印尼穿越流是全球温盐环流在低纬海区的关键组成部分，调节着西太平洋和印度洋之间热量和淡水的收支，在低纬海区乃至全球的气候变化中扮演着十分重要的角色。现代海洋学观测和末次冰期以来的古海洋学记录均显示印尼穿越流的水体结构和强弱变化与东亚季风和ENSO等气候现象密切相关。在3.6-2.4Ma北半球冰盖扩大期间，新几内亚向北移动增加了印尼海道的封闭程度，可能导致印尼穿越流受到限制、和海水来源的重大改变，继而影响全球气候。但目前缺乏长时间尺度的印尼穿越流古海洋学记录予以证实。项目以“国际大洋钻探计划”U1482站沉积物为材料，利用浮游有孔虫表层和次表层水种壳体的氧同位素和Mg/Ca比值等数据、结合底栖氧同位素地层，重建4-2Ma 涵盖北半球冰盖扩大期印尼穿越流的古海洋学记录，探讨印尼穿越流与北半球冰量增长、印尼海道的封闭程度、西太平洋暖池变动、以及东亚古季风演化等构造和气候因素之间的联系和反馈机制。

As the key component of the global thermohaline circulation in the low latitudes, the Indonesian Throughflow (ITF) acts as the unique connection between the western Pacific and Indian Oceans and regulates their heat and fresh water budgets, subsequently playing a crucial role in the low latitudes and even global climate change. It is indicated, by modern oceanographic observations and paleoceanographic records covering the last glacial to the present, that water structure and intensity of the ITF is closely associated with climatic phenomena such as East Asian monsoon and El Niño-Southern Oscillation. Concomitant with the Northern Hemisphere Glaciation (3.6-2.4Ma), northward movement of New Guinea caused closure of the Indonesian Seaway, possibly resulting in restricted ITF and significant change in sources of ITF seawaters, which was suggested to strongly influenced evolution of Earth’s climate. This hypothesis has been indirectly testified, but long-timescale records of the ITF are still absent. Here, we propose to work on sediments from cores of Site U1482 that were retrieved during the International Ocean Discovery Program (IODP) Expedition 363. We will reconstruct records of the ITF at 4-2 Ma ago, including the period of Northern Hemisphere Glaciation, based on stable isotopes and Mg/Ca ratios on shells of planktonic foraminiferal surface and subsurface species against benthic oxygen isotope stratigraphy. The proposal targets to investigate evolution of the ITF with respect/feedback to tectonic and climatic factors, including increase of Northern Hemisphere ice volume, restriction of the Indonesian Seaway, dynamics of the western Pacific warm pool and the East Asian paleo-monsoon.