| Computer Code: |
STRK |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Santonian Age (KS)
— Santonian Age (KS) |
| Lithological Description: |
Very hard, locally porcellanous, creamy white chalk, grainy in part with abundant sponge spicules. |
| Definition of Lower Boundary: |
The lower boundary is conformable at the change from soft white smooth chalk to very hard chalk. Placed within the higher part of the Seaford Chalk Formation. |
| Definition of Upper Boundary: |
The upper bounday is conformable at the top of the uppermost bed of very hard chalk. |
| Thickness: |
Not known in detail, estimated to be 2 to 3 m. Member might be one of a number of such beds of hard chalk between 5 and 10 m below the mapped base of the Newhaven Chalk Formation. |
| Geographical Limits: |
Occurs in the Winchester, Stockbridge area of Hampshire and westwards within the Bourne and Avon valleys near Salisbury. Central Hampshire and Wiltshire in the Southern Province. May extend northwards into Berkshire. |
| Parent Unit: |
Seaford Chalk Formation (SECK)
|
| Previous Name(s): |
Winchester Hardground [Obsolete Name and Code: Use STRK]
(-2459)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
Beech Farm, Nether Wallop (poor exposure in a silage pit). Type area only in the Stockbridge district. Ongoing research in progress but the unit is identified from its characteristic porcellanous limestone brash in the field. |
| Reference(s): |
| Hopson, P M, Farrant, A R, Newell, A J, Marks, R J, Booth, K A, Bateson, L B, Woods, M A, Wilkinson, I P, Brayson, J, and Evans, D J. 2007. Geology of the Salisbury district - a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. |
| Farrant, A R. 2000. Geology of the Dean and Wallops area, Hampshire and Wiltshire. Technical Report of the British Geological Survey, WA/00/11. |
| Booth, K A. 2002. Geology of the Winchester District - a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 299, Winchester (England and Wales). |
| Hopson, P M. 2005. A stratigraphical framework for the Upper Cretaceous Chalk of England and Scotland, with statements on the Chalk of Northern Ireland and the UK Offshore Sector. British Geological Survey Research Report RR/05/01 102pp. ISBN 0 852725175 |
| Farrant, A R. 1999. Geology of the Kings Somborne - Winchester district, Hampshire. Technical Report of the British Geological Survey, WA/99/06. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
