| 基于力矩平衡的板块驱动力研究 |
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| 作者姓名： | 俞霄 王世民 |
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| 作者单位： | 中国科学院大学地球与行星科学学院, 中国科学院计算地球动力学重点实验室, 北京 100049 |
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| 基金项目： | 国家自然科学基金(41374090,41674086)资助 |
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| 摘 要： | 基于刚体稳定运动的力矩平衡原理研究现今岩石圈板块运动的驱动力。提出通过计算力矩与板块角动量间夹角来识别板块驱动力的方法,并定量分析在板块底部黏性剪切阻力的约束下刚性板块运动的稳定性。采用最新的岩石圈结构模型和板块绝对运动模型计算各板块的转动惯量和角动量,进而基于简单的物理模型计算得到各板块受到的边界力矩及板底剪切力矩。结果表明:与洋脊力矩和板底力矩平衡的剩余力矩可由俯冲板片、碰撞带、裂谷带产生的力矩解释;洋脊与俯冲板片力是板块运动的主要驱动力;板块碰撞是欧亚板块运动的重要驱动力。
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| 关 键 词： | 板块构造 驱动力 力矩平衡 板底剪切 |
| 收稿时间： | 2020-04-28 |
| 修稿时间： | 2020-06-02 |
A study on the plate driving forces based on torque balance |
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| Authors: | YU Xiao WANG Shimin |
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| Institution: | Key Laboratory of Computational Geodynamics of CAS, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Plate dynamics is an important topic in geodynamics research. In this paper, the driving forces for current lithospheric plates are studied based on the principle of torque balance for stable moving rigid bodies. A method for identifying plate driving forces by calculating the angle between the torque and the plate angular momentum is proposed, and the stability of rigid plates is quantitatively analyzed under the constraint of the viscous resistant shear forces acting on the bottom of the plates. Furthermore, the moments of inertia as well as the angular momentum are computed for each plate in terms of the latest lithospheric structure model and absolute plate motion model, and the boundary and basal torques are obtained for the plates based on simple physical models. The results show that the residual torque that balances the ridge and the basal torques may be explained by those originated from the subduction slabs, collision zones, and rift zones, and that the ridge and slab forces are the main driving forces for plate motions, while the inter-plate collision are important driving forces for the Eurasian plate. |
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| Keywords: | plate tectonics driving forces torque balance basal shear |
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