Panthalassa , also known as the Panthalassic Ocean or Panthalassan Ocean (from Greek πᾶν "all" and θάλασσα "sea"), 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 ( c. 250 Ma ), 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 ("old Pacific") or Proto-Pacific because the Pacific Ocean is a direct continuation of Panthalassa.
44-443: The supercontinent Rodinia began to break up 870–845 Ma probably as a consequence of a superplume caused by mantle slab avalanches along the margins of the supercontinent. In a second episode c. 750 Ma the western half of Rodinia started to rift apart: western Kalahari and South China broke away from the western margins of Laurentia ; and by 720 Ma Australia and East Antarctica had also separated. In
88-455: A Precambrian supercontinent, which they named "Pangaea I." It was renamed "Rodinia" by McMenamin & McMenamin 1990 , who also were the first to produce a plate 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
132-483: A 2017 study using scanning electron microscopy revealed that this supposed structure actually represented tests that had been extensively modified by diagenetic processes. Instead, living fusulinids had low-magnesium hyaline tests with spherical nanograins up to 100 nm across, similar to the tests of the Rotaliida . These factors combined with overall shape of the test led these authors to suggest classification of
176-613: A Panthalassa Equatorial Counter Current. In the southern Panthalassa, the four currents of the subtropical gyre, the South Panthalassa Gyre, rotated counterclockwise. The South Equatorial Panthalassa Current flowed westward between the Equator and 10°S into the western, intense South Panthalassa Current. The South Polar Current then completed the gyre as the Southwestern Gondwana Current. Near
220-647: A large amount of sea-water into continental ice. Seamounts accreted in eastern Australia as parts of the New England orogen reveal the hotspot history of Panthalassa. From the Late Devonian to the Carboniferous, Gondwana and Panthalassa converged along the eastern margin of Australia along a west-dipping subduction system, which produced (west to east) a magmatic arc, a forearc basin, and an accretionary wedge. Subduction ceased along that margin in
264-931: A near-static position between 750 and 633 Ma. This latter solution predicts that break-up was confined to the Ediacaran period and produced the dramatic environmental changes that characterised the transition between the Precambrian and Phanerozoic . However, this theory has been widely criticized, as incorrect applications of paleomagnetic data have been pointed out. In 2009 UNESCO's International Geoscience Programme project 440, named "Rodinia Assembly and Breakup," concluded that Rodinia broke up in four stages between 825 and 550 Ma: The Rodinia hypothesis assumes that rifting did not start everywhere simultaneously. Extensive lava flows and volcanic eruptions of Neoproterozoic age are found on most continents, evidence for large scale rifting about 750 Ma. As early as 850 to 800 Ma,
308-738: A now extinct order of single-celled organisms, diversified extensively and developed gigantism —the genus Eopolydiexodina , for example, reached up to 16 cm (6.3 in) in size—and structural sophistication, including symbiont relationships with photosynthesising algae, during the Late Carboniferous and Permian, in what is known as the Carboniferous-Earliest Permian Biodiversification Event . The Capitanian mass extinction event c. 260 Ma , however, put an end to that development, with only dwarf taxa persisting throughout
352-691: A rift developed between the continental masses of present-day Australia, East Antarctica, India and the Congo and Kalahari cratons on one side and later Laurentia, Baltica, Amazonia and the West African and Rio de la Plata cratons on the other. This rift developed into the Adamastor Ocean during the Ediacaran . Around 550 Ma, near the boundary between the Ediacaran and Cambrian, the first group of cratons fused again with Amazonia, West Africa and
396-607: Is an extinct order within the Foraminifera in which the tests are traditionally considered to have been composed of microgranular calcite. Like all forams, they were single-celled organisms. In advanced forms the test wall was differentiated into two or more layers. Loeblich and Tappan , 1988, gives a range from the Lower Silurian to the Upper Permian , with the fusulinid foraminifera going extinct with
440-800: Is associated with the North Panthalassa High, which created Ekman convergence between 15°N and 50°N and Ekman divergence between 5°N and 10°N. A pattern developed that resulted in Sverdrup transport that went northward in divergence regions and southward in convergence regions. Western boundary currents resulted in an anti-cyclonic subtropical North Panthalassa gyre at mid-latitudes and a meridional anti-cyclonic circulation centred on 20°N. In tropical northern Panthalassa, trade winds created westward flows while equatorward flows were created by westerlies at higher latitudes. Consequently, trade winds moved water away from Gondwana towards Laurasia in
484-785: Is subducted and the ocean ridge that separated them probably subducted c. 60–55 Ma . Today, the region is dominated by the collision of the Australian Plate with a complex network of plate boundaries in south-east Asia, including the Sundaland block. Spreading along the Pacific-Phoenix ridge ended 83 Ma at the Osbourn Trough at the Tonga - Kermadec Trench . During the Permian, atolls developed near
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#1732794529241528-755: The Grenville orogeny in North America and the Dalslandian orogeny in Europe. Since then, many alternative reconstructions have been proposed for the configuration of the cratons in this supercontinent. Most of these reconstructions are based on the correlation of the orogens on different cratons. Though the configuration of the core cratons in Rodinia is now reasonably well known, recent reconstructions still differ in many details. Geologists try to decrease
572-715: The Permian–Triassic extinction event . While the latter is true, a more supported projected timespan is from the Mid-Carboniferous period. Thirteen superfamilies are presently recognised, based on taxa (families) included in the three superfamilies given in the Treatise. Three are based on families in the Parathuramminacea, 1964, and nine families in the Endothyracea, 1964. The Fusulinacea remains
616-638: The Permo-Triassic extinction event . The term "fusulinid" applies to any of the Fusulinida. The Fusulinida are fusulinids (sensu lato). However, the term "fusulinid" is often applied just to the fusiform Fusulinacea and not to the entire order. Members, especially of the Fusulinacea, are excellent index fossils for determining ages and correlating Upper Mississippian to Permian strata. In some places fusulinaceans may be so abundant as to be
660-672: The orogen . Permian to Cretaceous remains of the convergent margin, preserved as fragments in Zealandia ( New Zealand , New Caledonia , and the Lord Howe Rise ), were rifted off Australia during the Late Cretaceous to Early Tertiary break-up of eastern Gondwana and the opening of the Tasman Sea . The Cretaceous Junction Plate, located north of Australia, separated the eastern Tethys from Panthalassa. Panthalassa
704-477: The Cretaceous and later. The former margins of the ocean, however, contain allochthonous terranes with preserved Triassic–Jurassic intra-Panthalassic volcanic arcs, including Kolyma–Omolon (northeast Asia), Anadyr–Koryak (east Asia), Oku–Niikappu (Japan), and Wrangellia and Stikinia (western North America). Furthermore, seismic tomography is being used to identify subducted slabs in the mantle from which
748-681: The Early Jurassic the Pacific Plate opened originating from a triple junction between the Panthalassic Farallon , Phoenix , and Izanagi plates. Panthalassa can be reconstructed based on magnetic lineations and fracture zones preserved in the western Pacific. Most of the oceanic plates that formed the ocean floor of Panthalassa have been subducted and so traditional plate tectonic reconstructions based on magnetic anomalies can therefore be used only for remains from
792-573: The Equator on the mid-Panthalassic seamounts. As Panthalassa subducted along its western margin during the Triassic and Early Jurassic, those seamounts and palaeo-atolls were accreted as allochthonous limestone blocks and fragments along the Asian margin. One such migrating atoll complex now form a two-kilometre-long (1.2 mi) and 100-to-150-metre-wide (330–490 ft) body of limestone in central Kyushu , south-west Japan. Fusuline foraminifera ,
836-597: The Late Carboniferous and jumped eastward. From the Late Carboniferous to the Early Permian the New England orogen was dominated by an extensional setting related to a subduction to strike-slip transition. Subduction was re-initiated in the Permian and the granitic rocks of the New England Batholith were produced by a magmatic arc, indicating the presence of an active plate margin along most of
880-655: The Neoproterozoic break-up of Rodinia. The North American Cordillera is an accretionary orogen , which grew by the progressive addition of allochthonous terranes along this margin from the Late Palaeozoic. Devonian back-arc volcanism reveals how this eastern Panthalassic margin developed into the active margin it still is in the mid-Palaeozoic. Most of the continental fragments , volcanic arcs , and ocean basins added to Laurentia this way contained faunas of Tethyan or Asian affinity. Similar terranes added to
924-513: The Neoproterozoic, with its continental fragments reassembled to form Pannotia 633–573 Ma. In contrast with Pannotia, little is known about Rodinia's configuration and geodynamic history. 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
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#1732794529241968-472: The Permian until the final fusuline extinction in the Great Dying c. 252 Ma . Permian fusulines also developed a remarkable provincialism by which fusulines can be grouped into six domains. Because of the large size of Panthalassa, a hundred million years could separate the accretion of different groups of fusulines. Assuming a minimum accretion rate of 3 centimetres per year (1.2 in/year),
1012-623: The Rio de la Plata cratons during the Pan-African orogeny, which caused the development of Gondwana. In a separate rifting event about 610 Ma, the Iapetus Ocean formed. The eastern part of this ocean formed between Baltica and Laurentia, the western part between Amazonia and Laurentia. Because the timeframe of this separation and the partially contemporaneous Pan-African orogeny are difficult to correlate, it might be that all continental mass
1056-452: The breakup of Rodinia onwards. Rodinia is considered to have formed between 1.3 and 1.23 Ga and broke up again before 750 Ma. Rodinia was surrounded by the superocean Mirovia . According to J.D.A. Piper, Rodinia is one of two models for the configuration and history of the continental crust in the latter part of Precambrian times. The other is Paleopangea , Piper's own concept. Piper proposes an alternative hypothesis for this era and
1100-532: The crustal rocks rise up relative to their surroundings. This rising creates areas of higher altitude where the air is cooler and ice is less likely to melt with changes in season, and it may explain the evidence of abundant glaciation in the Ediacaran. The rifting of the continents created new oceans and seafloor spreading , which produces warmer, less dense oceanic crust . Lower-density, hot oceanic crust will not lie as deep as older, cool oceanic lithosphere. In periods with relatively large areas of new lithosphere,
1144-474: The fusulinids with the Globothalamea . A 2021 study further examined test microstructure and suggested instead that the forams examined in the 2017 study were not true fusulinids, but rather considered them their own group containing Nanicella and relatives. These authors considers that true fusulinids did in fact have microgranular tests. A third group consisting of forms related to Semitextularia
1188-557: The global climate around 717–635 Ma (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 . The idea that a supercontinent existed in the early Neoproterozoic arose in the 1970s, when geologists determined that orogens of this age exist on virtually all cratons . Examples are
1232-996: The increased rainfall may have reduced greenhouse gas levels to below the threshold required to trigger the period of extreme glaciation known as Snowball Earth . Increased volcanic activity also introduced into the marine environment biologically active nutrients, which may have played an important role in the earliest animals' development. [REDACTED] Africa [REDACTED] Antarctica [REDACTED] Asia [REDACTED] Australia [REDACTED] Europe [REDACTED] North America [REDACTED] South America [REDACTED] Afro-Eurasia [REDACTED] Americas [REDACTED] Eurasia [REDACTED] Oceania Fusulinida Archaediscacea Colaniellacea Earlandiacea Endothyracea Fusulinacea Geinitzinacea Moravamminacea Nodosinellacea Palaeotextulariacea Parathuraminacea Ptychocladiacea Tetrataxacea Tournayellacea The Fusulinida
1276-523: The largest foraminifera extant or extinct. Fusulinids are the earliest lineage of foraminifera thought to have evolved symbiosis with photosynthetic organisms. Fossils of fusulinids have been found on all continents except Antarctica ; they reached their greatest diversity during the Visean epoch of the Carboniferous . The group then gradually declined in diversity until finally going extinct during
1320-647: The location of former Panthalassic subduction zones can be derived. A series of such subduction zones, called Telkhinia, defines two separate oceans or systems of oceanic plates—the Pontus and Thalassa oceans. Named marginal oceans or oceanic plates include (clockwise) Mongol-Okhotsk (now a suture between Mongolia and Sea of Okhotsk), Oimyakon (between Asian craton and Kolyma-Omolon), Slide Mountain Ocean (British Columbia), and Mezcalera (western Mexico). The western margin (modern coordinates) of Laurentia originated during
1364-421: The marine life of its time. In the Cryogenian , Earth experienced large glaciations , and temperatures were at least as cool as today. Substantial parts of Rodinia may have been covered by glaciers or the southern polar ice cap . Low temperatures may have been exaggerated during the early stages of continental rifting. Geothermal heating peaks in crust about to be rifted, and since warmer rocks are less dense,
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1408-517: The northern Laurentia, in contrast, have affinities with Baltica, Siberia, and the northern Caledonies . The latter terranes were probably accreted along the eastern Panthalassa margin by a Caribbean – Scotia -style subduction system. The evolution of the Panthalassa–Tethys boundary is poorly known because little oceanic crust is preserved—both the Izanagi and the conjugate Pacific Ocean floor
1452-644: The northern Panthalassa Equatorial Current. When the western margins of Panthalassa were reached, intense western boundary currents would form the Eastern Laurasia Current. At mid-latitudes, the North Panthalassa Current would bring the water back east where a weak Northwestern Gondwana Current would finally close the gyre. The accumulation of water along the western margin, coupled with the Coriolis effect , would have created
1496-418: The ocean floors come up, causing the sea level to rise. The result was a greater number of shallower seas. The increased evaporation from the oceans' larger water area may have increased rainfall, which in turn increased the weathering of exposed rock. By inputting data on the ratio of stable isotopes O: O into computer models, it has been shown that in conjunction with quick weathering of volcanic rock ,
1540-453: The poles easterlies created a subpolar gyre that rotated clockwise. Rodinia Rodinia (from the Russian родина , rodina , meaning "motherland, birthplace" ) was a Mesoproterozoic and Neoproterozoic supercontinent that assembled 1.26–0.90 billion years ago (Ga) and broke up 750–633 million years ago (Ma). Valentine & Moores 1970 were probably the first to recognise
1584-448: The previous ones. This idea rejects that Rodinia ever existed as a transient supercontinent subject to progressive break-up in the late Proterozoic and instead that this time and earlier times were dominated by a single, persistent "Paleopangaea" supercontinent. As evidence, he suggests an observation that the palaeomagnetic poles from the continental crust assigned to this time conform to a single path between 825 and 633 Ma and latterly to
1628-587: The same in both sources (Treatise 1964 and Loeblich and Tappan, 1988). The term fusulinata has traditionally been used to refer to all palaeozoic foraminifera with multi-chambered tests. However, recent studies based on test microstructure have suggested that fusulinids may be polyphyletic and consist of at least three distinct lineages, and as such are in need of systematic revision. Traditionally, fusulinid tests were considered to have been composed of very small, tightly-packed calcite crystals with no preferred orientation—a so-called microgranular structure. However.
1672-400: The seamount chains on which those groups evolved would be separated by at least 3,000 km (1,900 mi). Those groups apparently evolved in completely different environments. A significant sea-level drop at the end of the Permian led to the end-Capitanian extinction event . The cause for the extinction is disputed, but a likely candidate is an episode of global cooling, which transformed
1716-548: The southwest with the Congo and Kalahari cratons ; and in the northeast with Australia , India and eastern Antarctica . The positions of Siberia and North and South China north of the North American craton differ strongly depending on the reconstruction: Little is known about the paleogeography before the formation of Rodinia. Paleomagnetic and geologic data are only definite enough to form reconstructions from
1760-475: The surface by upwelling in the east while the warmest water extended west into the Tethys Ocean. Subtropical gyres dominated the circulation pattern. The two hemispherical belts were separated by the undulating Intertropical Convergence Zone (ITCZ). In northern Panthalassa, there were mid-latitude westerlies north of 60°N with easterlies between 60°N and the Equator. Atmospheric circulation north of 30°N
1804-747: The uncertainties by collecting geological and paleomagnetical data. Most reconstructions show Rodinia's core formed by the North American Craton (the later paleocontinent of Laurentia ), surrounded in the southeast with the East European Craton (the later paleocontinent of Baltica ), the Amazonian Craton and the West African Craton ; in the south with the Río de la Plata and São Francisco cratons ; in
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1848-412: Was a hemisphere-sized ocean, much larger than the modern Pacific. It could be expected that the large size would result in relatively simple ocean current circulation patterns, such as a single gyre in each hemisphere, and a mostly stagnant and stratified ocean. Modelling studies, however, suggest that an east–west sea surface temperature (SST) gradient was present in which the coldest water was brought to
1892-490: Was again joined in one supercontinent between roughly 600 and 550 Ma. This hypothetical supercontinent is called Pannotia . Unlike later supercontinents, Rodinia was entirely barren. It existed before complex life colonized on dry land. Based on sedimentary rock analysis, Rodinia's formation happened when the ozone layer was not as extensive as it is now. Ultraviolet light discouraged organisms from inhabiting its interior. Nevertheless, its existence significantly influenced
1936-683: Was also found to have a distinct test microstructure, and was suggested to be a third lineage. The fusulinids are among the earliest calcareous-walled foraminifera; they appear in the fossil record during the Llandoverian epoch of the early Silurian . The earliest of these were microscopic, planispirally coiled, and evolute; later forms evolved a diversity of shapes including lenticular, globular, and elongated rice-shaped forms. Later species of fusulinids grew to much larger size, with some forms reaching 5 cm in length; reportedly, some specimens reach up to 14 cm in length, making them among
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