甘新北山金窝子韧性剪切带型金矿床成因  

A discussion on origin of Jinwozi ductile shear zone type gold deposit in Beishan area of Gansu and Xinjiang

作　　者：陈柏林[1] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081

出　　处：《矿床地质》2010年第6期972-982,共11页Mineral Deposits

基　　金："十一.五"国家科技支撑计划重点项目(编号:2006BAB07B02-04)的资助

摘　　要：金窝子金矿床位于中朝-塔里木板块与哈萨克斯坦板块俯冲碰撞带南缘的甘新北山中带东段,受矿源岩系和区域性韧性剪切带的形成和演化的双重控制。下二叠统金窝子组中金元素含量高,又普遍发生浅变质作用和较强烈的构造变形作用,所以金窝子组能够提供成矿物质。区域性构造变形过程中,大规模深层次的韧性剪切变形促使金窝子组中金元素活化迁移,连同SiO2、K、Na等活性组分和岩石中H2O一起,形成含金动力变质热液;当含金热液上升并进入到NEE向低角度逆冲韧脆性断裂中,则发生交代蚀变和矿化,形成蚀变糜棱岩型和网脉型金矿化;而含金热液上升进入到NNW向高角度张性-张扭性脆性断裂中,则发生充填型矿化,形成石英大脉型金矿化。所以金窝子金矿的最主要控矿因素是矿源岩系和韧性剪切带。因此,金窝子金矿床属于韧性剪切带型金矿床,其成矿作用与控矿因素都与韧性剪切带有关。Located tectonically in the eastern section of the middle Beishan zone on the south edge of the collusion belt between Tarim-Sino-Korean plate and Kazakhstan plate,the Jinwozi gold deposit is controlled by source strata and the evolution of the regional ductile shear zone.Because lower Permian Jinwozi Group contained abundant gold and extensively experienced epi-metamorphism and structural deformation,it could provide enough materials for gold mineralization.In the process of regional structural evolution,the deep-level ductile shear deformation probably caused the gold element to be remobilized and differentiated from the source rocks,forming Au-bearing tectono-metamorphic hydrothermal solution together with the active components like SiO2,K,Na and H2O in rocks.When the Au-bearing hydrothermal solution went up and migrated along the NEE-trending low-angle thrust ductile brittle fault,metasomatic alteration and mineralization took place,forming an altered mylonite type and/or stockwork gold deposit.In contrast,when the Au-bearing hydrothermal solution migrated upward and entered the NNW-trending high angle transverse tension fault,infilling mineralization occurred and formed a quartz-vein type gold deposit.It is thus concluded that the main ore-control factors are the source strata and ductile shear zone.The Jinwozi gold deposit is a ductile shear zone type deposit,whose genesis and control factors are all related to the ductile shear zone.

关 键 词：地质学 矿床成因 韧性剪切带 金窝子金矿 甘新北山 

分 类 号：P618.510.1[天文地球—矿床学]