History of the Earth: the supercontinent Pangea

History of the Earth: the supercontinent Pangea

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The supercontinent Pangea existed between the end of the Paleozoic era and early Mesozoic era and it grouped most of the emerged lands of the planet. It was formed approximately 335 million years ago Y began to separate about 175 million years ago, disintegrating until reaching the current situation of the continents.

Origin of the Pangea concept

The first person in baptize this supercontinent as Pangea it was apparently Alfred Wegener, known for being the author of the theory of continental drift in 1912, being the father of the plate tectonics theory.

Pangea comes from the Greek «bread", Which means" everything, "and"gea", Which means" soil "or" land. " Was the most recent supercontinent that has existed, and in turn, the first to be rebuilt by geologists.

In contrast to today's Earth and its continental mass distribution, much of Pangea was in the southern hemisphere, being surrounded by the super ocean Panthalassa.

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Formation of supercontinents on Earth

The formation and rupture of supercontinents appears to have been cyclical throughout the history of the earth. In fact, it is believed that there have been many before Pangea and they would be the following:

  • Vaalbara (hypothetical)
  • Ur (hypothetical)
  • Kenorland
  • Columbia
  • Rodinia
  • Pannotia
  • Pangea

The formation of the supercontinent Pangea

First step of the formation of Pangea

At Cambrian period, the continent of Laurentia, which would later become North America, settled in the Equator with three bordering oceans: the Panthalassa Ocean to the north and west, the Iapetus Ocean to the south, and the Janty Ocean to the east.

In the oldest Ordovician period, the second of the Paleozoic or Primary era (which follows the Cambrian and precedes the Silurian) between 500 and 430 million years ago, the microcontinent of Avalonia, a landmass incorporating fragments of what later would become eastern Newfoundland, the southern British Isles, and parts of Belgium, France, Nova Scotia, New England, southern Iberia, and northwestern Africa, broke free from Gondwana and began its journey to Laurentia.

Baltic, Laurentia and Avalonia, meanwhile, joined at the end of the Ordovician to form a minor supercontinent called Euramérica or Laurusia, closing the ocean of Iapetus. This collision also resulted in the formation of the northern Appalachians.

Siberia, for its part, settled near Euramérica, having the Janty Ocean separating the two land.

While all this was happening, Gondwana slowly moved towards the South Pole.

All these movements were the first step in the formation of Pangea.

Second step of the formation of Pangea

The second step in the formation of Pangea was the collision of Gondwana with Euramérica. In the Silurian era, 440 million years ago, Baltic had already collided with Laurentia forming Euramérica.

Avalonia had not yet collided with Laurentia, but as Avalonia advanced towards Laurentia, the dirt road between them, a remnant of the Iapetus ocean, was slowly shrinking.

Meanwhile, southern Europe broke away from Gondwana and began moving toward Euramerica through the newly formed Rheic Ocean.

For its part, the sister ocean of Iapetus, that of Janty, was reduced when an insular arc of Siberia collided with eastern Baltic (now part of Euramerica), and behind this island arc a new ocean was born, the Ural.

Third step of the formation of Pangea

In the late Silurian, northern and southern China parted ways with Gondwana and began heading north, shrinking the Proto-Tethys ocean in its path, and opening up the new Paleo-Tethys ocean in the south.

At Devonian period, Gondwana headed towards Euramerica, causing the Reico Ocean to decrease in size.

In the early Carboniferous periodNorthwest Africa had touched the southeastern coast of Euramérica, creating the southern portion of the Appalachians and other mountains such as the Mauritanians.

South America moved north to southern Euramerica, while the eastern part of Gondwana (India, Antarctica, and Australia), headed toward the South Pole from the Equator.

North and South China were on separate continents, while the Kazakhstan microcontinent had collided with Siberia, the latter being a separate continent for millions of years since the partition of the supercontinent Pannotia.

In the late Carboniferous, western Kazakhstan collided with the Baltic, closing the Ural Ocean between them, and the western Proto-Tethys in them (Uralian orogeny), causing not only the formation of the Ural Mountains, but also that of the supercontinent of Laurasia.

This was the last step of the formation of Pangea.

Meanwhile, South America had collided with southern Laurentia, closing off the Reico Ocean and forming the southernmost part of the Appalachians and the Ouachita Mountains.

At the time, Gondwana was near the South Pole and glaciers were forming in Antarctica, India, Australia, southern Africa, and South America.

The northern block of China collided with Siberia in the late Carboniferous, completely closing off the Proto-Tethys ocean.

Final formation of Pangea

At the beginning of the Permian period, the continent of Cimmeria separated from Gondwana and headed towards Laurasia, thus closing the Paleo-Tethys ocean, but forming a new one, the Ocean Tethys.

This is when most continental masses on Earth they formed all, a single supercontinent

The separation of the supercontinent Pangea

We can separate Pangea divide into three phases well delimited:

First phase

The first of them began in the period Early-Middle Jurassic (175 million years ago), when Pangea began to separate from the Tethys Ocean in the east, to the Pacific in the west.

This rift separated North America from Africa and also resulted in the creation of a new ocean, the North Atlantic Ocean.

For his part the South Atlantic Ocean It did not open until the Cretaceous, when Laurasia began to rotate clockwise and moved north with North America, and south with Eurasia.

This continuous movement of Laurasia led to the closure of the Tethys Ocean and the appearance of the Arctic Ocean.

Meanwhile, along the margins of Africa, Antarctica and Madagascar, new divisions were occurring that would lead to the formation of the Indian Ocean.

Second stage

The second phase of the breakup of Pangea started in the Lower Cretaceous (150-140 million years ago), when Gondwana spread into the continents of Africa, South America, India, Antarctica, and Australia.

In the Middle Cretaceous, Gondwana fragmented opening up the South Atlantic Ocean, as South America began to move west, away from Africa.

In this period is when India began to move north towards Eurasia, while New Zealand, New Caledonia and the rest of Zealand began to separate from Australia, moving east towards the Pacific, opening the Coral Sea and the Tasman Sea.

Third phase

The third and final phase of the Pangea breakup it happened to early Cenozoic, when Laurasia separated at the time when North America and Greenland (called Laurentia) in turn separated from Eurasia by opening up the Norwegian Sea.

Meanwhile, the Atlantic and Indian Oceans continued to expand (definitively closing the Tethys Ocean), Australia separated from Antarctica and began to move rapidly north, just as India had done before.

In fact, Australia is currently on a collision course with East Asia, and India continues to move north into the rest of the continent. This collision is what allowed the creation of the Himalayan chain.

Antarctica has been near or at the South Pole since the formation of Pangea.

The African plate began to change direction, from west to northwest towards Europe, and South America began to move in a northward direction, separating from Antarctica and allowing full ocean circulation around Antarctica.

This movement, together with the decrease of carbon dioxide in the atmosphere, caused a rapid cooling of Antarctica and allowed the formation of glaciers, reaching what we know today.

Other major geological events occurred during the Cenozoic, such as the opening of the Gulf of California, the rising of the alps and the opening of the Sea of ​​Japan.

Pangea breakout continues today in the Red Sea and in East Africa.

Plate tectonics

The pangea formation is commonly explained with plate tectonics created by Alfred Wegener and with it you can also explain whyPangea did not part in one gobut has done so sequentially at different times.

Furthermore, after these separations, it has been found that land masses also continue to break down.

In turn, it has been shown that the formation of each environment and climate in Pangea is due precisely to plate tectonics, and as a result of these changes, different climates existed on the supercontinent.

They have also made it possible to observe the formations of the plates themselves. Thus, mountains and valleys are formed due to tectonic collisions, as do earthquakes. In addition, it can contribute to volcanic activity which has been responsible for extinctions and adaptations of life throughout time on Earth.

Life on the supercontinent Pangea

During the 160 million years of existence of Pangeamany species have arisen on Earth, both marine and terrestrial, such as Traversodontidae (family of herbivores), great variety of plants and insects.

However, 252 million years ago the so-called Permian-Triassic mass extinction, causing the loss of more than 90% of marine species, and 70% of terrestrial species, also being the only extinction that affected insects.

Video: History of the Earth