THE LATEST STAGE OF DEVELOPMENT OF THE LITHOSPHERE AND ITS INTERACTION WITH THE ASTHENOSPHERE (WESTERN CARPATHIANS)

The latest stage of the development of the Western Carpathian are and the Pannonian Basin was characterized by a lithospheric disintegration which occurred as a consequence of the transition from a transpressio nal to an extensional regime. This process was accompanied by both cru stal thinning and, what is more important by thinning of the lithosphe re. The thinning of the lithosphere was associated with an uplift of a sthenospheric, partially molten masses, accompanied by local asthenoli ths. This paper discusses the geological features and the development of processes involved in the ascension of partially molted masses into subcrustal levels through the older discontinuities. Geophysical and petrological evidence have shown that the uplift of these local partia lly molten masses nearly reached the Moho discontinuity. The mantle xe noliths transported to the surface by the youngest alkaline basalts an d the study of their phase transition give petrological evidences for this process. Further geophysical indications of this process are seis mic and magnetotelluric sounding (MTS) anomalies and geothermal condit ions. The interpretation of other seismic profiles with prolonged regi stration, density and partly geomagnetic modelling have also been used in the interpretation. These data are discussed in the light of prese nt knowledge of the tectonic development of Western Carpathians and th e Pannonian Basin.