Neogene transpression in the Cefalù Basin (Southern Tyrrhenian): comparison between land and marine data

In NW Sicily, between Cefalu and Palermo, deformations of Messinian-early Pliocene age have been recognised; these are asso­ciated to a dextral transpi-essive tectonics affecting the Apenninic­Maghrebian thrust belt. These deep-seated structures cross through the thrusts front and are connected to the overthrusting of the Maghrebian Chain on the African crust.

In the present paper, the geological and structural data col­lected on-land has been compared with the data deriving from the analysis of the adjacent offshore seismic sections. These correspond to CROP M-6A Section (southern part), MS-3, 91, 102 & 104 Sec­tions and to the public sections of «zone G» (from 92 to 100).

The investigation of the seismic sections confirms the presence of such structures also in the Tyrrhenian offshore, corresponding to the Cefalu Basin; these structures are linked to a regional NW-SE­oriented transpressive zone correlated, in depth, to the passage between sectors characterised by different crustal thickness.

During Messinian-early Pliocene time interval, the early stage of the evolution of the Cefalu Basin is linked to a transpressive tecton­ics; sedimentation takes place within NW-SE lengthened structural depressions, parallel to the crustal shear zone. The later tectonic stage, since the late Pliocene, is mostly transtensive and is connected to the recent evolution of the Tyrrhenian Sea.