http://www.sciencedirect.com/science/article/pii/S1674987113001606     

Inna Safonova 《地学前缘(英文版)》2014,5(4):537-552

The paper reviews previous and recently obtained geological, stratigraphic and geochronological data on the Russian-Kazakh Altai orogen, which is located in the western Central Asian Orogenic Belt （CAOB）, between the Kazakhstan and Siberian continental blocks. The Russian-Kazakh Altai is a typical Pacific-type orogen, which represents a collage of oceanic, accretionary, fore-arc, island-arc and continental margin terranes of different ages separated by strike-slip faults and thrusts. Evidence for this comes from key indicative rock associations, such as boninite- and turbidite （graywacke）-bearing volcanogenic-sedimentary units, accreted pelagic chert, oceanic islands and plateaus, MORB-OIB-protolith blueschists. The three major tectonic domains of the Russian-Kazakh Altai are： （1） Altai-Mongolian terrane （AMT）; （2） subduction-accretionary （Rudny Altai, Gorny Altai） and collisional （Kalba-Narym） terranes; （3） Kurai, Charysh-Terekta, North-East, Irtysh and Char suture-shear zones （SSZ）. The evolution of this orogen proceeded in five major stages： （i） late Neoproterozoic-early Paleozoic subduction-accretion in the Paleo-Asian Ocean; （ii） Ordovician-Silurian passive margin; （iii） Devonian-Carboniferous active margin and collision of AMT with the Siberian conti- nent; （iv） late Paleozoic closure of the PAO and coeval collisional magmatism; （v） Mesozoic post-collisional deformation and anarogenic magmatism, which created the modern structural collage of the Russian- Kazakh Altai orogen. The major still unsolved problem of Altai geology is origin of the Altai-Mongolian terrane （continental versus active margin）, age of Altai basement, proportion of juvenile and recycled crust and origin of the middle Paleozoic units of the Gorny Altai and Rudny Altai terranes.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987113001333     

loanBalintoni  ConstantinBalica  MihaiN  Ducea  Horst-PeterHann 《地学前缘(英文版)》2014,5(3):395-411

The basement of the Romanian Carpathians is made of Neoproterozoic to early Paleozoic periGondwanan terranes variably involved in the Variscan orogeny,similarly to other basement terrains of Europe.They were hardly dismembered during the Alpine orogeny and traditionally have their own names in the three Carpathian areas.The Danubian domain of the South Carpathians comprises the Dragsan and Lainici-Paius peri-Amazonian terranes.The Dragsan terrane originated within the ocean surrounding Rodinia and docked with Rodinia at ~800 Ma.It does not contain Cadomian magmatism and consequently it is classified as an Avalonian extra-Cadomian terrane.The Lainici-Paius terrane is a Ganderian fragment strongly modified by Cadomian subduction-related magmatism.It is attached to the Moesia platform.The Tisovita terrane is an ophiolite that marks the boundary between Dragsan and Lainici-Paius terranes.The other basement terranes of the Romanian Carpathians originated close to the Ordovician NorthAfrican orogen,as a result of the eastern Rheic Ocean opening and closure.Except for the Sebes-Lotru terrane that includes a lower metamorphic unit of Cadomian age,all the other terranes(Bretila,Tulghes,Negrisoara and Rebra in the East Carpathians,Somes,Biharia and Baia de Aries in the Apuseni mountains,Fagaras,Leaota,Caras and Pades in the South Carpathians) represent late Cambrian—Ordovician rock assemblages.Their provenance,is probably within paleo-northeast Africa,close to the Arabian-Nubian shield.The late Cambrian-Ordovician terranes are defined here as Carpathian-type terranes.According to their lithostratigraphy and origin,some are of continental margin magmatic arc setting,whereas others formed in rift and back-arc environment and closed to passive continental margin settings.In a paleogeographic reconstruction,the continental margin magmatic arc terranes were first that drifted out,followed by the passive continental margin terranes with the back-arc terranes in their front.They accreted to Laurussia during the Variscan orogeny.Some of them(Sebes-Lotru in South Carpathians and Baia de Aries in Apuseni mountains) underwent eclogite-grade metamorphism.The Danubian terranes,the Bretila terrane and the Somes terrane were intruded by Variscan granitoids.  相似文献   

Magmatic activity and its geological significance in Early Jurassic in Mangui area of Inner Mongolia     

LI Zhonghui  LI Yang  LI Ruijie  LI Kai 《中国地质调查》2014,7(5):54-65

By investigating the U-Pb zircon isotope geochronology and petrogochemistry of the major magmatic rocks in Mangui area, the authors in this paper discussed the forming era, tectonic background and geological significance. A large amount of intrusive rocks and a small amount of medium-acid volcanic rocks in Early Jurassic were found in this area. U-Pb dating by LA-ICP-MS method shows that the ages are from (199±1)Ma to (184±1)Ma and the rock types can be divided into fine-medium-grained quartz diorite, medium-grained granodiorite, fine-medium-grained monzogranite, medium-fine-grained macrophenocryst monzogranite, rhyolite, dacite and andesite, which didn’t ouur in Neoprotezoic-Paleozoic period as previous researchers thought, revealing the tectonic and magmatic activities during the Early Mesozoic period. The geochemical results show that the rocks are Ⅰ-type magmatic rocks of subluminous-peraluminous high-K calc-alkaline series. The fractionation between light and heavy rare-erath elements((La/Yb)_N= 3.42~32.96) and the Eu depletion degree is not complied with the evaluation from basic to acidic. The large ion lithophile element Ba is relatively rich and Rb, Sr are relatively delicient. The high field strength elements Th and U are relatively rich and Nb, Ti, Y are relatively deficient. The magma origin and tectonic setting show that quartz diorite and medium-fine-grained macrophenocryst monzogranite come from crust-mantle mixed magma, while the medium-acid volcanic rocks, granodiorite and fine-medium-grained monzogranite are from the partial melting of crustal materials, whose formation is connected with the evolution of Mongol-Okhotsk Suture Zone. The geology and geochemistry of the Early Mesozoic magmatic rocks indicate that the middle part of Mongol-Okhotsk Ocean might begin subduction at the end of the middle Triassic and close the Early Jurassic. The peak collision might take place at the Early Jurassic, not in the Late Triassic as previous thought. The Mohe over-thrust nappe system might form in the remote effect of southward extrusion during the closing process of the eastem part of Mongol-Okhotsk Ocean. The middle and eastern Mongol-Okhotsk Ocean closing age is of great importance to reveal the basin-range tectonic formation during the Middle Jurassic to the Late Cretaceous in Northeast China.  相似文献   

地壳所与多省地震局开展科技交流与合作活动     

《地壳构造与地壳应力》2014,(1)

正1.与河北省地震局签订科技交流与合作框架性协议2014年4月2日,地壳应力研究所与河北省地震局在河北省怀来签订了科技交流与合作框架协议,并举行了中国地震局地壳应力研究所地下流体野外观测试验基地挂牌仪式。地壳所谢富仁所长、陈虹副所长、河北省地震局孙佩卿局长、高景春副局长,以及双方相关处室负责人和专家出席了会议。  相似文献   

从地壳上地幔构造看大陆碰撞带岩石圈的克拉通化   总被引：1，自引：0，他引：1  

杨文采  于常青 《地质论评》2014,60(4):721-740

本篇讨论超级大陆汇聚后逐渐变为克拉通或扩大克拉通的作用过程,即指经及大陆碰撞地体汇聚后新形成的大陆块逐渐转变为刚性克拉通的作用过程。增生大陆岩石圈的克拉通化的作用后果,包括大陆地壳密度的增加,岩石圈地幔的增厚和大地热流值的下降,使大陆岩石圈逐渐刚性强化。大陆碰撞后形成的大陆块必须经过克拉通化的过程,才能逐渐成为刚性克拉通。作用过程主要包括:①上地壳沉积碎屑岩石结晶岩化和中地壳岩石角闪岩化;②下地壳岩石基性化;③大陆碰撞带下凹莫霍面的磨平;④岩石圈地幔底侵加厚形成陆根。从大陆碰撞带转变为克拉通的过程也是岩石圈地幔不断增厚而地壳缓慢变硬变冷的过程。这个过程包含以下作用:区域变质作用,交代作用和岩石圈幔源岩浆的底侵。这个过程时间尺度比碰撞造山作用大一个级次。长期的底侵作用使地壳岩石密度和强度不断加大,改变岩层的矿物成分和局部结构。当大陆岩石圈克拉通化到一定程度之后,由于下方软流圈的热能供应逐渐减缓,使岩石圈地温梯度缓慢下降,最终结果会形成大陆根。由于显生宙大陆碰撞带岩石圈强度弱,大陆碰撞时更容易造成岩石圈变形,因此大陆碰撞的板内效应主要发生在大陆内的显生宙碰撞带。显生宙大陆碰撞带如果再次受到大陆碰撞板内效应的作用,其克拉通化的过程必然会推迟。  相似文献   

从地壳上地幔构造看洋陆转换作用     

杨文采  宋海斌 《地质论评》2014,(1)

根据近年来全球地壳上地幔探测的成果,分析了洋陆转换、地壳和岩石圈加厚的作用过程。洋陆转换作用可分为以下五个演化阶段:①同大洋扩张期的地壳增厚;②海沟发生与早期俯冲;③俯冲带成熟与沟弧盆体系形成;④俯冲带汇聚和位移;⑤陆—岛碰撞和陆壳连接。同大洋扩张期的地壳增厚作用指发生在被动大陆边缘的地质作用。包括沉积作用,岩浆底侵作用,下地壳和岩石圈地幔压裂,形成海沟等。海沟形成后陆缘转变为主动大陆边缘,大地构造机制转换为板块俯冲作用。成熟期的洋—陆转换作用特征是海盆扩张和板块俯冲造成的洋壳缩短取得平衡。弧后盆地和弧后边缘海的打开,表明俯冲带进入完全成熟的阶段。洋脊俯冲之后过成熟期的洋—陆转换作用,其特征是海盆逐渐缩小而且板块俯冲带汇聚。这里既有密集的俯冲带又有短期打开的边缘海岭;俯冲带不断位移,既可后撤也可前冲;俯冲板块经常发生断裂和拆沉。过成熟期的板块俯冲结果是边缘海微板块的萎缩。经过陆—岛碰撞,岛弧地壳增厚,与大陆板块连为一体,成为大陆内部的一个构造单元,即显生宙的"古洋—陆转换带"。  相似文献   

滇中新元古代裂谷盆地充填序列及演化模式:对Rodinia超大陆裂解的响应   总被引：5，自引：0，他引：5  

崔晓庄  江新胜  王剑  卓皆文  伍皓  熊国庆  陆俊泽  邓奇  江卓斐 《沉积学报》2014,32(3):399-409

以滇中新元古代裂谷盆地沉积充填为研究对象,开展了系统的沉积学和盆地分析研究。结果表明,滇中新元古代裂谷盆地具有4个充填序列,分别代表盆地的4个发展阶段。其中,序列I为柳坝塘组及陆良组下段,沉积时限为820~800 Ma,属低密度浊流和深水饥饿沉积,代表裂谷盆地的快速沉降阶段;序列II为澄江组、陆良组上段及牛头山组,沉积时限为800~725 Ma,属扇三角洲-湖泊沉积,代表裂谷盆地的成熟发展阶段;序列III为南沱组,沉积时限可能为725~635 Ma,属大陆冰川沉积,代表裂谷盆地开始向被动大陆边缘盆地转换的阶段;序列IV主要为陡山沱组,沉积时限为635~551 Ma,属潮坪沉积,为裂谷盖地层。进一步研究揭示,滇中新元古代裂谷盆地由幼年期分布局限的小型同向半地堑盆地群演化为成熟期统一的大型半地堑盆地,属上叠滑脱盆地。综合研究证实,滇中新元古代裂谷盆地应为陆内裂谷盆地,是Rodinia超大陆裂解的产物。  相似文献   

喜马拉雅造山带东构造结拉布拉多期和格林威尔期造山作用的记录   总被引：6，自引：6，他引：0  

王誉桦  曾令森  高利娥  张立飞  侯可军 《岩石学报》2014,30(8):2241-2252

位于喜马拉雅东构造结西北部的南迦巴瓦复合体,是构造应力最强、隆升和剥蚀最快、新生代变质和深熔作用最强的地区。为厘定该地区早期的变质岩浆作用,本文对南迦巴瓦复合体北部的花岗片麻岩和混合岩进行了岩石学和年代学研究。花岗片麻岩原岩为富钾的偏铝质花岗岩,具有岩浆弧花岗岩的成分特征。花岗片麻岩中的锆石具有岩浆锆石的环带结构,记录了487.9±1.6Ma的一期构造岩浆事件;混合岩的锆石具有明显的核-边结构,核部和边部的不协和线交点年龄分别为1559±13Ma、1154±12Ma。对比印度大陆东部的西隆高原、东高止造山带,发现三者都经历了拉布拉多期、格林威尔期以及泛非期的造山作用。因此,我们认为喜马拉雅东构造结与这两个地区密切相关,可能是他们向北的延伸,这三者可能组成统一的印度大陆东部造山带,一起经历了哥伦比亚超大陆、Rodinia和冈瓦纳超大陆的聚合与裂解过程。  相似文献   

西秦岭印支期高Sr/Y花岗岩类的成因及动力学背景——以同仁地区舍哈力吉岩体为例   总被引：5，自引：4，他引：1  

黄雄飞  莫宣学  喻学惠  李小伟  杨梦楚  罗明非  和文言  于峻川 《岩石学报》2014,30(11):3255-3270

西秦岭印支期花岗岩类分布十分广泛,形成时代集中于248~234Ma和224~211Ma两个阶段.其中,夏河岩体(248~238Ma)和温泉岩体(223~216Ma)的部分样品被厘定为埃达克岩(Sr>400×10^-6,Yb<2×10^-6),指示陆壳厚度大于50km.本文对西秦岭同仁地区舍哈力吉岩体进行了锆石U-Pb定年、岩石学、地球化学和Sr-Nd同位素研究.舍哈力吉岩体主要由石英二长岩组成,同时含有许多暗色镁铁质微粒包体(MME).寄主岩中发育少量的钾长石巨晶,并且部分巨晶具有环斑结构.舍哈力吉石英二长岩化学成分比较均一,而且也显示出类似埃达克岩的一些地球化学特点,如富SiO₂(66.07%~67.52%)和Al₂O₃(14.85%~15.95%),高Sr(560×10^-6~692×10^-6),低Y(11.4×10^-6~12.9×10^-6)和Yb(0.99×10^-6~1.09×10^-6),并具有较高的(La/Yb)_N比值(27.8~34.3)和微弱的负Eu异常(δEu=0.77~0.95).锆石U-Pb测年结果为234.1±0.5Ma,表明其形成于印支早期.岩石为偏铝质、高钾钙碱性系列且K₂O/Na₂O>1,高Mg^#(59~60)、Cr(69.1×10^-6~81.2×10^-6)和Ni(31.6×10^-6~36.1×10^-6),以富集大离子亲石元素(Rb、Ba、Th、U)而相对亏损高场强元素(Nb、Ti、P)为特征,(⁸⁷Sr/⁸⁶Sr)_i=0.7075~0.7077,ε_Nd(t)=-6.3~-6.1,亏损地幔模式年龄为1.25~1.33Ga.舍哈力吉石英二长岩起源于石榴角闪岩相古老下地壳的部分熔融,之后经历了壳幔岩浆混合作用和以斜长石为主的分离结晶作用.寄主岩的环斑结构和相对一致的地球化学特征,很可能是高温幔源熔体对壳源富钾高黏度岩浆改造所导致的晶粥快速再活化的结果.西秦岭在印支早期可能并未经历显著的地壳加厚过程.西秦岭印支早期花岗岩类形成于活动大陆边缘局部伸展环境,可能与古特提斯洋壳俯冲极性的改变有关.  相似文献   

准噶尔中东部地区深部电性结构电磁探测          下载免费PDF全文

田少兵  蔡建超  胡祥云  李建慧  曾思红  徐珊 《地球科学》2014,39(5):620-628

为了解准噶尔盆地深部构造特征,综合利用“深部探测技术与试验研究(SinoProbe)”项目在准噶尔盆地45°N 88°E处建立的大地电磁标准点实测资料,应用非线性共轭梯度法(NLCG)对该测站两条短剖面进行二维反演,结合新疆准噶尔盆地区域地质资料,对该地区地层电性结构进行了初步分析,发现准噶尔盆地中东部地区地下结构具有很好的电性分层.与现有地质资料相结合,分析发现其电性分层与地壳分层具有较好的对应.根据岩石层电导性推断:研究区域莫霍面埋深在46 km附近,岩石圈厚度在100 km左右.研究结果对准噶尔中东部地区深部地壳结构的认识具有一定的参考价值.   相似文献