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The '''Variscan''' or '''Hercynian orogeny''' is a geologic mountain-building event recorded in the European mountains and hills called the [[Variscan Belt]]. This occurred in early [[Paleozoic]] times (from ~390Ma to ~310Ma) and reflects [[continental collision]] between Laurasia and Gondwana to form [[Pangea]]. This early collision was a precursor to the collision that caused the Variscan-[[Allegheny]]-[[Ouachita]] [[orogeny]] in [[Pennsylvanian]] times. |
The '''Variscan''' or '''Hercynian orogeny''' is a geologic mountain-building event recorded in the European mountains and hills called the [[Variscan Belt]]. This occurred in early [[Paleozoic]] times (from ~390Ma to ~310Ma) and reflects [[continental collision]] between Laurasia and Gondwana to form [[Pangea]]. This early collision was a precursor to the collision that caused the Variscan-[[Allegheny]]-[[Ouachita]] [[orogeny]] in [[Pennsylvanian]] times. |
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The European Variscan Belt (also called Variscides) includes the mountains of [[Portugal]] and western [[Spain]], |
The European Variscan Belt (also called Variscides) includes the mountains of [[Portugal]] and western [[Spain]], south-western [[Ireland]], south-western [[England]] and [[Pembrokeshire]]. Its effects are present in [[France]] from [[Brittany]], below the [[Paris Basin (geology)|Paris Basin]] to the [[Ardennes]], the [[Massif Central]], the [[Vosges]] and [[Corsica]]. It shows in [[Sardinia]] in [[Italy]] and in [[Germany]] where the [[Hunsrück]], the [[Black Forest]] and [[Harz Mountains]] remain as testimony. Also, in the [[Czech Republic]] the [[Bohemia|Bohemian Massif]] is the eastern end of the Variscan belt of crustal deformation in Europe. The Variscan was contemporaneous with the [[Acadian orogeny]] in the [[United States]], which raised the [[Appalachian Mountains]]; then continuous with the Caledonides, the mountains raised by the [[Caledonian orogeny]]. |
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The name, Variscan, comes from the |
The name, Variscan, comes from the Medieval Latin name for the district, Variscia, which undoubtedly comes from the name of a Germanic tribe, the [[Varisci]]. [[Variscite]], a rare green mineral found in the region and first discovered in the [[Vogtland]] district of [[Saxony]] in [[Germany]], which is in the Variscan belt, has the same etymology. Hercynian, on the other hand, derives from the [[Harz Mountains]], in northern Germany. |
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Plate convergence that caused the [[Caledonian orogeny]] in the [[Silurian]] continued to from the Variscan orogeny in the succeeding [[Devonian]] (ca. 416-359 Ma) and [[Carboniferous]] (ca. 359-299 Ma) Periods. Both resulted in the assembly of a |
Plate convergence that caused the [[Caledonian orogeny]] in the [[Silurian]] continued to from the Variscan orogeny in the succeeding [[Devonian]] (ca. 416-359 Ma) and [[Carboniferous]] (ca. 359-299 Ma) Periods. Both resulted in the assembly of a super-continent, [[Pangaea]], which was essentially complete by the end of the Carboniferous. |
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In the [[Ordovician]] Period, a land mass, which |
In the [[Ordovician]] Period, a land mass, which has been named [[Gondwana]], straddled the space between the [[South Pole]] and the [[Equator]] on one side of the globe. Off to the west were three other masses: [[Laurentia]], [[Siberia]] and [[Baltica]], located as if on the vertices of a triangle. To the south of them was a large archipelago, the [[terrane]], [[Avalonia]]. |
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By the end of the [[Silurian]], [[oceanic spreading]] to the south of Avalonia had pushed the latter into north Laurentia, creating the Caledonide mountains. In the succeeding [[Devonian]], the [[Iapetus Ocean]] between Avalonia and Laurentia entirely closed, joining the two masses and thrusting up the northern [[Appalachians]] in the [[Acadian orogeny]]. Contemporaneously, the archipelago of southern Europe, which had been between Avalonia and Gondwana, was pushed into Avalonia, creating a second range, the Variscan, to the east of the Caledonide/Appalachian. Both ran in a NW-SE direction. |
By the end of the [[Silurian]], [[oceanic spreading]] to the south of Avalonia had pushed the latter into north Laurentia, creating the Caledonide mountains. In the succeeding [[Devonian]], the [[Iapetus Ocean]] between Avalonia and Laurentia entirely closed, joining the two masses and thrusting up the northern [[Appalachians]] in the [[Acadian orogeny]]. Contemporaneously, the archipelago of southern Europe, which had been between Avalonia and Gondwana, was pushed into Avalonia, creating a second range, the Variscan, to the east of the Caledonide/Appalachian. Both ran in a NW-SE direction. |
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The Variscan belt was in place by the early Carboniferous. By the end of the Carboniferous, Gondwana had united with Laurentia. Siberia was approaching from the northeast, separated from Laurentia only by shallow waters. Collision with Siberia produced the [[Ural Mountains]] in the latest Paleozoic. In the [[Triassic]] Period of the [[Mesozoic]] Era, animals could move without oceanic impediment from Siberia over the North Pole to Antarctica over the South Pole. This traversability especially assisted the |
The Variscan belt was in place by the early Carboniferous. By the end of the Carboniferous, Gondwana had united with Laurentia. Siberia was approaching from the northeast, separated from Laurentia only by shallow waters. Collision with Siberia produced the [[Ural Mountains]] in the latest Paleozoic. In the [[Triassic]] Period of the [[Mesozoic]] Era, animals could move without oceanic impediment from Siberia over the North Pole to Antarctica over the South Pole. This traversability especially assisted the spread of the mobile [[Dinosaurs]]. In the [[Cenozoic]] Era, [[Laurasia]] divided from Gondwana, while Siberia with Baltica split from Laurentia. As a consequence, the Variscan Belt around the then periphery of Baltica ended up many hundreds of miles from the Appalachians. |
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==External links== |
==External links== |
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Revision as of 20:21, 23 November 2005
The Variscan or Hercynian orogeny is a geologic mountain-building event recorded in the European mountains and hills called the Variscan Belt. This occurred in early Paleozoic times (from ~390Ma to ~310Ma) and reflects continental collision between Laurasia and Gondwana to form Pangea. This early collision was a precursor to the collision that caused the Variscan-Allegheny-Ouachita orogeny in Pennsylvanian times.
The European Variscan Belt (also called Variscides) includes the mountains of Portugal and western Spain, south-western Ireland, south-western England and Pembrokeshire. Its effects are present in France from Brittany, below the Paris Basin to the Ardennes, the Massif Central, the Vosges and Corsica. It shows in Sardinia in Italy and in Germany where the Hunsrück, the Black Forest and Harz Mountains remain as testimony. Also, in the Czech Republic the Bohemian Massif is the eastern end of the Variscan belt of crustal deformation in Europe. The Variscan was contemporaneous with the Acadian orogeny in the United States, which raised the Appalachian Mountains; then continuous with the Caledonides, the mountains raised by the Caledonian orogeny.
The name, Variscan, comes from the Medieval Latin name for the district, Variscia, which undoubtedly comes from the name of a Germanic tribe, the Varisci. Variscite, a rare green mineral found in the region and first discovered in the Vogtland district of Saxony in Germany, which is in the Variscan belt, has the same etymology. Hercynian, on the other hand, derives from the Harz Mountains, in northern Germany.
Plate convergence that caused the Caledonian orogeny in the Silurian continued to from the Variscan orogeny in the succeeding Devonian (ca. 416-359 Ma) and Carboniferous (ca. 359-299 Ma) Periods. Both resulted in the assembly of a super-continent, Pangaea, which was essentially complete by the end of the Carboniferous.
In the Ordovician Period, a land mass, which has been named Gondwana, straddled the space between the South Pole and the Equator on one side of the globe. Off to the west were three other masses: Laurentia, Siberia and Baltica, located as if on the vertices of a triangle. To the south of them was a large archipelago, the terrane, Avalonia.
By the end of the Silurian, oceanic spreading to the south of Avalonia had pushed the latter into north Laurentia, creating the Caledonide mountains. In the succeeding Devonian, the Iapetus Ocean between Avalonia and Laurentia entirely closed, joining the two masses and thrusting up the northern Appalachians in the Acadian orogeny. Contemporaneously, the archipelago of southern Europe, which had been between Avalonia and Gondwana, was pushed into Avalonia, creating a second range, the Variscan, to the east of the Caledonide/Appalachian. Both ran in a NW-SE direction.
The Variscan belt was in place by the early Carboniferous. By the end of the Carboniferous, Gondwana had united with Laurentia. Siberia was approaching from the northeast, separated from Laurentia only by shallow waters. Collision with Siberia produced the Ural Mountains in the latest Paleozoic. In the Triassic Period of the Mesozoic Era, animals could move without oceanic impediment from Siberia over the North Pole to Antarctica over the South Pole. This traversability especially assisted the spread of the mobile Dinosaurs. In the Cenozoic Era, Laurasia divided from Gondwana, while Siberia with Baltica split from Laurentia. As a consequence, the Variscan Belt around the then periphery of Baltica ended up many hundreds of miles from the Appalachians.