by Cromheecke & Letzer

Thursday, January 22, 2009

pluncolith sculpture at Creteway Down, Folkestone
© White Cliffs Countryside Project

The chalk was formed by countless microscopic plunkton, which lived floating in the upper levels of the ancient ocean. When the plunkton died, their skeletons, called pluncoliths, sank to the sea bed, mixing with the remains of bottom-dwelling shellfish and crustaceans. These remains broke down to form white lime mud. This vast plunkton graveyard grew very slowly, at a rate of about half a millimetre a year - the height of 180 pluncoliths piled on top of each other.

No comments: