西藏冈底斯东段南缘桑布加拉辉钼矿Re-Os定年及地质意义

雅鲁藏布江缝合带北侧的桑布加拉矽卡岩型铜矿床为冈底斯成矿带南亚带典型多金属矿床之一。该矿床的8件辉钼矿样品Re-Os等时线年龄为（93.3±4.1）Ma，平均模式年龄为（94.5±1.6）Ma，表明桑布加拉矿床形成于晚白垩世新特提斯洋向北俯冲消减阶段。洋壳俯冲消减阶段形成的桑布加拉铜矿床及其新生代不同时期多金属矿床的发现，说明冈底斯成矿带在俯冲消减阶段、主碰撞阶段、晚碰撞阶段和后碰撞阶段均存在大规模成矿作用，并构成完整的成矿演化系列。 

MOLYBDENITE Re-Os ISOTOPIC DATING OF SANGBUJIALA COPPER DEPOSIT IN THE SOUTH MARGIN OF THE EASTERN GANGDESE SECTION,TIBET,AND ITS GEOLOGICAL IMPLICATIONS

Located in north side of Yaluzangbujiang Suture, Sangbujiala skarn-type copper deposit is one of the typical polymetaUic deposits in the south subzone of the Gangdese metallogenic belt. For the purpose of finding out the mineralization time, the authors selected eight molybdenite samples from Sangbujiala ore district to perform the Re-Os dating. The age of Re-Os isotime line from molybdenite is 93.3 ~4. 1 Ma, with an average model age of 94.5 ~ 1.6 Ma. Therefore, the Sangbujiala ore formed during Late Cretaceous, which belongs to the Neo-Tethys subduction stage. The Sangbujiala ore and other Cenozoic deposits showed that the Gangdese metallogenic belt occurring large-scale mineralization in the subduction stage, main collision stage, late collision stage and post-collisional stage, and to form a complete series of metallogenie evolution.