Iraqi Bulletin of Geology and Mining

This study focuses on identifying the relative age in rock sequence of the Ratga Formation (Swab Member), Iraqi Western Desert. To achieve this goal, five samples are collected (mainly limestone) from the Keyhole KH7/7, at a depth between (119 – 130). Nineteen species belonging to eleven genera of calcareous nannofossils are described. The recorded assemblages identified from the stratigraphic succession of this formation confirm Early Eocene (Early Ypresian) age by the biozone Tribrachiatus contortus Interval Biozone CP9a.

Facies analysis, depositional environments and diagenesis of the Paleocene – early Eocene sequence at southwestern Iraq is studied in ten boreholes. The whole sequence is carbonate – evaporite bounded by unconformities and incorporates Umm Er Radhuma, Rus and Jil Formations. The sequence comprises grey clayey dolomite, dolomitic marl, nodular or bedded evaporites, and crystalline limestone representing vanished evaporites and dedolomite. Six lithofacies are recognized in the studied sequence extending from shore towards the basin, these lithofacies are: 1) Evaporites Lithofacies; 2) Laminated Dolomite Lithofacies; 3) Non-laminated Dolomite Lithofacies; 4) Sucrose Dolomite Lithofacies, 5) Massive Fossiliferous Dolomite Lithofacies and (6) Phosphatic Arenite Lithofacies. The evaporites are formed in a lagoon as sabkha cycles and subaqueous shallow marine evaporite. Possibly the evaporite nodules grew under the sediment/water interface under the lagoon. The sulphate could have grown by mixing of waters of different salinities. The evaporitic basin seems to have shifted its geographic position with time. Several diagenetic processes affected the sequence, such as neomorphic replacement, dissolution, dolomitization, sulphate development, vanished evaporites and dedolomitization. Some of these processes obliterated the primary textures.

Al-Ajeej valley drainage basin is located in the northwestern part of Iraq. Tectonically, it is in the Al-Jazira Subzone, within the Mesopotamian Foredeep of the Unstable Shelf of the Arabian Platform. This basin is filled by the soft sediments of the Quaternary Period overlie the clastics of the Injana Formation of Late Miocene age. The entire Al-Ajeej basin is comprised of three contiguous sub-basins namely; Al-Badee, Al-Khazrajia and Al-Hamal sub-basins which occupy 80% of the northern and southeastern parts of the basin. The drainage network of the entire Al-Ajeej basin is delineated using the Digital Elevation Model (DEM) 30 m resolution of Iraq, to examine the influence of tectonic activity through an analysis of the geomorphic characteristics by the benefit of the hydrology tools in the geographic information system (GIS). The analyzed indices are; the Asymmetry Factor (Af), Stream Length, Gradient Index (Sl), Hypsometric Integral (Hi), Basin Shape (Bs), Valley Floor Width to Valley Height ratio (Vf) and Mountain Front Sinuosity (Smf). These six indices were classified and combined to yield the “Relative Active Tectonics” Index (Iat).

According to the (Iat) results, the entire Al-Ajeej basin and its three subbasins were classified as “High” to “Moderate” active tectonics. These results are due the effects of the existence of Sinjar Anticline in the northern most part of the basin and the subsurface extensional structural features. The tectonic activity of Al-Ajeej basin and its sub-basins are reduced to the class of "Moderate" active tectonics, because most of the basin area (about 90%) are filled by soft sediments of the Quaternary Period and the low-resistance clastics of the underlying Injana Formation, in addition to the plain topography and arid climate conditions, despite the effects of Sinjar structure and the subsurface structural features.

The study presents the 2D and 3D mapping of the Mesopotamia Foredeep Basin, Iraq, and the adjacent areas using integrated cartographic approach of multi-source data visualization by Generic Mapping Tools (GMT), R language and QGIS. The geomorphological and geological mapping is based on multiple datasets containing raster and vector layers of the geological, geophysical, topographic, lithological and geodetic data captured from the open source repositories and resulted in 8 new maps. This study develops and presents an integrated cartographic method combining the use of various tools for different tasks in data visualization: QGIS for geological mapping, GMT for mapping geoid, gravity anomalies, 3D mesh visualization and 2D topographic mapping, R language (libraries 'raster' and 'tmap') for modelling relief (slope and aspect) of Iraq. The topography shows variation in data from minimum at -69 m below sea level in the Arabian Gulf, to maximum at 3754 m asl in the NE of Iraq. The map of geologic units of Iraq shows dominating types are Quaternary (Q) and Tertiary (T) that roughly divide the country into two segments (SW and NE). The Mesopotamia Foredeep Basin is dominated by Quaternary (Q). The 3D model of the Iraqi relief presented perspective view of the Mesopotamia Foredeep Basin and Zagros Mts with azimuth rotation at 165°/30°. The geoid undulations increase in NW direction: the lowest, negative values of geoid (-17 m) are over the Arabian Gulf which reflects the continuum of the Indian geopotential minimum. Maximal values of geoid reach 19 m in the SW and NW. The Mesopotamia Foredeep Basin has geoid variations ranging from -15 to 5 m showing correlation with topographic depressions. Free-air gravity model shows correlation of the values with topography proving general trend of the deficit of landmasses causing the negative or lower values in gravity. The values of Faye's gravity anomalies differ from minimum at -124.945 mGal to maximum at 327.724 mGal. The Mesopotamia Foredeep Basin has clearly negative values. The generated cartographic outputs (8 new maps) contribute to the increase of knowledge on the geomorphology, geology and distribution of geophysical anomalies of Iraq with a special focus on Mesopotamia Foredeep Basin. The technical research questions covered by this study relate to the cartographic data formatting, processing, integration and modelling using thematic multi-source datasets covering Iraq. The paper contributes both to the cartographic aspect of integrated mapping and to the regional studies of Iraq, Middle East and the Mesopotamia Foredeep Basin.

Processing and qualitative interpretation of the radiometric data in the Hit – Abu Jir area, west Iraq, is carried out in the present work. The data is analyzed and separated to its residual and regional (background) maps. The regional maps show an increase in radioactivity background towards the northeast, while the residual radiometric anomaly maps show consistent and semi continuous belt of radioactive anomalies along the Euphrates River basin and mostly at the southern and western sides of the basin. The radioactivity in the study area is connected with certain lithological and stratigraphic units, located within the carbonate rocks of the Euphrates Formation (Lower Miocene) as well as around spring-water deposits. A comparison between radiometric map and geological map is executed; showing radioactivity range of each geologic formation. A correlation is carried out between two geologic sections and the radiometric map which shows conspicuous change in radioactivity level at the contact of different geologic formations. It is concluded that the structural setting of the study area played an important role in increasing the concentration of the radioactive elements and controlled their location and extension.

Stable isotope analysis of oxygen (δ18O) and carbon (δ13C) is applied to samples from the Cretaceous – Paleogene boundary (K/Pg boundary) sequence at five localities (Chinarok, Dokan, Dartw, Deramazan, Qalbaza) from Kurdistan Region of NE Iraq. The boundary is located within a thick section of flysch sediments belong to the Tanjero Formation (Maastrichtian) and Kolosh Formation (Paleocene). The purpose of this work is to give an insight into the significance of the isotopes signals in paleoclimatic and paleoenvironmental changes across the boundary zone. Stable isotopes of oxygen (δ18O) and carbon (δ13C) were calculated for three samples at each examined locality of a previously well determined K/Pg boundary sequence using nannofossils. The resulted (δ13C) during Maastrichtian shows negative shift in the samples of the Chinarok, Dartw, and Deramazan localities and the other two localities have positive excursion. This indicate rise of sea water temperature for the first group of samples, i.e. rise of water temperature close to K/Pg boundary. The other two localities have controversial isotopes signals. For the early Danian samples, the Dokan, Deramazan and Qalbaza localities have positive signals with clear increase of the ratio value, the other two localities show positive excursion. This implies a drop of water temperature for the first group which is compatible with global climatic changes, whereas the other two shows contrasted signals. The oxygen isotope ratio (δ 18O) shows similar variable signals among the examined localities. During late Maastrichtian and up to the K/Pg boundary the oxygen isotopes ratio (δ 18O) at four localities (Chinarok, Dokan, Dartw, and Deramazan) show relative drop of value indicating relatively warmer temperature. This drop continue through the early Danian time in two localities (Dokan and Dartw) while the other three have positive excursion suggesting cooler sea water. The heterogeneity of the isotopes signals among the studied localities could be explained in term of environmental effects alterations such as diagenesis or other sedimentation processes. Additional possible explanation is related to the variable sampling spacing at each locality, which could generate mismatching results during correlation.

Artificial ornamental stone is actually a composite material, prepared by mixing polymeric materials with various stones such as sand, crushed dolomite and ground gypsum. This study aims to evaluate local geological raw materials and determine their properties and mineral contents as fillers with polymeric materials. Like the commercial industrial practices, such products contribute to reducing environmental problems compared to other building materials that need to be burned when preparing. In the present work, the raw materials used are local quartz sand, dolomite, and gypsum which are mixed with unsaturated polystyrene in different proportions, and formed by casting. The molds are treated at 90 °C for one hour to obtain a good cohesion between the granules of fillers and the resin. The results are variable depending on the type of filling. Each material used required an appropriate mixing ratio of polymer based on the grain size of the filling materials and their properties. The appropriate proportions of polymer for dolomite, sand and gypsum samples are 25%, 20% and 30%, respectively. Generally, all raw materials used are considered successful for structure clay non-load-bearing tiles according to the requirement of the American Society for Testing and Materials (ASTM) No.C56-71.