Iraqi Bulletin of Geology and Mining

Groundwater and seasonal Al-Teeb River are the main sources of water in the study area, which is characterized by arid to semiarid climate. The hydrochemical study involved the analysis of major cations and anions, trace elements and physical properties; the total dissolved solids (TDS) and pH, for 16 groundwater samples and 4 river water samples of the period 2014 – 2015.
Groundwater samples were collected from 14 wells from the Quaternary unconfined aquifer, in addition to 2 well samples from the Tertiary confined aquifer. The water from the river and from the groundwater of the Quaternary aquifer is classified according to the TDS as moderately brackish water, whereas, the groundwater of the Tertiary aquifer is less saline and some wells are classified as fresh water. Moreover, the type of water for most samples is (Na – Sulphate).
Chemical analyses of trace elements of all samples show an increase in the concentration of lead, nickel and cadmium that exceeds their standards limit according to the World Health and the Iraqi Standards, whereas iron and manganese exceed their standard limits in some samples. Piper diagram classification shows that the water type for all samples is earth alkaline with an increase proportion of alkalis (Na2+ + K+) and prevailing sulfate and chloride ions. These result are the same for both surface and groundwater samples for the two seasons. Such water is mostly unsuitable for human and building uses, but it is suitable for livestock and permissible for irrigation, with the exception of two samples from the Tertiary aquifer which are almost suitable for all purposes other than human consumption.

"Galal Al-Dura" is a small drainage basin of an area of 1035.4 Km², located at the middle part of the eastern borders of Iraq, south of the town of Mandili. This basin is a small seasonal stream, locally called as "Galal Al-Dura”. It is drained in "Hour Al-Shibicha" to its southwest, which is a part of Tigris River basin. The studied basin is investigated to examine the influence of tectonic activity through analysis of the geomorphic indices computed using Geographic Information System (GIS).
The results of the calculated geomorphic indices indicate that both the of Asymmetry Factor (Af), and Basin Shape (Bs) indices show relatively high tectonic activity, whereas, the Hypsometric curve and the Hypsometric Integral (Hi), valley floor width to height Ratio (Vf), stream length-gradient (Sl), and mountain front sinuosity (Smf) indices, indicate that the old stage of the stream shows less tectonic activity. This low tectonic activity is characterized by a landscape with very subdued relief associated with low uplift rates, due to the weak sediments type of the alluvial fan that cover large part of the basin. Furthermore, the relative tectonic activity index (Iat) is found to be 2.33 (within class 3), which suggests a moderate tectonic activity in the basin. Two hundred and thirty eight structural lineaments, based on GIS aspect spatial analyst tools are drawn manually; their bearings are measured and represented as rose diagrams.

Wilcox and United State Salinity Laboratory (USSL) diagrams have been applied in the current study to evaluate the available water wells in the area surrounded Saqlawiyah town and to determine its suitability for agricultural purposes. To achieve this goal the Electrical Conductivity (EC) has been measured and Sodium Percent (Na%) and Sodium Adsorption Ratio (SAR) have been calculated based on the chemical analysis of Ca22+, Mg2+, Na+, K+. EC values show that 8.33% of the available water well falls in the tolerable class, 33.33% under intolerant class and 58% in health hazard class. The USSL diagrams show that (50%) of the available well water in the study area is not suitable for irrigation as it belongs to the very high salinity hazard category (C4). The remaining water well samples are belonging to high salinity hazard category (C3). According to the classification scheme of Wilcox irrigation water, the majority of the well water samples (about 50% of water samples) fall under unsuitable category and 41.66% under a doubtful to unsuitable category. Other percentage of the water samples, which represents that of well No. 12 fall within good to permissible category. Therefore only this water can be used for irrigation purposes in the study area. This is because the well lies near the river, where it may get a direct additional recharge.

In this study, five electrode arrays in 2D imaging surveys were tested through synthetic model to determine the most successful array in imaging the subsurface shallow targets. These arrays are Pole-pole, Pole-dipole, dipole-dipole, Wenner and Wenner-Schlumberger. The numerical modeling was made through two shallow walls buried in clayey deposits. The results showed that the dipole-dipole is the most suitable electrode array when both vertical and horizontal changes are present in the subsurface. This study indicates that the Wenner-Schlumberger array might be a good compromise between the Wenner and the Schlumberger and not with the dipole-dipole arrays in areas where both types of geological structures are expected, due to the increase of depth function of Schlumberger array with depth, while it decreases rapidly with depth with the dipole-dipole array. Therefore, it is recommended to use the dipole-dipole array for shallow investigations and to use Wenner-Schlumberger array in greater depths.

The study area is characterized by arid climate, covering some 160 Km2 of dissected Middle Pleistocene alluvial fan and lies 6 Km southwest of Karbala City. Tectonically, it lies along Abu Jir Fault on the western margin of the Mesopotamia Foredeep. This work aims to study and analyze the Middle Miocene – Recent stratigraphic sequence utilizing Vertical Electrical Sounding (VES) in order to determine the possible presence of groundwater aquifers. The resultant type curves include a variety of earth models, ranging from 3 to 8 layers. Two contour maps of groundwater are presented with average aquifer depth of 38.1 m, and average resistivity of 11.4 Ωm. Analysis of the electrical anisotropy coefficient for the sequences overlying the aquifer indicates that both the resistivity – anisotropy, and thickness – anisotropy relationships follow polynomial functions. Furthermore, the anisotropy coefficient is more sensitive to resistivity variation than bed thickness variation. The occurrence of water saturated clay beds and marls (i.e. high conductivity) within a stratigraphic sequence render the electrical medium anisotropic. The map of the electrical anisotropy indicates that the high values in the northern half of the study area may be attributed to the presence of claystone beds. A lack of gypcrete alteration in this area, coupled with low topographic relief supports the hypothesis that the flow of rain water saturates the underlying claystone beds. Results of drilling show the aquifer to be confined, and overlain by impermeable dry claystone beds, of relatively high resistivity. However in the northern region, the shallow (more porous) upper units of the same claystone sequence are water saturated (by rainwater infiltration) giving rise to similar low resistivity values to the aquifer.
It is concluded that the geoelectrical models are highly affected by the tectonic and structural setting of the study area, as indicated by the depth offsets of vertically contiguous resistivity responses. In addition, the marl beds, which underlie the aquifer bearing zone, exhibit a negligibly small resistivity contrast with the aquifer, such that in many models its response is integrated with the aquifer as a single electrical layer. The resultant isopach maps of aeolian sand (top soil) and gypcrete indicate the eastern and southeastern parts of the study area to be most useful for agricultural development.

Sherwana castle, located 3.25 Km to the southeast of Kalar, was subjected in 22 November, 2013 to earthquake of magnitude 5.6 degree on the Richter scale. This event took place about 12.25 Km to the northeast from the castle. It caused damage to constructions especially in the second floor and within the areas around the castle. The event is followed by aftershocks that continued for two months; their influence is noticed in Khanaqin city and the Iraq – Iran border. Three historical events and 412 recent events within 50 Km radius in the area are documented. Their magnitudes range between (1.2 – 5.6) degrees. Seismotectonic map of the area shows a good relationship between the distribution patterns of epicenters to the geologic structures of the region. Isointensity map is constructed and shows the intensity to range between (I – VII) according to the Mercalli scale. Fault plane solution of 16 events in the study area indicates thrust with some strike slip and normal faulting along NW – SE planes.

The application of Multi-Channel Analysis of Surface Waves (MASW) has increased
re4cently in seismic geotechnical engineering and environmental fields. The extraction of Vs
from the phase velocity of Rayleigh surface waves using MASW technique is relatively fast,
more economic, easier to perform in the field and reduces the number of exploratory wells.
The study showed the significance of using MASW to extract shear wave velocities (Vs) from
the phase velocity of Rayleigh surface wave for the near-surface layers to a depth of (30 m)
by acquisition, processing and interpreting the MASW data. Therefore, 1D profiles for the
seismic shear wave velocity has been estimated in the study area. Besides the mathematical
relationship between shear wave velocity and several geotechnical parameters: Poisson's ratio
(σ), Material index (V), Stress ratio (Si), Concentration Index (Ci), maximum load capacity (qu), Effective Angle of Internal Friction (ø), Shear modulus or Rigidity (μ) are
obtained. The results of this study indicated the presence of three layers of rocks. The first,
the upper layer, corresponds to recent superficial deposits. The second, the middle one,
corresponds mostly to the river deposits composed especially of river terraces and clays while
the third, the lower layer, corresponds to the upper part of the Fatha Formation, which is
mostly composed of marls. Also in this study, important relationships were found between the
shear wave’s velocity and other geotechnical parameters. The study therefore recommends
using these relationships for future projects as it can be used in engineering geology to obtain
preliminary results on soil characters.

Sampling sites, were selected from Injana and Fatha Formations. The two studied areas are located within the province of Salah Al-Din. The first one is of Fatha Formation clays in Nukhaila area (N) in the Himrin anticline which lies about 40 Km the south of Tikrit city. The second is located within the southeast of the Khanoqa plunging anticline where Injana clays are well exposed. The results of chemical analysis showed that the studied samples consist of SiO2, Al2O3, Fe2O3, CaO, MgO, TiO2 and SO3 as well as losses on ignition (L.O.I). The physical properties of the studied samples revealed that these are of sandy clayey type and muddy clayey type and characterized by their medium plasticity and can be formed easily.
Dough is made from the studied clay samples after grinding it to size 1.00 and 0.77 mm. then adding 15 – 18% of water and spheres are made manually to about 18 – 20 mm size.
The chemical analysis showed that the studied samples do not fall within the limits of swelling type therefore, mixtures are made from these clays by adding to them 7% sawdust, 2% of waste motors oil and fluxing materials such as Na-bicarbonates (NaHCO3) and spheres are made manually with the same size as above.
The evaluation test results are related to density , water absorption and apparent porosity of the firing and match global studies on light weight aggregate revealing the suitability of Fatha clays of Nukhaila area (N) for manufacturing light weight aggregate after adding 7% sawdust and 2% Na-bicarbonate. The clays of Injana Formation (K) in Khanuqa area, however, has failed and showed no conformity with international results, especially regarding density.