为何塔里木盆地独立于青藏高原整体变形之外而柴达木盆地却并入其中?  

Why Qaidam Basin is amalgamated into Tibetan Plateau but Tarim Basin is not?

作　　者：裴旭 皇甫鹏鹏 李忠海 石耀霖 PEI Xu;HUANGFU PengPeng;LI ZhongHai;SHI YaoLin(Key Laboratory of Computational Geodynamics,College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大学地球与行星科学学院,计算地球动力学重点实验室,北京100049

出　　处：《地球物理学报》2022年第11期4259-4272,共14页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(91855208,42074107,42030307,41704091);第二次青藏高原综合科学考察研究专题“典型地区岩石圈组成,演化与深部过程”(2019QZKK0702);中央高校基本科研业务费专项资金联合资助.

摘　　要：青藏高原北缘盆地与高原之间的协调变形是青藏高原壳幔演化变形的核心问题之一.塔里木盆地和柴达木盆地虽然都位于青藏高原北缘,但最终表现出不同结果;其中,柴达木盆地并入青藏高原并随之整体变形,而塔里木盆地仍然保持其几何和力学完整性,从而独立于青藏高原的整体变形之外.两盆地差异性演化的物理机制研究目前仍较为薄弱.本文基于塔里木盆地与柴达木盆地的共性与差异性,以青藏高原一级构造演化为约束,建立二维热-动力学数值模型,通过系统的数值模拟实验,研究坚硬块体并入高原的壳幔变形过程及其控制因素.实验结果表明,坚硬块体是否并入高原并成为其一部分主要受控于坚硬块体的长度和地壳强度.具体地,坚硬块体越长,地壳强度越大,越不容易并入高原内部.因而,相比于柴达木盆地,面积更大更坚硬的塔里木盆地更难并入青藏高原.The deformation evolution of the basins in northern Tibetan Plateau is crucial for better understanding the dynamics of Tibetan Plateau,especially the growth of the plateau.Despite both located in the northern Tibetan Plateau,the Tarim and Qaidam basins experienced distinct deformation modes.Specifically,the Qaidam Basin has been completely integrated into the plateau,whereas the Tarim Basin behaves as an independent unit resistant to the Tibetan deformation.The physical mechanism for the different deformation modes of the two basins is poorly understood.Focusing on this issue,we have conducted a series of two-dimensional thermo-mechanical numerical modeling based on the first-order tectonic settings of the Tibetan Plateau.The model results indicate that the controlling factors affecting crustal-scale deformation propagation are the length and crustal strength of the block.Specifically,a longer or a plastically stronger block inhibits the deformation migration towards the basin interior.Therefore,in contrast to the Qaidam Basin,the Tarim Basin can maintain its geometric and mechanical integrity.

关 键 词：柴达木盆地 塔里木盆地 青藏高原 岩石圈变形 数值模拟 

分 类 号：P313[天文地球—固体地球物理学]