Morphostructural Setting and Tectonic Evolution of the Central Part of the Sicilian Channel (Central Mediterranean)

Abstract

The Plio-Quaternary tectonic evolution of the central sector of the Sicilian Channel and the resulting morphostructural setting have been analyzed using a large geophysical dataset consisting of multichannel seismic profiles, which some of them never published, and available bathymetric data. This area hosts two regional-scale tectonic domains that registered the complex pattern of deformation occurred since the Early Pliocene: (1) the Sicilian Channel Rift Zone (SCRZ), which can be divided into a western sector formed by the Pantelleria graben (PG) and in a eastern one represented by the Linosa and Malta grabens (LG and MG) and (2) the Capo Granitola-Sciacca Fault Zone (CGSFZ), a NNE-oriented lithospheric transfer zone that crosses the Sicilian Channel from the Sicily coast to the Linosa Island, of which only its northern part has been studied to date. Data interpretation has allowed achieving the following outcomes: (i) the presence of an alternation of basins and structural highs forming a NNE-oriented separation belt between the western and eastern sectors of the SCRZ, and interpreted as the shallow expression of the southern part of the CGSFZ; (ii) a NE-oriented tectonic lineament separating the MG in a northern and southern part, and interpreted as the southern prosecution of the Scicli-Ragusa Fault System; (iii) the presence of syn-rift deposits in the Plio-Quaternary fill of the grabens, suggesting that the opening of the grabens of the SCRZ was coeval, and started since Early Pliocene in the framework of a NW-oriented right-lateral transtensional mega-shear zone; (iv) continental rifting ended around the Early Calabrian, during which extensional tectonics dominated along the separation belt; (v) the CGSFZ conditioned the SCRZ configuration at a regional scale, leading to the development of the PG in the western sector and of the LG and MG in the eastern one; and (vi) after the Early Calabrian, the PG and the southern MG followed a different tectonic evolution with respect to the LG and northern MG. The syn-rift deposits of the PG and southern MG were sealed by an undeformed post-rift succession, while the LG and the northern MG suffered a basin inversion that ended around the Latest Calabrian time. During this stage, the separation belt was affected by a transpressional tectonics. At present, the grabens of the Sicilian Channel seem to be tectonically inactive, while the CGSFZ represents an active tectonic domain.

Palaeo-Shoreline Configuration of the Adventure Plateau (Sicilian Channel) at the Last Glacial Maximum

“…Similar values have been reported analyzing morphological elements onshore [25]. This sector of the Sicilian Channel is affected by the Capo Granitola and Sciacca fault systems, which are part of a lithospheric-scale strike-slip fault zone running roughly N-S and crossing most of the Sicilian Channel [26][27][28]. However, this structure does not significantly influence the tectonic context of the study area since it is located about 20 km to the east of the margin of the Adventure Plateau on which we have concentrated our analyses.…”

Basic Role of Extrusion Processes in the Late Cenozoic Evolution of the Western and Central Mediterranean Belts

“…Further support to the above interpretation is given by the fact that tectonic activity in Sardinia mainly developed from the lower-middle Pliocene to the Pleistocene, (e.g., [166][167][168]), i.e., the period during which the northward displacement of the Adventure wedge and the consequent displacement of the Alpine-Maghrebian belt were taking place. The sinistral shear here proposed in the Sicily Channel transtensional fault system is suggested by other authors (e.g., [183,184]), whereas a dextral shear is proposed in other papers (e.g., [146,153,179,[185][186][187]). However, this last hypothesis is not compatible with major pieces of evidence in the surrounding zones.…”

“…Such presumed kinematics would have caused compressional deformations somewhere in the Ionian zone, where instead no evidence of this effect is recognized, especially at the Syracuse escarpment, (e.g., [188]). Fur- The sinistral shear here proposed in the Sicily Channel transtensional fault system is suggested by other authors (e.g., [183,184]), whereas a dextral shear is proposed in other papers (e.g., [146,153,179,[185][186][187]). However, this last hypothesis is not compatible with major pieces of evidence in the surrounding zones.…”

“…The small zones where the plateau fragments diverged from each other underwent crustal extension, forming the Malta and Linosa grabens and other minor troughs (Figure 8C,D). This context lasted until the complete consumption of the Gela thinned domain, around the Early Pleistocene [179], which determined a considerable slowdown of extensional deformation in the Linosa and Malta troughs [179].…”

Unraveling Past Submarine Eruptions by Dating Lapilli Tuff-Encrusting Coralligenous (Actea Volcano, NW Sicilian Channel)

“…This sector of the Sicilian Channel is characterized by a widespread and scattered anorogenic volcanism which occurred mainly during Quaternary, with the build up of the islands of Pantelleria and Linosa, and the formation of a series of submarine edifices located in eastern Adventure Plateau, within Graham Bank and the nearby Terrible Bank and, as recently discovered, a few nautical miles off the SW coast of Sicily (Figure 1; Calanchi et al, 1989;Rotolo et al, 2006;Civile et al, 2015;Coltelli et al, 2016;Cavallaro and Coltelli, 2019;Lodolo et al, 2019a). Part of this volcanism is related to the Pliocene rifting process that produced the grabens of Malta, Linosa, and Pantelleria (Boccaletti et al, 1987;Ben-Avraham et al, 2006;Civile et al, 2010Civile et al, , 2014Civile et al, , 2021Lodolo et al, 2012; among others), and part is linked to the presence of a NNE-trending, lithospheric transfer zone named Capo Granitola-Sciacca Fault Zone, which traverses the central sector of the Sicilian Channel (Calò and Parisi, 2014;Fedorik et al, 2017;Civile et al, 2018;Ferranti et al, 2019;Palano et al, 2020). High-resolution bathymetric data have shown that most of the volcanic centers in the Graham Bank, lying at 150-250 m water depths, are monogenetic tephra cones (Cavallaro and Coltelli, 2019) aligned with the Capo Granitola Fault System (CGFS).…”