Mineralogy of Antarctic aubrites, Yamato-793592 and Allan Hills-78113: Comparison with non-Antarctic aubrites and E-chondrites

• KIMURA M.

  Department of Earth Science, Faculty of Science, Ibaraki University

• Lin Yang-Ting

  Institute of Geochemistory, Academica Sinica

• Ikeda Yukio

  Department of Earth Science, Faculty of Science, Ibaraki University

• Goresy Ahmed EL

  Max-Planck Institute fur Kernphysik

• Yanai Keizo

  National Institute of Polar Research

• Kojima Hideyasu

  National Institute of Polar Research

抄録

Two Antarctic aubrites, Yamato (Y)-793592 and Allan Hills (ALH)-78113,were mineralogically studied, for comparison with minerals in non-Antarctic aubrites and enstatite chondrites. The Antarctic aubrites are breccias consisting of coarse-grained enstatite fragments and fine-grained matrix. ALH-78113 has 200-300μm dark clasts that are fine-grained aggregates of silicate and opaque minerals. FeO-rich pyroxene (up to Fs_<21>) occurs in the dark clasts. One dark clast has K-feldspar. These dark clasts seem to be exotic inclusions with distinct mineralogy. Daubreelite in the two Antarctic and non-Antarctic aubrites is lower in Zn than those in EH3-5 chondrites. This reflects the depletion of volatile elements in aubrites. Hydrated Na-Cr-sulfides were also found. Djerfisherite is a common accessory mineral in aubrites. It is characterized by low contents of Cu and Na, and high content of Ni, in comparison to djerfisherite in EH3-5 chondrites. Y-793592 has many roedderite grains. The occurrences of roedderite, Na-Cr-sulfides and djerfisherite in aubrites suggest that Al_2O_3 relative to alkali elements may have been fractionated during nebular or magmatic process.

収録刊行物

• Proc. NIPR Symp. Antarc. Meteorites

  Proc. NIPR Symp. Antarc. Meteorites 6 186-203, 1993

  国立極地研究所

詳細情報

• CRID: 1570572701820021632
• NII論文ID: 110000029977
• NII書誌ID: AA10784627
• ISSN: 09145621
• 本文言語コード: en
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