Plate Tectonics

Abstract

Plate tectonics refers to the global system of coupled boundaries along mid-ocean ridges, subduction zones and transform faults on Earth. It operates through continental drift, seafloor spreading and lithospheric subduction, shaping the Earth surface throughout geological time. Earth is the only rocky planet in the solar system with plate tectonics. The system of lithospheric plates in constant motion forms a link between the deep and surface Earth reservoirs. Therefore, plate tectonics is recognizable in the rock record produced by such processes as rifting, collision and subduction. It comprises three elements: rigid lithosphere plates; persistent plate margins; and horizontal movement relative to other plates. Subduction has played a key role in the operation of plate tectonics. On the one side, the lithospheric descending is associated with plate convergence, making the extensional space at backarc sites through slab rollback for regional upwelling of the asthenosphere and thus for active rifting. On the other side, it is coupled with plate divergence along mid-ocean ridges, leading to passive rifting for seafloor spreading. Rigid lithosphere may have ductile margins during plate convergence, leading to the operation of plate tectonics in different styles. Modern plate tectonics is characterized by the predominance of rigid plate margins for cold subduction, which has prevailed since the Neoproterozoic. In contrast, ancient plate tectonics is indicated by the predominance of ductile plate margins for warm subduction, which had prevailed since the Archean. In either case, the operation of plate tectonics is responsible for the creation and maintenance of a global network of mobile belts along plate boundaries.