論文

査読有り
2017年6月

The occurrence of fluor-wagnerite in UHT granulites and its implications towards understanding fluid regimes in the evolution of deep crust: a case study from the Eastern Ghats Belt, India

MINERALOGY AND PETROLOGY
  • Kaushik Das
  • ,
  • Naotaka Tomioka
  • ,
  • Sankar Bose
  • ,
  • Jun-ichi Ando
  • ,
  • Ichiro Ohnishi

111
3
開始ページ
417
終了ページ
429
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1007/s00710-016-0474-y
出版者・発行元
SPRINGER WIEN

We report the occurrence of a rare phosphate mineral, fluor-wagnerite (Mg1.91-1.94Fe0.06-0.07Ca < 0.01) (P0.99-1.00O4)(OH0.02-0.17F0.98-0.83) from the Eastern Ghats Belt of India, an orogenic belt evolved during Meso- to Neoproterozoic time. The host rock, i.e. high- to ultrahigh temperature (UHT) granulites (similar to 1000 degrees C, 8-9 kbar) of the studied area was retrogressed after emplacement to mid-crustal level (800-850 degrees C, 6-6.5 kbar) as deduced from their pressure-temperature histories. Based on mineral chemical data and micro-Raman analyses, we document an unusual high Mg-F-rich chemistry of the F-wagnerite, which occur both in peak metamorphic porphyroblastic assemblages as well as in the retrograde matrix assemblage. Therefore, in absence of other common phosphates like apatite, fluor-wagnerite can act as an indicator for the presence of F-bearing fluids for rocks with high X (Mg) and/or fO(2). The occurrence of F-rich minerals as monitors for fluid compositions has important implications for the onset of biotite dehydration melting and hence melt production in the deep crust. We propose that fluor-wagnerite can occur as an accessory mineral associated with F-rich fluids in lower-mid crustal rocks, and F in coexisting minerals should be taken into consideration when reconciling the petrogenetic grid of biotite-dehydration melting.

Web of Science ® 被引用回数 : 3

リンク情報
DOI
https://doi.org/10.1007/s00710-016-0474-y
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000401789200009&DestApp=WOS_CPL

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