Tracking the ancient Indian monsoon: investigating the geochemistry of deep-sea sediments from the Bay of Bengal and Andaman Sea

The Indian monsoon is one of the most powerful meteorological phenomena on the planet, affecting the lives of over a billion people. However, its behaviour in the near future under the influence of anthropogenic climate change is uncertain. Can we use lessons from the geological past to further our understanding of monsoon sensitivity to climate change? Using marine sediments recovered from the Bay of Bengal and the Andaman Sea in 2015, and by applying cutting-edge geochemical techniques, we will reconstruct monsoon behaviour during the Plio-Pleistocene. The late Pliocene (~3.5 million years ago) is the most recent period in Earth's history with similar elevated global temperatures and CO2 levels to those predicted for the coming century, and may serve as a useful analogue for near-future climate states. The latest Pliocene to earliest Pleistocene (~3.0-2.4 million years ago) was a time of great global change, witnessing the descent into Northern Hemisphere glaciation ("iNHG") concurrent with a significant drop in CO2. Understanding the response of the Indian monsoon system to iNHG will allow us to test ideas about monsoon sensitivity to evolving boundary conditions such as ice volume and CO2 levels.

The overarching aim is to produce one of the first orbital-resolution reconstructions of the past behaviour of the Indian Monsoon in this region during the Late Pliocene-early Pleistocene. During the project you will learn to apply a combination of sophisticated organic and inorganic geochemical proxies to new deep-sea sediment archives recovered from the Bay of Bengal and Andaman Sea during International Ocean Discovery Program (IODP) Expedition 353. IODP is the world's largest internationally collaborative research organisation and you have the benefit of being immersed within this broad research community. There is ample opportunity for you to develop the project according to your own interests and strengths, with the prospect of applying a range of organic biomarker proxies (e.g., TEX86, UK37, LDI, compound-specific stable isotopes etc.) as well as foraminifera-based proxies (stable isotopes, trace elements etc.) to interrogate past monsoon variability. These new geochemical records will be compared to pollen, charcoal, and microfossil assemblage data from the same samples, generated by international research partners, which will allow a holistic picture of orbitally-paced climate change in the region to be constructed.

You will be embedded within the Deep Time Global Change group at the University of Exeter under the supervision of Drs Littler and Bailey, where facilities for the preparation of sediments for biomarker analysis, along with sediment and foraminifera processing and picking, are available. The student will benefit from substantial involvement with co-supervisors from 3 other institutions, and will have the opportunity to spend significant amounts of time generating organic geochemical data at Bristol, stable isotope data at BGS, and trace element data at the Open University, commensurate with their research interests.