Alpine orogeny

The Alpidic orogeny refers to the date last global mountain building phase of Earth's history in which the Alps were formed.

The process of this orogeny is from the Cretaceous of the strongest uplift in the Miocene period about 20 million years ago to modern times, including a period of 100 million years, and decays for about 5 million years. The glaciations of the Pleistocene in the last 2 million years then significantly influenced the look of today's mountains.

In this orogeny the Alpidic mountain belt with Atlas, Pyrenees, Balearic Islands, Alps, Carpathians, Apennines, Rhodopes, Balkans, Anatolia, the Caucasus, the Hindu Kush, Karakoram, Himalaya was formed up to the western mountains of Indochina and Malaysia.

The American Cordillera was also written by plate tectonic processes this time, the formation of which is however considered as a separate orogeny.

• 2.1 Development in the Paleogene
• 2.2 Development of the Neogene and future

Previous geological processes

Prehistory

In the Precambrian gneiss central nuclei of the Zillertal Alps and the eastern Hohe Tauern mountains are parts of the Neoproterozoic supercontinent Rodinia, which have an age of 1000 million years ago.

Since the breakup of this supercontinent - say, from 750 mya ( million years ago) - had been the ocean floor rocks of the Alps later. Around 550 mya they share in the coastal shelf of Gondwana and from 460 mya, they were then in Rheischen ocean from which they, partly protruded about 420 mya as a volcanic island arc, the Hun - Terran. At the peak of the strongest phase of the Variscan orogeny before 360 mya, these islands were again immersed in the Rhea. The Alps were mya in the Permian from 300 eventually sediment field of Tethys in the east of Pangaea.

Development in the Triassic

In the Triassic, 250 mya to spread the mid-ocean ridge of the Tethys, but was subducted to the north beneath the coastal shelf of modern Turkey, Iran, Tibet and Indochina; this accretion to the continental shelf areas led to compression and, ultimately, to the uplift of the shelves on the sea surface. The long, thin continent fragment Cimmeria seceded from the northern edge of East Gondwana and rotated around a point in the current Carpathians. The volcanic island arc of the later Cimmerian fold belt arose in the southern coastal shelf of the young Eurasia.

The associated with the spread opening of the Tethys caused by the West - features oversized side shifts and trench formation in the regions of the old Variscan mountains - even violent volcanism in the Alpine continental shelf, in the north of the Apulian spur, and the Breton in the area of ​​present-day Pyrenees between Iberia Variscides and in Gibraltar; he reached the rift zone of the later Atlantic and reached even over yet, except for the northern Appalachians.

Development in the Jura

Before the southern coasts Cimmerias originated in the Jura from 200 mya, a deep ditch, which Tethysgraben, the west or transversely through the break-up of Pangaea, about the deep-sea area of ​​the newly established Piedmont Ocean to the Atlantic grave breach and the northern coast of South America West Gondwana went. The spreading itself Penninic Ocean in the west formed the Helvetic shelf, in the center of the trough area of ​​the sediment Penninikums, and in the east the Eastern Alpine shelf of Gondwana drifted with the Apulian Spur to the east.

Development in the Cretaceous

During the Lower Cretaceous from 145 mya now clearly separated North America, Greenland and Europe, the North Atlantic opened.

The progressive Cimmerian approach to South-East Europe and the Asian cratons, the opening of the North Atlantic Ocean and a number of relatively narrow oceanic basin (see above and r. ) Which were connected to each other via Transform faults, continues to be a complex interplay revealed across the decaying Pangaea.

Iberia broke away from Europe as a separate crustal fragment from and also the Apulian spur was separated by the emerging eastern Mediterranean from nunmehrigen Africa and urged now as self that have become micro- continent continues to face the southern edge of Europe, raising thereby the Austrian and Italian Eastern Alps above the sea level. Both first sections of the Pennine deep sea basin as well as the last remnants of the western Tethys ocean floor was subducted. In the area of the Carpathians and the Balkans strong volcanism developed.

The Alpine orogeny

Development in Paleogene

In the early Paleogene (66 mya ) collided split off from Africa Adriatic microplate with the pre- Alpine Europe. The line of the clash with the formation of the suture extends from the Aegean Sea on the region of the river Vardar in Macedonia, the Cliff zone of the Carpathians and the Penninic zone of the Alps, Piedmont and Corsica.

Africa drifted further to the north east and the Indian subcontinent came from the former southern continent Gondwana coming to Asia. To the Cretaceous-Tertiary boundary is now also highlighted the Western Alps of France and Switzerland from the western Helvetic shelf of the Piedmont Ocean, and from the northern coastal shelf of the young Mediterranean rose the Apennines and the Calabrian arc. Sardinia and Corsica parted from with a twisting motion. At the same time increased the older Variscan Mountains Central and Western Europe, from the time of Acadischen Gebirgsbildungsära, again on the sea surface of the reorganized Paratethys, and still form the western abutment to this plate tectonic events.

Development of the Neogene and future

In the Neogene from 23 mya the Paratethys, the northern marginal zone of the Tethys in Europe and Central Asia today, was gradually closed. Their remains are now silted Pannonian Sea, the Black Sea and the Caspian Sea. In the Oligocene fired again a crustal strain, rifts in the ocean floor spread and were formed back- arc basins. By changing directions of subduction and the sea floor spreading, there was a complex folding of the basement, which integrated the same time forming with molasses.

The current fourth global ice age, from 2.6 mya impressed with its alternating glacial and interglacial periods today's terrain structure.

The continental drift of the continental plates involved continues still, therefore the Alpidic orogeny is not yet complete. Alps and Himalayas grow in the range of millimeters per year slowly, but will at the same time of the exogenous geological processes ( eg erosion ) dismantled. In 50 million years, this tectonic process in the area of the Mediterranean, the Red Sea and the Persian Gulf will have formed new mountain ranges.

Rocks

The main rock stock in the high alpine and mountain regions are monotonous para- gneisses, which are metamorphosed clayey and sandy sediments, greywackes and tuffs. In it are often found amphibolites that have arisen from basalts. In these societies also igneous rock gneiss are very common. In the Silvretta and the Ötztal Alps is an older orthogneiss generation altpaläozoisches an intrusion event. Other, younger magmatic gneisses are penetrated, however, in the wake of the Variscan orogeny in the Carboniferous. Equal old granite gneisses occur, inter alia, in the crystalline masses of the Schladming Tauern and Seckauer Tauern and the Mürztaler Alps and are an indication of a first-time orogeny in earlier variszischer time ( mya to 420, supra ).