(calm music)
M1: Sea cliffs are the main erosional landform of coastlines.
We're now down at the base of the cliffs
to look at their features and how they're formed
by some of the erosional processes that we've talked about.
(footsteps)
M2: So we're down here at the base of the cliff
and this is the high energy zone.
Between the high water mark that we can see here,
where the rock changes colour.
All the way down to the low water mark where the
sea is at the moment.
And this is the high energy zone,
where the marine erosional processes
act on the cliff more rapidly than the sub-aerial processes.
Over time, these processes are going to act on
the base of the cliff, they start to under cut it
and a wave-cut notch is formed.
The sea and all those erosional marine processes
are acting on the base of the cliff,
undercutting the cliff until it can't hold its own weight.
And it eventually collapses.
M1: And when the cliff collapses
all the material ends up down here at the base of the cliff,
where we can see it's now being broken down
and rounded by the attrition processes
that we've talked about.
(clattering)
M2: This sequence of events happens again and again and again
over time, forcing the cliff to retreat inland.
This leaves behind this wave-cut platform,
which we can see gently sloping out to sea.
(seagulls crowing)
(footsteps)
It's textbook, isn't it?
It is literally the perfect wave-cut platform right here,
sloping down into the sea.
M1: You can see that the surface
of the wave-cut platform is really uneven.
That's due to slight differences
in the erodibility of the rock,
which means that some patches,
some areas, erode faster than others.
M2: It's differential erosion, isn't it?
M1: It's a perfect example
of differential erosion.
M2: Careful here, it's slippery.
(rock music)