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Clearwater East impact structure: A re‐interpretation of the projectile type using new platinum‐group element data from meteorites
Author(s) -
McDonald Iain
Publication year - 2002
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2002.tb00828.x
Subject(s) - chondrite , meteorite , platinum group , ordinary chondrite , carbonaceous chondrite , geology , asteroid , group (periodic table) , geochemistry , mineralogy , platinum , astrobiology , chemistry , physics , organic chemistry , catalysis
— Platinum‐group element (PGE) concentrations and ratios obtained from samples of the Clearwater East impact melt have been used along with other siderophile element ratios to classify the impacting projectile as a carbonaceous chondrite. This is at odds with recent chromium isotope analyses that suggest ordinary chondrite‐type material is present. The present study reviews and reinterprets the available PGE data in the light of new PGE data from meteorites and concludes that the PGE ratios in the impact melt are most consistent with ordinary (possibly type‐L) chondrite source material, not carbonaceous chondrites. Therefore the structure was most probably formed by the impact of an asteroid composed of material similar to ordinary chondrites.