新疆阿尔泰乌吐布拉克铁矿床矽卡岩矿物特征及其地质意义  

Skarn mineral characteristics of the Wutubulake iron deposit in Altay,Xinjiang,and their geological significance

作　　者：张志欣[1] 杨富全[1] 罗五仓 刘锋[1] 柴凤梅[3] 吕书君[4] 欧阳刘进 姜丽萍 

机构地区：[1]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点开放实验室,北京100037 [2]陕西省地质矿产勘查开发局第六地质队,陕西西安710611 [3]新疆大学地质与勘查工程学院,新疆乌鲁木齐830046 [4]中国地质大学地球科学与资源学院,北京100083

出　　处：《岩石矿物学杂志》2011年第2期267-280,共14页Acta Petrologica et Mineralogica

基　　金：“十一五”国家科技支撑计划重点项目(2006BAB07B02-01);国家自然科学基金资助项目(40672065);国土资源大调查项目(1212010786006,1212010786004)

摘　　要：乌吐布拉克中型铁矿床赋存于上志留统—下泥盆统康布铁堡组变质火山-沉积岩系中,矿体呈似层状、透镜状,矿体及其周围发育大量矽卡岩矿物。电子探针分析表明石榴石端员组分以钙铁榴石-钙铝榴石系列为主,辉石端员组分以透辉石为主,角闪石端员组分主要为铁镁钙闪石,这些特点表明矿区矽卡岩为交代矽卡岩中的钙矽卡岩。磁铁矿的主要组分、稀土及微量元素表明其形成与矽卡岩密切相关。结合矿床地质特征,认为矽卡岩是由岩浆热液流体交代康布铁堡组基性火山岩(熔岩和火山碎屑岩)及灰岩而形成的,磁铁矿的形成与矽卡岩的退化变质作用有关。The medium-sized Wutubulake iron deposit in the eastern extension of the Altay ore belt within Xinjiang is hosted in the metamorphosed volcaniclastic-sedimentary sequence of the Upper Silurian-Lower Devonian Kangbutiebao Formation.The ore bodies in the ore deposit occur as stratoids or lenses,surrounded by skars minerals.Skarn minerals include garnet,chinopyoxene,scapolite,albite,actinolite,epidote,chlorite,apatite etc.whereas ore minerals are mainly magnetite,with minor pyrite,chalcopyrite,pyrrhotite,molybdentite etc.Field evidence and petrographic observation indicate four stages of metallogenesis,i.e.,prograde stage,retrograde stage,sulfide stage and supergene stage.Electron microprobe analyses show that the end member of garnet is mainly andradite,with the calculated end number dominated by andradite（And：72.89%～84.09%,78.44% on average）,followed by almandite（Alm：8.23%～12.86%）and grossularite（Gro：3.47%～14.97%）,both of which are less than 20%.The composition of pyroxene is mainly diopside,with a small amount of augite.The end member of diopside is dominated by wollastonite（Wo：43.48%～45.84%）,followed by en-statite（En：27.02%～34.14%）and ferrosilite（Fs：18.72%～25.56%）.The amphiboles show insignificant compositional variation,mostly being ferrotschermakite.The composition of these skarn minerals suggest that skarn in the Wutubulake iron deposit is calcic skarn,belonging to metasomatic skarn.The epidote is rich in Al and Ca but poor in Fe and Ti,indicating that Fe and Ti were separated out at the same time of the formation of epidote.Electron microprobe analyses show that the composition of magnetite is mainly FeOT（91.17%～93.63%）,and most magnetite has similar chondrite-normalized rare earth element distribution patterns and is enriched in light rare earth elements,with an obvious Eu positive anomaly,which is similar to the rare earth element distribution patterns of skarns in this area.The Ni/Co values of magnetite range from 0.15 to 4.29,but most of them are lowe

关 键 词：铁矿床 矽卡岩 电子探针分析 磁铁矿 乌吐布拉克 阿尔泰 

分 类 号：P588.312[天文地球—岩石学] P618.31[天文地球—地质学]