变质地体中内生金矿成矿模式研究—以辽东裂谷猫岭金矿为例

Maoling gold deposit, distributed in the Gaixian formation phyllitethe of Liaohe Group, is one of the most important gold deposit that located in the Proterozoic Liaodong rift. Several scholars had done researches on the deposit, however, some drawbacks and controversial issues still remains. The metallogenetic age in the deposit lacks isotopic dating constrains, characteristics of ore-forming materials and ore-forming fluid is unclear and metallogenetic model in the deposit needs proposed. Our program focus on 40Ar-39Ar geochronology of sericite, geochemistry of mineral elements and Sr-Nb-Pb-S isotope geochemistry characters in the Maoling deposit. Metallogenetic epoch, mineral resources and ore-forming fluids features were fixed under further fluid inclusions features, H-O isotope and He-Ar isotope testing technical. zircon U-Pb dating analysis from granitic Maoling intrusion in the district, mineral elements geochemistry, Sr-Nb-Pb isotope features and Hf isotope ratio analysis of zircon will be also studied to illustrate its genesis and relationship with Maoling gold deposit. Detailed contrast between classical deposit models all over the world and the Maoling gold deposit will be done to build the Maoling gold deposit model. This research not only enriches theories on endogenic gold mineralization models in metamorphic terranes but also instructs mineral resource exploration in eastern Liaoning rift.

猫岭金矿是辽东裂谷区重要大型金矿床之一，矿床产于变质地体辽河群盖县组千枚岩中。前人对该矿床做过一些研究，但仍然存在诸多不足和争议之处。矿床成矿时代缺少精确的同位素年龄制约，成矿物质来源、成矿流体性质不清，矿床成矿模式亟待建立。本项目拟对猫岭金矿开展绢云母40Ar-39Ar年代学、元素地球化学和Sr-Nb-Pb-S同位素地球化学研究，结合流体包裹体、H-O同位素和稀有气体He-Ar同位素测试技术，厘定猫岭金矿成矿时代、揭示成矿物质来源、成矿流体性质；并通过对矿区内花岗质猫岭岩体开展锆石U-Pb定年、元素地球化学、Sr-Nb-Pb和锆石原位Hf同位素地球化学研究，阐明岩石成因及与猫岭金矿成矿关系，最终确定矿床成因类型，并与国内外典型矿床成矿模式作对比，建立猫岭金矿成矿模式。该研究不但可以丰富变质地体中内生金矿成矿模式的理论研究，同时对辽东裂谷区区域找矿具有实际意义。

猫岭金矿是辽东裂谷区重要大型金矿床之一，矿床产于变质地体辽河群盖县组千枚岩中。前人对该矿床做过一些研究，但仍然存在诸多不足和争议之处。矿床成矿时代缺少精确的同位素年龄制约，成矿物质来源、成矿流体性质不清，矿床成矿模式亟待建立。本项目在详细野外地质调查基础上，开展锆石U-Pb定年、云母40Ar-39Ar年代学、元素地球化学、Sr-Nb-Pb-S同位素地球化学、流体包裹体、H-O同位素和稀有气体He-Ar同位素测工作。取得如下结论：（1）将猫岭金矿划分4 个成矿阶段：（Ⅰ）硅化石英-毒砂-绢云母成矿阶段；（Ⅱ）弯曲石英-多金属硫化物成矿阶段；（Ⅲ）平直石英-磁黄铁矿成矿阶段，（Ⅳ）石英-方解石-萤石成矿阶段；（2）确定成矿流体为中低温、中低盐度的NaCl-H2O-CH4±CO2±N2 流体体系；成矿流体主要为岩浆水后期有大气降水参与成矿，成矿流体以壳源为主，含有极少数幔源流体，流体不混溶（沸腾）是矿床成矿的主要机制；（3）查明猫岭金矿成矿物质来源，确定成矿物质主要来自于变质地层，为地层和岩浆混合源；（4）精确厘定了矿床成岩、成矿时代，确定晚侏罗世成岩、成矿事件；（5）猫岭岩体及外围卧龙泉岩体岩石均具有I 型花岗岩的特征，成岩岩浆主要来自于古老地壳部分熔融，可能少量来自于地幔；成岩背景为古太平洋板块向欧亚板块俯冲挤压的构造环境；（6）确定猫岭金矿为与岩浆热液有关的中低温热液矿床，建立猫岭金矿成矿模式。项目已完成论文16篇，其中SCI论文4篇，EI5篇，核心期刊7篇。