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Adams, J. B.

Publications and source records attributed to Adams, J. B..

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Geological remote sensing: Identification and mapping of rock types for non-renewable resources

Efforts concentrated on developing a technique for relating laboratory spectral reflectance curves of known rocks and vegetation on LANDSAT multispectral images. The techniques involves determination of the laboratory spectral signature of a material of interest and searching a stack of spatially registered multispectral images for materials with the desired spectral signature. Changes in spectral reflectance caused by vegetation cover were also investigated in surface samples from Hawaii.

Adams, J. B.↗
NASA NTRS1980

Late high-titanium basalts of the western maria - Geology of the Flamsteed region of Oceanus Procellarum

The evolution, geology, geochemistry and topology of the Flamsteed region of Oceanus Procellarum are examined, considering remote sensing data including multispectral images and spectral reflectance measurements along with crater degradation studies and radar backscatter. Seven spectrally distinct basaltic units ranging in age from 2.5 plus or minus 0.5 to 3.5 plus or minus 0.5 billion years have been identified. The earliest units of the mapped area are composed of highlands material and include partially flooded impact craters, and the oldest surface exposed mare basalts are very low Ti basalts of the Telemann formation.

Pieters, C. M.↗
NASA NTRS1979

Mars surface composition from reflectance spectroscopy - A summary

Visible and near-infrared reflectance spectra and multispectral maps of the Martian surface are discussed, and implications of the data for the composition of the Martian surface are considered. Spacecraft and earth-based telescopic observations have confirmed the generally bimodal albedo distribution of the planet, dividing the surface into bright and dark regions. Mars spectra are characterized by the presence of strong Fe(+3) absorption, which is attributed to various ferric oxide minerals. Interpretations of the spectra from the dark regions indicate a basaltic or ultramafic source rock. Evidence for water ice or a highly desiccated metal hydrate has been obtained, along with evidence for CO2-ice only in the south polar cap. Mariner 9 observations of Martian dust suggest the presence of rather acidic rock or mineral particles, or a montmorillonite-type clay. Prospects for the future study of Martian surface composition include continuing earth-based spectrophotometric studies, and high-spectral-resolution mapping of a significant portion of the surface by the Galileo spacecraft and the next Mars mission.

Singer, R. B.↗
NASA NTRS1979

Mare Crisium geologic units - Implications of additional remote sensing data

Additional spectral reflectance data are presented for the Mare Crisium region. This new remote sensing information supports and supplements the subdivision of Mare Crisium into three major basalt units and shows further that: (1) the Luna 24 landing site is on a small region apparently surrounded by distinctly different units, but is clearly correlated with basalt Group IIA of Head et al. (1978); (2) exposures of Group IIB basalt in the northern and southern parts of the basin are spectrally similar; and (3) Group I basalts along the eastern part of the basin, which have been proposed to be relatively young (Boyce and Johnson, 1977), are spectrally similar to older Group I basalts.

Pieters, C. M.↗
NASA NTRS1979

Multispectral mapping of the Apollo 15-Apennine region - The identification and distribution of regional pyroclastic deposits

Multispectral mapping of the Apollo 15-Apennine region has allowed the identification of numerous dark mantle deposits of probable pyroclastic origin. The deposits display a low albedo, appear to mantle and slightly subdue subjacent terrain, are spectrally distinct on the multispectral maps (high in the infrared but low in the ultraviolet) and generally exhibit a weak depolarized 3.8 cm radar echo. These characteristics are consistent with an origin by pyroclastic eruption. The regional dark mantle deposits are commonly associated with vents along marginal fractures and faults near the base of the Apennines, thereby emphasizing the role of basin-controlled weaknesses in providing channels for the upward migration of magma generated at depth. The spectral properties of the pyroclastic deposits are incompatible with those of Apollo 15 green glass but the deposits may be composed of material similar to the Apollo 15 brown or yellow glass. If so, the widespread distribution of the deposits suggest that mare basalts genetically related to the brown or yellow glass may occur in the Apollo 15 region. Moreover, pyroclastic volcanic activity has apparently been a more important and widespread process in the Apollo 15-Apennine region than has previously been thought.

Hawke, B. R.↗
NASA NTRS1978

Mare Crisium - Regional stratigraphy and geologic history

Spectral reflectance measurements of five Luna 24 samples and new telescopic reflectance spectra of 10-20 km areas of seven sites in Mare Crisium have been used to calibrate multispectral images of mare units. Based on these data, three major mare units are defined in the Crisium basin and their stratigraphy is interpreted. The oldest mare unit is exposed in the ejecta of the craters Picard and Peirce and along the outer edge of the southeastern part of the basin. The next younger unit includes the Luna 24 site and generally follows a topographic annulus along the basin margin. The youngest mare unit occupies the central part of the basin. It is concluded that subsidence occurred throughout the emplacement of mare units, including extensive warping and downfaulting of the inner part of the Crisium basin.

Adams, J. B.↗
NASA NTRS1978

Regional stratigraphy and geologic history of Mare Crisium

Remote sensing and Luna 24 sample data are used to develop a summary of the regional stratigraphy and geologic history of Mare Crisium. Laboratory spectra of Luna 24 samples, telescopic reflectance spectra in the 0.3 to 1.1 micron range and orbital X-ray data have identified three major basalt groups in the region. Group I soil is derived from iron- and magnesium-rich titaniferous basalts and was apparently emplaced over the majority of the basin, however is presently exposed as a shelf in the southwest part. Group II soils, derived from very low titanium ferrobasalts, were emplaced in two stages subsequent to Group I emplacement and now appear as part of the outer shelf and topographic annulus. Subsidence of the basin interior preceded and continued after the emplacement of the third basalt group, a soil derived from a low titanium ferrobasalt. The Luna 24 site is found to be within a patch of Group II material.

Head, J. W., III↗
NASA NTRS1978

Plagioclase feldspars - Visible and near infrared diffuse reflectance spectra as applied to remote sensing

Visible and near IR diffuse reflectance spectra of plagioclase feldspars are characterized by absorption features caused by minor amounts of Fe(2+) that occur bound in the crystal structure. It is found that identification of terrestrial feldspars by remote sensing appears to be feasible for the compositional range An50 to An80, providing that other minerals do not mask the feldspar signatures. Determination of plagioclase composition using the wavelength of the Fe(2+) band may be possible for lunar samples, where the plagioclase can be assumed to be more calcic than An65.

Adams, J. B.↗
NASA NTRS1977

Use of ground-based telescopes in determining the composition of the surfaces of solar system objects

Recent evidence suggests that the way that the surfaces of the solar system objects reflect solar radiation is controlled by the composition and mineralogy of the surface materials. The way sunlight is reflected from the surface as a function of wavelength, i.e., the spectral reflectance, is the most important property. Laboratory efforts to use ground-based optical telescope measurements to determine the composition of the surfaces of the solar system objects are reviewed.

Mccord, T. B.↗
NASA NTRS1976

Regional basalt types in the Luna 24 landing area as derived from remote observations

The Soviet spacecraft Luna 24 landed in Mare Crisium and returned samples that are expected to be much like the low titanium basalts from Luna 16 and Apollo 12. This conclusion is based on earth-based spectral reflectance measurements and multispectral imagery of the Mare Crisium region and uses a background of laboratory measurements of the spectral properties of Lunar soils. These data are used to describe the regional context and composition of the Crisium basaltic units. The returned sample may also contain minor components of a high-titanium basalt and a very low titanium basalt as well as highland material.

Pieters, C.↗
NASA NTRS1976

Age-color relationships in the lunar highlands

The depth of the absorption feature near 1 micron in the reflectance spectra of immature lunar soils is determined primarily by the amount of pyroxene present in the soil. As a soil matures, the agglutinitic glass content increases and the Fe(2+) glass band dominates the absorption feature. An empirical relationship between the 1 micron band depth and the percentage of magnetic agglutinates, and hence maturity, is demonstrated for mature highland soils of a given composition. A similar variation of 1 micron band depth is observed in the telescopic spectra of lunar highland craters and is positively correlated with the surface maturity as determined by the small-impact erosion model of Soderblom (1970). Knowledge of both maturity and the 1 micron band depth of a lunar surface feature allows compositional information to be derived.

Charette, M. P.↗
NASA NTRS1975

Chemical fractionation of the lunar regolith by impact melting

Impact-produced agglutinitic glass in both lunar highland and mare soils is enriched in mafic elements, in potassium, phosphorus, and sulfur, and in most lithophile elements, whereas it is depleted in plagioclase components including europium. It is proposed that the chemical fractionation is the result of a multistage partial-melting mechanism that accompanies micrometeoroid impacts into soils. The process would be expected to occur on solar system bodies that have an impact-produced regolith.

Adams, J. B.↗
NASA NTRS1975

Effects of maturation on the reflectance of the lunar regolith: Apollo 16 - A case study

Soils at the Apollo 16 site become progressively darker as the percentage of glassy agglutinates increases. Magnetic separates of the agglutinate fraction of a soil are always darker than the bulk soil and are darker than the nonagglutinate fraction consisting of rock and mineral fragments. Darkening of a soil with maturity is due mainly to the increasing proportion of agglutinates. Coating of rock and mineral fragments with thin deposits of glass aids darkening in a minor way, but most of these particles eventually are destroyed by melting as the soils mature.

Adams, J. B.↗
NASA NTRS1975

Agglutinates as indicators of lunar soil maturity - The rare gas evidence at Apollo 16

The weight percent of lunar agglutinic glass (glass-welded aggregates resulting from micrometeorite impacts) in Apollo 16 bulk soils is considered with respect to quantities of trapped rare gases, e.g., He-4, Ne-20, Ar-36, Kr-84, and Xe-132, in an effort to determine the cumulative time a given soil sample has spent exposed on the lunar surface. The agglutinic glass, which reacts strongly in a magnetic field, is obtained by the standard fluid (methanol)-magnetic technique. It is noted that the absolute concentrations of trapped rare gases all show a linear relationship with increasing agglutinic glass content.

Charette, M. P.↗
NASA NTRS1975

Chemistry of agglutinate fractions in lunar soils

Agglutinates are aggregates of crystalline grains and lithic fragments bonded together by glass. It is thought that glassy agglutinates are formed at the upper surface of the lunar regolith by impact-related melting and welding of soil particles, in response to meteoroid and micrometeoroid bombardment. A description is presented of an investigation in which bulk soils were separated into 'agglutinate' and 'nonagglutinate' fractions. The obtained fractions were analyzed for major, minor, and trace elements. The obtained chemical data for agglutinate and nonagglutinate fractions of lunar soils indicate that agglutinitic glass is enriched in mafic and most lithophile elements relative to the bulk soils. A model involving preferential melting and assimilation of mesostasis material and mafic soil components is proposed to account for the observed chemical data. It is suggested that glassy agglutinates may form more readily in mafic soils than in more feldspathic ones. Such selectivity should be most effective between mare and highland soils, but may possibly operate on a more local scale.

Rhodes, J. M.↗