Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “MINERALOGY”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34

Mineralogic and petrologic study of the low-temperature minerals in carbonaceous chondrites

Samples and petrographic thin sections of the Orgueil, Ivuna, and Alais chondrites were examined by optical, X-ray, and SEM techniques. Mineral species identified as primary vein constituents were epsomite, gypsum, and a calcium-magnesium carbonate. Relative abundances and textural relationships have suggested that fracture mineralization was a multi stage process, with individual mineralizations closely associated with impact brecciation events. Mass balance considerations of carbonaceous chondrite matrix support the prevailing view that the source of the fracture filling minerals was local. By inference they also suggest that the phyllosilicate matrix has been chemically altered and that there are probably very few primitive mineral phases in the primitive Cl chondrites.

Wood, J. A.↗

Mare basalts - Crystal chemistry, mineralogy, and petrology

The paper attempts a synthesis of the major-element chemistry, petrography, mineral chemistry, and crystal chemistry of the mare basalts returned by Apollo and Luna missions. A classification of the mare basalts based on major-element chemistry is given, and textural sequences within each major-element group are identified. The mineral chemistry and crystal chemistry of each mineral group are considered within the framework of the major-element groups and the textural sequences. The various classes of models for the origin of the mare basalts and the nature of their source regions are discussed in the context of the major- and trace-element chemistries and experimental investigations.

Papike, J. J.↗

Asteroid surface materials: Mineralogical characterizations from reflectance spectra

Mineral assemblages analogous to most meteorite types, with the exception of ordinary chondritic assemblages, have been found as surface materials of Main Belt asteroids. C1- and C2-like assemblages (unleached, oxidized meteoritic clay minerals plus opaques such as carbon) dominate the population throughout the Belt, especially in the outer Belt. A smaller population of asteroids exhibit surface materials similar to C3 (CO, CV) meteoritic assemblages (olivine plus opaque, probably carbon) and are also distributed throughout the Belt. The majority of remaining studied asteroids (20) of 65 asteroids exhibit spectral reflectance curves dominated by the presence of metallic nickel-iron in their surface materials. The C2-like materials which dominate the main asteroid belt population appear to be relatively rare on earth-approaching asteroids.

Gaffey, M. J.↗

Petrology, mineralogy and chemistry of KREEP basalt

KREEP basalt is an important lunar material that was formed in large quantities early in the evolutionary history of the moon. Fragments of KREEP basalt were returned from all landing sites and make up most of the material of the Apollo 14 collection. These fragments have a wide variety of textures caused by various secondary processes but they are all characterized by a large and distinctive trace-element content. They are also characterized by a general basaltic composition that is similar to the olivine-plagioclase-pyroxene peritectic in the system silica-anorthite-olivine (Fe/Fe + Mg = 0.3).

Meyer, C., Jr.↗

Temperature dependence of Fe/++/ crystal field spectra - Implications to mineralogical mapping of planetary surfaces

Results are reported of Fe(++) crystal field spectral measurements for olivines and pyroxenes up to 400 C. The results are correlated with crystal structure data at elevated temperatures, and the validity of remote-sensed identifications of minerals on hot surfaces of the moon and Mercury is assessed. Two techniques were used to obtain spectra of minerals at elevated temperatures using a spectrophotometer. One employed a diamond cell assembly or a specially designed sample holder to measure polarized absorption spectra of heated single crystals. For the other technique, a sample holder was designed to attach to a diffuse reflectance accessory to produce reflectance spectra of heated powdered samples. Polarized absorption spectra of forsterite at 20-400 C are shown in a graph. Other graphs show the temperature dependence of Fe(++) crystal field bands in olivines, the diffuse reflectance spectra of olivine at 40-400 C, the polarization absorption spectra of orthopyroxene at 30-400 C, the diffuse reflectance spectra of pigeonite at 40-400 C, and unpolarized absorption spectra of lunar pyroxene from Apollo 15 rock 15058.

Sung, C.-M.↗

Apollo 15 breccia rake samples - Mineralogy of lithic and mineral clasts

Major features of 22 Apollo 15 breccia rake samples and 30 lithic clasts in these samples are described. The range of compositions of exsolved pyroxene grains (bulk and individual lamellae) indicates a slowly cooled mare basalt source. In terms of these data the pyroxenes closely resemble pyroxenes in large anorthosite 67075. It is suggested that the pyroxene-plagioclase-olivine clast in 15146 as well as some anomalous chemical data might result from metamorphism of a mare-type basalt or from plutonic crystallization of magma with mare basalt affinity. The bulk composition of the clast in 15146 closely matches that of Apollo 15 'green glass' to which it may be related. A unique ultrabasic clast in 15360 has an unusually low CaO content and other chemical features which suggest that this sample is unlike ultrabasic samples described to date.

Steele, I. M.↗

Lunar Science Conference, 6th, Houston, Tex., March 17-21, 1975, Proceedings. Volume 1 - Mineralogical and petrological studies. Conference sponsored by NASA and Lunar and Planetary Institute

This book represents a conference whose main topics include: petrological studies of lunar samples, studies of anorthositic rocks, studies of soils and breccias, lunar minerology, petrologic studies of lunar problems, and petrogenetic models of lunar evolution. Attention is given to samples obtained from the Apollo 16 and 17 missions.

Merrill, R. B.↗

Studies of Brazilian meteorites. XIII - Mineralogy, petrology, and chemistry of the Putinga, Rio Grande do Sul, chondrite

The Putinga, Rio Grande do Sul chondrite is described and classified as an L6. The mineral composition and some significant ratios of elements are reported, and the reasons for assignment to the L group and to petrologic type 6 are explained. The analysis suggests that maskelynite of oligoclase composition was formed by solid-state shock transformation of previously existing well-crystallized plagioclase at estimated shock pressures of about 250-350 kbar. This finding indicates that recrystallization (formation of well-crystallized oligoclase) preceded shock transformation formation of the maskelynite.

Keil, K.↗

Studies of Brazilian meteorites. XIV - Mineralogy, petrology, and chemistry of the Conquista, Minas Gerais, chondrite

The Conquista chondrite is described and classified as an H4. The mineral composition is reported. H-group classification is based on described microscopic, electron microprobe, and bulk chemical studies. The evidence for petrologic type 4 classification includes the pronounced well-developed chondritic texture; the slight compositional variations in constituent phases; the high Ca contents of pyroxene and the presence of pigeonite; glassy to microcrystalline interstitial material rich in alkalis and SiO2; and twinned low-Ca clinopyroxene.

Keil, K.↗

Thermal metamorphism of primitive meteorites. VII - Mineralogy-petrology of heated Murchison /C2/ and alteration of C30 and other chondrites

Alterations caused by week-long heating of Murchison in a low-pressure environment at 400-1400 C are of two types: thermodynamically favored kinetically controlled or thermodynamically controlled rapid processes. Kinetically controlled changes pertinent to chondritic evolution and which vary progressively with temperature in heated Murchison include: chondrule blurring; matrix coarsening; increasing mean Fa and Fs contents of ferromagnesian silicates; equilibration of olivine; increasing Mg/Si, Ca/Si, Al/Si, and Cr/Si and decreasing Fe/Si, Ni/Si, and S/Si in matrix; Cr loss from kamacite; and homogenization and Ni-zoning in taenite at high temperatures. Low-temperature thermodynamically controlled changes include: transformation of high-Ni troilite to low-Ni and formation of Ni- and Co-rich metal from pentlandite. High-temperature changes include formation of Cr-rich magnetite and formation of a Ni-rich sulfide similar to that found in highly altered chondrites. Trends resulting from processes of both kinds in Murchison are consistent with characteristics of a postulated C30 metamorphic suite, while those changes caused by reactions of the second kind are similar to those in heavily shock-heated ordinary chondrites and the heavily metamorphosed C5-6 chondrite, Mulga West. Either the simulations support the metamorphic origin of the C30 suite and other thermally induced changes or the natural alterations support the utility of laboratory simulations in studying meteoritic evolution.

Matza, S. D.↗