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The Vine–Matthews–Morley hypothesis, also known as the Morley–Vine–Matthews hypothesis, was the first key scientific test of the seafloor spreading theory of continental drift and plate tectonics. Its key impact was that it allowed the rates of plate motions at mid-ocean ridges to be computed.
Diagram of a mid-ocean ridge showing ridge push near the mid-ocean ridge and the lack of ridge push after 90 Ma. Ridge push is the result of gravitational forces acting on the young, raised oceanic lithosphere around mid-ocean ridges, causing it to slide down the similarly raised but weaker asthenosphere and push on lithospheric material farther from the ridges.
This article describes techniques; for a history of the movement of tectonic plates, see Geological history of Earth.. Plate reconstruction is the process of reconstructing the positions of tectonic plates relative to each other (relative motion) or to other reference frames, such as the Earth's magnetic field or groups of hotspots, in the geological past.
Earth's lithosphere, the rigid outer shell of the planet including the crust and upper mantle, is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault): convergent, divergent, or transform ...
Obduction zones occurs when the continental plate is pushed under the oceanic plate, but this is unusual as the relative densities of the tectonic plates favours subduction of the oceanic plate. This causes the oceanic plate to buckle and usually results in a new mid-ocean ridge forming and turning the obduction into subduction. [citation needed]
Plate motion based on Global Positioning System (GPS) satellite data from NASA JPL. Each red dot is a measuring point and vectors show direction and magnitude of motion. Tectonic plates are able to move because of the relative density of oceanic lithosphere and the relative weakness of the asthenosphere.
Extensional tectonics is associated with the stretching and thinning of the crust or the 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 ...
Mantle convection is the very slow creep of Earth's solid silicate mantle as convection currents carry heat from the interior to the planet's surface. [2] [3] Mantle convection causes tectonic plates to move around the Earth's surface. [4] The Earth's lithosphere rides atop the asthenosphere, and the two form the components of the upper mantle ...