Abstract:
The Silica nappe (s.l.) of the Inner West Carpathians consists of an essentially non-metamorphic, platform-type sedimentary complex of Mesozoic (chiefly Triassic) age. Palaeomagnetic samples were collected from 16 sites throughout the southern and northern Gemeric parts of this unit and from one site of the Mesozoic Meliata series which underlies the Silica nappe (s.s.) in south Gemer. The samples from each site were treated using thermal demagnetization and well-grouped magnetic directions of individual components were found for 13 (14) sites. Detailed analysis of the directional data showed (a) post-folding magnetization for four late Triassic-Jurassic sites in the eastern Slovak Karst, (b) synfolding magnetization for five sites in the western Slovak Karst with a direction corresponding to local palaeomagnetic data of African affinity for the late Cretaceous and (c) primary magnetizations in the northern Gemeric area for only two rock units with a declination difference which implies a relative rotation between these units. As all secondary remanences are of normal polarity it is very likely that their acquisition is related to the emplacement of the Silica nappe during the early late Cretaceous. The dominant remagnetization mechanism probably is CRM but occasional contributions of TVRM are also conceivable