Coastal Geology
5 questions tagged Coastal Geology — spanning every one of the seven Ws.
Why do deltas form where rivers meet the sea?
Deltas form because a river slows down when it enters still water, dropping the sediment it carries. If sediment supply is high enough, the deposit builds outward into a fan-shaped landform.
Why do beach sands differ from one coastline to another?
Beach sand reflects the local rocks, shells, coral, and river sediments that supply it. Waves and currents sort the grains by size, shape, and mineral type.
How do river deltas build new land at the mouth of a river?
When a river slows down as it reaches still water, it drops sediment that accumulates into a delta.
Why do some beaches have black sand instead of light-colored sand?
Black sand usually comes from volcanic minerals or lava fragments weathered into tiny grains. Minerals like basalt, olivine, and magnetite give the sand its dark colour.
Why do some coastlines have cliffs while others are flat and sandy?
Cliffs form where waves erode resistant rock faster than sediment can build up. Flat coasts usually have abundant sand or softer material that waves can redistribute.