plattteorin

Plattteorin, or plate tectonics theory, is the scientific framework that explains the large-scale movement of the Earth's lithosphere, which is divided into a number of rigid plates that ride atop the partially molten asthenosphere. The theory unifies continental drift, seafloor spreading, and the distribution of earthquakes and volcanoes.

These plates include oceanic crust, continental crust, and, in some models, microplates. They interact at plate boundaries classified as divergent (moving apart), convergent (coming together often with subduction or collision), and transform (sliding past each other). Interactions produce mid-ocean ridges, deep-sea trenches, mountain belts, earthquakes, and volcanism.

Movement is driven by forces such as mantle convection, slab pull, and ridge push. The descent of cold lithosphere at subduction zones and the gravitational sliding of plates away from spreading centers contribute to observable plate motions, typically a few centimeters per year.

Evidence for plate tectonics includes the fit of continental margins, patterns of paleomagnetism showing historical reversals, stripes of magnetic anomaly on the seafloor, age distribution of oceanic crust, and the global distribution of earthquakes and volcanoes concentrated along plate boundaries and hotspot tracks such as the Hawaiian-Emperor seamount chain. Modern measurements rely on GPS and space geodesy.

Historically, Wegener's theory of continental drift (early 20th century) argued that continents moved but lacked a plausible mechanism. In the 1960s, seafloor spreading and magnetic evidence, advanced by Vine and Matthews and by Isacks, Isacks, and Oliver, along with J. Tuzo Wilson's concept of transforming boundaries, led to the broad acceptance of plate tectonics as a unifying theory of Earth's geodynamics.

Plattteorin explains the assembly and breakup of supercontinents, mountain building, earthquakes, and volcanic activity, and it remains central to understanding Earth's past, present, and future geologic evolution.