Carbonic fluid inclusions in sapphirine + quartz bearing garnet granulite from the Limpopo Belt, southern Africa

• TSUNOGAE Toshiaki

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

• VAN REENEN Dirk D.

  Department of Geology, University of Johannesburg

Abstract

Sapphirine + quartz bearing garnet granulite from the Central Zone of the Neoarchean Limpopo Belt contains three categories of fluid inclusions: dominant pseudosecondary inclusions in garnet and plagioclase, secondary inclusions in matrix quartz, and least dominant primary inclusions in the same quartz grains. The melting temperatures of the trapped fluids lie in the range of −58.6 to −56.4 °C. Homogenization of the pseudosecondary inclusions into the liquid phase occurs within the temperature range of +9.1 to +28.4, which correspond to CO₂ densities of 0.72 to 0.87 g/cm³. In contrast, primary inclusions homogenized at +6.1 ±</i> 3.1 °C, which translates into slightly higher densities of 0.87-0.91 g/cm³. The fluid densities, when computed into isochores, indicate entrapment of CO₂ at lower pressure than the peak P-T condition of the rock. The results imply either influx of CO₂-rich fluids during post-peak uplift or density reversal of peak metamorphic carbonic fluid. Lack of aqueous fluid inclusions and abundant pseudosecondary carbonic inclusions in the rock confirmed that low-H₂O activity condition is necessary to form unique sapphirine + quartz assemblage.

Journal

• Journal of Mineralogical and Petrological Sciences

  Journal of Mineralogical and Petrological Sciences 102 (1), 57-60, 2007

  Japan Association of Mineralogical Sciences

Keywords

• Carbonic fluid inclusion
• Sapphirine + quartz
• Granulite
• Limpopo Belt
• Southern Africa

Details

• CRID: 1390001206544846464
• NII Article ID: 10018411553
• NII Book ID: AA11460926
• DOI: 10.2465/jmps.060829
• ISSN: 13493825
• ISSN: 13456296
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed