氧同位素（MIS）11-12期（距今38-48万年）包含了晚更新世以来两个极端气候时期，极温暖的MIS 11期和极寒冷的MIS 12期。在此期间，北大西洋深层水生成强度发生了巨大变化，从MIS 12期最弱到MIS 11期最强。北大西洋深层水是大洋温盐环流的“开关”，探索其在极端气候条件下的演化机制有助于理解气候系统稳定性及推测未来气候变化趋势。而高温高盐的地中海溢出流自直布罗陀海峡进入北大西洋，最远至挪威-格陵兰海，促进了北大西洋深层水的生成，是北大西洋深层水的重要来源。本研究以受地中海溢出流影响的葡萄牙岸外U1391站位岩心沉积物为材料，对MIS 11-12期高分辨率有孔虫壳体稳定氧碳同位素、Mg/Ca比值、沉积物粒度以及底栖有孔虫群落等进行分析，重建该时期葡萄牙岸外底层水温度、盐度、水动力及底层水团演化过程，通过与北大西洋深层水记录进行对比，揭示地中海溢出流对北大西洋深层水的影响机制。

The time interval, marine isotope stages (MIS) 11-12 (ca. 380-480 ka), characterized by the most extreme glacial and interglacial climate conditions of the late Pleistocene, contains the warmest interglacial MIS 11 and the most severe glacial MIS 12. During this time interval, great changes in the strength of North Atlantic Deep Water (NADW) production occurred, from the most severe reduction during MIS 12 to its maximum during MIS 11. Since NADW is the switch of global ocean thermohaline circulation, figuring out its variation mechanism on millennial scale in extreme climate conditions contributes to understanding the stability of climate system and inferring the trend of future climate change. High-temperature and salty Mediterranean Outflow Water (MOW) flows northward along the western Iberian margin after entering the North Atlantic Ocean through the Strait of Gibraltar, and reaches as far as the Norwegian-Greenland Sea, thus contributing to the production of NADW, which provides a clue to uncover the variation mechanism of NADW. In this study, foraminiferal stable oxygen and carbon isotopes, Mg/Ca ratio, grain size of the sediments and benthic foraminiferal assemblages at IODP Site U1391 off the Portuguese margin in the distal area of MOW will be analyzed, to reconstruct the change processes of bottom water temperature, salinity, dynamics and water masses during MIS 11-12, and uncover the influencing mechanism of MOW on NADW in the transition from MIS 11 to MIS 12 by comparison with the record of NADW.