Is the Sicily Channel a simple Rifting Zone? New evidence from seismic analysis with geodynamic implications

Abstract

The Sicily Channel is characterized by the presence of prominent WNW-oriented grabens (Pantelleria, Malta, Linosa Graben) which would point out a main extensional phase within this part of the northern African plate. However, the analysis of both seismic and wells data shows evidence of tectonic reactivation and contractional events in a N-S oriented band crossing the Gela Thrust System and the Malta and Linosa Grabens. We present and discuss the timing of the different deformation phases and their potential geodynamic framework with regard to the regional Africa and Europe convergence. We suggest four main deformation phases affecting the Sicily Channel in Neogene time: 1) a contractional phase, related to the thrusting of the Sicily Fold-and-Thrust Belt in the Upper Miocene, related to the evolution of the regional Western Mediterranean Subduction Zone, 2) an extensional phase with the opening of the main grabens in Lower Pliocene, related to the fast rollback of the Calabrian Slab to the East-Southeast of the Sicily Channel, 3) a Plio-Pleistocene contractional phase with inversion structures within the grabens and onset of transpressive deformation along the Capo Granitola-Sciacca Fault Zone (CGSFZ) and Scicli Ragusa Fault System (SRFS), related to the advance of the Gela Thrust System, and 4) a presently active, mild contractional phase affecting the area between the CGFFZ and SRFS, in particular the Malta and Linosa Graben, which might be related to a regional plate reorganization and potential subduction polarity switch north of Sicily.