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Ocean

Opening And Closing Of Ocean Basins

Oceans, like most natural phenomena, exist across a span of time called a "life cycle." For a new ocean to be born, the earth's crust beneath an ocean or a continent must be torn, or rifted, apart.

An ocean basin ceases to exist because its lithosphere gets entirely subducted (that is what usually happens) or obducted (rare and localized). An ocean basin no longer grows when its mid-oceanic ridge gets pulled down into a subduction zone, or gets crammed into a mountain range on the side of a continent. If it is not growing any larger in area, then it can not replace the area it loses to subduction and obduction. Eventually the processes of subduction and obduction put all the oceanic crust of the dying ocean basin either under bordering continents (by subduction) or on top of the bordering continents (obduction). This life cycle of an ocean basin is the same no matter how long it takes or how large the ocean gets to be.

What happens to the water in the dying ocean? Remember, this process takes tens of millions of years. The water flows gradually into other oceans as the basin shrinks, and also departs through evaporation and precipitation.

Resources

Books

Borgese, E., ed. Ocean Frontiers. New York; Harry N. Abrams Inc., 1992.

Brower, K. Realms of the Sea. Washington DC; National Geographic Society, 1991.

Carson, R. The Sea Around Us. New York, Oxford University Press, 1989.

Earle, Sylvia A., and Eric Lindstrom. Atlas of the Ocean: The Deep Frontier. Washington, DC: National Geographic Press, 2001.

Fischer, G., and G. Wefer. Use of Proxies in Paleoceanography. Berlin Heidelberg: Springer-Verlag, 1999.

Hamblin, W.K., and Christiansen, E.H. Earth's Dynamic Systems. 9th ed. Upper Saddle River: Prentice Hall, 2001.

Pinet, Paul R. Invitation to Oceanography. Boston: Jones & Bartlett, 2003.

Sverdrup, Keith A., et al. An Introduction to the World's Oceans. New York: McGraw-Hill, 2002.

Thurman, Harold V., and Alan P. Trujillo. Essentials of Oceanography. 7th ed. Englewood Cliffs, NJ: Prentice Hall, 2001.

Periodicals

Lee, Thomas. "Eleventh AMS Conference on Satellite Meteorology and Oceanography." Bulletin of the American Meteorological Society 83, no. 11 (2002): 1645-1648.

Other

National Oceanic & Atmospheric Administration (NOAA). <http://www.noaa.gov>

Clinton Crowley

KEY TERMS

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Continental shelf: —A relatively shallow, gently sloping, submarine area at the edges of continents and large islands, extending from the shoreline to the continental slope.
Maritime climate: —A moist climate that is neither too hot nor too cold, caused by the moderating effect of water on temperatures.
Pelagic sediment: —Sediment that exists in the open ocean, away from land.
Pillow lava: —The form that basaltic lava takes when it is erupted deep under water.
Trenches: —The deep, trough-like depressions in the ocean floor that oceanic crust descends into when it is destroyed.
Turbidity currents: —Local, rapid-moving currents that result from water heavy with suspended sediment mixing with lighter, clearer water. Causes of turbidity currents are earthquakes or when too much sediment piles up on a steep underwater slope. They can move like avalanches.

Additional topics

Science EncyclopediaScience & Philosophy: Nicotinamide adenine dinucleotide phosphate (NADP) to Ockham's razorOcean - Origin Of Ocean Water, Lithospheric Plates And The Origin Of The Seafloor, Weather Effects Of Ocean Waters - Hydrologic cycle