Triassic sandstone/Bowland Shale Formation and Craven Group separation map

Area where aquifer and shale/clay are present	Cheshire Derbyshire East Midlands Lancashire Lincolnshire West Cumbria Yorkshire Note that for the purposes of drafting this separation map the maximum depth of the Triassic sandstone aquifer is taken to be 400 mbgl based on the recommendations in the UK TAG report. More information about this can be found in the methods section
Thickness of intervening strata	Up to 5000 m Thinnest in south Midlands (south of Pennines), where the units locally overlie each other, and south Cumbria, where locally they are only separated by about 100 to 200 m of Permian mudstones and are adjacent across faults Thickest in Cheshire Basin: locally exceeds 4000 m East of Pennines: maximum about 2000 m
Lithology of intervening strata	West of Pennines: mixed permeability Millstone Grit Group and Pennine Coal Measures Group (mudstone, siltstone and sandstone); permeable Permian sandstone (principal aquifer); low permeability Permian mudstone (Cumbrian Coast Group) South Midlands: mixed permeability Millstone Grit Group and Pennine Coal Measures Group (mudstone, siltstone and sandstone) East of the Pennines: mixed permeability Millstone Grit Group and Pennine Coal Measures Group (mudstone, siltstone and sandstone); permeable Magnesian limestone (principal aquifer)
Other major aquifers in the area	West of the Pennines and south Midlands: Carboniferous limestone (below) East of the Pennines: Chalk; Lower Greensand; Spilsby Sandstone; Corallian limestone; Oolites (all above); Carboniferous limestone (below)
Other shales or clays in the area	East of Pennines: Kimmeridge Clay Formation; Ampthill Clay Formation; Kellaways Formation; Oxford Clay Formation; Osgodby Formation; Lias Group (all above)
Aquifer map	Triassic sandstone principal aquifer
Shale/clay map	Bowland Shale Formation and Craven Group shale/clay unit

ts-mg — Triassic sandstone/Bowland Shale Formation and Craven Group separation map. BGS © UKRI.

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