Iraqi Bulletin of Geology and Mining

The Cretaceous/ Paleogene boundary in the Kurdistan region of Iraq is still under debate. Most studies consider the Danian sediments to be mostly missing. We examined the boundary succession of the Chinarok section in the Sulaimaniyah area of the Kurdistan Region to examine calcareous nannofossil assemblages as well as the biostratigraphy of the boundary. The rock strata in the study section are characterized by alternations of organic shale, marlstone, siltstone, fine- grained sandstone, and organic limestone interlayer within the Tanjero Formation (upper Maastrichtian) and the overlying Kolosh Formation (Paleocene – Lower Eocene). The study shows that deposition across the boundary is continuous with no break in sedimentation. The boundary is biostratigraphically delineated by the first occurrences of Biantholithus sparsus, Cruciplacolithus spp. and Coccolithus pelagicus plus an acme of Thoracosphaera operculata of biozone NP1 that indicate no hiatus; there is reworking of the Cretaceous taxa all above the Cretaceous/ Paleogene boundary into zones NP1 and NP2.

The Eocene phosphatic Ratga Formation of the Iraqi Western Desert consists of three members from bottom: Swab, Damlouk and Mugur Members. This study is focused on the Damlouk Member which is represented by 40 – 50 meters thick sequence of alternating shelf carbonates of mollusk-nummulites association, cherty phosphatic limestone horizons and basinal chalky limestone and marlstone. This member is an important part of a thick cyclic phosphorites-bearing sequence extends from the Upper Cretaceous to the Eocene. It is the aim of this paper to shade some lights on the basic characters, origin, and stratigraphic associations, through facies modeling and sequence stratigraphic analysis. This is done by examining the Damlouk Member sequence in three localities chosen from Wadi Al-Ratga and Wadi Akash around Akashat area at the Western Desert of Iraq. The Damlouk Member is deposited over a gently sloping ramp system. Sedimentary facies in seaward direction includes: coastal plain (not well represented in the study area), Nummulite shoals limestone, and the Oyster bank limestone, of the inner ramp. The middle ramp is represented by gray bioturbated and granular limestone-phosphate horizon. This facies is occasionally, punctuated by storm-derived shelly-nummulitic limestone lenses. The intercalation of the phosphatic facies with the basinal marlstone and chalk often occur in the seaward part forming the outer ramp facies. The latter facies opened up into the basinal marlstone and chalk of the Jaddala Formation or its equivalent. Both the middle and outer ramp facies are characteristically silicified and contain dark chert nodules and horizons. The Damlouk Member consists of two sedimentary sequences deposited during the Late Ypresian to Middle Lutetian (Middle Eocene), and developed by two fourth-order eustatic cycles. This is inferred from facies sequence as well as correlation with the regional and global eustatic curves of the sea level fluctuations. Both cycles have similar facies type, distribution and stratigraphic evolution. Each of the two sequences consists of well developed TST and HST which are separated by fingers of basinal marlstone from the adjacent Jaddala representing the MFS. Each of the two sequences is bounded by Type-2 sequence boundary which is characterized by sharp facies changes.

The depositional environment of Chia Gara Formation (Upper Jurassic – Lower Cretaceous) in Northern Iraq is studied. The formation is exposed in the High Folded Zone, and Imbricated Zone of Iraq. The selected sections for this study are Banik (outcrop), Barsarin, (outcrop) and well Aj-12; located in the High Folded, Imbricated, and Foothill Zones respectively. The Chia Gara Formation is lithologically composed of black shale, thinly bedded brown argillaceous limestone, thin to medium limestone, and marly limestone in uppermost part. Skeletal grains consist of macro and micro pelagic fauna. Pelagic fossils include Ammonites, radiolarian (Spumellarian Group), ostracods, planktonic forams (Globigerina), pelecypods, and others. Non-skeletal grains are not observed in the current study. The groundmass of the Chia Gara Formation is dominated by micrite which is often replaced by coarser microspar. Limestones of Chia Gara Formation are divided into three principal microfacies: Mudstone, Wackestone, and Packstone. Each of these is further subdivided into submicrofacies. Using lithology, paleontology, and microfacies criteria, the most likely depositional environment of the Chia Gara Formation is concluded as toe of slope to deep open marine environment.

Faults of Neogene age in the Zurbatia area have been analysed in the light of Anderson faulting theory, Jaeger reactivated assumption and plate tectonic theory to derive the mechanism style and paleostress systems prevailing in the study area. According to the graphical methods (improved right dihedral and rotational optimization methods), the NE – SW compressive force of the Oligocene changed later in Late Miocene age into E – W compression. This study suggests, that the area is affected by gradual change in stress regime from NE – SW very high compressional phase of faulting to very low compressional phase. The NE – SW and E – W directed pressure is presumably identical with the northeasterly driving motion of the Arabian Plate.

Morphometric parameters of the Al-Teeb River Basin (TRB), located in the southeastern part of Iraq, are studied to evaluate the hydrological condition, developing of watershed management and the environmental effect. These parameters are calculated using GIS software and standard mathematical formulae as well as satellite image of the Digital Elevation Model (DEM). According to morphometric analysis results (TRB) has a total area of 1990 km2 and is designated as 5th order basin, with maximum length about 112 km and average width about 17.83 km. The basin is strongly elongated with an elongation ratio of 0.45 and circularity ratio 0.15. The relief ratio of (17.30) m ⁄ km reflects the potential activity of water erosion in the basin and the basin is under intense relief and steep slope. The low value of drainage density in the Al-Teeb Basin of (0.47) km/km2 can be attributed to highly resistant rocks, high topography, high to moderate lineaments, and high infiltration capacity which lead to coarse drainage texture. The hypsometric curve and hypsometric integral of (TRB) reveal that the basin is fully stabilized and approached the old stage.

Wadi Al-Ajeej” drainage basin is one of the areas in the Al-Jazirah Province, experiencing shortage in water-resource in Iraq. Morphometric analyses are made in this study for “Wadi Al-Ajeej” drainage basin to support formulating plans, on the basis of the results, and to help in a better implementation. GIS techniques have been adopted to identify morphologic features and analyse their properties. Morphometric parameters such as linear, aerial and relief aspects of the drainage basin were computed and determined. The entire drainage basin of Wadi Al-Ajeej covers 3804.7 Km² with seventh order stream network, comprising three contiguous sub-basins; Al-Badee, Al-Khazrajia and Al-Hamal sub-basins which occupy 80% of the area in the northern and eastern parts of the basin. The drainage network of the three sub-basins in addition the entire Al-Ajeej basin are delineated using the Digital Elevation Model (DEM) 30 m resolution. The drainage network shows that the terrain exhibits dendritic, sub-parallel and trellis drainage patterns. Estimated drainage density is approximately 1.3 Km/Km² and has coarse drainage texture. The bifurcation ratio in all subbasins has experienced moderate structural disturbances, by “Tel-Hajar” subsurface extensional structure, that change the main streams flow from NNW – SSE to NNE – SSW. Al-Badee, Al-Khazrajia and Al-Ajeej subbasins are the highest relief ratios (17.2, 15.6, and 12.7 respectively), due to their high reliefs (1126 m, 966 m, and 1162 m respectively), while Al-Hamal subbasin has low relief ratio (2.14) due to its low relief (128 m). Drainage density results refer to excellent drainage basin (with moderate rates of infiltration and surface runoff) and coarse texture (indicate low erosion and high relief). The elongation ratio shows that three subbasins (Al-Badee, Al-Khazrajia and Al-Hamal) possesses an elongated shape pattern, but only Al-Ajeej subbasin seems to be close to a circular shape.

The growing water shortage resulting from the recent drought season spanning from the last decades in Sulaymaniyah City has led to resurfacing the question of water supply. To cover for the long, hot and dry seasons and to make use of the limited precipitation in the higher elevation areas of the city, tenths of man-made subterranean aqueducts known as Karez or Qanat have been developed throughout the history of the city. This paper provides an insight into the current status of Sulaymaniyah Karezes and their deteriorating conditions regarding structure and water quality due to unsustainable urbanization and improper licensing for land use in the city. Geological aspects with particular emphasis on hydrogeological conditions that made their construction and their long-term use possible have been examined. Terminology, function, and distribution of all infiltration Karezes have been recorded and previously drawn sketches reviewed. Water samples from Karez outlets are analysed for major, minor and trace elements and the results showed that some of them are polluted and not suitable for human consumption. It also advocates that some of them in the Sulaymaniyah City shouldn’t only be protected as a great city heritage but also be refurbished and reconsidered as sustainable and eco-friendly water supply system for at least irrigation and industrial use if not drinking.

The study area is located SE of Darbandikhan town, which is about 158 km far from the Sulaymaniyah city. In the present study, Analytic Hierarchy Process (AHP) based model and multiple parameter analysis are applied to identify forest fire risk zones in Sartak watershed using Geographic Information System (GIS) and Remote Sensing (RS) techniques. Satellite images are used to generate vegetation, roads, settlements and farmland maps. Slope gradient, slope aspect and elevation maps are derived from Digital Elevation Model (DEM). Whereas, the Tropical Rainfall Measuring Mission (TRMM) data is used to build up mean annual rainfall map of the study area. Forest fire risk zone map was delineated from the scored and weighted layers of all influencing factors on forest fire (vegetation, slope gradient, slope aspect, altitude, rainfall, distances from settlements, roads, international border and farmlands). As a consequence, the study area is classified into five forest fire risk classes. 16.16% of the total area falls in the category of very high risk, followed by 25.37%, 24.51%, 19.01%, and 14.95% in the categories high, moderate, low and very low, respectively. The results help and enable the institutions concerned with forests to set up appropriate fire-fighting infrastructure for the areas more prone to fire damage and exploit the geological and geomorphical situation of the study area to build a natural protection area.

Remote sensing and Geographical Information System (GIS) are used in this study to detect environmental changes in the vicinity of Al-Ahdeb oil field, southwest of Kut City, Wasit Governorate. Different image indices, such as Normalized Differences Vegetation Index (NDVI), Normalized Differences Soil Index (NDSoI), and Normalized Differences Salinity Index (NDSI) are used. Two LANDSAT images with acquired data of September 2007 and 2016 are used to detect the environmental changes and to detect the effect of Al-Ahdeb oil field before and after construction and industrial operation. The results of change detection show there is a high decrease in the vegetation cover during the year 2016 compared with 2007, where the area of vegetation cover has decreased from (165.85 Km2) in 2007 to (119.62 Km2) in 2016. The change detection results from NDSI show that the saline soil in (2016) is higher than those in (2007). The NDSI derived from Landsat TM (2007) image confirms that there is significant increase of salinity in the study area, where the calculated area of the salinity in 2007 is (5.65 Km2) while in 2016 it is (21.951 Km2). Change detection, using NDSoI, show that the land in the study area is going toward desertification and soil degradation. The decrease in the vegetation cover, which in turn led to soil erosion in addition to water shortage and the pollution by the waste of the oil field, could be the main reasons of the desertification in the area.

An electrical survey is carried out at Al-Rehaemia area within Bahr Al-Najaf Depression by applying Vertical Electrical Sounding (VES) and 2D Electrical Resistivity Tomography (ERT) techniques to determine the thickness and extension of the main aquifer used for irrigation purposes. A total of ten VESs are measured using liner Schlumberger array configuration with maximum AB/2 = 400 m along two traverses of 4km length, each traverse has five VES points of 1km spacing interval. The ERT survey is conducted along three parallel traverses, 400 m long each, using Wenner-Schlumberger array. The electrode separation for the data measurements is 10 m, whereas the distance between the traverses is 15 m. The VESs data are processed and interpreted using IPI2win software, whereas RES2DINV software is used for the 2D resistivity data. The penetration depth of the VES is about 350m, and it is closed to 70m for the 2D electrical resistivity sections. The results show the presence of four geoelectrical zones and the resistivity range is 2 – 80 ohm.m. The first zone is 1 – 4.5 m thick, characterized by relatively low resistivity and represents top soil. The second zone is 9 – 152 m. thick impermeable layer of marl and recrystallized marly limestone of the upper member of the Dammam Formation, and it is characterized by moderate values of resistivity. The third zone is 125 – 250 m thick carbonate rocks of the lower member of the Dammam Formation and represents the main aquifer in the area. The fourth zone is detected by VES only as an impermeable layer (Aquiclude) which consists of marl and evaporates and represents the Rus Formation. The results show that the depth of the groundwater level is about 23 m. They also showed a good agreement with the 2D electrical resistivity technique in determining the subsurface lithology of the area and the level of groundwater in the main aquifer as indicated by the geological data available.