India peeled off from Antarctica, and Africa and South America rifted, according to a 1970 article in the Journal of Geophysical Research. Then about 150 million years ago, Gondwana broke up. Gondwana (what is now Africa, South America, Antarctica, India and Australia) first split from Laurasia (Eurasia and North America). The supercontinent fractured largely along previous sutures. The breakup began about 195 million years ago in the early Jurassic period, when the Central Atlantic Ocean opened, according to the chapter. Pangaea broke up in several phases between 195 million and 170 million years ago. (Image credit: Tinkivinki via Getty Images) The movement of mainlands on the planet Earth in different periods from 225 million years ago to present due to continental drift. Later, during the Permian period (299 million to 251 million years ago), "many former peri-Gondwanan terranes drifted off the north-east Gondwana margin, commencing the opening of the Neotethys Ocean," according to the chapter. For instance, "the Paleotethys Ocean to the east of Pangea remained wide throughout the Carboniferous and presented something of a barrier between the supercontinent and a number of large, independent Asian terranes, including Tarim, North China, South China, and Annamia." "Pangea never included all the continents at any one time," according to the chapter. However, Pangaea wasn't the megalithe most people think it is. Another ocean - called Iapetus, after a mythical Greek titan - between the paleo-continents Laurentia, Baltica and Gondwana, began to close during the Ordovician period (485 million to 444 million years ago) and then disappeared during the Silurian period (444 million to 419 million years ago), when Baltica and Avalonia collided with Laurentia to form Laurussia, according to the chapter, " Phanerozoic paleogeography and Pangea."įinally, about 320 million years ago, there was a major collision, geologically speaking, "when Gondwana, Laurussia, and intervening terranes collided to form the Pangea supercontinent," according to the chapter, written by Earth scientists Trond Torsvik, Mathew Domeier and Robin Cocks. The Northern Hemisphere was largely covered by the Panthalassic Ocean. In the early Phanerozoic eon (541 million years ago to now), almost all of the continents were in the Southern Hemisphere, with Gondwana, the largest continent, spanning from the South Pole to the equator, according to a chapter in the scientific book " Ancient Supercontinents and the Paleogeography of Earth" (Elsevier, 2021). The supercontinent formed through a gradual process spanning a few hundred million years. The word "Pangaea" comes from the Greek "pan," which means "all," and "gaia" or "Earth," according to the Online Etymology Dictionary. (Image credit: Dimitrios Karamitros via Getty Images) The formation of the continents by the separation of Pangaea due to continental drift. And mountain chains that now lie on different continents, such as the Appalachians in the United States and the Atlas Mountains spanning Morocco, Algeria and Tunisia were all part of the Central Pangaea Mountains, formed through the collision of the supercontinents Gondwana and Laurussia. In the fossil record, identical plants, such as the extinct seed fern Glossopteris, are found on now widely disparate continents. And the orientation of magnetic minerals in geologic sediments reveals how Earth's magnetic poles migrated over geologic time, Murphy said. That indicates that North America and Europe must have once been a single landmass. Coal deposits found in Pennsylvania have a similar composition to those spanning across Poland, Great Britain and Germany from the same time period. Another telltale hint that Earth's continents were all one land mass comes from the geologic record. The first and most obvious was that the "continents fit together like a tongue and groove," something that was quite noticeable on any accurate map, Murphy said.
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