Coral fauna and facies of the oligocene fringing reef near Cairo Montenotte (Liguria, Northem Italy)

Abstract

1 km south of Cairo Montenotte, a small fringing reef in limestone facies was foumed in terrigenous sediments during the Oligocene transgression. It has a thickness of 40–60 m. The lower part consists of terrigenous-influenced to pure limestone and contains isolated corals, or concentrations of massive corals in coral mounds. The upper part is principally characterized by a dense framework of massive, sometimes branching corals. The coral fauna consists of 27 species, dominated byGonioporamosa orActinacis rollei. 23 species were found on the reef front, none of which predominate. The reef tapers off in various directions in small units of reef limestone and biocalcarenite. The coral fauna and the reef faccies are studied in detail. The vertical development of the coral limestones and lateral variations in the reef core, as well as the distal facies, are described. The corals are identified and the general character of corals and reef framework investigated. Communities and palaeoeecological relations are described.