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1.
正The Ordovician (485.4 Ma-443.8Ma) is the longest period of the Paleozoic,which was characterized by a peak of greenhouse climate in Earth history,as well as extreme high sea level (Haq and Schutter,2008;Munnecke et al.,2010),with warm and humid conditions in early-middle period and seawater temperature up to 45℃(Trotter et al.,2008).The carbon cycle fluctuated greatly (Melchin et al.,2013;Cramer et al.,2015) and  相似文献   

2.
正A large area of Late Paleozoic intrusions occursalong the Kalamaili fault in North Xinjiang,which is divided into I-type and A-type granite (Liu et al.,2013),and are the ideal objects for revealing the geological evolution of this region.However,the study of the granodioritic pluton in East Junggar is particularly weak,and previous studies showed different opinions on the Carboniferous tectonic background (e.g.Xu et al.,2013;Zhang  相似文献   

3.
The Kurosegawa belt forms a relatively narrow terrane that can be traced continuously throughout southwest and central Japan. The major constituent continental fragments of the Kurosegawa belt include Early Paleozoic granitic rocks, high-grade metamor-phic rocks, Carboniferous metamorphic rocks (epi-dote-amphibolite facies), Triassic-Early Jurassic metamorphic rocks (pumpellyite-actinolite facies), serpentinites of unknown age, Silurian–Devonian volcanoclastic rocks intercalated with limestones, and Permian–Jurassic shallow marine sediments (e.g., Ichikawa et al., 1956; Maruyama et al., 1984; Faure, 1985; Yoshikura et al., 1990; Aitchison et al., 1991, 1996; Hada et al., 1992, 2001; Isozaki et al., 1992). These diverse rock suites are highly disrupted, form-ing lenticular bodies within the Late Permian accre-tionary complex (AC) which collectively are covered by younger (Cretaceous) marine to brackish water sediments (e.g., Aitchison et al., 1991; Isozaki et al., 1992). We characterize the tectono-stratigraphic ar-chitecture and low-grade metamorphism of the accre-tionary complex preserved in the Kurosegawa belt of the Kitagawa district in eastern Shikoku, Southwest Japan, in order to understand its internal structure, tectono-metamorphic evolution, and assessments of displacement of continental fragments within the complex.  相似文献   

4.
Throughout the Phanerozoic the eastern margin of Gondwana and related fragments such as New Caledonia and New Zealand that are now dispersed from it grew through the addition of ophiolites and associated intra-oceanic island arc assemblages.Exactly how and why this occurred remains controversial with two main competingmodelsreferredtoaseither‘quantum’or‘accordion’tectonics.The quantum model envisages continental growth through the additional of discrete intra-oceanic assemblages analogous to contemporary tectonic settings in Taiwan,Timor and Papua New Guinea(Aitchison and Buckman,2012).The alternative regards eastern Australia as the type example of a different style of convergent plate margin referred to as an‘extensional accretionary orogeny’(Collins,2002).The oldest Phanerozoic ophiolites and intra-oceanic island arc assemblages are of Cambrian age and are widely reported from the Lachlan Fold Belt in the eastern Australian states of Victoria and NSW(Spaggiari et al.,2003;Greenfield et al.,2011).Similar rocks are also known from Mount Read in Tasmania(Berry and Crawford,1988;Crawford and Berry,1992;Mulder et al.,2016),the Weraerai terrane and its correlatives in the New England orogen further east in northeastern NSW(Aitchison et al.,1994;Aitchison and Ireland,1995)and Queensland,the Takaka terrane in NW Nelson,New Zealand(Münker and Cooper,1999)and the Bowers terrane in Northern Victoria Land,Antarctica(Weaver et al.,1984;Münker and Crawford,2000;Rocchi et al.,2011;Palmeri et al.,2012).The Late Ordovician saw the development of the intra-oceanic Macquarie island arc(Glen et al.,1998;Glen et al.,2007).This system contains important economic mineral deposits.The way in which these arcrocks developed and were juxtaposedagainst a surrounding suite of Lachlan Fold Belt,eastern Australia remains the subject of investigation(see Aitchison and Buckman,2012 for discussion).In a similar area,enigmatic rocks of the Tumut ophiolite also crop out(Graham et al.,1996;Belousova et al.,2015).Further to the east in the New England orogeny Siluro-Devonian rocks of the Gamilaroi terrane and it’s along strike correlatives near Mt Morgan in Queensland represent another intra-oceanic island arc assemblage emplaced onto the Gondwana margin in the Late Devonian(Aitchison and Flood,1994;Offler and Murray,2011).The Late Carboniferous-Permian saw development of significant intra-oceanic island arc and ophiolitic complexes remnants of which crop out in New Zealand,eastern Australia,and New Caledonia.These include the Brook Street terrane(Spandler et al.,2005;Mc Coy-West et al.,2014)and Dun Mountain Ophiolite Belt in New Zealand(Coombs et al.,1976;Stewart et al.,2016),the Gympie terrane in southeast Queensland(Waterhouse and Sivell,1987;Sivell and Waterhouse,1988)and the Koh terrane in New Caledonia(Meffre et al.,1996;Ali and Aitchison,2002).The youngest on-land association of ophiolitic and intra-oceanic island arc rocks in the region is of Eocene age.Ultramafic rocks are well exposed in New Caledonia where they structurally overlie continental rocks of Gondwana margin affinity that,in the northeast of the island,have experienced eclogite facies metamorphism(Aitchison et al.,1995).The emplacement of these rocks was a widespread regional event with potentially correlative rocks exposed in Papua New Guinea(Parrot and Dugas,1980)as well as Northland and East Cape in New Zealand(Whattam et al.,2005;Whattam et al.,2008).  相似文献   

5.
<正>1 Introduction The sandstone of Shanxi formation in Upper Paleozoic in the north of Ordos basin is very tight,thin,quick lateral changes and strong heterogeneity.It is a lithologic trap and subtle gas reservoir.It is very difficult to analyze gas enrichment factors and predict high yield zone(Hao et al.,2011;Zhao et al.,2012).The tight sandstone of Shanxi formation in Upper Paleozoic Permian in Linxing area in  相似文献   

6.
This is a review of the formation and tectonic evolution of the continental Asia in Phanerozoic.The continental Asia has formed on the bases of some pre-Cambrian cratons,such as the Siberia,India,Arabia,North China,Tarim,South China,and Indochina,through multi-stage plate convergence and collisional collages in Phanerozoic.The north-central Asia had experienced the expansion and subduction of the Paleo-Asian Ocean(PAO)in the early Paleozoic and the closure of the PAO in the late Paleozoic and early Mesozoic,forming the PAO regime and Central Asian orogenic belt(CAOB).In the core of the CAOB,the Mongol-Okhotsk Ocean(MOO)opened with limited expansion in the Early Permian and finally closed in the Late Jurassic–Early Cretaceous.The south-central Asia had experienced mainly multi-stage oceanic opening,subduction and collision evolution in the Tethys Ocean,forming the Tethys regime and Himalaya-Tibetan orogenic belt.In eastern Asia,the plate subduction and continental margin orogeny on western margin of the Pacific Ocean,forms the West Pacific regime and West Pacific orogenic belt.The PAO,Tethys,and West Pacific regimes,together with Precambrian cratons among or surrounding them,made up the major tectonic and dynamic systems of the continental Asia in Phanerozoic.Major tectonic events,such as the Early Paleozoic Qilian,Uralian,and Dunhuang orogeneses,the late Paleozoic East Junggar,Tianshan and West Junggar orogeneses,the Middle to Late Permian Ailaoshan orogeny and NorthSouth Lhasa collision,the early Mesozoic Indochina-South China and North-South China collisions,the late Mesozoic Mongolia-Okhotsk orogeny,Lhasa-Qiangtang collision,and intra-continental Yanshanian orogeny,and the Cenozoic IndoAsian,Arab-Asian,and West Pacific margin collisions,constrained the formation and evolution of the continental Asia.The complex dynamic systems have left large number of deformation features,such as large-scale strike-slip faults,thrustfold systems and extensional detachments on the continental Asia.Based on past tectonics,a future supercontinent,the Ameurasia,is prospected for the development of the Asia in ca.250 Myr.  相似文献   

7.
正The Appalachian orogen in North America is currently considered to be a Paleozoic accretion-type orogenic belt,or a collage,formed by collision of many ancient blocks between Laurentian and Gondwanan margins (Williams,1979;Williams et al.,1988;van Staal et al.,2007).Recently,major progress has been made in understanding the characteristics and tectonic evolution of the outboard peri-Laurentian and peri-Gondwanan terranes of the Iapetus Ocean (van Staal et al.,2009,2012).  相似文献   

8.
The study area is located in Kawakami-cho, Okayama Prefecture, which is occupied by Lower Carboniferous to Middle Permian Ko-yama Limestone Group (Yokoyama et al., 1979), Permian Yoshii Group (Sano et al., 1987) and Triassic Nariwa Group (Tera-oka, 1959). The Nariwa Group unconformably covers the Paleozoic successions (Otoh, 1985). These succes-sions belong to the Akiyoshi Belt. The Ko-yama Limestone Group is composed mainly of massive limestone, with basic volcanic rocks, acidic tuff and chert. The group was dated by foraminifer and fusu-linid as Lower Carboniferous to Middle Permian (Yo-koyama et al., 1979).  相似文献   

9.
The Hongliuguo-Lapeiquan mélange (Fig. 1) is seen in the Altyn fault belt (AFB), which is a large-scale sinistral strike-slip fault belt in the central Asia and also a part of the north natural boundary of the Qinghai-Tibetan plateau, separating the Tarim basin from the Qaidam basin (Zheng Jiandong, 1988; Avouac et al., 1993; Chalaron et al., 1995; Ge Xiaohong et al., 1998; Cui Junwen et al., 1996, 1997, 1999; Wang Yan et al., 1999). This mélange extends eastward from Hongliuguo thro…  相似文献   

10.
INTRODUCTIONYingen-Ejinaqi basinis locatedin the WulatehouBanner in the west of the Inner Mongolia Autono-mous Region of China ,and covers an area of approxi-mately 122 000 km2( Chen et al ., 2001) . As aMesozoic-Cenozoic depression in Yingen-Ejinaqi ba-sin,the Chagan depression lies in the northeast ofthis basin (Fig.1) .It is about 60 kmlong and 34 kmwide and covers an area of approxi mately 2 000 km2( Wang et al .,2002) .In terms of the basement ter-rain,forms of major structural…  相似文献   

11.
The paper reports the results of petrogeochemical and isotope (Sr-Nd-Pb-Hf) study of the Late Paleozoic granitoids of the Anyui–Chukotka fold system by the example of the Kibera and Kuekvun massifs. The age of the granitoids from these massifs and granite pebble from conglomerates at the base of the overlying Lower Carboniferous rocks is within 351–363 Ma (U-Pb, TIMS, SIMS, LA-MC-ICP-MS, zircon) (Katkov et al., 2013; Luchitskaya et al., 2015; Lane et al., 2015) and corresponds to the time of tectonic events of the Ellesmere orogeny in the Arctic region. It is shown that the granitoids of both the massifs and granite pebble are ascribed to the I-type granite, including their highly differentiated varieties. Sr-Nd-Pb-Hf isotope compositions of the granitoids indicate a contribution of both mantle and crustal sources in the formation of their parental melts. The granitic rocks of the Kibera and Kuekvun massifs were likely formed in an Andean-type continental margin setting, which is consistent with the inferred presence of the Late Devonian–Early Carboniferous marginal-continental magmatic arc on the southern Arctida margin (Natal’in et al., 1999). Isotope data on these rocks also support the idea that the granitoid magmatism was formed in a continental margin setting, when melts derived by a suprasubduction wedge melting interacted with continental crust.  相似文献   

12.
GEOLOGICAL EVOLUTION AND OROGENY OF EAST KUNLUN TERRAIN ON THE NORTHERN QINGHAI—TIBET PLATEAU1 XuZQ ,YangJS ,ZhangJX ,etal.AcomparisonbetweenthetectonicunitsonthesidesoftheAltunsinistralstrike slipfaultandthemechanismoflithosphericshearing[J] :ActaGeologicaSinica,1999,73:193~ 2 0 5(inChinesewithEnglishabstract) . 2 YangJS ,XuZQ ,LiHB ,Wu ,etal.DiscoveryofeclogiteatthenorthernmarginofQaidambasin,NWChina[J] .Chi neseScienceBulletin,1998,4 3…  相似文献   

13.
全球早古生代造山带(Ⅰ):碰撞型造山   总被引:6,自引:0,他引:6  
自新元古代罗迪尼亚超大陆裂解以来,早古生代是板块构造运动活跃时期,具有板块运动速度较快、构造格局不稳定、块体之间相互作用复杂多变等特征,造山带演化极其复杂,导致全球早古生代古大陆重建现今仍较模糊。特别是,早古生代末450~400 Ma存在全球性准同时的造山运动,已经出现俯冲增生、碰撞、陆内3种类型的全球尺度造山带。本文侧重论述全球早古生代碰撞类型造山带的特征,总结典型碰撞造山带最新的年代学、变质、变形和岩浆作用特征及其时空分布。早古生代全球碰撞型造山带主要分布在南半球的泛非造山带和北半球的加里东期造山带,分别与南方冈瓦纳大陆和北方劳俄古陆的初步集结密切相关,早古生代碰撞造山主要体现在大陆块之间的碰撞作用为特征。这些早古生代碰撞造山带具有近似的碰撞年龄,大致相同的演化过程。其中,南方大陆主体碰撞完成于540 Ma,而北方大陆主体集结完成于420 Ma,从全球构造意义上可能意味着全球一个420~400 Ma的超大陆初步形成。  相似文献   

14.
In the Gyirong and Nyalam areas, a massive amount of augen gneisses are extensively exposed in the middle Himalayan orogen. They consist of quartz, K-feldspar, plagioclase, biotite and minor muscovite. Zircons from augen gneisses have magmatic rims indicated by concentric oscillatory zoning. LA-ICP-MS zircon U-Pb dating gave weighted mean ages of (488.5±1.1) Ma (MSWD=0.6)、(475.1±0.7) Ma (MSWD=1.5) and (468.1±2.5) Ma (MSWD=4.2), hinting early Paleozoic magmatism in the Greater Himalayan Crystalline complex (GHC). The data in this study and other published geochronological results of Cambrian-Ordovician magmatites demonstrated that early Paleozoic orogenesis existed in the Himalayas. Early Paleozoic tectonic events preserved in Himalayas are well compared with the contemporaneous ones in the Lhasa terrane, Qiangtang terrane, Baoshan terrane and Tengchong terrane located in the south and southeast of Tibet Plateau. Integrating previous studies, we suggested an Andean-type orogeny corresponding to dynamic adjusting of the plates by subduction of the Proto-Tethys Ocean lithosphere along the northern margin of Gondwana, instead of Pan-African orogeny that was characterized by the continent-continent collisions during Gondwana assembly.  相似文献   

15.
南华夏造山带构造演化的新证据   总被引:40,自引:6,他引:40       下载免费PDF全文
李继亮  许靖华 《地质科学》1989,2(3):217-225
华南的大地构造有两种解释,一种可称为加里东造山模式,另一种可称为华南阿尔卑斯模式。前者认为华南是一个早古生代造山带,其后便成为准地台。中生代时受到活化导致盖层与基底的褶皱、断裂、岩浆作用和成矿作用。但这个模式不能解释许多地质事实。 本文继许靖华等(1987)的模式之后,给出了一些新证据,其中包括皖赣蛇绿混杂岩、蓝田、西山和乐平构造窗以及庐山飞来峰。这些证据为华南的三叠纪造山作用和构造演化模式提供了强有力的支持。  相似文献   

16.
邓胜徽 《现代地质》1998,12(2):168-172,T001
内蒙古赤峰市东南部的平庄—元宝山盆地杏园组和元宝山组为含煤地层,时代归属有争议。杏园组所产6属7种植物,主要为早白垩世的常见分子,反映时代为早白垩世早期,相当于凡兰吟期到欧特里夫早期,与辽西的沙海组、内蒙古霍林河盆地霍林河组下含煤段和海拉尔盆地大磨拐河组可以对比。元宝山组含19属21种,主要为阜新植物群的常见代表,说明其时代为早白垩世中期,相当于欧特里夫晚期到巴雷姆期,可同辽西的阜新组、内蒙古的霍林河组上段和伊敏组相对比。  相似文献   

17.
新元古代江南造山带远离晚中生代活动大陆边缘,是研究华南地区新元古代至早中生代多期造山作用的理想对象。文章通过对江南造山带东段沉积建造、岩浆活动、构造变形以及同位素年代学数据的综合分析,总结了其晋宁期、广西期以及印支期造山作用的特征。江南造山带东段在晋宁期经历了南北两侧大洋俯冲和两期碰撞造山作用。新元古代早期(880~860 Ma)双溪坞岛弧与扬子陆块东南缘发生弧-陆碰撞作用,形成淡色花岗岩、高压蓝片岩、NNE向褶皱-逆冲构造以及弧后前陆盆地。新元古代中期(约850 Ma),扬子陆块北缘开始发育由北向南的大洋俯冲。随着俯冲作用的进行,弧后盆地发生关闭,扬子陆块与华夏陆块发生陆-陆碰撞并形成新元古代(820~810Ma)江南造山带,导致近E-W走向褶皱-逆冲构造、韧性变形以及过铝质花岗岩的发育。江南造山带东段在约810Ma开始发生后造山垮塌和裂谷作用,以发育南华纪早期(805~750 Ma)花岗岩、中酸性火山岩、基性岩以及裂谷盆地为特征。江南造山带东段万载—南昌—景德镇—歙县断裂带以南地区卷入了华南广西期造山作用,发育近E-W走向由南向北的逆冲构造(465~450 Ma)、NNE向正花状构造(449~430 Ma)以及后造山近E-W走向韧性走滑剪切带(429~380 Ma)。印支期造山作用导致了NNE向褶皱-逆冲构造和花岗岩的发育,并奠定了江南造山带东段的基本构造面貌。  相似文献   

18.
兴蒙造山带属于中亚造山带的东段,关于其演化过程存在两种主要观点:一种观点认为它是由古亚洲洋经历整个古生代的连续俯冲-碰撞过程后在早三叠世形成;另一种观点则认为古亚洲洋在晚泥盆世之前就通过俯冲-碰撞过程闭合,形成早-中古生代造山带,随后在石炭-二叠纪又经历了从陆内伸展到再次闭合的过程,并形成陆内造山带。蒙古国东南部扎门乌德地区出露各类古生代沉积岩和岩浆岩,可以为解决上述争议提供典型研究实例。本文通过沉积学、年代学和地球化学等多种手段综合研究,取得以下研究成果:(1)根据年代学和岩性特征,在该地区识别出三类古生代岩石组合,第一类是以黑云母二长花岗岩为代表的中志留世侵入岩,第二类是中泥盆世大套的粗碎屑岩-火山岩沉积旋回,第三类是不整合地沉积于早期造山带之上的二叠纪巨厚火山-沉积岩系。这三类岩石组合分别属于俯冲阶段的大陆边缘岛弧带岩浆岩、碰撞造山后期的上叠盆地以及叠加在早期造山带岩石圈之上的晚古生代陆内伸展时期的裂谷盆地的沉积。(2)利用研究区所有古生代碎屑锆石和岩浆岩全岩资料,揭示了该地区古生代时期地壳厚度变化趋势如下:500~425Ma的俯冲-碰撞过程造成地壳加厚;425~375Ma的碰撞造山后伸展过程使地壳变薄;375~350Ma地壳再次加厚,可能与造山带物质堆叠有关;350~275Ma地壳再次减薄,对应于广泛而强烈的晚石炭世-早二叠世火山岩,证明此时期岩浆活动的构造背景是区域伸展而不是挤压作用。(3)根据研究区出现的三类岩石组合特点,结合研究区以南的艾力格庙地区已有的研究成果,可以划分出五个早-中古生代造山带构造单元和两个叠加其上的晚古生代陆内造山带构造单元,揭示蒙古国扎门乌德地区经历了早-中古生代加积造山带和晚古生代陆内造山带等两个构造演化过程。本文研究为认识兴蒙造山带的两阶段构造发展提供了新资料。  相似文献   

19.
从沉积建造分析入手,通过对区内晚古生代—早中生代火山岩组合的构造属性识别,认为区内晚古生代—早中生代构造演化是一个连续的过程,它奠定了该区的基本构造格局,也是金与铜多金属矿产的主要成矿时期;晚古生代—早中生代发育的双岩浆弧是在同一动力学机制下不同阶段形成的造山岩浆弧:陆缘的钙碱性岩浆弧和陆内的高钾钙碱性岩浆弧。晚古生代—早中生代构造岩浆旋回可以划分为2个阶段,早期的俯冲造山阶段形成了与蛇绿岩有关的火山岩类和弧火成岩类,晚期的大洋闭合和碰撞造山阶段则形成了钾玄岩系列火山岩。  相似文献   

20.
库鲁克塔格是新疆前寒武纪出露较全的地区,然而该区区域成矿规律研究程度非常低.通过对研究区已有资料进行总结分析,系统阐述研究区矿床类型,并对其成矿系列进行划分.研究区从太古代到早古生代形成了7个主要的岩浆构造演化阶段:古太古代陆核形成阶段(3.3~3.0 Ga)、新太古代-古元古代陆壳增生改造阶段(2.6~2.3 Ga)、古元古代中晚期陆壳改造阶段(2.1~1.8 Ga)、中元古代晚期-新元古代早期造山运动阶段(1.1~0.86 Ga)、新元古代中期后碰撞伸展阶段(830~800 Ma)、新元古代中晚期陆内裂解阶段(770~600 Ma)和早古生代造陆运动阶段.成矿作用主要发生在古元古代、新元古代及早古生代.依据各构造演化阶段、含矿建造特征及矿床成因特征,将库鲁克塔格成矿作用类型总结为以下6个主要成矿系列,即形成于古元古代陆壳增生改造环境下的Fe-P-Cu-Au系列、新元古代俯冲碰撞环境下的Cu-Au系列、新元古代后碰撞环境下的Cu-Mo-Au-Fe-P-REE系列、新元古代裂解环境下的Cu-Ni系列、早古生代沉积盆地中Ag-V-Mo-Au-U-P系列和早古生代俯冲岛弧环境下的Cu-Au系列.   相似文献   

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