Presentation on theme: "Coastal Erosion. Forces That Shape The Earth The Earth is shaped by both internal and external processes Internally, tectonic processes form the lithosphere."— Presentation transcript:
Forces That Shape The Earth The Earth is shaped by both internal and external processes Internally, tectonic processes form the lithosphere Externally gradational processes also shape the lithosphere These include: rivers, winds, glaciers, and waves
Rivers Rivers cut deep valleys and create large deltas
Winds Winds carves beautiful rock formations and carry sands
Glaciers Glaciers flow over continents while slowly carving out the land and dropping large boulders…
Waves Waves and currents cut into coastlines and polish sandy beaches….
The Other Gradational Force… Humans are a gradational force This picture is an example of the effects of over forestation
The constant battering of the waves (14,000 waves per day) Effects: –erode the shoreline –transport the eroded material –deposit the eroded material elsewhere Coastal Erosion
Factors Affecting Coastal Erosion Softer rocks are more easily eroded Sea floors that slope gradually have less erosion because wave break offshore Coastlines oriented perpendicular to prevailing winds erode more easily Rising sea levels increase erosion rates.
Signs of Coastal Erosion Wave-cut notches: An indentation cut into a sea cliff at water level by wave Sea caves: cave formed primarily by the wave action of the sea Sea arches: form where cliffs are subject to erosion from the sea Sea stacks: steep and often vertical column of rock in the sea near a coast, isolated by erosion
Wave Cut Notch
Sea Arches, Caves, Stacks
Sea Arches and Sea Stacks
Elephant Rock, PEI
Hopewell Rocks, NB
Preventing Coastal Erosion Riprap – a heap of angular boulders piled along the shoreline Breakwater – a wall of boulders built parallel to the shore to take the brunt of the breaking waves