The BGS Lexicon of Named Rock Units — Result Details

Shouldham Sand and Gravel Formation

Computer Code: SMSG Preferred Map Code: notEntered
Status Code: Full
Age range: Early Pleistocene Epoch (QPE) — Mid Pleistocene Epoch (QPM)
Lithological Description: The formation encompasses fluvial, lacustrine and organic deposits of the pre-Glacial Bytham River, At the type site, yellowish red to brownish yellow cross-stratified sands, with minor beds of pebbly sand, overlie sands and gravels. In the lower unit, massive and planar cross-stratified gravels alternate with planar cross-stratified, thick bedded massive pebbly and trough-bedded sands. Clast analysis of the gravels (11.2-16.0mm fraction) indicated 60.1% quartz and quartzite, 19.0% flint, 12.1% chert and 7.0% ironstone, and quartzite is derived from Triassic pebble beds to the west, chert from the Carboniferous, and flint from the local Chalk.
Definition of Lower Boundary: Unconformable on Cretaceous bedrock.
Definition of Upper Boundary: Commonly overlain by Mid Pleistocene glacigenic deposits. Upper boundary may be difficult to determine where overlain by glaciofluvial sand and gravel, but the presence of more angular clasts, chalk, and poorer sorting in the latter is usually helpful.
Thickness: c.6m
Geographical Limits: Deposits occupy the valley of the pre-Glacial Bytham River from Shouldham Thorpe, Norfolk, southwards along the eastern margin of the Fens, as far south as High Lodge, Mildenhall.
Parent Unit: Bytham Catchments Subgroup (BYCA)
Previous Name(s): Shouldham Sands And Gravels (-2436)
Shouldham Sands (-531)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Gravel pit 800m northwest of Shouldham Thorpe. Lewis, 1991. 
Reference(s):
Lewis, S J. 1991. Shouldham Thorpe. 127-130 in Lewis, S J, Whiteman, C A and Bridgland, D R (editors), Central East Anglia and the Fen Basin: Field Guide. [London: Quaternary Research Association.] 
Rose, J. 1987. Status of the Wolstonian glaciation in the British Quaternary. Quaternary Newsletter, Vol.53, 1-9. 
Lewis, S G. 1993. The status of the Wolstonian glaciation in the English Midlands and East Anglia. PhD Thesis, University of London. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E159 E160 E173 E174 E189