Rheic Ocean

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The Rheic Ocean was an ocean in the Paleozoic Era that existed between:

to the north the continent of Baltica (northern Europe) and number of terranes broken off from Gondwana, including Avalonia, the future southern Europe.
to the south the gigantic paleocontinent of Gondwana, or from the Silurian onward the Hunic terranes that broke off Gondwana.

The Rheic Ocean formed in the Late Cambrian-Early Ordovician as a result of the drift of Avalonia, from the northern margin of Gondwana. It all began with a rift, similar to today's East Africa Rift. This rift flow probably came from Proto-Tethys Ocean's mid-ocean ridge. As this microcontinent drifted from Gondwana, a mid-ocean ridge was forming between them, forcing Avalonia to head across the aging Iapetus Ocean, this occurred in the early part of Middle Ordovician. For much of the Late Ordovician, Rheic Ocean appears to have widened as fast as today's East Pacific Rise (at 17 cm/year). When Baltica and Laurentia collided each other in the Latest Ordovician to form the megacontinent of Euramerica, Rheic ocean had already expanded, replacing most of Iapetus Ocean, which has now become a narrow seaway, between Avalonia and Laurentia. The ocean began to close in the Devonian, when the supercontinent of Gondwana drifted towards Euramerica. By Late Devonian, Rheic Ocean became a narrow ocean that sutured between the Gondwana and Euramerica. In the Early Carboniferous (Mississippian), the eastern part of Rheic Ocean had already closed, due to the collision of Eastern United States with Africa. Later, South America collided against southern United States, completely closing the ocean. These collisions created orogenies - the Ouachita-Alleghenian-Variscan orogeny.

[edit] Name

The ocean between Baltica and Laurentia was named for Iapetus, in Greek mythology the father of Atlas, just as the Iapetus Ocean was the predecessor of the Atlantic Ocean. The ocean between Gondwana and Baltica was then named Rheic Ocean for Rhea, sister of Iapetus.