摘要
镰子沟金矿床位于小秦岭金矿集区西部,矿体受断裂和石英脉体控制,围岩蚀变以钾化和硅化为主。矿床浅部以金矿为主,深部发现金钼(共)伴生矿体。为了确定镰子沟金矿床成岩、成矿时代,选择镰子沟金矿床正长斑岩和金钼矿石分别进行了LA-ICP-MS锆石U-Pb和辉钼矿Re-Os同位素研究。获得正长斑岩的207Pb/206Pb年龄加权平均值为1802.9±9.9Ma,此年龄明显早于小秦岭地区金矿床的形成时代;获得辉钼矿Re-Os等时线年龄为128.8±6.5Ma,指示矿床形成于早白垩世,晚于区域已知花岗岩形成时代。综合研究认为,镰子沟金矿床的形成与区域花岗岩无关,可能与深部流体或隐伏岩浆有关。
The Lianzigou gold deposit is located in the west of Xiaoqinling Au ore concentration area. The orebodies are hosted in the upper strata of Taihua Group and controlled by fault fracture zone or quartz veins. The wall rock alteration is dominated by potassium alteration and silicification. Au(Mo) orebodies have been discovered in the depth of the deposit. To constrain its petrogenic and metallgogenic ages, the authors carried out LA-ICP-MS zircon U-Pb dating on syenite porphyry and Re-Os dating on molybdenite, respectively. LA-ICP-MS zircon U-Pb dating of syenite porphyry gave a weighted average age of 1802.9±9.9 Ma,which is clearly older than the age of large-scale gold mineralization in the Xiaoqinling area. Re-Os dating on molybdenite from the Au orebodies gave an isochron age of 128.8±6.5 Ma, indicating that the Au and Mo mineralization occurred in Early Cretaceous. The Re-Os age is younger than the petrogenic ages of granites in the Xiaoqinling area, showing that there is no direct relationship between the known granitic magmatism and the mineralization of the Lianzigou Au deposit. Deep fluids or concealed magmatic intrusion probably played an important role in mineralization.
作者
代军治
高菊生
钱壮志
王渊
周金隆
高毅
DAI Junzhi;GAO Jusheng;QIAN Zhuangzhi;WANG Yuan;ZHOU Jinlong;GAO Yi(Northwest Geological and Mining Group Co., Ltd., for Nonferrous Metals, Xi'an 710054, Shaanxi,China;Chang’an University, Xi'an 710054, Shaanxi, China;No. 712 General Party Co., Ltd., of Northwest Mining and Geology for Nonferrous Metals, Xianyang 712000, Shaanxi, China)
出处
《地质通报》
CAS
CSCD
北大核心
2019年第8期1369-1377,共9页
Geological Bulletin of China
基金
西北有色地质矿业集团博士后项目《金堆城外围金、钼矿床成矿特征与找矿预测研究》(编号:西色地发[2016]46号)