特提斯构造域碰撞造山型金矿成矿机制

Tethyan tectonic domain is the least studied one in the three biggest metallogenic domains in the world. In addition, the wellknown orogenic gold deposit model was proposed mainly based on extensive studies on shear zone hosted gold deposits in Precambrian metamorphic terrains. Most of previous researchers thought that orogenic gold deposits mainly occur in accreted terrains, and collisional orogenic belts are not in favor of gold mineralization. But in recent years, a lot of Cenozoic orogenic gold deposits were discovered in Tethys collisional orogenic belts, such as Zagros orogen in Iran, Au-Sb belt in South Tibet, Ailaoshan gold belt in Yunnan Province and W. Sichun gold belts. In this study, based on international cooperation and comparative investigation, we will focus continental collision, late collisional tectonic transformation and post collisional crustal extension and related gold mineralization, investigate the detailed deformation process of the shear zone and its relationship with gold enrichment, crust/mantle interaction and vertical material exchange, metallogenic periods and mechanism of the large-scale gold deposit, to explore gold enrichment mechanism during various evolution stages, and establish a new orogenic gold deposit model under continental collisional environment. Results of this study will be helpful for establishment of a new gold metallogenic model in continental collision and exploration of gold in the Tethyan tectonic domain, and also be helpful for the exploration of the key scientific problem three in this major research plan: Mineral and energy resource response to the one-way splitting and matching processes of multiple continental blocks.

世界三大成矿域中，特提斯成矿域研究程度最低。此外，国际上流行的造山型金矿理论主要是在前寒武克拉通剪切带型金矿基础上发展起来的,一般认为造山型金矿主要发育在增生造山带，而碰撞造山不利于成矿。但在特提斯成矿域，喜马拉雅期造山型金矿大量发育，如伊朗Zagros造山带、藏南金锑成矿带、云南哀牢山和川西金矿带等。本项目拟以国际合作方式, 围绕特提斯构造域主碰撞陆陆汇聚、晚碰撞构造转换和后碰撞地壳伸展三大关键地质过程及相应的金成矿系统开展研究，特别是研究构造变形的详细过程与金矿化耦合关系、壳/幔相互作用和纵向物质交换与金富集机制、金成矿年代与成矿机理等，以揭示该区构造演化不同阶段中金矿成矿过程和机理，建立陆陆碰撞条件下造山型金矿成矿模式。本项目的研究将有望建立碰撞造山背景下新的金成矿理论, 有力指导该区金矿勘探，有助于本重大研究计划的关键科学问题之三“多陆块单向裂解-聚合过程的资源能源响应”的解决。

世界三大成矿域中，特提斯成矿域研究程度最低。此外，国际上流行的造山型金矿理论主.要是在前寒武克拉通剪切带型金矿基础上发展起来的,一般认为造山型金矿主要发育在增生造山带，而碰撞造山不利于成矿。但在特提斯成矿域，喜马拉雅期造山型金矿大量发育，如伊朗Zagros造山带、藏南金锑成矿带、云南哀牢山和川西金矿带等。本项目以国际合作方式, 围绕特提斯构造域主碰撞陆陆汇聚、晚碰撞构造转换和后碰撞地壳伸展三大关键地质过程及相应的金成矿系统开展研究，特别是研究构造变形的详细过程与金矿化耦合关系、壳/幔相互作用和纵向物质交换与金富集机制、金成矿年代与成矿机理等，以揭示该区构造演化不同阶段中金矿成矿过程和机理，建立陆陆碰撞条件下造山型金矿成矿模式。本项目取得如下主要进展: 1. 对藏南与伊朗扎格罗斯碰撞造山带造山型金矿对比研究, 发现不同的陆陆碰撞角度和岩石圈组成是藏南和扎格罗斯Sanandaj-Sirjan变质带造山型金矿成矿差异的主要原因; 2.对藏南造山型Au和Au-Sb矿进行了热液副矿物LA-ICP-MS U-Pb原位精确定年, 确定热液副矿物(磷灰石、金红石、石榴石、独居石、方解石、铁氧化物等）原位U-Pb定年是厘定造山型金矿成矿年代快速有效的方法; 3.相对伊朗高原, 多期造山和较快隆升剥蚀是青藏高原金矿相对稀少的主要原因; 4.下地壳高压相变质岩硫化物可能是藏南造山型金矿中金的主要来源之一。韧性剪切破坏下地壳中硫化物，释放出的Au、S和CO2 沿剪切带到达韧脆性转换带，形成造山型金矿. 本项目的研究将深化我们对碰撞造山背景下金成矿机制, 指导青藏高原金矿勘探，并有助于本重大研究计划的关键科学问题之三“多陆块单向裂解-聚合过程的资源能源响应”的解决。本项目共完成论文17篇, 先后培养了1名博士后和 6名博士生.