A synthesis of paleomonsoon and associated processes from the unique depocenter, Andaman Sea

Abstract

The Andaman Sea is a unique deep basin with limited connectivity with the global ocean. The riverine influx from the major rivers draining from the surrounding Asian landmass combined with a large amount of rainfall during the summer monsoon season strongly affects the Andaman Sea. The biogenic carbonate-rich sediments with ample terrigenous material ensure the potential applicability of a wide range of proxies to reconstruct the past. Thus, the Andaman Sea is an excellent archive to reconstruct the past monsoon and associated processes. The isolated nature of the deeper regions provides a unique opportunity to understand deep water changes, without the usual influence of the Antarctica and North Atlantic Ocean. The presence of both the aerial and sub-marine volcanoes in the Andaman Sea makes it an interesting region to understand the temporal changes in the climate-tectonics interaction. Here, we synthesize the paleomonsoon and associated studies from the Andaman Sea. A majority of the paleoclimatic studies from this region are restricted to the last glacial-interglacial transition, with limited attention being paid to the long-term changes. The provenance of fresh water and sediments reaching the Andaman Sea varied during glacial-interglacial times. A few coral and speleothem-based studies provide high-resolution records of the past monsoon from the Andaman region. The limited drilling during the last expedition to the Andaman Sea (Site U1447 and U1448) was restricted to a relatively shallow depth. The region requires both high-resolution and long-term paleoclimatic studies based on several more drill holes covering a range of depths and latitudinal zones.