IRAQI BULLETIN OF GEOLOGY AND MINING
مجلة الجيولوجيا والتعدين العراقية
ISSN 1811 - 453
اهداف ومجال النشر تعليمات النشر للمؤلفات البحوث المنشورة هيئة التحرير
BIOSTRATIGRAPHY OF BEKHME FORMATION (UPPER CRETACEOUS) IN SELECTED SECTIONS, KURDISTAN REGION, NORTHEAST IRAQ
Salam I. Al-Dulaimi and Roa'a A. Al-Obaidy
Received: 24/ 07/ 2016, Accepted: 15/ 12/ 2016
Key words: Bekhme, Biostratigraphy, Biozones, Khanzad, Iraq
(p. 1 – 14)
ABSTRACT
The Bekhme Formation belongs to the Late Campanian – Early Maastrichtian cycle. The formation consists mainly of thick and massive bedded limestone and dolomitic limestone. The main objective of this study is to determine the microfossil and the age of Bekhme Formation.
Forty four species of benthonic and planktonic foraminifera have been recognized including one species described for the first time in Iraq.
Depending on the assemblage of different groups of foraminifera, two biozones of benthonic foraminifera were determined, namely:
- Murciella cuvillieri Range Zone.
- Omphalocyclus macropours-Orbitoides apiculatus-Siderolites calcitrapoides Assemblage Zone.
According to the identified biozones the age of Bekhme Formation is estimated as Late Campanian – Maastrichtian at Shaqlawa, Bekhme and Khanzad sections.
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AN INTERFINGERING OF THE UPPER CRETACEOUS ROCKS FROM CHWARTA – MAWAT REGION, NE IRAQ
Fadhil A. Lawa, Amanj I. Al-Karadakhi and Khalid M. Ismail
Received: 03/ 08/ 2016, Accepted: 02/ 03/ 2017
Key words: Maastrichtian, Aqra, Tanjero, Interfingering, Reef-Flysch, Iraq
(p. 15 – 26)
ABSTRACT
The Upper Cretaceous interfingering sequence of Chawrta – Mawat region have been described, and analyzed for their stratigraphy, and paleontology. These results are interrelated with respect to the characteristics of the depositional environment, the faunal variation and paleogeographic setting. The interfingering sequence is represented by the Tanjero Formation and Aqra Formation. This study points out a general variation trend both laterally and vertically from deep-flysch facies to reefal facies, that is from the margin of the carbonate platform to the central part of mobile trough through a transitional zone' between them. Several genera and species of macro and micro fauna are identified, from complete forms and thin sections. The giant Pelecypods (especially Rudist), gastropods with the echinoids, cephalopods, corals, brachiopods are the most common macrofossils, while the dominated large foraminifera are: Loftusia, Omphalocyclus, and Orbitoides. Micro and macro fauna testifies to the Middle and late Maastrichtian age. The Loftusia minor – Loftuisa morgani Zone, used as indictor for the Middle Maastrichtian age, while Loftusia elongate – Lofusia persica Zone, and mostly point to Late Maastrichtian. The Aqra/ Tanjero interfingering interval represents a ridge about 18 Km, in length and extends mostly NW – SE, forming a lentil body of variable thickness 0 – 225 m, within Kurdistan foreland basin. The variation from the flysch clastics is quite gradational laterally and vertically into Aqra reefal facies and most probably formed due to the presence of submerged highs within the rapidly subsiding trough basin, at the end of the Maastrichtian and termination of the paroxysmal phases of the Laramide orogeny.
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DOHUK SYNCLINE AS AN ARTIFICIAL RECHARGE AQUIFER, NORTHERN IRAQ
Nabeel K. Al-Azzawi, Myasar S. Al-Saraj and Jalal H. Younis
Received: 09/ 02/ 2017, Accepted: 11/ 05/ 2017
Key words: Artificial recharge, fold surface interpolation and Dohuk Syncline, Iraq
(p. 27 – 42)
ABSTRACT
Artificial recharging was carried on Dohuk Syncline. The syncline is located between Baikher Anticline to the north and Dohuk Anticline to the south. Dohuk city occupies the surface area of this structure. The syncline extended about 17.1 Km in a generally east-west direction. It is a narrow syncline due to its location between two steep limbs of Baikher and Dohuk anticlines. Moreover, the syncline is very narrow near Itut village which represents the eastern plunge of the syncline and becomes wider towards the west near Aloka village. Alluvial deposits, vegetation and urbanization cover the surface of this syncline where the Fatha and ridges of Pila Spi formations surround it.
The distinct property of the Pila Spi Formation of being well-jointed limestone makes it an excellent and adopted aquifer for water storage. Moreover, it underlys Fatha Formation and overlys Gercus Formation, which are considered as aquitard and aquiclude confining beds respectively.
The geometry and the shape of this syncline were determined by mathematical (Lagrangian Interpolation) method. It was used to obtain the subsurface or the hidden parts of the syncline depending on the bore-holes data and the available seismic sections. This method was applied on three transverse sections. Finally, SURFER program was utilized to display the final geometrical shape of Dohuk Syncline in three dimensions.
The project is an attempt to determine the capability of this syncline for artificial recharge of water and to be used as an aquifer for the city domestic uses. The size of this aquifer is estimated as 7.38 Km3 and the pore size is 1476452509.2 m3 depending on the limestone porosity of 20%. In addition, the infiltration of rainfall is determined as 2521116 m3/year. Consequently, the aquifer needs very long time to be fully recharged. Subsequently, natural recharging is not enough and necessitates a proposal for recharging the aquifer artificially. Moreover, some ideas were proposed to achieve this purpose.
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ACTIVE TECTONIC ASSESSMENT OF MANDILI WATERSHED USING GIS TECHNIQUE
Luay D. Yousif
Received: 01/ 03/ 2017, Accepted: 20/ 07/ 2017
Key words: Dem, GIS, Hypsometric Integral, Mandili, Stream, Drainage basin, water
(p.43 – 62)
ABSTRACT
Geomorphic indices such as Asymmetry Factor (Af), Stream Length Gradient ratio (Sl), Hypsometric integral (Hi), Valley floor width to height ratio (Vf), Basin shape factor (Bs) and Mountain front sinuosity (Smf), are particularly useful in tectonic studies, because they can be used for rapid tectonic evaluation of large areas, and the necessary data often can be obtained easily from topographic maps and aerial photographs.
Geographic Information system (ArcGIS V-9.3) and Digital Elevation Model (DEM) with resolution of 30 m have been used to extract the stream network watersheds of Mandili Quadrangle, sheet No. NI-38-11, scale of 1: 250 000, east of Iraq.
Mandili Quadrangle is chosen to analyze the relationships between the morphometric characteristics and the active tectonics. The area concerned is located at the western edge of the well-known Zagros mountainous belt, which is a well-known tectonically active area.
Ten sub-basins were extracted by DEM and the above mentioned morphometric indices. In addition relative active tectonics were calculated to evaluate the tectonic history of the area.
The results show that the active tectonic effects on Mandili area range between inactive (low) to moderately active, which may be due to the soft and weakly resistant sediments that cover almost all the area concerned or due to prevailing climatic conditions in a tectonic quiescence.
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THRUST FAULT IN THE MAASTRICHTIAN SEQUENCES OF MAWAT AREA, NE IRAQ
Kamal H. Karim, Sirwan H. Ahmad and Hawar F. Esmael
Received: 24/ 10/ 2016, Accepted: 11/ 05/ 2017
Key words: Thrust fault, Tanjero Formation, Aqra Formation, lateral thrust, Mawat area, Iraq
(p. 63 – 77)
ABSTRACT
Stratigraphic studies of Maastrichtian Tanjero and Aqra formations and compression of microtectonic faults in Khewata – Dolbeshk valley constrains new geological setting of the Mawat area northeast Iraq. During Middle – Late Maastrichtian a carbonate-siliciclastic succession deposited in front of the subducted ophiolite and accretionary prism. These successions are well developed in the area. This study concentrates on the overthrust sequence and identifies the geometry of the thrust fault. The reefal limestone/ shallow clays succession are thrusted over reefal limestone/ marl-sandstone succession. This thrust fault illustrates (1) these two successions were initially deposited laterally beside each other during the Maastrichtian and (2) the limestone/ clay sequences belong to the Tanjero/ Aqra formations and not to the Red bed Suwais. The fault initiated during the last stages of collision, formed duplexes-imbricated thrusting fault and it brought the shallow facies over the deeper one. The thrusting can also be identified on Google Earth image manifested by vertical repetition of Aqra Formation and it changes to reverse fault when it laterally meet the thicker and massive limestone of Aqra Formation. The displacement of the thrust fault is accommodated by a fault-propagation folds in its southeastern tip. In addition to the studied thrust fault, the valley contains many well developed relatively smaller compression faults which might form in a relation to the main thrust fault.
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MINERALOGICAL AND INDUSTRIAL ASSESSMENT OF CLAY FROM PARTS OF THE FOLDED ZONE IN KURDISTAN REGION FOR CERAMIC PRODUCTION
Tola A. Mirza and Rezan Q. Faraj
Received: 20/ 11/ 2016, Accepted: 11/ 05/ 2017
Key words: Briquettes, Ceramic, Clays, Mineralogy, Iraq
(p. 79 – 97)
ABSTRACT
Clays are used in the ceramic industries largely because of their contribution to the molding and drying properties of the wares being produced; many clays, such as kaolinite and red clays, are used because of favorable behavior during firing or because they produce favorable properties in fired ware. To assure the most effective use of a clay, the ceramic technologist must meet the problems of purification, the improvement of the working properties of clays through additions of non-plastic materials or chemicals and their behavior during firing. Therefore this study addresses the problems of some clay deposits from parts of the folded zone in Kurdistan Region for ceramic industry. X-ray diffraction is used to establish the mineralogical composition. It is found that the main clay minerals of these samples are chlorite, smectite, mixed layer, illite, and kaolinite, in addition to the non-clay minerals such as quartz, calcite, dolomite and feldspar. The raw materials were ground and sieved; some of the raw materials were mixed in different proportions in order to prepare different mixtures. Three different mixtures were prepared using red clay sample, kaolin, granite, sandstone, and limestone. Briquettes were molded from clay alone (A) and from different mixtures (1B, 2C) using a semi-dry pressing method (10% moisture content and pressure 5.6 in/cm²) in a dimension 5 × 5 × 1 cm. The briquettes were fired at three different temperatures (1125, 1150 and 1175 °C) with at rate of heating of 30 C°/h. The evaluation tests, physical and mechanical properties as well as chemical compositions of the studied samples show that the fired briquettes made from those samples which contain considerable amount of Al2O3 and low content of CaO such as samples 1, 5 and 7 from Fatha Formation; 8 and 9 from Injana Formation give the best results for the production of floor tile, wall tile, facing tile, and clay brick industry. The results also, showed that the best mixture to adequate characteristics for ceramics industry are mixture 2C fired at 1175 °C.
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ASSESSMENT OF THE RUTBA FORMATION SILICA SAND AS ABRASIVE FOR GRINDING AND POLISHING GALENA: A CONTRIBUTION IN ORE MICROSCOPY
Salih M. Awadh and Rana A. Ali
Received: 01/ 03/ 2017, Accepted: 20/ 07/ 2017
Key words: Silica sand; Abrasives; Polishing; Galena; Reflectance; Roughness
(p. 99 – 106)
ABSTRACT
This study aims to assess the Iraqi silica sand collected from Rutba Formation as an abrasive for grinding and polishing galena surface for mineralogical study under the reflected light microscope. Grinding is performed using four-grain sizes of silica sand (68, 46, 30, and 18 µm) which are equivalent to 260, 325, 600, and 1200 mesh respectively. Polishing and buffing stages are done using two-grain size of diamond paste (7 and 2.5 µm). The reflectance (R%) values are inversely proportional to the grain size (the lower particle size, the higher the reflectivity), while the surface roughness (Ra) is directly proportional to the grain size. The reflectance is increased from 0, 5.4, 12.2, 16.4, 23.5, 28.3, to 32.3% and roughness is decreased from 57.2, 47.8, 35, 22.5, 8.4, 6.9, to 3.3 µm with grinding and polishing abrasives of grain sizes of 68, 46, 30, 18, 7, and 2.5 µm. The ideal reflectance of the polished surface of galena at 546 nm (air) is 43.1%, and 41.9% at 589 nm in air. The highest reflectance of 32.3% at 546 nm in air achieved by this study is adequate to diagnose galena and its texture intergrowth under the polarized reflected light microscope.
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PETROGRAPHICAL AND MICROFACIES STUDY OF JERIBE FORMATION (M. MIOCENE) IN ASHDAGH MOUNTAIN, KURDISTAN REGION, IRAQ
Rzger A. Abdula, Mohammad S. Nourmohammadi, Gailan R. Rashed and Nabard Q. Saleh
Received: 01/ 03/ 2017, Accepted: 20/ 07/ 2017
Key words: Jeribe Formation; Ashdagh Anticline; Miocene; microfacies; diagenetic processes
(p. 107 – 118)
ABSTRACT
This study deals with the Middle Miocene Jeribe Formation in the Ashdagh Anticline in Darzila Village near Sangaw in Sulaimani Governorate, Iraq. Stratigraphic analysis has shown that Jeribe Formation consists of recrystallized and dolomitized, mostly limestone which, as a whole, supported its reservoir potential. Petrography has provided a diversity of fauna such as large benthic foraminifera, Astrotrillina sp., Miliolid in addition to Borelis melo curdica, which for a long time has been considered an index fossil for this formation. Other fauna includs several types of mollusks. The Jeribe carbonates were subjected to various diagenetic processes ranging from micritization, dolomitization, cementation, compaction, dissolution, and others. The formation consists of three major limestone microfacies: mudstone, wackestone, and packstone/ grainstone. The evidence from petrography and facies analysis support that the Jeribe Formation was deposited in restricted marine environment.
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SCIENTIFIC NOTE:
A DISCOVERY OF MAMMOTH TUSK FOSSIL IN THE "BAI HASSAN FORMATION" NORTHEAST, IRAQ
Luay D. Yousif
Received: 26/ 03/ 2017, Accepted: 20/ 07/ 2017
Key words: Bai Hassan Formation, Cham Chamal, Conglomerate, Mammoth, Tusk, Iraq
(p. 119 – 122)
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