Carbonic fluid inclusions in amphibolite-facies pelitic schists from Bodonch area, western Mongolian Altai

• ZORIGTKHUU Oyun-Erdene

  Graduate School of Life and Environmental Sciences, University of Tsukuba School of Geology and Petroleum Engineering, Mongolian University of Science and Technology

• TSUNOGAE Toshiaki

  Graduate School of Life and Environmental Sciences, University of Tsukuba Department of Geology, University of Johannesburg

• DASH Batulzii

  School of Geology and Petroleum Engineering, Mongolian University of Science and Technology

Abstract

We report first fluid inclusion data on amphibolite-facies pelitic schists from Bodonch area of western Mongolian Altai in the Central Asian Orogenic Belt. Three categories of fluid inclusions have been observed in quartz: dominant primary and secondary inclusions, and least dominant pseudosecondary inclusions. The melting temperatures of all the categories of inclusions lie in the narrow range of -57.5 °C to -56.6 °C, close to the triple point of pure CO₂. Homogenization of fluids occurs into liquid phase at temperature between -33.3 °C to +19.4 °C, which convert into densities in the range of 0.78 g/cm³ to 1.09 g/cm³. The estimated CO₂ isochores for primary and pseudosecondary high-density inclusions is broadly consistent with the peak metamorphic condition of the studied area (6.3-7.3 kbar at 655 °C). The results of this study, together with the primary and pseudosecondary nature of the inclusions, indicate CO₂ was the dominant fluid component during the peak amphibolite-facies metamorphism of the study area. The examined quartz grains are texturally associated with biotite, kyanite and staurolite, which are regarded as high-grade minerals formed during prograde to peak metamorphism. Therefore quartz probably formed by high-grade metamorphism and the primary fluid inclusions trapped in the minerals probably preserve fluids at around peak metamorphism.

Journal

• Journal of Mineralogical and Petrological Sciences

  Journal of Mineralogical and Petrological Sciences 107 (1), 44-49, 2012

  Japan Association of Mineralogical Sciences

Keywords

• Fluid inclusion
• Microthermometry
• CO₂
• Altai Orogeny
• Central Asian Orogenic Belt
• Mongolia

Details

• CRID: 1390282681521509760
• NII Article ID: 10030122231
• NII Book ID: AA11460926
• DOI: 10.2465/jmps.111020e
• BIBCODE: 2012JMPeS.107...44Z
• COI: 1:CAS:528:DC%2BC38XmtlGktbs%3D
• ISSN: 13493825
• ISSN: 13456296
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed