Stratigraphy, composition and provenance of argillaceous marls from the Calcare di Base Formation, Rossano Basin (northeastern Calabria)

Abstract

AbstractThe Calcare di Base Formation is a part of the Rossano Basin characterizing the Foreland Basin System of northeastern Calabria. Messinian argillaceous marls from the Calcare di Base Formation have been studied to characterize the sedimentary evolution of this formation during the post-orogenic phases of the Calabria–Peloritani Arc. The mineralogical assemblage of the argillaceous marls is dominated by phyllosilicates (illite, chlorite, illite/smectite mixed layers and traces of kaolinite), carbonate minerals (calcite, aragonite and dolomite), quartz and traces of feldspars (both K-feldspars and plagioclase), gypsum and celestine. The palaeoweathering index records changes at the source, reflecting variations in the tectonic regime as shown in the A–CN–K plot, where the studied samples describe a trend typical of a source area in which active tectonism allows erosion of all zones within weathering profiles developed on source rocks. The studied samples are derived from an environment in which non-steady-state weathering conditions prevailed. This trend could record deformational events that affected the Mediterranean area during the Miocene. The Th/Sc versus Zr/Sc ratios and Al–Zr–Ti plot suggest that the samples likely record a recycling effect from their basement rocks. The geochemical proxies of these samples suggest a provenance from a mainly felsic source. The Messinian argillaceous marls record that deposition probably occurred in a semi-closed marine environment mainly subject to hypersalinity with local episodes of meteoric water influx, during a period characterized by persistent dry and warm/arid conditions alternating with relatively wet conditions.