中国东部中新生代盆—山系及有关地质现象的成因机制

    ON THE FORMATION MECHANISM OF THE MESO-CENOZOIC BASIN-RANGE SYSTEM AND ITS RELATED GEOLOGICAL PHENOMENA IN EASTERN CHINA

    • 摘要: 中国东部中新生代盆—山系及有关地质现象,受水平挤压力和重力共同作用而呈正断层产出的上地壳平面X型断裂—压剪性正断层的控制,分别形成于晚保罗—早白垩世库拉板块北北西向挤压和晚自垩世以来印度板块北东向挤压时期。其断层上盘在重力作用下的受力状态和变形情况,类似于以中地壳塑性层为弹性基础、以断层面为自由端的悬臂梁,从而在该梁的弯矩和剪切力作用下,形成箕状断陷盆地。盆地基底在大幅度沉降过程中,把下伏中地壳塑性物质大量压向下盘,促使该盘上升为断隆山,使阴山、燕山、秦岭和太行山等山脉与断陷盆地毗邻。富含有用元素的中地壳高温塑性物质的上升,还产生了变质核杂岩、岩浆活动、成矿作用、高热流和地质灾害。

       

      Abstract: The Meso-Cenozoic basin-range system and its related geological phenomena in easternChina originated at the stage of the NNW compression of the Kola plate during the LateJurassic-Early Cretaceous and at the stage of the NE compression of the indian plate sincethe Late Cretaceous. They are controlled by the plane X-type fracture of the upper crustcompresso-shear normal fault-which was produced by the combined action of the horizontalcompressive force and gravity. The loading state and deformation of the hanging wall of thefault under gravity are similar to a centilever beam with the plastic layer in the middle crustas the elastic foundation and with the fault surface as the free end ithus,under the action ofthe curved moment and shear force of the beam,a listric down-faulted basin was formed. Alot of plastic materials in the middle crust were pressed to the footwall and the footwall uplifted as a fault-uplift mountain during the large-amplitude subsidence of the basin basement,so that the Yinshan,Yanshan,Qinling and Taihang mountains are juxtaposed with the downfaulted basin and both of them were formed at almost the same time and have a similar scale.The rise of high-temperature plastic materials rich in useful elements in the middle crust alsoled to production of the metamorphosed nuclear complex, magmatism, mineralization, highheat flow and geological hazards.

       

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