Pangaea Proxima

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A rough approximation of Pangaea Proxima according to the early model on the Paleomap Project website. The central sea is the "Medi-Pangaean Sea". The newer model has Australia and Antarctica between South America and southeast Asia, south of the Medi-Pangaean Sea. PangeaUltimaRoughEstimation.png
A rough approximation of Pangaea Proxima according to the early model on the Paleomap Project website. The central sea is the "Medi-Pangaean Sea". The newer model has Australia and Antarctica between South America and southeast Asia, south of the Medi-Pangaean Sea.

Pangaea Proxima (also called Pangaea Ultima, Neopangaea, and Pangaea II) 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 (Last Pangaea) to Pangaea Proxima (Next Pangaea) to alleviate confusion about the name Pangaea Ultima which could imply that it would be the last supercontinent. [1] 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." [2]

Contents

Supercontinents describe the merger of all, or nearly all, of Earth's landmass into a single contiguous continent. In the Pangaea Proxima scenario, subduction at the western Atlantic, east of the Americas, leads to the subduction of the Atlantic mid-ocean ridge followed by subduction destroying the Atlantic and Indian basin, causing the Atlantic and Indian Oceans to close, bringing the Americas back together with Africa and Europe. As with most supercontinents, the interior areas of Pangaea Proxima are presumed to become humid, semi-arid deserts that will be prone to extreme temperatures up to 55°C. [3] Most land mammals, including humans, are speculated to be driven to extinction (comparable to the Permian–Triassic extinction event) because of these environments. [4]

Formation

According to the Pangaea Proxima hypothesis, the Atlantic and Indian Oceans will continue to get wider until new subduction zones bring the continents back together, forming a future Pangaea. Most continents and microcontinents are predicted to collide with Eurasia, just as they did when most continents collided with Laurentia. [5]

In the next 50 million years (assuming no new subduction zones come into being before then), North America is predicted to shift west and Eurasia east, and possibly even to the south, bringing Great Britain closer to the North Pole and Siberia southward towards warm, subtropical latitudes. Africa is predicted to collide with Europe and Arabia, closing the Mediterranean Sea (thus completely closing the Tethys Ocean (or Neotethys)) and the Red Sea between Sudan and Saudi Arabia. A long mountain range (the Mediterranean Mountain Range) would then extend from Iberia, across Southern Europe and into Asia. Some are even predicted to have peaks higher than Mount Everest between Spain, Greece, Italy, and Egypt. Similarly, Australia is predicted to beach itself past the doorstep of Southeast Asia, causing islands such as the Philippines and Indonesia to be compressed inland, forming another potential mountain range while Japan will collide with China, Korea, and Russia. Meanwhile, Southern and Baja California are predicted to have already collided with Alaska with new mountain ranges formed between the United States and Canada. [6]

About 125 million years from now, the Atlantic Ocean is predicted to stop widening and begin to shrink as the Mid-Atlantic Ridge seafloor spreading gives way to subduction. In this scenario, the mid-ocean ridge between South America and Africa will probably be subducted first; the Atlantic Ocean is predicted to narrow as a result of subduction beneath the Americas. The Indian Ocean is also predicted to be smaller due to northward subduction of oceanic crust into the Central Indian trench. Antarctica is expected to split in two and shift northwards, colliding with Madagascar and Australia, enclosing a remnant of the Indian Ocean, which Scotese calls the "Medi-Pangaean Sea". [7] [8]

When the last of the Mid-Atlantic Ridge is subducted beneath the Americas, the Atlantic Ocean is predicted to close rapidly. [9] Research by Duarte et al in 2024 is consistent with this, noting that the Gibraltar Arc may evolve into a subduction zone entering the Atlantic Ocean and forming an Atlantic analogue to the current Ring of Fire, leading to the closure of the Atlantic Ocean. [10]

At 250 million years in the future, the Atlantic is predicted to have closed, with only small vestiges of the former ocean remaining. North America will have collided with Africa, but be in a more southerly position than where it rifted away. South America is predicted to be wrapped around the southern tip of Africa and Antarctica, completely enclosing the Medi-Pangaean Sea, which will become a supertoxic inland sea that begins to poison the surrounding oceans, lands and atmosphere, leading to another great extinction event. [7] The supercontinent will be encircled by a global ocean, the Neopanthalassan Ocean (meaning "new" Panthalassan Ocean), [7] which encircles half the Earth. [9] The Earth is expected to have a hothouse climate with an average global temperature of 28 °C (82 °F). [7] The only areas likely to be habitable for land mammals are those closest to the poles. [4]

Effects

The formation of Pangaea Proxima will probably dramatically affect the environment. The collision of plates will result in mountain building, thereby shifting weather patterns. The sea level may drop because of increased glaciation. The rate of surface weathering may rise, increasing the rate at which organic material is buried. Pangaea Proxima also has the potential to lower global temperatures and increase atmospheric oxygen. This, in turn, can affect the climate, further lowering global temperatures. [11] These changes as described above can result in more rapid biological evolution as new niches emerge. It has been suggested that the rise in pCO2 and the increased continentality that would accompany the assembly of Pangaea Proxima will result in climatic extremes intense enough to bring about the mass extinction of mammals. [12]

Pangaea Proxima could also insulate the mantle. The flow of heat will be concentrated, resulting in volcanism and the flooding of large areas with basalt. Rifts will form and Pangaea Proxima will split up once more in 400 to 500 million years. Earth may thereafter experience a warming period as occurred during the Cretaceous period, which marked the split-up of the previous Pangaea supercontinent. [13]

Models

There are two models for the formation of Pangaea Proxima — an early model and the current model. The two models differ in where they place Australia, Antarctica, and Chukotka.

The early model, created in 1982 and shown on the Paleomap Project website, places Australia and Antarctica connected to each other as a separate landmass to Pangaea Proxima, close to the South Pole, and Chukotka staying with Eurasia.

The current model, created in 2001 and shown on Christopher Scotese's YouTube channel, [14] has Australia attached to China, East Antarctica attached to South America, and West Antarctica attached to Australia, with Chukotka and the Kamchatka Peninsula attached to North America (Chukotka is on the North American plate; while the Kamchatka Peninsula could either lie on the North American plate or be part of a separate Okhotsk microplate).

Other suggested future supercontinents

Paleogeologist Ronald Blakey has described predictions of the next 15 to 85 million years of tectonic development as fairly settled, without supercontinent formation. [15] Beyond that, he cautions that the geologic record is full of unexpected shifts in tectonic activity driven by currents deep in the Earth's mantle which are largely undetectable and poorly understood, making longer projections "very, very speculative". [15] In addition to Pangaea Proxima, two other hypothetical supercontinents—"Amasia" and "Novopangaea"—were illustrated in an October 2007 New Scientist article. [1] Another supercontinent, Aurica, has been suggested in an article published in 2016. [16]

Research from Curtin University in Australia and Peking University in China published in 2022 supports an Amasia scenario within 200 to 300 million years. The study in the National Science Review suggests that the Pacific Ocean, shrinking since the time of the dinosaurs, may continue until it has closed entirely, resulting in the collision of the Americas with Eurasia. [17]

See also

Related Research Articles

The Mesozoic Era is the era of Earth's geological history, lasting from about 252 to 66 million years ago, comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of gymnosperms and of archosaurian reptiles, such as the dinosaurs; a hot greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic.

<span class="mw-page-title-main">Supercontinent</span> Landmass comprising more than one continental core, or craton

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.

<span class="mw-page-title-main">Laurasia</span> Northern landmass that formed part of the Pangaea 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.

<span class="mw-page-title-main">Iapetus Ocean</span> Ocean that existed in the late Neoproterozoic and early Paleozoic eras

The Iapetus Ocean existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale. It was in the southern hemisphere, between the paleocontinents of Laurentia, Baltica and Avalonia. The ocean disappeared with the Acadian, Caledonian and Taconic orogenies, when these three continents joined to form one big landmass called Euramerica. The "southern" Iapetus Ocean has been proposed to have closed with the Famatinian and Taconic orogenies, meaning a collision between Western Gondwana and Laurentia.

<span class="mw-page-title-main">Arctica</span> Ancient continent in the Neoarchean era

Arctica, or Arctida is a hypothetical ancient continent which formed approximately 2.565 billion years ago in the Neoarchean era. It was made of Archaean cratons, including the Siberian Craton, with its Anabar/Aldan shields in Siberia, and the Slave, Wyoming, Superior, and North Atlantic cratons in North America. Arctica was named by Rogers 1996 because the Arctic Ocean formed by the separation of the North American and Siberian cratons. Russian geologists writing in English call the continent "Arctida" since it was given that name in 1987, alternatively the Hyperborean craton, in reference to the hyperboreans in Greek mythology.

<span class="mw-page-title-main">Pannotia</span> Hypothesized Neoproterozoic supercontinent

Pannotia, also known as the Vendian supercontinent, Greater Gondwana, and the Pan-African supercontinent, was a relatively short-lived Neoproterozoic supercontinent that formed at the end of the Precambrian during the Pan-African orogeny, during the Cryogenian period and broke apart 560 Ma with the opening of the Iapetus Ocean, in the late Ediacaran and early Cambrian. Pannotia formed when Laurentia was located adjacent to the two major South American cratons, Amazonia and Río de la Plata. The opening of the Iapetus Ocean separated Laurentia from Baltica, Amazonia, and Río de la Plata. A 2022 paper argues that Pannotia never fully existed, reinterpreting the geochronological evidence: "the supposed landmass had begun to break up well before it was fully assembled". However, the assembly of the next supercontinent Pangaea is well established.

<span class="mw-page-title-main">Amasia (supercontinent)</span> Possible future supercontinent

Amasia is a possible future supercontinent which could be formed by the merge of Asia and the Americas. The prediction relies mostly on the fact that the Pacific Plate is already subducting under Eurasia and the Americas, a process which if continued will eventually cause the Pacific to close. Meanwhile, because of the Atlantic mid-ocean ridge, North America would be pushed westward. Thus, the Atlantic at some point in the future would be larger than the Pacific. In Siberia, the boundary between the Eurasian and North /South American Plates has been stationary for millions of years. The combination of these factors would cause the Americas to be combined with Asia, thus forming a supercontinent. A February 2012 study predicts Amasia will form over the North Pole, in about 50 to 200 million years, closing the Arctic Ocean.

<span class="mw-page-title-main">Supercontinent cycle</span> Repeated joining and separation of Earths continents

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.

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.

<span class="mw-page-title-main">Paleo-Tethys Ocean</span> Ocean on the margin of Gondwana between the Middle Cambrian and Late Triassic

The Paleo-Tethys or Palaeo-Tethys Ocean was an ocean located along the northern margin of the paleocontinent Gondwana that started to open during the Middle Cambrian, grew throughout the Paleozoic, and finally closed during the Late Triassic; existing for about 400 million years.

<span class="mw-page-title-main">Geological history of Earth</span> The sequence of major geological events in Earths past

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.

<span class="mw-page-title-main">Gondwana</span> Neoproterozoic to Cretaceous landmass

Gondwana was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the Indian Subcontinent.

<span class="mw-page-title-main">Afro-Eurasia</span> Landmass consisting of Africa, Asia, and Europe

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.

<span class="mw-page-title-main">Laurentia</span> Craton forming the geological core of North America

Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and the Hebridean Terrane in northwest Scotland. During other times in its past, Laurentia has been part of larger continents and supercontinents and consists of many smaller terranes assembled on a network of early Proterozoic orogenic belts. Small microcontinents and oceanic islands collided with and sutured onto the ever-growing Laurentia, and together formed the stable Precambrian craton seen today.

<span class="mw-page-title-main">Pangaea</span> Supercontinent from the late Paleozoic to early Mesozoic eras

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.

<span class="mw-page-title-main">Future of Earth</span> Long-term extrapolated geological and biological changes of planet Earth

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.

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 landmasses break apart, species are separated and those 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 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. The movement of the continents greatly affects the overall dispersal of organisms throughout the world and the trend in climate throughout 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.

<span class="mw-page-title-main">Novopangaea</span> Possible future supercontinent

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.

<span class="mw-page-title-main">Aurica (supercontinent)</span> Possible future supercontinent

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."

References

  1. 1 2 Williams, Caroline; Nield, Ted (20 October 2007). "Earth's next supercontinent". New Scientist. 196 (2626): 36–40. doi:10.1016/S0262-4079(07)62661-X. Archived from the original on 13 April 2008. Retrieved 4 August 2016.
  2. ↑ "Continents in collision: Pangaea Ultima". NASA Science News. 6 October 2000. Archived from the original on 9 June 2023. Retrieved 1 October 2023.
  3. ↑ Kargel, Jeffrey S. (2004). "New World". Mars: a warmer, wetter planet . Springer. ISBN   978-1-85233-568-7.
  4. 1 2 Farnsworth, Alexander; Lo, Y. T. Eunice; Valdes, Paul J.; Buzan, Jonathan R.; Mills, Benjamin J. W.; Merdith, Andrew S.; Scotese, Christopher R.; Wakeford, Hannah R. (October 2023). "Climate extremes likely to drive land mammal extinction during next supercontinent assembly". Nature Geoscience. 16 (10): 901–908. Bibcode:2023NatGe..16..901F. doi: 10.1038/s41561-023-01259-3 .
  5. ↑ Broad, William J. (9 January 2007). "Long-Term Global Forecast? Fewer Continents". The New York Times.
  6. ↑ "Our globe in next 50 million years". Volcano World. Oregon State University. Archived from the original on 5 April 2009.
  7. 1 2 3 4 Scotese, Christopher R. (30 May 2021). "An Atlas of Phanerozoic Paleogeographic Maps: The Seas Come In and the Seas Go Out". Annual Review of Earth and Planetary Sciences. 49 (1): 679–728. Bibcode:2021AREPS..49..679S. doi: 10.1146/annurev-earth-081320-064052 . S2CID   233708826.
  8. ↑ Scotese, Christopher R (2 February 2003). "The Atlantic Ocean begins to Close". Paleomap Project. Retrieved 24 March 2012.
  9. 1 2 Scotese, Christopher R (2 February 2003). "'Pangea Ultima' will form 250 million years in the Future". Paleomap Project. Retrieved 13 March 2006.
  10. ↑ Duarte, João C.; Riel, Nicolas; Rosas, Filipe M.; Popov, Anton; Schuler, Christian; Kaus, Boris J.P. (2024). "Gibraltar subduction zone is invading the Atlantic". Geology. doi:10.1130/G51654.1 . Retrieved 10 April 2024.
  11. ↑ Young, Grant M. (1 May 2013). "Precambrian supercontinents, glaciations, atmospheric oxygenation, metazoan evolution and an impact that may have changed the second half of Earth history". Geoscience Frontiers. 4 (3): 247–261. Bibcode:2013GeoFr...4..247Y. doi: 10.1016/j.gsf.2012.07.003 .
  12. ↑ Farnsworth, Alexander; Lo, Y. T. Eunice; Valdes, Paul J.; Buzan, Jonathan R.; Mills, Benjamin J. W.; Merdith, Andrew S.; Scotese, Christopher R.; Wakeford, Hannah R. (25 September 2023). "Climate extremes likely to drive land mammal extinction during next supercontinent assembly". Nature Geoscience . 16 (10): 901–908. doi:10.1038/s41561-023-01259-3. ISSN   1752-0894 . Retrieved 25 October 2024.
  13. ↑ Nance, R. Damian (September 2022). "The supercontinent cycle and Earth's long-term climate". Annals of the New York Academy of Sciences. 1515 (1): 33–49. Bibcode:2022NYASA1515...33N. doi:10.1111/nyas.14849. PMC   9796656 . PMID   35762733.
  14. ↑ Scotese, Christopher (18 September 2014). Future Plate Motions & Pangea Proxima - Scotese Animation. YouTube. Archived from the original on 21 December 2021. Retrieved 3 October 2020.
  15. 1 2 Manaugh, Geoff; Twiley, Nicola (23 September 2013). "What Did the Continents Look Like Millions of Years Ago?". The Atlantic. Archived from the original on 25 September 2013. Retrieved 22 July 2014.
  16. ↑ Duarte, João; Schellart, Wouter; Rosas, Filipe (3 October 2016). "The future of Earth's oceans: consequences of subduction initiation in the Atlantic and implications for supercontinent formation". Geological Magazine. 155: 45–58. doi:10.1017/S0016756816000716. S2CID   132854162 – via Cambridge University Press.
  17. ↑ Huang, Chuan; Li, Zheng-Xiang; Zhang, Nan (28 October 2022). "Will Earth's next supercontinent assemble through the closure of the Pacific Ocean?". National Science Review. 9 (12) nwac205. doi:10.1093/nsr/nwac205. hdl: 20.500.11937/90604 .

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