云南东川因民铁铜矿区绿泥石化与古地温恢复  

Characteristics of chloritization and recovery of the Paleo-geotherm in Yinmin iron-copper ore district,Dongchuan,Yunnan Province

作　　者：孙紫坚 方维萱[2] 鲁佳[2,3] 王同荣 郭玉乾[2] SUN Zi-jian;FANG Wei-xuan;LU Jia;WANG Tong-rong;GUO Yu-qian(Beijing Institute of C-eologyfor Mineral Resources,Belting 100012;China University of Geosciences,Beifing 100083;Kunming University of Science and Technology,Kunming 650093;Kunming Fengjing Mineral Co.LTD,Kunming 654102)

机构地区：[1]北京矿产地质研究院,北京100012 [2]有色金属矿产地质调查中心,北京100012 [3]昆明理工大学,昆明650093 [4]昆明风景矿业有限公司,昆明654102

出　　处：《矿产勘查》2018年第7期1379-1387,共9页Mineral Exploration

基　　金：铁氧化物铜金型矿床元素赋存状态及构造岩相学填图技术研发项目(编号:2011EG115022; 2013EG115018)资助

摘　　要：中元古界东川群因民组二段是稀矿山型铁铜矿床的主要赋存层位。为了分析稀矿山型铁铜矿床与因民组三段的铁铜矿体形成的物理化学条件,采集了云南东川因民矿区150勘探线上ZK150钻孔中的样品,研究认为从下到上具有明显的岩相学分带:火山喷发相(火山热水蚀变角砾岩)→次火山岩相(蚀变钛铁质辉绿玢岩)→火山热水浊流沉积相。在对绿泥石地质产状和镜下显微构造特征研究基础上,利用电子探针微区技术分析测试绿泥石的成分特征。将绿泥石主要类型分为密绿泥石和蠕绿泥石两类,指示绿泥石化形成于还原环境中。利用绿泥石温度计,估算绿泥石形成温度的结果显示,古地温场从下到上具有不断升温的结构,推测绿泥石化蚀变作用是在主火山喷发期(次火山岩相辉绿玢岩岩床+火山喷发相火山角砾岩)形成以后,在火山热水浊积岩相形成期,古地温场达到了最高温度,并形成了热水下渗对流循环,总体上属于中低温场范围。地球化学岩相学类型属中温-还原地球化学相,对形成铁铜和铜矿床属有利的地球化学岩相学类型。In order to analyze the physicochemical conditions of Xikuangshan type ferro-copper deposit hosted in Yinmin Formation,Dongchuan group,Mesoproterozoic Earthen and ferro-copper orebody in third member of Yinmin formation,samples were collected from ZK150 borehole of exploration line 150 in Yinmin mine area. According to the study of petrography,there is apparent zoning from bottom upwards,changing from volcanic explosion facies and subvolcanic facies to volcanic hot water turbidity sedimentary facies.Based on the study of the geological occurrence and microscopic fabric,the compositions of chlorites were analyzed by means of electron microprobe analysis. Chlorites are all classified to pycnochlorite and ripidolite,indicating chlorites formed in reducing environment. Various chlorite thermometers were utilized to calculate the formation temperature of chlorites,and the result indicated that paleo-geotemperature rise gradually from the bottom upwards. It can be speculated that chloritization was occurred after main period of volcano eruption,during which subvolcanic facies sillite sill and volcanic explosion facies volcanic breccia were formed. The Paleo-geotemperature reached the peak during formation of volcanic hot water turbidity sedimentary facies,which was generally in medium-low temperature range,and hot water infiltration-convective circulation system existed during that time. In sum,the geochemical petrographic facies are reductive facies with medium-low temperature,which are benefits to ferro-copper deposits and copper deposits.

关 键 词：稀矿山式铁铜矿床 绿泥石温度计 岩相学 物理化学条件 温度相 

分 类 号：P618.31[天文地球—矿床学] P618.41[天文地球—地质学]