Orbital-Scale Paleoceanographic Response to the Indian Monsoon in the Laxmi Basin of the Eastern Arabian Sea

International Ocean Discovery Program Expedition 355 performed a 1109.4 m penetration drill at Site U1456 in the Laxmi Basin of the Eastern Arabian Sea. The uppermost section (*121 m thick) was analyzed for the paleoceanographic change in response to the orbital-scale Indian monsoon. Correlation of d¹⁸ O values of planktonic foraminifera (Globigerinoides ruber) to the LR04 stacks determined the age model (*1.2 Ma). The geochemical contents correspond to the sediment facies such that high TC contents correspond to the pelagic carbonates. High d¹⁵ N values of bulk sediments coincide with the interglacial periods when denitrification was intensified.⁸⁷ Sr/⁸⁶ Sr ratios and eNd values of detrital particles are controlled by the sediment sources (i.e., river sediments) as well as depositional processes. Mixed layer depth traced by d¹⁸ O and d¹³ C values between G. ruber and G. sacculifer varied in response to the monsoon activity. The sediments in the Laxmi Basin of the Eastern Arabian Sea record the orbital-scale variation of the Indian monsoon during the Pleistocene.