Located in the northeastern Zijinshan ore field, the Luoboling Cu-Mo deposit is a large -scale porphyry deposit hosted by the Sifang granodiorite and Luoboling granodiorite porphyry. Re-Os dating of eleven molybdenite separates collected from different depths of ore bodies in the Luoboling Cu-Mo deposit shows that the isochron age is 104. 9 + 1. 6 Ma and the model ages ranging from 104. 7?. 6 Ma to 106. 5?. 5 Ma, with an average age of 105. 64?. 46 Ma. It indicates that the Luoboling Cu-Mo deposit formed in Early Cretaceous, consistent with the emplacement age of the host rocks, and that the magmatism and mineralization took place under the same geological setting. Since the Zijinshan ore field is composed of several porphyry and epithermal deposits, it is suggested that the ore fluid evolution of Zijinshan ore field may started from 105 Ma, when the Luoboling porphyry Cu-Mo deposit formed.%罗卜岭铜钼矿床是位于紫金山矿田北东侧的一个大型斑岩型铜钼矿床,铜钼矿体产于四方花岗闪长岩和罗卜岭花岗闪长斑岩体内.通过对该矿床11件代表性辉钼矿样品进行Re-Os同位素定年,获得的模式年龄为104.7±1.6～106.5±1.5 Ma,等时线年龄为104.9±1.6 Ma,与赋矿围岩的成岩年龄一致,表明罗卜岭铜钼矿床形成于早白垩世,属燕山晚期构造—岩浆活动产物.由于斑岩铜钼矿床为紫金山矿田成矿流体早期演化的产物,故认为紫金山矿田成矿流体演化起始于105Ma左右.
展开▼
