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Investigating Sea-Level Sediment Transport And The Summer Monsoon Season | Science Trends

Investigating Sea-Level Sediment Transport And The Summer Monsoon Season

The International Ocean Discovery Program (IODP) is one of the most an influential marine research collaboration programs that explores the Earth’s history and dynamics using ocean-going research platforms to recover data recorded in seafloor sediments and rocks and to monitor sub-seafloor environments. The IODP Expedition 355 (Arabian Sea Monsoon) started in Colombo, Sri Lanka, from March 31 to May 30, 2015, aiming to better understand the co-evolution of the Tibetan plateau uplift, Indian summer monsoon evolution, weathering, and erosion of Himalaya through multiple time scales.

Long-term marine sediment archives deposited in the deep-sea fan are key materials to study the sensitivity of sediment dynamics in responding to monsoon precipitation evolution and sea-level variations. Previous studies suggest that both Indian summer monsoon precipitation and sea-level are playing important roles in determining the sediment transportation from the large river basin to the deep-sea fan in the Asia area.

On the orbital timescale, both the spectra of East Asian summer monsoons and sea level proxies indicate dominant 100-kyr eccentricity bands during the Late Quaternary in the East Asia marginal seas (such as the South China Sea), making it difficult to decipher the different influence of these two processes on the sediment transportation. However, this is not the case in the South Asian area. In the Arabian Sea, the Indian summer monsoon precipitation is mainly forced by the 23-kyr precession cycles, while the sea-level is conservative at 100-kyr eccentricity cycles. Therefore, it is possible to use this different dominant orbital cycles to estimate the different influence of Indian summer monsoon precipitation and sea-level on sediment transportation in the Arabian Sea. 

Dr. Zhaojie Yu from the Institute of Oceanology, Chinese Academy of Sciences, invoked clay mineralogy, detrital grain-size, and Sr-Nd isotopic compositions analysis on sediments from the Laxmi basin, eastern Arabian Sea in order to reconstruct a high-resolution orbital sediment export record to the Indus deep-sea fan and estimate the relative importance of Indian summer monsoon precipitation and sea-level. The sediment sources during glacial-interglacial cycles as well as position and width of turbidite layers were carefully identified, and a high-resolution of smectite/(illite+chlorite) record indicating a balance of sediments inputs from Indus River and Deccan Traps to IODP Site U1457 was established.

The results indicate that more turbidite deposits are accompanied by Indus River sediments during glacial sea-level lowstands, while, conversely, more hemipelagic deposits are associated with Deccan Traps sediments during interglacial sea-level highstands. The wavelet and cross-spectral analyses of smectite/(illite+chlorite) record versus sea-level and Indian summer monsoon suggest a strong mechanistic link between the sea-level variations and sediment transportation from the large river basin to the deep-sea fan, while the influence of monsoon precipitation is subordinate. Such results shed light on the dominant role of sea-level variations in comparing to the summer monsoon precipitation in deterring the sediment transportation from a source-to-sink perspective.

These findings are described in the article entitled Sea level-controlled sediment transport to the eastern Arabian Sea over the past 600 kyr: Clay minerals and SrNd isotopic evidence from IODP site U1457, recently published in the journal Quaternary Science Reviews.

This work was conducted by Zhaojie Yu from the Chinese Academy of Sciences, Université Paris-Saclay, and the Qingdao National Laboratory for Marine Science and Technology, Christophe Colin and Serge Miska from the Université Paris-Saclay, Shiming Wan and Zhaokai Xu from the Chinese Academy of Sciences and the Qingdao National Laboratory for Marine Science and Technology, Rajeev Saraswat from the National Institute of Oceanography, Lina Song from the Chinese Academy of Sciences, Peter Clift from Louisiana State University, Huayu Lu from Nanjing University, Mitchell Lyle from Oregon State University, Denise Kulhanek from Texas A&M University, Annette Hahn from the University of Bremen, Manish Tiwarik and Ravi Mishra from the National Centre for Antarctic and Ocean Research, and Anil Kumar from the Wadia Institute of Himalayan Geology.

The study was supported by IODP France and National Natural Science Foundation of China.

Reference:

  1. Yu, Zhaojie., Colin, C., Wan, S., Saraswat, R., Song, L., Xu, Z., Clift, P., Lu, H., Lyle, M., Kulhanek, D., Hahn, A., Tiwari, M., Mishra, R., Miska, S., Kumar, A., 2019. Sea level-controlled sediment transport to the eastern Arabian Sea over the past 600 kyr: Clay minerals and Sr-Nd isotopic evidence from IODP site U1457. Quaternary Science Reviews 205, 22-34.

About The Author

ZY
Zhaojie Yu

Zhaoji Yu is a researcher associated with the Chinese Academy of the Sciences and Institute of Oceanology.