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1、第31卷第1期地質(zhì)通報(bào)Vo1.31.No.12012年1月GEoLoGICALBULLETINOFCHINAJan.,2012韌性剪切帶的剪切作用類型和韌性減薄量李建波,王濤,郭磊。,童英,歐陽志俠,曾濤,史興俊,張建軍LIJian—bo,WANGTao。,GUOLei,TONGYing2,OUYANGZHi—xia,ZENGTao,SHIXing-jUD。,ZHANGJian-jun1.東華理工大學(xué)地球科學(xué)學(xué)院,江西撫9·I,l344000;2.中國地質(zhì)科學(xué)院地質(zhì)研究所,北京100037;3.廣東省有色金屬地質(zhì)勘查局地質(zhì)勘查研究院,廣東廣州510
2、0801.EastChinaInstituteofTechnology,Fuzhou344000,Jiangxi,China,"2.InstituteofGeology,ChineseAcademyofGeologicalSciences,BeijinglO003ZChina,"3.GeologicalSurveyInstitute,GuangdongNo咖rrousmetalsGeologicalSurveyBureau,Guangzhou510084Guangdong,China摘要:韌性剪切帶組構(gòu)的演化和剪切作用類型受到許多研究者的關(guān)注。運(yùn)用
3、極莫爾圓法、有限應(yīng)變法、剛性顆粒法、石英光軸組構(gòu)結(jié)合有限應(yīng)變測量法、拖尾形態(tài)法、剪切帶內(nèi)變形脈體(巖墻)法、碎斑法等方法可以估算剪切帶變形過程中的運(yùn)動(dòng)學(xué)渦度,進(jìn)而判別剪切帶中單剪切組分與純剪切組分的相對含量。自然界的剪切帶一般介于單剪與純剪之間,運(yùn)動(dòng)學(xué)渦度介于(卜1之間,表明韌性剪切帶在變形過程中發(fā)生了垂直于剪切帶邊界(z軸)方向的韌性減薄。剪切帶變形過程中的韌性減薄量可依據(jù)有限應(yīng)變測量與運(yùn)動(dòng)學(xué)渦度估算求得,也可依據(jù)剪切帶內(nèi)的石香腸(布丁)構(gòu)造求解,還可依據(jù)構(gòu)建極莫爾圓求解。以華北克拉通北緣的樓子店變質(zhì)核雜巖及其韌性剪切帶,以及希臘西奈山的Chel
4、mos剪切帶為例,介紹估算韌性剪切帶韌性減薄的方法,這種韌性減薄是對大規(guī)模巖石圈減薄的有益補(bǔ)充和完善。研究結(jié)果表明,定量估算與變質(zhì)核雜巖相關(guān)的韌性剪切帶的剪切作用類型是分析變質(zhì)核雜巖形成機(jī)制的有效途徑和方法。關(guān)鍵詞:韌性剪切帶;有限應(yīng)變:運(yùn)動(dòng)學(xué)渦度:韌性減薄量中圖分類號:P542+.3;P551文獻(xiàn)標(biāo)志碼:A文章編號:1671-2552(2012)O1—0026—12LiJB,WangT,GuoL,TongY,OuyangZX,ZengT,ShiXJ,ZhangJJ.Thesheartypesandtheductilethinningofthedu
5、ctileshearzone.GeologicalBulletinofChina,2012,31(1):26-37Abstract:Manyresearchershavefocusedtheirattentionontheevolutionofthefabricandtheshear押peoftheshearzone.Thekine—maticvorticitycanbeestimatedbyusingthepolarMohrmethod,thefinitestrain,therigidgrainnet,thefinitestrainandtheq
6、ua~zC一~bfic,andthecomponentsofsimpleshearandpureshearduringtheevolutionoftheductileshearzonecanalsobecalculated.Manyfactshaveconfirmedthatthenaturalshearzonesarealwaysgeneralshearzoneswhichcombinesdiferentcomponentsofsimpleshearandpureshearandwhosevaluesofkinematicvorticityran
7、gefrom0to1,suggestingthattheductilethinningperpendiculartothebandoftheshearzoneoccu~ed.Therateoftheductilethinningduringtheevolutionofcheductileshearzonecanbeestimatedbythemethodsofthefinitestraintandkinematicvorticity,thebuddingoftheshearzoneandthepolarMohr.UsingtheLouzidiand
8、uctileshearzoneandGreeceHdlenidesChelmosshearzone,thispaperin