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Unformatted text preview: 10/31/2008 1 Coastal Processes and Coastal Processes and Landforms Landforms • Oceans – largest bodies of water: Pacific, Atlantic, Indian, Southern, and Arctic • Seas – next largest water bodies: Black, Mediterranean, Barents, etc. • Gulf – next largest, usu. opens to larger water body: Mexico, Alaska, Guinea, etc. • Bay – smaller still: Fundy, Biscay, etc. Water as Solvent Water as Solvent • Salinity – concentration of dissolved solids in seawater – global seawater salinity 34-37 parts per thousand (‰) • Brine – water with >35‰ salinity • Brackish water - <35‰ salinity Shaping the Coastline Shaping the Coastline • Key to shaping coastline is movement of water • Eustatic Change - changes in water level in ocean – due to tectonic uplift or hydro cycle variation • Land above sea level forms river valleys that Land above sea level forms river valleys that extend to sea level – when sea level rises, valley floods, as with Chesapeake Bay or Delaware Bay • Ria – river valley flooded by rising sea level • Fjord – glacial valley flooded by rising sea level North American Coastline North American Coastline through Time through Time Lowest sea levels occurred during glaciations when water was tied up in glaciers (130k & 19k bp) – highest sea levels in interglacial periods (120k bp) 10/31/2008 2 Tides Tides • Regular, predictable oscillations of sea level – due to gravitation of moon (56%) & Sun (44%) • High tide on side of Earth facing moon and on side away from moon – ellipsoid shape • Long, narrow bays usu. have highest tides – up to 16 meters in Bay of Fundy in eastern Canada Waves Waves • Oscillations in water due to force of friction from wind blowing across its surface • Waves travel horizontally, but most movement of...
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- Spring '11
- Erosion, sea level, Coast, Coastal geography, Longshore drift