湘西北洛塔矿田铅锌矿床与典型MVT铅锌矿床的对比研究.pdf

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1、总第199期南方金属Sum．1992014年8月S0UTHERNMETALSAugust2014文章编号：1009—9700(2014)04—0005—09湘西北洛塔矿田铅锌矿床与典型MVT铅锌矿床的对比研究彭能立，梁恩云，刘伟，刘庚寅，袁甫，熊苗，黄乐清，王业成(湖南省地质调查院，湖南长沙410016)摘要：洛塔矿田处于扬子地台东南边缘，矿田内的铅锌矿床(点)分布受断裂、褶皱构造控制，分布在三个背斜的核部．矿体主要赋存于奥陶纪南津关组生物屑灰岩及硅化灰岩中，呈似层状、脉状．围岩蚀变有硅化、方解石化、白云石化、黄铁矿化等，硅化是最直接的找矿标志．成矿硫质主

2、要源于同沉积的海水硫酸盐，铅主要源于造山带，具壳幔混合源性质．成矿流体为含烷类(CH)有机质地下热卤水，成矿温度介于95—197oC．铅同位素模式年龄指示矿石的形成明显晚于赋矿层位，矿床成因类型属层控型浅成低温热液矿床．通过对比发现，洛塔矿田铅锌矿床在矿床地质特征、同位素地球化学、成矿流体、矿床成因等方面都与典型MVT矿床具有一定相似性，又具有独特的性质．关键词：铅锌矿床；MVT；矿床成因；洛塔矿田；湘西北中图分类号：P61文献标识码：AAComparativeStudyofLuotaOreFieldLead——zincDepositsintheNorth

3、westofHunanProvincewithTypicalMVTLead—-zincDepositsPENGNeng—li，LIANGEn—yun，LIUWei，LIUGeng～yin，YUANFu，XIONGMiao，HUANGLe—qing，WANGYe—cheng(HunanInstituteofGeologicalSurvey，Changsha，410016，P．R．China)Abstract：LuotaorefieldislocatedinthesoutheasternedgeoftheYangtzePlatform，Thelead—zinc

4、depositsintheorefieldisdistributedinthreecoreoftheanticlinewhicharecontrolledbybreaksandfolds．Theore—bodiesmostlypresentaslayerandveinwhicharemostlyhostedintheNanjinguangroupbioclasticlimestoneandsilicifiedlimestoneofOrdovician．Thereareseveralwall—rockalterationsintheorefieldsucha

5、ssilicification，calcitization，dolomitization，pyritization．etc，silicificationwhicharethemostdirectprospectingmark．Sulfurmineralizationismainlyderivedfromthesyndepositionalseawatersulfate，leadmineralizationismainlyfromorogenicbelt，withtheinformationofcontaminatingthecrustandman—tlem

6、ixedsource．Theore—formingfluidsarehotbrinefromundergroundcontainingorganicalkaneslikeCH4．Thetemper—atureofmineralizationiSbetween95～197℃．PbisotopicmodelagesindicatethattheformationoforeiSsignificantlylaterthantheOre—bearingstratum．Thedeposittypeismostlikestrataboundepithermaldepos

7、it．Bycomparison，thegeolog-icalcharacteristics，isotopicgeochemistry，ore—formingfluids，genesisofthedepositinLuotaorefieldhavesomesimilari—tieswithtypicalMVTdeposit，butalsoithasitsuniqueness．Keywords：lead—zincdeposits；MVT；genesisofdeposit；Luotaorefield；NorthwestofHunanProvince的铅锌成矿集中

8、区．洛塔铅锌矿田位于湘西北铅锌0引言矿带的西北部，呈北东走向，北东