Geology Site Account

Site name: Debden Puddingstone

Grid reference: TL 550 332

Brief description of site:

Next to a public footpath west of Debden parish church is a very fine, round boulder of Hertfordshire puddingstone about a metre in diameter.

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Details

At the side of the public footpath behind Debden Parish Church is a round boulder of Hertfordshire puddingstone about 1.05 x 0.9 x 0.65 metres in size. The boulder has colourful pebbles and is very conspicuous next to the path, despite being masked by stinging nettles in the summer.

Hertfordshire Puddingstone was formed around 55 million years ago when the climate of Britain was hot and a layer of pebbles beneath the surface of the ground became cemented with quartz. They are thus very resistant to erosion and have survived the rigours of the Ice Age. They originated in Hertfordshire, hence the name, and were probably carried to Essex by the River Thames when it flowed north of its present course. However, the distribution and abundance of Hertfordshire puddingstone in parts of Essex suggests that some occurrences may have a local Essex source.

The formation of silcretes (which includes sarsens and puddingstones) has been the subject of recent scientific debate. Research has compared the conditions under which sarsens and puddingstones may have been formed with the present day climate in the Kalahari Desert and parts of Australia.

Debden Puddingstone. Photo: G. Lucy