CEPHALOPOD LIMESTONE BIOFACIES IN THE SILURIAN-OF-THE-PRAGUE BASIN, BOHEMIA

We interpret biostratinomy of Silurian cephalopod limestone biofacies of the Prague Basin, Bohemia. Two facies types are recognized. One is the result of a surface current and the other one is the effect of redeposition within the current itself in a shallower environment during storm events. Orientation, of cephalopod shells in these two facies types is discussed in relation to the Prague Basin development and to phenomena like telescoping, trap-structures and geopetal structures. Silurian cephalopod limestones of the northern Gondwana region show influence of equatorial surface currents which transported empty shells of cephalopods, larvae of bivalves and other fauna. These currents ventilated during lour-stand events the elevated parts of the bottom and deposited there the cephalopod limestone levels. All the occurrences are accompanied by bivalve-dominated Cardiola Community Group.