Regional‐to‐Global Tectonic and Trench‐Morphology Effects of Oceanic Plateau Subduction

Abstract Regional geodynamic modeling has shown that oceanic plateau subduction can modify the slab behavior. However, few studies have explored these interactions beyond 100 Myr in 3‐D spherical models. Using 3‐D spherical mantle convection models with self‐consistent plate‐like behavior, we investigate how the geometry and rheological properties of oceanic plateaus influence trench evolution and mantle flow across regional to global scales. Our models show that plateau width and thickness exert the strongest control on trench retreat, while buoyancy alone plays a secondary role. A mechanically strong plateau produces a transient arcuate trench morphology that gradually heals once the plateau is fully subducted, leaving only a delay in retreat. The pronounced curvature of the northern Mariana Trench suggests that the Ogasawara Plateau is mechanically strong. Although plateau subduction leaves no long‐term geological scar unless slab break‐off occurs, it substantially slows trench migration and can influence global tectonic evolution for over 200 Myr.