| Computer Code: |
RVS |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Courceyan Substage (CF)
— Holkerian Substage (CQ) |
| Lithological Description: |
The Ravenstonedale Group represents continental and peritidal facies. It comprises a typically thin succession, with geographically isolated outcrops present across parts of Cumbria.
Lithologically, the group includes green to green-grey and/or variably reddened pebble conglomerate (locally calcite cemented), lithic sandstone, sandstone and mudstone. Evaporitic deposits have been recorded in boreholes. Pedogenic carbonates occur within the sandstones, though they are less common than within the Kinnesswood Formation of the Inverclyde Group. Conglomerates have a local provenance, and basaltic lava flows occur locally within the alluvial fan facies. The most diverse lithological development is in the western part of the Stainmore Trough and northern part of the Askrigg Block.
Within the Stainmore Trough the group comprises the Pinskey Gill Marsett, Cockermouth Volcanic, Stone Gill Limestone and Shap Village Limestone formations (the last also occurring on the Alston block and in east Cumbria).
On the Askrigg Block the group comprises the Raydale Dolostone, Marsett and Penny Farm Gill formations.
In north, south and west Cumbria the group comprises the Marsett Formation.
On the isle of Man, the Langness Conglomerate Formation (formerly 'Basement Conglomerate') is tentatively referred to the group.
Within the Stainmore Trough it is Tournaisian in age. On the northern margin of the Askrigg Block it is Chadian to early Holkerian.
The on-lapping succession of the group was deposited within an epicontinental basin as alluvial fan, fluviodeltaic, marginal marine and peritidal deposits (Holliday et al., 1979).
Deposition on the Askrigg Block occurred following early Visean sea-level rise, with the succession located marginal to the more open marine conditions present in the Stainmore Trough at the time. Outside of the Stainmore Trough and northern part of the Askrigg Block the group is dominated by alluvial fan subfacies deposited within linked basins. |
| Definition of Lower Boundary: |
The group rests unconformably upon rocks ranging from Ordovician to Devonian in age, including the Wensleydale Granite beneath the Askrigg Block at Raydale. |
| Definition of Upper Boundary: |
Limestone formations at the base of the Great Scar Limestone Group (open marine, platform and ramp carbonates facies) define the top of the Ravenstonedale Group, though locally a nodular dolostone bed with rhizoliths, indicative of emergence, marks the top of the group on the Askrigg Block (Burgess, 1986). |
| Thickness: |
The Ravenstonedale Group is thickest in the western part of the Stainmore Trough (about 380 m) and northern part of the Askrigg Block (about 150 m). In south Cumbria, in the Duddon Estuary, it attains a maximum thickness of 240 m thinning appreciably towards the south and east. In north and east Cumbria the group is typically less than 35 m thick. |
| Geographical Limits: |
The Ravenstonedale Group occurs across Cumbria and north Yorkshire. |
| Parent Unit: |
Not Applicable (-)
|
| Previous Name(s): |
Ravenstonedale Limestone [Obsolete Name and Code: Use RVS]
(RSDL)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Ravenstonedale. |
| Reference(s): |
| 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.) |
| Burgess, I C. 1986. Lower Carboniferous sections in the Sedbergh district, Cumbria. Transactions of the Leeds Geological Association, Vol. 11, 1-23. |
| Holliday, D W, Neves, R, and Owens, B. 1979. Stratigraphy and palynology of early Dinantian (Carboniferous) strata in shallow boreholes near Ravenstonedale, Cumbria. Proceedings of the Yorkshire Geological Society, Vol. 42, 343-356. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E040
|
