摘要
拉尔玛金矿床及其附近铀矿床的U-Th-Pb年龄、载金石英40Ar/39Ar年龄和其它同位素年龄表明,金铀成矿热液活动有两个阶段:第一阶段>137Ma;第二阶段41～60Ma,为金矿化主期,具有卡林型金矿床后生成矿的特征。Ph同位素组成显示矿区存在5个铅源,即含矿地层沉积岩(非铀矿化正常Pb)、中生代岩浆岩(正常Pb)以及三种铀矿石(高Pb同位素比值异常Pb)。金矿床内沉积岩、长英质脉岩及蚀变矿物具有至少三端员或四端员Pb同位素混合组分。成矿热液的Pb同位素组成受控于非铀矿化沉积岩、铀矿石和长英质脉岩以及水/岩反应。成矿物质主要来源于太阳顶群及邻近的铀矿化岩石。
U-Th-Pb dating of the La' erma gold deposit and its adjacent uranium deposit as well as 40Ar/39Ar dating of gold-bearing quartz veins in west Qinling Mt. show two stages of gold-uranium mineralization in the study area happened at 137 Ma and 41 ~60Ma, respectively. The main gold mineralization(epigenetic metallization) occurred during the second stage. There are five lead isotope compositions in the study ore district, including normal lead of the host strata with no uranium mineralization and normal lead of the Mesozoic igneous rocks as well as three kinds of abnormal lead related to uranium mineralization. AH the sedimentary rocks, felsic veins and altered minerals in this district show multiple source of lead isotope composition, which suggests the lead isotope composition of mineralizing solution be controlled by sedimentary rocks with no uranium mineralization, uranium ores, felsic veins and water/rock reaction, and ore-forming metallic elements originated mainly from the Taiyangding Group and adjacent rock suit with uranium mineralization.
出处
《华南地质与矿产》
CAS
1997年第4期39-49,共11页
Geology and Mineral Resources of South China
