Title Origin of xenocrystic garnet and kyanite in clinopyroxene-hornblende-bearing adakitic meta-tonalites from Cape Hinode, Prince Olav Coast, East Antarctica
Author Hiroi, Y.; Motoyoshi, Y.; Ishikawa, N.; Hokada, T.; Shiraishi, K.
Author Affil Hiroi, Y., Chiba University, Department of Earth Sciences, Chiba, Japan. Other: National Institute of Polar Research, Japan; Kyushu University, Japan; Chiba University, Japan; National Institute of Polar Research, Japan; Kyoto University, Japan
Source Geodynamic evolution of East Antarctica; a key to the east-west Gondwana connection, edited by M. Satish-Kumar, Y. Motoyoshi, Y. Osanai, Y. Hiroi and K. Shiraishi. Geological Society Special Publications, Vol.308, p.333-350, . Publisher: Geological Society of London, London, United Kingdom. ISSN: 0305-8719. ISBN: 978-1-86239-268-7
Publication Date 2008
Notes In English. 61 refs. Ant. Acc. No: 85827
Index Terms Antarctica--East Antarctica; Antarctica--Prince Olav Coast; Antarctica; basalts; Cape Hinode; concentration; diorites; East Antarctica; electron probe data; garnet group; geochemistry; igneous rocks; International Polar Year 2007-08; IPY 2007-08 Research Publications; kyanite; Lutzow-Holm Complex; major elements; metaigneous rocks; metamorphic rocks; metamorphism; metatonalite; mid-ocean ridge basalts; mineral composition; nesosilicates; orthosilicates; P-T conditions; plutonic rocks; Precambrian; Prince Olav Coast; Proterozoic; Queen Maud Land; silicates; tonalite; trace elements; upper Precambrian; volcanic rocks; xenocrysts
Abstract 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 Lutzow-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 Lutzow-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.
URL http://hdl.handle.net/10.1144/SP308.16
Publication Type journal article
Record ID 290780