Provenance of shales and sedimentary history of the Monte Soro Unit, Sicily

Source area weathering, provenance and tectonic setting from the Lower Cretaceous Monte Soro Unit shales (North-eastern Sicily) have been analysed for mineralogical and chemical compositions. Samples are characterized by high values of MMI index. Among clay minerals I/S mixed-layered and illite are prevailing on chlorite and kaolinite. The amount of illite layers among mixed-layered smectite/illite reflects late diagenetic post depositional conditions reasonably reached during the post-Cretaceous subduction and related collision involving the European and African plate margins. Major and trace elements abuncances indicate the dominant detrital nature of the shales with minimal or absent hydrothermal and biogenic contributions. TiO2/Al2O3 ratios are distinctive of shales produced by weathering of felsic to intermediate continental crustal rocks. High CIA and CIW values suggest that the source area was subjected to a prolonged and/or intense chemical weathering. The chemical composition and trace element ratios Zr/Y, Zr/Nb, Zr/Ti, Nb/Y, Th/Cr, Th/Co, La/ Co, K/Rb are close to those of the metamorphic basement of the Monti Peloritani segment of the European block. However, in our case, it is difficult to distinguish between a first-cycle sediment production and a recycling of the Upper Triassic – Lower Jurassic Verrucano continental sediments, being the metamorphic basement mainly formed by metagraywakes and metapelites.