中新世碳酸盐崩溃事件（12~9 Ma）导致全球海洋沉积物碳酸钙剧降和钙质化石的溶蚀，但其发生机制仍不清楚。本项目立足南海、瞄准全球，围绕“印尼海道构造抬升的海洋和气候效应”科学假设，利用2017年国际大洋发现计划（IODP）368航次在南海获得的连续沉积记录，结合赤道太平洋DSDP588和ODP844，研究15-6Ma期间古海洋条件的时空变化。在钙质超微生物地层年代基础上，利用超微、硅藻、CaCO3%、总有机碳及其δ13C表征生产力，浮游有孔虫标准化壳体重量估算海水溶解力，浮游有孔虫壳体Mg/Ca比值计算海表温度。比较研究海表生产力、温度和海水溶解力的时空变化，探索初级生产力、碳酸盐溶解保存、气候变化、原始暖池形成、海道受限、构造抬升等一系列过程之间的关系，以海洋碳酸盐体系动态平衡和全球碳循环为纽带，阐述构造-洋流-气候-生物之间的相互作用，揭示中新世全球碳酸盐崩溃事件统一的成因机制。

The middle Miocene carbonate crash (12~9 Ma) caused a sharp reduction in carbonate content and severe dissolution of calcareous fossils in global oceanic sediments, yet its causal mechanism remains unclear. This project is based on the South China Sea and aims at the global oceans to test the hypothesis on the oceanographic and climatic effects of the tectonic constriction of Indonesian Seaway. We propose to investigate the paleoceanographic change during 15-6 Ma, using the continuous sediment archives from South China Sea drilled during the International Ocean Discovery Program (IODP) Expedition 368 in 2017, and those from DSDP Site 588 and ODP Site 844 in the equatorial Pacific. Based on the chronology via calcareous nannofossil biostratigraphy, surface ocean productivity is comprehensively estimated using nannofossil and diatom assemblages, CaCO3 percentage, and total organic carbon and its δ13C values; seawater solubility and sea-surface temperature (SST) are quantified through planktonic foraminiferal size-normalized weight (SNW) and Mg/Ca ratios, respectively. A cross-site comparison among the spatiotemporal variations of surface ocean productivity, SST and seawater solubility will be conducted, aiming to explore the relationships among a series of processes including primary productivity, carbonate dissolution and preservation, climate change, formation of proto-warm pool, constriction of Indonesian Seaway, and tectonic uplift. Based on the dynamic balance of marine carbonate system and the global carbon cycle, we will elaborate the interactions between tectonics, ocean currents, climate and biology, which supposedly lead to a universal causal mechanism of the global carbonate crash event.