西南三江昌宁—孟连缝合带复合造山演化与成矿系统时空结构

The Changning-Menglian suture zone of the Sanjiang Tethyan region has experienced firstly the accretionary orogenesis, which comprises Proto- and Paleo-Tethyan evolution, and secondly the Cenozoic continental collisional orogenesis, resulting in the composite orogeny at the same space. During composite orogeny, ore deposits with a variety of genetic types formed in different tectonic backgrounds. The project focuses on two key scientific issues, i.e., composite orogenic evolution and deep drive and the space-time structure of metallogenic system. Based on the geological and geochemical analysis on the important records, including the Paleozoic to Mesozoic ophiolitic components, eclogites, picrites, A-type granites, mafic-intermediate rocks, and the clastic rocks resulted from orogenic sedimentation, the project plan to reveal the spatio-temporal evolution of Changning-Menglian Proto- and Paleo-Tethyan evolutions. According to the Cenozoic magmatic rocks and regional geophysical data, it aims to reveal the Cenozoic evolution. Then a dynamic model for the composite orogeny in Changning-Menglian suture zone will be established. The other important aspect of this project is to research the ore-forming material and fluid source, transportation and physicochemical conditions, as well as the metallogenic processes and metal precipitation mechanisms of different types of deposits by means of analysis on in-situ fluid inclusions, mineral trace elements and multiple isotopes. The ultimate target is to clarify the links between the mantle metasomatism, mantle-crust interaction, crustal deformation and metamorphism process, and magmatic-hydrothermal evolution to understand the multi-level deep driving and coupling mechanism for metallogeny in composite orogeny.

西南三江特提斯昌宁—孟连缝合带依次经历了由原—古特提斯旋回构成的增生造山和印度 —欧亚陆陆碰撞造山两个阶段；复合造山作用形成不同构造背景内的多种成因类型矿床。项目围绕复合造山演化过程与深部动力学驱动、复合造山成矿系统时空结构与典型矿床成因两大关 键问题，通过对缝合带及两侧古—中生代蛇绿岩套、榴辉岩、苦橄岩、A型花岗岩、中基性岩和碎屑岩等岩石组合的地质地球化学特征分析，揭示原—古特提斯演化过程与构造体制转换事件；通过对新生代岩浆岩解析，阐明复合造山带新生代壳幔结构和改造特征。借助原位流体包裹体、矿物微量元素、多元同位素等手段分析不同成因类型矿床成矿物质和流体来源、输运和金属积淀过程及其物化条件揭示成矿机理。综合阐释复合造山成矿系统的地幔改造—壳幔作用—岩浆与流体演化的多层次深部驱动机制和多因耦合成矿机理。

聚焦复合造山演化过程与深部动力学驱动、复合造山成矿系统时空结构与典型矿床成因两大关键问题，以昌宁-孟连造山带为主要研究对象，对比金沙江-哀牢山造山带以及兰坪-思茅盆地，针对原-古特提斯构造演化与成矿系统，碰撞造山构造过程及其对增生造山的复合效应，复合造山成矿系统时空结构与就位机制开展研究，取得如下主要成果。.1. 厘定了原特提斯VMS型Cu-Zn-Au成矿系统，建立了成矿过程中磁性矿物演化模式；识别出保山地块早古生代矽卡岩型Fe-Zn-Pb成矿作用，建立了原特提斯岩浆-热液型成矿系统；构建了原特提斯构造演化与成矿模式，提出保山地块与冈瓦纳大陆碰撞后的伸展环境形成VMS和矽卡岩型成矿作用。.2. 构建了古特提斯VMS成矿系统；探讨了三叠纪临沧花岗岩锡成矿作用与成矿潜力，提出部分三叠纪含锡花岗岩中的锡矿化可能与隐伏的晚期花岗岩有关；查明了三叠纪火山岩中热液脉状铜矿成因类型，认为兰坪-思茅地块新生代逆冲推覆驱动盆地流体与三叠纪火山弧发生水岩反应并形成脉状铜矿。.3. 查明了昌宁-孟连造山带新生代成矿系统时空就位机制，提出了昌宁-孟连造山带东侧景谷矿集区与兰坪盆地金顶矿集区发生显著的地壳差异旋转，地壳差异旋转与成矿时间一致（~27 Ma），提出地壳差异旋转引发了壳幔变形多层解耦和成矿作用并控制了矿集区就位。.4. 提出了前期大洋俯冲-增生造山形成富集地幔、新生下地壳以及富金属上地壳岩系，后期大陆碰撞促使上述改造或新生单元金属活化分别形成造山型金矿与碳酸岩稀土矿、斑岩-矽卡岩型铜钼金、MVT铅锌矿与热液型锗矿；揭示出增生造山过程的物质循环为成矿奠定基础，碰撞造山的物质活化是成矿的直接诱因，而复合造山则是区域巨量金属富集和大型矿产资源形成的驱动。.发表第一标注国际SCI论文13篇，包括Geology（高被引论文），Earth-Science Reviews，Journal of Geophysical Research: Solid Earth，Mineralium Deposita, Gondwana Research等期刊。培养博士生6人。项目负责人获得李四光地质科学奖（2019），入选美国经济地质学会会士（2020），当选中国科学院院士（2021）；项目成员分别获国家杰青（2021）、国家青年拔尖人才（2022）、国家自然科学基金重点项目（2022）。