Lithofacies modelling and sequence stratigraphy in microtidal cool-water carbonates: a case study from the Pleistocene of Sicily, Italy



ABSTRACT Quaternary carbonates in SE Sicily were deposited in seamount and short ramp settings during glacio-eustatically driven highstand conditions. They provide an excellent opportunity to investigate the depositional and erosional aspects of cool-water carbonate sedimentation in a microtidal marine water body. The derived ramp facies model differs significantly from modern-day, open-ocean ramp scenarios in projected facies depth ranges and in the preservation of inshore facies. A sequence stratigraphic study of the carbonates has confirmed many established aspects of carbonate sedimentation (e.g. production usually only occurred during highstands). It has also revealed several new features peculiar to water bodies with little tidal influence, including ‘catch-up’ surfaces taking the place of transgressive facies, second-order sequence boundary events being most important as triggers for initiating resedimentation and a virtual absence of sediment shedding to the basin during the terminal lowstand. Production in the carbonate factory lasted for about 0·5 Myr. Despite this, carbonate production was considerable and included both bioconstructional and bioclastic-dominated facies and the production of abundant lime muds. A model for eustatically controlled cool-water carbonate production and resedimentation in microtidal marine water bodies is presented. This is considered to be more applicable to Neogene and Quaternary strata in the Mediterranean region than are current open-ocean models.