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，在不久的将来，它在人为气候变化影响下的行为是不确定的。我们能否利用过去的地质经验来进一步了解季风对气候变化的敏感性？利用2015年从孟加拉湾和安达曼海回收的海洋沉积物，并通过应用尖端的地球化学技术，我们将重建上新世-更新世期间的季风行为。上新世晚期（约350万年前）是地球历史上最近的一个时期，全球气温和二氧化碳水平的升高与下一个世纪的预测相似，可以作为近期气候状态的有用类比。上新世晚期至更新世早期（约300万- 240万年前）是一个全球大变化时期，北半球冰期（“iNHG”）的下降与二氧化碳的显著下降同时发生。了解印度季风系统对iNHG的反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。总体目标是在上新世晚期至更新世早期，对该地区的印度季风的过去行为进行第一次轨道分辨率重建。在项目期间，您将学习将复杂的有机和无机地球化学指标结合应用于国际海洋发现计划（IODP）远征353期间从孟加拉湾和安达曼海恢复的新的深海沉积物档案。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。您有充分的机会根据自己的兴趣和优势开发该项目，并应用一系列有机生物标志物代用品（例如，TEX86, UK37， LDI，化合物特异性稳定同位素等）以及基于有孔虫的代用品（稳定同位素，微量元素等）来询问过去的季风变化。这些新的地球化学记录将与来自同一样品的花粉、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生成，这将使该地区的轨道节奏气候变化的整体图景得以构建。你将在埃克塞特大学的深时间全球变化小组工作，在Littler和Bailey博士的监督下，那里有用于生物标志物分析的沉积物准备设施，以及沉积物和有孔虫的处理和采集设施。该学生将受益于与其他3个机构的共同导师的大量参与，并将有机会花大量时间在布里斯托尔获得有机地球化学数据，在英国地质调查局获得稳定同位素数据，在开放大学获得微量元素数据，这些数据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.