浙西开化地区桐村花岗斑岩LA-ICP-MS锆石U-Pb年龄及其地质意义

报道了浙西开化地区桐村含Cu、Mo花岗斑岩的LA-ICP-MS锆石U-Pb年龄,2个样品加权平均年龄介于167.6~155.6 Ma之间,反映花岗斑岩形成于中、晚侏罗世。该时期同时又是燕山运动活跃的时期,区域构造以北西—南东向挤压为特征,形成走向北东的压性断裂和配套的南东向张性断裂。2组断裂交会产生的应力薄弱区为燕山期发生的规模性岩浆活动提供了侵位通道。因此,浙西地区拥有良好的构造和岩浆成矿条件,成矿潜力巨大。

LA-ICP-MS zircon U-Pb dating of the Tongcun porphyry in Kaihua County,western Zhejiang Province,and its geological significance

This paper reports the LA-ICP-MS zircon U-Pb ages of granite porphyry in Tongcun, Kaihua County, Zhejiang Province. The age ranging from 167.6 to 155.6 Ma suggests an intrusion process of magma in Middle and Late Jurassic. Jurassic was a tectonic active period during the Yanshanian movement. Regional tectonic stress field of that time characterized by NW-trending extrusion and NE-trending tension formed a series of NE extrusion faults and NW-trending tension faults. The intersection of faults, known as the weak stress area, provided essential invasive channels for large-scale magmatic intrusion in Mesozoic. Therefore, the Tongcun ore deposit not only represents a typical case of Jurassic molybdenum mineralization in west Zhejiang Province but also indicates a very optimistic prospect of mineralization, because magmatic and tectonic activities were very active in Jurassic.