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ARTICLE IN PRESS
L. Ferranti et al. / Quaternary International 145– 146 (2006) 30–54
bulge in post-MIS 5.5 times is consistent with the long-
term history of the region, characterized by uplift of
middle Pleistocene terraces (Amato, 2000), possibly
related to the nucleation of folds and thrust faults
in the crystalline basement of the region (Ferranti
and Oldow, 2005a, b). Similar long-wavelength folds
characterize Murge and Gargano, and a small lateral
variability of the marker elevation might mirror this
tectonic pattern (Fig. 12). Holocene uplift is reported
on the northern Gargano shore (Mastronuzzi and
Sanso` , 2003), and thus testifies to recent and possibly
modern uplift.
5.9. Central Adriatic
The central Adriatic coastline from Molise to Emilia-
Romagna runs parallel to the foothills of the central
Apennines thrust belt, which is still tectonically active
beneath the coastal region and the Adriatic Sea (Lavec-
chia et al., 1994; Frepoli and Amato, 1997; Vannoli et al., northern Apennines thrust belt (Fig. 5a and 8). Thus, the
2004). Despite efforts to study MIS 5.5 deposits (Parea
and Valloni, 1983; Molinaroli, 1984; Parea, 1986), the
understanding of MIS 5.5 markers along the Abruzzi and
Molise coasts (Fig. 4) is limited, and does not allow yet
determination of ages and altitudes.
Further north, along the Marche and southern Emilia
coastline, MIS 5.5 marine terraces are found between 7
and 16 m a.s.l. (Fig. 8; sites 237–239 in Fig. 4), with
differential uplift related to segmented growth of
anticlinal folds (Vannoli et al., 2004). The slow coastal
uplift resulting from the marker’s altitude confirms the
model of the long-term and present-day tectonic regime
of the area, which is compressional along the front of
the Apennines (Fig. 5a and b).
5.10. Northern Adriatic
North from the slightly uplifted terraces of the
Marche region, the MIS 5.5 marker is strongly down-
dropped at the northern Adriatic coast. The marker is
recovered in boreholes between À85 and À117 m b.s.l. in
the northern Emilia-Romagna region (Fig. 8). The
marker is here represented by a wedge-shaped littoral
sand body, which can be traced by borehole correlation
Table 2
Analytical data for the new ESR ages for Po` Plain cores
Site Lab. no. H2O (Sed.) U-cont. Th-cont. K-cont. (Sed.) U.cont (foss.) De (Gy)
(%) (Sed) (ppm) (Sed) (ppm) (%)
205-S10 K-4383 30 2.870.2 6.970.6
240-S8 K-4384 30 1.0670.1 6.570.5
222-S2 K-4385 30 3.570.2 8.570.6
The surface of the mollusk shells was cleaned with acid. The ages have been calculated using the early uptake model (computer programme DATA
VII from Rainer Gru¨ n, Canberra, Australia). De is the equivalent dose (‘‘accumulated dose’’), Do is the ‘‘annual dose’’ (the dose of radiation a
samples receives during a year).
45
up to 30 km inland from the modern shoreline (Amorosi
et al., 1999a, b, 2004). Attribution of the deposit to the
last interglacial is based on pollen series correlation (e.g.
Tzedakis et al., 1997), which provides an MIS 6 age for
the alluvial plain deposits underlying the beach sands
(Amorosi et al., 1999a, b, 2004). The lateral continuity
of the littoral sediment suggests that it developed during
the main 5.5 highstand, cautiously supported by new
ESR age data on shells (Table 2).
Consequently, significant tectonic subsidence occurred
since around 125 ka. Quantification of the subsidence
rates, however, is not straightforward, since large
uncertainties exist for both the age and the paleo-shoreline
position of the sampled deposits. Given all the above
uncertainties, a subsidence of 0.8–1.0 mm/a is reasonable.
The boreholes are located in the southern margin of the
Po plain, which represents the foredeep basin for the active
subsidence pattern of the MIS 5.5 marker in northern
Emilia-Romagna indicates flexure probably associated
with the compression occurring on the northern Apen-
nines front, which underlies this location. These sites are
located in the hanging-wall of the thrust front (Ferrara
arc, Fig. 8) but, unlike sites further south, they experience
strong subsidence instead of mild uplift (Fig. 8).
Two sites located further north in Veneto and Friuli
(Fig. 8; sites 239 and 240, Fig. 4), although having a very
high uncertainty regarding age and shoreline position,
display less subsidence relative to the Emilia-Romagna
sites. These two northern sites are closer to the northern
side of the Po Plain, and thus might indicate flexure
related to the Southern Alpine and Dinaric contraction
(Fig. 5a, b and 8).
6. Discussion
6.1. Tectonic models for displacement of the MIS 5.5
marker
The different altitudes at which markers of the MIS
5.5 highstand have been placed by tectonic movements
have been used to propose models of regional deforma-
tion in Italy. By compiling the altitude of 31 outcrops
Do (mGy/a) ESR age
(ppm) (ka)
1.5870.1 0.570.2 163.09718.91 13187148 124720
1.3170.1 0.570.2 129718
1.370.1 0.570.2 126.6477.92 9937127 154726
209.51 13647168