The inception of plate tectonics on Earth and its subsequent evolution are discussed on the basis of theoretical considerations and observational constraints. The likelihood of plate tectonics in the past depends on what mechanism is responsible for the relatively constant surface heat flux that is indicated by the likely thermal history of Earth. The continuous operation of plate tectonics thr...

We present an overview of the relation between mantle dynamics and plate tectonics, adopting the perspective that the plates are the surface manifestation, i.e., the top thermal boundary layer, of mantle convection. We review how simple convection pertains to plate formation, regarding the aspect ratio of convection cells; the forces that drive convection; and how internal heating and temperatu...

Plate tectonics is a kinematic description of Earth that treats the outer shell of its mantle as a number of plates or rigid spherical caps that move with respect to each other (see the “Plate tectonics” sidebar). The mantle is the outer, solid 3,000-km-thick shell that overlies Earth’s fluid outer core. An enormous amount of geological and geophysical data has gone into determining the motion ...

[1] The net influx of water into the deep mantle by plate tectonics has been poorly constrained because it is difficult to quantify how efficiently subducting slabs are devolatilized on a global scale. The significance of deep water cycle in the Earth history is similarly ambiguous because it depends critically on when plate tectonics started and how it evolved through time. Here I show that, u...

Today, plate tectonics is the dominant tectonic style on Earth, but in a hotter Earth tectonics may have looked different due to the presence of more melting and associated compositional buoyancy as well as the presence of a weaker mantle and lithosphere. Here we review the geodynamic constraints on plate tectonics and proposed alternatives throughout Earth’s history. Observations suggest a 100...

The realization that Earth may have lost heat more slowly in the past than at present has motivated the search for mechanisms to reduce the efficiency of plate tectonics in the past. Several mechanisms have been proposed, such as the resistance to subduction of thick plates (1) produced by deeper melting at higher mantle temperatures (2). We (3) proposed an alternative mechanism, namely subduct...

The Earth stands out in the solar system as the only planet with plate tectonics. This peculiarity is due not only to strong internal heating but also a lithosphere rheology characterized by brittle failure and localization, as a comparison with Venus clearly show. Localization in the ductile regime are manifested on Earth by ductile shear zones, which have proven difficult to explain theoretic...