ON LATE OLIGOCENE TO PLIOCENE DEPOCENTER MIGRATIONS AND THE EVOLUTIONOF THE CARPATHIAN-PANNONIAN SYSTEM

The Late Oligocene to Pliocene evolution of foredeep basins of the Eas tern Alps-Carpathians fold and thrust belt is marked by pronounced int ernal to external and lateral depocentre shifts. The latter shifts, co vering a present along-are distance of 1700 km, portray accelerating r ates of foredeep depocentre migration, particularly so in the late Ear ly and in the Middle Miocene, from about 7 to about 45 cm/yr. Lateral depocentre migration came to a close at the beginning of the Late Mioc ene; the subsequent Late Miocene to Pliocene foredeep infill history w as characterized by exponentially increasing accumulation rates in the intersection area of the East European (Ukrainian) and Moesian platfo rms. Successive steps in the evolution of the foredeep basins had pron ounced counterparts in the intra-Carpathian area. The beginning of acc eleration of foredeep depocentre migration in latest Early Miocene tim es was coeval with the inception of intra-Carpathian extensional tecto nics. The extremely rapid Middle Miocene depocentre shift, coupled wit h a change in direction of foredeep depocentre migration, corresponded with maximum extension in the intra-Carpathian area. The ensuing end of foredeep depocentre migration around the Middle-Late Miocene transi tion was coeval with the end of extension of the intra-Carpathian area , which, in turn, was followed by the inception of overall, thermal su bsidence at about 11.5 Ma. The timing of and spatial relationships bet ween discrete, coeval events in are and intra-arc evolution put unambi guous geological constraints on geodynamic modelling of the evolution of the Carpathian-Pannonian system. It is speculated that the geologic al observations may best be understood in terms of the surficial effec ts of lateral migration of slab detachment. Such effects would mirror the dominant role of a concentrating slab pull, taken to result in, e. g., a time-progressive acceleration of foredeep depocentre migration.