The Impact of Northern Hemisphere Glaciation on Intermediate and Deep Ocean Circulation

北半球冰川作用(InHg)的加剧是北半球大部分地区在新生代首次被冰覆盖的过程。这是过去5 Ma以来最大的长期气候变化。了解支配这一过程的过程将有助于更好地了解气候动态，从而为我们未来的气候变化做好准备。在inHg上，北太平洋和大西洋的深水和中水之间的水团性质有一个交汇点。这被认为是由于北太平洋或南大洋的强迫所致。该项目的目的是观察西北太平洋的1209号站点，使用微量元素分析来确定该站点上覆盖的水团的温度、碳储量和来源。这应该说明北太平洋的环流在inHg期间发生了怎样的变化。这个地点与大西洋中部925、927和929地点的放射性同位素记录进行比较，可以推断这两个大洋之间的连通性是如何在inHg上发生变化的。最后，通过对981和982地点的火山灰层数量的统计分析，该项目打算了解汞是如何影响冰岛火山活动的速度的。

The intensification of Northern Hemisphere Glaciation (iNHG) is a process where much of the Northern Hemisphere was covered in ice for the first time in the Cenozoic. It is the largest secular climate shift over the last 5 Ma. Understanding the processes that govern this will help to better understand climate dynamics which can prepare us for future climate changes. Over the iNHG, there is a convergence in water mass properties between the deep and intermediate North Pacific and Atlantic Oceans. This is thought to be due to either North Pacific or Southern Ocean forcings. This project aims to look at Site 1209 in the Northwest Pacific using trace element analysis to determine the temperature, carbon storage and provenance of water masses overlying the site. This should show how circulation in the North Pacific changed over the iNHG. Comparison between this site and radiogenic isotope records from Sites 925, 927, and 929 in the mid-Atlantic can be used to infer how connectivity between these two oceans changed over the iNHG. Finally, through statistical analysis of the number of tephra layers at Sites 981 and 982, this project intends to see how the iNHG affected the rate of volcanism in Iceland.