The BGS Lexicon of Named Rock Units — Result Details

Leziate Member

Computer Code: LZB Preferred Map Code: LzB
Status Code: Full
Age range: Valanginian Age (KV) — Valanginian Age (KV)
Lithological Description: Incoherent, moderately clean, pale grey (locally green, yellow or orange), fine- to medium-grained, cross-bedded quartz sands with subordinate bands of silt or clay. Pyrite nodules are present and glauconite is locally abundant.
Definition of Lower Boundary: The base is taken at the up-section change from glauconitic, clayey, grey and green sands with bands and "doggers" of brown-weathering clay-ironstone and seams of phosphatic nodules (Mintlyn Sands Member) to incoherent, moderately clean, pale grey (locally green, yellow or orange), fine- to medium-grained, cross-bedded quartz sands with subordinate bands of silt or clay (Leziate Member).
Definition of Upper Boundary: In the King's Lynn district, the upper boundary is defined by an up-section change from incoherant, moderately clean, pale grey (locally green, yellow or orange), fine- to medium-grained, cross-bedded quartz sands with surbordinate bands of silt or clay into thinly bedded, fine-grained, silty sands and sandstones (Dersingham Formation). Locally the sands of the Leziate Member are overlain by mid to dark grey clay (?Snettisham Clay) (Gallois, 1994). In the Gayton-Marham area, pebbly, ferruginous sandstones (Carstone Formation) overstep the incoherant, moderately clean, pale grey Leziate Member.
Thickness: Up to 30m.
Geographical Limits: The Leziate Member occurs in boreholes in The Wash and in Norfolk, and extends from Heacham southwards to Denver. North of King's Lynn it forms a steep feature capped by the sandstones of the Dersingham Formation, but south of King's Lynn, the feature is subdued beneath the Carstone. The Leziate Member occurs in the heathland areas of Dersingham Heath, Sandringham Warren, Roydon Common, Leziate Heath and Shouldham Warren. It is known from a number of boreholes in western Norfolk, including the Hunstanton and Gayton boreholes. It passes into the Claxby Formation to the northwest.
Parent Unit: Sandringham Sand Formation (SAS)
Previous Name(s): Leziate Sand Member (-2931)
Leziate Beds (-1678)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Hunstanton Borehole TF64SE/11 [TF 6857 4078] between 65.02 and 87.02m depth. Where the member is encountered between 65.02 and 87.02m depth. 
Reference Section  Gayton Borehole TF71NW/10 [TF 7280 1974] Where the full succession was encountered between 32.6 and 63.98 m depth. 
Partial Type Section  Bawsey Warren. Up to 8.6m of the lower part of the member were exposed in the quarry of the former Bawdsey Brickworks. Gallois (1994, p.80). 
Reference Section  Composite section in a railway cutting adjacent to Locke Farm. Where the uppermost 1.5m of the Leziate Member is exposed beneath the Dersingham Formation. Gallois (1994, p.78). 
Partial Type Section  Former sand pits (often refered to as the Leziate Sand Pits). The middle and upper part of the member is exposed in a series of pits with widely spaced sections between [TF 6765 1912 and 6882 1954]. A composite section [TF 6843 1935] on the north side of the road at Brow of the Hill exposes about 29m of the member . See Gallois (1994, p.80). 
Reference Section  BGS Wash Borehole IGS 72/77B [TF 6313 4835] Wingfield et al. 1978; 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. 1984. The Late Jurassic to Mid Cretaceous rocks of Norfolk. Bulletin of the Geological Society of Norfolk, Vol.34, 3-64. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E129 E145 E146 E159 E160