LIMIT ON THE SCALE OF IMPACT-RELATED METAL/SILICATE SEGREGATION ON L CHONDRITE PARENT(S)

Abstract

To assess the role of impact related reheating on compositional trends in the major elements of the L chondrite parent(s), I examined a suite of 37 L falls analyzed by Jarosewich (1990). After eliminating 8 samples prepared from quantities which differently sampled the chondrites considered, I found that suites of mildly-shocked (S3) and strongly-shocked (S4-S6) equilibrated L chondrite falls can be distinguished at statistically significant levels when compared based on their major element content. Graphical comparisons demonstrated that the differences arise because siderophiles are depleted with corresponding mass-balanced lithophile enrichment in strongly-shocked samples. Since the samples considered here were derived from volumes of between 1.5 cm3 and 4.7 cm3, we can conclude that statistically significant post-metamorphic metal(sulfide)/silicate segregation occurred on a scale of at least this size. Copyright © 2006 by The Geochemical Society of Japan.