Page 1 - Cipriano_Madonia_alii_2017

GEOLOGICA CARPATHICA, FEBRUARY 2017, 68, 1, 80 – 93 doi: 10.1515/geoca-2017-0007

Geomorphological evolution of western Sicily, Italy

CIPRIANO DI MAGGIO, GIULIANA MADONIA, MARCO VATTANO,
VALERIO AGNESI and SALVATORE MONTELEONE

Università degli Studi di Palermo, Dipartimento di Scienze della Terra e del Mare, via Archirafi 22, 90123 Palermo, Italy;
cipriano.dimaggio@unipa.it, giuliana.madonia@unipa.it, marco.vattano@unipa.it, valerio.agnesi@unipa.it, salvatore.monteleone@unipa.it

(Manuscript received February 24, 2016; accepted in revised form November 30, 2016)

Abstract: This paper proposes a morphoevolutionary model for western Sicily. Sicily is a chain–foredeep–foreland
system still being built, with tectonic activity involving uplift which tends to create new relief. To reconstruct the
morphoevolutionary model, geological, and geomorphological studies were done on the basis of field survey and aerial
photographic interpretation. The collected data show large areas characterized by specific geological, geomorphological,
and topographical settings with rocks, landforms, and landscapes progressively older from south to north Sicily.
The achieved results display: (1) gradual emersion of new areas due to uplift, its interaction with the Quaternary
glacio-eustatic oscillations of the sea level, and the following production of a flight of stair-steps of uplifted marine
terraces in southern Sicily, which migrates progressively upward and inwards; in response to the uplift (2) triggering of
down-cutting processes that gradually dismantle the oldest terraces; (3) competition between uplift and down-cutting
processes, which is responsible for the genesis of river valleys and isolated rounded hills in central Sicily; (4) continuous
deepening over time that results in the exhumation of older and more resistant rocks in northern Sicily, where the higher
heights of Sicily are realized and the older forms are retained; (5) extensional tectonic event in the northern end of Sicily,
that produces the collapse of large blocks drowned in the Tyrrhenian Sea and sealed by coastal-marine deposits during
the Calabrian stage; (6) trigger of uplift again in the previously subsiding blocks and its interaction with coastal processes
and sea level fluctuations, which produce successions of marine terraces during the Middle–Upper Pleistocene stages.
Keywords: Sicily, geomorphological evolution, Quaternary, uplift, extensional tectonics, down-cutting processes,
differential erosion.

Introduction transpressive deformation occurred, and extension took place
in the Tyrrhenian Sea as the shortening and thrusting in the
Sicily is located on the Pelagian promontory of the African arcuate Apennines–Sicily, east- and southward-directed
plate and is formed by the Iblean foreland, the Gela foredeep, orogens. The extensional deformation propagates towards
the thick Sicilian orogen, and the thick-skinned Calabrian– the SE associated with the fast retreat and roll-back of the
Peloritani wedge (Fig. 1). NW-dipping subduction of the Adria–Ionian plate underneath
Previous geological studies have shown that the fold and Calabria (Malinverno & Ryan 1986; Doglioni et al. 1999;
thrust belt of Sicily was formed in the context of the complex Pepe et al. 2005; Carminati & Doglioni 2012 and references
roll-back of the African–Pelagian slab that was associated first therein).
with the counter-clockwise rotation of Corsica and Sardinia According to the plate tectonic setting, the topography and
and the subsequent clockwise rotation of the Calabria– geomorphology of Sicily is the result of constructive (tec-
Peloritani–Kabylian units, during the late Neogene (e.g., tonic) and destructive (erosional) forces following the colli-
Rosenbaum et al. 2002; Carminati et al. 2012; Catalano et al. sion between the African and European plates, that produced,
2013; Vitale & Ciarcia 2013). Various Authors have described among other things, the Sicilian Mountains.
the ages of the orogenic construction of the Sicilian chain Previous geomorphological studies have been performed
(e.g., Avellone et al. 2010; Catalano et al. 2013 and references since the first half of last century (e.g., Cipolla 1933) and have
therein) within the framework of the evolution of the Apennine undergone a boost in recent decades. They deal with the recon-
orogen (e.g., Ciarcia et al. 2009; Ascione et al. 2012; Ciarcia struction of the geomorphology of small areas (e.g., Mauz et
& Vitale 2013). From the upper Oligocene, the orogenic con- al. 1997; Di Maggio et al. 1999) or specific thematic studies
struction started with the accretion of the Calabria-Peloritani (e.g., Ferrarese et al. 2003; Di Maggio et al. 2012, 2014;
wedge, and the deposition of flysch (e.g., Numidian flysch) in Madonia et al. 2013; Vattano et al. 2013; De Waele et al.
foreland basins. During the Early–Middle Miocene the defor- 2016).
mation of the internal zone occurred, with a first tectonic event Hugonie (1982) carried out studies on a regional scale and
characterized by shallow seated thrusting; at the same time, proposed a morphoevolutionary model for northern Sicily,
the first wedge-top basins developed. From the Late Miocene, emphasizing the role of both structure and climate. Hugonie
a second tectonic event characterized by deep-seated (1982) imputed to the Plio–Quaternary tectonic phase, the

www.geologicacarpathica.com