The Iraqi Geological Journal <p>The <strong><em>Iraqi Geological Journal (IGJ)</em></strong> is a peer-reviewed and indexed journal, issued twice a year in English by the Union of Iraqi Geologists (UIG).&nbsp;</p> en-US (Sameer R. Ahmed) (Sameer R. Ahmed) Wed, 31 Mar 2021 00:00:00 +0000 OJS 60 U-Pb ZIRCON DATING OF MIDDLE EOCENE CLASTIC ROCKS FROM THE GERCUS MOLASSE, NE IRAQ: NEW CONSTRAINTS ON THEIR PROVENANCE, AND TECTONIC EVOLUTION <p><strong><em>The provenance of Middle Eocene clastic rock from the Gercus Molasse, NE Iraq was determined by detrital zircon (DZ) U-Pb geochronology. </em></strong><strong><em>The Gercus Molasse in the Iraqi segment of the north-eastern Zagros Thrust Zone provides an ideal example of foreland system evolution with respect to the transition from passive margin to the accretionary complex terrene-flexural foreland basins. The DZ U-Pb age spectra from the Gercus Molasse suggest that the foreland sediments either influx from multiple provenances or are the result of recycling from the accretionary complex terrane. During pre-accretion, however, the radiolarite basin (Qulqula Radiolarite, 221 Ma) located along Arabian passive margin likely acted as an intermediate sediment repository for most or all of the DZ. </em></strong><strong><em>Representative DZ U-Pb measurements revealed that the Gercus clastic rocks </em></strong><strong><em>fall into several separable age population ranges of </em></strong><strong><em>92-102 (Albian-Cenomanian), 221 (Upper Triassic), 395-511 (Cambrian), 570- 645 (Neoproterozoic), 1111 (Mesoproterozoic),</em></strong><strong><em> and lesser numbers of Paleoproterozoic (</em></strong><strong><em>1622-1991 Ma</em></strong><strong><em>) ages. The source of Proterozoic detrital Zircons is enigmatic; </em></strong><strong><em>the age peaks at 1.1, 1.5, 1.6, and 1.9 Ga (Proterozoic) does not correspond to any known outcrops of Precambrian rocks in Iraq, and it may be useful to continue to search for such basement. </em></strong><strong><em>The detrital zircons with age populations at 0.63–0.86 Ga probably originated from the Arabian-Nubian Shield. The age peak at 0.55 Ga correlates with Cadomian Magmatism reported from north Gondwana. The age peaks at ~0.4 Ga is interpreted to represent Gondwana rifting and the opening of Paleotethys. The youngest ages populations at 93 Ma indicate that fraction of DZ were transported directly from the contemporaneously active magmatic arc (Zagros Ophiolite segments). The </em></strong><strong><em>paleogeography and tectonic evolution of the Neogene Zagros foreland basin were reconstructed and divided into two tectonic stages. </em></strong><strong><em>The early stage is defined by the Campanian accreted terranes (i.e. orogenic wedge) form loads sufficient to produce flexural basin with a deepest part is situated next to the tip of the loads.&nbsp; This flexural basin is filled by the flysch clastics of the Maastrichtian– Early Eocene (i.e. referred to by the Tanjero-Kolosh flysch sequence). The late stage is marked by a synchronized modification of the clastics fill of the basin and changes in dip directions to compensate for the reduction of the load by both erosion and extension and the basin, therefore, was sealed by a shallowing upwards depositional sequence ending with the terrestrial Gercus Formation. </em></strong></p> Nabaz Rashid Aziz, Derin M. Sadiq, Khalid J. Aswad ##submission.copyrightStatement## Sat, 27 Mar 2021 00:00:00 +0000 Comparison Between the Classical Classification and Digital Classification for Selected Samples of Igneous and Carbonate Rocks <p>As igneous rocks have widely chemical and mineralogical compositions, there are many ways to classify these rocks. These ways are classical approved methods to give a reliable classification and nomenclature of rocks. Some igneous rocks may be classified by digital image processing to assist in classical methods. Five igneous samples were cut, prepared of thin sections, and polished to classify them by classical methods and digital image processing by ENVI software. Moreover, part of these samples crushed an analysis of major oxides. The current igneous samples have referred to the basic and mesocratic rocks based on the classical methods and this has corresponded to ENVI software. The igneous samples have reflected the leucogabbros when classify them by classical and ENVI classifications, except the G5 sample, which has been referred to as gabbro by ENVI. There is a clear similarity between the classical and ENVI classifications. ENVI classification is a reliable classification to assist the classical methods in the nomenclature of igneous rocks, especially, plutonic rocks, it can be also applied to thin sections of volcanic rocks to classify and nomenclature classification by ENVI has been applied on fifty thin sections of limestones to identify microfacies which are classified beforehand by classical (optical) classification. According to optical classification, microfacies have classified as mudstone, wackestone, packstone, and grainstone. When the digital classification is applied to them, there is no grainstone texture found in these them. Digital thin sections, where the true name of these microfacies is packstone. Therefore, the positive sides of the digital image processing by ENVI software appeared and contrasted to the optical classification which contained some mistakes when applied to the nomenclature of these microfacies.</p> Shareef T. Al-Hamed, Zaid A. Malak ##submission.copyrightStatement## Sat, 27 Mar 2021 13:52:33 +0000 Heavy Minerals Study of Sandstone from the Late Miocene-Early Pliocene Mukdadiya Formation; Kirkuk, Iraq: Implications for Provenance <p>Mukdadiya Formation (Late Miocene-Pliocene) exposed in the northeastern limb of Baba anticline fold in Kirkuk structure. The selected section was located in the Shoraw area, northeastern Kirkuk city, Iraq. Twenty sandstone samples were collected to study heavy minerals. The study indicates that opaque and epidote group minerals forming the main heavy minerals, followed by amphibole, pyroxene, garnet, and chlorite. According to heavy minerals assemblage, the source rocks are interpreted to be composed essentially of sedimentary followed by igneous and metamorphic rocks and the high contents of unstable and metastable minerals confirm their direct derivation from the adjacent primary source. Ultra-stable and metastable heavy minerals relationship indicated that the sandstone of the Mukdadiya Formation is immature and moderate stability and showed that these minerals couldn't be transported for very long distances close to the source area and not represents polycyclic grain. MF-MT-GM Ternary diagram showed that the studied samples fall within the field of active continental margins which is characterized by a relatively high percentage of minerals (MF˃GM) derived from mafic magmatic rocks.</p> Abbas Rashid Ali ##submission.copyrightStatement## Sat, 27 Mar 2021 13:54:51 +0000 Geochemical Study Geochemical Study of Injana Formation and its Tectonic Significances in Selected Areas-Iraq <p><strong>Abstract</strong></p> <p>This study is concerned with geochemical analysis of major oxides; these are SiO<sub>2</sub>, CaO, MgO, Fe<sub>2</sub>O<sub>3</sub>, Al<sub>2</sub>O<sub>3</sub>, Na<sub>2</sub>O, K<sub>2</sub>O, TiO<sub>2</sub>, in addition to MnO. Atomic Absorption Spectrophotometer and Ultra Violet Spectrophotometer tools were used to examine ten samples represented the detritus LOI sediments of Injana Formation in Iraq in two sites which are (S1) site at Dohuk Governorate and (S2) at Al-Najaf Governorate; where five samples for each sites were collected.</p> <p>The chemical results emphasize that the Injana sediment clasts are classified as litharenite to slightly sublitharenite and greywacke referring to immature clasts. Arid paleoclimtic conditions faced sediments which coincide with low to relatively grade chemical weathering. Tectonically, the studied area represents active continental margin with slight trend to passive margin and island arc; whereas those sediments derived from mafic to intermediate source rocks. The provenance of Injana Formation that had been deduced is the Tourus-Complex Zagros Mountains that are recognized by the ophiolitic-radiolaritic and complex igneous rocks.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> Ahmed Abaas Al-Mothen ##submission.copyrightStatement## Sat, 27 Mar 2021 13:58:15 +0000 Three Dimensional Terrain Modeling for Tectonic Geomorphology of Chinara Anticline, Northern Iraq <p>Analysis of the terrain using three-dimensional models offers a deep insight view of ground surface topography and terrain representation. The Chinara anticline is one of the main structures of NW-SE trends for the highly folded zone in northeastern Iraq. The objective of this study is to understand the interrelationship between topography and morphotectonic features using three-dimensional models. This research employed fourth generates principal raster derivative products from the DEM using ArcGIS. To understand the undulating of this anticline with the morphotectonic style, the adaptive equation has been suggested to determine the direction and amount of the main tectonic forces, which can be applied to other undulated anticlines. The values of northeastern and southwestern limbs undulating index UI are 11.7 and 7.8 respectively that indicates the strong tectonic force towards the northeast. Two listric faults have been conducted via the field survey that confirmed by remotely sensed interpretation and DEM products. These listric faults had an intensive impact in comparison with concluded strike-slip faults, and then the Chinara anticline would be less structural undulating in a region of vicinity syncline to Perat undulation. The morphotectonic landscapes reveal that the listric fault has branched into two parts, the first one extending to form the anticline and the other comprises the structural dilemma.</p> Rayan Ghazi Thannoun, Azealdeen Salih Al-Jawadi, Hadeer Gh.M. Adeeb ##submission.copyrightStatement## Sat, 27 Mar 2021 14:03:02 +0000 Geological Modeling for Nahr Umr Formation in Subba Oil Field, Southern Iraq <p>Geological modeling is very important in reservoir study, where it is described the framework of the structure and provided a distribution of petrophysical properties, the geological model helps to comprehend the fluid flow behavior affected by the heterogeneity of reservoir, also it is used to calculate oil initially in place and to choose the new well location in reservoir management. In this study, a geological model is built for Nahr Umr Formation based on data of 11 wells (SU-2, SU-3, SU-4, SU-5, SU-6, SU-7, SU-9, SU-10, SU-11, SU-13, and SU-14), including the location of wells, well tops, also contour map of the Nahr Umr Formation in Subba oil field is utilized. The structural model is constructed for the Nahr Umr Formation, which consists of two domes. The formation is composed of sandstone mainly interbedded with shale. The formation is divided into four units (B1, B2, C1, and C2) depending on well log data, each unit is divided into layers for getting better distribution of petrophysical properties, where unit B2 is divided to the number of layers is higher than other units due to its heterogeneity. The variogram is used as a geostatistical method to predict the petrophysical properties at unsampled locations, experimental variogram is calculated from well log data in a horizontal and vertical direction. The spherical variogram model shows a good fitting with the experimental variogram. Sequential Gaussian algorithm is used in distribution of petrophysical properties in a geological model which shows good petrophysical properties in unit B2 and unit B1, while units C1 and C2 are highly saturated with water.</p> Mahdi Ali Menshed, Huda Daaj Al-Mozan ##submission.copyrightStatement## Sat, 27 Mar 2021 14:05:18 +0000 Distribution of Steranes and Triterpanes Biomarkersas Indication of Depositional Environment and Maturity of Sargelu and Kurrachine Formations in Different Wells Northern Iraq <p>Eight cuttings samples were obtained from Sargelu and Kurrachine formations in different wells at different depths to detect steranes and triterpanes biomarkers as an indicator of the depositional environments and thermal maturity of organic matter. This was accomplished using GC-MS technology. The diasterane/sterane ratio showed low ratios in analyzed samples (BJS2, JKS3, BJK1, JKK4, JKK7) as in most marine carbonate sources, while algal-bacterial organic matter contribution for the samples analyzed based on the predominance of C<sub>23</sub> tricyclic relative to the C<sub>19</sub> tricyclic terpene and the C<sub>23</sub> tricyclic greater than C<sub>24</sub> tricyclic terpane. The Gammacerane index indicated that normal salinity conditions during depositions. The biomarkers related to maturation such as diasterane/sterane, Ts/(Ts+Tm), and C<sub>29</sub>Ts/C<sub>29</sub> hopane show that the organic matter in Ain Zalah well (Sargelu Formation) is within early mature (oil window).</p> Arwa M.S. Al-Dolaimy, Fawzi M. Al-Beyati, Aahed Y. Al-Mallah ##submission.copyrightStatement## Sat, 27 Mar 2021 14:08:32 +0000 Mineralogy and Chemical Composition of Basalt Stone Tools in Some Iraqi Archaeological Sites <p>Basalt stone tools were collected from some Iraqi Archaeological Sites. Twenty-one samples were studied petrographically, mineralogically, and chemical composition. Five samples were from the Gaara Depression north of Rutba town, seven samples from Tarmiya, north Baghdad, seven samples from Dalmij site, east of Diwaniya city, and two samples from Jordan, which were used for comparison. The studied samples were classified into three groups, according to their mineralogy and texture: Group A: Vesicular Basalt, Group B: Dolerite, and Group C: Olivine Basalt. These stones most probably were used as a hand axe, grinder, hammer, and other uses, as well as for buildings, like those used in Qasar Al- Azraq and Umm Al- Jamal archaeological sites in Jordan. These basalt rocks most probably were transported by an ancient man from Harrat Al-Sham, which extends through Syria-Jordan-Saudi Arabia, or from NE Syria through a trade route that connected between source areas and the studied archaeological sites in Iraq.</p> Aqeel Abbas Al-Zubaidy, Hasan Kattoof Jasim, Rami M. Idan ##submission.copyrightStatement## Sat, 27 Mar 2021 14:10:16 +0000 An Integrative Modeling Approach to Estimating Volume of Generated Oil from Lower Cretaceous Sulaiy Formation in Southern Iraq <p>&nbsp;&nbsp;Thermal maturity and petroleum generation capacity of the source rocks of Lower Cretaceous Sulaiy Formation were studied and evaluated via modeling the thermal maturation of ten wells in this study by using the Arrhenius equation for chemical reactions or (time-temperature index of thermal maturation). A thermal maturation map of the Sulaiy Formation shows that it a high maturity level increasing eastward; also, the geochemical analysis indicated suitable organic content in quantity and quality to generate hydrocarbons. The onset of oil migration from the Sulaiy Formation is calculated by this study to be at the end of Lower Eocene time (53 million years ago), and as it is a late hydrocarbon generation and migration; thus indicating mainly vertical migration paths. According to quantitative estimation, the oil generated and migrated vertically from the Sulaiy Formation towards the Lower Cretaceous reservoirs in southern Iraq estimated at 42.6 x 10<sup>9 </sup>bbl. This study elevated the status of the Sulaiy Formation to a major source of oil tapped in the Lower Cetaceous reservoirs of southern Iraq.</p> Basim Fadhil Alkubaisi, Mohammed A. Al-Nuaimi, Amer S. Al-jibouri ##submission.copyrightStatement## Sat, 27 Mar 2021 14:14:02 +0000 Shanidar Cave in Northern Iraq (Kurdistan Region), a National Geopark Recommendation <p>Shanidar Cave is located in north Iraq (Kurdistan Region), it is one of the most well-known caves in the region due to its archeological significance. It is an archaeological site which is located within Bradost Mountain north of Erbil city. In the cave, eleven skeletons of Neanderthals, have been found dating back to 65000 – 35000 years B.C., they were called Shanidar (1-11). The cave also contains two later proto-Neolithiccemeteries. The cave is developed due to dissolution of limestone beds of the Qamchuqa Formation which forms the carapace of Bradost Mountain (anticline). Currently, the cave and the downslopes to the foothills of the mountain are limited by a fence. The cave can be reached by a paved road to the foothills level, then by stepping following artificially constructed leader which is designed and constructed by local materials from stones and wood giving to the leader a natural view. The Shanidar cave is highly recommended to be a national Geopark due to its archeological significance</p> Varoujan K. Sissakian ##submission.copyrightStatement## Sat, 27 Mar 2021 14:16:04 +0000 Subsurface Structural Interpretation of Missa Keswal Area, Eastern Potwar, Pakistan <p>Potwar Basin is although a hydrocarbon prolific basin but shows mixed scenarios regarding the success ratio of the wells. Several wells are producing good but a significant number of wells ended up with a great loss. Missa Keswal area is also a part of the Potwar Basin which was discovered in 1991. The main objective of this research is to find the subsurface structure of the Missa Keswal area with the help of seven seismic lines, 3-D modeling, and the correlation of five wells. Kingdom suite 8.8 is the main software used to delineate the subsurface structure along with some other software. Results indicate that the tectonic framework of the study area is mainly controlled by the Jhelum strike-slip fault and decollement layer i.e., Pre-Cambrian salt. Structural analysis shows that the study area bears NE-SW trending salt cored pop-up anticlinal structure bounded by major thrust fault and back thrust. Patala Formation acts as a source, Lockhart Limestone, Sakesar Limestone, and Chorgali Formation acts as a reservoir while fault surface (often acts a good conduit) and Neogene clays providing a potential sealing mechanism for entrapment.</p> Muhammad Armaghan Faisal Miraj, Muhammad Zubair Idrees, shan shahzad ##submission.copyrightStatement## Sat, 27 Mar 2021 14:18:05 +0000