| Computer Code: |
AFS |
Preferred Map Code: |
AfS |
| Status Code: |
Full |
| Age range: |
Arundian Substage (CJ)
— Arundian Substage (CJ) |
| Lithological Description: |
The Ashfell Sandstone Formation comprises thick-bedded, fine-grained sandstone with current ripple laminations, rare cross-bedding, and convolute bedding. Interdigitating are beds of marine mudstone and thin limestone with shelly faunas.
Fluviodeltaic. Late Arundian. |
| Definition of Lower Boundary: |
The base of the formation overlying the Breakyneck Scar Limestone Formation cannot be defined precisely due to poor exposure. |
| Definition of Upper Boundary: |
The top of the formation conformably underlies the mainly packstone, shelly grainstone or lime mudstone of the Ashfell Limestone Formation in the Stainmore Trough and Shap, east Cumbria, and the mainly biomicrosparites and biomicrites of the Fawes Wood Limestone Formation on the Askrigg Block. |
| Thickness: |
The formation is 152 m thick in the Ravenstonedale area, thinning northwards. In the Raydale Borehole (BGS Registration Number SD98SW/1) [SD 9026 8474] it is 38.40 m thick. In the Appleby district it is 20-40 m thick. |
| Geographical Limits: |
The formation extends from the edge of the Lake District to the Alston Block, including the Eden Valley and northern margin of the Stainmore Trough. |
| Parent Unit: |
Great Scar Limestone Group (GSCL)
|
| Previous Name(s): |
Ashfell Sandstone [Obsolete Name and Code: Use AFS]
(-2559)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
The longest and most complete section through the formation is along the Scandal Beck in the Ravenstonedale area, where up to 160 m of sandstone with four limestone interbeds occurs (see Pattison, 1990; Dunham and Wilson, 1985). |
| Reference(s): |
| Turner, J S. 1959. Pinksey Gill beds in the Lune Valley, Westmoreland, and Ashfell Sandstone in Garsdale, Yorkshire. Transactions of the Leeds Geological Association, Vol.7, 78-87. |
| Turner, J S. 1950. Notes on the Carboniferous Limestone of Ravenstonedale, Westmoreland. Transactions of the Leeds Geological Association, Vol.6, 124-134. |
| Dunham, K C, and Wilson, A A. 1985. Geology of the Northern Pennine Orefield. Volume 2 Stainmore to Craven. Economic Memoir of the British Geological Survey, Sheets 40, 41 and 50, and parts of Sheets 31, 32, 51, 60 and 61(England and Wales). |
| Dean, M T, Browne, M A E, Waters, C N and Powell, J H. 2011. A lithostratigraphical framework for the Carboniferous successions of northern Great Britain (onshore). British Geological Survey Research Report, RR/10/007. 165pp. |
| Waters, C N, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) |
| Garwood, E J. 1913. The Lower Carboniferous succession in the north-west of England. Journal of the Geological Society, London, Vol.68 (for 1912), 449-586. |
| Millward, D, McCormac, M, Hughes, R A, Entwisle, D C, Butcher, A, and Raines, R G. 2003. Geology of the Appleby district – a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 30 Appleby (England and Wales). |
| Mitchell, M, Taylor, B J and Ramsbottom, W H C, 1978. Carboniferous, 168-188 in The geology of the Lake District. Moseley, F (editor). Yorkshire Geological Society Special Publication. No.3. |
| Pattison, J. 1990. Geology of the Orton and Sunbiggin Tarn districts. Geological notes and local details for 1:10,000 Sheets NY60NW and NY60NE and part of 1:50,000 Sheets 30 (Appleby), 31 (Brough), 39 (Kendal) and 40 (Kirkby Stephen). British Geological Survey Onshore Geology Series, Technical Report, WA/90/12. |
| Ramsbottom, W H C. 1973. Transgressions and regressions in the Dinantian: A new synthesis of British Dinantian stratigraphy. Proceedings of the Yorkshire Geological Society, Vol.41, 261-291. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E040
E031
|
