鄂霍次克海中层水百年-千年尺度上动力学演化的环境磁学记录

Okhotsk Sea Intermediate Water(OSIW) is investigated by combined methods from environmental magnetism, paleoceaography and sedimentology. The main focuses are the processes of dynamic evolution including relative strength, direction of OSIW and the variation in terrigenous flux, composition and sources transported by OSIW. On the high resolution relative paleointensity of the sediments, we will recover the changes of relative intensity, direction of OSIW and its spatial pattern and temporal evolving rules to probe its relationship with terrigenous flux, components and sources. And even further to elucidate the relationship between OSIW and Bering Sea Intermediate Water(another source of North Pacific Intermediate Water in glacials), with North Pacific Intermediate Water(NPIW) to resolve the problem that whether the NPIW is ventilated by singel source(Bering Sea) or multiple sources (Okhotsk Sea and Bering Sea) in glacials. With the high resolution data about OSIW dynamics, we will discuss the connection between OSIW evolution and the climatic events at centennial-millennial and orbital scales and the possible relationship of cause and effect, therefore forcing mechamisms between them by phase relationship. As the ventilation source of modern North Pacific, the OSIW evolution is cruicial for understanding NPIW and its reverse circulation, regional and global climate changes.

利用环境磁学为主、古海洋学和沉积学为辅的综合手段对鄂霍次克海中层水进行从定性到半定量的渐进示踪，从强度变化、绝对方向及与之相对应的陆源因子通量、组成和源区变化等多角度反演中层水的动力学演变过程。在高分辨率地磁场相对强度年龄标尺上，恢复最后两个冰期鄂霍次克海中层水在百年-千年尺度上的相对强度、方向变化、空间分布格局及时间上的演变规律，及其与陆源输入、组成和源区的联系，揭示其在冰期-间冰期气候旋回和短尺度气候突变过程中自身的演化规律和控制因素，进一步阐明其与白令海中层水（冰期的北太平洋中层水源头）、北太平洋中层水演化的关系，解决冰期时北太平洋中层水是"单源"还是"多源"问题。探讨鄂霍次克海中层水与短尺度、轨道尺度气候事件和古环境变迁的联系，通过相位关系揭示环流与气候间的因果关系和驱动机制。作为现代北太平洋通气源头，鄂霍次克海中层水演化过程对北太平洋中层水及其翻转环流以及区域-全球气候变化极重要

现代鄂霍次克海中层水（OSIW）是西北太平洋中层水的主要来源，是驱动远东太平洋和边缘海上-中层水体通气的重要动力。对于冰期鄂霍次克海中层水对于北太平洋中层水的贡献则意见分歧。一种认为冰期鄂霍次克海中层水加强；另一种认为白令海中层水对北太平洋中层水起决定作用。由于碳酸盐遭受深部太平洋水团（PDW）的侵蚀，承载水团信息的底栖有孔虫在鄂霍次克海保存状态不佳，较难作为水团研究的突破点。本研究基于已有的钻孔材料和初步结果，利用环境磁学、沉积学等方法，反演最近两个冰期旋回以来鄂霍次克海中层水在冰期-间冰期尺度上的变化及其与区域环境、全球气候之间的耦合关系。