Tectonostratigraphic model for the North Croatian and North Bosnian sector of the Miocene Pannonian Basin System

ABSTRACT The formation of the North Croatian Basin, which represents the south-western marginal part of the Pannonian Basin System and the Central Paratethys Bioprovince, began during Ottnangian time (early Miocene) by continental rifting. The syn-rift phase lasted until the middle Badenian (middle Miocene), and resulted in the formation of elongated half-grabens characterized by large sediment thicknesses strongly influenced by tectonics and gradually increasing volcanism. Towards the end of the syn-rift phase sinistral strike-slip faulting took place, transverse to oblique to the master faults, which disintegrated the longitudinal structures contemporaneously with volcanic activity. The depositional environments gradually changed from alluvial and lacustrine to marine. The syn- to post-rift boundary was characterized by significant erosion of the uplift fault block footwalls. The post-rift phase extended from the middle Badenian to the end of the Pontian (latest Miocene). Tectonic influence drastically decreased, volcanism ceased, and subsidence of the basin was controlled predominantly by cooling of the lithosphere. Marine connections gradually decreased, resulting in a transition from marine to brackish, 'caspi-brackish' and finally fluvial-marsh environments. By the end of the Miocene the basin was finally infilled. The basin evolution was also complicated by an alternation of phases of extension and compression.