Iraqi Bulletin of Geology and Mining

The Najmah Formation was known only from subsurface sections in Iraq. But, the regional and detailed geological surveys in the Iraqi Western Desert revealed its presence as surface outcrops, widely distributed along the Eastern and Northeastern rims of Rutbah Uplift. It extends from east of Rutbah to about 140 Km, crossing Wadi Amij, and then northeastwards crossing Wadi Hauran near Qasir Muhaiwir. Lithologically, the Najmah Formation consists of two parts. The lower part consists of clastics, whereas the upper part consists of carbonates.
Fauna like: Clypeina jurassica FAVRE, Calponella sp., Conicospirillina basiliensis MOHLER, Salpinoporella selli (CRESENTI), Coscinoconus alpinus LEOPOLD, Kurnubia palastiniensis HENSON, K. wellingsi HENSON, Haurania deserti HENSON, H.amiji HENSON, Pfenderina trochoidea SMOUT, Valvulina jurassica HENSON and Protoglobigerina sp. are present and are indications of Late Jurassic (Malm) age. The exposed sequence indicates deepening upward cycle starting with shoreline facies and ending with middle shelf facies.

The lower part of the Qulqula (Radiolarian) Formation is studied in the Thrust Zone, Northeast Iraq (Kurdistan Region). The lower part consists of alternation of four detrital limestone successions (each about 25 m thick (with thick intervals of bedded chert and shale. The limestones are mainly of distinctly bedded and shallow marine in origin. The four successions have nearly the same lithology of peloid, ooid, lithoclastic and bioclastic grainstone and packstone, with rare mudstone and wackstone. The matrix consists mostly of blocky cement and minor amount of micrite (lime mud).
Previously mentioned, that the lower part of the Qulqula (Radiolarian) Formation overlies the Balambo and Kometan formations and a conglomerate bed (0.2 – 2 m thick) separates the two formations. In the present study, the origin of this conglomeratic bed is studied and inferred that it belongs to Tanjero Formation. It is found that, with the conglomerate, slices of the Shiranish Formation occur below the lower part of the Qulqula Formation.
The conglomerate is followed for about 30 Km continuously, from Said Sadiq town to Chuwarta town. The conglomeratic bed, 6 Km east of Chuwarta town, merges lithologically and stratigraphically with the conglomerate beds of the lower part of Tanjero Formation (Maastrichtian). The lithologies of both conglomerates are similar. Both of them consist of variegated chert and limestone clasts, therefore, it is thought that they have the same age and origin and belong to Tanjero Formation. This is inferred by observing lateral combination and similar lithologies of the two conglomerates. The only difference is that the conglomerate of Tanjero Formation is characterized by better roundness and sorting than the concerned conglomerate, in the present study. This difference is attributed to more closeness to the source area. The occurrence of Shiranish Formation and conglomeratic bed of Tanjero Formation below Qulqula Formation is attributed to thrusting of the latter formation above the formers.

The Oligocene gap is considered as one of the major and widespread unconformities and interruption in the sedimentary record in the north and northeast Iraq. In the High Folded and Foothills Zones, the gap extends from Oligocene to the Middle Miocene; in the former zone, it separates Pila Spi Formation from Fat\'ha Formation; whereas in the latter it separates Anah and Fat\'ha formations. The Anah Formation is of Late Oligocene age and is marked by a conglomerate at the base of Fat\'ha Formation. The unconformity is studied lithologically and stratigraphically in six different sections, in these sections the conglomerate has different compositions and textures. Texturally, it is grouped into ortho and polymictic conglomerates, while according to the composition they include conglomeratic limestone, sedimentary breccia and both well and badly developed paleosol. These lithologies indicate different depositional systems and source areas; possibly deposited in different times. From sequence stratigraphic point of view; the studied unconformity indicates a type of one-sequence boundary (SBI) during the sea level fall.

Analysis of remotely sensed data and topographical maps with some field observations have helped in the identifications of fourteen morphostructural anomalies controlling the landscapes and the drainage networks in the strip border between Iraq and Syria, from Fiesh Khaboor to Wadi Al-Ajij. These data are representative of new local subsurface structures. Various geomorphic indications were used in the identifications of these anomalies like, radial drainage patterns, water divides, domelike structure, isolated homoclinal ridges, tonal variations and abrupt change in stream courses and fan surfaces.
Most anomalies detected are aligned Northwest – Southeast and East – West, suggesting the presence of morphostructural trends in this part of northwestern basin\'s of Iraq. A comparison between these anomalies and the available geological and geophysical data enables the definition of two distinct morphostructural domains in the study area.
These data were utilized to draw a regional morphotectonic map of the study area. The map can be used not only for assessing the adaptability of landforms and/ or the sensitivity of geomorphic conditions to the related neotectonic activity, but also for the studying of the relationship between morphotectonic zones and oil exploitation in this area.

Remote sensing techniques and GIS applications, with other available different geological data are essential tools in detecting different types of geohazards. Landsat 7ETM+, aerial photographs, topographic, geologic and geophysical maps of different scales were used to detect geohazard areas caused by karstification in Jazira vicinity, western part of Iraq. Different combinations of many bands like 7, 4, 2 and 5, 4, 2 and GIS extensions are used to achieve the best results, in this study.
The Jazira vicinity, West Iraq, is characterized by a dense karstification, due to exposure of gypsum beds within the Fat\'ha Formation (Middle Miocene). Different forms of karst (sinkholes and dolines) with different shapes and sizes are developed, some of them form salt marshes and the largest one is called Ashqar Salt Marsh. Two main lineaments of NE – SW trend and length of more than 100 Km, with escarpments of heights (8 – 15) m are developed. Collapses in different phases, changing the trend of a main branch of wadi Tharthar and controlling the trend of many valleys are characteristic features within the study area in which a big site is located. Three main phases of karstification are indicated, the latest phase is still active, which may cause many problems to any existing structure or those, which will be build in future. Many potential areas for active karstification and abandoned valleys are detected too.

The present work is concerned with gypcrete and gypsiferous soils in Quaternary and Neogene sediments, studied in two sections near Al-Dor and near Falluja. The study deals with lithology, mineralogy and geochemistry of these sediments and the origin of gypsum and salts. More than 20 samples were collected and studied for grain-size analysis, petrography, X-ray diffraction and chemical analysis of salts and host sediments.
The results show two genetically salt assemblages: an early diagenetic minor concentration of (Na – K – Mg – CO3 – Cl) salts supplied from internal diagenetic solutions and a late daigenetic overwhelming concentrations of (Ca – SO4) salts supplied from external sources. The two groups are negatively correlated. Most of the gypsum-rich soils in the studied sections are related to an in situ SO4 enrichment from groundwater sources, whereas some are of aeolian origin and mechanically transported.

Hydrochemical data are presented to describe the groundwater quality of Fatah Umer – Hazar Kani area, which is located between longitude E 44° 57\' – 45° 12\' and latitude N 34° 40\' – 34° 57\', about 100 Km southeast of Kirkuk city in northeast of Iraq. The present study revealed that the Bai Hassan Formation and Quaternary sediments are the main aquifer system, in the studied area, which supplies the region with water, whereas the Injana Formation is the second aquifer system. The hydrochemical properties of the groundwater show the dominance of Ca – HCO3 type in the aquifer system. The chemical weathering of the rocks is the major mechanism that influences groundwater quality.
The EC values increase towards the central part of the studied area along the groundwater flow direction, because most of the low salinity waters enter the studied area from its northern parts and flows towards the central parts carrying dissolved ions. The low transmissivity of the beds and clogging nature of the sediments permit intermittent flushing and hence the dissolved ions sustain longer and reactions take place within the aquifers. The hydrochemical properties of the groundwater samples are compared with the world standards for drinking, irrigation and livestock, for evaluation purposes. All groundwater samples are suitable for drinking purpose, except the Tapa Sawz, Kanimaran and Simaq samples, because nitrate concentration exceeds the acceptable level and reached the polluted level. All samples are suitable for irrigation and livestock purposes.

Gravity and magnetic surveys were carried out in Wadi Shalgha, east of Erbil, North Iraq to identify and delineate subsurface structures. The survey extends along 250 stations with spacing about one kilometer between each two adjacent stations.
Interpretations of Bouguer gravity anomaly combined with total magnetic field data revealed information about the general subsurface structures and their depths in the involved area. Different analytical approaches were applied to isolate and study the subsurface structures. Magnetic interpretation also showed negative regional anomaly zone within the basement that may be attributed to major movements affecting the whole area, and may affect the overburden sequence.
Tectonically, the studied area is situated in the Chamchamal – Butmah Subzone, which forms the northeastern marginal part of the Foothill Zone and it is structurally the highest part of the concerned zone, which may reaches about (7.5 – 8.5) Km depth. Applied interpretations for both methods concluded that the studied area is a zone of subsided area within the basement, along Wadi Shalghah and forming submerged structure, which characterizes this subzone. This structure may have been influenced by the last Alpine collision and final folding and thrusting since the Late Paleogene – Early Neogene.

The reducibility of Al-Hussainiyat pisolitic iron ore with coke and some alkali carbonate additives was investigated. The variable parameters studied are: temperature, time and type and amounts of alkali additives. Initially a precalcined ore of particle size range (–850 +177) micron mixed with coke (–75) micron was reduced in the temperature range (850 – 1000)° C at variable time (60 – 150) minutes. The effect of alkali carbonates (Na2CO3, K2CO3 and CaCO3) on reducibility was next studied at the same temperature conditions above for (150) minutes. Reduction time and the amount of additive in the coke ore mixture was varied (1 – 5) % of the ore weight.
The experimental results show that, reduction temperature, reduction time and additive amount substantially influence the reducibility and higher degree of reduction was accordingly yielded. The best results were obtained at 5% additive at 1000°C .The effect of additives was found in the following order: CaCO3 > K2CO3 > Na2CO3.

The Ground water, in the study area is found within two main hydrogeological basins, affected by structural conditions such as folds and faults. The first basin is within Bai Hassan and Mukdadiya formations, it is located northeast of Baba Dom, which extends from northwest to southeast, whereas the second basin is within Quaternary sediments and Bai Hassan Formation, it is located southwest of Baba Dom.
The ground water of the first basin is suitable for all uses; it is of carbonate group and family Ca – bi-Carbonate, whereas the groundwater of the second basin is not suitable for human uses, but suitable for other uses, except in some regions, it is of sulphate group and family Ca – Sulphate. Water origin in both aquifers is mainly meteoric.