【摘要】 位于华北克拉通南缘东秦岭钼矿带的南泥湖为一超大型夕卡岩—斑岩型钼(钨)矿田,本研究采用电感耦合等离子体质谱仪法对南泥湖钼矿田三个矿床6件辉钼矿进行了Re-Os同位素年龄测定,获得南泥湖矿床的辉钼矿Re-Os模式年龄为141.8±2.1 Ma;三道庄矿床的辉钼矿Re-Os模式年龄为144.5±2.2～145.0±2.2Ma,平均为145.0±2.2 Ma;上房沟矿床的辉钼矿Re-Os模式年龄为143.8±2.1～145.8±2.1 Ma,平均为144.8±2.1 Ma;6件样品的等时线年龄为141.5±7.8 Ma(2σ),准确厘定了成矿时间。Re-Os同位素还表明:南泥湖钼矿的成矿物质来源以下地壳成分为主,但混有少量地幔组分。南泥湖钼矿是在中国东部中生代构造体制大转换中形成,属于中国东部中生代大规模成矿作用的一部分。更多还原

【Abstract】 Nannihu orefield, including Nannihu, sandaozhuang, Shangfanggou deposits and so on, is a large-scale skarn and/or porphry type of Mo(W) orefield,occurred in the Eastern Qinling metallogenic belt in southern margin of the North China craton. In this paper, the contends of 187Re and 187Os of molybdenite from the molybdenum (tungsten) deposits are determined by inductively coupled plasma mass sperctrometry (ICP-MS) , With analytical errors of Re and Os between 0. 11%~0. 4% (2σ). The results obtained show that the Re-Os model ages of deposits are between 145. 8 ±2.1-141.8 ±2.1 Ma; 141.8±2.1 Ma for the Nannihu deposit; 145. 4 ±2. 0~144. 5±2. 2Ma(average: 145. 0±2.2Ma ) for Shandaozhuang deposit and 145.8±2.1~143. 8±2.1Ma(average; 144. 8±2.1Ma) for Shangfanggou deposit. Precise Re-Os isotopic dating for the molybdenite in the deposits yields an isochron age of 141. 5±.7.8Ma(2σ),with errors of Re-Os ages between 2. 0%~2. 2%. The results suggest that the ore-forming materials mainly derived from the crust and was mixed with the component of the mantle. The Nannihu molybdenum (tungsten) orefield, which formed when the tectonic transformation predominated, is a component part of the large-scale mineralization in late Mesozoic in eastern China.更多还原