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ARTICLE IN PRESS 1569
K. Lambeck et al. / Quaternary Science Reviews 23 (2004) 1567–1598
level have been applied where appropriate. Tidal
amplitudes along the Italian coast are mostly between
0.25 and 0.44 m but locally can reach 1.2 m in the
northern Adriatic at the time of highest astronomical
tide.
2.1. Sea-level markers
2.1.1. Vermetids
Vermetids are a reef building species of gastropods
from lower intertidal habitats. Because of their well-
defined growth zone they provide highly reliable
indicators of sea-level change and of tectonic movement
(Laborel et al., 1994, 1996; Pirazzoli et al., 1996). In the sampling, modern serpulids were living on the outer
Mediterranean Sea, the most common reef-forming
vermetid species is the gastropod Dendropoma petraeum
which can form reefs up to 10 m wide with a depth range
of over 0.40 m. Along the Sicilian coast Antonioli et al.
(1999a) identified platform-type reefs that are similar to
coral fringing reefs and which correspond to the classical
vermetid reefs described by Pe!re"s and Picard (1964).
Vermetids commonly colonize abrasion platforms gen-
erated by wave action and the edge of the resulting
structure is frequently eroded, taking the shape of a
continuous vertical wall 0.4–1 m high. The average age
of a Sicilian reef is less than 600–700 years because their
rapid growth results in a loss of stability and resilience
against storm events. At their time of growth vermetid
reefs are submerged during high tide but remain exposed
during low tide so their position defines the mean sea
level to within the tidal amplitude. For the fossil samples
considered here we adopt error bars equal to the tidal
amplitude plus 0.10 m (Antonioli et al., 1999a).
2.1.2. Cerastoderma glaucum
This Lamellibranchia is frequently found in the
Italian coastal plain in lagoonal deposits both in
outcrops and in cores. In association with other
lagoonal species such as Bittium, Rissoa and Hydrobia,
Lamellibranchia define a typical lagoonal environment
(LEE) bottom (Pe!re"s and Picard, 1964) whose position
with respect to mean sea level is between 0 and À2 m
(Gravina et al., 1989).
2.1.3. Lithophaga
These bivalves live only in calcareous rock, between
low tide level and a depth of no more than 20 m.
However, they live preferentially in the uppermost few
meters, with 90% occurring in the first 2 m below tide
level. They are commonly used as sea-level markers but
unless their living position can be related to morpholo-
gical indicators their associated uncertainty can be large
(>5 m). For example, observations from scuba-dive
transects of sea-floor features below dated fossil out-
crops determine the depth range of living species and,
together with seabed profiles, determines the maximum
depth limit of the fossils at the time of their growth
(Antonioli et al., 2003). Where such supplementary
observations have been made the lower limit is
determined by the sea-floor profiles at the site.
2.1.4. Speleothems with marine overgrowth
For some limestone sections of the coast caves occur
that are now flooded. During lowstands, speleothems
formed but as the caves flooded during the sea-level rise
their development ceased and they became encrusted
with colonies of the marine worm Serpula massiliensis.
These gregarious worms typically form thick marine
crusts composed of calcitic tubes. At the time of
surface of the speleothem. By dating both the first
serpulid layer and the last continental layer, Alessio et al.
(1996) obtained the time of submergence at the altitude
of sampling. Because serpulid growth rates are very slow
the 14C ages are often time-integrated values and a linear
growth model is adopted to arrive at a model age for the
oldest encrustration (Alessio et al., 1992). In some
speleothems the age of flooding is provided by
Lithophaga that bored into the continental layer and
were found to be completely covered by the overgrowth.
In this case the age of the mollusc is considered to date
the first marine colonization of the speleothem and the
earliest stage of submersion (Antonioli and Oliverio,
1996). However, a hiatus of 2 or 3 ka is sometimes found
between the ages of the continental deposits and the
oldest recorded lithophaga so that the ages are limiting
values only.
Lithophaga growth is relatively slow, typically 8 cm in
80 years and the results used in this study are only from
specimens less than 3 cm in length. Thus age-of-growth
uncertainty from sampling is at most 30 years, less than
the typical 14C measurement precision. The speleothem
depths have been determined with a digital depth gauge
that has a typical error of 70.1 m. Down-growing
speleothems have been sampled near their lower limit
and up-growing speleothems have been sampled near
their upper limit and the maximum positional uncer-
tainty is better than 0.5 m.
2.1.5. Cores containing marsh or biological markers
Biological markers from core samples have provided
satisfactory results when the cores are from sandy
sediments for which compaction has been minimal. In
these cases the depth precisions are determined by the
accuracy of the relationship of the biological marker to
mean sea level. This is the case for the ENEA core (1)
discussed below. However, because of a range of
potential uncertainties associated with the interpretation
of single core records we add an uncertainty of 1 m to all
precision estimates. Where the cores are from marsh
deposits compaction may be important and the posi-
tional uncertainty of the biological markers may be