Terrestrial heat flow in the Carpathians

Abstract

The Hungarian basin is an interesting feature of the Alpine geosyncline system. This Tertiary basin is surrounded by the Carpathians and Dinarics and has an elliptical shape. The bottom rock of the basin is fractured, not folded. The heat flow in the Hungarian basin varies between 1.5 and 3.3 μcal/cm2 sec according to seven measurements of heat flow and about 400 temperature gradients observed in wells of 400- to 2000-m depth. The temperature gradient is between 40 and 80 deg/km. The average flow of heat is about 2.4 μcal/cm2 sec. No heat flow measurements were undertaken outside the Carpathians and Dinarics, but observation of temperature gradients showing values between 20 and 30 deg/km allow us to conclude that a heat flow of about 1.0 to 1.2 μcal/cm2 sec exists outside the Hungarian basin. The Hungarian basin seems to be an isolated geothermal high surrounded by territories with normal heat flow values. Similar geothermal structures may be found in the western Mediterranean, in the Caucasus, and around the Japan Sea.