Sr-sulphate and associated minerals found from kyanite-bearing eclogite in the Moldanubian Zone of the Bohemian Massif, Czech Republic

• NAKAMURA Daisuke

  Department of Earth Sciences, Faculty of Science, Okayama University

• KOBAYASHI Tomoyuki

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

• SHIMOBAYASHI Norimasa

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

• SVOJTKA Martin

  Institute of Geology, Academy of Sciences of the Czech Republic v.v.i

• HIRAJIMA Takao

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

抄録

Sr-sulphate, celestine, was newly found in a kyanite-bearing eclogite associated with the Nové Dvory peridotite mass in the Moldanubian Zone of the Bohemian Massif, Czech Republic. Celestine is closely associated with anhydrite, pyrite, pyrrhotite and chalcopyrite, and those minerals occur in the matrix, where fine-grained omphacite aggregate and kelyphites after garnet develop. A common Sr reservoir in eclogite is known to be epidote, but the maximum pressure-temperature (P-T) conditions of the studied eclogite was estimated as about 1050-1150 °C, 4.5-4.9 GPa. In such extremely high P-T conditions, epidote should be unstable. In fact, epidote is absent from most of eclogites in the Moldanubian Zone of Czech Republic. These facts suggest that a Sr-reservoir after the epidote-breakdown in subducting eclogite might be celestine, or its high-P polymorph, although the formation stage of celestine in the study sample and maximum stability limits of celestine are not known. Another idea is that celestine in the study sample was formed at relatively shallow levels after the ascent of the eclogite. In this case, omphacite and apatite would have contained significant amount of Sr under the eclogite-facies conditions. Otherwise, metasomatic infiltration of Sr-rich fluids into the eclogite is necessary for the formation of celestine in order to provide sufficient amount of Sr. A Ba-rich alumino-silicate, probably celsian, was also found as a retrograde product around pyrrhotite in kelyphite and in symplectites mainly composed of augite and plagioclase after omphacite. Several grains of biotite are also present along the margin of garnet and in the symplectites after omphacite. In addition, small amounts of muscovite and amphibole are present in the symplectites after omphacite. These findings suggest that metasomatism with Sr- and Ba-rich fluids may have occurred during decompression of the eclogite and may not be indicative of the UHP history of these rocks.

収録刊行物

• Journal of Mineralogical and Petrological Sciences

  Journal of Mineralogical and Petrological Sciences 105 (5), 251-261, 2010

  一般社団法人　日本鉱物科学会

キーワード

• Celestine
• Sr
• Eclogite
• Sulphide
• Bohemian Massif

詳細情報

• CRID: 1390282681522324608
• NII論文ID: 10027123250
• NII書誌ID: AA11460926
• DOI: 10.2465/jmps.090817
• ISSN: 13493825
• ISSN: 13456296
• 本文言語コード: en
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可