Erosion is the process of wearing away
and breaking down of rocks in that area.
Coasts made of hard rocks are worn
away over hundreds of years, with most
of the erosion occurring during
storms-when waves are most powerful.
Types of weathering
acidic rainfall which
dissolves weak minerals
and causes rocks to
salt crystals causes
stresses in the rock
which later breaks.
Biological weathering- From
plants which cause rocks to
break, e.g with roots,stems
Suspension- Fine sediment
is carried as suspension in
the water, this is what
makes water looks dirty.
Solution- Dissolved material is
carried along and you cant see it.
Traction- Bigger pebbles and cobbles
are rolled along the sea bed.
Saltation- Small pebbles moved when one
pebble hit another,making it bounce. This
bouncing sets up a reaction.
Longshore drift is another way of coastal transportation. The first thing
that happens is that the waves approach the beach at a 45 angle,
because the waves break the swash would carry material and deposit
up to the beach because gravity is available some material might be
taken away due to the backwash of the waves. This means the
sediment movement would be moved along in a zig zag route. The
movement of material is known as longshore drift.
Process for longshore drift
Destructive Waves - Waves that have a weak swash
and a strong backwash pull sand and pebbles back
down the beach when the water retreats. They are
called destructive waves because they remove material
from the beach. They are often steep, high waves that
are close together and crash down on to the beach.
Constructive Waves - These are waves that have a
strong swash but a weak backwash. due to this these
waves build up the beach. They push sand and pebbles
up the beach and leave them behind when the water
retreats, this is because their backwash is not as strong
enough to remove the material. They are often low waves
with longer gaps between them
The size of a wave is dependable on
many factors, for example how strong and
how long the wind blows for. Fetch is how
far a wave has travelled in a given time.
Mass Movement is when rocks loosened by
weathering move down slope under the influence
Rockfalll / sliding - This is one of the ways how rock can
loosen. This is the process when huge rocks would sllide
down the slope quickly without any warning. This can
make it hazardous for people to walk across the beach.
Rock fragment are fallen off the steep cliff due to the
influence of gravity.
Slumping is another process of mass movement this is
where when cliffs are made of clay. Due to the clay
becoming saturated during heavy rainfalll it would ooze
down towards the sea as part of a mud or debris.
Hydraulic Action- This is when strong waves crash into the
cliff face. The trapped air is blasted into holes and cracks in
the rock causing them to break apart.
Attrition - Rock fragments carried by the sea knock
into each other, they break down and become smaller
Abrasion - Fragments of rock are picked up and hurled at
the cliff by the sea. They scrape and gouge the rock.
Solution- Chemical action of the
water where salts and acids in
the water can dissolve rock.