河南登封-方城地区早白垩世镁铁质侵入岩多元同位素研究：对岩石圈地幔属性的制约

幔源镁铁质岩浆是透视岩石圈地幔属性的重要窗口。华北陆块南缘因缺乏中生代镁铁质岩浆作用，对其中生代岩石圈地幔属性与深部作用过程的认识几乎处于空白。然而，华北陆块南缘登封-方城地区早白垩世镁铁质侵入岩的发现，为解决上述科学问题提供了可能。本项目以登封-方城地区原定元古代的早白垩世角闪辉长岩和辉长辉绿岩为研究对象，在详细野外地质调查和岩石学研究基础上，进行锆石U-Pb年代学和岩石地球化学及全岩Sr-Nd-Pb-Hf-Mg同位素分析，同时结合单矿物原位微区多元（斜长石Sr-Pb、磷灰石Nd和锆石Hf-O）同位素体系的综合研究，查明研究区早白垩世镁铁质侵入岩的时空格架，确定早白垩世镁铁质侵入岩的岩石成因，揭示研究区早白垩世岩石圈地幔属性及深部作用过程，并结合区域研究成果，探讨华北陆块南缘中生代岩石圈地幔时空的不均一性及深部壳幔作用过程。该项研究对揭示大陆岩石圈地幔演化过程具有重要意义。

The investigation of mafic magmas is a crucial access to understand the nature of lithospheric mantle. So far, the nature of Mesozoic lithospheric mantle and deep process in the southern North China Block (NCB) have not been evaluated due to the lack of Mesozoic mafic magmatism. However, the identification of Early Cretaceous mafic intrusions in the southern NCB provides a possibility to solve the above scientific problem. Study objects of this project are hornblende gabbros and gabbroic diabases from the Dengfeng-Fangcheng area that were originally dated Proterozoic. Based on the detailed field investigation and petrological research, the U-Pb geochronology, geochemistry and whole-rock Sr-Nd-Pb-Hf-Mg isotopic analyses will be carried out in this study. Together with the in-situ single mineral multi isotopes (Sr-Pb of plagioclase, Nd of apatite, and Hf-O of zircon) data, we will not only ascertain the spatial and temporal framework of the Early Cretaceous mafic intrusive rocks but also constrain their pertrogenesis, as well as discuss the heterogeneity of Mesozoic lithospheric mantle and deep crust-mantle interaction at the southern NCB. By integrating with the regional data, this project must become crucial restrictions for revealing the evolution of continental lithospheric mantle.