Arches are formed when
destructive waves (waves which
Teacher
form erosional features along
Student
the coast) strike against the base
of headlands to form caves. The
erosional processes of corrasion
(the physical action of sand and
rock fragments carried by waves
being hurled against the base of
cliffs leading to their
breakdown) and hydraulic
Measuring
action (the force of waves as
they repeatedly break against a
Sand
cliff, causing fragments of rock
to become dislodged) lead to the
Plate 4: Measuring the width of an Arch
formation of caves in the area
between high and low tide. As these processes continue on either side of a headland the caves
formed become deep enough to meet each other, creating a tunnel through the headland
known as an Arch. Students observed several arches which were not quite large which
indicated small amounts of erosion. (See Plate..)
Arc
Due to constant wave erosion of
Arches, Stacks are formed
S
when arches are widened,
eventually, the roof of the Arch
cannot be supported anymore
and breaks off and falls into the
sea. The seaward part of the
Sta
headland becomes detached
from the rest of the headland and
is called a Stack. When Stacks
are repeatedly eroded they are
Sa
known as Stumps.
In the study area a stack was
Plate : Stack Found In Middle
found which was quite eroded
and some distance away from
the headland indicating frequent strong erosional processes leading to its deterioration. ( See
Plate..)