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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Relation of lineaments to sulfide deposits: Bald Eagle Mountain, Centre County, Pennsylvania

The author has identified the following significant results. Discrete areas of finely-fractured and brecciated sandstone float are present along the crest of Bald Mountain and are commonly sites of sulfide mineralization, as evidenced by the presence of barite and limonite gossans. The frequency distributions of the brecciated float as the negative binomial distribution supports the interpretation of a separate population of intensely fractured material. Such zones of concentrated breccia float have an average width of one kilometer with a range from 0.4 to 1.6 kilometers and were observed in a quarry face to have subvertical dips. Direct spatial correlation of the Landsat-derived lineaments to the fractured areas on the ridge is low; however, the mineralized and fracture zones are commonly assymetrical to the lineament positions. Such a systematic dislocation might result from an inherent bias in the float population or could be the product of the relative erosional resistance of the silicified material in the mineralized areas in relation to the erosionally weak material at the stream gaps.

Mcmurtry, G. J.↗
NASA NTRS1975

SLAR reconnaissance, Mimika-Eilanden Basin, Southern Trough of Irian Jaya

The SLAR was obtained in early April 1973 by means of an AN/APQ-97 K-band brute-force system. The flight strips are all north-look, with ground-range display, and 60% overlap. The interpretation was compiled on a 1/100,000-scale mosaic, but the actual mapping of contacts, dips, lineaments, and the like, was done on 1/100,000-scale stereo-strips. Initial regional mapping was intended as an aid in determining that part of the Southern Trough most likely to be underlain by relatively unmetamorphosed paralic Kembelangan sandstones ideally interdigitated with marine source and cape shales. SLAR reconnaissance mapping met a subsequent need to rapidly and inexpensively narrow the search to that part of the "fairway' coincident with a favorable structure. The SLAR mosaic clearly displays the Irian mountains, strongly and gently folded foothills belts, and the southern front of the fold belt south of which is a large complex of alluvial fans.

Wing, R. S.↗
NASA NTRS1975

The anatomy of an anomaly

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.

Short, N. M.↗
NASA NTRS1976

Geological applications of Nimbus radiation data in Middle East

Plateaus of Eocene limestone and exposed limestone escarpments, in Egypt and Saudi Arabia respectively, were indicated by cool brightness temperatures T sub B (less than 240 to 265 K) by the Nimbus 5 electrically scanning microwave radiometer (ESMR) over a 2-year period. Nubian sandstone, desert eolian sand and igneous metamorphic rocks were differentiated from these limestone areas by warm T sub B values (more than 265 to 300 K). Cool T sub B values in the form of a V were found over broad areas of the Nile Valley and in the western desert of central Egypt. Similar cool T sub B values were shown over limestone-dolomitic hills of the interior Homocline and the Hadramawt plateau of Saudi Arabia. Nimbus 5 and 6 ESMR T sub B values selectively identified intermediate dense rock types (limestone versus sandstone/granite) in the Lake Nasser region whose thermal inertia ranged from 0.035 to 0.06 cal cm to minus 2 C sec 1/2 to minus one half.

Allison, L. J.↗
NASA NTRS1976

Metal spherules in Wabar, Monturaqui, and Henbury impactites

The Fe, Ni, and Co contents of 450 spherules with diameters of 3 to 100 microns in impact glasses from three terrestrial meteorite craters are determined by electron microprobe analysis. The objects investigated include 250 spherules from Wabar (Saudi Arabia) impactite and 100 each from Monturaqui (Chile) and Henbury (Australia) impactites. The specimens and spherules are described, noting that the Wabar and Henbury craters were produced in sandstone while the Monturaqui crater was formed in siliceous igneous rocks and has an enigmatic sulfide abundance. It is found that the spherules are enriched in Ni and Co relative to the original meteorite Fe content and are enriched in Ni relative to Co for Ni contents greater than 50%. The results indicate that, on the average, Henbury spherules are more Ni-enriched than Monturaqui spherules, and Wabar spherules exhibit the least Ni-enrichment. It is suggested that the spherules could have formed without experiencing free flight and that instantaneous dissemination of meteoritic material at the meteorite-target contact was the major fractionation process.

Gibbons, R. V.↗
NASA NTRS1978

Discrimination of rock classes and alteration products in southwestern Saudi Arabia with computer-enhanced LANDSAT data

Digital LANDSAT MSS data for an area in the southwestern Arabian Shield were computer-enhanced to improve discrimination of rock classes, and recognition of gossans associated with massive sulphide deposits. The test area is underlain by metamorphic rocks that are locally intruded by granites; these are partly overlain by sandstones. The test area further includes the Wadi Wassat and Wadi Qatan massive sulphide deposits, which are commonly capped by gossans of ferric oxides, silica, and carbonates. Color patterns and boundaries on contrast-stretched ratio color composite imagery, and on complementary images constructed using principal component and canonical analyses transformations, correspond exceptionally well to 1:100,000 scale field maps. A qualitative visual comparison of information content showed that the ratio enhancement provided the best overall image for identification of rock type and alteration products.

Blodget, H. W.↗
NASA NTRS1979

Late diagenetic indicators of buried oil and gas. 2: Direct detection experiment at Cement and Garza fields, Oklahoma and Texas, using enhanced LANDSAT 1 and 2 images

The author has identified the following significant results. The Cement oil field, Oklahoma, was a test site for an experiment designed to evaluate LANDSAT's capability to detect an alteration zone in surface rocks caused by hydrocarbon microseepage. Loss of iron and impregnation of sandstone by carbonate cements and replacement of gypsum by calcite were the major alteration phenomena at Cement. The bedrock alterations were partially masked by unaltered overlying beds, thick soils, and dense natural and cultivated vegetation. Interpreters, biased by detailed ground truth, were able to map the alteration zone subjectively using a magnified, filtered, and sinusoidally stretched LANDSAT composite image; other interpreters, unbiased by ground truth data, could not duplicate that interpretation.

Donovan, T. J.↗
NASA NTRS1980

Studies on questions of design and construction of chain scraper conveyors

The basic behavior of mining crushed goods in chain scraper conveyors was examined using a special test stand. The characteristics resistance lines of the upper end-piece were determined for conveyor idle as a function of the determinative crushed good characteristics (granular structure, moisture content, type of goods) on the size of the conveyor load, on the conveyor construction and on the stopped time of the conveyor. Crushed goods with a narrow granular profile and sphere-like grains caused about 35% greater resistance than fine coal and raw coal with broad granular profile. For goods containing water more than 10% by weight, the solids friction retreated in favor of flow friction. The coefficient of resistance decreased considerably in the range of lower speeds and then increased with increasing conveyor speed. The conveyance of sandstone ore required about 280% greater specific drive than the conveyance of raw coal. Resistance coefficients for coal and raw coal showed no dependence on the design of the conveyor. Start-up of loaded conveyors after longer stop times was simulated and the specific break-loose force was determined.

Guder, H.↗
NASA NTRS1980

Soil moisture in relation to geologic structure and lithology, northern California

The author has identified the following significant results. Structural features in the Norther California Coast Ranges are clearly discernable on Nite-IR images and some of the structural linears may results in an extension of known faults within the region. The Late Mesozoic marine sedimentary rocks along the western margin of the Sacramento Valley are clearly defined on the Nite-IR images and in a gross way individual layers of sandstone can be differentiated from shale. Late Pleistocene alluvial fans are clearly differentiated from second generation Holocene fans on the basis of tonal characteristics. Although the tonal characteristics change with the seasons, the differentiation of the two sets of fans is still possible.

Rich, E. I.↗
NASA NTRS1980

Remote sensing data applied to the evaluation of soil erosion caused by land-use. Ribeirao Anhumas Basin Area: A case study

Formerly covered by a tropical forest, the study area was deforested in the early 40's for coffee plantation and cattle raising, which caused intense gully erosion problems. To develop a method to analyze the relationship between land use and soil erosion, visual interpretations of aerial photographs (scale 1:25.000), MSS-LANDSAT imagery (scale 1:250,000), as well as automatic interpretation of computer compatible tapes by IMAGE-100 system were carried out. From visual interpretation the following data were obtained: land use and cover tapes, slope classes, ravine frequency, and a texture sketch map. During field work, soil samples were collected for texture and X-ray analysis. The texture sketch map indicate that the areas with higher slope angles have a higher susceptibilty to the development of gullies. Also, the over carriage of pastureland, together with very friable lithologies (mainly sandstone) occuring in that area, seem to be the main factors influencing the catastrophic extension of ravines in the study site.

Dejesusparada, N.↗
NASA NTRS1981

Remote sensing and uranium exploration at Lisbon Valley, Utah

As part of the joint NASA-Geosat uranium test case program, aircraft-acquired multispectral scanner data are used to investigate the distribution of bleaching in Windgate sandstone exposed in Lisbon Valley anticline, Utah. It is noted that all of the large ore bodies contained in lower Chinle Triassic age or Cutler Permian age strata in this area lie beneath or closely adjacent to such bleached outcrops. The geographic coincidences reported here are seen as inviting renewed interest in speculation of a causal relation between occurrences of Mississippian-Pennsylvanian oil and gas in this area and of Triassic uranium accumulation and rock bleaching.

Conel, J. E.↗
NASA NTRS1983

Regional geothermal exploration in Egypt

A study is presented of the evaluation of the potential geothermal resources of Egypt using a thermal gradient/heat flow technique and a groundwater temperature/chemistry technique. Existing oil well bottom-hole temperature data, as well as subsurface temperature measurements in existing boreholes, were employed for the thermal gradient/heat flow investigation before special thermal gradient holes were drilled. The geographic range of the direct subsurface thermal measurements was extended by employing groundwater temperature and chemistry data. Results show the presence of a regional thermal high along the eastern margin of Egypt with a local thermal anomaly in this zone. It is suggested that the sandstones of the Nubian Formation may be a suitable reservoir for geothermal fluids. These findings indicate that temperatures of 150 C or higher may be found in this reservoir in the Gulf of Suez and Red Sea coastal zones where it lies at a depth of 4 km and deeper.

Morgan, P.↗
NASA NTRS1984

Fluvial erosion of impact craters: Earth and Mars

Geomorphic studies of impact structures in central Australia are being used to understand the complexities of fluvial dissection in the heavily cratered terrains of Mars. At Henbury, Northern Territory, approximately 12 small meteorite craters have interacted with a semiarid drainage system. The detailed mapping of the geologic and structural features at Henbury allowed this study to concentrate on degradational landforms. The breaching of crater rims by gullies was facilitated by the northward movement of sheetwash along an extensive pediment surface extending from the Bacon Range. South-facing crater rims have been preferentially breached because gullies on those sides were able to tap the largest amounts of runoff. At crater 6 a probable rim-gully system has captured the headward reaches of a pre-impact stream channel. The interactive history of impacts and drainage development is critical to understanding the relationships in the heavily cratered uplands of Mars. Whereas Henbury craters are younger than 4700 yrs. B.P., the Gosses Bluff structure formed about 130 million years ago. The bluff is essentially an etched central peak composed of resistant sandstone units. Fluvial erosion of this structure is also discussed.

Baker, V. R.↗
NASA NTRS1984

Radar backscatter modelling

The terrain analysis software package was restructured and documentation was added. A program was written to test Johnson Space Center's four band scatterometer data for spurious signals data. A catalog of terrain roughness statistics and calibrated four frequency multipolarization scatterometer data is being published to support the maintenance of Death Valley as a radar backscatter calibration test site for all future airborne and spacecraft missions. Test pits were dug through sand covered terrains in the Eastern Sahara to define the depth and character of subsurface interfaces responsible for either backscatter or specular response in SIR-A imagery. Blocky sandstone bedrock surfaces at about 1 m depth were responsible for the brightest SIR-A returns. Irregular very dense CaCO3 cemented sand interfaces were responsible for intermediate grey tones. Ancient river valleys had the weakest response. Reexamination of SEASAT l-band imagery of U.S. deserts continues.

Schaber, G. G.↗
NASA NTRS1984

The Antarctic cryptoendolithic ecosystem - Relevance to exobiology

Cryptoendolithic microorganisms in the Antarctic desert live inside porous sandstone rocks, protected by a thin rock crust. While the rock surface is abiotic, the microclimate inside the rock is comparatively mild. These organisms may have descended from early, pre-glaciation Antarctic life forms and thus may represent the last outpost of life in a gradually deteriorating environment. Assuming that life once arose on Mars, it is conceivable that, following the loss of water, the last of surviving organisms withdrew to similar insulated microenvironments. Because such microscopic pockets have little connection with the outside environment, their detection may be difficult. The chances that the Viking lander could sample cryptoendolithic microorganisms in the Antarctic desert would be infinitesimal.

Friedmann, E. I.↗
NASA NTRS1984

Utilization of LANDSAT orbital imagery in the soil survey processes at Rio Grande do Norte state

Pedologic photointerpretative criteria adapted to LANDSAT orbital imagery were used: drainage (pattern, integration degree, density and uniformity degree); relief (pattern, dissection degree and crest lines); photographic texture, photographic tonnality, and the land use (type, glebas size and intensity of use). The performance of the imagery as an auxiliar tool in the soil survey processes, at Rio Grande do Norte State was evaluated. The drainage and relief elements were easily extracted from the imagery and also ones that provided the greatest deductive possibility about pedologic boundaries. Other analyzed criteria were considered only auxiliaries, corroborating some soil limits in the evidences convergence phase. The principal pedologic dominions of the 30,000 sq km are covered by the same LANDSAT image (WRS 359/16) were delimited with good precision: (1) fluvial plains, beaches, dunes and coastal mangroves; (2) North Coast line Plateau; (3) Acu Sandstone Zone; (4) residual plateaus of the Tertiary; and (6) plains of the embasement.

Formaggio, A. R.↗
NASA NTRS1984

The origin and evolution of terrestrial and Martian rock labyrinths

The morphological characteristics and evolutionary development of rock labyrinths on Earth (in sandstone, volcanics, and carbonates) are compared with those on Mars. On Earth rock labyrinths originate as parallel, an echelon, or intersecting narrow grabens, or develop where fault and joint networks are selectively eroded. Labyrinths frequently contain both downfaulted and erosional elements. Closed labyrinths contain depressions; open labyrinths do not, they are simple part of a fluvial network generally of low order. As closed labyrinths made up of intersecting grabens or made up of connected erosional depressions are extremely common on Mars, the research focussed on an understanding of these labyrinth types. Field investigations were carried out in Canyonlands National Park, Utah, and in the Chirachahua Mountains of Arizona. Martian labyrinths were investigated using Viking orbiter images. In addition, research was undertaken on apparent thermokarst features in Lunae Planum and Chryse Planitia where closed depressions are numerous and resemble atlas topography.

Brook, G. A.↗
NASA NTRS1985

Crustal dynamics studies in China

Geodynamics of Mainland China and Taiwan are discussed. The following research was performed: (1) the tectonics along the Tanlu fault in eastern China; (2) tectonics in the Taiwan Strait behind the collision zone in Taiwan; and (3) analysis of faulting in the vicinity of the Altyn Tagn fault. It is found that the existence of the fault is traced back to at least Jurassic with the deposition of conglomerate sandstones in the troungh along the present Tanlu fault branches in the Shantung Province. Taiwan is the product of collision between the Phillipine plate and the Asian plate and Taiwan came into being because of a former island arc.

Wu, F. T.↗