Bedrock Sandstone channel subsurface mapping for the Gateshead area - Project Groundwater Northumbria

Kearsey, T.; Callaghan, E.; Arkley, S.; Reeves, T.. 2025 Bedrock Sandstone channel subsurface mapping for the Gateshead area - Project Groundwater Northumbria. Nottingham, UK, British Geological Survey, 29pp. (Project Groundwater Northumbria series, CR/24/080N) (Unpublished)

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Abstract/Summary

This report has been produced by the British Geological Survey (BGS) on behalf of Project Groundwater Northumbria, the Flood and Coastal Resilience Innovation Programme (FCRIP) project led by Gateshead Council. It provides background and methodological information on the development of maps of the possible locations of major bedrock sandstone channels in the subsurface for the Gateshead area. The development of these maps was undertaken through the analysis of 139 boreholes logs which were coded for the project along with mine plan information and academic literature. An analysis of all the borehole data coded for the project shows that 41% of the rock recorded in the borehole logs in boreholes were sandstone in the Lower and Middle Pennine Coal Measures formations. The median thickness of sandstone is 2.1 m, which is to say half of the sandstones are below that thickness. Using the deposit thickness interpreted by Fielding (1986) it is possible to suggest that 70-80 % of the sandstones are in sandstone bodies with a width <400 m rather than in major channels. This would suggest that sandstones are present even in the areas where no major sandstone channel has been mapped based on the distribution and thicknesses seen in borehole. The number and distribution of major distributary channel sandstones varies significantly between coal seams. Above the High Main Coal and above the Durham Low Main Coal there are extensive channel sandstones across the whole area. This may suggest that the channels have amalgamated into channel belts at these levels. Through most of the stratigraphic slices the sandstones are in beds <10m thick which is too thin to assume that they are associated with the major distributary channels. There is a high degree of uncertainty with all major distributary channel sandstones mapped because it is impossible to positively identify the facies in the borehole data due to the age and method of borehole logging. It is suggested that the maps cannot be used to identify where specific sandstones are underground or indicate areas of mudstone. Also, they should not be used in any flow simulations without accounting for the fact that there are more, but smaller sandstones in the areas that are not part of channels. The mapped sandstone bodies comprise only 10% of the total sandstone within the rock volume, indicating that fluid flow will also occur in areas beyond the mapped sandstones.

Item Type:	Publication - Report (Project Report)
Funders/Sponsors:	British Geological Survey, Department of Environment, Food and Rural Affairs (Defra)
Additional Information. Not used in RCUK Gateway to Research.:	This item has been internally reviewed, but not externally peer-reviewed.
NORA Subject Terms:	Earth Sciences
Date made live:	26 Feb 2025 12:24 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/538962

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