黔西南贞丰水银洞基性岩锆石U-Pb测年及金矿成矿

基性岩与金矿成矿关系密切。而针对滇黔桂地区卡林型金矿成矿年龄一直缺乏年代学证据。测得黔西南贞丰水银洞基性岩锆石U-Pb年龄为218±3.2 Ma,与前人对水银洞卡林型金矿年龄的测定一致,说明该区金矿化与基性岩岩浆活动密切相关。该年龄对应印支晚期,并在此基础上提出一种印支期成矿的动力学模型:古特提斯洋封闭导致印支板块与扬子板块碰撞,强大的区域构造事件为矿化提供了动力,形成了贞丰地区218±3.2 Ma的基性岩。另外该地区可能存在一些埋藏的印支期花岗岩侵入体,这些入侵的岩体可作为热源,驱动主要为大气降水成因的流体浸出成矿元素,形成了贞丰水银洞地区卡林型金矿床。

Zircon U-Pb dating and gold mineralization of basic rocks in Zhenfeng Shuiyin cave, southwest Guizhou

Basic rocks are closely related to gold mineralization. However, there is no chronological evidence for the mineralization age of the Carlin-type gold deposits in the Guizhou, Yunnan and Guangxi area. The zircon U-Pb age of the basic rocks of the Zhenfeng Shuiyin cave in southwestern Guizhou is 218±3.2Ma, which is compared with the predecessors. The determination of the age of the Carlin-type gold deposits is consistent, indicating that the gold mineralization in this area is closely related to the basic magmatism. This age corresponds to the late Indosinian, and on this basis, a dynamic model of Indosinian mineralization is proposed: the ancient Tethys ocean closure causes the Indosinian plate to collide with the Yangtze plate, and the strong regional tectonic events provide mineralization. The power has formed a basic rock of 218±3.2Ma in the Zhenfeng area. In addition, there may be some buried Indosinian granite intrusions in the area. These invading rocks can be used as heat sources to drive the leaching of ore-forming elements, which are mainly caused by atmospheric precipitation, forming a Carlin-type gold deposit in the Zhenfeng Shuiyindong area.