Seismic images of the collision of Central European Terranes

Abstract

Geologically, Europe consists of a combination of Phanerozoic and Precambrian terranes. Our research focuses on understanding the collision and suture zones between these terranes by imaging the lithosphere–asthenosphere boundary (LAB) and the mid-lithospheric discontinuity (MLD) using seismic S-to-P converted waves. The amount of available data from permanent broad-band stations and temporary deployments has significantly increased in recent years. This development allows us to resolve new details regarding continental collisions in Europe. We interpret the new data to show that the Scandinavian MLD extends southward beneath the Caledonides and Variscides, reaching as far as the Bohemian Massif. We have also identified a west-dipping seismic phase extending from the East European Platform (EEP) to the centre of the Pannonian Basin. This phase could represent the MLD of the EEP, akin to the collision between Scandinavia and Phanerozoic Europe in the north. To support these novel findings, geodynamic modelling is required to explain the processes leading to such a structure, which is beyond the scope of this paper. Below the Alps, we confirm earlier observations of the European plate subducting below the Adriatic lithosphere.