近日，中国科学院地质与地球物理研究所徐亚团队，在研究青藏高原及其邻区岩石圈应力状态特征及地质意义中取得新突破。相关论文于2024年5月21日发表在《中国科学：地球科学》杂志上。

据介绍，青藏高原及邻近地区现今岩石圈应力状态受岩石圈本身和下伏地幔共同控制。即由岩石圈内部密度分布变化引起的重力势能差（GPE），和地幔对流引起的岩石圈底部拖拽力对应力的影响。岩石圈应力状态的研究对进一步认识青藏高原演化的动力背景和机制具有重要意义。

研究人员利用Crust1.0地壳密度模型与S40RTS地幔密度横波速度变化模型相结合用于计算GPE。EGM2008重力场模型用于计算岩石圈底部地幔对流拖拽力。通过求解薄板近似下的力平衡，研究人员得到了两个源的岩石圈和接合应力场。研究人员全面分析了高原内部应力状态的特征，根据GPE应力场、地幔拖拽力应力场、两种应力场的相对大小以及两种应力场与地表变形的相关性，划分了6个区域。

塔里木盆地及其他稳定块体的岩石圈应力场主要受GPE差的控制。印度板块与青藏高原碰撞带的岩石圈应力场主要受深部地幔拖曳力控制。青藏高原内部岩石圈应力场受GPE和地幔拖拽力的双重控制。青藏高原东南缘岩石圈应力场与地表变形相关性较差。假设存在有效黏度较低的下地壳流动导致壳幔解耦，地幔拖拽力对浅部地壳的影响较弱，导致岩石圈平均应力场与地表变形不一致。

附：英文原文

Title: Characteristics and geological significance of the stress state of the lithosphere in the Qinghai-Tibetan Plateau and its neighboring areas

Author: Qianwen ZHANG, Ya XU, Wei CHU, Shupeng LU

Issue&Volume: 2024/05/21

Abstract: The present-day lithospheric stress state of the Qinghai-Tibetan Plateau and neighboring areas is controlled by both the lithosphere itself and the underlying mantle. In other words, the stress is affected by the gravitational potential energy (GPE) difference caused by the change in the density distribution within the lithosphere and the drag force on the base of the lithosphere caused by mantle convection. The study of the lithospheric stress state plays an important role in further understanding the dynamic background and mechanism for the evolution of the Qinghai-Tibetan Plateau. In this study, the Crust1.0 crustal density model combined with the S40RTS mantle shear wave velocity variation model was used to calculate the GPE. The EGM2008 gravity field model was used to calculate the drag force from mantle convection at the base of the lithosphere. The lithospheric and joint stress fields of the two sources were obtained by solving the force balance under the thin sheet approximation. This way, we could comprehensively analyze the characteristics of the stress state within the Plateau. Six regions were classified according to the GPE stress field, mantle drag force stress field, the relative magnitude of the two stress fields, and correlation between the two stress fields and surface deformation. The lithospheric stress fields of the Tarim Basin and other stable blocks are mainly controlled by the GPE difference. The lithospheric stress field in the collision zone between the Indian Plate and the Qinghai-Tibetan Plateau is predominantly controlled by the deep mantle drag force. The lithospheric stress field in the interior of the Plateau is controlled by both GPE and mantle drag. The correlation between the lithospheric stress field and surface deformation at the southeast margin of the Qinghai-Tibetan Plateau is poor. It is hypothesized that the presence of lower crustal flow with lower effective viscosity leads to crust-mantle decoupling, and the mantle drag force has a weaker influence on the shallow crust, resulting in the inconsistency between the average lithospheric stress field and surface deformation.

DOI: 10.1007/s11430-023-1288-1

Source: https://www.sciengine.com/10.1007/s11430-023-1288-1