Microplate Tectonics Through Earth History and Across Solid Multispheres

ABSTRACT The evolution of tectonic microplates throughout Earth's history as well as the transitions between microplates across different solid spheres offers a novel approach to expanding the traditional plate tectonics theory. The microplate tectonics theory is an Earth science framework that focuses on the entire geological history of the solid Earth and all of its spheres. Tectonic microplates evolve from mantle microblocks via oceanic microblocks and progressively develop into continental microblocks. Concurrently, Earth's tectonic system shifted from a non‐plate (pre‐plate) tectonic regime to the modern plate tectonic regime. Based on advances in solid Earth science over the past decade, this paper briefly reviews the evolution of the primordial Earth's tectonic system since its formation 4.54 Ga ago. It traces the process from accretion tectonics of the planetesimal accumulation stage, and the heat‐pipe and stagnant lid tectonics of the cooling stage of the magma ocean, to the impact tectonics of the prolonged Late Heavy Bombardment stage. This is followed by the sagduction tectonics of the squishy lid stage, mantle plume tectonics and hot subduction tectonics. Finally, it transitions to modern asymmetric plate tectonics. This study clarifies the temporal sequence of microplate evolution, changes in rock composition, geometric shapes and sizes, the transition of operational mechanisms and the evolution of tectonic systems under various regimes. It points to some new approaches for addressing three major challenges of traditional plate tectonics theory.