东秦岭寨凹钼矿床辉钼矿Re-Os同位素年龄及熊耳期成矿事件

Molybdenite Re-Os isotope age of the Zhaiwa Mo deposit and implications for Xiongerian mineralization in eastern Qinling Orogen

河南寨凹钼矿床位于东秦岭钼矿带,是近年来新发现的脉状钼矿床。9件辉钼矿样品Re-Os模式年龄介于1603.1±10.8～2031.9±10.2Ma,其中7件样品给出了精确的等时线年龄为1762±31Ma(1σ误差,MSWD=3.6),模式年龄的加权平均值为1753±26Ma(1σ误差,MSWD=3.2),表明寨凹钼矿形成于古元古代或熊耳期,代表着～1.76Ga左右的钼成矿事件。根据区域地质演化,认为寨凹钼矿形成于与熊耳群弧火山岩建造相当的活动大陆边缘岩浆弧背景。寨凹矿床的发现表明,熊耳期成矿事件虽遭受后期多次增生和碰撞造山作用的改造和破坏,但仍可在秦岭造山带最北部保留。

The Zhaiwa Mo deposit occurs in the southern margin of the North China craton.This deposit was interpreted as an intrusion-related vein/lode type in previous study.Nine molybdenite samples from the deposit yield Re-Os isotopic model ages ranging from 1603.1±10.8～2031.9±10.2Ms with an average age of 1753±26Ms(1σ,MSWD=3.2) and give an isochron age of 1762±31Ms(1σ,MSWD=3.6).These ages imply the first discovery of～1.76Ga Mo mineralization in the eastern Qinling Orogen and China.On the basis of geological evolut...