Tyrrhenian Sea

The Tyrrhenian Sea is the easternmost basin of the western Mediterranean boudinated backarc lithosphere (where the Provençal, Valencia, and Algerian troughs also developed) in the hanging wall of the Late Oligocene to Present Apennines-Maghrebides subduction. The Apennines slab retreated "eastward", which kinematically requires an eastward mantle flow either to compensate or push the slab rollback. All the western Mediterranean backarc basins, and in particular the Tyrrhenian sea, are asymmetric, being more extended and magmatically intruded in the eastern side, as testified also by the higher heat flow. The extension in the Tyrrhenian sea evolved to oceanization in two main areas from west to east, i.e., the Vavilov (7-3.5 Ma) and the Marsili (1.7-0 Ma) sub-basins. The whole Tyrrhenian basin opened obliquely to the pre-existing alpine orogen. Therefore the main Tyrrhenian architecture and magmatism seem to have been primarily controlled by the composition and thickness of the downgoing subducting lithosphere beneath the Apennines, i.e., continental in the Adriatic and oceanic in the Ionian, and the westward motion of the lithosphere relative to the mantle.