<p>The Ligurian Basin is located north-west of Corsica at the transition from the western Alpine orogen to the Apennine system. The Back-arc basin was generated by the southeast trench retreat of the Apennines-Calabrian subduction zone. The opening took place from late Oligocene to Miocene. While the extension led to extreme continental thinning and un-roofing of mantle material little is known about the style of back-arc rifting.</p> <p>To shed light on the present day

more »

... and lithospheric architecture of the Ligurian Basin, active seismic data have been recorded on short period ocean bottom seismometers in the framework of SPP2017 4D-MB, the German component of AlpArray. An amphibious refraction seismic profile was shot across the Ligurian Basin in an E-W direction from the Gulf of Lion to Corsica. The profile extends onshore Corsica to image the necking zone of continental thinning.</p> <p>The majority of the refraction seismic data show mantle phases at offsets up to 70 km. The arrivals of seismic phases were picked and inverted in a travel time tomography. The results show a crust-mantle boundary in the central basin at ~12 km depth below sea surface. The mantle shows rather high velocities >7.8 km/s. The crust-mantle boundary deepens from ~12 km to ~18 km within 25 - 30 km towards Corsica. The results do not map an axial valley as expected for oceanic spreading. However, an extremely thinned continental crust indicates a long lasting rifting process that possibly does not initiated oceanic spreading before the opening of the Ligurian Basin stopped.</p>