Pangaea

Pangaea or Pangea ( /pænˈdʒiːə/[1]) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras.[2][3] It assembled from earlier continental units approximately 335 million years ago, and it began to break apart about 175 million years ago.[4] In contrast to the present Earth and its distribution of continental mass, much of Pangaea was in the southern hemisphere and surrounded by a superocean, Panthalassa. Pangaea was the most recent supercontinent to have existed and the first to be reconstructed by geologists.

Pangaea continents
Map of Pangaea with modern continental outlines

Origin of the concept

Alfred Wegener ca.1924-30
Alfred Wegener c. 1924–1930

The name "Pangaea/Pangea" is derived from Ancient Greek pan (πᾶν, "all, entire, whole") and Gaia (Γαῖα, "Mother Earth, land").[5][10] The concept that the continents once formed a contiguous land mass was first proposed by Alfred Wegener, the originator of the scientific theory of continental drift, in his 1912 publication The Origin of Continents (Die Entstehung der Kontinente).[11] He expanded upon his hypothesis in his 1915 book The Origin of Continents and Oceans (Die Entstehung der Kontinente und Ozeane), in which he postulated that, before breaking up and drifting to their present locations, all the continents had formed a single supercontinent that he called the "Urkontinent".

The name "Pangea" occurs in the 1920 edition of Die Entstehung der Kontinente und Ozeane, but only once, when Wegener refers to the ancient supercontinent as "the Pangaea of the Carboniferous".[12] Wegener used the Germanized form "Pangäa", but the name entered German and English scientific literature (in 1922[13] and 1926, respectively) in the Latinized form "Pangaea" (of the Greek "Pangaia"), especially due to a symposium of the American Association of Petroleum Geologists in November 1926.[14]

Formation

Appalachian orogeny
Appalachian orogeny

The forming of supercontinents and their breaking up appears to have been cyclical through Earth's history. There may have been several others before Pangaea. The fourth-last supercontinent, called Columbia or Nuna, appears to have assembled in the period 2.0–1.8 Ga.[15][16] Columbia/Nuna broke up and the next supercontinent, Rodinia, formed from the accretion and assembly of its fragments. Rodinia lasted from about 1.1 billion years ago (Ga) until about 750 million years ago, but its exact configuration and geodynamic history are not nearly as well understood as those of the later supercontinents, Pannotia and Pangaea.

When Rodinia broke up, it split into three pieces: the supercontinent of Proto-Laurasia, the supercontinent of Proto-Gondwana, and the smaller Congo craton. Proto-Laurasia and Proto-Gondwana were separated by the Proto-Tethys Ocean. Next Proto-Laurasia itself split apart to form the continents of Laurentia, Siberia and Baltica. Baltica moved to the east of Laurentia, and Siberia moved northeast of Laurentia. The splitting also created two new oceans, the Iapetus Ocean and Paleoasian Ocean. Most of the above masses coalesced again to form the relatively short-lived supercontinent of Pannotia. This supercontinent included large amounts of land near the poles and, near the equator, only a relatively small strip connecting the polar masses. Pannotia lasted until 540 Ma, near the beginning of the Cambrian period and then broke up, giving rise to the continents of Laurentia, Baltica, and the southern supercontinent of Gondwana.

In the Cambrian period, the continent of Laurentia, which would later become North America, sat on the equator, with three bordering oceans: the Panthalassic Ocean to the north and west, the Iapetus Ocean to the south and the Khanty Ocean to the east. In the Earliest Ordovician, around 480 Ma, the microcontinent of Avalonia – a landmass incorporating fragments of what would become eastern Newfoundland, the southern British Isles, and parts of Belgium, northern France, Nova Scotia, New England, South Iberia and northwest Africa – broke free from Gondwana and began its journey to Laurentia.[17] Baltica, Laurentia, and Avalonia all came together by the end of the Ordovician to form a minor supercontinent called Euramerica or Laurussia, closing the Iapetus Ocean. The collision also resulted in the formation of the northern Appalachians. Siberia sat near Euramerica, with the Khanty Ocean between the two continents. While all this was happening, Gondwana drifted slowly towards the South Pole. This was the first step of the formation of Pangaea.[18]

The second step in the formation of Pangaea was the collision of Gondwana with Euramerica. By the Silurian, 440 Ma, Baltica had already collided with Laurentia, forming Euramerica. Avalonia had not yet collided with Laurentia, but as Avalonia inched towards Laurentia, the seaway between them, a remnant of the Iapetus Ocean, was slowly shrinking. Meanwhile, southern Europe broke off from Gondwana and began to move towards Euramerica across the newly formed Rheic Ocean. It collided with southern Baltica in the Devonian, though this microcontinent was an underwater plate. The Iapetus Ocean's sister ocean, the Khanty Ocean, shrank as an island arc from Siberia collided with eastern Baltica (now part of Euramerica). Behind this island arc was a new ocean, the Ural Ocean.

By the late Silurian, North and South China split from Gondwana and started to head northward, shrinking the Proto-Tethys Ocean in their path and opening the new Paleo-Tethys Ocean to their south. In the Devonian Period, Gondwana itself headed towards Euramerica, causing the Rheic Ocean to shrink. In the Early Carboniferous, northwest Africa had touched the southeastern coast of Euramerica, creating the southern portion of the Appalachian Mountains, the Meseta Mountains and the Mauritanide Mountains. South America moved northward to southern Euramerica, while the eastern portion of Gondwana (India, Antarctica and Australia) headed toward the South Pole from the equator. North and South China were on independent continents. The Kazakhstania microcontinent had collided with Siberia. (Siberia had been a separate continent for millions of years since the deformation of the supercontinent Pannotia in the Middle Carboniferous.)

Western Kazakhstania collided with Baltica in the Late Carboniferous, closing the Ural Ocean between them and the western Proto-Tethys in them (Uralian orogeny), causing the formation of not only the Ural Mountains but also the supercontinent of Laurasia. This was the last step of the formation of Pangaea. Meanwhile, South America had collided with southern Laurentia, closing the Rheic Ocean and forming the southernmost part of the Appalachians and Ouachita Mountains. By this time, Gondwana was positioned near the South Pole and glaciers were forming in Antarctica, India, Australia, southern Africa and South America. The North China block collided with Siberia by the Late Carboniferous, completely closing the Proto-Tethys Ocean.

By the early Permian, the Cimmerian plate split from Gondwana and headed towards Laurasia, thus closing the Paleo-Tethys Ocean, but forming a new ocean, the Tethys Ocean, in its southern end. Most of the landmasses were all in one. By the Triassic Period, Pangaea rotated a little and the Cimmerian plate was still travelling across the shrinking Paleo-Tethys, until the Middle Jurassic. The Paleo-Tethys had closed from west to east, creating the Cimmerian Orogeny. Pangaea, which looked like a C, with the new Tethys Ocean inside the C, had rifted by the Middle Jurassic, and its deformation is explained below.

Evidence of existence

Snider-Pellegrini Wegener fossil map
The distribution of fossils across the continents is one line of evidence pointing to the existence of Pangaea.

Fossil evidence for Pangaea includes the presence of similar and identical species on continents that are now great distances apart. For example, fossils of the therapsid Lystrosaurus have been found in South Africa, India and Antarctica, alongside members of the Glossopteris flora, whose distribution would have ranged from the polar circle to the equator if the continents had been in their present position; similarly, the freshwater reptile Mesosaurus has been found in only localized regions of the coasts of Brazil and West Africa.[19]

Additional evidence for Pangaea is found in the geology of adjacent continents, including matching geological trends between the eastern coast of South America and the western coast of Africa. The polar ice cap of the Carboniferous Period covered the southern end of Pangaea. Glacial deposits, specifically till, of the same age and structure are found on many separate continents that would have been together in the continent of Pangaea.[20]

Paleomagnetic study of apparent polar wandering paths also support the theory of a supercontinent. Geologists can determine the movement of continental plates by examining the orientation of magnetic minerals in rocks; when rocks are formed, they take on the magnetic properties of the Earth and indicate in which direction the poles lie relative to the rock. Since the magnetic poles drift about the rotational pole with a period of only a few thousand years, measurements from numerous lavas spanning several thousand years are averaged to give an apparent mean polar position. Samples of sedimentary rock and intrusive igneous rock have magnetic orientations that are typically an average of the "secular variation" in the orientation of magnetic north because their remanent magnetizations are not acquired instantaneously. Magnetic differences between sample groups whose age varies by millions of years is due to a combination of true polar wander and the drifting of continents. The true polar wander component is identical for all samples, and can be removed, leaving geologists with the portion of this motion that shows continental drift and can be used to help reconstruct earlier continental positions.[21]

The continuity of mountain chains provides further evidence for Pangaea. One example of this is the Appalachian Mountains chain, which extends from the southeastern United States to the Caledonides of Ireland, Britain, Greenland, and Scandinavia.[22]

Rifting and break-up

Pangea animation 03
Animation of the rifting of Pangaea

There were three major phases in the break-up of Pangaea. The first phase began in the Early-Middle Jurassic (about 175 Ma), when Pangaea began to rift from the Tethys Ocean in the east to the Pacific in the west. The rifting that took place between North America and Africa produced multiple failed rifts. One rift resulted in a new ocean, the North Atlantic Ocean.[22]

The Atlantic Ocean did not open uniformly; rifting began in the north-central Atlantic. The South Atlantic did not open until the Cretaceous when Laurasia started to rotate clockwise and moved northward with North America to the north, and Eurasia to the south. The clockwise motion of Laurasia led much later to the closing of the Tethys Ocean and the widening of the "Sinus Borealis", which later became the Arctic Ocean. Meanwhile, on the other side of Africa and along the adjacent margins of east Africa, Antarctica and Madagascar, new rifts were forming that would lead to the formation of the southwestern Indian Ocean that would open up in the Cretaceous.

The second major phase in the break-up of Pangaea began in the Early Cretaceous (150–140 Ma), when the minor supercontinent of Gondwana separated into multiple continents (Africa, South America, India, Antarctica, and Australia). The subduction at Tethyan Trench probably caused Africa, India and Australia to move northward, causing the opening of a "South Indian Ocean". In the Early Cretaceous, Atlantica, today's South America and Africa, finally separated from eastern Gondwana (Antarctica, India and Australia). Then in the Middle Cretaceous, Gondwana fragmented to open up the South Atlantic Ocean as South America started to move westward away from Africa. The South Atlantic did not develop uniformly; rather, it rifted from south to north.

Also, at the same time, Madagascar and India began to separate from Antarctica and moved northward, opening up the Indian Ocean. Madagascar and India separated from each other 100–90 Ma in the Late Cretaceous. India continued to move northward toward Eurasia at 15 centimeters (6 in) a year (a plate tectonic record), closing the eastern Tethys Ocean, while Madagascar stopped and became locked to the African Plate. New Zealand, New Caledonia and the rest of Zealandia began to separate from Australia, moving eastward toward the Pacific and opening the Coral Sea and Tasman Sea.

The third major and final phase of the break-up of Pangaea occurred in the early Cenozoic (Paleocene to Oligocene). Laurasia split when North America/Greenland (also called Laurentia) broke free from Eurasia, opening the Norwegian Sea about 60–55 Ma. The Atlantic and Indian Oceans continued to expand, closing the Tethys Ocean.

Meanwhile, Australia split from Antarctica and moved quickly northward, just as India had done more than 40 million years before. Australia is currently on a collision course with eastern Asia. Both Australia and India are currently moving northeast at 5–6 centimeters (2–3 in) a year. Antarctica has been near or at the South Pole since the formation of Pangaea about 280 Ma. India started to collide with Asia beginning about 35 Ma, forming the Himalayan orogeny, and also finally closing the Tethys Seaway; this collision continues today. The African Plate started to change directions, from west to northwest toward Europe, and South America began to move in a northward direction, separating it from Antarctica and allowing complete oceanic circulation around Antarctica for the first time. This motion, together with decreasing atmospheric carbon dioxide concentrations, caused a rapid cooling of Antarctica and allowed glaciers to form. This glaciation eventually coalesced into the kilometers-thick ice sheets seen today.[23] Other major events took place during the Cenozoic, including the opening of the Gulf of California, the uplift of the Alps, and the opening of the Sea of Japan. The break-up of Pangaea continues today in the Red Sea Rift and East African Rift.

Tectonic plate shift

Pangaea to present
The breakup of Pangaea over time

Pangaea's formation is now commonly explained in terms of plate tectonics. The involvement of plate tectonics in Pangaea's[3] separation helps to show how it did not separate all at once, but at different times, in sequences. Additionally, after these separations, it has also been discovered that the separated land masses may have also continued to break apart multiple times. The formation of each environment and climate on Pangaea is due to plate tectonics, and thus, it is as a result of these shifts and changes different climatic pressures were placed on the life on Pangaea. Although plate tectonics was paramount in the formation of later land masses, it was also essential in the placement, climate, environments, habitats, and overall structure of Pangaea.[24]

What can also be observed in relation to tectonic plates and Pangaea, is the formations to such plates. Mountains and valleys form due to tectonic collisions as well as earthquakes and chasms. Consequentially, this shaped Pangaea and animal adaptations. Furthermore, plate tectonics can contribute to volcanic activity,[25] which is responsible for extinctions and adaptations that have evidently affected life over time, and without doubt on Pangaea.

Life

Ammonites 180308
Example of an ammonite

For the approximately 160 million years Pangaea existed, many species did well, whereas others struggled. The Traversodonts[26] were an example of such successful animals. Plants dependent on spore reproduction were largely replaced by the gymnosperms, which reproduce through the use of seeds. Later on, insects (including beetles and cicadas) also thrived, during the Permian period 299 to 252 million years ago.[27] However, the Permian extinction at 252 Mya greatly impacted these insects in mass extinction, being the only mass extinction to affect insects. When the Triassic Period came, many reptiles were able to also thrive, including Archosaurs, which were an ancestor to modern-day crocodiles and birds.

Little is known about marine life during the existence of Pangaea. Scientists are unable to find substantial evidence or fossilized remains in order to assist them in answering such questions. However, a couple of marine animals have been determined to have existed at the time - the Ammonites and Brachiopods. Additionally, evidence pointing towards massive reefs with varied ecosystems, especially in the species of sponges and coral, have also been discovered.[28]

Climate change after Pangaea

The reconfiguration of continents and oceans after the breakup of Pangea changed the world's climate. There is scientific evidence that this change was drastic. When the continents separated and reformed themselves, it changed the flow of the oceanic currents and winds. The scientific reasoning behind all of the changes is Continental Drift. The theory of Continental Drift, created by Alfred Wegener, explained how the continents shifted Earth's surface and how that affected many aspects such as climate, rock formations found on different continents and plant and animal fossils.[29] Wegener studied plant fossils from the frigid Arctic of Svalbard, Norway. He determined that such plants were not adapted to a glacial climate. The fossils he found were from tropical plants that were adapted to thrive in warmer and tropical climates.[30] Because he would not assume that the plant fossils were capable of traveling to a different place, he suspected that Svalbard had had a warmer, less frigid climate in the past.[31]

When Pangaea separated, the reorganization of the continents changed the function of the oceans and seaways. The restructuring of the continents, changed and altered the distribution of warmth and coolness of the oceans. When North America and South America connected, it stopped equatorial currents from passing from the Atlantic Ocean to the Pacific Ocean.[32] Researchers have found evidence by using computer hydrological models to show that this strengthened the Gulf Stream by diverting more warm currents towards Europe. Warm waters at high latitudes led to an increased evaporation and eventually atmospheric moisture. Increased evaporation and atmospheric moisture resulted in increased precipitation. Evidence of increased precipitation is the development of snow and ice that covers Greenland, which led to an accumulation of the icecap. Greenland's growing ice cap led to further global cooling.[32] Scientists also found evidence of global cooling through the separation of Australia and Antarctica and the formation of the Antarctic Ocean. Ocean currents in the newly formed Antarctic or Southern Ocean created a circumpolar current.[32] The creation of the new ocean that caused a circumpolar current eventually led to atmospheric currents that rotated from west to east. Atmospheric and oceanic currents stopped the transfer of warm, tropical air and water to the higher latitudes. As a result of the warm air and currents moving northward, Antarctica cooled down so much that it became frigid.

Although many of Alfred Wegener's theories and conclusions were valid, scientists are constantly coming up with new innovative ideas or reasoning behind why certain things happen. Wegener's theory of Continental Drift was later replaced by the theory of tectonic plates.[33]

Implications of extinction

There is evidence to suggest that the deterioration of northern Pangaea contributed to the Permian Extinction, one of Earth's five major mass extinction events, which resulted in the loss of over 90% of marine and 70% of terrestrial species. There were three main sources of environmental deterioration that are believed to have had a hand in the extinction event.

The first of these sources is a loss of oxygen concentration in the ocean, which caused deep water regions called the lysocline to grow shallower. With the lysocline shrinking, there were fewer places for calcite to dissolve in the ocean, considering calcite only dissolves at deep ocean depths. This led to the extinction of carbonate producers such as brachiopods and corals that relied on dissolved calcite to survive. The second source is the eruption of the Siberian Traps, a large volcanic event that is argued to be the result of Pangaean tectonic movement.[34] This had several negative repercussions on the environment, including metal loading and excess atmospheric carbon. Metal loading, the release of toxic metals from volcanic eruptions into the environment, led to acid rain and general stress on the environment. These toxic metals are known to infringe on vascular plants’ ability to photosynthesize, which may have resulted in the loss of Permian-era flora. Excess carbon dioxide in the atmosphere is believed to be the main cause of the shrinking of lysocline areas.

The third cause of this extinction event that can be attributed to northern Pangaea is the beginnings of anoxic ocean environments, or oceans with very low oxygen concentrations. The mix of anoxic oceans and ocean acidification due to metal loading led to increasingly acidic oceans,[35] which ultimately led to the extinction of benthic species.[36]

See also

References

  1. ^ Oxford Dictionaries
  2. ^ Lovett, Richard A. (September 5, 2008). "Supercontinent Pangaea Pushed, Not Sucked, Into Place". National Geographic News.
  3. ^ a b "Pangea". Encyclopædia Britannica Inc. 2015.
  4. ^ Rogers, J.J.W.; Santosh, M. (2004), Continents and Supercontinents, Oxford: Oxford University Press, p. 146, ISBN 978-0-19-516589-0
  5. ^ "Pangaea". Online Etymology Dictionary.
  6. ^ Vergilius Mario, Publius. Georgicon, IV.462
  7. ^ Lucan. Pharsalia, I.679
  8. ^ Lewis, C.T. & al. "Pangaeus" in A Latin Dictionary. (New York), 1879.
  9. ^ Usener, H. Scholia in Lucani Bellum Civile, Vol. I. (Leipzig), 1869.
  10. ^ As "Pangaea", it appears in Greek mythology as a mountain battle site during the Titanomachia. As "Pangaeus", it was the name of a specific mountain range in southern Thrace. "Pangaea" also appears in Vergil's Georgics[6] and Lucan's Pharsalia[7][8] The scholiast on Lucan glossed Pangaea id est totum terra—"Pangaea: that is, all land"—as having received its name on account of its smooth terrain and unexpected fertility.[9]
  11. ^ Alfred Wegener: Die Entstehung der Kontinente. Dr. A. Petermann's Mitteilungen aus Justus Perthes' Geographischer Anstalt, 58(1): Gotha 1912
  12. ^ See:
    • Wegener, Alfred, Die Entstehung der Kontinente und Ozeane, 2nd ed. (Braunschweig, Germany: F. Vieweg, 1920), p. 120: "Schon die Pangäa der Karbonzeit hatte so einen Vorderrand ... " [Already the Pangea of the Carboniferous era had such a leading edge ...] (In the 1922 edition, see p. 130.)
    • Wegener, A.; Krause, R.; Thiede, J. (2005). "Kontinental-Verschiebungen: Originalnotizen und Literaturauszüge"(Continental drift: the original notes and quotations). Berichte zur Polar- und Meeresforschung (Reports on Polar and Marine Research) 516. Alfred-Wegener-Institut: Bremerhaven, p. 4, n. 2
  13. ^ Jaworski, Erich (1922). "Die A. Wegenersche Hypothese der Kontinentalverschiebung". Geologische Rundschau. 13 (3): 273–296. Bibcode:1922GeoRu..13..273J. doi:10.1007/bf01799790.
  14. ^ Willem A. J. M. van Waterschoot van der Gracht (and 13 other authors): Theory of Continental Drift: a Symposium of the Origin and Movements of Land-masses of both Inter-Continental and Intra-Continental, as proposed by Alfred Wegener. X + 240 S., Tulsa, Oklahoma, United States, The American Association of Petroleum Geologists & London, Thomas Murby & Co.
  15. ^ Zhao, Guochun; Cawood, Peter A.; Wilde, Simon A.; Sun, M. (2002). "Review of global 2.1–1.8 Ga orogens: implications for a pre-Rodinia supercontinent". Earth-Science Reviews. 59 (1–4): 125–162. Bibcode:2002ESRv...59..125Z. doi:10.1016/S0012-8252(02)00073-9.
  16. ^ Zhao, Guochun; Sun, M.; Wilde, Simon A.; Li, S.Z. (2004). "A Paleo-Mesoproterozoic supercontinent: assembly, growth and breakup". Earth-Science Reviews. 67 (1–2): 91–123. Bibcode:2004ESRv...67...91Z. doi:10.1016/j.earscirev.2004.02.003.
  17. ^ Stanley, Steven (1998). Earth System History. USA. pp. 355–359.
  18. ^ Stanley, Steven (1998). Earth System History. USA. pp. 386–392.
  19. ^ Benton, M.J. (2005) Vertebrate Palaeontology. Third edition, Oxford, p. 25.
  20. ^ Murck, Barbara W. and Skinner, Brian J. (1999) Geology Today: Understanding Our Planet, Study Guide, Wiley, ISBN 978-0-471-32323-5
  21. ^ Kearey, Philip; Klepeis, Keith A. and Vine, Frederick J. (2009). Global Tectonics (3rd. ed), pp. 66–67. Chichester:Wiley. ISBN 978-1-4051-0777-8
  22. ^ a b Merali, Zeeya and Skinner, Brian J. (2009) Visualizing Earth Science, Wiley, ISBN 047174705X
  23. ^ Deconto, Robert M.; Pollard, David (2003). "Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2". Nature. 421 (6920): 245–9. Bibcode:2003Natur.421..245D. doi:10.1038/nature01290. PMID 12529638.
  24. ^ "Facts About Pangaea, Ancient Supercontinent". LiveScience.com. Retrieved 2015-10-29.
  25. ^ "Pangaea to the Present Lesson #2 | Volcano World | Oregon State University". volcano.oregonstate.edu. Retrieved 2015-10-29.
  26. ^ Ranivoharimanana, Lovasoa; Kammerer, Christian F.; Flynn, John J.; Wyss, André R. (2011). "New material of Dadadon isaloi (Cynodontia, Traversodontidae) from the Triassic of Madagascar". Journal of Vertebrate Paleontology. 31 (6): 1292–1302. doi:10.1080/02724634.2011.618154.
  27. ^ "Permian Period: Climate, Animals & Plants". LiveScience.com. Retrieved 2015-10-29.
  28. ^ Klein, George (1994). Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent. Geological Society of America. p. 190.
  29. ^ "Alfred Wegener". www.ucmp.berkeley.edu. Retrieved 2015-10-29.
  30. ^ Tabor, Neil J.; Poulsen, Christopher J. (2008). "Palaeoclimate across the Late Pennsylvanian–Early Permian tropical palaeolatitudes: A review of climate indicators, their distribution, and relation to palaeophysiographic climate factors". Palaeogeography, Palaeoclimatology, Palaeoecology. 268 (3–4): 293–310. Bibcode:2008PPP...268..293T. doi:10.1016/j.palaeo.2008.03.052.
  31. ^ "continental drift". National Geographic Education. June 2015. Retrieved 2015-10-29.
  32. ^ a b c "Sea Level Change". cgge.aag.org. Retrieved 2015-10-29.
  33. ^ "Continental Drift: Theory & Definition". LiveScience.com. Retrieved 2015-10-29.
  34. ^ Ivanov, A. V. (2007). Evaluation of different models for the origin of the Siberian traps. GSA Special Papers. 430. pp. 669–691. CiteSeerX 10.1.1.509.1901. doi:10.1130/2007.2430(31). ISBN 978-0-8137-2430-0.
  35. ^ Beauchamp, Benoit; Grasby, Stephen E. (2012). "Permian lysocline shoaling and ocean acidification along NW Pangea led to carbonate eradication and chert expansion". Palaeogeography, Palaeoclimatology, Palaeoecology. 350–352: 73–90. Bibcode:2012PPP...350...73B. doi:10.1016/j.palaeo.2012.06.014.
  36. ^ Grasby, Stephen E.; Beauchamp, Benoit; Bond, David P.G.; Wignall, Paul; Talavera, Cristina; Galloway, Jennifer M.; Piepjohn, Karsten; Reinhardt, Lutz; Blomeier, Dierk (2015). "Progressive environmental deterioration in northwestern Pangea leading to the latest Permian extinction". Geological Society of America Bulletin. 127 (9–10): 1331–1347. Bibcode:2015GSAB..127.1331G. doi:10.1130/B31197.1.

External links

Breaking Pangaea

Breaking Pangaea was an emo pop band from Philadelphia, PA. The band gained a small but passionate following from early 2000 to 2003, especially among college students.

The band released their debut EP and full length album on Florida's Undecided Records and released a follow up EP on Equal Vision Records.

Central Pangean Mountains

The Central Pangean Mountains were an extensive northeast-southwest trending mountain range in the central portion of the supercontinent Pangaea during the Triassic period. They were formed as a result of collision between the minor supercontinents Laurussia and Gondwana during the formation of Pangaea. Remnants of this massive mountain range include the Appalachian Mountains of North America, the Little Atlas of Morocco, Africa and much of the Scottish Highlands including Ben Nevis.

A number of mountain building periods were involved in the formation of the Central Pangean Mountains, including the Acadian, Caledonian, Alleghenian and Mauritanide orogenies.

Continental fragment

Continental crustal fragments, partially synonymous with microcontinents, are fragments of continents that have been broken off from main continental masses forming distinct islands, often several hundred kilometers from their place of origin. All continents are fragments; the terms "continental fragment" and "microcontinent" are usually restricted to those smaller than Australia, due to Australia being the smallest continent. They are not known to contain a craton or fragment of a craton. Continental fragments include some seamounts and underwater plateaus.

Some microcontinents are fragments of Gondwana or other ancient cratonic continents: these include Madagascar; the northern Mascarene Plateau, which includes the Seychelles; the island of Timor, etc. Other islands, such as several in the Caribbean Sea, are composed largely of granitic rock as well, but all continents contain both granitic and basaltic crust, and there is no clear dividing line between islands and microcontinents under such a definition. The Kerguelen Plateau is a large igneous province formed by a volcanic hot spot; however, it was associated with the breakup of Gondwana and was for a time above water, so it is considered a microcontinent, though not a continental fragment. Other hotspot islands such as Iceland and Hawaii are considered neither microcontinents nor continental fragments. Not all islands can be considered microcontinents: the British Isles, Sri Lanka, Borneo, and Newfoundland, for example, are each within the continental shelf of an adjacent continent, separated from the mainland by inland seas flooding its margins.

Several islands in the eastern Indonesian archipelago are considered continental fragments, although this designation is controversial. These include Sumba, Timor (Nusa Tenggara), Banggai-Sulu Islands (Sulawesi), Obi, southern Bacan, and the Buru-Seram-Ambon complex (Maluku).

Continental fragments (pieces of Pangaea smaller than Sahul)Azores Microcontinent – Portuguese archipelago in the North Atlantic Ocean

Bollons Seamount – A continental fragment seamount southeast of New Zealand

East Tasman Plateau – A submerged microcontinent south east of Tasmania

Gilbert Seamount

Jan Mayen Microcontinent – A fragment of continental crust within the oceanic part of the western Eurasian Plate northeast of Iceland

Madagascar

Mascarene Plateau – A submarine plateau in the Indian Ocean, north and east of Madagascar.

Mauritia – A Precambrian microcontinent that broke away as India and Madagascar separated

Parts of Wallaby Plateau

Possibly Sumba, Timor, and other islands of eastern Indonesia; Sulawesi was formed via the subduction of a microcontinent

Rockall Plateau

Socotra – The largest of four islands of the Socotra archipelago, Yemen

South Orkney Microcontinent

Zealandia – Mostly submerged mass of continental crust containing New Zealand and New CaledoniaOther microcontinents (formed post-Pangaea)Barbados

Cuba, Hispaniola, Jamaica, and other granitic Caribbean islands

Kerguelen Plateau – Submerged micro-continent in the southern Indian Ocean

FabricLive.73

FabricLive.73 is a DJ mix album by electronic artist Pangaea. It was released in 2014, as part of the FabricLive Mix Series.

Geological history of Earth

The geological history of Earth follows the major 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.

Earth was initially molten due to extreme volcanism and frequent collisions with other bodies. Eventually, the outer layer of the planet cooled to form a solid crust when water began accumulating in the atmosphere. The Moon formed soon afterwards, possibly as a result of the impact of a planetoid with the Earth. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered from comets, produced the oceans.

As the surface continually reshaped itself over hundreds of millions of years, continents formed and broke apart. They migrated across the surface, occasionally combining to form a supercontinent. Roughly 750 million years ago, the earliest-known supercontinent Rodinia, began to break apart. The continents later recombined to form Pannotia, 600 to 540 million years ago, then finally Pangaea, which broke apart 200 million years ago.

The present pattern of ice ages began about 40 million years ago, then intensified at the end of the Pliocene. The polar regions have since undergone repeated cycles of glaciation and thaw, repeating every 40,000–100,000 years. The last glacial period of the current ice age ended about 10,000 years ago.

Gondwana

Gondwana ( ), (or Gondwanaland), was a supercontinent that existed from the Neoproterozoic (about 550 million years ago) until the Jurassic (about 180 million years ago).

It was formed by the accretion of several cratons. Eventually, Gondwana became the largest piece of continental crust of the Paleozoic Era, covering an area of about 100,000,000 km2 (39,000,000 sq mi). During the Carboniferous Period, it merged with Laurussia to form a larger supercontinent called Pangaea. Gondwana (and Pangaea) gradually broke up during the Mesozoic Era. The remnants of Gondwana make up about two thirds of today's continental area, including South America, Africa, Antarctica, Australia, and the Indian Subcontinent.

The formation of Gondwana began c. 800 to 650 Ma with the East African Orogeny, the collision of India and Madagascar with East Africa,and was completed c. 600 to 530 Ma with the overlapping Brasiliano and Kuunga orogenies, the collision of South America with Africa and the addition of Australia and Antarctica, respectively.

Laurasia

Laurasia () was the more northern of two supercontinents (the other being Gondwana) that formed part of the Pangaea supercontinent around 335 to 175 million years ago (Mya). It separated from Gondwana 215 to 175 Mya (beginning in the late Triassic period) during the breakup of Pangaea, drifting farther north after the split.

The name combines the names of Laurentia, the name given to the North American craton, and Eurasia. As suggested by the geologic naming, Laurasia included most of the land masses which make up today's continents of the Northern Hemisphere, chiefly Laurentia, Baltica, Siberia, Kazakhstania, and the North China and East China cratons.

Novopangaea

Novopangaea or Novopangea (Greco-Latin for "New Pangaea") is a possible future supercontinent postulated by Roy Livermore (now at the University of Cambridge) in the late 1990s. It assumes closure of the Pacific, docking of Australia with East Asia, and northward motion of Antarctica.

PANGAEA (data library)

PANGAEA - Data Publisher for Earth & Environmental Science is a digital data library and a data publisher for earth system science. Data can be georeferenced in time (date/time or geological age) and space (latitude, longitude, depth/height).

Scientific data are archived with related metainformation in a relational database (Sybase) through an editorial system. Data are in Open Access and are distributed through web services in standard formats on the Internet through various search engines and portals. Data set descriptions (metadata) are conform to the ISO 19115 standard and are served in various further formats (e.g. Directory Interchange Format, Dublin Core). They include a bibliographic citation and are persistently identified using Digital Object Identifiers (DOI). Identifier provision and long-term availability of data sets via library catalogs is ensured through a cooperation with the German National Library of Science and Technology (TIB). Retrieval of data sets is provided through a full text search engine (based on Apache Lucene / panFMP). For efficient data compilations a data warehouse is operated. Data descriptions are available through various protocols (OAI-PMH, Web Catalog Service).

PANGAEA is hosted by the Alfred Wegener Institute for Polar and Marine Research (AWI), Bremerhaven and the Center for Marine Environmental Sciences (MARUM), Bremen in Germany. The system is used by various international research projects from public funding as data repository and by the World Data Center for Marine Environmental Sciences (WDC-MARE) as long-term archive. The system was initially developed since 1987 and is operational on the Internet since 1995.

The MediaWiki software is used to operate a wiki as PANGAEA manual and reference.

PANGAEA is also listed in re3data.org.

Palaeogeography

Palaeogeography (or paleogeography) is the study of historical geography, generally physical landscapes. Palaeogeography can also include the study of human or cultural environments. When the focus is specifically on the study of landforms, the term paleogeomorphology is sometimes used instead.

Paleogeography yields information that is crucial to scientific understanding in a variety of contexts. For example, paleogeographic analysis of sedimentary basins plays a key role in the field of petroleum geology, because the ancient geomorphological environments of the Earth's surface are preserved in the stratigraphic record. Paleogeographers also study the sedimentary environment associated with fossils for clues to the evolutionary development of extinct species. And paleogeographic evidence contributed to the development of continental drift theory, and continues to inform current plate tectonic theories, yielding information about the shape and latitudinal location of supercontinents such as Pangaea and ancient oceans such as Panthalassa, thus enabling the reconstruction of prehistoric continents and oceans.

Pangaea (album)

Pangaea is a live album by American jazz trumpeter, composer, and bandleader Miles Davis. It was originally released as a double album in 1976 by CBS Sony in Japan.

Recorded during Davis' electric period, the album captures the second of two concerts he performed on February 1, 1975, at Osaka's Festival Hall. As with the first concert (captured on the 1975 album Agharta), Davis led a band featuring guitarists Pete Cosey and Reggie Lucas, saxophonist Sonny Fortune, bassist Michael Henderson, drummer Al Foster, and percussionist James Mtume.

Pangaea (sculpture)

Pangaea is a public art work by artist Michaela Mahady, located on the east side of Milwaukee, Wisconsin on the campus of the University of Wisconsin–Milwaukee. The mixed media work incorporates concrete, brick, stone, steel, ceramic tile and colored leaded glass into a pavilion crowned with images of technology. Pangaea represents the global nature of today's world. The artwork is located in a courtyard behind the Sheldon B. Lubar School of Business and was funded by the Wisconsin Arts Board's Percent for Art program.

Pangaea Ultima

Pangaea Ultima (also called Pangaea Proxima, Neopangaea, and Pangaea II) is a possible future supercontinent configuration. Consistent with the supercontinent cycle, Pangaea Ultima could occur within the next 250 million years. This potential configuration, hypothesized by Christopher Scotese, 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. The concept was based on examination of past cycles of formation and breakup of supercontinents, not on current 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."Supercontinents describe the merger of all, or nearly all, of the Earth's landmass into a single contiguous continent. In the Pangaea Ultima 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 of Pangaea Proxima would probably become a semi-arid desert prone to extreme temperatures.

Rhaetian

See Raetians for the Alpine people of antiquity. See Raetian language for their language.The Rhaetian is, in geochronology, the latest age of the Triassic period or in chronostratigraphy the uppermost stage of the Triassic system. It lasted from 208.5 to 201.3 million years ago. It was preceded by the Norian and succeeded by the Hettangian (the lowermost stage or earliest age of the Jurassic).In this age, Pangaea began to break up, though the Atlantic Ocean was not yet formed.

Rodinia

Rodinia (from the Russian родить, rodít, meaning "to beget, to give birth", or родина, ródina, meaning "motherland, birthplace") is a Neoproterozoic supercontinent that was assembled 1.1–0.9 billion years ago and broken up 750–633 million years ago.Valentine & Moores 1970 were probably the first to recognise a Precambrian supercontinent, which they named 'Pangaea I'. It was renamed 'Rodinia' by McMenamin & McMenamin 1990 who also were the first to produce a reconstruction and propose a temporal framework for the supercontinent.Rodinia formed at c. 1.23 Ga by accretion and collision of fragments produced by breakup of an older supercontinent, Columbia, assembled by global-scale 2.0–1.8 Ga collisional events.Rodinia broke up in the Neoproterozoic with its continental fragments reassembled to form Pannotia 633–573 million years ago. In contrast with Pannotia, little is known yet about the exact configuration and geodynamic history of Rodinia. Paleomagnetic evidence provides some clues to the paleolatitude of individual pieces of the Earth's crust, but not to their longitude, which geologists have pieced together by comparing similar geologic features, often now widely dispersed.

The extreme cooling of the global climate around 717–635 million years ago (the so-called Snowball Earth of the Cryogenian Period) and the rapid evolution of primitive life during the subsequent Ediacaran and Cambrian periods are thought to have been triggered by the breaking up of Rodinia or to a slowing down of tectonic processes.

South China (continent)

South China, also known as South China Craton, South Chinese Craton, or Yangtze Craton, was an ancient continent (craton) that contained today's South and Southeast China, Indochina, and parts of Southeast Asia (i.e. Borneo and adjacent islands). South China had been part of past supercontinents, including Rodinia, Pannotia, Gondwana, Pangaea and Laurasia.

Supercontinent

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, many earth scientists use a different definition: "a clustering of nearly all continents", which leaves room for interpretation and is easier to apply to Precambrian times.Supercontinents have assembled and dispersed multiple times in the geologic past (see table). According to the modern definitions, a supercontinent does not exist today. The supercontinent Pangaea is the collective name describing all of the continental landmasses when they were most recently near to one another. The positions of continents have been accurately determined back to the early Jurassic, shortly before the breakup of Pangaea (see animated image). The earlier continent Gondwana is not considered a supercontinent under the first definition, since the landmasses of Baltica, Laurentia and Siberia were separate at the time.

Triassic

The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.9 million years ago (Mya), to the beginning of the Jurassic Period 201.3 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events.Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Therapsids and archosaurs were the chief terrestrial vertebrates during this time. A specialized subgroup of archosaurs, called dinosaurs, first appeared in the Late Triassic but did not become dominant until the succeeding Jurassic Period.The first true mammals, themselves a specialized subgroup of therapsids, also evolved during this period, as well as the first flying vertebrates, the pterosaurs, who, like the dinosaurs, were a specialized subgroup of archosaurs. The vast supercontinent of Pangaea existed until the mid-Triassic, after which it began to gradually rift into two separate landmasses, Laurasia to the north and Gondwana to the south.

The global climate during the Triassic was mostly hot and dry, with deserts spanning much of Pangaea's interior. However, the climate shifted and became more humid as Pangaea began to drift apart. The end of the period was marked by yet another major mass extinction, the Triassic–Jurassic extinction event, that wiped out many groups and allowed dinosaurs to assume dominance in the Jurassic.

The Triassic was named in 1834 by Friedrich von Alberti, after the three distinct rock layers (tri meaning "three") that are found throughout Germany and northwestern Europe—red beds, capped by marine limestone, followed by a series of terrestrial mud- and sandstones—called the "Trias".

Yangtze Plate

The Yangtze Plate, also called the South China Block or the South China Subplate, comprises the bulk of southern China. It is separated on the east from the Okinawa Plate by a rift that forms the Okinawa Trough which is a back-arc basin, on the south by the Sunda Plate and the Philippine Sea Plate, and on the north and west by the Eurasian Plate. The Longmenshan Fault on the latter border was the site of the 2008 Wenchuan earthquake.The Yangtze Plate was formed by the disaggregation of the Rodinia Supercontinent 750 million years ago, in the Neoproterozoic era. South China rifted away from the Gondwana supercontinent in the Silurian. During the formation of the great supercontinent Pangaea, South China was a smaller, separate continent located off the east coast of the supercontinent and drifting northward. In the Triassic the Yangtze Plate collided with the North China Plate, thereby connecting with Pangaea, and formed the Sichuan basin. In the Cenozoic the Yangtze Plate was influenced by the collision of the Indian and Eurasian plates creating the uplifting of the Longmen Mountains. Its southward motion is accommodated along the Red River fault.

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