Geology Site Account

Site name: Doggetts Pit

Grid reference: TQ 8788 9147

Brief description of site:

Doggetts Pit provides the only exposures of Rochford Gravel. The site is now a fishing lake.

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Summary of geological interest

Doggetts Pit provides the only exposures of Rochford Gravel. Rochford Gravel is an infilling of the Rochford Channel which is thought to have been cut by the Thames about 400,000 years ago (MIS 11) shortly after the diversion of the river by the Anglian ice sheet. The Rochford Channel is therefore an upstream equivalent of the famous Clacton Channel.

The well-bedded sandy gravel in Doggetts Pit is capped by a layer of brickearth or loam which has penetrated the underlying gravel in ice wedges, which were said to have been spaced at intervals of 10 to 15 metres along the old working face. Patterned ground with fossil ice-wedge polygons is present in the adjacent fields and can be seen on aerial photographs. The site is now a popular fishing lake with sandy gravel exposed in the banks.

Alluvial loam, and 'brickearth' overlying Rochford Gravel seen in the disused pit at Doggetts in 1973. Photo © British Geological Survey (P211773).