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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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Aqueous weathering is not necessary for formation of the martian soils. The chemical composition and oxidation state of the surface fines can be attributed to meteoritic influx. Additional information is contained in the original extended abstract.
A large albite crystal was found in a Kaidun thin section. The clast is the second alkaline rock found in meteorites. Additional information is contained in the original extended abstract.
A Raman survey on a flat-sawn rock slab provides the major mineralogy of martian meteorite Los Angeles. Three unreported accessory minerals and seven terrestrial alteration products and contaminants (organic and inorganic) were also found. Additional information is contained in the original extended abstract.
Martian meteorite EETA79001 contains abundant Fe-Ti oxides, which yield Raman spectra useful for the assignment of their structural and compositional features. Additional information is contained in the original extended abstract.
Martian meteorites show evidence of oxidation, but putative Noachian organic materials should be accessible. Additional information is contained in the original extended abstract.
Interstellar gas and dust comprise the primary material from which the solar system formed. Evidence that some of this material was organic in nature and survived incorporation into the protosolar nebula is provided by the presence of deuterium-enriched organics in meteorites and interplanetary dust particles. Once the inner planets had sufficiently cooled, late accretionary infall of meteoroids and cosmic dust must have seeded them with some of these complex organic compounds. Delivery of such extraterrestrial compounds may have contributed to the organic inventory necessary for the origin of life. Interstellar ices, the building blocks of comets, tie up a large fraction of the biogenic elements available in molecular clouds. In our efforts to understand their synthesis, chemical composition, and physical properties, we report here that a complex mixture of molecules is produced by ultraviolet (UV) photolysis of realistic, interstellar ice analogs, and that some of the components have properties relevant to the origin of life, including the ability to self-assemble into vesicular structures.
Mineralogical and textural evidence from chondritic meteorites for the nature of aqueous fluids on asteroids. Additional information is contained in the original extended abstract.
Los Angeles is a new martian meteorite that expands the compositional range of basaltic shergottites. Compared to Shergotty, Zagami, QUE94201, and EET79001-B, Los Angeles is more differentiated, with higher concentrations of incompatible elements (e.g., La) and a higher abundance of late-stage phases such as phosphates and K-rich feldspathic glass. The pyroxene crystallization trend starts at compositions more ferroan than in other martian basaits. Trace elements indicate a greater similarity to Shergotty and Zagami than to QUE94201 or EET79001-B, but the Mg/Fe ratio is low even compared to postulated parent melts of Shergotty and Zagami. Pyroxene in Los Angeles has 0.7-4-microns-thick exsolution lamellae, approx. 10 times thicker than those in Shergotty and Zaganii. Opaque oxide compositions suggest a low equilibration temperature at an oxygen fugacity near the fayafite-magnetitequartz buffer. Los Angeles cooled more slowly than Shergotty and Zagami. Slow cooling, coupled with the ferroan bulk composition, produced abundant fine-grained intergrowths of fayalite, hedenbergite, and silica, by the breakdown of pyroxferroite. Shock effects in Los Angeles include maskelynitized plagioclase, pyroxene with mosaic extinction, and rare fault zones. One such fault ruptured a previously decomposed zone of pyroxferroite. Although highly differentiated, the bulk composition of Los Angeles is not close to the low-Ca/Si composition or the globally wind-stirred soil of Mars.
Barlow (this meeting) has identified two potential source craters for the martian meteorite ALH84001. The craters are at 11.7 deg S, 243.3 deg W (Mare Tyrrhenum site) and 14.0 deg S, 343.5 deg W (Sinus Sabaeus site). As noted by Barlow, both craters lie in the heavily cratered terrain (HCT) and are adjacent to fluvial valleys, Here I explore the fluvial history of these areas based upon the surrounding valley morphology. The most prominent valley network at the Sabaeus site is Evros Vallis. This wide, flat-floored valley is approximately 600 km long with an average width of 2.5 km and a depth of 220 m. The eroded volume of the entire Evros network is approximately 6 x 10(exp 11) cc. This is typical for networks located in the heavily cratered terrain (e.g. Warrego and Parana Valles). Evros is also an isolated valley system. No similar networks are found in the surrounding terrain. Thus it is unlikely that Evros formed as a result of widespread rainfall. A localized water source, such as discharge of a hydrothermal system or localized melting of snowfall, seems more consistent Previous modeling has demonstrated that only hydrothermal systems associated with high permeability subsurfaces can discharge sufficient water to form a valley network. The bulk of the discharge from such systems is consequently low temperature, slightly heated water Precipitation of calcium carbonate by low temperature fluids is consistent with most interpretations of the geochemistry of ALH84001. Available imagery at the Tyrrhenum site is of lesser quality. While eroded units of the HCT are nearby, there are no comparable well developed valley networks at this site. Erosion is instead manifested predominantly as gullies on slopes. This style of erosion suggests that water was not present at this site for the length of time as at the more integrated Sabaeus site. The superposition of fluidized ejecta blankets suggests however that ground water or ground ice was still present at this locality fairly recently, if the chosen crater is indeed correct.
Ru isotopic compositions of magmatic iron meteorites and chondrites overlap with terrestrial Ru at the 0.3 to 0.9 (epsilon) level. Additional information is contained in the original extended abstract.
Nano-diamonds have been identified in IDPs (Interplanetary Dust Particles), micrometeorites, and meteorites. They appear to be depleted in non-cluster IDPs suggesting that some nano-diamonds are not presolar. Additional information is contained in the original extended abstract.
We attempt to model the solidification of groups, IIIAB and IVA magmatic iron meteorites using fractional crystallization. We obtain two parameterizations D(Cu), and D(Ni) as function of S concentrations from experiments, and model trends for Cu vs Ni. Additional information is contained in the original extended abstract.
The Sm-Nd isochron for lunar mare basalt meteorite Dhofar 287A yields T = 3.46 +/- 0.03 Ga and Nd = 0.6 +/- 0.3. Its Rb-Sr isotopic system is severely altered. The basalt is unique, probably coming from an enriched mantle source. Additional information is contained in the original extended abstract.
We report preliminary results for the cosmogenic radionuclides, Cl-36, Al-26, and Be-10 and noble gases in a basaltic shergottite Dhofar 019. We found long terrestrial age of Dhofar 019 even though this meteorite was found in hot desert, Oman. Additional information is contained in the original extended abstract.
We report preliminary results of a set of impact disruption experiments on three ordinary chondrite meteorites. Additional information is contained in the original extended abstract.
New cross section measurements for reactions induced by neutrons with energies greater than 70 MeV are used to calculate the production rates for cobalt isotopes in meteorites and these new calculations are compared to previous estimates. Additional information is contained in the original extended abstract.
The functional group distribution of the Tagish Lake meteorite organic solid is characterized with solid state 13C NMR. It is observed that the Tagish contains a broad range of other organic functionality. The Tagish Lake data are compared with Murchison data. Additional information is contained in the original extended abstract.
The isotopic analyses of sugar related compounds from carbonaceous meteorites are described. Additional information is contained in the original extended abstract.