The BGS Lexicon of Named Rock Units — Result Details
Arngrove Spiculite Member
| Computer Code: | AGSP | Preferred Map Code: | AnS |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Oxfordian Age (JO) — Oxfordian Age (JO) | ||
| Lithological Description: | Pale grey, siliceous or calcareous sandstone or siltstone with abundant siliceous spicules of Rhaxella perforata (tetractinellid sponge). | ||
| Definition of Lower Boundary: | An upward transition from the silty mudstones of the West Walton Formation or locally, fine-grained silty sands and clayey silts of the Temple Cowley Member of the Kingston Formation to coarser-grained, spiculitic sandstone. | ||
| Definition of Upper Boundary: | An upward transition from spiculitic sand or sandstone, to non-spiculitic sand and calcareous sandstone of the Beckley Sand Member of the Kingston Formation, or marls and limestones of the Oakley Member of the Stanford Formation. | ||
| Thickness: | Up to 4.2 m thick. | ||
| Geographical Limits: | The area between Beckley, Wheatley and Brill north-east of Oxford as seen on the 1:50 000 sheet 237 (inset map), and passes south-westwards into the Temple Cowley Member. Restricted to sheet 237, although similar spiculites are present in the Purton area (sheet 252). | ||
| Parent Unit: | Kingston Formation (KTON) | ||
| Previous Name(s): | Rhaxella Chert [Obsolete Name And Code: See RIS]
(RCH)
Arngrove Stone [Obsolete Name and Code: Use AGSP] (-3158) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | Brill No. 1 Borehole (SP61SE/10) 106.06 - 107.70 m. | ||
| Type Area | Arngrove Farm (now Old Arngrove), near Brill, Bucks. | ||
| Reference Section | M40 Borehole 10 (SP60NW/6), 10.20 - 13.68 m. | ||
| 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). | |||
| Cox, B M, and Wright, J K. 2001. British Upper Jurassic stratigraphy (Oxfordian to Kimmeridgian). Geological Conservation Review Series, No. 21. (Peterborough: Joint Nature Conservation Committee.) | |||
| Davies, A M. 1907b. Excursion to Dorton, Brill and Arngrove. Proceedings of the Geologists' Association, Vol. 20, 183-186. | |||
| Arkell, W J. 1927. The Corallian rocks of Oxford, Berkshire and north Wiltshire. Philosophical Transactions of the Royal Society of London, Vol. B216, 67-181. | |||
| Wright, J K and Cope, J C W. In press. Oxfordian - Kimmeridgian Correlation Chart. In: A correlation of Jurassic rocks in the British Isles: Middle and Upper Jurassic. Cope, J C W (editor). Special Report of the Geological Society of London. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E237 | |||