遼西醫(yī)巫閭山北段中生代構(gòu)造格架及其對(duì)金礦形成富集與分布的控制作用
本文關(guān)鍵詞:遼西醫(yī)巫閭山北段中生代構(gòu)造格架及其對(duì)金礦形成富集與分布的控制作用,由筆耕文化傳播整理發(fā)布。
遼西醫(yī)巫閭山呈北東走向,西鄰阜新盆地,東鄰下遼河坳陷。研究區(qū)屬華北地塊北緣的燕山陸內(nèi)造山帶的東北端的阜新金礦集中區(qū),是東西走向的燕山北緣圍場-赤峰-阜新金銀銅成礦帶與北東走向的綏中-錦州-阜新金鉛鋅鉬成礦列的交匯處。因此,對(duì)遼西醫(yī)巫閭山北段中生代構(gòu)造格架及其對(duì)金礦形成富集與分布的控制作用研究具有重要意義。論文對(duì)醫(yī)巫閭山北段阜新金礦集中區(qū)的構(gòu)造演化歷史,尤其是中生代以來的區(qū)域構(gòu)造特征與金礦形成富集的關(guān)系作了深入的研究,,以期為本區(qū)資源規(guī)劃、評(píng)價(jià)及礦產(chǎn)勘探工作提供區(qū)域成礦構(gòu)造學(xué)方面的依據(jù)。遼寧阜新地區(qū)醫(yī)巫閭山北段以排山樓特大型金礦的發(fā)現(xiàn)而著稱于世。論文在緊密結(jié)合地質(zhì)背景、構(gòu)造背景研究的基礎(chǔ)上,以地質(zhì)事件為主線,分析該地區(qū)域成礦構(gòu)造的成生歷史,特別是燕山運(yùn)動(dòng)以來繼承及新生的構(gòu)造體系格架與濱太平洋成礦構(gòu)造域的盆嶺構(gòu)造、閭山巖體熱隆、變質(zhì)核雜巖等3個(gè)不同級(jí)別的區(qū)域成礦構(gòu)造系統(tǒng)。重點(diǎn)以排山樓、大板、大櫻桃溝、五家子等金礦礦田構(gòu)造調(diào)查為基礎(chǔ),以區(qū)域地質(zhì)構(gòu)造、地球物理、地球化學(xué)研究為背景,輔以成礦構(gòu)造物理模型、數(shù)學(xué)模型,通過成礦構(gòu)造、控礦構(gòu)造研究,將本區(qū)金礦的成礦構(gòu)造確認(rèn)為變質(zhì)核雜巖拆離滑脫剪切帶,并且是與區(qū)域成礦構(gòu)造系統(tǒng)相聯(lián)系,在不同時(shí)期、不同級(jí)序、不同力學(xué)性質(zhì)構(gòu)造體系成分復(fù)合條件下成礦。經(jīng)過三年的野外地質(zhì)調(diào)查和室內(nèi)的綜合研究工作,取得了如下進(jìn)展:1、通過區(qū)域成礦構(gòu)造分析,重新擬定并闡述了成礦構(gòu)造演化史。結(jié)合深部地質(zhì)、物探和遙感解譯資料,劃分了遼東巫閭山地區(qū)構(gòu)造體系和構(gòu)造帶歸屬、韌性剪切帶與變質(zhì)核雜巖的時(shí)代、范圍分區(qū)及其復(fù)合關(guān)系。認(rèn)為阜新地塊是在克拉通裂陷槽基礎(chǔ)上發(fā)育起來的,經(jīng)歷了海西期陸緣褶皺始造山、印支—早燕山陸內(nèi)褶斷主造山、晚燕山—早喜馬拉雅陸內(nèi)盆山后(重)造山等過程。2、遼寧醫(yī)巫閭山地區(qū)出露的構(gòu)造體系有緯向、經(jīng)向、北西向、華夏、新華夏、旋扭構(gòu)造體系等,這些構(gòu)造體系的成生演化與該區(qū)金-多金屬礦富集成礦有著密切的關(guān)系,尤其是構(gòu)造體系的復(fù)合與聯(lián)合、深部地質(zhì)作用與構(gòu)造體系的聯(lián)系,是控制該區(qū)金礦的主要構(gòu)造因素。3、通過對(duì)小型構(gòu)造、顯微構(gòu)造、X射線巖組等礦田構(gòu)造分析,判明本區(qū)至少經(jīng)歷了2~3期(成礦前、成礦期、成礦后)脆-韌性構(gòu)造變形。從構(gòu)造巖、礦物巖石形變、相變特征的差異,論述了本區(qū)NE、EW向兩種主要控礦構(gòu)造的相關(guān)性,并根據(jù)巖石組構(gòu)對(duì)導(dǎo)礦、容礦構(gòu)造的運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)方式作了詳細(xì)劃分。4、通過區(qū)域構(gòu)造、控礦構(gòu)造分析、聲發(fā)射歷史地應(yīng)力測(cè)量、古應(yīng)力值估算等技術(shù),確中國地質(zhì)大學(xué)(北京)博士學(xué)位論文立了中生代以來成礦前、成礦期、成礦后等三期區(qū)域構(gòu)造應(yīng)力場的主應(yīng)力值和方位,首次建立了遼寧醫(yī)巫閣山地區(qū)變質(zhì)核雜巖及鄰區(qū)的構(gòu)造物理模型和有限單元數(shù)值法數(shù)學(xué)模型。5、分析了本區(qū)區(qū)域控礦構(gòu)造、變質(zhì)核雜巖成礦地質(zhì)地球化學(xué)背景,認(rèn)為金成礦物質(zhì)具有多來源性,本區(qū)及鄰區(qū)熱事件和同位素年齡落在燕山期。毛景文等(毛景文等,2000)獲得排山樓金礦形成年齡為120Ma,新近的結(jié)石U-Ph法測(cè)得排山樓與金礦化相關(guān)的花崗巖侵位年齡為124Ma(苗來成,2000),本項(xiàng)研究所測(cè)全巖K-Ar法成礦一蝕變平均年齡為11OMa,可見排山樓金礦形成年齡主要為晚燕山期,這也反證了阜新地區(qū)最強(qiáng)烈的構(gòu)造運(yùn)動(dòng)及變形一熱事件發(fā)生在燕山期。6、首次在本區(qū)劃分了與大地構(gòu)造演化、變質(zhì)核雜巖構(gòu)造系統(tǒng)相聯(lián)系的變形序列及相應(yīng)的控礦構(gòu)造型式、成礦序列和礦化類型。在沉積一巖漿一變質(zhì)建造、語皺變形、推覆/滑脫剪切帶等發(fā)育的基礎(chǔ)上出現(xiàn)了中生代的構(gòu)造復(fù)合,在N’’NE向構(gòu)造的力學(xué)性質(zhì)轉(zhuǎn)化為偏張性時(shí)期為本區(qū)主要的疊生復(fù)合成礦期。新華夏系*口一NLNB向斷裂與緯向、北西向斷裂復(fù)合,在本區(qū)組成網(wǎng)格狀構(gòu)造樣式,醫(yī)巫閻山北段同造山侵位花崗巖體強(qiáng)化了變質(zhì)核雜巖區(qū)的應(yīng)變圖像,并使北東方向的圍巖構(gòu)成透鏡狀壓力影,分別是遍及全區(qū)的和中南段最突出的區(qū)域成礦系統(tǒng)。7、明確了燕山運(yùn)動(dòng)在阜新地區(qū)是最為重要的成礦地質(zhì)事件。中生代燕山運(yùn)動(dòng)以來太平洋板塊在該區(qū)東側(cè)向NW俯沖到巖石圈之下,本區(qū)地殼層次受到向NW的擠壓產(chǎn)生基底滑脫、推覆增厚,并在擠壓與松弛伸展交替變化的過程中出現(xiàn)韌性剪切、盆嶺構(gòu)造、變質(zhì)核雜巖、重力滑脫、花崗巖熱隆,這就成為阜新地區(qū)及鄰區(qū)構(gòu)造一巖漿一成礦作用最為關(guān)鍵的地質(zhì)事件。8、通過區(qū)域成礦構(gòu)造與礦田構(gòu)造分析,作者認(rèn)為醫(yī)巫閣山北段金礦的控礦構(gòu)造,為環(huán)繞醫(yī)巫間山變質(zhì)核雜巖隆起中心的向NE突出的一套弧形推覆/滑脫型韌一脆性剪切帶,且大致十等距分布。9、最后,本項(xiàng)研究將遼寧醫(yī)巫門山北段劃分為2個(gè)一級(jí)成礦帶、10個(gè)二級(jí)成礦遠(yuǎn)景K。在進(jìn)行全面評(píng)價(jià)的基礎(chǔ)上,提出廠五家于一梨樹營于區(qū)、11。大櫻桃溝一老河土區(qū)、117人巴區(qū)、118排山樓區(qū)、川大市堡于區(qū)是5個(gè)可近期加強(qiáng)工作的目的區(qū)。同時(shí)指出117、山是重點(diǎn)_[作、擴(kuò)大探明儲(chǔ)量最為有望的地段。');ReplaceFont('EnDivSummary','TheNE-trendingYiwulushanMountainsislocatedinwesternLiaoningProvincewiththeFuxinbasinasitswesternboundaryandXialiaohedepressionasitseasternboundary.OurstudyareabelongstotheFuxinAu-concentratingzoninginnortheasternpartoftheYanshanintercontinentalorogenyinnorthernmarginoftheHuabei(NorthChina)Block,whereconvergetheEW-trendingWeichang-Chifeng-FuxinCu-concentratingzoninginnorthernYanshanorogenyandtheNE-trendingSuizhong-Jinzhou-FuxinAu-Pb-Zn-Momineralizationsequence.Thus,itisveryimportanttostudytheMesozoicstructureinthenorthsegmentoftheYiwulushanMountains,westernLiaoningProvinceanditscontrollingovertheenrichmentanddistributionofgolddeposits.InthisdissertationtheauthormainlydiscussedthetectonicevolutionoftheFuxinAu-concentratingareainthenorthsegmentoftheYiwulushanMountains.ThecharacteroftheregionalstructureanditsrelationtotheenrichmentofgolddepositssinceMesozoicweredeeplygoneintobytheauthortoprovidethebasisofregionalore-formingstructuresfortheplanningandevaluationaswellasexplorationofmineralresources.ThenorthsegmentoftheYiwulushanMountains,westernLiaoningProvinceiswellknownbecauseofthediscoveryofthesuper-largePaishanlougolddeposit.Basedonthestudyofgeologicalbackgroundandstructuralsettings,andwiththegeologicaleventasthemainthread,theauthoranalyzedthedevelopmenthistoryoftheregionalore-formingstructures,especially,thenew-formingandinheritedstructuralsystemssinceYanshanianmovement,andtherange-basinstructuresofmarginal-Pacificore-formingdomain,andthethermo-upliftingstructureoftheLushanore-bodyaswellastheYiwulushanmetamorphiccorecomplex,whicharethreedifferentscaleore-formingstructuralsystems.ThekeystudiedareasarethePaishanlou,Daban,Dayintaogou,Wujiazigolddeposits.Intermsofthestudyofregionalstructures,geophysics,andgeochemistry,andnecessarytectono-physicalandnumericalmodeling,aswellasstudiesofore-formingandore-controllingstructures,theauthorholdsthatthedetached-ductileshearingzoneofthemetamorphiccorecomplexisthemainore-controllingstructuralsystem,andtheregionalmineralizationisrelatedwiththeregionalore-formingstructuralsystemswhicharecontrolledbycompoundingofregionalstructuralsystemswithdifferenttimeandgrade.Afterthree-yearhardworkbothinfieldandlaboratory,themainadvancementachievedisasfollowing:1.Accordingtothestudyofregionalore-formingstructures,theauthorrenewedlyexpatiatedontheevolutionhistoryofore-formingstructures.Thedivisionofregionalstructuralsystemsinthestudyarea,thetiminganddistributionrangeoftheductileshearingzoneandthemetamorphiccorecomplex,andtheircompoundingweremadebytheauthorinthelightofresultsofthesyntheticstudyongeologyindeep,geophysicalprospecting,andinterpretationofremotesensingimage.TheauthoralsosuggestedthattheFuxinblockdevelopedonthebaseofthegeosynclineintheHuabeicraton,andhadexperiencedthreeperiodprocessoforogeny,includingHercynianfoldingorogenyincontinentalmargin,mainlyIndo-SiniantoEarlyYanshanianintracontinentalfold-faultingorogeny,andLateYanshaniantoEarlyHimalayaianintracontinentalrange-basinpostorogeny.2.Structuralsystemsexposedinthestudiedareaincludelatitudinal,NS-trending,NW-trending,Cathaysian,Neocathaysian,androtated-andsheared-relatedstructuralsystems,theenrichmentandformationofgoldandmulti-metaldepositweretightlyrelatedwiththeformationanddevelopmentofabove-mentionedstructuralsystems.Especially,thecompoundandjointofthosestructuralsystems,andtheirrelationtothegeologicalprocessindeep,weremainlyore-controllingfactorsofgolddepositsinthisarea.3.Analysesofsmall-scalestructures,microstructures,X-raypetrofabricshowedthatthes');
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本文關(guān)鍵詞:遼西醫(yī)巫閭山北段中生代構(gòu)造格架及其對(duì)金礦形成富集與分布的控制作用,由筆耕文化傳播整理發(fā)布。
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