New heat flow data for the United Kingdom, together with additional heat flow and heat production determinations for Caledonian-age granites, have led to a revision of the UK heat flow map and a re-examination of the relationship between heat flow ( q 0 ) and heat production ( A 0 ) for granites and basement rocks. Previously recognized broad belts of above-average heat flow are now resolved into separate zones which reflect, to a greater extent, the geological structure and tectonic history of the UK. The zones of highest heat flow are spatially associated with voluminous, high heat production granitoid batholiths in SW England, northern England and the Eastern Highlands of Scotland. A single linear correlation between q 0 and A 0 is no longer tenable and an analysis in terms of broad heat flow provinces, each with a characteristic upper-crustal heat production distribution and deep heat flow contribution, is also considered to be an oversimplification. On the q 0 –A 0 plot, the data form four separate clusters; three corresponding to the granite batholiths in SW England, northern England and the Eastern Highlands of Scotland, and the fourth to the basement rocks of central England and Wales. An explanation of the q 0 –A 0 data is proposed in terms of the crustal structure and thermo-tectonic setting of each area. In the case of the granite batholiths the data reflect the contrasting depth extent and radioelement-depth functions of the intrusions. These parameters in turn are related to the magmatic evolution and emplacement history of each batholith and the nature of the crust into which they were emplaced.

A revised and expanded lithostratigraphy is presented for the lower part of the Dalradian Supergroup in the Central Highlands. Stratigraphical correlations combined with lateral facies variations and geophysical studies are used to define a framework of NE-SW-trending marine basins that formed during a major phase of Neoproterozoic rifting. These basins extended rapidly and infilled with up to 5.5 km of turbiditic deposits, later thermal subsidence is indicated by the regional development of shallow marine shelf environments. The margins to these basins are characterized by lateral facies and thickness changes, stratigraphical omission and onlap relationships of both Grampian and Appin group strata onto a basement of predominantly gneissose strata. Whilst there is clear evidence for a stratigraphical and sedimentological break at the base of the Grampian Group there is presently insufficient structural or metamorphic evidence to prove an orogenic unconformity. Geochronological data confirm the presence of Precambrian events in the basement but have yet to do so in the cover.

No abstract

No abstract

Following the increase in oil prices in the mid‐1970s, Britain assessed its geothermal resources. Low‐temperature, hot‐water resources, in the range 40°C to 100°C, occur in Permo‐Triassic sandstones in several deep sedimentary basins. In total these resources are estimated at 69.1 × 10 18 joules (J) (2576 million tonnes coal equivalent). Resources also occur in Upper Palaeozoic aquifers but, as the permeability of these aquifers depends upon fissures, exploitation is difficult. The only surface manifestations of hot water at depth are the warm springs at Bath and Bristol and in the Peak District and Taff Valley, which issue from the Carboniferous Limestone. The potential of radiothermal granites for Hot Dry Rock (HDR) development has also been investigated, particularly in the Carnmenellis granite in Cornwall. Three boreholes drilled in the granite to depths of over 2 km have been connected by developing natural fractures. Water circulation between the boreholes and through the fractured rock has been successful.