Page 2 - 36 Elevation of the last interglacial highstand in Sicily

ARTICLE IN PRESS
4 F. Antonioli et al. / Quaternary International 145– 146 (2006) 3–18
orbital tuning of high-resolution deep-sea oxygen
isotope stratigraphy. According to this stratigraphy,
the geochronological subunit MIS 5.5 occurred between
Termination II (end of MIS 6) and the onset of MIS 5.4,
spanning 133–115 ka (Shackleton et al., 2003). During
this last interglacial period the global sea level rose to a tectonically part of the African Plate. In northeastern
level higher than the modern sea level (Waelbroeck
et al., 2002; Siddal et al., 2003). Reconstructed sea-level
curves, however, vary according to the location as a
result of isostatic changes related to ice-sheet loading
cycles, which can be on the order of several meters
(Lambeck and Chappell, 2001; Lambeck et al., 2002;
Potter and Lambeck, 2004). Along the Italian coasts, the
average level attained by the sea during the MIS 5.5 is
inferred to be $+7 m (Lambeck et al., 2004). Elsewhere
within the western and central Mediterranean Sea, the
validity of sea level markers identified by previous
researchers and the role of tectonic processes is
discussed by Ferranti et al. (this volume).
However, the range of available data on distribution
of MIS 5.5 elevations in Sicily is limited. Therefore this
study assembles previous data, together with new
results, to provide a comprehensive survey of the last
interglacial highstand in Sicily. We aim to expand the
information available on studied sections, provide more
data on elevations of uplifted surfaces, and obtain new
dates on a number of sections and marine fossils so that
the dataset becomes statistically reliable enough to
produce a model. The results are applied to comment
on tectonic controls of uplift in the late Quaternary.
In this paper, the coastline of Sicily is divided into
four coastal sectors and islands (Fig. 1). In Sector 1, in
western Sicily (and Egadi island), MIS 5.5 is recognized
by terraces and notches at +7 to 12 m (Malatesta, 1957;
Fig. 1. DEM of Sicily showing how the coast is divided into sectors for this paper. Numbers are site numbers in Table 1, and are in different colours
for the different geomorphological quality factors. (A ¼ excellent, B ¼ intermediate, C ¼ low).
Antonioli et al., 2002). Sector 2 extends for more than
250 km along the south coast where there is no evidence
of the MIS 5.5 highstand. Sector 3 shows MIS 5.5
features at around +15 m, and differs from Sectors 2
and 4 as it lies on the Hyblean portion of Sicily, and is
Sicily (Sector 4), MIS 5.5 features are all above +100 m,
and as high as +175 m on Mt. Etna volcano (north of
Catania, Monaco et al., 2000). On the volcanoes of
Ustica Island and the Aeolian islands, the MIS 5.5
higstand is found uplifted between +30 and +115 m
(Hearty, 1986; Lucchi et al., 2004a, b). Lampedusa, the
southern Italian island (on the African plate) contains
fossil Strombus bubonius at about +3 m, and thus
appears to be relatively stable (Segre, 1960).
Bordoni and Valensise (1998) compiled MIS 5.5
highstand data for Italian shorelines, reporting 15 sites
in Sicily. In the present work we build on their work and
report a comprehensive review of published papers on
highstand elevations at 36 sites in Sicily, with new findings
from Egadi, Ustica and Lampedusa Islands. We also
present new age data for two important sites at Taormina
and Cefalu` (see Fig. 2 and sites 1 and 24 of Fig. 1).
2. Regional geologic setting
With respect to the MIS 5.5 history, Sicily is divided
into four sectors (Fig. 1), and the setting of each is
briefly described in this section. In general terms, Sector
1 shows good evidence of stability despite a complex
history. Sector 2 is problematic because of rock
preservation problems. However, both Sectors 1 and 2
are currently tectonically more stable than the east coast