The BGS Lexicon of Named Rock Units — Result Details
Haddenham Formation
| Computer Code: | HADD | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Tithonian Age (JI) — Tithonian Age (JI) | ||
| Lithological Description: | Fossiliferous marine limestones and lagoonal limestones together with calcareous and commonly glauconitic, sandstones and sands. | ||
| Definition of Lower Boundary: | Upwards change from fully marine limestones with large molluscan fossils of the Portland Stone Formation (Portland Group) to lagoonal fine-grained limestones and marls of the Haddenham Formation (Purbeck Limestone Formation on BGS maps), the base of which is commonly marked either by laminated, ostracod-bearing or oyster-bearing marl, or by a sharp non-sequential junction. | ||
| Definition of Upper Boundary: | Overlain unconformably by generally non-calcareous and commonly ferruginous sands and sandstones of the Lower Greensand or Whitchurch Sand Formation, or by calcareous mudstones of the Gault Formation. | ||
| Thickness: | Up to 13m thick. | ||
| Geographical Limits: | Outliers from Swindon, in north Wiltshire, through Oxfordshire to Aylesbury in Buckinghamshire, and possibly an outlier in the Vale of Pewsey near Devizes, though this is currently rather poorly known (Wimbledon, 1980). | ||
| Parent Unit: | Purbeck Group (PB) | ||
| Previous Name(s): | Portland Beds
(-948)
Purbeck Limestone Formation [Obsolete Name and Code: Use PB, HADD] (-2229) Purbeck Limestone [Obsolete Name and Code: Use HADD] (-1583) Portland Formation [Obsolete Name and Code: Use HADD, PL] (*931) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Section | BGS Hartwell Borehole SP71SE/1 [7926 1223]. Surface to 5.16m depth. | ||
| Reference Section | Bugle Pit [SP 794 121], Hartwell. The original pit exposed most of the succession with a small adjacent section [SP7932 1205] being preserved as an SSSI. | ||
| Type Area | Thame to Aylesbury area. | ||
| Reference(s): | |||
| Horton, A, Sumbler, M G, Cox, B M and Ambrose, K, 1995. Geology of the country around Thame. Memoir of the British Geological Survey, Sheet 237 (England and Wales). | |||
| Townson, W G. 1975. Lithostratigraphy and deposition of the type Portlandian. Journal of the Geological Society, London, Vol. 131, 619-638. | |||
| Wimbledon, W A and Cope, J C W. 1978. The ammonite faunas of the English Portland Beds and the zones of the Portlandian Stage. Journal of the Geological Society of London, Vol.135, 183-190. | |||
| Cox, B M, Gallois, R W, and Sumbler, M G. 1994. The stratigraphy of the BGS Hartwell Borehole, near Aylesbury, Buckinghamshire. Proceedings of the Geologists' Association, Vol. 105, 209-224. | |||
| Arkell, W J. 1935. The Portlandian Beds of the Dorset mainland. Proceedings of the Geologists' Association, Vol. 46, 301-347. | |||
| Blake, J F. 1880. On the Portland Rocks of England. Quarterly Journal of the Geological Society of London, Vol. 36, 189-236. | |||
| Wimbledon, W A. 1976. The Portland Beds (Upper Jurassic) of Wiltshire. Wiltshire Archaeological and Natural History Magazine, Natural History, Vol.71, 3-11. | |||
| Wimbledon, W A. 1980. Portlandian correlation chart. 85-93 in Cope, J C W (Editor), A correlation of the Jurassic rocks of the British Isles. Part Two: Middle and Upper Jurassic. Geological Society of London Special Report, No.15. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| none recorded or not applicable | |||