doi: 10.1111/ter.12082
New insights on diapirism in the Adriatic Sea: the Tremiti salt
structure (Apulia offshore, southeastern Italy)
Vincenzo Festa, Gianvito Teofilo, Marcello Tropeano, Luisa Sabato and Luigi Spalluto
Dipartimento di Scienze della Terra e Geoambientali - via E. Orabona 4, Universit
a degli Studi di Bari “Aldo Moro”, Bari 70125, Italy
ABSTRACT
active today. An ancient extensional SE-dipping fault, cutting
an older Mesozoic low-amplitude anhydritic ridge, played an
important role during salt mobilization, which was promoted
by NW-SE shortening. The diapir grew in the footwall of this
fault, causing its upward propagation. In some places, the
ancient fault served as a preferential channel for the upward
migration of the anhydrites.
D
I
D
R
IA
C
TI
Ad
A
ria
tic
200 km
R
N44°
I
D
P
E
N
N
I
Pla
halo
tfor
m
strukinetic
ctur
Tremiti
es
Islands
Adria
Fig. 2 Gargano
Promontory
Basi tic S
n
E
Apuli
A
A
a
n
P
N
U
E
S
TYRRHENIAN
N40°
SEA
L
I A
S
N42°
Plat
IONIAN
form
ALBANIDES
E
© 2013 John Wiley & Sons Ltd
A
Correspondence: Dr. Vincenzo Festa,
Dipartimento di Scienze della Terra e
Geoambientali - via E. Orabona 4, Universit
a degli Studi di Bari “Aldo Moro”,
Bari 70125, Italy. Tel.: +39 080 5443468;
e-mail: vincenzo.festa@uniba.it
N
A
Triassic to Lower Jurassic evaporites
developed in the peri-Tethyan and
proto-Atlantic areas over epicratonic
platforms (e.g. Courel et al., 2003;
Alves et al., 2006; Hudec and Jackson, 2007). Near and along the
fronts of the Apennines, DinaridesAlbanides and Hellenides orogens
(Mediterranean Sea region), these
evaporites migrated upwards to form
diapirs, mostly during the Neogene,
often inducing sea-floor deformation
in the form of ridges (e.g. Underhill,
1988; Zelilidis et al., 1998; Kamberis
et al., 2000; Kokinou et al., 2005;
Scrocca, 2006; Alves et al., 2007;
Geletti et al., 2008; Kokkalas et al.,
2013). Tectonic shortening associated
with the accretion of the orogens
enhanced salt mobilization within
both the external thrusts area (e.g.
Kokkalas et al., 2013) and the foredeep sensu stricto (i.e. the sector not
involved in thrusting; Scrocca, 2006).
Geletti et al. (2008, and references
therein) highlighted the occurrence of
several diapirs in the central Adriatic
Sea, between the opposite fronts of
the
Apennines
and
Dinarides
(Fig. 1). Here, diapirs are characterized by elongated shapes, mostly
E17°
Introduction
E19°
Terra Nova, 26, 169–178, 2014
E15°
The reinterpretation of public seismic profiles in the Adriatic
offshore of Gargano (Apulia, southern Italy) allowed the
detection of a kilometre-scale salt-anticline, the Tremiti diapir, within the larger Tremiti Structure. This anticline was
generated by diapirism of Upper Triassic anhydrites within a
thick Mesozoic to Quaternary sedimentary succession. Both
internal stratal patterns and shapes of Plio-Quaternary units,
and the occurrence of an angular unconformity between early
Tortonian and Pliocene rocks on the Tremiti Islands, suggest
that halokinesis began during the late Miocene and is still
SEA
Fig. 1 Schematic structural map of the region around the Adriatic Sea (after
Zappaterra, 1990, 1994; modified). In the area not involved in the Apennines and
Dinarides opposite orogens, the Meso-Cenozoic paleogeographic position of the
Adriatic Basin between the Apulian and Adriatic carbonate platforms is shown.
The fronts of the Apennines and Dinarides are according to Scrocca (2006), and
Fantoni and Franciosi (2010), respectively. The halokinetic structures inferred or
hypothesized (e.g. the SW–NE-striking structure along the Tremiti Islands) by
previous studies are also indicated (after Geletti et al., 2008; modified). The inset
indicates the study area.
169
ra, 1990, 1994; Bernoulli, 2001;
Fig. 1). This pelagic domain developed as a consequence of early
Jurassic rifting of an epeiric area
dominated by carbonates (Rhaetian
dolostones and overlying early Jurassic limestones of the Calcare Massiccio Fm, Fig. 3). The epeiric platform
was rooted on Norian anhydrites
and shallow-water limestones and
dolostones (Burano Fm; Foresta
Umbra1 well, Fig. 3), which overlie
Permian continental deposits (Verrucano Fm) draping the Hercynian
basement (Ricchetti et al., 1988). The
Adriatic Basin succession rests on
the Calcare Massiccio Fm and consists mainly of Jurassic to late Miocene
pelagic
limestones;
thin
Messinian evaporites separate this
succession
from
the overlying
Geological setting
During the Mesozoic, in the Adria
Plate (sensu Channell et al., 1979), a
narrow pelagic basin (the Adriatic
Basin), flanked by carbonate platforms (Apulian, to the SW, and
Adriatic, to the NE), occupied
roughly the same position as the
present-day Adriatic Sea (Zappater-
Famoso 1
42°31’57”
B4
26
Eterno 1
50
0
6
B4
27
BR
2
26
5
3
BR
26
4
B
BR R26
26 0
1
BR
16
8-
21
M13
B4
1000
Tremiti
Islands
500
500
B4
15°06’13”
42
BR
B4
Lesina
Marina
16
MESOZOIC
BASINAL
DOMAIN
9-
30
B4
41
ME
32
SO
MESOZOIC
PLATFORM
Peschici 1
ZO
IC
Fig. 7
16°03’26”
5a
28
g.
10 km
5b
Fig. 4
Fi
N
16
g.
26
BR
Fi
BR
g.
00
Fi
15
8-
BR
10
12
7
1000
26
170
lead to different interpretations (e.g.
Finetti and Del Ben, 2005; Scisciani
and Calamita, 2009), particular
attention has been paid to those typical pre- to post-halokinesis geometries and terminations of the
reflectors within the host-rock of a
salt-diapir (e.g. Pascucci et al., 1999;
Alves et al., 2002, 2009; Rowan
et al., 2003; Stewart, 2007).
BR
NW–SE and secondly, NE–SW
trending. Geletti et al. (2008) also
hypothesized that the NE–SW-striking ridge, whose culmination forms
the Tremiti Islands, could represent a
halokinesis structure. The ridge,
about 15 km north of Gargano
(Apulia, southeastern Italy; Figs 1
and 2), corresponds to the Tremiti
Structure of Andre and Doulcet
(1991).
Several different interpretations
based on local seismicity and/or
seismic profiles and/or regional geodynamic modelling have been suggested for the origin of the Tremiti
Structure. It has been suggested to
be a pushed-up ridge, accommodating deformation occurring along
faults of regional extent characterized
by either E–W right-lateral kinematics (Mele et al., 1990; Argnani et al.,
1993; Favali et al., 1993; Doglioni
et al., 1994; Gambini and Tozzi,
1996) or NE–SW left strike-slip
movement (Finetti and Del Ben,
2005) or undefined kinematics leading to a compressional or transpressional
setting
(Scisciani
and
Calamita, 2009).
The diapiric origin hypothesized by
Geletti et al. (2008) can be supported
by comparing sea-floor deformation
along the Tremiti Structure with that
induced by Plio-Quaternary diapirism
of the Triassic anhydrites in the subsurface of the Adriatic Sea (Scrocca,
2006; Nicolai and Gambini, 2007; Geletti et al., 2008; Grandic and Kolbah,
2009). In addition, a few kilometres
south of the Tremiti Islands, around
Lesina Marina village (Fig. 2), the
cropping out of exotic gypsum rocks
that rose up from the Triassic anhydrite source (Cotecchia and Canitano,
1954; Bigazzi et al., 1996) could represent further evidence supporting the
hypothesized diapiric origin for the
Tremiti Structure.
To verify this hypothesis, the seismic reflection profile M13 of the
CROP Project (Scrocca et al., 2003),
and both free exploration wells and
seismic reflection profiles of the
ViDEPI Project (2012; Fig. 2) dating
back to the 1980–1990s, were interpreted. The profiles of the ViDEPI
Project have been scaled to make
times and distances consistent with
the M13 CROP Project line. Owing
to the low quality of these old, nonmigrated seismic profiles, which can
SHE
LF
41°47’07”
MARGIN
Foresta
Umbra 1
Fig. 2 Map of the study area around the Tremiti Islands (after Google Earth,
2013; modified). White contour lines represent the isobaths of the base of the Pliocene deposits (after Andre and Doulcet, 1991; modified); the Tremiti Structure is
the narrow area where the base-Pliocene depth abruptly decreases. Analysed wells
(shown in Fig. 3) and the grid of the studied seismic profiles are indicated. Thicker
orange lines show the portions of the interpreted seismic profiles M13, BR169-32,
BR168-21 and B426, shown in Figs 4, 5a,b and 6, respectively.
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Diapirism in the Adriatic Sea: the Tremiti salt structure • V. Festa et al.
Terra Nova, Vol 26, No. 3, 169–178
.............................................................................................................................................................
Foresta Umbra 1
Peschici 1
0m
(–160 m)
0m
(55 m)
Aptian-Albian
Marne a Fucoidi
Messinian
Gessoso-
Tortonian
Schlier
Early Cretaceous
Scaglia Cinerea
Messin.
C
Cenomanianmiddle Eocene
Thickness: variable,
up to 2600 m
Aptian-Albian
ThitonianBarremian
Scaglia Calcarea
Marne a Fucoidi
Maiolica
Dogger Malm
Calcari ad Aptici
Late Lias
Rosso
Ammonitico
Middle Lias
Top of
Calcare Massiccio Fm
Corniola
Gessoso-
? Serrav.Torton.
Schlier
Aquit.Langh.
Oligoc.
Bisciaro
Scaglia Cinerea
Late CretaceousEocene
Vp = 4100 m/s
Calcari ad Aptici
Early-Middle Jurassic
Late
Eocenemiddle
Oligocene
Middle Late
Jurassic Jurassic
Base of Pliocene
Maiolica
Early
Jurassic
Thickness: variable,
up to 1400 m
Plio-Quaternary
D
Plio-Quaternary
Vp = 1800 m/s
0m
(809 m)
Ripe Rosse Fm
Calcari ad Aptici
equiv. in slope facies
Eterno 1
0m
(–143 m)
1275 m
Persistent shallow-water conditions through the Early-Middle Jurassic
Famoso 1
Late
Jurassic
Seismostratigraphic units
Scaglia Calcarea
Marne a Fucoidi
Maiolica
Dogger Malm
Calcari ad Aptici
Late Lias
Rosso Ammonitico
Corniola
Middle Lias
Early Lias
Calcare Massiccio Fm
m
900
2270 m
600
Thickness: variable,
up to 2500 m
Rhaetian
Vp = 5900 m/s
B
Early Lias
Calcare Massiccio Fm
300
3126 m
Late Triassic
0
Top of
Triassic anhydrites
A
Cherty limestones
Marly limestones and marls
Dolostones
Limestones
Anhydrites
Burano Fm
Lithology
4303 m
Norian
3290 m
Vp = 6400 m/s
5912 m
Fig. 3 Lithostratigraphic correlation between exploration wells drilled in the Adriatic offshore, i.e. Famoso 1 and Eterno 1,
and in the Gargano onshore, i.e. Peschici 1 and Foresta Umbra 1 (see Fig. 2 for location). Lithostratigraphy of the Gargano
wells is derived from the original data of the ViDEPI Project (2012) modified after Bosellini et al. (1993, 2000). Seismostratigraphic units and their maximum thicknesses computed using interval velocities (Vp) are indicated in the left part. Vp of Unit
A, after Geletti et al. (2008); average Vp of Units B, C and D, according to Bally et al. (1986). The correlation between seismostratigraphic and lithostratigraphic units is also shown.
© 2013 John Wiley & Sons Ltd
171
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V. Festa et al. • Diapirism in the Adriatic Sea: the Tremiti salt structure
............................................................................................................................................................
Terra Nova, Vol 26, No. 3, 169–178
Plio-Pleistocene foreland basin clays
(Santantonio et al., 2013; Famoso1
and Eterno1 wells, Fig. 3).
Seismic stratigraphy
Four main seismostratigraphic units
(A–D, from the bottom; Fig. 3) were
identified in the studied area by
reviewing seismic- and well-data in
accordance with the most recent literature (e.g. Santantonio et al., 2013).
Unit A, exhibiting a semi-transparent seismic facies topped by a high
amplitude reflector (e.g. Fig. 4), is
represented by the anhydritic portion
of the Burano Fm.
Unit B, topped by a strong reflector, exhibits discontinuous and
poorly defined reflectors (Figs 4, 5a,b
and 6), and consists of Burano Fm
limestones and dolostones, Rhaetian
dolostones and Calcare Massiccio
Fm limestones (Fig. 3).
Unit C groups middle Lias to
Messinian lithostratigraphic units
(Famoso 1 and Eterno 1 wells,
Fig. 3) corresponding to the Adriatic
Basin succession. It shows welldefined,
continuous,
subparallel
reflectors and is topped by strong
reflectors of the Gessoso-Solfifera
Fm (Figs 4, 5a,b and 6). In the Tremiti Islands, the top of the unit crops
out, in the form of an angular
unconformity between tilted Palaeocene, Eocene and Miocene (Langhian
to early Tortonian) rocks below and
thin Plio-Pleistocene deposits above
(Cremonini et al.,1971; Andriani
et al., 2005; Brozzetti et al., 2006;
Miccadei et al., 2011).
Finally, Unit D consists of PlioQuaternary emipelagites (Famoso 1,
Eterno 1 wells, Fig. 3), and is characterized by some continuous reflectors, and, locally, semi-transparent
seismic facies (Figs 4, 5a,b and 6).
and 5a,b). Due to the relatively high
Vp value of the anhydrites, the
reflections related to the interbedded
dolostones are affected by velocity
pull-up phenomena within the diapir.
The top of the diapir stands at c.
1.8 s in seismic profile M13 (Fig. 4),
and between c. 0.4 and 0.8 s in the
profiles BR168-21 and BR169-32
(Fig. 5a,b). Considering the Vp value
of the overlying sediments, the roof
is at a minimum depth of c. 750 m
from the sea bottom. Therefore, the
diapir has risen up to c. 3750 m from
the Triassic anhydrite source.
On the flanks of the diapir, reflectors of Unit B, which has a nearly
constant thickness, and Unit A are
geometrically concordant. In contrast, the overlying units C and D
exhibit variable thickness. Unit C is
definitely thinner above the diapir,
while an abrupt increase in thickness
is observed laterally, especially on the
eastern and southeastern sides (Figs 4
and 5a,b). A local thickening of this
sidering the interval velocities (Vp) of
the overlying sedimentary rocks, a
depth of ca. 4500 m has been calculated for this high amplitude reflector.
Along the Tremiti Structure
(Figs 4 and 5a,b), seismic wave diffractions, reflected refractions and
velocity
distortion
phenomena
strongly suggest halokinesis of the
Triassic anhydrites. In addition, and
as shown on seismic profile M13, the
same seismic record may result from
a fault located above the steeply
inclined eastern flank of a halokinesis
structure, i.e. the Tremiti diapir
(Fig. 4). A chaotic and poorly
defined seismic signal typically characterizes the diapir, while the reflectors of the wall-rock appear
generally continuous and better
developed. Often, the reflected refractions, in association with the steeply
inclined flanks of the diapir, can be
observed crosscutting the primary
reflections of the host Unit B and the
lowermost part of Unit C (Figs 4
BR169-32
B428
B430
0
1
2
3
4
0
1
5 km
Unit D
Unit C
Seismic interpretation of the
Tremiti Structure
The interpretation of seismic lines
along the Tremiti Structure required
first the identification of the top of
Unit A in poorly deformed areas. In
agreement with the literature (Finetti
and Del Ben, 2005; Geletti et al.,
2008; Scisciani and Calamita, 2009),
the top of Unit A around the Tremiti
Structure has been located at c. 3.5 s
in seismic profile M13 (Fig. 4). Con172
2
Salt
3
diapir
Unit B
Unit A - anhydrites
4
s
TWT
W-E
Fig. 4 Uninterpreted (above) and interpreted (below) non-migrated and multi-channel stacked seismic profile M13 (see Fig. 2 for location).
© 2013 John Wiley & Sons Ltd
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Diapirism in the Adriatic Sea: the Tremiti salt structure • V. Festa et al.
Terra Nova, Vol 26, No. 3, 169–178
.............................................................................................................................................................
M13
B428
BR168-10
0
(a)
1
2
5 km
0
Unit D
Salt
1
diapir
Unit C
2
Unit B
s
TWT
NW - SE
BR127
BR168-10
0
(b)
Unit D
1
Unit C
Unit B
2
Salt
diapir
5 km
s
TWT
NW - SE
Fig. 5 (a) Uninterpreted (above) and interpreted (below) non-migrated and multichannel stacked seismic profile BR169-32 (see Fig. 2 for location). (b) Uninterpreted (left) and interpreted (right) non-migrated and multi-channel stacked seismic
profile BR168-21 (see Fig. 2 for location).
unit can be appreciated in the western
sector of seismic profile M13, i.e. on
the hangingwalls of synsedimentary
faults showing a dip-slip component
(Fig. 4). These faults belong to a system of NE-dipping extensional faults
© 2013 John Wiley & Sons Ltd
(Fig. 6), which determined thickness
variations in the lower part of Unit C
(Figs 4 and 6) and likely of Unit B
(Fig. 6) during the Mesozoic extensional stage linked to the Jurassic rifting. The abrupt increase in thickness
observed on the eastern side of the
Tremiti Structure along seismic profile M13 (Fig. 4) is an additional evidence of extensional tectonics.
Furthermore, a low-amplitude ridge
structure, involving the NE-dipping
faults (Fig. 6), developed with a NW–
SE trend (Fig. 7).
On the flanks of the Tremiti Structure, reflectors show that gentle drag
folds involve both Unit B (Fig. 5a,b)
and the lower part of Unit C (Figs 4
and 5a,b), which were upturned by
rising anhydrite. From the sides to
the roof of the diapir, the geometries
of reflectors within the wall-rock are
compatible with an open, asymmetric
anticline affecting both Unit B and
Unit C (Figs 4 and 5a,b), which is
thinner in its uppermost portion (e.g.
Fig. 5a). As shown on seismic profile
M13 (Fig. 4), compressive minor
faults have been recognized in the
eastern side of the diapir. In Unit D,
internal unconformities, and reflectors recording upturned strata, are
locally observed. Furthermore, the
unit exhibits a decrease in thickness
approaching the anticline, whose
crest is truncated by an erosional
surface (Figs 4 and 5a,b). The latter
corresponds to an unconformity
below the apparently undisturbed
Plio-Quaternary sediments.
According to well-known shape
classifications of salt structures (Jackson and Talbot, 1991; Stewart, 2007;
Guerra and Underhill, 2012), a saltanticline-type geometry may be
inferred from the seismic profiles of
the Tremiti diapir, which is c. 7–
8 km wide (Fig. 5a,b). In map view,
the salt-anticline is developed for c.
30 km and its axial-plane trace is
arched with a gentle concavity
towards the NW; northwards, it
strikes NNE–SSW, whereas southwards, it curves towards an ENE–
WSW trend (Fig. 7). A strong
asymmetry of this salt-anticline can
be appreciated in seismic profile M13
(Fig. 4), i.e. along the intermediate
part of the NE–SW-striking Tremiti
diapir (Fig. 7).
Discussion: age and mode of
halokinesis
Two stages of halokinesis of the Triassic anhydrites can be recognized in
the Tremiti Islands area.
173
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V. Festa et al. • Diapirism in the Adriatic Sea: the Tremiti salt structure
............................................................................................................................................................
Terra Nova, Vol 26, No. 3, 169–178
0
1
2
3
4
5 km
Unit D
1
Unit C
2
Unit B
3
Unit A - anhydrites
4
s
TWT
SW - NE
Fig. 6 (a) Uninterpreted (above) and interpreted (below) non-migrated and multichannel stacked seismic profile B426 (see Fig. 2 for location).
The older one is characterized by a
low-amplitude
ridge
structure
(Fig. 6), striking parallel to the
ancient,
extensional
NE-dipping
faults (Figs 6 and 7), and related to
the early Jurassic rifting (Santantonio
et al., 2013). The ridge is bordered to
the NE by the fault that records the
maximum
dip-slip
displacement
(Fig. 6). In accordance with several
models of diapirism in extensional
tectonic settings (e.g. Vandeville and
Jackson, 1992; Schultz-Ela and Jackson, 1996; Rowan et al., 1999; Stewart, 2007; Guerra and Underhill,
2012), this kind of fault could have
promoted migration of the salt
towards the hangingwall. Here, the
low-amplitude ridge likely developed
in Unit B during the deposition of
174
Unit C, namely during the regional
subsidence that followed the main
fault displacement (Fig. 8).
The younger halokinesis stage
began during the late Miocene. The
internal unconformities in Unit D
and its thinning approaching the Tremiti diapir (e.g. Fig. 4) indicate that
the salt-anticline grew during the
Plio-Quaternary due to the upward
movement of the Triassic anhydrites
(Fig. 9). However, on the Tremiti
Islands, the angular unconformity
separating early Tortonian deformed
rocks from less-deformed Pliocene
deposits indicates that this halokinesis
deformation began before the Pliocene. Moreover, the diapirism seems
to be still active as, on high-resolution
seismic profiles, deposits of the post-
last glacial interval show weak deformations that also involve the sea floor
(Ridente and Trincardi, 2006).
Late Paleogene–Neogene halokinesis structures found in the Adriatic
Sea, north of the Tremiti Islands, by
Geletti et al. (2008, and references
therein; Fig. 1) could have been
enhanced by horizontal shortening
linked to either the Apenninic or Dinaric orogenesis (Scrocca, 2006; Grandic and Kolbah, 2009). In such a
setting, the axes of salt-anticlines
strike perpendicular to the regional
shortening direction, as demonstrated
also by Jahani et al. (2009) in the Persian Gulf (i.e. the foreland basin of
the Zagros orogen). In the Adriatic
Sea, these NW–SE-striking salt-anticlines developed mainly on top of
pre-existing NW–SE-striking diapirs,
elongated like the old low-amplitude
salt ridge in the Tremiti area.
In contrast, despite the presence of
the old salt ridge, the axis of the
younger Tremiti salt-anticline strikes
roughly NE–SW, and is perpendicular to the Apennines front. This
geometry is coherent with NW–SE
shortening (Fig. 7), whose occurrence
in the area could be related to the
presence of an active tectonic boundary deduced by seismicity and separating the Adriatic into north and
south blocks with different velocity
motions (Oldow et al., 2002). In
addition, this shortening is in accordance with the local component of
the E-W right-lateral simple shear
inferred by several authors (Mele
et al., 1990; Argnani et al., 1993; Favali et al., 1993; Doglioni et al.,
1994; Gambini and Tozzi, 1996).
The mode of emplacement of the
Tremiti diapir, reconstructed in
accordance with the NW–SE shortening direction (Fig. 9), is mainly
constrained by the interpretation of
seismic profile M13 (Fig. 4). The
emplacement needed a NE–SW-oriented zone of weakness for the
upward migration of the anhydrites
(Figs 7 and 9). The abrupt increase
in thickness of Unit C on the southeastern side of the Tremiti diapir
(Figs 4 and 5a,b) strongly supports
the presence of an ancient NE–SWstriking extensional fault (Figs 7 and
9). This inferred fault strikes subparallel to the normal faults accompanying the widespread NW–SE dip-slip
faults activated during the Jurassic–
© 2013 John Wiley & Sons Ltd
13653121, 2014, 3, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/ter.12082 by Universita Di Perugia, Wiley Online Library on [21/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License
Diapirism in the Adriatic Sea: the Tremiti salt structure • V. Festa et al.
Terra Nova, Vol 26, No. 3, 169–178
.............................................................................................................................................................
42°26’09”
26
de
. 9 litu
Fig amp ge
- rid
lowitic
oic dr
oz hy
es an
M
B4
16
8-
Mesozoic
dip-slip faults
10 km
21
Anticline
Salt
axis
anticline,
i.e. Tremiti
diapir
BR
9-
32
Fi
Tremiti
Islands
Fi
g.
g.
5a
.9
Fig
15°13’24”
Fi
g.
Tremiti
ridge
5b
Fault
favouring the
ascent of the
Tremiti diapir
M13
Fig. 4
16
42°02’38”
15°58’49”
8
BR
Fi
g.
Fi
g.
6
N
Sh
or
te
ni
ng
Tremiti
diapir
10
Fig. 7 Structural sketch map of the Tremiti Islands area, where the old Mesozoic
anhydritic low-amplitude ridge and the younger Neogene Tremiti diapir (roughly
corresponding to the Tremiti ridge) are emphasized in grey. Note the geometric
relationships between the dip-slip Mesozoic faults and the coeval salt low-amplitude ridge, and between the Tremiti diapir and the fault that favoured its rising up.
Cretaceous
s.l.
Unit C
Cretaceous (Festa, 2003; Santantonio
et al., 2013). Much later, during the
NW-SE shortening, the anhydrites
migrated in the footwall of the fault,
beneath Unit B (Fig. 9). Above the
southeastern flank of the diapir, the
growth of the anhydritic body determined an upward propagation, with
a dip-slip displacement, of the
ancient fault (Fig. 9). Drape upbending of Units B and C occurred, and
an asymmetric salt-anticline developed (Figs 4 and 9). In addition, the
NW–SE shortening may have led to
the arching of this fault, which has a
gentle concavity towards the NW
(Fig. 7).
Towards the north-east and southwest terminations of the salt-anticline
(Fig. 7), the anhydrites simply used
the weakened zone of the ancient
fault as a preferential channel for
their upward migration through Unit
B (e.g. Fig. 10). Upward dragging of
Unit B, piercing of the lower part of
Unit C, and folding of the intermediate and upper parts of this unit also
occurred (Fig. 5a,b). In addition, in
the south-west termination of the
salt-anticline, an inversion of the
ancient dip-slip fault, which occurred
during piercing of the anhydrites,
would explain both the highest position of Unit C, and the thinness of
Unit D in the hangingwall, compared
with the footwall (Fig. 10).
Concluding remarks
Early Jurassic
s.l.
Unit C
Unit B
Unit A
SW
5 km
NE
Fig. 8 2D frames summarizing the mode of emplacement of the low-amplitude
ridge, from early Jurassic to Cretaceous. Reconstruction is based on the interpretation of the seismic reflection profile in Fig. 6, and is perpendicular to the elongation of the Mesozoic anhydritic low-amplitude ridge (see Fig. 7).
© 2013 John Wiley & Sons Ltd
The occurrence of the Tremiti ridge
and its outstanding size are the
result of late Miocene to present-day
salt tectonics overprinting a Mesozoic low-amplitude salt ridge. A
halokinesis structure, the Tremiti
diapir, made up of Triassic anhydrites, is located beneath this ridge.
The Tremiti diapir forms an anticline whose axis is approximately
perpendicular to both the elongations of most of the Neogene diapirs, and the Apenninic and Dinaric
fronts, which strike NW–SE in the
sector of the Adriatic Sea north of
Gargano Promontory. The development of this diapir required NW–SE
shortening, and occurred along a
pre-existing SE-dipping extensional
fault, whose origin dates back to the
Jurassic–Cretaceous. In its central
part, the diapir was emplaced in the
footwall of this fault. Both shorten175
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V. Festa et al. • Diapirism in the Adriatic Sea: the Tremiti salt structure
............................................................................................................................................................
Terra Nova, Vol 26, No. 3, 169–178
axes strike NW–SE, i.e. perpendicular to the shortening direction due to
the opposite propagation of the
Apenninic and Dinaric fronts. In
contrast, NW–SE shortening could
have locally promoted both salt
mobilization and NE–SW-elongated
salt-anticlines representing the other
set. These halokinesis structures
developed parallel to the Tremiti diapir, likely along Jurassic–Cretaceous
faults.
Present-day
s.l.
Pleistocene
s.l.
Acknowledgements
This study was supported by “Convenzione tra Autorita di Bacino della Puglia e
Dipartimento Geomineralogico dell’Universita degli Studi di Bari per studi
petrografici e mineralogici, oltre che
geologico-strutturali, nell’area di Lesina
Marina (FG) – 2009” research funds, to
V. Festa. We are grateful to T. Alves,
L. Ferranti and an anonymous reviewer,
whose suggestions helped us to improve
the
manuscript.
Discussions
with
D. Scrocca, J. Underhill and S. Nardon
were very useful.
Pliocene
s.l.
Unit D
References
Late Miocene
s.l.
Unit C
Unit B
Unit A
NW
10 km
SE
Fig. 9 2D frames summarizing the mode of emplacement of the Tremiti diapir,
from late Miocene to present-day. Reconstruction is based on the interpretation of
the seismic profile M13 (Fig. 4), and is subparallel to the elongation of the old
Mesozoic anhydritic low-amplitude ridge (see Fig. 7).
ing and upward growth of the diapir
were able to uplift the entire footwall. As a consequence, upward
propagation of the fault with dipslip kinematics occurred. Towards
the terminations of the diapir, the
fault, which was locally reactivated
with reverse kinematics, represented
a path for the upward migration
and squeezing of the anhydrites,
which pierced and folded the above
wall-rock.
These results could represent an
interpretive key for the scattered
176
halokinetic structures occurring in
the Adriatic Basin, north of the
Tremiti Islands. NW-SE-elongated
diapirs originally developed during
the Mesozoic in the form of lowamplitude ridges, whose geometric
features were driven by the activity
of extensional faults. During the
Neogene, two sets of diapirs with
opposite elongations developed. The
most representative set consists of
halokinesis structures that grew on
top of, and parallel to, the pre-existing low-amplitude diapirs. Their fold
Alves, T.M., Gawthorpe, R.L., Hunt,
D.W. and Monteiro, J.H., 2002.
Jurassic tectono-sedimentary evolution
of the Northern Lusitanian Basin
(offshore Portugal). Mar. Petrol. Geol.,
19, 727–754.
Alves, T.M., Moita, C., Sandnes, F.,
Cunha, T., Monteiro, J.H. and
Pinheiro, L.M., 2006. Mesozoic–
Cenozoic evolution of North Atlantic
continental-slope basins: the Peniche
basin, western Iberian margin. AAPG
Bull., 90, 31–60.
Alves, T.M., Lykousis, V., Sakellariou,
D., Alexandri, S. and Nomikou, P.,
2007. Constraining the origin and
evolution of confined turbidite systems:
southern Cretan margin, Eastern
Mediterranean Sea (34°30–36°N). GeoMar. Lett., 27, 41–61.
Alves, T.M., Cartwright, J. and Davies,
R.J., 2009. Faulting of salt-withdrawal
basins during early halokinesis: effects
on the Paleogene Rio Doce Canyon
system (Espırito Santo Basin, Brazil).
AAPG Bull., 93, 617–652.
Andre, P. and Doulcet, A., 1991. Rospo
mare field – Italy, Apulian Platform,
Adriatic Sea. In: Treatise of Petroleum
Geology, Atlas of Oil and Gas Fields,
Stratigraphic Traps II, (N.H. Foster
and E.A. Beaumont, eds.), pp.29–54.
AAPG, Tulsa.
Andriani, G. F., Walsh, N. and
Pagliarulo, R., 2005. The influence of
© 2013 John Wiley & Sons Ltd
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Diapirism in the Adriatic Sea: the Tremiti salt structure • V. Festa et al.
Terra Nova, Vol 26, No. 3, 169–178
.............................................................................................................................................................
s.l.
Unit D
Unit C
Unit B
Unit A
NW
5 km
SE
Fig. 10 2D schematic interpretation of the seismic profile BR169-32 (Fig. 5a),
crossing the southwestern termination of the Tremiti diapir (see Fig. 7 for location). The path taken during upward migration and squeezing of the anhydrites is
indicated by the blue arrows, near the fault plane. Note in Unit C, piercing and
folding due to the Tremiti diapir. The inversion of the originally dip-slip fault is
indicated by the red arrow. The highest position of Unit C, and the thinness of
Unit D in the hangingwall, compared with the footwall, can be appreciated.
the geological setting on the
morphogenetic evolution of the Tremiti
Archipelago (Apulia, Southeastern
Italy). Nat. Hazard Earth Sys., 5, 29–
41.
Argnani, A., Favali, P., Frugoni, F.,
Gasperini, M., Ligi, M., Marani., M.,
Mattietti, G. and Mele, G., 1993.
Foreland deformational pattern in the
Southern Adriatic Sea. Ann. Geofis., 36,
229–247.
Bally, A.W., Burbi, L., Cooper, C. and
Ghelardoni, R., 1986. Balanced sections
and seismic reflection profiles across the
Central Apennines. Mem. Soc. Geol. It.,
35, 257–310.
Bernoulli, D., 2001. Mesozoic-Tertiary
carbonate platforms, slopes and basins
of the external Apennines and Sicily.
In: Anatomy of an Orogen: The
Apennines and Adjacent Mediterranean
Basins (G.B. Vai and I.P. Martini, eds),
pp. 307–325. Springer, Amsterdam.
Bigazzi, G., Laurenzi, M.A., Principe, C.
and Brocchini, D., 1996. New
geochronological data on igneous rocks
and evaporites of the Pietre Nere Point
(Gargano peninsula, southern Italy).
Boll. Soc. Geol. It., 115, 439–448.
Bosellini, A., Neri, C. and Luciani, V.,
1993. Guida ai carbonati cretaceoeocenici di scarpata e di bacino del
Gargano (Italia meridionale). Ann.
Univ. Ferrara (N.S.), Sez. Sc. Terra, 4,
81.
© 2013 John Wiley & Sons Ltd
Bosellini, A., Morsilli, M. and Neri, C.,
2000. The eastern margin of the Apulian
Platform: the Gargano transect. Guide
book, Pragma Media, Ferrara, 46pp.
Brozzetti, F., D’Amato, D. and Pace, B.,
2006. Complessita delle deformazioni
neogeniche nell’avampaese adriatico:
nuovi dati strutturali dalle Isole
Tremiti. Rend. Soc. Geol. Ital., Nuova
Serie, 2, 94–97.
Channell, J.E.T., D’Argenio, B. and
Horvath, F., 1979. Adria, the African
Promontory in Mesozoic
Mediterranean Palaeogeography. EarthSci. Rev., 15, 213–292.
Cotecchia, V. and Canitano, A., 1954.
Sull’affioramento delle “Pietre Nere” al
lago di Lesina. Boll. Soc. Geol. It., 73,
3–18.
Courel, L., Ait Salem, H., Benaouiss, N.,
Et-Touhami, M., Fekirine, B., Oujidi,
M., Soussi, M. and Tourani, A., 2003.
Mid-Triassic to Early Liassic clastic/
evaporitic deposits over the Maghreb
Platform. Palaeogeogr. Palaeoclimatol.
Palaeoecol., 196, 157–176.
Cremonini, G., Elmi, C. and Selli, R.,
1971. Note illustrative della Carta
Geologica d’Italia, scala 1: 100.000,
Foglio 156 “S. Marco in Lamis”.
Servizio Geologico d’Italia, Roma, 66
pp.
Doglioni, C., Mongelli, F. and Pieri, P.,
1994. The Puglia uplift (SE Italy): an
anomaly in the foreland of the
Apenninic subduction due to buckling
of a thick continental lithosphere.
Tectonics, 13, 1039–1321.
Fantoni, R. and Franciosi, R., 2010.
Tectono-sedimentary setting of Po
Plain and Adriatic foreland. Rend. Fis.
Acc. Lincei, 21(Suppl. 1), 197–209.
Favali, P., Funiciello, R., Mattietti, G.,
Mele, G. and Salvini, F., 1993. An
active margin across the Adriatic Sea
(central Mediterranean Sea).
Tectonophysics, 219, 109–117.
Festa, V., 2003. Cretaceous structural
features of the Murge area (Apulian
Foreland, Southern Italy). Eclogae
Geol. Helv., 96, 11–22.
Finetti, I.R. and Del Ben, A., 2005.
Crustal tectono-stratigraphic setting of
the Adriatic sea from new CROP
seismic data. In: CROP PROJECT:
Deep Seismic Exploration of the Central
Mediterranean and Italy (I.R. Finetti,
ed.), pp. 519–547. Elsevier, Amsterdam.
Gambini, R. and Tozzi, M., 1996.
Tertiary geodynamic evolution of the
Southern Adria microplate. Terra
Nova, 8, 593–602.
Geletti, R., Del Ben, A., Busetti, M.,
Ramella, R. and Volpi, V., 2008. Gas
seeps linked to salt structures in the
Central Adriatic Sea. Basin Res., 20,
473–487.
Google Earth, 2013. Google Inc.
(available from http://www.google.com/
earth/)
Grandic, S. and Kolbah, S., 2009. New
commercial oil discovery at Rovesti
Structure in South Adriatic and its
importance for Croatian part of
Adriatic Basin. Nafta, 60, 68–82.
Guerra, M.C.M. and Underhill, J.R.,
2012. Role of halokinesis in controlling
structural styles and sediment dispersal
in the Santos Basin, offshore Brazil. In:
Salt Tectonics, Sediments and
Prospectivity (G.I. Alsop, S.G. Archer,
A.J. Hartley, N.T. Grant and R.
Hodgkinson, eds), Geol. Soc. London
Spec. Publ., 363, 175–206.
Hudec, R. and Jackson, M.P.A., 2007.
Terra infirma: understanding salt
tectonics. Earth-Sci. Rev., 82, 1–28.
Jackson, M.P.A. and Talbot, C.J., 1991.
A Glossary of Salt Tectonics.
Geological Circular, 91-4. The
University of Texas at Austin, Bureau
of Economic Geology, Austin. 44 pp.
Jahani, S., Callot, J.-P., Letouzey, J. and
Frizon de Lamotte, D., 2009. The
eastern termination of the Zagros Foldand-Thrust Belt, Iran: structures,
evolution, and relationships between
salt plugs, folding, and faulting.
Tectonics, 28, TC6004.
Kamberis, E., Sotiropoulos, S.,
Aximniotou, O., Tsaila-Monopoli, S.
and Ioakim, C., 2000. Late Cenozoic
deformation of the Gavrovo and
177
13653121, 2014, 3, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/ter.12082 by Universita Di Perugia, Wiley Online Library on [21/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License
V. Festa et al. • Diapirism in the Adriatic Sea: the Tremiti salt structure
............................................................................................................................................................
Terra Nova, Vol 26, No. 3, 169–178
Ionian zones in NW Peloponnesos
(Western Greece). Ann. Geofis., 43,
905–919.
Kokinou, E., Kamberis, E., Vafidis, A.,
Monopolis., D., Ananiadis, G. and
Zelilidis, A., 2005. Deep seismic
reflection data from offshore western
Greece: a new crustal model for the
Ionian Sea. J. Petrol. Geol., 28,
185–202.
Kokkalas, S., Kamberis, E., Xypolias, P.,
Sotiropoulos, S. and Koukouvelas, I.,
2013. Coexistence of thin- and thickskinned tectonics in Zakynthos area
(western Greece): insights from seismic
sections and regional seismicity.
Tectonophysics, 597–598, 73–84.
Mele, G., Mattietti, G. and Favali, P.,
1990. Sismotettonica dell’area adriatica:
interpretazione di dati sismologici
recenti. Mem. Soc. Geol. It., 45, 233–
241.
Miccadei, E., Mascioli, F. and Piacentini,
T., 2011. Quaternary geomorphological
evolution of the Tremiti Islands
(Puglia, Italy). Quatern. Int., 233, 3–15.
Nicolai, C. and Gambini, R., 2007.
Structural architecture of the Adria
platform-and-basin system. Boll. Soc.
Geol. It., Suppl. 7, 21–37.
Oldow, J.S., Ferranti, L., Lewis, D.S.,
Campbell, J.K., D’Argenio, B.,
Catalano, R., Pappone, G.,
Carmignani, L., Conti, P. and Aiken,
C.L.V, 2002. Active fragmentation of
Adria, the north African promontory,
central Mediterranean orogen. Geology,
30, 779–782.
Pascucci, V., Gibling, M.R. and
Williamson, M.A., 1999. Seismic
stratigraphic analysis of Carboniferous
strata on the Burin Platform, offshore
Eastern Canada. Bull. Can. Petrol.
Geol., 47, 298–316.
178
Ricchetti, G., Ciaranfi, N., Luperto Sinni,
E., Mongelli, F. and Pieri, P., 1988.
Geodinamica ed evoluzione sedimentaria
e tettonica dell’Avampaese Apulo. Mem.
Soc. Geol. It., 41, 57–82.
Ridente, D. and Trincardi, F., 2006.
Active foreland deformation evidenced
by shallow folds and faults affecting
late Quaternary shelf-slope deposits
(Adriatic Sea, Italy). Basin Res., 18,
171–188.
Rowan, M.G., Jackson, M.P.A. and
Trudgill, B.D., 1999. Salt-Related Fault
Families and Fault Welds in the
Northern Gulf of Mexico. AAPG Bull.,
83, 1454–1484.
Rowan, M.G., Lawton, T.F., Giles, K.A.
and Ratliff, R.A., 2003. Near-salt
deformation in La Popa basin, Mexico,
and the northern Gulf of Mexico: a
general model for passive diapirism.
AAPG Bull., 87, 733–756.
Santantonio, M., Scrocca, D. and
Lipparini, L., 2013. The OmbrinaRospo Plateau (Apulian Platform):
evolution of a Carbonate Platform and
its Margins during the Jurassic and
Cretaceous. Mar. Petrol. Geol., 42, 4–
29.
Schultz-Ela, D.D. and Jackson, M.P.A.,
1996. Relation of Subsalt Structures to
Suprasalt Structures During Extension.
AAPG Bull., 80, 1896–1924.
Scisciani, V. and Calamita, F., 2009.
Active intraplate deformation within
Adria: examples from the Adriatic
region. Tectonophysics, 476, 57–72.
Scrocca, D., 2006. Thrust front
segmentation induced by differential
slab retreat in the Apennines (Italy).
Terra Nova, 18, 154–161.
Scrocca, D., Doglioni, C., Innocenti, F.,
Manetti, P., Mazzotti, A., Bertelli, L.,
Burbi, L. and D’Offizi, S. (eds.), 2003.
CROP Atlas: seismic reflection profiles
of the Italian crust. Memorie Descrittive
della Carta Geologica d’Italia, 62, 193
pp. 71 plates.
Stewart, S.A., 2007. Salt tectonics in the
North Sea Basin: a structural style
template for seismic interpreters. In:
Deformation of the Continental Crust:
The Legacy of Mike Coward (A.C.
Ries, R.W.H. Butler and R.H.
Graham, eds), Geol. Soc. London Spec.
Publ., 272, 361–396.
Underhill, J.R., 1988. Triassic evaporites
and Plio-Quaternary diapirism in
western Greece. J. Geol. Soc. London,
145, 269–282.
Vandeville, B.C. and Jackson, M.P.A.,
1992. The fall of diapirs during thinskinned extension. Mar. Petrol. Geol.,
9, 354–371.
ViDEPI Project, 2012 (last upgrade).
Progetto ViDEPI - Visibilita Dati
Esplorazione Petrolifera in Italia.
http://unmig.sviluppoeconomico.gov.it/
videpi/
Zappaterra, E., 1990. Carbonate
paleogeographic sequences of the
periadriatic region. Boll. Soc. Geol. It.,
109, 5–20.
Zappaterra, E., 1994. Source-rock
distribution model of the Periadriatic
region. AAPG Bull., 78, 333–354.
Zelilidis, A., Kontopoulos, N., Avramidis,
P. and Piper, D.J.W., 1998. Tectonic
and sedimentological evolution of the
Pliocene-Quaternary basins of
Zakynthos island, Greece: case study of
the transition from compressional to
extensional tectonics. Basin Res., 10,
393–408.
Received 4 June 2013; revised version
accepted 21 October 2013
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Diapirism in the Adriatic Sea: the Tremiti salt structure • V. Festa et al.
Terra Nova, Vol 26, No. 3, 169–178
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