Iraqi National Journal of Earth Science

Monotypic shell beds of molluscan skeletal sand are contained in the non-marine, fluvial sequence of Injana Formation of Upper Miocene age-Kand Anticline, as yet undescribed previously. These carbonate beds are characterised only by abundant pelecypod, oyster with scarce and opportunists gastropods and smooth-shelled ostracods. This faunal assemblage is consignable with non-marine low salinity euryhaline fresh, brackish water. The sudden change in their composition and distribution has been influence by salinity variation. The exclusion of normal marine-stenohaline fauna point to their deposition in non-marine setting including interchannel lake initiated on distal floodplain and/or river dominated bay esturay, or fan delta lake-lagoon.

Study of clay minerals (Kaolinite,Iillite and Illite-Smectite mixed layers) in the clastic sediments of the Ghar Formation (Upper Oligocene-Lower Miocene) is the main indicator for the variation of the pore waters responsible for the eodiagenetic processes affecting on
these sediments. Variation of these clay minerals are used also to distinguish the sedimentary environments of the Ghar Formation as transitional environment from fluvial into marine. The genetic relations of these clay minerals and their semi quantitative proportions by XRD and SEM are used also to distinguish the authigenic minerals and their paragenetic sequence.
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A total of 138 core samples were collected from six subsurface sections of Yamama Formation. These sections were randomly distributed in West Qurna and Nasiriya oil fields. The collected samples were analyzed for; Ca, Mg, Fe, Na, Mn, Sr, Pb and insoluble residue using wet chemical analyses, in addition of representative samples were examined by X-ray.
X-ray diffractograms revealed that the bulk samples consist of calcite, dolomite, and subordinate detrital quartz. Whereas, the clay fractions of insoluble residue consist of kaolinite, illite, illite- montmorillonite mixed-layer.The kaolinite percentage shows a marked increase in Nasiriya field (i.e. towards the paleoshorline).
The concentration of Mg and Na progressively increases as water salinity increases. The Fe and Mn concentrations are function of the clay content of the sediments, while the concentration of Sr is largely controlled by the fossil debries. Regarding Pb no systematic trend in its distribution was noted,i.e. it has an eratic distribution.
Ca/Mg molar ratio showed a less effective dolomitization process while Sr/Ca and Fe/Mn atomic ratios proved that Yamama Formation were deposited in a shallow marine-lagoonal-brackish environment.

Several diagenetic phenomena have affected the sandstones of Injana Formation. These include: compaction, cementation (manifested by dominance of carbonate cement with minor silica, ferruginous, and gypsum cements), replacement, recrystallization which noticed by the transformation of micritic matrix and fragments to sparry calcite whereas the alteration appeared through change of feldspar to clay minerals. Most of these diagenetic phenomena are related to eodiagenesis and minor rule of mesodiagenesis (alteration and partial recrystallization and cementation ).

The present study deals with the distribution of major oxides (Al2O3, CaO, Fe2O3, SiO2 wt%), minor oxides (Cl, K2O, MgO, MnO, Na2O, P2O5, TiO2 wt%), trace elements (Co, Cr, Cu, Ni, Zn ppm.) and the consituents of free lime, insoluble residue and loss on ignition in (38) representing different types of portland cement produced at ( 13) Iraqi factories during the interval 1997 / 1998. The study is concerned with variation in the chemical composition in relation to the nature of raw material or raw mix, burning, cooling and storing conditions and the content of major phases in ordinary, sulfate resistance and white portland cement.

The study area is situated near Makhmour district, crossing the Lesser Zab River in (NW-SE) direction and covering an area of about (2000) square kilometers. Using thematic mapper (TM) and thermal band techniques, it was possible to observe thermal spots on the southern part of Qarah Chauq structure and at Wadi Kendinawa. Field samples collected from the southern part of Qarah Chauq structure contained no hydrocarbons. However, using Adope Photo Shop Program, Kendinawa samples showed evidence of hydrocarbons, which were reflected as colour phenomena within the study area. Using the same program, colour separation of hydrocarbons from sulphate minerals was carried out. The present study proves that, it is possible to carry out reliable colour measurements, by the use of thermal band technique, for the investigation of oil pullution in other parts of the country.

Four outcrop samples of Shiranish and Sinjar Formations in Kersi basin on the northern limb of Sinjar Anticline were chosen. These samples are composed of marl, calci marl and dolomitic limestone, in addition to four soil samples were taken from a neighbouring sites.
The study dealt with the effect of weathering on the samples using diluted oxalic acid (0.01M), and the study of the hydrologic activity of Kersi basin using morphometric analysis.
The results showed that there is a linear conformal course for both calcium and iron released from the soil with their equivalent, which are released from the rocks. This was confirmed statistically by a significant correlation coefficient, while magnesium, sodium potassium and manganese do not show neither linear conformal course, nor a significant correlation coefficient between the release of these elements from soil and rocks. Also, the results of morphometric analysis from the shape of hypsometric curve showed that kersi basin is regarded as hydrologically immature basin which means that weathering was active and is related directly to erosion factors occurring in this basin.

Seventy eight planktic foraminiferal species and subspecies were recorded from the Jaddala Formation in some selected wells in western Iraq. On the basis of the stratigra-phic ranges of the recorded foraminifera, the studied sequence is attributed to the Morozovella formosa formosa, Acarinina pentacamerata, Acarinina bullbrooki, Globigerinatheka subconglobata subconglobata, Acarinina rotundimarginata, Hantkenina alabamensis, Truncorotaloides rohri rohri, Globigerinatheka mexicana mexicana and the Turborotalia cerroazulensis cerroazulensis Zones.
The present investigation indicates that the Jaddala Formation is upper Early-Late Eocene in age.
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The area of this work is bounded by Jabal Atshan to the north and wadi Qassab to the south. The study is concentrated on the structure, stratigraphy, aqifers and aquicludes of the Fat`ha Formation from a data collected by many boreholes in the area. Six of these boreholes were periodically measured for groundwater level fluctuations as well as measurements of some hydraulic properties of the upper unconfined aquifer in two boreholes. Some of the physical properties of water such as pH, Ec, BOD5 , COD were performed for the period 15/12/2001-15/5/2002. The study revealed that there were four ground water levels representing four aquifers of different depths. Various water qualities in various boreholes were recorded depending on depths and rock types forming the aquifers. In the best cases, these waters must not used for drinking, but for irrigation to certain crops and animal drinking.