Volume 20, Issue 2, Autumn 2020


Research Paper

Study of the Quaternary Deposits at the East and West Shoulders of Mosul Dam Using Azimuthal 2D Resistivity Imaging

Mahmood Al-Fadhel; Marwan Mutib

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 1-17
DOI: 10.33899/earth.2020.170353

The field survey included three geoelectric traverses on the eastern side of the Tigris River parallel and perpendicular on the axis of the Tairah anticline consisting of seven sites of ( Azimuthal Resistivity Tomography; ART) located above the Quaternary depositions in the southern flank. Two traverses  were also conducted in the western side of the river parallel and perpendicular on the east Butmah anticline consisting of four sites located above the recent sediments in the southern flank of it. The sites are chosen taking into account the consideration of the geological, tectonic and topographic data of previous studies and current field reconnaissance trips.
A sympathetic analysis of the resistivity tomography is performed in nine azimuths of the above mentioned locations using fifteen repetitive processing attempts and the mean root squares ranged between 5.8% -11.7%. The eastern side of the study area with different directions indicates electrical horizons, the first reflects a variable resistivity which represents accumulations of top soil, the second band of high resistivity which reflects the river terraces constitutes, while the third horizon represents the clear extension of the mud and limestone deposits of Fatha Formation with a vertical conductive zones in the rock layers at some traverses. As well as the ART on the western side of the study region identified three electric horizons: the first with high resistivity reflecting the surface soil layer, and the second domain of low resistivity representing the sediments of the valley slopes and concentrating on the southern limb of Butmah anticline. The third of heterogeneous resistivity values reflects  Fatha Formation deposits covering its exposures at the core of the two anticlines and locating beneath the research traverses.
Using the technology of 2D resistivity imaging reveals that the nine orientations around a central point in eleven locations above recent sediments are represented by river terraces and alluvial deposits on the shoulders of the Mosul Dam. The current study concludes the ability to capture fractures, which is of great importance due to their effect on the displacements of the dam's body and Fatha sediments surrounding it.

Planktonic Foraminiferal Biosatratigraphy of the Eocene – Oligocene Boundary at Sinjar Area, NW Iraq

Hiba Al-Rubai; Majid Al-Mutwali

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 1-18
DOI: 10.33899/earth.2020.170355

The present study deals with the lithostratigraphy, biostratigraphy and chronostratigraphy of the Eocene- Oligocene boundary in three surface sections in Sinjar anticline, northwestern Iraq. Jaddala Formation composed of marl, marly limestone represents deep Eocene facies, Palani, and Tarjil formations represent Early and Late Oligocene sequences. Sixty-two planktonic foraminiferal species belonging to sixteen genera have been recognized which permit the recognition of four Zones; these are from older at the base:  
  Globorotalia opima opima Total- Range Zone (P21)
  Globigerina ampliapertura partial- Range Zone (P20)
  Pseudohastigerina micra Interval Zone (P 19)
Globigerinatheka subconglobata subconglobata Partial Range Zone (P11) (Part).
      
The Eocene- Oligocene boundary in Sinjar area represents disconformity surface, where the deposition ceased in the Middle Eocene (Lutetian) at the end of Jaddala Formation, then deposition started at the Upper Early Oligocene due to rapid wide transgression, leading to the  deposition of Palani (Rupelian) and Tarjil (Chatian) formations, which consist of thinly laminated hard white-pale brown intercalation of marly limestone and marl beds.

Assessment of Limestone of Ibrahim Formation in Zurbatiya Area, Eastern Iraq for Ordinary Portland Cement Industry

Narjis Al-Ali; Sattar Al-Khafaji

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 19-32
DOI: 10.33899/earth.2020.170358

Limestone deposits of Ibrahim Formation in Zurbatiya area, eastern Iraq are assessed as raw materials for the industry of Ordinary Portland Cement (OPC). The deposits are widely exposed in the area close to Iraq-Iran borders. Six samples were collected from selected section of Ibrahim Formation, which consists of a succession of well-bedded white to gray limestone interbedded with gray marl and marly limestone. X-ray diffraction results show that calcite is the dominant mineral followed by quartz and traces of dolomite which appear in limited samples. X-ray fluorescence results revealed a noticeable increase of SiO2, which might be due to the effect of limestone by silicification process, so the rocks are considered to be a siliceous limestone. The other oxides (CaO, Al2O3, Fe2O3, MgO, Na2O, K2O, TiO2, SO3, and P2O5) are within the acceptable limits required for cement industry. Cement chemical parameters indicated that there is a decrease in the lime saturation factor (LSF) and an increase in silica ratio (SR) in comparison with the chemical parameters listed by standard specifications due to the increase of silica content. This increase can be adjusted by adding clays, or any other source of low silica content in addition to use iron and alumina as correcting additive materials for the cement mixture.

Biostratigraphy and Systematic Palaeontology of Late Cretaceous Heterohelicidae Foraminifera from Kurdistan Region North-eastern Iraq

Rawand Jaff; Fadhil Lawa

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 33-63
DOI: 10.33899/earth.2020.170360

The biostratigraphical importance and systematic palaeontology of Early Turonian to Early Maastrichtian Heterohelicidae Planktic foraminifera from Kurdistan region, NE Iraq are described. Some 24 species from 11 genera are recorded. Species abundance and diversity increase from the Early Turonian to Early Maastrichtian, perhaps signifying cooler sea temperatures in the Arabian sector of the Tethys Ocean during the Early Maastrichtian. Despite the long biostratigraphical ranges of some species, the importance of the biserial and multiserial Planktic foraminifers in Late Cretaceous biostratigraphy is emphasized. From a biostratigraphic perspective, heterohelicids are important for the definition of the Campanian-Maastrichtian boundary in Kurdistan region, with Planoglobulina species being especially important in this respect, as they are in Iran, Turkey and North Africa.

Biostratigraphy and Sequence Stratigraphy and Depositional Environment of Kolosh Formation in Dohuk Area, Northern Iraq

Saif Al-Khalaif; Majid Al- Mutwali

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 18-42
DOI: 10.33899/earth.2020.170362

The present study deals with biostratigraphy, depositional environment and sequence stratigraphy of Kolosh Formation in two sections of Bekher anticline, northeastern Iraq by using the planktonic and benthonic foraminifera. Therefore, (48) species of planktonic foraminifera belonging to (14) genera and (34) species of benthonic foraminifera belonging to (19) genera have been recognized. The detailed planktonic foraminiferal investigation permits the recognition of seven well defined biozones and three subzones; they indicate that Kolosh Formation extends from the Early Paleocene (Danian) to Late Paleocene (Thanetian) age. The depositional environment of the formation was studied throughout relying on the variation in the diversity of planktonic forminifera, as well as throughout the ratio of the planktonic foraminifera to the whole mass of foraminifera, and the ratio of planktonic forminifera to the benthonic formiminifera. The lower part of the formation represents the upper bathyal environment, while the middle part deposited within the outer shelf environment, then deposition basin became within the middle shelf area in the upper parts of the formation.
Sequence stratigraphic analysis for the studied sections of Kolosh Formation  delineated three sequences which is interpreted as 3rd order sequences, and it is found that the deposition of Kolosh Formation in the Badi section had been occurred in shallower level for most sedimentation intervals compared to the Linwa section which represents a somewhat deeper marine environment.

Planktonic Foraminifera Biostratigraphy of Shiranish Formation in Piramagroon Anticline, NE Iraq

Ahmed Al-mutiwty; Abdullah Shihab

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 43-63
DOI: 10.33899/earth.2020.170369

67 planktonic foraminiferal species were identified from the Shiranish Formation. On the basis of the stratigraphic distribution of the planktonic foraminiferal assemblages recognited of six biozones within the Shiranish Formation representing an age ranging from Middle Campanian – Early Maastrichtian, these zones are from older at base:
6 -Planoglobulina acervulinoides Interval Zone.
5 - Contusotruncana contusa Total Range Zone.
4 -Gansserina gansseri Interval Zone.
3 - Globotruncana aegyptiaca Interval Biozone.
2 -Globotruncanella havanensis Interval Biozone.
1 -Globotruncana ventricosa Interval Biozone

Analyzing sensitivity and resolution of some electrical resistivity configurations for detecting subsurface cavities using inverted synthetic models by 2D electrical resistivity tomography technique

Zainab Shanshal; Ahmed Al-Heety

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 64-85
DOI: 10.33899/earth.2020.170370

It is important to determine the location, depth and shape (dimensions) of cavities under subsurface in site investigation phase before construction. This study aims to make a study for properties, analysis and comparison of the results of different electrodes configurations that used in 2-D electrical resistivity Tomography surveys to detection subsurface cavities to determining the appropriate and suitable configurations type that must be conduct in the field to obtain best and accurate results. Two-dimensional synthetic models were created for Geoelectrical resistivity of five different geological features, which reflects the common cases of cavities in nature. These models are (narrow, broad, shallow and deep) cavities adding to one model for multiple cavities.  RES2DMOD program was used to create these models, while RES2DINV program used in Inversion method to obtain the true 2-D inverted resistivity sections for six configuration types of electrode array for 2D electrical resistivity technique, after adding a Gaussian noise ratio of (5%). Generally, we are noticed the possibilities of most tested configuration types for determine electrical anomalies, because the high contrast between the cavities and the surrounding rocks resistivities values. In addition, RMS ratio overall does not exceed 5%, hence, this ratio is an acceptable and indicates to the quality of the inverse process. The Wenner array have high sensitivity to vertical resistivity variations, and Dipole-dipole array have high sensitivity to lateral resistivity variations. While the Schlumberger-wenner have high sensitivity in both lateral and vertical resistivity variations Also, it was noted that the efficiency of all types decreasing with increasing depth of cavities detecting, due to the low percentage of contrast between the cavities and the surrounding rocks. The Wenner beta (WB) configuration is the best choice in terms of inversing true resistivity values, Secondly the Pole-Dipole (PD). While in term of determining the location and shape (approximately dimensions) of cavities, Dipole-Dipole (DD), Wenner-Schlumberger (WS), Wenner Alpha (WA), Dipole-Pole (DP) respectively. However, in case of noisy areas, Wenner Alpha (WA) configuration gives the best result.

Geochemistry and Petrogenesis of Dioritic-Gabbroic Pegmatites in the Bulfat Complex, Qala Diza, Northeastern Iraq

Shareef Al-Hamed; Khalid Aswad; Nabaz Aziz

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 64-90
DOI: 10.33899/earth.2020.170371

The pegmatite dikes and associated plutonic rocks stand as a part of the igneous complexes associated with the Bulfat complex, located in the Zagros Suture Zone (ZSZ), NE Iraq. The Bulfat complex is a part of the ophiolite-bearing terranes that are allochthonous sheets. The complex represents the upper allochthon of the Albian-Cenomenian. The study area is located within Bulfat complex of ZSZ, specifically in the northwestern part of this zone and within the second unit of the Penjween-Walash Subzone. The rock samples were collected from pegmatite dike which is located to the northeast of the Darishmana village, the thickness of dike is about 5 m.
Electron microprobe analyses (EMPA) of plagioclase in 8 spots of dioritic pegmatites ranges between oligoclase (An18.00-An28.23) and andesine (An32.53-An33.62). Bulk whole-rock chemical analysis of fourteen samples using ICP-MS analysis reveals alkalinity Index (AI) of pegmatites to be metaluminous (A/NK > 2). Generally, the silica content in these pegmatites is from 46.70 wt. % to 52.67 wt. %.
The relatively flat pattern of REEs is characterized by the slight enrichment of LREEs compared to HREEs indicating the common ancestry of the studied pegmatites. Also, the enrichment of these pegmatites in LILEs (Sr, Pb, Rb) and depletion in HFSEs especially (Nb, Ta, Y) indicate the environment of the island arcs. Moreover, the low ratios of (Rb/Sr)N and (Ba/Sr)N refer to that these pegmatites are derived from a basic origin.
Tectonic discriminate diagrams show that the tectonic environment of studied pegmatites is I-type, which is the oceanic island arcs environment of sub alkaline rocks. The pegmatites of the present study have a genesis relationship with intrusions close to them in the study area; these intrusions are gabbros of Wadi Rashid that represent the environment of E-MORB. Moreover, the gabbros of Wadi Rashid and studied pegmatites are part of ophiolite-bearing terranes, they are found within upper allochthon thrust sheet. The current study of pegmatites reflects the oceanic island arcs environment, this indicates the existence of double island arcs, the first adjacent to the Arabian shelf, and the second close to the middle of paleo-ridge.
Numerous evidences support that the gabbros of Wadi Rashid being as the likely parent to the studied pegmatites such as geochemistry, tectonogenesis, and the close spatial distribution of the pegmatites to the gabbros of Wadi Rashid. Moreover, the studied pegmatites appear to entail further dissection mainly due to the fact that the occurrence of dioritic- and gabbroic-pegmatites with a small-scale in the single intrusion might have its explanation in the liquid associated immiscibility.

Sedimentological and Biological indicators of oceanic anoxic events (1d) inside upper Balambo Formation, L. Albian, northeastern Iraq

Falah Al-Miamary; Ali Al-Jubory; Safwan Al-Lhaebi

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 86-104
DOI: 10.33899/earth.2020.170372

The studydeals with succession from the upper part of the Late Albian Balambo Formation which are composed of fine-grained dark gray to black calcareous shale, limestone and marly limestone rich in sedimentary structures such as lamination, fissility and platy structures. Microfacies analysis revealed that mudstone, wackstone and few of packstone are the main facies in the studied succession. The studied rocks generally are rich in organic matter and pyrite in addition to dominance of radiolaria, sponge spicules and foraminifera with elongated champers maybe “Schackoina” genus. All these characters indicate deposition in marine conditions with reduced or absent-oxygen condition that relate to oceanic anoxic event (1d).

Sedimentological, Paleontological and Mineralogical Evidences for Oceanic Anoxic Event-2 (OAE-2) in the Gulneri Formation (Early Turonian), Northeastern Iraq

Safwan Al-Lhaebi; Ali Al-Jubory; Falah Al-Miamary

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 105-125
DOI: 10.33899/earth.2020.170373

In the current work, the Gulneri Formation (Early Turonian) is studied in three surface sections (Degala, Dokan and Azmir) from northeastern Iraq. The formation is characterized by grey to black color limestone and marly limestone in the Degala and Dokan sections, whereas in Azmir section, fissile marl and marly limestone with pale to reddish color are dominated in addition to few beds, which occasionally contain fish remains, with distinct gray color reflecting the very few amount of total organic carbon in these beds. Microfacies analysis revealed that the formation consists of three microfacies: mudstone, wackestone and packstone. The predominance of dwarfish planktonic foraminifera (Heterohilex) and thin shell filaments particularly in packstone microfacies represent Heterohelix shift event and filament event respectively. In addition to these events, fish remains, radiolarian pyritization, planktonic foraminiferal chambers elongation and glauconite are all refer to anoxic environmental conditions that may have been coincided with the Global Cenomanian-Turonian Oceanic Anoxic Event (OAE-2).

Effect of Tectonostratigraphic Units in Evolving Aqra Anticline Model

Mahmood Al-Sumaidaie; Nabeel Al-Azzawi; Rabeea Znad

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 126-147
DOI: 10.33899/earth.2020.170374

In the current study, a tectonic model for the structure of Aqra Anticline was proposed. The model was dependent on the rock properties, stratigraphic relationships and thickness variations as well as, the model was correlated with other previous studies. The study area is located within the Iraqi Zagros fold/ thrust belt (ZFTB) which represents the northeastern margin of the Arabian Plate.
Stratigraphically, the anticline comprises of formations that are deposited between Early Cretaceous to Pliocene periods. These formations are the Sarmord, Qamchuqa, Aqra, Kolosh/Khurmala, Gercus, Pila Spi, Fat'ha, Injana, and the Makdadiya formations. they were deposited during four Tectonostratigraphic Megasequences (TMS). The older TMS contains formations that were deposited prior the development of the Zagros Foreland Basin, whereas the formations of other three Megasequences were deposited within Zagros Foreland Basin. During those times, the foreland basin was divided into three distinct parts. these are fore deep, bulge, and fore-bulge, which   were discriminated via listric faults, which played as normal and reverse displacements after and before ophiolite obduction.
Some contributions to the tectonostratigraphic model of the area are adopted. They are stages of basin development, determining the time of extension period of the listric faults and detecting the tectonic inversion of these faults. This model is described within the compressional tectonic framework between the Arabian and Eurasian plates.

Paleoenvironmental Study of Khurmala Formation by Ostracoda in Shaqlawa and Dohuk area, Northern Iraq

Mahfoudh Al-Hadeedy; Saleh Khalaf

Iraqi National Journal of Earth Sciences, 2020, Volume 20, Issue 2, Pages 148-164
DOI: 10.33899/earth.2020.170375

   A detail paleoenvironmental study of ostracods fauna to investigated the paleoenvironment of Khurmala Formation for two section Northern Iraq; the first (Hjran section) lies near Shaqlawa city, and the second (Dohuk section) lies near Dohuk city. Based on ostracods study conclude that Khurmala Formation were deposited in shelf environment, about (30 – 200) meter in depth.