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Lopian orogeny – Archean orogeny – Formation of two different types of terrain compatible with plate tectonic concepts. One is a belt of high-grade gneisses formed in a regime of strong mobility, while the other is a region of granitoid intrusions and greenstone belts surrounded by the remnants of a Saamian substratum, (2.9–2.6 Ga)
Orogeny typically produces orogenic belts or orogens, which are elongated regions of deformation bordering continental cratons (the stable interiors of continents). Young orogenic belts, in which subduction is still taking place, are characterized by frequent volcanic activity and earthquakes.
An orogenic belt, orogen, or mobile belt, [a] is a zone of Earth's crust affected by orogeny. [2] An orogenic belt develops when a continental plate crumples and is uplifted to form one or more mountain ranges; this involves a series of geological processes collectively called orogenesis. [3] [4]
A number of rock types have been suggested as the source of orogenic gold, but due to the variability of host rocks in Earth’s history and deposit-scale, their relation to Earth-scale gold formation processes is unclear. [12] Furthermore, age dating of the deposits and their host rocks shows that there are large time gaps in their formation.
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 ...
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The Alpine orogeny is caused by the continents Africa, Arabia and India and the small Cimmerian Plate colliding (from the south) with Eurasia in the north. Convergent movements between the tectonic plates (the African Plate, the Arabian Plate and the Indian Plate from the south, the Eurasian Plate and the Anatolian Sub-Plate from the north, and many smaller plates and microplates) had already ...