张星宇,杜劲松,陈超,梁青

• 1:中国地质大学(武汉)地球物理与空间信息学院地球内部多尺度成像湖北省重点实验室
• 2:中国地质大学(武汉)地质过程与矿产资源国家重点实验室

摘要(Abstract)：

自新生代印度板块的块持续碰撞与俯冲作用下，青藏高原经历了快速隆升与复杂的岩石圈改造过程，但高原现今的垂向动力学机制和地壳形变特征仍然存在争议。基于非均一有效弹性厚度的挠曲模型，利用地形和地球重力场模型数据，计算了青藏高原及邻区的挠曲均衡重力异常。结果显示，青藏高原的均衡重力异常在-120～90 mGal之间，高原中部为明显的正异常特征，边缘为显著的均衡负异常。极小值出现在青藏高原西北部及其相邻的帕米尔高原，极大值则出现在与之紧邻的喜马拉雅块体西北部。此外，在青藏高原北面和东面，塔里木盆地和四川盆地显示出大片的均衡正异常。这些特征说明青藏高原及邻区地壳现今处于非均衡的状态，在板块碰撞挤压作用下，老的块体地壳整体发生抬升，导致了均衡正异常特征；而年轻的造山区域，地壳形变主要表现为地表抬升与下地壳强烈增厚，形成了均衡负异常。在高原中部和北部，均衡调整方向与地壳垂向运动趋势相一致；但在高原南面(喜马拉雅块体)和东面(四川盆地),均衡调整方向与地表形变观测结果相反。这说明印度板块碰撞与俯冲仍然控制着青藏高原南部、东部及其相邻块体的地壳形变过程，然而在更北的区域，地壳正通过均衡调整恢复均衡状态。

关键词(KeyWords)： 青藏高原;弹性板;挠曲均衡;均衡重力异常;地质意义

Abstract:

Keywords:

基金项目(Foundation): 国家自然科学基金项目(41774091;42174090);; 地质过程与矿产资源国家重点实验室科技部专项(MSFGPMR2022-4)

作者(Author): 张星宇,杜劲松,陈超,梁青

DOI: 10.19509/j.cnki.dzkq.tb20220621

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