胶东谢家沟金矿热液蚀变作用过程的元素迁移规律  

Element migration regularity during hydrothermal alteration in the Xiejiagou gold deposit,Eastern Shandong Province

作　　者：杜泽忠[1] 程志中[1] 姚晓峰[1] 于晓飞[1] 陈辉[1] 李少华 鲍兴隆 无 DU Zezhong;CHENG Zhizhong;YAO Xiaofeng;YU Xiaofei;CHEN Hui;LI Shaohua;BAO Xinglong(Development and Research Center,China Geological Survey/Technical Guidance Center for Mineral Resources Exploration,Ministry of Natural Resources,Beijing 100037,China;Jintingling Mining Industry Co.,Ltd.,Zhaoyuan 265400,Shandong,China)

机构地区：[1]中国地质调查局发展研究中心/自然资源部矿产勘查技术指导中心,北京100037 [2]招金集团金亭岭矿业公司,山东招远265400

出　　处：《地质通报》2020年第8期1137-1152,共16页Geological Bulletin of China

基　　金：国家重点研发计划项目课题《深部矿产资源三维找矿预测评价示范》(编号:2017YFC0601506);中国地质调查局项目《整装勘查区找矿预测与技术方法示范》(编号:DD20160050);《整装勘查区矿产地质调查与找矿预测》(编号:DD20190159)。

摘　　要：谢家沟金矿床位于胶西北焦家断裂带和招平断裂带之间。通过详细的野外地质观测与室内研究,查明了谢家沟金矿床的蚀变类型及空间分带,系统采集不同蚀变类型的岩石样品,进行岩石元素地球化学分析,运用Isocon方法分析探讨了热液蚀变过程中的元素迁移规律及其对成矿流体性质、矿质沉淀的制约。蚀变从中心到两侧分别为含陡立石英脉的黄铁绢英岩化、黄铁绢英岩化、钾长石化;从早到晚依次为钾长石化、黄铁绢英岩化、含陡立石英脉的黄铁绢英岩化。钾长石化蚀变表现为钾长石和黑云母分别交代玲珑黑云母花岗岩中的斜长石和角闪石,K明显的迁入,Si轻微迁入,Ca、Mg为迁出,Fe轻微迁出。黄铁绢英岩化蚀变叠加于钾长石化蚀变之上,主要表现为斜长石、钾长石、黑云母等矿物在含H+、HS-溶液中失稳,被绢云母、石英替代,Fe、Mg、Ca为迁入,K、Na、Si表现为元素迁出。从钾长石化阶段到黄铁绢英岩化阶段,流体从碱性转变为酸性;Au迁移形式也逐渐由氯的络合物转化为硫氢络合物。随着成矿流体的不断演化,成矿流体与围岩不断反应,含矿热液化学性质不断变化促进了金的沉淀。The Xiejiagou gold deposit is located between the Jiaojia fault zone and the Zhaoyuan-Pingdu fault zone in northwest Jiaodong.Based on detailed field geological observations and laboratory study,the authors identified the alteration types and spatial zoning of the Xiejiagou gold deposit.In this paper,the authors systematically collected rock samples of different alteration types,and carried out geochemical analysis of rock elements.The Isocon method was used to analyze the element migration law during hydrothermal alternation and its constraint on the properties of ore-forming fluids and mineral precipitation.The alterations of the gold deposit are beresitization of steep quartz veins as well as beresitization and K-feldspathization from the center to both sides;they are K-feldspathization,beresitization,and ferritic lithology with steeply dipping quartz veins from early to late period.The K-feldspathization shows that K-feldspars and biotite replaced the plagioclases and hornblende in the Linglong biotite granite,respectively,the potassium obviously migrated in,silicon slightly migrated in,calcium and magnesium migrated out,and iron migrated slightly out.The beresitization is superimposed on the K-feldspathization,which mainly demonstrates that plagioclase,K-feldspar and biotite were destabilized in the solution containing H+and HS-,and were replaced by sericite and quartz.Iron,magnesium,and calcium moved in,potassium,sodium,and silicon moved out.From the K-feldspar stage to the beresitization stage,the fluid changed from alkaline to acidic,and the migration form of Au also gradually changed from a chloride complex to a sulfur-hydrogen complex.With the continuous evolution of the ore-forming fluid,the ore-forming fluid and the surrounding rock continuously reacted,and the chemical properties of the ore-bearing hydrothermal fluid continued to change to promote the precipitation of gold.

关 键 词：谢家沟 金矿 围岩蚀变 Isocon方法 元素迁移规律 

分 类 号：P618.51[天文地球—矿床学]