新疆阿希与塔吾尔别克金矿床的成因联系:来自流体包裹体、S-Pb同位素和黄铁矿热电性的证据  

Genetic link between the Axi and the Tawuerbieke gold deposits,Xinjiang Province:constraints from fluid inclusions,S-Pb isotopes and thermoelectric characteristics of pyrite

作　　者：彭义伟 顾雪祥[2] 章永梅[2] 王新利[3] 郑少华[2] 王冠南[4] PENG Yiwei;GU Xuexiang;ZHANG Yongmei;WANG Xinli;ZHENG Shaohua;WANG Guannan(College of Earth Science and MLR Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation,Chengdu University of Technology,Chengdu,610059;School of Earth Sciences and Resources,China University of Geosciences,Beijing,100083;Xinda Gold&Silver Development Centre,China Nonferrous Metals Industry Association,Beijing,100038;Aluminum Corporation of China,Beijing,100082)

机构地区：[1]成都理工大学地球科学学院,国土资源部构造成矿成藏重点实验室,四川成都610059 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]鑫达金银开发中心,北京100038 [4]中国铝业集团,北京100082

出　　处：《地质学报》2020年第10期2919-2945,共27页Acta Geologica Sinica

基　　金：国家自然科学基金项目(41702081,41572062);国家重点研发计划项目(2018YFC0604003);四川省教育厅自然科学项目(18ZB0078);南京大学内生金属矿床成矿机制研究国家重点实验室开放基金项目(2018-LAMD-K07)联合资助的成果。

摘　　要：新疆西天山吐拉苏盆地中的阿希和塔吾尔别克金矿床空间上毗邻,但矿化特征差异明显。矿相学和扫描电镜-能谱成分分析表明,阿希金矿床矿石中金属矿物主要为黄铁矿、毒砂和白铁矿,塔吾尔别克金矿床矿石中金属矿物除黄铁矿外,还普遍发育黄铜矿、斑铜矿、黝铜矿、砷黝铜矿、闪锌矿和砷锑镍矿。两个矿床的流体包裹体均为盐水包裹体,具有低温、低盐度的特征。阿希金矿床浅地表黄铁矿的电子导型主要为P型,形成温度为160~240℃(平均195℃);塔吾尔别克金矿床浅地表黄铁矿以N+P混合型为主,N型和P型黄铁矿的形成温度分别为300~380℃(平均352℃)和80~240℃(平均137℃)。矿石中矿物组合和组构、流体包裹体和黄铁矿热电性特征显示,塔吾尔别克金矿床的成矿温度明显大于阿希金矿床。阿希和塔吾尔别克金矿床矿石中黄铁矿单矿物δ34S值范围分别为-4.0‰~5.3‰(平均0.7‰)和0.6‰~4.7‰(平均2.5‰),载金黄铁矿原位δ34S值范围分别为-2.6~5.6‰(平均2.4‰)和1.9‰~3.8‰(平均2.9‰),表明两个矿床具有一致的单一硫源,即岩浆硫。两个矿床矿石中黄铁矿的Pb同位素组成相似,并与赋矿大哈拉军山组火山岩和花岗斑岩大致相同,表明成矿物质来源于赋矿岩浆岩。流体包裹体、特征性矿物和矿石组构特征表明,流体沸腾作用导致了阿希金矿床金的沉淀。矿体形态产状、矿物组合、矿石组构、围岩蚀变、成矿物质来源等特征表明,阿希属于典型的低硫型浅成低温热液金矿床,塔吾尔别克可能属于斑岩与浅成低温热液之间过渡型的次浅成低温热液矿化。综合黄铁矿电子导型、矿体剥蚀率、矿物组合、矿石组构和岩体/地层出露情况等特征,推测塔吾尔别克金矿的剥蚀程度明显强于阿希金矿床,其深部可能存在隐伏的斑岩型Cu-Au矿化。The Axi andthe Tawuerbieke gold deposits,located in the Tulasu basin,Western Tianshan,Xinjiang,are adjacent to each other but show different styles of mineralization,representing the low-sulfidation epithermal,and transition between porphyry-and epithermal-type mineralization,respectively.The petrography and SEM-spectrum analysis show that the metal minerals in ores from the Axi are mainly pyrite,arsenopyrite and marcacite,whereas chalcopyrite,bornite,tetrahedrite,tennantite and aarite were commonly developed at the Tawuerbieke in addition to pyrite.The fluid inclusions in both the deposits are aqueous inclusions with low temperature and salinity.The thermoelectric conduction type of pyrite from the Axi is characterized by P type,and the calculated temperatures vary from 160℃to 240℃(average 195℃).In contrast,the thermoelectric conduction type of pyrite from the Tawuerbieke is dominated by N-P mixed type,and the corresponding temperatures of N and P type pyrite are between 300℃and 380℃(average 362℃),and between 80 and 240℃(average 137.0℃),respectively.Based on the mineral assemblages,ore textures,fluid inclusions and thermoelectric characteristics of pyrite,it is inferred that the ore-forming temperature of the Tawuerbieke is significantly higher than that of the Axi.Theδ34S values of pyrite separates in ores from the Axi and the Tawuerbieke gold deposits range from-4.0‰to 5.3‰(average 0.7‰)and 0.6‰to 4.7‰(average 2.5‰),with in-situδ34S values of Au-bearing pyrite ranging from-2.6 to 5.6‰(average 2.4‰),and 1.9‰to 3.8‰(average 2.9‰),suggesting that these two deposits display consistent sulfur source,namely the magma sulfur.The Pb isotopic compositions of pyrite from these two deposits are similar to those of the host volcanic rocks and granite porphyry,indicating that the ore-forming materials were sourced from the host magmatic rocks.Fluid inclusions,diagnostic minerals and ore textures indicate that fluid boiling was the main precipitation mechanism for the Au mineralizatio

关 键 词：斑岩-浅成低温热液金矿床 阿希 塔吾尔别克 黄铁矿热电性 西天山 新疆 

分 类 号：P618.51[天文地球—矿床学]