Heydon Chalk Pit Local Geological Site

The pit. owned by Heydon Parish Council, was designated a Local Geological Site in February 2023. This disused quarry has exposures of the Lewes Nodular Chalk, rarely exposed in Cambridgeshire. Also, structural features indicative of disturbance of Chalk at ice-contact margin, with Chalk breccia here either glacial or periglacial in origin, overlain at one location by till (diamicton) which is regarded as part of the Lowestoft Formation. It is very possible that at least part of the exposures here represent Chalk rafting. It is a safe and accessible site to study the character of Lewes Nodular Chalk, the story of the formation of the Chalk, and the effects of glacial (including an ice sheet) and periglacial conditions.

The quarry is mentioned as a site for Chalk rafts in relation to the Anglian glaciation, in at least two publications.  The exposures show minor structural features indicative of glacio-tectonic activity at an ice-contact margin. The strata appear to be faulted with laminae of red-brown silt injected along bedding planes which are tilted in a direction contrary to the Chalk’s regional dip to the south east.

The quarry has been a significant source of rock for local building material. It supplied rock for use as local building material such as in road construction and floors of village cottages from the 1500s.

The exposed quarry faces encircle a County Wildlife Site with chalk grassland, and a green space and orchard’ for villagers, situated in a typical Chalk landscape of spurs and dry valleys.

The site is on the southern side f the wider Cam Valley and there are spectacular views nearby across the Rhee Valley to the north.