Layered lower crust and mantle reflectivity as imaged by a re-processed crustal seismic profile from Sicily in the central Mediterranean

Abstract

Though Sicily is a key area for understanding the central Mediterranean tectonics, a number of questions on its dynamics remains open due to the lack of detailed data on the lithospheric structure. Deep reflectivity images of the African lithosphere, beneath Sicily, have been derived from the re-processing of the crustal seismic reflection stack (SI.RI.PRO. Project). Of specific interest was the imaging, beneath central-southern Sicily, of a thinned crust with a reflective, “layered” pattern for the lower crust that differs from the one, thicker and sub-transparent, of the northern-central sector. Brittle deformation in the upper crystalline crust along a low-angle normal fault and sub-horizontal sub-Moho events are the main features, spatially associated with the “layered”, attenuated lower crust. Geological implications, which are related to the above-mentioned crustal characters, that allow us to suppose two combined hypotheses (the first suggesting that the crustal features derive from the effects of Permian and Mesozoic rifting cycles, the second connecting the crustal thinning to the latest Pliocene-Pleistocene volcanic activity and tectonics), are here discussed. The imaging of the Moho patterns and the crustal/sub-crustal reflectivity characteristics, here illustrated for the first time, could provide constraints for the geodynamic processes governing this area where an interaction between African and Tyrrhenian European plates occurs.