The BGS Lexicon of Named Rock Units — Result Details

Stubton Limestones Bed

Computer Code: STBL Preferred Map Code: StL
Status Code: Full
Age range: Sinemurian Age (JS) — Sinemurian Age (JS)
Lithological Description: Group of two to four limestone beds separated by mudstone. Uppermost bed is typically brown and grey mottled, highly bioturbated, shelly, bioclastic, ferru-ooidal, packstone with numerous bored Gryphaea, weathering to orange brown, and 0.61m thick in the type section. Below are one to three thinner, non-ooidal argillaceous limestone beds. Rich fauna including forams, serpulids, corals, brachiopods, gastropods and ammonites. Forms a strong scarp feature with a dip slope.
Definition of Lower Boundary: Change up from bluish grey, shaly mudstone with numerous phosphatic nodules of uppermost 1m of the undifferentiated Beckingham Member; at 34.65m depth in type section Fulbeck Airfield Borehole F/B5 (SK95SW/17).
Definition of Upper Boundary: Change up into grey, mudstone of the undifferentiated Foston Member; at 33.51m depth in type section Fulbeck Airfield Borehole F/B5 (SK95SW/17).
Thickness: 1.0 to 2.4m; 1.14m in type section.
Geographical Limits: East Midlands: north Leicestershire to Lincolnshire. Not recognised in the Scunthorpe Mudstone Formation of north Lincolnshire, or south Leicestershire, where it passes south either into part of the more argillaceous Rugby Limestone Member of the Blue Lias Formation or into part of the mudstone-dominated Charmouth Mudstone Formation.
Parent Unit: Foston Member (FSTL)
Previous Name(s): Stubton Limestone (-2452)
Plungar Ironstone (-361)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Fulbeck Airfield Borehole F/B5 (SK95SW/17). 
Reference(s):
Brandon, A, Sumbler, M G and Ivimey-Cook, H C, 1990. A revised lithostratigraphy for the Lower and Middle Lias (Lower Jurassic) east of Nottingham, England. Proceedings of the Yorkshire Geological Society, Vol.48, 121-141. 
Sylvester-Bradley, P C and Ford, T D (editors), 1968. The Geology of the East Midlands. (Leicester: Leicester University Press.) 
Berridge, N G, Pattison, J, Samuel, M D A, Brandon, A, Howard, A S, Pharaoh, T C and Riley, N J. 1999. Geology of the Grantham district. Memoir of the British Geological Survey, sheet 127 (England and Wales). 
Carney, J N, Ambrose. K and Brandon A, 2002. Geology of the Melton Mowbray district - a brief explanation of the geological map. British Geological Survey Sheet Explanation, Sheet 142 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E127 E142 E126