Geology Site Account

Site name: Crumps Farm Quarry

Grid reference: TL 582 210

Brief description of site:

Working gravel quarry with exposures of Kesgrave (Thames) Sand and Gravel and London Clay.

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Details

The gravel pit at Little Canfield worked the Kesgrave Sands and Gravels which were deposited by the River Thames when it flowed far to the north of its present course at least 600,000 years ago. At the base of this gravel, and lying directly on the underlying London Clay, is a layer of pebbles up to 70 centimetres (22) thick that was identified in 1988 as the basal pebble bed of the Red Crag and laid down in a shallow sea over 2 million years old (Mathers & Zalasiewicz 1988).

In 1991 the pit was re-excavated and a large expanse of London Clay was temporarily exposed. In this clay was a number of fine fossil lobsters that lived on the sea floor 50 million years ago. Also within the London Clay were flat, spherical septarian nodules up to 35 centimetres (one foot) in diameter, the surfaces of which displayed intricate patterns which represented the infilled burrows of marine creatures such as crustaceans. This indicates that the London Clay, which was originally mud on the sea floor, is intensely burrowed throughout but evidence of this is only visible on the nodules.

The quarry is private property and permission for access should be obtained from the quarry operator.