Wula Mountains-Daqing Mountains, the important gold mineralization belts in the northern margin of the North China Block, host the large Hadamegou—Liubagou gold—molybdenum orefield, but ore—forming time and tectonic settings of the orefield are still in dispute and the orefield has long been considered the products of tectonic activity during the Mesozoic. Quartz vein-type and potassic alteration-type molybdenum mineralization paragenetic with gold was recently discovered at the depth of the Hadamengou gold deposit. Re-Os isotopic method in this study was employed to chronologically determine molybdenite paragenetic with Au-bearing pyrite. Four samples of molybdenite yielded an isochrone age of 386. 6 +6. 1 Ma ( MSWD = 1.18), with a weighted average of 386. 4 +2. 7 Ma (MSWD = 0. 55 )and an initial 187Os value of -0.02 + 0.41. Combined with other geological evidence, our result suggests that the gold mineralization event at the Hadamengou area could date back to the Early Devonian, which indicates an event of tectonomagmatic activity occurring in the early Hercynian period. The data acquired above are of important significance, both theortically and practically, in further understanding the gold mineralization and regional geological evolution of this area.%乌拉山--大青山成矿带为华北板块北缘重要的金成矿带,其中蕴含哈达门沟--柳坝沟大型金(钼)矿田,金(钼)矿床成矿时代和构造背景一直存在争议,长期被认为是中生代构造岩浆活动产物,最近在哈达门沟金矿床深部发现了与金共生的石英脉型和钾化蚀变岩型钼矿化,笔者等利用Re-Os同位素分析方法,首次对与含金黄铁矿共生的辉钼矿进行了年代学研究.4件辉钼矿Re-Os同位素等时线年龄为386.6±6.1 Ma(MSWD=1.18),加权平均年龄为386.4±2.7Ma(MSWD=0.55),初始(187)Os值为-0.02±0.41.根据以上年龄值,并且结合其它地质证据,可以推测,哈达门沟地区金矿化发生的事件可追溯到早泥盆世,属海西早期构造--岩浆活动事件.上述数据的取得,对重新认识该区金矿成矿作用及区域地质演化历史有着重要的理论和实际意义.
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