秦岭的由来

发布时间：2018-11-18 07:05

【摘要】：秦岭山脉是在新生代发生强烈隆升而形成的,但它在古生代-中生代却经历了一个漫长的造山带演化过程.秦岭造山带的发展涉及到大洋板块俯冲、弧后盆地扩张、不同陆块/地体分离与拼合以及造山期后强烈陆内变形.晚中生代秦岭造山带大规模走滑变形、地体侧向挤出以及陆壳俯冲等地质过程最终奠定了秦岭造山带现今的平面几何形态和内部地质结构.秦岭造山带演化所形成的挤压构造地貌在晚白垩世-古新世阶段被完全夷平.秦岭山脉新生代的隆升与地壳伸展作用相关,而非挤压构造的结果.秦岭山脉隆升与北侧渭河盆地沉降同时发生,两者构成了一个完整的伸展构造环境下的山-盆体系.秦岭山脉的隆升速率在晚始新世-渐新世中期相对缓慢,在渐新世晚期-中新世早期基本停止.中新世中期秦岭山脉开始重新隆升,并且在晚中新世-第四纪隆升速率明显增大.秦岭山脉的隆升主要受其北缘断层的控制.当秦岭北缘断裂为正断层时,它不仅导致上盘渭河盆地强烈断陷,而且造成下盘的秦岭山脉发生翘倾抬升.当秦岭北缘断裂为压扭性走滑断层时,它所引发的挤压作用则使渭河盆地发生抬升和剥蚀,秦岭山脉也停止了翘倾抬升.秦岭北缘断裂在1 0百万年左右演化为一个侧向连续的大型正断层,从而导致秦岭山脉自晚中新世以来发生强烈快速隆升.
[Abstract]:The Qinling Mountains were formed during the Cenozoic, but it underwent a long orogenic evolution in the Paleozoic and Mesozoic. The development of Qinling orogenic belt involves the subduction of oceanic plate, the extension of back-arc basin, the separation and assembly of different continental blocks / terraces and the strong intra-continental deformation after orogeny. The late Mesozoic Qinling orogenic belt was characterized by large-scale strike-slip deformation, lateral extrusion of the body and subduction of the continental crust, which finally established the present plane geometry and internal geological structure of the Qinling orogenic belt. The compressional tectonic landforms formed by the evolution of the Qinling orogenic belt were completely flattened in the late Cretaceous-Paleocene stage. The Cenozoic uplift of the Qinling Mountains is related to crustal extension, not the result of compressional tectonics. The uplift of Qinling mountain range and the subsidence of the Weihe basin on the north side occur simultaneously, which constitute a complete mountain basin system under extensional tectonic environment. The uplift rate of the Qinling Mountains was relatively slow from the late Eocene to the middle Oligocene, and stopped in the late Oligocene to the early Miocene. The Qinling Mountains began to rise again in the middle Miocene and the rate of uplift increased obviously in the late Miocene and Quaternary. The uplift of the Qinling Mountains is mainly controlled by faults in its northern margin. When the fault in the northern margin of Qinling Mountains is a normal fault, it not only leads to a strong fault depression in the Weihe basin of Shangpan, but also results in the uplift of the Qinling Mountains in the lower reaches. When the fault in the northern margin of Qinling Mountains is a compression-torsional strike-slip fault, the compression caused by the fault causes uplift and denudation of the Weihe basin, and the uplift of the Qinling Mountains stops. The faults in the northern margin of the Qinling Mountains have evolved into a lateral continuous large normal fault for about 10 million years, resulting in a strong and rapid uplift of the Qinling Mountains since the late Miocene.
【作者单位】：岩石圈演化国家重点实验室中国科学院地质与地球物理研究所;中国科学院大学地球科学学院;
【基金】：国家自然科学基金项目(批准号:40830314,91114204)资助
【分类号】：P542

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