• ISSN 2097-1893
    • CN 10-1855/P

    早期地球构造模式演化的动力学研究

    Geodynamics of early Earth tectonic regimes

    • 摘要: 地球作为太阳系中唯一拥有活跃板块构造的行星,其早期构造体制与演化过程是地球动力学研究的核心问题. 板块构造的启动机制、起始时间及演化历程直接关乎地球宜居性的形成与持续,然而,目前对此仍存在较大争议. 本文基于地球动力学理论与前人的数值模拟研究,系统总结归纳了早期地球可能存在的六种构造模式:停滞盖、移动盖、深成软盖、热管模式、岩石圈滴落式俯冲及洋脊模式,分析了各模式的动力学特征、控制参数与地质证据. 本文深入探讨了板块构造启动的四种主要机制:地幔热柱诱发俯冲、撞击驱动俯冲、大陆重力扩展启动俯冲以及热裂解. 关于全球板块构造的启动时间,现有观点分歧显著,时间跨度从冥古宙延伸至新元古代,反映了地质记录的不完整性与多解性. 俯冲的启动是板块构造建立的关键,但其初始条件与持续机制仍需进一步通过数值模拟与地质记录综合约束. 早期地球构造演化受地幔温度、岩石圈流变性质及岩浆作用等多因素调控,从岩浆洋冷却后的停滞盖状态,经多种过渡模式,逐步发展为现代板块构造体系. 总体而言,早期地球的构造演化是一个复杂的非线性动力学过程,对其展开研究需综合地球动力学数值模拟、多学科地质观测以及行星比较分析. 这种多维度分析有助于逐步揭示板块构造体制的起源、演变过程及其对地球系统演化的深远影响.

       

      Abstract: Earth is unique in our solar system for having active plate tectonics, and understanding its tectonic regimes and the early evolutionary processes are pivotal to geodynamic research. The initiation mechanisms, onset time and evolution of plate tectonics have a profound impact on the formation and maintenance of Earth's habitability; however, significant controversy remains regarding these topics. Based on geodynamic theories and numerical simulations, we systematically elucidate six potential tectonic modes of the early Earth: stagnant lid, mobile lid, plutonic-squishy lid, heat-pipe mode, drip-like subduction, and ridge-only mode, and further analyzes the dynamic characteristics, controlling factors, and geological evidence associated with each mode. We also describe four mechanisms for subduction initiation: plume-induced subduction, impact-driven subduction, subduction induced by spreading continents and plate-breaking. While subduction initiation is critical to establishing plate tectonics, its initial conditions and sustaining mechanisms require further constraints through integrated numerical modeling and geological records. Current perspectives on the onset time of global plate tectonics vary widely, with evidence suggesting it could have begun as early as the Hadean, around 4 billion years ago, to the Neoproterozoic era. This discrepancy reflects the incomplete and ambiguous nature of the geological record. The tectonic evolution of the early Earth was governed by multiple factors, encompassing mantle temperature, rheology, and magmatism. Following the cooling of the magma ocean, the Earth likely transitioned from a stagnant-lid state through various transitional modes, gradually evolving into the modern plate tectonic system. To summarize, the tectonic evolution of the early Earth represents a complex, non-linear dynamic process. Integrating geodynamic numerical simulations, multidisciplinary geological observations, and comparative planetary analysis is essential to unraveling the origin and evolution of tectonic regimes and their profound impact on the evolution of the Earth system.

       

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