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56 Cards in this Set
- Front
- Back
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What are the four things that cause junctions of land and sea?
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waves and tides, gradual changes in sea leve, biological processes and tectonic activity
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What is the place where ocean meets land?
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Shore
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The larger zone that has processes at boundary such as, marshes, sand dunes, cliffs, inland and beach and sandbars, troughs immediatley offshore. It is active
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Coast
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How is the location of a coast determined?
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It depends on global tectonic activity and the volume of water in the ocean.
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How is the shape of a coast determined?
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its a product of many proceses: uplife and subsidence, the wearing down of land by erosion.
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What is the difference between active and passive coasts?
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Active coasts are near the leading edge of moving continental plates, passive coasts near trailing edges.
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What are the 5 factos that can cause sealevel to change?
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1. amount of water in the ocean ( glaciation)
2. seafloor spreading 3. global warming 4. techtonic motions 5.winds and currents, seiches, storm surges- el nino |
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What is Eusatic change? and which factors of these factors are examples?
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Eustatic change- variations in sea level that can be measured allover the world ocean.
1. glaciation 2. seafloor spreading 3. global warming |
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What is local sea level change? and what causes it?
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change that is only found in one area of the ocean.
1. techtonic motions 2. storms/wind/currents |
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What are Erosional Coasts?
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new coasts in which the dominant processes are those that remove coastal material.
( seacliffs) |
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What are depositional coasts?
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are steady or growing because of their rate of sediment accumulation or the action of living organisms ( corals)
Ex: Maine |
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What determines the rate of erosion?
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the hardness and resistance of the rock, the violence of the wave shock to which it is explosed, and the local range of tides.
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What are high energy coasts?
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areas frequentl battered by large waves. ( marinecoast)
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What are low energy coasts?
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ares that are infrequently battered by large waves. ( usually proteced by offshore islands) erode slowley
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What is a seacliff?
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A seacilf is a slope that goes abruptly from land into the ocean. Steepness- collapse of undercut notches.
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What are sea caves?
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caves only accessable during low tides- made by many waves.
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What is wave-cut platform?
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marks the submerged limit of rapid marine erosion.
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How are shoreline straightened by selective erosion?
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through wave refraction
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fjords
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deep narrow bays often formed by tectonic forces and later modified by glaciers ( U- shape troughs) ( found in Alaska)
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how might volcanic activity shape a coast?
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if volcanic activity is recent- coast will consist of lobed lava flows. craters at the coast may fill with seawater after volcanic activity has slowed.
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What happens when a fault moves downward?
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a stte escarpment that continues to a greater depth than a wave-cut cliff can result
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What happens when a fault moves upwards?
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the part of the coast previously submerged during high tides can be left high and dry.
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what is found on a depositional coast?
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usually composed of sediments. erosional shores develop into this. Erotional to depositional.
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What is a beach?
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a beach is a zone of loose particles that covers part or all of the showre. happens when sediment is transported to places for desposition. They are a constant state of change. the flatter the beach the finer it is.
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What is the relationship between a beach slope and particle size?
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wave energy, particle shape and packed sediments.
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What are the effects of small waves on a beach?
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waves- sand moves towards the shore then away.
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What is berm?
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the accumulation of sediment that runs parallel to shore and marks the normal limit of sand deposition by wave action.
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what is berm crest?
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the peaked top of the highest berm. ( highest point on a beach)
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What is the backshore?
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Inland of the berm crest, extending to the fartheset point where beach sand has been deposited ( relativley inactive portion of the beach)
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What is the foreshore?
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seward of the berm crest- is the active zone of the beach, washed by waves during the daily rise and fall of the tides. extends from base of berm to low tide mark where offshore zone begins
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what is a beach scarp?
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a vertical wall of variable height-
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What is a longshore trough?
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waves make this.
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What are longshore bars?
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They are submerged or exposed accumulations of sand- they complete the seaward profile.
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What are beaches like in the winter?
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They are cut shorter because of winter waves/storms
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What is a bay mouth bar?
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it forms when a sand spit closes off a bay by attaching to a headland adjacent ot the bay. - protects bay from waves turbulence
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What is an inlet?
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a passage to the ocean- it may be cut through a bay mouth bar by tidal action, by water flowering from a river emptying into the bay, or heavy rains.
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what are barrier islands?
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barrier islands exposed sandbars that are parallel to but separated from land ( happens on depositional coasts)
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what is a lagoon?
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a long, shallow body of seawater islated from the ocean- when rising sea level caused the ocean to break through the dunes
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what is a sea island?
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not like barrier islands- they are composite structures that contain a firm central core that was part of the mainland when sea level was lower.
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distinguish between sand spits and bay mouth bars?
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a bay mouth bar forms when a sand spit closes off a bay by attaching to a headland adjacent to the bay
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what is the difference between sea islands and barrier islands?
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barrier islands are narrow, exposed sandbars that are parallel to but separated fromland. unlike barrier islands, sea islands contain a firm central core that was part ofthe mainland when sea level was lower
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Why don't deltas form at every river mouth?
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because a broad continental shelf must be present tidal range must be low and waves and currents generally mild.
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What is coral?
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a linear mass of calcium carbonate assembled from and by multittudes of coral animals.
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what is a frindging reef?
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they cling to the margins on the land. connects to shore near the water surface.
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What are barrier reefs?
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are separated from land by a lagoon. they occur at lower latitudes than fringing reefs and can form around island or in lines parallel to continential shores. grows slower because fewer nutrients are available.
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What is an attol?
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a ring shaped island of coral reefs and coral debris. a shallow lagoon in which no land pertrudes.- shallow continental shelves or deep sea oceans.
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What are mangroves?
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trees that grow in salt water.
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what is an estuary?
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a body of water partially surrounded by land where fresh water from a river mixes with ocen water.
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how are estuaries classified?
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1. drowned river mouths
2. fjords 3. bar-built 4. tectonic |
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what factors determine the characteristics of estuaries?
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the shape of the stuary, the volume of river flow at the head of the estuary, and the range of tides at the estuary's mouth.
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what is a salt wedge estuary?
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form where a rapid flow large river enteres the ocean in an area where tidal range is low or moderate.
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what is a well mis estuary?
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contain differing mixtures of fresh and salt water through most of their length. tidal turbulence stirs and water together as river runoff pushes the mixtures to sea.
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what are partially mixed estuaries?
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similar to the salt wedge the influx of seaer beneath a surfae layer of fresh water flowing seaward
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what is a fjord estuary?
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formed where glaciers have gouged sttp you shaped vallys below sea level, small surface areas, high river input, and little tidal mixing.
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what are groins?
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short extension of rock or other material placed at right angles to longshore drift to stop the longshore transport of sediments.
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what is a breakwater?
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interrupts progress of waves to the beach, weakening the longshore scurrent and allowing sand to accumulate there.
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