The earliest Cretaceous demise of the Slivnitsa carbonate platform: an interplay of three controlling factors

The flat-topped Slivnista carbonate platform was subaerially exposed during the earliest Valanginian and intense karstification occurred until the latest Valanginian producing various breccia types. The platform demise was caused by a relative sea-level fall but a drastic paleoenvironmental change around the Berriasian/Valanginian boundary also contributed to the shutdown of the carbonate factory. This is revealed by a rapid change from photozoan through heterozoan and then to non-skeletal mode of carbonate production. A similar biological crisis is known from other carbonate platforms across the Western Tethys and was probably associated with climate cooling, humidification and increase of marine trophic levels. The late development of the Slivnitsa platform was affected by synsedimentary extensional tectonics that led to differential uplift and emergence. This tectonic activity was most likely related to the Neo-Cimmerian (Late Cimmerian) phase.