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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,279 records · Page 71
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Landsat in the search for Appalachian hydrocarbons

A study has been conducted to determine the applicability of enhanced Landsat imagery for oil and gas exploration in Appalachia. Attention was given to the feasibility to employ lineaments identified on Landsat imagery as a tool in petroleum exploration. Lineaments, as defined in this connection, are linear or sublinear traces seen on Landsat imagery. They frequently reflect subsurface geological structures. The investigation was conducted in two stages. The first was designed to identify the specific Landsat imagery enhancement best suited for displaying lineaments. The second stage consisted of plotting lineaments and conducting an analysis of the lineament trends with regard to both local geological structure and regional tectonics. A close relationship was observed between lineaments identified on Landsat imagery and known oil and gas reservoirs. This result suggests that lineaments can be related to the structural control of oil and gas reservoirs throughout Appalachia.

Blodget, H. W.↗
NASA NTRS1982

An equivalent layer magnetization model for the United States derived from satellite altitude magnetic anomalies

Long wavelength magnetic anomalies measured by the Pogo series satellites at altitudes 400-700 km over the United States and adjacent areas are inverted to an equivalent layer magnetization model based on an equal area dipole source array at the earth's surface. Minimum source spacing giving a stable solution and a physically meaningful magnetization distribution is 300 km, and a scheme is presented for effectively sampling the distribution on a grid twice as fine. The model expresses lateral variation in the vertical integral of magnetization and is a starting point for models of lateral variation in the form of the magnetization-depth curve in the magnetic crust. The magnetization model contours correlate with large-scale tectonic features, and in the western part of the country, probably reflect Curie isotherm undulations.

Mayhew, M. A.↗
NASA NTRS1982

The intercrater plains of Mercury and the Moon: Their nature, origin and role in terrestrial planet evolution. Thermal histories of Mercury and the Moon

To determine a planet's thermal history, a wide range of data is necessary. These data include remote sensing results, photogeologic evidence, magnetic field and remanent magnetization data, composition and ages of samples, and physical parameters of the planet and its orbit. Few of these data form unambiguous constraints for thermal models of Mercury. Igneous Chronology as the time history of the differentiation and igneous activity, is defined. Igneous Chronology is used here in the sense of the apparent igneous or relative chronology of geologic events, such as plains formation (through whatever mechanism) relative to the crater production and tectonic history (lineament and scarp formation).

Leake, M. A.↗
NASA NTRS1982

The intercrater plains of Mercury and the Moon: Their nature, origin and role in terrestrial planet evolution. Chronology of surface history of Mercury

Phases in the history of the planet Mercury include: (1) condensation and accretion; (2) heating; (3) planetary expansion during heavy bombardment; (4) tidal spin-down and lineament formation; (5) P5 plains emplacement; (6) P4 plains emplacement; (7) peak planetary volume in P3 period; (8) scarp formation; (9) Caloris Basin formation, late class 3; (10) scarp formation and P2 plains formation; (11) smooth plains formation in and around large basins; (12) late or local tectonic stress; and (13) quiescent class 1 period. Although the cooling and contraction of the lithosphere are complete, the core remains molten as an active dynamo, producing the magnetic fields detected by Mariner 10. Plains produced since core formation (P3 to P-1) should record its magnetic activity. Cratering during the Class 2 and Class 1 periods is probably not enough to distribute ballistic materials and homogenize any color differences.

Leake, M. A.↗
NASA NTRS1982

The intercrater plains of Mercury and the Moon: Their nature, origin and role in terrestrial planet evolution. Chronology of surface history of the Moon

The sequence of events is described that occurred from the time that the ancient lunar crust solidified (about 4.4. billion years ago) and anorthositic high lands dominated the surface, until the global contraction (cooling) that began around 3.3 billion years ago when late stage basalts were emplaced at basin margins where fractures penetrated to subsurface tensional zones. The lunar intercrater plains may be linked with early KREEP volcanism, the LKFM basalt source region, and the first stages of mare volcanism. Ages of KREEP bracket the possible ages of the pre-Imbrian plains, and overlap the initial stages of mare basalt emplacement. Both plains are extruded under the same tensional tectonic regime.

Leake, M. A.↗
NASA NTRS1982

Gravity and magnetic anomaly data analysis

Progress on the analysis MAGSAT data is reported. The MAGSAT data from 40 deg S to 70 deg N latitude and 30 deg W to 60 E longitude was reduced to radial polarization. In addition, gravity anomaly data from this area were processed and a variety of filtered maps were prepared for combined interpretation of the gravity and magnetic data in conjunction with structural and tectonic maps of the area. The VERSATEC listings and cross-reference maps of variable and array names for the spherical Earth analysis programs NVERTSM, SMFLD, NVERTG, and GFLD were also prepared.

Braile, L. W.↗
NASA NTRS1982

MAGSAT anomaly field inversion and interpretation for the US

Long wavelength anomalies in the total magnetic field measured by MAGSAT over the United States and adjacent areas are inverted to an equivalent layer crustal magnetization distribution. The model is based on an equal area dipole grid at the Earth's surface. Model resolution, defined as the closest dipole spacing giving a solution having physical significance, is about 220 km for MAGSAT data in the elevation range 300-500 km. The magnetization contours correlate well with large scale tectonic provinces. A higher resolution (200 km) model based on relatively noise free synthetic "pseudodata" is also presented. Magnetic anomaly component data measured by MAGSAT is compared with synthetic anomaly component fields arising from an equivalent source dipole array at the Earth's surface generated from total field anomaly data alone. An excellent inverse correlation between apparent magnetization and heat flow in the western U.S. is demonstrated. A regional heat flow map which is presented and compared with published maps, predicts high heat flow in Nebraska and the Dakotas, suggesting the presence of a "blind" geothermal area of regional extent.

Mayhew, M. A.↗
NASA NTRS1983

The intermediate wavelength magnetic anomaly field of the north Pacific and possible source distributions

A technique that eliminates external field sources and the effects of strike aliasing was used to extract from marine survey data the intermediate wavelength magnetic anomaly field for (B) in the North Pacific. A strong correlation exists between this field and the MAGSAT field although a directional sensitivity in the MAGSAT field can be detected. The intermediate wavelength field is correlated to tectonic features. Island arcs appear as positive anomalies of induced origin likely due to variations in crustal thickness. Seamount chains and oceanic plateaus also are manifested by strong anomalies. The primary contribution to many of these anomalies appears to be due to a remanent magnetization. The source parameters for the remainder of these features are presently unidentified ambiguous. Results indicate that the sea surface field is a valuable source of information for secular variation analysis and the resolution of intermediate wavelength source parameters.

Labrecque, J. L.↗
NASA NTRS1982

The MAGSAT project in Australia

The first version of the MAGSAT selection and reduction software was completed as well as a major enhancement to support geomagnetic vector data selection and reduction. All MAGSAT data over an area between 90 E and 180 E and between 0 and 50 S were reduced. This area includes the Australasian region and surrounding oceans. Nearly 200 profiles across Australia satisfied the criteria for data. The reduced geomagnetic field inferred to be caused by sources within the lithosphere was interpreted. During reduction, magnetic effects caused by all other causes were eliminated. Some possible correlation with major tectonic structures and known continental scale heat flow anomalies were noted.

Source record↗
NASA NTRS1982

Reports of Planetary Geology Program, 1982

Work conducted in the Planetary Geology program is summarized. The following categories are presented: outer solar system satellites; asteroids and comets; Venus; cratering processes and landform development; volcanic processes and landforms; aolian processes and landforms; fluvial processes and landform development; periglacial and permafrost processes; structure, tectonics and stratigraphy; remote sensing and regolith studies; geologic mapping, cartography and geodesy.

Holt, H. E.↗
NASA NTRS1982

Application of MAGSAT to lithospheric modeling in South America

Progress continues on all aspects of the project. The prime emphasis is on the Rayleigh wave study and determination of both group and phase velocity dispersion is almost complete. Existing data sets were prepared for inversion. A paper on the relation of MAGSAT anomalies to the main tectonic provinces of South America was delivered at the annual meeting of the Society of Exploration Geophysicists.

Keller, G. R.↗
NASA NTRS1982

An investigation of MAGSAT and complementary data emphasizing precambrian shields and adjacent areas of West Africa and South America

Some MAGSAT data and preliminary results emphasizing Africa, Latin America, and the Caribbean were presented to geologists in Jamaica, Guyana, Brazil, and Argentina who then expressed interest in collaborating on linking computer modeling of MAGSAT data to tectionic and metallogenic interpretation for South America and in making the final interpretation. Modeling continues with the preparation of a synopsis tectonic map of South America and the initiation of semi-final modeling of northern South America.

Hastings, D. A.↗
NASA NTRS1982

MAGSAT scalar anomalies

To facilitate processing large data arrays, elements of spherical Earth analysis programs NVERTSM, SMFLD, NVERTG and GLFD were implemented and tested on the LARS IBM 4341 computer. Currently, the problem of inverting 2 deg MAGSAT scalar anomalies for the region (80 W, 60 E) longitude and (40 S, 70 N) latitude is being implemented on the LARS-computer for quantitative comparison with free air gravity anomaly, geothermal and tectonic data. Gravity and MAGSAT anomalies from a subset of this region (30 W, 60 E), (40 S, 70 N) were already processed for a paper on satellite magnetic anomalies of Africa and Europe.

Braile, L. W.↗
NASA NTRS1982

Satellite elevation magnetic anomaly maps

The problem of inverting 2 deg average MAGSAT scalar anomalies for the region 80 W, 60 E longitude and 40 S, 70 N latitude was attempted on the LARS computer; however, the effort was aborted due to insufficient allocation of CPU-time. This problem is currently being resubmitted and should be implemented shortly for quantitative comparison with free-air gravity anomaly, geothermal, and tectonic data.

Braile, L. W.↗
NASA NTRS1983

MAGSAT investigation of crustal magnetic anomalies in the eastern Indian Ocean

Crustal magnetic anomalies in a region of the eastern Indian Ocean were studied using data from NASA's MAGSAT mission. The investigation region (0 deg to 50 deg South, 75 to 125 deg East) contains several important tectonic features, including the Broken Ridge, Java Trench, Ninetyeast Ridge, and Southeast Indian Ridge. A large positive magnetic anomaly is associated with the Broken Ridge and smaller positive anomalies correlate with the Ninetyeast Ridge and western Australia. Individual profiles of scalar data (computed from vector components) were considered to determine the overall data quality and resolution capability. A set of MAGSAT ""Quiet-Time'' data was used to compute an equivalent source crustal magnetic anomaly map of the study region. Maps of crustal magnetization and magnetic susceptibility were computed from the equivalent source dipoles. Gravity data were used to help interpretation, and a map of the ratio of magnetization to density contrasts was computed using Poisson's relation. The results are consistent with the hypothesis of induced magnetization of a crustal layer having varying thickness and composition.

Sailor, R. V.↗
NASA NTRS1982

Remanent magnetization and three-dimensional density model of the Kentucky anomaly region

Existing software was modified to handle 3-D density and magnetization models of the Kentucky body and is being tested. Gravity and magnetic anomaly data sets are ready for use. A preliminary block model is under construction using the 1:1,000,000 maps. An x-y grid to overlay the 1:2,500,000 Albers maps and keyed to the 1:1,000,000 scale block models was created. Software was developed to generate a smoothed MAGSAT data set over this grid; this is to be input to an inversion program for generating the regional magnetization map. The regional scale 1:2,500,000 map mosaic is being digitized using previous magnetization models, the U.S. magnetic anomaly map, and regional tectonic maps as a guide.

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