NSFGEO-NERC: Impact of the Plio-Pleistocene Transition on Provenance and Sediment Routing from the Himalaya to the Deep-Sea Bengal Fan

喜马拉雅山脉是地球上最大的山脉，主要分布在尼泊尔、印度、巴基斯坦和中国。数百万年前，当印度与亚洲碰撞时，喜马拉雅山开始上升，这改变了地球的气候，改变了海洋环流和化学，并影响了生物进化的进程。喜马拉雅山的侵蚀导致地球上最大的沉积物堆积在孟加拉湾，深海孟加拉扇。这些沉积物记录了喜马拉雅山脉的历史——现在被侵蚀的过去的珠穆朗玛峰，埋在大陆架和印度洋最深处的沉积物下。2015年，一艘专门设计的钻探船“乔迪斯决议号”（Joides Resolution）进行了一次多国考察，回收了约1.5英里的钻芯，其中包含了这一记录。新的研究将利用这些岩心的沉积物来追踪喜马拉雅侵蚀的历史，以及世界上最大的两条河流——恒河和雅鲁藏布江——在过去的300万到500万年里是如何将这些沉积物输送到孟加拉湾的。在地质历史上，像喜马拉雅山这样的巨大山脉是罕见的，但没有喜马拉雅山，就没有亚洲季风，没有肥沃的洪泛平原或含水层，没有古老的印度河文明，也没有世界上那个地区的珠穆朗玛峰。因此，这项研究的结果将告诉我们气候变化、景观演变，以及世界上人口最稠密的地区之一是如何变成我们今天看到的样子的。以这种方式了解过去可以帮助我们更好地了解生活在这一令人难以置信的地理特征影响下的世界10%人口的未来。

The Himalayas represent the largest mountain chain on Earth, and reside mostly in Nepal, India, Pakistan and China. The Himalayas began rising many millions of years ago when India collided with Asia, which changed Earth's climate, altered ocean circulation and chemistry, and impacted the course of biological evolution. Erosion of the Himalayas resulted in deposition of the largest pile of sediment on the planet in the Bay of Bengal, the deep-sea Bengal Fan. Within this sediment record lies the history of the Himalayas - the now eroded Mt. Everests of the past, buried under sediment of the continental shelf and the deepest parts of the Indian Ocean. In 2015, a multi-national expedition on the Joides Resolution, a specially designed drill ship, recovered ~1.5 miles of drill core that contains this record. New research will use sediment from these cores to trace the history of Himalayan erosion and how two of the world's largest rivers, the Ganges and Brahmaputra, delivered this sediment to the Bay of Bengal over the last 3-5 million years. Giant mountain ranges like the Himalayas are a rarity through geologic history, but without the Himalayas there are no drenching Asian monsoons, no fertile floodplains or aquifers, no ancient Indus Civilization, and no Mt. Everests in that part of the world. The results of this research will therefore tell us about climate change, landscape evolution, and how one of the world's most densely populated areas came to be as we see it today. Understanding the past in this way can help us better understand the future for the 10% of the world's population that lives under the influence of this incredible geographic feature.