Major crustal features between the Harz Mountains and the Baltic Shield derived from receiver functions

Abstract

A large passive teleseismic experiment (TOR) was carried out from northern Germany across Denmark to southern Sweden to study the structure of the lithosphere and asthenosphere across the Trans-European Suture Zone. A number of stations have also been deployed along the DEKORP-BASIN '96 profile in northeast Germany permitting a direct comparison of active and passive seismic methods. Analysis of receiver functions (P-to-S converted waves) leads to some new geological results. The margin of Baltica is found to penetrate the entire crust. Its boundary dips to the southwest reaching the upper crust below the Caledonian Deformation Front (CDF). A 200-km-wide zone south of the CDF and reaching the Elbe line has a heterogeneous crustal structure including a Moho depression and ‘crocodile’ structures in the Receiver Functions at the Moho. This zone is interpreted as the transition zone between Proterozoic and Phanerozoic Europe, which was strongly affected by Permian magmatism and which may contain in its northeastern part high-velocity blocks of the Baltic crust detached and displaced during the Caledonian Orogeny. The major PS converting boundaries are the crystalline basement and Moho, which agree well with the wide angle and vertical incidence seismic observations.