Primordial and cosmogenic noble gases in the Sutter's Mill CM chondrite

Ryuji Okazaki, Keisuke Nagao

研究成果: Contribution to journalArticle査読

4 被引用数 (Scopus)


The Sutter's Mill (SM) CM chondrite fell in California in 2012. The CM chondrite group is one of the most primitive, consisting of unequilibrated minerals, but some of them have experienced complex processes occurring on their parent body, such as aqueous alteration, thermal metamorphism, brecciation, and solar wind implantation. We have determined noble gas concentrations and isotopic compositions for SM samples using a stepped heating gas extraction method, in addition to mineralogical observation of the specimens. The primordial noble gas abundances, especially the P3 component trapped in presolar diamonds, confirm the classification of SM as a CM chondrite. The mineralogical features of SM indicate that it experienced mild thermal alteration after aqueous alteration. The heating temperature is estimated to be <350 °C based on the release profile of primordial 36Ar. The presence of a Ni-rich Fe-Ni metal suggests that a minor part of SM has experienced heating at >500 °C. The variation in the heating temperature of thermal alteration is consistent with the texture as a breccia. The heterogeneous distribution of solar wind noble gases is also consistent with it. The cosmic-ray exposure (CRE) age for SM is calculated to be 0.059 ± 0.023 Myr based on cosmogenic 21Ne by considering trapped noble gases as solar wind, the terrestrial atmosphere, P1 (or Q), P3, A2, and G components. The CRE age lies at the shorter end of the CRE age distribution of the CM chondrite group.

ジャーナルMeteoritics and Planetary Science
出版ステータス出版済み - 4 2017

All Science Journal Classification (ASJC) codes

  • 地球物理学
  • 宇宙惑星科学


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