Page 16 - UNEP_MAP2015

According to Civile et al. (2008) and Civile et al. (2010), neogene rifting caused the
development of three major depressions (grabens, basins or trough), the Pantelleria (1317-m
depth), Linosa (1529-m depth), and Malta (1731-m depth), located in the central basin of the
channel.

The Pantelleria graben, southeast of Pantelleria Island, is one of three narrow, steep-walled,
elongate NW–SE troughs in the Channel. Pantelleria Trough has almost straight, fault-
bounded slopes, over 100 km long and 28 km wide, with depths reaching 1314 m. Two fault
valleys, running parallel and trending to southeast, cut the eastern end of Pantelleria basin.

One is the Linosa trough at the southern extremity of a graben system that trends south
eastward from Linosa Island and probably is continuous with the Medina graben. At the
eastern end of the Linosa graben three volcanoes raise from a depth of 500-700 m (Linosa I,
II, III seamounts). The other valley is the Malta graben that trends parallel to the Linosa
graben on its north-eastern side and to the south west of Malta. At its western end the
Bannock seamount raises from about 800 m to 280 m depth, separating Malta graben from
Pantelleria graben. The Malta graben separates Medina bank and Melita bank from the Malta
platform on the north, which is part of the Pelagian block. Between these grabens is the
prominent horst of the Malta seamount. A southward trending branch of the Malta graben,
the Melita-Medina graben, separates the Melita bank from the Medina bank (Bishop and
Debono, 1996).

In the southeastern parts of the Sicily channel, the African continental shelf is very wide and
covers more than a third of the areal extent of the channel itself. In the Gulf of Gabes, the
bathymetry is shallower than 30 m for large stretches away from the coast. This are
correspond to submerged part of the Pelagian Province (Fig. 1) and encompasses other
several major geologic structures. Among the more pronounced structural highs are the
Lampedusa Plateau and Isis Horst.

The Ashtart-Tripolitania Basin (also called Gabes-Tarabulus Basin), Misratah Valley, Jarrafa
graben are the major depressions. Fault systems, developed earlier in the Pelagian Province
area (south of the Pantelleria graben, Malta graben, Malta graben), continued to sub-side
and control deposition (Klett, 2001). Locally, relatively greater amounts of subsidence
occurred in the Gulf of Hammamet. Orogenic movement is presently occurring in northern
Tunisia (Burollet and others, 1978).

As an extensive, largely submarine platform, the Pelagian province is bounded on the
northeast by the Ionian abyssal basin along the Malta escarpment, a system of normal faults
of post-Miocene age that probably follows an older crustal fracture zone, and on the east –
south east by the Sirte rise and the upper Sirte slope. The northern limit of the Pelagian
province is the Calabrian fore-arc thrust zone, and on the northwest is the compressive
Magrebid trend of Cap Bon. The Pelagian block was a stable promontory of the African

13