Palaeomagnetic results from the fold and thrust belt of the Western Carpathians: an overview

Abstract

The Western Carpathians are separated into an Outer and Inner Carpathians (both comprising several nappe systems) by the extremely narrow and highly deformed Pieniny Klippen Belt. The main phase of deformation and thrusting took place during the Late Cretaceous in the Inner Carpathians, at the end of Cretaceous–Paleocene in the Pieniny Klippen Belt and in the Miocene in the Outer Carpathians. In this paper a large amount of palaeomagnetic results of different quality available from several nappe stacks and from overstep sequences were reviewed and interpreted in terms of tectonics. The data suggest that all three main units participated in two phases of anticlockwise rotation starting at 18.5 Ma, that is, the Outer Carpathian nappes in front of the already consolidated Alpine–Carpathian–Pannonian block became accreted to the block. Late Cretaceous nappe transport, Neogene uplift of ‘core mountains’ and possibly oroclinal bending of pre-Oligocene age can account for important differences in pre-Cenozoic palaeomagnetic declinations. Most of them exhibit less or no anticlockwise rotation suggested by the overstep sequences, implying pre-Cenozoic clockwise rotations of variable angles.

Stepwise clockwise rotation of the Cenozoic stress field in the Western Carpathians as revealed by kinematic analysis of minor faults in the Manín Unit (western Slovakia)

“…How ever, any re con struc tion of palaeostress states is com pli cated by the Mio cene block ro ta tion of the whole Western Carpathians (e.g., Fodor, 1995;Marko et al, 1995;Márton et al, 2016). Con se quently, changes of palaeostress ori en tation in the area were likely caused by a com bi na tion of the clock wise ro ta tion of the stress field and the coun ter clock wise (CCW) ro ta tion of the ALCAPA microplate.…”

“…De for ma tion structures of this stage are not ob served in the Bartonian-Oligo cene de pos its of the Cen tral Carpathian Paleogene Ba sin, there fore the first palaeostress state re corded must have oc curred earlier, most prob a bly dur ing the late Mid dle Eocene. There fore, con sid er ing a Mio cene block ro ta tion of the West ern Carpathian of c. 50-60° (Márton et al, 2016), the orig i nal ori en ta tion of the main com pres sive palaeostress axis should have been in the NNW-SSE di rec tion (Fig. 10).…”

“…Dur ing the Ottnangian-Early Badenian, the en tire West ern Carpathian do main ro tated as a unity about 50-60° anti-clockwise (e.g., Kováè and Túnyi, 1995;Márton et al, 2016). At the same time, older de for ma tion struc tures should also have rotated.…”

An integrated paleomagnetic and magnetic anisotropy study of the Oligocene flysch from the Dukla nappe, Outer Western Carpathians, Poland

“…Márton et al (2009) studied the paleomagnetism and the magnetic aniso tropy of the Paleogene (subordinately Lower Miocene) grey clay, silt and mudstones from the Magura and the Silesian Nappes. Their results pointed to a general 50° CCW rotation of the Magura nappe and of the central and eastern segment of the Silesian nappe, and somewhat larger for the western part of the Silesian Nappe), which must have taken place after the Oligocene (Márton et al 2016). The AMS (anisotropy of magnetic susceptibility) measurements revealed that the magnetic foliation was due to compaction and the magnetic lineation to weak compressional deformation.…”

Introduction: Palaeomagnetism in fold and thrust belts: new perspectives

“…1); the Western Carpathians (Márton et al 2015) and the Western and Central Mediterranean arcs . In both cases, synthetic and robust palaeomagnetically deduced VARs are used to constrain the kinematic and geodynamic evolution in these regions.…”