Cool-water limestones of the Pannonian basinal system, Middle Miocene, Hungary

Reconciliation of fossil assemblages and sedimentological data with the pal eogeography of east-central Europe during the Middle Miocene has yielded a new interpretation about paleotemperature. The Pannonian basinal system of the Paratethys represents an unconventional and complex setting for cool wa ter carbonate-siliciclastic sedimentation and volcanism, The Middle Miocene Badenian Stage of Hungary is represented by four carbonate microfacies wit hin the Pannonian basinal system. Algal rudstones and floatstones, composed mostly of rhodolites, and bioclastic packstones, grainstones, and wackesto nes, accumulated in distinct basins within a regional framework of synrift tectonism, volcanism, and siliciclastic sedimentation. The diachronous natu re of these deposits reflect the repeated connection and disconnection of t he Paratethys. Minimum sediment accumulation rates varied widely within the local basins o f deposition (39-40 mm/1000 yr to < 1 mm/1000 Sr). A temperate type carbona te basinal system is suggested by variations in faunal diversity, Heterozoa n foramol biological associations dominated by red algal sediments, limited development of Porites patch reefs, a relatively high paleolatitude, and h igher global sea-level position for the Middle Miocene. Tectonism and the a ccompanying changes in paleogeography, oceanic circulation, and upwellings of colder water during drowning events may account for the paleoclimate rep resented by the cool-water carbonate sediments of the Paratethys during the Middle Miocene.