Gondwana

Supercontinent formed at the any end of the Néoprotérozoïque (-   600 million years) and which started has to fracture with the Jurassic (-   160 million years). One distinguishes Gondwana from the Paléozoïque (also called Protogondwana ) and that of the Mesozoic . Between the two, Gondwana belonged to the Supercontinent Pangée. Gondwana was named by Eduard Suess according to the name of an area of the India, Gondwâna, where part of the geology of this old continent could be given.

Protogondwana

During the fracturing of Rodinia (approximately -   750 million years), one distinguishes Eastern Gondwana (Southern Africa, the Eastern Antarctic, Australia, India, Madagascar, Arabia, New Guinea, China of North, China of the South, Indo-China and Bassin of Tarim) and Western Gondwana (Amazonia, Craton of Rio de Plata, Western Africa, Florida, Avalonia and Europe of the South). They enter in collision 600 million years ago while taking tortures of it the Craton of Congo, forming the Panafrican Orogénèse.

For the following period, Ordovicien with the Carboniferous , terranes (fragments of continents) gradually will be detached from Gondwana which is located then around the South pole and will derive towards north: the terrane of Avalonia is detached some towards 490 my, followed by the Armorican and Iberian blocks towards 430 my, the Chinese blocks and Indochinese towards 400 my.

Formation and dislocation of Pangée

At the beginning of the Carboniferous , Gondwana, which has him even slowly derived towards the north, starts its collision with the Supercontinent Laurussia, creating the Orogénèse hercynienne (see Hercynien) which raises the the Appalachian Mountains and Maurétanides: it is the assembly of the Pangée, completed at the beginning of the Permien (290 my). Within the Pangée, Gondwana still loses the terrane Cimmeria, including fragments of current the Turkey, Iran, Afghanistan and Tibet, which derives towards north. Pangée is fractured at the end of the Trias, roughly there or it had been assembled, opening the Atlantique between Gondwana and the Supercontinent Laurasia. Gondwana however loses in the process the Florida and the peninsula of the Yucatan, which will remain welded with Laurasia.

Parcelling out of Gondwana

Gondwana parcels out during the Jurassic superior, 160 million years ago, when a Rift separates Africa from India. 125 million years ago India is entirely detached then New Zealand (80 million years). At the beginning of the Cenozoic the Australian block and the New Guinea separate gradually while moving towards north while swivelling on itself and thus remains connected to Gondwana for one long period.

45 million years ago the India enters in collision with the Asia forcing the earth's crust to fold itself and thus forming the the Himalayas. In same time the southern part of Australia (current the Tasmanie) separates from the Antarctic allowing the creation of oceanic currents between them what produced a colder climate and more dryness.

15 million years ago, the New Guinea enters in collision with the south of Asia and more recently the South America bound to the North America.

Effects on the world climate

From a climatological point of view the separation of South America had an effect much more important. With the opening of the Passage of Drake 23 million years ago, there is no more barrier for the exchange of cool water of the southern ocean and tropical water. A current Circumpolaire is set up and the the Antarctic becomes what it is nowadays: a frozen continent containing most of soft water reserves of the world. The temperature of the sea fell of 10°C and the total climate became much colder.

See too

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