Variscan orogeny in the context of "Caledonian orogeny"

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⭐ Core Definition: Variscan orogeny

The Variscan orogeny or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. It remains visible today as a series of isolated massifs, including the Ardennes, Bohemian Massif, Vosges-Black Forest, Armorican Massif, Cornubian Massif, Massif Central, and Iberian System. These are interspersed with Mesozoic and Cenozoic sedimentary basins. The chain also crops out in southern Ireland and was later incorporated into the Alpine orogeny (external crystalline massifs) and Pyrenean orogeny. These ancient massifs form the pre-Permian basement of western and Central Europe, part of a larger mountain system stretching from the Ural Mountains in Russia to the Appalachian Mountains in North America.

The chain originated from the convergence and collision of three continental masses: the microcontinent Armorica and the supercontinents Protogondwana and Laurussia (a union of Laurentia and Baltica from the Caledonian orogeny). This convergence contributed to the formation of the supercontinent Pangaea.

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Variscan orogeny in the context of Măcin Mountains

The Măcin Mountains (Romanian: Munții Măcin) is a mountain range in Tulcea County, Romania. Part of the Northern Dobruja Massif, they are located between Danube River to the north and west, Taița River and Culmea Niculițelului to the east and Casimcea Plateau to the south. Seen from the Danube, they seem only low hills. However, they are a mountainous region.

The Măcin Mountains are one of the oldest in Romania, being formed in the second part of the Paleozoic, in the Carboniferous and Permian, during the Hercynian orogeny. The predominant rock is granite. Erosion (caused by the difference of temperature) has created steep slopes, with the aspect of ruins.

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Variscan orogeny in the context of Metamorphic rock

Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F) and, often, elevated pressure of 100 megapascals (1,000 bar) or more, causing profound physical or chemical changes. During this process, the rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous, sedimentary, or existing metamorphic rock.

Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture. They may be formed simply by being deeply buried beneath the Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and distortion. Metamorphic rock can be formed locally when rock is heated by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth's crust.

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Variscan orogeny in the context of Gugh

Gugh (/ɡj/ GHEW; Cornish: Keow, lit.'hedge banks') could be described as the sixth inhabited island of the Isles of Scilly, but is usually included with St Agnes with which it is joined by a sandy tombolo known as "The Bar" when exposed at low tide. The island is only about 1 km (0.62 mi) long and about 0.5 km (0.31 mi) wide, with the highest point, Kittern Hill, at 34 m (112 ft). The geology consists of Hercynian granite with shallow podzolic soils on the higher ground and deeper sandy soils on the lower ground. The former Gugh farm is just north of the neck across the middle of the island between the two hills. The two houses were designed and built in the 1920s by Charles Hamlet Cooper.

The island lies within the Isles of Scilly Heritage Coast, is in the Isles of Scilly Area of Outstanding Natural Beauty and is managed by the Isles of Scilly Wildlife Trust. Vegetation cover is mainly wind-pruned heath or dense bracken and bramble with a small area of coastal grassland formed over blown sand which has accumulated near the bar.

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Variscan orogeny in the context of Paris Basin

The Paris Basin (French: Bassin parisien) is one of the major geological regions of France. It developed since the Triassic over remnant uplands of the Variscan orogeny (Hercynian orogeny). The sedimentary basin, no longer a single drainage basin, is a large sag in the craton, bordered by the Armorican Massif to the west, the Ardennes-Brabant axis to the north, the Massif des Vosges to the east, and the Massif Central to the south.

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Variscan orogeny in the context of List of subranges of the Appalachian Mountains

The following is a list of subranges within the Appalachian Mountains, a mountain range stretching ~2,050 miles from Newfoundland and Labrador, Canada to Alabama, US. The Appalachians, at their initial formation, were a part of the larger Central Pangean Mountains along with the Scottish Highlands, the Ouachita Mountains, and the Anti-Atlas Mountains. The modern ranges were formed and/or deformed by the Acadian, Caledonian, Alleghenian, Mauritanide and Variscan orogenies with the Alleghenian orogeny being the most notable to the modern Appalachians.

The Appalachians are also subdivided by a number of large plateaus and additional subplateus. These are commonly not considered subranges although they do contain some features referred to as mountains which are assigned to both their geographic "range" and the more general Appalachian Mountains. These plateaus, such as the Allegheny Plateau, are considered provinces of the Appalachian Highlands and the mountains assigned to them are instead considered pieces of dissected plateaus.

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