ocean waves and currents change the face of coastal areas Chapter 3 Hydraulic ActionPressure air being forced into crack in rocks Corrosion Solution Minerals such as calcium carbonate amp limestone dissolve in the water ID: 409062
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1.5 Understand how ocean waves and currents change the face of coastal areas. (Chapter 3)Slide2
Hydraulic Action/Pressure - air being forced into crack in rocks.
Corrosion (Solution)
Minerals such as calcium carbonate & limestone dissolve in the water
Abrasion
rock & sand particles suspended in the water bump, grind, scrape & gouge surfaces the water hitsSlide3
Hydraulic ActionHydraulic action is a form of
mechanical weathering
Caused by the force of moving
water currents rushing into a crack in the rockface. The water compresses the air in the crack, pushing it right to the back. As the wave retreats, the highly pressurized air is suddenly released with explosive forceCapable of chipping away the rockface over time. Slide4
Hydraulic ActionSlide5
Emerging vs. Submerging CoastlinesEmerging
Caused by lowering water levels and/or rising land level
Land “springing up after glacier is gone.
Steep land features, cliffs etc.
SubmergingCaused by RISING sea levelsWere once river valleys now submergedResults in more sand from deltas and/or outwash plainsLower, gradual slopeSlide6
Define the terms
bay beach
bay bar
spit
(P. 44-45)Slide7
Bay BeachSmall beach of sand found between two peninsulas or headlands
An accumulation of sediment deposited by waves and longshore drift along a bay.Slide8
Bay Beach – Bonne BaySlide9
Bay BeachSlide10
Spit
Ridge of sand projecting from the land into a body of water
usually with a curved seaward end.
Spit grows in the prevailing direction of longshore drift.
Ends are curved by the action of waves in different directionsSlide11
SpitSlide12
SpitWhat can you tell about the direction of long shore drift?
Is there any indication a bay bar might form?
Sandy Point Newfoundland!Slide13
Spit - CaliforniaSlide14Slide15
Bay BarA ridge of mud, sand or silt extending across a bay.
Formed when spits stretch across the mouth of the bay
Notice the spit has
closed off the mouth of the harbor/bayWould these be a tourist attraction or distraction?Slide16
Bay BarSlide17
Goodyear’s Cove, South Brook, NL. ?Slide18
Bay Beach
2. The point of land on top of the picture would be called?
Where does all the beach sand come from? Can you propose two sources?Slide19
Define the terms
bay beach
bay bar
spit
(P. 44-45)Are these landforms caused by erosion or weathering?Slide20
Describe how sea caves, sea arches and sea stacks are formed. (P. 48)
These three coastal structures occur on “emerging” coast lines with steep cliffs & a headland.
1
st
Sea caves form , 2
nd
sea arches form and 3rd sea stacks form.