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A petrological, mineralogical and chemical analysis of the lunar mare basalt meteorites LaPaz Icefield 02205, 02224 and 02226

Joy, K.H. and Crawford, Ian A. and Downes, Hilary and Russell, S.S. and Kearsley, A.T. (2006) A petrological, mineralogical and chemical analysis of the lunar mare basalt meteorites LaPaz Icefield 02205, 02224 and 02226. Meteoritics and Planetary Science 41 (7), pp. 1003-1025. ISSN 1086-9379.

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Abstract

LaPaz Icefield (LAP) 02205, 02226, and 02224 are paired stones of a crystalline basaltic lunar meteorite with a low-Ti (3.21–3.43% TiO2) low-Al (9.93–10.45% Al2O3), and low-K (0.11–0.12% K2O) composition. They consist mainly of zoned pyroxene and plagioclase grains, with minor ilmenite, spinel, and mesostasis regions. Large, possibly xenocrystic, forsteritic olivine grains (<3% by mode) contain small trapped multiphase melt inclusions. Accessory mineral and mesostasis composition shows that the samples have experienced residual melt crystallization with silica oversaturation and late-stage liquid immiscibility. Our section of LAP 02224 has a vesicular fusion crust, implying that it was at one time located sufficiently close to the lunar surface environment to have accumulated solar-wind-implanted gases. The stones have a comparable major element composition and petrography to low-Ti, low-Al basalts collected at the Apollos 12 and 15 landing sites. However, the LAP stones also have an enriched REE bulk composition and are more ferroan (Mg numbers in the range of 31 to 35) than similar Apollo samples, suggesting that they represent members of a previously unsampled fractionated mare basalt suite that crystallized from a relatively evolved lunar melt.

Item Type: Article
Additional Information: The published version of this article is available to subscribers at http://meteoritics.org/
School or Research Centre: Birkbeck Schools and Research Centres > School of Science > Earth and Planetary Sciences
Depositing User: Sandra Plummer
Date Deposited: 17 Jan 2007
Last Modified: 17 Apr 2013 12:33
URI: http://eprints.bbk.ac.uk/id/eprint/440

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