Terrestrial heat flow density in Poland - a new approach

Abstract

The Earth's thermal field, particularly the heat flow density (HFD), is a valuable source of information on geodynamic processes within the Earth's crust, conditions for hydrocarbon generation and on areas and formations promising for geothermal energy. Lithospheric thermal and rheological modelling is critically dependent on high-quality surface heat flow values. The available maps of heat flow density, not only for the area of Poland, are not reliable from the point of view of the current state of knowledge. The main critical factor in determining heat flow density is the knowledge of depth distribution of thermal conductivity. We used a new method of estimating the thermal conductivity from well logging data interpretation with control calibration based on laboratory determined thermal parameters. We consider that the observed vertical variations of HFD in the shallow part of profiles (< 2000 m) are mainly due to a Holocene warming. We have proposed a new original method of determination of HFD based on modelling of palaeoclimatic effect. Using this method, we have calculated new HFD values for 308 deep boreholes and completed a new map of this parameter for Poland, which is the first of this type. We propose to undertake a critical analysis of all the existing heat flow data not only for Europe that may change the present understanding of global heat flow.