Iraqi Bulletin of Geology and Mining

This study deals with the biostratigraphy, microfacies and depositional environments of the rocks of the Dammam Formation (Eocene) encountered in Borehole No.1 in South Samawa, Southern Desert, Iraq. Seventy four samples were studied and three formations were identified, they are from the oldest to the youngest: Rus Formation (Early Eocene), Dammam Formation (Middle – Late Eocene) and Euphrates Formation (Early Miocene). Different species of the foraminifera were identified within the Dammam Formation, two biozones were recognized; they are from the older to the younger:
- Nummulites gizehensis Zone of Middle Eocene (Late Lutetian) age
- Miliolids – Peneroplid Assemblage Zone of Late Eocene (Bartonian) age
The first biozone indicates Middle Eocene age for the Middle Member of the Dammam Formation and the second biozone indicates Late Eocene age for the Upper Member of the formation.
The Dammam Formation revealed three microfacies depending on the fossils content and lithological characters, these are from top to bottom:
- Dolomitic Wackestone – Packstone Facies
- Foraminiferal Dolomitic Packstone Facies
- Nummulitic Dolomitic Packstone – Floatstone Facies
The depositional environment of the Dammam Formation was determined by application of the environment triangle depending on the species of different groups of foraminiferal assemblages, which show that the depositional environment of the Dammam Formation extends from shelf sands area (winnowed edge sands FZ6) and the shoal to the open platform area (shelf lagoon open circulation FZ7) and its continuation to the restricted platform area (restricted circulation inner shelf and tidal flats FZ8).

The stratigraphy of Ashdagh anticline is insufficiently described previously by geologists; hence the present study describes and differentiates the Oligocene units from Miocene units in the aforementioned mountain. The differentiated rocks in Ashdagh anticline are Early and Middle Miocene units of Euphrates, Dhiban and Jeribe formations, which are located between the overlying Middle – Late Miocene rocks and the underlying Oligocene rocks (Kirkuk Group). These units may have been previously mentioned as possible exposed rocks, like Euphrates and Jeribe formations, but Dhiban Formation has not been mentioned before.
For ascertaining these formations, stratigraphy, lithology and fossils content are utilized. The Euphrates Formation consists of two lithologies: sedimentary breccia (6 m thick), which may have been brecciated by solution, and about 3 m of limestone contains Borelis melo melo index fossil. Jeribe Formation consists of grey limestone, which is slightly marly, about 2 m thick and contains Borelis melo curdica. Dhiban Formation consists of anhydrite and chalky limestone, about 2 m thick.

The area includes the locations of Ar'ar, Ma'ania and Al-Bireet in southwest Iraq. The area is bounded by 30o 40' – 31o 40' northing and 41o 40' – 42o 50' easting. The available gravity and aeromagnetic maps are analysed with the aim of producing a geological picture of the subsurface. The gravity map is filtered to produce a smooth regional map that amplifies the broad anomalies over Ar'ar area and Ma'ania area. The filter also gives a residual map that shows sharp local anomalies over Ar'ar area such as, Khaliga and Ashoria as well as a series of long anomalies trending N – S in the Bireet area. Over Ar'ar area, both the magnetic and the regional gravity anomalies are interpreted together so as to have a better constrain on the solution. The interpretation shows that the anomalies are related to a single source within the basement. A sheet of possible basic igneous rock occurs mainly within the basement but its top penetrates the overlying sediments by about 0.5 Km. Such model is seen to satisfy the gravity and magnetic observations at the surface.
The residual anomalies over Ar'ar area are explained by up warping of Lower Cretaceous rocks in addition to probable faulting on top of the upwarp. The residual elongated undulations that trend N – S in Bireet area are explained by correlation with the seismic section in the southwest as due to parallel folds in the lower Cretaceous and older strata. The difference in the trend of these residual anomalies in Bireet area from that of Ar'ar area is explained in that the latter folds are to some extent influenced by the deeper sources trends.

Iraq is located in the northeastern corner of the Arabian Plate, which is in collision with the Iranian (Eurasian) Plate. The contact between the two plates exhibits active seismicity forming active Zagros Seismic Belt. Mosul city and surroundings, although being far enough from this active seismic belt, still suffer from many earthquakes, which can be felt in a diameter of about 100 Km, the center being in Mosul city.
On the 11th of March 2013, at 5:58 pm, Monday a shock was felt in Mosul city and its surroundings to the northeast, north and northwest. The shock lasted for 5 seconds and was registered in Mosul Seismological Center with magnitude of 4.9 degrees on Richter scale. Two other shocks were recorded after few days. People in the villages located north of Mosul have heard high roaring, which accompanied the shock. Many old buildings, among them the church of Tell Asquf village was cracked and the plaster of the church's dome fell down in fragments. Many other mud huts and some buildings showed severe cracks in many other villages. No rupturing on the Earth's surface was reported in the involved areas. No live causalities and/ or wounded people were reported.
In this study, the historic seismicity of Mosul and near surroundings is reviewed. Few events, including historical earthquakes are mentioned too. Details of the present earthquake are given with documentary photographs. The effect of a reverse fault is thought to be the most reliable source for the shocks. Moreover, a fourth earthquake hit the northern part of the area; this was not recorded seismologically, therefore, field data were used to estimate the magnitude, using special charts, which indicate the estimated magnitude.

During the period 15 March to 15 May 2011, 436 surface soil samples have been collected systematically based on the grid net in Al-Nasiriya Quadrangle (sheet NH-38-3, scale 1: 250 000), Mesopotamia Plain, and analyzed for Cr, Ni, Pb, Zn, Co, Cu and U, to re-evaluate the environmental conditions and concentration of the analyzed elements in the soil to detect any pollution, and to determine background levels and distribution of heavy metals in the studied area. The mineralogical analysis shows that for non clay minerals, quartz is the most abundant mineral, followed by calcite, feldspar, halite, and gypsum. For clay minerals; the most abundant mineral is montmorillonite, followed by palygorskite, illite, and kaolinite. The geochemical results show that the distribution and concentration of the heavy metals in the studied soils is within the average concentration given for the reported world soils of arid and semi arid regions, and the soil of the studied area is still free from pollution, except Pb in some local areas, which shows higher concentrations than those reported for world soils. In general, the concentrations of Cr, Ni, and Co are high, which is mainly due to the influence of igneous and sedimentary complexes in Turkey and Syria, derived by the Euphrates River and Injana and Dibdibba formations inside Iraq, as well as the clastics derived from northeast Iraq by the Tigris River and its tributaries, which show their influence in the Mesopotamia part of the river basin.

An empirical method using Rock Mass Rating (RMR) and Slope Mass Rating (SMR) has been applied based on field observations and measurements, and laboratory tests to estimate the strength of rock mass and to assess the stability of rock masses on slopes forming the edges of Al-Salman Depression, located 130 Km southwest of Samawa city, South of Iraq. This procedure is beneficial for acquiring better understanding for the influence of the geological and rock strength parameters, and the mechanism of rock failure on slope stability analyses and processes of open cast mining and quarrying.

ield observations and measurements were carried out at seven sites along the edges of Al-Salman Depression, where some rock slope failures have occurred. The seven studied sites comprise the rock slopes of the Middle Member of the Dammam Formation (Middle Eocene), which consists of alternation of white, grey and yellowish grey, dolomitic limestone, occasionally, nummulitic and chalky limestone.
Slope mass rating is calculated based on values of Rock Mass Rating and joint and slope orientations. The calculated RMR values involve Class C of Fair Rock Mass and Class B of Good Rock Mass. The calculated values of SMR are within Class II of Good and Stable; in most of the studied slopes, but only one site (site 4) is within Class III of Normal, Partially Stable. The calculated results match some of the site conditions.

Carrier flotation was applied to upgrade low grade montmorillonite claystone from Wadi Bashira deposit, Western Desert, Iraq, wherein calcium carbonate represent the main impurity.

In this study, polymeric particles were used as carrier materials and the effect of different parameters (oleic acid concentration for pretreatment of carrier particles, pulp-carrier particles contact time, pulp solid concentration and carrier amount) on the efficiency of the beneficiation process were investigated. This was followed through the measurement of CaO content of the treated claystone. According to the test results, an optimum operating parameters were established 15% solid concentration, 4% oleic acid concentration, 4:1 carrier particles: solid in pulp and 15 min contact time. At these conditions montmorillonite clay concentrate containing 2.5% CaO was achieved from about 14% CaO in the untreated sample. Subsequently, the CEC was enhanced, it increased from (60 – 89) meq/100g.

The groundwater is one of the most precious of all natural resources, particularly in arid and semi-arid lands. Generally, the Arabian Peninsula is one of these lands, where present-day rainfall is scares and limited to mountainous areas. The rest of the land must depend on other sources of water, especially groundwater. The groundwater in the Southern Desert is relatively deep and brackish. For this purpose, a project report has been submitted to GEOSURV to explore new sources of high quality water in an area that lies at the western and southern parts of Al-Salman Depression in the Iraqi Southern Desert (Al-Bahadily, 2012).
The purpose of this scientific note is to explore the groundwater that may be present as fresh water in perched aquifers, which occur near the ground surface within the carbonate beds. It is achieved by electrical method through studying the lateral changes in resistivity.
The present study includes performance of two electrical measuring lines, located at a distance of about 5 Km from the southern and western rims of Al-Salman Depression. The studied area is defined by the coordinates 44° 15' to 44° 45' E and 30° 00' to 30° 45' N.