Pliocene history of the Indian Monsoon: new data from IODP Expedition 353

GSTDTAP

项目编号	NE/N012100/1
	Pliocene history of the Indian Monsoon: new data from IODP Expedition 353
	[unavailable]
主持机构	University of Exeter
项目开始年	2016
	2016-01-27
项目结束日期	2016-12-31
资助机构	UK-NERC
项目类别	Research Grant
国家	英国
语种	英语
英文摘要	It is important to understand how Earth's climate varied during past periods of higher atmospheric CO2, so we can better predict how the climate might evolve in the near future due to human activity. Of particular concern is the future behaviour of the Asian Monsoon, which in the modern world provides water for, and influences the lives of, billions of people. The response of the monsoons to higher CO2 and global temperatures is unknown, but latest modelling results suggest that the summer monsoon will get stronger and more prolonged, raising the possibility of severe and widespread flooding, as seen in India in 2013 and Pakistan in 2015. Past temperature and rainfall patterns associated with the Indian Monsoon can be reconstructed by studying marine sediments recovered from deep-sea cores in the basins surrounding the Indian subcontinent. New sediment cores have been recovered from the NW Indian Ocean region, including the Bay of Bengal and the Andaman Sea, during International Ocean Discovery Program (IODP) Expedition 353 (Dec 2014-Jan 2015). The aim of this expedition is to try and understand the past behaviour of the Indian Monsoon from the Holocene to the late Miocene (present day to 10 million years ago), by taking cores in a part of the Indian Ocean that has never been scientifically drilled before. By examining the geochemistry and microfossil content of the sedimentary cores, and indeed the composition of the sediments themselves, many interesting features of the ancient ocean and monsoons that influence them can be reconstructed. For the overarching project, we propose to examine the geochemistry and sedimentology of sediments from two sites cored during IODP Exp. 353, Sites U1445 of the NE coast of India and Site U1448 in the Andaman Sea, with the aim of reconstructing the rainfall and temperature patterns associated with the Indian Monsoon during the enigmatic Pliocene period (~5.4-2.6 million years ago). This time period was the most recent in Earth's history where atmospheric CO2 levels were similar to those predicted for our near future, and so it may be a good model for predicting how the Asian monsoons will behave as the Earth heats up in the coming century. By taking sediment samples of Pliocene age and applying sophisticated organic geochemical techniques, we will reconstruct the sea surface temperature (SST) and the rainfall intensity at very high resolution, which will increase our understanding of how the monsoon affected the Indian during a time of great global environmental change. Using this new organic geochemistry data, we will be able to see how the Indian monsoons responded to repeated heating and cooling cycles (glacials and interglacials) triggered by the change in Earth's orbit around the sun. Specifically in this grant, we first need to determine exactly how old the sediments are before we can apply the organic geochemistry techniques. To do this we will generate stable oxygen isotope data from the shells of microfossils (foraminifera), which we can then compare to a global reference set that has been calibrated to orbital-forcing, in order to generate an "orbitally-tuned" aged model. This age model will be the foundation block on which all subsequent data, and our deeper understanding of the Indian Monsoon, is built.
来源学科分类	Natural Environment Research
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/86012
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	[unavailable].Pliocene history of the Indian Monsoon: new data from IODP Expedition 353.2016.