New insights on the fossil arc of the Tyrrhenian Back-Arc Basin (Mediterranean Sea)

Geology, geophysics and geodynamics of the Tyrrhenian Back-Arc Basin (BAB; central Mediterranean Sea) have been studied extensively during the last 50 years. However, some topics are still open: for example, the possible migration of the volcanic arc during the Ionian subduction of the past few Ma. We improved our knowledge of the geodynamics of the Tyrrhenian BAB in the area South of the Vavilov Volcano by analyzing multibeam bathymetry and unpublished single-channel reflection seismic and magnetic data. Furthermore, we studied the petrology of igneous rocks as well as facies and microfaunas of carbonates dredged from the Aurelia and Augusto seamounts. The Aurelia basement is made of basalts with calc-alkaline affinity. Carbonates from the Aurelia and Augusto seamounts consist of cemented Mg-calcite biomicrite crusts rich in planktonic foraminifera not older than Early Pleistocene. Based on our results, we interpret the Augusto and Aurelia seamounts as part of the active volcanic arc seaward of the Tyrrhenian BAB in Late Pliocene–Early Pleistocene.