Geothermal data from the Vienna Basin

Abstract

More than thirty new rock temperatures in the Vienna basin show gradients of about 25° to 35°/km. The central crystalline zone of the Alps and Carpathians divide the Vienna basin and the Little Hungarian basin. Temperature gradients in the Little Hungarian basin are 45°–50°/km. The average estimated heat flow in the Vienna basin is about 1.2 μcal/cm2 sec, whereas in the Little Hungarian basin an average value of 2.0 μcal/cm2 sec was observed. Toward the central part of the Carpathian basin the measured heat flow increases to 2.6 μcal/cm2 sec. The bottom rock of the Vienna basin is northern Alpine limestone and flysch. The bottom of the Little Hungarian basin is central Alpine type crystalline rock. Since the heat flow in flysch rocks of the Carpatho-Ukraine was measured at 0.75–1.35 μcal/cm2 sec, it can be concluded that the long continuous flysch belt from Switzerland to the Carpatho-Ukraine is characterized by normal or low heat flow. The Alpo-Carpathian central zone divides territories with continental normal heat flow from territories with high heat flows. High heat flow can be observed in the central zone of the Alps and within the Carpathian arc. Normal and low heat flow exists in the flysch zone of the Alps and Carpathians.