The BGS Lexicon of Named Rock Units — Result Details

Bytham Sand and Gravel Formation

Computer Code: BYTH Preferred Map Code: notEntered
Status Code: Full
Age range: Early Pleistocene (QPE) — Mid Pleistocene (QPM)
Lithological Description: The formation encompasses fluvial, lacustrine and organic deposits of the Bytham River. Commonly a basal coarse-grained gravel is overlain by red fine- to medium-grained sand. The gravels are composed of Triassic grey and purple quartzite, vein quartz, Jurassic limestone and ironstone, and Carboniferous sandstone and chert. Sedimentary structures imply deposition in a braided river environment. The gravels are distringuished from the Baginton Sand and Gravel Formation to the west by their including a significant proportion of Jurassic as well as Triassic material.
Definition of Lower Boundary: Unconformably overlies Jurassic bedrock.
Definition of Upper Boundary: Commonly overlain by Middle 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: Individual aggradations are usually 3 to 5 m thick; may total 18 m locally.
Geographical Limits: The deposits occupy the valley of the pre-Glacial Bytham River from Castle Bytham east through Witham-on-the-Hill towards the Fen edge south of Bourne.
Parent Unit: Bytham Catchments Subgroup (BYCA)
Previous Name(s): Bytham Formation [Obsolete Name and Code: Use BYTH] (-3890)
Bytham Sands And Gravels Formation (-744)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Gravel pit, Thurderbolt Pit, 800 m east of Castle Bytham. Rose, 1989b; Lewis, 1993. 
Reference(s):
Rose, J. 1987. Status of the Wolstonian glaciation in the British Quaternary. Quaternary Newsletter, Vol.53, 1-9. 
Rose J. 1989b. Castle Bytham. 117-122 in Keen, D H (editor), The Pleistocene of the West Midlands: Field Guide. [Cambridge: Quaternary Research Association.] 
Rose, J. 1994. Major river systems of central and southern Britain during the Early and Middle Pleistocene. Terra Nova, Vol.6, 435-443. 
Rose, J. 1989. Tracing the Baginton-Lillington Sand and Gravel from the West Midlands to East Anglia. 102-110 in Keen, D H (editor), The Pleistocene of the West Midlands: Field Guide [Cambridge: Quaternary Research Association.] 
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:
E176 E190 E142 E156 E157 E143