Thursday, 30 August 2007 - 3:40 PM
4.P2.C-1
Metamorphic evolution of UHT calc-silicate rocks from Rundvågshetta, Lützow Holm Bay, East Antarctica
M. Satish-Kumar1, Y. Motoyoshi2, and D. J. Dunkley2. (1) Institute of Geoscience, Shizuoka University, Oya 836-1, Suruga-ku, Shizuoka, 422-8529, Japan, (2) National Institute of Polar Research, Kaga, Itabashi-ku, Tokyo, 173-8515, Japan
Calc-silicate boudins within the pyroxene gneiss at Rundvågashetta, Lützow-Holm Bay, East Antarctica preserve petrologic signatures of ultra-high temperature metamorphism and microstructures that gave insights to the regional metamorphic evolution. Three mineralogical zones of varying modal proportion of an assemblage of grandite-garnet + scapolite + clinopyroxene + plagioclase + titanite +/- wollastonite +/- calcite +/- quartz are observed. Meionitic scapolite coexists with anorthite suggesting a minimum peak metamorphic temperature of ~830ºC. Several generations of chemically distinct garnet corona and breakdown reactions involving garnet, scapolite clinopyroxene and wollastonite are observed. Activity corrected partial petrogentic grids, constructed in the CAFSV system, helped in constraining the P-T-X-fO2 evolution during peak and retrograde metamorphism. These results were then supplemented with titanite SHRIMP geochronology to consider the exhumation history of the region. Taking into account of the existing models on P-T-t evolution, a geodynamic evolution of the Rundvågshetta granulites within the Lützow-Holm Complex was formulated.
See more of Evolution of antarctic lithosphere ORAL
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See more of The 10th International Symposium on Antarctic Earth Sciences (Aug. 26 to Sept 1, 2007)
See more of General Submissions
See more of The 10th International Symposium on Antarctic Earth Sciences (Aug. 26 to Sept 1, 2007)