Orogeny


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orogeny

[ȯ′räj·ə·nē]
(geology)
The process or processes of mountain formation, especially the intense deformation of rocks by folding and faulting which, in many mountainous regions, has been accompanied by metamorphism, invasion of molten rock, and volcanic eruption; in modern usage, orogeny produces the internal structure of mountains, and epeirogeny produces the mountainous topography. Also known as orogenesis; tectogenesis.

Orogeny

 

the process of the formation of mountains resulting from vertical tectonic movements, whose rate exceeds that of the exogenous process of destruction and removal (erosion) of rock or the process of buildup of sediments (accumulation), which lead to the leveling of the earth’s surface. Orogeny is characteristic of active regions of the earth.


Orogeny

 

(also orogenesis), a geological term introduced by the American geologist G. Gilbert in 1890 to designate mountain building and intense deformation by folding and faulting. Gilbert singled out orogenic movements of the earth’s crust and contrasted them to epeirogenic movements, that is, slow upward and downward movements.

The concept of orogeny was further developed by the French geologist G.-E. Haug, who in 1907 proposed that orogeny be distinguished only within geosynclinal regions. Subsequently, in 1919, the German geologist H. Stille hypothesized that the chief result of orogeny was not the formation of mountains but rather the formation of folds.

When the term “orogeny” was introduced, the crumpling of layers of rock into folds was believed to lead directly to the formation of mountains. It was later discovered that mountains are not created by folding of the earth’s crust and that mountain formation often occurs independently of folding. Soviet geologists thereupon began using the term “orogeny” to designate only the process of mountain formation. They made a distinction between epigeosynclinal (postfolding) orogeny and epiplatform orogeny, which is not preceeded by geosynclinal subsidence and folding-overthrust deformation. Outside the USSR, orogeny is still often understood in the Stille interpretation, that is, as the aggregate of fold and mountain formation.

V. E. KHAIN

References in periodicals archive ?
These two blind thrust faults are probably linked to a single event of deformation in response to the Himalayan Orogeny.
The maximum principal stress appeared to be a horizontal compression force perpendicular to the discontinuity system, which was most likely due to the residual stresses derived from the Apuan Alps' orogeny process.
This tectonic scenario would fit well with that of south-central Maine in the Carboniferous as the peak period of collisional tectonism in the region (the Acadian orogeny) preceded the intrusion of the Litchfield pluton by about 50 million years (Bradley et al.
The plutonometamorphic extensional dome was subsequently deformed by the Ocloyic orogeny (Middle/Late Ordovician-Devonian).
The enigmatic Finnmarkian event in the North of Norway at about 489 Ma, whether a true orogeny, an arc-continent collision followed by subduction, or just a transtensional mega-shear zone certainly provided metamorphic shale material heated between 150 and 550[degrees]C and sideways thrust for lithological facies folding and for spreading the allochtons as far as Oslo.
For a mini-version of this thrill, visit a dealership in granite countertops, where you can go out in the back lot and see 8-foot polished slabs of beautiful stone with all the dynamism of churning orogeny preserved like a snapshot.
The papers are organized into sections on the Palaeoproterozoic terranes from the West African craton and their reworking, the Pan- African orogeny along the boundaries of the West African craton, the late Neoproterozoic--early Paleozoic extension along the West African craton and the Peri-Gondwanan terranes, the Variscan orogeny along the West African craton, and the Cenozoic situation along the boundaries of the West African craton.
These beds were only marginally altered by the Taconic orogenic phase of Appalachian tectonic history (Middle Ordovician-Silurian), but underwent thin-skinned folding and thrusting at a later time during the Late Permian Alleghanian Orogeny Hatcher, 1987).
The Disentis region contains two remnants of the Variscan (Hercynian) orogeny within the younger Alpine orogeny: the Aar massif to the north and the Gotthard massif to the south.
A second orogeny in the Late Cretaceous culminated with the discordant intrusion of the tonalitic Antioquian batholith.
The Surghar Range is an arcuate mountain belt of the outermost Himalayan orogeny and constitutes the eastern closure of the Trans-Indus Salt ranges of northwest Pakistan, (Ali et al., 2014) (Fig.
The Upper Paleozoic, Permian-Carboniferous basins exist in the study area, forming narrow trough-like, often asymmetric depressions already independent on the course of the main Variscan orogeny divides.