【摘要】 尽管大陆只占地球表面的三分之一,但是人类生活在大陆上,大部分资源也来自于大陆,因此大陆构造研究有特别的意义,我国的地质前辈们为此做出了重要的贡献。然而,陆壳具有高度的非均质性,因此大陆构造要比大洋构造复杂的多,认识其演化规律极其困难,但是人类正在通过不同的途径朝这个目标前进。地块的侧向挤出是大陆构造的主要形式。尽管大规模的地块侧向挤出是否发生在青藏高原主体存在很大的争议,但是有证据显示地块的侧向挤出广泛地发生在青藏高原周边以及我国其它的一些造山带内,呈现出不同的规模、位移量和变形特征。位于滇西三江断裂带内的兰坪—思茅盆地在印度和华南第三纪的压扭性相互作用下向南挤出;沿喜马拉雅西构造结发生的地块侧向挤出形成于早第三纪印度与欧亚大陆之间的南北向碰撞,最新的挤出地体是塔里木盆地;雪峰地块向南的侧向挤出受控于华南地区北西—南东向区域性扭性构造作用;沿扬子地块北缘发生的地块侧向挤出形成于扬子地块与秦岭造山带中生代晚期的南北向挤压,造成四川盆地发生向西的侧向挤出;沿秦岭—大别山发生的地块侧向挤出发生在中生代,经历了超高压变质作用的下地壳随扬子地块的挤入向东运动,最后在桐柏—大别山隆升到地表,而中上地壳包括留风关复理石沉积和碧口地块向西挤出。桐柏—大别山和青藏高原均形成于大陆的碰撞,地壳都曾发生过大规模的增厚。因此,有理由相信青藏高原的下地壳和桐柏—大别山的下地壳结构和构造是一样的,要研究两者物质组成和赋存状态以及运动和变形特征可以互相参考和借鉴。例如:5·12汶川大地震的发生引发了对高原下地壳流变的关注和争论。上述桐柏—大别山中生代下地壳的侧向挤出就是通道流,由此证明青藏高原下地壳通道流是存在的;而青藏高原下地壳和桐柏—大别山一样,一定是由壳内花岗岩、活化的前寒武结晶基底、变质核杂岩以及混入的上地幔物质组成。更多还原

【Abstract】 Despite the fact that whether the large-scale crustal extrusion occurs within the Tibetan Plateau remains dispute,there exist many evidences indicating that the curstal extrusion widely occurred within the orogenic belts within the Tibetan Plateau and other orogenic belts in China with different age, style and magnitude. The curstal extrusion along the Qinling-Dabie Shan belt occurred in Mesozoic time, resulted from the north-south convergence between the North and South China, by which the lower crust that experienced ultra-high pressure metamorphism were extruded eastward and uplifted to the surface in the Tongbai-Dabie area, whereas the upper crust including the Liufengguan flysch in Triassic age and the Bikou block in Proterozoic age were extruded westward. The Lanpin-Simao Basin within the Three River fault belt was extruded to the south by the oblique convergence between the India and the South China in middle Tertiary time,separated from the Cangdu Basin to the north,leaving a space shortened in east and west direction. The curstal extrusion occu.rred along the western syntaxis of the Himalayas attributed to the northward indentation of the rigid India plate is taken up by the leftlateral movement on the Altyn Tagh fault on the north and by the right-lateral movement on the Karakunlun fault on the south. The main part of the Xuefeng block within the South China was experienced southwestward extrusion under the regional northwest-southeast compression. The Triassic flysch within the West Qinling fold belt was extruded southeastward extrusion by northsouth convergence between the Chaidum Basin and the Qilian Shan belt. Under the N-S compression between the Yangtze block and the Qinling belt along the Huangling and other domes,the Sichuan Basin was extruded to the west along a set of conjugation fault system, which led the proto-Sichuan Basin to be dismembered.更多还原