Plate tectonics

Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός "pertaining to building") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted plate-tectonic theory after seafloor spreading was validated in the late 1950s and early 1960s.

The lithosphere, which is the rigid outermost shell of a planet (the crust and upper mantle), is broken up into tectonic plates. The Earth's lithosphere is composed of seven or eight major plates (depending on how they are defined) and many minor plates. Where the plates meet, their relative motion determines the type of boundary: convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically ranges from zero to 100 mm annually.

Tectonics

Tectonics (from the Late Latin tectonicus from the Greek τεκτονικός, "pertaining to building") is concerned with the processes which control the structure and properties of the Earth's crust, and its evolution through time. In particular, it describes the processes of mountain building, the growth and behavior of the strong, old cores of continents known as cratons, and the ways in which the relatively rigid plates that comprise the Earth's outer shell interact with each other. Tectonics also provides a framework to understand the earthquake and volcanic belts which directly affect much of the global population. Tectonic studies are important for understanding erosion patterns in geomorphology and as guides for the economic geologist searching for petroleum and metallic ores.

Main types of tectonic regime

Extensional tectonics

Extensional tectonics is associated with the stretching and thinning of the crust or lithosphere. This type of tectonics is found at divergent plate boundaries, in continental rifts, during and after a period of continental collision caused by the lateral spreading of the thickened crust formed, at releasing bends in strike-slip faults, in back-arc basins and on the continental end of passive margin sequences where a detachment layer is present.

Planet Earth

Planet Earth may refer to Earth, the third planet from the sun.

Planet Earth may also refer to:

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