Iraqi Bulletin of Geology and Mining

Palynological analysis of a sediment core of two meters depth from the eastern shore of Razzaza Lake (Karbala Governorate, Iraq) provides the first late Quaternary palaeoclimatic record for the western Iraqi desert region. The lake sediments contain pollen and spore taxa including Graminidities, Palmaepollenites, Polypodium, Onobrychis, Convolusia, Artemisia, Quercus, Retitricolpites tuberosus, Alnus, Chenopodiacea, Plantago, Cuscuta, Pinus, Laevigatosporites ovatus, Laevigatosporites discordant, Littorella uniflora and Anthemis maritimum as well as foraminiferal test linings, acritarch, dinoflagellates and fungi. The pollen diagram suggests eight palaeoecological zones for the late Quaternary period in this area. The palaeoclimate seems to have changed during the last 40000 years through periods of warm and wet climate with Mediterranean savanah forest, pluvial periods with summer rainfall, semi-arid cold climate with steppe vegetation and warm arid desertic climate. Dense vegetation once occupied the catchment area of this depression and at times it was filled with water to form a lake that reached a depth of 16 m. as its level stood at 32 m. (a.s.l.).

Two early Cretaceous bauxite deposits in Northern Arabian Peninsula are studied in this paper; the Zabira sratiform deposits and the Hussainiyat karst deposits. The textural constituents are similar in both deposits; colloform grains (pisoids and ooids) are dominant, but they are better developed in the stratiform bauxite suggesting higher maturation. Boehmite and gibbsite are the only bauxite minerals; the former is dominant in the karst bauxite whereas the latter is dominant in the stratiform bauxite. Various amounts of kaolinite are retained in these bauxites. Hematite and anatase are accessary minerals. The former is more enriched in the stratiform bauxite; inherited from source rocks.
Compared to source rocks, Fe, Ni and to some extent Co were depleted during bauxitization in both types of bauxite deposits, whereas Ga and Zr were enriched together with Al. Uranium was depleted in the stratiform bauxites and enriched in the karst bauxite relative to source rocks, whereas Cr behaved oppositely; both elements are controlled by oxidation potential during bauxitiztion. The hidden karst bauxites have suffered less diagenetic and epigenetic modifications relative to the exposed stratiform bauxites. Resilication is one of the diagenetic modifications found in the stratiform deposits only. Epigenetic calcite, alunite and gypsum were introduced later in both deposits under arid climate.

Gypsum is a well known problematic rock for engineering constructions. The Fatha Formation (Middle Miocene) is a widely spread formation in Iraq. One of its main lithological constituents is gypsum, beside marl and limestone, which occur in cyclic repetition within the formation. Due to high dissolving ability of the gypsum by water, different karst features are developed within the formation. These features, especially when are below surface, may cause severe damages to the constructions which are built on them. Detailed geological mapping of a site, north of Iraq, revealed many surface indications for detecting subsurface karst features that have caused true problems during excavation of the site.

The study deals with the geochemistry of subsurface brecciated rocks encountered in four boreholes in Al-Tinif area, Western Desert of Iraq. The study aimed to investigate the geochemical characterization of these rocks in both vertical and lateral extensions to explore any indications of magmatic activity in the area.
Chemical analysis of 88 core samples (pre-selected and analyzed) from the four boreholes drilled in the area are used. The analysis included the following oxides:
SiO2, Al2O3, Fe2O3, CaO, MgO, TiO2, Na2O, K2O, P2O5, L.O.I and some trace elements:
Mn, Ni, Co, Zn, Cu, Pb.
The data are statistically treated for frequency distribution, mean, standard deviation and correlation coefficient. The results show that the investigated breccia represents a mixture of two main mineralogical phases with variable mixing ratios (20-50%). These are the lime phase which represent Ratga Formation of Eocene age, the other phase represents a ferro-magnesian alumina-silicate composition reflecting the assemblage of the basic and ultrabasic minerals cited in these rocks by the petrological and mineralogical study, previously carried out.
This study reached the conclusion that the investigated breccia may represent a pyroclastic rock originated in situ from magmatic activity in the area and not derived from the volcanic rocks in Syria and Jordan located close to Al-Tinif area. Their origin may be related to a high fluidity volcanic activity in the area.

The results of the exploratory works for uranium during (1978-1987) in the Abu- Skhair area, Najaf Governorate have shown inhomogeneous uranium distribution in the main U-bearing bed, where significant variation was noticed in various locations. Factors controlling this inhomogeneity was not explained.
The results of this study revealed multiple causes for the inhomogeneity of uranium distribution in the main bearing layer at Abu - Skhair deposit. They could be summarized as follows:-
 Influence of faults on groundwater movement.
 Changes in groundwater velocities due to faults led to enrichment of uranium in water as a result of transportation from some localities and deposition in others.
 Influence of porosities of bearing layers on uranium concentration.
 Influence of lithological properties (organic materials and clay substances) of the bearing layer in capture and precipitation of uranium ions.

Zircon and rutile show anomalous concentrations in the heavy mineral fraction of the Ga’ara sandstone (Permocarboniferous) which crops out in the Ga’ara depression, about 40 km north of Rutba town, western Iraq. The Ga’ara sandstone is quartz arenite of fluvial origin and is characterised by high textural and mineralogical maturity.
The heavy minerals are concentrated in the size fraction ranging from 45 to 200 microns representing 0.03 to 4 % of the sandstone and occur as irregular and small pockets. They are mostly opaques (goethite, hematite, ilmenite and leucoxene) and ultrastable transparent minerals (zircon, rutile and tourmaline).
Chemical analysis of 1327 channel samples for zirconium and 1640 channel samples for titania showed that background and threshold values for Zr and TiO2 are 210 (ppm), 950 (ppm), 0.15% and 0.7%, respectively. Eighteen locations were sampled representing the richest and thickest pockets and the heavy minerals were separated and counted in various size fractions. Zircon showed either unimodal distribution with respect to grain size and is richest in the size fraction finer than 63 microns, or bimodal distribution and is rich in the size fraction finer than 63 microns and 71-100 microns. Rutile content showed unimodal distribution with respect to grain size and is richest in the 71 - 100 microns size fraction.
Zircon and rutile were separated from five samples by gravitational and electromagnetic methods. The purity of zircon concentrate is 90 to 95% with recovery 52 to 86% whereas the purity of rutile concentrate is 85 to 90% with recovery 56 to 95%.

In this paper, a qualitative classification for the rocks that produce Marmor and their distribution regime in Iraq is given for the first time. Five types of the Marmor are recognized in Iraq: Marble, Granite, Orthomarble, Gypsum Marmorean (Alabaster) and Travertine Marmorean. The regularity in distribution of their sources in Iraq can be related to the control of the tectonic framework of the Arabian Shelf and the volcanic activity in the center of the tectonic activity of the Tethys.
The rocks that produce Marmor in Iraq are shown on a map of scale
1:10 000 000 to elucidate the following distinctive provinces: Mountainous, Mesopotamian and Desert, depending on the relationship between tectonic framework, source rocks and their minerals content and physiographical divisions. The first province includes three neighboring districts: Thrust Mountains, High Mountains and Low Mountains. The second province includes two neighboring districts: Jazira and Mesopotamian plain. The third province includes two neighboring districts: Western Desert and Southern Desert. According to this regime of distribution, the following districts have the source of certain types of Marmor:
- The Thrust Mountains District is the main source of Marble, Granite and may be Travertine Marmorean.
- The High Mountains and Desert Districts are the source of the Orthomarble.
- The Low Mountains and Jezira Districts are the source of the Gypsum Marmorean (Alabaster).
The rocks that produce Marmor in each district are characterized by limited yield due to the effects of local tectonic activity and the heterogeneous digenetic processes as well as the effects of the local weathering factors.

Beneficiation tests of feldspar from sands of Dibdibba Formation in Al-Najaf vicinity containing 14.0 % feldspar (1.35 % K2O and 0.75 % Na2O) have been carried out. The effect of collector type, collector quantity and pH on feldspar flotation with respect to grade and recovery were examined. Mixed fatty amine and primary fatty amines were used as collectors. MIBC was used as frother in the presence of kerosene. The results obtained indicate that a feldspar concentrate (85 % feldspar) containing 8.4 % K2O , 4.2 % Na2O and 0.85 % Fe2O3 can be obtained with a recovery of about 84 %.

The Iraqi feldspar deposit is a new raw material for industry, which may contribute to the development of local ceramic industry. Following the discovery of the feldspathic sands in the Najaf Plateau with an average of 15% feldspar, attempts were made to upgrade the feldspar content by selecting specific size fractions by dry sieving.
The results of this study showed that the (+4mm) size fractions may contain up to (36%) feldspar, and reach an average of (24.20%) in the (+0.71mm) size fractions with a recovery of (45%). The upgrading of the feldspar was accompanied by reduction in some impurities such as Fe-oxides, magnesia and sulfates, and increase in the quartz feldspar and rock fragments contents. The (+0.71mm) feldspar-rich sands were successfully used in the manufacturing of floor ceramic tiles and sanitary ware in the State Co. of Glass and Ceramic Industries in Ramadi (Iraq).