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Accession Number N20130004199
Title Evidence for Extended Aqueous Alteration in CR Carbonaceous Chondrites.
Publication Date 2013
Media Count 2p
Personal Author C. E. Moyano-Cambero J. Fraxedas J. M. Trigo-Rodriquez M. Zolensky N. Mestres T. Nakamura Z. Martins
Abstract We are currently studying the chemical interrelationships between the main rockforming components of carbonaceous chondrites (hereafter CC), e.g. silicate chondrules, refractory inclusions and metal grains, and the surrounding meteorite matrices. It is thought that the fine-grained materials that form CC matrices are representing samples of relatively unprocessed protoplanetary disk materials (1-3). In fact, modern non-destructive analytical techniques have shown that CC matrices host a large diversity of stellar grains from many distinguishable stellar sources (4). Aqueous alteration has played a role in homogeneizing the isotopic content that allows the identification of presolar grains (5). On the other hand, detailed analytical techniques have found that the aqueously-altered CR, CM and CI chondrite groups contain matrices in which the organic matter has experienced significant processing concomitant to the formation of clays and other minerals. In this sense, clays have been found to be directly associated with complex organics (6, 7). CR chondrites are particularly relevant in this context as this chondrite group contains abundant metal grains in the interstitial matrix, and inside glassy silicate chondrules. It is important because CR are known for exhibiting a large complexity of organic compounds (8-10), and only metallic Fe is considered essential in Fischer-Tropsch catalysis of organics (11-13). Therefore, CR chondrites can be considered primitive materials capable to provide clues on the role played by aqueous alteration in the chemical evolution of their parent asteroids.
Keywords Aqueous solutions
Carbonaceous chondrites
Fischer-tropsch process
Grain size
Organic materials
Scanning electron microscopy

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 54 - Astronomy & Astrophysics
84B - Extraterrestial Exploration
Corporate Author National Aeronautics and Space Administration, Houston, TX. Lyndon B. Johnson Space Center.
Document Type Conference proceedings
Title Note N/A
NTIS Issue Number 1319
Contract Number N/A

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