瓦吉里塔格碳酸岩的Ca-B同位素研究：对塔里木大火成岩省岩浆地幔源区的制约

以短时间内巨量喷发为特征的大火成岩省岩浆通常用地幔柱来解释，然而在大火成岩省岩浆活动晚期，仍有小规模基性岩浆活动并能持续很长时间。前人对于这些晚期基性岩浆的成因研究相对比较薄弱，对于晚期基性岩浆与峰期岩浆的性质差异、岩石圈地幔和俯冲板片是否参与熔融、地幔柱扮演何种角色等问题仍没有得到很好的解决。本项目以瓦吉里塔格碳酸岩为研究对象，主要通过碳酸盐矿物Ca−B−Sr−Nd−Pb−C−O同位素分析，结合全岩以及碳酸盐矿物主量元素、微量元素，揭示瓦吉里塔格碳酸岩的源区特征（包括源区中的CO2来源）。从而全面揭示塔里木地幔柱-岩石圈相互作用过程，进一步完善塔里木地幔柱岩浆作用模型。

Large Igneous Province (LIP) is characterized by outpouring of huge amount of magma over a short period, which can be best explained by the mantle plume model. While during the late period of LIP magmatism, some small-scale mafic magmatism can last for a long time. The origin of this postdated mafic magma is poorly understood. Some problems are still unclear, such as the difference between the postdated magmatism and the peak magmatism, the contribution of lithospheric mantle, subducted slab and the possible role of mantle plume in generation of the postdated magmatism. We plan to focus on the Wajilitag carbonatites in the Tarim LIP. The primary objective of our study is to characterize the nature of the Wajilitag carbonatites (including the sources of CO2 in the mantle sources). A better understanding of the characteristics of Tarim plume magmatism in different stage and further improvement of the Tarim mantle plume model can be achieved in this research.