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A new carbon-rich phase (COPS) in Antarctic micrometeoritesThe contemporary flux of micrometeorites with sizes greater than 50 microns reaching the Earth's surface each year (about 20,000 tons/a) is much greater than the value of approximately 100 tons/a reported for conventional meteorites up to masses of approximately 10,000 tons. Moreover, on the average, Antarctic micrometeorites contain at least as much carbon as does Orgueil, the most C-rich meteorite. Micrometeorites are thus responsible for most of the carbon accreted by the Earth. In this paper we report SEM observations of a new C-rich 'dirty magnetite' phase observed as tiny inclusions in both melted and unmelted micrometeorites. This phase, which is enriched in C, O, P, S, Fe, frequently shows Ni contents in excess of 0.2 percent, strongly suggestive of an 'extraterrestrial' origin. We also discovered this 'COPS' phase in the fusion crust of Murchison. It appears likely that COPS is a product of meteoroid reprocessing during frictional heating in the Earth's atmosphere and/or its fast 'weathering' in the upper atmosphere. Upon 'catalyzed' hydrolysis this phase might have facilitated the functioning of micrometeorites as 'micro-chondritic-reactors' for the synthesis of prebiotic molecules on the early Earth.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Engrand, C.
(Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse Orsay, France)
Maurette, M.
(Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse Orsay, France)
Kurat, G.
(Naturhistorisches Museum Vienna, Austria)
Brandstatter, F.
(Naturhistorisches Museum Vienna, Austria)
Perreau, M.
(Office National d'Etudes et de Recherches Aeronautiques Paris, France)
Date Acquired
September 6, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Lunar and Planetary Inst., Twenty-fourth Lunar and Planetary Science Conference. Part 1: A-F
Subject Category
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.

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