Sedimentary evolution of the Mesozoic continental redbeds using geochemical and mineralogical tools: the case of Upper Triassic to Lowermost Jurassic Monte di Gioiosa mudrocks (Sicily, southern Italy)

The continental redbeds from the InternalDomains of the central-western Mediterranean Chains havean important role in the palaeogeographic and palaeotectonicreconstructions of the Alpine circum-Mediterraneanorogen evolution since these redbeds mark the Triassic-Jurassic rift-valley stage of Tethyan rifting. The compositionand the sedimentary evolution of the Middle Triassicto Lowermost Jurassic continental redbeds of the SanMarco d’Alunzio Unit (Peloritani Mountains, SouthernItaly), based on mineralogical and chemical analyses,suggests that the studied mudrock sediments share commonfeatures with continental redbeds that constitute the InternalDomains of the Alpine Mediterranean Chains. Phyllosilicatesare the main components in the mudrocks. The10 A ° -minerals (illite and micas), the I–S mixed layers,and kaolinite are the most abundant phyllosilicates. Theamount of illitic layers in I–S mixed layers coupled withthe illite crystallinity values (IC) are typical of high degreeof diagenesis, corresponding to a lithostatic/tectonic loadingof about 4–5 km. The mineralogical assemblage coupledwith the A-CN-K plot suggest post-depositionalK-enrichments. Palaeoweathering proxies (PIA and CIW)record intense weathering at the source area. Further, thestudied sediments are affected by reworking and recyclingprocesses and, as consequence, it is likely these proxiesmonitor cumulative effect of weathering. The climate inthe early Jurassic favoured recycling and weatheringoccurred under hot, episodically humid climate with aprolonged dry season. The source-area is the low-gradePaleozoic metasedimentary basement. Mafic supply isminor but not negligible as suggested by provenanceproxies.