矿床地质2023，Vol.42Issue(6)：1121-1138,18.DOI:10.16111/j.0258-7106.2023.06.003
新疆东天山照壁山金铅锌多金属矿床地质特征及矿床成因
Geological characteristics and ore genesis of Zhaobishan Au-Pb-Zn polymetallic deposit in eastern Tianshan,Xinjiang
摘要
Abstract
The Zhaobishan Au-Pb-Zn polymetallic deposit is a new discovery in the middle segment of the Bogda is-land arc in Eastern Tianshan.The deposit is hosted by the volcanic-pyroclastic rocks of the third lithologic mem-ber of the Liushugou Formation,with the major type as veinlet and disseminated mineralization,silicification and alum alteration.The ore-forming process can be divided into three stages:①quartz-pyrite-arsenopyrite stage(Ⅰ);②quartz-gold-pyrite-sphalerite-galena stage(Ⅱ);③quartz-pyrite-chalcopyrite stage(Ⅲ).The host rock is bimod-al volcanic rock.The basalts have high values of Mg(Mg#=36.25%～58.77%),Na2O/K2O(1.95～27.35),A/CNK(1.25～1.69),belonging to the peraluminous tholite series.The high La/Nb(2.49～3.83),Ba/Nb(41.00～315.38),Ba/La(14.50～92.45)ratios indicate that the basalts have experienced a certain degree of crustal contamination.These rocks are enriched in Rb,Ba,K and depleted in Th,Nb,Ta,which are comparable with the geochemical features of intraplate basalts.The rhyolites of bimodal volcanic rocks exhibit high ALK(w(Na2O+K2O)=9.50～12.45),belonging to the potassium basalt series.They are slightly enriched in rare LERR,Rb,U,K and depleted in Nb,Ta,Sr,Ti,which indicate that the rhyolites have been derived from partial melting of crustal materials.The primary fluid inclusions trapped in quartz are mainly composed of gas and liquid.Homogenization temperatures is 194.2～253.5℃(Ⅱ),and 156.7～201.6℃(Ⅲ).Salinity is 7.9%～13.2%(Ⅱ),7.3%～12.4%(Ⅲ),respectively.The δDv-SMOW values of fluid inclusion hosted by quartz vary from-115.7‰ to-95.4‰,and δOv-SMOW values of ore-forming fluid using homogenization temperature method vary from-0.51‰ to 7.19‰,indicating that the ore-forming fluid is a mixture of magmatic water and meteoric water.Combined with systematic geological and geo-chemical comparison,it is concluded that the Zhaobihsan Au-Pb-Zn polymetallic deposit may belong to interme-diate-sulfidation epithermal deposit.关键词
地质特征/矿床成因/浅成低温热液/博格达岛弧带/东天山Key words
geologic feature/deposit genesis/epithermal/Bogda island arc belt/Eastern Tianshan分类
天文与地球科学引用本文复制引用
张雪琴,徐登峰,赵云,薛春纪,刘一浩,李旭广,陈波,游延祥..新疆东天山照壁山金铅锌多金属矿床地质特征及矿床成因[J].矿床地质,2023,42(6):1121-1138,18.基金项目
本文得到新疆维吾尔自治区人力资源和社会保障厅"天池英才"项目、地质过程与矿产资源国家重点实验室开放课题编号(编号:GPMR202307)、长安大学中央高校基本科研业务费专项资金(编号:300102263505)、企事业单位委托科技项目(编号:3-4-2021-266)联合资助 （编号:GPMR202307）
