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作者刘昕悦（2019）在《华北克拉通东部太古代构造样式研究及数值模拟》一文中研究指出：太古宙地壳的构造样式一直是地学界研究的热点问题之一,存在着垂向构造和水平构造两大不同的构造演化认识。位于华北克拉通东缘的辽东鞍山地区广泛出露太古宙TTG岩系、绿片岩相变质的基性-中酸性火山岩/火山沉积岩、硅铁质沉积建造构成了典型的太古宙花岗-绿岩带。此外,花岗-绿岩带内丰富的构造变形记录,为探讨早期地壳构造演化提供了重要的线索。本文通过对鞍山地区太古代岩石组成、宏-微观构造样式的调查研究和对齐大山、胡家庙子、白家坟剪切变形带的详细解剖,结合数值模拟方法,尝试性探讨了早期地壳构造体制的演化模式。鞍山齐大山和胡家庙子BIF铁矿由富铁BIF与分布于其两侧的贫铁BIF组成,二者呈断层接触,其围岩包括鞍山群樱桃园组和齐大山花岗岩,均发育强烈韧性剪切变形,形成了齐大山-胡家庙韧性剪切带(本文简称齐大山剪切带)。齐大山韧性剪切带内发育的花岗质岩石中长英质矿物塑性拉长特征明显,条带状构造发育,面理向NWW方向陡倾,不对称组构特征和矿物拉伸线理产状指示向NWW的陡倾正滑移剪切作用。且宏观构造样式显示变形岩石距离富铁矿体越近,片理、片麻理、线理越发育,变形程度越强。显微组构分析结果表明,石英波状消光、变形带、膨凸式和亚颗粒旋转重结晶特征;长石塑性拉长、细粒化等一系列中低温显微变形组构特征。石英C轴电子背散射衍射(EBSD)组构分析揭示石英以菱面<a>和底面<a>滑移系为主,岩石经历了中低温非共轴变形。根据矿物的变形行为以及石英的结晶优选方位推测韧性剪切带内岩石的变形温度约为400~500℃,岩石变形特征以位错蠕变为主。有限应变分析结果表明,靠近铁矿带方向,构造岩类型由L=S构造岩过渡为LS构造岩,岩石应变强度呈明显增强趋势。白家坟韧性剪切带位于鞍山齐大山和胡家庙子BIF铁矿西侧,剪切带走向为NNW向,倾向为NEE向。剪切带发育在绿岩带与太古宙花岗岩接触部位。白家坟剪切带内主要发育陈台沟斑状花岗质片麻岩和白家坟片麻岩两大岩石单元,以及少量的强烈变形的鞍山群绿片相变质的绿泥石片岩和千枚岩。S-C组构及矿物旋转残斑均指示剪切带SEE向的陡倾滑剪切特征。岩石显微变形特征表明,石英颗粒普遍存在波状消光、变形纹、变形带等塑性变形特征,以膨凸重结晶和亚颗粒旋转重结晶类型为主。斜长石发育机械双晶、变形带。斜长石残斑多呈σ型旋转眼球构造,指示右行剪切作用,岩石变形温度条件相对较低。有限应变分析显示,陈台沟斑状花岗质片麻岩具有平面-拉伸应变特征,属于L=S型构造岩;白家坟奥长花岗质片麻岩为LS构造岩,表现为一般拉伸应变的变形特征。石英C轴组构分析表明,石英主要发生了底面<a>和菱面<a>滑移,变形温度范围为~450℃。且同样是变形岩石越靠近BIF铁矿,变形越强。综合上述宏-微观构造解析,发现齐大山和白家坟韧性剪切带沿齐大山-西大背BIF铁矿带东西两侧线性对称分布,二者位于绿岩带向斜构造的两翼与花岗岩接触部位,其中白家坟韧性剪切带内岩石面理构造倾向为NEE方向,倾角中等,与绿岩带向斜构造南西翼产状较为一致,矿物拉伸线理向SEE倾伏,倾伏角中等偏大,指示了向斜南西翼一侧向SEE陡倾下滑剪切作用;齐大山韧性剪切带内变形岩石发育向NWW陡倾(~90°)的面理构造,与向斜构造北东翼矿体的产状一致,矿物拉伸线理产状反映了向斜北东翼一侧近向W的陡倾下滑剪切作用,东西两侧相向的陡倾滑运动学特征与绿岩带向形的几何学特征相吻合。因此,推测绿岩带两侧岩石强烈剪切变形很可能与花岗-绿岩带垂向穹脊构造(dome and keel structure)的形成作用相关,岩石变形的运动学特征与垂直构造模式所涉及的底辟作用和拗沉作用相一致,反映了向形绿岩带内的垂向构造作用,韧性剪切作用应发生于花岗-绿岩带垂向穹脊构造的形成过程中,主要表现为密度较轻的花岗质岩石与上覆密度较重的含铁绿岩建造之间存在一定程度的重力不均衡,在区域性地质运动与岩浆作用的驱动下,发生了花岗质岩石向上的底辟作用和含铁建造向下的拗沉作用。为了进一步验证这一构造模型及其发生过程,我们对上述构造模型进行了数值模拟。数值模拟基于前人地质数据资料,结合宏微观地质研究,辅以地球物理资料以及年代学等数据资料,综合构建模型的边界条件,建立地质演化模型。数值模拟采用2D有限差分(I2VIS)并结合marker-in-cell(MIC)技术在中国海洋大学地球科学学院海洋动力学实验室大型计算机组上完成。模拟结果表明,鞍山地区花岗-绿岩带垂向构造成因应受控于新太古代末期大规模的岩浆活动造成的TTG上地壳岩石活化,粘度降低,密度变小,(含铁)绿岩建造与TTG岩石的密度差引起的拗沉作用。同时模拟结果也暗示了太古代垂向构造体制可能是早期地球演化过程中壳-幔物质交换循环的重要机制。鞍山地区花岗-绿岩带整体特征、BIF形态与分布、构造变化规律与世界上其他花岗-绿岩带地体可以类比。垂向构造机制下含铁建造绿岩体向下拗沉过程中伴随的矿体富集特征以及绿岩带向斜构造的形成演化过程为今后沉积变质型铁矿向斜控矿模式的研究以及鞍山地区开展深部找矿的战略部署提供了一定的理论依据。
Abstract
tai gu zhou de ke de gou zao yang shi yi zhi shi de xue jie yan jiu de re dian wen ti zhi yi ,cun zai zhao chui xiang gou zao he shui ping gou zao liang da bu tong de gou zao yan hua ren shi 。wei yu hua bei ke la tong dong yuan de liao dong an shan de ou an fan chu lou tai gu zhou TTGyan ji 、lu pian yan xiang bian zhi de ji xing -zhong suan xing huo shan yan /huo shan chen ji yan 、gui tie zhi chen ji jian zao gou cheng le dian xing de tai gu zhou hua gang -lu yan dai 。ci wai ,hua gang -lu yan dai nei feng fu de gou zao bian xing ji lu ,wei tan tao zao ji de ke gou zao yan hua di gong le chong yao de xian suo 。ben wen tong guo dui an shan de ou tai gu dai yan dan zu cheng 、hong -wei guan gou zao yang shi de diao cha yan jiu he dui ji da shan 、hu jia miao zi 、bai jia fen jian qie bian xing dai de xiang xi jie pou ,jie ge shu zhi mo ni fang fa ,chang shi xing tan tao le zao ji de ke gou zao ti zhi de yan hua mo shi 。an shan ji da shan he hu jia miao zi BIFtie kuang you fu tie BIFyu fen bu yu ji liang ce de pin tie BIFzu cheng ,er zhe cheng duan ceng jie chu ,ji wei yan bao gua an shan qun ying tao yuan zu he ji da shan hua gang yan ,jun fa yo jiang lie ren xing jian qie bian xing ,xing cheng le ji da shan -hu jia miao ren xing jian qie dai (ben wen jian chen ji da shan jian qie dai )。ji da shan ren xing jian qie dai nei fa yo de hua gang zhi yan dan zhong chang ying zhi kuang wu su xing la chang te zheng ming xian ,tiao dai zhuang gou zao fa yo ,mian li xiang NWWfang xiang dou qing ,bu dui chen zu gou te zheng he kuang wu la shen xian li chan zhuang zhi shi xiang NWWde dou qing zheng hua yi jian qie zuo yong 。ju hong guan gou zao yang shi xian shi bian xing yan dan ju li fu tie kuang ti yue jin ,pian li 、pian ma li 、xian li yue fa yo ,bian xing cheng du yue jiang 。xian wei zu gou fen xi jie guo biao ming ,dan ying bo zhuang xiao guang 、bian xing dai 、peng tu shi he ya ke li xuan zhuai chong jie jing te zheng ;chang dan su xing la chang 、xi li hua deng yi ji lie zhong di wen xian wei bian xing zu gou te zheng 。dan ying Czhou dian zi bei san she yan she (EBSD)zu gou fen xi jie shi dan ying yi ling mian <a>he de mian <a>hua yi ji wei zhu ,yan dan jing li le zhong di wen fei gong zhou bian xing 。gen ju kuang wu de bian xing hang wei yi ji dan ying de jie jing you shua fang wei tui ce ren xing jian qie dai nei yan dan de bian xing wen du yao wei 400~500℃,yan dan bian xing te zheng yi wei cuo ru bian wei zhu 。you xian ying bian fen xi jie guo biao ming ,kao jin tie kuang dai fang xiang ,gou zao yan lei xing you L=Sgou zao yan guo du wei LSgou zao yan ,yan dan ying bian jiang du cheng ming xian zeng jiang qu shi 。bai jia fen ren xing jian qie dai wei yu an shan ji da shan he hu jia miao zi BIFtie kuang xi ce ,jian qie dai zou xiang wei NNWxiang ,qing xiang wei NEExiang 。jian qie dai fa yo zai lu yan dai yu tai gu zhou hua gang yan jie chu bu wei 。bai jia fen jian qie dai nei zhu yao fa yo chen tai gou ban zhuang hua gang zhi pian ma yan he bai jia fen pian ma yan liang da yan dan chan yuan ,yi ji shao liang de jiang lie bian xing de an shan qun lu pian xiang bian zhi de lu ni dan pian yan he qian mei yan 。S-Czu gou ji kuang wu xuan zhuai can ban jun zhi shi jian qie dai SEExiang de dou qing hua jian qie te zheng 。yan dan xian wei bian xing te zheng biao ming ,dan ying ke li pu bian cun zai bo zhuang xiao guang 、bian xing wen 、bian xing dai deng su xing bian xing te zheng ,yi peng tu chong jie jing he ya ke li xuan zhuai chong jie jing lei xing wei zhu 。xie chang dan fa yo ji xie shuang jing 、bian xing dai 。xie chang dan can ban duo cheng σxing xuan zhuai yan qiu gou zao ,zhi shi you hang jian qie zuo yong ,yan dan bian xing wen du tiao jian xiang dui jiao di 。you xian ying bian fen xi xian shi ,chen tai gou ban zhuang hua gang zhi pian ma yan ju you ping mian -la shen ying bian te zheng ,shu yu L=Sxing gou zao yan ;bai jia fen ao chang hua gang zhi pian ma yan wei LSgou zao yan ,biao xian wei yi ban la shen ying bian de bian xing te zheng 。dan ying Czhou zu gou fen xi biao ming ,dan ying zhu yao fa sheng le de mian <a>he ling mian <a>hua yi ,bian xing wen du fan wei wei ~450℃。ju tong yang shi bian xing yan dan yue kao jin BIFtie kuang ,bian xing yue jiang 。zeng ge shang shu hong -wei guan gou zao jie xi ,fa xian ji da shan he bai jia fen ren xing jian qie dai yan ji da shan -xi da bei BIFtie kuang dai dong xi liang ce xian xing dui chen fen bu ,er zhe wei yu lu yan dai xiang xie gou zao de liang yi yu hua gang yan jie chu bu wei ,ji zhong bai jia fen ren xing jian qie dai nei yan dan mian li gou zao qing xiang wei NEEfang xiang ,qing jiao zhong deng ,yu lu yan dai xiang xie gou zao na xi yi chan zhuang jiao wei yi zhi ,kuang wu la shen xian li xiang SEEqing fu ,qing fu jiao zhong deng pian da ,zhi shi le xiang xie na xi yi yi ce xiang SEEdou qing xia hua jian qie zuo yong ;ji da shan ren xing jian qie dai nei bian xing yan dan fa yo xiang NWWdou qing (~90°)de mian li gou zao ,yu xiang xie gou zao bei dong yi kuang ti de chan zhuang yi zhi ,kuang wu la shen xian li chan zhuang fan ying le xiang xie bei dong yi yi ce jin xiang Wde dou qing xia hua jian qie zuo yong ,dong xi liang ce xiang xiang de dou qing hua yun dong xue te zheng yu lu yan dai xiang xing de ji he xue te zheng xiang wen ge 。yin ci ,tui ce lu yan dai liang ce yan dan jiang lie jian qie bian xing hen ke neng yu hua gang -lu yan dai chui xiang qiong ji gou zao (dome and keel structure)de xing cheng zuo yong xiang guan ,yan dan bian xing de yun dong xue te zheng yu chui zhi gou zao mo shi suo she ji de de bi zuo yong he ao chen zuo yong xiang yi zhi ,fan ying le xiang xing lu yan dai nei de chui xiang gou zao zuo yong ,ren xing jian qie zuo yong ying fa sheng yu hua gang -lu yan dai chui xiang qiong ji gou zao de xing cheng guo cheng zhong ,zhu yao biao xian wei mi du jiao qing de hua gang zhi yan dan yu shang fu mi du jiao chong de han tie lu yan jian zao zhi jian cun zai yi ding cheng du de chong li bu jun heng ,zai ou yu xing de zhi yun dong yu yan jiang zuo yong de qu dong xia ,fa sheng le hua gang zhi yan dan xiang shang de de bi zuo yong he han tie jian zao xiang xia de ao chen zuo yong 。wei le jin yi bu yan zheng zhe yi gou zao mo xing ji ji fa sheng guo cheng ,wo men dui shang shu gou zao mo xing jin hang le shu zhi mo ni 。shu zhi mo ni ji yu qian ren de zhi shu ju zi liao ,jie ge hong wei guan de zhi yan jiu ,fu yi de qiu wu li zi liao yi ji nian dai xue deng shu ju zi liao ,zeng ge gou jian mo xing de bian jie tiao jian ,jian li de zhi yan hua mo xing 。shu zhi mo ni cai yong 2Dyou xian cha fen (I2VIS)bing jie ge marker-in-cell(MIC)ji shu zai zhong guo hai xiang da xue de qiu ke xue xue yuan hai xiang dong li xue shi yan shi da xing ji suan ji zu shang wan cheng 。mo ni jie guo biao ming ,an shan de ou hua gang -lu yan dai chui xiang gou zao cheng yin ying shou kong yu xin tai gu dai mo ji da gui mo de yan jiang huo dong zao cheng de TTGshang de ke yan dan huo hua ,nian du jiang di ,mi du bian xiao ,(han tie )lu yan jian zao yu TTGyan dan de mi du cha yin qi de ao chen zuo yong 。tong shi mo ni jie guo ye an shi le tai gu dai chui xiang gou zao ti zhi ke neng shi zao ji de qiu yan hua guo cheng zhong ke -man wu zhi jiao huan xun huan de chong yao ji zhi 。an shan de ou hua gang -lu yan dai zheng ti te zheng 、BIFxing tai yu fen bu 、gou zao bian hua gui lv yu shi jie shang ji ta hua gang -lu yan dai de ti ke yi lei bi 。chui xiang gou zao ji zhi xia han tie jian zao lu yan ti xiang xia ao chen guo cheng zhong ban sui de kuang ti fu ji te zheng yi ji lu yan dai xiang xie gou zao de xing cheng yan hua guo cheng wei jin hou chen ji bian zhi xing tie kuang xiang xie kong kuang mo shi de yan jiu yi ji an shan de ou kai zhan shen bu zhao kuang de zhan lve bu shu di gong le yi ding de li lun yi ju 。
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论文作者分别是来自吉林大学的刘昕悦，发表于刊物吉林大学2019-06-25论文，是一篇关于华北克拉通东北缘论文,花岗绿岩带论文,太古代构造论文,拗沉作用论文,数值模拟论文,吉林大学2019-06-25论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自吉林大学2019-06-25论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
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