CRUSTAL-SCALE COMPLEXITY OF THE CONTACT ZONE BETWEEN THE PALAEOZOIC PLATFORM AND THE EAST EUROPEAN CRATON IN THE NW POLAND

Abstract

Hypotheses on the trace and nature of the SW margin of the East European Craton (EEC) are reviewed. As new geophysical data was acquired, the location of the EEC margin was repeatedly revised. Magnetic anomalies associated with the SW part of the EEC and their relationship with the contact zone between the EEC and the Palaeozoic Platform are described. Based on an analysis of magnetic anomalies, seismic cross-sections, the LT-7, P1, P2 and P4 wide-angle reflection and refraction profiles, and the results of recent geothermal modeling, the geometry of the contact zone between the EEC and the Palaeozoic Platform in NW Poland has been redefined. Three important boundaries are distinguished, namely the Teisseyre-Tornquist Line marking the SW limit of the EEC at upper and middle crustal levels, the SW margin of the West Pomeranian Magnetic Anomaly that delimits the NE extension of the reversely magnetised lower crust of the Palaeozoic Platform, and the SW termination of the high velocity lower crust of the EEC. These boundaries and their characteristics reflect the tectonic complexity of the SW margin of the EEC in its Polish sector.