Geological characterisation of the area around the Glasgow Geothermal Energy Research Field Site

The Glasgow Geothermal Energy Research Field Site is located on the western side of the Central Coalfield of the Midland Valley of Scotland. It is located within glacial and post-glacial Quaternary superficial deposits, overlain by a variable thickness of artificial (made) ground. These deposits rest on approximately 300 m of Scottish Coal Measures Group bedrock. Underlying this are older Carboniferous strata of the hundreds of metres thick Clackmannan and Strathclyde groups. The prior industrial land use has left a legacy of abandoned, flooded mine workings and a variety of artificial ground forming the current land surface.

The following sections give a brief description of the geology in the area.

Quaternary Geology

A complex succession of Quaternary superficial deposits covers the research area, including widespread glacial till and marine, lacustrine and fluvio-glacial deposits, overlain by fluvial deposits, recent alluvium and anthropogenic (man-made) deposits.

The Quaternary deposits are of variable thickness, up to 30 m. The upper surface of bedrock was incised, with thicker accumulations of superficial deposits infilling a broadly NW-SE trending channel following the modern day River Clyde. There is widespread made, filled and landscaped ground relating to a variety of prior industrial land use, in some places this is 10-15 m thick.

Code Equivalent description on 1: 10, 000 scale published map
Water Unattributed polygons
Made Ground Made Ground, Made Ground and Worked Ground, Infilled Ground
Peat Peat – blanket or basin peat, Flandrian
Law Sand and Gravel Member Alluvium – modern river floodplains – located along the upper reaches and tributaries to the River Clyde, Flandrian. Also includes some Alluvial Fan Deposits, Flandrian and some River Terrace Deposits, Flandrian.
Gourock Sand Member Marine Deposits – located along the lower reaches of the River Clyde, Flandrian and Alluvium – modern river floodplains – along the upper reaches of the River Clyde, Flandrian
Killearn Sand and Gravel Member Generally Raised Marine Deposits, Devensian, Raised Marine Deltaic Deposits, Devensian or Raised Marine Intertidal and Subtidal Deposits, Devensian
Paisley Clay Member Generally Raised Marine Deposits, Devensian or Raised Marine Intertidal and Subtidal Deposits, Devensian
Bridgeton Sand Member Largely concealed beneath younger deposits, where present, exposures usually represented as Raised Marine Deposits, Devensian
Ross Sand Member Glaciolacustrine Deposits, Devensian Glaciolacustrine Deltaic Deposits, Devensian or Glaciofluvial Deposits, Devensian
Ross Sand Member (silt, sand) Largely concealed beneath younger deposits, identified at depth from borehole data, rare exposures represented as Glaciolacustrine Deposits, Devensian or Glaciolacustrine Deltaic Deposits, Devensian
Broomhouse Sand and Gravel Formation (sand and gravel) Largely concealed beneath younger deposits, where present, exposures usually represented as Glaciofluvial Deposits, Devensian, but also as Glaciofluvial Ice-Contact Deposits, Devensian
Broomhouse Sand and Gravel Formation (sand) Not recorded on the maps in the Clyde Gateway area (concealed beneath younger deposits), identified at depth from borehole data
Wilderness Till Formation Till - Devensian
Cadder Sand and Gravel Formation Generally concealed beneath younger deposits, identified at depth from borehole data, rare exposures represented as Glaciofluvial Deposits, Devensian
Example SSW-NNE cross-section of superficial deposits in the vicinity of the research site. Vertical exaggeration x 3. Ground surface derived from NEXTMap Britain elevation data from Intermap Technologies.

Bedrock geology

Geological maps and borehole data are available to view on the BGS GeoIndex Onshore. Data from mine abandonment plans includes extent, depth, working type, faults etc. for the stack of seven worked coal seams. The mine workings date from 1810–1934 with total extraction and stoop and room workings shown. It is expected that total extraction areas collapsed within a few years of mining to form a waste, and that the mines will be flooded.

Bedrock strata that will be accessed by the facility are the Scottish Upper, Middle and Lower Coal Measures formations of the Westphalian Scottish Coal Measures Group. These lithologically variable sedimentary rocks are well documented by borehole records and correlated using coal seams and marine bands.

Approximate depth relative to OD, metres, Location 01 Stratigraphy
-34 Glasgow Upper Coal (workings)
-66 Glasgow Ell Coal (workings)
-73 Glasgow Main Coal (workings)
-91 Humph Coal (workings)
-100 Glasgow Splint Coal (workings)
-104 Virgin Coal
-123 Airdrie Blackband Coal
-161 Airdrie Virtuewell
-167 Kiltongue Coal (workings)
-177 Base Coal Measures Group

Analysis of borehole, mine abandonment plan, map and legacy 2D seismic data to the north-east of the Clyde Gateway shows gently folded synclinal structures dissected by faults on a range of orientations. To the southeast of the study area the NW-SE trending Dechmont Fault is a major basin-bounding structure. E-W trending structures such as the Rutherglen, Shettleston and Great Dyke faults dissect the succession with smaller NNE to N trending structures.

Borehole prognosis for site 01 based on surrounding borehole records, mine abandonment plans and BGS 3D modelling
Depth grid to the Glasgow Main Coal (metres relative to Ordnance Datum) from the bedrock model described in Kearsey & Burkin (2018). Includes mapping data licensed from Ordnance Survey. © Crown Copyright and/or database right 2018. Licence number 100021290 EUL

Geological models

The BGS has updated 3-dimensional geological framework models of the superficial and bedrock geology, integrating a wide range of available data and knowledge. These models are currently progressing through a quality control system and will be released in due course. They will be continually updated as new data emerges during borehole drilling. Stochastic models of the superficial deposits also exist (Kearsey et al., 2015). The geological framework models form the basis for mine, hydrogeological and thermal models.

Further information is available from:

BGS 2007 1:10,000 bedrock map of NS66SW

BGS 2007 1:10,000 superficial deposits map of NS66SW

Kearsey, T, Williams, J, Finlayson, A, Williamson, P, Dobbs, M, Marchant, B, Kingdon, A & Campbell, S D. 2015. Testing the application and limitation of stochastic simulations to predict the lithology of glacial and fluvial deposits in Central Glasgow, UK. Engineering Geology, 187. 98 - 112. 10.1016/j.enggeo.2014.12.017

Kearsey, T. & Burkin, J. 2018. Model metadata report for the GGERFS initial bedrock model. BGS Open Report OR/18/053 – currently in review

Monaghan, A A, Arkley, S L B, Whitbread, K, and MCCormac, M. 2013. Clyde superficial deposits and bedrock models released to the ASK Network 2014: a guide for users Version 3. British Geological Survey Open Report, OR/14/013. 35pp. http://nora.nerc.ac.uk/id/eprint/505554/

Monaghan, A A, O Dochartaigh B, Fordyce, F, Loveless, S, Entwistle, D, Quinn, M, Smith, K, Ellen, R, Arkley, S, Kearsey, T, Campbell, S D G, Fellgett, M, Mosca, I. 2017. UKGEOS - Glasgow Geothermal Energy Research Field Site (GGERFS): Initial summary of the geological platform. British Geological Survey Open Report, OR/17/006. 205pp, http://nora.nerc.ac.uk/id/eprint/518636/

Contact

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