Columbia (supercontinent)
Columbia is in the Earth's history, the name of a hypothetical Paleoproterozoic supercontinent, is said to have existed before 1800 to about 1600 million years ago ( about the same time the Statherium ). He is said to have almost all the major continental fragments which then existed on Earth combined.
Naming
The term was coined by John JW Rogers and M. Santosh in a work from the year 2002. Enter as Derivatio nominis that the name should allude to the key link between India and the Columbia region in the U.S. state of Washington.
Columbia as a geological continent
Columbia was built 2100-1800 million years ago. It contained almost all of the major continental blocks that existed at the earth. According to Rogers and Santosh (2002), the east coast of India today touched the western North America. The southern Australia was still north of the western Canada. The largest part of South America was so moved that the western edge of the present-day Brazil abutted the eastern North America and handed to Scandinavia. According to reconstruct them to Columbia was formed by the collision of three previously incurred major continents Arctica (North America, Siberia, Greenland, Baltica ), Atlantica (eastern South America and western Africa) and a block consisting of parts of Australia, India, Madagascar, South Africa and parts of Antarctica. The exact position of the cratons to each other, however, is highly controversial. To reconstruct Zhao et al. (2004 ) Columbia completely different. In their reconstruction Antarctica is located southwest of North America, north of Australia, and then some smaller blocks. West of Antarctica still followed India and North China. North of North America, Siberia, Greenland and east joined them to Baltica. Atlantica lay south of Baltica, separated from the eastern edge of North America by a larger sea area.
Following the " Pangaea " situation took place at the edges of 1800-1300 millions of years lasting subduction and accretion. Thus was formed 1800-1300 million years ago, a broad magmatic Akkretionsgürtel along the southern edge of present-day North America, Greenland and the nucleus of the later Baltica. In South America, there is a 1800 to 1300 million years old Akkretionszone along the western margin of the Amazonia Craton. In Australia, from 1800 to 1500 million year old igneous belt surrounds the southern and eastern edge of the North Australian craton and the eastern edge of the Gawler Craton. In China extends a 1800-1400 million year old akkretionärer magmatic belt along the southern margin of the North China Craton. The disintegration of the supercontinent Columbia began around 1600 million years ago, with continental rifting at the western edge of Laurentia, the southern edge of Baltica, the southeastern edge of Sibiria the north-western border of South Africa and the northern edge of North China. The breaking and the fragmentation of the supercontinent coincides with a widespread magmatic activity that anorthosite Mangerit - Charnockite Granite ( AMCG ) suites formed in North America, Baltica, Amazonia and northern China. The magmatic activity lasted until the final disintegration of Columbia to 1300-1200 million years ago when the mafic MacKenzie and Sudbury transition swarms formed.
The existence of a supercontinent Columbia is believed primarily due to approximate global magmatic events in the period from 2100 to 1300 million years ago. The north - south expansion is assumed to be 12,900 kilometers, with 4,800 kilometers at the widest point.
In the recent literature of the originally defined differently geological continent Nuna is equated with Columbia.