河南嵩县黄水庵碳酸岩脉型钼（铅）矿床地质特征及辉钼矿Re-Os同位素年龄

河南省嵩县黄水庵大型矿床是东秦岭地区典型的碳酸岩脉型钼（铅）矿床之一。钼矿体主要赋存于新太古界太华群变质岩内的石英-方解石碳酸岩脉中，呈脉状、似层状或透镜状产出。矿区内辉钼矿主要呈浸染状、薄膜状、团块状分布于石英-方解石碳酸岩脉中，主成矿期形成方铅矿-辉钼矿-石英-方解石的矿物组合。成矿围岩蚀变类型有钾长石化、硅化、黄铁矿化、萤石化、硬石膏化等。对8件辉钼矿样品进行了Re-Os同位素测年，测得其模式年龄为（210.9±3.8） Ma~（207.9±3.0） Ma，等时线年龄为（208.4±3.6） Ma，表明该矿床形成于晚三叠世。辉钼矿的w（Re）为（60.12~137.79）×10^-6，指示出成矿物质可能主要来源于地幔。该矿床的成矿作用发生于华北板块与扬子板块碰撞造山的后碰撞伸展阶段，在此阶段，秦岭造山带发生了伸展走滑作用，软流圈物质上涌诱发上覆富集岩石圈地幔发生低程度部分熔融，所形成的碳酸岩岩浆携带成矿物质沿NW-NWW向深断裂带上升，在合适的地段成岩成矿物质沉淀富集成矿。

Geological characteristics and molybdenite Re-Os isotopic dating of Huangshuian carbonatite vein-type Mo (Pb) deposit in Songxian County, Henan Province

The Huangshuian large-sized deposit in Songxian Country of Henan Province is one of the typical Mo (Pb) carbonatite vein-type deposits in the East Qinling molybdenum belt. The ore bodies that occur in the quartz-calcite carbonatite dykes hosted in the metamorphic rocks of the Taihua Group are veinlike, stratoid or lenticular in form. Molybdenite, as the main metallic mineral in the deposit, assumes laminated, disseminated and crumb mineralization types in the quartz-calcite carbonatite dykes. The particular mineral association of galena, molybdenum, quartz, calcite was formed in the main metallogenic phase. The main alterations of the wall rock include silicification, K-feldspathization, pyritization, fluoritization and anhydritization. Eight molybdenite-bearing samples were selected for precise Re-Os dating, which yielded model ages ranging from (210.9±3.8) Ma to (207.9±3.0) Ma and an isochron age of (208.4±3.6) Ma. The deposit was formed in the Late-Triassic. The Re content of molybdenite is (60.12~137.79)×10^-6, indicating that they were mainly derived from mantle sources. The deposit was formed in the extensional period of the post-collision orogenic process between North China and Yangtze cratons. At the extensional stage, the carbonate melt-solution that originated from the enriched mantle carried ore-forming metals such as molybdenum and lead upward along fractures and eventually precipitated in the suitable place to form ore deposit.