[meteorite-list] Reclassification of ALH 84001 (was: Question about olivine diogenites)

From: bernd.pauli at paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: 11 Jun 2010 21:15:28 UT
Message-ID: <DIIE.0000001500004BC9_at_paulinet.de>

Hello List,

Here are some of the criteria that led to the reclassification of ALH 84001
that was originally classified as a diogenite, or, to put it in D.W. Mittle-
fehldt's words: "... had been masquerading as a diogenite in the Antarctic
meteorite collection since 1985."

- oxygen isotopic measurements by R. Clayton (1993)
- abundant ferric iron
- sodic maskelynite
- pyrite (instead of troilite)
- relatively fine grain size, and carbonates

References:

P.H.Warren (1994) A carbonate-rich piece of Mars disguised
as a diogenite (Meteoritics 29-2, 1994, 152-153).

D.W.Mittlefehldt (1994) ALH 84001, A cumulate orthopyroxenite
member of the Martian meteorite clan (Meteoritics 29-2, 1994,
pp. 214-221, Errata: Meteoritics 29, 1994, 900).


Best wishes,

Bernd
Received on Fri 11 Jun 2010 05:15:28 PM PDT