Corallian Limestone/Lias separation map

Area where both aquifer and shale are present

North Yorkshire and southern England.

Note that for the purposes of drafting this separation map the maximum depth of the Corallian aquifer is taken to be 400 m below ground level based on the recommendations in the UK TAG report (UK TAG, 2011). More information about this can be found in the methods section.

Thickness of intervening strata

North Yorkshire: about 50 to 300 m.

Southern England: about 100 to 500 m.

Lithology of intervening strata

North Yorkshire: permeable Ravenscar Group and low permeability Kellaways, Oxford Clay and Osgodby Formations (clays).

Southern England: permeable Oolites (principal aquifer) and low permeability Kellaways, Oxford Clay and Osgodby Formations (clays).

Other major aquifers in the area

North Yorkshire: Chalk (above), Triassic sandstones (below), Magnesian limestone (below) and Carboniferous Limestone (below).

Southern England: Chalk (above), Lower Greensand (above), Triassic sandstones (below), Permian sandstones (below) and Carboniferous Limestone (below).

Other shales or clays in the area

North Yorkshire: Kimmeridge and Ampthill Clays (above) and Bowland and Craven Groups (below).

Southern England: Kimmeridge and Ampthill Clays (above).

Links to aquifer and shale/clay maps

View the map of the Corallian principal aquifer.

View the map of the Lias.

References

UK TAG. 2011. Defining and reporting on groundwater bodies. UK Technical Advisory Group on the Water Framework Directive, working paper V6.21/Mar/2011