Early aqueous activity on primitive meteorite parent bodies
Article Abstract:
The aqueous alterations on protoplanetary bodies occurred less than 20 Myr after the formation of Allende refractory inclusions. The measurement of 53Cr, formed by the decomposition of 53Mn, in five carbonate fragments from the carbonaceous CI chondrites Orgueil and Ivuna indicates that CI carbonate fragments solidified between 16.3 and 18.3 Myr after Allende calcium-aluminium inclusions. Results show that only few half-lives of this radioisotope passed between the formation of oldest Solar System object and the aqueous activity.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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No 'nanofossils' in martian meteorite
Article Abstract:
Studies suggest that the reported martian 'nanofossils' on the martian meteorite ALH84001 are mainly lamellar growth steps on carbonate crystals and pyroxene, with the segmented surface microstructures primarily a conductive metal coating artefact. Studies of the surface topography over various tilt angles reveal features that are emergent substrate lamellae edges. Most of the meteorite's elongated forms seem to be magnetite whiskers or emergent substrate lamellae, although some parts could feasibly be martian nanofossils.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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Survival of isotopically heterogeneous graphite in a differentiated meteorite
Article Abstract:
Investigations on the nature of graphite grains in Acapulco meteorite indicate that these grains, having differing compositions of carbon and nitrogen, possess the isotopic composition of their precursors. The enhanced temperatures of the asteroid do not affect graphite composition. Several grains of graphite associated with the same metal may possess differing compositions.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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