Petrographic and geochronological records from turbidite successions of the Lucanian external chain: new insights for the tectono-sedimentary evolution of the Southern Apennines, Italy

In-depth petrographic characterization of the lithic fragments coupled with detrital zircon ages allowed to obtain relevant information about supply provenance (Critelli & Martín-Martín, 2024; Fornelli et al., 2022). Petrographic features and U-Pb spot ages on detrital zircons from turbidite sandstones of Tufiti di Tusa (TTF), Numidian Flysch (NF), Bifurto (BF), Gorgoglione (GF) and Serra Palazzo (SPF) formations, exposed in southern Italy, were detected to define provenance signatures aiming to better constrain the paleogeography and timing of the tectono-sedimentary main stages of the Apennines orogeny from Rupelian (TTF) to Burdigalian p.p. - Early Langhian (NF and BF) and Langhian-Serravallian -Early Tortonian (GF and SPF). Detrital zircon ages from the epiclastic record of the Tufiti di Tusa Formation indicate a sedimentary basin mainly fed by Rupelian synorogenic magmatic centers located in the central Mediterranean, and by minor input from Variscan granitoids and metamorphic rocks from the Mesomediterranean Microplate. Zircon data from Numidian and Bifurto quartz-arenites evidenced for the external Burdigalian-Early Langhian Apennines Foreland, an exclusive source area located on the Africa Craton; therefore, this sedimentary basin has not been fed by detritus from the Variscan or Alpine chain. Detritus from both Variscan crystalline basement forming the Alpine chain (Calabria-Peloritani Terranes) and Variscan magmatic and metamorphic rocks unaffected by Alpine tectonics (like Sardinia and Corsica proparte block) supplied the Middle Miocene depositional domain of Gorgoglione and Serra Palazzo formations. Based on these new petrographic, chemical, and geochronological data a revised paleogeographic history could be inferred for the Apennines foreland basins from Rupelian to Tortonian: i) in the early Oligocene abundant calc-alkaline products from a volcanic arc, probably located on the eastern domains of the Mesomediterranean Microplate, fed the internal domains of the Apennines foreland; ii) in the early Miocene the eastern domain of the Southern Apennines foreland was fed by quartz-rich sandstones coming exclusively from the African Craton; iii) important paleogeographic changes in the Middle – Miocene eastern foredeep were recorded: the Gorgoglione and Serra Palazzo sandstone composition and the detrital zircon ages indicate that their source areas were located on both internal (Mesomediterranean Microplate and Sardinia-Corso Block) and external geodynamic contexts (Fornelli et al., 2022). Critelli S. & Martín-Martín M. (2024) - History of western Tethys Ocean and the birth of the circum-mediterranean orogeny as reflected by source-to-sink relations. International Geology Review, 66(2), 505-515, https://doi.org/10.10 80/00206814.2023.2280787. Fornelli A. et al. (2022) - Detrital zircon ages of Oligocene to Miocene sandstone suites of the Southern Apennines foreland basin system, Italy. Journal of Palaeogeography, 11(2), 222-237, https://doi.org/10.1016/j.jop.2022.03.004.