胶莱盆地东北缘龙口-土堆矿区金矿床成矿规律研究

Study on metallogenic regularity of gold deposits in Longkou-Tudui mining area on the northeastern margin of Jiaolai basin

海阳市龙口-土堆金矿床是胶莱盆地东北缘金矿床的重要典型矿床之一。金矿床位于胶莱盆地东北缘一个微凸起,以NE向断裂面为界。矿体严格受断裂构造控制,主要矿体受控于NE走向、SE倾的左行压扭性断裂构造,并在构造的引张和产状变化部位形成厚大矿体;矿床成因为岩浆期后中低温热液构造蚀变岩型金矿;成矿时间集中在119±10Ma。成矿热液中硫源可能与脉岩来自同一或类似源区,在上升成矿过程中又萃取了围岩荆山群中的硫及成矿物质。胶莱盆地东北缘金成矿带成矿流体相似,均为岩浆水混合大气水。主成矿期成矿流体为中高温、低盐度的CO2-NaCl-H2O体系。成矿期次划分为热液期和表生期两个阶段。

Longkou-Tudui gold deposit in Haiyang city is one of the important typical gold deposits in the northeast margin of Jiaolai Basin.The gold deposit is located in a microuplift in the northeast margin of Jiaolai Basin,bounded by NE trending fault surface.The orebody is strictly controlled by fault structure,the main orebody is controlled by NE strike,the left lateral compression-torsional fault structure of SE tilting,and the thick orebody is formed in the extension and occurrence of the structure;the deposit is formed because of the alteration rock type gold deposit of middle and low temperature hydrothermal structure after magmatic period;the mineralization is concentrated in 119±10 Ma.The sulfur source in the ore-forming hydrothermal solution may come from the same or similar source area as the vein rock,and the sulfur and ore-forming materials in the surrounding rock Jingshan Group are extracted in the process of ascending mineralization.The metallogenic fluids in the gold metallogenic belt in the northeast margin of Jiaolai Basin are similar,all of which are magmatic water mixed with atmospheric water.The main metallogenic fluid is CO2-NaCl-H2 O system with medium and high temperature and low salinity.The metallogenic stages are divided into hydrothermal stage and epigenetic stage.It is a post-magmatic hydrothermal structural altered rock type gold deposit.