东南亚特提斯构造岩浆演化与锡钨成矿响应

Southeast Asia lies in the easternmost part of Tethyan tectonic domain, and has multiple-stage tectonic evolution. Southeast Asia contains abundant mineral resources, in particular its tin-tungsten metallogenic belt is one of the most important Sn-W producers in the world. However, the studies on Mesozoic granites and related Sn-W deposits in Southeast Asia is relatively rare and many basic geological problems remain unsolved. In this project, we will focus on the following three key scientific problems that urgently need to be solved: (1) Temporal and spatial distribution, petrogenesis of Mesozoic granites in Southeast Asia and their implications for Tethyan tectonic evolution; (2) Petrogenesis of ore-bearing granites and relationship with Sn-W mineralization; (3) Regional Sn-W mineralization rules and ore geneses. We will carry out detailed field investigation on both granites and ore deposits on the Southeast Asia tin-tungsten metallogenic belt, and apply state-of-art geochronologic, geochemical and multiple-isotopic methods, to constrain the temporal and spatial distribution of Mesozoic granites and Sn-W deposits, to elucidate the petrogenesis and relationship with Sn-W mineralization of different-age, different-type granites, to reveal the Sn-W mineralization process and ore genesis. The expected results of this project will not only provide a particular angle of deeply understanding the whole Tethyan tectonic evolution and its response for formation of mineral resources, but also provide technical support for developing collaborative research on mineral resources with Southeast Asia countries and carrying out national “One Belt and One Road” development strategy.

东南亚地处特提斯构造域最东端，经历了多期次的构造演化，矿产资源丰富，特别是锡钨成矿带是世界上最重要的锡钨矿产地之一。但目前对东南亚广泛发育的中生代花岗岩及锡钨矿床的整体研究程度较低，研究基础薄弱。本项目拟围绕本区亟待解决的如下三个关键科学问题：（1）东南亚中生代花岗岩的时空分布、岩石成因及对特提斯构造演化的指示；（2）含矿花岗岩的成因及与锡钨成矿作用的关系；（3）东南亚锡钨矿床成矿规律与矿床成因，针对东南亚锡钨成矿带上典型的岩体和矿床开展地质调查，采用先进的成岩成矿年代学、岩石地球化学和矿床地球化学，以及多种同位素地球化学示踪方法，查明岩体和矿床的时空分布规律，阐明不同时代、不同类型花岗岩的成因及与锡钨成矿作用的关系，揭示特提斯构造演化对该区成岩成矿的控制作用。项目成果将会深化对整个特提斯构造演化及资源响应的认识，同时可为开展东南亚矿产资源合作研究、实施“一带一路”国家战略提供支撑。

东南亚地处特提斯构造与最东端，经历了多期次的构造演化，矿产资源丰富，特别是锡钨成矿带是世界上最重要的锡钨产地。通过对东南亚锡矿带（缅甸、泰国、老挝、马来西亚）上的主要花岗岩和典型矿床开展成岩成矿年代学的研究，特别是采用矿石矿物（锡石和黑钨矿）原位U-Pb同位素定年新方法确定了主要原生锡钨矿床的成矿时代，厘清了东南亚锡矿带花岗岩和矿床的时空分布规律。东南亚锡矿带西区（缅甸境内和泰国西南部）花岗岩主要形成于105-42 Ma，对应的锡钨成矿作用也主要发生在90-85 Ma，70-60 Ma，50-42 Ma期间。锡矿带上的花岗岩与西边的Wuntho-Popa弧上的岩浆岩形成时代一致，但岩石地球化学和同位素特征指示两边岩浆岩的源区和成因类型完全不同。锡矿带上的花岗岩主要为S型花岗岩，全岩εNd（t）值为-14~-10，来源自成熟地壳物质的部分熔融，并无地幔物质的加入。锡钨花岗岩与弧岩浆岩构成了两条平行的、形成时代一致的、但源区不一样的岩浆岩带。因此，该区花岗岩和锡钨矿化主要形成于新特提斯洋俯冲所导致的弧后伸展环境。东南亚锡矿带东区（马来西亚东部）花岗岩和锡钨成矿作用位于文冬-劳务缝合带以东，主要形成于289-220 Ma间，且从东往西有变年轻的趋势，应主要形成于古特提斯洋俯冲所导致的弧后伸展环境。而东南亚锡矿带主区（泰国境内和马来西亚西部）花岗岩和成矿作用位于文冬-劳务缝合带以西，主要形成于226-200 Ma间，应形成于古特提斯洋闭合（约230 Ma）之后的后碰撞伸展阶段。因此，东南亚锡矿带上的原生锡钨矿床主要形成于古特提斯和新特提斯构造演化的俯冲阶段和后碰撞阶段。本项目研究通过东南亚锡矿带花岗岩和锡钨矿床的时空分布规律，结合对成岩成矿作用的研究，深入揭示了东南亚锡矿带成岩成矿作用发生的构造动力学背景，回答了本项目研究任务中特提斯构造岩浆演化及锡钨成矿响应的核心科学问题，对于完善锡钨矿床成矿理论具有重要意义。