论文部分内容阅读
冷水坑矿田位于北武夷隆起北缘。在简要介绍该矿田地质特征基础上,通过锆石SHRIMP U-Pb法测年,获得了矿田内赋存火山沉积热液改造型银铅锌矿体的打鼓顶组凝灰岩加权平均年龄(157.6±3.2)Ma,表明打鼓顶组火山岩形成于晚侏罗世。该年龄可以代表成矿作用的下限年龄,并说明矿田推覆构造的活动时间与晚侏罗世火山活动的时间基本一致。推覆构造的发育说明中国东部构造体制已经从近东西向的特提斯构造域转换为北北东向的滨太平洋构造域。晚侏罗世火山活动及推覆构造的发育是Izanagi板块沿北西方向向欧亚板块之下俯冲所产生的结果。
Lengshuikeng ore field is located in northern edge of North Wuyi uplift. Based on the geologic characteristics of the orefield, the weighted average age of tuff in the Dajinking Formation of the volcanic sedimentary hydrothermally modified Ag-Pb-Zn ore body within the orefield was obtained by zircon SHRIMP U-Pb dating (157.6 ± 3.2) Ma, indicating that the Dajutou volcanic rocks were formed in the Late Jurassic. This age can represent the minimum age of mineralization and indicate that the activity time of the nappe structure in the ore field is basically consistent with that of the Late Jurassic volcanic activity. The development of the nappe structure indicates that the structural system of the eastern China has been transformed from the near-east-west Tethys tectonics to the north-easterly foreshore Pacific tectonic domain. Late Jurassic volcanic activities and the development of nappe structures are the result of subduction of the Izanagi plate beneath the Eurasian plate in the NW direction.