Lower Crustal Rheology Controls Strain Partitioning and Mode of Intracontinental Deformation
Lower Crustal Rheology Controls Strain Partitioning and Mode of Intracontinental Deformation
复制标题
下地壳流变学控制应变分配与大陆内部变形模式
DOI：
10.1029/2023tc007748
复制
发表时间：
2023-07
期刊：
影响因子：
4.2
通讯作者：
Xi Xu;A. Zuza;A. Yin;YU Peng;Zhiyong Chen;Chongjin Zhao;Baodi Wang;Hanlin Chen;Xiubin Lin;L. Wu;Xingtao Kuang;Hefeng Tian;Qihang Yin;Shufeng Yang
中科院分区：
文献类型：
--
作者：
Xi Xu;A. Zuza;A. Yin;YU Peng;Zhiyong Chen;Chongjin Zhao;Baodi Wang;Hanlin Chen;Xiubin Lin;L. Wu;Xingtao Kuang;Hefeng Tian;Qihang Yin;Shufeng Yang
控制应变分配的因素沿着板块边界和大陆内部仍然没有解决。板块会聚可以通过分布的地壳缩短或离散的地壳尺度的走滑断层作用来适应，但控制这些不同变形模式的因素仍有争议。在这里，我们通过研究亚洲中部塔里木盆地周围的活跃变形区域来解决这个问题，那里的变形被独特地划分为东部的走滑断层和西部的褶皱冲断带，以适应新生代印度-亚洲板块的会聚。本文通过对塔里木盆地及其周边地区的地质和地球物理观测资料的综合分析，阐明了塔里木盆地及其周边地区的地壳形变和成分结构特征。塔里木盆地西部以逆冲为主，与下地壳的强磁性有关，而沿着塔里木盆地东缘的走滑断层则缺乏这种磁性信号。我们认为，塔里木西部的下地壳比东部更镁铁质和更强，这影响了板内应变分配。较强的下地壳导致垂直解耦，以驱动中地壳水平滑脱并促进逆冲断层，而更均匀的地壳有利于垂直穿壳走滑断层。这些流变学差异可能源于集中在西部的二叠纪塔里木热柱的撞击。与青藏高原东部龙门山的比较揭示了非常相似的应变分配与前陆流变学的变化。我们的研究结果突出了下地壳粘度的变化如何影响板内环境中的应变分配，以及羽流过程如何对后期大陆构造过程产生强有力的控制。
The factors that control strain partitioning along plate boundaries and within continental interiors remains poorly resolved. Plate convergence may be accommodated via distributed crustal shortening or discrete crustal‐scale strike‐slip faulting, but what controls these differing modes of deformation is debated. Here we address this question by examining the actively deforming regions that surround the Tarim Basin in central Asia, where deformation is uniquely partitioned into predominately strike‐slip faults in the east and distributed fold‐thrust belts in the west to accommodate Cenozoic India‐Asia plate convergence. We present integrated geological and geophysical observations to elucidate patterns in crustal deformation and compositional structure in and around the Tarim Basin. The thrust‐dominated western Tarim Basin correlates with a strongly‐magnetic lower crust, whereas strike‐slip faulting along the eastern margins of the Tarim Basin lack such magnetic signals. We suggest that the lower crust of the western Tarim is more mafic and stronger than in the east, which impacts intra‐plate strain partitioning. A stronger lower crust results in vertical decoupling to drive mid‐crust horizontal detachments and facilitate thrust faulting, whereas a more homogenized crust favored vertical transcrustal strike‐slip faulting. These rheological differences likely originated from the impingement of the Permian Tarim plume focused in the west. A comparison with the Longmen Shan of eastern Tibetan Plateau reveals remarkably similar strain partitioning that correlates with variations in foreland rheology. Our results highlight how variations in lower‐crust viscosity impact strain partitioning in an intra‐plate setting and how plume processes exert a strong control on later continental tectonic processes.