摘要:天山—兴蒙钼矿带是中亚成矿域的重要组成部分，该成矿带主要呈近东西向分布；本文通过对天山—兴蒙钼矿带4个典型矿床Re-Os同位素精确定年，结合前人区域动力学背景的研究，揭示天山—兴蒙造山带钼矿床的成矿作用主要与岩浆侵入形成的花岗岩热液作用有关，并识别出兴蒙造山带3期岩浆活动、钼成矿作用和构造热事件；Re-Os定年结果揭示出晚古生代铜—钼矿床与俯冲—增生作用有关，三叠纪钼的成矿形成于西伯利亚板块与塔里木—华北克拉通碰撞背景下，而侏罗纪—早白垩世的钼成矿作用与古太平洋板块西向俯冲作用有关。
关键词: Re-Os定年/
钼矿床/
构造背景/
天山—兴蒙造山带/
中亚
Abstract:The Tianshan-Xingmeng molybdenum belt is part of a larger E-W trending metallogenic belt in northern China. Most of the molybdenum deposits occur as porphyry or porphyry-skarn type, but there are also some vein type deposits. Following systematic Re-Os dating of molybdenite from 4 deposits and comparisons with two previously dated deposits, we have inferred that the molybdenum mineralization in the Tianshan-Xingmeng orogenic belt was developed during hydrothermal activity linked to magmatism and the emplacement of granitoid stocks. Three pulses of granitoid magmatism and Mo mineralization have been recognized in this study, corresponding to significant tectonic events in the Tianshan-Xingmeng orogenic belt. Our results show that the Late Paleozoic Cu-Mo deposits are closely related to subduction-accretion generated lithosphere processes, whereas the Triassic Mo deposits probably formed in a syn-collision setting between the Siberian and Tarim-North China Cratons. Similarly, the Jurassic-Early Cretaceous Mo deposits are most likely related to tectonic and magmatic events resulting from the westward subduction of the palaeo-Pacific plate.
Key words:Re-Os dating/
Molybdenum deposits/
Tectonic setting/
Tianshan-Xingmeng orogenic belt/
Central Asia
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