用户名: 密码: 验证码:
内蒙古大石寨地区超基性岩带的地质特征及构造意义
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
研究区隶属内蒙古兴安盟,大地构造位置位于西伯利亚与华北板块之间,属于古亚洲洋的范围。关于两大板块的闭合位置及时间长期以来存在争议,其中两大板块最终缝合线的位置主要存在两种认识,一是认为沿贺根山带一线,另一种观点则主张沿索伦山-西拉木伦河缝合线。近年来,更多的学者提出贺根山缝合带为华北板块与西伯利亚板块最终的缝合位置。但因中、新生代底层覆盖或岩体破坏,该缝合线的向东延伸不明。关于贺根山缝合带闭合的时间,有人认为在泥盆纪-石炭纪,也有学者主张在晚二叠世。本文通过对内蒙古东部大石寨地区发现的超基性岩带地质、地球化学和年代学特征研究,以期为解决上述相关问题,提供区域研究资料和成果。
     在野外地质填图基础上,结合样品测试和铼锇同位素年代学分析,本文对大石寨超基性岩带的野外地质特征、岩石学特征、岩石地球化学特征及同位素年代学特征进行了研究,取得以下主要成果和认识:
     1,通过野外填图,在内蒙古大石寨地区发现存在构造侵位的超基性岩。他们以断夹块形式产出于二叠纪吴家屯组砂质板岩、粉砂岩及硅质泥岩中。
     2,超基性岩岩石组合为蛇纹石化辉石橄榄岩、纯橄榄岩及橄榄岩。岩石学特征表现出m/f比值均在9左右,为镁质超镁铁岩,具有较高含量MgO含量和Mg#值,在ACM和AFM判别图解中,均落在超镁铁质堆积岩和变质橄榄岩的过渡部位,表明超基性岩为肢解的残余洋壳部分。
     3,稀土元素配分模式显示稍微右倾趋势,稀土总量偏低,轻稀土较富集,表明岩石分异程度不强烈,δEu值为0.88~2.93,表明了早期地幔部分熔融的结晶分异作用;微量元素蜘蛛网图显示富集Cr、Ni、Ti元素贫Nb、Rb元素特征,表明来自于亏损的地幔。
     4,超基性岩Re-Os同位素测年结果表明,其年龄值介于475Ma~313Ma之间,大致反映了初始洋盆的形成时代。
     5,将本区超基性岩与西部邻区贺根山超基性岩对比发现,他们在岩石学、地球化学及同位素年代学方面存在较高的相似性,据此认为大石寨地区超基性岩带可能为贺根山缝合线向东的延伸部分,从而为解决贺根山缝合带东延问题及厘清其中超基性岩组分的形成时代,提供了新的重要证据。
The study area is located in Xing’anmeng, Inner Mongolia,between the NorthChina Craton and the Siberian Craton, and belongs to the Palaeo-Asian Oceanstructural domain. It has been discussed a long time for the age of Paleo-AsianOcean’s closing and the location of suture zone between North China craton andSiberia craton, two scenarios have been proposed for the location: some scholarsthought Hegenshan suture is the two cratons collided location, while the otherscholars thought Suolun mountain-Xilamulun river is the location of the suture. Inrecent years, more and more scholars began to agree Hegenshan suture is the locationof the two cratons collided. However, I t’s eastern part is not well exposed becausecovered by the Cenozoic strata or the rock bodies intrusion. When did the Hegenshansuture formed is also controversial, some scholars proposed it’s in the period fromDevonian to Carboniferous,Others thought it’s in late Permian.In order to solve theabove problems related,This article has done some research about Dashizhaiultrabasic rocks in Inner Mongolia.
     In this paper, on the basis of field geological mapping, combined with theanalysis of the samples in the laboratory, we explored the field geological,petrological, petro-geochemical and isotopic chronology characteristics of theDashizhai ultrabasic rocks, and made the following main achievements:
     1,Through the geological mapping, we have found the adjacent rocks of theseultrabasic rocks which emplaced structurally are sandy slate, siltstone and siliceousmudstone, which belongs to Wujiatun formation of Permian age.
     2,These ultrabasic rocks are composed of serpentinized pyroxene peridotite,dunite and peridotite with m/f about9which belong to magnesia ultramafic rocks,they have high content of MgO and Mg#and all of them locate in the transition zonebetween ultramafic cumulate and metaperidotite in the ACM and AFM figures,suggestting these rocks are remnants of ancient oceanic plate.
     3,The REE distribution patterns show slightly right-dipping, the total amout ofREE are relatively low and the LREE are slightly enriched, suggestting these rocks’ differentiation are not strong, δEu are between0.88and2.93, indicating fractionalcrystallization of the partial melts of the early mantle. Trace element diagrams showthese rocks are enriched in Cr、Ni、Ti and depleted in Nb、Rb, indicating they camefrom depleted mantle.
     4,Through the isotopic dating of Re-Os, we achieved their ages between475and313Ma which was the formation age of the ocean basin.
     5,By the comparition of the petrological, geochemical and isotopic chronologycharacteristics of these ultrabasic rocks with the Hegenshan’ultrabasic rocks in thewest,and they have the very high similarity, we believe that this area is probably theeastward extension of the Hegenshan suture. So this paper provide important newevidence for the problem of the eastern of the Hegenshan suture and clarify the timeof the ultrabasic rocks formation.
引文
A.D. Brandon, J.E. Snow, R.J. Walker, J.W. Morgan, T.D. Mock,190Pt-186Os and187Re-187Ossystematics of abyssal peridotites, Earth Planet. Sci. Lett.2001,177:319~335.
    Chen B,Jahn B M,Wilde S,Xu B.Two contrasting Paleozoic magmatic belts in northern InnerMongolia,China:petrogenesis and tectonic implications. Tectonophysics.2000,(328):157~182.
    Gao Shan, Rudnick R L, Carl son R W, et al. Re–Os evidence for replacement of ancient mantlelithosphere beneath the North China Craton. Earth Planet Sci Let t,2002,198:307~322.
    Kevin W.Burton,Poerre Schiano,Jean-Louis Birck.Osumium isotopedisequilibrium between mantle minerals in a spinel–Iherzolite, Earth Planet. Sci. Lett.1999,172:311~322.
    O. Alard, W.L. Griffin, N.J. Pearson, J.-P. Lorand, S.Y. O'Reilly,New insights into the Re–Ossystematics of sub-continental lithospheric mantle from in situ analysis of sulphides, Earth Planet. Sci. Lett.2002,203:651~663.
    Pearce J A. Supra-subduction zone ophiolites:The search for modern analogues.In: Ophiolite conceptand the evolution of geological thought(eds.Dilek Y&New comb S) Colorado.Geological Society ofAmerican Special Paper,2003,373:269~293.
    Qi L and Zhou MF.Platinum-group elemental and Sr-Nd-Os isotopic geochemistry of PermianEmeishan flood basalts in Guizhou Province,SW China. Chemical Geology,2008,248:83-103.
    Robertson A H F. Overview of the genesis and emplacement of Mesozoic ophiolites in the EasternMediterranean Tethyan region.Lithos,2002,65:1~67.
    R.J. Walker, R.W. Carlson, S.B. Shirey, F.R. Boyd, Os, Sr, Nd, and Pb isotope systematics ofsouthern African peridotite xenoliths implications for the chemical evolution of the subcontinental mantle,Geochim. Cosmochim.1989,(53):1583~1595.
    Robinson, Yang,et al.Geochemical on straints on petrogenesis and crustal accretion of the Hegenshanophiolite,Northern China,Acta Petrol.Sin.,11,Suppl.,1995,112~124.
    Robertson.Development of concepts concerning the genesis and emplacement of Tethyan ophiolitesin the Eastern Mediterranean and Oman regions. Earth-Science Reviews.2004.
    Sengor A M C,Natal`in B A.Paleotectonics of Asia:fragments of a synthesis.In:Yin A.,HarrisonT. M.(Eds).The Tectonic Evolution of Asia,Cambridge University Press,Cambridge,1996:486~641.
    S.H. Richardson, S.B. Shirey, J.W. Harris, R.W. Carlson, Archean subduction recorded by Re–Osisotopes in eclogitic sulphide inclusions in Kimberly diamonds, Earth Planet. Sci.Lett.2001,191:257~266.
    T. Meisel, R.J. Walker, A.J. Irving, J.-P. Lorand, Osmium isotopic compositions of mantle xenoliths:a global perspective, Geochim. Cosmochim.2002,1311~1323.
    Wood D A. The application of a Th-Hf-Ta diagram to problems of tectonomagmatic classification andto establishing the nature of crustal contamination of basaltic lavas of the British Tertiary volcanicprovince. Earth Planet. Sci. Lett.,1980,50:11~30.
    Xiao Wenjiao,Windley B F,Hao Jie,et al.Accretion leading to collisionand the Permian Solonker suture,Inner Mongolia,China:Termination ofthe central Asian orogenic belt.Tectonics.2003.
    Zhang X H,Zhang H F,Tang Y J,et al.Geochemistry of Permian bimodal volcanic rocks fromcentral Inner Mongolia,North China:Implication for tectonic setting and Phanerozoic continental growthin Central Asian Orogenic Belt.Chemical Geology,2008,(249):262~281.
    Zhou J B,Wilde S A,Zhang X Z,et al.The onset of Pacific margin accretion in NE China:Evidencefrom the Heilongjiang highpressure metamorphic belt.Tectonophysics,2009,(478):230~246.
    白文吉,周美付,柴耀楚,胡旭峰.中国基性-超基性杂岩的特征及类型.地质研究所所刊,1989,2:58.
    包志伟,陈森煌,张桢堂.内蒙古贺根山地区蛇绿岩稀土元素和Sm-Nd同位素.地球化学.1994,23(4),339~349.
    陈文,万渔生,李华芹等.同位素地质年龄测定技术及应用.地质学报,2011,85(11):1917~1941.
    代文军.甘肃北山四顶黑山镁铁、超镁铁质岩地球化学特征及其地质意义.甘肃地质.2010,19(2):8~15.
    董显扬,李行.中国超镁铁质岩.北京:地质出版社,1995:65-71.
    段明.内蒙古贺根山地区蛇绿岩的类型及其成矿作用.长春:吉林大学,2007.
    冯光英,刘燊,冯彩霞,贾大成等.吉林红旗岭超基性岩体的锆石U-Pb年龄、Sr-Nd-Hf同位素特征及岩石成因.岩石学报,2011,27(06):1594~1603.
    郭锋,范蔚茗,李超文,苗来成,赵亮.早古生代古亚洲洋俯冲作用:来自内蒙古大石寨玄武岩的年代学与地球化学证据[J].中国科学D辑;地球科学,2009,39(5):569-579.
    贺宏云,宝音乌力吉,杨建军.内蒙古贺根山蛇绿岩地球化学特征及其成因.西部资源.
    金灿海,朱同兴,于元山,周邦国.北羌塘地区冬布勒山基性、超基性岩岩特征及构造意义.矿产勘查.2011,2(1):67~74.
    李双林,欧阳自远.兴蒙造山带及邻区的构造格局与构造演化.海洋地质与第四纪地质.1998,18(3):45~54.
    刘建雄,张彤,许立权.内蒙古好老鹿场地区晚古生代基性-超基性岩的发现及意义[J].地质调查与研究,2006,29(1).
    吕志成,段国正,郝立波,李殿超等.大兴安岭中段二叠系大石寨组细碧岩的岩石学地球化学特征及其成因探讨.岩石学报,2002,18(2):212~222.
    马中平,夏林圻等.蛇绿岩年代学研究方法及应注意的问题.西北地质,2004,37(3).
    马中平,李向林等.阿尔金山南缘长沙沟镁铁-超镁铁质层状杂岩体的发现与地质意义---岩石学和地球化学初步研究.岩石学报,2009,25(04):794~802.
    内蒙古自治区地质矿产局.内蒙古自治区岩石地层,武汉:中国地质大学出版社,1996.
    邱家骧.岩浆岩岩石学.北京:地质出版社,1980,49:49-62.
    任纪舜,陈延愚,牛宝贵等.中国东部及邻区岩石圈的构造演化与成矿.北京:科学出版社.1990.
    邵济安.中朝板块北缘中段地壳演化.北京:北京大学出版社,1991.
    史仁灯.蛇绿岩研究进展、存在问题及思考.地质评论,2005,56(6):681-684.
    邵积东.王惠.张梅等,内蒙古大地构造单元划分及其构造特征.论文天地,2011.
    孙吉明.新疆阿尔金南缘镁铁-超美铁质岩岩石学、岩石地球化学研究.西安:长安大学,2008.
    唐克东.中朝板块北侧褶皱带构造演化及成矿规律.北京大学出版社.1992.
    唐文龙,杨言辰.吉林红旗岭镁铁-超镁铁质岩的地球化学特征及地质意义.世界地质,2007,26(2):164~172.
    王荃.内蒙古中部中朝与西伯利亚古板块间缝合线的确定.地质学报,1986,(1).
    王荃.板块构造与岩浆活动,见:李春昱、郭令智、朱夏等著,板块构造基本问题.北京:地震出版社,1986:221~251.
    文琼英,张川波,汪筱林等.吉林省晚古生代造山带二叠纪移植地体及古地理原型.长城地质学院学报,1996,26(3):265~271.
    吴福元,孙德有.Re-Os同位素体系理论及其应用.地质科技情报,1999,18(3):43~46.
    徐备,陈斌.内蒙古北部华北板块与西伯利亚板块之间中古生代造山带的结构和演化.中国科学(D辑).1997,27(3):227~232.
    杨现力.扎兰屯浅变质岩系地质特征及碎屑锆石年代学研究.长春:吉林大学,2007.
    赵芝.大石寨地区早二叠世大石寨组火山岩的地球化学特征及其构造意义.长春:吉林大学,2008.
    赵磊.华北北缘中部晚古生代镁铁超镁铁岩的岩石地球化学特征及其构造意义[D].北京:北京大学,2008.
    张旗,周国庆.中国蛇绿岩.北京:科学出版社,2001.
    张旗.义敦型镁铁-超镁铁岩的主要特征及其与蛇绿岩的对比.岩石学报,1990,(3):32~40.
    张魁武,沈步明,李达周等.阿拉斯加型超镁铁质岩的岩石化学特征.地质论评,1998,34(4):377~384.
    张魁武,张旗,李达周.阿拉斯加型镁铁-超镁铁杂岩的研究历史和现状.地球科学进展,1990,6:48~51.
    张占飞,谢燕,杜波,韩雪.内蒙古赤峰市巴林左旗下二叠统寿山沟组(P1ss)岩石地层特征.内蒙古科技与经济,2009,24.
    朱云海,潘元明等.蛇绿岩就位机制研究.地质科技情报.2000,19(1):16~18.
    周国庆.蛇绿岩研究新进展及其定义和分类的再讨论.南京大学学报,2008,44(1):12~13.
    周志广,柳长峰,苏尚国,等.内蒙古索伦、乌兰浩特1:25万区域地质调查设计.2009年12月.
    周志广,柳长峰,苏尚国,等.内蒙古索伦、乌兰浩特1:25万区域地质调查2011年工作报告(2011年年报).2011年10月.
    杨芳林,裘有守,田长烈,等.东北地区超基性岩及铬矿资料汇编.1979年9月

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700