安徽青阳百丈岩钨钼矿床成岩成矿年龄测定及地质意义

Rock-forming and ore-forming ages of the Baizhangyan tungsten-molybdenum ore deposit in Qingyang,Anhui Province and their geological significance.

百丈岩钨钼矿床是在老矿点基础上新查明的中型层控夕卡岩型钨钼矿床。文中对含矿岩体和矿石进行了成岩成矿年龄测定,获得百丈岩细粒花岗岩锆石SHRIMP U-Pb年龄为(130±1.5)Ma(n=14,MSWD=0.69),浸染状辉钼矿Re-Os同位素等时线年龄为(136.3±2.6)Ma(n=5,MSWD=0.64),模式年龄为(133.5±1.9)～(135.6±2.0)Ma。综合区域最新获得的高精度测年数据分析,结果表明,百丈岩钨钼矿床形成于早白垩世,和与之有密切成因关系的花岗岩体成岩是同期的,属于燕山晚期陆壳重熔型花岗质岩浆侵位的产物。

Baizhangyan tungsten-molybdenum ore deposit is a newly developed deposit which was found on the base of a small exposure of mineralization occurrence.With highly precise dating of the ages of the rock-forming and ore-forming,the authors obtained a SHRIMP U-Pb zircon age of（130±1.5）Ma（n=14,MSWD= 0.69）for fine-grained granite and Re-Os model ages of（133.5±1.9）-（135.6±2.0）Ma and isochron age of （136.3±2.6）Ma（n=5,MSWD=0.64）.According to the ages above,the authors concluded that the deposit was formed in the Early Cretaceous;that it was the result of intrusions of the granite which was of crust-source remelting type.The ore-forming age is similar to the rock-forming age of the granite rock body that was important to the deposit.