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The relative movement of the plates typically ranges from zero to 10 cm annually. Faults tend to be geologically active, experiencing earthquakes, volcanic activity, mountain-building, and oceanic trench formation. Tectonic plates are composed of the oceanic lithosphere and the thicker continental lithosphere, each topped by its own kind of crust.
The "Bullard's Fit" of the Iapetus Ocean suture zone. Approximate location of Mesoproterozoic (older than 1.3 Ga) cratons in South America and Africa. The São Luís and the Luis Alves cratonic fragments are shown (Brazil), but the Arequipa–Antofalla craton, the Saharan Metacraton and some minor African cratons are not.
A tectonic phase or deformation phase is in structural geology and petrology a phase in which tectonic movement or metamorphism took place. Tectonic phases can be extensional or compressional in nature. When numerous subsequent compressional tectonic phases share the same geodynamic cause (usually some plate tectonic mechanism) this is called ...
This paradoxically results in divergence which was only incorporated in the theory of plate tectonics in 1970, but still results in net destruction when summed over major plate boundaries. [2] Divergent boundaries are areas where plates move away from each other, forming either mid-ocean ridges or rift valleys. These are also known as ...
Schematic diagram showing the physical processes inside the Earth that lead to the generation of magma. Partial melting begins above the fusion point. Map showing approximate location of many current hotspots and the relationship to current tectonic plates and their boundaries and movement vectors
The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, which ride on the fluid-like solid the asthenosphere. Plate motions range from 10 to 40 millimetres per year (0.4 to 1.6 in/year) at the Mid-Atlantic Ridge (about as fast as fingernails grow), to about 160 millimetres per year (6.3 in ...
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 ...
River erosion can be driven by tectonic uplift, climate, or potentially both mechanisms. It is difficult in many areas, however, to decisively pinpoint whether tectonism or climate change can individually drive tectonic uplift, enhanced erosion, and therefore terrace formation. In many cases, simplifying the geologic issue to tectonic-driven vs ...