Petroleum Geology Student Contest - 3rd edition

This work is an analysis of the coral sequences in eastern Sicily to understand the paleoenvironment. This study contains the sedimentological and compositional informations on the development of coral colonies in the Mediterranean Sea that are also important for oil exploration. The sedimentological study and analysis of facies of the stratigraphic sections located in the Syracuse area made it possible to understand the depositional environments of the analyzed sequences of the lower-middle Miocene (Punta Bonico section) and of the lower Upper-Messinian Tortonian (Faro Santa Croce, Ognina and Plemmirio sections). These facies were afterwards compared with models proposed for the Sicilian and Mediterranean area. The study of the sections has allowed us to characterize that from the compositional and textural point of view. The succession of Punta Bonico resulted composed by the lithofacies FR, in which Miogypsina and Amphistegina would suggest mesooligophotic environments (mid ramp). The red algae in the FC lithofacies, associated with the order of Miliolids, indicate euphotic environments (inner ramp). Even though the Miogypsina and the rare planktonic discovered in the area would indicate deeper areas. Finally, the composition and texture of GB lithofacies indicates a rather high hydrodynamic energy which is typical of inner ramp - euphotic zone. Comparing these lithofacies with some carbonate systems from the same age the results are both a spread of corals in deeper habitat, the meso-oligophotic zone. The successions of Faro Santa Croce, Ognina and Plemmirio are characterized by the lithofacies BC, that is indicative of a variable depositional depth (mid-inner ramp). In some areas, the presence of Nummulitids, Operculina, planctonics and non-articulated red algae in the matrix hint a mesooligophotic zone. The components of the PWM lithofacies suggest the presence of shallow clear waters with low hydrodynamic energy (probably a lagoon). The sedimentary structures and components of the lithofacies PO point to the presence of underwater dunes (inner-middle ramp). The peloids, ostracods and fine texture in the PWP lithofacies indicate low-energy environments (inner ramp-lagoon). Finally, the PB lithofacies contains numerous green algae and Pecten, which are typical in low sea environments (euphotic zone). The novelty of this study consists in the discovery of corals that can be associated with the meso-oligophotic zones, while all previous studies only uncovered corals in more superficial and euphotic areas. While this study is far from exhaustive, it contains elements that shed new light on the Mediterranean coral successions and may spark interest in some outcrops that have not yet been studied.