Lithosphere in the Western Carpathians and its surrounding tectonic units - Geophysical study

Abstract

Geophysical methods are important tools for the investigation of the structure and geodynamic development of the lithosphere. The central and eastern parts of the Western Carpathians are bordered in the north by a thicker and stronger lithosphere of the European platform (100-150 km), which is underthrust (about of 50 km) beneath the margin of the overriding Carpathian orogen. This thickening is interpreted as remnants of subducted slabs. In contrast, the “thin” lithosphere at the western margin of the Western Carpathians can be considered as a result of oblique collision along a deep-seated transform zone between the platform and orogenic lithosphere. Neo-Alpine “soft” collision and retreating subduction of this orogen can also be discovered by means of quantitative interpretation of observed gravity field. The crustal thickness in the Western Carpathians ranges among 27-35 km. The central Western Carpathians are characterized by thicker crust (30-55 km) in comparison with thinner crust (25-30 km) in the Pannonian Basin System. This feature is probably the result of the youngest lithosphere processes from the Middle Miocene. Rheological properties of the Western Carpathian lithosphere show that the mechanical strengths decrease within the whole lithosphere from the area of the European platform via the Western Carpathians to the Pannonian Basin. The most remarkable and important first-order tectonic structures (seismo-tectonic zones) in the Western Carpathians are the zones of the Pieniny Klippen Belt, the Mur-Mürz-Leitha fault zone, the Čertovica fault zone and the Hurbanovo line. Map of neo-Alpine fault systems and neotectonic regions (blocks) of Slovakia was defined.