日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 S (固体地球科学) » S-MP 岩石学・鉱物学

[S-MP31] Supercontinents and Crustal Evolution

2019年5月28日(火) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:Satish-Kumar Madhusoodhan(Department of Geology, Faculty of Science, Niigata University)、外田 智千(国立極地研究所)、Sajeev Krishnan(Centre for Earth Sciences, Indian Institute of Science)、小山内 康人(九州大学大学院比較社会文化研究院地球変動講座)

[SMP31-P01] Re-examination of metamorphic and geochronologic events in Rayner Complex and Western Rayner Complex in Antarctica

*外田 智千1,2馬場 壮太郎3亀井 淳志4北野 一平5堀江 憲路1,2廣井 美邦1,6本吉 洋一1,2竹原 真美1白石 和行1 (1.国立極地研究所、2.総合研究大学院大学、3.琉球大学、4.島根大学、5.九州大学、6.千葉大学)

キーワード:南極、ゴンドワナ、超大陸、変成作用、地質年代

Enderby Land in Antarctica comprises of Neoproterozoic-Cambrian (c.650-500 Ma) high-grade metamorphic terranes that constituting Gondwana supercontinent (e.g., Shiraishi et al., 2008). Easternmost part is “Western Rayner Complex” of which 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). Neighboring “Rayner Complex” is characterized by >2500-1000 Ma protolith and 980-910 Ma granulite-facies metamorphic ages. 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 Hiroi (unpublished data) also demonstrated contrasting metamorphic P-T evolution among the Mt.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.

JARE-58 (2016-2017) geology team made a short visit and sampling at a small nunatak of west of Mt. Yuzhnaya, a small nunatak of east of Forefinger Point, and Point Widdows in order to assess the relationship between the Rayner and the Western Rayner Complexes. We will report and discuss the update of the characteristic features of the Rayner and the Western Rayner Complexes.