Iraqi Bulletin of Geology and Mining

Environment of Iraq was affected by global and regional fallout from the nuclear weapon tests and nuclear accidents. This paper presents the results of studying the deposition levels and distributions of 137Cs, in soil samples collected from 281 sites throughout the Iraqi territory, between the years 1999 and 2003. The objective of this work is to provide regional radioactivity background levels for cesium in surface soils of Iraq. Activity concentration of 137Cs, in the collected surface soil samples were measured. A gamma spectrometric system based on a pure germanium detector was used. The minimum and maximum activity concentrations of 137Cs in the collected soil samples ranged between below detection limit (BDL, about 0.5 Bq/Kg) to 175 Bq/Kg dry soil, with average of 21.9 Bq/Kg. The maximum concentration of 137Cs (175 Bq/Kg) was found in a soil sample collected from Um Al-Waz area near Akashat, within the western part of Iraq. The average concentration of 137Cs in surface soils of the northern part of Iraq, which was affected by Chernobyl accident that occurred in Ukraine in the year 1986, was about 15 Bq/Kg, while it was about 7 Bq/Kg in the surface soils of the southern part of Iraq. The highest average was in the soils of the western part of Iraq, about 33 Bq/Kg. The concentrations of 137Cs in soil samples, with depth were measured in some selected sites. Migration of 137Cs to depth more than 10 cm was not recorded.

Sinjar Mountain is the most conspicuous outstanding geomorphic feature in the central northwestern part of Iraq; it is surrounded from north and south by gently inclined plains. The highest peak attains 1462 m, whereas the elevation of the surrounding plains ranges in height between (407 – 432) m. The mountain forms asymmetrical anticline, almost with E – W trend that has steeper northern limb (45 – 80)° and gentler southern limb (15 – 25)°, its length is about 80 Km, whilst the width is about 20 Km. The oldest exposed rocks belong to Shiranish Formation (Late Cretaceous), which is the main source for development of the alluvial fans, beside many other formations.
A well developed set of alluvial fans can be observed along the northern limb of Sinjar anticline; they extend northwards to (20 – 22) Km, partly out of the Iraqi territory, inside Syria. Generally, four stages of alluvial fans are developed, the fourth being in Syria. Locally, the fans of the first stage overlap laterally forming "Bajada".
The first stage alluvial fans; genetically are of Type I being still active, whereas the fans of the remaining three stages are of Type II; being partly dormant. The formers are of very coarse size sediments, deposited in low water/ sediments ratio with typical fan shape. On contrary the remaining fans have longitudinal shape, mainly of fine size materials, being deposited in high water/ sediments ratio. The age of the first stage alluvial fans is Early Pleistocene, whereas, the fans of the other three stages are of Pleistocene – Holocene age. No pavement and/ or desert varnish were observed in the alluvial fans. The main reason for the development of the fans is the neotectonic movement of the Sinjar Basin, besides the exposures of Shiranish Formation, which are overlain by hard and massive limestone of Sinjar Formation.

The role of the microbes in precipitation of stromatolitic limestone and lime-sand in water of recent spring in the Kurdistan Region, Northeast Iraq is discussed. The spring mouth is forming a small circular lake (350 m in diameter) with slightly acidic water, and saturated with dissolved CaCO3. Due to effect of the microbes and wind direction (and its related currents), the limestone and lime-sand are deposited mainly on the southwest bank of lake (spring mouth). The role of microbes can be seen in forming many types of the microbial limestones (microbialites), which consist of finely laminated (stromatolite) or clotted structures (thrombolite) or both. The existed stromatolite; forms well developed oncoids of different sizes, and micro-oncoids (ooids), which have diameter of (0.1 – 20) cm. The thrombolite consists of irregular clusters (clotted) of ooids (or micro-oncoids) encrusted by microbial micritic layers and separated by voids. On the lake bank, the small oncoids and thrombolites, which form clotted clusters of ooids mass are exposed on the shore, while large oncoids are exposed away from the shore; on the periodically flooded areas. Both types of limestone and lime-sand show the effect of wind energy in developing the rock with certain types of structure and texture; within the examined rocks, which are analogous with Arabian Gulf.

The present study aims to determine the infiltration capacity and some physical properties of soils from some selective locations in Koi Sanjaq city and near surrounding areas, within Erbil Governorate, north Iraq. The exposed geological formations (Pila Spi, Fatha and Injana) and Quaternary sediments have been studied, for this purpose. Pila Spi and Fatha formations are exposed in west, northwest, north, and northeastern parts of the study area, whereas, Injana Formation is exposed in the central, southern, southeastern, and southwestern parts of the study area. The Quaternary sediments cover some of the central parts of the study area, too.
Sixteen locations were selected in different parts of the study area, for sampling and infiltration test application. These locations were selected according to the type of the exposed rocks and existing of the Quaternary sediments. The depth of the infiltration capacity with time, grain size distribution, and Atterberg limits are determined for all the studied locations.
According to f (t) value, the infiltration capacity of the study area is between (Slow – Rapid). The infiltration capacity results indicated that the west and northwestern parts of the study area are characterized by Medium – Rapid rate of infiltration, the northern part is characterized by Medium rate of infiltration. Whereas, the central, east, southeast, southwest and northeastern parts are characterized by Slow – Medium rate of infiltration. However, the southern part is characterized by Slow rate of infiltration. Therefore, west, northwest and northern parts of the study area are considered as a good recharge areas for Koi Sanjaq city, as the Quaternary sediments are concerned, hence it is recommended not to use these areas for urbanization projects; to remain the area as a source of recharge for Koi Sanjaq city. The southern part of the study area is characterized by Slow rate of infiltration capacity, which indicates that it consists mainly of clay. The clay is characterized by high porosity, but low permeability, consequently the rate of infiltration is Low, therefore, this part is not recommended for deep water well drilling, consequently, the population of this part benefits the shallow water wells. The coefficient of permeability also is determined and the results indicated that the coefficient of permeability is High in the northern and northwestern parts of the study area, it decreases south wards.
The study of the grain size distribution of the soil samples indicated that the north, west and northwestern parts of the study area are characterized by increase of coarse grained sediments; whereas the central, south, southeast and southwestern parts are characterized by increase of fine grained sediments. The Atterberg limits (liquid limit and plastic limit) indicated that the soil is generally with low to medium plasticity index.

This study was conducted to assess the bloating characteristics of the calcium montmorillonite claystone from Wadi Bashira in the Iraqi Western Desert and indicate the effect of red kaolinitic claystone and feldspathic sand addition. The materials were formed into pellets, (aggregates) after mixing in different wt% combinations. The results of heat treatment of aggregates formed only from montmorillonite claystone indicated that, bloating incidence occurs at a temperature of (1180 – 1200º C). The bloated aggregates obtained exhibit a considerable low bulk density (1.185) g/cm3¬ and low mechanical strength. All aggregates made from the mixtures (montmorillonite claystone, red kaolinitic claystone with, or without feldspathic sand) showed a good to very good bloating. Also the aggregates made of montmorillonite claystone and feldspathic sand (except that made with 5 wt% feldspathic sand) showed a good bloating. The bulk density of the bloated aggregates obtained was appreciably low (0.54 – 0.7 g/cm3) with water absorption value of (4 – 6.8) %. This suggested that these aggregates can probably used, as lightweight materials in civil works.

Iraqi kaolin of Dwaikhla and Al-Soofi deposits were biobleached using the mold Aspergillus niger. The major discoloring of these clays is due to the presence of iron, titanium oxides and organic impurities. In this work, the Fe2O3 content of Al-Soofi Kaolin was lowered by 28.31% (from 2.19% down to 1.57%), while the Fe2O3 content of Dwaikhla Kaolin was lowered by 31.25% (from 1.61% down to 1.10%). The TiO2 content was also lowered by 33.6% and 27.0% (from 1.16% and 1.48% to 0.77% and 1.08%) for Al-Soofi and Dwaikhla Kaolin, respectively. It was found that the brightness of these clays was improved by the biobleaching process from 47.61 to about 59.59; for Al-Soofi Kaolin and from 63.23 to about 69.08, for Dwaikhla Kaolin. It is also worth to mention that wet sieving of Dwaikhla Kaolin on 45µ sieve improved the brightness up to 70.98.

This paper is concerned with the study of the paleoclimate and paleoenvironmental changes of Bahr Al-Najaf Depression during Late Quaternary; using palynological analysis for the sediments. Samples were collected from two sites (BN1 and BN2), which were chosen in the depression; where 23 and 19 samples were collected from the first and second locations, respectively and studied to determine their content of pollens, spores and marine organisms (Dinoflagellates).
The study revealed climatic and environmental changes in the area during Late Quaternary and seven climatic zones were determined in the studied sequence and correlated with other areas in and outside of Iraq. The climate was pluvial with intervening dry periods in the 18000 years; B.P.
The study indicated as well, some marine effects on the studied area on the commencement of Holocene due to the global transgression. This is based on the presence of marine organisms, (Dinoflagellates).

In this study a field follow-up was carried out to monitor cadmium concentration in the sediments of the Euphrates River and the distribution of this highly poisonous element along the river course, as well as to locate possible sources related to cadmium supply and enrichment in the Euphrates River environment. The analyses of river sediments and mollusk shells collected from 15 stations along the river course in Iraq showed relative cadmium enrichment in the river sediments, in addition to its presence in relatively high concentrations in the mollusk shells of the river. The river sediments contained up to 5 ppm Cd (mean 3.5 ppm) and the mollusk shells contained up to 5.4 ppm Cd (mean 4.8 ppm) compared to less than 1 ppm in unpolluted stream sediments and lake sediments.
The possible pollution sources are discussed including geological nature, industrial waste, agricultural activities and municipal sewage discharge. The results suggest that the contribution of industrial sources to Cd enrichment is negligible; the phosphate fertilizers plant at Al-Qaim has no influence on this phenomenon. The industrial waste-water, occasionally discharged to the river, contain negligible traces of cadmium. The study suggests that other anthropogenic sources may have significant role in the enrichment of Cd in the Euphrates River sediments. These include discharging of irrigation water, rich in phosphate fertilizers, to the river along its course in Iraq, and discharging untreated municipal heavy water (sewage) to the river without treatment from highly populated cities.