Computer Code: |
SBSH |
Preferred Map Code: |
SBSh |
Status Code: |
Full |
Age range: |
Guadalupian Epoch (PUG)
— Lopingian Epoch (PUL) |
Lithological Description: |
Mainly red siltstones and silty mudstones, with some sandstone, millet-seed sand grains, mudstone breccias and gypsum. |
Definition of Lower Boundary: |
'The base of the main red clastic sequence', where red mudstones become predominant over the evaporites that characterise the underlying formation (St. Bees Evaporites). |
Definition of Upper Boundary: |
Taken where sandstone, which characterises the overlying formation (St. Bees Sandstone), becomes predominant over red siltstone and mudstone. |
Thickness: |
62m in type section with range of 0 - 215m in Cumbria generally. |
Geographical Limits: |
West and south Cumbria, north Lancashire, East Irish Sea Basin. |
Parent Unit: |
Cumbrian Coast Group (CCO)
|
Previous Name(s): |
St Bees Shales Formation [Obsolete Name and Code: Use SBSH]
(-1163)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Section |
Borehole NX91SE/190 (Sandwith S9) 1.4 km southwest of Salton Bay, west Cumbria. Depth 99.0 to 160.9 m (Arthurton and Hemingway, 1972). |
Reference(s): |
Arthurton, R S, and Hemingway, J E. 1972. The St Bees Evaporites - a carbonate evaporite formation of Upper Permian age in west Cumberland, England. Proceedings of the Yorkshire Geological Society, Vol. 38, 565-591. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E058
E018
E022
E011
S006
E028
E048
E012
|