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

印度季风是地球上最强大的气象现象之一，影响着超过10亿人的生活。然而，在人为气候变化的影响下，它在不久的将来的行为还不确定。我们能否利用过去地质上的教训来加深我们对季风对气候变化敏感性的理解？利用2015年从孟加拉湾和安达曼海回收的海洋沉积物，并通过应用尖端地球化学技术，我们将重建上更新世期间的季风行为。上新世晚期(约350万年前)是地球历史上全球气温和二氧化碳水平上升的最近时期，与对下个世纪的预测相似，可以作为不久的未来气候状态的有用类比。最晚的上新世至最早的更新世(约300万-240万年前)是全球发生巨大变化的时期，见证了北半球冰川的下降，同时二氧化碳显著下降。了解印度季风系统对汞的响应将使我们能够测试季风对不断变化的边界条件(如冰量和二氧化碳水平)的敏感性。总体目标是对该地区晚上新世-早更新世印度季风过去的行为进行轨道分辨率重建。在该项目中，您将学习如何将复杂的有机和无机地球化学指标组合应用于在国际海洋发现计划(IODP)353远征期间从孟加拉湾和安达曼海发现的新深海沉积物档案。IODP是世界上最大的国际合作研究组织，您可以沉浸在这个广泛的研究社区中。您有足够的机会根据自己的兴趣和优势开发该项目，并有可能应用一系列有机生物标记物的替代品(例如，TEX86、UK37、LDI、化合物特定的稳定同位素等)。以及以有孔虫为基础的替代品(稳定同位素、微量元素等)。询问过去的季风变化性。这些新的地球化学记录将与来自相同样本的花粉、木炭和微化石组合数据进行比较，这些数据由国际研究伙伴产生，这将使我们能够构建该地区轨道进度的气候变化的整体图景。你将被嵌入埃克塞特大学的深度时间全球变化小组，在DRS Littler和Bailey的监督下，那里有准备用于生物标记物分析的沉积物的设施，以及沉积物和有孔虫的加工和采摘。学生将受益于与其他3个机构的合作导师的大量参与，并将有机会花费大量时间生成布里斯托尔的有机地球化学数据、英国地质调查局的稳定同位素数据和开放大学的痕量元素数据，这与他们的研究兴趣相称。

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.