The BGS Lexicon of Named Rock Units — Result Details

St Bees Silt Member

Computer Code: SBSI Preferred Map Code: SBE
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Thinly interlaminated calcareous, bluish grey silty clay, reddish brown clay and yellowish brown silt passing upwards into ripple-drift cross laminated sand with much finely disseminated coal. Palaeocurrents mostly directed towards the northwest.
Definition of Lower Boundary: Not exposed, but BGS-registered borehole NX91SE5 near the type section indicates that it rests unconformably on stiff, reddish brown diamicton, probably the Lowca Till Member of the Seascale Glacigenic Formation.
Definition of Upper Boundary: Gradational, conformable contact with sand and gravel of the St Bees Sand and Gravel Member of the Seascale Glacigenic Formation above.
Thickness: At least 3.7m
Geographical Limits: Cumbrian coast between St Bees and Sellafield seaward of the limit of the "Gosforth Oscillation" between Cleator and Ravenglass.
Parent Unit: Seascale Glacigenic Formation (SEAG)
Previous Name(s): St Bees Silts And Clays (-3659)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Sea cliff section in the axis of large anticlinal fold 300m south of the southernmost groyne on St Bees Beach, Cumbria. Nirex, 1997. 
Reference(s):
Merrit, J W and Auton, C A. 2000. An outline of the lithostratigraphy and depositional history of Quaternary deposits in the Sellafield district, west Cumbria. Proceedings of the Yorkshire Geological Society, Vol.53, 129-154 
Huddart, D and Tooley, M J. 1972. The Cumberland Lowland field trip handbook. [Cambridge: Quaternary Research Association.] 
Eastwood T, and others. 1968. Geology of the country around Whitehaven. Memoir of the Geological Survey of Great Britain, Sheet 28 (England and Wales). 
Merritt, J W and Auton, C A. 1997. Quaternary lithostratigraphy of the Sellafield district. Nirex Science Report SA/97/045 (Issue 2.0). [Report prepared for UK Nirex Ltd. 69pp, 5 tables, 20 figures, 14 enclosures and one appendix.] 
Akhurst, M C, Chadwick, R A, Holliday, D W, McCormac, M, McMillan, A A, Millward, D, Young, B, Ambrose, K, Auton, C A, Barclay, W J, Barnes, R P, Beddoe-Stephens, B, James, J C W, Johnson, H, Jones, N S, Glover, B W, Hawkins, M P, Kimbell, G S, MacPherson, K A T, Merritt, J W, Milodowski, A E, Riley, N J, Robins, N S, Stone, P and Wingfield, R T R. 1997. The geology of the west Cumbria district. Memoir of the British Geological Survey, Sheets 28, 37 and 47 (England and Wales). 138pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable