How did the submarine canyons of the continental slope originate?
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Eons ago there were rivers\n\nTh
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This process is known as plate tectonics. The earth's surface is composed of large 'plates' which gradually move around over time. The movement is driven by convective currents of molten rock within the asthenosphere. Movement begins at the midocean ridges, which are actually larger than continental mountain ranges. As magma builds these ridges the weight of the material, combined with the convective flow causes them to push outward towards the outer parts of the oceanic plates. Some of these plates subduct (go under) the continental plates, or even other oceanic plates. This subduction process lifts continents higher and leads to mountain building. You can see some illustrations here:\nhttp://www.ucmp.berkeley.edu/geology/tecmech.html\nYou can watch animated versions showing the plate motion here:\nhttp://www.ucmp.berkeley.edu/geology/tecmech.html\n\nAs for parts of the earth falling into the ocean, that is just a not-so-serious thing that people say trying to explain plate tectonics. There are zones of continental crust that are rifting, being split apart, and these may eventually move below sea level. Some examples of this are the Great Rift Basin in northern Africa. The Red Sea is a rift zone that has submerged, and the Dead Sea is part of a rift zone. \n\nThese processes are quite slow on our time scale. The Pacific Ocean is spreading about 4-5 cm per year.\n\nAnd if you've ever heard that California is going to fall into the ocean- don't worry it isn't. The boundary between the Pacific Plate and the North American plate is actually within California, but the motion is such that Los Angeles is moving north towards San Francisco. Millions of years from now, Los Angeles may be moved north of San Francisco.
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The Atlantic Ocean is 150-135 million years old.\n\n~~~~~\n~180 Million Years Ago~\nThe supercontinent Pangea began to break up into two continents, Laurasia and Gondwanaland. Laurasia was made of the present day continents of North America (Greenland), Europe, and Asia. Gondwanaland was made of the present day continents of Antarctica, Australia, South America.\n\nScientists believe that Pangea broke apart for the same reason that the plates are moving today. The movement is caused by the convection currents that roll over in the upper zone of the mantle. This movement in the mantle causes the plates to move slowly across the surface of the Earth.\n\nThe huge world-ocean called Panthalassa remained but the Atlantic Ocean was going to be born soon with the splitting of North America from the Eurasian Plate. \n\n~150-135 Million Years Ago~\n150 to 135 million years ago Laurasia was on the move, and as it moved it broke up into the continents of North America, Europe and Asia (Eurasian plate). \n\nGondwanaland was spread apart, too, and it broke up into the continents of Africa, Antarctica, Australia, South America, and the subcontinent of India. \n\nArabia started to separate from Africa as the Red Sea opened up.\n\nThe Atlantic, Indian, Arctic, and Pacific Oceans were beginning to take shape as the continents move toward their present positions. \n\n\n~The Atlantic Ocean~\nThe Atlantic began to form about 150 million years ago, during the Jurassic period, when a rift opened up in the supercontinent of Gondwanaland, resulting in the separation of South America and Africa. \n\nThe separation continues today at the rate of several centimeters a year along the Mid-Atlantic Ridge. Part of the midoceanic ridge system that girdles the world, it is a submarine ridge extending north to south in a sinuous path midway between the continents. \n\nRoughly 930 miles wide, the ridge has a more rugged topography than any mountain range on land, and is a frequent site of volcanic eruptions and earthquakes. The ridge ranges from 1/2 to 2 miles above the ocean bottom.\n\nThe Atlantic Ocean is the second youngest of the world's oceans, after the Southern Ocean.
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Glaciers cannot move across entire oceans.  Large continental ice sheets that grow large enough to intersect a coastline sometimes extend into the ocean (see #1 below).  Their base sits on the seafloor, and in some cases can extend hundreds of miles out to sea.  The West Antarctic Ice Sheet is a continental glacier that is 'grounded' below sea level.  It sits on the continental shelf of the Ross Sea.  In the past (several thousands of years ago), it extended all the way to the edge of the continental shelf.\n\nThese glaciers also usually have whats is called an ice shelf.  An ice shelf is an extension of the glacier that floats on the ocean.  Icebergs are a product of bits of the ice shelf breaking off into the ocean.  Ice shelves can extend several hundreds of miles into the ocean (see #2).\n\nValley glaciers in places like Alaska or Greenland also discharge into the ocean.  The ends of these glaciers typically float and extend out into the bay of the valley where the glacier sits.
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City Map/Atlas\nPolitical Map\n\nThe Grand Canyon was created by the erosion of the Colorado river aided by wind, rain, ice, and gravity.
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I'm going to assume you are asking about deposition of rock, but am unsure because this is under 'other' and not earth science. \n\nDeposition of rock in the marine environment occurs in at least three ways. The first is by transport, which can be by wind, water, gravity, or ice. Water from rivers carries sediment into ocean basins where it deposits forming deltas, and turbidite deposits on the deeper ocean floor. Wind carries sediment out over the oceans. Gravity causes landslides that often continue into the marine environment, and sometimes take place entirely within the marine environment. Icebergs often carry rock out over the ocean floor and as they melt the rock drops to the sea floor. These ice-transported rocks are known as erratics. \n\nMuch of the deposition of rock material, or what eventually becomes rock, in the marine environment comes from biological sources. Plankton die and sink to the ocean floor, coral reefs build huge platforms (Florida for example) that become limestone rock. Many marine organisms use calcium carbonate to form shells and other parts of their structure, marine algae often contain calcium carbonate, and many microscopic marine organisms precipitate calcium carbonate and some other minerals as part of their biological processes. \n\nChemical deposition also occurs in the marine environment, and deposits of calcium carbonate (very few, but some), salt (halite, sylvite, etc.), and calcium sulfate in the form of gypsum or anhydrite occur as a result of oversaturation conditions in ocean water. Often this deposition only occurs when special conditions exist that confine a portion of an ocean basin and allow the concentrations of dissolved minerals to build up. An example would be the Mediterranean Sea during the Messinian Salinity Crisis in the late Miocene.
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Oceanic crust is fundamentaly different from Continental because of its origin.  Oceanic crust is formed as the continents move apart and new 'material' is forced between the plates.  You may have seen the video of lava being extruded at the bottom of the ocean 'toothpaste style'.  This forms round lumps of 'pillow lava' which have no crystals (because it cooled very quickly the crystals don't have time to form).  Below this you'll see the same material (chemically) but which forms columns of basalt (like Giant's causeway in Ireland) as it cooled slower.  Below this is the layered basalts which will form a much more massive block of basalt.  Below this is peridotite.\nChemically speaking oceanic material is basaltic whereas continental is granitic.\nContinental volcanic rocks are a lot less systematic in structure as they just intrude through thick layers of other material although they'll generally have larger crystals and will be lighter in colour.  \nBecause of their increased silica content they're more explosive and so this will be seen by the steeper sides of the volcanoes, pumice (solidified ash), etc.
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Great question!  If you are truly looking for a scientific answer, remember that science must be observable.  During our lifetime, a similar (yet much smaller) catastrophe occurred which provided scientific evidence of how the Grand Canyon was actually formed . . . Mount St. Helens.\n\nAt Mount St. Helens eruption, the entire mountain was rearranged beyond recognition within 9 hours.  Deep canyons were formed within five months.  Layered rock strata formed in three hours.  A river system formed in nine hours.  Sinking logs looked like aged forests within just ten years.  Also, a new model for understanding coal formation was adopted . . . all because of what could be observed at Mount St. Helens eruption.\n\nConsequently, much has been explained about how the Grand Canyon was formed; we no longer have to guess.  The Grand Canyon is a lasting monument of the worldwide flood during the life of Noah in approximately 2458 BC.  Up until the time of Mount St. Helens, geologists never imagined such changes could occur in such a short amount of time.  If you see what occurred at Mount St. Helens in our lifetime (in just a few hours and months), you can easily understand how the Grand Canyon was formed during a worldwide flood with erupting volcanoes, massive landslides and receding waters at rapid speed.  That’s science!\n\n'The catastrophic erosion of Grand Canyon (probably a result of drainage of lakes) was associated with river-terrace gravels, lake sediments, landslide deposits, and lava flows of the post-Flood period,” says Steven A. Austin. (Reference #3)\n\nCheck out the 'Answers in Genesis' website for lots of great information.  Best wishes on your search for truth and quest for knowledge . . . !  May you continue to search as if looking for a hidden treasure . . . !
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This is the Wilson Cycle, and it is driven by plate tectonics. \n\nContinents are composed of relatively light weight felsic igneous rocks such as granites and granodiorites. Ocean basins are composed of mafic igneous rocks like basalt and gabbro that are heavier than continental crust. Since the earth's mantle is plastic, these different masses of rock tend to 'float' at different levels. This is called isostacy.\n\nOceanic plate motion originates at the mid-ocean ridges, pushing oceanic plates outward towards the continents. This motion and force is far from being uniform from one ocean basin to another, and is not even consistent along the length of the mid-ocean spreading centers. \n\nWhere oceanic plates meet continental plates there is a convergent plate boundary and generally this leads to subduction of the oceanic plate. There is considerable force however, and the style of subduction does vary. Since the forces that are being applied, as well as the resistance of the continental plates all are varied, there are inequities that cause the continents to move in one direction. Eventually this motion results in a collision of continents called a supercontinent because continents will not subduct under one another. India and Asia, and the Himalayas are a great example of a continental convergent plate boundary. Eventually the convection forces that cause the supercontinent to form will begin rifting it apart again creating new smaller continents. \n\nHere is a model of the Wilson Cycle:\nhttp://csmres.jmu.edu/geollab/vageol/vahist/wilsonsimp.html
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Magma, or molten rock located beneath the earth's surface, cools upon reaching the surface to form the crust. This crust is moved away from the location of upwelling by thermal convection currents in the semi-plastic mantle. The crust is then resorbed back into the mantle upon meeting another, less dense (more buoyant) crust. \n\nThere are two types of crust: oceanic and continental. Each are made from different minerals, resulting in oceanic crust being 'heavier' (denser) and thus sinking below the 'lighter' (less dense) continental crust at convergent boundaries. The earth's crust is in a state of constant motion (or, in some places, no motion, but a building up of energy) called plate tectonics. \n\nSee the wikipedia link below for more details. Hope that helped.
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The Mariana Trench (or Marianas Trench) is the deepest known submarine trench (35,798 feet), and the deepest location in the Earth's crust itself. It is located in the floor of the western North Pacific Ocean, to the east of the Mariana Islands
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continental drift explained why similar plants and animals were found on opposite on the ocean, similarly why similar fossil assemblages and rock types were found on opposite sides of the ocean, for example in Europe and North America , and Africa and South America. Continental drift explained these occurrances by suggesting that the landmasses had previously been joined but had split, and the new continents drifted apart, taking animals plants rocks, fossils with them.\n\nIt also explained why marine fossils were found on top of mountains, as the theory of continental drift suggested that just as continents drifted apart, they could also collide, and the collision would raise the landmass up.\n\nIt also explained why volcanic activity occurs in certain places in the world, ie along the edges of moving plates.
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The magnetic striping of the seafloor is similiar on both sides of an oceanic rift.  They match up like puzzle pieces.
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SafariX Textbooks Online - Essentials of Oceanography, Eighth EditionThe existence of sea floor spreading was confirmed when the Glomar Challenger began the Deep Sea Drilling Project to sample ocean sediments and the ... \nhttp://www.safarix.com/0131635719/ch04lev1sec9\n\nSpreading of the Ocean Floor: New Evidence -- Vine 154 (3755 ...Sediment Distribution on the Mid-Ocean Ridges with Respect to Spreading of the Sea Floor. J. Ewing and M. Ewing (1967). Science 156: 1590-1592 | Abstract ... \nhttp://www.sciencemag.org/cgi/content/abstract/154/3755/1405\n\nThe Active Part of Charlie-Gibbs Fracture Zone: A Study Using Sonar and Other Geophysical Techniques … - group of 2 »\nR Searle - J. Geophys. Res, 1981 - osti.gov \n... SEA-FLOOR SPREADING; ATLANTIC OCEAN;GEOLOGIC FAULTS;OCEANIC CRUST;PLATE\nTECTONICS;SEDIMENTS;SONAR. ... geophysical instruments has revealed new information ...\nhttp://www.osti.gov/energycitations/product.biblio.jsp?osti_id=6458102\n\nContinental breakup and the onset of ultraslow seafloor spreading off Flemish Cap on the Newfoundland rifted margin \nhttp://geology.geoscienceworld.org/cgi/content/abstract/32/1/93\n\nTransition from continental break-up to punctiform seafloor spreading: how fast, symmetric and … - group of 5 »\nG Corti, JW Van Wijk, M Bonini, D Sokoutis, S … - Geophys. Res. Lett, 2003 -\n http://scholar.google.com/url?sa=U&q=http://www-pord.ucsd.edu/~wilbert/JOLANTE/bestanden%2520Jolante/Corti2003.pdf\n\nI could not find much on it but I hope these links help. If not, just put what your looking for into the search bar to do more research on it. good luck.
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Are you serious? ;) Well, I'll try to be:\n\n1. Continents are made up mostly of intrusive or plutonic granitic rocks, oceanic crust of extrusive or volcanic basaltic rocks. Example: compare some Himalayan rock with a hardened lava fragment from Mauna Loa in Hawaii.\n\n2. Continental rocks are lighter and of greater volume - they therefore protrude above the oceanic crust, if you dig very deep down they also have deeper roots. The oceanic crust is denser but thinner.\n\n3. Continental rocks are in general much older. This doesn't mean that oceanic rocks didn't exist before, but they get swallowed up (well, buried real deep and remelted, etc.) in trenches, the deepest parts of the oceans.
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It exists, but there's no real mystery about it anymore. The main theory is that it's just pockets of methane gas under the ocean floor. When the gas escapes, it lowers he density of the water big time and any ship caught in it's path will sink almost instantaneously, it also messes with plane engines if enough of it enters the air in dense enough pockets.
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Alfred Wegener, German meteorologist, was gathering climate information with a partner when he started noticing glacial deposits that matched on different continents.\n\nThis led to more study of course. Why were similar deposits found in such far removed places?\n\nWhile looking into this, he also noticed that rocks & fossils on different continents were also identical.\n\nThis, along w/ the "continent puzzle" led to his hypothesis of continental drift. Notice, it is referred to as a hypothesis. This is because Wegener could never provide a driving mechanism for continental drift.\n\nWegener tried explaining how continents could move but to no avail. His explanation that the continental crust literally plowed through oceanic crust did not "cut" it. PUN intended. This was not possible w/o leaving torn crustal plates behind & there was no evidence of that.\n\nMost scientists rejected his hypothesis. Some, however, kept searching for the "driving mechanism" behind continental drift.\n\nIn 1968, scientists could finally provide this force behind the movement of the crust. It was named the theory of plate tectonics.\n\nThis theory stated that the earth's crust was broken down into many major & minor lithospheric plates. These plates moved due to uneven heating of the molten magma in the earth's mantle.\n\nConvection currents w/in the mantle are created by cooler magma sinking & hotter magma rising. As the hotter magma rises towards the asthenosphere, it will cool & then sink. This principle works in the same manner as it does in the atmosphere.\n\nPlates were either pulled apart at divergent boundaries or subducted at convergent boundaries unless it is at two continental convergent boundaries. In this case the two crusts are less dense than the magma below & will deform rather than be subducted.\n\nSo yes, Alfred Wegener did suggest the theory of continental drift. But it was not actually taken seriously until the theory of plate tectonics came along.