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On the thermal history of heavily shocked Yanzhuang H‐chondrite
Author(s) -
Begemann F.,
Palme H.,
Spettel B.,
Weber H. W.
Publication year - 1992
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1992.tb00745.x
Subject(s) - radiogenic nuclide , parent body , meteorite , meteoroid , chondrite , geology , geochemistry , diffusion , thermal shock , mineralogy , materials science , thermodynamics , mantle (geology) , astrobiology , metallurgy , physics
Partly shock‐melted Yanzhuang H‐chondrite, now classified as petrological type H6 but before the shock event of type H4, was subjected to the shock‐heating 2.6 Ma ago at the time it was spalled off its parent body and came into being as a meteoroid of ca . 30 cm radius. At that time the un melted portion of the meteoroid suffered an almost complete loss of its radiogenic 4 He and 40 Ar while the contents of the most volatile non‐noble gas elements Zn and Se were not measurably affected. The melted portion of Yanzhuang is also essentially void of radiogenic 4 He (10 ± 4 × 10 −8 cm 3 STP/g) but it has retained some 80% of its radiogenic 40 Ar, presumably because in the melt the increase of the diffusion length more than compensated the increase of the diffusion constant.