Pangaea

Pangaea, Pangaea different spelling, rarely Pangea ( from Ancient Greek πᾶν pan " all " and γαῖα gaia "earth", "land", ie literally "whole earth " ), was the last global super-continent of Earth's history.

It existed as a contiguous land mass before about 300 to 150 million years ago ( Carboniferous to Jurassic), ie in the section of the earth's history, in which the great mass extinction took place at the end of the Permian and evolved dinosaurs.

History of the term

The concept that the end of the Paleozoic, all the continents were united in a supercontinent, goes back to Alfred Wegener, who in 1912 published the idea first. He later extended this work to his famous book The Origin of Continents and Oceans, which was published in six editions from 1915. In the second, completely revised edition of 1920 for the first time the term appears Pangaea. The term was then used as input Pangaea in the German literature as well as in the English-language literature (especially by the symposium volume to a meeting of the American Association of Petroleum Geologists in November 1926). Alfred Wegener himself used the term only once in his works.

Formation

Pangaea was formed by the collision of Laurussia - the Old- Red- continent - and Gondwana - the Great Southern Continent - by closure of the Iapetus Ocean and the Rheischen - ocean.

The smaller peri- Gondwana elements Perunica, Armorica, but also the cratons of today's Siberia, Kazakhstan, North and South China, and several volcanic island arcs were other constituents. Surrounded by Pangaea was Panthalassa global ocean and its vast eastern bay, the Tethys.

Mountain building

In the course of collisions of continental blocks during the Palaeozoic and the raising of the damages caused by subduction geosynclines and deep-sea trenches led to the formation of many currently exist fold mountains and mountain building by accretion and volcanism.

Stark verfaltete and worn Terrane Avalonias - from the first collision with Baltica and the second collision with Laurentia - can be found in Newfoundland, England, Northern Germany, in the Carpathian arc and on the Balkan peninsula and in Spain and Morocco.

The first major section of this Acadian Gebirgsbildungsära is the Caledonian orogeny - taconic in the late Ordovician and Silurian in Northern Europe ( 444-416 mya ). Were affected

• The east coast Laurentias ( Taconic orogeny )
• Northwestern parts of Europe: Northern Ireland, North and West Wales, Scotland and Norway ( Caledonian orogeny )

Tens of millions of years later ( the phases may overlap ) followed the Acadian orogeny in the Devonian - Variscan and Carboniferous ( 390-310 mya ).

• In Western and Central Europe, the mountain belt of the Variscan arose. The Variscan mountains ranged from present-day Portugal and western Spain to South West of Ireland, Cornwall and South Wales ( Pembrokeshire, Gower and the Vale of Glamorgan ). In continental Europe, the mountains describes a wide arc: Armorican Massif in Brittany, Central France, Ardennes, Rhenish Slate Mountains; Odenwald, Spessart and resin; Thuringian- Franconian Middle Mountains, Ore Mountains, and finally on the eastern edge the Bohemian Massif. To the south a mountainous band from the Black Forest, the Vosges Mountains and the Massif Central pulls up to Corsica and Sardinia.

• At the Canadian Shield in the northern Appalachians arose, first in the Acadian and later in the Alleghenischen orogeny. In Texas and Mexico, there was just as much as folds in Nevada and Arkansas ( Ouachita Mountains ).

In the Triassic ( 250 mya from ) the layers of the Germanic development formed in the later Middle Europe by the erosion of Variscan while there were massive deposits of the Tethys in the area of present-day Mediterranean and the Alps. Then part Laurussias - - In Russia, the squeezing of the Russian craton Balticas completed with the Western Siberian and Kazakh Kraton, which had already formed the Urals.

Tectonic correlates and consequences

All mountain ranges of these epochs are ready sedimented by erosion that the former six to eight thousand meters peaks are visible at best as mountains or hull form layers in later orogenies. Appears particularly interesting is the fact that sediments of the Iapetus Ocean - are detectable as suture both in Appalachia and in the Caledonian mountains. This means that exactly at the original welding zone of the continental blocks after 150 million years ago - their break happened - at least in part.

As with any mountain building, it also came here for the raising of older rock layers: In the Bohemian Massif of the Waldviertel in Lower Austria gneisses were the Variscan uplift events revealed folded out of the supercontinent Rodinia from before 1.1 billion years or pushed over younger rock layers.

The Variscan mountain building also had magma rises from the depths of the effect of the different places have led to ore deposits. Due to the reductions occurring in the foothills of the geosyncline are there too worn masses of rock debris and fine sediments were deposited (see also sedimentary basins ). This is due, inter alia, processes the Ruhr its numerous coal seams.

Resolution

Due to plate tectonics, Pangaea broke up in the Jura - before about 150 Ma - the formation of the Paratethys in today's Central Europe and Southern Europe seems to get in the big continents Laurasia and Gondwana, from which it was created and later in the Cretaceous period - before about 135 Ma - in the course the spreading of the Atlantic and the transformation of the Tethys to the Indian Ocean and Southern Ocean into the continents we know today disintegrated.

The Bohemian Massif, but also the other parts of the southern Variscides, made ​​- starting before about 100 Ma - the " abutment " to the African plate on their way north. This collision threw and throws among many other things the Alps.

These younger mountain ranges are in particular the alpidischen mountain ranges of the Alps, the Apennines, the Carpathians, the Balkan Mountains and the Pyrenees in Europe, the Himalayas in Asia, the Atlas Mountains in North Africa or the Rocky Mountains in North America and the Andes in South America, which is about to the chalk 65 million years ago raised - tertiary boundary from the primeval ocean.

The mantle beneath Pangaea former position is still hot. Because of the related convection of the magma Africa is about ten feet higher than the other continents.