THRUST FAULT TECTONICS IN THE DUHOK REGION (HIGH … · groups. One group is E-W and the other...
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International Journal of Civil Engineering and Technology (IJCIET)
Volume 6, Issue 10, Oct 2015, pp. 132-146, Article ID: IJCIET_06_10_012
Available online at
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ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication
THRUST FAULT TECTONICS IN THE
DUHOK REGION (HIGH FOLDED ZONE, N
IRAQ)
Mustafa R. S. Al-Obaidi
Department of Geology, College of Science, University of Baghdad, Iraq
Ahmed A. H. Al-Moadhen
Department of Geology, College of Science, University of Baghdad, Iraq
ABSTRACT:
The Alpine thrust and associated fold structures of the Duhok region (High
Folded Zone, N Iraq) are interpreted in terms of thin skinned tectonics, with
dominate northward and southward transport direction. A 5 Km thick
sequence of Mesozoic-Tertiary rocks was deformed by continuous squeezing
between Arabian plate and Iranian-Anatolian plates, the thrust planes on the
layer boundaries developed. These thrust system includes an imbricate fan
and a duplex. The thrust surfaces have an irregular map outcrop pattern due
to the existence of a set of folds. A strike -normal balanced cross section
illustrates the geometry of the thrusts and their related folds. The minimum
value of accumulated transport is about 23.17 Km. Folding are related to
frontal hanging–wall ramps.
Key words: Structural geology, Thrust Systems, High Folded Zone, Iraq.
Cite this Article: Mustafa R. S. Al-Obaidi and Ahmed A. H. Al-Moadhen.
Thrust Fault Tectonics In The Duhok Region (High Folded Zone, N Iraq).
International Journal of Civil Engineering and Technology, 6(10), 2015, pp.
132-146.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=6&IType=10
1. INTRODUCTION
The external zone of Alpine orogenic belt in the north and northeast of the Arabian
Peninsula, named the High Folded Zone, constitutes an arcuate foreland thrust and
fold belt. The study area covers about 4500 square kilometers within in the Iraqi
Kurdistan Region. The area is located within the Duhok governments (Figure 1). In
the Duhok Region a great number of thrusts are known to affect and to cause the
repetition of some parts of the sequence. Most previous workers have relied on
surface observations collected during geological mapping or stratgraphical
investigation although more recently subsurface drilling and seismic methods have
increased the knowledge of the subsurface structures. In addition, in order to provide
Thrust Fault Tectonics In The Duhok Region (High Folded Zone, N Iraq)
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the necessary control for interpretation of the collected data, a review of available
information was undertaking relating to the geology of Kurdistan and previous
geological investigations in the area.
The studied area include eleven folds, these folds are: Ber Bahr, Geri Baran,
Shaikh Adi, Central Duhok, Duhok, Shaikhan, Atrush, Swara Tika, West Duhok,
Tawke and Gara Anticlines. Forty two major thrust faults are present in the study area
and are possible for considerable deformation at the area. These thrusts, which extend
several meters to more than 10 km along the regional strike, are evident from surface
of crops and from field data. It appears from the map that an orientation is in two
groups. One group is E-W and the other group is NW-SE. Mostly are dipping to the
south and to the north and some other to NE and SW.
Figure 1 Base map of Northern Iraq denoting geographical location of the study area
(red polygon) showing the distribution of the folds and cross sections in the Duhok
Region.
Many studies have been suggested to understand the tectonic evolution of this part
of the world. The most accepted one at present is the "constructional thrust fault
hypothesis" which explains in High Folded Zone as a result of thrust movement,
where the Arabian plate in the south move northward relative to Iranian and Anatolian
plates in the east and north. The area has been studied by several authors (Al-Alawi,
1980, Al Naqib, 1980 and prepared a detailed geological map scale (1: 20000) and
AL–Abd Allah, 2009).
This paper is based on the reinterpretation of the published maps of Sissakian,
(1995) and new data obtained by the authors. The structural interpretation of Duhok
region described in this paper is based mainly on geometrical analysis using balanced
cross sections (Dahlstrom, 1970). The aim of this work is to present an interpretation
of thrust geometry of the Duhok region and to produce a balanced cross section and a
preliminary kinematic interpretation. Four transverse cross -sections, show the thrust
geometry as well as the genetic relationships between folds and thrusts.
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2. GEOLOGIC SETTING
The thrust system in the Duhok region presents a very irregular map pattern because
the thrusts have been affected by a later set of folds. The thrust system produced
determination in a sequence of Mesozoic and Tertiary rocks. The stratigraphy of study
area (Figure 2) is characteristic for the whole of Iraq’s High Folded Zone. The
sedimentary succession (about 27 formations) is possibly more than 5 km thick and
quite probably begins with a ductile Upper Precambrian series. The study area is
topped by a several thousand meter thick Paleozoic–Lower Mesozoic succession, of
which the shallow-water carbonates of the Permian Chia Zairi and Triassic Kurra
chine formations form thicker, more rigid units (van Bellen et al., 1959/2005; Jassim
and Goff, 2006).
Figure 2 Geologic map showing the distribution of folds and thrusts in study area
(modify after Sissakian, 1995).
The Jurassic succession begins with a several hundred meters thick neritic
carbonate, also generally rigid. In the Middle Jurassic this dolomitic platform passes
laterally to evaporites (Alan and Adaiyah formations). In the upper Middle Jurassic
and Upper Jurassic there is a widespread, yet thin basinal facies, divided into the
Sargelu and Naokelekan formations, which is believed to be one of the source rocks
of the area. In regions exposed to compression these two formations might be
effective décollements. In the Upper Jurassic the Sargelu and Naokelekan formations
are overlain either by neritic dolomites (Barsarin Formation) or evaporates (Gotnia
Formation) in this region (Csontos et al., 2012).
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In the Early Cretaceous the basinal sedimentary Chia Gara shale and marl was
deposited. Locally this unit can also be a décollement. It passes upwards into the
Sarmord/Balambo marl and then the Qamchuka neritic carbonate. Above a minor
unconformity in the middle Cretaceous, an Upper Cretaceous platform carbonate
represented by the Bekhme and Aqra carbonate was deposited. This platform passes
laterally and upwards into basinal sediments (Shiranish and Tanjero marl). The upper
part of the deep-marine marl may also be Paleocene in age (Kholosh Formation;
Sarbazheri et al., 2009). The Cretaceous neritic carbonates (Qamchuka, Bekhme-Aqra
formations) form a 600 m thick rigid and weathering resistant structural level that can
be used to determine the wavelength of folds.
A more rigid carbonate unit (Palaeogene Khurmala-Sinjar Formation) is overlain
by very characteristic, brick-red Eocene clays forming a detachment horizon (Gercus
Formation) and by a thin and chalkydolomitic Eocene carbonate (Pila Spi Formation).
This rigid unit forms very characteristic outcrop exposure patterns and is easily
recognised even on satellite photos (Csontos et al., 2012). The Neogene is
represented by (1) the sometimes evaporitic, variegated Middle Miocene Lower Fars
Formation; (2) the mostly sandy, fluvial Middle–Upper Miocene Upper Fars
Formation; and (3) the conglomeratic Upper Miocene Pliocene Bakhtiari Formation.
These Neogene formations have a cumulative thickness of more than 1,500 m (Jassim
and Goff, 2006).
Tectonically, the fold-thrust belt in the Kurdistan Region of Iraq is divided into
four NW-SE striking tectonic units (Jassim and Goff, 2006): the Zagros Suture, the
Imbricated Zones, the High Folded Zone (equivalent to the Simply Folded Belt in the
Iranian part of the Zagros) and the Foothill Zone. The study area is lying within High
Folded Zone (Berberian, 1995; Jassim and Goff, 2006; McQuarrie, 2004).
3. STRUCTURE
The most outstanding feature of the Duhok region is the existence of a set of thrusts
affected by longitudinal folds with variable geometrics and distribution. Many major
thrust sheets with imbricate fan system and duplex form the thrust system of this
region (Figure 3 &4). Other important structures in the area are: sets of superposed
folds: one with axial traces parallel to the map outcrops of the thrust surfaces
(longitudinal system), and another set with axial traces not parallel to the map outcrop
of the thrust surface. Between them, there are broad flat bottom synclines.
Figure 3 Photographic section showing the development of Pop-up structure and
Triangle zone in the Shiranish Formation on southern limb of Ber Baher anticline.
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Figure 4 Several thrust fault planes in the Pila Spi Formation - northern limb of Gara
anticline, which are dipping to the north and which separates four thrust sheets.
4. SECTION PARALLEL TO THE TRANSPORT DIRECTION OF
THE FOLD- THRUST BELT
An approximately N-S or NNE-SSW cross sections through the Duhok region are
shown in Figure (1). These have been constructed perpendicular to the axial direction
transport direction of the belt. The structure of these sections consists of a system of
thrusts branching from a sole thrust located near the base of Chia Zairi Formation
(Satina member-Permian). This sole thrust generally has a constant dip forwards the
NE. A prominent of these sections is the gradual increase in the number of thrusts
towards the internal part of the system where a duplex is present. Two different types
of thrusts can be distinguished, the first one with dominate SW ward transport
direction and the second one with a dominant NE ward transport direction.
The first group includes thrusts surfaces that branch from the sole thrusts which is
parallel to the bedding. Most of the thrusts in these sections are of this type. Footwall
and hanging wall ramps and flats can be observed as well as the folds related to the
hanging wall ramps. In this Figure it is also possible to see a thrust that represents a
decollement surface. The second group of thrusts is those that form the duplex. These
also branch from the sole thrust, but converge upwards into a roof thrust that is the
decollement of the Taurus – Zagros belt. The third type comprises a thrust that started
from a floor fault and propagated upwards cutting the base of previously emplaced
thrust slices. This fault reactivated the floor thrust of duplex and was responsible for
the uplifting of the duplex. Related to its emplacement an antiformal culmination was
formed and produced the back relation of the thrusts located behind it (Figure 5).
Figure 5 Photographic section showing the position of duplex thrust plane system in
hinge of the Ber Baher anticline.
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These cross sections show several folds developed within the thrust sheets. The
folds are related to hangingwall frontal ramps (fault bend folds, Suppe 1983, leading
edge folds, Boyer 1986). They are often anticlines, and are usually located at the
frontal part of the sheets. The process of formation of these folds can be interpreted to
be directly caused by the thrusts emplacement. Some of these thrust faults are listed
below:
A. Ber Bahr Thrust Fault: This fault is subsurface thrust fault with dip that
decrease with depth and the length of fault is about 12 Km. The decollement surface
for the BB1 thrust fault is placed within the Permian- Triassic ages.
B. Sheikh Adi Thrust Faults: The Sheikh Adi anticline is a compressional
anticline, with significant over‐thrusting of the hanging wall in a southerly direction.
A bifurcation of the southerly thrust fault can be interpreted to the west of the Sheikh
Adi structure, which defines a separate prospect in the hanging‐wall limb, termed here
the Sheikh Adi Hanging Wall prospect.
C. Shaikhan Thrust Faults: Using a combination of seismic mapping,
extrapolation of structural dip, well formation dip and mapped surface structure, Gulf
Keystone Petroleum (2014) has constructed a depth structure map of the Shaikhan
anticline (Figure 6). In its simplest terms, the structure is a compressional, asymmetric
anticline, with a faulted northern limb and a subsidiary back fault developing to the
south. It maps as dip closed plunging eastwards, and appears to be separated from the
Sheikh Adi structure by a saddle structure.
Figure 6: A) North-to-south dip seismic section of shiakhan structure. B) North-to-
south dip seismic section of Shiakhan structure (Gulf Keystone Petroleum, 2010).
D. West Duhok Thrust Faults: West Duhok structure is a separate anticline
located to the north west of study area (Figure. DNO International has mapped the
West Duhok structure using 3D seismic data (DNO International, 2012). The structure
is a compressional anticline, with two major thrust faults in the north and south limbs.
E. Geri Baran Thrust Faults: The Geri Baran anticline is a compressional
anticline, with two major thrust faults in the north and south limbs.
F. Central Duhok Thrust Faults: The Central Duhok anticline is a compressional
anticline, with two major thrust faults in the north east and south west limbs.
G. Tawke Thrust Faults: Eight major thrust faults and several low displacement
faults were also interpreted in the area.
H. Duhok Thrust Faults: In the Duhok anticline, there are two major thrust faults .
I. Atrush Thrust Faults: The Atrush anticline is a complex faulted anticlinal
structure visible both at surface and in the seismic data. Upper Cretaceous, Aqra-
Bekhme carbonates are mostly mapped at surface however locally Qamchuqa
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sediments may be exposed. The Atrush anticline developed along a possible shallow
thrust zone oriented east-west with Six major thrust fault.
J. Swara Tika Thrust Faults: The Swara Tika anticline is covered by a grid of 2D
seismic data, three seismic lines provide structural control (Figure 7) (Macquarie
Explorers Conference, 2013).
Figure 7 A north to south dip section of Atrush anticline (General Exploration
Partners, 2014).
5. METHODOLOGY
The tectonic transport direction at Duhok area is deduces from Bow and arrow Rule
(Elliott and Johnson 1980). In this method a straight line is drown connecting the two
ends (tip points) of the outcrop trace of a single thrust. The perpendicular bisector of
this line give an estimate of the slip direction and the length of the line is an estimate
of the displacement (Figure 8) and table (1). The initial regional section should be
constructed near areas of maximum thrust displacement using the "Bow and Arrow"
rule of Elliott (1976).
Table 1 Displacement estimates of the main thrusts by Bow and Arrow rule of the Duhok
Region.
Direction Accumulated
Displacement
Displacement
(Km) Location
N5E 2.2 2.2 Duhok anticline
S40W 4.99 2.79 Ber Baher and Shiak Adi anticlines
S3W 7.47 2.48 Shaikhan
N5E 10.33 2.86 Atrush anticline 1
N5E 12.41 2.08 Atrush anticline 2
S10W 14.26 1.85 Gara anticline 1
N5E 16.72 2.46 Gara anticline 2
N40E 20.32 3.6 Central Duhok anticline
N 22.14 1.82 Tawke anticline
N10S 23.17 1.03 West Duhok anticline
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According to above table, the displacement on each thrust surface in the study
area is ranges between (1-3 Km).
The other most important method which was used in this study was the technique
of constructing balanced cross sections. A "balance" is said to exist in a cross-section
when bed length, or a cross-sectional areas, are equal in both the deformed and
undeformed states (Elliott 1981). An estimation of the orogenic contraction across
High Folded Zone (study area) can be obtained from a comparison between
simultaneously constructed deformed and restored cross-sections whereby the
difference between the restored section length give the amount of shortening (Elliote
and Johnson, 1980 and Salih, 1990). These cross sections are drawn for planes
parallel to the shortening direction.
After determining the approximate Transport Direction specific locations for the
cross section were selected. Lines of section have been chosen which are parallel to
the thrust transport direction and run from the south margin of the study area to the
north of it. The restored cross section is drown with key beds (e,g, Chia Gara, Kurra
Chine formations). The sections were graphically restored to their underformed state
using the constant bed length technique. Percentage shortening of a given bed was
calculated from this equation.
------------------------ Eq.1
Where Lo = the initial length of the bed before the deformation and L= the final
length of the bed after deformation.
In Figure 9B, 10B, 11B and 12 B a complete restoration of parts of sections 9A,
10A, 11A and 12A can be seen. In these sections imbricate fanes have been restored,
showing by means of line the position of thrust surface. Some of these thrusts
associated with it have a different transport direction. In these structures, four thrust
sheets outcrop in its northern part, whilst in its southern part at least two more thrusts.
Figure 8 The Bow and Arrow rule as applied to determine transport direction in the study
area.
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The thrust fault have two different types of map patterns, either linear or slightly
curved changing from an E-W direction in the internal part to NW-SE in the external
zone. During this process piggy- back thrusts were also generated.
6. THE KINEMATICS OF EMPLACEMENT OF THRUST
SHEETS
According to the assumption that the length of the beds in the cross sections remain
constant during the formation, the total of the tectonic shortening in the study area is a
combined result of thrusting and folding. As discussed in the above sections and
"Bow and Arrow" method, the transport direction in this area is mostly in a N-S,
NNE-SSW directions. From the map and from the cross – sections described in this
paper, preliminary conclusion may be made on the kinematics of emplacement of the
Duhok thrust sheets. It has been assumed that the emplacement occurred from north to
south for the first thrust system. The displacement of the different thrust sheets and
thrust systems have been calculated (Table 1). The total accumulated displacement for
these sections is of the order of 23.17 Km.
The duplex has been balanced separately using the length of the beds. The
shortening undergone by the restored set is about 27%. The emplacement of these
duplexes caused the bending of the thrust sheets located above it, the curvature the
topography of the duplex. The later fault caused the frontal part of the duplexes to be
uplifted as a Pop-Up structure and the back rotation of the rear thrusts. Based on the
structural contour maps, N-S and NNE-SSW cross sections and the method for
estimating shortening, the estimated initial length of the Chia Gara formation as
example in section(C-C') is equal to about (12.9) Km and the final length which
equals about (9.8) Km. For the same bed, the shortening percentage for the area is
about 24 % (Table 2). As illustrated in (Figure 9, 10, 11 and 12) and (Table 2) shows
the calculated shortening percentage for different cross sections in the studied area.
These results reflect that the study area is affected by inhomogeneous deformation.
Figure 9 Above present and completely restored section of beds in the study area
between Shaikhan and Swara Tika anticlines
A
B
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Figure 10 Above present and completely restored section of beds in the study area
.between Duhok and Gara anticlines
A
B
Figure 11 Above present and completely restored section of beds in the study area
between Duhok and Shaik adi anticlines
A
B
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Table 2 Shortening estimates by Balanced Cross Section Method along the four cross
sections in the study area.
Section Formation Original length
(Km)
Final length
(Km)
Shortening
(Km)
Shortening
%
Shortening
(Mean) %
A-A'
Butmah 24.2 22.88 1.32 5 5
Qamchuqa 24 22.88 1.12 5
B-B'
Barsaren 36.36 31.66 4.7 13 17
Baluti 40.42 31.66 8.76 21
C-C'
Chia Gara 12.9 9.8 3,1 24 25.5
Kurra Chine 13.4 9.8 3.6 27
D-D'
Shiranish 9.5 8.03 1.47 15 10
Kurra Chine 8.6 8.03 0.57 6
The different shortening or deformations could be related to the ramp orientation
with transport direction or to the type and thickness of rock unites. Balanced cross-
sections were constructed across the Dohuk, Ber Baher, Gara, Shaik-Adi, Shaikhan,
Atrush, Swara Tika and West Duhok anticlines (Figure 9, 10, 11 and 12). The cross-
sections were balanced using the sinuous bed method (Dahlstrom, 1970).
Although the maps show detailed surface geology, important aspects of the Zagros
orogen are not known, such as the dip of the basement surface and the stratigraphic
level of the master de´collement (base of Cambrian section or within the basement).
The following discussion describes and provides the rationale for the interpretations
of the structures that are shown in the balanced cross-sections. The interpretations are
based on map patterns, strike and dip data, changes in stratigraphic thicknesses across
strike, select borehole data. The published seismic data provided knowing completely
the geometry of structures at depth, the depth to basement or how basement
topography may change through the orogeny (McQuarrie, 2003).
The Restoration of the balanced cross section provides the minimum estimate of
horizontal shortening. Along the transect A–A' through shaikan – Atrush - Swara
Tika anticlines section, the shortening magnitude is 5% (Table 2) and the shortening
magnitude along the transect B–B' across the Dohuk-Ber Baher- Gara anticlines
Figure 12 Above present and completely restored section of beds in the West
Duhok anticline
A
B
Thrust Fault Tectonics In The Duhok Region (High Folded Zone, N Iraq)
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section is 13-21 % but the shortening magnitude along the transect C–C' across the
Duhok-Shaik Adi anticlines section is 24-27% where the shortening magnitude along
the transect D–D' across the West Duhok anticlines section is 6-15 %.
7. DISCUSSION
Many ideas have been offered by different workers to explain the folded structure
features in the thrust region. The complex geometric implications of the interrelations
between the fold and fault structures have been investigated in detail by Boyer and
Elliotte (1982) and Suppe (1983). The above results indicate that a sequence of easy
differential slip thrust had been produced as a nearly bed-parallel set of structures
along the incompetent beds. Continued differential movement (movement on the
upper beds is greater than in the lower beds) on the gentle limbs results in steeping,
overturning and break- through all the other limbs.
As a result of the squeezing of the sequence, accommodation structures
(Rotational and back thrust) have been formed. It could be the back thrust faults
formed in response to the flexural slip folding. Many new faults surface developed as
a result of this deformation. It appears from those observations and the observation
elsewhere by Salih and Al-Dahgstan y (1993) Serra (1977) that the mechanisms of
deformation and the resulting structural styles in this area can vary according to the
type of rocks involved in the faulting and the thickness of the individual rock types
with respect to the ramp angles and vertical separation of the ramp. It could be that
these reasons explain the more folded state of beds in the upper part of the section
than in the lower. The factor of pre-existing bedding parallel mechanical isotropy
created by strong lithological differences is one of the most important factors
determining the style of deformation in the study area.
The Duhok Region is characterized mostly by a hinter land-dipping series of
duplex structures. In some areas the shortening by the displacement on thrusts is
greater than that by folding. This may reflect the behavior of the rocks in this area.
According to these results, it is difficult also to explain the features in terms of
shortening alone and for an explanation of these features folding term are also used.
From the above discussion, the relationship between thrusting and folding in the
study area is not simple and this complexity is caused by:
Simultaneous faulting and folding. or
Faulting and folding are formed in different times.
According to evolve ideas, folding in the study area is take place mostly in the
hanging wall (e.g. hanging wall anticlines). Geologists refer to the Fold Thrust belts
as “ Fold-Thrust Belts ” because, in addition to the thrust systems that we have just
described, these belts contain spectacular folds, with amplitudes ranging from
millimeters up to a few kilometers, these folds call “ thrust-related folds ” because
they form in association with displacement on thrust faults. According to Jamison
(1987) and based on Van der Pluijm and Marshak (2004) models, the model of the
"folding –during –thrusting or Fault-bend folding model is more compatible with the
results present in Figure (2). This model involves a close relationship between the
formation of folds and the propagation and movement of thrusts, when a layer-parallel
thrust cut through stratigraphy, and then flattens again in a stratigraphically higher
detachment (Johnson and Berger, 1989; Rich, 1934; Suppe, 1983).
Most of these structures are located in the northern part of the areas where the
hanging-wall moves to the south. The anticlines located on the frontal Ramps and
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some others are located on the oblique ramps. Based on present data and on above
assumption, the incompetent Rock units bellow the Pila Spi formation as example
contains one of major detachment surfaces (e.g. Gercus formation and all rock units
above) that rocks in the hanging-wall. These thrusts are thought to propagate mainly
in the transport direction, beginning with sole (Detachment) thrust lower in the
succession out of this thrust a series of a thrust develop. Numerous thrust
progressively develop in the transport directions and are almost layer parallel. These
thrusts merge together to form a roof thrust. These results agree with other studies
(e.g. Salih and Al Dahgstani 1993).
All these evidences (beds have behaved as detachment surface, long flats, short
ramps, hinter land dipping duplex and pop-up structures) which are present in the
study area support the thin skin tectonic model.
8. CONCLUSIONS
The Duhok region forms one of the most thrust units in the arcute foreland thrust and
fold belt of the Taurus-Zagros orogenic belt in the Arabian Peninsula. The Duhok
region is located in the southern part of this belt and its main structural feature is the
presence of several thrusts branching from sole thrust located in the ---- Fn. (age ) and
a cross –folding system. These thrust systems with dominate southwestward and
northeastward transport direction, presents six major thrust sheets as well as an
imbricate fan system and a duplex. The minimum value of accumulated displacement
is 23.17 km. Folds within the sheets are related to frontal hanging-wall ramps. The
folds deforming the thrust surfaces are related to roof topography of underlying thrust
systems. This system of faults forms a second thrust system (including back thrusts
with piggy back sequences), and reactivated the earlier thrust system.
So, the folds and thrust patterns have evolved as expression of shortening which is
approximately N-S or NE-SW directed and sub parallel to the bedding. Due to
continuous squeezing between Arabian plate and Iranian-Anatolian plates, the thrust
planes on the layer boundaries developed. These thrusts are explained as thrusts
splaying to the northeast and southwest (Figure 13). The study area was percent is
equal to 20-24%. So, thin skin thrusting model is more acceptable to interpretation of
structures in the Duhok Region.
Figure 13 Sketch showing the development of the study area and the relationship
between folding and thrusting
Thrust Fault Tectonics In The Duhok Region (High Folded Zone, N Iraq)
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9. REFERENCES
[1] Al-Alawi, M. N. T., 1980. Structural study of upper Cretaceous and Tertiary
Succession in Jebal Bekhir, Dohuk area, north Iraq. Unpublished M.Sc.thesis,
University of Mosul.
[2] Al- Naqib, S.Q., 1980. Geology of Atrush Area, Unpublished M.Sc Thesis, Univ.
of
[3] Boyer, S. E 1986. Styles of folding within thrust sheets, J Struc, Geol, 8, 3-4 325-
340
[4] Csontos, L., Sasvári, Á, Pocsai, T., Kósa, L., Salae, T. M., and Ali, A., 2012.
Structural evolution of the northwestern Zagros, Kurdistan Region, Iraq:
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