地幔化学不均一性揭示了南半球（印度洋-南大西洋）地幔DUPAL同位素异常，然而其成因存在争议。从时间尺度上追踪地球历史上地幔DUPAL异常的演化进程将为研究DUPAL异常成因找到突破口，而蛇绿岩则是最佳研究对象。本项目拟选择新疆北部两处代表性的古亚洲洋蛇绿岩，对其中MORB型基性岩和变质橄榄岩进行全岩和单矿物主微量元素及Sr-Nd-Pb-Os同位素研究，厘定古亚洲洋地幔域西段是否存在晚古生代的"DUPAL异常峰"，进而结合蛇绿岩同位素年代学进一步追踪DUPAL异常随时间的演化进程，最终探讨DUPAL异常可能的成因。本项目将为理解古生代期间古亚洲洋地幔归属和中亚造山带深部地球动力学背景提供重要的科学依据。

Available geochemical data indicate that the so-called DUPAL isotopic anomaly in the Earth's mantle exists in the Indian and South Atlantic sub-oceanic mantle in the southern hemisphere. However, the origin of such a global isotopic anomaly is still controversial. Tracing the location and evolution of the DUPAL mantle through time offers a new perspective on the DUPAL study as it will lead to a better understanding of the origin of the anomaly. Ophiolites, pieces of ancient oceanic lithosphere, provide unique opportunities to conduct this kind of study because they extend the isotopic information recorded by the mantle back in time. This project will focus on two Paleo-Asian Ocean ophiolites from the Northern Xinjiang region of China. We plan to analyze the major and trace elements and Sr-Nd-Pb-Os isotopic ratios of the bulk rock and mineral separates from MORB-type mafic rocks and peridotites in these ophiolites in order to constrain whether the Paleo-Asian sub-oceanic mantle existed a "DUPAL peak" during the late Paleozoic. Moreover, these information combined with ophiolite geochronologic data will provide tracers on the evolution of the DUPAL mantle through time and this in turn will provide stringent constraints on the possible cause of the DUPAL anomaly. Therefore, this project will promote geodynamic research in Central Asia as it will provide precise geochemical information on the crustal and mantle conditions in the Paleo-Asian Ocean and Central Asian Orogenic Belt during the Paleozoic.