Experimental synthesis of isochemical kelyphite — a preliminary report

• OBATA Masaaki

  Graduate School of Science, Kyoto University

• OHI Shugo

  Department of Geology and Mineralogy, Graduate School of Science, Kyoto University

• MIYAKE Akira

  Department of Geology and Mineralogy, Graduate School of Science, Kyoto University

Abstract

We observed the breakdown of natural garnet in a high–pressure experiment (0.85 GPa and 1100 °C for 2 days) using a piston–cylinder apparatus. Two different types of kelyphites were formed: (1) isochemical and (2) metasomatic. The isochemical kelyphite was composed of orthopyroxene + spinel + plagioclase, whereas the metasomatic one, having a composition altered significantly from the original garnet, was composed of olivine + spinel + plagioclase. These synthetic kelyphites were studied and characterized using EPMA, SEM, EBSD, and TEM and were shown to have many microstructural features as well as their mineral assemblages in common with observed natural kelyphites. The kelyphitization was very heterogeneous and local and was apparently controlled by grain surfaces and intra–grain cracks in garnet. The metasomatic kelyphite apparently formed by a reaction between garnet and aqueous fluids that may have been introduced from outside the platinum capsule through holes accidentally made in the capsule.

Journal

• Journal of Mineralogical and Petrological Sciences

  Journal of Mineralogical and Petrological Sciences 109 (2), 91-96, 2014

  Japan Association of Mineralogical Sciences

Keywords

• Symplectite
• Kelyphite
• Breakdown of garnet
• High–pressure experiment
• TEM

Details

• CRID: 1390001206547036800
• NII Article ID: 130003392377
• DOI: 10.2465/jmps.131022a
• ISSN: 13493825
• ISSN: 13456296
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed