The BGS Lexicon of Named Rock Units — Result Details

Ardley Member

Computer Code: ARDY Preferred Map Code: WhL
Status Code: Full
Age range: Mid Jurassic Epoch (JM) — Bathonian Age (JN)
Lithological Description: A pale grey to off-white or yellowish limestone, peloidal wackestones and packstones with common ooidal and shell fragmental grainstones, particularly to the southwest of the type area, also recrystallised limestone with beds of argillaceous limestone, sandy limestone, marl and mudstone or clay at some levels.
Definition of Lower Boundary: Generally sharp, erosive boundary, with sandy mudstone or sandy limestone ('Roach Bed') overlying Excavata Bed (peloidal packstone) at the top of the Shipton Member.
Definition of Upper Boundary: Sharp, eroded and commonly with a hardground top surface of pale grey to white wackestone of the Bladonensis Bed at the top of the Ardley Member, overlain by clay/mudstone marl/limestone of the Bladon Member or the Signet Member, else where these are absent, with a sharp, erosive boundary with cross-bedded shell-fragmental ooidal limestone, or mudstone of the Forest Marble Formation. In the northeast, it is believed to be overlain directly by the Blisworth Clay Formation.
Thickness: From 6 m to 10 m thickness - generally increasing thickening to the southwest, and about 7m thick in the type section.
Geographical Limits: Stroud to Cirencester area of Gloucestershire where it passes south-westwards into the Athelstan Oolite Formation, northeastward through Oxon ando Buckinghamshire to the Brackley area, where it arbitarily passes north-east into the Blisworth Limestone Formation. Restricted to Sheets 217, 218, 219, [234]. 235, 236, 237.
Parent Unit: White Limestone Formation (WHL)
Previous Name(s): Ardley Beds And Bladon Beds (-20)
Upper Part: Ardley Beds (-651)
Alternative Name(s): none recorded or not applicable
Reference Section  Primary reference section: Shipton-on-Cherwell Quarry. Arkell, W J, 1931; Barker, M J, 1976; Palmer, T J, 1979; Richardson, L, et al, 1946; Sumbler, M G, 1984; Cox, B M, and Sumbler, M G. 2002. See Sumbler, M G, 1984 for additional reference sections. 
Type Area  Cherwell Valley,north of Oxford (Woodstock to Ardley) Palmer,1979 
Type Section  Ardley Railway cutting and quarry. Arkell, W J, et al, 1933; Palmer, T J, 1973; Barker, M J, 1976; Sumbler, M G, 1984; Cox, B M, and Sumbler, M G. 2002. 
Sumbler, M G, 1984. The stratigraphy of the Bathonian White Limestone and Forest Marble formations of Oxfordshire. Proceedings of the Geologists' Association, Vol.95, 51-64. 
Arkell, W J, 1931. The Upper Great Oolite, Bradford Beds and Forest Marble of south Oxfordshire, and the succession of gastropod faunas in the Great Oolite. Quarterly Journal of the Geological Society of London, Vol.87,p. 563-629. 
Arkell, W J, Richardson, L and Pringle, J, 1933. The Lower Oolites exposed in the Ardley-Fritwell railway cuttings, between Bicester and Banbury, Oxford. Proceedings of the Geologists' Association, Vol.44, 340-354. 
Barker, M J, 1976. A stratigraphical, palaeoecological and biometrical study of some English Bathonian gastropoda (especially Nerinacea). (University of Keele: Unpublished PhD thesis). 
Palmer, T J, 1979. The Hampen Marly and White Limestone formations: Florida-type carbonate lagoons in the Jurassic of central England. Palaeontology, Vol.22, 189-228. 
Richardson, L, Arkell, W J and Dines, H G. 1946. Geology of the country around Witney. Memoir of the Geological Survey of Great Britain. Sheet 236 ( England and Wales). 
Cox, B M and Sumbler, M G. 2002. British Middle Jurassic Stratigraphy. Geological Conservation Review Series No.26. [Peterborough: Joint Nature Conservation Committee.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E235 E217 E219 E236 E237 E218 E234