Supercontinent

From Palaeos

A supercontinent is any landmass that contains 2 or more cratons, or "continental cores." Eurasia is the best known modern-day example of a supercontinent.

The earliest known supercontinent was Vaalbara. It formed from proto-continents and was a supercontinent by 3.1 billion years ago (3.1 Ga). Vaalbara broke up ~2.8 Ga. The supercontinent Kenorland was formed ~2.7 Ga and then broke sometime after 2.5 Ga into the proto-continent cratons called Laurentia, Baltica, Australia and Kalahari. The supercontinent Columbia formed and broke up during a period of 1.8 to 1.5 Ga.

The supercontinent Rodinia broke up roughly 750 million years ago. One of the fragments included large parts of the continents now located in the southern hemisphere. Plate tectonics brought the fragments of Rodinia back together in a different configuration during the late Paleozoic era, forming the best-known supercontinent, Pangaea. Pangaea subsequently broke up into the northern and southern supercontinents, Laurasia and Gondwana.

Modern studies have suggested that supercontinents form in cycles, coming together and breaking apart again through plate tectonics, very roughly about every 250 million years.

[edit] Geology

Supercontinents block the flow of heat from the Earth's interior, and thus cause the asthenosphere to overheat. Eventually, the lithosphere will begin to dome upward and crack, magma will then rise, and the fragments will be pushed apart. A modern example of this process can be seen in the Rift Valley of east Africa.

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