Weakening of the South Asian summer monsoon linked to interhemispheric ice-sheet growth since 12 Ma

Zhengquan Yao; Xuefa Shi; Zhengtang Guo; Xinzhou Li; B Nagender Nath; Christian Betzler; Hui Zhang; Sebastian Lindhorst; Pavan Miriyala

doi:10.1038/s41467-023-36537-6

Weakening of the South Asian summer monsoon linked to interhemispheric ice-sheet growth since 12 Ma

Nat Commun. 2023 Feb 14;14(1):829. doi: 10.1038/s41467-023-36537-6.

Authors

Zhengquan Yao^{1

2}, Xuefa Shi^{3

4}, Zhengtang Guo^{5

6

7}, Xinzhou Li^{8

9}, B Nagender Nath¹⁰, Christian Betzler¹¹, Hui Zhang^{12

13}, Sebastian Lindhorst¹¹, Pavan Miriyala¹⁴

Affiliations

¹ Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China. yaozq@fio.org.cn.
² Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China. yaozq@fio.org.cn.
³ Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China. xfshi@fio.org.cn.
⁴ Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China. xfshi@fio.org.cn.
⁵ Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.
⁶ CAS Center for Excellence in Life and Paleoenvironment, Beijing, China.
⁷ University of Chinese Academy of Sciences, Beijing, China.
⁸ State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
⁹ CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, China.
¹⁰ Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa, India.
¹¹ Institute of Geology, CEN, University of Hamburg, Hamburg, Germany.
¹² Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China.
¹³ Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
¹⁴ CSIR-National Geophysical Research Institute, Hyderabad, India.

Abstract

The evolution and driving mechanism of the South Asian summer monsoon (SASM) are still poorly understood. We here present a 12-Myr long SASM record by analyzing the strontium and neodymium isotopic composition of detrital components at IODP Exp. 359 Site U1467 from the northern Indian Ocean. The provenance investigation demonstrates that more dust enriched in εNd from northeastern Africa and the Arabian Peninsula was transported to the study site by monsoonal and Shamal winds during the summer monsoon season. A two-step weakening of the SASM wind since ~12 Ma is proposed based on the εNd record. This observational phenomenon is supported by climate modeling results, demonstrating that the SASM evolution was mainly controlled by variations in the gradient between the Mascarene High and the Indian Low, associated with meridional shifts of the Hadley Cell and the Intertropical Convergence Zone, which were caused by interhemispheric ice-sheet growth since the Middle Miocene.