Key features of mixed carbonate-siliciclastic shallow-marine systems ...

44-R2 – ZECCHIN
Ital.J.Geosci. (Boll.Soc.Geol.It.), Vol. 130, No. 3 (2011), pp. 370-379, 10 figs. (DOI: 10.3301/IJG.2011.12)
© Società Geologica Italiana, Roma 2011
Key features of mixed carbonate-siliciclastic shallow-marine systems:
the case of the Capo Colonna terrace (southern Italy)
ABSTRACT
The late Pleistocene Capo Colonna terrace (southern Italy) is
composed of a mix of shallow-marine carbonate and siliciclastic sediments.
Shoreface sandstones, dominated by a terrigenous component
and by sedimentary structures related to waves and currents,
pass seaward into shelf coralline algal frameworks and associated
calcarenites. Siliciclastic sandstones and rigid bioconstructions are
locally juxtaposed. Main features of the studied system include (i) a
bipartition between mixed siliciclastic-bioclastic sedimentation in
proximal settings and coralline algal growth in distal settings, (ii) an
analogy between the stratal architecture of the clastic-dominated
part of the system and that of siliciclastic shelf/ramp systems, and
(iii) the control on the gradient of the shoreface-shelf by inherited
physiography and transgressive processes rather than the carbonate
productivity.
KEY WORDS: Mixed carbonate-siliciclastic shallow-marine
system, marine terrace, Capo Colonna, Crotone, Cala -
bria, Pleistocene.
INTRODUCTION
Various studies highlighted that carbonate and siliciclastic
systems exhibit peculiar features and respond in
a different way to forcing processes (SCHLAGER, 1991;
POMAR, 2001a; ZECCHIN, 2007; POMAR & KENDALL, 2008).
The architecture and morphology of carbonate systems is
strictly controlled by the interplay between carbonate
productivity, which is in turn conditioned by climate,
terrigenous supply, physiography, oceanography and
trophic and chemical factors, and changes in accommodation
(SCHLAGER, 1991, 1993; POMAR, 2001a; POMAR &
KENDALL, 2008). In these systems, therefore, optimum
conditions for the carbonate factory generally allow carbonate
deposits to keep pace with relative sea-level rises,
and this determined the accumulation of successions characterized
by stratal architectures that may be signi ficantly
different from those of silicilastic deposits (SCHLAGER,
1991, 1993; BETZLER et alii, 1997). In siliciclastic systems,
terrigenous supply, relative sea-level changes, physiography
and hydrodynamics are the main controlling factors,
producing variable stratal architectures (ZECCHIN, 2007).
Mixed carbonate-siliciclastic shallow-marine systems show
sedimentary features along depositional profile that are not
still set in univocal mo dels (MOUNT, 1984; BRANDANO &
(*) Istituto Nazionale di Oceanografia e di Geofisica Sperimentale
- OGS, 34010 Sgonico (TS), Italy. E-mail: mzecchin@ogs.trieste.it
MASSIMO ZECCHIN (*) & MAURO CAFFAU (*)
Queste bozze, cor rette deb bo no es sere
re sti tuite im med i at a mente alla Se g re te ria
del la Società Geo log i ca Ital i a na
c/o Di par ti men to di Scienze del la Ter ra
Pi az zale Aldo Moro, 5 – 00185 ROMA
CIVITELLI, 2007; COFFEY & READ, 2007). Moreover, the
prediction of sediment dispersal and partitioning, and ultimately
of their stratal architecture and 3D geometry is
more uncertain. The detailed study of mixed systems is
therefore necessary to improve our knowledge of their features
and evolution, and to compare their development
with pure carbonate or siliciclastic systems.
The present study is focused on a late Pleistocene
marine terrace located on the Capo Colonna promontory
near Crotone, in southern Italy, along the eastern (Ionian)
coast of Calabria (figs. 1A and 1B). This deposit consists
of either shallow-marine sandstones interfingering with
calcarenites and carbonate bioconstructions or mixed
carbonate-siliciclastic sand-sized facies. Quality of outcrops
allows the analysis of facies and stratal characteri -
stics along depositional dip. Such a deposit is therefore
ideal to study facies partitioning in a mixed carbonatesiliciclastic
system.
ZECCHIN et alii (2009) briefly illustrated the main
facies characteristics of the Capo Colonna terrace de -
posits, and in particular made a detailed sequence-stratigraphic
analysis. The present paper, instead, is aimed to a
facies architectural analysis and to discuss the dia gnostic
features of mixed carbonate-siliciclastic systems.
GEOLOGICAL SETTING
The study area is located on the Ionian side of the
Calabrian Arc (southern Italy), where the sedimentary
succession of the Crotone Basin covers deformed rocks of
the same Arc. The Calabrian Arc is a composite terrane
mostly composed of pre-Mesozoic crystalline rocks, located
between the NW-trending southern Apennines and the
E-trending Sicilian Maghrebides. The Arc migrated southeastward
from mid-Miocene onwards in response of the
subduction of the Ionian crust, which generated the backarc
Tyrrhenian basin (MALINVERNO & RYAN, 1986; VAN
DIJK & SCHEEPERS, 1995; BONARDI et alii, 2001). The
south-eastward drift of the Arc was accompanied by pervasive
strike-slip deformation accommodated along se -
veral shear zones, which were characterized by left-lateral
movements in the central and northern parts, and rightlateral
movements in the south (KNOTT & TURCO, 1991).
The Crotone Basin (fig. 1A) is interpreted as a forearc
basin located on the internal part of the Calabrian accretionary
wedge, and its opening started between Serravallian
and Tortonian time (VAN DIJK, 1991; BONARDI et alii,
2001; ZECCHIN et alii, 2004a). The evolution of the basin

was characterized by a dominant extensional tectonic
regime, periodically interrupted by short compressional
or transpressional phases (VAN DIJK, 1991; MASSARI et
alii, 2002; ZECCHIN et alii, 2004a).
Since mid-Pleistocene time, the Calabrian Arc expe -
rienced strong uplift, and a staircase of marine terraces
developed (figs. 1A and 1B). The uplift was interpreted as
the result of either an isostatic rebound that followed the
breaking of the subducted Ionian Crust (SPAKMAN, 1986;
WESTAWAY, 1993; WORTEL & SPAKMAN, 2000), or a convective
removal of the deep root and a consequent decoupling
of the Calabrian Arc from the subducting plate
(DOGLIONI, 1991; GVIRTZMAN & NUR, 2001).
In the study area, marine terraces consist of a transgressive
erosional surface onto a Plio-Pleistocene slope
succession (the Cutro Clay), unconformably overlain by
shallow-marine sediments (GLIOZZI, 1987; PALMENTOLA
et alii, 1990; ZECCHIN et alii, 2004b; ZECCHIN et alii, 2010)
(fig. 1B). ZECCHIN et alii (2004b) identified five levels of
terraces in the Crotone area. The oldest and highest terrace,
named Cutro terrace, is up to ca. 200 m of elevation,
and it has been ascribed to marine isotope stage (MIS) 7
(ca. 200 kyr) (GLIOZZI, 1987; ZECCHIN et alii, 2004b;
NALIN et alii, 2007; ZECCHIN et alii, 2011) or 9 (ca. 330
kyr) (PALMENTOLA et alii, 1990). The younger terraces are
placed between 100 and 8 m, and their estimated ages
range from 125 to 50 kyr B.P. (ZECCHIN et alii, 2004b).
The uplift rate calculated for the Crotone area varies
between 0.4 and 1.8 m/kyr (COSENTINO et alii, 1989; PAL-
MENTOLA et alii, 1990; ZECCHIN et alii, 2004b).
INTRODUCTION
KEY FEATURES OF MIXED CARBONATE-SILICICLASTIC SHALLOW-MARINE SYSTEMS 371
Fig. 1 - A) Geologic sketch-map of the Crotone Basin with location of the Capo Colonna area, SE of Crotone (modified from MASSARI et alii,
2002); B) geologic map of the Capo Colonna promontory, with indication of the ten measured sections (modified from ZECCHIN et alii, 2009).
THE CAPO COLONNA TERRACE
The EW-elongated Capo Colonna promontory is
located a few km south-east of Crotone and extends
toward the Ionian Sea for 3 km, with an eastward dip of
ca. 1 degree (figs. 1A and 1B). The promontory is bordered
by a coastal cliff whose seaward margin is at 10 to
15 m a.s.l. Its landward edge is located at ca. 50 m a.s.l.
and terminates against a steep slope.
The Pleistocene Capo Colonna marine terrace lies on
top of the promontory, and consists of carbonate to siliciclastic
sediments (up to 10 m thick) unconformably overlying
the Plio-Pleistocene deep marine Cutro Clay Formation
(NALIN & MASSARI, 2009; ZECCHIN et alii, 2009) (fig. 1B).
Although all authors consider the terrace younger than
MIS 5e, there is no agreement in its precise age. In particular,
most of the terrace has been ascribed to MIS 5c (about
100 kyr B.P.) by PALMENTOLA et alii (1990) and ZECCHIN et
alii (2009), whereas GLIOZZI (1987) and NALIN & MASSARI
(2009) ascribed the terrace to MIS 5a (about 80 kyr B.P.).
STRATIGRAPHIC ARCHITECTURE
The Capo Colonna terrace is composed of two transgressive-regressive
cycles, 1 to 8m m thick, stacked to
form a retrograding pattern (fig. 2), which is inferred to
be the result of a generalized glacio-eustatic rise superimposed
on regional uplift (NALIN & MASSARI, 2009;
ZECCHIN et alii, 2009). The present study is focused on
the second cycle (CC2, figs. 2-4), that is that better deve -
loped and exposed, allowing an accurate analysis of
downdip facies changes.
A complete analysis of the stratal architecture of
cycles forming the Capo Colonna terrace was provided by
ZECCHIN et alii (2009). The basal surface of both cycles is
represented by a wave ravinement surface (WRS) cutting
into the Plio-Pleistocene Cutro Clay, and overlain by
coarse-grained lags and transgressive shell concentrations
(ZECCHIN et alii, 2009) (figs. 2-4). The WRS that marks
the base of the CC2 cycle may be picked for ca. 3 km
downdip (fig. 2) and has an average seaward gradient of
ca. 0.6°. The dip of the surface is thought to be close to

372 M. ZECCHIN & M. CAFFAU
Fig. 2 - Dip-oriented cross-section along the northern side of the Capo Colonna promontory (see fig. 1B for location of the sections).
The transgressive-regressive CC2 cycle is the subject of the present study (modified from ZECCHIN et alii, 2010).
Fig. 3 - Measured sections of the northern transect (see fig. 1B for location and fig. 4 for symbols). The transect represents the beachface to
shelf deposits forming the CC2 cycle of the Capo Colonna terrace. Distal settings are toward the right.

KEY FEATURES OF MIXED CARBONATE-SILICICLASTIC SHALLOW-MARINE SYSTEMS 373
Fig. 4 - The two sections measured along the southern side of the Capo Colonna promontory (see fig. 1B for location). These shelf deposits
sharply overlie the Cutro Clay, which represents the substrate of the marine terrace.
that original, indicating that the terrace has not been
tilted. Such a WRS is associated to a Glossifungites ichnofacies
where it truncates the upper part of the CC1 cycle
(ZECCHIN et alii, 2009) (fig. 3). Regressive clastic shoreface
deposits pass distally into mostly coralline algal frameworks
and associated calcarenites (NALIN & MASSARI,
2009; ZECCHIN et alii, 2009) (figs. 2-4). The general stratigraphic
architecture of both cycles highlights relatively
thin transgressive and thick regressive intervals (fig. 2).
The latter can be top-truncated due to wave ravinement
during a subsequent erosional transgression.
FACIES ANALYSIS OF THE CC2 CYCLE
The CC2 cycle is composed of three facies associations
composing a shoreface-shelf depositional system.
According to the sequence stratigraphic interpretation by
ZECCHIN et alii (2009), the sharp surface that marks the
base of the cycle, interpreted as a wave-scoured ravine-
ment surface and paved by the deposits of facies association
A, erodes both the substrate of the terrace (the Cutro
Clay) and the upper shoreface deposits forming part of
the CC1 cycle (figs. 2 and 3). The boundary between the
facies associations A (below) and B-C (above) is interpreted
as the boundary between transgressive deposits
accumulated during siliciclastic starvation (facies association
A) and normal plus forced regressive deposits, i.e. a
maximum flooding surface (figs. 2 and 3). The boundary
between normal and forced regressive deposits is thought
to coincide with the erosional contact between Facies B1
(below) and shallower clastic deposits of Facies C1
(above), that is found in distal locations (figs. 2 and 3).
BASAL CONDENSED DEPOSITS (FACIES ASSOCIATION A) - TST
Basal conglomerate (Facies A1)
This facies is locally present at the base of the terrace
deposits (Col 10 section, fig. 4), and consists of a granule-

374 M. ZECCHIN & M. CAFFAU
Fig. 5 - Well cemented shell bed (Facies A2) and bryozoan-bearing
calcirudite (Facies A3), which form the rigid substrate of the coralline
algal frameworks of Facies B1. The outcrop is located close to the
Col 3 section (see fig. 1B for location).
to cobble-size (up to 10 cm) conglomerate up to 10 cm
thick. Clasts are well rounded and commonly elongated,
and are composed of quartz and lithic fragments. The
matrix consists of fine-grained quartz sandstone. The
base of the facies is highly erosional and locally irregular
at the outcrop scale, and corresponds to the sharp contact
between the substrate (the Cutro Clay) and the terrace
deposits (fig. 10).
Shell bed (conquina) (Facies A2)
Facies A2 (up to 40 cm thick) displays a lenticular
shape in dip sections, thinning toward both onshore
and offshore (fig. 3). It consists of a cemented and burrowed
calcirudite made of pectinid and oyster fragments,
with minor bryozoans (figs. 3-5). A mixed siliciclastic-carbonate
fraction, consisting of medium- to
coarse-grained sandstone, is present. The deposit is
structureless to flat-laminated, and its base is flat and
erosional. Facies A2 lies in the lower part of the CC2
cycle, above Facies A1 or directly at the contact with the
underlying CC1 cycle, and is abruptly overlain by Facies
A3 or Facies B1 (figs. 3-5).
Bryozoan-bearing calcirudite (Facies A3)
As observed in Facies A2, also Facies A3 displays a
lenticular shape that thins both offshore and onshore
(the Col 3 section, fig. 3). Facies A3 (up to 50 cm thick)
consists of a highly packed bryozoan-bearing calcirudite
with a minor amount of pectinid shell fragments and
quartz granules (figs. 3 and 5). The facies is locally cha -
racterized by an unidirectional cross-stratification partially
masked because of the coarse grain size (fig. 3).
Sets are 20 cm thick, and foreset are 10° to 15° inclined.
The base is sharp and erosional, whereas the top consists
of a non-erosional contact with Facies B1 (figs. 3
and 5).
A term intermediate between Facies A2 and A3 is present
in the Col 5 section (fig. 3). Here, a planar-stratified
and locally burrowed calcirudite composed of mixed
oyster valves and bryozoans is visible at the base of the
terrace deposits. Fragments of calcareous algae are mixed
with bryozoans in the upper part of the facies (fig. 3).
This deposit is overlain by Facies B1 and B2 (fig. 3).
Interpretation of facies association A
The conglomerate of Facies A1, found at the base of
the terrace deposits, is interpreted as a transgressive lag
deposit accumulated after wave erosion and reworking of
clasts from the substrate (DEMAREST & KRAFT, 1987;
NUMMEDAL & SWIFT, 1987; KIDWELL, 1991). Deposits of
Facies A2 and A3 record a phase of generalized silicicla -
stic sediment bypass and starvation promoting the concentration
of skeletal material in distal shoreface to shelf
settings (e.g. KIDWELL, 1991; NAISH & KAMP, 1997).
Moreover, Facies A3 resulted from the colonization of
a stable substrate by epifaunal benthic communities
(KONDO et alii, 1998), then transported by shelf currents
to form cross bedding. Facies A2 and A3, therefore,
formed an extensive carbonate pavement in relatively
distal settings, which was subjected to early cementation
providing a rigid substrate for the growth of the coralline
algal frameworks of Facies B1.
CORALLINE ALGAL FRAMEWORK AND ASSOCIATED DE -
POSITS (FACIES ASSOCIATION B) - HST
Coralline algal framework (Facies B1)
This facies is well represented in the middle to outer
part of the measured transect, where it is at least 3.5 m
thick (the Col 4 section), and thins both offshore and
onshore (fig. 3). Moreover, the facies shows a patchy di -
stribution in landward locations, where abrupt lateral
contacts with clastic deposits are recognizable (Col 5 and
Col 10 sections, figs. 2-4). Facies B1 consists of a laterally
extensive carbonate body that commonly form well
cemented frameworks (figs. 3-7). The primary framework
builders are coralline algae that form a compact structure,
whereas bryozoans, corals (Cladocora caespitosa),
serpulid-worm tubes, mollusc shells (pectinids, oysters
and gastropods) and fragments of echinoids represent
accessory components (figs. 3, 4, 6A, 6B and 8). Although
the encrusting succession is unclear, four species were
identified in the algal assemblages in variable proportion:
Titanoderma pustulatum (Lamouroux), Mesophyllum
alternans (Foslie) CABIOCH & MENDOZA, and minor Lithophyllum
incrustans Philippi and Spongites sp. (fig. 8).
Locally, the framework is less massive and contains
also a siliciclastic fraction, consisting of quartz sandstone
to granule clasts (Col 2 and Col 10 sections, figs. 3 and 4).
Irregular cavities, filled by sediments of Facies B2 (see
below), are very common (figs. 3, 4 and 7). Near its landward
termination, Facies B1 consists of large patches,
some tens of meters wide, laterally confined by sediments
of Facies B2 (see below) (figs. 2, 3 and 6D). The coralline
algal framework typically lie upon the pavement formed
by Facies A2 and A3, which offered a rigid substrate for
the growth of the bioconstructions (figs. 2-5).
Calcarenites and calcirudites (Facies B2)
Facies B2 consists of well cemented bioclastic
deposits filling irregular cavities into the coralline algal
frameworks of Facies B1, or accumulated adjacent to
them (figs. 2, 3, 4, 6A, 6C, 6D and 7). The bioclastic detritus
is mostly composed of mollusc shells, bryozoans and

Fig. 6 - Coralline algal frameworks
and associated deposits: A) detail of
the framework of Facies B1 near the
Col 3 section, showing calcareous
algae, bryozoans and minor calcarenite
of Facies B2; B) detail of the
algal laminae of Facies B1 (Col 4
section); C) sharp contact between
coralline algal frameworks (Facies
B1) and the calcarenites of Facies
B2 at the Col 4 section; D) sharp lateral
contact between stratified calcarenites
(Facies B2) and coralline
algal frameworks (Facies B1) at the
Col 5 section.
KEY FEATURES OF MIXED CARBONATE-SILICICLASTIC SHALLOW-MARINE SYSTEMS 375
coralline algal fragments. A siliciclastic component, consisting
of very coarse-grained sandstone to granule-size
micro-conglomerate, is present with variable amount.
Cavities affecting Facies B1 have commonly a vertical
development, reaching up to 2.5 m of height (the Col 4
section, fig. 3); their fill is typically structureless, and the
bioturbation is common (fig. 7). Calcarenites and calcirudites
laterally juxtaposed to the patches of Facies B1 have
a thickness similar to that of the algal frameworks themselves
(figs. 3 and 6D), whereas their lateral extent is
more difficult to evaluate, and is estimated in the order of
tens of metres. The contact with Facies B1 may be vertical,
and is very sharp and locally clearly erosional (figs. 3
and 6D). These deposits show a well developed flat to
inclined and undulate lamination and locally trough
cross-stratification (figs. 3 and 6D). Internal, irregular
erosional surfaces truncating the underlying laminae are
very common. Burrow traces are present.
Interpretation of facies association B
This facies association records optimum conditions for
the carbonate factory, that consisted in the growth of
coralline algal frameworks (Facies B1) upon the rigid substrate
provided by the skeletal accumulations of facies
association A. The optimal depth for coralline algal framework
growth in the present day Mediterranean ranges
between 30 and 60 m (LABOREL, 1961; PÉRÈS & PICARD,
1964; BOSENCE, 1983). The thinning of Facies B1 both in
seaward and landward directions, as well as its patchy di -
stribution in relatively proximal settings, are inferred to be
due to environmental conditions away from the optimum
for coralline algal growth. The mollusc shells, the echinoids
and the coarse siliciclastic fraction recognized
within Facies B1 are inferred to have deposited after major
Fig. 7 - Calcarenites of Facies B2 filling a cavity within the coralline
algal framework of Facies B1 at the Col 4 section.

376 M. ZECCHIN & M. CAFFAU
Fig. 8 - Thin sections of coralline algal frameworks (Facies B1): A) conceptacles of Titanoderma pustulatum (Lamouroux); B) Lithophyllum
incrustans Philippi. Note the horizontal alignment of uniporate conceptacles. Serpulid-worm tubes are present above.
Fig. 9 - Clastic deposits of the facies association C: A) sharp contact between the lower shoreface siliciclastic sandstones of Facies C1 and the upper
shoreface sandstones of Facies C2 near the Col 6 section. Trough-cross sets are highlighted on the left; B) sharp lateral contact between the siliciclastic
Facies C1 and the coralline algal framework of Facies B1 at the Col 10 section. Large coralline algal fragments are present in Facies C1.
storms transporting sediment seawards. Facies B2 represents
bioclastic accumulations associated to Facies B1, in
part composed of coralline algal detritus. The recognized
sedimentary structures in Facies B2 are interpreted to have
been produced by both unidirectional flows, possibly
storm driven, and oscillatory flows affecting proximal shelf
settings during major storms. Lateral confinement among
the patches of Facies B1 landwards enhanced bottom currents
that were able to erode the walls of the rigid coralline
algal frameworks and to transport coarse sediment.
SILICICLASTIC TO BIOCLASTIC DEPOSITS (FACIES ASSOCIA-
TION C) - HST+FRST
Siliciclastic to bioclastic laminated sandstone (Facies C1)
This facies is recognizable both in distal and proximal
sections, and consists of very fine- to medium-
grained siliciclastic sandstone to mixed siliciclasticbioclastic,
locally well cemented sandstone (figs. 3, 4
and 9). The bioclastic component mostly consists of
mollusc shells, bryozoans and coralline algal fragments,
and its abundance varies significantly, reaching
a minimum in the siliciclastic intervals. The thickness
of the facies varies from a few dm to 3.5 m (figs. 3
and 4). Sedimentary structures are represented by flat
lamination and low angle cross-stratification, and the
bioturbation is present but not pervasive (figs. 3, 4 and 9).
The base of Facies C1 is commonly erosional on the
coralline algal frameworks (Facies B1) or on the basement
(figs. 3 and 4). Mostly siliciclastic sandstones of
Facies C1 passes into Facies C2 landwards (figs. 2 and 3),
and are laterally juxtaposed to Facies B1 in the Col 10
section (figs. 4 and 9B). Facies C1 may occasionally
lie below Facies B1 (the Col 3 section, fig. 3), forming
dm-thick lenses.

Fig. 10 - Cartoon showing the Capo
Colonna depositional system during
co ralline algal framework growth. The
system is characterized by siliciclastic
sedimentation in proximal settings passing
into mostly carbonate sedimentation
seawards. Currents locally washedout
the calcarenites associated to the
coralline algal frameworks, and sili -
ciclastic sandstones may be laterally
juxtaposed to the latter. Transgressive
strata are represented by the condensed
deposits of the facies association A,
whereas the bulk of the sedimentation
occurred during highstand conditions.
KEY FEATURES OF MIXED CARBONATE-SILICICLASTIC SHALLOW-MARINE SYSTEMS 377
Trough cross-bedded sandstone (Facies C2)
This facies is present in the proximal sections, where
its lower contact locally corresponds with the base of the
terrace deposits (the Col 7 section, figs. 2 and 3), and its
thickness reaches 3 m. The facies passes into Facies C1 in
a seaward direction, locally with a sharp contact, and it is
overlain by a fine-grained wedge derived from palaeocoastal
cliff dismantling in subaerial conditions (figs. 2, 3
and 9A). Facies C2 consists of trough-cross stratified,
medium- to very coarse-grained, mixed siliciclastic to bioclastic
sandstone (figs. 3 and 9A). Cross sets commonly
alternate with planar-laminated intervals (figs. 3 and 9A).
Bioclastic layers are well cemented. Pectinid shells and
burrows are occasionally present. Trough cross-sets are
up to 30 cm thick and foreset laminae are inclined
between 15° and 40°.
Toe of cliff deposit (Facies C3)
This facies is present only in the extreme proximal
part of the transect, at its landward termination (the Col 8
section, figs. 2 and 3), and consists of cobble to boulder
size (10 cm to 1 m) calcareous clasts. Cobbles and boulders
are commonly bored by Lithophaga holes, and are
associated with medium- to coarse-grained quartz sandstone,
which becomes dominant seaward and shows flat
to very low-angle lamination (fig. 3). Facies C3 passes seaward
into Facies C2 (fig. 3).
Interpretation of facies association C
This facies association is representative of a mixed
siliciclastic-bioclastic shoreface-shelf system, receiving
the supply of both terrigenous and intrabasinal bioclastic
detritus.
The structures and distribution of Facies C1 suggest
the accumulation in relatively lower energy condition in
distal shoreface to inner shelf settings (READING &
COLLINSON, 1996; CLIFTON, 2006). The facies replaces the
coralline algal frameworks (Facies B1) in proximal settings,
whereas its lower erosional contact above Facies B1
indicates an accumulation in more distal settings when
algal growth ceased. The local lateral contact of Facies C1
with Facies B1 suggests the action of strong currents
among the coralline algal framework patches, which were
able to turn away the calcarenites (Facies B2) associated
to Facies B1 and then mostly siliciclastic fine-grained
sediment was deposited during calmer conditions.
The trough cross-bedded Facies C2, located in more
proximal settings, represents an upper shoreface deposit,
where 3D dunes migrated in the surf zone due to the
action of longshore and rip currents (MASSARI & PAREA,
1988; HART & PLINT, 1995; CLIFTON, 2006). The locally
recognized sharp lower contact with Facies C2 is interpreted
as the surf diastem (ZHANG et alii, 1997), bounding
the upper shoreface zone and migrating seawards during
coastal regression (CLIFTON, 2006).
Facies C3 derives from the accumulation of coarse
detritus coming from older marine terraces located on top
of the partially eroded palaeo-coastal cliff that lies just
behind the Capo Colonna terrace. This deposit, passing
seaward into Facies C2, is inferred to have accumulated in
a beachface context (e.g. POMAR & TROPEANO, 2001).
DISCUSSION
Present data highlight that facies associations reco -
gnized in the CC2 cycle of the Capo Colonna terrace
deposits form a mixed carbonate-siliciclastic system,
showing shelf condensed deposits (facies association A)
overlain by coralline algal frameworks and related calcarenites
(facies association B), that pass landwards and
upwards into shoreface-shelf clastic deposits (facies association
C) (figs. 2 and 10).
Current models of carbonate ramp sedimentation and
architecture highlight the role of the interplay between
accommodation creation and carbonate production/rate
of reef growth in determining the slope and morphology
of the ramp itself (WILSON, 1975; JAMES & CLARKE, 1997;
WRIGHT & BURCHETTE, 1998; POMAR, 2001a,b; PEDLEY &
CARANNANTE, 2006). Non-tropical carbonates are commonly
characterized by a land-attached clastic wedge, an
increase of bryozoans with depth, and by dominant
coralline algal deposits in mid-ramp settings (CARAN-
NANTE et alii, 1988; MARTÍN et alii, 1996, 2004; PEDLEY &
GRASSO, 2002).
NALIN & MASSARI (2009) considered the CC2 cycle as
an example of non-tropical carbonate ramp deposit. They
also noted that the asymmetric architecture of the CC2
cycle, consisting of thicker regressive deposits, shows

378 M. ZECCHIN & M. CAFFAU
closer affinities with siliciclastic systems (see ZECCHIN,
2007) than non-tropical carbonate systems, as the latter
commonly feature limited inner shelf deposition (RYAN
et alii, 2008). NALIN & MASSARI (2009) explained this
discrepancy as the consequence of minor hydrodynamic
levels during accumulation of the Capo Colonna deposits
with respect to other contexts.
In the Capo Colonna deposits, an important silicicla -
stic component, becoming dominant landwards, characterizes
the system, and this must be considered to justify
the observed stratal architecture of the CC2 cycle. Due to
the action of waves and shelf currents, clean siliciclastic
fine-grained sandstones of Facies C1 could be transported
offshore and accumulated adjacent to coralline algal
frameworks (fig. 9B). Moreover, also coarser siliciclastic
particles were transported offshore during storms, composing
a minor fraction of mostly carbonate deposits.
Thus, the dominance of mixed clastic sedimentation in
proximal settings justifies the strong resemblance of the
architecture of the considered cycle with that of silicicla -
stic systems, which are typically characterized by the
R cycle architecture (i.e. dominated by the regressive
component of the cycle; ZECCHIN, 2007) in sequences
controlled by late Quaternary glacio-eustasy (ZECCHIN et
alii, 2009; ZECCHIN et alii, 2010). It should also be noted
that the deposits of the Capo Colonna terrace overlie a
fine-grained terrigenous unit, and that the overall dip of
the shoreface and shelf during deposition was inherited
from the dip of the basal WRS (fig. 2), not controlled by
carbonate productivity. The geometry of the WRS is in
turn controlled by wave energy during transgression, rate
of relative sea-level rise, sediment supply and inherited
physiography (CATTANEO & STEEL, 2003; ZECCHIN, 2007).
Taking into account the present evidence, therefore,
in contrast to NALIN & MASSARI (2009) it is highlighted
that the CC2 cycle of the Capo Colonna terrace cannot be
considered as a carbonate ramp deposit, and it should
be referred to a temperate mixed carbonate-siliciclastic
shallow-marine depositional system. The main features of
this mixed system include (figs. 2 and 10): dominance of
coralline algal deposition in distal settings; mixed siliciclastic-bioclastic
sedimentation in proximal settings; pe -
culiar lateral juxtapositions between siliciclastic deposits
and coralline algal frameworks due to hydrodynamic
processes; comparability of the stratal architecture of the
clastic-dominated part of the system to that of siliciclastic
shelf/ramp systems. Moreover, it is important to note that
the gradient of the studied shoreface-shelf system is not
controlled by carbonate productivity but is inherited by
the processes acting before and during transgression.
CONCLUSIONS
Facies and architectural analyses of the CC2 cycle,
forming most part of the Capo Colonna terrace deposits,
show a mix of carbonate and siliciclastic sediments accumulated
in a shoreface-shelf setting. Key diagnostic features
of these mixed deposits are (i) the prevalence of
clastic deposits landwards and coralline algal frameworks
seawards, (ii) a stratal architecture comparable to that of
siliciclastic systems, that is the dominance of regressive
deposits in late Quaternary sequences, (iii) the dominant
role of the inherited physiography and processes typifying
the transgression rather than carbonate productivity in
shaping the shelf profile, and (iv) the local lateral juxtaposition
of siliciclastic sandstones and coralline algal frameworks
in shelf settings due to hydrodynamic processes.
ACKNOWLEDGMENTS
This study was carried out within the CARG Project (official
geological cartography of Italy, scale 1:50,000) for the geological
mapping of the Ionian Calabria. Reviews by Marcello Tropeano and
Marco Brandano significantly improved the paper.
REFERENCES
BETZLER C., BRACHERT T.C., BRAGA J.C. & MARTÍN J.M. (1997) -
Nearshore, temperate, carbonate depositional systems (lower Tortonian,
Agua Amarga Basin, southern Spain): implications for
carbonate sequence stratigraphy. Sed. Geol., 113, 27-53.
BONARDI G., CAVAZZA W., PERRONE V. & ROSSI S. (2001) - Calabria-
Peloritani terrane and northern Ionian Sea. In: Vai G.B. & Mar -
tini I.P. (Eds.), Anatomy of an Orogen: The Apennines and
Adjacent Mediterranean Basins. Kluwer Academic Publishers,
Bodmin, 287-306.
BOSENCE D.W.J. (1983) - Coralline algal reef frameworks. J. Geol.
Soc. London, 140, 365-376.
BRANDANO M. & CIVITELLI G. (2007) - Non-seagrass meadow sedimentary
facies of the Pontinian Islands, Tyrrhenian Sea: a modern
example of mixed carbonate-siliciclastic sedimentation. Sed.
Geol., 201, 286-301.
CARANNANTE G., ESTEBAN M., MILLIMAN J.D. & SIMONE L. (1988) -
Carbonate lithofacies as paleolatitude indicators: problems and
limitations. Sed. Geol., 60, 333-346.
CATTANEO A. & STEEL R.J. (2003) - Transgressive deposits: a review of
their variability. Earth-Sci. Rev., 62, 187-228.
CLIFTON H.E. (2006) - A reexamination of facies models for clastic
shorelines. In: Posamentier H.W. & Walker R.G. (Eds.), Facies
Models Revisited. SEPM, Spec. Publ., 84, 293-337.
COFFEY B.P. & READ J.F. (2007) - Subtropical to temperate facies
from a transition zone, mixed carbonate-siliciclastic system,
Palaeogene, North Carolina, USA. Sedimentology, 54, 339-365.
COSENTINO D., GLIOZZI E. & SALVINI F. (1989) - Brittle deformations
in the Upper Pleistocene deposits of the Crotone Peninsula, Calabria,
southern Italy. Tectonophysics, 163, 205-217.
DEMAREST J.M. & KRAFT J.C. (1987) - Stratigraphic record of Quaternary
sea levels: implications for more ancient strata. In: Nummedal
D., Pilkey O.H. & Howard J.D. (Eds.), Sea-Level Fluctuation
and Coastal Evolution. SEPM, Spec. Publ., 41, 223-239.
DOGLIONI C. (1991) - A proposal of kinematic modelling for W-dipping
subductions. Possible applications to the Tyrrhenian-Apennines
system. Terra Nova, 3, 423-434.
GLIOZZI E. (1987) - I terrazzi del Pleistocene superiore della penisola di
Crotone (Calabria). Geol. Romana, 26, 17-79.
GVIRTZMAN Z. & NUR A. (2001) - Residual topography, lithospheric
structure and sunken slabs in the central Mediterranean. Earth
Planet. Sci. Lett., 187, 117-130.
HART B.S. & PLINT A.G. (1995) - Gravelly shoreface and beachface
deposits. In: Plint A.G. (Ed.), Sedimentary Facies Analysis. Int.
Ass. Sedim., Spec. Publ., 22, 75-99.
JAMES N.P. & CLARKE J.A.D. (Eds.) (1997) - Cool-water carbonates.
SEPM, Spec. Publ., 56, 1-440.
KIDWELL S.M. (1991) - Condensed deposits in siliciclastic sequences:
expected and observed features. In: Einsele G., Ricken W. & Seilacher
A. (Eds.), Cycles and Events in Stratigraphy. Springer-
Verlag, Berlin, 682-695.
KNOTT S.D. & TURCO E. (1991) - Late Cenozoic kinematics of the
Calabrian Arc, southern Italy. Tectonics, 10, 1164-1172.
KONDO Y., ABBOTT S.T., KITAMURA A., KAMP P.J.J., NAISH T.R., KA-
MATAKI T. & SAUL G.S. (1998) - The relationship between shellbed
type and sequence architecture: examples from Japan and New
Zealand. Sed. Geol., 122, 109-127.
LABOREL J. (1961) - Le Concretionnement algal “coralligene” et son
importance geomorphologique en Mediterranée. Stat. Mar. End.
Rec. Trav., 23, 37-60.

KEY FEATURES OF MIXED CARBONATE-SILICICLASTIC SHALLOW-MARINE SYSTEMS 379
MALINVERNO A. & RYAN W.B.F. (1986) - Extension in the Tyrrhenian
Sea and shortening in the Apennines as a result of arc migration
driver by sinking of the lithosphere. Tectonics, 5, 227-245.
MARTÍN J.M., BRAGA J.C., BETZLER C. & BRACHERT T. (1996) - Sedimentary
model and high-frequency cyclicity in a Mediterranean,
shallow-shelf, temperate-carbonate environment (uppermost Miocene,
Agua Amarga Basin, Southern Spain). Sedimentology, 43,
263-277.
MARTÍN J.M., BRAGA J.C., AGUIRRE J. & BETZLER C. (2004) - Contrasting
models of temperate carbonate sedimentation in a small
Mediterranean embayment: the Pliocene Carboneras Basin, SE
Spain. J. Geol. Soc. London, 161, 387-399.
MASSARI F. & PAREA G.C. (1988) - Progradational gravel beach
sequences in a moderate- to high-energy, microtidal marine environment.
Sedimentology, 35, 881-913.
MASSARI F., RIO D., SGAVETTI M., PROSSER G., D’ALESSANDRO A.,
ASIOLI A., CAPRARO L., FORNACIARI E. & TATEO F. (2002) -
Interplay between tectonics and glacio-eustasy: Pleistocene succession
of the Crotone basin, Calabria (southern Italy). Geol. Soc.
Am. Bull., 114, 1183-1209.
MOUNT J.F. (1984) - Mixing of siliciclastic and carbonate sediments in
shallow shelf environments. Geology, 12, 432-435.
NAISH T.R. & KAMP P.J.J. (1997) - Sequence stratigraphy of sixthorder
(41 k.y.) Pliocene-Pleistocene cyclothems, Wanganui basin,
New Zealand: A case for the regressive systems tract. Geol. Soc.
Am. Bull., 109, 978-999.
NALIN R., MASSARI F. & ZECCHIN M. (2007) - Superimposed cycles of
composite marine terraces: the example of Cutro terrace (Calabria,
Southern Italy). J. Sed. Res., 77, 340-354.
NALIN R. & MASSARI F. (2009) - Facies and stratigraphic anatomy of
a temperate carbonate sequence (Capo Colonna terrace, Late Pleistocene,
southern Italy). J. Sed. Res., 79, 210-225.
NUMMEDAL D. & SWIFT D.J.P. (1987) - Transgressive stratigraphy at
sequence-bounding unconformities: some principles derived from
Holocene and Cretaceous examples. In: Nummedal D., Pilkey
O.H. & Howard J.D. (Eds.), Sea-Level Fluctuation and Coastal
Evolution. SEPM, Spec. Publ., 41, 241-260.
PALMENTOLA G., CAROBENE L., MASTRONUZZI G. & SANSÒ P. (1990) -
I terrazzi marini Pleistocenici della Penisola di Crotone (Calabria).
Geogr. Fis. Din. Quat., 13, 75-80.
PEDLEY H.M. & CARANNANTE G. (Eds.) (2006) - Cool-water carbonates:
depositional systems and palaeoenvironmental controls. Geol.
Soc., Spec. Publ., 255, 1-384.
PEDLEY H.M. & GRASSO M. (2002) - Lithofacies modeling and sequence
stratigraphy in microtidal cool-water carbonates: a case
study from the Pleistocene of Sicily, Italy. Sedimentology, 49,
533-553.
PÉRÈS J.M. & PICARD J. (1964) - Manuel de Binomie benthique de la
Mer Mèditerranée. Stat. Mar. End. Rec. Trav., 31, 1-137.
POMAR L. (2001a) - Ecological control of sedimentary accommodation:
evolution from a carbonate ramp to a rimmed shelf, upper
Miocene, Balearic Islands. Palaeog., Palaeoclimat., Palaeoecol.,
175, 249-272.
POMAR L. (2001b) - Types of carbonate platforms: a genetic approach.
Basin Res., 13, 313-334.
POMAR L. & KENDALL C.G.S.C. (2008) - Architecture of carbonate
platforms: A response to hydrodynamics and evolving ecology. In:
Lukasik J. & Simo A. (Eds.), Controls on Carbonate Platform
and Reef Development. SEPM, Spec. Publ., 89, 187-216.
POMAR L. & TROPEANO M. (2001) - The Calcarenite di Gravina
Formation in Matera (southern Italy): new insights for coarse-
grained, large-scale, cross-bedded bodies encased in offshore deposits.
AAPG Bull., 85, 661-689.
READING H.G. & COLLINSON J.D. (1996) - Clastic coasts. In: Reading
H.G. (Ed.), Sedimentary Environments; Processes, Facies and
Stratigraphy. Blackwell Science, Oxford, 154-231.
RYAN D.A., BROOKE B.P., COLLINS L.B., SPOONER M.I. & SIWABESSY
P.J.W. (2008) - Formation, morphology and preservation of
high-energy carbonate lithofacies: evolution of the cool-water
Recherche Archipelago inner shelf, south-western Australia. Sed.
Geol., 207, 41-55.
SCHLAGER W. (1991) - Depositional bias and environmental change -
important factors in sequence stratigraphy. Sed., Geol., 70, 109-130.
SCHLAGER W. (1993) - Accommodation and supply - a dual control on
stratigraphic sequences. Sed., Geol., 86, 111-136.
SPAKMAN W. (1986) - Subduction beneath Eurasia in connection with
the Mesozoic Tethys. Geol. Mijnbouw, 65, 145-153.
VAN DIJK J.P. (1991) - Basin dynamics and sequence stratigraphy in
the Calabrian Arc (Central Mediterranean): Records and pathways
of the Crotone Basin. Geol. Mijnbouw, 70, 187-201.
VAN DIJK J.P. & SCHEEPERS P.J.J. (1995) - Neotectonic rotations in
the Calabrian Arc; implications for a Pliocene-Recent geodynamic
scenario for the Central Mediterranean. Earth-Sci. Rev., 39,
207-246.
WESTAWAY R. (1993) - Quaternary uplift of Southern Italy. J. Geophys.
Res., 98, 21741-21772.
WILSON J.L. (1975) - Carbonate Facies in Geologic History. Springer-
Verlag, New York, 1-471.
WORTEL M.J.R. & SPAKMAN W. (2000) - Subduction and slab detachment
in the Mediterranean-Carpathian region. Science, 290, 1910-
1917.
WRIGTH V.P. & BURCHETTE T.P. (1998) - Carbonate ramps: an introduction.
In: Wright V.P. & Burchette T.P. (Eds.), Carbonate
Ramps. Geol. Soc., Spec. Publ., 149, 1-5.
ZECCHIN M. (2007) - The architectural variability of small-scale cycles
in shelf and ramp clastic systems: the controlling factors. Earth-
Sci. Rev., 84, 21-55.
ZECCHIN M., CAFFAU M., TOSI L., CIVILE D., BRANCOLINI G., RIZZET-
TO F. & RODA C. (2010) - The impact of Late Quaternary glacioeustasy
and tectonics on sequence development: Evidence from
both uplifting and subsiding settings in Italy. Terra Nova, 22,
324-329.
ZECCHIN M., CIVILE D., CAFFAU M. & RODA C. (2009) - Facies and cycle
architecture of a Pleistocene marine terrace (Crotone, southern
Italy): A sedimentary response to late Quaternary, high-frequency
glacio-eustatic changes. Sed. Geol., 216, 138-157.
ZECCHIN M., CIVILE D., CAFFAU M., STURIALE G. & RODA C. (2011) -
Sequence stratigraphy in the context of rapid regional uplift and
high-amplitude glacio-eustatic changes: the Pleistocene Cutro
Terrace (Calabria, southern Italy). Sedimentology, 58, 442-477.
ZECCHIN M., MASSARI F., MELLERE D. & PROSSER G. (2004a) - Anatomy
and evolution of a Mediterranean-type fault bounded basin:
The Lower Pliocene of the northern Crotone Basin (Southern
Italy). Basin Res., 16, 117-143.
ZECCHIN M., NALIN R. & RODA C. (2004b) - Raised Pleistocene marine
terraces of the Crotone peninsula (Calabria, southern Italy):
Facies analysis and organization of their deposits. Sed. Geol.,
172, 165-185.
ZHANG Y., SWIFT D.J.P., NIEDORODA A.W., REID C.W. & THORNE
J.A. (1997) - Simulation of sedimentary facies on the northern
California shelf: implications for an analytical theory of facies
differentiation. Geology, 27, 635-638.
Manuscript received 11 February 2011; accepted 17 June 2011; editorial responsability and handling by W. Cavazza.