Ch 20 Flashcards
Currents are essentially agents of
Deposition and transportation
Waves generated by winds are essentially agents of
Erosion
The most notable landforms produced by waves are
Rocky cliffs and head lands
Most common landforms produced by currents are “deposition all features”:
Beaches and sad bars
beaches are built up in “” and eroded in “”
Normal weather
Storms
Erosion and deposition are part of “” the distinctiveness of coastal Milieu involve the transfer “interphase” of energy from the atmosphere(air) to the hydrosphere(ocean) to the lithosphere.(land) large water=larger effects of coastal processes.
Coastal processes
Waves and wind
Geomorphic agents
Most important great influence in coastal lines. Generates waves. Topography of large body of water can be deformed abruptly by this. A deformation creating waves and ocean currents shapes coastlines.
Wind
Causes erosion
A disturbance on water caused by energy passing through it.
Wave
Energy and mass move differently. Moves back and forth over the same space again and again. Gentle phenomenon.
Wave of oscillation
Same horizontal direction, power force of destruction.
Translation
Long shore currents. Tides and tidal currents. Volcanic eruptions. Tidal(storm) surges. Long term (tectonic/climate)effects on sea level change. Reef building corals. Sea ice. Glaciers.
Other agents
Hydraulic pounding
Chemical action
Sea cliff erosion
Wave erosion
Small waves/large storm waves, spray from breaking waves,debris, air, hurling water, much coastal erosion by eave rock particles. More abrasive
Hydraulic pounding
Most rocks soluble in sea water. Salts from seawater crystallize in crevices and pores of onshore rocks/cliffs. This deposition mechanism makes rocks weaker and breaks them up with salt wedging
Chemical action
Most effective erosion / at or slightly above sea level, notches cut off on base of cliffs.
Des cliff erosion.
A seismic sea wave -retreating :pulling back. Triggered by disruption on sea floor.
Tsunami
Irregular rise. Result from gravitational influence of sun/moon topographic effects are small. Only significant in narrow bays. Shallow seas.
Tides
Motion of wave in which the individual particles of the medium (such as water) make a circular orbit as the wave form passes through.
Wave of oscillation
The horizontal motion produced when a wave reaches shallow water and finally “breaks” on the shore
Wave of translation
Phenomenon whereby waves change their directional trend as they approach a shoreline, results in ocean waves generally breaking parallel w/the shoreline.
Wave of refraction
Long sinuous ridge of stratified glacial drift composed largely of glacial fluvial gravel and formed by the chocking of subglacial streams during a time of glacial stagnation.
Esker
Change in sea level due to an increases or decrease I’m the amount of water in the world ocean.
Eustatic sea level change/eustacy/eustatic force.
A linear deposit of marine sediment that is attached to the land at one or both sides
Spit
A spit formed by sand deposition that connects an island to the mainland. Less common but more distinctive, deposited feature. Connects near shore island w/mainland.
Tombolo
A body of quiet salt or brackish water in an area between a barrier island or a barrier reef and the mainland. Extensive barrier island isolates the water between itself and the mainland, and forms a body of quiet salt of brackish water.
Lagoon
Long narrow “sand bar “ built up on shallow offshore waters oriented parallel to the shore. island composed of sediment generally oriented parallel to the shore
Barrier island
Caused by tectonic uplift or sinking of land masses. Eustatic increase or decrease in volumes of water in ocean. (Pleistocene glaciations) thermal expansion. Glacial melting.
Consequences» sea level rise up to .5m (20”). Retreat of shorelines up to 3m. 100ft
Change in sea level and lake level.
Annual freezing of sea ice causes near shore ice to push against the land causing minor erosion and deforming the shoreline, “like small glacial advance”mostly in the Antarctic and arctic regions
Ice push
Aquatic animals= Calcium carbonate secretions. Reef-building organism that’s most important. skeleton of calcium carbonate “coral polyps”
Organic secretions
Source of sediment for beaches sand and sediment deposited mover around by coastal waters, I’d disrupted outflow, beaches along coastal lines may shrink
Stream outflow
Water moves parallel to the shoreline. Transporters of sediment
“Along the shore”
Longshore currents
Linear strand of marine sediment attached to shore formation extends out to open water in a down current direction and usually involves longshore current transport and
Spit
Spit becomes extended clear across the mouth of a bay to connect w/land on the other side, and transforming the bay into a lagoon.
Bay mouth bars
