Project Details
Projekt
Evolution of the Indian summer monsoon and terrestrial vegetation in the Northeastern Indian region during the mid-Pleistocene transition (INTERMILAN)
Applicant
Ilham Bouimetarhan, Ph.D.
Subject Area
Palaeontology
Term
from 2016 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 320220536
The primary objective of the proposed project is to reconstruct past behavior of the Indian summer monsoon (ISM) circulation during the last 1.2 million years at orbital to centennial timescales. During this interval, low-amplitude 41 ka obliquity-forced climate cycles between 2.8 and 0.9 Ma were replaced progressively by high-amplitude 100 ka cycle increasing severity and duration of cold stages, which has substantially influenced the biota and different ecosystems. Previous studies have shown that changes in atmospheric moisture content driven by the strengthening/weakening of the monsoon controlled precipitation and vegetation development as well as considerable changes in sea surface salinity, implying strong interactions between the solid earth, oceanic and atmospheric processes. However, continuous and high temporal resolution records from the core convective region of the Indo-Asian monsoon system, which have the potential to document the detailed evolution of the ISM, were lacking prior to the IODP Expedition 353. This project aims at understanding Pleistocene changes of the ISM through high resolution records of large-scale vegetation changes and terrestrial hydrology of northeastern India as well as past sea-surface ecological changes in the northern Bay of Bengal for two key periods; the mid-Pleistocene transition (MPT) and the last interglacial/glacial cycle, using marine sediments of IODP site U1446. This palynological study should provide insights into the long-term interaction processes in the marine and adjacent terrestrial realm allowing for a direct land-ocean-atmosphere correlation. It would, thus, offer an important complement to the almost exclusively paleoceanographic (foraminifera and isotopes) multi-proxy studies investigated by expedition scientists of the IODP Expedition 353. Despite the fact that marine palynology provide a powerful tool to reconstruct past variations in the ISM magnitude and frequency and to advance our current understanding of different forcing mechanisms, good data sets of pollen/spores and organic dinoflagellate cyst assemblages are (as good as) non-existent for the core convective region of the monsoon system during those time intervals with major re-organizations in the atmosphere, oceans, cryosphere and biosphere.
DFG Programme
Infrastructure Priority Programmes
