摘要
那更康切尔沟银矿床(以下简称那更银矿)是东昆仑造山带乃至青海省内唯一的独立银矿,该矿床的勘查和研究具有非常重要的工业价值和科学意义。本次研究在较为详细的野外观察基础上,对那更康切尔沟独立银矿进行了黄铁矿LA-ICP-MS原位微量元素、硫同位素以及鄂拉山组流纹岩的铅同位素研究。PyⅠ世代黄铁矿自形程度较好,微量元素组成以富Co,Ni,Cu,贫As,Sb,Ag为特征,PyⅡ世代黄铁矿自形程度差,与毒砂共生,为低温热液的产物,As和Ag含量显著增加说明其处于主要成矿阶段,该世代黄铁矿Co/Ni平均值为1.20,暗示其类型为热液脉型。硫同位素分析显示,矿区内硫化物总体δ^(34)S值变化范围为-6.1‰~3.9‰,平均-1.79‰,表明还原硫主要来自岩浆作用;鄂拉山组流纹岩全岩铅同位素^(206)Pb/^(204)Pb,^(207)Pb/^(204)Pb和^(208)Pb/^(204)Pb平均值分别为18.30,15.63和38.52,与矿石铅三者平均值(18.34,15.65和38.60)非常相似,表明那更银矿铅源可能来自鄂拉山组火山岩。结合那更银矿床整体表现出构造控矿、脉状矿化、中低温流体的成矿特点,说明矿床成因为(中)低温热液脉型。
Nageng Kangergou silver deposit(hereinafter referred to as Nageng silver deposit)is the only independent silver deposit in east Kunlun orogenic belt and even in Qinghai Province.The exploration and research of this deposit has very important industrial value and scientific significance.On the basis of detailed field observation,the LA-ICP-MS in-situ trace elements and sulfur isotopes of pyrite and lead isotopes of Erashan Formation rhyolite in the Nageng Kangergou independent silver deposit have been studied.The results show that pyrite of PyⅠgeneration is characterized by euhedral crystal,and the trace element composition is characterized by rich Co,Ni and Cu,and poor As,Sb and Ag.Pyrite of PyⅡgeneration is characterized by irregular crystal shape,and co-exists with arsenopyrite,which is the product of low temperature hydrothermal solution.The significant increase of As and Ag contents indicates that pyrite is in the main mineralization stage.The average Co/Ni value of pyrite in this generation is 1.20,suggesting that pyrite belongs to hydrothermal vein type.Sulfur isotope analysis shows that the overallδ^(34)S values of sulfide in the mining area range from-6.1‰to 3.9‰,with an average of-1.79‰,indicating that the reduced sulfur is mainly from magmatism.The average values of ^(206)Pb/^(204)Pb,^(207)Pb/^(204)Pb and ^(208)Pb/^(204)Pb of the rhyolite in the Erashan Formation are 18.30,15.63 and 38.52,respectively,which are very similar to the average values of ore lead,which are 18.34,15.65 and 38.60 respectively,indicating that the lead source of the silver ore may come from the Erashan volcanic rocks.Based on the structural ore-controlling characteristics,vein mineralization and middle-low temperature fluid mineralization in the deposit,it is proposed that the genesis of the Nageng silver deposit belongs to the middle-low temperature hydrothermal vein type.
作者
陈静
Chen Jing(School of Geographic Sciences,Qinghai Normal University,Xining,Qinghai 810000,China)
出处
《矿物岩石》
CAS
CSCD
北大核心
2022年第1期23-32,共10页
Mineralogy and Petrology
基金
国家自然科学基金(编号:41862011,东昆仑东段地区那更康切尔沟独立银矿成因机制研究)
中国科学院“西部之光”人才培养引进计划。
