatis mutandis, these results are also indicative of possible interactions with emerged islands and sand banks in shelf seas.

Structural controls on the large landslides triggered by the 14 November 2016, MW 7.8 Earthquake, Kaikoura, New Zealand

NASA Astrophysics Data System (ADS)

Massey, Chris

2017-04-01

The Kaikoura earthquake generated tens of thousands of landslides over a total area of about 10,000 km2, with the majority concentrated in a smaller area of about 3,500 km2. A noteworthy aspect of this event is the large number of landslides that occurred on the steep coastal cliffs south of Ward and extending to Oaro, north of Christchurch, which led to the closure of state highway routes. Another noteworthy feature of this earthquake is the large number (more than 190) of valley blocking landslides it generated. This was partly due to the presence of steep and confined slopes in areas of strong ground shaking. The largest valley blocking landslide has an approximate volume of 12(±2) M m3 and the debris travelled about 2.7 km down slope forming a dam on the Hapuku River. Given the sparse population in the vicinity of the landslides, only a few homes were impacted and there were no recorded deaths due to landslides. However, the long-term stability of cracked slopes and landslide "dams" from future strong earthquakes and significant rain events are an ongoing concern to central and local government agencies responsible for rebuilding homes and infrastructure. A particular concern is the potential for debris floods to affect downstream residences and infrastructure should some of the landslide dams breach catastrophically. The mapped landslide distribution reflects the complexity of the earthquake rupture—at least 13 faults ruptured to the ground surface or sea floor. The majority of landslides occurred in two geological and geotechnically distinct materials: Neogene sedimentary rocks (sandstones, limestones and siltstones) where first-time and reactivated rock-slides were the dominant landslide type, and Torlesse "basement" rocks (greywacke sandstones and argillite) where first-time rock and debris avalanches dominated. The largest landslides triggered by the earthquake are located either on or adjacent to faults that ruptured to the ground surface and so they are distributed across a wide area, and most have slide surfaces that correspond to geological discontinuities. Initial results from our landslide investigations suggest: predictive models relying only on ground-shaking estimates may underestimate the number and size of the larger landslides that occurred, surface faults may provide a plane of weakness or hydrological discontinuity, and adversely oriented surface faults may be indicative of the location of future large landslides.

Are There High Meteorite Concentrations in the Atacama Desert/Chile?

NASA Astrophysics Data System (ADS)

Scherer, P.; Delisle, G.

1992-07-01

We have visited numerous regions of the Atacama desert between Copiapo (27 degrees, 15'S) and Calama (22 degrees, 25'S) to assess their potential as a high-yield meteorite concentration surface, easily exploitable by search efforts within a reasonable time frame. According to our observations, this desert is characterized by the following features: a) A high percentage of the desert consists of sloping surfaces on which soil movement occurs, presumably by very infrequent, though heavy rain. b) Vast areas of the desert are covered by a dm-thick sand layer of dark colour. Since the sand is too coarse-grained to be transported by wind it presumably resulted from in-situ weathering of rock debris derived from nearby mountains. We suspect that impacting smaller objects can easily penetrate the sand layer. c) The sand layer is typically dotted by rocks, fist-size or smaller, that are covered by a thick layer of desert paint (reddish-brown to black colour). Most country rocks are of volcanic origin (rhyolite, andesite, basalt) and are typically of grey to black colour. A noticeable colour contrast in particular to potential stony meteorites is almost nonexistent. d) Soil salts with a potential to speed up weathering processes are ubiquitous near the surface. e) The Pampa de Mejillones, 45 km north of Antofagasta, is one of the few light-coloured areas in the Atacama desert. The surface, being of Mio-Pliocene age, consists of an almost continuous layer of light-brown fossil shells (bivalves and gastropodes). Fluvially transported dark rocks from adjacent outcrops rest on top. The latter material is covered again by desert paint. Few meteorite discoveries have been reported from this area (Pampa (a),(b),(c)). f) Numerous old tire tracks, in particular around mines in operation, crisscross most areas of the Atacama. Undetected objects such as large masses of iron bodies are not likely to have remained undiscovered in great numbers any more. We conclude that the potential of the Atacama desert for a successful meteorite search is rather low in comparison to other deserts such as the Nullarbor Plain, Australia (Bevan and Binns, 1989), or the Acfer region, Algeria (Otto, 1992). We will demonstrate the vastly different surface conditions of areas with meteorite concentrations from these three localities. References: Bevan A.W.R. and Binns R.A. (1989) Meteoritics 24, 127. Otto J. (1992) Chem. Erde 52, 33.

Hawaiian submarine manganese-iron oxide crusts - A dating tool?

USGS Publications Warehouse

Moore, J.G.; Clague, D.A.

2004-01-01

Black manganese-iron oxide crusts form on most exposed rock on the ocean floor. Such crusts are well developed on the steep lava slopes of the Hawaiian Ridge and have been sampled during dredging and submersible dives. The crusts also occur on fragments detached from bedrock by mass wasting, on submerged coral reefs, and on poorly lithified sedimentary rocks. The thickness of the crusts was measured on samples collected since 1965 on the Hawaiian Ridge from 140 dive or dredge localities. Fifty-nine (42%) of the sites were collected in 2001 by remotely operated vehicles (ROVs). The thinner crusts on many samples apparently result from post-depositional breakage, landsliding, and intermittent burial of outcrops by sediment. The maximum crust thickness was selected from each dredge or dive site to best represent crusts on the original rock surface at that site. The measurements show an irregular progressive thickening of the crusts toward the northwest-i.e., progressive thickening toward the older volcanic features with increasing distance from the Hawaiian hotspot. Comparison of the maximum crust thickness with radiometric ages of related subaerial features supports previous studies that indicate a crust-growth rate of about 2.5 mm/m.y. The thickness information not only allows a comparison of the relative exposure ages of two or more features offshore from different volcanoes, but also provides specific age estimates of volcanic and landslide deposits. The data indicate that some of the landslide blocks within the south Kona landslide are the oldest exposed rock on Mauna Loa, Kilauea, or Loihi volcanoes. Crusts on the floors of submarine canyons off Kohala and East Molokai volcanoes indicate that these canyons are no longer serving as channelways for downslope, sediment-laden currents. Mahukona volcano was approximately synchronous with Hilo Ridge, both being younger than Hana Ridge. The Nuuanu landslide is considerably older than the Wailau landslide. The Waianae landslide southwest of Oahu has yielded samples with the greatest manganese-iron oxide crusts (9.5 mm thick) and therefore apparently represents the oldest submarine material yet found in the study area. The submarine volcanic field 100 km southwest of Oahu is apparently younger than the Waianae landslide. ?? 2004 Geological Society of America.

Rippled scour depressions on the inner continental shelf off central California

USGS Publications Warehouse

Cacchione, David A.; Drake, David E.; Grant, William D.; Tate, George B.

1984-01-01

Side-scan sonar records taken during the recent Coastal Ocean Dynamics Experiment (CODE) show elongate, shore-normal tippled depressions of low relief on the inner continental shelf off central California between Bodega Bay and Point Arena. These features extend up to 2 kin from the coast into water depths of up to 65 m. The proposed mechanism for their generation is storm- generated bottom currents associated with coastal downwelling during the late fall and winter which scour the surficial fine-sand sediment and expose the coarser-sand substrate in the depressions. The zones of most intense erosion and the irregular spacing of the features may be controlled by submerged rock ledges and other prominent coastal features. The large straight-crested ripples within the depres- sions (heights to 40 cm; wavelengths to 1.7 m) are probably formed by large-amplitude, long-period surface waves generated by winter storms.

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

DOEpatents

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

2015-08-18

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

Secondary Fracturing of Europa's Crust in Response to Combined Slip and Dilation Along Strike-Slip Faults

NASA Technical Reports Server (NTRS)

Kattenhorn, S. A.

2003-01-01

A commonly observed feature in faulted terrestrial rocks is the occurrence of secondary fractures alongside faults. Depending on exact morphology, such fractures have been termed tail cracks, wing cracks, kinks, or horsetail fractures, and typically form at the tip of a slipping fault or around small jogs or steps along a fault surface. The location and orientation of secondary fracturing with respect to the fault plane or the fault tip can be used to determine if fault motion is left-lateral or right-lateral.

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

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

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

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

Water soluble cations and the fluvial history of Mars

NASA Technical Reports Server (NTRS)

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

1975-01-01

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

Hydromechanical coupling in fractured rock masses: mechanisms and processes of selected case studies

NASA Astrophysics Data System (ADS)

Zangerl, Christian

2015-04-01

Hydromechanical (HM) coupling in fractured rock play an important role when events including dam failures, landslides, surface subsidences due to water withdrawal or drainage, injection-induced earthquakes and others are analysed. Generally, hydromechanical coupling occurs when a rock mass contain interconnected pores and fractures which are filled with water and pore/fracture pressures evolves. In the on hand changes in the fluid pressure can lead to stress changes, deformations and failures of the rock mass. In the other hand rock mass stress changes and deformations can alter the hydraulic properties and fluid pressures of the rock mass. Herein well documented case studies focussing on surface subsidence due to water withdrawal, reversible deformations of large-scale valley flanks and failure as well as deformation processes of deep-seated rock slides in fractured rock masses are presented. Due to pore pressure variations HM coupling can lead to predominantly reversible rock mass deformations. Such processes can be considered by the theory of poroelasticity. Surface subsidence reaching magnitudes of few centimetres and are caused by water drainage into deep tunnels are phenomenas which can be assigned to processes of poroelasticity. Recently, particular focus was given on large tunnelling projects to monitor and predict surface subsidence in fractured rock mass in oder to avoid damage of surface structures such as dams of large reservoirs. It was found that surface subsidence due to tunnel drainage can adversely effect infrastructure when pore pressure drawdown is sufficiently large and spatially extended and differential displacements which can be amplified due to topographical effects e.g. valley closure are occurring. Reversible surface deformations were also ascertained on large mountain slopes and summits with the help of precise deformation measurements i.e. permanent GPS or episodic levelling/tacheometric methods. These reversible deformations are often in the range of millimetres to a very few centimetres and can be linked to annual groundwater fluctuations. Due to pore pressure variations HM coupling can influence seepage forces and effective stresses in the rock mass. Effective stress changes can adversely affect the stability and deformation behaviour of deep-seated rock slides by influencing the shear strength or the time dependent (viscous) material behaviour of the basal shear zone. The shear strength of active shear zones is often reasonably well described by Coulomb's law. In Coulomb's law the operative normal stresses to the shear surface/zone are effective stresses and hence pore pressures which should be taken into account reduces the shear strength. According to the time dependent material behaviour a few effective stress based viscous models exists which are able to consider pore pressures. For slowly moving rock slides HM coupling could be highly relevant when low-permeability clayey-silty shear zones (fault gouges) are existing. An important parameters therefore is the hydraulic diffusivity, which is controlled by the permeability and fluid-pore compressibility of the shear zone, and by fluid viscosity. Thus time dependent pore pressure diffusion in the shear zone can either control the stability condition or the viscous behaviour (creep) of the rock slide. Numerous cases studies show that HM coupling can effect deformability, shear strength and time dependent behaviour of fractured rock masses. A process-based consideration can be important to avoid unexpected impacts on infrastructures and to understand complex rock mass as well rock slide behaviour.

Opportunity Takes a Last Look at Rock Exposure Before Heading to Victoria Crater

NASA Image and Video Library

2006-08-24

This true-color image shows a circular indentation in a flat-topped rock surface. Around the edge of the hole is a fine layer of dust. The rock has a moderately cracked the surface. Around it is a layer of sand and pebbles. The view is reddish brown

Estimation of Confined Peak Strength of Crack-Damaged Rocks

NASA Astrophysics Data System (ADS)

Bahrani, Navid; Kaiser, Peter K.

2017-02-01

It is known that the unconfined compressive strength of rock decreases with increasing density of geological features such as micro-cracks, fractures, and veins both at the laboratory specimen and rock block scales. This article deals with the confined peak strength of laboratory-scale rock specimens containing grain-scale strength dominating features such as micro-cracks. A grain-based distinct element model, whereby the rock is simulated with grains that are allowed to deform and break, is used to investigate the influence of the density of cracks on the rock strength under unconfined and confined conditions. A grain-based specimen calibrated to the unconfined and confined strengths of intact and heat-treated Wombeyan marble is used to simulate rock specimens with varying crack densities. It is demonstrated how such cracks affect the peak strength, stress-strain curve and failure mode with increasing confinement. The results of numerical simulations in terms of unconfined and confined peak strengths are used to develop semi-empirical relations that relate the difference in strength between the intact and crack-damaged rocks to the confining pressure. It is shown how these relations can be used to estimate the confined peak strength of a rock with micro-cracks when the unconfined and confined strengths of the intact rock and the unconfined strength of the crack-damaged rock are known. This approach for estimating the confined strength of crack-damaged rock specimens, called strength degradation approach, is then verified by application to published laboratory triaxial test data.

Sedimentary rock-hosted Au deposits of the Dian-Qian-Gui area, Guizhou, and Yunnan Provinces, and Guangxi District, China

USGS Publications Warehouse

Peters, S.G.; Jiazhan, H.; Zhiping, L.; Chenggui, J.

2007-01-01

Sedimentary rock-hosted Au deposits in the Dian-Qian-Gui area in southwest China are hosted in Paleozoic and early Mesozoic sedimentary rocks along the southwest margin of the Yangtze (South China) Precambrian craton. Most deposits have characteristics similar to Carlin-type Au deposits and are spatially associated, on a regional scale, with deposits of coal, Sb, barite, As, Tl, and Hg. Sedimentary rock-hosted Au deposits are disseminated stratabound and(or) structurally controlled. The deposits have many similar characteristics, particularly mineralogy, geochemistry, host rock, and structural control. Most deposits are associated with structural domes, stratabound breccia bodies, unconformity surfaces or intense brittle-ductile deformation zones, such as the Youjiang fault system. Typical characteristics include impure carbonate rock or calcareous and carbonaceous host rock that contains disseminated pyrite, marcasite, and arsenopyrite-usually with ??m-sized Au, commonly in As-rich rims of pyrite and in disseminations. Late realgar, orpiment, stibnite, and Hg minerals are spatially associated with earlier forming sulfide minerals. Minor base-metal sulfides, such as galena, sphalerite, chalcopyrite, and Pb-Sb-As-sulphosalts also are present. The rocks locally are silicified and altered to sericite-clay (illite). Rocks and(or) stream-sediment geochemical signatures typically include elevated concentrations of As, Sb, Hg, Tl, and Ba. A general lack of igneous rocks in the Dian-Qian-Gui area implies non-pluton-related, ore forming processes. Some deposits contain evidence that sources of the metal may have originated in carbonaceous parts of the sedimentary pile or other sedimentary or volcanic horizons. This genetic process may be associated with formation and mobilization of petroleum and Hg in the region and may also be related to As-, Au-, and Tl-bearing coal horizons. Many deposits also contain textures and features indicative of strong structural control by tectonic domes or shear zones and also suggest syndeformational ore deposition, possibly related to the Youjiang fault system. Several sedimentary rock-hosted Au deposits in the Dian-Qian-Gui area also are of the red earth-type and Au grades have been concentrated and enhanced during episodes of deep weathering. ?? 2006 Elsevier B.V. All rights reserved.

Mineral Surface Rearrangement at High Temperatures: Implications for Extraterrestrial Mineral Grain Reactivity.

PubMed

King, Helen E; Plümper, Oliver; Putnis, Christine V; O'Neill, Hugh St C; Klemme, Stephan; Putnis, Andrew

2017-04-20

Mineral surfaces play a critical role in the solar nebula as a catalytic surface for chemical reactions and potentially acted as a source of water during Earth's accretion by the adsorption of water molecules to the surface of interplanetary dust particles. However, nothing is known about how mineral surfaces respond to short-lived thermal fluctuations that are below the melting temperature of the mineral. Here we show that mineral surfaces react and rearrange within minutes to changes in their local environment despite being far below their melting temperature. Polished surfaces of the rock and planetary dust-forming silicate mineral olivine ((Mg,Fe) 2 SiO 4 ) show significant surface reorganization textures upon rapid heating resulting in surface features up to 40 nm in height observed after annealing at 1200 °C. Thus, high-temperature fluctuations should provide new and highly reactive sites for chemical reactions on nebula mineral particles. Our results also may help to explain discrepancies between short and long diffusion profiles in experiments where diffusion length scales are of the order of 100 nm or less.

Rock discontinuity surface roughness variation with scale

NASA Astrophysics Data System (ADS)

Bitenc, Maja; Kieffer, D. Scott; Khoshelham, Kourosh

2017-04-01

ABSTRACT: Rock discontinuity surface roughness refers to local departures of the discontinuity surface from planarity and is an important factor influencing the shear resistance. In practice, the Joint Roughness Coefficient (JRC) roughness parameter is commonly relied upon and input to a shear strength criterion such as developed by Barton and Choubey [1977]. The estimation of roughness by JRC is hindered firstly by the subjective nature of visually comparing the joint profile to the ten standard profiles. Secondly, when correlating the standard JRC values and other objective measures of roughness, the roughness idealization is limited to a 2D profile of 10 cm length. With the advance of measuring technologies that provide accurate and high resolution 3D data of surface topography on different scales, new 3D roughness parameters have been developed. A desirable parameter is one that describes rock surface geometry as well as the direction and scale dependency of roughness. In this research a 3D roughness parameter developed by Grasselli [2001] and adapted by Tatone and Grasselli [2009] is adopted. It characterizes surface topography as the cumulative distribution of local apparent inclination of asperities with respect to the shear strength (analysis) direction. Thus, the 3D roughness parameter describes the roughness amplitude and anisotropy (direction dependency), but does not capture the scale properties. In different studies the roughness scale-dependency has been attributed to data resolution or size of the surface joint (see a summary of researches in [Tatone and Grasselli, 2012]). Clearly, the lower resolution results in lower roughness. On the other hand, have the investigations of surface size effect produced conflicting results. While some studies have shown a decrease in roughness with increasing discontinuity size (negative scale effect), others have shown the existence of positive scale effects, or both positive and negative scale effects. We hypothesize that roughness can increase or decrease with the joint size, depending on the large scale roughness (or waviness), which is entering the roughness calculation once the discontinuity size increases. Therefore, our objective is to characterize roughness at various spatial scales, rather than at changing surface size. Firstly, the rock surface is interpolated into a grid on which a Discrete Wavelet Transform (DWT) is applied. The resulting surface components have different frequencies, or in other words, they have a certain physical scale depending on the decomposition level and input grid resolution. Secondly, the Grasselli Parameter is computed for the original and each decomposed surface. Finally, the relative roughness change is analyzed with respect to increasing roughness wavelength for four different rock samples. The scale variation depends on the sample itself and thus indicates its potential mechanical behavior. References: - Barton, N. and V. Choubey (1977). "The shear strength of rock joints in theory and practice." Rock Mechanics and Rock Engineering 10(1): 1-54. - Grasselli, G. (2001). Shear strength of rock joints based on quantified surface description. École Polytechnique Fédérale de Lausanne. Lausanne, EPFL. - Tatone, B. S. A. and G. Grasselli (2009). "A method to evaluate the three-dimensional roughness of fracture surfaces in brittle geomaterials." Review of Scientific Instruments 80(12) - Tatone, B. and G. Grasselli (2012). "An Investigation of Discontinuity Roughness Scale Dependency Using High-Resolution Surface Measurements." Rock Mechanics and Rock Engineering: 1-25.

An Interactive Virtual 3D Tool for Scientific Exploration of Planetary Surfaces

NASA Astrophysics Data System (ADS)

Traxler, Christoph; Hesina, Gerd; Gupta, Sanjeev; Paar, Gerhard

2014-05-01

In this paper we present an interactive 3D visualization tool for scientific analysis and planning of planetary missions. At the moment scientists have to look at individual camera images separately. There is no tool to combine them in three dimensions and look at them seamlessly as a geologist would do (by walking backwards and forwards resulting in different scales). For this reason a virtual 3D reconstruction of the terrain that can be interactively explored is necessary. Such a reconstruction has to consider multiple scales ranging from orbital image data to close-up surface image data from rover cameras. The 3D viewer allows seamless zooming between these various scales, giving scientists the possibility to relate small surface features (e.g. rock outcrops) to larger geological contexts. For a reliable geologic assessment a realistic surface rendering is important. Therefore the material properties of the rock surfaces will be considered for real-time rendering. This is achieved by an appropriate Bidirectional Reflectance Distribution Function (BRDF) estimated from the image data. The BRDF is implemented to run on the Graphical Processing Unit (GPU) to enable realistic real-time rendering, which allows a naturalistic perception for scientific analysis. Another important aspect for realism is the consideration of natural lighting conditions, which means skylight to illuminate the reconstructed scene. In our case we provide skylights from Mars and Earth, which allows switching between these two modes of illumination. This gives geologists the opportunity to perceive rock outcrops from Mars as they would appear on Earth facilitating scientific assessment. Besides viewing the virtual reconstruction on multiple scales, scientists can also perform various measurements, i.e. geo-coordinates of a selected point or distance between two surface points. Rover or other models can be placed into the scene and snapped onto certain location of the terrain. These are important features to support the planning of rover paths. In addition annotations can be placed directly into the 3D scene, which also serve as landmarks to aid navigation. The presented visualization and planning tool is a valuable asset for scientific analysis of planetary mission data. It complements traditional methods by giving access to an interactive virtual 3D reconstruction, which is realistically rendered. Representative examples and further information about the interactive 3D visualization tool can be found on the FP7-SPACE Project PRoViDE web page http://www.provide-space.eu/interactive-virtual-3d-tool/. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 312377 'PRoViDE'.

Spectrometer Observations Near Mawrth Vallis

NASA Technical Reports Server (NTRS)

2006-01-01

This targeted image from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) shows a region of heavily altered rock in Mars' ancient cratered highlands. The featured region is just south of Mawrth Vallis, a channel cut by floodwaters deep into the highlands.

CRISM acquired the image at 1216 UTC (8:16 a.m. EDT) on Oct. 2, 2006, near 25.4 degrees north latitude, 340.7 degrees east longitude. It covers an area about 13 kilometers (8 miles) long and, at the narrowest point, about 9 kilometers (5.6 miles) wide. At the center of the image, the spatial resolution is as good as 35 meters (115 feet) per pixel. The image was taken in 544 colors covering 0.36-3.92 micrometers.

This image includes four renderings of the data, all map-projected. At top left is an approximately true-color representation. At top right is false color showing brightness of the surface at selected infrared wavelengths. In the two bottom views, brightness of the surface at different infrared wavelengths has been compared to laboratory measurements of minerals, and regions that match different minerals have been colored. The bottom left image shows areas high in iron-rich clay, and the bottom right image shows areas high in aluminum-rich clay.

Clay minerals are important to understanding the history of water on Mars because their formation requires that rocks were exposed to liquid water for a long time. Environments where they form include soils, cold springs, and hot springs. There are many clay minerals, and which ones form depends on the composition of the rock, and the temperature, acidity, and salt content of the water. CRISM's sister instrument on the Mars Express spacecraft, OMEGA, has spectrally mapped Mars at lower spatial resolution and found several regions rich in clay minerals. The Mawrth Vallis region, in particular, was found to contain iron-rich clay. CRISM is observing these regions at several tens of times higher spatial resolution, to correlate the minerals with different rock formations and to search for new minerals not resolved by OMEGA.

CRISM has found that the iron-rich clays (lower left image) correspond with a layer of rock that is dark red in the true color view (upper left) and bright gray in the infrared (upper right). In addition, it has found previously undetected exposures of aluminum-rich clay, in a rock unit that is buff-colored in the true color view, and bluish in the infrared. Both types of rocks formed early in Mars' history, about 3.8 billion years ago. The difference in clay mineralogy reveals differences in the environment either over time or over a distance of kilometers. CRISM will be taking many more images of the Mawrth Vallis region to piece together the geologic history of this fascinating area that was once a wet oasis on Mars.

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials -- leading to new understanding of the climate.

NASA's Jet Propulsion Laboratory, a division of the Califonia Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor and built the spacecraft.

Rapid formation of rock armour for soil - rock fragment mixture during simulated rainfall

NASA Astrophysics Data System (ADS)

Poultney, E.; McGrath, G. S.; Hinz, C.

2009-04-01

Preventing erosion is an important issue in disturbed semi-arid and arid landscapes. This is in particular of highest importance for mining companies while undertaking land rehabilitation. An onsite investigation of the impact of surface rock fragments on erosion was conducted at Telfer goldmine in the Great Sandy Desert, Western Australia. The study site is a waste rock dump designed to mimic the concave slope of a natural mesa to both discourage erosion and blend in with its natural surroundings. Four treatments were used to construct the slope: two are topsoil mixed with rock fragments, and two are unmixed topsoil. A field study investigating erosion rills, particle size distribution, rock fragment coverage surface roughness and vegetation was carried out to determine changes down and across slope. The treatments constructed by mixing topsoil and rock fragments are more stable and show rock fragment distributions that more closely resemble patterns found on natural mesas surrounding Telfer. A controlled study using trays of topsoil mixed with rock fragment volumes of 50%, 60%, 70% and 80% were used to investigate how varying mixtures of rock fragments and topsoil erode using rainfall intensities between 20 and 100 mm h-1. Two runs of 25 minutes each were used to assess the temporal evolution of rock armouring. Surface coverage results converged for the 50%, 60% and 70% mixtures after the first run to coverage of about 90%, suggesting that fine sediment proportion does not affect rate and degree of rock armouring.

Volunteer revegetation of waste rock surfaces at the Bingham Canyon Mine, Utah.

PubMed

Borden, Richard K; Black, Rick

2005-01-01

Voluntary recolonization of sulfide-bearing waste rock dumps by native vegetation is inhibited by the harsh chemical and physical conditions. The success of volunteer vegetation on the waste rock surfaces at the Bingham Canyon (Utah) porphyry copper deposit is most strongly dependent on the soil pH and salinity, and to a lesser extent on physical characteristics such as compaction and distance from seed source. Vegetation cover and richness both decline below a paste pH of about 6 and above a paste conductivity of about 0.7 dS/m (for a 1:1 soil to water mixture). No significant vegetation establishment occurs below a soil pH of about 4.5. Young sulfide-bearing waste rock surfaces at Bingham Canyon have high salinity, but as reactive pyrite is depleted and salts are flushed from the soil, the salinity eventually declines, allowing volunteer native vegetation to become established on surfaces with a circumneutral pH. Under natural conditions, the pH of older acidic weathered surfaces will recover very slowly, but it can be rapidly raised by adding relatively small amounts of limestone because there are few intact reactive sulfides. For uncompacted waste rock surfaces with favorable chemical conditions, less than 90% gravel content, and that are located near a native seed source, the arithmetic mean volunteer vegetation cover was 56 +/- 24% and the mean species richness was 17 +/- 5. These data indicate that with adequate surface preparation and limestone addition, direct planting of older, acidic, but low salinity waste rock surfaces can greatly accelerate natural revegetation.

A Model for Generation of Martian Surface Dust, Soil and Rock Coatings: Physical vs. Chemical Interactions, and Palagonitic Plus Hydrothermal Alteration

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Murchie, S.; Pieters, C.; Zent, A.

1999-01-01

This model is one of many possible scenarios to explain the generation of the current surface material on Mars using chemical, magnetic and spectroscopic data from Mars and geologic analogs from terrestrial sites. One basic premise is that there are physical and chemical interactions of the atmospheric dust particles and that these two processes create distinctly different results. Physical processes distribute dust particles on rocks, forming physical rock coatings, and on the surface between rocks forming soil units; these are reversible processes. Chemical reactions of the dust/soil particles create alteration rinds on rock surfaces or duricrust surface units, both of which are relatively permanent materials. According to this model the mineral components of the dust/soil particles are derived from a combination of "typical" palagonitic weathering of volcanic ash and hydrothermally altered components, primarily from steam vents or fumeroles. Both of these altered materials are composed of tiny particles, about 1 micron or smaller, that are aggregates of silicates and iron oxide/oxyhydroxide/sulfate phases. Additional information is contained in the original extended abstract.

An Overview of Downhole Imaging Tools

NASA Astrophysics Data System (ADS)

Luthi, S. M.

In this presentation we give an overview of downhole imaging tools that can be used to image the borehole wall and its vicinity with a variety of physical methods. Among these are ultrasonic scans with a rotating transducer that performs a pulse-echo mea- surement in rapid succession. This gives a transit time and a reflected amplitude image of the borehole wall. Electrical imaging is done with a whole family of measurements that operate mostly in the low AC range. All of them feature a number of electrodes that is inversely proportional to the desired resolution and depth of investigation. They image layering, fracturing and other heterogeneities in the rocks traversed by the bore- hole. Some of these images can be recorded and transmitted to the surface in real-time while the well is being drilled. Imaging using nuclear methods is also possible, for ex- ample for the natural radioactivity, density, or neutron porosity of the rock. However, these devices have generally low spatial resolutions. Finally, optical imaging is pos- sible in translucent and slightly opaque muds with a downhole video camera. Recent developments have resulted in a device that can withstand high pressures and temper- atures and that transmits live video images to the surface in real-time. This method has the highest resolution but is of limited applicability in the oil industry where gener- ally opaque muds are used. These images can be successfully used to determined the structural and intrinsic properties of rock traversed by a borehole.

Observation of the geology and geomorphology of the 1999 Marsokhod test site

USGS Publications Warehouse

De Hon, R. A.; Barlow, N.G.; Reagan, M.K.; Bettis, E. Arthur; Foster, C.T.; Gulick, V.C.; Crumpler, L.S.; Aubele, J.C.; Chapman, M.G.; Tanaka, K.L.

2001-01-01

The Marsokhod rover returned data from six stations that were used to decipher the geomorphology and geology of a region not previously visited by members of the geomorphology field team. Satellite images and simulated descent images provided information about the regional setting. The landing zone was on an alluvial apron flanking a mountain block to the west and a playa surface to the east. Rover color images, infrared spectra analysis of the mountains, and the apron surface provided insight into the rock composition of the nearby mountains. From the return data the geomorphology team interpreted the region to consist of compressionally deformed, ancient marine sediments and igneous rocks exposed by more recent extensional tectonics. Unconsolidated alluvial materials blanket the lower flanks of the mountains. An ancient shoreline cut into alluvial material marks a high stand of water during a past, wetter climate period. Playa sediments floor a present-day, seasonally, dry lake. Observations made by the rover using panoramic and close-up (hand specimens-scale) image data and color scene data confirmed the presence of boulders, cobbles, and fines of various provinces. Rover traverses to sites identified as geologically distinct, such as fan, channel, shoreline, and playa, provided useful clues to the geologic interpretations. Analysis of local rocks was given context only through comparison with distant geologic features. These results demonstrated the importance of a multifaceted approach to site interpretation through comparison of interpretations derived by differing geologic techniques. Copyright 2001 by the American Geophysical Union.

The Rocks of Gusev Crater as Viewed by Mini-TES

NASA Technical Reports Server (NTRS)

Ruff, S. W.; Christensen, P. R.; Blaney, D. L.

2005-01-01

We are developing the means to separate atmospheric spectral features from rock spectra. Measurements made in the late afternoon when the temperature difference between the rocks and sky is the greatest provide spectra that are least impacted by downwelling radiance. Additionally, the long wavelength range of Mini-TES spectra contain spectral features that are least effected by contributions from the atmosphere due to its relative transparency in this range. Mini-TES spectra have thus been used to reveal the geological diversity in Gusev crater and will continue to be a rich source of mineralogical information as Spirit continues its traverse.

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

Many of the moving rocks are about the size of a loaf of bread and weigh about 25 pounds. Interns Kristopher Schwebler and Valerie Fox make notes about this one. Photo credit: NASA/GSFC/Leva McIntire/LPSA intern To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

The summer interns with the 2010 Lunar and Planetary Science Academy (LPSA) at NASA's Goddard Space Flight Center came to study the Racetrack Playa rocks. Photo credit: NASA/GSFC/Mindy Krzykowski/LPSA intern To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Overview of Mars Science Laboratory (MSL) Environmental Program

NASA Technical Reports Server (NTRS)

Forgave, John C.; Man, Kin F.; Hoffman, Alan R.

2006-01-01

This viewgraph presentation is an overview of the Mars Science Laboratory (MSL) program. The engineering objectives of the program are to create a Mobile Science Laboratory capable of one Mars Year surface operational lifetime (670 Martian sols = 687 Earth days). It will be able to land and operation over wide range of latitudes, altitudes and seasons It must have controlled propulsive landing and demonstrate improved landing precision via guided entry The general science objectives are to perform science that will focus on Mars habitability, perform next generation analytical laboratory science investigations, perform remote sensing/contact investigations and carry a suite of environmental monitoring instruments. Specific scientific objectives of the MSL are: (1) Characterization of geological features, contributing to deciphering geological history and the processes that have modified rocks and regolith, including the role of water. (2) Determination of the mineralogy and chemical composition (including an inventory of elements such as C, H, N, O, P, S, etc. known to be building blocks for life) of surface and near-surface materials. (3) Determination of energy sources that could be used to sustain biological processes. (4) Characterization of organic compounds and potential biomarkers in representative regolith, rocks, and ices. (5) Determination the stable isotopic and noble gas composition of the present-day bulk atmosphere. (6) Identification potential bio-signatures (chemical, textural, isotopic) in rocks and regolith. (7) Characterization of the broad spectrum of surface radiation, including galactic cosmic radiation, solar proton events, and secondary neutrons. (8) Characterization of the local environment, including basic meteorology, the state and cycling of water and C02, and the near-surface distribution of hydrogen. Several views of the planned MSL and the rover are shown. The MSL environmental program is to: (1) Ensure the flight hardware design is capable of surviving all the environments throughout its mission life time, including ground, transportation, launch, cruise, entry decent and landing (EDL) and surface operation environments. (2) Verify environmental testing and analysis have adequately validated the flight hardware's ability to withstand all natural, self-induced, and mission-activity-induced environments. The planned tests to ascertain the capability of the MSL to perform as desired are reviewed.

Bright Summer Afternoon on the Mars Utopian Planitia

NASA Technical Reports Server (NTRS)

1976-01-01

A UTOPIAN BRIGHT SUMMER AFTERNOON ON MARS--Looking south from Viking 2 on September 6, the orange-red surface of the nearly level plain upon which the spacecraft sits is seen strewn with rocks as large as three feet across. Many of these rocks are porous and sponge-like, similar to some of Earth's volcanic rocks. Other rocks are coarse-grained such as the large rock at lower left. Between the rocks, the surface is blanketed with fine-grained material that, in places, is piled into small drifts and banked against some of the larger blocks. The cylindrical mast with the orange cable is the low-gain antenna used to receive commands from Earth.

Chemistry of Rocks and Soils in Gusev Crater from the Alpha Particle X-ray Spectrometer

NASA Technical Reports Server (NTRS)

Gellert, R.; Rieder, R.; Anderson, R. C.; Brueckner, J.; Clark, B. C.; Dreibus, G.; Economou, T.; Klingelhoefer, G.; Lugmair, G. W.; Ming, D. W.

2005-01-01

The alpha particle x-ray spectrometer on the Spirit rover determined major and minor elements of soils and rocks in Gusev crater in order to unravel the crustal evolution of planet Mars. The composition of soils is similar to those at previous landing sites, as a result of global mixing and distribution by dust storms. Rocks (fresh surfaces exposed by the rock abrasion tool) resemble volcanic rocks of primitive basaltic composition with low intrinsic potassium contents. High abundance of bromine (up to 170 parts per million) in rocks may indicate the alteration of surfaces formed during a past period of aqueous activity in Gusev crater.

ARC-1979-AC79-7014

NASA Image and Video Library

1979-03-04

2:30 pm Photographer : JPL Range : 2.6 million km. ( 1.6 million miles ) Ganymede is Jupiter's largest satellite ( or moon ) With a radius of about 2600 km., about 1.5 times that of our moon, Ganymede has a bulk density of about 2.0 g/cc, almost half that of our moon, and is probably composed of rock and ice. The large dark regions, in the northeast quadrant, and the white spots, resemble features found on the moon, mare and impact respectively. The long white filaments resemble rays associated with impacts on the lunar surface. The various colors, other than the several blue, green, & orange dots, which are markings on the camera used for pointing determinations and are not physical markings, probably represent differing surface materials.

The Surface Chemical Composition of Lunar Samples and Its Significance for Optical Properties

NASA Technical Reports Server (NTRS)

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

1976-01-01

The surface iron, titanium, calcium, and silicon concentration in numerous lunar soil and rock samples was determined by Auger electron spectroscopy. All soil samples show a large increase in the iron to oxygen ratio compared with samples of pulverized rock or with results of the bulk chemical analysis. A solar wind simulation experiment using 2 keV energy alpha -particles showed that an ion dose corresponding to approximately 30,000 years of solar wind increased the iron concentration on the surface of the pulverized Apollo 14 rock sample 14310 to the concentration measured in the Apollo 14 soil sample 14163, and the albedo of the pulverized rock decreased from 0.36 to 0.07. The low albedo of the lunar soil is related to the iron + titanium concentration on its surface. A solar wind sputter reduction mechanism is discussed as a possible cause for both the surface chemical and optical properties of the soil.

Opportunity Takes a Last Look at Rock Exposure Before Heading to Victoria Crater False Color

NASA Image and Video Library

2006-08-24

This false-color image shows a circular indentation in a flat-topped rock surface. Around the edge of the hole is a fine layer of reddish dust. The rock is light tan and has a moderately cracked the surface. Around it is a layer of bluish sand and pebbles

First Photograph Taken On Mars Surface

NASA Image and Video Library

1996-12-12

This is the first photograph ever taken on the surface of the planet Mars. It was obtained by Viking 1 just minutes after the spacecraft landed successfully early today [July 20, 1976]. The center of the image is about 1.4 meters (five feet) from Viking Lander camera #2. We see both rocks and finely granulated material--sand or dust. Many of the small foreground rocks are flat with angular facets. Several larger rocks exhibit irregular surfaces with pits and the large rock at top left shows intersecting linear cracks. Extending from that rock toward the camera is a vertical linear dark band which may be due to a one-minute partial obscuration of the landscape due to clouds or dust intervening between the sun and the surface. Associated with several of the rocks are apparent signs of wind transport of granular material. The large rock in the center is about 10 centimeters (4 inches) across and shows three rough facets. To its lower right is a rock near a smooth portion of the Martian surface probably composed of very fine-grained material. It is possible that the rock was moved during Viking 1 descent maneuvers, revealing the finer-grained basement substratum; or that the fine-grained material has accumulated adjacent to the rock. There are a number of other furrows and depressions and places with fine-grained material elsewhere in the picture. At right is a portion of footpad #2. Small quantities of fine grained sand and dust are seen at the center of the footpad near the strut and were deposited at landing. The shadow to the left of the footpad clearly exhibits detail, due to scattering of light either from the Martian atmosphere or from the spacecraft, observable because the Martian sky scatters light into shadowed areas. http://photojournal.jpl.nasa.gov/catalog/PIA00381

Subsidence and collapse sinkholes in soluble rock: a numerical perspective

NASA Astrophysics Data System (ADS)

Kaufmann, Georg; Romanov, Douchko; Hiller, Thomas

2016-04-01

Soluble rocks such as limestone, gypsum, anhydrite, and salt are prone to subsidence and the sudden creation of collapse sinkholes. The reason for this behaviour stems from the solubility of the rock: Water percolating through fissures and bedding partings can remove material from the rock walls and thus increase the permeability of the host rock by orders of magnitudes. This process occurs on time scales of 1,000-100,000 years, resulting in enlarged fractures, voids and cavities, which then carry flow efficiently through the rock. The enlargement of sub-surface voids to the meter-size within such short times creates mechanical conditions prone to collapse. The collapse initiates at depth, but then propagates to the surface. By means of numerical modelling, we discuss the long-term evolution of secondary porosity in gypsum rocks, resulting in zones of sub-surface voids, which then become mechanically unstable and collapse. We study two real-world case scenarios, in which we can relate field observations to our numerical model: (i) A dam-site scenario, where flow around the dam caused widespread dissolution of gypsum and subsequent subsidence of the dam and a nearby highway. (ii) A natural collapse sinkhole forming as a result of freshwater inflow into a shallow anhydrite formation with rapid evolution of voids in the sub-surface.

Selection of basic data for numerical modeling of rock mass stress state at Mirny Mining and Processing Works, Alrosa Group of Companies

NASA Astrophysics Data System (ADS)

Bokiy, IB; Zoteev, OV; Pul, VV; Pul, EK

2018-03-01

The influence of structural features on the strength and elasticity modulus is studied in rock mass in the area of Mirny Mining and Processing Works. The authors make recommendations on the values of physical properties of rocks.

Extreme Rock Distributions on Mars and Implications for Landing Safety

NASA Technical Reports Server (NTRS)

Golombek, M. P.

2001-01-01

Prior to the landing of Mars Pathfinder, the size-frequency distribution of rocks from the two Viking landing sites and Earth analog surfaces was used to derive a size-frequency model, for nomimal rock distributions on Mars. This work, coupled with extensive testing of the Pathfinder airbag landing system, allowed an estimate of what total rock abundances derived from thermal differencing techniques could be considered safe for landing. Predictions based on this model proved largely correct at predicting the size-frequency distribution of rocks at the Mars Pathfinder site and the fraction of potentially hazardous rocks. In this abstract, extreme rock distributions observed in Mars Orbiter Camera (MOC) images are compared with those observed at the three landing sites and model distributions as an additional constraint on potentially hazardous surfaces on Mars.

Preliminary results from an investigation of AIS-1 data over an area of epithermal alteration: Plateau, Northern Queensland, Australia

NASA Technical Reports Server (NTRS)

Mackin, Steve; Munday, Tim; Hook, Simon

1987-01-01

Airborne Imaging Spectrometer-1 (AIS-1) data were flown over undifferentiated sequences of acid to intermediate volcanics and intrusives; meta-sediments; and a series of partially lateritized sedimentary rocks. The area exhibits a considerable spectral variability, after the suppression of striping effects. Log residual, and Internal Average Relative Reflectance (IARR) analytical techniques were used to enhance mineralogically related spectral features. Both methods produce similar results, but did not visually highlight mineral absorption features due to processing artifacts in areas of significant vegetation cover. The enhancement of mineral related absorption features was achieved using a hybrid processing approach based on the relative reflectance differences between vegetated and non-vegetated surfaces at 1.2 and 2.1 micron. The result is an image with little overall contrast, but which enhances the more subtle spectral features believed to be associated with clays and epidote. The AIS data was subject to interactive analysis using SPAM. Clear separation of clay and epidote related absorption features was apparent, and the identification of kaolinite was possible despite detrimental spectral effects.

First attempt to study rock glaciers in New Zealand using the Schmidt-hammer - framework and preliminary results

NASA Astrophysics Data System (ADS)

Winkler, Stefan; Lambiel, Christophe; Sattler, Katrin; Büche, Thomas; Springer, Johanna

2016-04-01

Although not uncommon within the dryer eastern parts of the Southern Alps, New Zealand, comparatively few previous studies have previously focused on rock glacier dynamics and spatial distribution. Neither investigations of their chronological constraints nor any studies on actual rock glacier velocities have yet been carried out. Rock glaciers and periglacial processes still largely constitute a largely unexplored albeit potentially valuable field of research in the Southern Alps. The high-altitude valley head of Irishman Stream in the Ben Ohau Range between Lakes Ohau and Pukaki, roughly 30 km southeast of the Main Divide, contains a few morphologically intact rock glaciers and some appear to be active features (Sattler et al. 2016). Previous work focusing on the Late-glacial and early Holocene moraines in the valley head below the rock glaciers (Kaplan et al. 2010) provided 10Be-ages that could be utilised as fixed points for SHD (Schmidt-hammer exposure-age dating). Apart from detailed Schmidt-hammer sampling on the Late-glacial and early Holocene moraines, two altitudinal transects from the toe to their apex have been measured in detail on selected rock glaciers. On each of the multiple ridges of the rock glacier surface three sites of 50 boulders have been sampled with one impact each by the hammer (an N-type electronic SilverSchmidt by Proceq). Apart from getting some age constraints of these periglacial features in comparison to the well-dated moraines, the Schmidt-hammer measurements also had the aim to provide some insight into their genetic development resulting in a quite complex morphology of the rock glaciers and partial interaction with some of the moraines. Both altitudinal transects reveal a clear and continuous trend of increasing means (i.e. less weathered/younger exposure ages) towards their apex. The values for the individual ridges show, however, a transitional character with adjacent ridges albeit the abovementioned trend not statistically significant different in age, a phenomena known from similar studies on rock glaciers elsewhere. Already during sampling it became obvious that with increasing altitude and decreasing distance to the valley headwall the percentage of freshly appearing boulders vs. weathered boulders with a distinct micro-relief is getting higher. The means of the lowermost ridges of the rock glaciers show, however, no significant difference to the early Holocene moraines dated to c. 11.5 10Be ka ago. This may indicate that rock glacier formation initiated shortly after Termination 1 during the early Holocene and partly overrode some parts of the early Holocene moraines. During the field work, a network of 46 differential GPS points has been established to start future monitoring of any potential rock glacier movement. It will allow exploring the climatological control on rock glacier behaviour in in the Southern Alps, as well as comparisons with current velocities measured in the European Alps. References: Kaplan, M.R., Schaefer, J., Denton, G.H., Barrell, D.J.A., Chinn, T.J.H., Putnam, A.E., Anderson, B.G., Finkel, R.C., Schwartz, R. & Doughty, A.M. (2010): Glacier retreat in New Zealand during the Younger DryasStadial. Nature 467, 194-197. Sattler, K., Anderson, B., Mackintosh, A., Norton, K., de Róiste, M. (2016): Estimating permafrost distribution in the maritime SouthernAlps, New Zealand, based on climatic conditions at rock glacier sites. Frontiers in Earth Science - Section Cryospheric Sciences. doi: 10.3389/feart.2016.00004.

THE NEAR SURFACE GEOLOGY AT ENIWETOK AND BIKINI ATOLLS.

DTIC Science & Technology

ROCK, *NUCLEAR EXPLOSIONS, BIKINI ATOLL, CRATERING, SURFACE PROPERTIES, PARTICLE SIZE, GEOPHYSICAL PROSPECTING, LIMESTONE, GEOLOGICAL SURVEYS, SAND, GRAVEL, CORAL REEFS, DRILLING, ROCK, MARSHALL ISLANDS , SANDSTONE, FRICTION, COMPRESSIVE PROPERTIES, SOILS.

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.

The effect of surface and season on playground injury rates

PubMed Central

Branson, Lara Joan; Latter, John; Currie, Gillian R; Nettel-Aguirre, Alberto; Embree, Tania; Hagel, Brent Edward

2012-01-01

OBJECTIVE: To examine the effect of season on playground surface injury rates. METHODS: Injuries were identified through student incident report forms used in school districts in Calgary (Alberta) and the surrounding area. Playground surface exposure data were estimated based on school enrollment. RESULTS: A total of 539 injuries were reported during the 2007/2008 school year. Abrasions, bruises and inflammation were the most frequently reported injuries. The head, neck or face were most commonly injured. Injury rates per 1000 student days ranged between 0.018 (rubber crumb in spring) and 0.08 (poured-in-place and natural rock in the fall). Rubber crumb surfacing, compared with natural rock, had a significantly lower rate of injury in the spring, but no other season-surface comparisons were statistically significant. CONCLUSIONS: Rates of injury were similar for natural rock, poured-in-place, and crushed rock in the fall and winter. There was some evidence of a lower rate of injury on rubber crumb surfaces in the spring. PMID:24179416

Dissolution of bedded rock salt: A seismic profile across the active eastern margin of the Hutchinson Salt Member, central Kansas

USGS Publications Warehouse

Anderson, N.L.; Hopkins, J.; Martinez, A.; Knapp, R.W.; Macfarlane, P.A.; Watney, W.L.; Black, R.

1994-01-01

Since late Tertiary, bedded rock salt of the Permian Hutchinson Salt Member has been dissolved more-or-less continuously along its active eastern margin in central Kansas as a result of sustained contact with unconfined, undersaturated groundwater. The associated westward migration of the eastern margin has resulted in surface subsidence and the contemporaneous sedimentation of predominantly valley-filling Quarternary alluvium. In places, these alluvium deposits extend more than 25 km to the east of the present-day edge of the main body of contiguous rock salt. The margin could have receded this distance during the past several million years. From an environmental perspective, the continued leaching of the Hutchinson Salt is a major concern. This predominantly natural dissolution occurs in a broad zone across the central part of the State and adversely affects groundwater and surface-water quality as nonpoint source pollution. Significant surface subsidence occurs as well. Most of these subsidence features have formed gradually; others developed in a more catastrophic manner. The latter in particular pose real threats to roadways, railways, and buried oil and gas pipelines. In an effort to further clarify the process of natural salt dissolution in central Kansas and with the long-term goal of mitigating the adverse environmental affects of such leaching, the Kansas Geological Survey acquired a 4-km seismic profile across the eastern margin of the Hutchinson Salt in the Punkin Center area of central Kansas. The interpretation of these seismic data (and supporting surficial and borehole geologic control) is consistent with several hypotheses regarding the process and mechanisms of dissolution. More specifically these data support the theses that: 1. (1) Dissolution along the active eastern margin of the Hutchinson Salt Member was initiated during late Tertiary. Leaching has resulted in the steady westward migration of the eastern margin, surface subsidence, and the contemporaneous deposition of predominantly valley-filling Quarternary alluvium. 2. (2) Along the active eastern margin, the rock salt has been leached vertically from the top down, and horizontally along the uppermost remnant bedded soluble layer(s). As a result, the eastern margin thickens gradually (up to 90 m) and in a stepwise manner from east to west for distances on the order 5-15 km. 3. (3) In places, the Hutchinson Salt Member has been leached locally along NNE-trending paleoshear zones situated to the west of the present-day edge of the main body of contiguous rock salt. Leaching at these sites initiated when the main dissolution front impinged upon preexisting shear zones. ?? 1994.

Long term monitoring of rock surface temperature and rock cracking in temperate and desert climates

NASA Astrophysics Data System (ADS)

Eppes, M. C.; Warren, K.; Hinson, E.; Dash, L.

2012-12-01

The extent to which diurnal cycling of temperature results in the mechanical breakdown of rock cannot be clearly defined until direct connections between rock surface temperatures and rock cracking are identified under natural conditions. With this goal, we have developed a unique instrumentation system for monitoring spatial (N-, S-, E-, W-, up- and down-facing) and temporal (per minute) temperature variability in natural boulders while simultaneously monitoring cracking via acoustic emission sensors. To date, we have collected 11 and 12 months of data respectively for ~30 cm diameter granite boulders placed in North Carolina (near Charlotte) and New Mexico (Sevilleta National Wildlife Refuge). These data allow us 1) to compare and contrast spatial and temporal trends in surface temperatures of natural boulders at high temporal resolution over unprecedentedly long time scales in two contrasting environments and 2) to make direct correlations between boulder surface temperatures and periods of microcracking as recorded by acoustic emissions in both environments. Preliminary analysis of both data sets indicates that there is no obvious single high or low threshold in surface temperature or rate of surface temperature change (measurable at a per minute scale) beyond which cracking occurs for either locality. For example, for the New Mexico rock, overall rock surface temperatures ranged from -27 C to 54 C throughout the year, and rock surface temperatures during the times of peak cracking event clusters ranged from -14 C to 46 C. The majority of events occur during winter months in North Carolina and in summer in New Mexico. The majority of events occurred in the late afternoon/early evening for both localities, although the overall numbers of cracking events was significantly higher in the New Mexico locality. In both cases, the key temperature factor that appears to most often correlate with cracking is the rate of change of temperature difference across the rock surface. Large clusters of microcracking events commonly occur when the thermal gradient across the rock is rapidly changing, both positively or negatively. In most cases, this condition arises due to periods of rapid temperature change of the rock's upper surface associated with changing cloud cover, increased or decreased wind speed, or sudden rain events that follow sunny periods. As such, it appears that microcracking is often not solely associated with solar-related patterns of diurnal heating and cooling per-sea, but instead associated with weather conditions that lead to abrupt alterations of the diurnal pattern. Thus, the fact that clusters of events occur during specific times of day can be attributed to overall diurnal insolation patterns combined with rapid changes in weather that often occur during specific times of day as well. These data support the interpretation of documented preferential orientations of cracks in a variety of environments as having been formed due to stresses that arise by diurnal heating and cooling during specific times of day. As such, these data provide important inputs for numeric models by our collaborators, B. Hallet and P. Makenzie that seek to determine the exact thermo-mechanical mechanisms that link thermal cycling and rock fracture.

An ecological mechanism to create regular patterns of surface dissolution in a low-relief carbonate landscape

NASA Astrophysics Data System (ADS)

Cohen, M. J.; Martin, J. B.; Mclaughlin, D. L.; Osborne, T.; Murray, A.; Watts, A. C.; Watts, D.; Heffernan, J. B.

2012-12-01

Development of karst landscapes is controlled by focused delivery of water undersaturated with respect to the soluble rock minerals. As that water comes to equilibrium with the rock, secondary porosity is incrementally reinforced creating a positive feedback that acts to augment the drainage network and subsequent water delivery. In most self-organizing systems, spatial positive feedbacks create features (in landscapes: patches; in karst aquifers: conduits) whose size-frequency relationship follows a power function, indicating a higher probability of large features than would occur with a random or Gaussian genesis process. Power functions describe several aspects of secondary porosity in the Upper Floridan Aquifer in north Florida. In contrast, a different pattern arises in the karst landscape in southwest Florida (Big Cypress National Preserve; BICY), where low-relief and a shallow aquiclude govern regional hydrology. There, the landscape pattern is highly regular (Fig. 1), with circular cypress-dominated wetlands occupying depressions that are hydrologically isolated and distributed evenly in a matrix of pine uplands. Regular landscape patterning results from spatially coupled feedbacks, one positive operating locally that expands patches coupled to another negative that operates at distance, eventually inhibiting patch expansion. The positive feedback in BICY is thought to derive from the presence of surface depressions, which sustain prolonged inundation in this low-relief setting, and facilitate wetland development that greatly augments dissolution potential of infiltrating water in response to ecosystem metabolic processes. In short, wetlands "drill" into the carbonate leading to both vertical and lateral basin expansion. Wetland expansion occurs at the expense of surrounding upland area, which is the local catchment that subsidizes water availability. A distal inhibitory feedback on basin expansion thus occurs as the water necessary to sustain prolonged inundation becomes limiting. The implied strong reciprocal coupling between surface production of organic matter and patterns of induced subsurface carbonate dissolution are a novel example of co-evolving biogeomorphic processes in the earth system. Fig. 1 - Regular patterned landscape in Big Cypress National Preserve showing cypress dominated wetlands (round features) embedded in a mosaic of pine and grass uplands. Exposed carbonate rings are evident at the margins of many of the wetland basins.

[Hydrochemistry and Dissolved Inorganic Carbon Stable Isotope of Shibing Dolomite Karst Area in Guizhou Province].

PubMed

Xiao, Shi-zhen; Lan, Jia-cheng; Yuan, Dao-xian; Wang, Yun; Yang, Long; Ao, Xiang-hong

2015-06-01

Totally 49 water samples were collected in Shibing Dolomite Karst World Natural Heritage Site in Guizhou Province to analyze the characteristics and controlling factors of both the surface and underground waters, as well as the features and their origins of the dissolved inorganic carbon isotope. It was found that the pH of the study area was neutral to alkaline with low concentrations of total dissolved solids. The cations were dominated by Ca2+, Mg2 and anions by HCO3-, featured by HCO3-Ca x Mg type water. The ratios of Cl-, NO3- and SO4(2-) in the allogenic water from the shale area in the northern catchment were higher than those in autogenic water from the dolomite karst area, so did the concentration of Si. The SIc and SId of the allogenic waters in the shale area were negative. After the waters entered into and flew by the dolomite karst area, both the SIc and SId increased to over 0. It could be told by the water chemistry that the hydrochemistry was little impacted by the rainfall and human activities. The Gibbs plot revealed that the chemical composition of the waters was mainly controlled by rock weathering. The δ(13)C(DIC) of the surface waters ranged from -8.27% to -11.55% per hundred, averaging -9.45% per hundredo, while that of the underground waters ranged from -10.57% per hundred to -15.59% per hundred, averaging -12.04% per hundred, which was lighter than that of surface water. For the distribution features, it was found the δ(13)C(DIC), of the upper reaches of branches of Shangmuhe River was lighter than that of the lower reach, while that of the main river Shangmuhe River was relatively complex. Based on the mass balance of stable isotopes and the δ(13)C(DIC), the ratio of the origin of DIC of the ground water was calculated. It was found that 51.2% was from soil CO2, and 48.8% was from the rock itself.

Pore Effect on the Occurrence and Formation of Gas Hydrate in Permafrost of Qilian Mountain, Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Gao, H.; Lu, H.; Lu, Z.

2014-12-01

Gas hydrates were found in the permafrost of Qilian Mountain, Qinghai- Tibet Plateau, China in 2008. It has been found that gas hydrates occur in Jurassic sedimentary rocks, and the hydrated gases are mainly thermogenic. Different from the gas hydrates existing in loose sands in Mallik, Mackenzie Delta, Canada and North Slope, Alaska, USA, the gas hydrates in Qilian Mountain occurred in hard rocks. For understanding the occurrence and formation mechanism of gas hydrate in hard rcok, extensive experimental investigations have been conducted to study the pore features and hydrate formation in the rocks recovered from the hydrate layers in Qilian Mountain. The structures of sedimentary rock were observed by high-resolution X-ray CT, and pore size distribution of a rock specimen was measured with the mercury-injection method. Methane hydrate was synthesized in water-saturated rocks, and the saturations of hydrate in sedimentary rocks of various types were estimated from the amount of gas released from certain volume of rock. X-ray CT observation revealed that fractures were developed in the rocks associated with faults, while those away from faults were generally with massive structure. The mercury-injection analysis of pore features found that the porosities of the hydrate-existing rocks were generally less than 3%, and the pore sizes were generally smaller than 100 nm. The synthesizing experiments found that the saturation of methane hydrate were generally lower than 6% of pore space in rocks, but up to 16% when fractures developed. The low hydrate saturation in Qilian sedimentary rocks has been found mainly due to the small pore size of rock. The low hydrate saturation in the rocks might be the reason for the failure of regional seismic and logging detections of gas hydrates in Qilian Mountain.

Water-soluble low-molecular-weight organic acids in automorphic loamy soils of the tundra and taiga zones

NASA Astrophysics Data System (ADS)

Shamrikova, E. V.; Gruzdev, I. V.; Punegov, V. V.; Khabibullina, F. M.; Kubik, O. S.

2013-06-01

The formation features of water-soluble low-molecular-weight organic acids (LMWOAs) in a zonal series of automorphic soils on loose silicate rocks from the middle taiga to the southern tundra (typical podzolic, gley-podzolic, and surface-gley tundra soils) were first revealed by gas chromatography mass spectrometry and gas-liquid chromatography. The content of LMWOAs varies within the range of 1-14 mg/dm3, which corresponds to 1-5% of the total carbon of the water-soluble soil organic matter. It has been shown that a subzonal feature of gley-podzolic soils in the northern taiga is the high content of LMWOAs, including primarily the strongest aliphatic hydroxyl acids. Possible mechanisms of their formation and accumulation in soils have been considered.

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

The rocks are famous because they move, leaving tell-tale trails in the clay, like this one. This happens at several playa in California and Nevada. There's no record of anybody seeing one of the rocks move, and scientists aren't quite sure how it happens. But they know that it's not the work of animals, gravity, or earthquakes. Photo credit: NASA/GSFC/Cynthia Cheung To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Experiments and Spectral Studies of Martian Volcanic Rocks: Implications for the Origin of Pathfinder Rocks and Soils

NASA Technical Reports Server (NTRS)

Rutherford, Malcolm J.; Mustard, Jack; Weitz, Catherine

2002-01-01

The composition and spectral properties of the Mars Pathfinder rocks and soils together with the identification of basaltic and andesitic Mars terrains based on Thermal Emission Spectrometer (TES) data raised interesting questions regarding the nature and origin of Mars surface rocks. We have investigated the following questions: (1) are the Pathfinder rocks igneous and is it possible these rocks could have formed by known igneous processes, such as equilibrium or fractional crystallization, operating within SNC magmas known to exist on Mars? If it is possible, what P (depth) and PH2O conditions are required? (2) whether TES-based interpretations of plagioclase-rich basalt and andesitic terrains in the south and north regions of Mars respectively are unique. Are the surface compositions of these regions plagioclase-rich, possibly indicating the presence of old AI-rich crust of Mars, or are the spectra being affected by something like surface weathering processes that might determine the spectral pyroxene to plagioclase ratio?

Newly identified "Tunnunik" impact structure, Prince Albert Peninsula, northwestern Victoria Island, Arctic Canada

NASA Astrophysics Data System (ADS)

Dewing, Keith; Pratt, Brian R.; Hadlari, Thomas; Brent, Tom; BÉDard, Jean; Rainbird, Robert H.

2013-02-01

Regional geological mapping of the glaciated surface of northwestern Victoria Island in the western Canadian Arctic revealed an anomalous structure in otherwise flat-lying Neoproterozoic and lower Paleozoic carbonate rocks, located south of Richard Collinson Inlet. The feature is roughly circular in plan view, approximately 25 km in diameter, and characterized by quaquaversal dips of approximately 45°, decreasing laterally. The core of the feature also exhibits local vertical dips, low-angle reverse faults, and drag folds. Although brecciation was not observed, shatter cones are pervasive in all lithologies in the central area, including 723 Ma old dikes that penetrate Neoproterozoic limestones. Their abundance decreases distally, and none was observed in surrounding, horizontally bedded strata. This circular structure is interpreted as a deeply eroded meteorite impact crater of the complex type, and the dipping strata as the remnants of the central uplift. The variation in orientation and shape of shatter cones point to variably oriented stresses with the passage of the shock wave, possibly related to the presence of pore water in the target strata as well as rock type and lithological heterogeneities, especially bed thickness. Timing of impact is poorly constrained. The youngest rocks affected are Late Ordovician (approximately 450 Ma) and the impact structure is mantled by undisturbed postglacial sediments. Regional, hydrothermal dolomitization of the Ordovician limestones, possibly in the Late Devonian (approximately 360 Ma), took place before the impact, and widespread WSW-ENE-trending normal faults of probable Early Cretaceous age (approximately 130 Ma) apparently cross-cut the impact structure.

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

The trails have some curious features. Sometimes the clay gets pushed into a mound at the trail's end, as in this photo. Photo credit: NASA/GSFC/Cynthia Cheung To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Back-analysis of a large landslide in a heterogeneous rock mass

NASA Astrophysics Data System (ADS)

Berti, Matteo; Gamba, Alberto; Pizziolo, Marco

2014-05-01

On April 6, 2013 a large landslide occurred on the mountainside about 2 km above Castel dell'Alpi, a small community located on the Savena River valley (Province of Bologna, Northern Apennines, Italy). Three houses collapsed, two were seriously damaged, and the existing roads and infrastructures were destroyed. The landslide was a massive rotational slide about 900 m long, 600 m wide and covering an area of 0.3 km2. The estimated volume was about 3 million cubic meters. According to eyewitnesses, diffuse ground deformations appeared in the morning of April 6 along the road that runs at the toe of the slope, and became more and more prominent during the afternoon. The landslide suddenly accelerated during the night and moved downslope 50 to 100 m in a few hours. Fortunately, residents were alerted by the sound of cracking wood and left their houses in time, thus resulted in no fatalities or injuries. The landslide created a large, bowl-shaped scar with a steep scarp about 70 m height and 800 m long. The head of the landslide moved almost vertically downward and tilted backwards, while ground bulging and compressive structures occurred at the toe. These kinematic features indicate a strong rotational component of the slide, although the high degree of internal deformation suggests a non-perfectly circular slip surface. It is well known that rotational slides tend to occur in deep homogeneous material such as thick clay soils, weak rocks, or artificial fills. In this case, however, the failure involved a strongly heterogeneous flysch, apparently characterized by good mechanical resistance. The rock belongs to the Monghidoro Formation (Cretaceous sup.-Paleocene) and consists of thinly interbedded sandstone, marl, and shale. The rock mass outcropping on the main scarp is only slight to moderately weathered, with nearly-horizontal bedding planes. Therefore, failure conditions were probably reached within the "fresh" material and, despite its heterogeneity, the flysch behaved as an homogeneous medium at the slope scale. Such a behavior is typical of this rock. A number of old rotational slides can be found in the area, and they all show the morphological features (such as a steep arcuate scarp with exposed bedrock and sub-circular landslide deposit) that characterize rotational failures in homogeneous materials. The landslide of April 2013 thus provides the opportunity to investigate in depth the mechanical behavior of this complex formation. The analysis mainly focused on the evaluation of the mobilized shear strength at failure. The slope geometry before the failure was reconstructed by combining the pre-failure 5 m DEM, the post-failure 1 m DEM (LIDAR) and the kinematic interpretation of the geomorphological features. Mobilised shear strength parameters were compute by limit-equilibrium and finite-difference back-analyses, considering a wide variation of groundwater head levels, initial stress state, and slip surface depth. The results clearly indicate that the flysch is characterized by low mass strength and small effective cohesion (in the order of few tens of kPa). The mobilized cohesion is much lower than that predicted by the geomechanical classification of heterogeneous rock masses, and casts doubts on the reliability of such estimates for the prediction of large slope instability.

Mars rover rock abrasion tool performance enhanced by ultrasonic technology.

NASA Astrophysics Data System (ADS)

Macartney, A.; Li, X.; Harkness, P.

2016-12-01

The Mars exploration Athena science goal is to explore areas where water may have been present on the early surface of Mars, and investigate the palaeo-environmental conditions of these areas in relation to the existence of life. The Rock Abrasion Tool (RAT) designed by Honeybee Robotics has been one of four key Athena science payload instruments mounted on the mechanical arm of the Spirit, Opportunity and Curiosity Mars Exploration Rovers. Exposed rock surfaces weather and chemically alter over time. Although such weathered rock can present geological interest in itself, there is a limit to what can be learned. If the geological history of a landing site is to be constructed, then it is important to analyse the unweathered rock interior as clearly as possible. The rock abrasion tool's role is to substitute for a geologist's hammer, removing the weathered and chemically altered outer surface of rocks in order to view the pristine interior. The RAT uses a diamond resin standard common grinding technique, producing a 5mm depth grind with a relatively high surface roughness, achieved over a number of hours per grind and consumes approximately 11 watts of energy. This study assesses the benefits of using ultrasonic assisted grinding to improve surface smoothness. A prototype Micro-Optic UltraSonic Exfoliator (MOUSE) is tested on a range of rock types and demonstrates a number of advantages over the RAT. In addition to a smoother grind finish, these advantages include a lower rate of tool tip wear when using a tungsten carbide tip as opposed to diamond resin, less moving parts, a grind speed of minutes instead of hours, and a power consumption of only 1-5 Watts.

Water resources in the Big Lost River Basin, south-central Idaho

USGS Publications Warehouse

Crosthwaite, E.G.; Thomas, C.A.; Dyer, K.L.

1970-01-01

The Big Lost River basin occupies about 1,400 square miles in south-central Idaho and drains to the Snake River Plain. The economy in the area is based on irrigation agriculture and stockraising. The basin is underlain by a diverse-assemblage of rocks which range, in age from Precambrian to Holocene. The assemblage is divided into five groups on the basis of their hydrologic characteristics. Carbonate rocks, noncarbonate rocks, cemented alluvial deposits, unconsolidated alluvial deposits, and basalt. The principal aquifer is unconsolidated alluvial fill that is several thousand feet thick in the main valley. The carbonate rocks are the major bedrock aquifer. They absorb a significant amount of precipitation and, in places, are very permeable as evidenced by large springs discharging from or near exposures of carbonate rocks. Only the alluvium, carbonate rock and locally the basalt yield significant amounts of water. A total of about 67,000 acres is irrigated with water diverted from the Big Lost River. The annual flow of the river is highly variable and water-supply deficiencies are common. About 1 out of every 2 years is considered a drought year. In the period 1955-68, about 175 irrigation wells were drilled to provide a supplemental water supply to land irrigated from the canal system and to irrigate an additional 8,500 acres of new land. Average. annual precipitation ranged from 8 inches on the valley floor to about 50 inches at some higher elevations during the base period 1944-68. The estimated water yield of the Big Lost River basin averaged 650 cfs (cubic feet per second) for the base period. Of this amount, 150 cfs was transpired by crops, 75 cfs left the basin as streamflow, and 425 cfs left as ground-water flow. A map of precipitation and estimated values of evapotranspiration were used to construct a water-yield map. A distinctive feature of the Big Lost River basin, is the large interchange of water from surface streams into the ground and from the ground into the surface streams. Large quantities of water disappear in the Chilly, Darlington, and other sinks and reappear above Mackay Narrows, above Moore Canal heading, and in other reaches. A cumulative summary of water yield upstream from selected points in the basin is as follows : Above Howell Ranch: water yield: 345 cfs; surface water: 310 cfs; ground water: 35 cfs Above. Mackay Narrows water yield: 450 cfs; surface water: 325 cfs; ground water: 75 cfs; crop evapotranspiration: 50 cfs Above Arco: water yield: 650 cfs; surface water: 75 cfs; ground water: 425 cfs; crop evapotranspiration: 150 cfs Ground-water pumping affects streamflow in reaches , where the stream and water table are continuous, but the effects of pumping were not measured except locally. Pumping depletes the total water supply by the. amount of the pumped water that is evapotranspired by crops. The part of the pumped water that is not consumed percolates into the ground or runs off over the land surface to the stream. The estimated 425 cfs that leaves the basin as ground-water flow is more than adequate for present and foreseeable needs. However because much of the outflow occurs at considerable depth, the quantity that is salvageable is unknown. Both the surface and ground waters are of good quality and are suitable for most uses. Although these waters are low in total dissolved solids, they tend to be hard or very hard.

Geophysical anatomy of counter-slope scarps in sedimentary flysch rocks (Outer Western Carpathians)

NASA Astrophysics Data System (ADS)

Tábořík, P.; Lenart, J.; Blecha, V.; Vilhelm, J.; Turský, O.

2017-01-01

A multidisciplinary geophysical survey, consisting of electrical resistivity tomography (ERT), ground penetrating radar (GPR), shallow seismic refraction (SSR) and gravity survey (GS), was used to investigate the counter-slope scarps, one of the typical manifestations of the relaxed zones of rock massifs, and the possible initial stages of deep-seated landslides (DSLs). Two upper parts of the extensive DSLs within the Moravskoslezské Beskydy Mountains (Outer Western Carpathians - OWC) built by the sedimentary flysch rock were chosen as the testing sites. A combined geophysical survey on the flysch rocks was performed on both localities to enhance our present findings. The survey revealed that the ERT is able to reliably detect underground discontinuities, which are manifested at the ground surface by one of the typical landforms (tension cracks, trenches, pseudokarst sinkholes, double-crested ridges and counter-slope scarps). Previous studies suggested that bedrock discontinuities should be depicted by high-resistivity features within ERT surveying. According to SSR and GS, expected zones of weakened rock massif were not confirmed directly underneath the superficial landforms, but they were shifted. Based on the SSR and GS measurements, the depicted high-contrast transitions between high- and low-resistivity domains within the ERT profiles were newly identified as possible manifestation of bedrock discontinuities. The results of GPR measurements give only limited information on the sedimentary flysch rocks, due to shallow penetrating depth and locally strong signal attenuation. The combined results of multidisciplinary geophysical surveying confirmed an importance of employing more than one geophysical technique for integrated interpretations of measured data. Integrated interpretations of the measured geophysical data provided a new insight into massif disintegration and the geomorphic origin of the landforms related to the DSL.

New theoretical models and ratio imaging techniques associated with the NASA earth resources spectral information system

NASA Technical Reports Server (NTRS)

Vincent, R. K.

1974-01-01

Four independent investigations are reported; in general these are concerned with improving and utilizing the correlation between the physical properties of natural materials as evidenced in laboratory spectra and spectral data collected by multispectral scanners. In one investigation, two theoretical models were devised that permit the calculation of spectral emittance spectra for rock and mineral surfaces of various particle sizes. The simpler of the two models can be used to qualitatively predict the effect of texture on the spectral emittance of rocks and minerals; it is also potentially useful as an aid in predicting the identification of natural atmospheric aerosol constituents. The second investigation determined, via an infrared ratio imaging technique, the best pair of infrared filters for silicate rock-type discrimination. In a third investigation, laboratory spectra of natural materials were compressed into 11-digit ratio codes for use in feature selection, in searches for false alarm candidates, and eventually for use as training sets in completely automatic data processors. In the fourth investigation, general outlines of a ratio preprocessor and an automatic recognition map processor are developed for on-board data processing in the space shuttle era.

Spirit Studies Rock Outcrop at Home Plate

NASA Image and Video Library

2006-03-06

This image shows two flat-topped, layered rocks with angular edges almost side by side, except they are separated by a smaller rock and two thin channels of reddish-brown sand. The bare rock surfaces are a light blue-gray

Preliminary examination of lunar samples from apollo 14.

PubMed

1971-08-20

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

The historical and cultural heritage from Brazil: rocks and deterioration patterns

NASA Astrophysics Data System (ADS)

Costa, Antônio

2014-05-01

This summary provides information on the results of a research in progress, which focuses on the investigation of stone materials, as steatites, serpentinites, quartzites and schists, widely used in construction of buildings belonging to the cultural heritage of Brazil, especially in those that are in the state of Minas Gerais. These historic buildings, some of those with more than three hundred years of existence and constructed with the use of different rocks, function as open-air laboratories and because of that assists on the study of the deterioration of these materials. In its early stages, the research has focused on macroscopic characterization of the employed materials, following with the lifting of their respective areas of occurrence. Then samples for the survey of other features, such as its chemical and physical-mechanical properties were collected. The investigated physical-mechanical properties were as follows: thermal dilatation coefficient, compressive and flexural strength, abrasion resistance, water absorption coefficient by capillarity, real and apparent density, total and open porosity. Currently, the research focuses on issues such as: evidence of degradation and extent of deterioration in these monuments, as a result of the performance of different processes of alteration and decay. In this investigation it is understood that the first processes are associated with modifications of stone materials, which do not necessarily imply in worsening of the characteristics of these materials from the point of view of conservation and seconds are related to chemical and physical changes of intrinsic properties of rocks used in the construction of this heritage, which can lead to a loss of value, or some impediment of use, according to the indications of the illustrated glossary on patterns of deterioration of rocks proposed by ICOMOS. For this purpose macroscopic descriptions of monuments and its applied rocks, accompanied by detailed photographic record and sampling, this last whenever possible, were made. Through macroscopic descriptions was possible to identify the presence of numerous cracks, elevations and detachments of outer layers from some rocks, separation of layers, disaggregation of individual grains or aggregates of grains, loss of original surface due to mechanical action or not, resulting in the presence of smoothed shapes, loss of parts of sculptures, so as the presence of cavities or alveoli formed on the surface of the rock. Were also observed: the presence of crusts by accumulation of exogenous materials and rock itself, color changes, eflorescences, incrustations with surface morphology and color different from those of stone, patinas, graffiti as a result of vandalism and different degrees of biological colonization, involving the presence of mold, lichen, algae and plants. It is hoped that the data obtained may contribute to the indication of preservation methods most recommended for each case of observed deterioration. Considering that the majority of these materials remains exposed to external areas, these efforts will be sufficient only to delay the actions and minimize the effects of these processes of deterioration.

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

Geology of the Midnite uranium mine, Stevens County, Washington; a preliminary report

USGS Publications Warehouse

Nash, J. Thomas; Lehrman, Norman J.

1975-01-01

The Midnite mine is one of only two mines in the United States currently producing uranium from discordant deposits in crystalline host rocks. Ore bodies are in metamorphosed steeply dipping Precambrian pelitic and calcareous rocks of a roof pendant adjacent to a Cretaceous(?) porphyritic quartz monzonite pluton. Production during 14 years, of operation has been about 8 million pounds of U3O8 from oxidized and reduced ores averaging 0.23 percent U3O8. Uranium deposits are generally tabular in form and dimensions range up to 380 m long, 210 m wide, and 50 m thick. Deposits are bounded on at least one side by unmineralized intrusive ribs of granitic rock, and thickest mineralized zones invariably occur at depressions in the intrusive contact. Upper limits of some deposits are nearly horizontal, and upper elevations of adjacent mineralized zones separated by ribs of granite are similar. Near surface ore is predominantly autunite, but ore at depth consists of pitchblende and coffinite with abundant pyrite and marcasite. Uranium minerals occur as .disseminations along foliation, replacements, and stockwork fracture-fillings. No stratigraphic controls on ore deposition are recognized. Rather, mineralized zones cut across lithologic boundaries if permeability is adequate. Most ore is in muscovite schist and mica phyllite, but important deposits occur in calc-silicate hornfels. Amphibolite sills and mid-Tertiary dacite dikes locally, carry ore where intensely fractured. High content of iron and sulfur, contained chiefly in FeS2, appear to be an important feature of favorable host rocks. Geometry of deposits, structural, and geochemical features suggest that uranium minerals were deposited over a span of time from late Cretaceous to late Tertiary. Ore occurs in but is not offset by a shear zone that displaces mid-Tertiary rocks.. Economic zones of uranium are interpreted to have been secondarily enriched in late Tertiary time by downward and lateral migration of uranium into permeable zones where deposition was influenced by ground water controls and minerals that could reduce or neutralize uranium-bearing solutions.

Surface Properties and Characteristics of Mars Landing Sites from Remote Sensing Data and Ground Truth

NASA Astrophysics Data System (ADS)

Golombek, M. P.; Haldemann, A. F.; Simpson, R. A.; Furgason, R. L.; Putzig, N. E.; Huertas, A.; Arvidson, R. E.; Heet, T.; Bell, J. F.; Mellon, M. T.; McEwen, A. S.

2008-12-01

Surface characteristics at the six sites where spacecraft have successfully landed on Mars can be related favorably to their signatures in remotely sensed data from orbit and from the Earth. Comparisons of the rock abundance, types and coverage of soils (and their physical properties), thermal inertia, albedo, and topographic slope all agree with orbital remote sensing estimates and show that the materials at the landing sites can be used as ground truth for the materials that make up most of the equatorial and mid- to moderately high-latitude regions of Mars. The six landing sites sample two of the three dominant global thermal inertia and albedo units that cover ~80% of the surface of Mars. The Viking, Spirit, Mars Pathfinder, and Phoenix landing sites are representative of the moderate to high thermal inertia and intermediate to high albedo unit that is dominated by crusty, cloddy, blocky or frozen soils (duricrust that may be layered) with various abundances of rocks and bright dust. The Opportunity landing site is representative of the moderate to high thermal inertia and low albedo surface unit that is relatively dust free and composed of dark eolian sand and/or increased abundance of rocks. Rock abundance derived from orbital thermal differencing techniques in the equatorial regions agrees with that determined from rock counts at the surface and varies from ~3-20% at the landing sites. The size-frequency distributions of rocks >1.5 m diameter fully resolvable in HiRISE images of the landing sites follow exponential models developed from lander measurements of smaller rocks and are continuous with these rock distributions indicating both are part of the same population. Interpretation of radar data confirms the presence of load bearing, relatively dense surfaces controlled by the soil type at the landing sites, regional rock populations from diffuse scattering similar to those observed directly at the sites, and root-mean-squared slopes that compare favorably with 100 m scale topographic slopes extrapolated from altimetry profiles and meter scale slopes from high-resolution stereo images. The third global unit has very low thermal inertia and very high albedo, indicating it is dominated by deposits of bright red atmospheric dust that may be neither load bearing nor trafficable. The landers have thus sampled the majority of likely safe and trafficable surfaces that cover most of Mars and show that remote sensing data can be used to infer the surface characteristics, slopes, and surface materials present at other locations.

Geomorphic domains and linear features on Landsat images, Circle Quadrangle, Alaska

USGS Publications Warehouse

Simpson, S.L.

1984-01-01

A remote sensing study using Landsat images was undertaken as part of the Alaska Mineral Resource Assessment Program (AMRAP). Geomorphic domains A and B, identified on enhanced Landsat images, divide Circle quadrangle south of Tintina fault zone into two regional areas having major differences in surface characteristics. Domain A is a roughly rectangular, northeast-trending area of relatively low relief and simple, widely spaced drainages, except where igneous rocks are exposed. In contrast, domain B, which bounds two sides of domain A, is more intricately dissected showing abrupt changes in slope and relatively high relief. The northwestern part of geomorphic domain A includes a previously mapped tectonostratigraphic terrane. The southeastern boundary of domain A occurs entirely within the adjoining tectonostratigraphic terrane. The sharp geomorphic contrast along the southeastern boundary of domain A and the existence of known faults along this boundary suggest that the southeastern part of domain A may be a subdivision of the adjoining terrane. Detailed field studies would be necessary to determine the characteristics of the subdivision. Domain B appears to be divisible into large areas of different geomorphic terrains by east-northeast-trending curvilinear lines drawn on Landsat images. Segments of two of these lines correlate with parts of boundaries of mapped tectonostratigraphic terranes. On Landsat images prominent north-trending lineaments together with the curvilinear lines form a large-scale regional pattern that is transected by mapped north-northeast-trending high-angle faults. The lineaments indicate possible lithlogic variations and/or structural boundaries. A statistical strike-frequency analysis of the linear features data for Circle quadrangle shows that northeast-trending linear features predominate throughout, and that most northwest-trending linear features are found south of Tintina fault zone. A major trend interval of N.64-72E. in the linear feature data, corresponds to the strike of foliations in metamorphic rocks and magnetic anomalies reflecting compositional variations suggesting that most linear features in the southern part of the quadrangle probably are related to lithologic variations brought about by folding and foliation of metamorphic rocks. A second important trend interval, N.14-35E., may be related to thrusting south of the Tintina fault zone, as high concentrations of linear features within this interval are found in areas of mapped thrusts. Low concentrations of linear features are found in areas of most igneous intrusives. High concentrations of linear features do not correspond to areas of mineralization in any consistent or significant way that would allow concentration patterns to be easily used as an aid in locating areas of mineralization. The results of this remote sensing study indicate that there are several possibly important areas where further detailed studies are warranted.

Potential weathering by freeze-thaw action in alpine rocks in the European Alps during a nine year monitoring period

NASA Astrophysics Data System (ADS)

Kellerer-Pirklbauer, Andreas

2017-11-01

A quantification of rock weathering by freeze-thaw processes in alpine rocks requires at least rock temperature data in high temporal resolution, in high quality, and over a sufficient period of time. In this study up to nine years of rock temperature data (2006-2015) from eleven rock monitoring sites in two of the highest mountain ranges of Austria were analyzed. Data were recorded at a half-hourly or hourly logging interval and at rock depths of 3, 10, and 30-40 cm. These data have been used to quantify mean conditions, ranges, and relationships of the potential near-surface weathering by freeze-thaw action considering volumetric-expansion of ice and ice segregation. For the former, freeze-thaw cycles and effective freeze-thaw cycles for frost shattering have been considered. For the latter, the intensity and duration of freezing events as well as time within the 'frost cracking window' have been analyzed. Results show that the eleven sites are in rather extreme topoclimatic positions and hence represent some of the highest and coolest parts of Austria and therefore the Eastern Alps. Only four sites are presumably affected by permafrost. Most sites are influenced by a long-lasting seasonal snow cover. Freeze-thaw cycles and effective freeze-thaw cycles for frost shattering are mainly affecting the near-surface and are unimportant at few tens of centimeters below the rock surface. The lowest temperatures during freezing events and the shortest freezing events have been quantified at all eleven monitoring sites very close to the surface. The time within the frost cracking window decreases in most cases from the rock surface inwards apart from very cold years/sites with very low temperatures close to the surface. As shown by this study and predicted climate change scenarios, assumed warmer rock temperature conditions in the future at alpine rock walls in Austria will lead to less severe freezing events and to shorter time periods within the frost-cracking window. Statistical correlation analyses showed furthermore that the longer the duration of the seasonal snow cover, the fewer are freeze-thaw cycles, the fewer are effective freeze-thaw cycles, the longer is the mean and the maximum duration of freezing events, and the lower is the mean annual ground temperature. The interaction of the winter snow cover history and the winter thermal regime has a complex effect on the duration of the frost cracking window but also on the number of freeze-thaw cycles as shown by a conceptual model. Predicted future warmer and snow-depleted winters in the European Alps will therefore have a complex impact on the potential weathering of alpine rocks by frost action which makes potential weathering predictions difficult. Neglecting rock moisture and rock properties in determining rock weathering limits the usefulness of solely rock temperature data. However, rock temperature data allow getting an estimate about potential weathering by freeze-thaw action which is often substantially more than previously known.

An unconventional depiction of viewpoint in rock art.

PubMed

Pettigrew, Jack; Scott-Virtue, Lee

2015-01-01

Rock art in Africa sometimes takes advantage of three-dimensional features of the rock wall, such as fissures or protuberances, that can be incorporated into the artistic composition (Lewis-Williams, 2002). More commonly, rock artists choose uniform walls on which two-dimensional depictions may represent three-dimensional figures or objects. In this report we present such a two-dimensional depiction in rock art that we think reveals an intention by the artist to represent an unusual three-dimensional viewpoint, namely, with the two human figures facing into the rock wall, instead of the accustomed Western viewpoint facing out!

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

Four LPSA interns test the clay at Bonnie Claire Playa, another location where the rocks move, to see how quickly water is absorbed. Interns, clockwise: Kyle Yawn (standing), Gregory Romine, Emily Kopp, and Clint Naquin. Photo credit: NASA/GSFC/Maggie McAdam To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

The trails can be straight, or they can curve. Sometimes, two trails run alongside each other. Those two lines running from left to right in the back look like they were made by a car; but they were made by rocks. Photo credit: NASA/GSFC/Maggie McAdam To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

Data from the sensors were downloaded, and then the sensors were reburied. The LPSA team plans to publish a research paper that will present their data and offer their explanation for how the rocks move. Photo credit: NASA/GSFC/Maggie McAdam To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Assessment of Mars Exploration Rover Landing Site Predictions

NASA Astrophysics Data System (ADS)

Golombek, M. P.

2005-05-01

Comprehensive analyses of remote sensing data during the 3-year effort to select the Mars Exploration Rover landing sites at Gusev crater and Meridiani Planum correctly predicted the safe and trafficable surfaces explored by the two rovers. Gusev crater was predicted to be a relatively low relief surface that was comparably dusty, but less rocky than the Viking landing sites. Available data for Meridiani Planum indicated a very flat plain composed of basaltic sand to granules and hematite that would look completely unlike any of the existing landing sites with a dark, low albedo surface, little dust and very few rocks. Orbital thermal inertia measurements of 315 J m-2 s-0.5 K-1 at Gusev suggested surfaces dominated by duricrust to cemented soil-like materials or cohesionless sand or granules, which is consistent with observed soil characteristics and measured thermal inertias from the surface. THEMIS thermal inertias along the traverse at Gusev vary from 285 at the landing site to 330 around Bonneville rim and show systematic variations that can be related to the observed increase in rock abundance (5-30%). Meridiani has an orbital bulk inertia of ~200, similar to measured surface inertias that correspond to observed surfaces dominated by 0.2 mm sand size particles. Rock abundance derived from orbital thermal differencing techniques suggested that Meridiani Planum would have very low rock abundance, consistent with the rock free plain traversed by Opportunity. Spirit landed in an 8% orbital rock abundance pixel, consistent with the measured 7% of the surface covered by rocks >0.04 m diameter at the landing site, which is representative of the plains away from craters. The orbital albedo of the Spirit traverse varies from 0.19 to 0.30, consistent with surface measurements in and out of dust devil tracks. Opportunity is the first landing in a low albedo portion of Mars as seen from orbit, which is consistent with the dark, dust-free surface and measured albedos. The close correspondence between surface characteristics inferred from orbital remote sensing data and that found at the landing sites argues that future efforts to select safe landing sites will be successful. Linking the five landing sites to their remote sensing signatures suggests that they span most of the important, likely safe surfaces available for landing on Mars.

Chlorine Abundances in Martian Meteorites

NASA Technical Reports Server (NTRS)

Bogard, D.D.; Garrison, D.H.; Park, J.

2009-01-01

Chlorine measurements made in martian surface rocks by robotic spacecraft typically give Chlorine (Cl) abundances of approximately 0.1-0.8%. In contrast, Cl abundances in martian meteorites appear lower, although data is limited, and martian nakhlites were also subjected to Cl contamination by Mars surface brines. Chlorine abundances reported by one lab for whole rock (WR) samples of Shergotty, ALH77005, and EET79001 range 108-14 ppm, whereas Cl in nakhlites range 73-1900 ppm. Measurements of Cl in various martian weathering phases of nakhlites varied 0.04-4.7% and reveal significant concentration of Cl by martian brines Martian meteorites contain much lower Chlorine than those measured in martian surface rocks and give further confirmation that Cl in these surface rocks was introduced by brines and weathering. It has been argued that Cl is twice as effective as water in lowering the melting point and promoting melting at shallower martian depths, and that significant Cl in the shergottite source region would negate any need for significant water. However, this conclusion was based on experiments that utilized Cl concentrations more analogous to martian surface rocks than to shergottite meteorites, and may not be applicable to shergottites.

Review of Cuttability Indices and A New Rockmass Classification Approach for Selection of Surface Miners

NASA Astrophysics Data System (ADS)

Dey, Kaushik; Ghose, A. K.

2011-09-01

Rock excavation is carried out either by drilling and blasting or using rock-cutting machines like rippers, bucket wheel excavators, surface miners, road headers etc. Economics of mechanised rock excavation by rock-cutting machines largely depends on the achieved production rates. Thus, assessment of the performance (productivity) is important prior to deploying a rock-cutting machine. In doing so, several researchers have classified rockmass in different ways and have developed cuttability indices to correlate machine performance directly. However, most of these indices were developed to assess the performance of road headers/tunnel-boring machines apart from a few that were developed in the earlier days when the ripper was a popular excavating equipment. Presently, around 400 surface miners are in operation around the world amongst which, 105 are in India. Until now, no rockmass classification system is available to assess the performance of surface miners. Surface miners are being deployed largely on trial and error basis or based on the performance charts provided by the manufacturer. In this context, it is logical to establish a suitable cuttability index to predict the performance of surface miners. In this present paper, the existing cuttability indices are reviewed and a new cuttability indexes proposed. A new relationship is also developed to predict the output from surface miners using the proposed cuttability index.

Influences of petrographic parameters on technological properties of greywackes used for crushed stone production

NASA Astrophysics Data System (ADS)

Prikryl, Richard; Cermak, Martin; Krutilova, Katerina

2014-05-01

This study focuses on the influence of petrographic parameters on technological properties of greywackes. These sedimentary rocks make about 27 % of crushed stone market in the Czech Republic. Mainly in Moravia (eastern part of the Czech Republic), greywackes represent almost exclusive high quality aggregate. The behaviour of greywackes varies, however, from quarry to quarry. In this study, we have selected the most important deposits that cover major lithological variation of local greywackes. Studied greywackes were analysed for their petrographic parameters quantitatively (using image analysis of thin sections). The pore space characteristics were determined by using fluorescent dye - epoxy resin impregnated specimens. The studied rocks are composed of subangular and angular quartz grains, lithoclasts (stable rocks: quartzites, and unstable rocks: phylites, metaphylites, siltstones, slates, greywackes, and less frequently acid eruptive rocks), feldspars (orthoclas, microcline, plagioclase), and detrital micas. Detrital and authigenic chlorite has been found as well. The matrix which represents the largest volume of rock-forming components contains a mixture of sericite, chlorite, clay minerals, cements, and clasts in aleuropelitic size. Based on the microscopic examination, all studied rock types were classified as greywacke with fine- to medium-grained massive rock fabric. Only specimen from Bělkovice has shown partly layered structure. Alteration of feldspars and unstable rock fragments represents common feature. Diagenetic features included pressure dissolution of quartz clasts and formation of siliceous and/or calcite cements. Based on the experimental study of technological performance of studied greywackes and its correlation to petrographic features, the average size of clasts and volume of matrix make the driving factors affecting the LA values. The LA values decrease with the increasing of volume of matrix (R = 0.61) and with decreasing average grain size (R = 0.44). The degree of sorting influences LA values as well; more graded greywackes tend to show higher LA values. Regarding PSV, its values increase with increasing volume of quartz clasts.

A new method for automatic discontinuity traces sampling on rock mass 3D model

NASA Astrophysics Data System (ADS)

Umili, G.; Ferrero, A.; Einstein, H. H.

2013-02-01

A new automatic method for discontinuity traces mapping and sampling on a rock mass digital model is described in this work. The implemented procedure allows one to automatically identify discontinuity traces on a Digital Surface Model: traces are detected directly as surface breaklines, by means of maximum and minimum principal curvature values of the vertices that constitute the model surface. Color influence and user errors, that usually characterize the trace mapping on images, are eliminated. Also trace sampling procedures based on circular windows and circular scanlines have been implemented: they are used to infer trace data and to calculate values of mean trace length, expected discontinuity diameter and intensity of rock discontinuities. The method is tested on a case study: results obtained applying the automatic procedure on the DSM of a rock face are compared to those obtained performing a manual sampling on the orthophotograph of the same rock face.

Nanoscale Compositional Relations in Lunar Rock Patina: Deciphering Sources for Patina Components on an Apollo 17 Station 6 Boulder

NASA Technical Reports Server (NTRS)

Christoffersen, R.; Noble, S. K.; Keller, L. P.

2014-01-01

Space weathering on the Moon and other airless bodies modifies the surfaces of regolith grains as well as the space-exposed surfaces of larger rocks and boulders. As space weathering witness plates, rocks and boulders are distinguished from regolith grains based on their ability to persist as physically intact substrates over longer time scales before being disaggregated by impact processes. Because lunar surfaces, including exposed rocks, quickly develop an optically thick layer of patina, it is important to understand the compositional relationship between patinas and their underlying rock substrates, particularly to support remote-sensing of rocky lunar terrains. Based on analytical TEM techniques, supported by focused ion beam (FIB) cross-sectioning, we have begun to systematize the multi-layer microstructural complexity of patinas on rock samples with a range of space exposure histories. Our on-going work has particularly focused on lunar rock 76015, both because it has a long (approx. 22 my) exposure history, and because its surface was exposed to patina development approximately 1 m off the regolith surface on a boulder in the Apollo 17 Station 6 boulder field. Potential sources for the 76015 patina therefore include impact-melted and vaporized material derived from the local rock substrate, as well as from the mix of large boulders and regolith in the Station 6 area. While similar, there are differences in the mineralogy and chemistry of the rocks and regolith at Station 6. We were interested to see if these, or other sources, could be distinguished in the average composition, as well as the compositional nanostratigraphy of the 76015 patina. To date we have acquired a total of 9 TEM FIB cross-sections from the 76015 patina, giving us reasonable confidence of being able to arrive at an integrated average for the patina major element composition based on analytical TEM methods.

Monitoring rock glacier dynamics and ground temperatures in the semiarid Andes (Chile, 30°S)

NASA Astrophysics Data System (ADS)

Brenning, Alexander; Azócar, Guillermo F.; Bodin, Xavier

2013-04-01

Rock glaciers and mountain permafrost are widespread in the high semiarid Andes of Chile, where they concentrate greater amounts of ice than glaciers. Rock glaciers are of particular interest because in some cases the permafrost they contain might be in a degrading in response to climatic warming. This could result in increased dynamics and even to destabilization, which has been observed on some rock glaciers in the studied area. Displacement rates and active-layer temperatures of two rock glaciers as well as ground surface temperatures of the periglacial environment in the upper Elqui valley have been monitored since summer 2009/10 with funding from the Chilean Dirección General de Aguas. Differential GPS measurements of 115 points on the surface of two rock glaciers since April 2010 showed horizontal displacements of up to 1.3 m/a on the Llano de las Liebres rock glacier and up to 1.2 m/a on the Tapado rock glacier. General velocity patterns are consistent with the morphological evidence of activity (e.g., front slopes, looseness of debris) and for the Tapado complex, a clearly distinct activity from the debris-covered glacier was observed. Temperature measurements in four boreholes indicate active-layer depths of about 2.5 m at the highest locations on the Tapado rock glacier (~4400 m a.s.l.) and about 8 m near the front of the Llano rock glacier (3786 m a.s.l.). Spatial patterns of mean ground surface temperature (MGST) were analyzed with regards to influences of elevation, potential incoming solar radiation, location on ice-debris landforms (rock and debris-covered glaciers), and snow cover duration using linear mixed-effects models. While accounting for the other variables, sites with long-lasting snow patches had ~0.4°C lower MGST, and ice-debris landforms had ~0.4-0.6°C lower MGST than general debris surfaces, highlighting important local modifications to the general topographic variation of ground thermal conditions.

Strontium and neodymium isotope systematics of target rocks and impactites from the El'gygytgyn impact structure: Linking impactites and target rocks

NASA Astrophysics Data System (ADS)

Wegner, Wencke; Koeberl, Christian

2016-12-01

The 3.6 Ma El'gygytgyn structure, located in northeastern Russia on the Chukotka Peninsula, is an 18 km diameter complex impact structure. The bedrock is formed by mostly high-silica volcanic rocks of the 87 Ma old Okhotsk-Chukotka Volcanic Belt (OCVB). Volcanic target rocks and impact glasses collected on the surface, as well as drill core samples of bedrock and impact breccias have been investigated by thermal ionization mass spectrometry (TIMS) to obtain new insights into the relationships between these lithologies in terms of Nd and Sr isotope systematics. Major and trace element data for impact glasses are added to compare with the composition of target rocks and drill core samples. Sr isotope data are useful tracers of alteration processes and Nd isotopes reveal characteristics of the magmatic sources of the target rocks, impact breccias, and impact glasses. There are three types of target rocks mapped on the surface: mafic volcanics, dacitic tuff and lava of the Koekvun' Formation, and dacitic to rhyolitic ignimbrite of the Pykarvaam Formation. The latter represents the main contributor to the impact rocks. The drill core is divided into a suevite and a bedrock section by the Sr isotope data, for which different postimpact alteration regimes have been detected. Impact glasses from the present-day surface did not suffer postimpact hydrothermal alteration and their data indicate a coherent alteration trend in terms of Sr isotopes with the target rocks from the surface. Surprisingly, the target rocks do not show isotopic coherence with the Central Chukotka segment of the OCVB or with the Berlozhya magmatic assemblage (BMA), a late Jurassic felsic volcanic suite that crops out in the eastern part of the central Chukotka segment of the OCVB. However, concordance for these rocks exists with the Okhotsk segment of the OCVB. This finding argues for variable source magmas having contributed to the build-up of the OCVB.

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

NASA Astrophysics Data System (ADS)

Hartmann, William K.; Barlow, Nadine G.

2006-10-01

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

Young Lunar Volcanic Features: Thermophysical Properties and Formation

NASA Astrophysics Data System (ADS)

Elder, C. M.; Hayne, P. O.; Donaldson Hanna, K. L.; Bandfield, J.; Ghent, R. R.; Williams, J. P.; Paige, D. A.

2016-12-01

Irregular Mare Patches (IMPs) are small features (100 - 5000 m) on the lunar nearside characterized by uneven terrain interspersed with topographically higher smooth terrain. Crater counting suggests that they are less than 100 Myr old [1, 2]. Several formation hypotheses have been proposed for IMPs, including: caldera collapse [3], explosive outgassing [2], lava flow inflation [4], pyroclastic eruption [5], and regolith drainage [6]. In this study, we use thermal infrared data from the Lunar Reconnaissance Orbiter (LRO) Diviner radiometer to investigate the thermophysical properties of the IMPs. We find that their average rock abundance is approximately a factor of two higher than the surrounding terrain. Comparison of Diviner data with thermal models rules out extensive competent rocks within 5-10 cm of the surface at the IMPs. We also derive the regolith thermal inertia [7] of the four largest IMPs. Sosigenes, Maskelyne, and Cauchy-5 have thermal inertias slightly higher than their surrounding terrain, likely due to the presence of small rocks surrounding nearby craters. Ina has an average thermal inertia lower than the surrounding terrain, and the only resolved smooth mound in Ina has an even lower thermal inertia which implies material that is less consolidated than typical regolith and/or contains fewer small rocks. Formation by lava flows or regolith drainage is not expected to result in material with a lower thermal inertia than pre-existing regolith, so in the case of at least Ina, some other process such as explosive outgassing or pyroclastic eruptions must have occurred. [1] Braden, S. et al. (2014) Nature Geo 7, 787-791. [2] Schultz, P. H. et al. (2006) Nature 444, 184-186. [3] El-Baz, F. (1973) Apollo 17: Preliminary Science Report 330, 30-13. [4] Garry, W. B. et al. (2012) JGR 117, E00H31. [5] Carter, L. B. et al. (2013) LPSC 44, 2146. [6] Qiao, L. et al. (2002) LPSC 47, 2002. [7] Vasavada, A. R. et al. (2012) JGR 117, E00H18.

30 CFR 57.3203 - Rock fixtures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Rock fixtures. 57.3203 Section 57.3203 Mineral... Support-Surface and Underground § 57.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall...

30 CFR 57.3203 - Rock fixtures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Rock fixtures. 57.3203 Section 57.3203 Mineral... Support-Surface and Underground § 57.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall...

30 CFR 57.3203 - Rock fixtures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Rock fixtures. 57.3203 Section 57.3203 Mineral... Support-Surface and Underground § 57.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall...

Alteration Mineralogy of Adirondack-class Rocks in Gusev Crater, Mars

NASA Astrophysics Data System (ADS)

Hamilton, V. E.; Ruff, S. W.

2009-12-01

The rock Adirondack is the type example of a class of basaltic rocks analyzed by the Mars Exploration Rover Spirit in Gusev crater. Thermal infrared spectra of Adirondack-class rocks acquired by the Mini-TES instrument are distinguishable from spectra of other rock classes by the presence of an emissivity peak at 430 cm-1 and a minimum near 510 cm-1, which are characteristic of olivine. This is the primary spectral class on the plains of Gusev, but spectra of rocks exhibiting similar low wavenumber spectral character have been acquired along the rover traverse in the Columbia Hills, and we have confirmed that these also are Adirondack-class. Linear mixture modeling of their infrared spectra (enabled by applying a correction for dust on the Mini-TES optics) suggests that they are mafic with sulfate minerals present as alteration phases (up to 25%) in the majority of these rocks, broadly consistent with APXS-measured chemistry. The RAT-brushed surface of an unusual plains rock referred to as Mazatzal exhibits a spectral shape and modeled mineralogy consistent with the absence of olivine and the presence of amorphous phases low in silica, and is a coating unlike any other observed on Mars. We have also used a previously-demonstrated factor analysis and target transformation (FATT) technique with Adirondack-class rock spectra to retrieve the spectral shapes of independently-varying components within the data set. Using this approach, we have identified four shapes attributable to two distinct surface components, fine particulate surface dust, and a second dust component similar to downwelling sky radiance and/or dust on the Mini-TES optics. The two surface shapes do not resemble those of the two canonical surface types measured from orbit. One of the surface shapes is very similar to that of the lherzolitic Shergottite ALH A77005. Preliminary linear mixture analysis of this shape shows that it is dominated by olivine (~57%, ~Fo45) and pyroxene (~28%), with minor amounts of oxides and basaltic glass (~15%). This ultramafic composition is similar to that derived from linear mixture modeling of the measured Mini-TES spectra, but differs in detail from the APXS-derived normative mineralogy and Mössbauer ol:px. These differences may be artifacts of the penetration depths and spot sizes of the measurements, or assumptions inherent in the conversions from chemistry and spectra to norms and abundances; work in progress is aimed at explaining these differences. The other shape is modeled with high-silica phases (29%), sulfates (~24%), olivine (~19%), pyroxene (~15%), and oxides (~12%), suggesting it represents a highly altered mineralogy. We linearly modeled the highest-quality measured spectra of Adirondack-class rocks using only the FATT-derived spectral shapes. Surface components are modeled by varying proportions of the two surface shapes, with all containing ≥40% of the ultramafic shape. These preliminary results suggest that Adirondack-class rocks are a single lithology exhibiting sulfate-bearing surface alteration that is variable from rock to rock. We are in the process of converting the mineralogies derived from measured and FATT-derived spectra into bulk oxides and will present quantitative comparisons with APXS data and qualitative comparisons with Mössbauer data.

Continuous Monitoring of Pin Tip Wear and Penetration into Rock Surface Using a New Cerchar Abrasivity Testing Device

NASA Astrophysics Data System (ADS)

Hamzaban, Mohammad-Taghi; Memarian, Hossein; Rostami, Jamal

2014-03-01

Evaluation of rock abrasivity is important when utilizing mechanized excavation in various mining and civil projects in hard rock. This is due to the need for proper selection of the rock cutting tools, estimation of the tool wear, machine downtime for cutter change, and costs. The Cerchar Abrasion Index (CAI) test is one of the simplest and most widely used methods for evaluating rock abrasivity. In this study, a new device for the determination of frictional forces and depth of pin penetration into the rock surface during a Cerchar test is discussed. The measured parameters were used to develop an analytical model for calculation of the size of the wear flat (and hence a continuous measure of CAI as the pin moves over the sample) and pin tip penetration into the rock during the test. Based on this model, continuous curves of CAI changes and pin tip penetration into the rock were plotted. Results of the model were used for introduction of a new parameter describing rock-pin interaction and classification of rock abrasion.

Modeling the growth and interaction of stylolite networks, using the discrete element method for pressure solution

NASA Astrophysics Data System (ADS)

Makedonska, N.; Sparks, D. W.; Aharonov, E.

2012-12-01

Pressure solution (also termed chemical compaction) is considered the most important ductile deformation mechanism operating in the Earth's upper crust. This mechanism is a major player in a variety of geological processes, including evolution of sedimentary basins, hydrocarbon reservoirs, aquifers, earthquake recurrence cycles, and fault healing. Pressure solution in massive rocks often localizes into solution seams or stylolites. Field observations of stylolites often show elastic/brittle interactions in regions between pressure solution features, including and shear fractures, veins and pull-apart features. To understand these interactions, we use a grain-scale model based on the Discrete Element Method that allows granular dissolution at stressed contacts between grains. The new model captures both the slow chemical compaction process and the more abrupt brittle fracturing and sliding between grains. We simulate a sample of rock as a collection of particles, each representing either a grain or a unit of rock, bonded to each other with breakable cement. We apply external stresses to this sample, and calculate elastic and frictional interactions between the grains. Dissolution is modeled by an irreversible penetration of contacting grains into each other at a rate that depends on the contact stress and an adjustable rate constant. Experiments have shown that dissolution rates at grain contacts are greatly enhanced when there is a mineralogical contrast. Therefore, we dissolution rate constant can be increased to account for an amount of impurities (e.g. clay in a quartz or calcite sandstone) that can accumulate on dissolving contacts. This approach allows large compaction and shear strains within the rock, while allowing examination of local grain-scale heterogeneity. For example, we will describe the effect of pressure solution on the distribution of contact forces magnitudes and orientations. Contact forces in elastic granular packings are inherently heteregeneous, but stress-dependent dissolution tends to equalize them. We apply our model to the simulation of stylolite networks, particularly the interaction of stylolite tips. The stress concentrations from these tips are transmitted through the intervening rock, which can cause elastic strain, brittle damage and frictional sliding. Our model shows that grain rearrangement and compaction rate depend on the surface friction coefficient of grains. Simulation results show the development of shear zones between stylolites, and a high porosity process zone at the tips of stylolites. These features, which have been observed in field studies, are modeled and predicted for the first time. This modeling tool holds a promise to provide many new insights regarding the coupling between pressure solution and brittle deformation, i.e. between mechanical and chemical compaction.

Selective adsorption of L- and D-amino acids on calcite: Implications for biochemical homochirality

NASA Technical Reports Server (NTRS)

Hazen, R. M.; Filley, T. R.; Goodfriend, G. A.

2001-01-01

The emergence of biochemical homochirality was a key step in the origin of life, yet prebiotic mechanisms for chiral separation are not well constrained. Here we demonstrate a geochemically plausible scenario for chiral separation of amino acids by adsorption on mineral surfaces. Crystals of the common rock-forming mineral calcite (CaCO(3)), when immersed in a racemic aspartic acid solution, display significant adsorption and chiral selectivity of d- and l-enantiomers on pairs of mirror-related crystal-growth surfaces. This selective adsorption is greater on crystals with terraced surface textures, which indicates that d- and l-aspartic acid concentrate along step-like linear growth features. Thus, selective adsorption of linear arrays of d- and l-amino acids on calcite, with subsequent condensation polymerization, represents a plausible geochemical mechanism for the production of homochiral polypeptides on the prebiotic Earth.

Lithologic mapping of silicate rocks using TIMS

NASA Technical Reports Server (NTRS)

Gillespie, A. R.

1986-01-01

Common rock-forming minerals have thermal infrared spectral features that are measured in the laboratory to infer composition. An airborne Daedalus scanner (TIMS) that collects six channels of thermal infrared radiance data (8 to 12 microns), may be used to measure these same features for rock identification. Previously, false-color composite pictures made from channels 1, 3, and 5 and emittance spectra for small areas on these images were used to make lithologic maps. Central wavelength, standard deviation, and amplitude of normal curves regressed on the emittance spectra are related to compositional information for crystalline igneous silicate rocks. As expected, the central wavelength varies systematically with silica content and with modal quartz content. Standard deviation is less sensitive to compositional changes, but large values may result from mixed admixture of vegetation. Compression of the six TIMS channels to three image channels made from the regressed parameters may be effective in improving geologic mapping from TIMS data, and these synthetic images may form a basis for the remote assessment of rock composition.

Exhumation and topographic evolution of the Namche Barwa Syntaxis, eastern Himalaya

NASA Astrophysics Data System (ADS)

Yang, Rong; Herman, Frédéric; Fellin, Maria Giuditta; Maden, Colin

2018-01-01

The Namche Barwa Syntaxis, as one of the most tectonically active regions, remains an appropriate place to explore the relationship between tectonics, surface processes, and landscape evolution. Two leading models have been proposed for the formation and evolution of this syntaxis, including the tectonic aneurysm model and the syntaxis expansion model. Here we use a multi-disciplinary approach based on low-temperature thermochronometry, numerical modeling, river profile and topographic analyses to investigate the interactions between tectonics, erosion, and landscape evolution and to test these models. Our results emphasize the presence of young cooling ages (i.e., < 1 Ma) along the Parlung River, to the north of the syntaxis. Using numerical modeling we argue that a recent increase in exhumation rate is required to expose these young ages. Our river analysis reveals spatial variations in channel steepness, which we interpret to reflect the rock uplift pattern. By establishing the relationship between erosion rates and topographic features, we find that erosion rates are poorly to weakly correlated with topographic features, suggesting that the landscape is still evolving. Altogether, these results seem better explained by a mechanism that involves a northward expansion of the syntaxis, which causes high rock uplift rates to the north of the syntaxis and a transient state of topography adjusting to an evolving tectonic setting.

The influence of geology and land use on arsenic in stream sediments and ground waters in New England, USA

USGS Publications Warehouse

Robinson, G.R.; Ayotte, J.D.

2006-01-01

Population statistics for As concentrations in rocks, sediments and ground water differ by geology and land use features in the New England region, USA. Significant sources of As in the surficial environment include both natural weathering of rocks and anthropogenic sources such as arsenical pesticides that were commonly applied to apple, blueberry and potato crops during the first half of the 20th century in the region. The variation of As in bedrock ground water wells has a strong positive correlation with geologic features at the geologic province, lithology group, and bedrock map unit levels. The variation of As in bedrock ground water wells also has a positive correlation with elevated stream sediment and rock As chemistry. Elevated As concentrations in bedrock wells do not correlate with past agricultural areas that used arsenical pesticides on crops. Stream sediments, which integrate both natural and anthropogenic sources, have a strong positive correlation of As concentrations with rock chemistry, geologic provinces and ground water chemistry, and a weaker positive correlation with past agricultural land use. Although correlation is not sufficient to demonstrate cause-and-effect, the statistics favor rock-based As as the dominant regional source of the element in stream sediments and ground water in New England. The distribution of bedrock geology features at the geologic province, lithology group and map unit level closely correlate with areas of elevated As in ground water, stream sediments, and rocks. ?? 2006 Elsevier Ltd. All rights reserved.

Sagan Lecture: Spirit, Opportunity, and the Exploration of the Red Planet

NASA Astrophysics Data System (ADS)

Squyres, S.

2005-12-01

In January of 2004, twin robotic explorers named Spirit and Opportunity landed on Mars. Expected to last for 90 days, the two rovers have now been exploring the martian surface for more than a year and a half. Their objective is to search for evidence of past water on Mars, and to determine if Mars ever had conditions that would have been suitable for life. Spirit landed in Gusev Crater, a large impact crater in the southern highlands of Mars. Finding only basaltic lava on the crater floor, Spirit drove almost three kilometers to the base of the Columbia Hills, a small mountain range to the east of the landing site. There Spirit has ascended Husband Hill, the highest summit in the range, and has found strong evidence that the rocks there were modified long ago by water. Opportunity landed on Meridiani Planum, a smooth plateau near the martian equator, coming to rest in a small impact feature named Eagle Crater. Within Eagle Crater, Opportunity found compelling evidence for long-ago water on Mars. This evidence included 'blueberries': small concretions rich in hematite that precipitated from liquid water. It also included rocks that are made largely of sulfate salts, deposited when water evaporated away, and rocks that preserve ancient ripples that formed billions of years ago as water flowed over sand on Mars. The conditions long ago at Eagle Crater may have been suitable for some simple forms of life. Whether life could have developed there, however, is a much more difficult question. After leaving Eagle Crater, Opportunity drove eastward to Endurance Crater, a much larger crater that allowed access to deeper and older rocks which also proved to be blueberry-laden sulfate-rich sediments. Since leaving Endurance Crater, Opportunity has explored southward, driving more than five kilometers across the martian surface. The talk will provide an up-to-date summary of the mission of Spirit and Opportunity, from their initial conception through their launch, landing, and operations on the surface of Mars.

Cenozoic landforms and post-orogenic landscape evolution of the Balkanide orogen: Evidence for alternatives to the tectonic denudation narrative in southern Bulgaria

NASA Astrophysics Data System (ADS)

Gunnell, Y.; Calvet, M.; Meyer, B.; Pinna-Jamme, R.; Bour, I.; Gautheron, C.; Carter, A.; Dimitrov, D.

2017-01-01

Continental denudation is the mass transfer of rock from source areas to sedimentary depocentres, and is typically the result of Earth surface processes. However, a process known as tectonic denudation is also understood to expose deep-seated rocks in short periods of geological time by displacing large masses of continental crust along shallow-angle faults, and without requiring major contributions from surface erosion. Some parts of the world, such as the Basin and Range in the USA or the Aegean province in Europe, have been showcased for their Cenozoic tectonic denudation features, commonly described as metamorphic core-complexes or as supradetachment faults. Based on 22 new apatite fission-track (AFT) and 21 helium (AHe) cooling ages among rock samples collected widely from plateau summits and their adjacent valley floors, and elaborating on inconsistencies between the regional stratigraphic, topographic and denudational records, this study frames a revised perspective on the prevailing tectonic denudation narrative for southern Bulgaria. We conclude that conspicuous landforms in this region, such as erosion surfaces on basement-cored mountain ranges, are not primarily the result of Paleogene to Neogene core-complex formation. They result instead from "ordinary" erosion-driven, subaerial denudation. Rock cooling, each time suggesting at least 2 km of crustal denudation, has exposed shallow Paleogene granitic plutons and documents a 3-stage wave of erosional denudation which progressed from north to south during the Middle Eocene, Oligocene, Early to Middle Miocene, and Late Miocene. Denudation initially prevailed during the Paleogene under a syn-orogenic compressional regime involving piggyback extensional basins (Phase 1), but subsequently migrated southward in response to post-orogenic upper-plate extension driven by trench rollback of the Hellenic subduction slab (Phase 2). Rare insight given by the denudation pattern indicates that trench rollback progressed at a mean velocity of 3 to 4 km/Ma. The Neogene horst-and-graben mosaic that defines the modern landscape (Phase 3) has completely overprinted the earlier fabrics of Phases 1 and 2, and has been the prime focus of tectonic geomorphologists working in the region. The new narrative proposed here for linking the geodynamic evolution of SE Europe with surface landform assemblages raises issues in favour of better documenting the regional sedimentary record of existing Paleogene basins, which constitute a poorly documented missing link to the thermochronological evidence presented here.

Fault rock mineralogy and fluid flow in the Coso Geothermal Field, CA

NASA Astrophysics Data System (ADS)

Davatzes, N. C.; Hickman, S. H.

2005-12-01

The minerals that comprise fault rock, their grain shapes, and packing geometry are important controls on fault zone properties such as permeability, frictional strength, and slip behavior. In this study we examine the role of mineralogy and deformation microstructures on fluid flow in a fault-hosted, fracture-dominated geothermal system contained in granitic rocks in the Coso Geothermal Field, CA. Initial examination of the mineralogy and microstructure of fault rock obtained from core and surface outcrops reveals three fault rock types. (1) Fault rock consisting of kaolinite and amorphous silica that contains large connected pores, dilatant brittle fractures, and dissolution textures. (2) Fault rock consisting of foliated layers of chlorite and illite-smectite separated by slip surfaces. (3) Fault rock consisting of poorly sorted angular grains, characterized by large variations in grain packing (pore size), and crack-seal textures. These different fault rocks are respectively associated with a high permeability upper boiling zone for the geothermal system, a conductively heated "caprock" at moderate to shallow depth associated with low permeability, and a deeper convectively heated region associated with enhanced permeability. Outcrop and hand-sample scale mapping, XRD analysis, and SEM secondary electron images of fault gouge and slip surfaces at different stages of development (estimated shear strain) are used to investigate the processes responsible for the development and physical properties of these distinct fault rocks. In each type of fault rock, mineral dissolution and re-precipitation in conjunction with the amount and geometry of porosity changes induced by dilation or compaction are the key controls on fault rock development. In addition, at the contacts between slip surfaces, abrasion and resulting comminution appear to influence grain size, sorting, and packing. Macroscopically, we expect the frictional strength of these characteristic fault rocks to differ because the processes that accommodate deformation depend strongly on mineralogy. Frictional strength of quartz-dominated fault rocks in the near surface and in the reservoir should be greater (~0.6) than that in the clay-dominated cap rock (~0.2-0.4). Similarly, permeability should be much lower in foliated clay-rich fault rocks than in quartz-rich fault rocks as evidenced by larger, more connected pores imaged in quartz-rich gouge. Mineral stability is a function of loading, strain rate, temperature, and fluid flow conditions. Which minerals form, and the rates at which they grow is also a key element in determining variations in the magnitude and anisotropy of fault zone properties at Coso. Consequently, we suggest that the development of fault-zone properties depends on the feedback between deformation, resulting changes in permeability, and large-scale fluid flow and the leading to dissolution/precipitation of minerals in the fault rock and adjacent host rock. The implication for Coso is that chemical alteration of otherwise low-porosity crystalline rocks appears to determine the distribution and temporal evolution of permeability in the actively deforming fracture network at small to moderate scales as well as along major, reservoir-penetrating fault zones.

C-band RISAT-1 imagery for geospatial mapping of cryospheric surface features in the Antarctic environment

NASA Astrophysics Data System (ADS)

Jawak, Shridhar D.; Panditrao, Satej N.; Luis, Alvarinho J.

2016-05-01

Cryospheric surface feature classification is one of the widely used applications in the field of polar remote sensing. Precise surface feature maps derived from remotely sensed imageries are the major requirement for many geoscientific applications in polar regions. The present study explores the capabilities of C-band dual polarimetric (HH & HV) SAR imagery from Indian Radar Imaging Satellite (RISAT-1) for land cryospheric surface feature mapping. The study areas selected for the present task were Larsemann Hills and Schirmacher Oasis, East Antarctica. RISAT-1 Fine Resolution STRIPMAP (FRS-1) mode data with 3-m spatial resolution was used in the present research attempt. In order to provide additional context to the amount of information in dual polarized RISAT-1 SAR data, a band HH+HV was introduced to make use of the original two polarizations. In addition to the data calibration, transformed divergence (TD) procedure was performed for class separability analysis to evaluate the quality of the statistics before image classification. For most of the class pairs the TD values were comparable, which indicated that the classes have good separability. Fuzzy and Artificial Neural Network classifiers were implemented and accuracy was checked. Nonparametric classifier Support Vector Machine (SVM) was also used to classify RISAT-1 data with an optimized polarization combination into three land-cover classes consisting of sea ice/snow/ice, rocks/landmass, and lakes/waterbodies. This study demonstrates that C-band FRS1 image mode data from the RISAT-1 mission can be exploited to identify, map and monitor land cover features in the polar regions, even during dark winter period. For better landcover classification and analysis, hybrid polarimetric data (cFRS-1 mode) from RISAT-1, which incorporates phase information, unlike the dual-pol linear (HH, HV) can be used for obtaining better polarization signatures.

In vitro receptivity of carbonate rocks to endolithic lichen-forming aposymbionts.

PubMed

Favero-Longo, Sergio E; Borghi, Alessandro; Tretiach, Mauro; Piervittori, Rosanna

2009-10-01

Sterile cultured isolates of lichen-forming aposymbionts have not yet been used to investigate lichen-rock interactions under controlled conditions. In this study mycobionts and photobiont of the endolithic lichens Bagliettoa baldensis and Bagliettoa marmorea were isolated and inoculated with coupons of one limestone and four marbles commonly employed in the Cultural Heritage framework. After one year of incubation, microscopic observations of polished cross-sections were performed to verify if the typical colonization patterns observed in the field may be reproduced in vitro and to evaluate the receptivity of the five lithotypes to endolithic lichens. The mycobionts of the two species developed both on the surface of and within all the lithotypes, showing different penetration pathways which depend on mineralogical and structural features and highlight different receptivity. By contrast, algae inoculated with the coupons did not penetrate them. Observations suggest that the hyphal penetration along intrinsic discontinuities of rocks is a relatively fast phenomenon when these organisms are generally considered as slow-growing. Samples from limestone outcrops and abandoned marble quarries, colonized by the same species or other representatives of Verrucariaceae, showed penetration pathways intriguingly similar to those reproduced in vitro and highlighted that lichen-driven erosion processes only increase the availability of hyphal passageways after a long-term colonization. These results show that in vitro incubation of sterile cultured lichen-forming ascomycetes with rock coupons is a practicable experimental system to investigate the lichen-rock interactions under controlled conditions and, together with analysis in situ, may support decisions on conservative treatments of historical and cultural significant stone substrata.

Geophysical Signatures of Shear-Induced Damage and Frictional Processes on Rock Joints

NASA Astrophysics Data System (ADS)

Hedayat, Ahmadreza; Haeri, Hadi; Hinton, John; Masoumi, Hossein; Spagnoli, Giovanni

2018-02-01

In this study, ultrasonic waves recorded during direct shear experiments on rock joints were employed to investigate the shear failure processes. Three types of wave attributes were systematically observed prior to the shear failure of the rock joints: (a) maximum in the amplitude of the transmitted wave, (b) maximum in the dominant frequency of the transmitted wave, and (c) maximum in the velocity of the wave. Different processes occurring during both frictional sliding and stick-slip oscillations were identified in this study: (a) interseismic phase and (b) preseismic phase. The interseismic phase is associated with elastic loading, very small local slip rate, and increasing ultrasonic transmission along the contact surfaces. The rock joint is considered locked, and the increase in ultrasonic transmission represents an increase in the real (true) area of contact because of interlocking and contact aging. The start of the preseismic phase is marked by the onset of precursors for different regions of the rock joint. Following the interseismic and preseismic phases, coseismic phase occurs. The coseismic phase begins with the reduction in the applied shear stress and is associated with an abrupt increase in the local slip rate. The reductions in transmitted amplitude, wave velocity, and dominant frequency all indicate the preseismic phase when the asperity contacts begin to fail before macroscopic frictional sliding. The observation of the preseismic phase in both the loading phase leading to stable sliding and stick-slip failure modes suggests that microphysical processes of fault weakening may share key features for these two failure modes.

ARC-1979-A79-7016

NASA Image and Video Library

1979-03-01

Range : 4.2 million kilometers (2.6 million miles) Ganymede is Jupiter's Largest Galilean satellites and 3rd from the planet. Photo taken after midnight Ganymede is slightly larger than Mercury but much less dense (twice the density of water). Its surface brightness is 4 times of Earth's Moon. Mare regions (dark features) are like the Moon's but have twice the brightness, and believed to be unlikely of rock or lava as the Moon's are. It's north pole seems covered with brighter material and may be water frost. Scattered brighter spots may be related to impact craters or source of fresh ice.

Venus geology, geochemistry, and geophysics - Research results from the USSR

NASA Astrophysics Data System (ADS)

Barsukov, V. L.; Basilevsky, A. T.; Volkov, V. P.; Zharkov, V. N.

The book includes papers on the Venusian volcanism, hot-spot structures, the Lakshmi phenomenon, tesserae, ridge belts on plains, impact craters, evidence on the crustal dichotomy, the global tectonic style, resurfacing, and Venusian igneous rocks. Special attention is given to volatiles in the atmosphere and crust, the expansion of topography into spherical harmonics, rotation, statistical properties of topography and the gravity field, a physical model of Venus, and models of the thermal evolution of Venus. Also presented are an atlas of Venusian surface images and a table listing topographic features on Venus and their coordinates.

Grays Harbor and Chehalis River Improvements to Navigation Environmental Studies. Benthic Invertebrate Studies in Grays Harbor, Washington,

DTIC Science & Technology

1982-04-01

protected from wave action by the jetty, ocean swells were a major environmental feature at the site. In addition, strong tidal currents sweep along thc...2 ) BIOMS j2 SURFACE OF ROCK 1 2Mean 1I Mean Crustacea 0 0 0 0 0 0 Corophium spinicorne 125,758 67,425 96,592 25.432 21.364 23,398 Annelida 0 0 0 0 0...variety of p 127 *I factors, both biotic (e.g., reproductive and distributive patterns of key species) and abiotic (e.g., salinity regimes). The most

Apollo 14 rock samples

NASA Technical Reports Server (NTRS)

Carlson, I. C.

1978-01-01

Petrographic descriptions of all Apollo 14 samples larger than 1 cm in any dimension are presented. The sample description format consists of: (1) an introductory section which includes information on lunar sample location, orientation, and return containers, (2) a section on physical characteristics, which contains the sample mass, dimensions, and a brief description; (3) surface features, including zap pits, cavities, and fractures as seen in binocular view; (4) petrographic description, consisting of a binocular description and, if possible, a thin section description; and (5) a discussion of literature relevant to sample petrology is included for samples which have previously been examined by the scientific community.

ARC-1979-A79-7019

NASA Image and Video Library

1979-02-27

Range : 6 million kilometers (3.7 million miles) Central Longitude 120 degrees west, North is up. and 3rd from the planet. Photo taken after midnight Ganymede is slightly larger than Mercury but much less dense (twice the density of water). Its surface brightness is 4 times of Earth's Moon. Mare regions (dark features) are like the Moon's but have twice the brightness, and believed to be unlikely of rock or lava as the Moon's are. It's north pole seems covered with brighter material and may be water frost. Scattered brighter spots may be related to impact craters or source of fresh ice.

Stress Related Fracturing in Dimension Stone Quarries

NASA Astrophysics Data System (ADS)

Hamdi Deliormanli, Ahmet; Maerz, Norbert H.

2016-10-01

In Missouri, the horizontal stresses (pressures) in the near surface rock are uncommonly high. While the vertical stresses in rock are simply a function of the weight of the overlying rock, near surface stresses can be many times higher. The near surface horizontal stresses can be in excess of 5 times greater than the vertical stresses. In this research, Flatjack method was used to measure horizontal stress in Red Granite Quarry in Missouri. The flat jack method is an approved method of measuring ground stresses. A saw cut is used to “relax” the stress in the ground by allowing the rock to deform inwards the cut. A hydraulic flat jack is used to inflate the slot; to push the rock back to its stressed position, as measured by a strain gauge on either side of the slot. The pressure in the jack, when the rock is exactly back to its original position, is equal to the ground stress before the saw cut was made. According to the results, present production direction for each pit is not good because the maximum stress direction is perpendicular with production direction. This case causes unintentional breakage results in the loss rock. The results show that production direction should be changed.

On the state of stress in the near-surface of the earth's crust

USGS Publications Warehouse

Savage, W.Z.; Swolfs, H.S.; Amadei, B.

1992-01-01

Five models for near-surface crustal stresses induced by gravity and horizontal deformation and the influence of rock property contrasts, rock strength, and stress relaxation on these stresses are presented. Three of the models-the lateral constraint model, the model for crustal stresses caused by horizontal deformation, and the model for the effects of anisotropy-are linearly elastic. The other two models assume that crustal rocks are brittle or viscoelastic in order to account for the effects of rock strength and time on near-surface stresses. It is shown that the lateral constraint model is simply a special case of the combined gravity-and deformation-induced stress field when horizontal strains vanish and that the inclusion of the effect of rock anisotropy in the solution for crustal stresses caused by gravity and horizontal deformation broadens the range for predicted stresses. It is also shown that when stress levels in the crust reach the limits of brittle rock strength, these stresses become independent of strain rates and that stress relaxation in ductile crustal rocks subject to constant horizontal strain rates causes horizontal stresses to become independent of time in the long term. ?? 1992 Birkha??user Verlag.

The Rock Cycle

ERIC Educational Resources Information Center

Singh, Raman J.; Bushee, Jonathan

1977-01-01

Presents a rock cycle diagram suitable for use at the secondary or introductory college levels which separates rocks formed on and below the surface, includes organic materials, and separates products from processes. (SL)

Observations, models, and mechanisms of failure of surface rocks surrounding planetary surface loads

NASA Technical Reports Server (NTRS)

Schultz, R. A.; Zuber, M. T.

1994-01-01

Geophysical models of flexural stresses in an elastic lithosphere due to an axisymmetric surface load typically predict a transition with increased distance from the center of the load of radial thrust faults to strike-slip faults to concentric normal faults. These model predictions are in conflict with the absence of annular zones of strike-slip faults around prominent loads such as lunar maria, Martian volcanoes, and the Martian Tharsis rise. We suggest that this paradox arises from difficulties in relating failure criteria for brittle rocks to the stress models. Indications that model stresses are inappropriate for use in fault-type prediction include (1) tensile principal stresses larger than realistic values of rock tensile strength, and/or (2) stress differences significantly larger than those allowed by rock-strength criteria. Predictions of surface faulting that are consistent with observations can be obtained instead by using tensile and shear failure criteria, along with calculated stress differences and trajectories, with model stress states not greatly in excess of the maximum allowed by rock fracture criteria.

Study of Dominant Factors Affecting Cerchar Abrasivity Index

NASA Astrophysics Data System (ADS)

Rostami, Jamal; Ghasemi, Amireza; Alavi Gharahbagh, Ehsan; Dogruoz, Cihan; Dahl, Filip

2014-09-01

The Cerchar abrasion index is commonly used to represent rock abrasion for estimation of bit life and wear in various mining and tunneling applications. Although the test is simple and fast, there are some discrepancies in the test results related to the equipment used, condition of the rock surface, operator skills, and procedures used in conducting and measuring the wear surface. This paper focuses on the background of the test and examines the influence of various parameters on Cerchar testing including pin hardness, surface condition of specimens, petrographical and geomechanical properties, test speed, applied load, and method of measuring wear surface. Results of Cerchar tests on a set of rock specimens performed at different laboratories are presented to examine repeatability of the tests. In addition, the preliminary results of testing with a new device as a potential alternative testing system for rock abrasivity measurement are discussed.

Surface complexation modeling of americium sorption onto volcanic tuff.

PubMed

Ding, M; Kelkar, S; Meijer, A

2014-10-01

Results of a surface complexation model (SCM) for americium sorption on volcanic rocks (devitrified and zeolitic tuff) are presented. The model was developed using PHREEQC and based on laboratory data for americium sorption on quartz. Available data for sorption of americium on quartz as a function of pH in dilute groundwater can be modeled with two surface reactions involving an americium sulfate and an americium carbonate complex. It was assumed in applying the model to volcanic rocks from Yucca Mountain, that the surface properties of volcanic rocks can be represented by a quartz surface. Using groundwaters compositionally representative of Yucca Mountain, americium sorption distribution coefficient (Kd, L/Kg) values were calculated as function of pH. These Kd values are close to the experimentally determined Kd values for americium sorption on volcanic rocks, decreasing with increasing pH in the pH range from 7 to 9. The surface complexation constants, derived in this study, allow prediction of sorption of americium in a natural complex system, taking into account the inherent uncertainty associated with geochemical conditions that occur along transport pathways. Published by Elsevier Ltd.

Study of borehole probing methods to improve the ground characterization

NASA Astrophysics Data System (ADS)

Naeimipour, Ali

Collecting geological information allows for optimizing ground control measures in underground structures. This includes understanding of the joints and discontinuities and rock strength to develop rock mass classifications. An ideal approach to collect such information is through correlating the drilling data from the roofbolters to assess rock strength and void location and properties. The current instrumented roofbolters are capable of providing some information on these properties but not fully developed for accurate ground characterization. To enhance existing systems additional instrumentation and testing was conducted in laboratory and field conditions. However, to define the geology along the boreholes, the use of probing was deemed to be most efficient approach for locating joints and structures in the ground and evaluation of rock strength. Therefore, this research focuses on selection and evaluation of proper borehole probes that can offer a reliable assessment of rock mass structure and rock strength. In particular, attention was paid to borehole televiewer to characterize rock mass structures and joints and development of mechanical rock scratcher for determination of rock strength. Rock bolt boreholes are commonly drilled in the ribs and the roof of underground environments. They are often small (about 1.5 inches) and short (mostly 2-3 meter). Most of them are oriented upward and thus, mostly dry or perhaps wet but not filled with water. No suitable system is available for probing in such conditions to identify the voids/joints and specifically to measure rock strength for evaluation of rock mass and related optimization of ground support design. A preliminary scan of available borehole probes proved that the best options for evaluation of rock structure is through analysis of borehole images, captured by optical televiewers. Laboratory and field trials with showed that these systems can be used to facilitate measurement of the location, frequency and partially condition of discontinuities. Two of the more promising tools have been tested during this project, which are QL40OBI Optical TV and Slim Borehole Scanner (SBS) manufacture by ALT-Mount Sopris and DMT, respectively. The field experiment with QL40OBI showed that the images generated for downward and sub-horizontal boreholes are of good quality and can be used to evaluate the joint conditions. However, this device is not suitable for use inside the upward drillholes. The Slim Borehole Scanner (SBS) manufactured by DMT in Germany has the required features for borescoping the roofbolt holes. This includes the ease of operation and suitable geometry along with an unwrapped 360-degree picture of the borehole wall. This instrument was concluded to be the best option yet for obtaining images from boreholes with any arbitrary orientation. In addition, a new tool, called Rock Strength Borehole Probe (RSBP), was developed for estimation of the rock strength through scratching the rock surface in the borehole. This device is designed to be a light, flexible, quick, non-disruptive, and cost effective alternative to estimate the rock strength inside the boreholes in underground mines and tunnels. An extensive number of laboratory tests under variable conditions were conducted to develop equations to estimate the Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) of the rock from measured cutting forces. In these experiments, 27 different rock types were tested by full scale scratch tests, including the cutting tests by a miniature disc. The results show a good correlation between the normal force and the compressive strength of sedimentary/metamorphic rock if the depth of scratch is known. No significant correlation was observed for igneous rocks, due to the impacts of grain size. Current studies show promising results for using RSBP. The laboratory and field tests proved the functionality of this tool. This probe is capable of entering boreholes of 45 mm (1¾ in) diameter in any direction and create a groove on the walls and by measurement of the location and cutting forces, estimate rock strength. Additional testing in various underground operations are needed for fine tune the operational features of this probe and make it more accurate. The combination of rock strength and joint conditions will allow for development of rock mass classification that could be used for 3D imaging of the ground conditions around an underground opening as well as hazard maps for the roof.

Method and apparatus for determining two-phase flow in rock fracture

DOEpatents

Persoff, Peter; Pruess, Karsten; Myer, Larry

1994-01-01

An improved method and apparatus as disclosed for measuring the permeability of multiple phases through a rock fracture. The improvement in the method comprises delivering the respective phases through manifolds to uniformly deliver and collect the respective phases to and from opposite edges of the rock fracture in a distributed manner across the edge of the fracture. The improved apparatus comprises first and second manifolds comprising bores extending within porous blocks parallel to the rock fracture for distributing and collecting the wetting phase to and from surfaces of the porous blocks, which respectively face the opposite edges of the rock fracture. The improved apparatus further comprises other manifolds in the form of plenums located adjacent the respective porous blocks for uniform delivery of the non-wetting phase to parallel grooves disposed on the respective surfaces of the porous blocks facing the opposite edges of the rock fracture and generally perpendicular to the rock fracture.

Potential Geological Significations of Crisium Basin Revealed by CE-2 Celms Data

NASA Astrophysics Data System (ADS)

Meng, Z.; Wang, H.; Li, X.; Wang, T.; Cai, Z.; Ping, J.; Fu, Z.

2018-04-01

Mare Crisium is one of the most prominent multi-ring basins on the nearside of the Moon. In this study, the regolith thermophysical features of Mare Crisium are studied with the CELMS data from CE-2 satellite. Several important results are as follows. Firstly, the current geological interpretation only by optical data is not enough, and a new geological perspective is provided. Secondly, the analysis of the low TB anomaly combined with the (FeO+TiO2) abundance and Rock abundance suggests a special unknown material in shallow layer of the Moon surface. At last, a new basaltic volcanism is presented for Crisium Basin. The study hints the potential significance of the CELMS data in understanding the geological units over the Moon surface.

Investigating Long-term Behavior of Outlet Glaciers in Greenland

NASA Technical Reports Server (NTRS)

Csatho, Beata; vanderVeen, Kees; Schenk, Toni

2005-01-01

Repeat surveys by airborne laser altimetry in the 1990s have revealed significant thinning of outlet glaciers draining the interior of the Greenland Ice Sheet, with thinning rates up to several meters per year. To fully appreciate the significance of these recent glacier changes, the magnitude of retreat and surface lowering must be placed within the broader context of the retreat since the Last Glacial Maximum and, more significantly, of the retreat following the temporary glacier advance during the Little Ice Age (LIA). The LIA maximum stand is marked by trimlines, sharp boundaries between recently deglacifated unvegetated rocks, and vegetated surfaces at higher elevations. The objective of this project was to demonstrate the use of remote sensing data to map these trimlines and other glacial geomorphologic features.

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

PubMed

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

2017-05-01

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

Correlation of Rock Spectra with Quantitative Morphologic Indices: Evidence for a Single Rock Type at the Mars Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

Yingst, R. A.; Biedermann, K. L.; Pierre, N. M.; Haldemann, A. F. C.; Johnson, J. R.

2005-01-01

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 (IMP) visible/near-infrared data, efforts in isolating and classifying spectral units among MPF rocks and soils have met with varying degrees of success, as many factors influencing spectral signatures cannot be quantified to a sufficient level to be removed. It has not been fully determined which spectral categories 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 rock mineralogies difficult. Morphology, like composition, is a characteristic tied to the intrinsic properties and geologic and weathering history of rocks. Rock morphologies can be assessed quantitatively and compared with spectral data, to identify and classify rock types at the MPF landing site. They can also isolate actual rock spectra from spectral types that are surficial in origin, as compositions associated with mantling dust or chemical coatings would presumably not influence rock morphology during weathering events. We previously reported on an initial classification of rocks using the quantitative morphologic indices of size, roundness, sphericity and elongation. Here, we compare this database of rock characteristics with associated rock surface spectra to improve our ability to discriminate between spectra associated with rock types and those from other sources.

Compositions of Spherules and Rock Surfaces at Meridiani

NASA Technical Reports Server (NTRS)

Mittlefehldt, David W.; Jolliff, B. L.; Clark, B. C.; Gellert, R.

2007-01-01

The Alpha Particle X-ray Spectrometers (APXS) on the Mars Exploration Rovers (MER) have proven extremely valuable for analyzing rocks and soils on the surface of Mars. The precision of their compositional measurements has been shown to be phenomenal through analyses of the compositionally very uniform Meridiani soils. Through combined use of the rock abrasion tool (RAT) and the analytical instruments on the in-situ deployment device (IDD), analyses of the interiors of fine-grained and texturally uniform rocks with surfaces ground flat have been made under conditions that are nearly ideal for this mode of analysis. The APXS has also been used frequently to analyze materials whose characteristics, surface morphologies, and sample-detector geometries are less than ideal, but the analyses of which are nonetheless very useful for understanding the makeup of the target materials. Such targets include undisturbed rocks with irregular and sometimes coated surfaces and mixed targets such as soils that include fine-grained components as well as coarse grains and pieces of rocks. Such target materials include the well known hematite-rich concretions, referred to as blueberries because of their multispectral color, size, and mode of occurrence. In addition to non-ideal target geometry, such mixed materials also present a heterogeneous target in terms of density. These irregularities violate the assumptions commonly associated with analyses done in the laboratory to achieve the highest possible accuracy. Here we acknowledge the irregularities and we examine the inferences drawn from specific chemical trends obtained on imperfect targets in light of one of the potential pitfalls of natural materials on the surface of Mars, namely thin dust coatings.

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

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

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

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

Archaeal diversity and CO2 fixers in carbonate-/siliciclastic-rock groundwater ecosystems

USGS Publications Warehouse

Lazar, Cassandre Sara; Stoll, Wenke; Lehmann, Robert; Herrmann, Martina; Schwab, Valérie F.; Akob, Denise M.; Nawaz, Ali; Wubet, Tesfaye; Buscot, François; Totsche, Kai-Uwe; Küsel, Kirsten

2017-01-01

Groundwater environments provide habitats for diverse microbial communities, and although Archaea usually represent a minor fraction of communities, they are involved in key biogeochemical cycles. We analysed the archaeal diversity within a mixed carbonate-rock/siliciclastic-rock aquifer system, vertically from surface soils to subsurface groundwater including aquifer and aquitard rocks. Archaeal diversity was also characterized along a monitoring well transect that spanned surface land uses from forest/woodland to grassland and cropland. Sequencing of 16S rRNA genes showed that only a few surface soil-inhabiting Archaea were present in the groundwater suggesting a restricted input from the surface. Dominant groups in the groundwater belonged to the marine group I (MG-I) Thaumarchaeota and the Woesearchaeota. Most of the groups detected in the aquitard and aquifer rock samples belonged to either cultured or predicted lithoautotrophs (e.g., Thaumarchaeota or Hadesarchaea). Furthermore, to target autotrophs, a series of 13CO2 stable isotope-probing experiments were conducted using filter pieces obtained after filtration of 10,000 L of groundwater to concentrate cells. These incubations identified the SAGMCG Thaumarchaeota and Bathyarchaeota as groundwater autotrophs. Overall, the results suggest that the majority of Archaea on rocks are fixing CO2, while archaeal autotrophy seems to be limited in the groundwater.

Archaeal Diversity and CO2 Fixers in Carbonate-/Siliciclastic-Rock Groundwater Ecosystems.

PubMed

Lazar, Cassandre Sara; Stoll, Wenke; Lehmann, Robert; Herrmann, Martina; Schwab, Valérie F; Akob, Denise M; Nawaz, Ali; Wubet, Tesfaye; Buscot, François; Totsche, Kai-Uwe; Küsel, Kirsten

2017-01-01

Groundwater environments provide habitats for diverse microbial communities, and although Archaea usually represent a minor fraction of communities, they are involved in key biogeochemical cycles. We analysed the archaeal diversity within a mixed carbonate-rock/siliciclastic-rock aquifer system, vertically from surface soils to subsurface groundwater including aquifer and aquitard rocks. Archaeal diversity was also characterized along a monitoring well transect that spanned surface land uses from forest/woodland to grassland and cropland. Sequencing of 16S rRNA genes showed that only a few surface soil-inhabiting Archaea were present in the groundwater suggesting a restricted input from the surface. Dominant groups in the groundwater belonged to the marine group I (MG-I) Thaumarchaeota and the Woesearchaeota. Most of the groups detected in the aquitard and aquifer rock samples belonged to either cultured or predicted lithoautotrophs (e.g., Thaumarchaeota or Hadesarchaea). Furthermore, to target autotrophs, a series of 13 CO 2 stable isotope-probing experiments were conducted using filter pieces obtained after filtration of 10,000 L of groundwater to concentrate cells. These incubations identified the SAGMCG Thaumarchaeota and Bathyarchaeota as groundwater autotrophs. Overall, the results suggest that the majority of Archaea on rocks are fixing CO 2 , while archaeal autotrophy seems to be limited in the groundwater.

Archaeal Diversity and CO2 Fixers in Carbonate-/Siliciclastic-Rock Groundwater Ecosystems

PubMed Central

Lazar, Cassandre Sara; Stoll, Wenke; Lehmann, Robert; Herrmann, Martina; Schwab, Valérie F.; Akob, Denise M.; Nawaz, Ali; Wubet, Tesfaye; Buscot, François; Totsche, Kai-Uwe

2017-01-01

Groundwater environments provide habitats for diverse microbial communities, and although Archaea usually represent a minor fraction of communities, they are involved in key biogeochemical cycles. We analysed the archaeal diversity within a mixed carbonate-rock/siliciclastic-rock aquifer system, vertically from surface soils to subsurface groundwater including aquifer and aquitard rocks. Archaeal diversity was also characterized along a monitoring well transect that spanned surface land uses from forest/woodland to grassland and cropland. Sequencing of 16S rRNA genes showed that only a few surface soil-inhabiting Archaea were present in the groundwater suggesting a restricted input from the surface. Dominant groups in the groundwater belonged to the marine group I (MG-I) Thaumarchaeota and the Woesearchaeota. Most of the groups detected in the aquitard and aquifer rock samples belonged to either cultured or predicted lithoautotrophs (e.g., Thaumarchaeota or Hadesarchaea). Furthermore, to target autotrophs, a series of 13CO2 stable isotope-probing experiments were conducted using filter pieces obtained after filtration of 10,000 L of groundwater to concentrate cells. These incubations identified the SAGMCG Thaumarchaeota and Bathyarchaeota as groundwater autotrophs. Overall, the results suggest that the majority of Archaea on rocks are fixing CO2, while archaeal autotrophy seems to be limited in the groundwater. PMID:28694737

Lithologic mapping of the Mordor, NT, Australia ultramafic complex by using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)

USGS Publications Warehouse

Rowan, L.C.; Mars, J.C.; Simpson, C.J.

2005-01-01

Spectral measurements made in the Mordor Pound, NT, Australia study area using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), in the laboratory and in situ show dominantly Al-OH and ferric-iron VNIR-SWIR absorption features in felsic rock spectra and ferrous-iron and Fe,Mg-OH features in the mafic-ultramafic rock spectra. ASTER ratio images, matched-filter, and spectral-angle mapper processing (SAM) were evaluated for mapping the lithologies. Matched-filter processing in which VNIR + SWIR image spectra were used for reference resulted in 4 felsic classes and 4 mafic-ultramafic classes based on Al-OH or Fe,Mg-OH absorption features and, in some, subtle reflectance differences related to differential weathering and vegetation. These results were similar to those obtained by match-filter analysis of HyMap data from a previous study, but the units were more clearly demarcated in the HyMap image. ASTER TIR spectral emittance data and laboratory emissivity measurements document a wide wavelength range of Si-O spectral features, which reflect the lithological diversity of the Mordor ultramafic complex and adjacent rocks. SAM processing of the spectral emittance data distinguished 2 classes representing the mafic-ultramafic rocks and 4 classes comprising the quartzose to intermediate composition rocks. Utilization of the complementary attributes of the spectral reflectance and spectral emittance data resulted in discrimination of 4 mafic-ultramafic categories; 3 categories of alluvial-colluvial deposits; and a significantly more completely mapped quartzite unit than could be accomplished by using either data set alone. ?? 2005 Elsevier Inc. All rights reserved.

Modeling groundwater flow and quality

USGS Publications Warehouse

Konikow, Leonard F.; Glynn, Pierre D.; Selinus, Olle

2013-01-01

In most areas, rocks in the subsurface are saturated with water at relatively shallow depths. The top of the saturated zone—the water table—typically occurs anywhere from just below land surface to hundreds of feet below the land surface. Groundwater generally fills all pore spaces below the water table and is part of a continuous dynamic flow system, in which the fluid is moving at velocities ranging from feet per millennia to feet per day (Fig. 33.1). While the water is in close contact with the surfaces of various minerals in the rock material, geochemical interactions between the water and the rock can affect the chemical quality of the water, including pH, dissolved solids composition, and trace-elements content. Thus, flowing groundwater is a major mechanism for the transport of chemicals from buried rocks to the accessible environment, as well as a major pathway from rocks to human exposure and consumption. Because the mineral composition of rocks is highly variable, as is the solubility of various minerals, the human-health effects of groundwater consumption will be highly variable.

Earth Observations taken by the Expedition 23 Crew

NASA Image and Video Library

2010-04-30

ISS023-E-029806 (30 April 2010) --- Kata Tjuta, Australia is featured in this image photographed by an Expedition 23 crew member on the International Space Station. Located in the Northern Territory of Australia, Uluru – Kata Tjuta National Park hosts some of the world’s most spectacular examples of inselbergs, or isolated mountains. The most famous of these inselbergs is Uluru (also known as Ayers Rock). An equally massive inselberg located approximately 30 kilometers to the northwest is known as Kata Tjuta– like Uluru, this is a sacred site to the native Anangu or Aboriginal people. Explorers named the highest peak Mount Olga, with the entire grouping of rocks informally known as “the Olgas”. Mount Olga has a peak elevation of 1,069 meters above sea level, making it 206 meters higher than Uluru. Kata Tjuta is comprised of gently dipping Mount Currie Conglomerate, a sedimentary rock that includes abundant rounded fragments of other rock types (here, primarily granite with less abundant basalt and rhyolite) in a coarse sandy matrix. Geologists interpret the Mount Currie Conglomerate as a remnant of a large fan of material rapidly eroded from mountains uplifted approximately 550 million years ago. Subsequent burial under younger sediments consolidated the eroded materials to form the conglomerate exposed at the surface today. In this photograph, afternoon sunlight highlights the rounded summits of Kata Tjuta against the surrounding sandy plains. Sand dunes are visible at upper right; while in other areas (image top and image left) sediments washed from the rocks have been anchored by a variety of grasses and bushes adapted to the arid climate. Green vegetation in the ephemeral stream channels that drain Kata Tjuta (bottom center) provides colorful contrast with the red rocks and surrounding soils. Large gaps in the rocks (highlighted by shadows) are thought to be fractures that have been enlarged due to erosion.

3-D study of texture and elastic anisotropy on rocks from NW Italy Ivrea zone

NASA Astrophysics Data System (ADS)

Pros, Z.; Lokajicek, T.; Prikryl, R.; Klima, K.; Nikitin, A. N.; Ivankina, T. I.; Martinkova, M.

2003-04-01

The direct measurement of physical properties of lower crustal and upper mantle rocks, which can be found on the Earth's surface, could be used for the improving of our knowledge of deep rocks. These results could be used mainly for the correction of geological and geophysical models based on the indirect data. Elastic properties of rocks are one of the most important parameters studied and could be applied in many fields of Earth sciences. In this study several quite different methods were applied to determine elastic properties. P-wave ultrasonic sounding of mafic and ultrabasic rock samples in 132 independent directions at several levels of confining pressure enable to determine elastic anisotropy of P-wave velocity. The samples were collected in nearby of Balmuccia ultra basic massif (Ivrea zone, southern Alps, NW Italy). This method revealed large directional variance of maximum P-wave velocity and different symmetric (orthorhombic vs. transversal isotropic) of elastic waves 3-D distribution, that has not been found on these rocks before. Identical samples were studied by means of neutron diffraction. Neutron diffraction provide data on CPO orientation in identical spherical samples, on which was measured P-wave velocity. Laboratory 3-D measurement of P-wave velocity thus present powerful method for detection of magmatic fabric features not visible by naked eye. One dunite sample exhibits P-wave velocity approaching to that of olivine crystal 9.8 km/s due to the strong CPO of olivine in this sample. Such observation was not done before on the natural olivine-rich rocks. It follows from the comparison of measured and calculated P-wave velocities, that these values are more reliable than data obtained from measurement in few directions only. This project was supported by Grant Agency of the Czech Republic No.: 205/01/1430.

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

NASA Astrophysics Data System (ADS)

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

2016-12-01

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

Geotechnical applications of remote sensing and remote data transmission; Proceedings of the Symposium, Cocoa Beach, FL, Jan. 31-Feb. 1, 1986

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

Johnson, A.I.; Pettersson, C.B.

1988-01-01

Papers and discussions concerning the geotechnical applications of remote sensing and remote data transmission, sources of remotely sensed data, and glossaries of remote sensing and remote data transmission terms, acronyms, and abbreviations are presented. Aspects of remote sensing use covered include the significance of lineaments and their effects on ground-water systems, waste-site use and geotechnical characterization, the estimation of reservoir submerging losses using CIR aerial photographs, and satellite-based investigation of the significance of surficial deposits for surface mining operations. Other topics presented include the location of potential ground subsidence and collapse features in soluble carbonate rock, optical Fourier analysis ofmore » surface features of interest in geotechnical engineering, geotechnical applications of U.S. Government remote sensing programs, updating the data base for a Geographic Information System, the joint NASA/Geosat Test Case Project, the selection of remote data telemetry methods for geotechnical applications, the standardization of remote sensing data collection and transmission, and a comparison of airborne Goodyear electronic mapping system/SAR with satelliteborne Seasat/SAR radar imagery.« less

The role of post-failure brittleness of soft rocks in the assessment of stability of intact masses: FDEM technique applications to ideal problems

NASA Astrophysics Data System (ADS)

Lollino, Piernicola; Andriani, Gioacchino Francesco; Fazio, Nunzio Luciano; Perrotti, Michele

2016-04-01

Strain-softening under low confinement stress, i.e. the drop of strength that occurs in the post-failure stage, represents a key factor of the stress-strain behavior of rocks. However, this feature of the rock behavior is generally underestimated or even neglected in the assessment of boundary value problems of intact soft rock masses. This is typically the case when the stability of intact rock masses is treated by means of limit equilibrium or finite element analyses, for which rigid-plastic or elastic perfectly-plastic constitutive models, generally implementing peak strength conditions of the rock, are respectively used. In fact, the aforementioned numerical techniques are characterized by intrinsic limitations that do not allow to account for material brittleness, either for the method assumptions or due to numerical stability problems, as for the case of the finite element method, unless sophisticated regularization techniques are implemented. However, for those problems that concern the stability of intact soft rock masses at low stress levels, as for example the stability of shallow underground caves or that of rock slopes, the brittle stress-strain response of rock in the post-failure stage cannot be disregarded due to the risk of overestimation of the stability factor. This work is aimed at highlighting the role of post-peak brittleness of soft rocks in the analysis of specific ideal problems by means of the use of a hybrid finite-discrete element technique (FDEM) that allows for the simulation of the rock stress-strain brittle behavior in a proper way. In particular, the stability of two ideal cases, represented by a shallow underground rectangular cave and a vertical cliff, has been analyzed by implementing a post-peak brittle behavior of the rock and the comparison with a non-brittle response of the rock mass is also explored. To this purpose, the mechanical behavior of a soft calcarenite belonging to the Calcarenite di Gravina formation, extensively outcropping in Puglia (Southern Italy), and the corresponding features of the post-peak behavior as measured in the laboratory, have been used as a reference in this work, as well as the typical geometrical features of underground cavities and rock cliffs, as observed in Southern Italy, have been adopted for the simulations. The numerical results indicate the strong impact for the assessment of stability when rock post-peak brittleness is accounted for, if compared with perfectly plastic assumptions, and the need for adopting numerical techniques, as the FDEM approach, to take properly into account this important aspect of the rock behavior is highlighted.

Nearshore morphology and late Quaternary geologic framework of the northern Monterey Bay Marine Sanctuary, California

USGS Publications Warehouse

Anima, R.J.; Eittreim, S.L.; Edwards, B.D.; Stevenson, A.J.

2002-01-01

A combination of side-scanning sonar and high-resolution seismic reflection data image seafloor bedrock exposures and erosional features across the nearshore shelf. Sediment-filled troughs incise the inner shelf rock exposures and tie directly to modern coastal streams. The resulting bedrock geometry can be related to its resistance to erosion. Comparison of the depth of the transgressive erosional surface to recently developed sea level curves suggests a period of slow sea level rise during the early stages of post-interglacial marine transgression. The slow rise of sea level suggests an erosional episode that limited the preservation of buried paleo-channels beyond 70 m water depth. Seafloor features suggest that localized faulting in the area may have influenced the morphology of bedrock exposures and the coastline. ?? 2002 Elsevier Science B.V. All rights reserved.

Comparison of deformation mechanics for two different carbonates: oolitic limestone and laminites

NASA Astrophysics Data System (ADS)

Zihms, Stephanie; Lewis, Helen; Couples, Gary; Hall, Stephen; Somerville, Jim

2016-04-01

Carbonate rocks form under a range of conditions which leads to a diverse rock group. Even though carbonates are overall mineralogically simple, the solid-space distribution ranges from simple compositions such as oolitic limestones to highly complex networks of pores and solids as seen in coquinas. Their fundamental mechanical behaviour has been identified to be like clastic rocks (Vajdova 2004, Brantut, Heap et al. 2014). However it is very likely that this observation is not true for more complex carbonates. Triaxial tests were performed on cylindrical samples of two different carbonates; a) oolitic limestone (Bicqueley quarry, France) and b) laminite (Ariripe basin, Brazil). The samples were deformed under confining pressures of 8, 12 and 20MPa, and 20, 30 and 40MPa, respectively. All tests were stopped as soon as peak load was observed to preserve as many deformation characteristics as possible. Photographs of the samples were taken before and after deformation to allow surface analysis of deformation features. Additionally, samples were analysed post-deformation with X-ray tomography (XRT) (using the Zeiss XRadia XRM 520 at the 4D Imaging Lab at Lund University). The 3D tomography images represent the post-deformation samples' density distribution, allowing detailed, non-destructive, 3D analysis of the deformation features that developed in the triaxial testing, including the complex geometries and interactions of fractures, deformation bands and sedimentary layering. They also provide an insight into the complexity of deformation features produced due to the carbonate response. Initial results show that the oolitic limestone forms single shear bands almost the length of the sample, exhibiting similar characteristics to sandstones deformed under similar conditions. These features are observed for all three applied loads. The laminate sample deformed at the lowest confining pressure exhibits compactive features. However, the laminite samples deformed at the two higher confining pressures both show highly complex fracture networks comprising open fractures and fracture propagation. This suggests that the laminate changes from compactive to dilational responses over the selected confining conditions. The XRT analysis indicates that a more complex fracture distribution could be linked to rock component properties e.g. grain size and composition. For the laminite these are variable with the layers. This is in agreement with field observations of laminite microfabrics (Calvo, Rodriguez-Pascua et al. 1998). Additionally, the typical grain size of the laminate (μm) is much smaller than the oolitic limestone (mm), which suggests that fracture network complexity can also be linked to bulk system complexity i.e. pore & grain network. These deformation experiments show that, as previously observed, oolitic limestones seem to behave similarly to sandstones. However this observation is not true for laminites and it is very likely that more complex carbonates will develop even more complicated deformation behaviour. It is therefore necessary to systematically test different carbonate rocks to understand the impact of geometry and composition, as well as the interplay with the pore network. Brantut, N., et al. (2014). Journal of Geophysical Research: Solid Earth 119(7): 5444-5463. Calvo, J. P., et al. (1998). Sedimentology 45: 279-292. Vajdova, V. (2004). Journal of Geophysical Research 109(B5).

Thermal contraints on high-pressure granulite metamorphism of supracrustal rocks

NASA Technical Reports Server (NTRS)

Ashwal, L. D.; Morgan, P.; Leslie, W. W.

1983-01-01

The circumstances leading to the formation and exposure at the Earth's surface of supracrustal granulites are examined. These are defined as sediments, volcanics, and other rock units which originally formed at the surface of the Earth, were metamorphosed to high-pressure granulite facies (T = 700-900 C, P = 5-10 kbar), and reexposed at the Earth's surface, in many cases underlain by normal thicknesses of continental crust (30-40 km). Five possible heating mechanisms to account for granulite metamorphism of supracrustal rocks are discussed: magnetic heating, thermal relaxation of perturbed temperature profiles following underthrusting of the continental crust, thermal relaxation after underthrusting of thin slivers of supracrustal rocks below continental crust of normal thickness, major preheating of the upper plate, and shear heating caused by frictional stress along the thrust plane.

Multispectral Imaging of Mars from the Mars Science Laboratory Mastcam Instruments: Spectral Properties and Mineralogic Implications Along the Gale Crater Traverse

NASA Astrophysics Data System (ADS)

Bell, James F.; Wellington, Danika; Hardgrove, Craig; Godber, Austin; Rice, Melissa S.; Johnson, Jeffrey R.; Fraeman, Abigail

2016-10-01

The Mars Science Laboratory (MSL) Curiosity rover Mastcam is a pair of multispectral CCD cameras that have been imaging the surface and atmosphere in three broadband visible RGB color channels as well as nine additional narrowband color channels between 400 and 1000 nm since the rover's landing in August 2012. As of Curiosity sol 1159 (the most recent PDS data release as of this writing), approximately 140 multispectral imaging targets have been imaged using all twelve unique bandpasses. Near-simultaneous imaging of an onboard calibration target allows rapid relative reflectance calibration of these data to radiance factor and estimated Lambert albedo, for direct comparison to lab reflectance spectra of rocks, minerals, and mixtures. Surface targets among this data set include a variety of outcrop and float rocks (some containing light-toned veins), unconsolidated pebbles and clasts, and loose sand and soil. Some of these targets have been brushed, scuffed, or otherwise disturbed by the rover in order to reveal the (less dusty) interiors of these materials, and those targets and each of Curiosity's drill holes and tailings piles have been specifically targeted for multispectral imaging.Analysis of the relative reflectance spectra of these materials, sometimes in concert with additional compositional and/or mineralogic information from Curiosity's ChemCam LIBS and passive-mode spectral data and CheMin XRD data, reveals the presence of relatively broad solid state crystal field and charge transfer absorption features characteristic of a variety of common iron-bearing phases, including hematite (both nanophase and crystalline), ferric sulfate, olivine, and pyroxene. In addition, Mastcam is sensitive to a weak hydration feature in the 900-1000 nm region that can provide insight on the hydration state of some of these phases, especially sulfates. Here we summarize the Mastcam multispectral data set and the major potential phase identifications made using that data set during the traverse so far in Gale crater, and describe the ways that Mastcam multispectral observations will continue to inform the ongoing ascent and exploration of Mt. Sharp, Gale crater's layered central mound of sedimentary rocks.

A Martian analog in Kansas: Comparing Martian strata with Permian acid saline lake deposits

NASA Astrophysics Data System (ADS)

Benison, Kathleen C.

2006-05-01

An important result of the Mars Exploration Rover's (MER) mission has been the images of sedimentary structures and diagenetic features in the Burns Formation at Meridiani Planum. Bedding, cross-bedding, ripple marks, mud cracks, displacive evaporite crystal molds, and hematite concretions are contained in these Martian strata. Together, these features are evidence of past saline groundwater and ephemeral shallow surface waters on Mars. Geochemical analyses of these Martian outcrops have established the presence of sulfates, iron oxides, and jarosite, which strongly suggests that these waters were also acidic. The same assemblage of sedimentary structures and diagenetic features is found in the salt-bearing terrestrial red sandstones and shales of the middle Permian (ca. 270 Ma) Nippewalla Group of Kansas, which were deposited in and around acid saline ephemeral lakes. These striking sedimentological and mineralogical similarities make these Permian red beds and evaporites the best-known terrestrial analog for the Martian sedimentary rocks at Meridiani Planum.

Method based on artificial excitation of characteristic radiation by an electron beam for remote X-ray spectral elemental analysis of surface rocks on atmosphereless celestial bodies

NASA Astrophysics Data System (ADS)

Kolesnikov, E. K.

2016-11-01

This article, like our previous one [1], is devoted to advanced space technology concepts. It evaluates the potential for developing active systems to conduct a remote elemental analysis of surface rocks on an atmosphereless celestial body. The analysis is based on the spectrometry of characteristic X-rays (CXR) artificially excited in the surface soil layer. It has been proposed to use an electron beam injected from aboard a spacecraft orbiting the celestial body (or moving in a flyby trajectory) to excite the CXR elements contained in surface rocks. The focus is on specifying technical requirements to the parameters of payloads for a global mapping of the composition of lunar rocks from aboard of a low-orbiting lunar satellite. This article uses the results obtained in [2], our first study that shows the potential to develop an active system for a remote elemental analysis of lunar surface rocks using the above method. Although there has been interest in our research on the part of leading national academic institutions and space technology developers in the Soviet Union, the studies were discontinued because of the termination of the Soviet lunar program and the completion of the American Apollo program.

Multiscale Feature Analysis of Salivary Gland Branching Morphogenesis

PubMed Central

Baydil, Banu; Daley, William P.; Larsen, Melinda; Yener, Bülent

2012-01-01

Pattern formation in developing tissues involves dynamic spatio-temporal changes in cellular organization and subsequent evolution of functional adult structures. Branching morphogenesis is a developmental mechanism by which patterns are generated in many developing organs, which is controlled by underlying molecular pathways. Understanding the relationship between molecular signaling, cellular behavior and resulting morphological change requires quantification and categorization of the cellular behavior. In this study, tissue-level and cellular changes in developing salivary gland in response to disruption of ROCK-mediated signaling by are modeled by building cell-graphs to compute mathematical features capturing structural properties at multiple scales. These features were used to generate multiscale cell-graph signatures of untreated and ROCK signaling disrupted salivary gland organ explants. From confocal images of mouse submandibular salivary gland organ explants in which epithelial and mesenchymal nuclei were marked, a multiscale feature set capturing global structural properties, local structural properties, spectral, and morphological properties of the tissues was derived. Six feature selection algorithms and multiway modeling of the data was performed to identify distinct subsets of cell graph features that can uniquely classify and differentiate between different cell populations. Multiscale cell-graph analysis was most effective in classification of the tissue state. Cellular and tissue organization, as defined by a multiscale subset of cell-graph features, are both quantitatively distinct in epithelial and mesenchymal cell types both in the presence and absence of ROCK inhibitors. Whereas tensor analysis demonstrate that epithelial tissue was affected the most by inhibition of ROCK signaling, significant multiscale changes in mesenchymal tissue organization were identified with this analysis that were not identified in previous biological studies. We here show how to define and calculate a multiscale feature set as an effective computational approach to identify and quantify changes at multiple biological scales and to distinguish between different states in developing tissues. PMID:22403724

Demonstrations of Gravity-Independent Mobility and Drilling on Natural Rock using Microspines

NASA Technical Reports Server (NTRS)

Parness, Aaron; Frost, Matthew; King, Jonathan P.; Thatte, Nitish

2012-01-01

The video presents microspine-based anchors be ing developed for gripping rocks on the surfaces of comets and asteroids, or for use on cliff faces and lava tubes on Mars. Two types of anchor prototypes are shown on supporting forces in all directions away from the rock; >160 N tangent, >150 N at 45?, and >180 N normal to the surface of the rock. A compliant robotic ankle with two active degrees of freedom interfaces these anchors to the Lemur IIB robot for future climbing trials. Finally, a rotary percussive drill is shown coring into rock regardless of gravitational orientation. As a harder- than-zero-g proof of concept, inverted drilling was performed creating 20mm diameter boreholes 83 mm deep in vesicular basalt samples while retaining 12 mm diameter rock cores in 3-6 pieces.

Martian and Terrestrial Rock Abrasion from Wind Tunnel and Field Studies

NASA Technical Reports Server (NTRS)

Bridges, N. T.; Greeley, R.; Eddlemon, E.; Laity, J. E.; Meyer, C.; Phoreman, J.; White, B. R.

2003-01-01

Earth and Mars exhibit ventifacts, rocks that have been abraded by saltating sand. Previous theoretical and laboratory studies have determined abrasion susceptibilities of rocks as a function of sand type and impact angle and rock material strengths. For the last two years we have been engaged in wind tunnel and field studies to better understand the fundamental factors which control and influence rock abrasion and ventifact formation on Earth and Mars. In particular, we are examining: 1) What types of rocks (composition, texture, and shape) preferentially erode and what are the relative rates of one type vs. another? 2) What are the controlling factors of the aeolian sand cloud (flux, particle speed, surface roughness, etc) which favor rock abrasion?, 3) How do specific ventifact characteristics tie into their mode of formation and rock properties? We find several important factors: 1) Initial rock shape controls the rate of abrasion, with steeper faces abrading faster than shallower ones. The relationship is partly dependent on angle-dependent flux (proportional to sin[theta]) but exhibits additional non-linear effects from momentum transfer efficiency and rebound effects that vary with incidence angle. 2) Irregular targets with pits or grooves abrade at greater rates than targets with smooth surfaces, with indentations generally enlarging with time. Surfaces become rougher with time. 3) Targets also abrade via slope retreat, which is roughly dependent on the slope of the front face. The formation of basal sills is common, as observed on terrestrial and Martian ventifacts.

First characterisation of the "Rumi-Pana" rock avalanche deposits (Famatina Range, La Rioja, Argentina)

NASA Astrophysics Data System (ADS)

Santiago Pullarello, José; Derron, Marc-Henri; Penna, Ivanna; Leiva, Alicia; Jaboyadoff, Michel

2017-04-01

Active mountain fronts are subject to large scale slope collapses which have the capacity to run long distances on piedmont areas. Along time, fluvial activity and other gravitatory processes can intensively erode and mask primary features related to the collapses. Therefore, to reconstruct the history of their occurrence, further analyses are needed, e.g. sedimentologic analyses. This work focuses on the occurrence of large rock avalanches in the Vinchina region, La Rioja (28°43'27.81'' S / 68°00'25.42'' W) on the western side of the Famatina range(Argentina). Here, photointerpretation of high resolution satellite images (Google Earth) allowed us to identify two rock avalanches, main scarps developed at 2575 and 2750 m a.s.l. . There are no absolute ages for these deposits, however, comparing their preservation degree with those dated further north (in similar climatic and landscape dynamics contexts [i]), we can suggest these rock avalanches took place during the Pleistocene. We carried out a fieldwork survey in this remote area, including classical landslide mapping, structural analysis, deposits characterization and sampling. The deposits reach the valley bottom (at around 1700 m a.s.l.) with runouts about 5 and 5.3 km long. In one of the cases, the morphology of the deposit is well preserved, allowing to reconstruct accurately its extension. However, in the second case, the deposits are strongly eroded by courses draining the mountain front, therefore further analyses should be done to reconstruct its extension. In addition to morphologic interpretations, a multiscale grain-size analysis was done to differentiate rock avalanches from other hillslope deposits: (1) 3D surface models of surface plots (5x5m) have been built by SfM photogrammetry; 2) classical sieving and 3) laser grain-size analysis of deposits. Samples were collected on different parts of the slope, but also along cross sections through the avalanche deposit. This deposits characterization will be combined with results from mapping and image analysis in order to provide a first description of the sequence and extension of events related to the evolution of this mountain front. [i] Hermanns et Strecker, Structural and lithological controls on large Quaternary rock avalanches (sturzstroms) in arid northwestern Argentina, Geological Society of America Bulletin 1999.

43 CFR 15.2 - Removal or destruction of natural features and marine life.

Code of Federal Regulations, 2012 CFR

2012-10-01

... marine invertebrates, seaweeds, grasses, or any soil, rock, artifacts, stones or other materials. No... this Preserve. No rope, wire or other contrivance shall be attached to any coral, rock or other...

Thermal and hydrologic attributes of rock glaciers and periglacial talus landforms: Sierra Nevada, California, USA

Treesearch

Constance I. Millar; Robert D. Westfall; Diane L. Delany

2013-01-01

To explore thermal regimes and hydrologic capacity of rock glaciers and related periglacial talus landforms, mini-thermochrons were deployed in and around potentially ice-embedded features of the Sierra Nevada. Results from pilot studies at 13 rock glaciers and 7 taluses indicate that outlet springs from these landforms generally do not desiccate but persist year...

Altered rock spectra in the visible and near infrared. [western Nevada

NASA Technical Reports Server (NTRS)

Hunt, G. R.; Ashley, R. P. (Principal Investigator)

1979-01-01

The author has identified the following significant results. Visible and near-infrared (0.35 to 2.5 micron m) bidirectional reflection spectra recorded for a suite of well-characterized hydrothermally altered rock samples typically display well defined bands caused by both electronic and vibrational processes in the individual mineral constituents. Electronic transitions in the iron-bearing constituent minerals produce diagnostic minima near 0.43, 0.65, 0.85, and 0.93 micron m. Vibrational transitions in clay and water-bearing mineral constituents produce characteristic single or multiple features over limited spectral ranges near 1.4, 1.75, 1.9, 2.2, and 2.35 micron m. The most abundant feature-producing minerals present in these rocks are hematite, goethite, and alunite. Others frequently present are jarosite, kaolinite, potassium micas, pyrophyllite, montmorillonite, diaspore, and gypsum. The spectral region near 2.2 micron m is particularly important for detecting altered rocks by remote sensing.

Elemental geochemistry of sedimentary rocks at Yellowknife Bay, Gale crater, Mars.

PubMed

McLennan, S M; Anderson, R B; Bell, J F; Bridges, J C; Calef, F; Campbell, J L; Clark, B C; Clegg, S; Conrad, P; Cousin, A; Des Marais, D J; Dromart, G; Dyar, M D; Edgar, L A; Ehlmann, B L; Fabre, C; Forni, O; Gasnault, O; Gellert, R; Gordon, S; Grant, J A; Grotzinger, J P; Gupta, S; Herkenhoff, K E; Hurowitz, J A; King, P L; Le Mouélic, S; Leshin, L A; Léveillé, R; Lewis, K W; Mangold, N; Maurice, S; Ming, D W; Morris, R V; Nachon, M; Newsom, H E; Ollila, A M; Perrett, G M; Rice, M S; Schmidt, M E; Schwenzer, S P; Stack, K; Stolper, E M; Sumner, D Y; Treiman, A H; VanBommel, S; Vaniman, D T; Vasavada, A; Wiens, R C; Yingst, R A

2014-01-24

Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine-rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.

PRo3D®: A Tool for High Resolution Rendering and Geological Analysis of Martian Rover-Derived Digital Outcrop Models.

NASA Astrophysics Data System (ADS)

Gupta, S.; Barnes, R.; Ortner, T.; Huber, B.; Paar, G.; Muller, J. P.; Giordano, M.; Willner, K.; Traxler, C.; Juhart, K.; Fritz, L.; Hesina, G.; Tasdelen, E.

2015-12-01

NASA's Mars Exploration Rovers (MER) and Mars Science Laboratory Curiosity Rover (MSL) are proxies for field geologists on Mars, taking high resolution imagery of rock formations and landscapes which is analysed in detail on Earth. Panoramic digital cameras (PanCam on MER and MastCam on MSL) are used for characterising the geology of rock outcrops along rover traverses. A key focus is on sedimentary rocks that have the potential to contain evidence for ancient life on Mars. Clues to determine ancient sedimentary environments are preserved in layer geometries, sedimentary structures and grain size distribution. The panoramic camera systems take stereo images which are co-registered to create 3D point clouds of rock outcrops to be quantitatively analysed much like geologists would do on Earth. The EU FP7 PRoViDE project is compiling all Mars rover vision data into a database accessible through a web-GIS (PRoGIS) and 3D viewer (PRo3D). Stereo-imagery selected in PRoGIS can be rendered in PRo3D, enabling the user to zoom, rotate and translate the 3D outcrop model. Interpretations can be digitised directly onto the 3D surface, and simple measurements can be taken of the dimensions of the outcrop and sedimentary features. Dip and strike is calculated within PRo3D from mapped bedding contacts and fracture traces. Results from multiple outcrops can be integrated in PRoGIS to gain a detailed understanding of the geological features within an area. These tools have been tested on three case studies; Victoria Crater, Yellowknife Bay and Shaler. Victoria Crater, in the Meridiani Planum region of Mars, was visited by the MER-B Opportunity Rover. Erosional widening of the crater produced <15 m high outcrops which expose ancient Martian eolian bedforms. Yellowknife Bay and Shaler were visited in the early stages of the MSL mission, and provide excellent opportunities to characterise Martian fluvio-lacustrine sedimentary features. Development of these tools is crucial to exploitation of vision data from future missions, such as the 2018 ExoMars Rover and the NASA 2020 mission. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 312377 PRoViDE.

Rho-associated kinase (ROCK) inhibition reverses low cell activity on hydrophobic surfaces.

PubMed

Tian, Yu Shun; Kim, Hyun Jung; Kim, Hyun-Man

2009-08-28

Hydrophobic polymers do not offer an adequate scaffold surface for cells to attach, migrate, proliferate, and differentiate. Thus, hydrophobic scaffolds for tissue engineering have traditionally been physicochemically modified to enhance cellular activity. However, modifying the surface by chemical or physical treatment requires supplementary engineering procedures. In the present study, regulation of a cell signal transduction pathway reversed the low cellular activity on a hydrophobic surface without surface modification. Inhibition of Rho-associated kinase (ROCK) by Y-27632 markedly enhanced adhesion, migration, and proliferation of osteoblastic cells cultured on a hydrophobic polystyrene surface. ROCK inhibition regulated cell-cycle-related molecules on the hydrophobic surface. This inhibition also decreased expression of the inhibitors of cyclin-dependent kinases such as p21(cip1) and p27(kip1) and increased expression of cyclin A and D. These results indicate that defective cellular activity on the hydrophobic surface can be reversed by the control of a cell signal transduction pathway without physicochemical surface modification.

Development of partial rock veneers by root throw in a subalpine setting

USGS Publications Warehouse

Osterkamp, W.R.; Toy, T.J.; Lenart, M.T.

2006-01-01

Rock veneers stabilize hillslope surfaces, occur especially in areas of immature soil, and form through a variety of process sets that includes root throw. Near Westcliffe, Colorado, USA, data were collected from a 20 ?? 500 m transect on the east slope of the Sangre de Cristo Mountains. Ages of pit/mound complexes with rock fragments exposed at the surface by root throw ranged from recent (freshly toppled tree) to unknown (complete tree decay). Calculations based on dimensions of the pit/mound complexes, estimated time of free topppling, sizes of exposed rock fragments, and percentage rock covers at pit/mound complexes, as well as within the transect area, indicate that recent rates of root throw have resulted in only partial rock veneering since late Pleistocene deglaciation. Weathering of rock fragments prevent development of an extensive rock veneer and causes a balance, achieved within an estimated 700 years, between the rates of rock-fragment exposure by root throw and clast disintegration by chemical reduction. The estimated rate of rock-fragment reduction accounts for part of the fluvial sediment yields observed for forested subalpine areas of western North America. Copyright ?? 2005 John Wiley & Sons, Ltd.

The role of volatiles and lithology in the impact cratering process

NASA Technical Reports Server (NTRS)

Kieffer, S. W.; Simonds, C. H.

1980-01-01

A survey of published descriptions of 32 of the largest, least eroded terrestrial impact structures shows that the amount of melt at craters in crystalline rocks is approximately two orders of magnitude greater than that at craters in sedimentary rocks. A model is proposed for the impact process, and it is examined whether the difference in melt abundance is due to differences in the amount of melt generated in various target materials or due to differences in the fate of the melt during late stages of the impact. The model accounts semiquantitatively for the effects of porosity and water and volatile content on the cratering process. Important features of the model are noted. Even if the recondensation of released volatiles is very efficient, the cumulative effect of repeated impacts on accreting planets would be to continually transfer volatiles toward the outer surface. By this process, volatiles might be enriched toward the outer layer of a growing planet.

Tilted middle Tertiary ash-flow calderas and subjacent granitic plutons, southern Stillwater Range, Nevada: cross sections of an Oligocene igneous center

USGS Publications Warehouse

John, D.A.

1995-01-01

Steeply tilted late Oligocene caldera systems in the Stillwater caldera complex record a number of unusual features including extreme thickness of caldera-related deposits, lack of evidence for structural doming of the calderas and preservation of vertical compositional zoning in the plutonic rocks. The Stillwater caldera complex comprises three partly overlapping ash-flow calderas and subjacent plutonic rocks that were steeply tilted during early Miocene extension. The Job Canyon caldera, the oldest (ca. 29-28 Ma) caldera, consists of two structural blocks. The 25 to 23 Ma Poco Canyon and Elevenmile Canyon calderas and underlying Freeman Creek pluton overlap in time and space with each other. Caldera collapse occurred mostly along subvertical ring-fracture faults that penetrated to depths of >5 km and were repeatedly active during eruption of ash-flow tuffs. The calderas collapsed as large piston-like blocks, and there is no evidence for chaotic collapse. Preserved parts of caldera floors are relatively flat surfaces several kilometers across. -from Author