Field Guide to the Geology of North Norfolk
Beeston - West Runton
Parking: large car park at West Runton beach (Woman Hythe) sign posted from village (TG 184432). The proprietor makes a small charge, payable at the cafe or to an attendant in the season. No charge in winter. Also free parking at Beeston Regis church, then walk around the east end of churchyard and make your way westwards along the cliff to the excellent private steps and down the beach.
Access: best from West Runton (Woman Hythe). Also possible from private steps down from Beeston Regis Caravan Park at the west end of the section.
The Chalk is only exposed at low water.
Immediately to the west of Woman Hythe a small swale of the West Runton Freshwater Bed outcrops in the upper beach and cliff base, although not always exposed. It is less fossiliferous than the main deposit. Above it are silts of the Cromerian III transgression. Below it, on the seaward side of the revetment, are pebbly marine sands and silts of the Lower Pleistocene, including two stone beds. The lower of these, on the Chalk, is the Cromer Stone Bed, rich in local flint; while the upper includes quartz and quartzite pebbles brought from the Midlands and North by pre-Anglian river systems (Lee et al). These deposits rest on the Chalk platform where due to the hardness of the Cromer Stone Bed which caps the Chalk in places, small pedestals are created by marine erosion. The foreshore exhibits the only rock pools on the Norfolk coast and is rich in exhumed paramoudra flints.
Image: A long raft of Chalk and super-incumbent Wroxham Crag have survived their entrainment in the Happisburgh Till. Photo courtesy of Russell Yeomans.
In the cliff are good sections of the Anglian tills (Contorted Drift) displaying banded diamictons in the lower part of the cliffs and highly contorted tills and sand pods in the upper part. At intervals along the cliff are prominent basins of sand several tens of metres across. A fresh interpretation (Phillips et al 2008) demonstrates that ice moving from the west to the east has deformed pre-existing glacial sediments pro-glacially, forming basins of deposition that have filled as the deformation has progressed. The limbs of the basins are bounded by prisms of till that have been up-thrust in the shortening process.
The master interpreter at work. Dr Emrys Phillips of the British Geological Survey, who has mapped and interpreted the cliff section from Weybourne to Runton, is explaining at the 2010 Geologists Association field meeting to West Runton how glacial ice was coming from the west and thrusting and deformed pre-existing drift and while also creating syngenetic sand basins that accumulated in the developing synclines. At this point, below the sand basin under the beach car park we are debating whether a sedimentary structure (below) is a fossil ice-wedge cast or a water-escape structure (he convinced us it was the latter).
H.F. Burke, E.R. Phillips, J.R. Lee, and Ian P. Wilkinson 2009. Imbricate thrust stack model for the formation of glaciotectonic rafts: an example from the Middle Pleistocene of north Norfolk, UK. Boreas 38 Issue, 620-637.
Jane K. Hart, 1987. The Genesis of the North East Norfolk Drift. PhD. Thesis UEA
E.R. Phillips, J.R. Lee, and H.F. Burke 2008. Progressive proglacial to subglacial deformation and syntectonic sedimentation at the margins of the Mid-Pleistocene British ice sheet: evidence from north Norfolk, UK. Quaternary Science Reviews. 27, 1848-1871
R.G. West, 1980. The pre-glacial Pleistocene of the Norfolk and Suffolk coasts. Cambridge University Press, 34-45
Compiled by Martin Warren. Last updated 14.1.2011