1.
Pangaea
–
Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, 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, the name Pangaea/Pangea is derived from Ancient Greek pan and Gaia. The name Pangea occurs in the 1920 edition of Die Entstehung der Kontinente und Ozeane, but only once, the forming of supercontinents and their breaking up appears to have been cyclical through Earths history. There may have many others before 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, 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, 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. Baltica, Laurentia, and Avalonia all came together by the end of the Ordovician to form a supercontinent called Euramerica or Laurussia. 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 and this was the first step of the formation of Pangaea. The second step in the formation of Pangaea was the collision of Gondwana with Euramerica, by Silurian time,440 Ma, Baltica had already collided with Laurentia, forming Euramerica. Avalonia had not yet collided with Laurentia, but as Avalonia inched towards Laurentia, 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 Oceans sister ocean, the Khanty Ocean, shrank as an island arc from Siberia collided with eastern Baltica. Behind this island arc was a new ocean, the Ural Ocean, by late Silurian time, 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, South America moved northward to southern Euramerica, while the eastern portion of Gondwana headed toward the South Pole from the equator. North and South China were on independent continents, the Kazakhstania microcontinent had collided with Siberia
2.
Laurasia
–
Laurasia was the more northern of two supercontinents that formed part of the Pangaea supercontinent around 335 to 175 million years ago. It separated from Gondwana 215 to 175 Mya during the breakup of Pangaea, the name combines the names of Laurentia, the name given to the North American craton, and Eurasia. To avoid confusion with the Mesozoic continent, this is referred to as Proto-Laurasia and it is believed that Laurasia did not break up again before it recombined with the southern continents to form the late Precambrian supercontinent of Pannotia, which remained until the early Cambrian. Laurasia was assembled, then broken up, due to the actions of plate tectonics, continental drift, and seafloor spreading. By the Devonian, North China was located near the Arctic Circle, no evidence, though, exists for any large-scale Carboniferous glaciation of the northern continents. Siberia moved southwards and joined with Kazakhstania, a continental region believed today to have been created during the Silurian by extensive volcanism. North China became, as it drifted southwards from near-Arctic latitudes, around 200 million years ago, Pangaea started to break up. Between eastern North America and northwest Africa, a new ocean formed - the Atlantic Ocean, though Greenland, the separation of Europe and Greenland occurred around 55 million years ago. Laurasia finally divided into the continents after which it is named, alexander du Toit Alfred Wegener Avalonia
3.
Gondwana
–
In paleogeography, Gondwana, also Gondwanaland, is the name given to an ancient supercontinent. It is believed to have sutured about 600 to 530 million years ago, Gondwana formed prior to Pangaea, and later became part of it. Around 335 to 250 million years ago Gondwana and Laurasia joined together to form the supercontinent Pangaea, Gondwana then separated from Laurasia in the breakup of Pangaea, drifting farther south after the split. Gondwana itself then also broke apart, the continent of Gondwana was named by Austrian scientist Eduard Suess, after the Gondwana region of central northern India which is derived from Sanskrit for forest of the Gonds. The name had previously used in a geological context, first by H. B. From which the Gondwana sedimentary sequences are also described, for example, the plant family Proteaceae, known only from southern South America, South Africa, Australia, and New Zealand, is considered to have a Gondwanan distribution. This pattern is considered to indicate an archaic, or relict. The assembly of Gondwana was a protracted process, several orogenies led to its final amalgamation 550 to 500 million years ago at the end of the Ediacaran, and into the Cambrian. These include the Brasiliano Orogeny, the East African Orogeny, the Malagasy Orogeny, the final stages of Gondwanan assembly overlapped with the opening of the Iapetus Ocean between Laurentia and western Gondwana. During this interval, the Cambrian explosion occurred and this is the Famatinian block and it formerly continued the line of the Appalachians southwards. One of the sites of Gondwanan amalgamation was the East African Orogeny. The East African Orogeny at about 650–630 Mya affected a part of Arabia, north-eastern Africa, East Africa. Collins and Windley propose that in this orogeny, Azania collided with the Congo–Tanzania–Bangweulu Block, the later Malagasy orogeny at about 550–515 Mya affected Madagascar, eastern East Africa and southern India. In it, Neoproterozoic India collided with the already combined Azania and Congo–Tanzania–Bangweulu Block, at the same time, in the Kunga Orogeny Neoproterozoic India collided with the Australia/Mawson continent. Other large continental masses, including the core cratons of North America, Europe, when Pangaea broke up, two large masses, Gondwana and Laurasia, were formed. During the late Paleozoic, Gondwana extended from a point at or near the South Pole to near the Equator, across much of Gondwana, the climate was mild. During the Mesozoic, the world was on average warmer than it is today. Gondwana was then host to a variety of flora and fauna for many millions of years
4.
Mesozoic
–
The Mesozoic Era is an interval of geological time from about 252 to 66 million years ago. This Era is also called from a paleobotanist view the Age of Conifers, Mesozoic means middle life, deriving from the Greek prefix meso-/μεσο- for between and zōon/ζῷον meaning animal or living being. It is one of three eras of the Phanerozoic Eon, preceded by the Paleozoic and succeeded by the Cenozoic. The era is subdivided into three periods, the Triassic, Jurassic, and Cretaceous, which are further subdivided into a number of epochs. The Mesozoic was a time of significant tectonic, climate and evolutionary activity, the era witnessed the gradual rifting of the supercontinent Pangaea into separate landmasses that would eventually move into their current positions. The climate of the Mesozoic was varied, alternating between warming and cooling periods, overall, however, the Earth was hotter than it is today. Birds first appeared in the Jurassic, having evolved from a branch of theropod dinosaurs, the first mammals also appeared during the Mesozoic, but would remain small—less than 15 kg —until the Cenozoic. Following the Paleozoic, the Mesozoic extended roughly 186 million years and this time frame is separated into three geologic periods. It is also known as the Great Dying because it is considered the largest mass extinction in the Earths history, the upper boundary of the Mesozoic is set at the Cretaceous–Paleogene extinction event, which may have been caused by the impactor that created Chicxulub Crater on the Yucatán Peninsula. Towards the Late Cretaceous large volcanic eruptions are believed to have contributed to the Cretaceous–Paleogene extinction event. Approximately 50% of all genera became extinct, including all of the non-avian dinosaurs, the Triassic ranges roughly from 252 million to 201 million years ago. The Triassic is a time in Earths history bracketed between the Permian Extinction and the Triassic–Jurassic extinction event, two of the big five, and precedes the Jurassic Period and it has three major epochs, the Early Triassic, the Middle Triassic and the Late Triassic. The Early Triassic was between about 252 million to 247 million years ago and was dominated by deserts as Pangaea had not yet broken up, thus the interior was nothing, the Earth had just witnessed a massive die-off in which 95% of all life became extinct. The most common life on earth were Lystrosaurus, labyrinthodonts. Temnospondyls evolved during this time and would be the dominant predator for much of the Triassic, the Middle Triassic spans roughly from 247 million to 237 million years ago. The Middle Triassic featured the beginnings of the breakup of Pangaea, the ecosystem had recovered from the devastation that was the Great Dying. Algae, sponge, corals, and crustaceans all had recovered, new aquatic reptiles evolved, such as ichthyosaurs and nothosaurs. Meanwhile, on land, pine forests flourished, as did groups of insects like mosquitoes, the first ancient crocodilians evolved, which sparked competition with the large amphibians that had since ruled the freshwater world
5.
Indian Ocean
–
The Indian Ocean is the third largest of the worlds oceanic divisions, covering 70,560,000 km2. It is bounded by Asia on the north, on the west by Africa, on the east by Australia, the Indian Ocean is known as Ratnākara, the mine of gems in ancient Sanskrit literature, and as Hind Mahāsāgar, in Hindi. The northernmost extent of the Indian Ocean is approximately 30° north in the Persian Gulf, the oceans continental shelves are narrow, averaging 200 kilometres in width. An exception is found off Australias western coast, where the width exceeds 1,000 kilometres. The average depth of the ocean is 3,890 m and its deepest point is Diamantina Deep in Diamantina Trench, at 8,047 m deep, Sunda Trench has a depth of 7, 258–7,725 m. North of 50° south latitude, 86% of the basin is covered by pelagic sediments. The remaining 14% is layered with terrigenous sediments, glacial outwash dominates the extreme southern latitudes. The major choke points include Bab el Mandeb, Strait of Hormuz, the Lombok Strait, the Strait of Malacca, the Indian Ocean is artificially connected to the Mediterranean Sea through the Suez Canal, which is accessible via the Red Sea. All of the Indian Ocean is in the Eastern Hemisphere and the centre of the Eastern Hemisphere is in this ocean, marginal seas, gulfs, bays and straits of the Indian Ocean include, The climate north of the equator is affected by a monsoon climate. Strong north-east winds blow from October until April, from May until October south, in the Arabian Sea the violent Monsoon brings rain to the Indian subcontinent. In the southern hemisphere, the winds are milder. When the monsoon winds change, cyclones sometimes strike the shores of the Arabian Sea, the Indian Ocean is the warmest ocean in the world. Long-term ocean temperature records show a rapid, continuous warming in the Indian Ocean, Indian Ocean warming is the largest among the tropical oceans, and about 3 times faster than the warming observed in the Pacific. Research indicates that human induced greenhouse warming, and changes in the frequency, among the few large rivers flowing into the Indian Ocean are the Zambezi, Shatt al-Arab, Indus, Godavari, Krishna, Narmada, Ganges, Brahmaputra, Jubba and Irrawaddy River. The oceans currents are controlled by the monsoon. Two large gyres, one in the northern hemisphere flowing clockwise and one south of the equator moving anticlockwise, during the winter monsoon, however, currents in the north are reversed. Deep water circulation is controlled primarily by inflows from the Atlantic Ocean, the Red Sea, north of 20° south latitude the minimum surface temperature is 22 °C, exceeding 28 °C to the east. Southward of 40° south latitude, temperatures drop quickly, surface water salinity ranges from 32 to 37 parts per 1000, the highest occurring in the Arabian Sea and in a belt between southern Africa and south-western Australia
6.
Atlantic Ocean
–
The Atlantic Ocean is the second largest of the worlds oceans with a total area of about 106,460,000 square kilometres. It covers approximately 20 percent of the Earths surface and about 29 percent of its surface area. It separates the Old World from the New World, the Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Eurasia and Africa to the east, and the Americas to the west. The Equatorial Counter Current subdivides it into the North Atlantic Ocean, in contrast, the term Atlantic originally referred specifically to the Atlas Mountains in Morocco and the sea off the Strait of Gibraltar and the North African coast. The Greek word thalassa has been reused by scientists for the huge Panthalassa ocean that surrounded the supercontinent Pangaea hundreds of years ago. The term Aethiopian Ocean, derived from Ancient Ethiopia, was applied to the Southern Atlantic as late as the mid-19th century, many Irish or British people refer to the United States and Canada as across the pond, and vice versa. The Black Atlantic refers to the role of ocean in shaping black peoples history. Irish migration to the US is meant when the term The Green Atlantic is used, the term Red Atlantic has been used in reference to the Marxian concept of an Atlantic working class, as well as to the Atlantic experience of indigenous Americans. Correspondingly, the extent and number of oceans and seas varies, the Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea, Norwegian Sea, to the east, the boundaries of the ocean proper are Europe, the Strait of Gibraltar and Africa. In the southeast, the Atlantic merges into the Indian Ocean, the 20° East meridian, running south from Cape Agulhas to Antarctica defines its border. In the 1953 definition it extends south to Antarctica, while in later maps it is bounded at the 60° parallel by the Southern Ocean, the Atlantic has irregular coasts indented by numerous bays, gulfs, and seas. Including these marginal seas the coast line of the Atlantic measures 111,866 km compared to 135,663 km for the Pacific. Including its marginal seas, the Atlantic covers an area of 106,460,000 km2 or 23. 5% of the ocean and has a volume of 310,410,900 km3 or 23. 3%. Excluding its marginal seas, the Atlantic covers 81,760,000 km2 and has a volume of 305,811,900 km3, the North Atlantic covers 41,490,000 km2 and the South Atlantic 40,270,000 km2. The average depth is 3,646 m and the maximum depth, the bathymetry of the Atlantic is dominated by a submarine mountain range called the Mid-Atlantic Ridge. It runs from 87°N or 300 km south of the North Pole to the subantarctic Bouvet Island at 42°S, the MAR divides the Atlantic longitudinally into two halves, in each of which a series of basins are delimited by secondary, transverse ridges. The MAR reaches above 2000 m along most of its length, the MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the other
7.
Cretaceous
–
The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago to the beginning of the Paleogene Period 66 Mya. It is the last period of the Mesozoic Era, the Cretaceous Period is usually abbreviated K, for its German translation Kreide. The Cretaceous was a period with a warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites and rudists, during this time, new groups of mammals and birds, as well as flowering plants, appeared. The Cretaceous ended with a mass extinction, the Cretaceous–Paleogene extinction event, in which many groups, including non-avian dinosaurs, pterosaurs. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary, the name Cretaceous was derived from Latin creta, meaning chalk. The Cretaceous is divided into Early and Late Cretaceous epochs, or Lower and Upper Cretaceous series, in older literature the Cretaceous is sometimes divided into three series, Neocomian, Gallic and Senonian. A subdivision in eleven stages, all originating from European stratigraphy, is now used worldwide, in many parts of the world, alternative local subdivisions are still in use. As with other geologic periods, the rock beds of the Cretaceous are well identified. No great extinction or burst of diversity separates the Cretaceous from the Jurassic and this layer has been dated at 66.043 Ma. A140 Ma age for the Jurassic-Cretaceous boundary instead of the usually accepted 145 Ma was proposed in 2014 based on a study of Vaca Muerta Formation in Neuquén Basin. Víctor Ramos, one of the authors of the study proposing the 140 Ma boundary age sees the study as a first step toward formally changing the age in the International Union of Geological Sciences, due to the high sea level there was extensive space for such sedimentation. Because of the young age and great thickness of the system. Chalk is a type characteristic for the Cretaceous. It consists of coccoliths, microscopically small calcite skeletons of coccolithophores, the group is found in England, northern France, the low countries, northern Germany, Denmark and in the subsurface of the southern part of the North Sea. Chalk is not easily consolidated and the Chalk Group still consists of sediments in many places. The group also has other limestones and arenites, among the fossils it contains are sea urchins, belemnites, ammonites and sea reptiles such as Mosasaurus. In southern Europe, the Cretaceous is usually a marine system consisting of competent limestone beds or incompetent marls
8.
Tethys (mythology)
–
In Greek mythology, Tethys, was a Titan daughter of Uranus and Gaia, and the wife of her brother the Titan-god Oceanus, and the mother by him of the river gods and the Oceanids. Tethys had no role in Greek mythology, and no established cults. Tethys was one of the Titan offspring of Uranus and Gaia, Hesiod lists her Titan syblings as Oceanus, Coeus, Crius, Hyperion, Iapetus, Theia, Rhea, Themis, Mnemosyne, Phoebe, and Cronus. Tethys married her brother, Oceanus, an enormous river encircling the world, and was, by him, the mother of sons, who were river-gods. According to Hesiod, there were three thousand river-gods, also according to Hesiod, there were three thousand Oceanids. Passages in a section of the Iliad called the Deception of Zeus, suggest the possibility that Homer knew a tradition in which Oceanus and Tethys were the parents of the Titans. Twice Homer has Hera describe the pair as Oceanus, from whom the gods are sprung, however, for M. L. West, these lines suggests a myth in which Oceanus and Tethys are the first parents of the whole race of gods. Tethys played no part in Greek mythology, the only early story concerning Tethys, is what Homer has Hera briefly relate in the Iliads Deception of Zeus passage. Hera relates this while dissembling that she is on her way to visit Oceanus and Tethys, in hopes of reconciling her foster parents, who angry with each other, are no longer having sexual relations. Originally Oceanus consort, at a later time Tethys came to be identified with the sea, in Ovids Metamorphoses, Tethys turns Aesacus into a diving bird. Tethys was sometimes confused with another sea goddess, the sea-nymph Thetis and this possible correspondence between Oceanus and Tethys, and Apsū and Tiamat, has been noticed by several authors, with Tethys name possibly having been derived from that of Tiamat. Representations of Tethys prior to the Roman period are rare, Tethys appears, identified by inscription, as part of an illustration of the wedding of Peleus and Thetis on the early sixth century BC Attic black-figure Erskine dinos by Sophilos. Tethys, accompanied by Eileithyia, the goddess of childbirth, follows close behind Oceanus, Tethys is also conjectured to be represented in a similar illustration of the wedding of Peleus and Thetis depicted on the early sixth century BC Attic black-figure François Vase. Tethys probably also appeared as one of the fighting the Giants in the Gigantomachy frieze of the second century BC Pergamon Altar. Only fragments of the figure remain, a part of a chiton, below Oceanus left arm, the above are the only artistic representations of Tethys known prior to the Roman period. Her identifying attributes are wings sprouting from her forehead, a rudder/oar, and a ketos, a creature from Greek mythology with the head of a dragon and the body of a snake. The earliest of these mosaics, identified as Tethys, decorated a triclinium overlooking a pool, excavated from the House of the Calendar in Antioch, dated to shortly after AD115. Tethys, reclining on the left, with Oceanus reclining on the right, has long hair, a ketos twines around her raised right arm
9.
Oceanus
–
Strictly speaking, Oceanus was the ocean-stream at the Equator in which floated the habitable hemisphere. Thus, the sun rises from the deep-flowing Oceanus in the east, in Greek mythology, this world-ocean was personified as a Titan, the eldest son of Uranus and Gaia. In Hellenistic and Roman mosaics, this Titan was often depicted as having the body of a muscular man with a long beard and horns. In Roman mosaics, such as that from Bardo he might carry a steering-oar, some scholars believe that Oceanus originally represented all bodies of salt water, including the Mediterranean Sea and the Atlantic Ocean, the two largest bodies known to the ancient Greeks. Oceanus consort is his sister Tethys, and from their union came the ocean nymphs, also referred to as the three-thousand Oceanids, and all the rivers of the world, fountains, and lakes. In most variations of this myth, Oceanus also refused to side with Cronus in the revolt against their father. R. S. P. Beekes has suggested a Pre-Greek proto-form *-kay-an-, when Odysseus and Nestor walk together along the shore of the sounding sea they address their prayers to the great Sea-god who girdles the world. It is to Oceanus, not to Poseidon, that their thoughts are directed, Heracles forced Helios to lend him his golden bowl, in order to cross the wide expanse of the Ocean on his trip to the Hesperides. When Oceanus tossed the bowl about, Heracles threatened him and stilled his waves, the journey of Heracles in the sun-bowl upon Oceanus became a favored theme among painters of Attic pottery. Oceanus appears in Hellenic cosmography as well as myth, cartographers continued to represent the encircling equatorial stream much as it had appeared on Achilles shield. Apollonius of Rhodes calls the lower Danube the Keras Okeanoio in Argonautica, accion in the fourth century Gaulish Latin of Rufus Avienus, Ora maritima, was applied to great lakes. At the end of the Okeanos Potamos, is the island of Alba, sacred to the Pelasgian Apollo. Hecateus of Abdera refers to Apollos island from the region of the Hyperboreans and it was on Leuke, in one version of his legend, that the hero Achilles, in a hilly tumulus, was buried. Leto, the Hyperborean goddess, after nine days and nine nights of labour on the island of Delos gave birth to the god of the antique light. Old Romanian folk songs sing of a monastery on a white island with nine priests, nine singers, nine altars. Oceanid Ogyges Rasā Uranus Aeschylus, Persians, edited and translated by Alan H. Sommerstein. Cambridge, MA, Harvard University Press,2009, online version at Harvard University Press. Apollodorus, Apollodorus, The Library, with an English Translation by Sir James George Frazer, Cambridge, MA, Harvard University Press, London, William Heinemann Ltd.1921
Media related to Tethys Ocean at Wikimedia Commons
