Thermal and Rheological Model of the European Lithosphere

Abstract

A thermal and rheological model of the European lithosphere (10 degrees W-35E; 35N-60N) is constructed based on a combination of new geophysical models. To determine temperature distribution a tomography model is used, which was improved by corrections for the crustal effect using a new digital model of the European crust (EuCRUST-07). The uppermost mantle under western Europe is generally characterized by temperatures ranging between 900 and 1,100 degrees C, with the hottest areas corresponding to basins, that experienced recent extension (e.g., Tyrrhenian Sea and Pannonian Basin). By contrast, upper mantle temperatures at this depth under eastern Europe are about 550-750 degrees C, whereby the lowest values are found in the northeastern part of the study area. EuCRUST-07 and the new thermal model are used to calculate the strength distribution within the European lithosphere. Differently from previous approaches, lateral variations of lithology and density derived from EuCRUST-07 are used to construct the new strength distribution model. Following the approach of Burov and Diament (1995), the lithospheric rheology is employed to calculate variations of the elastic thickness of the lithosphere. According to these estimates, in western Europe the lithosphere is more heterogeneous than in eastern Europe. Western Europe, with dominantly crust-mantle decoupling is mostly characterized by lower values of strength and elastic thickness. The crustal strength provides a large contribution to the integrated strength (similar to 50% of the integrated strength for the whole lithosphere) in most part of the study area (similar to 60%). The new results are important in view of recent disputes on the strength distribution between crust and mantle lithosphere.