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Record Details

Record 15 of 1874
Petrogenesis of the nakhlite meteorites - Evidence from cumulate mineral zoning
External Online Source: doi:10.1016/0016-7037(92)90232-8
Author and Affiliation:
Harvey, Ralph P.(NASA Lyndon B. Johnson Space Center, Houston, TX, United States)
Mcsween, Harry Y., Jr.(Tennessee, University, Knoxville, United States)
Abstract: Attention is given to a simple igneous petrogenesis for the meteorite Nakhla, which was previously called into question because Mg/Fe ratios in olivine indicate substantial disequilibrium between the predominant cumulus minerals (olivine and augite). Comparative analyses of simulated diffusive zoning and the observed cumulus mineral zoning for all three nakhlites (Nakhla, Governador Valadares, and Lafayette) show that their current compositions do not necessarily reflect parental magma compositions. Diffusion has altered primary cumulus compositions to varying degrees, Nakhla being the least affected, and Lafayette being almost completely reequilibrated. Since mineral zoning in each meteorite is strongly concentric around mesostasis areas, it is inferred that reaction with intercumulus liquid has controlled the observed zoning. It is argued that the nakhlites appear to be a series of relatively simple cumulate rocks which have undergone various amounts of late-magmatic and subsolidus diffusion, possibly reflecting their relative positions in a cooling cumulate pile.
Publication Date: Apr 01, 1992
Document ID:
19920051229
(Acquired Nov 22, 1995)
Accession Number: 92A33853
Subject Category: LUNAR AND PLANETARY EXPLORATION
Document Type: Journal Article
Publication Information: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 56; 1655-166
Publisher Information: United Kingdom
Contract/Grant/Task Num: NAG9-58
Financial Sponsor: NASA; United States
Organization Source: NASA Johnson Space Center; Houston, TX, United States
Description: 9p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: IGNEOUS ROCKS; METEORITIC COMPOSITION; NAKHLITES; PETROGRAPHY; CHEMICAL COMPOSITION; CHEMICAL EVOLUTION; MARS SURFACE; OLIVINE
Imprint And Other Notes: Geochimica et Cosmochimica Acta (ISSN 0016-7037), vol. 56, April 1992, p. 1655-1663.
Availability Source: Other Sources
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