The Franconian Basin thermal anomaly, SE Germany, revised: new thermal conductivity and uniformly corrected temperature data.

A homogenised data set of uniformly corrected temperature readings from 18 deep wells and new conductivity data of key strate in the basin is used to constrain the anomaly's geometry within an area of c.100 x 65 km2 and to calculate reliable conductive surface heat flow densities. High temperatures in the centre of the anomaly presumably originate in the basement but decrease rapidly away from the centre; geothermal potential is locally high, with surface heat flows exceeding 100 mW/m2 and reaching a maximum of 134 mW/m2 in the central area. The NW-SE elongated shape of the anomaly implies that the strike of the major regional fault system has a significant control on the present-day temperature field. A Peclet number analysis and the correlation of breaks in the temperature log with new thermal conductivity data prove a predominantly conductive heat transfer regime, although signatures of convective heat transfer have been proven for the aqyufers of the Buntsandstein, Muschelkalk and Keuper groups. Significant data gaps that strongly limit reliable three-dimensional representation of the field and understanding of its possible causes are the missing basement temperature data and the partial lack of data from greater depths.
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A homogenised data set of uniformly corrected temperature readings from 18 deep wells and new conductivity data of key strate in the basin is used to constrain the anomaly's geometry within an area of c.100 x 65 km2 and to calculate reliable conductive surface heat flow densities. High temperatures in the centre of the anomaly presumably originate in the basement but decrease rapidly away from the centre; geothermal potential is locally high, with surface heat flows exceeding 100 mW/m2 and reaching a maximum of 134 mW/m2 in the central area. The NW-SE elongated shape of the anomaly implies that the strike of the major regional fault system has a significant control on the present-day temperature field. A Peclet number analysis and the correlation of breaks in the temperature log with new thermal conductivity data prove a predominantly conductive heat transfer regime, although signatures of convective heat transfer have been proven for the aqyufers of the Buntsandstein, Muschelkalk and Keuper groups. Significant data gaps that strongly limit reliable three-dimensional representation of the field and understanding of its possible causes are the missing basement temperature data and the partial lack of data from greater depths.