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Fig. 2. (a) Schematic reconstruction of the Quaternary stratigraphic units in southern Valdelsa (not in scale), after
Capezzuoli et al. 2007, slightly modified. (b) View of the Torrente Foci valley, east of Campiglia dei Foci, showing
some of the older surfaces of the Quaternary synthems.
travertines' of thermal origin and referred to the
Holocene (Merla & Bortolotti 1967), were later
related to calcareous tufa and assigned to the
Late Pleistocene-Holocene by Capezzuoli &
Sandrelli (2004).
wedge-shaped bodies in the surroundings of hydro-
thermal spring systems. It is characterized by dom-
inantly crystalline fabrics and minor biotic
contribution which reflects the lethal effect of temp-
erature and sulphides on the life of macrophytes
(grasses and trees) and most of the microphytes
(algae and bryophytes). Conversely, calcareous
tufa corresponds to a highly porous, locally
chalky, poorly bedded limestone forming irregu-
larly staked lenticular bodies of massive phytoher-
mal or stromatolitic buildups deposited by ambient
temperature waters in fluvial/palustrine systems
(Pedley 1990, 2009 with references therein;
Riding 1991; Ford & Pedley 1996; Pedley et al.
2003; Glover & Robertson 2003; Capezzuoli &
Gandin 2004). The luxuriant vegetation of emergent
as well as aquatic plants promoted by the abundant
water availability and release of CO
2
, mostly act in a
passive role of support of the microcrystalline pre-
cipitate and rapidly decays upon death, leaving
characteristically porous phytohermal or phytoclas-
tic structures. Cool water tufa and thermal travertine
are not always mutually exclusive in occurrence,
since in the distal end of the thermal-spring
systems cooled waters merge with surface rainwater
or normal-water streams, forming pools where tran-
sitional paludal-like tufas are formed (Ford &
Pedley 1996; Capezzuoli & Gandin 2005; Capez-
zuoli et al. 2008; Pedley 2009).
Terminology adopted to distinguish the tufa
facies follows the more recent genetic classification
which is based on the textural criteria first pro-
posed by Buccino et al. (1978) (D'Argenio et al.
1981; Ord
`
˜ez & Garcia del Cura 1983; Ferreri
1985; Viles & Goudie 1990; Pentecost & Viles
1994; Violante et al. 1994, 1996; Pentecost 1995),
and developed in terms of depositional conditions
by Pedley (1990) and later reviewed by Ford &
Pedley (1996) and Pedley (2009).
Absolute dating has been employed in order to
better constrain the age of the four carbonate
bodies. Dating methods most commonly used to
Materials and methods
The geological/geomorphological survey on the
field, supported by aerial photographs resulted in
the reconstruction of the stratigraphic succession
of the fluvial terraces as well as the distribution
and geometry of the carbonate bodies. The study
of the internal structures and facies associations
has been carried out on outcrops and road cuts
and refined with the help of the sedimentological
and petrographic analysis. Epigean 'flowstones',
described in many works under the general term
'travertine' (Buccino et al. 1978; Juli` 1983;
D'Argenio et al. 1983; Chafetz & Folk 1984;
Ferreri 1985; Brancaccio et al. 1986; D'Argenio &
Ferreri 1988; Lang et al. 1992; Golubic et al.
1993; Demicco & Hardie 1994; Violante et al.
1994, 1996; Pentecost & Whitton 2000; Mart`n-
Algarra et al. 2003) or 'thermogene/meteogene
travertine' (Pentecost & Viles 1994; Pentecost
1995, 2005), today are commonly separated into
travertine and calcareous tufa on the basis of their
constructional, petrological, geochemical and
isotopic characteristics; all of which reflect the
contrasting conditions of deposition related to the
physico-chemical proprieties of the parent waters
respectively derived by an hydrothermal system or
from a fluvial/paludal system fed by cool karstic
springs (Pedley 1990, 2009; Riding 1991; Ford &
Pedley 1996; Guo & Riding 1998; Pedley et al.
2003; Glover & Robertson 2003; Capezzuoli &
Gandin 2004). According to the results of recent
research on active epigean systems (Pedley 1990,
2009; Ford & Pedley 1996; Gandin & Capezzuoli
2008), the term travertine applies to a compact,
well-bedded and laminated limestone,
forming
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