Provenance and drainage evolution of the Northern Calabria forearc, southern Italy

Northern Calabria, situated at the southern end of the Italian Peninsula, is geologically complex due to its position at the convergence of the Eurasian and African plates. This complexity arises from significant deformation processes, including thrusting, folding, and extensive faulting associated with the closure of the Tethys Ocean and subsequent collisional and extensional tectonics. Thrusting during the Alpine orogeny resulted in a series of extensive nappe stacking, followed by structural reorganization and exhumation of these stacks during the Oligocene to Miocene, reflecting ongoing tectonic activity. Along the eastern margin of northern Calabria, fore-arc basins developed in response to the retreating subduction zone and evolution of the Calabrian arc. From north to south these are termed Rossano, Ciro, Crotone, and Catanzaro sub-basins. Analysing the stratigraphic record of these basins in terms of provenance shifts and changing drainage patters, will aid in further characterising the main exhumation phase of the northern Calabrian Massif, encompassing the Sila Massif and the Coastal Chain (Catena Costiera).A multi-proxy provenance study was designed combining heavy mineral analysis (via semi-automated Raman spectroscopy), garnet chemistry (via electron microprobe), and apatite trace element analysis and U-Pb geochronology (both via LA-ICP-MS). A collection of siliciclastic samples spanning ~15 Ma from Aquitanian to Messinian in age from the four pre-mentioned sub-basins were selected for measurement. The results present a wide range of both high grade to low grade metamorphics and granitoids, with strong contrasts present spatially and temporally. A high contribution of high-pressure metamorphic phases like lawsonite, glaucophane, and kyanite was identified in samples from the Rossano basin. Paired with the presence of garnets from greenschist/blueschist-facies rocks and apatite derived from mafic igneous rocks, sourcing is likely from Liguride units currently exposed in northern and western regions of northern Calabria (e.g. Catena Costiera, northern Crati valley). Occurrence of andalusite in the Serravallian/ Tortonian samples of the Ciro and Crotone basins points to sourcing directly from the Sila Massif plutonic rocks and/or its high-temperature metamorphic rims. Furthermore, large proportions of Ca-rich garnets in Crotone, and the oldest sample from Ciro, suggest metasomatic host-rocks also reflect this sourcing pattern. Apatite geochronology from Crotone shows one singular significant peak around 300 Ma, referring to the Variscan orogeny and further underlining a significant input from Sila granitoid rocks. The shift in sediment sourcing patterns from the lower to middle Miocene in the Rossano, Ciro, and Crotone basins indicate the exhumation of the Calabrian arc, along with its subsequent increasing and then decreasing relief, played a pivotal role in controlling the timing and direction of sediment transport.