y currents* trenches:* deepest part of the ocean* narrow asymmetrical valleys* subduction zone topographic features* islands and seamounts:* hot spot chains, mantle plume* guyots and atolls* submerge with age* continental margins: adjacent to collision/subduction zone* continental shelf- submerged portion of continent* continental slope- slope beyond shelf margin-submarine canyons-turbidity currents-deep-sea fans* continental rise- gentle slope where basin meets continentCoasts: Coastal Erosion* ocean waves and wave motion:* wave base- depth (L/2), lower limit of wave motion* breaking waves- distortion due to decrease in depth* height increases* wavelength decreases (successive crests)* front of the wave steppes and breaks as the rear part continues to move forward* surf: wave activity between the breakers and the shore, turbulent motion of water* wave refraction: bending of waves due to a change in direction of travel caused by approach at an angle to the shoreline* smooth, irregular coasts reduced* erosion by waves:* erosion below sea-level- due to surf, limited to 1.5x wave height* abrasion in the surf zone- wearing down of rock by rock particles* erosion above sea-level- mainly during stormsCoasts: Sediment Transport* sediment transport by waves and currents:* longshore currents- current in surf zone, parallel to shore* beach drift- transport of sediment along the shore, zigzag* beach placers- concentration of heavy minerals* offshore transport and sorting: seaward of the surf zone* sediments moved by currents and storm waves* energy of wave motion decreases with depth* sorting of particles due to increase in depth* normally grade seaward from sand into mud* shore profile: vertical section through shore* on beach coasts:* beaches- wave-washed sediment on a coast including surf zone* foreshore- zone from lowest tide to average high-tide* berm- bench formed of sediment deposited by waves* backshore- zone extending inland from berm to ...
