Fig. 8From: The Cornubian geothermal province: heat production and flow in SW England: estimates from boreholes and airborne gamma-ray measurementsArea of Carnmenellis granite outcrop, radially extended by 2 km. a 1:50 k geological map showing metamorphic country rocks in black (slate and siltstone) and grey (hornfelsed slate and siltstone). GN granite, MCGN microgranite, MCGNA microgranite aplitic, MBAR metabasaltic rock (slate). The heavier black lines represent felsitic dykes. A small area of Paleogene gravels is arrowed. Water bodies are shown in blue. b The radiometric ternary colour image obtained using the three radioelement ground concentrations. Granite outline shown in black and water body outlines in white Back to article page