Rodinia

Rodinia was a hypothetical supercontinent in the Proterozoic. He is said to have originated 1.1 billion years ago and initially broken before about 800 million years ago into two large fragments. Rodinia was surrounded by a single ocean, Mirovia.

The name comes from the Russian word for родина "homeland" or " родить " for " bear ", because in Rodinia, the cores of all subsequent continents were united. It was coined in 1990 by Marc McMenamin and Dianna Schulte McMenamin.

The existence of a supercontinent in the Neoproterozoic is hardly more controversial in the research. However, there are two fundamentally different concepts, the concept of Rodinia and the Palaeopangaea concept by John Piper. The Rodinia concept is currently favored in the literature. The position of the continents within Rodinias and the chronology, however, are still controversial.

Arrangement of land masses

The model of a supercontinent Rodinia is based on a continent configuration in which Laurentia formed the center around which clustered the other continents. On the other hand is completely different Palaeopangaea the model of John D. Piper, emanating from the Pangaea -like arrangement of the continents. Meanwhile also the Rodinia model has differentiated into several variants, referred to in the literature as SWEAT, AUSWUS and AUSMEX.

The SWEAT variant ( from Southwest U.S. - East Antarctica ) assumes that Antarctica southwest joined to Laurentia. Australia was then north to Antarctica.

The AUSWUS variant (of Australia - western U.S.) is, however, believe that Australia at that time was on the western edge of Laurentia. Antarctica was in the same position in Australia as in the SWEAT- variant, however, had by the more southern position of Australia no direct contact with Laurentia.

In the AUSMEX variant ( of Australia - Mexico) Australia is even further south of Laurentia (relative to the current situation in North America ) and closed at approximately the level of Mexico to Laurentia at.

Bogdanova et al. (2009 ), based on Li et al. (2008) rejects all three variants. Both works are based on a Rodinia configuration, lay on the west coast Laurentias in south China. Parts of South America joined on the east coast Laurentias, north of it followed Baltica. South Laurentias were different blocks of the later Gondwana, north Laurentias lay Greenland and Siberia. The positions refer to about the orientation of present-day North America. In contrast, Goodge et al emphasize. (2008) again, the SWEAT model. It will be still a long way to go before the research into a matching model of a supercontinent Rodinia comes.

Rodinia as a geological continent

Rodinia was formed by orogenic processes in the period 1300-900 million years ago, mainly by the large-scale Grenville orogeny. Before about 900 million years ago were probably all continental blocks that existed at that time, combined to form a supercontinent. Rodinia remained as super-continent for about 150 million years before it fell into two large blocks ( Nordrodinia and Südrodinia ). Between 825 and 740 million years ago continental rifting was widespread. The cause was probably a Superplume under Rodinia, what can be episodic plume events at 825, 780 and 750 million years ago close. In the upper Precambrian ( 650-550 million years ago) collided with the three Neoproterozoic continents Nordrodinia, Südrodinia and the Congo craton during the Cadomian orogeny and formed the second Neoproterozoic supercontinent, Pannotia ( "Greater Gondwana ").

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