Fluid inclusion study of pegmatite and aplite veins of Palaeoproterozoic basement rocks in Bangladesh: Implications for magmatic fluid compositions and crystallization depth

• HOSSAIN Ismail

  Graduate School of Life and Environmental Sciences (Earth Evolution Sciences), University of Tsukuba Department of Geology and Mining, University of Rajshahi

• TSUNOGAE Toshiaki

  Graduate School of Life and Environmental Sciences (Earth Evolution Sciences), University of Tsukuba

抄録

We report the first fluid inclusion data on Palaeoproterozoic basement rocks in Bangladesh for the characterization of magmatic fluid compositions and determination of the crystallization pressure and temperature of the host rock. Fluid inclusions are present as primary and pseudosecondary types in quartz grains within pegmatite and aplite, which occur as veins in dioritic rocks. Both primary CO₂-rich and H₂O-rich inclusions are present, even in the same inclusion cluster, probably reflecting a single stage of fluid activity during the crystallization of the veins. The melting temperature (T_m) and homogenization temperature (T_h) of the dominant carbonic inclusions are in the ranges of −56.6 °C to −58.1 °C and −6.8 °C to +30 °C, respectively; the T_h values translate into densities of 0.59-0.97 g/cm³. Rare aqueous fluid inclusions have a final T_m value in the range of 0 °C to −10.8 °C and a T_h value in the range of +209.8 °C to +405.5 °C, which corresponds to bulk densities of 0.52-0.97 g/cm³. Isochores of the inclusions and temperatures obtained from the zircon saturation thermometry of pegmatite indicate that the veins crystallized at ∼ 4.8 kbar and 660-670 °C (depth of ∼ 14 km). The results of this study will be useful in understanding the magmatism and metallogeny of felsic igneous rocks of Bangladesh, which are related to the formation of the Columbia supercontinent.

収録刊行物

• Journal of Mineralogical and Petrological Sciences

  Journal of Mineralogical and Petrological Sciences 103 (2), 121-125, 2008

  一般社団法人　日本鉱物科学会

キーワード

• Fluid inclusion
• Pegmatite
• Aplite
• Zircon saturation thermometry
• Isochore
• Bangladesh

詳細情報

• CRID: 1390282681522445696
• NII論文ID: 10020737138
• NII書誌ID: AA11460926
• DOI: 10.2465/jmps.071022j
• 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