Weather, Erosion and Coastlines

• Weather and erosion are natural processes that shape the Earth's surface

Weather and Erosion

• Wind carries sand and other small particles over distances, forming sand dunes and eroding farmland
• Over time, windblown sand and soil can change the shape of rocks

Erosion by Ice

• Glaciers erode the earth and create landforms in cold regions and mountaintops
• Glaciers move slowly downhill, transporting materials from tiny grains to large boulders
• Rocks carried by glaciers scrape against the ground, eroding both the ground and rocks

Thermal Erosion

• Thermal erosion is the erosion of permafrost along rivers or coastlines
• Warm temperatures cause ice-rich permafrost to break off coastlines in large chunks, carrying topsoil and vegetation
• Eroded "floating islands" can disintegrate into the ocean or crash into other land, spreading new life

What is a coastline?

• A coastline is where land meets the sea or ocean
• Coastlines include beaches, cliffs, capes, caves, bays, and estuaries
• These features can be located close together along a coastline
• Smaller landforms can be lined up along a coast

Coastal Features

• Natural arch: An arch hollowed out of a headland by the sea
• Rocky islet: a small island made of rock
• Stack: Needle-shaped column of rock resulting from the collapse of an arch
• Spit: Elongated ridge of sand or pebbles extending into the water
• Cliff: steep rock face shaped by a sea
• Headland: a tapering strip of land jutting into the sea
• Tombolo: Ridge of sand joining an island to the shoreline
• Beach: Accumulation of sand or pebbles along a coast
• Dune: Accumulation of sand shaped by the wind
• Cave: Natural underground cavity formed by water erosion

Rivers and tides

• River estuary: Mouth of a river influenced by tides, forming an indentation in the coastline that varies in width and depth
• Lagoon: Shallow expanse of seawater separated from the sea by a ridge of sand or a barrier island

Coastal Processes

• The coast is the land along a sea, and the coastline is the boundary where land meets water
• Waves, tides, and currents create and modify coastlines
• Waves erode the land but can also leave behind materials like shells and seaweed

Long term effect on Coastlines

• Coastal changes occur over long periods
• The hardness of the material determines how easily a coast erodes; harder materials like granite are more resistant
• Tides affect sediment deposition on the coast
• Areas with large tidal ranges have sediment deposited farther inland
• High-energy waves carry more sediment and rock particles

Factors shaping the coastlines

• Larger waves carry more energy and move more sediment or rock particles
• Coastlines with big beaches allow waves to spread out energy and deposits
• Small beaches focus wave energy, resulting in a tattered appearance
• Strong storms can crack rocky coastlines and wash away sandy beaches

Changing Coastlines

• Coasts can indicate natural events like weather patterns and sea level changes
• Storms can cause flooding in coastal areas
• Coastal plains are flat, low-lying lands exposed when sea levels decrease
• Coasts can be affected by pollution, oil spills, and garbage, which negatively impact their appearance and marine life