Coasts

• Determined by how coast is formed

• Primary Coasts

• Formed by natural land processes

• volcanic

• Hawaiian Island hot spot

• depositional

• Nile River Delta

• Secondary Coasts

• Formed by water processes affecting primary coasts

• erosion
• marine deposits

• coral reefs

Coastlines

• Ria Coasts

• Rise of sea level or a crustal sinking (or both) brings the shoreline to rest against the sides of river valleys previously carved by streams
• Become estuaries

• Fjord Coasts

• Similar to Ria Coasts
• But formed by submerged glacial troughs

• Barrier-Island Coasts

• Recently emerged coastal plain
• Low ridge of sand, short distance from the coast, created by wave action
• Increases in height as coastal winds fortify the island with dunes

• Delta Coasts

• Deposit of clay, silt, and sand made by a stream or river where it flows into a body of standing water
• Can grow rapidly, at rates ranging from 3 m (about 10 ft) per year for the Nile Delta to 60 m (about 200 ft) per year for the Mississippi Delta

• Volcano Coasts

• Arise where volcanic deposits—lava and ash—flow from active volcanoes into the ocean
• Beaches are typically narrow, steep, and composed of fine particles of the extrusive rock

• Coral Reef Coasts

• Unique because the new land is made by organisms—corals and algae
• Organisms secrete rock-like deposits of carbonate minerals, called coral reefs. As coral colonies die, new ones are built on them, accumulating as limestone

• Fault Coasts

• Faulting of the coastal margin of a continent can leave the shoreline resting against a fault scarp.
• In central California, near the coastal town of Lucia, the continental shelf is very narrow, suggesting that the marine cliffs there are the result of faulting.