Iraqi Bulletin of Geology and Mining

Recognition, identification, and correlation of formal lithostratigraphic units should always follow the rules of the definition of lithostratigraphic units established in the Stratigraphic Code of Nomenclature, set by the International Stratigraphic Commission.
This case study is attempting at elaborating on this argument by discussing the identification and differentiation between the Sinjar and Khurmala formations in outcrop and well sections.
Stratigraphic data for this study were compiled basin-wide, with nearly fifty localities of both formations from the Zagros foreland basin of Kurdistan in NE Iraq. Examinations include a review of microfacies documentation, Facies reinterpretation as well as sequence analysis.
The Sinjar and Khurmala formations are carbonate units developed during the final filling stage of the Zagros foreland basin of northeast Iraq. The Sinjar Formation is characterized by shallow marine coralgal-foraminiferal limestone of reefal, lagoonal, shoal, and overall ramp setting. Other lithologies such as dolomitic limestone or marly limestone are minor and secondary. The Khurmala Formation, on the other hand, is dominated by thick beds of dolostone with secondary lithologies including recrystallized limestone and dolomitic limestone and marly limestone. Microfacies analysis of the Khurmala Formation reveals that it represents a lagoonal lithofacies equivalent to the lagoonal facies of the Sinjar Formation but intensively dolomitized at specific areas of the basin. This close relationship between the two formations, leading in some cases to mixing between both lithologies or rather confusion and misidentification. The best way of differentiating between the two units is by adhering to the lithostratigraphic rules and principles of the formal stratigraphic description, which emphasize the formal lithostratigraphic description of each formation.

In the current study, biostratigraphy and paleoecology of the Anah Formation have been investigated. The study area is located in the Sulaimanyah Governorate, Kurdistan Region, Northeast Iraq where the Darzila section has been sampled. Twenty-five species of larger foraminifera and skeletal fragments of coral, echinoid spine, pelecypods, and gastropods are described in seven samples collected from the Darzila section. Based on the distribution of the larger-benthic foraminifera and other skeletal grains, two assemblage biozones of the Late Oligocene – Early Miocene age have been recognized. According to the paleoecological parameters, such as temperature, nutrients, depth, and sa¬linity in the study area, the Anah Formation has deposited the euphotic zone, abundant imperforate foraminifera are present, sub-tropical waters under oligotrophic to mesotrophic middle ramp environment with normal to a higher salinity inner ramp setting and at water depths that ranged from 40 m to 80 m, and a temperature about 18 – 25 ºC.

The biostratigraphy and chronostratigraphy of Late Jurassic – Early Cretaceous (Tithonian – Aptian) successions at three outcrops in the Kurdistan Region, northern and northeastern Iraq (Amadia, Gara, and Barsarin sections) are studied depending on ammonite, planktic, and benthic foraminiferal contents. The studied formations: Chia Gara, Sarmord, and Qamchuqa, are recorded in all studied localities, while Garagu and Balambo formations are exposed at some studied localities. Age determination of the Chia Gara Formation relied on the ammonite fauna. The ammonites investigated are the major assemblage fauna of the Durangites Zone, which corresponds to the Late Tithonian. The detailed planktic foraminiferal investigation in Balambo Formation permits the recognition of five well-defined zones, these are Favusella hoterivica Interval Zone, Hedbergella sigali Interval Zone, Globigerinelloides ferreolensis Interval Zone, Globigerinelloides blowi Interval Zone, and Globigerinelloides algeriana Taxon Range Zone (part), which reveal a Late Valanginian to Late Aptian age.
The stratigraphic distribution of the benthic foraminifera shows three zones, these are Everticyclammina kelleri Assemblage Zone, Pseudocyclammina lituus Assemblage Zone, and Palorbitolina lenticularis Taxon Range Zone, the 1st and 2nd zones were recognized in the Sarmord Formation at Amadia section, which extends in age from late Valanginian to Hauterivian. While the 3rd zone is recorded from Qamchuqa Formation at the Gara section representing the Early Aptian age.

Five new ostracod species belonging to three genera from the Fat'ha Formation (Middle Miocene) in the Takia area, Darbandi Bazian anticline Sulaymaniyah, Northeastern Iraq. These species are Schneiderella takensis sp.nov., Schneiderella bazensis sp.nov., Sulcostocythere takensis sp.nov., Sulcostocythere bazeansis sp.nov., and Neomonoceratina takensis sp.nov. Those genera are showing affinities with ostracods of Mediterranean and Indopacific Bioprovinces.

Surface roughness (SR) is a significant geomorphic factor that has been effectively applied to determine material characteristics, present and past processes, and the period passed by since development in the environmental and earth sciences. Thus, this type of study is essential for analyzing SR and its importance. The research efforts to display a coherent evaluation of techniques and remote sensing data. The digital elevation models (DEMs) data were taken into account for quantifying the SR of landscape in different scales in selected areas that belong to the Kurdistan region, north of Iraq. The various types of DEMs {ALOS PALSAR (12.5 m) and SRTM in (30 m) and (90 m) resolution} as remotely sensed data integrated with GIS techniques were used to calculate SR regarding different neighborhood sizes {51 × 51 and 100 × 100 cells moving window size (MWZ)} in the both selected areas. The first study area is a mountainous terrain characterized by a number of anticlines and synclines that are located in High Folded Zones (HFZ), while the second study area is virtually a plain that is located in Low Folded Zones (LFZ). It found that SR calculation in wide and mountainous areas can be efficiently analyzed in more detail by using coarse-resolution DEMs from large MWZ, such as 100 × 100 cells, whereas high-resolution DEMs can be considered for studying SR in small, urban, and plain areas to reach detail information regarding smaller MWZ.
The results show that the E and W segments of Safeen and the western segment of Shakrok anticlines have the highest SR values, which indicate high incision at elevated and extremely eroded parts of area one, although Bani Bawi, Pirmam, and Khatibian anticlines have moderate to low SR values due poorly incised. On the other hand, the areas within LFZ are mainly flat and have the lowest values of SR, which indicate a very poorly dissected landscape except for the northwest part of the area two relatively has a higher SR value.

At the procedural level and according to climate factors, the study area has an arid climate. About 12.4% of the total rainfall was observed as excess water in the study area over 30 years. The amount of groundwater recharge, measured in millimeters per year at a rate of 16.7 mm/year, was 5.37% of the total rainfall. The main direction of the flow net in the studied area was from west to east, and the water table levels ranged from 321 to 409 m above sea level. The values of a saturated thickness (b) for the Rabia sub-basin were between (73 and 127 m).
Depending on the results of pumping test analysis from eight wells, the hydraulic conductivity values (K) of the Rabia sub-basin aquifer ranged between (2.91 to 5.55) m/day. The Transmissivity (T) values ranged from (235.3 to 704.2) m²/day, while the storage coefficient (Sc) values ranged between (1.16 x 10ˉ⁴to 3.98 x 10ˉ). This value indicates that the aquifer is confined.

Groundwater potential recharge (GWPR) zones are an important process in managing water resources. Six thematic layers were used to produce GWPR mapping for Wadi Al-Batin alluvial fan, Southwestern Iraq with GIS environment and analytical hierarchical process (AHP), including geology, lineaments density, slope gradient, drainage density, soil, and slope aspect. Based on the importance, the thematic layers are ranked, which control the GWPR. Drainage density, lineament density, slope aspect, and slope gradient maps are classified into five classes, whereas, geology and soil are classified into six classes. The classes are weighted based on the magnitude of groundwater recharge potential. The AHP technique divides the entire into three zones based on GWPR values: high, moderate, and low. The final GWPR map demonstrated that the western and northwestern parts of the alluvial fan have greater groundwater recharge potentials with 70% of the total area due to the increase in the infiltration rates as a result of the gravely and sandy soils besides the agricultural land use in the present areas. However, the other part of the fan ranged between moderate and low with 25% and 5% of the total area, indicating suitable zones for groundwater artificial recharge processes.

The study area is located in the northern Iraqi province of Erbil, covering a total area of about 1400 Km2 (3.5% of Iraq). The Erbil basin is mostly covered by Quaternary sediments, with only a few outcrops of Miocene – Pliocene formations in the east and northeast of Sharabot-Dedawan highlands, Avanah Mountain in the west and southwest in narrow strips, and Damirdagh in the north. The lithology of sediments ranges from clay, silt, sand, and gravel (sandstone, clay stone, and conglomerate). Erbil Basin, also known as Dashty Hawler Basin, Erbil provinces is the largest groundwater reservoir, with a surface area of 3200 Km2 and a depth of approximately 800 meters. Erbil Basin, one of the Middle East's most important groundwater basins, is bounded on the north by the Greater Zab River and on the south by the Lesser Zab River. Thirty water samples (27 samples of groundwater wells, and 3 samples of wastewater channels) were collected during May (Water surplus period) and September (Water deficit period) 2020 in Erbil central sub-basin and analyzed. Physical analyses include temperature (T), pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Biological Oxygen Demand (BOD5), Chemical oxygen demand (COD), Dissolved oxygen (DO), Total Suspension sediments (TSS), whereas the geochemical analysis included concentration determination of the major, minor and trace elements. This article aims to evaluate the pollution in groundwater of the Erbil central sub-basin due to different kinds of wastewater, the samples of water in the study area were collected from different locations and sources, deep wells, and waste. all chemical, physical, and trace elements parameters are presented in this work, the pollution has been founded in the study area due to waste water by Kahrez (old groundwater distribution in Erbil basin), cesspools, and septic tanks.

The current study aims to assess the groundwater quality in the Wana area, Northwest of Mosul. Water samples were collected from 18 selected wells within the study area during the dry season of October 2020 and the wet season of April 2021. Field and laboratory measurements including electrical conductivity (EC), TDS, pH, Total hardness, and major and some minor ions analyses were performed following standard methods. The results revealed a wide variation of EC values ranging from 0.66 to 5.09 ds⋅m-1. All wells have hard water due to the presence of gypsum and carbonate rocks. The water quality index (WQI) values showed that wells drilled in the Fatha Formation and wells of mixed water from both the Fatha Formation and the Quaternary sediments provide low-quality drinking water. Wells that only penetrate the Quaternary sediments yield good-quality drinking water. According to the irrigation WQI, the Fatha Formation wells produce low-quality irrigation water, and the water quality of wells drilled in Quaternary sediments or that penetrate both the Fatha Formation and Quaternary sediments (mixed water) ranges from excellent to acceptable for irrigation purposes.

The Unit Hydrograph (UH) and Soil Conservation Service Curve Number (SCS-CN) are prevalent methods for estimating peak flow and peak time within the hydrological river basins. Different types of data, such as gauging data, morphometric analysis, and Land Use-Land Cover (LULC), are used to derive UH for the Kanarwe River Basin (KRB), which is an off-the-Lesser Zab River Basin (LZRB). Different hydrograph models, including HEC-1 (Hydrological Engineering Centre), TR55 (Technical release 55), HEC-HMS (Hydrological Engineering Centre-Hydrological Modeling System), Rational method, and Snyder unit hydrograph, have been applied and correlated with field data. Metrological data, geological setting, and land cover were integrated into the Geographic Information Systems (GIS) and Watershed Modelling System (WMS 11.1). The peak time (Tp) and peak flow (Qp) were estimated based on the five applied models. The results for models are (Qp = 739.93 m3/sec, Tp = 20 hr), (Qp 181.4 m3/sec, Tp = 14 hr), (Qp = 800 m3/sec, Tp = 12 hr, (Qp = 341.13 m3/sec, Tp = 11.65 hr), (Qp = 443 m3/sec, Tp = 19.9 hr), (Qp = 243 m3/sec) for HEC-1, TR55, HEC-HMS, Rational method, Synder unit hydrograph, and observed data respectively. The observed model (field data) peak time and peak flow value best agreed with the peak time and peak flow value of TR55, Snyder, and Rational models. Our finding confirmed that the geomorphoclimatic unit hydrograph, such as (Snyder) is highly efficient and more realistic for estimating peak time and peak flow for large basins than other models because it relates to basin characteristics.