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THE SUBMERGED SICILIAN·MAGHREBIAN CHAIN ALONG THE SARDINIA
CHANN EL-SICILY STRAITS BELT

Raimon do Catalano, Salvlna Infuso, Alfonsa Mllla & Atti llo Sulli.
Dipartimento di Geologia e Geodesia, Università di Palermo, via Toti 91, 90128 Palermo, ITALIA.

Abstract
The structura! grain and tector1ic evolution of the NW-SE Sicifian-fv'.aJhrebian sector of the submerged Sardtlia-Sbly a!pidic
bett is described using a reinterpreta!ion of the known seismic grid. The crust is formed of an a!lochtonous belt composed of flysd1
type thrust skes overlying an imbricate wedge composed of basin and platform cartx>nates thrusts deriving from the deformation of

the old Sidfian continental margin. Early MKx:ene to early Pleistocene foredeep terrgenous and clastic cartxmate deposits m!ed

progressively onlawing forelat1d basin during compression. 1imi~ of deformation spanned bwer Mbeeneto bwer Pieist~ne.

lntroduction been thrust eastwards and southeast\vards (Fig. 2).
This paper descnbes the structural grain ot the 4. The foreland area is located in the
Maghrebian-Sicilian sector in the framewol1< of the
Sardinia Sicily alpidic belt (Fig. 1). New well data, southeastem offshore Sicily and in the Sicily Channel. A
dredge hauls and high reso lution monochannel
seismics have been used by us, as well as ok:ler, bwer major acoustically imaged b6dy contains a sedimentary
resolution seismics. succession seen in southem Sidly. Sediments have a

Geologìcal framework Saccense and Hyblean facies domain character
Four main tectonic unns are recognized (Fig. 2). (Catalano, 1987; Catalano et al., 1987, 1989). There
They are geometricalty arranged in a thrust pile verging are important lateral facies variations (Antonelli et al.,
toward the east and southeast. 1988).
1. The highest structurat element occurs along
the Eastern margin of the Sardinia block (Sardinia A thrust front occurs offshore southern Sicily,
Channel, Cornaglia basin) which tectonically overlies between Gela and Sciacca, where the Pleistocene
the "Kabilìan-Calabrian" units (Fig. 3 a.b). The Sardinia sedimentary pad<ages of the Gela basin have been
Thrust Front is \ocated within the Comaglia basin (Torelli intruded by a tectonic wedge of thin skinned thrust
et al., 1985; Catalano et al., 1987, 1989). The Eastem sheets of mostly Oligocene-lower Pleistocene rocks.
Sardinia block is crystalline basement tha! has no! been These form the ··Gela Nappe" seen in southem Sicily
metamorphically overprinted during deformation. Il is (Catalano et al., this vol.). Thrusting started after mddle
unconformably over1ain by thick, presumably Oligocene Pliocene as a conseqJence of transpressional tectonics
to pre -middle Miocene, ctastics that have been on land and continued unti! the earty Pleistocene (0.8
dcformed (Brancolini et al., 1989). Late Miocene- My) deforming progressively the Plio-Pteistocene
Piiocene deposits related to the Tyrrhenian opening toredeep basin (Gela basin. Fig. 1).
unconformably underlie late PEocene-Pieistocene
clastics. The Sicilian Maghrebian sector
Seismic reflection profiles characterize an inner
2. The Kabilian-Calabrian unrts {Fig. 3) consist of strongly shortened segment. which exte nds from
a wedge of imbricated thrusts ot Hercynian crystalline Western Bank southeastwards to the Egadi lslands.
and an outer, less deformed, tectonic element
basement w~h a metamorphic overprint otAlpine age in extending across the Adventure Plateau and the
westem and southem offshore Sicily (Fig. 1, 2). Detailed
Southem Calabria {Compagnoni el al. 1989). They are geologica! seismic sections cross the submerged body
covered by lower Miocene foreland basin arkosic (Fig. 4).
deposits and middle Miocene-Pieistocene clastics, a. The inner sector. The DTF is the northern
characterized by regionat uncontormities {Barbieri et al. boundary of the inner segment of the Sicilian-
1984). The Pliocene-Pleistocene basin filling appears to Maghrebian chain. In this segment the geometrically
be deformed by inversion tectonics (Catalano et al.
1988, Catalano & Milia 1990, Tricart et al. 1990). The highest tectonic un~s srow the rellecting character or a
Kabilian-Calabrian tectonic units overthrust the Sicilian
Maghrebian sector of the chain along the Drepano thinly , layered sequence, which is interpreted as
Thrust Front (DTF) (Catalano et al. 1985, Torelli et at. Numidian flysch or equivalent clastics (Fig. 4). This thin
1986 and Fig. 2, 4, 5). wedge structurally over1ies stacked thrusts sheets that

3. The Sicilian Maghrebid sector consists ot a show the acoustic character ot basinal carbonates

huge tectonic l::xx:ly more than 12 km thick formed from believed to be ? Paleozoic and Mesozoic-Oiigocene in
severa! imbricate thrust units. These locafly involve age (Fig. 6, 8). These rocks bebng to a more irnemal
basement (Torelli et al., 1991). The stacked units have basinal domain. The lower tectonic units, partially

outcropping in the Egadi lslands. are formed ot thk:Kly

bedded Triassic-Liassic carbonates and evaporitic
platform and Jurassic·Oiigocene basinal deposits,

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