Plate tectonics is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s. The processes that result in plates and shape Earth's crust are called tectonics. Tectonic plates also occur in other planets and moons.
In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leaves room for interpretation and is easier to apply to Precambrian times. To separate supercontinents from other groupings, a limit has been proposed in which a continent must include at least about 75% of the continental crust then in existence in order to qualify as a supercontinent.
Laurasia was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago (Mya), the other being Gondwana. It separated from Gondwana 215 to 175 Mya during the breakup of Pangaea, drifting farther north after the split and finally broke apart with the opening of the North Atlantic Ocean c. 56 Mya. The name is a portmanteau of Laurentia and Asia.
The Mid-Atlantic Ridge is a mid-ocean ridge located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world. In the North Atlantic, the ridge separates the North American from the Eurasian plate and the African plate, north and south of the Azores Triple Junction. In the South Atlantic, it separates the African and South American plates. The ridge extends from a junction with the Gakkel Ridge northeast of Greenland southward to the Bouvet Triple Junction in the South Atlantic. Although the Mid-Atlantic Ridge is mostly an underwater feature, portions of it have enough elevation to extend above sea level, for example in Iceland. The ridge has an average spreading rate of about 2.5 centimetres (1 in) per year.
Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean, was the vast superocean that encompassed planet Earth and surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth. During the Paleozoic–Mesozoic transition, the ocean occupied almost 70% of Earth's surface, with the supercontinent Pangaea taking up less than half. The original, ancient ocean floor has now completely disappeared because of the continuous subduction along the continental margins on its circumference. Panthalassa is also referred to as the Paleo-Pacific or Proto-Pacific because the Pacific Ocean is a direct continuation of Panthalassa.
Pangaea Proxima is a possible future supercontinent configuration. Consistent with the supercontinent cycle, Pangaea Proxima could form within the next 250 million years. This potential configuration, hypothesized by Christopher Scotese in November 1982, earned its name from its similarity to the previous Pangaea supercontinent. Scotese later changed Pangaea Ultima to Pangaea Proxima to alleviate confusion about the name Pangaea Ultima which could imply that it would be the last supercontinent. The concept was suggested by extrapolating past cycles of formation and breakup of supercontinents, not on theoretical understanding of the mechanisms of tectonic change, which are too imprecise to project that far into the future. "It's all pretty much fantasy to start with," Scotese has said. "But it's a fun exercise to think about what might happen. And you can only do it if you have a really clear idea of why things happen in the first place."
In hydrology, an oceanic basin (or ocean basin) is anywhere on Earth that is covered by seawater. Geologically, most of the ocean basins are large geologic basins that are below sea level.
The supercontinent cycle is the quasi-periodic aggregation and dispersal of Earth's continental crust. There are varying opinions as to whether the amount of continental crust is increasing, decreasing, or staying about the same, but it is agreed that the Earth's crust is constantly being reconfigured. One complete supercontinent cycle is said to take 300 to 500 million years. Continental collision makes fewer and larger continents while rifting makes more and smaller continents.
A superocean is an ocean that surrounds a supercontinent. It is less commonly defined as any ocean larger than the current Pacific Ocean. Named global superoceans include Mirovia, which surrounded the supercontinent Rodinia, and Panthalassa, which surrounded the supercontinent Pangaea. Pannotia and Columbia, along with landmasses before Columbia, were also surrounded by superoceans.
Christopher R. Scotese is an American geologist and paleogeographer. He received his PhD from the University of Chicago in 1985. He is the creator of the Paleomap Project, which aims to map Earth over the last billion years, and is credited with predicting Pangaea Ultima, a possible future supercontinent configuration. Later Scotese changed Pangaea Ultima to Pangaea Proxima to alleviate confusion about the name Pangaea Ultima, which would imply that it would be the last supercontinent.
The geological history of the Earth follows the major geological events in Earth's past based on the geological time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System.
Afro-Eurasia is a landmass comprising the continents of Africa, Europe, and Asia. The terms are compound words of the names of its constituent parts. Afro-Eurasia has also been called the "Old World", in contrast to the "New World" referring to the Americas.
Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million years ago, and began to break apart about 200 million years ago, at the end of the Triassic and beginning of the Jurassic. Pangaea was C-shaped, with the bulk of its mass stretching between Earth's northern and southern polar regions and surrounded by the superocean Panthalassa and the Paleo-Tethys and subsequent Tethys Oceans. Pangaea is the most recent supercontinent to have existed and the first to be reconstructed by geologists.
This is a list of articles related to plate tectonics and tectonic plates.
The biological and geological future of Earth can be extrapolated based on the estimated effects of several long-term influences. These include the chemistry at Earth's surface, the cooling rate of the planet's interior, the gravitational interactions with other objects in the Solar System, and a steady increase in the Sun's luminosity. An uncertain factor is the pervasive influence of technology introduced by humans, such as climate engineering, which could cause significant changes to the planet. For example, the current Holocene extinction is being caused by technology, and the effects may last for up to five million years. In turn, technology may result in the extinction of humanity, leaving the planet to gradually return to a slower evolutionary pace resulting solely from long-term natural processes.
Novopangaea or Novopangea is a possible future supercontinent postulated by Roy Livermore in the late 1990s. It assumes closure of the Pacific, docking of Australia with East Asia and North America, and northward motion of Antarctica.
The opening of the North Atlantic Ocean is a geological event that has occurred over millions of years, during which the supercontinent Pangea broke up. As modern-day Europe and North America separated during the final breakup of Pangea in the early Cenozoic Era, they formed the North Atlantic Ocean. Geologists believe the breakup occurred either due to primary processes of the Iceland plume or secondary processes of lithospheric extension from plate tectonics.
Aurica is a possible future supercontinent configuration. It is one of the four proposed supercontinents that are speculated to form within 200 million years, the others being Pangaea Proxima, Amasia, and Novopangaea. The Aurica hypothesis was created by scholars at the Geological Magazine following an American Geophysical Union study linking the strength of ocean tides to the supercontinent cycle. The name is a portmanteau of America and Australia, which form the core of the supercontinent. The study noted that "When tectonic plates slide, sink and shift the Earth's continents to form large landmasses, or supercontinents, ocean basins open and close in tandem. As these basins change shape, they can strike forms that amplify and intensify their tides."
A continent is a large geographical region defined by the continental shelves and the cultures on the continent. In the modern day, there are seven continents. However, there have been more continents throughout history. Vaalbara was the first supercontinent. Europe is the newest continent. Geologists have predicted that certain continents will appear, these being Pangaea Proxima, Novopangaea, Aurica, and Amasia.
