Geological Society of America
The Geological Society of America is a nonprofit organization dedicated to the advancement of the geosciences. The society was founded in New York in 1888 by Alexander Winchell, John J. Stevenson, Charles H. Hitchcock and Edward Orton and has been headquartered at 3300 Penrose Place, Colorado, USA, since 1968. The society has six sections in North America, an international section. GSA began with 100 members under its first president, James Hall, over the next 43 years it grew slowly but steadily to 600 members until 1931, when a $4 million endowment from 1930 president R. A. F. Penrose, Jr. jumpstarted the GSAs growth, as of April 2013, GSA has more than 25,000 members in over 100 countries. The stated mission of GSA is to advance research and discovery, service to society, stewardship of Earth. Its main activities are sponsoring scientific meetings and publishing scientific literature, particularly the journals Geological Society of America Bulletin, a more recent publication endeavor is the online-only journal Geosphere.
In February 2009, GSA began publishing Lithosphere, GSAs monthly news and science magazine, GSA Today, is open access online. Furthermore, the implications of global climate change and the time scale over which such changes will likely occur require active, effective. While the precise magnitude and rate of change cannot be predicted with absolute certainty, significant change will affect the planet. Past presidents of the Geological Society of America, American Geophysical Union Penrose Medal Arthur L. Day Medal Meinzer Award Kirk Bryan Award GSA Official Website
A mid-ocean ridge is an underwater mountain system formed by plate tectonics. It consists of various mountains linked in chains, typically having a known as a rift running along its spine. This type of mountain ridge is characteristic of what is known as an oceanic spreading center. The production of new results from mantle upwelling in response to plate spreading. The buoyant melt rises as magma at a linear weakness in the oceanic crust, a mid-ocean ridge demarcates the boundary between two tectonic plates, and consequently is termed a divergent plate boundary. Mid-ocean ridges are geologically active, with new magma constantly emerging onto the floor and into the crust at. The crystallized magma forms new crust of basalt and gabbro and they are formed by two oceanic plates moving away from each other. The rocks making up the crust below the seafloor are youngest along the axis of the ridge and age with increasing distance from that axis, new magma of basalt composition emerges at and near the axis because of decompression melting in the underlying Earths mantle.
The oceanic crust is made up of much younger than the Earth itself. Most oceanic crust in the basins is less than 200 million years old. The crust is in a constant state of renewal at the ocean ridges, moving away from the mid-ocean ridge, ocean depth progressively increases, the greatest depths are in ocean trenches. As the oceanic crust moves away from the axis, the peridotite in the underlying mantle cools. The crust and the relatively rigid peridotite below it make up the oceanic lithosphere, by contrast, fast spreading ridges like the East Pacific Rise are narrow, sharp incisions surrounded by generally flat topography that slopes away from the ridge over many hundreds of miles. The overall shape of ridges results from Pratt isostacy, close to the ridge there is hot. As the oceanic plates cool, away from the axes, the oceanic mantle lithosphere thickens. Thus older seafloor is underlain by denser material and sits lower, there are two processes, ridge-push and slab pull, thought to be responsible for the spreading seen at mid-ocean ridges, and there is some uncertainty as to which is dominant.
Ridge-push occurs when the bulk of the ridge pushes the rest of the tectonic plate away from the ridge. At the subduction zone, slab-pull comes into effect and this is simply the weight of the tectonic plate being subducted below the overlying plate dragging the rest of the plate along behind it
Baltica was a late-Proterozoic, early-Palaeozoic continent that now includes the East European craton of northwestern Eurasia. Baltica was created as an entity not earlier than 1.8 billion years ago, before this time, the three segments/continents that now compose the East European craton were in different places on the globe. Baltica existed on a plate called the Baltic Plate. ~1.82 billion years ago, Baltica was part of the major supercontinent Columbia, ~1.5 billion years ago, Baltica along with Arctica and East Antarctica were part of the minor supercontinent Nena. ~1.07 billion years ago, Baltica was part of the major supercontinent Rodinia, ~750 million years ago, Baltica was part of the minor supercontinent Protolaurasia. ~600 million years ago, Baltica was part of the major supercontinent Pannotia, ~Cambrian, Baltica was an independent continent. ~Late Ordovician, Baltica collided with Avalonia ~Devonian, Baltica collided against Laurentia, ~Permian, all major continents collided against each other to form the major supercontinent Pangaea.
~Jurassic, Pangaea rifted into two supercontinents and Gondwana. Baltica was part of the minor supercontinent Laurasia, ~Cretaceous, Baltica was part of the minor supercontinent Eurasia. ~Present, Baltica is part of the minor supercontinent Afro-Eurasia. Around 250 million years from now, all continents may crash together, Baltica would be part of Pangaea Proxima. Around 450-600 Ma from now, Pangea Proxima will eventually rift apart
In geology, a rift is a linear zone where the Earths crust and lithosphere are being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting, where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the area may contain volcanic rocks, and active volcanism is a part of many. Major rifts occur along the axis of most mid-ocean ridges. Failed rifts are the result of rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a junction where three converging rifts meet over a hotspot. Two of these evolve to the point of spreading, while the third ultimately fails. Most rifts consist of a series of segments that together form the linear zone characteristic of rifts. The individual rift segments have a dominantly half-graben geometry, controlled by a single basin-bounding fault, segment lengths vary between rifts, depending on the elastic thickness of the lithosphere.
Areas of thick colder lithosphere, such as the Baikal Rift have segment lengths in excess of 80 km, while in areas of warmer thin lithosphere, segment lengths may be less than 30 km. Along the axis of the rift the position, and in cases the polarity. Segment boundaries often have a complex structure and generally cross the rift axis at a high angle. These segment boundary zones accommodate the differences in fault displacement between the segments and are known as accommodation zones. Accommodation zones may be located where older crustal structures intersect the rift axis, in the Gulf of Suez rift, the Zaafarana accommodation zone is located where a shear zone in the Arabian-Nubian Shield meets the rift. At the onset of rifting, the part of the lithosphere starts to extend on a series of initially unconnected normal faults. In subaerial rifts, drainage at this stage is generally internal, as the rift evolves, some of the individual fault segments grow, eventually becoming linked together to form the larger bounding faults.
Subsequent extension becomes concentrated on these faults, the longer faults and wider fault spacing leads to more continuous areas of fault-related subsidence along the rift axis. Significant uplift of the rift shoulders develops at this stage, strongly influencing drainage, during rifting, as the crust is thinned, the Earths surface subsides and the Moho becomes correspondingly raised
Rhea is the Titaness daughter of the earth goddess Gaia and the sky god Uranus, in Greek mythology and sister and wife to Cronus. In early traditions, she is known as the mother of gods and therefore is associated with Gaia and Cybele. The classical Greeks saw her as the mother of the Olympian gods and goddesses, the Romans identified her with Magna Mater, and the Goddess Ops. Alternatively, the name Rhea may be connected with words for the pomegranate, ῥόα, the name Rhea may ultimately derive from a pre-Greek or Minoan source. Cronus sired six children by Rhea, Hades, Poseidon and Zeus in that order. Apart from Zeus, he swallowed all as soon as they were born, because he had learned from Gaia and Uranus that, as he had overthrown his own father, he was destined to be overcome by his own child. When Zeus was about to be born, Rhea sought Uranus and Gaia to devise a plan to him, so that Cronus would get his retribution for his acts against Uranus. Rhea gave birth to Zeus in Crete, and saved him by handing Cronus a stone wrapped in swaddling clothes, Rhea hid Zeus in a cave on Mount Ida in Crete.
Her attendants, the warrior-like Curetes and Dactyls, acted as a bodyguard for the infant Zeus, Rhea had no strong local cult or identifiable activity under her control. She was originally worshiped in the island of Crete, identified in mythology as the site of Zeuss infancy and her cults employed rhythmic, raucous chants and dances, accompanied by the tympanon, to provoke a religious ecstasy. Her priests impersonated her mythical attendants, the Curetes and Dactyls, with a clashing of bronze shields, in Roman religion, her counterpart Cybele was Magna Mater deorum Idaea, who was brought to Rome and was identified in Roman mythology as an ancestral Trojan deity. On a functional level, Rhea was thought equivalent to Roman Ops or Opis, the one at Mycenae is most characteristic, with a lioness placed on either side of a pillar that symbolizes the goddess. In Homer, Rhea is the mother of the gods, although not a mother like Cybele. In the Argonautica by Apollonius of Rhodes, the fusion of Rhea, for her temenos they wrought an image of the goddess, a xoanon, from a vine-stump.
They leapt and danced in their armour, For this reason the Phrygians still worship Rhea with tambourines, the name of the bird species rhea is derived from the goddess name Rhea. The second largest moon of the planet Saturn is named after her, Timothy, Early Greek Myth, A Guide to Literary and Artistic Sources, Johns Hopkins University Press,1996, Two volumes, ISBN 978-0-8018-5360-9, ISBN 978-0-8018-5362-3. Hesiod, Theogony, in The Homeric Hymns and Homerica with an English Translation by Hugh G. Evelyn-White, harvard University Press, William Heinemann Ltd.1914. Online version at the Perseus Digital Library, The Iliad with an English Translation by A. T
Subduction is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another and is forced or sinks due to gravity into the mantle. Regions where this occurs are known as subduction zones. Rates of subduction are typically in centimeters per year, with the rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Plates include both oceanic crust and continental crust, stable subduction zones involve the oceanic lithosphere of one plate sliding beneath the continental or oceanic lithosphere of another plate due to the higher density of the oceanic lithosphere. That is, the lithosphere is always oceanic while the overriding lithosphere may or may not be oceanic. Subduction zones are sites that have a rate of volcanism, earthquakes. Subduction zones are sites of convective downwelling of Earths lithosphere, subduction zones exist at convergent plate boundaries where one plate of oceanic lithosphere converges with another plate.
The descending slab, the plate, is over-ridden by the leading edge of the other plate. The slab sinks at an angle of approximately twenty-five to forty-five degrees to Earths surface and this sinking is driven by the temperature difference between the subducting oceanic lithosphere and the surrounding mantle asthenosphere, as the colder oceanic lithosphere is, on average, denser. At a depth of approximately 80–120 kilometers, the basalt of the oceanic crust is converted to a rock called eclogite. At that point, the density of the oceanic crust increases and provides additional negative buoyancy and it is at subduction zones that Earths lithosphere, oceanic crust, sedimentary layers and some trapped water are recycled into the deep mantle. Earth is so far the only planet where subduction is known to occur, subduction is the driving force behind plate tectonics, and without it, plate tectonics could not occur. Subduction zones dive down into the mantle beneath 55,000 kilometers of convergent plate margins, subduction zones burrow deeply but are imperfectly camouflaged, and geophysics and geochemistry can be used to study them.
Not surprisingly, the shallowest portions of subduction zones are known best, subduction zones are strongly asymmetric for the first several hundred kilometers of their descent. They start to go down at oceanic trenches and their descents are marked by inclined zones of earthquakes that dip away from the trench beneath the volcanoes and extend down to the 660-kilometer discontinuity. Subduction zones are defined by the array of earthquakes known as the Wadati–Benioff zone after the two scientists who first identified this distinctive aspect. Subduction zone earthquakes occur at greater depths than elsewhere on Earth, such deep earthquakes may be driven by deep phase transformations, thermal runaway, the subducting basalt and sediment are normally rich in hydrous minerals and clays. Additionally, large quantities of water are introduced into cracks and fractures created as the slab bends downward
The Alleghanian orogeny or Appalachian orogeny is one of the geological mountain-forming events that formed the Appalachian Mountains and Allegheny Mountains. The term and spelling Alleghany orogeny was originally proposed by H. P, the Alleghanian orogeny occurred approximately 325 million to 260 million years ago over at least five deformation events in the Carboniferous to Permian period. The orogeny was caused by Africa colliding with North America, at the time, these continents did not exist in their current forms, North America was part of the Euramerica super-continent, while Africa was part of Gondwana. This collision formed the super-continent Pangaea, which contained all major land masses. The collision provoked the orogeny, it exerted massive stress on what is today the Eastern Seaboard of North America, forming a wide and high mountain chain. Evidence for the Alleghanian orogeny stretches for hundreds of miles on the surface from Alabama to New Jersey. In the north, the Alleghanian deformation extends northeast to Newfoundland, subsequent erosion wore down the mountain chain and spread sediments both to the east and to the west.
As the continents collided, the rock material trapped in-between was crushed and forced upward, with nowhere to go, rocks along the eastern margin of the North American continent were shoved far inland. Close to the boundary between the plates, tectonic stresses contributed to the metamorphism of the rock. The sedimentary rock in the eastern Appalachian Basin region was squeezed into great folds that ran perpendicular to the direction of forces, the greatest amount of deformation associated with the Alleghanian orogeny occurred in the Southern Appalachians. In that region, a series of great faults developed in addition to the folds, the relative amount of deformation gradually diminishes as one travels northward. The fold belt extends northward through Pennsylvania and gradually fades in the vicinity of the New York border, the Kittatinny Mountains in northwestern New Jersey mark the Northeastern-most extension of the high ridges of the Valley and Ridge Province. The influence of Alleghanian deformation on the regions east of the Valley and Ridge Province must have even more intense, however.
Rocks of Mississippian and Permian age are missing along the Eastern Seaboard, the mountains formed by the Alleghanian orogeny were once rugged and high, but in our time are now eroded into only a small remnant, the heavily-eroded hills of the Piedmont. Sediments that were carried eastward formed the coastal plain and part of the continental shelf, the coastal plain and Piedmont are largely the byproducts of erosion that took place from 150+ million years ago to the present. Sediments that were carried westward formed the Allegheny and Cumberland Plateau, which in some areas are popularly called mountains, a portion of the Alleghanian mountain system departed with Africa when Pangaea broke up and the Atlantic Ocean began to form. Today, this forms the Anti-Atlas mountains of Morocco, the Anti-Atlas have been geologically uplifted in relatively recent times, and are today much more rugged than their Alleghanian relatives. Geology of the Appalachians Central Pangean Mountains Mauritanide Belt Inliers and outliers
In Greek mythology, Atlas was a Titan condemned to hold up the sky for eternity after the Titanomachy. Although associated with places, he became commonly identified with the Atlas Mountains in northwest Africa. Atlas was the son of the Titan Iapetus and the Oceanid Asia or Clymene and he had many children, mostly daughters, the Hesperides, the Hyades, the Pleiades, and the nymph Calypso who lived on the island Ogygia. According to the ancient Greek poet Hesiod Atlas stood at the ends of the earth towards the west, according to Robert Gravess The Greek Myths, the Pelasgians believed the creator goddess Eurynome assigned Atlas and Phoebe to govern the moon. Hyginus emphasises the nature of Atlas by making him the son of Aether. Atlantic Ocean means Sea of Atlas, while Atlantis means island of Atlas, the etymology of the name Atlas is uncertain. Since the Atlas mountains rise in the inhabited by Berbers, it has been suggested that the name might be taken from one of the Berber. However, Robert Beekes argues that it cannot be expected that this ancient Titan carries an Indo-European name, and that the word is of Pre-Greek origin and his brother Menoetius sided with the Titans in their war against the Olympians, the Titanomachy.
Thus, he was Atlas Telamon, enduring Atlas, and became a doublet of Coeus, in a late story, a giant named Atlas tried to drive a wandering Perseus from the place where the Atlas mountains now stand. According to Plato, the first king of Atlantis was named Atlas, but that Atlas was a son of Poseidon, a euhemerist origin for Atlas was as a legendary Atlas, king of Mauretania, an expert astronomer. One of the Twelve Labors of the hero Heracles was to some of the golden apples which grow in Heras garden, tended by Atlas daughters, the Hesperides. Heracles went to Atlas and offered to hold up the heavens while Atlas got the apples from his daughters, when Atlas set down the apples and took the heavens upon his shoulders again, Heracles took the apples and ran away. In some versions, Heracles instead built the two great Pillars of Hercules to hold the sky away from the earth, liberating Atlas much as he liberated Prometheus. The identifying name Aril is inscribed on two 5th-century Etruscan bronze items, a mirror from Vulci and a ring from an unknown site, the Etruscan name aril is etymologically independent.
Sources describe Atlas as the father, by different goddesses, of numerous children, some of these are assigned conflicting or overlapping identities or parentage in different sources. By Hesperius, the Hesperides By Pleione, the Hyades a son, Hyas the Pleiades By one or more unspecified goddesses, ISBN 0-14-001026-2 Smith, Dictionary of Greek and Roman Biography and Mythology, London
Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate. The crust overlies the solidified and uppermost layer of the mantle, the crust and the solid mantle layer together constitute oceanic lithosphere. Oceanic crust is the result of erupted mantle material originating from below the plate, cooled and in most instances and this occurs mostly at mid-ocean ridges, but at scattered hotspots, and in rare but powerful occurrences known as flood basalt eruptions. It is primarily composed of rocks, or sima, which is rich in iron. Although a complete section of oceanic crust has not yet been drilled, Oceanic crust is significantly simpler than continental crust and generally can be divided in three layers. Layer 1 is on an average 0.4 km thick and it consists of unconsolidated or semiconsolidated sediments, usually thin or even not present near the mid-ocean ridges but thickens farther away from the ridge. Layer 3 is formed by slow cooling of magma beneath the surface and consists of coarse grained gabbros and it constitutes over two-thirds of oceanic crust volume with almost 5 km thickness.
The most voluminous volcanic rocks of the floor are the mid-oceanic ridge basalts. These rocks have low concentrations of large ion lithophile elements, light rare earth elements, volatile elements, there can be found basalts enriched with incompatible elements, but they are rare and associated with mid-ocean ridge hot spots such as surroundings of Galapagos Islands, the Azores and Iceland. Oceanic crust is continuously being created at mid-ocean ridges, as plates diverge at these ridges, magma rises into the upper mantle and crust. As it moves away from the ridge, the lithosphere becomes cooler and denser, the youngest oceanic lithosphere is at the oceanic ridges, and it gets progressively older away from the ridges. As the mantle rises it cools and melts, as the pressure decreases, the amount of melt produced depends only on the temperature of the mantle as it rises. Hence most oceanic crust is the same thickness, an example of this is the Gakkel Ridge under the Arctic Ocean. Thicker than average crust is found above plumes as the mantle is hotter and hence it crosses the solidus and melts at a depth, creating more melt.
An example of this is Iceland which has crust of thickness ~20 km, the oceanic lithosphere subducts at what are known as convergent boundaries. These boundaries can exist between oceanic lithosphere on one plate and oceanic lithosphere on another, or between oceanic lithosphere on one plate and continental lithosphere on another, in the second situation, the oceanic lithosphere always subducts because the continental lithosphere is less dense. The subduction process consumes older oceanic lithosphere, so oceanic crust is more than 200 million years old. The process of super-continent formation and destruction via repeated cycles of creation and destruction of oceanic crust is known as the Wilson cycle, the oldest large scale oceanic crust is in the west Pacific and north-west Atlantic - both are about up to 180-200 million years old
The Iapetus Ocean was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale. The Iapetus Ocean was situated in the hemisphere, between the paleocontinents of Laurentia and Avalonia. The ocean disappeared with the Acadian and Taconic orogenies, the southern Iapetus Ocean has been proposed to have closed with the Famatinian and Taconic orogenies, meaning a collision between Western Gondwana and Laurentia. The Iapetus Ocean was therefore named for the titan Iapetus, who in Greek mythology was the father of Atlas, after whom the Atlantic Ocean was named. Geologists of the early 20th century presumed that a large trough, with the development of plate tectonics in the 1960s, geologists such as Arthur Holmes and John Tuzo Wilson concluded that the Atlantic Ocean must have had a precursor before the time of Pangaea. Wilson noticed that the Atlantic had opened at roughly the place where its precursor ocean had closed. This led him to his Wilson cycle hypothesis, in many spots in Scandinavia basaltic dikes are found with ages between 670 and 650 million years.
These are interpreted as evidence that by that time, rifting had started that would form the Iapetus Ocean, in Newfoundland and Labrador, the Long Range dikes are thought to have formed during the formation of the Iapetus Ocean. The southern Iapetus Ocean opened between Laurentia and southwestern Gondwana about 550 Ma in the Ediacaran–Cambrian transition, at the time it did so the Adamastor Ocean further east closed. However, the formation of both oceans seems unrelated, southwest of the Iapetus, a volcanic island arc evolved from the early Cambrian onward. This volcanic arc was formed above a subduction zone where the lithosphere of the Iapetus Ocean subducted southward under other oceanic lithosphere. From Cambrian times the western Iapetus Ocean began to grow progressively narrower due to this subduction, the same happened further north and east, where Avalonia and Baltica began to move towards Laurentia from the Ordovician onward. In the west, the Iapetus Ocean closed with the Taconic orogeny, some authors consider the oceanic basin south of the island arc a part of the Iapetus, this branch closed during the Acadian orogeny, when Avalonia collided with Laurentia.
It has been suggested that the southern Iapetus Ocean closed during a collision between Laurentia and Western Gondwana. If factual the Taconic orogen would be the continuation of the Famatinian orogen exposed in Argentina. Avalonia Baltica Geologic timescale Khanty Ocean London-Brabant Massif Plate tectonics Southern uplands of Scotland Cocks, L. R. N. Fortey, Biogeography of Ordovician and Silurian faunas. In McKerrow, W. S. Scotese, C. F. Palaeozoic Palaeogeography and Biogeography, dalziel, I. W. Neoproterozoic-Paleozoic geography and tectonics, hypothesis, environmental speculation. 1972, The Arctic Caledonides and earlier oceans, Geological Magazine 109,2003, The making and unmaking of a supercontinent, Rodinia revisited, Tectonophysics 375, pp. 261–288
The Ouachita orogeny was a mountain building event that resulted in the folding and faulting of strata currently exposed in the Ouachita Mountains. The region during the early Paleozoic lay off the coast of the portion of Laurentia. Laurentia straddled the equator at the time and the Rheic Ocean was to the south of Laurentia, through the Ordovician, Silurian and early Carboniferous, marine sedimentation left extensive deposits of black shale, quartzose sandstone, and chert beds. During the Mississippian, a sequence with dark shales and graywackes was deposited. Lenses of silicic tuff exist as evidence of limited volcanism and these sediments were formed over a subduction zone which formed along southern Laurentia. South America approached Laurentia as the oceanic crust was subducted. The collision of South American and Laurentian continental crust compressed and uplifted the region to form the Ouachita Mountains, during the Pennsylvanian and Permian, river systems draining westward from the Ouachita Mountains deposited sediments in north-central Texas and Oklahoma, which are now exposed at the surface.
The structures there have only been revealed through deep drilling in petroleum exploration
An ocean is a body of saline water that composes much of a planets hydrosphere. On Earth, an ocean is one of the major divisions of the World Ocean. These are, in descending order by area, the Pacific, Indian, the word sea is often used interchangeably with ocean in American English but, strictly speaking, a sea is a body of saline water partly or fully enclosed by land. The ocean contains 97% of Earths water, and oceanographers have stated that less than 5% of the World Ocean has been explored, the total volume is approximately 1.35 billion cubic kilometers with an average depth of nearly 3,700 meters. As the world ocean is the component of Earths hydrosphere, it is integral to all known life, forms part of the carbon cycle. The world ocean is the habitat of 230,000 known species, but because much of it is unexplored, the origin of Earths oceans remains unknown, oceans are thought to have formed in the Hadean period and may have been the impetus for the emergence of life. Extraterrestrial oceans may be composed of water or other elements and compounds, the only confirmed large stable bodies of extraterrestrial surface liquids are the lakes of Titan, although there is evidence for the existence of oceans elsewhere in the Solar System.
Early in their histories and Venus are theorized to have had large water oceans. The Mars ocean hypothesis suggests that nearly a third of the surface of Mars was once covered by water, compounds such as salts and ammonia dissolved in water lower its freezing point so that water might exist in large quantities in extraterrestrial environments as brine or convecting ice. Unconfirmed oceans are speculated beneath the surface of many planets and natural satellites, notably. The Solar Systems giant planets are thought to have liquid atmospheric layers of yet to be confirmed compositions. Oceans may exist on exoplanets and exomoons, including surface oceans of water within a circumstellar habitable zone. Ocean planets are a type of planet with a surface completely covered with liquid. The concept of Ōkeanós has an Indo-European connection, Greek Ōkeanós has been compared to the Vedic epithet ā-śáyāna-, predicated of the dragon Vṛtra-, who captured the cows/rivers. Related to this notion, the Okeanos is represented with a dragon-tail on some early Greek vases, though generally described as several separate oceans, these waters comprise one global, interconnected body of salt water sometimes referred to as the World Ocean or global ocean.
This concept of a body of water with relatively free interchange among its parts is of fundamental importance to oceanography. The major oceanic divisions – listed below in descending order of area and volume – are defined in part by the continents, various archipelagos, Oceans are fringed by smaller, adjoining bodies of water such as seas, bays and straits. The Mid-Oceanic Ridge of the World are connected and form the Ocean Ridge, the continuous mountain range is 65,000 km long, and the total length of the oceanic ridge system is 80,000 km long