| Computer Code: |
RIS |
Preferred Map Code: |
notEntered |
| Status Code: |
Pending Upgrade |
| Age range: |
Oxfordian Age (JO)
— Oxfordian Age (JO) |
| Lithological Description: |
Pale grey to brownish grey sandstone, mainly composed of abundant siliceous spicules of Rhaxella perforata (tetractinellid sponge), with scattered ferruginous ooids. Notably low density (highly porous?). Weathers in soil to angular blocks |
| Definition of Lower Boundary: |
Base is a change up from interbedded yellowish fine quartz sand, clayey in parts and locally cemented into calcareous sandstone, and sandy mudstone of undifferentiated Hazelbury Bryan Formation into grey sandstone with siliceous sponge spicules of the Ringsbury Spiculite Member. |
| Definition of Upper Boundary: |
The top is a change up from grey sandstone with siliceous sponge spicules of Ringsbury Spiculite Member, into interbedded yellowish fine quartz, calcareous sandstone, and sandy mudstone of undifferentiated Hazelbury Bryan Formation or, where absent, into bedded, finely bioclastic limestone of the Stanford Formation. |
| Thickness: |
0 to 6m |
| Geographical Limits: |
Area between Purton and Wootton Bassett, Wiltshire. Pinches out laterally into undifferentiated Hazelbuty Bryan Formation. May be lateral equivalent of the Arngrove Spiculite Member of the Kingston Formation of east Oxfordshire. |
| Parent Unit: |
Hazelbury Bryan Formation (HYB)
|
| Previous Name(s): |
Rhaxella Chert [Obsolete Name And Code: See RIS]
(RCH)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Ringsbury Camp, Purton, Wiltshire |
| Partial Type Section |
Quarry 830m westsouthwest of Purton Church. Arkell, 1941. |
| Reference(s): |
| British Geological Survey. 1974. Swindon. England and Wales Sheet 252. Solid and Drift. 1:63 360. (Southampton: Ordnance Survey for British Geological Survey.) |
| Arkell, W J. 1941. Map of the Corallian Beds around Purton, Wiltshire. Wiltshire Archaeological and Natural History Magazine, Vol. 49, 274-282. |
| 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: |
|
E252
|
