Carbonic fluid inclusions in ultrahigh-temperature granulite from Kumiloothu in the northern Madurai Block, southern India

• OHYAMA Hiroyuki

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

• TSUNOGAE Toshiaki

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

• SANTOSH M.

  Department of Natural Environmental Science, Faculty of Science, Kochi University

Abstract

We report fluid inclusion data on ultrahigh-temperature (UHT) granulites from Kumiloothu in the northern Madurai Block situated along the Palghat-Cauvery Shear Zone system in southern India. Three categories of fluid inclusions have been observed: primary inclusions in garnet comprising the dominant category, secondary inclusions in garnet, and rare primary inclusions in rutile and apatite enclosed within garnet. The melting temperatures of all the categories of inclusions lie in the narrow range of −57.0 to −56.6 °C, close to the triple point of pure CO₂. Most of the fluid inclusions homogenize into the liquid phase between a temperature range of +11.3 to +30.3 °C, corresponding to low-CO₂ densities of 0.59-0.85 g/cm³. Slightly higher density of 0.95 g/cm³ was obtained from a primary inclusion in rutile that homogenized at −3.6 °C. The fluid densities, when computed into isochores, indicate lower pressures (∼ 6.6 kbar at 1000 °C) than the peak P-T conditions (T >1000 °C at ∼ 8 kbar) estimated for this region. The results of this study, together with the primary nature of the inclusions trapped in high-grade minerals, indicates density reversal of peak metamorphic fluid, a common feature for many UHT granulites along the Gondwana suture zone as well as other UHT terranes showing clockwise P-T history.

Journal

• Journal of Mineralogical and Petrological Sciences

  Journal of Mineralogical and Petrological Sciences 103 (4), 273-278, 2008

  Japan Association of Mineralogical Sciences

Keywords

• Carbonic fluid inclusion
• Ultrahigh-temperature granulite
• Madurai Block
• Palghat-Cauvery Shear Zone System
• Gondwana suture
• Southern India

Details

• CRID: 1390001206546803712
• NII Article ID: 10021369956
• NII Book ID: AA11460926
• DOI: 10.2465/jmps.080116b
• ISSN: 13493825
• ISSN: 13456296
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed