View
216
Download
0
Category
Preview:
Citation preview
DEPOSITIONAL COASTAL LANDFORMSare varied and often associated with each other:
• beaches
• sand bars
• sand spits
• tombolos
• beach ridges
• beach cusps
• cuspate forelands
• barrier islands
• coastal sand dunes
• washover fans
• salt marshes
• tidal flats
• lagoons and bays
• tidal deltas
• river deltas
MAJOR OCEANIC MATERIAL INPUTS
• Input source input amount– Rivers 84%– Glaciers 9%– Windblown dust 3%– Coastal erosion (higher than ave. locally) 1%– Volcanic debris <1%– Groundwater flow <2%
A well-defined, lobate sediment plume is seen emerging from a river source on this stretch of wave-dominated (beach-fronted) Atlantic coastline. Currents are starting to carry some of the sediment northward in the offshore environment. Note the broad, well-"fed" beaches in the direction of sediment transport and narrower, retreated beaches in the opposite direction. Typically, river input and cliff erosion are the
major sources of sediment for a coastline (Space Shuttle, March 1994).
Plum Island, Mass.Plum Island, northeastern Massachusetts, low altitude, oblique, aerial view of barrier island with beach-dune ridge showing washovers, vegetated backdunes, & back-barrier marsh with tidal channels (16 July 1975).
Beach ridges on a barrier island• McLaughlin's Beach (southwest end of Ninety Mile Beach),
Victoria, Australia Recent Low altitude, oblique, aerial view of low-angle truncation of multiple beach-dune ridges (chenier ridges). This once prograding coastline was retreating, at least locally when this picture was taken (1976).
Development on a Barrier IslandOcean City, Maryland, U.S.A.Modern Beach island modification: Ocean City, a developed barrier island. Host to 8 million visitors a year, this city (and others similarly situated) has no effective protection against
flooding and damage from severe storms.
Recommended