Overview of the geothermal field of Slovenia in the area between the Alps, the Dinarides and the Pannonian basin

Abstract

An updated review of the available geothermal data for Slovenia is presented. In order to evaluate the main tectono-thermal characteristics, an overview of three most relevant geophysical parameters, namely heat flow density, the distribution of shallow seismicity, and the depth of the Mohorovičić boundary, over a much larger, so-called Circum-Adriatic region, extending from the Tyrrhenian Sea to the Pannonian basin, is first given. The pattern and values of these parameters in the Adriatic Sea and just outside this area differ significantly from those of the outlying environment, and thus correspond roughly to the area known as the Adriatic microplate. Slovenia is situated at the northern rim of this geophysically diversified region. In the western part of the country, where the Dinarides and Southern Alps are situated, a good correlation has been found between the deeply lying Mohorovičić discontinuity, the low heat flow density, low temperatures at depth and a large negative Bouguer anomaly, whereas in the eastern part of Slovenia (the Pannonian basin) the rising mantle-crust boundary is associated with the high heat flow density, high temperatures at depth and a positive Bouguer anomaly. At the transition zone between the Southern Alps and the Dinarides, along the area of changing crustal thickness, a shallow seismicity belt is indicated. The only DSS profile in Slovenia, crossing the country in a SW-NE direction from Pula (Croatia) to Maribor, reflects the tectonic relations and seismicity between the Dinarides and the Pannonian basin.