Provenance and tectonic implications of heavy minerals in Pliocene-Pleistocene siliciclastic sediments of the southern Apennines, Italy

Abstract

During the late Tortonian-Pleistocene, rifting in the Tyrrhenian region and compression in the Apennines coexisted, with an eastward migration of the rift basin-thrust belt-foredeep systems. In a northwest-southeast area of the southern Apennine Pliocene deposits, accumulated in piggy-back basins, and Pliocene-Pleistocene sediments deposited in the foredeep basins, are contiguous. Here our attention is focused on the heavy minerals, which are sensitive indicators of source rocks. Garnet, blue amphibole, staurolite, clinopyroxene, epidote have been analysed and compared with the minerals of the likely protoliths. Blue amphibole and staurolite derive from Early Miocene ‘Tufiti di Tusa e Arenarie di Corleto’ Formation; pyroxenes derive from Pleistocene Vulture volcanics and, possibly from Pliocene volcaniclastic strata cropping out in Basilicata. Interestingly, blue amphibole and staurolite, present in the Early Miocene volcanolithic and quartzofeldspathic sandstones of the ‘Tufiti di Tusa e Arenarie di Corleto’ Formation, are absent in Tortonian siliciclastic strata, but appear again in Pliocene-Pleistocene siliciclastic sediments. The space-time distribution of these minerals was controlled by important morphostructural modifications affecting the southern Apennine thrust belt.