Origin of xenocrystic garnet and kyanite in clinopyroxene–hornblende-bearing adakitic meta-tonalites from Cape Hinode, Prince Olav Coast, East Antarctica
Yoshikuni Hiroi, Yoichi Motoyoshi, Naoto Ishikawa, Tomokazu Hokada, Kazuyuki Shiraishi, 2008. "Origin of xenocrystic garnet and kyanite in clinopyroxene–hornblende-bearing adakitic meta-tonalites from Cape Hinode, Prince Olav Coast, East Antarctica", Geodynamic Evolution of East Antarctica: A Key to the East–West Gondwana Connection, M. Satish-Kumar, Y. Motoyoshi, Y. Osanai, Y. Hiroi, K. Shiraishi
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Xenocrystic garnet and kyanite, in addition to clinopyroxene and rare orthopyroxene, are newly found to occur in middle Proterozoic slightly metamorphosed adakitic trondhjemites and tonalites (meta-tonalites) at Cape Hinode on the eastern Prince Olav Coast in the latest Proterozoic–Early Palaeozoic Lützow-Holm Complex, East Antarctica. Textural and compositional features of garnet and kyanite suggest that these minerals formed most probably as restite phases of partial melting of mid-ocean ridge basalt (MORB) between 15 and 20 kbar pressure, and were entrained by the tonalitic magmas, which underwent fractional crystallization upon ascent to form cumulates that were also entrained and metamorphosed to basic–intermediate granulite blocks. Available geochronological data for the meta-tonalites indicate that all these events including MORB formation took place in the middle Proterozoic. The meta-tonalites and associated basic, calc-silicate, and pelitic rocks were emplaced as an allochthonous block in the Lützow-Holm Complex at the waning stage of its main regional metamorphism, most probably as a part of the final amalgamation of East and West Gondwana into the Gondwana supercontinent.
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Geodynamic Evolution of East Antarctica: A Key to the East–West Gondwana Connection
Geological correlations of East Antarctica with adjoining continents have been puzzling geologists ever since the concept of a Gondwana supercontinent surfaced. Despite the paucity of outcrops because of ice cover, difficulty of access and extreme weather, the past 50 years of Japanese Antarctic Research Expeditions (JARE) has successfully revealed vital elements of the geology of East Antarctica. This volume presents reviews and new research from localities across East Antarctica, especially from Dronning Maud Land to Enderby Land, where the geological record preserves a history that spans the Archaean and Proterozoic. The reviews include extensive bibliographies of results obtained by geologists who participated in the JARE. Comprehensive geological, petrological and geochemical studies, form a platform for future research on the formation and dispersion of Rodinia in the Mesoproterozoic and subsequent assembly of Gondwana in the Neoproterozoic to Early Palaeozoic.