The process of this orogeny extends from the Cretaceous period through the strongest uplift phase in the Miocene around 20 million years ago to modern times, spans a period of around 100 million years, and has been subsiding for around 5 million years. The ice ages of the Pleistocene in the last 2 million years then significantly shaped the appearance of today's mountains.
During this mountainous formation, the Alpidic mountain belt (also called the Alpidic mountain system ) with the Atlas , Pyrenees , Balearic Islands , Alps, Carpathians , Apennines , Dinaric mountains , Rhodopes , Balkans , Taurus , Caucasus , Zāgros , Kuhrud , Elburs , Kopet-Dag , Suleiman- Mountains , Hindu Kush , Karakoram , Himalaya to the western mountains of Indochina and Malaysia . The American Cordillera was also created by plate tectonic processes of this time, but its formation is regarded as an independent orogeny.
Previous geological processes
Since the disintegration of this supercontinent - from around 750 mya (million years) - the rocks of the later Alps had been the seabed. Around 550 mya they had a share of the Gondwana coast shelf and from 460 mya they were then in the Rhine Ocean , from which they protruded in places around 420 mya as a volcanic island arc , the Hun Terran . At the height of the strongest phase of the Variscan mountain formation before 360 mya, these islands were sunk again in the Rhea . In the Permian from 300 mya the Alps finally became a sediment area of the Tethys in the east of Pangea .
Development in the Triassic
In the Triassic from 250 mya the mid-ocean ridge of the Tethys spread, but was subducted in the north under the coastal shelf of today's Turkey , Iran , Tibet and Indochina ; this accretion to the shelf areas led to the compression and ultimately also to the lifting of the shelf above the sea surface. The long and thin continent fragment Cimmeria split off from the northern edge of eastern Gondwana and rotated around a point in the area of the current Carpathian Mountains . The volcanic island arch of the later Cimmerian fold belt rose in the southern coastal shelf of young Eurasia .
The opening of the Tethys to the west that accompanied the spreading caused - in addition to extensive lateral shifts and rift formations in the regions of the old Variscan mountains - also violent volcanism in the alpine shelf, in the north of the Apulian spur , in the area of today's Pyrenees between Iberia and the Breton Variscides and in Gibraltar ; it reached the rift zone of the later Atlantic and even spread to the northern Appalachians .
Development in the Jura
Off the southern coast of Cimmeria, a deep rift was formed in the Jura from 200 mya, the Tethys Trench, which stretched west across the disintegrating Pangea, over the deep sea area of the newly formed Pennine Ocean to the Atlantic rift valley and the north coast of South America and western Gondwana. The spreading Pennine Ocean formed the Helvetic Shelf in the west , the Penninic sediment area in the center of the trough , and the Eastern Alpine Shelf in the east, which drifted eastward with the Apulian spur of Gondwana.
Development in Chalk
The progressive Cimmerian rapprochement with Southeast Europe and the Asian cratons , the opening of the North Atlantic Ocean and a number of relatively narrow oceanic basins (see above and right) that were connected by transform faults continued to result in a complex interplay across the disintegrating Pangea .
Iberia broke away from Europe as an independent crust fragment and the Apulian spur was also separated from what is now Africa by the emerging eastern Mediterranean and now continued to push towards the southern edge of Europe as an independent microcontinent, lifting the eastern Alps of Austria and Italy above sea level. In the process, both the first sections of the Pennine deep-sea basin and the last remnants of the westernmost Tethys ocean floor were subducted ( Altalpid mountain formation or Eoalpine orogeny ). In the area of the Carpathians and the Balkans , strong volcanism developed.
The alpine orogeny
Development in the Paleogene
In the early Paleogene (from 66 mya ) the Adriatic microplate split off from Africa collided with pre-Alpine Europe ; in comparison to the prehistory that took place in the Cretaceous period, this process in the Alps is also known as Jungalpid mountain formation . The line of collision with the formation of the suture runs from the Aegean Sea over the region of the Vardar River in North Macedonia , the cliff zone of the Carpathian Mountains and the Penninic zone of the Alps, Piedmont to Corsica .
Africa continued to drift to the northeast and the Indian subcontinent , coming from the former southern continent Gondwana , met Asia . At the turn of the Cretaceous-Palaeogene , the western Alps of France and Switzerland rose from the Pennine Ocean and the Apennines and the Calabrian Arc rose from the northern edge of the young Mediterranean . In the meantime, Sardinia and Corsica detached themselves from the European continental bloc in a counter-clockwise rotation.
Development in the Neogene and Future
In the Neogene from 23 mya the Paratethys, the northern edge zone of the Tethys in Europe and what is now Central Asia, was gradually closed. Their remains are the now silted Pannonian Sea , the Black Sea and the Caspian Sea . In the Oligocene , crustal expansion set in again, rifts in the ocean floors spread and back-arc basins formed . The changing directions of subduction and ocean floor spreading resulted in a multilayered folding of the basement , which included the molasses that were forming at the same time .
The continental drift of the continental plates involved is still going on, which is why the alpine mountain formation is not yet complete. The Alps and Himalayas continue to grow slowly by the millimeter per year, but at the same time they are degraded again by exogenous geological processes (e.g. erosion ). In 50 million years, this tectonic process will have formed new mountain ranges in the Mediterranean, Red Sea and Persian Gulf regions .
The main rock in the central alpine high and low mountain regions are uniform para- gneisses , which are metamorphosed clayey and sandy sediments, greywacke and tuff . Amphibolites that arose from basalts are often found in them. In these rock communities, igneous orthogneiss are also very common. In the Silvretta and the Ötztal Alps, an older generation of orthogneiss documents an ancient Paleozoic intrusion event . Other, younger igneous gneisses, however, penetrated in the wake of the Variscan mountain formation in the Carboniferous . The same old granite gneisses come u. a. in the crystalline masses of the Schladminger Tauern and Seckauer Tauern and in the Mürz Valley Alps and are an indication of a first orogenesis in the early Variscan period (around 420 mya, see above).
The powerful marine sediments and shelf carbonates of the Tethys can be found as rocks of the Helvetic Mountains in the west and the highest tectonic unit of the Northern Limestone Alps in the Eastern Alps and the Dolomites in the Southern Alps .
- Geological history of Lower Austria
- plate tectonics
- Taconic orogeny
- Caledonian orogeny
- Variscan orogenesis
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- SM Schmid, B. Fügenschuh, E. Kissling, R. Schuster: Tectonic map and overall architecture of the Alpine orogen . In: Eclogae geologicae Helvetiae . tape 97 . Birkhäuser Verlag, 2004, ISSN 0012-9402 , p. 93-117 . PDF
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- The world 100 million years ago: at the place of the Alps is deep sea
- The earth 50 million years ago: The European mountains and the Himalayas began to form.
- The world 14 million years ago: The Paratethys has formed and is beginning to silt up.
- Establishment of the Ostalpen Geological Federal Institute Vienna (archived website)
- Shadows of old continents - the oldest parts of Austria ( Memento from August 28, 2011 in the Internet Archive )
- Mountain Formations in Europe
- The geological development of the Central Alps by A.Ebert, 2001
- RICHTER, L .: geology and geography of the Alps - an overview . In: KENKMANN, T. (Ed.): Excursion guide to the main excursion 2000 - Geology and physical geography of the western and central Alps . Work reports, issue 56 . Geographical Institute of the Humboldt University of Berlin, 2001, ISSN 0947-0360 , p. 11 .