Iraqi Bulletin of Geology and Mining

The current study of Jeribe Formation (Middle Miocene) at Zurbatiya area, South-East of Iraq. It is, structurally, located in the Low Folded Zone. The topic depends mainly on the study of microfacies under a microscope. One surface section in the Zurbatiya area is represented in the Wadi Al-Numur section. It is composed basically of dolomitic limestone. Petrography provides a diversity of fauna, such as benthic foraminifera Miliolid, Borelis melo curdica, and Rotalia in addition to Ostracoda, Algae, Coral, and Mollusks. Borelis melo curdica is considered an index fossil for the Jeribe Formation. The non-skeletal grains like peloids, ooids intraclasts, and extraclasts. The Jeribe Formation was affected by many diagenetic processes like neomorphisim, dissolution, cementation, dolomitization, compaction, and silicification. Sedimentary microfacies are classified into three main microfacies, which are dolomudstone, dolowackestone, and dolopackstone. These microfacies were divided into many submicrofacies, which are peloidal dolomudstone, ostracods dolomudstone, rotaliids dolowackstone, miliolid dolowackstone, bioclasts dolowackstone, green and red algae dolowackstone, red algae dolopackestone, and coral dolopackestone. The evidence from petrography and microfacies analysis supports that the Jeribe Formation was deposited in the back reef, reef, and lagoon environments.

Aqra Formation is a shallow marine deposit of the late – Cretaceous sedimentary cycle. According to the field lithological description, the two studied sections of the Aqra Formation are subdivided into three units. Based on sedimentological characteristics and fossils assemblage eleven facies have been recognized in both studied sections, their alternated association points to a wide range of depositional environments extended from tidal flat, back reef, reef, to fore- reef. Based on the fossil's appearance, the studied sections comprised two fossils biozone {Orbitoides media zone (part) and Liftusia morgani zone}, it is age determined to be late Campanian – Early Maastrictian in both studied sections. Sequence stratigraphic analysis, as calibrated by sedimentary facies and biostratigraphy delineated one sequence (Aqra sequence 1) of 2nd order, and their MFI correlation result with MFS studies in the Arabian platform indicated to maximum flooding stage dominated on the Arabian plate at the Latest Campanian.

Upper Albian and Lower Cenomanian biostratigraphy and microfacies types of the Mauddud Formation from Musaiyib well No.1, Central Iraq are described and examined, which consists of thick to medium bedded limestone, marly limestone rich in argillaceous material, green shale, and dolomitic limestone beds. Thirty-six species from twenty-two genera of benthic foraminifera in addition to calcareous algae, coral, bivalves, gastropods, rudist fragments, brachiopods, bryozoan, and echinoid fragments are recognized from the Mauddud Formation of the studied well. On the basis of the recognized benthic foraminifera three biozones were determined:
Mesorbitolina texana - Orbitolina qatarica Concurrent Range zone- Orbitolina sefini-Total R. Zone and Orbtolina concava Total R. Zone. Both suggest the Late Albian – Early Cenomanian age. The results of this study are compared with the work of others inside and outside Iraq. Based on the petrographical analyses, four major microfacies (Mudstone, wackestone, wackestone to packstone, and packstone), and nine sub-microfacies were identified. The Mauddud Formation was formed in a marine environment that was composed of the following three sub-environments: the inner ramp and the middle to the outer ramp.

The current study included the Bai Hassan Formation (Upper Bakhtiari) in the Zakho area of northern Iraq. Depending on the grain size class, structures, degree of rounding, sorting, and some other detailed field observations. This formation was divided into eleven lithofacies which are matrix-supported conglomerate, clast-supported conglomerate, laminated sandstone, sandy gravel, planar cross-bedded conglomerate, interbedded siltstone-mudstone, gravely sandstone, interbedded sandstone-conglomerate, lime matrix-supported conglomerate, and caliche lithofacies. These lithofacies are distributed into six coarsening-upward cycles consisting of complete and incomplete cycles, and these lithofacies include sedimentary structures such as imbrication pebbles, bedding plain, load cast, and gravely cross-bedding. The environment of the Bai Hassan Formation represents conjunctive alluvial fan with possible internal lake environments. The study includes the determination of source areas such as sedimentary, igneous, and metamorphic rocks.

The Shuaiba Formation (Aptian age) is an important formation due to its wide extent in Iraq and Arabian Gulf. In northern Iraq, it is called Qamchuqa Formation and has an important role in contracting the Arabian plate. The study focused on several wells, which are: ZB-290, WQ1-353, RU-358, R-624, and R-5 from several selected fields, such as Zubair, Rumaila, and West Qurna in southern Iraq. The purpose of the study is to determine the sedimentary and paleontological components of the Shuaiba Formation. The lithology of the Shuaiba Formation consists of very fine crystalline massive limestone that gradually converts to chalky limestone with a large percentage of dolomites, especially in the middle part of the formation. The thickness of the studied formation is about 50 – 110 meters and its main microfacies are two types, which are carbonate and dolomite. The carbonate is subdivided into five secondary types, which are burrowed bioclastic lime mudstone, planktonic foraminiferal lime mudstone, larger foraminifera wackestone, algal wackestone and mixed planktonic, and benthonic Foraminifera wackestone, in addition, to dolostone microfacies. The effect of the diagenesis in the formation is distinguished and most of these processes are destructive, such as dissolution and stylolite. The first depositional stage of the investigated area began with sea level rise following the deposition of the Zubair Formation from still stand. Shuaiba Formation deposited within the ramp setting as the water level rose. During the late Aptian, tectonic and sea levels were the active factors that controlled the deposition of the formation. According to data collected from microfacies and diagenesis processes, the Shuaiba Formation has several depositional environments, which are from the shallowest: restricted, open marine (inner ramp), mid ramp, and finally outer ramp. Generally, toward the upper sequence, the formation reflects deep deposits and then starts to be less deep until it is a shallow basin (Nahr Umr).

Electrical Resistivity and Induced Polarization Imaging (ERI and IPI) techniques are selected as non-destructive procedures, which provide continuous imaging of the subsurface. Recently, the demand has increased for obtaining raw materials that represent a more suitable and economical quantity of clay mass for brick industries. This is because of the unexpected expansion of cities and rising demand for brick materials due to their excellent characteristics of resisting earthquakes and isolation. The present study aims to delineate the extensions of the economic layer used for brick’s raw material in Sulaymaniyah Province. For this purpose, the ERT and IPI integrated with physical and geochemical analyses were carried out in three separate locations nominated as 1, 2, and 3. The ERI and IPI survey was conducted in these locations by using a Wenner-Schlumberger array with electrode spacing equal to 5 meters. The 2D data were processed, interpreted, and modified to depth view as 3D estimations for each location. The resistivity range of clay for the brick industry was revealed according to the 2D ERI model of the Aso brick quarry and the suitability of this clay was assessed depending on geotechnical parameters, chemical composition, and mineralogical analysis. It is found that the resistivity values of clay range between 7 and 11 Ωm and silty clay from 11 and 13 Ωm, which are suitable for the brick industry. Additionally, the three locations are suitable for clay or silty clay and locations 1 and 2 are economically acceptable since the clay (or silty clay) layer is exposed to the surface. There is an economic quantity in the three surveyed locations estimated as approximately 240000, 330000, and 160000 m3 for locations 1, 2, and 3, respectively. Further, the IP survey is found to be the most suitable technique used with ERI to indicate the exact boundary of clay mass due to its high capability of electrical storage. The most optimal amount of the chargeability of suitable clay layers is found as equal to more than 5 mV/V and silty clay from 0.9 to 5 mV/V.

This research aims to define the mineralogical composition of recent sediments that were deposited around the Al-Teeb River basin in the east Missan Governorate and try to determine the provenance or the source of these sediments. The study area represents the southeastern edge of the Mesopotamian Plain and is part of it. 15 samples were collected from eight stations of recent sediment that was deposited around the Al-Teeb River; two field works are covered (December 2019 and August 2021). Mineralogical study of the sediment after separating the light and heavy minerals by heavy liquid Bromoform in order to determine the mineralogical composition of the studied samples by using the petrographic microscope the light mineral fraction composed (95.5%) of the total mineralogy. The light components of these sediments consist mainly of quartz about 25.31%, feldspars (potash and plagioclase feldspar) about 9.53%, sedimentary rock fragments (carbonate rock fragments up to 33.39%, chert rock fragments 7.65%, evaporates fragments, 7.31%), (igneous rock fragments, and metamorphic rock fragments about 6.94%). The major component of the heavy minerals residue is opaque minerals with a range of 36.76% and non-opaque minerals with a range of 63.24%. The non-opaque minerals are mainly of chlorite 7.42%, pyroxenes composed of both orthopyroxene and clinopyroxene 6.37%, amphiboles composed of hornblende, glaucophane, and tremolite 7.02%, (mica: biotite and muscovite) 9.81%, zircon 7.54%, tourmaline 5.1%, epidote group 5.91%, rutile 4.5%, kyanite 2.2%. The sediments have two types of stability: moderately stable and ultra-stable. The mineralogical composition shows that the major sources of these sediments are; the river terraces and flood plain of the river in the Mesopotamian Plain, another source of these sediments is the aeolian deposits that separated from sand dune fields in the studied area, and outcrops of ancient sedimentary formations in the southeastern of Iraq as specified by the incidence of the carbonate rock fragments.

The Albian-Early Eocene tectonic evolution of the Zagros Foreland Basin of the High Folded Zone in the Iraqi Kurdistan region has been studied based on the recent foreland basin system concept. This study showed that during the cretaceous (Albian – Cenomanian) there was a geodynamic shift from a passive margin to a foreland basin system phase, not to an active margin phase as mentioned in the previous studies. The advance of the continental margin of the Arabian-Nubian Plate (ANP) toward the subduction zone imposed a tectonic load leading to the form of a flexural wave. The consequences of the last tectonic event were reflected by the continuous deposition of the Balambo Formation. in a foredeep depozone. This happened concomitantly with a flexural emergence of the continental shelf further to the west forming a forebulge depozone represented by the deposition of reefal facies of the Qamchuqa Formation. These geodynamic changes are considered here to represent the Megasequence boundary between the Tectonic Megasequence (TMS) of AP8 and AP9. The last sequence of the passive margin was the Qamchuqa Formation Which is called the Pre-Orogenic Carbonate Platform and was separated from the Bekhme Formation by regional unconformity (Megasequence boundary). The latter is represented by the Lower Sequence of the foreland basin system, which is called the Syn-Orogenic Carbonate Platform (SCP). During the Middle Campanian, the Zagros foreland basin started with the underfilled stage, and it was entirely clear by the end of the Cretaceous comprising a broad threefold subdivision of depositional realms that translated into three stratigraphic units known as trinity underfilled units of foreland basin system. The lower carbonate unit, the pelagic and hemipelagic unit, and the upper flysch clastic unit are represented by Bekhme, Shiranish, and Tanjero Formations respectively. All of these units were superimposed during basin depocenter migration and became younger toward the southwest in front of progressing the orogenic wedge toward the Arabian Craton. During the late Maastrichtian to Paleocene – Early Eocene, the Zagros foreland basin underwent a transition from underfill to fill the stage. Deep exhumation of the orogenic wedge and ophiolite assemblage had supplied the clastic sediment of the Kolosh Formation into the basin covering the foredeep and most of the forebulge and backbulge depozones.

This study is prepared to constitute an isotopic database of Deuterium (δ2H) and Oxygen 18 (δ18O) for groundwater and its relationship with the isotopic footprint for surface water The 311 samples of groundwater were collected between 2013 and 2021 and analyzed using a Liquid-Water Isotope Analyzer (LWIA). The study covered different regions of Iraq, including the Western region (Al-Anbar), Northern region (Kirkuk), Central Region (Samarra, Shirqat, Khanaqin, Baghdad, Karbala, Najaf, Diyala), and Southern region (Samawah، Nasiriya, Diwaniyah, Basra). In addition, the 208 surface water samples were collected from different sources including (the Tigris, Euphrates, Diyala, and Shatt Al-Arab) rivers during the same period. The isotopic measurements showed a linear relationship between the two stable isotopes (δ18O, δ2H) with a slope of 7.38 and an excessive deuterium reach to (-9.4597) compared with the excessive value of the domestic rain line of (14.15). It is defined according to the local meteoric water line equation (LMWL δ2H = 7.7035 * δ18O + 14.158), which characterized a fingerprint of groundwater and showed the impact of the climate on it. The study showed a significant interaction between groundwater and surface water of the Tigris and Euphrates Rivers in the Southern region of Iraq, due to the aquifers in these areas being close to the surface, with depth ranges between (6 – 40 m), and high porosity that simulative of the sedimentary plain characterization. The samples of these areas calculated the highest and the lowest value for δ2H of (12.04‰) and (-36.14‰) respectively. A similar result was found in the western regain. This region recorded the highest value of δ2H (-4.42‰) and the lowest value (-42.2‰), the depth of the wells ranged between (2 – 22 m), which explains the relationship between the groundwater and the Euphrates River. However, the study indicated that the wells in Diyala Governorate, have depth ranges between (10 – 70 m) and were not affected by rainwater or Diyala River, with the highest and lowest value for δ2H of (4.66‰), (-38.54‰), respectively. On the other hand, the highest and lowest values of δ2H were recorded in the Khanaqin area with a value of (-13.48‰) and (-32.67‰) respectively.

Geological investigations are among many essential studies that should be carried out before deciding the location, type, and size of a dam. Without proper geological investigation, the sitting of the dam will cause serious hazards during construction and the commissioning of the dam. In this paper, the effect of site geology on the profitability of Cheragh-Veis Dam is evaluated. The dam is an embankment (rock-fill) type with crest length and height of 274 and 67 meters, respectively. The reservoir’s volume is 88 M3 meters which is mainly used for supplying drinking water and agriculture irrigation. The dam is located to the southwest of Saqez City in Kurdistan Province, Iran.
The geological setting of the dam site includes a sequence of igneous rock of diorite and metamorphic rocks of schist type. The intrusion of hydrothermal solutions through the joint system of the rock mass has a great effect on the disintegration of the schists rock especially on the left abutment. The disintegration of the rock mass is expanded up to 10 m from the surface with a permeability of more than 10 lugeon. Therefore, the strength of the rock mass beneath the dam's core was improved by establishing 4400 m consolidation grouting.
Permeability of rock mass below 10 meters was less than 3 Lugeon, and 1400 meters' grout curtains were installed to ensure the water leakage stoppage from the dam foundation and abutments.

The concept of temperature change is closely related to climate change. Global warming is one of its most prominent manifestations, and the effects of this will be significant on the climate. It will lead to an increase in the intensity of the air cycle, the encroachment of climatic regions towards the poles, an increase in the frequency of extreme weather phenomena, a change in the distribution of heat and rain in different cities of the world, and a rise in sea levels and the threat of most coastal areas. The research aims to determine the variation in temperature, the amount of rain, and its distribution system in the (Basra, Thi Qar, and Missan) during the period (1998 – 2020), and diagnosis of changes in temperature, rain amount, and their cause, as well as its distribution system by analyzing the trend of change in the annual averages of temperature and annual rainfall amounts for the same study period.
The results of spatial analysis using GIS for monthly temperature average data for the same period indicated that the general trend of temperature distribution in all study stations is high, and the peaks during the months (June, July, August, and September), where we notice a large and clear increase, especially in recent years, if compared with rates in previous years. As for the rain data analysis in Iraq, the study found that it was limited to five months (Nov., Dec., Jan., March, April), and October month, which represents the beginning of the rainy season in most monitoring stations, and the month of March, which represents its end, did not record any amount of rain, and this means that the depressions which Iraq exposed to during these two months are unable to produce heavy amounts of the rain because of their shallowness, from the spatial distribution of the amount of rain in the study area that the rainfall rates are reduced to the highest level and its irregular distribution, and therefore reflected in the decrease in water resources in the areas under study. A large amount of daily precipitation in Iraq is due to the recurrence of three atmospheric depressions the (Mediterranean, combined, and Sudanese) depression. These responsible depressions are distinguished by their differences from one region to another, the short duration of their stay and recurrence, the weather conditions that dominate them, and the pressure patterns accompanying them in the upper atmosphere layers. Or some of these depressions reach dryness or are accompanied by non-rainy clouds. This makes Iraq’s rains few, leading to many repercussions on climate, the environment, humans, and various activities.