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Unformatted text preview: 1 GY 301: Geomorphology GY 301: Geomorphology Lecture 7: Coastal Plain Topography: Terraces UNIVERSITY OF SOUTH ALABAMA Last Time Coastal Geomorphology 1 Basic classification (substrate and energy) Processes (waves and currents) Topographic Features (lab prep) Coastal Geomorphology There are two main controls on coastal geomorphology: 1) Geological materials available on the shoreline Outcrop (rock) Gravel Sand Mud 2) energy of shoreline waves currents tides storms Coastal Geomorphology Although diverse, you can group most shorelines into one of 3 broad types: 1) Rocky (high energy [waves, tides, currents]; outcrop/rocks) 2) Beaches (high energy [waves]; sand and gravel) 3) Estuaries (low-high energy [tides]; mud) Bay of Fundy, Canada Rocky Coastline The irregular shape of rocky coastlines is a consequence of wave refraction ; the bending of waves as they approach a shoreline. Waves tend to bend toward headlands which focuses strong erosive forces around their periphery. Sandy Shorelines From Walker, R.G. and James, N.P. (1992). Facies Models: Response to Sea Level Change. Geological Association of Canada, 409p. They come in many forms: Barrier Islands Spits Strandlines Beaches (open/sheltered) 2 Sandy Shorelines Wave refraction will result in longshore currents and longshore drift Todays Agenda Coastal Geomorphology 2: Terraces Some definitions and types of terraces Terraces on topographic maps Sea level changes and terrace development Coastal Terraces Terraces: relatively flat plains formed by deposition or less commonly, by precipitation (hydrothermal processes)...
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- Fall '10