Large palaeomagnetic datasets
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.
Figures & Tables
Palaeomagnetism is a technique used to understand complex deformation patterns in fold-and-thrust belts; it can be used to characterize the distribution, magnitude and timing of vertical axis rotations, an elusive variable using other methods. A combination of palaeomagnetic and structural geology analyses has helped to unravel the geometry and kinematics of fold-and-thrust belts around the world and of different geological ages for more than 50 years. This volume comprises three sections: the first shows thorough overviews of western Mediterranean arcs and the western Carpathians; the second depicts several examples from the Andes, the Alps, Anatolia, Pyrenees, Iberian Ranges and the Atlas; and the third shows the latest research on the use of palaeomagnetism to understand fold-and-thrust belts in 3D and 4D in a more quantitative way and it also includes some methodological proposals to avoid common errors. In the papers of the first two sections, the combination of palaeomagnetic analyses with structural data, AMS or magnetostratigraphic analyses demonstrate the usefulness of palaeomagnetism in deciphering complex deformation patterns in fold-and-thrust belts.