Shallow marine and continental conglomerates derived from coral reef complexes after desiccation of a deep marine basin: the Tortonian-Messinian deposits of the Fortuna Basin, SE Spain

Abstract

Some Miocene basins in SE Spain show an unusual arrangement of sedimentary facies associated with desiccated deep basins. Tortonian reefs and deltaic deposits are located around the basin margins but younger Messinian evaporites are exposed in central areas. These Messinian sediments contain thick conglomerates rich in coral debris. Although located hundreds of metres below the Tortonian reefs, they show subaerial features, including mud-cracks, vertebrate tracks, and rain-pits. In the coral reef derived conglomerates there are aragonitic coral fragments with aragonitic fibrous cement preserved by early cementation with calcium sulphate. The existence of these conglomerates within the Messinian evaporites helps to identify normal salinity and desiccation stages of the 'Messinian Salinity Crisis Event'.