Thesis_MSc_Ruben_A

A Compressional Sedimentary Basin on top of
the Calabrian Subduction Zone
Ruben Arismendy, Andrea Forzoni, Ingeborg Kraaij
Vrije Universiteit Amsterdam
Abstract
Previous studies have portrayed the Crati basin as an extensional basin bound by N-S
striking normal faults, either as a graben or half-graben (Tortorici et al., 1995; Cifelli
et al., 2007). In this paper we present renewed insights on the evolution of the basin.
A combination of structural-kinematical field study and interpretations of onshore
seismic lines resulted in a 3D model for the basin in which shortening plays a
previously unrecognized role.
During the Upper Miocene an extensional tectonic regime induced generalized
subsidence with the accommodation space being filled by transgressive clastic
deposits. The Crati basin was still connected with the Paola basin in the west while, in
the east, the Sila Massif was already an important relief.
An E-W compressional regime controlled the evolution of the basin during Pliocene-
Quaternary times, possibly since the Messinian.
Transgressive marine Pliocene deposits were initially accumulated on a pre-existing
topography, likely formed due to the Messinian sea level fall. Due to generalized
subsidence the basin became wider and water depth increased through time. Thrusting
in both flanks of the basin resulted in the relative uplift of the Coastal Range in the
west and of the Sila Massif in the east with respect to the basin centre. During the
Pleistocene folding and thrusting affected only the western part of the basin
meanwhile fan-deltas deposits gradually filled in the basin. From the Middle
Pleistocene to present a large wavelength regional uplift affected the whole area,
which resulted in the dissection and in the terracing of the Crati Basin deposits. The
Coastal Range experienced higher rates of uplift due to the ongoing activity of folds
and east-verging thrusts.
All results were assembled within a regional profile across the Calabrian Arc in order
to show the relations with the Paola basin in the west and with the Crotone basin in
the east and to describe the regional geological evolution through time.

2
1. Introduction
The Calabrian arc is a prominent arc-
shaped structure of the Mediterranean
orogenic belt. It forms the connection
between the Maghrebian chain in the
south and the southern Apennines
chain in the north (Figure1). The arc
structure is the result of thrusting and
nappe stacking, related to the
subduction process involving the
European-African margin during the
Neogene (Van Dijk et al., 2000; Tansi
et al., 2007).
The subduction system progressively
migrated to SE, due to the roll-back of
the NW dipping Ionian slab
(Malinverno and Ryan, 1986;
Faccenna et al., 2002; Cifelli et al.,
2007). This migration led first to the
opening of the Algero-Provencal basin
during the Oligocene-Middle Miocene
and secondly of the Tyrrhenian basin
during the Upper Miocene-Quaternary.
The latter is usually interpreted as a
back-arc basin (Faccenna et al., 2001).
The deep structure of the Calabrian
subduction zone has been extensively
studied: tomographic images and
earthquakes distribution evidence a
narrow and steep slab below southern
and central Calabria which has broken
off below northern Calabria-Apennines
and below Sicily-Maghrebides
(Chiarabba et al., 2007; Neri et al.,
2009). Furthermore numerous recent
studies focused on the modelling of
mantle circulation around the Ionian
slab under Calabria (Civello et al.,
2004; Funiciello et al., 2004;
Faccenna et al., 2001).
Although much is known about the
deep structure of the arc, its shallow
architecture and its superficial tectonic
regime are less constrained.
In its very recent geological history
(Middle Pleistocene to present) the
Calabrian arc experienced a marked
uplift, which is spectacularly
documented by a flight of coastal
terraces displaced to hundreds of
meters above the present sea-level
(Bordoni and Valensise, 1998;
Westaway 2007; Zecchin et al., 2004;
Ferranti et al., 2009).
Figure 1: Regional structures
Extension, induced by the Miocene to
Quaternary opening of the Tyrrhenian
back-arc basin, is generally considered
the main mechanism for the
exhumation of high pressure
metamorphic rocks in onshore Calabria
and for the uplift of the major
mountain ranges (Thomson, 1994;
Rossetti et al., 2004). Furthermore
extension is thought to be controlling
the formation of sedimentary basins in
the area since the Upper Miocene
(Mattei et al., 2002; Cifelli et al.,
2010).
However, some recent studies
evidenced the importance of
compression and vertical movements:
the structure of the Paola Basin, on the
Tyrrhenian side of the Calabrian arc is
an asymmetric syncline filled in with
syn-tectonic Plio-Quaternary deposits
(Pepe et al., 2010). The pre-folding
deposits, Upper Miocene in age, are
cropping out on the mountain range
bounding the basin to the east (Coastal
Range or Catena Costiera). Sediments
of the same age are also cropping out

3
on the eastern side of the Coastal
Range, in a sedimentary basin called
Crati Basin. This is an intramontane
depression interpreted as a graben
(Tortorici et al., 1994), as a
transtensional basin (Tansi et al., 2005)
or as a half graben formed by E-W
extension (Cifelli et al., 2010).
The Crati Basin represent an excellent
area to understand the recent tectonic
evolution of the Calabrian arc, first of
all because of its location right above
the subducted slab and between the
back-arc basin in the NW and the
accretionary complex in the SE.
Secondly it offers the possibility to
observe in the field deposits of
different ages and deformational
features, which is obviously not
possible offshore. Finally the seismic
lines shot in the northern part of the
basin give an opportunity to study the
basin at depth.
The objectives of this study are to
constrain the Neogene evolution of the
Crati Basin in 3D and in particular: to
determine whether its origin and
evolution were controlled by extension
or by compression; to quantify the
magnitudes of horizontal and vertical
movements through time and space
and to relate its evolution to the deep
processes in the Calabrian subduction
zone.
To accomplish these objectives a new
approach was adopted for the study
area: previously unreleased seismic
sections were interpreted and
combined with field observations in
order to understand and describe the
architecture of the basin.
Special importance was attributed to
the geometrical and structural relations
between the basement and the basin
fill, and between the different
sedimentary units.
The style and kinematics of the
structures observed in the field were
analyzed in order to determine the
tectonic regimes during the evolution
of the basin.
Based on the seismic and stratigraphic
data, subsidence curves were
constructed in order to quantify the
magnitudes, the wavelength and the
timing of vertical movements, which
occurred in the different parts of the
basin and on the mountain ranges
around it.
Finally an E-W transect across the
Calabrian arc was created, based on
field data, seismic interpretation and
several literature resources, in order to
link the Crati Basin evolution to the
regional geological framework.
2. Geological setting of the
Northern Calabrian Arc
The main physiographic-geological
provinces of the Northern Calabrian
arc are oriented parallel to the orogen
(N-S): the Paola basin, the narrow
Coastal Range, the Crati basin, the
wide Sila Grande Massif and the
Crotone Basin (Figure 2).
The Crati basin does not extend to the
southern part of this sector: there the
Sila Piccola Ridge runs from the
Tyrrhenian coast in the west until the
Ionian coast in the east.
In the northern sector the Crati Basin
becomes wider, especially towards the
east where it forms a broad plain: the
Sibari plain.
The offshore external part of the
Calabrian Arc is an accretionary wedge
controlled by compressional-
transpressional tectonics which is
bordered by the foreland basin located
in the Ionian Sea (Zecchin et al, 2004;
Ferranti et al., 2008).
The offshore internal part of the Arc is
the Tyrrhenian back-arc basin, with its
two oceanic crust spreading centers:

4
Vavilov (Late Miocene-Early
Pliocene) and Marsili (Pleistocene)
(Sartori et al., 2003).
The northern and southern boundaries
of the northern Calabrian Arc are
represented by major sinsitral strike-
slip zones with a WNW-ESE
orientation, respectively the Pollino
line and the Catanzaro line (Guarnieri,
2003). Strike-slip motion along these
lineaments, occurred from the Middle
Miocene until the Middle Pleistocene,
accomplished the migration of the
Calabrian Arc to SE, simultaneously
with the opening of the Tyrrhenian
Basin (Tansi et al., 2006).
The regional basement is exposed on
the Coastal Range and on the Sila
Massif: it is mainly composed of
Hercynian metamorphic and granitic-
plutonic rocks (Thomson, 1994)
overlain by a Mesozoic sedimentary
cover. These rocks have been stacked
in east verging nappes during the
Apennine orogeny (Eocene-
Oligocene): their P-T history testifies
for a high P/T ratio during
metamorphic climax, typical of
subduction zones (Rossetti et al.,
2004). Their early stages of
exhumation were reconstructed using
high temperature thermochronological
data (Ar/Ar on phengite and Fission
tracks on Zircon and Apatite): this data
indicate a rapid exhumation between
30 and 15 Ma associated with
greenschists retrograde metamorphism
(Thomson, 1994; Rossetti et al, 2004).
Such exhumation was related to major
west verging extensional detachments,
associated to back-arc extension
(Rossetti et al, 2004).
Figure 2: location of the main
physiographic-geological provinces in the
Northern Calabrian Arc
The basement is unconformably
overlain by Neogene sedimentary
sequences deposited in the different
tectonic provinces of the Calabrian
Arc.
Miocene to Recent sedimentary
sequences crop out along the Ionian
side: the Crotone Basin and its offshore
continuation, the Crotone Spartivento
basin, are fore-arc basins characterized
by compressional structures and by a
progressive tilting and depocenter shift
towards the east (Minnelli et al., 2010).
The Miocene deposits cropping out
along the Tyrrhenian side (Amantea
and Paola) were accumulated in an
extensional regime coevally with the
opening of the Tyrrhenian back-arc
basin and with the previously
mentioned extensional detachments in
the Coastal Range (Mattei et al., 2002).
During the Plio-Quaternary the
evolution of the Tyrrhenian side was
controlled by compression, as pointed
out by Pepe et al. (2010): such
compression resulted in the formation
of the Paola Basin syncline and
possibly of the Coastal Range and the
Crati Basin.

5
2.1 The Crati Basin
The Crati basin developed between the
Coastal Range and the Sila Grande
Massif and was filled in with a
sedimentary succession ranging from
Late Miocene to Holocene age (Spina
et al., 2009). According to Spina et al.
(2009), Tortorici et al. (1995) and
Cifelli (2007) the general basin
architecture is controlled by N–S
striking normal faults active since the
Pliocene. Such faults are suggested to
be still active, which is supported by
the occurrence of several earthquakes
in historical time.
According to Spina et al (2009) the
stratigraphic succession of the basin
can be subdivided into five
unconformity-bounded sedimentary
units (Figure 3).
The upper Miocene Unit crops out
along the western side of the basin,
unconformably covering the crystalline
basement rocks: it consist of
conglomerates and arenites evolving
upwards to clays and marls and to
evaporites (Messinian).
This unit is overlain by a Lower-to-
Upper Pliocene succession which
includes two thinning upwards clastic
sub-units. These sub-units are
characterized by continental
conglomerates, which heteropically
evolve to sands and clays towards the
centre of the basin.
The Plio-Pleistocene succession, which
on the western side of the basin
transgressively overlie the Miocene
and Pliocene units, rest directly on the
metamorphic basement on the eastern
side, indicating an eastward migration
of the sedimentation axis (Guarnieri,
2006). The succession is characterized
Figure 3: stratigraphic column of the Crati
Basin, showing the main unconformity-
bounded sedimentary units (Spina et al.,
2009)
by shallow-water marine calcarenites
and conglomerates passing to marine
sands and clays towards the centre of
the basin. This succession is overlain
by Lower to Middle Pleistocene
Gilbert-type fan delta conglomerates
(Colella et al., 2004). The uppermost
deposits, mostly outcropping along the
mountain front, are conglomerates and
sands (Middle Pleistocene) that
unconformably overlie the marine
sediments and represent the remnants
of, formerly wider, alluvial fans
(Tortorici et al., 1995).
A series of marine terraces, formed in
response of the progressive uplift of
the area, characterize the central part of
the Crati Basin and the Sibari Plain:
the elevation of such dated terraces
indicates an average rate of uplift of 1
mm/y since 400 Ka (Santoro et al.,
2009; Ferranti et al., 2009). Little
variations in the uplift rates, in the
order of few tens of meters, were
attributed to active folding (Ferranti et
al., 2009).

6
3. Geological cross-sections
The origin and tectonic evolution of
Crati Basin will be discussed in four E-
W and one N-S geological profiles
(Figure 4). All profiles were
constructed using lithological and
structural/kinematical data gathered
during a field study.
Within the Crati basin the Cervicati-
Bisignano Profile (A-A”’) is the
northernmost E-W profile: besides the
field data a seismic section was used
for its interpretation at depth. The San
Benedetto Ullano Profile (B-B’) is the
middle cross-section and the San Fili
Profile (C-C”) is the southern E-W
section. On the western side of the
Coastal Range a small E-W profile
(Paola Profile E-E’) was constructed to
constrain the evolution of the Coastal
Range. Finally an N-S Profile (D-D’)
was constructed in order to connect the
structures characterizing the three E-W
profiles.
In order to distinguish between the
different tectonic regimes the faults
and their kinematics indicators were
analyzed and a paleo-stress analysis
was conducted using Wintensor
software.
The structural data obtained in the
Crati basin was compared to the data
assembled on the western side of the
Coastal Range, in Paola and Belmonte
Calabro, where extensional
deformation is well documented.
Figure 4: Location of geological cross-
sections and seismic sections

Figure 5: geological profiles across the Crati Basin

3.1 Cervicati-Bisignano Profile A-A’
Plio-Pleistocene UNIT C
Plio-Pleistocene UNIT B
Plio-Pleistocene UNIT A
Upper Miocene
Basement
Figure 6: Cervicati-Bisignano Profile
The Cervicati-Bisignano Profile (Figure 6)
runs from the village of Cervicati in the west
side of the Crati Basin to the village of
Bisignano in the east. Its interpretation at
depth has been constructed using the seismic
line-103.
Main structures
The profile shows a sedimentary basin which
is underlain by faulted basement rocks. The
sedimentary package has been divided into
four sedimentary unconformity-bounded
units, based on the evidence from the seismic
section. The profile shows folded Plio-
Pleistocene strata in the western side and an
undeformed onlapping contact at the eastern
boundary. The folding of the Plio-Pleistocene
strata has resulted in two anticlines and a
syncline with similar NNW-plunging axis and
increasing wavelength towards the east
(Figure 7). In this profile east verging
basement thrust faults accommodate the
shortening at depth and induce buckling of the
overlying sedimentary units.
The western part of the basin
The western boundary of the basin is
presently formed by an east dipping normal
fault which, at depth, is cut by an east verging
thrust fault. E-W shortening, accommodated
by such thrust, has resulted in the folding in
the sediments, which were pushed against the
pre-existing normal fault. The westernmost
anticline is thus interpreted to be a buttress
fold. At present the normal fault seems to be
active, as indicated by historical earthquakes
(Tortorici et al, 1995).
Figure 7: Map view of the folds on western edge of
the basin
Figure 8: Buttress folding evolution sketches.
2 Km

Figure 9: Zoom in the western part of the basin; plots of the bedding and fold axes plunge (anticlines red,
syncline green)
The increase of the folds wavelength towards
the east is interpreted as the result of the
indentation of the Coastal Range, during the
E-W shortening phases.
Three phases of deformation affected the area,
according to the structural data: the first one
was a normal faulting phase, the second one a
folding phase and the third one a tilting phase.
Figure 10: All faults in after correction for bedding
inclination
The Plio-Pleistocene deposits are affected by
both syn- and post sedimentary normal
faulting: such syn-sedimentary faults are
listric and die out with depth. The post
sedimentary faults are usually straight and cut
all layers (Figure 15 &16).
Figure 11: western anticline after
correction for the NNE tilt
Figure 13: all faults after
correction for the NNE tilt
Figure 12: eastern anticline after
correcting for the NNE tilt

The faults are generally NNE-SSW oriented
and the intersection line plunges to NNE.
Their orientation was adjusted for different
bedding orientations, corresponding to the
average flank of the folds (020/20, 325/10 and
030/25) (figure 11). Both the fault
intersection line and fold axes plunge 10 to 15
degrees, respectively towards the NNE and
the NNW, which suggests that both normal
faulting and folding occurred before a north
15 degrees tilting phase.
A correction for such tilt has been done over a
rotation axis with an azimuth of 100 and a dip
of 15. After correction the axes of the folds
become horizontal (N 330) so as the fault
intersection line (N 010) (figure 11 to 13).
The 40 degrees difference between the normal
faulting extension direction (N 100) and the
folding shortening direction (N060) is due
either to block rotation or to stress rotation
between the two phases.
Figure 14: Basement – Pleiocene contact West of Cervicati with a plot of the normal fault
Figure 15: Normal faults in Plio-Pleistocene clays near Cervicati (Mongrassano)
Figure 16: Normal faults in Plio-Pleisticene clays and sands near Cervicati (Mongrassano)

The eastern part of the basin
The eastern side of the basin is characterized
Plio-Pleistocene deposits, generally tilted 5 to
10 degrees to WNW, which are onlapping
against the basement rocks of the Sila Massif.
This indicates that the Sila Massif was already
present and that it was subsiding during
sedimentation. The basement-sediments
contact is gently dipping (10 degrees) towards
the WNW with meters scale paleo-
topography.
The sedimentary package has a coarsening
and shallowing upward trend, passing from
marine clays to fluvial-deltaic conglomerates.
The deltaic system was prograding towards
NW, suggesting an opening of the Crati Basin
towards the north (figure 17 and 18)
As shown by the seismic section a normal
fault occurs at depth on the eastern side of the
basin, which is similar to the abandoned
normal fault on the western side. This fault
created a small wedge in the Plio-Pleistocene
UNIT B and it was cut by a west verging
thrust in a later stage of shortening. Although
the shortening phase has affected the Plio-
Pleistocene strata in the west, it did not have
the same effects on the eastern side.
Figure 17: Plio-Pleistocene conglomerates in Bisignano showing
an average dip towards the NW and foresets prograding to NW
Figure 18: Plio-Peistocene conglomerates in Bisignano
with foresets prograding towards the north ( 360/25)

3.2. San Benedetto Ullano Profile B-B’
Figure 19: The San Benedetto Ullano profile
The general structure of the basin along this
profile is very asymmetrical: the sedimentary
package is faulted and folded in the western
side while in the central and eastern side the
deposits are sub-horizontal and almost
undisturbed. The oldest sedimentary units,
Upper Miocene to Middle Pliocene, crop out
in the western side while Upper Pliocene to
Middle Pleistocene deposits are exposed in
the central and eastern part (Spina et al.,
2009, Guarnieri, 2006).
In the west the contact between the basement
and the Pliocene-Miocene deposits is an N-S
oriented normal fault.
The dip of the fault along the profile is
inferred from the geological maps and from
the Cervicati profile. NW-SE oriented low
angle normal faults affect the basement on the
footwall (Figure 20): this orientation is
oblique to the previously described N-S
oriented normal fault while it is similar to the
orientation of the syn- and post-sedimentary
faults in Paola and Amantea, which affect
Upper Miocene deposits. This suggest that
such low angle normal faulting in the
basement is likely related to Late Miocene
NE-SW extension.
0°
90°
180°
270°
Stereo32, Unregistered Version
Figure 20: Low angle normal faults in the basement crystalline rocks at km 0.8 (WP 47). The basement is overlain by
few meters thick Upper Miocene deposits (conglomerates and sandstones); stereoplot of the fault planes at WP 47.

The most important structure of the profile is
the anticline affecting Miocene and Pliocene
deposits in the western side of the basin: it is
a symmetrical fold with an axis plunging 5
degrees to the north. An east verging thrust
cuts the anticline and upthrows the basement
and the Miocene on top of the Pliocene
deposits; its offset is estimated between 300
and 500 m.
The occurrence of the thrust is inferred by the
large and meso-scale folds affecting the area
(Figure 21). Such mesoscale folds (tens of
meters) affecting the Miocene deposits on the
hangingwall have a general N-S orientation
with 0-10 degrees plunge to the north (Figure
21a). Those affecting the Pliocene deposits in
the footwall have a WNW-ESE axis (Figure
21c). Small normal faults affect the Miocene
marls on the thrust hanging wall (Figure 21b).
The lack of soft sediment deformation
indicates that they are post-sedimentary; their
NNW-SSE orientation is similar to what was
measured in Amantea and Paola. The timing
of faulting is thus probably Late Miocene
while the phase of thrusting and folding is
post Miocene.
Figure 21: Geological cross section between km 3 and km 5 of the San Benedetto profile. The stereoplots display (a) bedding
planes of the folded Miocene deposits: the axis of the folds plunges 0 to 10 degrees to N-NNE. The steeper dips to the west
are due to the fact that the Miocene conglomerates are downlapping to that direction; (b) faults in the Miocene deposits: the
non horizontal intersections can be attributed to measurement imprecision. The extension direction is ENE-WSW; (c)
bedding planes of the folded Pliocene deposits.
Figure 22: Folded Pliocene deposits between km 4.5 and 5 of the San Benedetto profile.

On the thrust footwall NE dipping Late
Pliocene-Early Pleistocene deposits (Spina et
al., 2009) are exposed: sands, clays and
conglomerates, rich of shallow water marine
fossils, organized in cycles of higher-lower
energy and with a general coarsening up-
section trend. The upper part of the sequence
is formed by sub-aerial fluvial deposits. The
sedimentary environment is fan-delta
(Colella, 1988): the foresets, particularly well
expressed in the central part of the basin, and
the current directions indicate that the fans
were prograding towards the E-NE.
The coarsening upwards and the progradation
towards the basin center suggest that the basin
was being progressively filled in and that the
depocenter was shifting towards the east.
This was probably caused by the rapid
exhumation of the Coastal Range and of the
western side of the Crati basin in Late
Pliocene-Early Pleistocene times.
A further shift of the depocenter to the east
occurred while the whole region was being
uplifted and dissected: this is evidenced by
the staircase of fluvial terraces on the western
side of the Crati River and by the position of
the river Upper Pleistocene and Holocene
deposits moved towards the eastern part of the
basin (geological map).
On the river eastern side the shallow marine
Late Pliocene-Early Pleistocene deposits
(Spina et al., 2009) are sub-horizontal or
dipping to the west. These deposits contain
clasts of magmatic and metamorphic origin.
The grain size gradually increases eastwards,
passing from silts to muddy sands, sands with
conglomerates lenses and finally coarse
conglomerates at the contact with the
basement.
These sediments are onlapping on a basement
paleotopography which is characterized by
meters scale irregularities with small
depressions filled by boulders and breccias.
The basement-sediments contact has a 20-25
degrees inclination west of km 16 while it
decreases to 15 degrees in the east. This rapid
change in inclination is interpreted as an
important step in the paleotopography and not
as a fault, since the Plio-Pleistocene
onlapping deposits are undeformed.
Along the N-S profile the top of the basement
is at 800 meters depth at the intersection with
the A-Cervicati profile while it is at zero at
the intersection with the B-San Benedetto
profile. The depth of the basement in the
central part of the A-Cervicati profile is at
2400 m depth therefore, assuming a similar
shape of the basin and a constant thickness of
the Pliocene-Pleistocene package, the depth
of the basement in the central part of the B-
San Benedetto profile can be estimated
around 1600 m (2400-800). The architecture
of the basin at depth has been inferred from
the seismic section along the profile A-
Cervicati (Figure 5) and by the N-S profile
along the western side of the basin (Figure
53).
Figure 23: Pleistocene conglomerates onlap on the basement crystalline rocks at km 16 of the San Benedetto profile

3.3. SAN FILI PROFILE C-C’
Figure 24: San Fili profile.
The basin along this profile is
characterized by two asymmetrical
flanks, with different deformation and
depositional history.
The sedimentary package thickness is
variable and increases towards the centre
of the basin, where the main Miocene to
Quaternary depocenters were located.
The Miocene sediments are only
outcropping on the western flank of the
basin while the Pliocene and the
Pleistocene sediments are outcropping in
the central and eastern part.
The west flank of the profile is
characterized by a large anticline and by
inverse faults which affect Miocene and
Pliocene sediments. The general dip of
the Pliocene-Pleistocene sediments on
the western part of the profile is to NNE,
with inclinations decreasing towards the
central part of the basin (Figure 24).
The eastern flank is characterized by
undeformed sediments onlapping on a
basement paleotopography.
Basin Structure
The description along the profile is made
from west to east and is supported by the
explanations of the main field data and
outcrops.
On the western side of the profile is
characterized mainly by shortening
structures: folds and faults deforming
basement rocks, Miocene and Pliocene
sediments.
The first important structure is a steep
reverse fault oriented 270/70, which
juxtaposes basement rocks on top of
Miocene sediments (Figure 25): such
sediments are affected by a large number
of centimetre- to meter scale high angle
top to the north reverse faults (Figure
27). Such set of faults was considered to
be formed before tilting and for that
reason they were rotated 20 degrees with
an axis of 225° returning the bedding to
a horizontal position. The paleostress
analysis shows a WNW-ESE
compression direction with a strike-slip
component (Figure 25).
Figure 25: Paleostress regime of the most
western part of the profile.

Figure 26: Outcrop with mayor reverse fault which contact the basement and Miocene sediments
(270/70), on the right reverse patter of faults. .
One of the main shortening structures on
the western side of the Crati basin is an
anticline affecting mainly the Miocene
package (800 m of conglomerates, sands
and muds), which is cut by an east
verging thrust. The core of the anticline
is composed of highly deformed
basement rocks.
The anticline has a 2.5 km wavelength
and its axis is generally oriented NNW-
SSW: this structure can be followed for
over 20 km in north-south direction
(Figure 28 and geological map). Some
minor changes of the fold axis are
attributable to local changes in
compression direction or to a strike-slip
component of motion along the faults:
in the south the anticline axis plunges to
360/08, in the central part to 031/04 and
in the north to 350/10, resulting in a
gentle dome structure (Figure 27).
For the Miocene sediments the anticline
is quite symmetric with similar
inclinations on both flanks, ranging from
15 to 25 degrees (Figure 27).
The strike of the Pliocene sediments
differs from the Miocene: interestingly it
is roughly parallel to the N350 striking
inverse fault which bounds the east flank
of the anticline (3000 m from start point
of the profile). This suggests a fault
control on the Pliocene sediments tilt
and orientation. This difference between
the Miocene and the Pliocene dips could
be due to two different reasons:
-Two compressional phases occurred,
one that created the anticlinal structure
and a second phase which created the
inverse faults affecting the Pliocene
sediments and controlling their
orientation.
-One tectonic phase which created both
fold and faults but with an amplification
of the tilting of the Pliocene sediments
due to drag under the thrust fault.

45
15
20
60
55
15
40
20
40
20
45
20
20
25
40
20
15
15
N
1
2
3
1
3
2
Anticlinile Axis
Figure 27: Map with the main bedding directions used to reconstruct the shape of the anticline on the
Miocene sediments. On the left, stereoplot of the three fold axis segments reconstructed
Figure 28: East flank of anticline and different paleostress analysis for synsedimentary and
postsedimentary normal faults.
The Miocene sediments on the east flank
of the anticline are deformed by syn-
sedimentary and post-sedimentary
normal faults, which indicate that the
area was under tensional stress during
and after deposition of Miocene
sediments (Figure 28).
The post-sedimentary normal faults are
characterized by high angle planes, with
a maximum offset of 40 cm. They seem
to be formed after tilting of the layers,
with extension direction of around N053
and with an important strike slip
component (Figure 29 & 30). The syn-
sedimentary normal faults have low

angle fault planes and form wedges in
the sediments package (Figure 31). The
original orientation of the faults, before
compaction and tilting was calculated
first rotating the bedding back to
horizontal (15 degrees on a N040
rotation axis) and then 20 degrees
inclination were added in order to
correct for the sediment compaction. The
orientation and the kinematics of these
faults indicate a NNE-SSW extension
direction (Figure 32).
The orientation of the post-sedimentary
faults indicates an N-S extension
direction (Figure 33) thus suggesting a
rotation of the stress field after
sedimentation or local changes of such
field.
Figure 30: High angle post-sedimentary and
post-tilt normal faults, affecting Miocene
sediments in the western flank of the anticline.
Figure 31: Syn and post sedimentary faults affecting Miocene sediments.
Figure 32: Synsedimentary normal fault planes. Original data (top left), rotated data (top right) with
Rotation axis of 40° and returning bedding at horizontal position -15° and paleostress regime after
adding 20 degrees for compaction in outcrop 67 (bottom).

Figure 33: Paleostress analysis for post-
sedimentary faults affecting Miocene
sediments in the east flank of the anticline,
extension direction N-S.
On the eastern flank of the anticline a
major inverse fault forms the contact
between Miocene and Pliocene
sediments at the surface: it juxtaposes
basement and Miocene rocks on top of
Pliocene sediments. The offset of the
fault has been estimated around 350 m,
according to the thickness of the
Miocene and Plio-Pleistocene sediments
on the fault hangingwall.
This fault dragged the sediments on the
footwall, resulting in a local steepening
of the bedding close to it. The sediments,
strongly inclined close to the fault, get
progressively less inclined to the central
part of the basin. These Pliocene
sediments have been affected by a
compressional phase before they were
tilted: this is supported by a family of
syn-sedimentary thrusts, characterized
by soft sediment deformation bands
(Figure 37), that are deforming Pliocene
sediments on the major fault footwall.
The inverse kinematics of such faults,
taking into account their syn-
sedimentary origin, was deduced by
rotating the bedding back to horizontal
(60 degrees around a N340 rotation axis)
and thus reconstructing the original pre-
tilting setting (Figure 34). The paleo-
stress analysis indicates a NNW-SSE
compressional regime.
Figure 34: Original data (top), and paleostress
analysis for the rotated data (bottom)
(rotation axis of 340° and returning bedding
at horizontal position -60°).

Figure 35: Tilted and faulted Pliocene sediments close to the eastern inverse fault.
Figure 36: Faulted contact between Miocene
and Pliocene sediments. Showing the change
in inclination of the bedding next to the fault
zone and how it decreases towards the central
part of the basin.
Towards the east of the profile the
Pliocene sediments are mainly composed
of marine deposits with alternation of
conglomerates, sands, and clays and
with beach and deltaic facies.
Finally the sediments on the eastern
flank of the basin are tectonically
undeformed and onlap a basement
paleotopography. Such paleotopography
is characterized by several breaks in the
slope, with a staircase-like shape,
passing from gentle to steeper
inclinations towards the central part of
the basin (Figure 24).
3.4. North - South profile
This geological profile runs from north
to south along the western side of the
Crati Basin and intersects all three
previously described profiles (Figure
53). It was constructed in order to link
the profiles and in particular to constrain
the geometry of the folds observed in the
E-W profiles and to evaluate the
differences between the northern and the
southern part of the basin.
Basement metamorphic and magmatic
rocks crop out in the extreme south. In
most of the profile they are covered by
Miocene to Early Quaternary deposits.
The total thickness of the Miocene
package diminishes towards the center

of the profile, passing from 500 m in San
Fili to 250 m in along the San Benedetto
Ullano profile and increasing again to
350 m in the northern part of the profile.
The Pliocene deposits are conformable
above the Miocene ones.T
he general structure of the profile is
characterized by a general dip to the
north. This dip is, however, not uniform
since the whole sedimentary package is
gently folded: a syncline occurs between
the San Fili and the San Benedetto
profiles and an anticline, with two small
structural highs, occurs between the San
Benedetto and the Cervicati profiles.
Towards the northern end of the profile
the layers are constantly dipping to the
north. The apparent wavelength of the
large syncline and anticline is 10-15 km.
The smaller folds between the San
Benedetto and the Cervicati profile have
a 5 km wavelength. These undulations
are due to the fact that the folds in the E-
W profiles are not parallel to this profile.
3.5. Belmonte Calabro Area
Belmonte Calabro is situated on the
Tyrrhenian coast, south of Paola (Figure
2). Miocene deposits (Serravallian to
Messinian) are cropping out in this area
(Mattei et al., 1999 and 2002). The
deposits are continental to shallow
marine and are organized in two major
fining upward cycles: from coarse
conglomerates and breccia to well sorted
red sandstones until red muddy sands.
The sedimentary environment is fan
delta with delta plain, prodelta and tidal
flats facies (field observations).
The sedimentary package is regionally
tilted to the WSW and is heavily
affected by normal faulting. The
sedimentary architecture and the
structural data of this region were
analyzed in order to compare it to the
Crati Basin and to constrain the
evolution of the Coastal Range, which
divides these two areas. Most of the
faults display soft sediment deformation
features such as deformation bands,
anastomizing extensional duplexes,
slumping and small scale folding
associated to faulting.
Some of the faults produced wedging in
the sedimentary package. They often
have low angle fault planes and
terminate in fine grained layers (Figure
38): they can be considered syn-
sedimentary (family 1). All other faults
with no wedging but with clear soft
sediment deformation features (figure 2)
formed shortly after the deposition of the
sedimentary package (family 2).
Finally another family of faults does not
display any of the previously described
features: they formed in a later stage of
deformation (family 3).

Figure 38: faults affecting the Miocene deposits in Belmonte Calabro, outcrop L2. Most of the faults belong to
family 1 (syn-sedimentary). Those with higher angle fault plane (100/60; 250/70; 240/80 and 230/80) belong to
family 2 (conjugate normal faults).

Figure 39: faults affecting the Miocene deposits in Belmonte Calabro, outcrop L1 (family 2)
Figure 40: conjugate normal faults (family 2) of outcrop U5.
The orientation of the family 1 faults indicates
an E-W stretching direction (Figure 41 to 44).
The faults of family 2 are conjugate normal
faults which systematically cross cut the low
angle family 1 faults (Figure 38). Their
orientation and kinematics indicates an ENE-
WSW extension direction (Figure 44 to 46).
Since the normal faults are conjugate, they
were supposed to form symmetrically with
respect to a vertical axis. Therefore the
asymmetry of the fault planes with respect to
a NNW-SSE axis (Figure 41, 44 & 46) is
likely due to the tilt to WSW: the fault planes
become symmetrical with respect to a NNW-
SSE axis by rotating the bedding back to
horizontal (Figure 44 and 46). This suggests
that family 2 formed before the tilting to the
WSW.
The very oblique striations to NNW on WSW
dipping fault planes are in apparent contrast
with the conjugate origin of family 2 faults. A
possible explanation is that they were
reactivated as oblique dextral faults in a later
strike-slip deformation phase characterized by
N-S sigma 1 and E-W sigma 3 (Figure 45b).
Oblique slip occurred along family 3 faults,
too (Figure 47): the paleostress analysis
suggests two possible best fitting tensors: E-
W extension or transtension with a NE-SW
maximum horizontal stress.

0°
90°
180°
270°
Equal angle projection, lower hemisphere
N total = 34
n=33 (planar)
n=1 (linear)
0°
90°
180°
270°
Equal angle projection, lower hemisphere
N total = 34
n=33 (planar)
n=1 (linear)
Figure 41: fault planes of faults in outcrop L2 (figure 1). Family 1 in yellow, family 2 in black. a: without
rotation; b: with rotation (45 degrees, N330 axis)
Figure 42: Paleostress analysis for the fault in outcrop L2 (figure 38). a: family 1 faults (syn-sedimentary); b:
family 2 faults.
0°
90°
180°
270°
0°
90°
180°
270°
0°
90°
180°
270°
Figure 43: (a) Faultplanes of faults in outcrop U1 (family 1). The faults with major offset are evidenced in red. Bedding in
green. (b and c) fault planes and transport direction of the faults in figure 2 (outcrop L1). (a): without rotation; (b): with
rotation (15 degrees, N360 axis). Bedding in green; faults with clear soft sediment deformation features in yellow.

Figure 45a and 45b: paleostress analysis for the faults in figure 2 (outcrop L1). 41b taking into account the
oblique striations.
0°
90°
180°
270°
0°
90°
180°
270°
Figure 46: Faultplanes of faults in outcrop U5. Faults with metric offset are evidenced in red. Bedding in green.
a: without rotation; b with rotation (25 degrees, N345 axis).
0°
90°
180°
270°
Figure 47: (a) Faultplanes and transport direction of faults in outcrop U4 (family 3); paleostress analysis: (b)
pure extensional regime, (c) transtensional regime (sigma 1 = sigma 2; stress ratio=1)
The different phases of deformation affecting
this area are here summarized:
- 1: normal faulting of
Serravallian/Tortonian age (family 1 and
2 faults) with E-W to WSW-ENE
extension direction.
- 2/3: reactivation of the normal faults in a
strike-slip regime (E-W sigma 3).
- 2/3: regional tilt to WSW.
- 4: oblique slip faulting (family 3 faults)
in an extensional (E-W sigma 3) or
transtensional (NW-SE sigma 3) regime.
These results are quite similar to the data of
Mattei et al. (2002) but with some important
differences. The regional homoclinal structure
dipping to WSW is due, according to Mattei
et al. (1999), to domino faulting which
defined several tilted blocks, progressively
downthrown towards the E. However our data
suggests: (a) no preferential transport
direction, since both top to the east and top to
the west faults are equally represented and the

amount of offset is similar; (b) the regional
tilt is younger than normal faulting.
Furthermore the domino structure with major
E dipping normal faults described by Mattei
et al. is not likely to be coeval with the uplift
of the Coastal Range: an opposite orientation,
with major W dipping faults, would more
likely occur.
This suggests that the Upper Miocene
extension and the formation of the Amantea
basin predate the uplift of the Coastal Range
and that such uplift produced the regional tilt
to WSW.
3.6. Paola profile
Figure 48: The Paola profile
The Paola profile runs from the Tyrrhenian
coast in the west to the crystalline rocks
outcrops of the Coastal Range in the east
(Figure 48).
Terraced Quaternary deposits (beach
conglomerates) are unconformably overlying
west dipping Upper Miocene deposits
(Robustelli et al., 2004) in the western side of
the profile. Two orders of terraces are present
with respectively 50 m and 120 m elevation
(based on fieldwork observations; Sorriso
Valvo et al., 1991; Robustelli et al., 2004). An
erosional terrace is located in the eastern side
of the profile at 350 m elevation above sea
level. According to Sorriso Valvo et al.
(1991) and Robustelli et al. (2004) these
marine terraces have been uplifted at around 1
mm/a in the last 400 Ky.
The Miocene deposits are characterized by
well layered marine sandstones and muds in
the west, passing downsection to marine
sandstones and conglomerates and to
continental red conglomerates at the contact
with the basement. The inclination of the
bedding gradually increases to the east, from
15 degrees near the coast to 30 degrees at the
contact with the basement. This contact is an
unconformity showing no clear indication for
onlapping or downlapping therefore the
topography at the onset of sedimentation was
probably minimal. The change in sedimentary
facies indicates a progressive increase in the
water column during deposition which was
related to a transgression phase (Mattei et al.,
2004; Robustelli et al., 2004). The fact that
the onlap to the east was not observed in the
Terrace 1
Terrace 2
Erosional
Terrace

field probably depends on the very small
onlap angle.
In the area of Fuscaldo the Miocene deposits
are affected by syn-sedimentary normal faults
(Figure 49&50). They are conjugate sets,
NNW-SSE oriented, with an ENE-WSW
extension direction.
These syn-sedimentary faults are
characterized by low angle fault planes
terminating in finer grained layers, by shear
disaggregation bands and by slumping. The
pattern of fault planes is asymmetrical with
respect to a NNW-SSE axis, with steeper
WSW dipping faults. By restoring the
bedding (45-50 degrees dip angle) back to
horizontal the pattern is also very
asymmetrical with the ENE dipping faults
becoming vertical. A symmetrical pattern is
reached with a 20 degrees rotation. This
suggests that, in the area of Fuscaldo, a phase
of tilting (20-25 degrees) occurred before syn-
sedimentary faulting while another one (20
degrees) after that.
Post-sedimentary faults affect the Miocene
deposits in the area of Paola (Figure 51): they
are characterized by the complete lack of soft-
sediment deformational features. The
extension direction is ENE-WSW. This phase
of faulting occurred after the tilt to WSW, as
evidenced by the symmetrical pattern of the
fault planes with respect to a NW-SE axis.
The age of tilting in Paola is, similarly to
Belmonte Calabro, post-Miocene: it is most
likely related to the Plio-Pleistocene uplift of
the Coastal Range. Such tilting was not
uniform: the geometrical architecture of the
Miocene deposits suggests that they have
been folded (Figure 49). The anticline in the
east is likely represented by the Coastal
Range while the syncline in the west is
represented by the Paola Basin (Pepe et al.,
2010).
Figure 49: schematic architecture of the Miocene
deposits in the area of Paola. Sketch A (folded
Miocene) and B (wedging/syn-tectonic Miocene)
display two possible geometries which fit the
observed bedding measurements. Sketch B displays
a retrogressive sequence with pinch-out positions
shifting to the sea (westwards). However both field
observations and literature data (Mattei et al., 2002;
Robustelli et al., 2004) indicate that the Miocene
deposits are transgressive therefore such a scenario
is not realistic. A wedging-transgressive Miocene
scenario is shown in sketch C. This is also not
realistic since it does not fit the observed data. The
most likely scenario is thus a folded Miocene
package (A).

.
Figure 50: Syn-sedimentary faults in Miocene sandstones and conglomerates near Fuscaldo (O1). Faults stereoplots: (a)
non rotated, bedding in green; (b) rotated; bedding in green. Rotation axis N 350, 50 degrees rotation.

Figure 51: Syn-sedimentary faults in Miocene sandstones and conglomerates near Fuscaldo (O2).
Faults stereoplot: (a) non rotated, bedding in green; (b) rotated, rotation axis N360, 45 degrees rotation
Figure 52: Faulted Miocene deposits at km 1.6 along the Paola profile. From bottom right to top left: granite (basement); very
coarse continental red conglomerates; white-yellow sands and conglomerates with calcareous cement.

4. Geological Map
The geological map was constructed
using previously released geological
charts (scale: 1:25000) retrieved from
Servizio Geologico d`Italia and
structural and kinematical data
acquired during fieldwork.
The map shows the Miocene-to-
Quaternary deposits of the Crati Basin
in between the Sila Massif in the East
and the Coastal Range in the West.
The profile lines correspond to the
previously described geological cross
sections. The structures displayed in
solid lines on the map represent the
actual field observations and
measurements while the dashed lines
represent the interpreted continuations
of such structures.
Older sedimentary units, Miocene and
Pliocene, outcrop in the western side of
the basin whereas younger ones, Plio-
Pleistocene, in the central and eastern
part. The Crati River and its Holocene
deposits are close to the basin eastern
boundary.
The main structures are located in the
western part of the basin: two east-
verging thrust affect basement and
Figure 54: Geological map of the research area

basin fill deposits along the southern
profile. The eastern one is associated
with a large anticline with a 6 km
wavelength, which extends along the
whole western part of the basin. This
fold is characterized by axial
undulations, clear in the N-S profile,
and its general plunge is to N or NNW.
Smaller scale folds affect the basin
deposits on the western flank of the
anticline, i.e. on the thrust hanging
wall.
In the NE part of the basin the thrust
do not cut the surface: the outcropping
deposits are only affected by folding
and are bounded to the west by a major
N-S striking normal fault. Such fault is
an old fault, probably active in the
Miocene, which acted as an indenter
during the Plio-Pleistocene shortening
phase, inducing buttress folding of the
basin fill deposits.
The central profile displays an
intermediate situation between the
northern and the southern profile, with
the eastern thrust cutting the surface,
with folds and with the normal fault
bounding the basin to the west.
This setting is explained by a younger
activity of the thrusts in the south with
respect to the north, which also
produced larger vertical offsets and
uplift. Erosion played a role too, since
the higher magnitude of uplift probably
induced a higher amount if erosion so
that, in the south, the topography
intersects the geological structure at
deeper levels. This is why, at the same
altitude, older units outcrop in the
south while younger units in the north.
The eastern side of the basin is almost
undisturbed: the Plio-Pleistocene
sediments onlap on the basement
towards the east and are dipping 5 to
10 degrees towards the W or NW.
5. Discussion
The present configuration of the Crati
Basin as an intramontane sedimentary
basin resulted from a series of
compressional an extensional stages.
This is visualised in figure 55 where
the evolution of the basin is shown in
different time slices from Tortonian to
present and in the diagrams of figure
56 where subsidence curves for
different parts of the basin are
visualized. The Plio-Pleistocene
sediments were subdivided into four
units based on seismic interpretation.
After the middle Pleistocene the
evolution scheme is split in to two in
order to clarify the difference in
evolution between the northern and
southern of the basin.
5.1 Pre-Tortonian
According to Molin et al. (2004) and
Olivetti (2008) the uplift of the Sila
plateau started in the Lower
Pleistocene. However the onlapping
relation between Mio-Pliocene
sediments with the basement shows
that the Sila Massif formed already an
important relief before and during
Miocene. This is also supported by the
high rates of exhumation from 30 to 15
Ma (Oligo-Miocene) (Rossetti et al.,
2001, 2004) and by the absence of
Oligocene to Middle Miocene deposits
in the entire region.
5.2 Tortonian
During the Tortonian the Crati basin
got filled in by 300 to 600 m of
transgressive continental to shallow
marine deposits. The basin was bound
by the Sila Massif in the east:
according to Barone et al. (2008) the
western and central parts of the Sila
Massif were already exposed during
the Upper Miocene, as indicated by the
provenance analysis on Miocene
deposits of the Crotone basin.

The basin was in connection with the
Paola and Amantea area in the west.
The Coastal Range was not there yet,
though it might have formed a small
submarine relief. Field and seismic
evidence indicate that the present day
relief of the Coastal Range formed
mainly after the Miocene:
(a) the westwards tilted Upper
Miocene sediments are parallel to the
contact with the basement both in the
offshore Paola basin (Pepe et al.,
2010) and onshore around Paola (field
observations); (b) the Upper Miocene
marine sediments (Mattei et al., 2002)
are outcropping at different elevations
within and on top of the Coastal Range
(field observations).
Normal faulting was active during
sedimentation on both flanks of the
basin, controlled by a NE-SW
tensional regime. The increase of water
depth through time (Mattei et al.,
2002) suggests that sedimentation
could not keep pace with subsidence
therefore subsidence must have been
related to crustal or lithospheric scale
dynamics rather than being purely fault
controlled.
The Sila Massif was the main source of
sediments during this period. The
wedging of Miocene sediments in the
Crotone Basin indicates its relative
uplift during this period (Massari et
al., 2002 and Zecchin et al., 2004).
5.3 Messinian
The Messinian was characterized by
deposition of a thin package of
evaporites, induced by the
Mediterranean sea level drop.
Compression took over extension and
resulted in the relative uplift of the Sila
and the Coastal Range with respect to
the basin.
5.4 Unit A (Early-Middle Pliocene)
A 200-300 m thick unit of
transgressive continental deposits was
accumulated in the central part of the
basin, onlapping on both flanks of the
basin: this suggests phase of
generalized subsidence. The
depocenter migrated to the east, with
respect to the Miocene one. The region
was affected by NNE-SSW shortening
and strike-slip deformation: thrusts
developed on both sides of the basin
and resulted in the relative uplift of the
Sila and of the Coastal Range with
respect to the basin centre.
5.5 Unit B (Middle-Late Pliocene):
Ongoing shortening on the basin
western side was coeval with normal
faulting, which affected mainly the
central and western part of the basin.
The basin became wider and the
accommodation space increase both
due to regional subsidence and to the
reactivation of Miocene normal faults.
West dipping syn-sedimentary normal
faults developed in the central part of
the basin, creating major sedimentary
wedges. The extension direction
indicated by the faults orientation is
NE-SW.
The transgressive sedimentary package
is conformable with unit A in the west
while it is downlapping in the central
part of the basin; it onlaps both basin
flanks and is characterized by the
passage from continental to shallow
marine and then to deeper marine
deposit, indicating an increase in water
depth with time. The thickness of the
package increases towards the basin
centre: this is related to the filling of a
paleotopography but also to sediment
load and tectonic subsidence. The
Coastal Range was uplifted as a large
scale anticline (tens of kilometres) and
also thanks to thrusting on its sides.
The Sila Massif experienced
subsidence, as indicated by the
onlapping deposits in both the Crati
and the Crotone basin (Barone et al.,
2008).

5.6 Unit C (Late Pliocene-Middle
Pleistocene)
During this period marine to
continental deposits were accumulated
in the Crati Basin: the facies transition
indicates a diminishing water depth.
The subsidence curves the start of
indicate tectonic uplift and folding in
the western part of the basin.
Subsidence still occurred in the central
part of the basin because of sediment
load. The basin became wider,
especially towards the east. This shift
of depocenter to the east is also
suggested by the subsidence of the
eastern side of the basin, coeval with a
relative uplift of the basin swestern
side.
Tectonic deformation occurred mainly
in the basin western flank: east verging
thrusts affected the basin fill and folds
started to develop. This is particularly
evident in the south, where thrusts
have higher offset and the anticline has
higher amplitude than in the north.
The abandoned normal fault on the
Coastal Range side acted as a
boundary for buckling, thus inducing
buttress folding.
5.7 Middle Pleistocene to present
The whole region experienced
generalized uplift. The elevation of the
marine terraces in the northern part of
the basin and on the Tyrrhenian coast
indicates that around 400 m uplift
occurred in the last 400 ky (Ferranti et
al., 2009). Different values are
obtained on a NW-SE profile across
the Calabrian Ar: the different ages of
the uplift onset suggest a migration of
the uplift wave towards the SE, starting
in the Early Pleistocene on the
Tyrrhenian coast (Robustelli et al.,
2004), at 400 Ka in the Sibari plain
(Ferranti et al., 2009) and at 200 Ka in
the Crotone Basin (Massari et al.,
2002).
The uplift of Coastal Range and of the
basin western side was higher due to
folding amplification and east verging
thrusting, accommodating ENE-WSW
shortening. As during deposition of
unit C, the offset of the faults and the
amplitude of the fold were higher in
the southern part of the basin: here the
thrusts cut the surface while in the
north they only induced folding of the
overlying sediments.
The amount of uplift on the anticline in
the southern part of the basin can be
quantified by adding the thickness of
the eroded sedimentary package
(Miocene, Unit B and C) to the present
day topography: the value ranges
between 1000 and 1500 m.
This indication for active folding is in
agreement with the morphological data
in the Sibari Plain, displaying different
patterns of terraces uplift related to
reactivation of basement folds
(Ferranti et al., 2009).
The fast uplift of the Coastal Range led
to the development of several alluvial
fans on the western side of the basin
and resulted in the shift of the Crati
River course towards the east, as
evidenced by the fluvial terraces on the
river western side.

Figure 55: Tectonic evolution of Crati basin, vertical and horizontal movements in the basin since Tortonian to present.

Anticline
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0123456
Age (Ma)
Depth(Km)
East
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0123456
Age (Ma)
Depth(Km)
Syncline
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0123456
Age (Ma)
Depth(Km)
Basin center
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0123456
Age (Ma)
Depth(Km)
Syncline Anticline Basin
centre
East
Figure 56 : Subsidence curves for synthetic wells in the Crati Basin along the A-Cervicati profile.
Plio-Pleistocene units based on subdivision and chronology of Spina (2009). 5 to 3 Unit 1; 3 to 1.5 Unit 2; 1.5 to 0.7-0.4 Unit 3.
Error bars on the X-axis are due to age uncertainties while error bars on the Y-axis are due to paleo-water depth uncertainties.

6. Geological profile across the Calabrian Arc
Figure 58: schematic E-W geological cross section across the Calabrian arc and its location.
A
B

Figure 59: interpreted E-W seismic sections across (a) the Paola Basin (Pepe et al., 2010) and (b)
the Crotone Spartivento Basin (Minnelli and Faccenna, 2010).
In order to link the development of the
Crati Basin to the regional tectonic
framework a schematic geological
profile was drawn across the Calabrian
arc, from the Tyrrhenian sea in the
west to the Ionian sea in the east, using
seismic and geological sections from
the literature (Massari et al., 2002,
Zecchin et al., 2004; Minnelli and
Faccenna, 2010; Pepe et al., 2010) and
our own section of the Crati Basin.
The main features of the profile are the
three sedimentary basins: Paola, Crati,
Crotone with its offshore continuation
Crotone-Spartivento, separated by two
mountain ranges: the Coastal Range
and Sila Massif. Two other structural
highs occur offshore: the anticline
located west of the Paola Basin and the
frontal thrusts of the orogenic wedge in
the Crotone Spartivento Basin (figure
58).
The sedimentary basins are filled with
Miocene to Quaternary deposits. The
thickness of these packages varies
from basin to basin, according to the
different magnitude and timing of
subsidence and uplift (Figure 61).
The changes in thickness of the
Miocene deposits along the profile are
very gradual. The Miocene package is
thicker in the centre of the Paola and
Crotone Spartivento basin and it is
pinching out towards the Sila Massif
on both sides.Iin the Crati Basin it is
much thinner than in the other basins,
with circa 350 m along the A-Cervicati
profile. These indications suggest that
(1) the Coastal Range was not a relief
in the Miocene yet and that the present
day topography must have been
created in a later stage, as also pointed
out by the outcrop of Miocene marine
deposits at high elevation in the range;
(2) the Sila Massif formed already an
important paleo-topography in the
Miocene, which is also evidenced by
the provenance analysis in the Crotone
basin (Barone et al., 2008).
It is the Plio-Quaternary package
however, that displays the most
dramatic changes in thickness within
each of the three basins. The general
pattern is characterized by a central
area which experienced strong
subsidence flanked by two domains
where subsidence was less important.
In particular vertical movements seem
to have operated at a smaller
wavelength than in the Miocene. As
described by Pepe et al. (2010) the
Paola basin developed as an

Figure 61: wavelength geometries throughout the Calabrian Arc
asymmetric syncline with a 37-40 km
wavelength (Figure 60a). The Crati
basin width ranges from 10 to 15 km.
In the Crotone Spartivento basin the
early Plio-Pleistocene deposits were
accumulated in a 30 km wide
depocenter and, in a later stage, in a 10
km wide one, corresponding to a
syncline (Figure 60b). The width of
the onshore Crotone basin, separated
from the Crotone-Spartivento Basin by
a major thrust zone, is around 30 km.
Pepe et al. (2010) suggested that the
basement rocks outcropping in the
Coastal Range could correspond to the
anticline lying to the east of the Paola
Basin syncline, and estimated a
wavelength of 36 km, which makes it
comparable to the syncline (Figure
59). The Sila Massif forms a sigle
unaffected block which is much
broader than all other structural
features and displays a flat morphology
typical of old peneplains.
Since the Middle Pleistocene
generalized uplift occurred in Calabria
(Bordoni and Valsenise, 1998;
Ferranti et al., 2009) at a rate around 1
mm/y based on the height of uplifted
marine terraces (Westaway, 2007;
Ferranti et al., 2009). During this
phase the Crati and the Crotone basin
were uplifted and dissected by erosion.
At the same time the offshore domains,
both on the Tyrrhenian and the Ionian
side, experienced strong subsidence.
The wavelength of such vertical
movements is estimated around 300-
400 km by Pepe et al. (2010) (Figure
59). This pattern of different vertical
movement wavelengths is visualized in
figure 61.
Figure 60: subsidence curves of the Paola, Crati and onshore Crotone basin. The curves of the
Crati and the Crotone basin have similar shape, displaying an increase of subsidence in Pliocene,
a decrease in subsidence in the Quaternary and uplift from the Middle Pleistocene. The Paola
basin is characterized by rapid subsidence also during the Quaternary.
Paola Basin
-6
-5
-4
-3
-2
-1
0
1
024681012
Age (Ma)
Km
Crati Basin
-6
-5
-4
-3
-2
-1
0
1
024681012
Age (Ma)
Km
Crotone Basin
-6
-5
-4
-3
-2
-1
0
1
024681012
Age (Ma)
Km

The reason for these vertical
movements can be linked to orogenic
wedge dynamics and, in general, to the
evolution of the subduction system.
1- The fast exhumation rates registered
by thermochronological data (Thomson,
1994; Rossetti et al., 2004)
characterized a stage prior to the
evolution of the present day basins and
are related to the uplift of the Sila
Massif.
2-The generalized subsidence during
the Late Miocene was likely induced by
the tensional regime related to the
rifting in the Tyrrhenian Sea (Mattei et
al., 2002).
3-The Pliocene-Quaternary vertical
movements were controlled by
compression. Subsidence in the Crati
and in the Crotone-Spartivento basin
with respect to the Coastal Range and
to the Sila Massif was induced by
crustal folding, thrust load and was
further enhanced by sediment load
(Minnelli et al., 2010; own
observations) while in the Paola Basin
subsidence was triggered by crustal
scale folding. Normal faulting in the
Crati Basin during this phase was
induced by gravitational collapse.
During this period the migration of the
subduction system to SE was coeval
with the episodic oceanization of the
Tyrrhenian Sea, i.e. the formation of
the Vavilov and the Marsili basin
(Funiciello et al., 2004). This
migration was accomplished at the
surface through a system of strike-slip
faults (sinsitral in north Calabria,
dextral in Sicily) and through slab tears
at depth (figure 62) (Mattei et al.,
2007; Chiarabba et al., 2007; Neri et
al., 2009; Ferranti et al., 2009). This
resulted firstly in different velocities of
migration to the SE, with the Southern
Calabria and NE Sicily block moving
faster than the rest. Secondly it induced
secondary patterns of mantle flow,
originated from the steepening and
retreat of the slab (Malinverno and
Ryan, 1986; Faccenna et al., 2005).
We speculate that the fast retreat
velocity of the central block induced
extension, also onshore (figure 62). In
northern Calabria and Sicily the slow
migration velocity and possibly the
toroidal component of mantle flow
around the slab resulted in shortening
(Guarnieri et al., 2007; Elter et al.,
2003).
4-The long wavelength of vertical
movements (Pepe et al., 2010) from
Middle Pleistocene to present, creating
a phase of onshore uplift and offshore
subsidence, was probably caused by the
blocking of the subduction system due
to the too narrow slab, inadequate to
actively subduct (Mattei et al., 2007,
Funiciello et al., 2004).
The uplift was probably also enhanced
by the slab detachment, with
consequent weakening slab pull and
isostatic response.
Figure 63: tectonic regimes in the Calabrian Arc during
the Plio-Pleistocene

7. CONCLUSIONS
A combination of seismic interpretation
and field data have resulted in a 3D
model of the Neogene evolution of the
Crati Basin and the different
deformation phases which led to its
present day configuration.
The Crati Basin is a sedimentary basin
with a 2.5 km thick sediment
succession, mainly affected by
shortening structures and with a
marked asymmetry in the deformation
between its flanks: the eastern side is
characterized by sub-horizontal strata
of Plio-Pleistocene age, tectonically
undeformed and onlapping against the
basement paleotopography of the Sila
Massif. The western flank shows a
completely different configuration,
characterized by folded Miocene and
Plio-Pleistocene strata which are cut by
several thrust faults.
Stresses acted differently in the south-
western and north-western flanks of the
basin, resulting in different structural
geometries. The north-western flank of
the basin is currently formed by an east
dipping normal fault, which is cut by a
younger east verging thrust which
induced buckling in the overlying
sediments.
The south-western flank experienced
more shortening, with higher fault
offsets and amplified folds.
The tectonic evolution of the basin was
characterized by extension in the Late
Miocene and by almost continuous
shortening in the Plio-Quaternary.
The Sila Massif formed already an
important paleotopography before the
basin formation while the Coastal
Range developed during the Pliocene,
separating the Paola from the Crati
basin. Thrusting, crustal scale folding
and only locally normal faulting are the
dominant deformation mechanisms
controlling the basins evolution in the
Northern Calabrian Arc.
Further research
Further studies on the Crati Basin
should investigate its northern and
southern boundary in order to evaluate
the influence of orogen-perpendicular
structures, and in particular strike-slip
faults, on the basin evolution. The area
south of Cosenza, Belvedere Calabro
and the southern side of the Pollino
Ridge would be good regions for such
an analysis.
The area studied in our work could be
the focus for other methods of research.
In particular a tectonic-
geomorphological analysis could be led
in order to detect information about
rates and magnitudes of displacement
along active faults and folds.
This analysis could be based on
different sources and methods:
displacement of fluvial and marine
terraces; knick-points along
longitudinal river profiles; variations of
valleys width and shape; captures and
river deviations; fault scarp degradation
modelling.
The eastward flowing rivers,
originating from the Coastal Range, are
good study candidates because they
cross all the main basin geological
structures: field and map observations
evidenced how the river valleys
become broader and filled in by recent
deposits east of the big NNW-SSE
oriented anticline. River terraces and
alluvial fans seem to be preserved only
in the synclines and not on the
anticlines, where they rivers are deeply
entrenched. The course of the rivers in
the San Fili area and in the Torano area
appears to be deflected to the north,
possibly as a consequence of the lateral
northwards fold growth. The same
process could be the cause of the north
tilt of the alluvial fans near San
Vincenzo la Costa.
A further line of research is lithospheric
scale analogue and numerical
modelling: possible research questions
could be how to produce a shortening

sedimentary basins in a back-arc
setting; what is the influence of slab
detachment and secondary patterns of
mantle flow on topography and on the
upper plate superficial stress regime;
what kind of tectonic evolution is
needed in order to produce the basin
sedimentary architecture observed in
the seismic lines.
Acknowledgments
We would like to thank Giovanni
Bertotti (Vrije Universiteit), for his
constructive criticism, for his
supervision of this work and for
inspiring the working team to take
decisions, to formulate questions and
solutions, to be clear and objective. We
thank Fabrizio Pepe (Universita’ di
Palermo) for his help with the
interpretation of the seismic sections.
We thank our families, our
girlfriends/Boyfriend and our friends
for their support during the course of
our studies and the Vrije Universiteit
for giving us the change to conduct this
project.
8. REFERENCES
Antonioli F., Ferranti L., Lambeck K.,
Kershaw S., Verrubbi V., Dai Pra G.
(2006), Late Pleistocene to Holocene
record of changing uplift rates in southern
Calabria and Eastern Sicily (southern Italy,
Central Mediterranean Sea),
Tectonophysics, 422, 23-40
Bailey C., Giorgis S., Coiner L. (2002),
Tectonic inversion and basement
buttressing: an example from the central
Appalachian Blue Ridge province, Journal
of Structural Geology, 24, 925-936
Barone M., Dominici R., Muto F., Critelli
S. (2008), Detrital modes in a late Miocene
wedge-top basin, Northeastern Calabria,
Italy: compositional record of wedge-top
partitioning, Journal of Sedimentary
Research, 78, 693-711
Bordoni P., Valensise G. (1998),
Deformation of the 125ka marine terrace in
Italy:
Tectonic implications, in Coastal
Tectonics, Geol. Soc. Spec. Publ., 146, 71–
110
Brun J.P., Faccenna C. (2008), Exhumation
of high-pressure rocks driven by slab
rollback, Earth and Planetary Science
Letters, 272, 1–7
Cifelli F., Rossetti F., Mattei M. (2007),
The architecture of brittle postorogenic
extension: Results from an integrated
structural and paleomagnetic study in north
Calabria (southern Italy), GSA Bulletin,
119, 221–239
Civello S., Margheriti L. (2004), Toroidal
mantle flow around the Calabrian slab
(Italy) from SKS splitting, Geophysical
research letters, 31
Colella A. (1988), Fault controlled marine
Gilbert-type fan deltas, Geology, 16, 1031-
1034
Cucci, L. (2004), Raised marine terraces in
the Northern Calabrian arc (Southern
Italy): a 600 kyr-long geological record of
regional uplift, Annals of Geophysics, 47
(4), 1391– 1406
Elter P., Grasso M., Parotto M., Vezzani L.
(2003), Structural setting of the Apennine-
Maghrebian thrust belt, Episodes, Vol. 26,
no. 3
Faccenna C., Becker T., Pio Lucente F.,
Jolivet L., Rossetti F. (2001), History of
subduction and back-arc extension in the
Central Mediterranean, Geophys. J. Int.,
145, 809-820
Faccenna C., Piromallo C., Crespo-Blanc
A., Jolivet L., Rossetti F. (2004), Lateral
slab deformation and the origin of the
Western Mediterranean arcs, Tectonics, 23
Faccenna C., Funiciello F., Civetta L.,
D'Antonio M., Moroni M., Piromallo C.,
(2007), Slab disruption, mantle circulation,
and the opening of the Tyrrhenian basins.
In: Cenozoic Volcanism in the

Mediterranean Area, Geological Society of
America Special Paper, 418, 153-169
Ferranti L., Santoro E., Mazzella., Monaco
C., Morelli D. (2009), Active transpression
in the northern Calabria Apennines,
Southern Italy, Tectonophysics, 476, 226-
251
Funiciello F., Faccenna C., Giardini D.
(2004), Role of Lateral Mantle Flow in the
Evolution of Subduction System: Insights
from 3-D Laboratory Experiments.
Geophysical Journal International, 157,
1393-1406
Funiciello F., Moroni M., Piromallo C.,
Faccenna C., Cenedese C, Bui H.A.
(2006), Mapping mantle flow during
retreating subduction: Laboratory models
analyzed
by feature tracking, Journal of Geophysical
Research, 111, B03402.
Funiciello F., Faccenna C., Heuret A.,
Lallemand S., Di Giuseppe E., Becker
T.W., (2008) Trench migration, net
rotation and slab - mantle coupling, Earth
and Planetary Science Letters, 271, 233-
240
Guarnieri P. (2005), Plio-Quaternary
segmentation of the south Tyrrhenian
forearc basin, International Journal of
Earth Sciences, 95, 107–118
Jolivet L., Faccenna C. (2000),
Mediterranean extension and the Africa-
Eurasia collision, Tectonics, 19(6), 1095–
1106
Malinverno A., Ryan W. (1986), Extension
in the Tyrrhenian sea and shortening in the
Apennines as result of arc migration driven
by sinking of the lithosphere, Tectonics, 5,
227-245
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 (Southern Italy), GSA
Bullettin, 114, 1183-1209
Mattei M., Cipollari P., Cosentino D.,
Argentieri A., Rossetti F., Speranza F., Di
Bella L. (2002), The Miocene tectono-
sedimentary evolution of the southern
Tyrrhenian Sea: stratigraphy, structural and
palaeomagnetic data from the on-shore
Amantea basin (Calabrian Arc, Italy),
Basin Research, 14, 147 – 168
Mattei M., Cifelli F., D’Agostino N.
(2007), The evolution of the Calabrian
Arc: Evidence from paleomagnetic and
GPS observations, Earth and Planetary
Science Letters, 263, 259-274
Mellere D., Zecchin M., Perale C. (2005),
Stratigraphy and sedimentology of fault-
controlled backstepping shorefaces, Middle
Pliocene of Crotone Basin, Southern Italy,
Sedimentary Geology, 176, 281-303
Minelli L., Faccenna C. (2010), Evolution
of the Calabrian Accretionary wedge
(Central Mediterranean): Possible impact
of the Messinian salinity crisis, in press
Molin P., Pazzaglia F., Dramis F. (2004),
Geomorphic expression of active tectonics
in a rapidly deforming forearc, Sila Massif,
Calabria, Southern Italy, American Journal
of Science, 304, 559-589
Neri G., Orecchio B., Totaro C., Falcone
G., Presti D. (2009), Subduction Beneath
Southern Italy Close the Ending: Results
from Seismic Tomography, Seismological
Research Letters, 80, 63-70
Olivetti V. (2009), Erosione e
sollevamento nell’Arco Calabro-
Peloritano, Doctoral Thesis, University of
Bologna
Pepe F., Sulli A., Bertotti G., Cella F.
(2010), The architecture and Neogene to
Recent evolution of the W Calabrian
continental margin: an upper plate
perspective to the Ionian subduction
system (Central Mediterranean), in press
Robustelli G., Muto F., Scarciglia F., Spina
V., Critelli S. (2005), Eustatic and tectonic
control on Late Quaternary alluvial fans
along the Tyrrhenian Sea coast of Calabria

(South Italy), Quaternary Science Reviews,
24, 2101-2119
Rossetti F., Faccenna C., Goffé B., Monié
P., Argentieri A., Funiciello R., Mattei M.
(2001), Alpine structural and metamorphic
signature of the Sila Piccola Massif nappe
stack (Calabria, Italy): Insights for the
tectonic evolution of the Calabrian Arc,
Tectonics, 20, 112-133
Rossetti F., Faccenna C., Goffé B., Monié
P., Vignaroli G. (2004), Alpine orogenic P-
T-t-deformation history of the Catena
Costiera area and surrounding regions
(Calabrian Arc, southern Italy): The nappe
edifice of north Calabria revised with
insights on the Tyrrhenian-Apennine
system formation, Tectonics, 23, TC6011,
doi:10.1029/2003TC001560
Santoro E., Mazzella M., Ferranti L.,
Randisi A., Napolitano E., Rittner S.,
Radtke U. (2009), Raised coastal terraces
along the Ionian Sea coast of northern
Calabria,
Italy, suggest space and time variability of
tectonic uplift rates, Quaternary
International, 206, 78–101
Scarciglia F., Le Pera E., Critelli S. (2005),
Weathering and pedogenesis in the Sila
Grande Massif (Calabria, South Italy):
from field scale to micromorphology,
Catena, 61, 1-29
Sorriso Valvo M., Sylvester A. G. (1991),
The relationship between geology and
landforms along a coastal mountain front,
Northern Calabria, Italy, Earth Surface and
Landforms, 18, 257-273
Spina V., Tondi E., Galli P., Mazzoli S.
(2009), Fault propagation in a seismic gap
area (northern Calabria, Italy):
Implications for seismic hazard,
Tansi C., Muto F., Critelli S., Iovine G.
(2007), Neogene-Quaternary strike-slip
tectonics in the central Calabrian Arc
(southern Italy), Journal of Geodynamics,
43, 393-414
Thomson S.N. (1994), Fission track
analysis of the crystalline basement rocks
of the Calabrian Arc, southern Italy:
evidence of Oligo-Miocene late orogenic
extension and erosion, Tectonophysics,
238, 331-352
Tortorici L., Monaco C., Tansi C., Cocina
O. (2004), Recent and active tectonics in
the Calabrian arc (Southern Italy),
Zecchin M., Nalin R., Roda. (2004),
Raised Pleistocene marine terraces of the
Crotone peninsula (Calabria, Southern
Italy): facies analysis and organization of
their deposits, Sedimentary Geology, 172,
165-185
Van Dijk J.P., Bello M., Brancaleoni G.,
Cantarella G., Costa V., Frixa A., Golfetto
F., Merlini S., Riva M., Torricelli S.,
Toscano C., Zerilli A. (2000), A regional
structural model for the northern sector of
the Calabrian Arc (southern Italy),
Tectonophysics, 324, 267–320
Westaway R., Bridgland D. (2007), Late
Cenozoic uplift of Southern Italy deduced
from fluvial and marine sediments:
Coupling between surface processes and
lower crustal flow, Quaternary
International, 175, 86-124
Zecchin M., Massari F., Mellere D.,
Prosser G. (2004), Anatomy and evolution
of a Mediterranean-type fault bounded
basin: the Lower Pliocene of the northern
Crotone Basin (Southern Italy), Basin
Research, 16, 117-143

Thesis_MSc_Ruben_A

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Thesis_MSc_Ruben_A

Similar to Thesis_MSc_Ruben_A (20)

Thesis_MSc_Ruben_A