The BGS Lexicon of Named Rock Units — Result Details

Roxham Sand Member

Computer Code: RXB Preferred Map Code: RxB
Status Code: Full
Age range: Tithonian Age (JI) — Tithonian Age (JI)
Lithological Description: Grey and yellow-green, pyritic, silty sands with an indurated basal pebbly sandstone with black chert phosphatic nodules and derived Kimmeridgian debris. Bioturbation and burrows occur in the unit and may extend down into the top of the underlying Kimmeridge Clay.
Definition of Lower Boundary: Unconformable contact at the down-section change from sands, with a pebbly base, to mudstones of the Kimmeridge Clay Formation. An erosion surface separates the two units.
Definition of Upper Boundary: Disconformable, where green, glauconitic, clayey sands with abundant black phosphatic nodules of the Runcton Member overlies grey and yellow-green, pyritic, silty sands of the Roxham Member.
Thickness: Up to 6 m.
Geographical Limits: The member crops out between the Babingley River, southwards to near Southery, where it disappears beneath the Methwold Fens. It has been penetrated by a number of boreholes at Hunstanton, North Wootton, Gayton, Mundford and Little Ouse. The member extends under The Wash and has been recognised in borehole 72/77B, but passes laterally into the lower part of the Spilsby Sandstone Formation.
Parent Unit: Sandringham Sands Formation (SAS)
Previous Name(s): Roxham Beds [Obsolete Name and Code: Use RXB] (-1157)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Pratt's Bridge, Roxham Farm, West Dereham. Casey and Gallois, 1973. 
Reference Section  Hunstanton Borehole. Gallois, 1994. 
Reference Section  Gayton Borehole. Gallois, 1994. 
Reference Section  BGS Wash Borehole 72/77B. Wingfield et al., 1978; Gallois, 1994. 
Reference Section  Marham Borehole. Gallois, 1994. 
Reference(s):
Casey, R and Gallois, R W. 1973. The Sandringham Sands of Norfolk. Proceedings of the Yorkshire Geological Society, Vol.41, 1-22. 
Casey, R 1973. The ammonite succession at the Jurassic-Cretaceous boundary in Eastern England. In Casey, R and Rawson, P F [editors], The Boreal Lower Cretaceous [Liverpool: Seel House Press.] 
Gallois, R W, 1994. The geology of the country around King's Lynn and The Wash. Memoir of the British Geological Survey, Sheet 145 and part of 129 (England and Wales). 
Wingfield, R T R, Evans, C D R, Deegan, S E and Floyd, R. 1978. Geological and geophysical survey of The Wash. Report of the Institute of Geological Sciences, 78/18, 32pp. 
Rawson, P F. 1992. Cretaceous, 355-388 in Duff, P McL D and Smith, A J (editors), Geology of England and Wales. (London: Geological Society.) 
Hopson, P M, Wilkinson, I P and Woods, M A. 2008. A stratigraphical framework for the Lower Cretaceous of England. British Geological Survey. British Geological Survey Research Report, RR/08/03. 
Gallois, R W. 1984. The Late Jurassic to Mid Cretaceous rocks of Norfolk. Bulletin of the Geological Society of Norfolk, Vol.34, 3-64. 
Whitaker, W and Jukes-Browne, A J. 1899. The geology of the borders around The Wash: including Boston and Hunstanton. Memoir of the Geological Survey of England and Wales. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E159 E173