Depths to the bottom of magnetic sources and geothermal prospectivity in Southern Germany
G. Gabriel, I. Dressel and D. Vogel
Journal name: First Break
Issue: Vol 30, No 4, April 2012 pp. 39 - 47
Info: Article, PDF ( 802.14Kb )
Price: € 30
The exploration effort for geothermal energy, for both district heating and electricity generation, is increasing rapidly in Germany. We have analysed recently compiled magnetic anomaly data to estimate depths to the bottom of magnetic sources (DBMS) as proxy information about the thermal conditions within the crust. The investigated area comprises the Bavarian Molasse Basin and parts of the Upper Rhine Graben. These two geological provinces are particularly important for geothermal exploration in Germany, because of their favourable transmissibilities and high geothermal gradients, respectively. We used geothermal constraints from a shallow borehole to optimize the window operator size and the wavenumber range in DBMS estimation. A window size of 200 km × 200 km is a good choice for this type of analysis, and an overlap between adjacent blocks of 180 km results in a smooth depth map and enables the identification of outliers. In southern Germany, the DBMS varies from 21 km north of Stuttgart to 36 km in the region south of Regensburg, with a mean depth of 26 km. Variations in the DBMS compare reasonably well with surface heat flow and very well with the temperature field at 3 km depth.