U-Pb detrital zircon ages and compositional features of Bifurto quartz-rich sandstones from Southern Apennine (Southern Italy): comparison with Numidian Flysch sandstones to infer source area

Annamaria Fornelli, Salvatore Gallicchio & Francesca Micheletti
Dipartimento Scienze della Terra e Geoambientali, University of Bari Aldo Moro, Italy. Corresponding author e-mail: annamaria.fornelli@uniba.it.


DOI: https://doi.org/10.3301/IJG.2019.02

Abstract

Two samples of quartz-rich sandstones belonging to Bifurto Formation in Southern Apennine, have been studied for their petrographical, geochemical and geochronological (U-Pb detrital zircon ages) features and compared with those of sandstones from five stratigraphic sections of Numidian Flysch in Southern Italy. The purpose of this comparison is to assess the homogeneity and provenance of detritus because quartz-rich sandstones of both formations are coeval having Burdigalian p.p. - Early Langhian age. The depositional domain of Bifurto Formation was located on the sinking carbonatic Campania-Lucania Platform whereas that of Numidian Flysch was within Lagonegro-Molise Basin at east of Campania-Lucania Platform. The Bifurto sandstones show sub-arkose - quartzarenitic composition with high Fe2O3 contents (Fe2O3 in the range 2.85 wt% - 4.83 wt%), however, the whole composition varies in the same compositional range of the Numidian Flysch sandstones. The U-Pb detrital zircon ages in Bifurto sandstones range from 2551±40 Ma to 425±9 Ma and the 93% of these age data is comprised in the same time lapse of detrital zircon ages of Numidian Flysch sandstones (3047±13 to 516±19Ma). These ages suggest a provenance area consisting by ancient orogens in which Pre-Cambrian and Silurian rocks are present. The absence of Paleozoic - Mesozoic ages excludes provenance from Variscan or Alpine rocks. On this basis, the African Craton represents the exclusive source area of Bifurto sandstones as well as of Numidian Flysch sandstones outcropping in Southern Apennine. Similar deductions have been proposed for Numidian sandstones outcropping along the Betic and Maghrebian chains from Spain to Morocco, Algeria and Sicily.

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