Five tectonic modes of mantle convection are obtained and analyzed with three-dimensional numerical models in a spherical shell domain. The five tectonic convective modes are non-plate mobile-lid, plate-like mobile-lid, episodic plate-like mobile-lid, episodic stagnant-lid, and stagnant-lid convective modes, respectively. The typical characteristics of these five tectonic modes and their numerical classification criteria based on plateness, mobility, and their standard deviations are presented and discussed. The results show that the yield stress of the lithosphere has profound effects on the tectonic convective modes. With the gradual increase of yield stress, the tectonic mode of mantle convection changes from one to another sequentially through the aforementioned five modes. Additionally, as the Rayleigh number increases, the range of yield stress for the platelike mobile-lid convective mode decreases, and the dimensionless transition stress between different tectonic modes increases. Specifically, the dimensional transition stress between the non-plate mobile-lid convective mode and plate-like mobile-lid convective mode increases with the increase of Rayleigh number, but decreases between other tectonic modes. Furthermore, we find that the transition stress between different tectonic modes is inversely proportional to the internal heating rate, with the transition stress decreasing as the internal heating rate increases. The fitting analysis of the transition stress between tectonic modes shows that Earth’s current plate tectonics correspond to a lithospheric yield stress of 150–250 MPa, which aligns with the strength of serpentinized mantle rock determined by experimental petrography. If the Archean mantle was 300°C warmer than it is today, then the Earth was in an episodic stagnant-lid convective mode. The tectonic evolution of the Earth’s surface is closely related to the lithospheric strength and the process of thermal evolution. If the lithospheric strength was only 150 MPa, plate tectonics in the early mantle rapid cooling model would have begun before 3.8 Ga, and plate tectonics in the late mantle rapid cooling model would have begun at approximately 1.5 Ga. However, at a lithospheric strength of 200 MPa, plate tectonics in the late mantle rapid cooling model would have begun later than 0.95 Ga, and plate tectonics in the early mantle rapid cooling model would have begun at approximately 2 Ga. The early Earth was in the episodic stagnant-lid convective mode, which means that subduction might still have occurred at that time. The presence of the episodic plate-like mobile-lid convective mode in Earth’s later history indicates that there might also have been intermittent surface stagnation during plate tectonics, which may provide an explanation for the quiet period of tectonic activity at approximately 1.0 Ga on Earth. This indicates that tectonic inactivity during a geological period is not an indicator that plate tectonics did not begin.
