Stack (geology)
Stack, near Old Harry Rocks.
Old Harry Rocks
A
stack is a
geological landform. Stacks are steep, often vertical, sided columns of rock in the sea, near coasts. Stacks are formed when part of a
headland is
eroded leaving a small
island. These also form when a
natural arch collapses due to sub-aerial processes and
gravity. A stack may collapse or be eroded leaving a stump. Stacks form most commonly on
chalk cliffs, because of the medium resistance to
erosion. Cliffs with weaker rock, such as
clay tend to
slump and erode too quickly to form stacks, while harder rocks, such as
granite erode in different ways.
Examples
