Terrestrial heat flow versus crustal thickness and topography – European continental study

Abstract

The relation between heat flow, topography and Moho depth for recent maps of Europe is presented. Newest heat flow map of Europe is based on updated database of uncorrected heat flow values to which paleoclimatic correction is applied across the continental Europe (Majorowicz and Wybraniec 2010). Correction is depth dependent due to a diffusive thermal transfer of the surface temperature forcing, of which glacial–interglacial history has the largest impact. This explains some very low uncorrected heat flow values of 20–30 mW/m2in shallow boreholes in the shields, shallow basin areas of the cratons, and in other areas including orogenic belts where heat flow was likely underestimated due to small depth of the temperature logs. New integrated map of the European Moho depth (Grad et al 2009) is the first high resolution digital map for European plate, which is understood as an area from Ural Mountains in the east to mid-Atlantic ridge in the west, and Mediterranean Sea in the south to Spitsbergen and Barents Sea in Arctic, in the north. For correlation we used the following: onshore heat flow density data with palaeoclimatic correction (5318 locations), topography map (30x30 arc seconds, by Danielson and Gesch 2011) and Moho map by Grad et al (2009), providing longitude, latitude and Moho depth (with resolution of 0.1 degree). Analysis was limited to locations for which datasets were available. The area of continental Europe has been divided into two large domains: Precambrian East European craton and Palaeozoic Platform of the West Europe. In addition, two smaller areas were considered, corresponding to Scandinavian Caledonides and Anatolia. The results obtained reveal significantly different correlations between Moho depth, elevation and heat flow for these regions. For each region detailed analysis of these relations in different elevation ranges are presented. In general, it is observed that Moho depth is more significant for heat flow than elevation. Depending on the region and elevation range, heat flow value is up to two times larger than Moho depth, while relation of heat flow to elevation has much more variability.