Keywordscomposition of meteorites
CK carbonaceous chondrite meteorites
R chondrite meteorites
MetadataShow full item record
CitationRubin, A. E., & Huber, H. (2005). A weathering index for CK and R chondrites. Meteoritics & Planetary Science, 40(8), 1123-1130.
PublisherThe Meteoritical Society
JournalMeteoritics & Planetary Science
AbstractWe present a new weathering index (wi) for the metallic-Fe-Ni-poor chondrite groups (CK and R) based mainly on transmitted light observations of the modal abundance of crystalline material that is stained brown in thin sections: wi-0, <5 vol%; wi-1, 5-25 vol%; wi-2, 25-50 vol%; wi-3, 50-75 vol%; wi-4, 75-95 vol%; wi-5, >95 vol%; wi-6, significant replacement of mafic silicates by phyllosilicates. Brown staining reflects mobilization of oxidized iron derived mainly from terrestrial weathering of Ni-bearing sulfide. With increasing degrees of terrestrial weathering of CK and R chondrites, the sulfide modal abundance decreases, and S, Se, and Ni become increasingly depleted. In addition, bulk Cl increases in Antarctic CK chondrites, probably due to contamination from airborne sea mist.