Mantle cooling and continental growth control the initiation and cessation of plate tectonics

Understanding the initiation of plate tectonics on Earth is crucial for unraveling our planet’s geological history and understanding its unique tectonic regime. The roles of mantle cooling and continental crust growth in triggering plate tectonics remain controversial, in part due to the paucity of quantifiable evidence. We employed two-dimensional numerical models to investigate the process, timing, and underlying mechanisms of tectonic regime transitions throughout Earth history. Our simulations reveal two pivotal transitions, i.e., initiation and cessation of plate tectonics, that divide the evolution of the global tectonic regime into three stages. These transitions reflect thickening and strengthening of lithosphere with long-term cooling of Earth’s mantle. In the model, initially, Earth’s tectonic regime is characterized by vertical tectonics, with upwelling of hot mantle and melts along with dripping and delamination. The lithosphere in this stage is not strong and dense enough for subduction; thus, plate tectonics is hindered. Further on, it transitions into a second stage where subduction is favored, marking the onset and sustained operation of plate tectonics. Finally, in the third stage, thickening and strengthening of the lithosphere make subduction increasingly difficult, which terminates the plate tectonics. We use numerical modeling to demonstrate that lithospheric density and strength, as well as contrasts between oceanic and continental lithospheres, are governed by mantle cooling and influenced by continental growth. In turn, these properties orchestrate the interplay between plate rigidity and localized weakening under horizontal motion, which drives global subduction initiation and these tectonic transitions. Integration of our models with the geological record suggests that a transition to plate tectonics became possible by ca. 2.4 Ga to 1.8 Ga, whereas the eventual cessation of plate tectonics is likely to occur ∼2.1−2.3 b.y. into the future. Progressive strengthening of lithosphere with mantle cooling is generally applicable to planetary evolution and may provide valuable insights for the tectonic evolution of other active silicate planets, including Mars and Venus.