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Two chondrule groups each with distinctive rims in Murchison recognized by cathodoluminescenceTwo groups of chondrules in the Murchison CM chondrite, which have previously been identified on the basis of FeO in the chondrule grains, are readily identified from cathodoluminescence (CL) and belong to those of the ordinary chondrite group A and B chondrules of Sears et al. (1992a). All chondrules are surrounded by fine-grained rims containing forsterite with bright red CL, but on group A chondrules an outer thin rim grades into a much thicker rim, with a lower density of forsterite grains, which in turn grades into the central chondrule. Group B chondrules have only the thin outer rim with a high density of small forsterite grains. This is the first time an unequivocal correlation has been observed between chondrule rim thickness and the composition of the object on which the rim is located. We suggest that while all objects in the meteorite (group B chondrules, refractory inclusions, mineral and chondrule fragments, clasts) acquired a very thin rim during processing in a wet regolith, the thick rims on group A chondrules were formed by aqueous alteration of precursor metal- and sulfide-rich rims which are a characteristic of group A chondrules in ordinary chondrites.
Document ID
19950047183
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Sears, Derek W. G.
(University of Arkansas, Fayetteville, AR United States)
Benoit, Paul H.
(University of Arkansas, Fayetteville, AR United States)
Jie, LU
(University of Arkansas, Fayetteville, AR United States)
Date Acquired
August 16, 2013
Publication Date
December 1, 1993
Publication Information
Publication: Meteoritics
Volume: 28
Issue: 5
ISSN: 0026-1114
Subject Category
Lunar And Planetary Exploration
Accession Number
95A78782
Funding Number(s)
CONTRACT_GRANT: NAG9-81
Distribution Limits
Public
Copyright
Other

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