Sven Åke Larson

Geothermal investigations in the Bohus granite area in southwestern Sweden

Abstract Heat generation and heat flow were determined for the Bohus granite massif in western Sweden. This is the start of a major program concerning geothermal energy in Sweden. Neutron activation analyses, temperature measurements, thermal conductivity measurements have been carried out. As was expected the result, 76 mW m −2 , shows that even old Precambrian shields locally exhibit much higher values than normal.

Modelling of a Caledonian foreland basin in Sweden: petrophysical constraints.

Abstract Palaeotemperature studies of rocks on the Scandinavian Platform suggest heating of the near-surface Cambrian to Silurian sequence to temperatures between 80 and 120°C. A foreland basin has been proposed to have formed on the eastern side of the Scandinavian Caledonides, during the Silurian and Devonian, as a result of the Caledonian Orogeny. The aim of the paper is to model the thickness and horizontal extent of such a basin over Sweden. The thickness is estimated using two different approaches (i) by a thermal model based on measured thermal conductivities of preserved sediments, and (ii) by a flexural-subsidence model due to loading of an elastic lithosphere from the Caledonian mountain chain. The thermal model gave sediment thicknesses for southern-central Sweden in the range 2.4 km to 3.9 km, and the flexural model gave an estimate of approximately 2.4 km, but was strongly dependent on the assumed flexural rigidity. The width of the basin, also estimated by the latter modelling, was found to be approximately 300 km.

Investigation for Geothermal Energy in Sweden

Preliminary investigations of the geothermal energy potential in Sweden are being carried out in crystalline rocks of Precambrian age, as well as in the Triassic Buntsandstone. The geothermal potential of fracture zones is also being investigated. Different methods for prospecting have been tried and compared.

The bullaren lineament, southwestern Sweden—A possible site for geothermal heat extraction?

Abstract This paper embraces a study of a lineament in southwestern Sweden. The character of the lineament and its possibilities to be used as a geothermal extraction system have been evaluated. From this study it is evident that a low temperature area could be used for geotthermal heat extraction if suitable physical and economic conditions are obtained.