Page 9 - Sulli_eall_2012

Variability of depositional setting along the north-western Sicily continental shelf (Italy) ... 149

Fig. 9 - Seismic section crossing the Palermo Salient (offshore Bay of Carini). The seismic profile (Sparker 1 kJ) shows both the upper
slope and the continental shelf where two distinct sectors can be separated; a prominent break-in-slope divides the two sectors. Along
the outer shelf the sea floor is sub-horizontal, in the inner shelf it assumes an about 1.5° slope. According to our interpretation, the top of
acoustic basement corresponds to the base of Plio-Pleistocene sequence. This horizon is affected by folding and reverse faults. Inside
the Plio-Pleistocene sequence, a prominent unconformity separates two seismostratigraphic units. The lower one (Zanclean in age?)
displays a predominant reflection-free seismic facies and appears deformed.

Fig. 10 - Seismic reflection profile (Sparker 1 kJ) at the north-east end of the Palermo salient. Here the continental shelf widens to 8.5
km and displays a very irregular morphology characterized by an inner and an outer sectors separated by a prominent break-in-slope
partly buried beneath a stack of prograding sedimentary wedges. These downlapping, regressive deposits does not extend to the shelf
margin where a landward sloping abrasion surface outcrops at the sea bed.

LQDS lower boundary, cut through by a sharp network tors and in rare cases oblique-parallel. Reflectors show
of incisions (Fig. 11), connecting the mainland incised medium amplitudes and are interrupted by rotational
valleys to the main submarine canyons. faults or affected by slope failures (Fig. 11). The ampli-
tude and the lateral continuity of seismic horizons de-
The FSST has been identified in the outer shelf crease seawards.
(Fig. 11), where it onlaps the LQDS lower boundary, at
an average distance of 9 km from the present shoreline, A shelf margin wedge forming the LST (Fig. 11) is
and at depths of 110-120 m. The prevalent seismic faci- situated in the eastern and central sector of the gulf,
es is characterised by complex sigmoid-oblique reflec- near the present-day shelf edge, and in the upper slope.