摘要
龙泉站金矿床位于郯庐断裂带山东段内中段，为沂沭断裂金成矿带的重要组成部分，同时也是目前沂沭断裂带内发现的唯一一个碎裂蚀变岩型金矿，矿体主要产于沂水一汤头断裂内的破碎带以及下盘变质岩系中．应用Rb-Sr同位素定年方法对该矿床10件黄铁矿样品进行了成矿时代测定，获得黄铁矿Rb-Sr同位素等时线年龄为96±2Ma（MSWD=1．2），该年龄与断裂带内及附近目前发现的早白垩世晚期至晚白垩世早期岩浆活动时限（106～96Ma）相吻合．同时结合近些年来山东省成岩成矿的高精度年代学以及矿产勘查成果资料，表明华北克拉通东南缘亦存在晚白垩世金成矿作用．成矿构造背景与该时期沂沐断裂带不断引张及减压环境有关．伸展机制可能导致断裂带内及附近软流圈不断抬升，等温线升高，其进而诱发的强烈壳幔作用为金成矿提供了物质和流体来源．龙泉站晚白垩世金成矿事件的确定，也为郯庐断裂带内及其两侧矿床成因对比和找矿实践提供了参考．
Longquanzhan gold deposit, an important part of gold mineralization belt of Yi-Shu fault zone, is the only altered tec- tonite-type gold deposit discovered in the area at present. The ore bodies mainly occur at the fracture zone and the footwall met- amorphic rocks. Rb-Sr isotopic dating of 10 pyrites separated from the Longquanzhan gold deposit yields an isochron age of 96=}=2 Ma （MSWD= 1.2）, which is in good agreement with the late Early Cretaceous to early Late Cretaceous magmatism （106--96 Ma） in adjacent area of Yi-Shu fault zone. Meanwhile, combining with the precise ages of gold deposits in Shandong Province and mineral exploration data, we suggest that late Early Cretaceous gold mineralization may occur in the southeastern margin of North China Craton, and its tectonic setting is related to an extensional setting which resulted in a large-scale asthe- nosphere upwelling, accompanying decompression and isotherm upwelling, material exchange and mixing between mantle and crust, and finally providing a great amount of ore-forming fluids and materials for gold mineralization. According to the precise age of Longquanzhan gold deposit reported, this discovery is of great significance both in gold deposit origin contrast of both sides and future mineral exploration.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2014年第3期325-340,共16页
Earth Science-Journal of China University of Geosciences
基金
中国地质大学(武汉)高等学校博士学科点专项科研基金(No.20120145110004)
中央高校基本科研业务费专项资金(Nos.CUG120702
CUG120842)
中国博士后科学基金(No.2012M521493)
