Limestone cliff face, Punakaiki, Paparoa National Park

Limestone, rich in calcium carbonate, gives rise to some of the most exquisitely sculpted rock formations to be found in the natural world. Calcium carbonate is soluble in water and it is the action of water on exposed limestone over hundreds or thousands of years that gives it its characteristic fluted or scalloped appearance.

Limestone underlies much of the Paparoa National Park on the South Island’s West Coast, and the action of the sea on exposed coastal cliffs has resulted in a wide range of spectacular coastal landforms, including the well-known Pancake Rocks at Punakaiki which are made up of layered type of limestone called dolomite.

The cliff face in this photograph is located just north of Punakaiki, in a small bay where centuries of constant wave action has undercut the limestone to form a natural amphitheatre. A layer of vivid green, courtesy of a species of saltwater algae, marks the high tide level on the rock face with a splash of colour, underlining the fact that this bay is very much inaccessible when the tide is in.