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东亚大陆和西太平洋之间,存在着全球规模的边缘海-岛弧系。对于边缘海-岛弧系的成因,国内外学者众说纷云。我国大地构造学家张文佑(1983)简洁地概括为“拉张造海、挤压造陆”。本文对大量的有关边缘海的重、磁、地震、钻井和大地构造背景等资料综合分析之后,认为边缘海具有与大洋不同的演化旋回,而与陆缘地堑的演化阶段密切相关。 相似文献
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长江源地区近南北走向的地堑构造是该区现今最为显著的构造现象,也是青藏高原迄今发现的同类构造发育的最北部地区.长江源地区地堑构造包括温泉、常错、当拉错纳玛和沱沱河4个规模较大的近南北向地堑.断层年代学和断陷盆地沉积作用研究结果表明,研究区伸展变形至少自中新世末-上新世初就已开始,对长江源地区现今的地貌格局、水系型式具有显著的制约作用.长江源区主要水系是沿南北走向的地堑构造和正断层侵蚀发育而成的.青藏高原新生代伸展地堑构造是高原经历早期地壳强烈缩短变形之后,在深部动力学机制作用下快速隆升的产物. 相似文献
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长江源区新生代地堑的构造特征与形成机制 总被引:1,自引:2,他引:1
长江源地区近南北走向的地堑构造是该区现今最为显著的构造现象,也是青藏高原迄今发现的同类构造发育的最北部地区.长江源地区地堑构造包括温泉、常错、当拉错纳玛和沱沱河4个规模较大的近南北向地堑.断层年代学和断陷盆地沉积作用研究结果表明,研究区伸展变形至少自中新世末-上新世初就已开始,对长江源地区现今的地貌格局、水系型式具有显著的制约作用.长江源区主要水系是沿南北走向的地堑构造和正断层侵蚀发育而成的.青藏高原新生代伸展地堑构造是高原经历早期地壳强烈缩短变形之后,在深部动力学机制作用下快速隆升的产物. 相似文献
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劈理现象的研究从D.沙尔普开始,已有百余年的历史。关于劈理形象的描述、分类与成因方面的一些基本看法,在本世纪初期及更早一些时候就提出来了(Sorby H. C. 1856; Becker G. 1904; LeithC. K. 1905; Becke F. 1913)。以后,仍有不少构造地质工作者继续不断地进行劈理的研究,提出一些补充资料和分类与成因的看法(如Sander B. 1930; Closs E. 1947; Hoeppener R. 1955; de Sitter L.U. 1956; Knill J. K. 1960; Gonzalez-Bonorino F. 1960; Turner F. J. & Weiss L. E. 1963)。 相似文献
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笔者以冈底斯构造带内部近南北向发育的多桑地堑带为代表,简述了多桑地堑带构造的组成及基本构造特征。根据该地堑两侧断隆山的发育特征及磷灰石、锆石裂变径迹测年结果,推断地堑的断陷活动时期始于中新世,直至第四纪仍有活动,对上新世-第四纪沉积起明显的控制作用。多桑地堑带的形成可能为前期南北向受力不均而产生共轭x节理,后期南北向挤压的持续进行使地壳隆升,当隆升到达一定程度后造成重力塌陷及下地壳物质的侧向流动产生纵向拉张作用,此时前期形成的共轭x节理追踪并部分贯通,最终形成多桑地堑,而横向上的区域断裂则可能控制地堑各区段拉伸宽窄的变化和沉降的不均匀性。 相似文献
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大地规模的断裂体系很早以前就引起了构造地质学家们的注意。本世纪初W.H.霍布斯(Hobbs)指出地壳具有块断性质。继而,1938年R.A.臧德尔(Sonder),1948年H.克鲁斯(Cloos)和B.B.布罗克(Brock)等阐明了地壳具有区域性构造断裂体系。特别是R.A.臧德尔发现许多地震震中局限在某些区域性断裂中。H.施蒂勒(Stille)详细地论述了欧 相似文献
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华北克拉通及邻区晚中生代伸展构造及其动力学背景的讨论 总被引:13,自引:8,他引:5
欧亚大陆东部晚中生代伸展构造十分显著,表现为大量发育的变质核杂岩、同构造岩浆岩、韧性拆离断层带等伸展成因的穹隆和地堑-半地堑盆地.通过对这些伸展构造进行系统分析、归纳和总结,将欧亚大陆东部晚中生代伸展构造发育区划分为:泛贝加尔-鄂霍次克带、华北西部带、华北东部带、华北南缘及秦岭-大别带和华南内陆带.这些伸展构造记录了大区域上的NW-SE方向伸展,构成了全球最大的陆壳伸展地区.这些伸展构造使地壳深部的岩石沿拆离断层折返至地表,从而使中下地壳结构发生了强烈的改造.除华北东部带给出了一个较为宽泛的伸展时段外,各个研究区所涉及的伸展穹隆及其相关的拆离断层所表现的伸展峰期时间均十分相近:位于130 ~ 126Ma之间.岩石圈根部的拆沉可能是这个巨型伸展构造带形成的动力学机制.这个模型为探讨华北克拉通破坏和减薄的时限、机制、模式及深部动力学背景提供直接的构造证据. 相似文献
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前言显微构造分析在研究岩浆期后热液矿床的作用,逐漸为地貭工作者所重視。作者在研究南岭某钨錫矿田构造时,在配合其他地貭方法的同时,系統地进行过显微构造分析工作。这些結果对解决我們面临的地貭問題有一定的重要意义。該矿田位于华南加里东褶皺带的浅变貭岩中,岩层走向近于南北。加里东运动后,該区一直处于隆起状态。中生代时由于燕山运动而发生了强烈的构造断裂和岩浆活动,随后,有鎢錫矿的形成。鉴于成矿与花崗岩在时間上(絕对年龄測定均属燕山早期)、空間上和地球化学等方面有密切的联系,因此,公认矿化与花崗岩有成因上的联系。矿床属高溫热液脉状矿床。 相似文献
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Agust Gudmundsson 《地学学报》1993,5(3):215-224
Studies of the oceanic fracture zones, as well as field observations of the on-land parts of a fracture zone in Iceland, show that there are numerous tension fractures, normal faults, small-scale grabens and dykes within, and trending subparallel with, the fracture zones. These structures indicate that, in addition to the shear displacement, there is considerable extension associated with the development of fracture zones and that many of them may be regarded as complex graben structures. The ridges surrounding the continents of Africa and Antarctica are examples of mid-ocean ridges that are moving away from the continental margins where they originated and therefore expanding. Here it is suggested that as the perimeter of an expanding ridge increases, the tensile stresses associated with the ridge extension may contribute to the formation of fracture zones. 相似文献
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青藏高原是地球上最高大和最雄伟的年青隆起区。对于它的形成和演化机制,一直是国内外地质和地球物理学者注意的问题之一。 近十年来,人们认为青藏高原的形成是由于相距千里之遥的印度板块向北漂移并与欧亚板块碰撞的结果。然而,根据作者对喀喇昆仑和喜马拉雅等地的野外考察及其深部地球物理资料的研究,提出青藏高原原来是一个统一的前震旦纪陆壳区,后经震旦纪以来多次的拉开和挤压碰撞而形成的新观点。这种拉开和挤压的运动方式,是深部鳗隆和慢拗的分异作用引起的。 相似文献
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Prof. Dr. Henning Illies 《International Journal of Earth Sciences》1970,59(2):528-552
A system of intracontinental grabens extends over Western Europe, the Levant and East Africa. Small crustal segments framed by elevated shoulders are sunken along parallel escarpments and disintegrated by antithetic normal faults. The shoulders are risen up as outward tilted blocks and thought to form a closed vault at the base of the crust, corresponding to the wedge block of the graben. Underneath the Rhinegraben exists, as detected by seismic refraction measurements, a pillow-shaped body of material with P-wave velocities of 7.4 to 7.9 km/sec, intercalated between crust and mantle. The taphrogenesis of all larger grabens is assumed to be induced by the formation and growth of subcrustal swells of this type. Also the specific graben volcanism is thought to be connected with the intruded laccolithic body of mantle-derived material. The tensional breakup and the faulting of the warped crustal masses was favoured by the gravity slide of the crust which was uncoupled from the substratum by the intercalated magmatic layer. Along the Red Sea Rift the crust tore completely releasing the basaltic substratum in the inner graben. The pattern of its magnetic anomalies leads to the assumption that the pillow body is recruited by simatic dike injections according to the principle of sea-floor spreading. Therefore, there is a great conformity between the intercontinental and the mid-oceanic rift systems. The supplies of mantle material along the Mid-Atlantic and the Carlsberg Rift are related to the drift of the continental frames. The mid-oceanic rift systems in their medial position to the framing continental margins correspond to the intracontinental graben swarm, equidistant from both fronts of circum-Pacific tectonics. A reciprocating action is presumed between the ascending masses along the rift zones and the suction of masses along the deep-sea trenches and geosynclines. The observed crustal movements imply an equilibrant plastic flow within the upper mantle, probably impelled by mechanical convection currents. The continental unbalance between the Pacific and the anti-Pacific hemisphere is discussed as causing mantle currents. Within this interplay between crust and mantle and between continents and ocean floors, the oceanic crust had obtained harmonical features moulded directly by the deduced mobility. The continental crust, however, is passively stressed, its rocks are affected by heterogeneous deformations from which the continents got its polygenetic multiform fabric. 相似文献