Cassiterite U-Pb Date of the Yangbin Porphyry Tin Deposit in Zhejiang and its Geological Significance

Objective The Yangbin porphyry tin deposit in Taishun County of Zhejiang Province is one of the few porphyry-type tin deposits in South China, which is located in the middle portion of the Mesozoic volcanic active belt on the southeastern coast of China. The Yangbin granite porphyry is closely related to the tin mineralization in this region. Based on petrologic and Sr-Nd-Pb isotopic

浙江洋滨黄玉花岗斑岩的Nd、Sr、Pb同位素研究

洋滨斑岩锡矿位于我国东南沿海中生代火山活动带中部．含矿岩石主要由青黄玉的钾长花岗斑岩与二长花岗斑岩及黄英斑岩组成．这些岩石具有高硅、强过铝质、富集不相容元素、弱的铈和强的铕负异常以及高的稀土总量等特征．采用最小二乘法计算的全岩Ｒｂ－Ｓｒ等时线年龄为１０１．７±２．１Ｍａ，（８７Ｓｒ／８６Ｓｒ）ｉ＝０．７１４２±９．同时，它们具有低的εＮｄ值（－８．４～－８．０），较高的２０７Ｐｂ／２０４Ｐｂ（１５．５８８～１５．６６６）以及较古老的二阶段Ｎｄ模式年龄（１５９７～１７４３）Ｍａ．这些特征表明，洋滨花岗斑岩的母岩浆属于Ｓ型，它们可能是由本区未出露的中元古代变质沉积岩经部分熔融方式形成．初始岩浆经历了强烈的分离结晶，继之以流体岩浆／分离过程。