胶东金矿中生代成矿作用

The Jiaodong area is the most important gold province in China. This area experienced tectonic regime superposition/transition of continental collision and oceanic plate subduction in Mesozoic, and extensive gold mineralization occurred during this period. However, the metallogenic regulation still needs more work. This project is guided by the theory of metallogenic system, using the ideas of comparative metallogeny and "ore deposit probe", and the methods and techniques of multiple disciplinary intersections and merging. The critical scientific topics are mainly focused on the timing of gold mineralizaion and its kinetic background, ore-forming processes and mechanism of gold enrichment. The ore deposits that we will study include Jiaojia, Linglong, Sanshandao, Rushan, Dyingezhuang and Majiayao gold deposits. The main research contents are as follows: ore-hosted formation-ore-controlling structures and tectonic-magmatic associations, accurate dating of gold mineralization and reconstruction of thermal history, gold-bearing minerals and in-situ analysis of fluid inclusion assemblage, combined refutation of metallogenic thermomechanics and hydrokinetics, comparing with typical orogenic gold deposits and other contemporary deposits. The aims of the project are to determine the timing sequence of tectonic-magmatic-metallogenic events and their dynamic backgrounds, to trace the origin of extensive gold and ore fluids, to constrain the gold transport-cluster processes and mechanism of gold enrichment, to illuminate the genetic association between tectonic regime superposition/transition and gold metallogeny, to reveal the gold deposits evolution/ occurrence regulations under complex tectonic background, and to provide scientific basis for the regional exploration.

胶东是我国最重要的金矿集区，中生代经历了陆陆碰撞造山和大洋板块俯冲构造体制的叠加/转换，发生了多幕式的大规模金成矿作用。然逼近客观实际的成矿规律尚未被揭示，亟需深入研究。项目以成矿系统理论为指导，运用比较矿床学和"矿床探针"的思路及多学科交叉融合的方法技术，针对金成矿作用时序及其动力学背景、叠加成矿过程与金超量富集机制两个关键科学问题，选取焦家、玲珑、三山岛等金矿床，通过赋矿建造-控矿构造和构造-岩浆组合研究、金成矿年龄精测与热历史重建、载金矿物与包裹体原位-组合分析、成矿热力学和流体动力学联合反演，并与典型造山型金矿床及其他同时代矿床对比，厘定构造-岩浆-成矿热事件时序与动力学背景，示踪巨量金和流体的来源，综合约束金的运移-集聚过程和超量富集机制，阐明构造体制叠加/转换过程与金成矿作用的成因关联，揭示复杂构造背景下金矿床的演化/赋存规律，为实现区域找矿新突破提供科学依据。

聚焦金成矿作用时序及其动力学背景、成矿过程与金超量富集机制两个关键科学问题，明确胶东金矿时空分布与成矿背景，剖析成矿特征与主控矿因素，厘定成矿流体与成矿物质来源，构建成因模式与勘查模型，获得如下主要成果。.1.提出胶东金矿是多元构造体制转换最佳耦合的产物。证实胶东中生代至少存在两次连续却明显不同金成矿事件，其均形成于伸展拆离向汇聚挤压转换构造体制，区别于典型造山型金矿形成的俯冲挤压构造背景和碰撞造山后挤压向伸展转换构造环境，对揭示区域构造演化和成矿规律奠定理论基础。.2.构建变质核杂岩与菱形格状断裂系控矿模式。查明金矿床赋存规律，指出区内金矿床赋存于菱形格状断裂系；识别出玲珑变质核杂岩控矿构造样式，揭示其形成-演化全过程，指出胶东金矿床形成于主拆离断层韧-脆性递进构造变形过程中，为构建矿床成因模式提供理论支撑。.3.揭示成矿物质最可能来源于俯冲板片及其上覆沉积岩中富金黄铁矿。指出胶东金矿床Au的富集约99%来自可见金，不可能来自黄铁矿内不可见金的活化；提出巨量金主体来源于再循环地壳物质并有富集地幔物质加入，填补以可见金为主的巨型矿床中黄铁矿地球化学研究空白。.4.建立胶东型金矿床成因模式与多层次勘查模型。提出流体不混溶和硫化反应是胶东金矿床最可能成矿机制；指出胶东地区金矿床既不同于经典造山型金矿，也区别于与侵入岩有关金矿的产出环境，构建“胶东型”金矿床成因模式，提出系列参数作为预测勘探新指标；在巨型金矿成矿模式和勘查模型研究领域具创新性。.发表第一标注国际SCI论文27篇（其中10篇入选ESI Top 1%高被引论文），培养研究生和博士后39人。通过与生产项目相结合，指导深部找矿取得突破。