上新世/更新世之交太平洋经向翻转流演化

随着北半球冰盖的发育，全球气候环境发生了显著变化。太平洋经向翻转流（PMOC）对全球海洋热量分配和大气CO₂在深海的封存起举足轻重的作用，但是关于PMOC与北半球冰盖的形成之间的关系还欠缺研究。本文收集了太平洋海山富钴结壳的Nd同位素记录，通过对比不同区域Nd同位素记录的演化特征，分析风尘输入、水团演化等因素对Nd同位素记录的影响，探讨了太平洋经向翻转流演化及其与全球气候变化之间的关系，认为北太平洋深层水下沉的停滞和亚洲风尘输入增加可能是导致深层水Nd同位素从距今3～4 Ma开始降低的原因。同时，因北太平洋深层水下沉停滞，PMOC改组，使得更多的CO₂在深水封存，从而对全球气候变冷和北半球冰盖形成产生了积极的贡献。

Evolution of the Pacific meridional overturning circulation during the Plio-Pleistocene transition: Nd isotope records from the Fe-Mn crust

The global climate and environment have changed significantly upon the development of the Northern Hemisphere glaciation (NHG) during the Pliocene/Pleistocene. The Pacific meridional overturning circulation (PMOC) plays an important role on the distribution of heat in the global ocean and atmospheric CO₂ sequestration in the deep ocean, however, the relationship between PMOC and the formation of NHG is poorly studied. In this paper, we collected the available Nd isotope data of seamount Fe-Mn crusts from the Pacific. By comparing the Nd isotopic records from different water depths and different regions of the Pacific, considering the influences of water mass evolution and dust input on the Nd isotope records, we discuss the evolution of the PMOC and its relationship with the global climate change. It is suggested that the stagnation of the deep water formation in the North Pacific and the increase of the Asian dust input may be the reasons for the decline of the εNd of the North Pacific deep water since 3～4 Ma, and the increase of CO₂ sequestration in the deep ocean caused by the weakening of the deep water ventilation in the North Pacific contribute to the global cooling and the formation of NHG.