Indian Monsoonal Variations During the Past 80Kyr Recorded in NGHP-02 Hole 19B, Western Bay of Bengal: Implications From Chemical and Mineral Properties

Autor: Yohei Hamada, Masataka Kinoshita, Hodaka Kawahata, Nobuharu Komai, Shun Nomura, Sean Toczko, Lallan P. Gupta, Kan Aoike, Takamitsu Sugihara, Natsue Abe, Keita Umetsu, Kyaw Moe, Hung Yu Wu, Hisami Suga, Lena Maeda, Toshiya Kanamatsu, Wataru Tanikawa, Yuichi Shinmoto, Junichiro Kuroda, Yuki Ota, Yuka Masaki, Weiren Lin, Takehiro Hirose, Maria Luisa G. Tejada, Asuka Yamaguchi, Ayako Abe-Ouchi, Saneatsu Saito, Naokazu Ahagon, Shuro Yoshikawa, Yasuyuki Nakamura, Hideaki Machiyama, Akira Ijiri, Daisuke Araoka, Atsushi Suzuki, Yasuhiro Yamada, Yoshinori Sanada, Yoichi Usui, Yuzuru Yamamoto, Francisco J. Jiménez-Espejo, Satoru Haraguchi, Yusuke Kubo, Koichi Iijima
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Geochemistry, Geophysics, Geosystems. 20(1):148-165
ISSN: 1525-2027
Popis: 金沢大学理工研究域地球社会基盤学系
Detailed reconstruction of Indian summer monsoons is necessary to better understand the late Quaternary climate history of the Bay of Bengal and Indian peninsula. We established a chronostratigraphy for a sediment core from Hole 19B in the western Bay of Bengal, extending to approximately 80kyr BP and examined major and trace element compositions and clay mineral components of the sediments. Higher δ 18 O values, lower TiO 2 contents, and weaker weathering in the sediment source area during marine isotope stages (MIS) 2 and 4 compared to MIS 1, 3, and 5 are explained by increased Indian summer monsoonal precipitation and river discharge around the western Bay of Bengal. Clay mineral and chemical components indicate a felsic sediment source, suggesting the Precambrian gneissic complex of the eastern Indian peninsula as the dominant sediment source at this site since 80kyr. Trace element ratios (Cr/Th, Th/Sc, Th/Co, La/Cr, and Eu/Eu*) indicate increased sediment contributions from mafic rocks during MIS 2 and 4. We interpret these results as reflecting the changing influences of the eastern and western branches of the Indian summer monsoon and a greater decrease in rainfall in the eastern and northeastern parts of the Indian peninsula than in the western part during MIS 2 and 4. © 2018. American Geophysical Union. All Rights Reserved.
Databáze: OpenAIRE