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1、第29卷第4期華南地質(zhì)與礦產(chǎn)Vo1.29,No.4,271-2812013年l2月GeologyandMineralResourcesofSouthChinaDec.,2013doi:10.3969~.issn.1007—3701.2013.04.002廣西佛子沖礦區(qū)花崗閃長(zhǎng)巖成巖時(shí)代討論蔡錦輝1劉煒,韋昌山,江河,張燕揮4CAIJin-Hui,LIUWei29WEIChang-Shan,JIANGHe,ZHANGYah—Hui(1.中國(guó)地質(zhì)調(diào)查局武漢地質(zhì)調(diào)查中心,武漢430205;2.廣西佛子沖鉛鋅礦,廣西
2、梧州543003;3.中國(guó)地質(zhì)科學(xué)院地質(zhì)力學(xué)所,北京100081;4.山東省物化探勘查院,濟(jì)南250013)(1.WuhanCentreofChmaGeologicalSurvey,Wuhan430205,China;2.FuzichongPb—ZnOre,Wuzhou543100,Guangxi,China;3.InstituteofGeomechanics,ChineseAcademyofGeologicalSciences,Beijing100081,China;4.Shandongprovincial
3、Instituteofgeophysicalandgeochemicalexploration,Ji’nail250013,Chma)摘要:廣西佛子沖鉛鋅礦區(qū)巖漿巖發(fā)育,其中花崗閃長(zhǎng)巖與礦化存在密切的空間分布關(guān)系,在花崗閃長(zhǎng)巖與圍巖接觸帶形成矽卡巖化,主要鉛鋅礦體分布于矽卡巖蝕變帶中。本文通過對(duì)花崗閃長(zhǎng)巖和偉晶巖中鋯石的研究,并采用LA—ICP-MS對(duì)單顆鋯石進(jìn)行了年齡測(cè)定,分別獲得~228Ma和~248Ma兩組和諧年齡,以及一批鋯石稀土元素?cái)?shù)據(jù)。在空間上,偉晶巖脈僅僅分布于花崗閃長(zhǎng)巖附近,在偉晶巖中有花崗閃
4、長(zhǎng)巖殘留。兩組鋯石樣品中的稀土配分特征十分相似,兩者的單顆粒鋯石同位素年齡值也基本一致,這一時(shí)間與廣西欽防海槽開始閉合,華夏板塊與揚(yáng)子板塊發(fā)生碰撞的時(shí)間一致;反映出在海西.印支早期沿岑溪.博白深大斷裂有一次巖漿上侵于老地層中,形成侵入巖和鉛鋅礦床。關(guān)鍵詞:花崗閃長(zhǎng)巖;LA.ICP—MS鋯石年代學(xué);海西一印支早期;佛子沖鉛鋅礦中圖分類法:P588.12+1;P597+.3文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1007—3701(2013)04.271—11CaiJH,LiuW,WeiCS,JiangHandZhangYH.Z
5、irconU-Pbge0chrOn010gyandmineralizationsignificanceofgranodioritesfromFuzichongPb—Zndeposit,Guangxi,SouthChina.GeologyandMineralResourcesofSouthChina,2013,29(4):271—28lAbstract:GranodioriteinGuangxiFuzichonglead—zincdepositarecloselyrelatedtomineralizationi
6、nspatialdistribution,whiletheore—bodiesaremainlyoccurredinskarnzonebetweensedimentaryrocksandgranodior—ite.LA—ICP—MSzirconsU—PbdatingofgranodioriteandpegmatiteinFuzichongdepositareyieldedaverageagesof-228Maand~248Marespectively.Inspace,onlythedistributionof
7、pegrnatiteveinsnearthegran—odiorite,granodioritehaveleftinthepegmatite.TwosamplesofzirconREEcharacteristicsareverysimilar,singlezirconisotopicagesofbotharebasicallythesame,andconcordancewiththetimeofQingzhou-Fangchengtroughstartingcloseandbeginningcollision
8、ofYangtzeandCathysiaplate,whichindicatedthatFuzi—chongdepositwasformedbymagmaintrusioninoldstratumalongCenxi·-BobaideepfaultinHercynian-earlierIndosinian.Keyword:Granodiorite;LA—ICP—MSzircongeochronolo