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RESEARCH PRODUCT

Palaeomagnetic investigations in the Hercynian mountain belt of central Europe

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Abstract The palaeomagnetism of sediments and volcanics of Middle Devonian to Early Carboniferous age has been studied in the Hercynian realm of the Vosges, Harz and Franconian Forest (France and Germany). After appropriate cleaning, characteristic directions of natural remanent magnetization (NRM) have been determined, which are considered to be of pretectonic origin according to rock magnetic and structural geological evidence. A mean palaeopole for the Devonian rocks in the areas investigated was determined at — 29.7°N and 9.0°E. The site latitude derived from the Devonian rocks agrees very well with that observed in Great Britain and Britanny. The significant difference in longitude between our Devonian poles and the other European data may be due to an anticlockwise rotation of central Europe with respect to the northern Hercynian Foreland. The Carboniferous rocks yield a mean palaeopole at —41.7°N and 340.4°E, matching the Carboniferous part of the European polar wander path. A fold test within Carboniferous greywackes from the Harz mountains proves a pre-folding origin of the NRM of these rocks. However, this stable magnetization direction indicates local or regional tectonic displacement. Our results do not support any major latitudinal motions of continental segments in central Europe during the Hercynian orogeny. The Palaeozoic palaeomagnetic data from the Vosges, Franconian Forest, Harz, Britanny and Central Massif can be used to interpret the Hercynides in terms of a large scale shear belt.