吉南石棚沟—夹皮沟—金城洞金矿带矿床地质特征及成因研究

Geological characteristics and genesis of the Shipenggou-Jiapigou-Jinchengdong gold belt in South Jilin Province

石棚沟—夹皮沟—金城洞金矿带是吉林省南部重要的金成矿带,其内分布有大中小型金矿床20余处。通过对带内典型金矿床的地质特征进行对比、分析,结果表明:石棚沟金矿床、夹皮沟金矿床、海沟金矿床和金城洞金矿床地质特征基本相似,是同一成矿作用下的产物;金矿床受太古宇变质岩、燕山早期中酸性侵入岩及断裂构造“三位一体”控制,太古宇变质岩的部分熔融为中生代成岩、成矿提供了物源;燕山早期黄泥河岩体、海沟岩体成岩年龄(约160~185Ma)与成矿年龄(160~178Ma)相吻合,为成矿母岩体,岩体具有埃达克质岩化学成分特征,为中生代燕山早期古太平洋板块俯冲、加厚下地壳部分熔融形成。综合分析认为,石棚沟—夹皮沟—金城洞金矿带内的金矿床是与古太平洋板块俯冲背景有关的造山型金矿床。

The Shipenggou-Jiapigou-Jinchengdong gold belt is an important gold mineralization belt containing more than 20 gold deposits of various scale in the South Jilin Province.Based on the comparison and analysis of the geological characteristics of the typical gold deposits in the belt,it is demonstrated that the Shipenggou,Jiapigou,Haigou and Jinchengdong gold deposits are basically similar in geological characteristics and are the products of the same mineralization.The Archaean Eonothem metamorphic rocks,the Early Yanshan intermediate-acid intrusive rocks and the fault structure in "Trinity" control the gold deposits.The partial melting of the Archaean Eonothem metamorphic rocks provides a provenance for Mesozoic diagenesis and mineralization;The diagenesis of the Early Yanshan Huangnihe rock mass and the Haigou rock mass (about 160-185 Ma) coincides with the mineralization age (160-178 Ma),which turn out to be the mineralization parent rock mass with the chemical composition characteristics of the adakite-like rocks.These rock masses were formed by partially melting of the thickened lower crust and the subduction of the ancient Paleo-Pacific plate in the Early Yanshan.The comprehensive analysis holds that the deposits in the Shipenggou-Jiapigou-Jinchengdong gold belt are orogenic gold deposits related to the subduction background of the Paleo-Pacific plate.