Record of Khurmala Formation (Late Paleocene-Early Eocene) in the Sulaimani Governorate, Kurdistan Region, Northeast Iraq

 Record of Khurmala Formation (Late Paleocene-Early Eocene) in the Sulaimani Governorate, Kurdistan Region, Northeast Iraq

Kamal Haji Karim , Hyam Saleh Daoud  and Abdulla Rashid Husein Kuradawy

Accepted for publication in : Iraqi Geological Journal (IGJ)

 

Abstract

The present study focuses on the field, petrography and stratigraphic analyses of a thick and sparsely fossiliferous dolomitic limestone succession in the west, north and northwest of Darbandikhan town from Sulaimani governorate. The succession thins toward northwest and east and located in the stratigraphic position of and Khurmala (or Sinjar) Formation (Late Paleocene-Early Eocene) between Kolosh and Gercus Formations at the base and top respectively. The Khurmala Formation is a lagoonal crystallized limestone, dolomite with interbeds of different clastic rocks. It also contains occasional occurrence of gypsum and rare gastropods, miliolids and algae in some beds. Previous studies found the formation and described in Duhok, Kirkuk and Erbil Governorates while in Sulaimani area it not proved until now. The present article studied four different sections of succession (previously and indicated as Sinjar Formation) and correlated them stratigraphically with each other and with Khurmala Formation in its type section in the well K-114. The study showed that these sections are belongs to Khurmala Formation. The sections reveal many evidences and signs of the occurrence of Khurmala Formation in between Kolosh and Gercus Formations. These signs are occurrence of 160 m of dolomitic limestone (80%) with beds of sparsely fossiliferous limestone (18%) and conglomeratic limestone (2%) in Zawali section on Shameran Mountain. The fossiliferous intervals contain lagoonal sparse and small miliolids, gastropods, pelecypods green and red algae. The formation laterally changes to Kolosh (in Mirade section) or partly to Sinjar Formation (in Dara Rash section). In the Mirade section neither Sinjar nor Khurmala Formation are deposited and yellow marly limestone, sandstone and few beds of conglomerate occupy their stratigraphic position.

Key Words: Khurmala Formation, Sinjar Formation Paleocene-Eocene stratigraphy, Zawali Mountain, Darbandikhan, Iraqi Geology.

1. Introduction

    The present study aimed to study the origin of a thick and sparsely fossiliferous dolomitic limestone succession (Hereafter, this study refers to it as “dolomitic succession”) in the west, north and northwest of Darbandikhan town from Sulaimani governorate. The succession is located in the stratigraphic position of Khurmala (or Sinjar) Formation (Late Paleocene-Early Eocene). Khurmala Formation (Paleocene-Lower Eocene) was first described by Bellen et al (1959) in the Kirkuk-114 well where about 185m thick. According to same authors, the formation consists of dolomite, suboolitic in parts, and finely recrystallized limestone.  The chemical limestone probably interfingering strongly with material from the Kolosh Formation, which is containing detrital chert, flint, radiolarite, and green rocks of silt and sand size. The above authors have further added that anhydrite, which is probably secondary, occurs occasionally and fossils are obliterated by recrystallization and dolomitization.

The Kolosh Formation underlies this unit and it grades into the Khurmala Formation through interdigitation. The overlying formation is Avanah Formation, which has unconformable, perhaps erosional contact (Bellen et al, 1959). In well Chemchemal-2, Ditmar and Iraqi-Soviet Team (1971) noticed that the formation is composed of recrystallized limestone, with occasional argillaceous bed and beds of anhydrite and gypsum. According to Jassim and Goff (2006), the formation has deposited in a restricted lagoonal environment. Fossils mostly dwarf and obliterated by crystallization. The aim of this study is to record the new outcrops of the Khurmala Formation in Sulaimanyiah  area and indicating  more accurate stratigraphic position which according to Buday(1980) has slight obscure stratigraphical position .

In addition to above studies, there are many others ones that are concerned with Khurmala Formation. These studies are  such as: Al-Surdashy (1988), Al-Qayim and Nisan (1989), Al-Berzanji (1989); Al-Sakry (1999); Al-Surdashy and Lawa (1993), Al-Qayim (1995),  Lawa (2004), Al-Sakry (2006), Ahmed (2008), Jaff (2008), Salih and Abdullah (2009), Salih  (2010) and Salih (2013), Omer et al., (2014). These studies have studied petrography, facies and environment of the Sinjar and Khurmala Formations but none of them has mentioned occurrence of Khurmala Formation in Sulaimani Governorate. Three of these studies have included one chapter of sequence stratigraphy such as Lawa (2004.), Al-Sakry (2006) and Jaff (2008).   

1.2. Methodology

     The study of the dolomitic succession depends on the fieldwork and microscopic studies. During the fieldwork, the stratigraphic units are differentiated and four different sections are selected for the study on the left and right side of the Darbandikhan lake (or Sirwan fault) (Fig.1). In the field, the lithology of the section are inspected and described from the base to the top of the sections by the eyes and hand lens. From the sections, the authors took 35 samples according to the change of the lithology for the lab studies. The names and locations of the sections are   Zawali, Dari Haji Khidir, Mirede and Dara Rash Sections which are located  at  the attitudes and longitudes of (35o 06’  45.06” N  45o 49’ 25.23” E) ,(35o 14’ 51.81” N  45o 46’ 59.98” E),(35o 14’  39.09” N  45o 41’ 21.32” E) (35o 21’  53.44” N  45o 29’ 20.7” E) respectively. These sections are correlated mutually and with the type section of the Khurmala Formation in K114 well in Kirkuk oil field. The studied sections are plotted on topographic map and the Google earth images. The previous geological map is modified to show the location and distribution of the stratigraphic units that are under consideration

In the lab, the thin sections are prepared from the samples and they are studied under stereo, and petrographic microscopes for indication of their lithology and fossils of content the samples are studied. The thin sections preperation and their petrographic study are achieved in the laboratories of Department of Geology, University of Sulaimani.

 1.3. Geological setting

The studied area is located in the Kurdistan Region, northeastern Iraq, about 40 km to south and the southeast of Sulaimaniya City which include the area around Darbandikhan and Zarayen towns (Fig.1).The area is located in southeastern boundary of Sharazoor plain and Darbandikhan Lake is nearly occupies center of the area. The area located inside the High Folded Zone as a part of Western Zagros fold-thrust belt.  Many authors such as Buday and Jassim (1987), Lawa (2004), Jassim and Goff (2006), Ibrahim (2009), Aqrawi et al. (2010),  Al-Qayim et al. (2012) and  Lawa et al. (2013)  mentioned  passing of Khanaqin  (or Sirwan) fault  through the studied area.   Karim et al. (2016) has studied the area on the both side of the fault and conclude that are no stratigraphic and structural surface expressions of the fault. They found that the curvature of the anticlines and wideness of the synclines are attributed to deposition of thick and massive succession of conglomerate of Upper Bakhtiari Formation in the north and south of the Darbandikhan dam.

There are two main mountains (anticlines) series with the trends of northwest southeast and have many local names. The southern one is elongated from Iranian border at the southeast of Darbandikhan town toward northwest and south of Sulaimani city.   These mountains are called Sartak-Bamo, Zimnako or Khushk, Birkey, and Baranan mountains. The northern one is called Zawali (or Shameran), Bard Asin (or Ahmad brnaw) and Shafa Rash Mountains and two of the studied sections are located on the northeastern side (limb) the northern series. In some places, the southern and northern series are formed from two limbs of large anticline and its core is eroded forming a strike valley (or subsequent valley). In the area extensive outcrops of the Sinjar or Khurmala, Gercus and Pila Spi formations are exposed along the two structures (Figs.1 and 2).

   The area is a part of the Sirwan valley which collects runoff from most parts of northeast of Kurdistan region into Darbandikhan lake (Fig.1). The Sirwan river valley has broad bottom with gentle sides and classified as Consequent River, which meets with many subsequent tributaries. In the area, Sirwan River has highly meandering course which controlled by local structure, lithology and coarse accumulation of alluvial fan sediments.

Most areas of the valley consist of local plains, which are hilly and mostly sloping gently toward the Diala River. These plains are mainly covered by sporadic small and large blocks of limestone of Sinjar, Pila Spi Formations and Oligocene rocks such as the area around Darbandikhan town. Other parts of the areas are covered by badlands that consisted of numerous small valleys and canyons, which are deep and steep, sided.

1.2.1. Stratigraphy

In all sections, Kolosh and Gercus Formations bound the dolomitic succession from base and top respectively. The Sinjar does not occur in the studied sections but its position occupied by the dolomitic succession but it gradually and laterally changes Sinjar Formation outside the studied area toward Baranan  and Sartak Bamo mountains at  west and southeast of the studied area.  The study specifies the main characteristic of these two formations in the below sections.   

1.2.1.1. Kolosh Formation (Middle Paleocene-Early Eocene)

The formation consists of black to grey marl, sandstone and thin beds of conglomerate and its thickness reaches, in the studied area, about 400m while its thickness in its type locality, and according to Bellen et al (1959) is 700 meters. It is exposed in the core of the anticline such as Birke, Zimnako and Zawali. Due to the softness, it is intensely deformed by upwards flow and accumulation in the cores of the above anticlines. On outcrops, the softness has driven many slipped blocks of Sinjar Formation on Kolosh Formation along the northwestern limbs of the above-mentioned anticlines. Its boundaries are gradational with both Sinjar and Tanjero Formation (Fig.3).

Khurmala fig 1Fig.1 Google terrain image shows the location of the studied section,  Zawali, Dari Haji Khidir, Mirede and Dara Rash Sections (at attitude and longitude of (35o 06’  45.06” N  45o 49’ 25.23” E) ,(35o 14’ 51.81” N  45o 46’ 59.98” E),(35o 14’  39.09” N  45o 41’ 21.32” E) (35o 21’  53.44” N  45o 29’ 20.7” E) respectively.

 

1.2.1.2. Sinjar Formation (Late Paleocene-Early Eocene)

   At the southern boundary of the studied area, this formation   mainly consists of about 40meters of grey to milky massive to well bedded detrital and biogenic limestone. It has gradational contact with both Kolosh and Gercus Formations. In the studied area, it only exposed on the both limbs of the Zimnako, Berki and Baranan anticlines. Its main fossil content is nummulites, alveolina and discosyclina with rare coral, green algae, pelecypods and gastropods. On the both side of the Khanaqin fault, the formation is relatively thin and has about 10-40 m thickness and the limestone occasionally associated with conglomerates (Karim et al., 2016). In the studied sections, it replaced by the dolomitic succession that consists mainly of dolomitic limestone and the fossils of previously assigned Sinjar formation are not present. The present ones are similar to those that are present in Khurmala Formation.

Khurmala fig 2Fig. 2 a) A location map of the studied area shows five tectonic zones (Buday, 1980), b) Geological map of the studied area shows the location of the two sampled sections (modified from Sissakian, 2000)

Khurmala fig 3Fig. 3 Kolosh and Khurmala Formations on the Zawali Mountain or anticline

 1.2.1.3. Gercus Formation

In the studied area, the thickness of this formation is variable from place to another; the maximum thickness is located near the Darbandikhan dam and near Mirade village, where reaches more than 200m. It is composed of red claystone, sandstone and lenses of conglomerate (Fig.4). Its boundary is gradational with underlying Sinjar Formation while it is unconformable with the overlying Pila Spi Formation as there is a bed of conglomerate between the two formations, which is about 3meters thick and described by Ameen (2006).

In the studied area, on Zawali anticline, the formation shows more carbonate constituent than that of Mirade as half of its lithology consist of marl and marly limestone with few beds of fossiliferous limestone (Fig.5) and the other half consist of conglomerate and sandstone with few beds of red claystone. According to Khanaqa and Karim (2015), it rapidly changes to dolomitic limestone and marly limestone of the Khurmala Formation toward southwest. This change is due to passing from clastic dominated coastal area to carbonated dominated inner shelf of Eocene Foreland basin.

Khurmala fig 4Fig.  4 Alternation of red claystone, sandstone and marl of Gercus Formation at 200 m of north of Mirade village.

Khurmala fig 5Fig.5 Marl and marly limestone succession inside Gercus Formation above the studied section on Zawali anticline

 

2. Result   

 2.1. Origin of the dolomitic succession

      For finding the origin of the dolomitic succession, the study tries to find its stratigraphic affinity especially about 80% of its thickness comprised of unfossiliferous dolomitic limestone and this property is not characteristics of Sinjar Formation. Therefore,  it is more likely belongs to Khurmala Formation and  for proving its affinity, four sections are described, sampled and correlated  as shown in the below sections.

2.1.1. Zawali (Shameran) mountain section

      This section is located on the Zawali anticline about 3 km to the southeast of Shameran village on the left side of Darbandikhan lake (Sirwan fault) at the latitude and longitude of 35o 06’ 45.06” N 45o 49’ 25.23” E respectively (Fig.6). In this section, Sinjar Formation is changed laterally to Khurmala Formation that is the topic of the present study. It has about 170 meters of the thickness and does not contain the characteristic lithology and fossils of Sinjar formation. The section is described in the field by eyes and hand lens and 14 samples are taken which are selected according to the change of lithology (lithoclasts, bioclasts fossils and allochems).

2.1.1.1. Sample description of Zawali section

The sample numbers begin with Capital letter (Z) which refers to Zawali Mountain in the northeast of Darbandikhan town.

 Z1: Alternation of friable thin beds of light brown calcareous shale and sandstone.

Note:  Between Z1 and Z2 there is a transitional boundary between Kolosh and Khurmala Formations, which is represented by three meters of massive, light brown to buff dolomitic sandy limestone.

Z2 and Z3: Buff massive to well bedded, flintery, vugy marly limestone, recrystallized and dolomitic no signs of fossils.

Z4: Light gray, well-bedded limestone, contains abundant white spots, which are dasyclacean algae (Fig.7 and 8).

Note: between Z4 and Z5 there is a partially covered interval about 8 thick but it may be marly limestone, sample is not taken in this interval.

Note: There is a 50 cm thick conglomeratic limestone, which contains gravel of chert.

Z5: Well bedded to massive, light gray, highly recrystallized, vugy and flintery dolomitic limestone. It contains sporadic shells of pelecypod and gastropod with different gray spots which may ghost of forams.

Z6: Highly recrystallized gray dolomitic limestone with evenly distributed oval vugy that may represent mold of dascycladacean green algae.

Z7: Well bedded gray fossiliferous limestone contains small milliolids, rare nummulites, and red algae clasts.

Z8, Z9 and Z10: Well bedded gray to brown fossiliferous and detrital limestone contains miliolids and other forams.

Z11 and Z12: Different colors (black, gray and yellow) dolomitic limestone, it is soft and porous, the last 2 m contain forams and red algae.

Z13: Well bedded gray to light yellow fossiliferous limestone, it contains pelecypods and gastropods (Fig.9), milliolids, red algae with a bed of conglomerate (20 cm) at the top.

Note: Above Z13, the transitional boundary begins between the Khurmala and Gercus Formations. The boundary consists of alternation of marl, shale, sandstone, and conglomerate with several beds of marly limestone. In this area, the Gercus formation has not  typical lithology as it  contains no red claystone.

Khurmala fig 6Fig. 6 The studied section on the northeastern limb of Zawali (Shameran) anticline

2.1.2. Dari Haji Khidir section

       This section is located on the right side of the Darbandikhan Lake (Sirwan or Khanaqin fault) on the northern side of the  paved road between Qalbaza and Kani Bardina at 8 km to the southeast of Zarayeen town (Fig.10 and 11). Its GPS location coincides with the latitude and longitude of 35o 14’ 51.81” N  45o 46’ 59.98” E respectively.  The section consists mainly of 16 m of vugy, partially recrystallized   dolomitic and chalky limestone with few thin beds of algal and detrital sandy limestone. Ten samples   are taken from this section and all thin sections are barren of fossils except for ghosts of plant debris and some detrital carbonate grains.  Toward west and at 200m to the north of Mirade village; it thins out and become zero in thickness (Fig.12). At this placed it is represented by about 30 m of light grey to yellow succession of clastic sediments of sandstone marl and marly limestone with few bed of conglomerates  (see figure 16 Mirade section).

Khurmala fig 7  Fig. 7 Dasycladacean green algae on the Zawali anticline inside Khurmala Formation at 60-65 intervals, a) Under stereoscope microscope, b) under polarizer microscope, XP, X10.S.no.Z4

Khurmala fig 8Fig. 8 Stratigraphic column of the studied section on the northeastern limb of Zawali (Shameran) anticline 

Khurmala fig 9Fig. 9 a) 10 cm thick conglomeratic limestone bed inside Khurmala Formation.  b) Gastropod and pelecypod in the upper part of the formation.

Khurmala fig 10Fig. 10 Dari Haji Khidir section shows  Khurmala Formation (16 m thick) between Qalbaza and Kani Bardina villages at latitude and longitude of 35o14’  51.81” N  45o 46’ 59.98” E respectively. It consists of vugy, chalky and partially recrystallized dolomitic limestone and marly limestone.

Khurmala fig 11Fig. 11 Stratigraphic column of Dari Haji Khidir (Khurmala Formation) between Qalbaza and Kani Bardina villages

Khurmala fig 12Fig.12 Light grey to yellow succession (30 m) of sandstone marl and marly limestone of Mirade section. It represents equivalent of Khurmala Formation according to lateral tracing by the authors.

 

 2.1.3. Dara Rash valley section

    This section is located at 25km to the south of Sulaimani City and   run along the paved road between the latter city and Qaradagh town on the Baranan mountains. The sampled section is located in the Dara Rash valley   at the top of Sinjar Formation   and its thickness is about 60 meters (Fig.13).

      As mentioned previously, near Mirade village the Sinjar or Khurmala Formation is disappear and replaced by clastic sediments. Toward the east of the village, Sinjar Formation is gradually appearing again and thickened along the latter mountain. In the Dara Rash valley both Sinjar and Khurmala, exist between Kolosh and Gercus Formations. The Khurmala Formation consists of dolomitic limestone and marly limestone with several beds of sandstone and conglomerate at its upper parts but it does not contain gypsum and anhydite. This succession contains lagoonal fossils such as miliolids and other dwarfed fossils with detrital chert and brown plant debris (Fig.14).   

Khurmala fig 13Fig. 13 Dara Rash section at attitude and longitude of  35o 21’  53.44” N  45o 29’ 20.7” E.

Khurmala fig 14Fig. 14 Dara Rash section contains A) plant debris and B) chert detrital grains (extraclasts) sample no.5 and 7.  

3. Discussion

The formation is found and described previously in the Duhok and Arbil Governorates while in Sulaimani Governorate not proved previously. Conversely, during fieldwork in the southeast and southwest of the Sulaimani Governorate, the authors found many evidences and signs that show occurrence of this formation in the stratigraphic position between Kolosh and Gercus Formations on the Zawali (Shameran) mountains (anticline) at 15 km northeast of Darbandikhan Town. In the same stratigraphic position, it is found at the southern boundary of the Sharazoor plain between Qalbaza and Kani Bardina villages (Fig.6 and 10). 

These signs are occurrence of about 160 meter of unfossilifrous dolomitic limestone (80%) (Fig.15), fossiliferous limestone (18%) and conglomeratic limestone (2%) according to percentage of thickness of the section. The second evidence is neither reefal facies (coral and algal build up) nor forereef facies (nummulite forams) are found in all four studied sections. The third evidence is presence of sparse and small miliolids (Fig.16-9), gastropods, pelecypods (Fig.9b), green algae and rare red algae (Fig. 16) which mentioned by Bellen et al. (1958) to be present in its type section.

The forth evidence  is the occurrence of Khurmala Formation in a bore holes in the nearby areas such as in well Chemchemal-2 where it is composed of recrystallized limestones, with occasional argillaceous bed, and beds of anhydrite and gypsum (Bellen et al. 1958).

Karim (1997), in Sartak Bamo area about 25 km to the southeast of Darbandikhan town, cited the first possible occurrence of the formation  and referred to a succession of marly limestone (about 20 m thick) as Khurmala Formation above Sinjar Formation. The latter study further found Gypsum nodules and dwarfed fossils in it. Lawa (2004) refereed to similar succession with gypsum nodules on the southwestern limb of Sagrma (or Sagerma) anticline and he assigned it as new formation and called it “Sagerma Formation”. The   name of this new formation is mentioned by Ameen (2008), Lawa and Albayati, (2008) and appeared in Cenozoic stratigraphic column of Middle East by Al-Husseini (2008).

      The lagoonal environment in all described section is clear from lithology and fossils content, furthermore, each of the middle and upper part of Zawali, Mirade and Dara Rash sections contain thin or medium beds of conglomeratic limestone that contain sporadic chert gravels. This means that the basin of formation was connected with a source area and intermittently had supplied by freshwater. It is possible that the lagoon is bordered and separated from open see at the south west (Jaddala open basin) by a barrier. Karim et al (2008) considered this barrier as local uplift in the Foreland basin after deposition of Kolosh Formation during late Paleocene (Fig 17).

       According to descriptions of previous sections, neither Khurmala nor Sinjar are   present in   Mirade section and its stratigraphic position is occupied by clastic succession about 30 m thick. The reason for non-deposition of Khurmala (or Sinjar) Formation is, according to field evidence, is resulted from two factors. The first is during history from Maastrichtian to Pliocene Darbandikhan and Sirwan valley was a subaerial or submarine paleo depression for clastic discharge during deposition of Tanjero, Kolosh, Sinjar, Gercus, Lower Fars, and Upper Fars and Bakhtiary Formations.

   During deposition of these formations, the Sirwan valley (including Merade village) was more clastic dominant than other area of the same tectonic position. This type of paleo-depression is shown in paleogeographic model of Paleocene -Eocene by Karim et al (2008) (Fig.17B). The second factor is that the Mirade is more close to the coastal area during Paleocene and Eocene; therefore, the clastic is more deposited than other areas to the south. The evidence for this factor is low thickness of both Khurmala (18m) and Pila Spi Formation (12m) at the area between  Qalbaza and Kani Bardina villages (Fig.1 and 2).

Khurmala fig 15Fig. 15 most of the thickness of the studied section comprised of dolomitic limestone and dolomite, a) interlocking rhombs of dolomite crystals,  PPL, 150X, normal light, s.no. Z6, Zawali section, b) isolated dolomite crystals, PPL, X300, s.no. Z2.

Khurmala fig 16Fig. 16 Few beds of the Zawali Formation and other section contain fossils which are show in these photos: Green algae: 1-Clypeina (Z7-Z13), 2- Cymopolia sp. (Z7-Z13), 3- Hamulusella (Z7-Z13), 4- Cymopoliaellongata Defrance, oblique section (Z7-Z13).

5- Chalky limestone with dasycladals and forams (Z7 -Z13) 

6-Fragment of red algae (Z7 -Z13), 7- Corals (Z7-Z13)

8- Nummulite (Z7-Z13).

Miliolids: 9- Austrotrillinaeocaenica n. sp. (Z7 -Z13), 10- Biloculina (Z7 -Z13)

Soritids: 11, 12- Orbitolites (Z7-Z13),

Rotalids: 13- Lockhartia (Z7-Z13), 14- Sphaerogypsina (Z7-Z13).

The bar is 0.5 mm. All photos are taken under PPL setting of polarizer microscope

Khurmala fig 17Fig. 17 Tectonic and paleogeographic model during: a) Paleocene, b) Eocene which shows the position of deposition in a lagoon paleohigh (modified from Karim et al. 2008)

3.1. Correlation of five sections

     The stratigraphic column the four-studied section is drawn and correlated with each other. Moreover, the column of the type section of the Khurmala Formation, in the well-K114, is drawn according to the description of Bellen et al. (1959). This column is correlated too with the four other ones (Fig.18). The correlation shows extraordinary facies change between the columns, which is characteristics of the near shore (or shelf) of the foreland basin.

    From the description of the type section by Bellen et al.(1959),  it is clear that Gercus Formation is absent in the type section of the formation; this absence is not means that deposition is stopped or the area is uplifted but it means decrease of the clastic sediments influx and  increase of carbonate sedimentation during deposition of Gercus Formation. Due to this high content of carbonate, Bellen et al. (1958) had combined the Gercus Formation with Khurmala Formation. In the studied section, similar contend of carbonate is present in the Gercus Formation which represented by marl, marly limestone, and few beds of fossiliferous limestone in both Zawali and Dara Rash sections (Fig.10). Moreover, Khanaqa and Karim (2015) observed in the field that the latter formation is changes lateral toward southwest to Khurmala Formation on the southwestern limb of Sagrma (Qaradagh) anticline. The sedimentation in Mirade section is opposite to that of the type section as neither Khurmala nor Sinjar Formation is deposited in their stratigraphic position between Kolosh and Gercus Formation. Their position is occupied by 30 m of light grey to yellow succession of clastic sediments of sandstone marl and marly limestone with few beds of conglomerates (Fig.18-3).

Khurmala fig 18Fig. 18 Correlation of the four-studied section with the type section of the Khurmala Formation.

 

4. Conclusions

This study has the following conclusions:

1. A thick dolomitic limestone succession is found and studied stratigraphically and lithologically in the stratigraphic position of Sinjar Formation in Sulaimanyiah Governorate 

2. Many evidences are cited that proved that the dolomitic succession affinity belongs to Khurmala Formation

3. The new environment and lithological study suggest that the studied succession is more suitable to be called Khurmala Formation than Sinjar Formations.

4. The environment is indicated as back reef or lagoon.

5. The Zawali section is suitable to be assigned as surface type section (or supplementary section) of the Khurmala Formation

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