The history of formation of Gondwana Essay
The history of formation of Gondwana, 499 words essay example
Essay Topic: history
their path and opening the of the new PaleoTethys Ocean towardas the south portion. In Devonian Period, the Gondwana itself headed towards Euramerica, causing Rheic Ocean to shrink. In Early Carboniferous, the northwest Africa had touched south eastern coast of Euramerica, creating southern portion of Appalachian Mountains, and Meseta Mountains. The South America moved northward to the southern Euramerica, while eastern portion of the Gondwana (India, Antarctica and Australia) headed towards South Pole from the equator. North and South China were on independent continents. The Kazakhstania microcontinent had collided with the Siberia. (Siberia had been a separate continent for millions of the years since the deformation of supercontinent Pan notia in Middle Carboniferous.)
Western Kazakhstania collided with the Baltica in Late Carboniferous, closing Ural Ocean between them and western ProtoTethys in them (Uralian orogeny), causing formation of not only the Ural Mountains but also supercontinent of the Laurasia. This was last step of formation of the Pangaea. Meanwhile, the South America had collided with the southern Laurentia, closing Rheic Ocean and forming southernmost part of Appalachians and the Ouachita Mountains. By this time, the Gondwana was positioned near South Pole and glaciers were forming in the Antarctica, India, Australia, southern Africa and South America. The North China block collided with the Siberia by the Late Carboniferous time, completely closing ProtoTethys Ocean.
There were three major phases in breakup of the Pangaea. The first phase began in EarlyMiddle Jurassic (about the 175 Ma), when Pangaea began to rift from Tethys Ocean in east to Pacific in west, ultimately giving rise to supercontinents Laurasia and Gondwana. The rifting that took place between North America and the Africa produced the multiple failed rifts. One rift resulted in a new ocean, the North Atlantic Ocean.
The Atlantic Ocean did not open uniformly rifting began in northcentral Atlantic. South Atlantic did not open until Cretaceous when the Laurasia started to rotate clockwise and moved towards northward with the North America to north and Eurasia to the south. The clockwise motion of the Laurasia led much later to closing of Tethys Ocean. Meanwhile, on other side of the Africa and along adjacent margins of the east Africa, Antarctica and Madagascar, new rifts were forming that would lead to formation of southwestern Indian Ocean that would open up in Cretaceous.
Another the important phase occurs of breakup of the Pangaea began in Early Cretaceous (150140 Ma), when minor supercontinent of the Gondwana separated into the multiple continents (Africa, South America, , Antarctica, Australia and india). The subduction at the Tethyan Trench probably caused the Africa, India and Australia to move towards northward, causing opening of the South Indian Ocean. In Early Cretaceous,the Atlantica, today's South America and the Africa, finally separated from eastern Gondwana (Antarctica, India and the Australia). Then in Middle Cretaceous, the Gondwana fragmented to open up South Atlantic Ocean as the South America started to move towards westward away from Africa. The South Atlantic did not develop uniformly rather, it rifted from south to north.