Paleocontinent
A paleocontinent or palaeocontinent is a distinct area of continental crust that existed as a major landmass in the geological past.
[citation needed] 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 movement of the continents greatly affects the overall dispersal of organisms throughout the world and the trend in climate throughout Earth's history.
[3] Examples include Laurentia, Baltica and Avalonia, which collided together during the Caledonian orogeny to form the Old Red Sandstone paleocontinent of Laurussia.
Gondwana was located in the southern hemisphere, with the land mass that makes up current day Antarctica closest to the South Pole.
[6] Gondwana was made of present-day South America, Africa, Arabia, India, Antarctica, Australia, and Madagascar.
During the Ordovician, sea levels rose so much that the entire Gondwana continent was covered, at this time marine life was dominant.
[13] Gondwana experienced a variety of climates as it has been a land mass from 600 million years ago in the Precambrian to the Early Jurassic with the breakup of Pangea.
The climate began to change again during the Mesozoic, this time period was dominated by a very large and lengthy monsoon season, because of Pangea.
In the late Proterozoic Laurentia could be found surrounded by Siberia, South Africa, Australia-Antarctica, and Amazonia-Baltica.
The craton itself formed in deep time, the early Proterozoic age of the Earth and has stayed coherent since.
These smaller land masses were made of Archean age crust and belts of Early Proterozoic island arcs.
[11] When Laurentia moved into the Devonian period fish began to diversify and life had begun colonizing land as this is when organic soil accumulation can be detected.
[13] At the end of this new era was a mass extinction of Dinosaurs and reptiles, this led mammals to flourish as they could take over many of the niches that became vacant.
During the Cambrian, there was no ice age and it was slightly warmer as most continents avoided the poles giving land at this time a milder climate.
The climate began to change when Laurentia entered the Mesozoic Era, this time period was dominated by a very large and lengthy monsoon season, because of Pangea.
[14] At the end of the Cretaceous, seasons started to return and the Earth entered another ice age type event.
[19] The continent spanned from 85° N to 90° S. Pangea was centered over the equator, and encompassed area from the North to the South poles.
The Southeastern part of present-day North America and the Northern region of current day Africa intersected the equator.
This recovery included the rise of sea levels which created extensive shallow oceanic shelves for large marine reptiles.
[26] The main characteristic of Pangea's climate is that its position on Earth was advantageous for starting a cycle of megamonsoonal circulation.
During the late Carboniferous, there was peat formation in what is currently Europe and the Eastern areas of North America.
Around the same time parts of current day Australia that were found at higher latitudes were much drier and seasonal in character.
[14] Rodinia was centered on the Equator and reached from 60° N to 60° S.[27] 1.2-1 bya to 800-850 mya, Proterozoic Eon - end of Precambrian.
The shelves were nutrient rich and this is thought to have led to the diversification of vegetative and non-vegetative life on Earth.
The name Rodinia also alludes to this, in Russian it means ‘to give birth’ and in this case that is to animal life here on Earth.
Rodinia already had some glaciation but as it tore apart, less dense rock began to rise causing more land area to be at higher elevations which encouraged more ice to stick.
