共查询到20条相似文献，搜索用时 390 毫秒
1.
板块构造学说的问世,使人们对若干地质现象有了新的认识,作为板块运动特征之一的混杂堆积,是大陆地质工作者需要十分重视的一个对象。 1972年9月李春昱在《试谈“板块构造”》一文中,曾提到西秦岭自甘肃临潭、合作向西到青海玛沁、花石峡一带,可能存在石炭、二迭、三迭系混杂堆积。这里通过目前掌握的有限资料,谈谈混杂堆积的概念以及对其地质意义的初步认识,同时介绍一个可能属于混杂堆积 相似文献
2.
一、节要介绍《美国地质学会会刊》1984年第3期发表了美国斯坦福大学地质系ZH·M·Chang,J·G·Lion和R·G·Colcman的文章《中国板块构造纲要》(以下简称纲要)。《纲要》根据正统的板块构造理论,使用了包括蛇绿混杂体和滑混堆积在内的混杂带、双变质带、钙碱性火山—岩浆弧、海沟型沉积以及某些地区的地震震中与其它地球物理资料等来划分古代和现代活动的板块边界,这是在时空上重建中国板块构造并阐述与构造岩石有关的构造作用的理论依据与地质、地球物理准则。 相似文献
3.
关于雅鲁藏布江断裂带较广泛分布的“混杂堆积”,已经有不少地学专家进行了研究和报道,不同研究者还给予不同的名称。如,有的称之为“构造混杂体”,有的则谓之“滑塌堆积”等。尽管名称各异,但都一致认为是由于“印度板块”向“欧亚板块”俯冲和碰撞的结果,并以此作为雅鲁藏布板块缝合带存在的有力证据之一,从而引起世界地学界的瞩目。作者通过实地调查所取得的一系列资料表明,所谓雅鲁藏布江断裂带“混杂堆积”,或“构造混杂体”、“滑塌堆积”等,它们的形成似乎与所提出的板块构造俯冲和碰撞没有成 相似文献
4.
西秦岭“混杂堆积”及构造发展史 总被引：7，自引：1，他引：6
近年来,国内外不少地学工作者对板块构造进行了大量的研究工作,有人还对隐生宙的板块活动进行了探讨。混杂堆积(Mélange)作为板块构造的重要记录,在滨太平洋及特堤斯构造带极为发育。如美国西部的佛兰西斯堪混杂堆积,我国台湾东部的利吉层混杂堆积,土耳其东 相似文献
5.
双变质带是地球岩石圈板块构造运动产生的重要地质图象,高压低温变质带是大陆上开展板块构造研究的重要目标。它是大洋板块在岛弧和大陆边缘之下俯冲形成的。蓝闪石及其共生矿物的存在是鉴别高压变质岩石产出的标志。板块构造理论问世以来,区域成因岩石学和板块构造矿物学有很大发展。这个理论引进我国十余年来,高压变质带(即高压低温变质带,下同)作为板块构造研究的一个重要方面也取得了成果。本文着重论述我国这方面研究情况,并对蓝闪石、冻蓝闪石的有关问题进行介绍和讨论。 相似文献
6.
双变质带是地球岩石圈板块构造运动产生的重要地质图象,高压低温变质带是大陆上开展板块构造研究的重要目标。它是大洋板块在岛弧和大陆边缘之下俯冲形成的。蓝闪石及其共生矿物的存在是鉴别高压变质岩石产出的标志。板块构造理论问世以来,区域成因岩石学和板块构造矿物学有很大发展。这个理论引进我国十余年来,高压变质带(即高压低温变质带,下同)作为板块构造研究的一个重要方面也取得了成果。本文着重论述我国这方面研究情况,并对蓝闪石、冻蓝闪石的有关问题进行介绍和讨论。 相似文献
7.
本文概述了瑞士地质单元基本特征和地质演化过程。详细记述的内容为:汝拉山侏罗纪地层和构造;磨拉石盆地中海相和陆相磨拉石沉积;海尔微第带的推覆构造、复理石沉积、华力西地块;平宁带中的蛇绿混杂岩、闪光片岩、低温高压变质岩(蓝闪石片岩、榴辉岩),活化基底和盖层推覆体;奥地利阿尔卑斯—南阿尔卑斯仰冲叠覆体中的基底和未受变质的南大陆边缘的浅水碳酸盐岩及断陷盆地内较深水放射虫硅质岩。笔者提出,具有典型意义的瑞士阿尔卑斯碰撞造山带的研究成果对于深入研究我国西部造山带有着重要借鉴作用。 相似文献
8.
9.
大别山北部的变质复理石推覆体 总被引：10，自引：0，他引：10
大别山北部的变质复理石推覆体属华北大陆板块南部的盖层推覆体,主要包括佛子岭群和卢镇关联。其时代主要为震旦纪－早古生代至泥盆纪。变质作用主要为觚闪岩相－绿片岩相,在靠近变质蛇绿混杂岩带附近的部分（佛子岭群）可能普经因卷入变质蛇绿混杂岩带而有过麻粒岩相或榴辉岩相（？）变质作用。变质复理石推覆体中岩石变形强烈,但不同地质变形程度秒等。 相似文献
10.
佛兰西斯科混杂岩(Franciscan melange)沿美国西部的海岸及海岸山脉出露,构成一个近南北向的混杂岩带。这套杂岩起初称为佛兰西斯科杂岩(Franciscan complex)其本身的时代及其和大谷组(Gneat Valley Formation)的关系一直是一个纠缠不清的疑难地质悬案。板块构造说问世之后,许靖华教授首先解开了这个杂岩之谜,认为其形成与板块的俯冲作用有关,是一套典型的混杂岩(melange),也有人将其称为俯冲杂岩(subduction complex)。近年来美国许多著名地质学家曾先后涉足该地区,对佛兰西斯科 相似文献
11.
12.
The Kuyul, Taigonos, and Upper Khatyrka structured serpentinite melanges at the Pacific continental margin of Northeast Asia
considered in this paper are diverse in tectonic setting, age, and geological history. They are characterized by an ordered
internal structure expressed in regular arrangement of rock blocks different in composition. These blocks make up mappable
tectonic sheets deformed into complex, nappe-related folds. Difference in the block composition of particular sheets is often
combined with different composition of serpentinite matrix. The structured melanges of Cape Povorotny (Taigonos Peninsula)
and the Kuyul Terrane were formed during accretion of oceanic complexes to a suprasubduction zone and their subsequent juxtaposition.
The Upper Khatyrka melange comprises oceanic, island-arc, and marginal-sea complexes. The study of structured melanges makes
it possible to ascertain the history of continental accretion and transformation of the oceanic crust. The combination of
ordering and chaotic structure allows us to consider structured melanges as manifestations of nonlinear geodynamics. 相似文献
13.
已有研究实例阐明了蛇绿岩产出的构造环境及构造侵位机制的多样性 ,其中发育完整的蛇绿岩套具有与现代大洋岩石圈剖面相似的四层结构模式 ,它们形成于洋中脊扩张构造环境。由于构造运动使蛇绿岩套肢解 ,构造侵位于大陆造山带缝合线地带 ,沿断裂构造以构造岩片和构造混杂岩产出。蛇绿岩提供了洋壳形成和破坏的重要证据 ,蛇绿岩带或古缝合线是确定造山带中古洋盆存在及陆块边界的直接标志 相似文献
14.
Relationships Between the North China Plate and the Tarim Plate 总被引：3，自引：0，他引：3
Wang Tingyin Wang Jinrong Liu Jinkun D epartment of Geology Lanzhou U niversity Lanzhou GansuWang Shizheng Ningxia Bureau of Geology Mineral Resources Yinchuan Ningxiaand Wu Jiahong Shenyang Institute of Geology Mineral Resources Shenyang Liaoning 《《地质学报》英文版》1994,68(2)
The relationships and boundary between the North China and Tarim plates have been unclear for a long time ; however, the two plates occupy a prominent position in the formation and evolution of the continental lithosphere of China. It is proposed that the Engger Us ophiolitic melange zone discovered recently north of Alaxa is a typical suture between the two plates. The ophiolitic melange zone is composed mainly of a mixture of fragments of ancient oceanic crust and sedimentary rocks of active and passive continental margins. The melange may be divided into tectonic inclusions and matrix. The suture extends northeastwards into the Republic of Mongolia and probably westwards to meet the Altun fault. With the Engger Us ophiolitic melange zone as the boundary the Alaxa area may be divided into two parts: the northern part (AN ) belongs to the Tarim plate, while the southern part (AS) the North China plate. Geological evidence shows that the two plates were amalgamated in the Late Permian or a bit later. 相似文献
15.
16.
西昆仑麻扎构造混杂岩的组成及其地质意义 总被引：5，自引：0，他引：5
西昆仑麻扎构造混杂岩带是1∶25万《麻扎幅》区域地质调查过程中发现并厘定的。岩块主要由火山弧杂岩、与弧相关的沉积建造和外来岩块3部分15个块体组成。各块体之间均为断层接触。基质分布在岩块的边部,主要由构造片岩和糜棱岩等组成。它包含着古洋壳消减过程中的一些重要信息。对构造混杂岩内角闪石英闪长岩进行SHRIMP测年,结果为(338±10）Ma,为早石炭世。麻扎构造混杂带的发现和研究,不仅丰富了麻扎-康西瓦缝合带的内容,而且将该带的演化时限提前到早石炭世,为西昆仑造山带研究提供了基础资料。 相似文献
17.
Alastair Robertson Osman Parlak Timur Ustaömer Kemal Taslı Nurdan İnan Paulian Dumitrica 《Geodinamica Acta》2013,26(3-4):230-293
This paper presents several types of new information including U–Pb radiometric dating of ophiolitic rocks and an intrusive granite, micropalaeontological dating of siliceous and calcareous sedimentary rocks, together with sedimentological, petrographic and structural data. The new information is synthesised with existing results from the study area and adjacent regions (Central Pontides and Lesser Caucasus) to produce a new tectonic model for the Mesozoic–Cenozoic tectonic development of this key Tethyan suture zone.The Tethyan suture zone in NE Turkey (Ankara–Erzincan–Kars suture zone) exemplifies stages in the subduction, suturing and post-collisional deformation of a Mesozoic ocean basin that existed between the Eurasian (Pontide) and Gondwanan (Tauride) continents. Ophiolitic rocks, both as intact and as dismembered sequences, together with an intrusive granite (tonalite), formed during the Early Jurassic in a supra-subduction zone (SSZ) setting within the ?zmir–Ankara–Erzincan ocean. Basalts also occur as blocks and dismembered thrust sheets within Cretaceous accretionary melange. During the Early Jurassic, these basalts erupted in both a SSZ-type setting and in an intra-plate (seamount-type) setting. The volcanic-sedimentary melange accreted in an open-ocean setting in response to Cretaceous northward subduction beneath a backstop made up of Early Jurassic forearc ophiolitic crust. The Early Jurassic SSZ basalts in the melange were later detached from the overriding Early Jurassic ophiolitic crust.Sedimentary melange (debris-flow deposits) locally includes ophiolitic extrusive rocks of boninitic composition that were metamorphosed under high-pressure low-temperature conditions. Slices of mainly Cretaceous clastic sedimentary rocks within the suture zone are interpreted as a deformed forearc basin that bordered the Eurasian active margin. The basin received a copious supply of sediments derived from Late Cretaceous arc volcanism together with input of ophiolitic detritus from accreted oceanic crust.Accretionary melange was emplaced southwards onto the leading edge of the Tauride continent (Munzur Massif) during latest Cretaceous time. Accretionary melange was also emplaced northwards over the collapsed southern edge of the Eurasian continental margin (continental backstop) during the latest Cretaceous. Sedimentation persisted into the Early Eocene in more northerly areas of the Eurasian margin.Collision of the Tauride and Eurasian continents took place progressively during latest Late Palaeocene–Early Eocene. The Jurassic SSZ ophiolites and the Cretaceous accretionary melange finally docked with the Eurasian margin. Coarse clastic sediments were shed from the uplifted Eurasian margin and infilled a narrow peripheral basin. Gravity flows accumulated in thrust-top piggyback basins above accretionary melange and dismembered ophiolites and also in a post-collisional peripheral basin above Eurasian crust. Thickening of the accretionary wedge triggered large-scale out-of-sequence thrusting and re-thrusting of continental margin and ophiolitic units. Collision culminated in detachment and northward thrusting on a regional scale.Collisional deformation of the suture zone ended prior to the Mid-Eocene (~45?Ma) when the Eurasian margin was transgressed by non-marine and/or shallow-marine sediments. The foreland became volcanically active and subsided strongly during Mid-Eocene, possibly related to post-collisional slab rollback and/or delamination. The present structure and morphology of the suture zone was strongly influenced by several phases of mostly S-directed suture zone tightening (Late Eocene; pre-Pliocene), possible slab break-off and right-lateral strike-slip along the North Anatolian Transform Fault.In the wider regional context, a double subduction zone model is preferred, in which northward subduction was active during the Jurassic and Cretaceous, both within the Tethyan ocean and bordering the Eurasian continental margin. 相似文献
18.
The North Penninic basin was a subbasin in the northern part of the Mesozoic Tethys ocean. Its significance within the framework of this ocean is controversial because it is not clear whether it was underlain by thinned continental or oceanic crust. Remnants of the eastern North Penninic basin are preserved in the Alps of eastern Switzerland (Grisons) as low metamorphic "Bündnerschiefer" sediments and associated basaltic rocks which formed approximately 140–170 Ma ago (Misox Bündnerschiefer zone, Middle Jurassic to Early Cretaceous). Nb/U, Zr/Nb, and Y/Nb ratios, as well as Nd–Sr isotopic and REE data of most of the metabasalts point to a depleted MORB-type mantle origin. They have been contaminated by magmatic assimilation of Bündnerschiefer sediments and by exchange with seawater, but do not prove the existence of a subcontinental lithospheric mantle or continental crust beneath the North Penninic basin. This suggests that the studied part of the North Penninic realm was underlain by oceanic crust. Only the metabasalts from two melange zones (Vals and Grava melanges) show a more important contamination by crustal material. Since this type of contamination cannot be observed in the other tectonic units, we suggest that its occurrence is related to melange formation during the subduction of the North Penninic basin in the Tertiary. The North Penninic basin was probably, despite the occurrence of oceanic crust, smaller than the South Penninic ocean where the presence of oceanic crust is well established. Modern analogues for the North Penninic basin could be the transitional zone of the Red Sea or the pull-apart basins of the southernmost Gulf of California where local patches of oceanic crust with effusive volcanism have been described. 相似文献
19.
《Journal of Asian Earth Sciences》2007,29(2-3):215-228
The study of geology, geochemistry, rare earth elements, trace elements, Pb and Sr isotopes of representative ophiolite bodies from four ophiolitic belts in the western Qinghai-Tibetan Plateau, shows that the mantle peridotites of these ophiolites are mainly harzburgite in composition, with minor dunite. They are characterized by high magnesium (MgO) and low aluminum, calcium and alkali oxide contents. Enrichment of light rare earth elements in mantle peridotites may be due to two geological processes: relatively strong partial melting; and later metasomatism by the liquids released during the subduction of oceanic crust. Mantle peridotites are characterized by low contents of the trace elements Sr, Ti and Y and relatively high contents of Rb, Nb, Zr, Hf and Th, similar to metasomatic pyrolite. The isotopic compositions of Sr and Pb show evidence of contamination by a crustal component. All the evidence indicates that the four ophiolite belts in the western Qinghai-Tibetean Plateau have undergone metasomatism by liquids released during the subduction of oceanic crust, suggesting that they were formed in a supra-subduction zone (SSZ) tectonic setting. The mantle peridotites in ophiolite belts located in eastern Qinghai-Tibetan Plateau, e.g. Sanjiang and West Kunlun, may be compared with the Troodos, which is regarded as a typical SSZ complex, having the same geochemical characteristics, i.e. high MgO and LREE-rich. The geochemistry, combined with the occurrence of boninite and adakite rocks, which are associated with subduction magmatism, suggest that ophiolites formed at different times in Qinghai-Tibetan Plateau, including Sanjiang and West Kunlun, are all SSZ-type ophiolites formed in a supra-subduction zone tectonic setting. 相似文献
20.
哈达阳构造混杂岩出露于嫩江黑河构造带之中.根据区域地质背景及构造混杂岩中岩块地质及地球化学特征,划分了基质、原地岩块及异地岩块3部分.基质主要为绿帘黑云绿泥构造片岩.原地岩块主要有绿帘黑云绿泥构造片岩及可能来自海沟外缘缓坡的砾岩.异地岩块主要有角闪石岩、混染闪长岩及变酸性火山岩.角闪石岩及混染闪长岩岩石地球化学特征表明,其形成于与消减作用相关的边缘海扩张环境,而变酸性火山岩具有岛弧钙碱性火山岩特征.上述特征说明,哈达阳构造混杂岩与板块俯冲消减-碰撞作用相关.沿红山梁、哈达阳直达依克特一带出露的古生代地层彼此之间均为断块接触,认为在该沿线存在一条早石炭世末的构造混杂岩带.哈达阳构造混杂岩的发现为正确认识嫩江黑河构造带性质,正确分析构造带结构都具有重要意义. 相似文献