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Paleocontinent


A paleocontinent or palaeocontinent is a distinct area of continental crust that existed as a major landmass in the geological past. There have been many different landmasses throughout Earth’s time. They range in sizes, some are just a collection of small microcontinents while others are large conglomerates of crust. As time progresses and sea levels rise and fall more crust can be exposed making way for larger landmasses. The continents of the past shaped the evolution of organisms on Earth and contributed to the climate of the globe as well. As land masses break apart species are separated and that were once the same now have evolved to their new climate. The constant movement of these landmasses greatly determines the distribution of organisms on the Earth’s surface. This is evident with how similar fossils are found on completely separate continents. Also, as continents move, mountain building events (orogenies) occur, causing a shift in the global climate as new rock is exposed and then there is more exposed rock at higher elevations. This causes glacial ice expansion and an overall cooler global climate. Which effects the overall global climate trend of the Earth. The movement of the continents greatly affects the overall dispersal of organisms throughout the world and the trend in climate throughout the Earth’s history. Examples include Laurentia, Baltica and Avalonia, which collided together during the Caledonian orogeny to form the Old Red Sandstone paleocontinent of Laurussia. Another example includes a collision that occurred during the late Pennsylvanian and early Permian time when there was a collision between the two continents of Tarimsky and Kirghiz-Kazakh. This collision was caused because of their askew convergence when the paleoceanic basin closed.

The examples below are condensed in order to portray a brief overview of several paleocontinents.

Rodinia was centered on the equator and reached from 60° N to 60° S.

1.2-1 bya to 800-850 mya, Proterozoic Eon - end of Precambrian.

It was the first supercontinent to form on Earth, all the continental crust on Earth came together and formed one giant land mass. This land mass was surrounded by an even larger ocean, known as Mirovia. There were about four smaller continents that collided and came together to form Rodinia. This event is called the Grenville Orogeny. This caused there to be mountain building along the areas of were continents collided. This is because the continental crust is not very dense so neither continent would sink or sub duct. This causes the formation of Fold and Thrust belts, similar to the Himalayas today. 


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