The Tenth Symposium on Polar Science/Ordinary sessions: [OG] Polar Geosciences, Wed. 4 Dec. / Entrance Hall (1st floor), National Institute of Polar Researc

Atsushi Kamei

Ippei Kitano

Kenji Horie

Mami Takehara

Sotaro Baba

Tomokazu Hokada

Yoichi Motoyoshi

Yoshikuni Hiroi

National Institute of Polar Research Repository

  Geologic connection between Dronning Maud Land and Enderby Land  Tomokazu Hokada1,2, Kenji Horie1,2, Sotaro Baba3, Atsushi Kamei4, Ippei Kitano5, Yoichi Motoyoshi1,2, Yoshikuni Hiroi1,6, Mami Takehara1 and Kazuyuki Shiraishi1 1National Institute of Polar Research 2The Graduate University for Advanced Studies, SOKENDAI 3University of the Ryukyus 4Shimane University 5Kyushu University 6Chiba University  East Antarctic Shield is one of essential pieces of the Gondwana supercontinent. Three spatially and temporally discrete Grenville-age (late Mesoproterozoic to early Neoproterozoic) crustal segments, the Maud, Rayner and Wilkes Provinces, comprise the pre-Gondwana fragments of East Antarctica, and these three provinces were juxtaposed along Pan African-age (late Neoproterozoic to Cambrian) mobile belts (Fitzsimons, 2000a, 200b). In Enderby Land, two distinct Proterozoic-Cambrian metamorphic terranes, the Rayner and the Western Rayner Complexes (e.g., Shiraishi et al., 2008) bound the southern margin of the Archaean-Paleoproterozoic Napier Complex. The Rayner Complex is characterized by >2500-1000 Ma protolith and 980-910 Ma granulite-facies metamorphic ages (e.g., Kelly et al., 2002). The Western Rayner Complex is granulite-facies and partly UHT metamorphism (Motoyoshi et al., 1994, 1995) and 2400-1000 Ma protolith and 540-520 Ma metamorphic ages were reported (Shiraishi et al., 1997). The boundary between the Rayner and the Western Rayner Complex has been not clearly defined until when Horie et al. (2016) obtained 934-894 Ma SHIRMP zircon U-Pb ages from Mt. Lira, Condon Hills and Mt. Yuzhnaya regions with minor 590-570 Ma zircons from Mt. Yuzhnaya. Hiroi (unpublished data) also demonstrated contrasting metamorphic P-T evolution among the Mt. Lira, Condon Hills and Mt. Yuzhnaya regions. Recent Japanese Antarctic program made short visits and sampling at several small nunataks in the Rayner and the Western Rayner Complexes boundary zones. We will report and discuss the update of the characteristic features of the Rayner and the Western Rayner Complexes, that are of the implications for Dronning Maud Land –Enderby Land connection.  References Fitzsimons, I.C.W., 2000. A review of tectonic events in the East Antarctic Shield and their implications for Gondwana and earlier supercontinents. Journal of African Earth Science, 31, 2–23. Fitzsimons, I.C.W. 2000. Grenville-age basement provinces in East Antarctica; evidence for three separate collisional orogens. Geology, 28, 879–882. Horie, K., Hokada, T., Motoyoshi, Y., Shiraishi, K., Hiroi, Y., Takehara, M., 2016. U-Pb zircon geochronology in the western part of the Rayner Complex, East Antarctica. Journal of Mineralogical and Petrological Sciences, 111, 104-117. Kelly, N.M., Clarke, G.L., Fanning, C.M., 2002. A two-stage evolution of the Neoproterozoic Rayner Structural Episode: new U–Pb sensitive high resolution ion microprobe constraints from the Oygarden Group, Kemp Land, East Antarctica. Precambrian Research, 116, 307-330.   Motoyoshi, Y., Ishikawa, M., Fraser, G.L., 1994. Reaction textures in granulites from Forefinger Point, Enderby Land, East Antarctica: an alternative interporetation on the metamorphic evolution of the Rayner Complex. Proceedings of the NIPR Symposium on Antarctic Geosciences, 7, 191-114.   Motoyoshi, Y., Ishikawa, M., Fraser, G.L., 1995. Sapphirine-bearing silica-undersaturated granulites from Forefinger Point, Enderby Land, East Antarctica: evidence for a clockwise P-T path?. Proceedings of the NIPR Symposium on Antarctic Geosciences, 8, 121-129.  Shiraishi, K., Ellis, D.J., Fanning, C.M., Hiroi, Y., Kagami, H., Motoyoshi, Y., 1997. Reexamination of the metamorphic and protolith ages of the Rayner complex, Antarctica: Evidence for the Cambrian (Pan-African) regional metamorphic event. In: Ricci, C. A. (Ed.) The Antarctic Region: Geological Evolution and Processes. Terra Antartica, Sienna, 79–88.  Shiraishi, K., Dunkley, D.J., Hokada, T., Fanning, C.M., Kagami, H. and Hamamoto, T., 2008.  Geochronological constraints on the Late Proterozoic to Cambrian crustal evolution of eastern Dronning Maud Land, East Antarctica: a synthesis of SHRIMP U-Pb age and Nd model age data.  In: Geodynamic evolution of East Antarctica: a Key to the East-West Gondwana Connection, eds by M. Satish-Kumar et al., Geological Society of London Special Publications, 308, 21-67. 

Geologic connection between Dronning Maud Land and Enderby Land

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Geologic connection between Dronning Maud Land and Enderby Land

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