Preliminary results of a crustal seismic profile across Sicily (Italy)

The preliminary interpretation of a deep crustal seismic reflection profile, recently acquired in Sicily, on land, from the Tyrrhenian coast to the Iblean foreland (SIRIPRO multidisciplinary research program), will allow to improve the crustal geological model of Sicily.
The data were acquired using dynamite sources with charges up to 30 kg shot in holes at depths down to 30 m. The recording instrument was a Sercel SN 408 XL with 240 channels, an asymmetric to symmetric split-spread recording, 12 km long, according to the presumed and variable structural settings along the line, 110 km long. The acquisition started in December 2007 and was completed in January 2008.
The good quality of the acquired data was already highlighted by the excellent signal/noise ratio recognised in the preliminary seismic section. Conventional processing of the data is now in progress and we are able to present and discuss the first stack version of the entire transect.
The background information available in the area, crossed by the deep crustal seismic profile, consists of recent land geology surveys and deep to crustal seismic reflection data collected in the Sicilian-Maghrebian fold and thrust belt (FTB), as well as the crustal structure of the offshore sector. These data well illustrate the chain setting of the northern Sicily, but were neither able to anchor the thrust pile at depth, nor to define deep crustal geometries, due to the lack of clearly defined crustal information underneath the Sicily mainland.
The preliminary seismic images suggest:
- the occurrence of a 3.5-4 s/TWT-thick carbonate foreland strongly dipping toward north and growing on:
- a 5 s/TWT-deep crystalline basement bounding upwards a 5.5 s/TWT-thick crustal body showing a "layered" structure; - the highly reflective layers bounding, at their base, a discontinuity we interpret as the Moho interface. It appears at about 11 s/TWT depth, at the southern end, and is plunging to the north where it is recognized at 13-14 s/TWT;
- beneath the FTB the already deformed carbonate foreland reaches its maximum depth (6 s/TWT) in central Sicily;
- a complex tectonic edifice composed of a stack of carbonate and terrigenous embricates characterizes the northern part of the transect;
- impressive shallow deformation in the structures extending in the central Sicily Caltanissetta ridge.