投稿时间：2014-12-03
修订日期：2015-11-25
网络发布日期：2016-02-24
中文摘要:桦树沟铜矿床位于北祁连加里东造山带西段。铜矿体赋存于镜铁山BIF 型铁矿床桦 树沟矿区FeⅤ矿体下盘,矿体受断裂构造控制,矿化岩石主要为铁碧玉岩、石英绢云母千枚 岩和碳质千枚岩,围岩蚀变可见硅化、碳酸盐化、绢云母化和绿泥石化。文章对块状铜 矿石(富铜矿体)和脉状铜矿石(千枚岩型铜矿体)进行了野外地质特征、矿物学和硫同位 素对比研究。富铜矿体与地层产状基本一致,块状矿石矿物组合为黄铜矿+少量黄铁矿+石英 +碳酸盐矿物+重晶石,黄铜矿低S、Cu,高Fe。脉状矿石主要表现为石英-碳酸盐-硫化物脉 沿千枚理或裂隙产出,矿石矿物组合为黄铜矿+黄铁矿+黝铜矿+镜铁矿+石英+碳酸盐矿物+绢 云母+绿泥石,黄铜矿低S高Fe。块状铜矿石中黄铜矿的δ34S变化范围为156‰～17 4‰,暗示硫主要来自同期海水。脉状矿石中硫化物的δ34S值低于块状矿石中黄铜 矿的δ34S值, 黄铜矿、黄铁矿的δ34S值变化范围分别为132‰～162‰和93‰～134‰,暗 示硫可能主 要来自受还原的硫化物和硫酸盐矿物。以上研究表明块状铜矿石和脉状铜矿石可能 为不同热事件的产物,结合前人研究成果,笔者认为桦树沟铜矿床为海底喷流沉积叠加后期 热液改造成因。绿泥石温度计指示后期热液成矿温度为222℃左右。
Abstract:The Huashugou copper deposit is located in the western part of the Northern Qili an Caledonian orogenic belt. Copper orebodies exist at the footwall of the FeⅤ i ron orebody in Huashugou mine of the Jingtieshan BIF-type iron deposit, and are controlled by faults. The Cu mineralization mainly occurs in iron jasperite, qua rtz-sericite phyllite and carbonaceous phyllite. Wall-rock alteration includes s ilicification, carbonatization, sericitization and chloritization. This paper pr esents a detailed comparative description of the field geology, mineral chemistr y and sulfur isotope compositions of massive copper ores (mainly hosted in high- grade copper orebodies) and vein-type copper ores (mainly hosted in phyllite-typ e copper orebodies). The attitude of the high-grade copper orebodies is concorda nt with the strata. The copper ores are composed of chalcopyrite with low conten t of Cu, S and high content of Fe, as well as minor pyrite, quartz, carbonate mi nerals and barite. Nevertheless, the vein-type copper ores occur as quartz-carbo nate-sulfide vein, and are distributed along phyllitic foliation or in the fissu re. The copper ores are composed of chalcopyrite with low content of S and high content of Fe, pyrite, tetrahedrite, specularite, quartz, carbonate minerals, se ricite and chlorite. The δ34S values of chalcopyrite from massive copper ores r ange from 156‰ to 174‰, which suggests a contemporaneous marine origin. Th e δ34S values of sulfides from vein-type ores are significantly lower than the v alues of massive ores. The δ34S values of chalcopyrite vary from 132‰ to 162‰, and the δ34S values of pyrite vary from 93‰ to 134‰, wh ich suggests tha t the sulfur was derived from early sulfide and sulfate dominated by hy drothermal reduction. All of the above data indicate that massive ores and vein- type ores are products of different thermal events. Combined with previous studi es, the authors hold that the Huashugou copper deposit belongs to submarine exha lation sedimentation-late hydrothermal fluids reform type. The chlorite geotherm ometer indicates that ore-forming temperature of the late hydrothermal stage is 222℃.
文章编号：
中图分类号：P618.41
文献标志码：
基金项目:本文由国土资源部公益性行业专项(编号: 200911007-16)和中国地质调查局地质调查项目(编号: 1212011120988)联合资助
引用文本：
杨秀清,张作衡,段士刚,赵辛敏,田宏海,杨作华.2016.北祁连桦树沟铜矿床矿物学和硫同位素特征及其成矿意义[J].矿床地质,35(1):185~195YANG XiuQing,ZHANG ZuoHeng,DUAN ShiGang,ZHAO XinMin,TIAN HongHai,YANG ZuoHua.2016.Mineralogical and sulfur isotope characteristics of Huashugou copper deposit i n Northern Qilian: Implications for metallogenesis[J].Mineral Deposits35(1):185~195
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