| Computer Code: |
WIT |
Preferred Map Code: |
Wit |
| Status Code: |
Full |
| Age range: |
Asturian Substage (CAS)
— Stephanian Stage (CS) |
| Lithological Description: |
Red bed sequence; mudstone-dominated in lower part but increasingly arenaceous towards top. Thin Spirorbis limestones at some levels. Impersistent conglomerates in uppermost part. |
| Definition of Lower Boundary: |
Transitional. Defined in the field at the upwards change from grey measures of the Halesowen Formation to red beds. Defined on geophysical logs (in uncored boreholes) above a narrow zone of high gamma radiation. |
| Definition of Upper Boundary: |
At the top of highest mappable sandstone unit (Arley and Exhall sandstones) beneath the basal argillaceous beds of the overlying Keresley Member. |
| Thickness: |
Range 280 - 357m; mean 334m; based on geophysical well log data. |
| Geographical Limits: |
Warwickshire Coalfield (northern part) Sheet 169. Also likely to extend in the subcrop across the southern part of the Warwickshire Coalfield (Sheet 184). |
| Parent Unit: |
Salop Formation (SAL)
|
| Previous Name(s): |
Includes Coventry Sandstone, (Lower Part)
(-610)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Warwickshire Coalfield between Over Whitacre and Baxterley (poor exposures). |
| Reference Section |
Birch Tree Farm Borehole (SP38SW/161). Top of Member (uncored) taken at 238m below surface. Base at 519.5m below surface. |
| Reference Section |
Old quarry at Tipper's Hill Lane exposes granule to pebble grade breccio-conglomerates composed primarily of mudstone clasts. Typifies lower part of member. |
| Reference(s): |
| Powell, J H, Chisholm, JI, Bridge, D M, Rees, J G, Glover, B W and Besly, B M. 2000. Stratigraphical framework for Westphalian to Early Permian red-bed successions of the Pennine Basin. British Geological Survey Technical Report WA/99/10. |
| Bridge, D M, Carney, J N, Lawley, R S, and Rushton, A W A. 1998. Geology of the country around Coventry and Nuneaton. Memoir of the British Geological Survey, Sheet 169 (England and Wales). |
| Eastwood, T, Gibson, W, Cantrill, T C, and Whitehead, T H. 1923. The geology of country around Coventry, including an account of the Carboniferous rocks of the Warwickshire Coalfield. Memoir of the Geological Survey of Great Britain, Sheet 169. (England and Wales). |
| Old, R A, Sumbler, M G and Ambrose, K, 1987. Geology of the country around Warwick. Memoir of the British Geological Survey, Sheet 184 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E169
E154
|
