Table 4.

Subsurface temperatures

LocalityPopulationT (°C)Ref.NoteLocalityPopulationT (°C)Ref.Note
Northern and North-central EnglandWessex Basin and surroundings
Darlington105 60054BSouthampton254 30048B
Harrogate156 30052BEastleigh129 60048B
Leeds781 70050BWinchester122 00048B
Wakefield336 80050BChichester118 20048B
Bury188 70050BTunbridge Wells117 10048B
Rochdale216 20049BEastbourne103 10048B
Newcastle upon Tyne296 50048YBournemouth197 70046B
Barnsley241 20048BMaidstone166 40046B
Oldham232 70048BPoole151 50046B
Gateshead201 60048YTonbridge127 30046B
Stockton-on-Tees195 70048BSevenoaks119 10046B
Sheffield575 40046BFareham115 40046B
Manchester541 30046BCrawley111 40046B
Bradford534 30046BBasingstoke174 60044B
Huddersfield437 00046B1Havant123 60044B
Hull260 20046BWorthing108 60044B
Ashton-under-Lyne223 20046B2Croydon382 30042B5
Middlesbrough140 40046BBromley326 90042B5
Lichfield103 10046BBrighton289 20042B6
Stockport290 60045BGreenwich279 80042B5
Chesterfield104 40044BMedway278 50042B
Nottingham325 30042BPlymouth264 20042B
Bolton283 10042BBexley244 80042B5
Walsall278 70042BPortsmouth214 80042B
Rotherham261 90042BSutton202 20042B5
Derby256 20042BThurrock167 00042B
Salford248 70042BHorsham138 00042B
Trafford234 70042B3Torbay133 90042B
York208 40042BGravesend106 80042B7
Grimsby159 10042B4Dartford105 50042B5
Mansfield107 40042BLewes101 40042B

Values of the temperature T, measured or estimated at 1 km depth, from Busby et al. (2011) (B) or Younger et al. (2016) (Y), are plotted for towns and cities in Britain with populations >100 000 (population data from ONS 2017). The values reported were measured by Younger et al. (2016) beneath Newcastle upon Tyne and are assumed beneath neighbouring Gateshead. These relatively high temperatures, listed, arise due to combinations of relatively high heat flow and/or relatively low thermal conductivity sediments, including thick sequences of Carboniferous mudstone in sedimentary basins in northern and central England. Sites are grouped geographically; no localities in Scotland or Wales have high enough subsurface temperatures for inclusion, whereas Northern Ireland has not been assessed. Annual mean surface temperatures are within c. ±1°C of 10°C at almost all localities listed, so geothermal gradients in the uppermost 1 km beneath the Earth's surface can be readily calculated approximately. Notes: 1, Kirklees Metropolitan Borough (MB); 2, Tameside MB; 3, Trafford MB; 4, North East Lincolnshire Unitary local Authority (UA); 5, London Borough; 6, Brighton & Hove UA; 7, Gravesham District.