The BGS Lexicon of Named Rock Units — Result Details

Hampen Formation

Computer Code: HMB Preferred Map Code: Hm
Status Code: Full
Age range: Bathonian Age (JN) — Bathonian Age (JN)
Lithological Description: Limestones with subordinate interbedded marls; limestones characteristically grey to brown, thinly bedded, fine- to very fine-grained, well-sorted, ooidal grainstone to packstone, commonly slightly sandy or silty, with small-scale cross-bedding.
Definition of Lower Boundary: Limestone and marl (as in Lithological Description), resting sharply on cross-bedded coarse-grained ooidal grainstone of the Taynton Limestone Formation or on mudstone/sandy limestone of the Fuller's Earth Formation.
Definition of Upper Boundary: More or less sharp boundary with purer, off-white or yellowish peloidal packstone, wackestone or grainstone of the White Limestone Formation.
Thickness: c.4-11m; 8.96m at type locality.
Geographical Limits: c.Frome Valley, west of Cirencester (where passes it into the upper part of "Througham Tilestones"/Dodington Ash Rock) eastwards to Oxford-Brackley area (where it passes into the Rutland Formation).
Parent Unit: Great Oolite Group (GOG)
Previous Name(s): MARLY BEDS
Alternative Name(s): none recorded or not applicable
Type Section  Hampen [Railway] Cutting SSSI, near Salperton, Gloucester, c.11km west of Bourton-on-the-Water. 
Reference Section  Chedworth Station Railway Cutting. 
Reference Section  Daglingworth Quarry. 
Sumbler, M G and Barron, A J M, 1996. The type section of the Hampen Formation (Middle Jurassic, Great Oolite Group) at Hampen Cutting, Gloucestershire. Proceedings of the Cotteswold Naturalists' Field Club, Vol.40, 118-128. 
Arkell, W J. 1933. The Jurassic System in Great Britain. [Oxford: Clarendon Press.] 
Cope, J C W (Editor) 1980b. A correlation of Jurassic rocks in the British Isles. Part Two: Middle and Upper Jurassic. Geological Society of London Special Report, No.15 
Cox, B M, and Sumbler, M G. 2002. British Middle Jurassic stratigraphy. Geological Conservation Review Series, Vol.26. (Peterborough: Joint Nature Conservation Committee.) 
McKerrow, W S and Kennedy, W J, 1973. The Oxford district. Geologists' Association Guide No.3 
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. 1911. On the sections of the Forest Marble and Great Oolite on the railway between Cirencester and Chedworth, Gloucestershire. Proceedings of the Geologists' Association, Vol.22, 95-115. 
Sumbler, M G and Barron, A J M, 1995. Geological notes and local details for 1: 10 000 Sheet SP01SE (Chedworth). British Geological Survey Technical Report, WA/95/73. 
Sumbler, M G, Barron, A J M and Morigi, A N, 2000. Geology of the Cirencester district. Memoir of the British Geological Survey, Sheet 235 (England and Wales). 
Wyatt, R J. 1996. A correlation of the Bathonian (Middle Jurassic) succession between Bath and Burford, and its relation to that near Oxford. Proceedings of the Geologists' Association, Vol.107, 299-322. 
Sumbler, M G. 1999. Correlation of the Bathonian (Middle Jurassic) succession in the Minchinhampton-Burford district; a critique of Wyatt (1996). Proceedings of the Geologists' Association, Vol.110(1), 53-64. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E235 E236 E252 E217