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青藏高原东北部是探索青藏高原地球动力学的重点地区之一.自20世纪60年代以来实施的一系列深部地球物理探测和相关研究获得了该地区地壳上地幔结构的基本特征.深部地球物理探测揭示高原的地壳增厚,且具有低P波速度、低电阻率和高热流值的特点;体波走时层析成像、面波频散和远震体波接收函数反演共同显示中下地壳的低剪切波速度.回顾青藏高原东北部已有的深部地球物理研究成果,梳理出当前存在一些与地球动力学相关的问题.它们是:(1)中上地壳的低速-高导层;(2)高原地壳的增厚方式;(3)地壳和地幔各向异性;(4)下地壳通道流;(5)向南俯冲的欧亚大陆岩石圈.这些问题尚未达成一致的认识.不同的深部构造模型和观点使得对例如“下地壳通道流”和“俯冲的欧亚大陆岩石圈”有关议题争论持续不断.未能达成共识的重要原因之一可能是现有台网的数据成像分辨率和精度仍不足以识别在地壳和上地幔深处的细节.在国家和区域地震台网的基础上,正在实施的大规模流动地震台阵观测,以及重点地区开展高分辨的深部地球物理探测,将较大幅度地改善目标模型的分辨率和可靠性.这是增进青藏高原东北部深部结构和地球动力学知识的有效途径.
The northeastern Qinghai-Tibet Plateau is one of the key areas to explore the geodynamics of the Qinghai-Tibet Plateau. A series of deep geophysical exploration and related studies since the 1960s have obtained the basic features of the crust and upper mantle structure in the region. Revealing that the plateaus are thickened and have the characteristics of low P-wave velocity, low resistivity and high heat flux. The time-history tomography, surface wave dispersion and teleseismic body-wave receiver function inversion show that the middle-lower crust Low shear wave velocity.Researching the existing deep geophysical research results in the northeastern Qinghai-Tibet Plateau, it is concluded that there are some problems related to geodynamics at present: (1) the middle and upper crust at low velocity and high conductance; ( 2) the thickening of the plateau crust; (3) the crust and mantle anisotropy; (4) the lower crust channel flow; (5) the subduction of the Eurasian continental lithosphere. These issues have not yet reached a consensus. Deep tectonic models and perspectives continue the controversy over issues such as “Lower Crustal Channel Flow” and “Subducted Eurasian Lithosphere.” One of the major reasons for the lack of consensus may be the Data into Resolution and accuracy are still not enough to discern details in the depths of the crust and the upper mantle. Based on national and regional seismic networks, large-scale mobile seismic array in-situ observations and high-resolution deep geophysical Detection will greatly improve the resolution and reliability of the target model.This is an effective way to enhance the deep structure and geodynamics knowledge of northeastern Qinghai-Tibet Plateau.