Heat Flow and Analysis of the Thermal Structure of the Lithosphere in the European Part of the USSR

Abstract

The thermal field of the region reflects its long and complicated geologic evolution since the Archean to the present time. The heat flow density varies from 20–30 to 100–120 mW m−2. There are several heat flow levels defined by radiogenic heat generation in near-surface rocks and the time of the active reconstruction of the earth’s crust.Within the Precambrian East-European platform, particularly in the Baltic and Ukrainian shields, the lateral heat flow density changes are mainly due to associated changes of radiogenic heat production in the earth’s crust. In many blocks a linear relationship between the heat flow density and heat production is observed. However, there are zones that have been so reconstituted by frequent tectonomag-matic processes that it is practically impossible to establish a linear relation between the heat flow density and mean heat production in many near-surface units.In active areas the heat flow level is defined by various physical and chemical processes accompanied by heat release, absorption or heat transport from the interior due to a sharp change of the heat transfer mechanism in the lithosphere. These processes create pronounced transient heat flow anomalies.Methods of heat flow analysis and construction of geothermal lithosphere models are elaborated. The results enable us not only to study radiogenic heat production and heat conductivity of a medium but also complex processes such as asthenosphere uplift, intrusion, accumulation of sediments, denudation and other phenomena.Strong transient anomalies of heat flow are analyzed, and methods for interpreting thermal fields under conditions of complex structure and topography, sedimentation and diapirism are considered. The procedures permit the construction of the temperature distribution in the lithosphere beneath major tectonic features of East Europe.KeywordsHeat FlowHeat GenerationThermal StructureHigh Heat FlowUkrainian ShieldThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.