Upper Jurassic Carbonate Facies Succession at Breze (Velika Kapela, Croatia)

Abstract

Environmental differentiation at the end of the Lower Malm, as observed at Breze, was caused by gradual synsedimentary tectonics when the hitherto uniform Adriatic carbonate platform was partly differentiated into two different sedimentary environments. Thus the sunken intraplatform trough of unknown dimensions, which was possibly connected with the open basin (similar to the modern “Tongue of the ocean”?), formed the depositional site of deeper-water pelagic influenced platform carbonates. This gradual change in sedimentary environment can be defined as shallow-water platform facies retrogradation.

Periodic shedding of carbonate material, during the Upper Malm, from the perireefal/reefal margin of the intraplatform trough by mechanisms of gravity flows, caused the deeper-water inclined marginal part of the trough to be filled up resulting in the re-establishment of shallow-water sedimentary conditions. This process can be defined as shallow-water platform facies progradation whereby shallowing-upward sequence is formed.