Landforms and Landscapes of Coastal Deposition

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  • Created by: Om4r
  • Created on: 18-04-19 15:23
How do beaches form?
When constructive waves deposit sediment on the shore- Beach accretion
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How do Swash-Aligned Beaches form?
In Low energy environments e.g. bays, waves are roughly parallel to the shore
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How do Drift-Aligned Beaches Form?
Where waves approach the coast at an angle, Sediment transferred by Longshore Drift, Spits form on here
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Why do Larger Pebbles Tend to be near the top of the beach?
Constructive waves will carry a range of sediment size up a beach due to the strong swash, due to water percolating, weaker backwash can only drag back smaller pebbles- overtime pebbles are sorted with large at the top and smaller at the bottom
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What shape do pebbles at the bottom of the beach tend to be?
More rounded due to constant action of the waves causing abrasion and attrition
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How do seasonal changes affect Beach Profile?
Sediment is dragged offshore by destructive waves in winter and returned by constructive waves in summer
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What is the Beach profile like in the Summer?
Steeper than winter. More constructive than destructive waves, Constructive waves are less frequent and have a longer wavelength so wave energy dissipates and deposits over a wide area
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What is the Beach Profile like in the Winter?
More destructive than constructive waves, destructive waves occur at a higher frequency. Strong backwash transports sediment offshore
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What is a Spit?
A long narrow feature made of sand or shingle that extends from land into the sea
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At what type of Beach do Spits form?
Drift-Aligned beaches
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How do Spits form?
Sand or shingle is moved along the coast by Longshore (littoral) drift, due to a sudden change in the direction of the coastline . Sediment begins to build up across the estuary mouth, forming a spit.
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Why does the end of the spit begin to curve? What is it called?
Because wave refraction carries sediment into more sheltered water behind the spit. A recurved Tip
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What prevents the Spit from extending right across the Estuary Mouth?
The outward flow of the River
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What is a Tombolo?
A bar that connects an island to the mainland ( a beach that has formed between a small island and the mainland
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How do Tombolos Form?
Prevailing wind, and deposition due to loss of wave energy causes LSD to transport sediment forming a bar between an island and mainland
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What are Offshore Bars?
Spits that have connected two headlands together, across a bay or river mouth
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What forms behind the Offshore Bars?
Lagoons e.g. Slapton Ley
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How do Offshore Bars Form?
Destructive waves erode sediment from the beach and deposit it offshore
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What are Barrier Islands?
Long, Narrow islands of sand or gravel that run parallel to the shore and are detached from it
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Where do Barrier Islands Tend to form?
In areas where there's a good supply of sediment, a gentle slope offshore, fairly powerful waves and a small tidal range
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What is the Backshore zone?
Where sand dunes form at the back of the beach
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What is required for Sand dunes to form?
Large quantities of available sand, washed onshore by constructive waves a large tidal range and dominant onshore winds
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Why is a Large Tidal Range required for Sand dunes to form?
To create a large exposure of sand that can dry out at low tide
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Why are dominant onshore winds required for Sand Dunes to form?
To blow dried sand to the back of the beach
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What is each stage of a succession called?
A sere
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What are the 5 stages in Dune Succession?
Embryo/Fore Dunes, Yellow Dunes, Grey Dunes, Dune Slack and Heath/Woodland
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What are the Characteristics of Embryo and Fore Dunes?
Poor water retention. High water mark, Sand collects in shelter of rocks/wood
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What are the Characteristics of Plants that grow in Embryo/Fore Dunes?
Waxy leaves to retain moisture and withstand winds, High Salt tolerance and deep tap roots
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What are the characteristics of Yellow dunes?
Above level of high tides, Some Humus Forming, More water retention and reduced wind speeds
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What are the characteristics of Plants that grow in Yellow Dunes?
Long Tap roots, Salt tolerant and in rolled leaves to reduces water loss
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What are the characteristics of Grey Dunes?
Fixed Dunes, Higher Humus content, little mobile sand, lower PH
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What are the characteristics of Plants that grow in Grey Dunes?
Less salt tolerant, higher species diversity, Marram grass and perennials
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What are the Characteristics of Dune Slacks?
Acidic soil, occur in low lying hollows between dune ridges, high water table especially in winter
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What are Plant Characteristics in Dune Slacks?
Moisture Loving plants, commonly found in fresh water
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What are the Dune Characteristics in Woodlands?
Acidic soil, nutrient rich ,soil has a high organic matter
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What are Pioneer Species?
First Species colonising the area that begin the process of Succession, which have special adaptations to help them survive in hostile conditions
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What is the final seral stage called?
Climatic Climax Community
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What are Saltmarshes?
Areas of flat, silty sediments that accumulate around estuaries or lagoons
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What 3 types of Environment do Saltmarshes develop in?
Sheltered areas where deposition occurs, where salt and fresh water meet and where there are no strong tides or currents to prevent sediment deposition and accumulation
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Other cards in this set

Card 2

Front

How do Swash-Aligned Beaches form?

Back

In Low energy environments e.g. bays, waves are roughly parallel to the shore

Card 3

Front

How do Drift-Aligned Beaches Form?

Back

Preview of the front of card 3

Card 4

Front

Why do Larger Pebbles Tend to be near the top of the beach?

Back

Preview of the front of card 4

Card 5

Front

What shape do pebbles at the bottom of the beach tend to be?

Back

Preview of the front of card 5
View more cards

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