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32-528: The 13-km-long massif is composed of Lower Cretaceous and Upper Jurassic limestones that dip continuously southwest to the Black Sea and plunge below the modern sea level. The area is densely wooded, with large areas of both coniferous forest and mixed woodland. The Arabika contains a number of remarkable caves, gorges, wells, and precipices, including the Veryovkina Cave and Voronya Cave ,

64-614: 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

96-649: 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

128-740: 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

160-561: Is a stub . You can help Misplaced Pages by expanding it . This Georgia location article is a stub . You can help Misplaced Pages by expanding it . Lower Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous ( chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous . It is usually considered to stretch from 145  Ma to 100.5 Ma. Proposals for

192-801: 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

224-716: Is being used to identify subducted slabs in the mantle from which 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

256-786: 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

288-666: The Late Jurassic continued to persist. Angiosperms (flowering plants) appeared for the first time during the Early Cretaceous; Archaefructaceae , one of the oldest fossil families (124.6 Ma) was found in the Yixian Formation , China. This time also saw the evolution of the first members of the Neornithes (modern birds). Sinodelphys , a 125 Ma-old boreosphenidan mammal found in

320-865: The Panthalassic Ocean the Pacific Plate continued to grow; the Arctic Alaska-Chukotka terrane formed the Bering Strait. Continued rifting opened new basins in the Indian Ocean, separating India, Antarctica, and Australia. By 110 Ma the Mid-Atlantic Ridge reached south into the Proto-Caribbean and South Atlantic, effectively separating South America from Africa, and continued rifting in

352-606: The Prudhoe Bay Oil Field has been interpreted as being sourced from the Triassic Shublik Formation shale and carbonate, Lower Cretaceous highly radioactive zone shale, and Lower Jurassic Kingak Shale . [REDACTED] Geology portal [REDACTED] Palaeontology portal Panthalassa Panthalassa , also known as the Panthalassic Ocean or Panthalassan Ocean (from Greek πᾶν "all" and θάλασσα "sea"),

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384-674: 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

416-575: 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 ,

448-597: 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

480-655: 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

512-473: 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),

544-654: The South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Ontong Java Plateau today covers an area of 1,860,000 km . In the Indian Ocean another LIP began to form at c. 120 Ma, the Kerguelen Plateau – Broken Ridge , together covering 2,300,000 km . Another LIP on the Liaodong Peninsula , China, c.  131–117 Ma, lasted for 10 million years. It

576-577: The Yixian Formation, China, is one of the oldest mammal fossils found. The fossil location indicates early mammals began to diversify from Asia during the Early Cretaceous. Sinodelphys was more closely related to metatherians (marsupials) than eutherians (placentals) and had feet adapted for climbing trees. Steropodon is the oldest monotreme (egg-lying mammal) discovered. It lived in Gondwana (now Australia) at 105 Ma. Oil in

608-706: The banks of Newfoundland and to connect to the Canada Basin in the Arctic Ocean. With the opening of the Labrador Sea , Greenland became a separate tectonic plate and Laurentia became North America . The Proto-Caribbean Sea continued to grow and the Paraná-Etendeka LIP began to break Africa into three pieces. The Falkland Plateau broke off from southern Africa at 132 Ma and Madagascar ceased to move independently c. 120 Ma. In

640-532: 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. 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

672-630: The exact age of the Barremian–Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining early Aptian Oceanic Anoxic Event 1a (OAE1a) was carbon isotope dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java - Manihiki - Hikurangi large igneous province, emplaced in

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704-518: 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

736-644: 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

768-610: The northern end completed the longitudinal extent of the Atlantic. In Panthalassa the Ontong-Java Mega-LIP resulted in the formation of new tectonic plates and in the Indian Ocean the Kerguelen LIP began to push India northward. During this time many new types of dinosaur appeared or came into prominence, including ceratopsians , spinosaurids , carcharodontosaurids and coelurosaurs , while survivors from

800-401: 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

832-661: 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 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

864-476: 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

896-647: 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 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

928-486: The world's deepest caves. Alexander Kruber was the first to explore some of these features in 1909. According to Rebecca Felix, the Arabica's "towering heights of limestone suggest the possibility of amazingly deep caves, boring the length of the massif and into the earth below its base". 43°25′N 40°20′E  /  43.41°N 40.34°E  / 43.41; 40.34 This Abkhazia location article

960-412: 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

992-801: Was the result of the subduction of the Kula and Pacific plates, which was probably caused by a superplume . During the opening of the South Atlantic the Paraná–Etendeka LIP produced 1.5 million km of basalts and rhyolites , beginning 133 Ma and lasting for a million years. The opening of the Central Atlantic continued as the Mid-Atlantic Ridge spread north to separate the Iberian Peninsula from

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1024-482: 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

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