Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

S (Solid Earth Sciences) » S-MP Mineralogy & Petrology

[S-MP35] Antarctica and surrounds in Supercontinent Evolution

Tue. May 22, 2018 9:00 AM - 10:30 AM 302 (3F International Conference Hall, Makuhari Messe)

convener:Tomokazu Hokada(National Institute of Polar Research), Yasuhito Osanai(Division of Evolution of Earth Environments, Faculty of Social and Cultural Studies, Kyushu University), Geoffrey Hugo Grantham (共同), Madhusoodhan Satish-Kumar(Department of Geology, Faculty of Science, Niigata University), Chairperson:Satish-Kumar Madhusoodhan(Niigata University), Kitano Ippei(Kyushu University)

9:00 AM - 9:15 AM

[SMP35-01] Re-examination of metamorphic and geochronologic events in eastern Dronning Maud Land and Enderby Land, East Antarctica: current status and future perspectives

*Tomokazu Hokada1,2, Sotaro Baba3, Atsushi Kamei4, Ippei Kitano5, Prayath Nantasin6, Nugroho Setiawan7, Davaa-ochir Dashbaatar8, Yoichi Motoyoshi1,2, Yoshikuni Hiroi1, Yasuhito Osanai5, Daniel Dunkley, Kenji Horie1,2, Mami Takehara1, Kazuyuki Shiraishi1 (1.National Institute of Polar Research, 2.The Graduate University for Advanced Studies (SOKENDAI), 3.University of the Ryukyus, 4.Shimane University, 5.Kyushu University, 6.Kasetsart University, 7.Gadjah Mada University, 8.Mongolian University of Science and Technology)

Keywords:Antarctica, Gondwana, supercontinent, metamorphism, geochronology

Eastern part of Dronning Maud Land in East Antarctica comprises of the multiple high-grade metamorphic terranes as major constituents of Gondwana supercontinent. The Lützow-Holm Complex in eastern Dronning Maud Land has been belived to be typical of continental collision metamorphic belt of which amphibolite to granulite (partly UHT) facies regional metamorphism and clockwise P-T trajectory supported by the widespread occurrence of sillimanite with prograde kyanite and retrograde andalusite (e.g., Hiroi et al., 1983). However, it requires re-evaluation of the metamrophic processes by recent finding of nanogranite/felsite inclusions (Hiroi et al., 2014) and unusual occurrence of kyanite and andalusite. Major 550-520 Ma metamorphic age episode was indicated by SHRIMP zircon geochronology (e.g., Shiraishi et al., 1992; 1994; 2003) and was recently refined the early metamorphic events at >600 Ma (Hokada and Motoyoshi, 2006; Dunkley et al., 2014).

Archaean and Proterozoic pre-Gondwana history is preserved in the Napier Complex and the Rayner Complex in Enderby Land with the earliest geologic history traced back to >3.8 Ga (e.g., Harley and Kelly, 2007). Western Rayner Complex located between Lützow-Holm Complex and Napier-Rayner Complexes is key for the linkage between Gondwana and pre-Gondwana areas. All these areas were experienced granulite-facies partly UHT metamorphism.

This study will present our current understainding of the metamorphic and geochronologic evolution of these areas and the recent geologic field survey at Lützow-Holm, Western Rayner, Rayner and Napier Complexes during 2016-2017, and also future perspectives.