Variations in South Asian Monsoon over the last 13 kyr inferred from biogeochemical properties of maar sediment in the central highland of Vietnam
Monday, June 15, 2015
Hiroyuki Kitagawa, Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan, Dang Xuan Phong, Institute of Geography, Vietnamese Academy of Science and Technology, Hanoi, Vietnam, Akira Hayashida, Faculty of Science and Engineering, Doshisha University, Kyotanabe, Japan and Toshio Nakamura, Nagoya University, Nagoya, Japan; Center for Chronological Research, Nagoya University, Nagoya, Japan
Abstract:
It is demanded to understand how the South Asian summer monsoon rainfall has changed because more than one billion people across South Asia can be impacted by the South Asian monsoon (SAM) rainfall variation. The Pleiku volcanic complex in the central highland of Vietnam was built up by two major eruptive episodes in 6.5-3.4 Ma and 2.4-0.2 Ma. More than 10 maar (including no-flooded (or paleo) maar of old volcanos) are distributed on the Pleiku volcanic complex. The sediments deposited in the maars have great opportunity to trace a long-term change of the SAM rainfall. In 2013, a 7-m continues sediment core (PLK13) was collected from a semi-dried maar on the Pleiku volcanic complex. The sediment core was divided into every 2.2 cm and 10 well-preserved macrofossils were picked up for radiocarbon dating and age-depth model construction. The geochemical (elemental and isotope) analyses and infrared spectroscopic analysis for inferring the biogeochemical properties were carried out on 313 samples. We will report the SAM changes during the last 13 kyr based on the changes of biogeochemical properties of maar sediment.
