This study aims at completing and refining results from previous paleomagnetic investigations carried our in various outcrops of the European Variscan belt. Sampling was performed in Visean effusive and intrusive rocks of the southern Vosges basin and the northern Massif Central, all emplaced in the time range 345-340 Ma. Stepwise thermal demagnetization of 254 specimens from 13 sites of the Doller Valley and nine sites of the Massif Central has yielded a very similar paleomagnetic record for both areas. With the exception of post-Carboniferous overprints isolated in the southern Vosges, two groups of directions, with both normal and reversed polarity have been evidenced. The first group of directions, labelled C, occurs in both areas and is characterized by scarce pre-tectonic magnetizations (two sites) and by syn-tectonic overprints (five sites) acquired during the Late Visean convergence, i.e. in the time-range 340-328 Ma. The mean pole C-o is 28 degreesS/45 degreesE (k = 139, alpha (95) = 5 degrees). The main group, labelled B, shows a negative fold test and a positive reversal test, indicating that the magnetizations are post-tectonic overprints, acquired after the main tightening phase, i.e. after 328 Ma. At a few sites in both areas were evidenced syn-tectonic B magnetizations that are in favour of an overprinting in the context of post-Visean extension tectonics. The mean posttectonic B direction of the Doller Valley (southern Vosges) 62 degrees/-25 degrees (k = 52, alpha (95) = 6 degrees, N = 11; VGP: 8 degreesN/127 degreesE) is consistent with the mean post-tectonic B direction 72 degrees/-23 degrees (k = 126, alpha (95) = 5 degrees, N = 6; VGP: 3 degreesN/114 degreesE) obtained from the tuffs, the grey microgranite and the dyke intrusive into the microgranite of the Massif Central. The occurrence of similar paleomagnetic records in the eastern and central Variscides implies that, from the Massif Central to the Sudetes, the belt has probably moved as one block, since Early Carboniferous. The change in inclination of the C components suggests a southward drift of the Moldanubian and Saxothuringien Variscides in the Late Visean (340-328 Ma). According to geological features, in the same time, the Rhenohercynian crust was underplating the Saxothuringian are and fore-are zone. Subsequent to 328 Ma, the drift turned into a rapid clockwise rotation by about 70 degrees around a pole located on southeastern corner of Baltica, leading to the closure of the Rhenohercynian oceanic basin. In the Namurian, large-scale overprinting (B components), likely related to post-rotation extension, affected the internal belt. The convergence continuing, the Variscides underwent a second clockwise rotation by about 45 degrees in the Late Namurian-Westphalian (320-305 Ma). Stacking of the Rhenohercynian sedimentary cover and thrusting over the London-Brabant basement may be related with this motion. (C) 2001 Elsevier Science B.V. All rights reserved.
