西藏墨竹工卡县洞中拉铅锌多金属矿矿床地质特征

成都理工大学硕士学位论文西藏墨竹工卡县洞中拉铅锌多金属矿矿床地质特征姓名：崔晓亮申请学位级别：硕士专业：矿物学、岩石学、矿床学指导教师：唐菊兴20090501摘要I西藏墨竹工卡县洞中拉铅锌多金属矿矿床地质特征作者简介：崔晓亮，男，1982年2月出生，2006年9月师从于成都理工大学唐菊兴教授，2009年6月毕业于成都理工大学矿物学、岩石学、矿床学专业，获理学硕士学位。摘要隆格尔－念青唐古拉火山岩浆弧带东段西以当雄－羊八井断裂为界，北、东以永珠－嘉黎－波密缝合带为界，南以沙莫勒－麦拉－洛巴堆－米拉山断裂为界。带内岩浆活动强烈，无论火山岩还是花岗岩类岩石都十分发育。自晚古生代以来，带内亦广泛发育浅海、半浅海和海陆交互相的碳酸盐岩-碎屑岩沉积，为夕卡岩矿床的形成提供了得天独厚的地质条件。洞中拉铅锌多金属矿床位于隆格尔－念青唐古拉火山岩浆弧东段南缘，地处隆格尔－工布江达断隆带与冈底斯－下察隅晚燕山-喜马拉雅岩浆弧的接合部位，属于念青唐古拉－上察隅Pb-Zn(Cu)-Fe成矿亚带。念青唐古拉中生代岛链隆起带主要为前奥陶纪地层，发育有多期次酸性侵入岩，断裂构造主要发育近东西向逆断层，区域上经历了多期次多种类型的变质作用。在石炭纪－早二叠世，由于班公湖－怒江特提斯洋的形成，断隆带东段沉积了一套含陆内双峰式火山岩的碎屑岩地层，包括诺错组(C1n)、来菇组(C2-P1l)。中二叠世该区首次由被动大陆边缘转变成活动大陆边缘并沉积了一套含岛弧双峰式火山岩的碳酸盐岩地层－洛巴堆组(P2l)。有利于夕卡岩形成的岩石主要为灰岩、生物灰岩、泥灰岩、富钙质泥岩、火山凝灰岩等，碳酸盐岩地层中的CaO、CO2等成分加入对夕卡岩的形成有重要影响。区内岩浆岩极为发育，主要形成于燕山晚期至喜马拉雅期。燕山期岩浆岩以中酸性岩为主，喜马拉雅期岩浆岩以酸性岩为主。与成矿有关的岩体主要为新生代石英二长花岗岩、石英二长岩、二长花岗岩（斑岩）、黑云角闪二长花岗岩等。本次研究对洞中拉铅锌多金属矿床的地质特征进行了详细地剖析；从地层、构造、岩体等控矿因素分析入手，结合区域上的研究成果，对矿床成因进行了初步探讨。研究表明，在矿区内沿地层走向范围内铅锌矿化呈分段富集的特点。在矿化集中区，矿体的形状、产状受围岩控制。显示出层控性的特征。而位于矿区中部的断裂是矿液的运移通道。矿床发育了一系列的热液蚀变系列。工业矿体即赋存于强蚀变地段。矿床具多阶段叠加的特征。根据矿床产出的构造背景，矿体定位成都理工大学硕士学位论文II的岩石环境，初步认为，本矿床为夕卡岩型的铅锌矿床。关键词：冈底斯成矿带夕卡岩型洞中拉铅锌多金属矿矿床地质特征AbstractIIIGeologicalCharacteristicofLead-ZincPolymetallicDepositinMedroGongkarCountry，TibetIntroductionoftheauthor:Cuixiaoliang,male,wasborninFebruary,1982whosetutorwasProfessortangjuxing.HegraduatedfromChengduUniversityofTechnologyinmineralogy-lithology-metallogenymajorandwasgrantedtheMasterDegreeinJune,2009.AbstractTheeastsegmentofLonggeer-NianqingtanggulamagmaticarcisdelimitedbyDangxiong-Yangbajingfaultinthewest,Yongzhu-Jiali-Bomisuturezoneinthenorthandeast，andShamole-Luobadui-Milashanfaultinthesouth.Themagmaticactivityinthisregionwasveryfierceandfrequent.Eithervolcanicorgranitoidrocksarewidelypresent.Inaddition,sinceLatePaleozoic,thisareahasbeencharacterizedbyextensivelydistributedcarbonate-clasticrockassociationssedimentatedfromshallowsea,epineriticenvironment,marine-continentexchangeenvironment.AlloftheseexceptionallygeologicconditionscontributedsignificantlytotheformationofSkarndeposits.Dongzhonglalead-zincpolymetallicdepositislocatedinthesouthmarginofeastLonggeer-Nianqingtanggulamagmaticarc,inthejunctionoftheLonggeer-Gongbo'gyamdafault-upliftbeltandGangdise-latterZayülaterYanshanian-Himalayamagmaticarc,fallingintotheNianqingla-ShangchayuPb-Zn(Cu)-Femineralizedsub-zone.NyainqentanglhaMesozoicisland-chainupliftbeltismainlythePreordovicianstrata,developedanumberofstagesofacidicintrusiverocks,thefaultconstructionsarenearlyeast-westtendencyreversefaults,theregionexperiencedanumberofstagesofvarioustypesofmetamorphism.IntheCarboniferous-EarlyPermian,asformationofthePangongLake-NujiangTethys,therewasdepositedheclasticrockterranecontainingainlandbimodalvolcanicrocksintheeasternsectionofthefault-upliftbelt,includingtheNuocuogroup(C1n),Laigugroup(C2-P1l).InthePermian,thisareafirstlychangedfromapassivecontinentalmarginintoanactivecontinentalmargin,anddepositedasuiteofthecarbonateformations-Luobaduigroup(P2lb)includingabimodalisland-arcvolcanicrocks.Conducivetotheformationofskarnrocksaremainlylimestone,bio-limestone,marl,rich-calcareousmudstone,volcanictuff,etc.CaO,CO2andothercomponentsinthecarbonateformationhadimportantimpactfortheformationofskarn.Magmaticrocksintheregiongreatlydeveloped,mainlyformatedintheHimalayasandtheLaterYanshanian.Yanshanianmagmaticrockswereintermediate-acidrocks,andtheHimalayanmagmaticrocksweremainacidrocks.ThemagmaticbodiesrelatedtomineralizationweremainlytheCenozoicquartzadamellite,quartzsecondandadamellite(porphyry),hornblende成都理工大学硕士学位论文IVbiotitemonzogranite,etc.Duringtheresearch，thegeologicalfeaturesofdongzhonglapolymetalliclead-zincdepositisstudiedindetail.Onthebasisofanalysisofore-controllingfactorssuchasstrata，structure，andintrusionbody，combinedwiththeregionalresearchachievements，theoriginofdepositisdiscussedpreliminarily.Studieshaveshownthat，alongthestratatotheextent，thecharacteristicsoflead-zincmineralizationwassub-concentrationintheminingarea.Inthecentralizationareaofthemineralization，theshapeandattitudeoftheorebodywascontroledbythewallrock.itshowsthecharacteristicsofstrata-bound.Butthefaultlocatedinthecentralpartofthemineralizationareaistheminefluidmigrationpathway.Thedepositdevelopedaseriesofhydrothermalalteration.Industrialorebodyoccurredinthestronglyalteredarea.Thedeposithadthecharacteristicsofmulti-stagestack.Basedonthestructurebackgroundofthedepositoutput，aswellastherockenvironmentoftheorebodyposition，itpreliminarilyviewedthatthedepositbelongtotheskarn-typelead-zincdeposit.Keyword：Gangdisimetallogenicbelt；Skarn-Type；DongzhonglaLead-ZincPolymetallicDeposit；GeologicalCharacteristicofDeposit第1章前言1第1章前言1.1地理位置和自然地理条件研究区行政区划隶墨竹工卡县门巴乡管辖（图1-1）。地理坐标为东经92°35′～92°42′，北纬30º12′～30º14′，面积达19.85km2。图1-1工作区交通位置图（据西藏地勘局第二地址大队，2003）研究区位于冈底斯山脉东段，地势西高东低、谷深坡陡。属高原中高山区，区内海拔一般4540～5860m，平均海拔大于5000m，最高处位于工作区北侧的哈拉航日雪山，海拔6400m；最低处位于工作区东南部的沙让与翁浪交汇处，海拔仅4500m。相对高差500～800m。区内水系相对发育，均属雅鲁藏布江水系。以哈拉航日为分水岭，东侧水系自北西流向东南，汇入尼洋河；西侧水系自北东流向西南，汇入拉萨河支流－血弄藏布。区内由于铁质污染严重，多数河流水不宜人畜饮用。水源为大气降水、冰雪融水。区属于高原温带半干旱季风气候区。旱、雨季分明，6月至9月为雨季，气候湿润，常有暴雨及雨夹