PALEOMAGNETISM OF NEOVOLCANICS OF THE EAST-SLOVAK LOWLANDS AND ZEMPLINSKE VRCHY MTS.: A STUDY OF THE TECTONICS APPLYING THE PALEOMAGNETIC DATA (WESTERN CARPATHIANS)

Year, pages: 1996, 13 - 20

Middle-Late Badenian to Late Sarmatian neovolcanics were investigated. They have been included in the areal type of the andesite, as well as dacite and rhyolite activity (Lexa et al. 1993). The thermal and AF tests of the samples revealed stable remanent magnetic polarization (RMP) in the andesites, rhyolites and rhyodacites. The carriers of magnetic properties in the rocks are oxidized Fe-Ti oxides. While the values of inclinations of stable RMP (both — normal and reversed) of the rocks are variable, the declinations of RMP are quite uniform. The declinations of RMP of volcanics (besides the Late Badenian /LB/ pyroxene andesites) are D = 323–328 (localities of normal polarity of RMP) and D = 139–145 (localities of reversed polarity of RMP), regardless of the petrographical type or time origin of rocks. All tectonic structures are bounded by faults of the NW-SE directions. We prefer the idea, that these declinations reflect the tectonic movements which were active in a post-magmatic period. The most probable explanation is that there was a counter-clockwise rotation (CCR 32° on average) of geological units in the past. However, no correction for post-volcanic tilting has been applied, so part of the variations may be attributed to this phenomenon. The first version of the explanation of the CCR of the neotectonic structures is, that this probably took place in the Pliocene-Quaternary period (as a result of a general subsidence of the area). The second idea has considered the fact, that the same age volcanic rocks in the Central Slovak volcanic area (Orlicky 1992), in the northern part of the Slanske vrchy Mountains (Nairn et al. 1967; Orlicky et al. 1974; Orlicky 1993), as well as in the Tokaji Mountains (Nairn et al. 1971) do not show rotation. This may be explained by the fact, that during the Badenian-Sarmatian time, the western part of the Carpathian Arc was no longer active while in the eastern part the final stage of arc-continent collision and related subduction continued.

Orlicky, O. 1996. PALEOMAGNETISM OF NEOVOLCANICS OF THE EAST-SLOVAK LOWLANDS AND ZEMPLINSKE VRCHY MTS.: A STUDY OF THE TECTONICS APPLYING THE PALEOMAGNETIC DATA (WESTERN CARPATHIANS). In Geologica Carpathica, vol. 47, no.1, pp. 13-20. 1335-0552.

Orlicky, O. (1996). PALEOMAGNETISM OF NEOVOLCANICS OF THE EAST-SLOVAK LOWLANDS AND ZEMPLINSKE VRCHY MTS.: A STUDY OF THE TECTONICS APPLYING THE PALEOMAGNETIC DATA (WESTERN CARPATHIANS). Geologica Carpathica, 47(1), 13-20. 1335-0552.