Page 1 - CatalanoInfuso&Sulli_1995

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Tectonic history of the submerged M aghrebian Chain
f rom the Southern Tyrrhenian Sea to the Pelagian
Fo rela nd

Raimondo Catalano*, Salvina Infuso and Attilio SuIli
Dipartimento di Geologia e Geodesia, Università di Palermo, 90128 Palermo, Italy

ABSTRACT geometries and improve our knowl-
edge of the internai organizatìon of the

A description is given here of the structure and tectonic evolution of the main thrust pile in the NE Sicily Straits
submerged NW-SE trending Alpine belt extending from the Sardinia and its latera! eastern extension (i.e. the
Channel across the Sicily Straits to the Pelagian Sea. This mainly results NW Sicily contìnental margìn). This
from re-interpretation of the existing seismic network. In the Sicily allows us to defìne the relatìonshìp
between the Gela foredeep and its main

Straits the crust comprises an allocthonous belt composed of Tertiary thrust front, and also reveals the Plio-
flysch-type thrust slices stacked in an imbricate wedge. The wedge is Pleistocene tectono-sedimentary evolu-
composed of Mesozoic basin and platform carbonates thrusts derived tìon of the eastern side of the Pelagìan
by deformation of the old Sicilian continental margin. Lower Miocene to platforrn (Malta-Linosa area).

Lower Pleistocene foredeep deposits (terrigenous and clastic GEOLOGICAL FRAMEWORK
carbonates) filled progressively onlapping foreland basins during

regional compression. In the southem Sicily offshore the deformation The area studied in the Centrai Western

spanned early Miocene to early Pleistocene time. The structural Mediterranean is a part of the NW-SE
evolution of the Gela foredeep shows the kinematics and timing of Alpine segment extending from the
emplacement of the 'Gela Thrust System', that is believed to be the Sardìnìa Channel across the Sicily
present-day thrust front of the Sicilian accretionary wedge. In the Sicily Straits to the Pelagìan Sea (Fig. 1). It
Channel, the Plio-Pleistocene tectono-sedimentary history of the represents a submerged segment of the
Lampedusa-Linosa sector reveals evidence of middle Pliocene regìonal Tertiary Africa-Europe suture,
extensional tectonics, and indicates a rift mechanism far formation of linkìng the African Maghrebids to the
Sicilian orogen.

the Sicily Channel. This event was followed by inversion tectonics and Four main tectonìc unìts are recog-
strong vertical tectonics in the late Pleistocene. nized in this mostly submerged area
(Fig. 2), arranged as a thrust pile

Terra Nova, 7, 179-188, 1995. vergìng toward the east and south-east:
l The hìghest structural element occurs

INTRODUCTION along the eastern margìn of the Sardìnìa
Torelli et al., 1991; Torelli et al., 1992). block (Sardìnìa Channel, Cornaglia

•· In the last few years severa! studies These papers describe the main stratì- basin). This tectonìcally overlies the
have been published of the marine graphìc and structural features, and 'Kabilian-Calabrian' unìts along the

geology of the Sardìnìa Channel-Sicily often provìdìng more-or-less schematìc Sardìnìa Thrust Front and is located
Straìts regìon (Fig. 1), maìnly based on deep geologìcal sectìons of the area. wìthìn the Cornaglia basin (Torelli et al.,
multìchannel seismìc profiles calibrated Some of these works focused on the NW 1985; Catalano et al., 1989). The Eastern

by well logs, dredge hauls and other Sicily Straits and southern Sicily off- Sardìnìa crystalline basement was not

geophysìcal methods (Barbieri et al., shore and demonstrated dose relatìons metamorphosed during deforrnatìon,

1984; Finettì, 1984; Torelli et al., 1985; between the regìonal tectonìcs of Sicily and is unconforrnably overlain by

Catalano, 1987; Catalano et al., 1989; (Catalano and D'Argenìo, 1982) and the thìck, deforrned, clastìcs of presumably
Antonelli et al., 1988; Argnanì, 1989; adjacent submarine region (Catalano et Aquìtanìan-Lower Burdigalian age
Argnanì et al., 1989; Tricart et al., 1990; al., 1989; Catalano, 1988; Argnanì et al., (Brancolini et al., 1989; Compagnoni et
al., 1989; fig. 3b in Catalano et al., 1993c).
1989).

New hìgh-resolutìon and multìchan- Upper Miocene-Pliocene deposits, re-

•correspondence: Dipartamento di Geolo- nel seismìc profiles, well data and lated to the Tyrrhenìan Sea openìng

gia e Geodesia, Unìversita di Palermo, via dredge hauls from the Sicily Straits unconforrnably underlie Upper Plio-
Toti, 91, 90128 Palermo, Italy. Fax: +39/91 and the Pelagian Sea now allow a re- cene-Pleistocene clastics (Barbieri et al.,

65 71 406. interpretatìon of seismìc facies and 1984);

© 1995 Blackwell Science Ltd. 179