Page 13 - 36 Elevation of the last interglacial highstand in Sicily

ARTICLE IN PRESS
F. Antonioli et al. / Quaternary International 145– 146 (2006) 3–18
10
0 7.1
-10 5.1 5.3
-20
-30 146.8 ±28.7
-40
-50
-60 m 5.2 5.4
-70
-80 mean EU age:
88.2 ±19.5
-90 4
-100
-110
-120
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
-130
0
Fig. 9. Waelbroeck et al. (2002) sea level curve with the ESR data and error bars.
dating (between 92.175 and 180.2710.8 ka concluded:
‘‘the age variations observed between different teeth is
not consistent with their stratigraphic ordering within
the site. The most likely date for the samples is between
the EU and LU model ages, from late oxygen isotope
stage 6 to early oxygen isotope stage 4’’. However, if we
consider not only the ‘‘youngest’’ age of the continental
samples, but all the EU and LU ages published by
Rhodes (1996), and if we compare these data with a
global sea level curve (Fig. 9, Waelbroeck et al., 2002),
the Rhodes ages (including error bars) do not appear to
allow a precise interpretation of the age of the terraces.
Thirdly, we disagree with the Bianca et al. (1999)
interpretation that the ESR data strongly suggests that
the Akradina terrace and deposits should be correlated
to the MIS 5.1 highstand. We are concerned that ESR
dating produces ages with an uncertainty range of the
order of 720 or 30 ka. This dating technique should be
used only when other methods are ruled out. This is not
the case for the coast at Augusta (10 km from Contrada
Fusco); Di Grande and Scamarda (1973) and Di Grande
and Neri (1988) found more than one S. bubonius in situ
in a normal fossil beach containing many circalittoral
fossils, this deposit occurs on a well-defined terrace with
a inner band of lithophaga borings that reaches +16 m.
In this same coastal site Bianca et al. (1999) put the MIS
5.5 terrace at 60 m, apparently ignoring the terrace
containing S. bubonius, the well-known Mediterranean
marker of this marine highstand. In view of the above
points we prefer not to use the datum of Contrada
Fusco, so therefore the inner margin at 32 m is
correlated to MIS 5.5. We use the elevation of the
MIS 5.5 terrace at Augusta–Monte Tauro that occurs at
(footnote continued)
that all uranium in the tooth was adsorbed early in the burial history, macropalaeontological content of the deposits that
whereas in the linear uptake (LU) model it is assumed that the uptake
was continuous and constant throughout the burial history.
15
5.5
mean LU age:
6.5
Age, ka and M.I.S.
an elevation of 16 m, well controlled by the Lithophaga
band.
For the sites at Taormina (24), Capo d’Alı` (25) and
Capo Peloro (26) we consider elevations of, respectively,
115, 140, and 110 m to be correct for the inner margins
of these ‘‘Tyrrhenian’’ terraces. This disagrees with the
Catalano and De Guidi (2003) and de Guidi et al. (2003)
estimates for the elevations of the same places that
employ a different geomorphological interpretation to
arrive at inner margin elevations of 180, 210 and 140 m
for MIS 5.5. We base our interpretation on field surveys
of the inner margins in the Taormina area (Figs. 5 and
3C, D) study of 1:10.000 aerial photographs, and the
ESR age of the fossils sampled at 105 m on the 31 order
terrace (Fig. 4). We also visited the cave described by
Bonfiglio (1981) and found inside the cave at 140 m the
Vermetid (Dendropoma) reef described in the Bonfiglio’s
paper. This deposit, however, is not associated with any
terraces. For sites 25 and 26 we studied aerial photo-
graphs and, on geomorphological grounds, made a
correlation with the terrace at Capo Peloro that contains
S. bubonius and preserves the inner margin at 110 m.
The explanation of why the South coast does not
preserve evidence of uplift remains uncertain, although
there are at least two different interpretations: (1) the
relatively weak bedrock is easily eroded and possible
terrace features and recent sediments have not been
preserved, (2) there is tectonic subsidence. We believe
the second of these possibilities could be correct: the
Grande Terrazzo Superiore (GTS) studied by Ruggieri
and Unti (1974) is a very wide terrace (probably
polygenic in origin) well developed on W and SW coasts
of Sicily (Fig. 1). On the basis of the micro- and
overlie this terrace, and on the lithologies into which
the terrace is cut, Ruggieri et al (1975) considered it to
be younger than the Calcarenite di Marsala (of Sicilian
age, about 930 ka) and older than the first Middle