The BGS Lexicon of Named Rock Units — Result Details

Spilsby Sandstone Formation
Computer Code: SYS Preferred Map Code: SyS
Status Code: Full
Age range: Tithonian Age (JI) — Valanginian Age (KV)
Lithological Description: The Formation comprises two members that are further divided: Upper Spilsby Sandstone Member. Thin, coarse-grained, grey or brown pebble sandstone with iron ooliths [Ferruginous Grit of Swinnerton, 1937]. Underlain by fine-to medium-grained, buff, yellow and white sands with sparse calcareous "doggers" [the upper part of Swinnerton's 1937, "Glauconitic Sands"]. The latter sands become coarser and greener towards the base of the Member. A bed of phosphatic nodules and small [generally chert] pebbles occurs at the base [the Mid Spilsby Nodule Bed of Casey [1963, 1973]. Lower Spilsby Sandstone Member. Coarse-grained, pebbly, glauconitic sands and sandstones with calcareous "doggers" and sporadic phosphatic nodules towards the Top [this unit equates with the lower part of Swinnerton's, 1937, "Glauconitic Sands"]. The base of the Member comprises a thin grey sandstone with phosphatic nodules [the "Basement Beds" of Swinnerton, 1937, and Beds A and D of Swinnerton, 1935.
Definition of Lower Boundary: A downsection change from grey sandstone with phosphatic nodules [the "Basement Beds" of the Lower Spilsby Sandstone Member] to mudstone of the Kimmeridge Clay Formation.
Definition of Upper Boundary: Down-section change from purple-grey and brown mottled mudstones with sporadic iron ooliths [Hundlsby Clay Member, Claxby Ironstone Formation] or argillaceous oolitic ironstone [Claxby Ironstone Formation] to pale yellow, medium-grained sand and sandstone [Upper Spilsby Sandstone Member]. Offshore in the Southern North Sea Basin, the upper boundry is recognised by a down-section change from calcareous mudstones [Valhall Formation] to sandstones. It corresponds to a reduction in gamma-ray values and increase in sonic log.
Thickness: To c.24m
Geographical Limits: Onshore, the Spilsby Sandstone Formation is restricted to the southern part of Lincolnshire. It extends offshore into The Wash, but its extent is unknown as within a short distance it passes laterally into the lower part of Sandringham Sand Formation [Wingfield et al., 1978]. Offshore in the Southern North Sea, the Formation has been recognized in quadrants 47, 48, and 51-54. In the offshore region it forms the basal part of the Cromer Knoll Group [Lott and Knox, 1994]. It is not clear how the Spilsby Sandstone Formation [offshore] relates to the Spilsby Sandstone Formation and the Sandringham Sand Formation [onshore].
Parent Unit: Cromer Knoll Group (CRKN)
Previous Name(s): Spilsby Beds Of Spilsby Series (-4915)
Spilsby Sandstone (-3066)
Lower Sand And Sandstone (*596)
Greensand And Sandstone (-556)
Alternative Name(s): Lower Sand And Sandstone
Stratotypes:
Reference Section  Skegness Borehole between the depths 107.37 and 116.8m. 
Reference Section  Boston Corporation Waterworks, Fordington, boreholes, 8km north of Spilsby. Swinnerton, 1935, emended by Casey, 1973. 
Reference Section  Railway cutting between Benniworth and Donnington-on-Bain Casey, 1973 
Reference Section  Nettleton Top Barn, southwest of Caistor. Casey, 1973 
Reference(s):
Judd, J W 1867. On the strata which form the base of the Lincolnshire Wolds. Quarterly Journal of the Geological Society, London, 23, 227-251. 
Strahan, A 1886. Notes on the relations of the Lincolnshire Carstone. Quarterly Journal of the Geological Society, London, 42, 481-493. 
Swinnerton, H H 1935. The rocks below the Red Chalk of Lincolnshire and their cephlopod fauna. Quarterly Journal of the Geological Society, London, 91, 1-46. 
Swinnerton, H H. 1937 [for 1963]. A monograph of British Cretaceous Belemnites, Part 11. Monograph of the Palaeontographical Society. 
Casey, R. 1963. The dawn of the Cretaceous period in Britain. Bulletin of the South East Union of Scientific Societies, 117, 1-15. 
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.] 
Dikes, W H and Lee, J W. 1837. Outlines of the Geology of Nettleton Hill, Lincolnshire. The Magazine of Natural History, I [No.11], 562-566. 
Lott, G K and Knox, R W O'B. 1994. 7. Post Triassic of the Southern North Sea. In: Lithostratigraphic nomenclature of the UK North Sea. Knox, R W O'B and Cordey, W G. (editors) (BGS, Nottingham). 
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. 
Jukes-Browne, A.J. 1887. The Geology of part of east Lincolnshire. Memoir of the Geological Survey of the United Kingdom, 181pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E129 E103 E081 E089 E090 E091 E115
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