Terrestrial heat flow determination in Norway and an attempted interpretation.

Abstract

We present 21 new heat flow measurements from lakes in Norway, measured in 1974. The mean value of all the 46 lake measurements from Norway is 1.01 HFU, the mean of all drillhole measurements (19 values) is 1.03 HFU, and the mean of all the Norwegian data (65 values) is 1.02 (+-0.21) HFU. The data are presented as an isoline map, which shows two positive heat flow anomalies. One is in the Oslo Region, where it is situated over high heat generating rocks and the Oslo Graben. The second anomaly coincides with maximum crustral thickness and the Caledonian mountain belt in Norway and Sweden. An estimatation of the subsurface temperature indicates temperatures of 250o-350o at the Mohorovicic discontinuity under Norway. -Authors