Structure analysis of the Azmir–Goizha anticline, north and northeast of Sulaimani city, Kurdistan Region, NE-Iraq
Kamal Haji Karim and Sirwan Hama Ahmad*1
1Department of Geology, University of Sulaimani, Sulaimani City
Published in: journal Journal of Zankoy Sulaimani – Part A (JZS-A), Vol.(16), No.(1).
Abstract
The Azmir-Goizha anticline elongates directly to north and northeast boundary of Sulaimani city, Kurdistan Region, NE-Iraq. The anticline is originally consisted of two main connected anticlines (Azmir and Goizha anticlines) with many smaller anticlines along southwest and northwest limbs. In the studied area, it has the length, width and elevation of about 10, 4 and 1.6 kms (amsl) respectively. It elongates from Weladar village, from southeast to Khamza village at the northwest and it further elongates outside studied area. The anticline is very complex and recently few structural analyses are conducted on it. The present study tries to use the field study and precise stratigraphic analysis to show the new and actual structural setting of the anticline. The results are compared accurately with the results of the previous ones in detail. Structurally, the previous pigy-back thrust imbricated fan is changed to nearly isoclinal detachment fold which detached in the form of either lift-off detachment fold or multi-detachment or multi-detachment faulted. In the core of this anticline the accommodation of the shortening is preserved as second-order folding or second-order conjugate faulting. The competent cover (outer layers) of the anticline is consisting of Kometan and Balambo (its upper part) formations while the plastic incompetent layers are consist of two units. In the core of Azmir and Qaywan anticlines consists of Sarmord Formation while the core of Azmir Bichkola and Naugirdan (or Goizha) anticlines consist of the lower part of Balambo Formation which is deformed as disharmonic buckle folds. The main detachment is occurred in the lower part of Sarmord Formation and inside Jurassic Rocks. All the previous strike slip and reverse faults in the previous studies are refused in the present one. Furthermore, the study recommends excluding the anticline from the Imbricated Zone and including it in the High Folded Zone
Key words: Strucute of Kurdistan, Azmir (Amar) mountain. Stratigraphy of Kurdistan, sedimentary rocks of Kurdistan, Dokan (Dukan) Formation, Kometan Formation, Gulneri Formation,
1-Introduction
The Azmir and Goizha are two connected mountains that located to the north and northeast of Sulaimani city respectively. In the present time the boundary of two mountains are nearly coincide with boundary of city (Fig.1). The two mountains are forming a small northwest-southeast mountain range looking over the city and have important location and beautiful sense, due to which it used as picnic area for local and foreign visitors.
Fig. (1) Geological map of Azmir-Goizha anticlines (modified from Karim et al., 2013)
Structurally, each of the two mountains consists of a large anticline and together is called Azmir-Goizha anticline (AGA). With these two anticlines, the Azmira Bichkola and Haruta anticlines are studied too which are located to the northeast of AGA (Fig.1). These four anticlines (with complementary synclines) contain many parasitic folds in their core and along their limbs. The north western end of the Goizha anticline is dissected by four streams by which it shaped to four pyramidal hills and called Naugirdan hills (Fig.1). Recently several detail studies are achieved on AGA such as Al-Jumaily and Adeeb (2011), Omer (2011) and Al-Hakari (2011).
Historical the development of the anticline was controversial, Lawa (2004, p.213 and 222) in his model for basin analysis of Kolosh Formation showed that the anticline was source area for the latter formation during early Paleocene and called it “Azmer Orogenic belt”. Hakari (2011) showed by correlation chart same idea of Lawa (op ct.) that Azmir-Goizha anticline was uplifted and acted as terrestrial land between Red Bed Series and Kolosh Formation during Paleocene .
In contrast to the above ideas, Karim 2004 and Al-Barzinjy, 2005 concluded that the anticline was not existed during Maastrichtian and Paleocene respectively and its position was covered by marine water in which both aforementioned units are deposited as concurrent and lateral facies changes. Karim et al. (2008) concluded, on the basis of sedimentology and hydrodynamic of the Zagros foreland Basin, that first development of the anticline had occurred during middle Eocene and prevented the influx of the clastic sediments to reach Pila Spi basin. Aziz and Lawa, 2000) called the anticline “Azmir anticlinorium” and Hakari (20011) used the same name too. Ibrahim (2009, p.137 and 143) gave two different ages in two different pages for the first development of the anticline which was the age of Paleocene and Late Eocene.
The aim of the present study is to give completely different ideas about the structure and tectonics of Azmir-Goizha anticline. The study depends on the field work by using hand lenses (10 X and 30 X) and the attitudes of the bedding are measured by compass and plotted on the stereonets. The locations are indicated by GPS on the geological map and three detail geologic cross sections are drawn which show the types, sizes and relations of anticlines with stratigraphy and geomorphology (Figs. 2, 3 and 4). For the geological mapping, the study has depended partly on the study of Karim et al. (2013) who differentiated both Kometan and Sarmord Formations from Balambo Formation for the first time (Fig.2). They also proved the occurrence of the age equivalents of Gulneri (marl and marly limestone) and Dokan formations. Another result of their study is conclusion that the lithology of Kometan Formation and upper part of Balambo Formation are very similar in lithology. All previous proven faults are refused and all other structures at are concluded in the previous studies are discussed and re-studied in detail.
Structure of the Azmir-Goizha anticline (AGA)
The structure of the AGA, as its stratigraphy, is very complex due alternation of competent and incompetent units in addition to sudden facies change in the area. According to tectonic subdivision of Jassim and Goff (2006) it located in the boundary between High and Imbricated Zones. Due to the new geologic mapping and stratigraphic differentiation (by marker beds) of the most recent studies (see Karim et al., 2003), a new accurate structural analysis and modification was possible. In the new geological map three elongate outcrops of Balambo Formation are shown (Fig.1) instead of one of the previous studies (see Omer, 2011, Al-Hakari, 2011; Al-Jumaily and Adeeb, 2011) (Fig.5). These three outcrops are indicator that for three main anticlines (in the studied area) which are surrounded by younger Kometan Formation. From size the outcrop of the Balambo Formation, it can be realized that the central one is the largest one and southwestern the one is smallest of the three (Figs. 3 and 4). Al-Hakari (2011) divided the studied area into four anticlines of Azmar Bechkola, Haruta, Main Azmar and Goizha and he concluded that they are forming piggy-back thrust imbricate fan.
Fig.(2) Geological cross section of Azmir-Goizha anticlines of the present study (see A1—-A2 line in figure 1). (Folds that are smaller than 50 m are not shown).
Fig.(3) Geological cross section of Azmir-Goizha anticlines passing through Weladar village (See B1—B2 line in the figure 1), the minor deformations are not shown.
Fig.(4) Geological cross section of Azmir-Goizha anticlines passing through Khamza village (See C1—C2 line in the figure 1), the minor deformations are not shown.
1-Azmar anticline
It is the largest anticline in the studied area and it elongates for about 91 km and its northwestern and southwestern plunge are located near to Dokan Town and Chanakhchian villages respectively. The anticline has width of 1- 4.5 km and has many local names along its length such as Sara, Daban, Qayiwan, Azmir, Sarjor, Kharajyian Mountains (or anticlines) from northwest to southeast. According to Karim et al. (2013), its core is occupied by Sarmord Formation while Balambo and Kometan Formations cropped out as outer competent rocks. In most places, these two units cover lower and upper limbs respectively. Many smaller parasitic folds exist on the limbs some of which are differentiated in this study (Figs.2, 3 and 4).
Al-Hakari (2011) mentioned that the Azmir is tight fold, but the cross section of this anticline shows, in the present study that it is more or less close to isoclinals fold (Fig.2). This is because the field study showed that the dip angle of the limbs of Azmir anticlines is variable. In some place it is shows double vergen and in others has isoclinal or close interlimb angles. But the mean attitudes of the northeastern and southwestern limbs are 326 /85 and 145/87 respectively with the trend of the fold axis of 325 degrees. These attitudes show that the anticline more resemble isoclinal anticline than close one. The new result does not confirm the naming of the “Anticlinorium” which applied by Aziz and Lawa, 2000) and Hakari (20011) but this anticline is normal anticline in most places.
2-Azmira Bichkola anticline
In the studied area, this anticline is about 1k wide and 3km long and has extent outside the studied Area (Fig. 1). Due to dissection by valley streams, it forms three pyramidal hills and Al-Hakari (2011) mentioned that it is open anticline and has been forked (separated) from Azmir anticlinorium and formed a surface anastomosing pattern of the folds.The present study has inferred that it is independent and nearly straight anticline and its southeastern and northwestern plunges are located at boundary of the Modern Sitak village and 1km to the southeast of the Mokaba Bridge respectively with total length of 9 km. The cores of the anticline is occupied by Balambo Formation not Kometan Formation as mentioned before (Figs. 2, 3 and 4). It consists of more than two smaller anticlines some of which are faulted and show second-order folding and second-order conjugate faulting (Epard and Groshong, 1995, fig. 5). But the mean attitude of the northeastern and southwestern limbs are 320/40 and 148/60 respectively with the trend fold axis of 328.
Fig. (5) Geological map of the studied area, A) Omer (2011) and Al-Jumaily and Adeeb (2011), B) Al-Hakari (2011)
Fig.(6) Schematic detachment folds with alternative shortening accommodation mechanisms. (a) Homogeneous strain. (b) Second-order folding. (c) Second-order conjugate faulting. (d) Duplex. (Epard and Groshong, 1995).
3-Haruta anticline
Al-Hakari (2011) mentioned that Haruta anticline forks from Azmir anticlinorium and forms a surface anastomosing pattern of the fold. The present study has inferred that it is independent and nearly straight anticline. Its northwestern plunges are located far outside the geographical extent of Azmir anticline which extends from Sharsten village (As southeast plunge) to near Gapelon village where its northwestern plunge is located. On the road to Chwarta it has the width of about 200m while it becomes 800m to the northeast of Khamza village (Figs.5 and 7). Its core is occupied by Balambo Formation not Kometan Formation as mentioned in previous studies. This anticline is associated with smaller anticlines but not studied in the paper. It is separated by wide and narrow synclines from Azmira Bichkola and Azmir-Gozha anticlines respectively. Inside the wide syncline Shiranish Formation is exposed while it eroded inside the narrow one. In the southeast of the studied area, the Haruta anticline is close fold while becomes isoclinal at the northwest at 1km northwest of Khamza village (Fig. 4 and7).The attitudes of the limbs are changing from place to place, but the mean attitudes of the northeastern and southwestern limbs are 329/60 and 146/75 respectively with the trend fold axis of 326.
Fig. (7) Haruta and AGA (Azmir-Goizha anticline) directly to the northeast of Khamza Village
Goizha (Maindol) anticline
This anticline is looking over of Sulaimani city from the northeast and its southeastern and northwestern plunges are located to the north of Arbat town and northeast of Kani Mekail village respectively. It has the length and width of 29 km and 500m respectively. In the north of Sulaimani city it dissected (by streams) into four beautiful pyramidal hills known as Naugirdan Hills (Fig. 1). To the east of Sulaimani City between Kazjwa modern village and Arbat town, the Goizha anticline has weak expression on earth due to erosion and intense deformation but it can be indentified easily (Fig.2,3 and 4). Its core is occupied by Balambo Formation and exposed along the anticline axis. The core deformed to accommodate shortening mechanism in the form of homogeneous strain folding and second-order folding (Fig.8). The mean attitude of the northeastern and southwestern limbs are 322/57 and 144/ 75 respectively with the trend fold axis of 325 (Fig.9).
Fig. (8) Disharmonic folding in the intensely deformed core of the first Naugirdan hill (Salta Re hill), B) cross section of the hill with competent beds of Kometan and Balambo (its upper par) formations (orange) and incompetent (core materials) brown lower part of Balambo Formation
Fig. (9) Stereonet of the studied four anticlines
Piggy-back imbrcate thrust fan versus Detachment folds
The definition of the of the imbricate fan (as cite in web sites) is A series of splay faults branching off and ramping sequentially out of the main, deeper floor décollement surface, which spreads the displacement over a large volume of rock. The junction line where the main thrust fault splits into two smaller thrust surfaces is a branch line. The branch points are where the traces of two thrusts meet on a cross-section. The branch points at the floor of an imbricate fan, where two thrusts separate toward the foreland, are called trailing branch points. The merging points of two thrusts joining into one as they are traced toward the foreland are called leading branch points. The youngest splay is the front thrust in a leading fan. In that case, the youngest splay carries the older one “on its back”, which is called piggy-backing (https:// courses.eas.ualberta.ca/eas421/lecturepages/thrust.html.
Goodarzi (2007) gave the following description of detachment fold” According to most authors, a prerequisite condition for the generation of detachment folds is the existence of a high competency contrast between the sedimentary units involved in the folding process. The simplest model therefore consists of a basal incompetent layer acting as a detachment zone, such as salt, overlain by a thick competent unit such as carbonates or sandstones. The basal unit responds in a ductile manner to fold growth, with migration of ductile material towards the core of the anticlines causing down warp of the adjacent synclines. The structure will develop more or less symmetrically depending on the viscosity of the basal detachment: in areas such as Zagros characterized by ductile detachment horizons (Davis, 1985)”.
Oveisi, et al. (2009) mentioned that the detachment folds do not develop at the tip of a propagating ramp, but above the tip of a sub-horizontal detachment at depth. For detachment folds, limb rotation will produce progressive surface tilting, long and gently dipping panels and maximum uplift at the anticlinal crest. He added that the limited width (6–7 km) of the Madar anticline, as compared to the Mand anticline (>16 km), suggests that the detachment is much shallower here than the depth of Hormuz Salt and possibly corresponds to the relatively ductile Gachsaran formation (~2km depth).
The detachment fold is defined asa fold that is formed above a stratigraphically fixed detachment horizon and without thinning in the syncline will, in general, require layer-parallel shortening. A fold grows primarily by limb rotation, not by limb lengthening at constant dip and it needs homogeneous strain or second-order folding or Second-order conjugate faulting or Duplex for accommodation the shortening (Fig.6) (Epard and Groshong, 1995).
Ibrahim (2009) in his detail study of the Zagros Belt assigned Azmir Anticline, during Paleocene and later ages, as thrust sheet which disconnected from below in the lower Jurassic. He assigned Chemchamal and the Bawanoor Anticlines (in the Low Folds Zone) as detachment fold. He added that both are broad, symmetrical anticlines, formed due to the movement of the Upper Fars, Lower Bakhtiari and Upper Bakhtiari Formations on the Lower Fars detachment surface during Pliocene.
Shaw et al. (2005) mentioned the following facts about Detachment folds and stated that it is contractional anticlines that form above one or more basal detachments and has the properties of, 1) Ductile thickening in the core of the fold (Fig.10), which may be governed by distributed brittle deformation or flow, causes amplification of the fold and with no visible thrust ramp. 2) Detachment anticlines grow by limb rotation, often with some lesser component of kink band migration.
According to Fossen (2010) Detachment folds are the folds that the slip is solely along the layering and form where the layers above a detachment shorten more than their substrate and it is commonly found to be undeformed. Detachment folds tend to develop above very weak layers, such as over pressured shales or evaporates, typically concentric folds. He added that the folds form by buckling and the weak layer flows (deforms) to accommodate the geometric difference between the flat decollement surface and the folded layers above. He further added that detachment folds are generally upright and parallel (constant layer thickness), sometimes with box fold geometry and oppositely dipping axial surfaces. A strong viscosity contrast between the folded layer and its surroundings promotes the formation of a series of buckle folds (a fold train).
Ibrahim (2009, p.107) included the Azmir-Goizha anticline in the Imbricated Zone and he assigned this zone as a piggy–back imbricate stack. Latter Al-Hakari (2011) interpreted Azmir anticlinorium (present Azmir-Goizha anticline) as piggy-back imbricate fan that are consisted of four emergent folds, which are superimposed over each other by adjacent listric fault and may be banded together at depth with the blind foreland vergent listric thrust faults(T1, T2, T3, and TB in fig.11) as basal detachment fault. He added that the basal detachment fault is considered to be in Lower Jurassic formations and Upper Triassic (Baluti shale Fn.). He further added that a listric thrust fault emerge in the southwest of Goizha anticline represents the High Zagros Reverse Fault (T4). Al-Jumaily and Adeeb (2011) emphasized role of faulting in development of the Azmir anticline (as four anticlines of Al-Hakari, 2011) and other minor folds and concluded that they are imbricated fan (Fig.11).
Fig.(10) characteristic (A), and forms (B) of detachment folds (Shaw et al., 2005) which can be applied, more or less, on the Azmir-Goizha anticline
Fig.(11) five reserve faults that are associated with piggy-back imbricate fan as the structure of Azmir-Goizha anticline (Al-Hakari, 2011)
Fig.(12) five reverse faults shaped Azmir-Goizha anticline as Imbricate fan (Al-Hakari, 2011 in Al-Jumaily and Adeeb, 2011).
Azmir-Goizha anticline as detachment fold
When the above definitions and characteristics of the piggy-back imbricate fan and detachment fold are applied of the Azmir-Goizha anticline, it belongs to the latter type due to the following characteristics of the anticline.
1-The core of the anticline is occupied by intensely deformed incompetent rocks (marl of Sarmord Formation) and this core contains train of buckle fold which are disharmonic with outer layers of the fold (Kometan and upper part of Balambo Formation) Fig.(2,3,4 and 8).
2-In the exposed core of the Azmir, Azmira Bichkola an d Naugiran anticline there are not fault bend or fault propagation folds (Fig.13). In one case it shows Second-order conjugate faulting (Fig.14) which according to Epard and Groshong (1995) formed due to accommodation of shortening of detachment fold (Fig. 6c).
3- According to Mitra (2003) the detachment folds are generally more symmetric than other fold forms in fold belts, particularly in the early stages of evolution. Unlike fault-bend and fault propagation folds, they commonly display opposite vergence both across and along fold trends (Fig. 2, 3, and 4). Faulting is usually secondary and occurs primarily to accommodate variations in strain with structural and stratigraphic position. The progression of the detachment fold evolution is generally considered to involve a thrusting through the forelimb with increasing shortening (Fig.14). Azmir-Goizha anticline has all these characteristics as shown in the above mentioned latter five figures.
4- In detachment fold the tightness of the fold increase downward this is agree with the all folds of the studied area (Figs.13, 15, 16 and 17).
5- In Zagros Fault –Thrust Belt many authors (Verges et al., 2011, Yamato, et al., 2011, Oveisi, et al., 2009, Sherkati et al., 2005, Davis, 1985, Goodarezi, 2007) have described detachment folds. The latter author mentioned that in Zagros Belt, depending of the level of erosion, very different fold geometries will be observed at surface. Close to the lower detachment, one will observes tight anticlines, with potential internal disharmonic folding, separated by broad gentle synclines, while towards the upper detachment, one will has the impression of tight synclines and broad anticlines.
6- Multi-detachment fold or multi-detachment faulted fold (Mitra, 2003) is the most suitable type of detachment fold for Azmir-Goizha anticline. This is because Balambo (its lower part), Sarmord, Chia Gara and Jurassic formations can perform differentially as multi-detachment for either faulted or unfaulted detachment folds (Figs.2, 3 and 4). Lift-off detachment fold (Shaw et al. 2005) is generally fit fold in the studied area.
The field study don’t aid the Triassic decollement as the only surface of detachment as indicated by Al-Hakari (2011) this is because Karim and Sulaiman (2012) found shallow lateral thrusts in Aqra Formation, 20k to the north of the studied area. This is true for the presence of surfacial ophiolite thrust sheets at 15km to the northeast of the anticline.
7-During the fieldwork the piggyback structure is not found this because there are not thrust sheet in the studied area as can be seen from the geologic map and related cross section (Figs.1, 2, 3 and 4). Piggyback structure is defined as carrying of early thrust sheets in ‘piggyback’ fashion on younger thrusts. In the studied area there are some small thrust faults but they are neither continuous along the strike nor along the dip. They exist in the scale of 5 to 20 meters and they directed toward both foreland and hinterland (see next section).
8-The indication of Chemchamal and Bawanoor Anticlines (in the Low Folds Zone) as detachment fold by Ibrahim (2009) proves that the Azmir-Goizha anticline is detachment fold. This is because, according to Hessami et al. (2001), the deformation front is started as early as end Eocene in the northeast of the Simply Folded Zone and propagated progressively to the southwest, where unconformable contacts are only seen between younger units. Therefore, the progressive folding and deformation is true for whole Zagros area by which simple detachment fold of AGA is complicated by the increase of compression and shortening during the time.
Fig.(13) A) Symmetrical fold in the core of the forth (Hamai Aza) hill of Naugirdan anticline (only northeastern part is shown) in which the tightness increase downwards, B) complete cross section of the same hill show competent (orange) and incompetent (brown) rocks
Fig.(14) Second-order conjugate faulting formed due to accommodation of shortening of detachment fold in Balambo Formation in the core of second hill of Azmira Bichkola anticline.
Fig.(15) Variations in structural styles of detachment folds related to magnitude of shortening, asymmetry, faulting, and the occurrence of multiple detachments with an example for each type of structure (Mitra,2003)
Fig.(16) Detachment chevron asymmetrical folds in Balambo Formation inside the core of Azmir Anticline at 1km north of Khamza village and 15 km to the northeast of Sulaimani City. It can be observed that there are no faulting and the tightening of the folds increase downwards
Fig.(17) small (at the left) and large anticline with northeast vergen inside Little Qayiwan
Village in the Sarmord Formation
Small faults in the studied area
As mentioned before, the studied area contain some small thrust and normal faults but they are neither continuous along the strike nor along the dip. They exist in the scale of 5 to 20 meters and they directed toward both foreland and hinterland (Fig.18 and19). Ali (2008, p.122) has indicated two local thrust faults that cut the crest and southeastern limb of Goizha anticline (Fig. 20).
Al-Hakari, (2011) described Domino like blocks of the normal faults in the northeastern limb of the Haruta anticline and strikes northwest-southeast (Fig.21). He added that such stretching in NE-SW direction might have been dominated during the uplifting stage of the major fold. The same faults are found by Al-Jumaily and Adeeb (2011) at NE limb of the main Azmir anticline and described them as a series of step-like minor normal faultsin the limestone beds of the Kometan formation.
In present study, these faults are re-examined and it is inferred the followings:
1-The faults are neither located in the northeastern limb of the Haruta anticline nor in the NE limb of the main Azmir anticline but it located in the southwestern limb of the Dry Dam (Wshka Bandaw) anticline which is located between Azmir and the Haruta anticlines (Fig. 2).
2- The domino like normal faults are not found because there are not displacements along the adjacent blocks but what found are a set of joints.
3-The gaps at the base of the blocks are not rotational gaps but they are wedges of scree or accumulated soil at the base of the slops (Fig.21).
Fig. (18) Normal fault at 500m downstream of Ali Agha Bridge, southeastern limb of Azmir Anticline
Fig.(19) The only faults that can be observed in the area are small thrusts that have displacement no more than 25meters, A) Hamai Aza hill, B) Kaziwa Valley.
Fig.(20) Faults that indicated by Ali(2008) in the southwestern limb of Goizha anticline
mbricated versus High Folded Zones
Many authors (Buday, 1980, Karim, 2004; Jassim and Goff, 2006, Al-Qayim et al. 2012) indicated the study area in the boundary between High and Imbricate Zones. Recent studies (Ibrahim, 2009, Al-Hakari, 2011, Omer, 2011, Jumaily and Adeeb, 2011) assigned studied area as imbricate fan which means that the studied area is part of Imbricated Zone. Lawa et al. 2013, p.79) have clearly indicated Azmir-Goizha anticline in the Imbricated Zone (or Zagros Imbricated Zone) as they put its southern boundary to the south of the anticline. In the present study no sign of imbrications is found as appear from figures (2, 3 and 4). Therefore it is better to put Azmir-Goizha anticline in the High Folded Zone instead of Imbricated Zone.
Fig. (21) A set of domino like blocks in the southwestern limb Haruta (Qula Rash) anticline
These faults rotate the blocks, the small gaps (red circles) occur below the synthetic fault blocks (Al-Hakari, 2011).
Large faults in the studied area
Many of sinistral strike slip faults in Azmir anticlinorium trended NE-SW were detected and labeled as (ss1, ss2, ss3, ss4, and ss5) by (Al-Hakari, 2011, Omer, 2011) and the displacement along these faults ranges between (50-70 m) measured from the horizontal shifting in the lithology. All the five strike slip faults that are drawn and found by the latter two authors are not found in the present study as can be seen from the axis of the anticlines in the geological map of the area (Fig.1). On the map, it is clear that there is neither traversal shift in the elongation of the outcrops nor in the axes of the three anticlines (Fig.1). Additionally the locations of these faults are checked on outcrops in the field and lateral shifts were not found (Fig. 18 and 19).
The same thing is true for five thrusts (or reverse) faults that are found and drawn in the figures (5, 11 and 12) by the above latter two authors. The shortening by folding that is calculated for the formation previously is must be checked again due to result of the present study which changed the geological map of the area and introduced new formations. The present study expects that most of the shortening of Kometan and Balambo Formations are occurred due to softness of the underlying Sarmord Formation not Triassic formations. The Gulneri formation, as soft rocks, acted as local detachment surface for Kometan Formation shortening.
High Zagros Reverse Fault that is drawn by Ibrahim (2009) and Al-Hakari (2011) is not found too in the studied area which is supposed to be located in the northern and northeastern boundaries of Sulaimanyia city beneath the modern villages such German, Kaziwa and Barzayiakani Azmir in addition to Kurdsat Satellite TV center. Al-Qayim et al. (2012, p.112) have indicated it near the crest of the Azmir anticline. About this fault, the above three authors have cited the following three paragraphs about this fault respectively:
“It is a NW–SE trending longitudinal listric fault (transformed into reversed displacement) which separates the Zagros Imbricate Zone from the High Folds Zone of the Zagros Foreland Folds Zone. It is considered as a deep basement fault in Iran because along it, in various places, the Hormuz Salt intrudes and reaches the surface (Mobasher, 2007) and there is some seismic activity with strike slip focal mechanism solutions (Aziz Zadeh, 1997). The HZRF is an active fault since the Permian and to the Recent (Bahroudi and Talbot, 2003). It is a 65°NE dipping active major forethrust fault which is expressed on the surface as a Balambo and Azmir anticlines. The more competent Balambo and Kometan formations were thrusted along the HZRF over the low elevated incompetent rocks (Shiranish and Tanjero formations. The HZRF has been displaced dextrally in the Halabja-Said Sadiq area due to the effect of the
Dextral strike slips N–S trending Khanaqin Fault”.
“This is a NW–SE trending longitudinal listric fault which separates the Zagros Imbricate Zone from the High Folded Zone of the Zagros Foreland Fold Thrust Belt. It is considered as a deep basement active fault since the Permian to the Recent (Bahroudi and Talbot, 2003). The more competent Balambo and Kometan formations were thrusted along the fault over the low elevated incompetent rocks (Shiranish and Tanjero formations). The fault extended from SW of Goizah anticline passing through the overlapping area between main Azmar and Surdash anticlines to the NNW”.
“The NW-trending “High Zagros Reverse Fault” separates the Zagros Imbricate Zone from the Zagros Folded Zone. It is interpreted as a deep basement fault in Iran because it is associated with outcrops of Hormuz salt intrusions (Mobasher and Babaie, 2007), and there is some seismic activity with strike-slip focal mechanism solutions (Aziz Zadeh, 1997). The fault has been active since Permian time (Bahroudi and Talbot, 2003). In northeast Iraq, it dips 65°NE-and is clearly expressed on the surface as an axial fault along the Balambo and Azmur anticlines (Ibrahim, 2009). The more competent Balambo and Kometan formations were thrusted along the fault over the low-elevated incompetent rocks of the Shiranish and Tanjero formations. The fault has been displaced dextrally as in the Halabja-Said Sadiq area due to the effect of the dextral strike-slip NS trending longitudinal faults (Ibrahim, 2009)”.
Another large fault is the Khanaqin strike slip fault (Ibrahim,2009, p.149) or Khanaqin longitudinal fault (Al-Qayim et al. 2012) which, according to former auther, it trends toward south at 3km and 12km to the east of Chwarta town and Sulaimani city respecticly (Fig.24). If this tend is true, it must passes near the southeastern end of the studied area where the Lower (Sarmord and Balambo formations) and Upper (Kometan and Gulneri formations) Cretaceous rocks are croping out. Neither Upper nor Lower Cretaceous outcrps show the expression of this fault. Karim(2006) studied a normal fault that passes nearly 5km to the east of Chwarta town but it does not reach the studied area and terminated near the northwestern plunge of the Ashkawta Rash (Dokanian) anticline. This normal fault has the expresion in the outcrops of Early and Late Cretaceous rocks.
Fig.(22) the valley between 3rd and 4th Naugirdan hill where previously mentioned to be site of sinistral strike slip fault but there no fault is fond in the presnt study (The photo looks SW)
Fig.(23) The location of the ss4, ss2 ss3, and ss5 sinistral strike faults of Omer, (2011) and Al-Hakari, (2011) (see figure 2) which are not found in the present study
Fig. (24) Location of the Khanaqin fault (Ibrahim, 2009)
Conclusions
Thos study has the following conclusions
1-The core of the Azmir Anticline is occupied by Sarmord formation not Balambo Formation as concluded in previous studies.
2-The previous piggy-back imbricate fan of Azmir-Goizha anticline is changed to Multi-detachment fold.
3- The five strike slip faults that are indicated in the previous studies are not found in this study. This is true too for the five thrust (or reverse) faults that are indicated in the previous studies.
4- Domino like synthetic fault blocks of the previous studies are not found and proved to be joints.
5- The main Azmir anticline is isoclinals fold while the other three smaller ones are close folds.
6- Many small thrust and normal faults are found but they are of scale tens of meter and don’t coincides with previous ones.
7-it is more suitable to put the Azmir-Goizha anticline inside High Folded Zone than imbricate Zone as no imbrications found in this study.
References
Al-Barzinjy, S. T. M., 2005. Stratigraphy and basin analysis of Red Bed Series from northeastern Iraq-Kurdistan Region. Unpublished Ph.D. thesis, University of Sulaimani University, 159p.
Al-Jumaily, I.S. I. and Adeeb H. G. M. 2011. Some structural characteristics of Azmar Anticline – NE- Iraq, Mineral Res. Expl. Bull., 143, 37-52, 2011.
Al-Hakari S.H.S., 2011. Geometric Analysis and Structural Evolution of NW Sulaimani Area, Kurdistan Region, Iraq 309p.Unpublished PHD Thesis University of Sulaimani.
Al-Qayim, B., Omer, A. and Koyi, H. 2012. Tectonostratigraphic overview of the Zagros Suture Zone, Kurdistan Region, Northeast Iraq, GeoArabia, Vol. 17, No. 4, p.109-156.
Ali, S. A.2008. Geology and hydrogeology of Sharazoor-Piramagroon basin in Sulaimani area, Northeastern Iraq. Unpublished PhD. Thesis, University of Bilgrad, Sirbia, 330pp.
Aziz, B. K., Lawa, F. A., and Said B.M. 2000. Sulaimani Seismic Swarm during spring 1999, NE Iraq. Journal of Zankoy Sulaimany.Vol.4, No.1.pp.87-100.
Aziz Zadeh, M., 1997, Structural setting of the Qatar-Kazerun fault in theZagros fold and thrust-belt: a structural model. Master thesis, Shahid Beheshti University, Tehran, Iran, 282p. (in Persian).
Bahroudi, A. and Talbot, C. J., 2003. The configuration of the basement beneath the Zagros Basin, Journal of Petroleum Geology, 26, 257-282.
Buday, T. 1980. The regional geology of Iraq, Stratigraphy and paleogeography, Dar AL-KuttibPublication House. University of Mosul, Iraq, v. 1, 445 p.
Davis, D. M., and Engelder, T., 1985, The role of salt in fold-and-thrust belts: Tectonoph., v.119, p. 67-89.
Epard J. L. and Groshong Jr. R.H. 1995. Kinematic model of detachment folding including limb rotation,fixed hinges and layer-parallel strain Tectonophysics 247, p.85-103.
Goodarzi, M. H. H.2007. Structure of the Chenareh Anticline in Lurestan, Zagros: role of gravity in folding style, Master en Geología Experimental, Universitat de Barcelona, Group of Dynamics of the Lithosphere (GDL), Institut de Ciències de la Terra “Jaume Almera”, CSIC, Barcelona.
Hessami, K., Koyi, H. A., Talbot, C.J., Tabasi, H. and Shabanian, E., 2001. Progressive unconformities within an evolving foreland Fold.Thrust belt, Zagros Mountains, Journal of the Geological Society of London, 158, pp.969 -981.
Fossen, H. (2010) Structural Geology, Cambridge University Press, 463p.
Jassim, S. Z. and Goff, T., 2006. Phanerozoic development of the northern Arabian Plate, In: Jassim S.Z., Goff, J. C., Geology of Iraq, publication of Dolin, Prague and Moravian Museum, Brno, 341p
Ibrahim, A. O. 2009. Tectonic style and evolution of the NW segment of the Zagros Fold – Thrust belt, Sulaimani Governorate, Kurdistan region, NE- Iraq. Unpublished Ph D thesis, University of Sulaimani, Collage of Science, 187p.
Karim, K. H., 2004. Basin analysis of Tanjero Formation in Sulaimaniya area, NE-Iraq. Unpublished Ph.D. thesis, University of Sulaimani University, 135p.
Karim, K.H., Salih A. O and Ahmad, S. H. 2013.Stratigraphic Analysis of Azmir-Goizha anticline by Nannofossils. Journal of Zankoy Sulaimain (JZS), Part A, Vol.15, No.2 (in presss).
Karim, K.H. Al-Barzinjy S. T. and Ameen, B., M. 2008. History and Geological Setting of Intermontane Basin in the Zagros Fold-Thrust Belt, Kurdistan Region, NE-Iraq. Iraqi Bulletin of Geology and Mining Vo.4, No.1, P. 21-33.
Karim K. H. and. Sulaiman S. H.2012. Origin of lateral thrust in Mawat Area, Kurdistan, NE-Iraq .Petroleum and Mineral Resources 183, WIT Transactions on Engineering Sciences, Vol 81, WIT Press.
Lawa, F. A., 2004. Sequence stratigraphic analysis of the middle Paleocene –Middle Eocene in the Sulaimani District(Kurdistan Region). Unpublished Ph.D. thesis, University of Sulaimani.
Lawa, F. A., Koyi, H. and Ibrahim, A. 2013.Tectono-stratigraphic evolution of the NW segment of the Zagros fold-thrust Belt, Kurdistan, NE Iraq. Journal of Petroleum Geology, Vol. 36.
Mitra, S.2003.A unified kinematic model for the evolution of detachment folds. Journal of Structural Geology 25 (2003) 1659–1673.
Mobasher, K., 2007.Kinematic and tectonic significance of the fold and fault related fracture systems in the Zagros Mountains, Southern Iran, Ph.D. thesis, Georgia State University, USA, 123 p.
Mobasher, K. and H. Babaie 2007. Kinematic and tectonic significance of the fold and fault relatedfracture systems in the Zagros Mountains, southern Iran. Tectonophysics, v. 451, p. 156-169.
Oveisi, B., Lave, J., van der Beek, P., Carcaillet, J., Benedetti, L. and Aubourg, C. 2009.Thick- and thin-skinned deformation rates in the central Zagros simple folded zone (Iran) indicated by displacement of geomorphic surfaces. Geophys. J. Int. Vo.176, pp. 627–654.
Omar, A. A. 2011. Analysis and Interpretation of Minor Folds Developed in the Cretaceous Formations within Azmir Anticlinorium, in a Part of Iraqi Zagros Fold and Thrust Belt, Suliyamania District, Northeastern Iraq. Journal of Basic and Applied Scientific Research. Vol.1 (10) p.1490-1497.
Shaw, J. H., Connors, C. and Suppe, J. (eds.) 2005. Seismic interpretation in contractional fault- related fold, An AAPG Seismic Atlas, Study in Geology, no.53, p.59 p
Sherkati, S., Molinaro, M., de Lamotte, D. F. Letouzey, J. 2005.Detachment folding in the Central and Eastern Zagros fold-belt (Iran): salt mobility, multiple detachments and late basement control .Journal of Structural Geology, Volume 27, Issue 9, Pp. 1680–1696,
Verges, J., M. G. H. Goodarzi, H. Emami, R. Karpuz, J. Efstathiou, and P. Gillespie, 2011, Multiple detachment folding in Pusht-e Kuh arc, Zagros: Role of mechanical stratigraphy, in K. McClay, J. Shaw, and J. Suppe, eds., Thrust fault-related folding: AAPG Memoir 94, P. 69–94.
Yamato P, Kaus B. J.P., MouthereauF, and Castelltort, S. 2011 Dynamic constraints on the crustal-scale rheology of the Zagros fold belt, Iran. Geology, vo.39, No. 9, pp.815-818.
