Rudistid fringing reefs of Cretaceous shallow carbonate platform of Israel

Rudistid reefs are well developed in Albian-Turonian strata in Israel. These strata are divided laterally into shallow-shelf carbonate rocks (the Judea Limestone) deposited on the Arabian craton and fine-detrital carbonate deposits (the Talme Yafe Formation) on its margins. The main rudistid belts, developed during three depositional cycles, fringed the outer margins of the shelf platform. The morphologic features of the reef belts such as their biohermal shape, limited lateral extension, thick vertical continuity (135-350 m), and steep inclined fore-reef beds (25-35 degrees ) indicate the rudistid colonies developed into topographic wave-resistant structures on a steep sloping bottom facing the open sea. In contrast to recent coral reefs, the rudistid reefs are almost completely barren of encrusting organisms. Early submarine cementation is indicated in some void fillings. The stability of rudistid reefs was achieved mainly through the simultaneous growth of individual organisms in crowded interlocking and mutually cemented populations and was less the result of attachment to a firm substrate. Ecologic adaptation to environmental conditions such as depth, energy regime, salinity of the water body, and periodic subaerial exposure gave rise to lateral zonation of the rudistids in two different stratigraphic populations. Albian-Cenomanian Eoradiolites and Turonian Ichtiosarcolites formed the main reef belts fringing the shallow and hypersaline platforms, whereas Albian-Cenomanian Caprina and Caprinula and Turonian Radiolites and Vaccinites formed small patch reefs in deeper water of normal salinity.