The discovery of a low-angle normal fault in the Taurus Mountains: the İvriz detachment and implications concerning the Cenozoic geology of southern Turkey

Turkish Journal of Earth Sciences

Turkish J Earth Sci
(2017) 26: 189-205
© TÜBİTAK
doi:10.3906/yer-1610-11

/>
Research Article

The discovery of a low-angle normal fault in the Taurus Mountains: the İvriz detachment
and implications concerning the Cenozoic geology of southern Turkey*
1,

1

1

2

3

Gürol SEYİTOĞLU *, Veysel IŞIK , Esra GÜRBÜZ , Alper GÜRBÜZ
Department of Geological Engineering, Tectonics Research Group, Ankara University, Gölbaşı, Ankara, Turkey
2
Department of Geological Engineering, Aksaray University, Aksaray, Turkey
3
Department of Geological Engineering, Ömer Halisdemir University, Niğde, Turkey
Received: 18.10.2016

Accepted/Published Online: 07.07.2017

Final Version: 24.08.2017

Abstract: The İvriz detachment fault has been determined on the southern border of the Ulukışla basin separating the metamorphic
Bolkar Group of the Taurus Mountains and the Paleocene-Lower Eocene Halkapınar formation of basin deposits. The fault dips towards
the north and has kinematic indicators (asymmetric grain/grain aggregate porphyroclasts, oblique foliation, and S-C fabrics), suggesting
a top-to-the-N-NE sense of shearing. The clastic material originating from the Bolkar Group in the sedimentary units of the Ulukışla
basin demonstrates that the detachment fault could have been be active during Latest Cretaceous-Eocene times. The İvriz detachment
may have initiated as part of a high-angle breakaway fault (the Aydos main breakaway fault) in the south of the Ulukışla basin. The
breakaway fault then rotated to a low-angle normal fault and its northern continuation played an important role in the exhumation of
the Central Anatolian Crystalline Complex. This implies that the Upper Cretaceous-Eocene sedimentary basins in central Anatolia were
supradetachment basins rather than collision- or arc-related basins as previously suggested.
Key words: Ulukışla basin, Taurus Mountains, detachment fault, extensional tectonics, Central Anatolian Crystalline Complex

1. Introduction
A detachment surface is one of the main tectonic elements
on highly extended terrains. Well-defined examples are
reported on the core complexes in the Basin and Range
Province of the western United States and in the Aegean
extensional province (i.e. Aegean Sea, Greece, western
Turkey) (e.g., Davis, 1980; Wernicke, 1981; Lister et al.,
1984; Bozkurt and Park, 1994; Hetzel et al. 1995; Gessner et
al., 2001; Işık and Tekeli, 2001; Işık et al., 2004; Jolivet and
Brun, 2010). Detachment faults are low-angle normal faults
separating mostly high-to medium-grade metamorphic
rocks from basin deposits and/or low-grade metamorphic
rocks (e.g., Davis and Lister, 1988; Lister and Davis, 1989).
The extensional nature of a detachment fault is shown by
a transition from ductile to brittle conditions (e.g., Işık et
al., 2003). The initiation mechanisms and evaluations of

detachment faults have been discussed elsewhere (e.g.,
Lister and Davis, 1989; Malavieille, 1993; Fletcher et al.,
1995; Buck, 1988; Wernicke and Axen, 1988; Seyitoğlu
et al., 2002, 2004; Ring et al., 2003; Tirel et al. 2008; van
Hinsbergen, 2010).
Central Turkey is one of the key areas in deciphering
Alpine orogeny, which includes the rocks of metamorphic
*Correspondence:

massifs (e.g., Kırşehir, Niğde, Akdağmadeni), oceanic crust
(e.g., İzmir-Ankara-Erzincan), variable intrusions (e.g.,
Ağaçören, Üçkapılı, Baranadağ), and basin deposits (e.g.,
Tuzgölü, Ulukışla, Sivas, Çankırı). There have been numerous
studies that particularly discuss the late Mesozoic-early
Cenozoic tectonic evolution of central Turkey and related
deformations within the scope of the process of closing the
Neotethys Ocean and its various branches. Therefore, the
origins of central Anatolian sedimentary basins have been
generally accepted as having developed through collisional
and postcollisional compressional tectonics over years
(e.g., Şengör and Yılmaz, 1981; Görür et al., 1984, 1998;
Gürer and Aldanmaz, 2002). Especially in the last decade,
however, evidence of extensional tectonics that controlled
the development of these basins as well as the exhumation
process of the Central Anatolian Crystalline Complex
(CACC; i.e. the Kırşehir-Niğde Massif) has been brought
forward and discussed by several scientists (e.g., Whitney
and Dilek, 1997; Gautier et al., 2002, 2008; Jaffey and
Robertson, 2005; Işık et al., 2008, 2014; Işık, 2009; Lefebvre
et al., 2015).

Our study suggests the existence of a low-angle normal
fault named here as the İvriz detachment, located between

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the Ulukışla basin and the Bolkar Group of the Taurus
Mountains in south-central Turkey. In this paper, first, the
geological setting of the area will be presented and then
the description of the detachment surface will be given.
Finally the implications of the detachment faulting on the
regional geology will be discussed.
2. Geological setting
The Taurus Mountains extend all along southern Turkey
and have been recognized as a linear structure since the
Eratosthenes map (c. 194 B.C.). Several tectonic units
constitute the complex structure of the Taurus Mountains
(Blumenthal, 1941; Brunn et al., 1971; Özgül, 1971,
1976, 1997; Demirtaşlı et al., 1975). The central part
of the mountains is mainly composed of the PermianCretaceous recrystallized limestone marble, slate, and
schist intercalations (i.e. the Bolkar Group of Demirtaşlı et
al., 1984) that represent the low-grade metamorphic rocks
of the Taurides in Figure 1. The Ulukışla basin (e.g., Oktay,
1982; Demirtaşlı et al., 1984; Clark and Robertson, 2002,
2005) is located between the central Taurus Mountains
and the CACC (Figure 2). The basin fill is considerably
well dated according to the paleontological data of
previous authors (e.g., Demirtaşlı et al., 1975, 1984; Gül
et al., 1984; Nazik and Gökçen, 1989; Alan et al., 2007;

Gürer et al., 2016; Figure 3). The detailed descriptions of
the formations can be found in the works of Demirtaşlı
et al. (1975, 1984) and Alan et al. (2007). The Upper
Cretaceous-middle Eocene basin fill is composed of the
Dedeli, Güneydağı, Halkapınar, and Ulukışla formations.
Ophiolitic olistoliths of the Dedeli formation, clastic rocks
of Halkapınar formation that originated from the Bolkar
Group, and volcanic material in the Ulukışla formation are
the prominent features of the Upper Cretaceous-middle
Eocene basin fill (Figures 2 and 3). The unconformably
overlain Delimahmutlu and Hasangazi formations
constitute the middle Eocene units (Figure 3). The Upper
Eocene-Lower Oligocene gypsum and anhydrite unit is
known as the Kabaktepe formation (Clark and Robertson,
2005; Meijers et al., 2016). The Upper Oligocene-Lower
Miocene Aktoprak formation is composed of conglomerate,
sandstone, marl, and limestone. Upper Miocene-Pliocene
fluviolacustrine deposits of the İnsuyu formation overlie
the earlier units with an angular unconformity (Figures
2 and 3). Quaternary alluvium, fluvial, and lacustrine
sediments unconformably cover the previous units.
On top of the Taurus Mountains, Lower PaleoceneLower Eocene sedimentary units unconformably overlie
the Bolkar Group (Demirtaşlı et al., 1984) (Figure 1).
Similar to other central Anatolian basins, the Ulukışla
basin has been interpreted by many scientists as a foreland
and/or forearc or intraarc basin (e.g., Şengör and Yılmaz,
1981; Oktay, 1982; Görür et al., 1984, 1998; Gürer et

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al., 2016), formed during the Neo-Tethys closure. The
southern margin of the Ulukışla basin is mapped as a
thrust fault verging towards the north, especially on its
eastern side (Demirtaşlı et al., 1984). In contrast, Dilek
et al. (1999) proposed that the southern margin of the
Ulukışla basin is a north-dipping high-angle normal
fault called the Bolkar Frontal Fault Zone, which was
active during Oligo-Miocene times (figure 3 in Dilek et
al., 1999). In the footwall of this fault zone, the Horoz
granitoid (47.17 ± 0.69 Ma: Ar/Ar hornblende; 54.3 ± 1.7
Ma; 50.44 ± 0.28 Ma: Ar/Ar biotite, Kuşçu et al., 2010;
56.1 Ma: U-Pb zircon, Kadıoğlu and Dilek, 2010; 49.1 ±
1.0 Ma to 50.6 ± 2.4 Ma: U-Pb zircon, Parlak et al., 2013)
added pebbles to the middle Eocene clastic rocks of the
Ulukışla basin (Sarıfakıoğlu et al., 2012) (Figure 2). Clark
and Robertson (2002, 2005) evaluated the subsidence
history of the basin fill and geochemistry of the volcanic
rocks and suggested that the Ulukışla basin developed
in an extensional or transtensional setting between the
Bolkar Carbonate Platform and the Niğde-Kırşehir massif.
Alpaslan et al. (2004, 2006) documented the sodic alkaline
and ultrapotassic nature of the volcanism in the Ulukışla
basin and suggested a postcollisional, extension-related
geodynamic setting.
The northern edge of the Ulukışla basin is bordered by
the Niğde metamorphic massif, which has been evaluated
as a core complex of the Oligocene-Miocene (Whitney
and Dilek, 1997; Fayon et al., 2001). However, Gautier et
al. (2002) indicated the Early-Middle Eocene sedimentary
units, which unconformably cover the southern Niğde

massif, including the pebbles of this massif. Thus, they
suggested that the massif must have been at the surface
before Eocene times or at least at the beginning of the
Eocene. Gautier et al. (2002) defined a detachment on top
of the Niğde dome. Whitney et al. (2003) documented
pervasive top-to-the-NNE shearing overprinted by topto-the south shearing and presented new geochronological
data indicating that the migmatites of the Niğde massif
are cut by the Üçkapılı granite, which shows coeval
emplacement with the Late Cretaceous extension. Gautier
et al. (2008) accept that the Niğde massif is a Cordillerantype core complex that developed along a detachment
having top-to-the-NE/ENE sense of shearing (location 1
in Figure 1). The opening of the Ulukışla basin and the
shearing along the detachment on the Niğde core complex
were evaluated as unrelated events (Gautier et al., 2008).
On the other hand, considerable isotopic dating data
have been published recently concerning the CACC. To
the north of the Niğde massif, on the northern side of the
CACC, the Kerkenez granitoid of the Yozgat batholith has
extensional mylonitic shear zones dated 71.6 ± 0.3 Ma and
71.7 ± 0.2 Ma (Ar/Ar, hornblende), showing a top-to-theNW shear sense (Işık et al., 2008) (location 2 in Figure 1).


SEYİTOĞLU et al. / Turkish J Earth Sci

Figure 1. Simplified geological map of the Central Anatolian Crystalline Complex and middle Taurides based on a 1:500,000 scale geological map of
Turkey by the MTA. [1] Top-to-the-NE sense of shear on a detachment on the Niğde massif (Gautier et al., 2002, 2008), [2] top-to-the-NW sense of
ductile shear from the Yozgat batholith (Işık et al., 2008), [3] top-to-the-SW sense of ductile shear on the Emizözü shear zone (Işık, 2009), [4] Kaman
detachment and top-to-the-NW sense of shear (Lefebvre, 2011; Lefebvre et al., 2011), [5] top-to-the-NE sense of shear of the Hırkadağ detachment
(Lefebvre, 2011; Advokaat et al., 2014; Lefebvre et al., 2015), [6] top-to-the-N-NE sense of shear on the İvriz detachment (this paper), [7] location of the
hypothetical Aydos main breakaway fault (this paper), [8] NE stretching lineations in the SE of Altınekin (Eren, 2000). NM: Niğde massif, AD: Akdağ

massif, KM: Kırşehir massif, YB: Yozgat batholith, AG: Ağaçören granitoid, BA: Baranadağ quartz-monzonite, HM: Hırkadağ massif.

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Figure 2. Geological map of the Ulukışla basin (modified from Atabey et al., 1990; Ulu, 2009; Alan et al., 2011a, 2011b; Gürbüz,
2016; the faults are after Yetiş, 1978; Demirtaşlı et al., 1984; Whitney and Dilek, 1997; Koçyiğit, 2003) and location of the İvriz
detachment.

To the NW of the Niğde massif, in the Ağaçören granitoid,
the Emizözü ductile shear zone with a top-to-the-SW sense
of shear is found (Işık, 2009) (location 3 in Figure 1). The
age of this ductile shear is estimated at around 78–71 Ma
(Işık, 2009) (Figure 1). Köksal et al. (2012) later published
an intrusion age for the Ağaçören granitoid in the range
of 84.1 ± 1.0 Ma and 73.6 ± 0.4 Ma (U-Pb, zircon). The
Kaman detachment has been recognized between the
marbles of the CACC and the ophiolitic rocks, with topto-the-W-NW normal shearing (Lefebvre et al., 2011)
(location 4 in Figure 1). The intrusion of the Baranadağ
quartz-monzonite postdated the ductile deformation, and
it is claimed that movement on the Kaman detachment
has ceased. The cooling period of the Baranadağ quartzmonzonite is 69–72 Ma and apatite fission track ages of 57–
60 Ma have been provided (Boztuğ and Jonckheere, 2007;
Boztuğ et al., 2009). 40Ar/39Ar dating of 72.11 ± 1.46 Ma
andesite has been reported in the basin fill of the AyhanBüyükkışla basin, which is related to the exhumation of the
CACC’s Hırkadağ massif (Advokaat et al., 2014; Lefebvre
et al., 2015) (location 5 in Figure 1). Recent studies using
paleomagnetic reconstructions suggest that the CACC

experienced nearly E-W extensional exhumation above

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an eastward-dipping subduction during late Cretaceous
times (Lefebvre, 2011; Lefebvre et al., 2013, 2015; Nairn et
al., 2013; van Hinsbergen et al., 2016).
3. Field observations
3.1. İvriz detachment
The İvriz detachment is observed to the southern margin of
the Ulukışla basin as a significant north-dipping low-angle
normal fault at İvriz village (location 6 in Figures 1, 2, and
4). The detachment surface separates the metamorphic
Bolkar Group from the nonmetamorphic Halkapınar
formation and ophiolitic mélange (Figures 5 and 6). In the
footwall of the İvriz detachment, the metamorphic Bolkar
Group is mainly composed of marble and mylonitic
marble. Calc-silicate phyllites and schists are also present
in the footwall. Fine to coarse-grained marble represents
the structurally lowest rocks of the footwall. Marble is the
most widespread and thickest rock unit in the study area.
It is mainly composed of calcite and dolomite, with up to
10% quartz, opaque minerals, and feldspar.
Marbles and schists/phyllites away from the
detachment show mylonitic foliation defined principally
by recrystallized and/or elongated carbonate minerals


SEYİTOĞLU et al. / Turkish J Earth Sci

Figure 3. The generalized stratigraphy of the Ulukışla basin (after Demirtaşlı et al., 1984; Alan et al., 2007; Gürbüz, 2016).

and traces of broken feldspars, plus recrystallized quartz,
sericite, and chlorite. Mylonitic foliation within the study
area strikes nearly east-west, with moderate dips to the
north. The development of mylonite and ultramylonite
in which carbonates are ductily deformed, but where
there is also a fracturing of feldspar grains, suggests
temperatures not in excess of 450 °C. Kinematic indicators
in the mylonites of the study include asymmetric grain/
grain aggregate porphyroclasts, oblique foliation, and S-C
fabrics, which suggest a top-to-the-N-NE sense of shear
(Figures 6a and 6b). The İvriz detachment is characterized
by a zone of brittle deformation in which footwall rocks are
pervasively fractured and brecciated. The zone of brittle
deformation (cataclastic zone) is up to ~50 m in thickness
in the study area, in which mylonitic marbles and calc-

silicate schists/phyllites are pervasively fractured and
turned into breccia (Figure 6c). Breccia is characterized
by mainly angular rock fragments with lesser amounts of
precipitated secondary minerals, such as calcite. Although
the main brittle deformation is attributed to the İvriz
detachment, mesoscale faults are seen in the cataclastic
zone. Down-dipping slickenlines on the İvriz detachment
are also typical.
A Paleocene-Eocene sequence (i.e. the Halkapınar
formation) that consists of conglomerate and sandstone
lies directly above the fault surface (Figure 6d). Clastic
components are polygenetic, containing marble,

recrystallized limestone, mylonitic marble, phyllite, and
quartzite, which are similar to those within the underlying
footwall rock (Figure 6e).

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Figure 4. A-A’ cross section (upper part). See Figure 2 for location and legend. (a) A field photo of the İvriz detachment; (b)
interpreted version of the field photo of the İvriz detachment.

Further to the east, the İvriz detachment can be followed
around Kayasaray, where the ophiolites and olistoliths are
found on the hanging wall (Figures 2, 7, and 8).
3.1.1. The age of İvriz detachment
Based on its fossil content, the age of the Halkapınar
formation, which is in the hanging wall of the İvriz
detachment, is Paleocene-Early Eocene (Demirtaşlı et
al., 1975, 1984; Sirel, 1981, personal communication,
2013; Alan et al., 2007; Gürbüz, 2016) (Figure 3).
Immediately NW of İvriz, the Halkapınar formation
contains conglomerates that contain cobbles/pebbles

194

of the Bolkar Group (Figures 2 and 4), and the dipping
of beds gradually decreases upwards. Further to the
north, towards relatively lower stratigraphical levels, the
Halkapınar formation contains block-sized materials

composed of ophiolites and recrystallized limestones of
the Bolkar Group. The provenance analysis of Clark and
Robertson (2005; page 24) also indicates that the Upper
Cretaceous-Paleocene units contain grains of the Bolkar
Group. These stratigraphical restrictions are consistent
with the Paleocene-Eocene isotopic dating of the Horoz
granitoid (see above) that shows an intrusive contact with
the Bolkar Group in brittle conditions.


SEYİTOĞLU et al. / Turkish J Earth Sci

Figure 5. Detailed geological map of the İvriz detachment around
İvriz village. For location see Figure 2. Black dashed line shows the
location of Figure 6.

This evidence indicates that during Latest CretaceousEarly Eocene times, the Bolkar Group was exhumed by
normal faulting on the İvriz detachment.
3.2. Synsedimentary faulting and deformation of the
Ulukışla basin fill
The Upper Cretaceous-middle Eocene units of the Ulukışla
basin are deformed by several thrust faults (Figure 9),
but careful examination in the field demonstrates that
the units contain synsedimentary normal faults (Figure
10), indicating that its deposition occurred under an
extensional tectonic regime. This observation is supported
by the İvriz detachment determined in this study and
by the alkaline character of volcanism that developed
simultaneously with the Ulukışla formation (e.g., Alpaslan
et al., 2004, 2006). The synsedimentary normal faults

in the Upper Cretaceous-middle Eocene sequence are
overprinted by thrust faults (Figure 10), indicating a postmiddle Eocene contraction. This contraction affected
the eastern continuation of the İvriz detachment surface
and the Bolkar Group thrusts onto the Ulukışla basin fill
around Maden village (Figures 2, 11, and 12). The Upper
Oligocene-Lower Miocene Aktoprak formation is limited
by a north-dipping normal fault. A drag-fold syncline
developed on the hanging wall of this normal fault
(Figure 7). The Aktoprak formation is deformed by thrust
faulting near Yeniyıldız village (Figure 2). The intensity of

deformation is different in the Upper Cretaceous-middle
Eocene units (several folds and thrusts) and the Upper
Oligocene-Lower Miocene sequence (overall a single drag
fold syncline). Therefore, it can be said that the Ulukışla
basin fill was affected by two different contractional events
during post-middle Eocene and post-Oligocene times.
These data concur with the dating of the Savcılı thrust,
further north in central Anatolia (Işık et al. 2014).
4. Discussion
In the earlier studies mentioned before, the CACC
magmatism and the development of surrounding
basins are generally accepted as collision or arc-related.
Increasing evidence of extensional exhumation data from
the CACC together with the reported İvriz detachment
in the southern margin of the Ulukışla basin create an
obligation to reopen discussion of the regional geology.
The observation of the İvriz detachment in the south
of the Ulukışla basin can be explained as follows (Figures
13 and 14). The İvriz detachment had a high-angle origin

and operated as a main breakaway fault, termed here as the
Aydos main breakaway fault, that controlled deposition
of the Ulukışla basin fill during the latest CretaceousEocene times (location 7 in Figures 1 and 13a). During
the Paleocene-Eocene, the basin fill overlapped the main
breakaway fault. The remnant of this overlapped unit can

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Figure 6. a) Simplified geological cross-section of the border between the Taurus Mountains and the Ulukışla basin showing the detailed nature of the
İvriz detachment fault with locations of photomicrograph and photographs labeled as b, c, d, and e. b) Photomicrograph in crossed polarized light of
oblique foliation (of) and S-foliation (S) and mylonitic foliation (mf) creating the kinematic indicator called S-C fabric in mylonitic marble. Note that
oblique foliation and S-C fabric suggest a top-to-the-north sense of shearing. c) Field photograph of breccia below the detachment fault surface. d)
Photograph of the detachment fault surface and contact between the fault and the overlying conglomerate. Notice the striations on the fault surface. e)
Close-up field view of conglomerate with mostly gray and light brown clasts of the Bolkar Group.

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Figure 7. Kayasaray cross-section of the İvriz detachment. For location and legend see Figure 2.

Figure 8. a) Uninterpreted field photo of the İvriz detachment east of İvriz at Kayasaray; b) interpreted photo.

be observed on top of the Taurus Mountains today. Later,
the high-angle main breakaway transformed into the lowangle normal fault, the İvriz detachment, probably due to
a rolling hinge mechanism like in western Turkey (i.e. the

Alaşehir type rolling hinge mechanism: Seyitoğlu et al.,

2002, 2014) (Figure 13b). Its lateral northwest continuation
probably creates the Altınekin stretching lineations (Eren
2000) (location 8 in Figure 1). Along the north-northeast
continuation of the up-bulged Aydos main breakaway, the
CACC exhumed as an asymmetrical core complex, likely

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Figure 9. Deformed Paleocene-Eocene units in the Ulukışla basin. See Figure 2 for location and legend.

Figure 10. Field photo of synsedimentary normal faults overprinted by thrusting in Paleocene-Eocene units of the Ulukışla basin.
Location is at the north of Kolsuz; see Figure 2.

Figure 11. Cross-section of Maden and Gümüşköy that shows the southern margin of the Ulukışla basin. For location and legend
see Figure 2.

formed as an elliptical dome shape in map view (Lefebvre,
2011) (Figures 14a–14c). Top-to-the-SW movement on
the Emizözü ductile shear zone (Işık, 2009) (location 3 in
Figure 1) and top-to-NNE shearing overprinted by top-tosouth shearing in the Niğde massif (Whitney et al., 2003)
(location 1 in Figure 1; Figure 14c) are possibly related

198

to the slight southward slip on the main breakaway fault

because of the doming of the CACC.
The correlation of metamorphic grade between the
footwall of the İvriz detachment (this paper) and the
Niğde massif (e.g., Gautier et al., 2008) indicates that
relatively deeper sections of the crust exhumed in the


Figure 12. Field photo of thrust fault cutting the İvriz detachment near Maden village at the southern margin of the Ulukışla basin.

SEYİTOĞLU et al. / Turkish J Earth Sci

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Figure 13. The regional tectonic interpretation of the İvriz detachment. K: Kaman detachment (Lefebvre, 2011; Lefebvre et al.,
2011), Y: Yozgat batholith ductile shear zone (Işık et al., 2008), H: Hırkadağ detachment (Lefebvre, 2011; Advokaat et al., 2014;
Lefebvre et al., 2015), E: Emizözü ductile shear zone (Işık, 2009), N: Niğde detachment (Gautier et al., 2002, 2008), A: Altınekin
stretching lineations (Eren, 2000), I: İvriz detachment (this paper). CACC: Central Anatolian Crystalline Complex, STZ: Savcılı
Thrust Zone (Işık et al., 2014).

Figure 14. The Aydos main breakaway fault. Development of the İvriz detachment and its role in the exhumation of the CACC.

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Figure 14. (Continued).

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north. The reason for the relatively shallow layers of the
crustal exhumation along the vriz detachment is probably
the rolling hinge mechanism of the Aydos main breakaway
fault in the south of the Ulukla basin.
The stratigraphy of the Ulukla basin has an Upper
Cretaceous-Middle Eocene transgressive sequence and
Upper Eocene-Lower Oligocene gypsum units (Figure
3). The transition from deep sedimentary environment to
shallow conditions towards the Late Paleogene could be
related to the exhumation of the Nide massif that created
shallow sedimentary conditions for the northern margin
of the Ulukla basin (Figure 14d).
Post-Eocene contractional structures can be seen in
both the CACC and inside the Ulukla basin as well as on
its southern margin (Figures 13c, 14e, and 14f).
This hypothesis indicates the formation of an
asymmetrical core complex with top-to-the-NE shearing
for the CACC and evaluates the central Anatolian basins
as supradetachment basins. There is no need for a
subduction under the CACC to explain igneous activity
as previous studies suggested (e.g., Lefebvre, 2011;
van Hinsbergen et al., 2016). During the core complex
formation, delamination of the lithosphere can create synand postexhumation magmatic activity (e.g. Cordilleran,
western US Wells and Hoisch, 2008; Liaonan, northern
China Ji et al., 2015).

Discovery of the vriz detachment in the Taurus
Mountains may be a missing part of a puzzle regarding the
exhumation of the CACC.
5. Conclusion
This paper documents the first records of a low-angle
normal fault in the Taurus Mountains. The vriz detachment
separates the metamorphic Bolkar Group from the
ophiolitic rocks and sedimentary fill of the Ulukla basin.
Geological relationships indicate that the vriz detachment
operated during latest Cretaceous-Eocene times. Discovery
of the vriz detachment would change the perception
of the tectonic style in south and central Anatolian
sedimentary basins from collision/arc-related basins to
supradetachment basins and opens up the possibility for
more meaningful explanations of the exhumation history
of the CACC, including the Nide massif.
Acknowledgments
This study was partly supported by ASĩBAP (Aksaray
University, Scientific Research Projects, Grant No: 201371). The authors are grateful to A Yldz (ASĩ), N Kazanc,
and E Sirel (Aĩ) for their contributions and fruitful
discussions, and the three reviewers for their criticisms that
improved the manuscript significantly. EG acknowledges
support from the Scientific and Technological Research
Council of Turkey (TĩBTAK BDEB 2211-A).

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