华北克拉通赞皇地区新太古代绿帘岩成因及大地构造意义

绿帘岩可产出于俯冲碰撞带、大洋中脊等多种构造背景，其识别可为研究区大地构造环境提供重要约束，而且它通常形成于热液成矿系统底部，伴随着元素迁移，多与铜金属矿床和块状硫化物矿床形成关系密切，具有重要找矿指示意义。本项目以申请人在华北克拉通赞皇地区新近识别出的一套产出于新太古代构造赞皇混杂岩中的绿帘岩团块为研究对象，拟通过详细野外构造解析为基础的大比例尺岩石构造填图，解析绿帘岩团块与混杂岩内部不同岩石构造单元的构造成因关系，并通过LA-ICP-MS锆石U-Pb年代学测试限定绿帘岩形成时代，结合岩相学、岩石地球化学及氧同位素分析，恢复绿帘岩原岩类型，分析绿帘岩成因，并检验是否与成矿作用有关，进而探讨研究区大地构造环境，为长期存在争议的华北克拉通早前寒武纪大地构造演化、乃至太古宙增生型造山带大地构造演化规律研究提供关键地质依据。

Epidosites can form in specific tectonic settings, such as subduction collision zones and mid-ocean ridges. Therefore, their identification can provide important constraints for determining the tectonic environment of a rock assemblage. Epidosites usually form at the bottom of a hydrothermal mineralization system, where different elements can migrate. Thus, the formation of epidosites is closely related to formation of copper ore deposits or massive sulfide deposits, and has important significance for prospecting for these deposits. The epidosites in this study have been recently documented in the Neoarchean tectonic mélange belt in the Zanhuang Massif of the North China Craton. Based on detailed and large-scale field litho-structural mapping of targeted outcrops where epidosites are concentrated, this project will analyse the structural relationships between epidosites and different litho-structural units of the Zanhuang Neoarchean mélange. The formation age of the epidosites will be constrained by LA-ICP-MS dating of zircons collected from epidosites. Combining the analysis of lithology, geochemistry and isotope geochemistry, we plan to determine the protolith and petrogenesis of the epidosites, examine whether they are related to mineralization or not, and further discuss the tectonic environment of the study area. This project will also provide key geological evidence for the long-term controversial study on early Precambrian tectonic evolution of the North China Craton and even the Archean accretionary orogenic belt.