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Plate tectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building') [1] is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago.
The plate theory is a model of volcanism that attributes all volcanic activity on Earth, even that which appears superficially to be anomalous, to the operation of plate tectonics. According to the plate theory, the principal cause of volcanism is extension of the lithosphere.
The continental crust on the downgoing plate is deeply subducted as part of the downgoing plate during collision, defined as buoyant crust entering a subduction zone. An unknown proportion of subducted continental crust returns to the surface as ultra-high pressure (UHP) metamorphic terranes, which contain metamorphic coesite and/or diamond plus or minus unusual silicon-rich garnets and/or ...
These plates are destroyed by subduction into the mantle at subduction zones. During the early Archean (about 3.0 Ga) the mantle was much hotter than today, probably around 1,600 °C (2,910 °F), [56]: 82 so convection in the mantle was faster. Although a process similar to present-day plate tectonics did occur, this would have gone faster too.
This is due to Earth's high erosional rates and the subduction and subsequent destruction of tectonic plates throughout its 4.5 Ga history. [12] Furthermore, during its existence the primordial crust is thought to have been regularly broken and re-formed by impacts involving other planetesimals. [ 13 ]
Scientists have known that the collision of the two tectonic plates, which began roughly 60 million years ago, caused the edge of the Eurasian plate to buckle, bulging and twisting into what we ...
However, an alternative view proposes that Earth never experienced a vertical tectonic phase and that plate tectonics have been active throughout its entire history. [25] [26] [27] During this time, the Earth's crust cooled enough that rocks and continental plates began to form.
Supervolcano – Volcano that has had an eruption with a volcanic explosivity index (VEI) of 8; Trans-Mexican Volcanic Belt – Active volcanic belt that covers central-southern Mexico; Volcanic arc – Chain of volcanoes formed above a subducting plate