赣北石门寺“多位一体”钨铜矿床铅同位素特征  

Lead Isotopic Characteristics of Shimensi “Multi-Position in One” Tungsten Copper Deposit in Northern Jiangxi

作　　者：余振东 谭荣 项新葵 徐先宇 王天晨 YU Zhendong;TAN Rong;XIANG Xinkui;XU Xianyu;WANG Tianchen(The Third Geological Brigade of Jiangxi Geological Bureau,Jiujiang 332000,Jiangxi,China)

机构地区：[1]江西省地质局第三地质大队,江西九江332000

出　　处：《中国钨业》2021年第6期9-21,共13页China Tungsten Industry

基　　金：江西省科学技术厅国家科技奖后备培育项目(20203AEI91004)。

摘　　要：石门寺钨铜多金属矿是赣北地区近年探明的“多位一体”式超大型矿床,通过对矿床特征、围岩蚀变和铅同位素研究表明:石门寺矿床主要有三种矿化类型,分别为细脉浸染型、热液隐爆角砾岩型和石英大脉型,其中细脉浸染型资源量占95%以上。矿体主要赋存在晋宁期与燕山期岩体内外接触带,且以外接触带为主,为一期多阶段成岩成矿作用的产物。燕山期似斑状黑云母花岗岩、细粒黑云母花岗岩与成矿关系密切,是钨铜矿化的主要成矿母岩。矿床围岩蚀变主要为云英岩化和绢云母化(绢英岩化),蚀变过程属于水化脱钙过程,析出的钙与WO;结合形成白钨矿。燕山期花岗斑岩具较高放射成因铅,与具较高放射成因矿石铅组合一致,显示晚阶段矿化;似斑状黑云母花岗岩和细粒黑云母花岗岩有类似的高场强元素地球化学特征,如相似的Nb/Ta、Zr/Hf比值,暗示两者可能来自同一源区。Shimensi W-Cu polymetallic deposit is a “multi-position in one” super-large deposit discovered in northern Jiangxi. The study of the wall rock alteration and lead isotope of the deposit show that there are three main mineralization types in Shimensi deposit, namely, veinlet disseminated type, hydrothermal cryptoexplosive breccia type and quartz vein type, among which veinlet disseminated type accounts for more than 95%. Ore bodies mainly occur in the inner and outer contact zones of Jinning and Yanshan rock bodies. The outer contact zones are the main products of one-stage multi-stage diagenesis and mineralization. As the main ore-forming parent rock of tungsten-copper mineralization Yanshanian porphyritic biotite granite fine-grained biotite granite is closely related to mineralization. The alteration of the surrounding rock of the deposit is mainly dolomitization and sericitization(sericitization). The alteration process is categorized to be hydration and decalcification. The combination of precipitated calcium with WO;generate scheelite.Yanshanian granite porphyry has high radiogenic lead. Consistent with the lead assemblage of ore with high radiogenesis,it shows the feature of late mineralization. The porphyritic biotite-like granite and fine-grained biotite granite have similar geochemical characteristics of high-field elements, such as the similar Nb/Ta、Zr/Hf ratio, suggesting that they may come from the same source area.

关 键 词：石门寺钨铜矿床 多位一体 围岩蚀变 铅同位素 高场强元素 

分 类 号：P618.67[天文地球—矿床学] P618.41[天文地球—地质学]