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NOBLE GASES IN THE UNIQUE CHONDRITE, KAKANGARI
Author(s) -
Srinivasan B.,
Anders Edward
Publication year - 1977
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1977.tb00460.x
Subject(s) - chondrite , enstatite , regolith , parent body , geology , ordinary chondrite , astrobiology , meteorite , noble gas , chondrule , geochemistry , mineral , carbonaceous chondrite , mineralogy , chemistry , physics , organic chemistry
The Kakangari chondrite has a cosmic‐ray exposure age of 5.4 m.y. and a K‐Ar age near 4 g.y. Its high cosmogenic 3 He/ 21 Ne ratio of 7.5 indicates a small preatmospheric mass. The He and Ne are largely of solar‐wind origin, presumably implanted during exposure in the regolith of its parent body. The heavy gases Ar, Kr, Xe are largely of planetary origin. Taken together, the low 129 Xe/ 132 Xe (1.07), low 36 Ar/ 132 Xe (225), and high 132 Xe content (45 × 10 −10 cc STP/g) are more similar to the values for unequilibrated ordinary chondrites or even C1, C2 chondrites than to enstatite chondrites, and suggest that Kakangari has the same gas‐bearing mineral assemblage as the former, in spite of its high degree of reduction (Fa 4.9 ).