Where results make sense

About us   |   Why use us?   |   Reviews   |   PR   |   Contact us

Continental shelf - Wikipedia, the free encyclopedia The continental shelf is the extended perimeter of each continent, which is covered during interglacial periods such as the current epoch by relatively shallow seas (known as shelf seas) and gulfs. Though the continental shelf is treated as a physiographic province of the ocean, it is not part of the deep ocean basin proper, but the flooded margins of the continent. The pelagic (water column) environment of the continental shelf constitutes the neritic zone, and the benthic (sea floor) province of the shelf is the sublittoral zone. en.wikipedia.org /wiki/Continental_shelf   (797 words)

M15.htm Continental shelves make up the fringes of both the oceans and continents, comprising about 7.4% of the total ocean surface, and less than 2% of the total volume of the world's oceans. The widths of continental shelves vary considerably, in some areas they are very wide (about 1500 km), while in other areas a shelf barely exists at all. Because continental shelf waters are so shallow, most of the biomass produced in the water column does not have far to sink before it is intercepted by the bottom and the benthic biota. www.meer.org /M15.htm   (374 words)

Continent - Search View - MSN Encarta In addition, the continental masses include the submerged continental shelves, which slope gently from the ocean shores of the continents to depths of about 183 m (600 ft); at approximately this point begins the more abrupt plunge to the oceanic depression known as the continental slope. If the continental shelves are taken into account, the total continental area increases to 35% of the earth's surface. The study of the history and origins of continental drift is called plate tectonics because, in charting the directions that the continents have taken, geologists discovered that the earth's crust and upper mantle are divided into a number of semirigid plates, each of which has recognizable boundaries and moves as a unit. encarta.msn.com /text_761553387__1/Continent.html   (686 words)

Continent - ninemsn Encarta In addition, the continental masses include the submerged continental shelves, which slope gently from the ocean shores of the continents to depths of about 100 fathoms (183 m/600 ft); at approximately this point begins the more abrupt plunge to the oceanic depression known as the continental slope. If the continental shelves are taken into account, the total continental area increases to 35 per cent of the Earth's surface. The study of the history and origins of continental drift is called plate tectonics because, in charting the directions that the continents have taken, geologists discovered that the Earth's crust and upper mantle are divided into a number of semi-rigid plates, each of which has recognizable boundaries and moves as a unit. au.encarta.msn.com /encyclopedia_761553387/Continent.html   (620 words)

ocean - HighBeam Encyclopedia The continental shelves are the regions of the oceans best known and the most exploited commercially. It is assumed that submarine canyons on the continental shelf were initially carved during periods of lower sea level in the course of the ice ages. Their continental slope extensions were carved and more recently modified by turbidity currents—subsea "landslides" of a dense slurry of water and sediment. www.encyclopedia.com /doc/1E1-ocean.html   (3188 words)

Continental drift - EvoWiki   (Site not responding. Last check: 2007-10-13) Continental drift is the theory that the Earth's crust is divided into plates that move relative to each other, with their interactions producing a variety of geological features. This continual drifting has been described as "continental bumper cars", and some geologists theorize that the periodic accretion and fracturing of continental masses may be a necessary part of a geologic cycle. The modern concept of continental drift was first proposed by German meteorologist Alfred Wegener; he pointed out the biogeographical details that Suess had pointed out, and he pointed out that Permian glaciers in the southern continents had flowed from oceans -- unless those continents had been united to form Gondwana back then. wiki.cotch.net /index.php/Continental_Drift   (870 words)

Continental Shelves - MarineBio.org Continental shelves were formed in between glacial periods as the ocean flowed over the continents forming shallow areas along the coasts. Normal continental shelves are found in the South China Sea, the North Sea, and the Persian Gulf and are usually about 80 km in width with a depth of 30-600 m. Continental shelves are an oasis in the ocean for plants and animals due to the abundance of sunlight, shallow waters, and nutrient packed sediment that washes in from rivers, wave action, and, in some areas, upwelling. marinebio.org /Oceans/ContinentalShelves.asp   (759 words)

Amateur Geologist Structured Geological Glossary: The Ocean At the edges of the shelves the continental slope drop rapidly from 100 to 200 m to 3000 to 3700 m. The declivity from the offshore border of the continental shelf at depths of approx. Continental derived sediment located seaward of large rivers or submarine canyon having a cone-shape or fan-shape. www.amateurgeologist.com /content/glossary/ocean/ocean.html   (1275 words)

Introduction to Physical Oceanography : Chapter 3 - The Physical Setting - Sea-Floor Features The deep, lighter continental crust oats higher on the denser mantle than does the oceanic crust, and the mean height of the crust relative to sea level has two distinct values: continents have a mean elevation of 1100 m, oceans have a mean depth of -3400 m (Figure 3.5). Continental (or island) shelves are zones adjacent to a continent (or around an island) and extending from the low-water line to the depth, usually about 120 m, where there is a marked or rather steep descent toward great depths. Canyons are common on shelves, often extending across the shelf and down the continental slope to deep water. oceanworld.tamu.edu /resources/ocng_textbook/chapter03/chapter03_03.htm   (793 words)

Veronica Trigg   (Site not responding. Last check: 2007-10-13) The heat from the molten material is conducted to the continental material above, reducing its density and causing it to float higher in the mantle, producing a ridge of mountains above the spreading center. The size of the continental rifts will vary depending on the rate of spreading and the amount of heat flowing into the rift, which is regulated by the possible volcanoes or fissures. The evolution of passive continental margins can be described in two ways: rapid thinning of the lithosphere, accompanied by subsidence, as a result of a loss of buoyancy, then as the lithosphere cools as a result of growth and gain in weight of the mantle. www.eas.slu.edu /People/Students/triggvj/paper.html   (1040 words)

Chapter 14: The Ocean Floor The continental shelf is the submarine extension of the continent. The continental slope is a narrow, steep region that connects the conti-nental shelf to the oceanic crust (Figure 14.6, p. Some narrow continental margins, such as the one off the coast of California, are dissected by submarine canyons that reach up to the surf zone in places. mywebpage.netscape.com /GWBlaylock/Geol1010/Chapter14.html   (1519 words)

Case 4. Freshwater discharges over idealized continental shelves   (Site not responding. Last check: 2007-10-13) The experiments have been conducted for idealized shelves with 1) a linear slope and a straight coastline and 2) a linear slope with a curvature coastline. The open boundary is located at 800 and 1400 km downstream from the origin for FVCOM and POM, respectively, at which a gravity wave radiation boundary is specified to allow the wave energy to propagate out of the computational domain with minimum reflection. To ensure minimum influence of the open boundary on the numerical solution in the computational domain over the time scale in which we are interested, the open boundary for POM is moved to 1400 km away from the origin. codfish.smast.umassd.edu /MValidation/Case4.html   (1017 words)

margin terrigenous sediments Lying between these two areas are the continental shelf sediments bounded by a continental or island landmass with coastal environments on one side and a deep ocean basin on the other. On broad shelves without a major source of fluvial sediments, the burial of relict sediments has just begun and sediments on about 60% of continental shelves of the world are Sand waves, common on many continental shelves, are essentially normal or parallel to the shoreline. geology.uprm.edu /Morelock/GEOLOCN_/margsedptt.htm   (3787 words)

Acadia National Park - FLOW: Coastal Zone   (Site not responding. Last check: 2007-10-13) Being rich in marine and fossil life, continental shelves are marked by sometimes conflicting uses as living marine habitats and sources of undersea fuels. The continental slope is a continuation of the coastal plain and slopes gently downward (0.1 degree) away from the coast. Roughly half of the continental shelves of the world are gone over by weighted fishing gear every year. www.nps.gov /acad/flow/zone.html   (501 words)

Department of Marine Science Hence sedimentation along continental shelves is different from in the deep sea. Coral reefs on the shelves were exposed and died during the low stand of the sea. Shelves were ground and beveled by the grinding mill of the surf zone. www.usm.edu /marine/mar151/MAR_151_Chap_4b.html   (1013 words)

IGCP464   (Site not responding. Last check: 2007-10-13) The project is a follow-up of the previous IGCP396 “Continental shelves during the Quaternary”. Mapping of continental shelves and shelf breaks as assistance to countries, particularly less-developed countries, in the perspective of submissions on shelf geometries for claims under the Law of the Sea Convention. The conditions at the LGM on continental shelves and their effects on coastal plains and continental slopes will thus be the "starting point" of the most recent and continuing environmental cycle. tetide.geo.uniroma1.it /igcp464   (11763 words)

continental drift. The Columbia Encyclopedia, Sixth Edition. 2001-05 On the basis of geology, biology, climatology, and the alignment of the continental shelf rather than the coastline, he believed that during the late Paleozoic and early Mesozoic eras, about 275 to 175 million years ago, all the continents were united into a vast supercontinent, which he called Pangaea. In 1928, Scottish geologist Arthur Holmes suggested that thermal convection in the mantle was the mechanism that drove the continental movements. The theory of continental drift was not generally accepted, particularly by American geologists, until the 1950s and 60s, when a group of British geophysicists reported on magnetic studies of rocks from many places and from each major division of geologic time. www.bartleby.com /65/co/contin-dr.html   (510 words)

Background on Continental Shelf Prehistoric Archaeolgy The continental shelves of the world were exposed by lower sea levels at the end of the last Ice Age and they were flooded as the ice sheets melted and drained to the oceans. However, sustained research to find continental shelf submerged prehistoric sites is only now beginning to take place, and there is a lot to learn about how to find these kinds of sites, and what to do once you do. As far as we know now the climatic regime on the exposed continental shelf of Florida during the late Pleistocene was like that known from pollen studies for the onshore areas. home.comcast.net /~mfaught/continentalshelf/cont_shelf_principles.html   (951 words)

::: Papua New Guinea Expedition ::: The Earth's continental plates are an average 125 kilometers thick and were formed more than 3 billion years ago. Continental Shelf - Shallow, submerged margin of the continents that lies between the edge of the shoreline and the continental slope. Continental Slope - Steeply sloping portion of the continental crust found between the continental shelf and continental rise. sio.ucsd.edu /png/glossary   (1423 words)

Sedimentation and Continental Growth The form that this "new land" takes depends on a number of factors: the age of the continental margin, the shape of the continental shelf, as determined during the rifting process, and the presence or absence of a subduction zone adjacent to the continental margin. As the continental margins move farther from the heat flow at the spreading, the mountains formed along the continental margins cool and slowly subside back into the mantle. The continental margins discussed in the preceding section are known as passive margins, where the continent and the adjoining ocean floor are part of the same plate. webspinners.com /dlblanc/tectonic/sediment.php   (1320 words)

Jamaica Gleaner - Continental shelves plans to commence flights to Ja - Wednesday | September 19, 2001   (Site not responding. Last check: 2007-10-13) JAMAICA'S TRAVEL industry was dealt another blow yesterday as a result of last week's terrorist attacks on the United States, when Continental Airlines announced that it would shelve plans to commence flights to the island later this year. Continental announced it would end flights to 10 cities as part of moves to pull down service in face of slowing air travel. JTB is working assiduously to minimise the impact of whatever fallout there might be from this incident," she said. www.jamaica-gleaner.com /gleaner/20010919/lead/lead5.html   (268 words)

World Builders Seaweeds The shelves may be narrow, less than 50 miles in width, or they may extend out a long way, perhaps as much as 500 miles. At the edge of the continental shelf there is a steep drop to much deeper waters, and the cold darkness of the lightless sea. Several of the aquatic biomes that we are studying are located on the continental shelves. curriculum.calstatela.edu /courses/builders/lessons/less/les5/shelves.html   (672 words)

The occurrence and chemical implications of geothermal convection of seawater in continental shelves The occurrence and chemical implications of geothermal convection of seawater in continental shelves Geothermal convection is an important driving force for fluid flow and diagenesis in carbonate platforms, and the similar shape of continental shelves in general suggests that geothermal convection could occur in continental shelves around the world. Citation: Wilson, A. The occurrence and chemical implications of geothermal convection of seawater in continental shelves, Geophys. www.agu.org /pubs/crossref/2003/2003GL018499.shtml   (257 words)

A Re-assessment Of The Archaeological Potential Of Continental Shelves : Summaries 2002-2003 : ALSF Projects : ... Although the recognition of the high archaeological potential of the submerged sections of the globes continental shelves can be dated back to Sir Charles Lyell (1872) this realisation has been overlooked by generations of archaeologists and historians. The specific geographical areas of interest to this study are the continental shelves which can be defined as the submerged parts of the continental margin, which slope very gently seawards, from the coastal zone (> 0 m depth) to the shelf break (c. These large scale features aside, the morphology and sedimentology of individual continental shelves is dictated by the complex interplay of both modern and geo-historical factors, including: global and regional fluctuations in sea-level; variability in sediment input rates and sources; and finally modes and rates of sediment transport. www.english-heritage.org.uk /server/show/ConWebDoc.5231   (2515 words)

COAST - Continental Margins - Continental Shelf These areas, where the oceans cover a portion of the continental land mass, are called continental shelves. Averaging approximately 60 meters in depth, these shelves slope gradually away from the shore at a rate of about 12 meters every kilometer. At the edge of the continental shelf is an area called the continental slope, a much steeper zone that drops away to the ocean floor. www.coast-nopp.org /visualization_modules/physical_chemical/basin_coastal_morphology/principal_features/continental_margins/continental_shelf/shelf.html   (103 words)

Case Study With the discovery of oil by Greece in 1973 off the coast of Thassos, a northern Aegean island, the continental shelf issue was thrust to the center stage of the historical dispute in the Aegean. Turkey stated that their continental shelf claims were justified by “special circumstances” related to the proximity of the Greek islands to the Turkish coast. The Turkish insistence on a demarcation line for the continental shelf midway between the Greek and Turkish mainlands intensifies Greek fears that there would be a direct threat to the sovereignty of the islands lying to the east of the line. www.american.edu /projects/mandala/TED/ice/AEGEAN.HTM   (2339 words)

IngentaConnect Estimating palaeobathymetry of wave-graded continental shelves fr... IngentaConnect Estimating palaeobathymetry of wave-graded continental shelves fr... Estimating palaeobathymetry of wave-graded continental shelves from sediment texture The concept of the wave-graded continental shelf, with sea floor sediment coarsening from offshore mud to shoreface sand, has been well known from the time of Johnson (1919). www.ingentaconnect.com /content/bsc/sed/2005/00000052/00000002/art00003   (421 words)

Types of ecosystems - Artisanal fisheries are generally restricted to the shallower areas of these shelves, while semi-industrial and industrial fleets (with which artisanal fisheries often conflict) can exploit both the nearshore and offshore areas. are very productive continental shelves found mostly at the eastern boundaries of the oceans, often in front of arid zones or deserts. The usually wind-driven, upwelling process brings cold, nutrient-rich water from deep layers into the euphotic zone where photosynthesis uses sunlight and the upwelled nutrients to produce the organic matter that is the basis of the marine food chain. www.oceansatlas.org /cds_static/en/types_ecosystems__en_3320_all_1.html   (679 words)

Try your search on: Qwika (all wikis)

About us   |   Why use us?   |   Reviews   |   Press   |   Contact us   Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.