Iraqi National Journal of Earth Science

Based on geological Data obtained from some deep wells in khleisia anah- Ramadi area western Iraq, The distribution of the upper cretaceous Tayarat and digma formations and there facies in discussed the tayarat formation representing shallow water deposits of the lite campanian is recorded over all the area of study
Tectonic movment during maastrichtian created the anah graben in which deep sea sediments of digma formation deposited
Regression of the sea started during early maastrichtian, led to gradual exposition of the northern middle and finally the western parts of the studied are.
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Facies distribution and paleogeography of lower tertiary deposits in khleisia anah – Ramadi area western Iraq

Menuites fresevillensis ( seunes, 1890a) is recorsded and described for the first time from the shiranish formation (late campanian - maastrichtian), NW iraq, these diagnosis were made on hte basis of planispiral involute shell and compressed whorl section (oxycone), with the mean ratio of whorl breadth to whorl height (wb:wh) attaining 0.4 the shell is moderately ornamented by numerous ribs which mostly arise on the umbilical wall becoming strengthened toward small bullate

as due to the strategic importance of basrah city, south of iraq, the architectural development of the city requires a great deal of studies of the geo technical properties .engineering behaviors and classification of the soil bearing strata represented by the quaternary deposites for such purposes a number of (121) sites distibuted randomly all around the city through (491) boreholes of depths (10-48) M below mean sea level are studied.
the data are obtained from the test results of (SPT), grain size distribution and the atterberg's limits
the quaternary deposites are classified into two main groups : firstly is the cohesive deposites represented by the recent clay and silty clay as well as alhammar formation deposits. secondly is the cohesionless deposits represented by sands of dibdiba formation
according to the consistency of cohensive deposits and the compactness of the cohesionless deposits, ten strata can be identified starting from the ground surface , as follows.
hard brown silty clay, very stiff brownish-grey silty clay or clayey slit, stiff grey clayey slit, medium stiff grey clayey slit laminated with slit, soft grey clayey slit laminated with slit, medium stiff grey clayey slit, stiff grey clayey slit, very stiff grey clayey slit & sandy clayey slit, hard brown clayey slit and very dense grey sand with slity sand

Facies and paleogeography map of the lower tertiary (Paleocene –eocene) sequences, In khleisia- anah- Ramadi area, are presented. During Paleocene-lower early Eocene most part of the study area were exposed, whereas shelf deposits of the Akashat formation accumulated in the western part. Transgression of the sea started during upper early Eocene, led to deposition of deep basinal sediments of the Jaddala formation in the western part (Anah Graben) and shoal nummulitic facies of the Rutga formation in the southern part.
Gradual progress of the transgression overall the study area during middle and late Eocene led to depositionof the jaddala formation.

samples from the outcropping rocks of bai hassan, muqdadyia , injana, fatha and pila spi formations have been collected for density measurements supporting a gravity survey that has been planed over the area on either side of the greater zab river . the results are compared with densities measured from seismic stacking velocities made over four long seismic lines that have shot previously in the same area, furthermore a single velocity log from a well that penetrates these formations has been used, the results are presented and discussed

The study put stratigraphic frame work of late Paleozoic era (Devonian – permian ) in Iraq, which include six formation from older (pirispiki, kaista, ora, Harur, ga'ara and chai Zairi) which are examined in eight borehole sections distributed in north, south west and western part of Iraq. These section have been compared with type section, which mostly lies in north Iraq.
The studied sequences manily composed of siliciclastic and mixed ( carbonate – silliciclastic) which belongs to two megasequences each of them corresponding to the 1st order cycle of global sea level change.
These megasequences are Kaskaskia sequence (late Devonian-early carboniferious) which represented by the pirispiki, kaista, ora and harur formation.
The lower part of absaroka sequence (late carboniferious-permian) which represented by ga'ara and chaizairi formations.
Time lines don’t match with the facies boundary and different from age of type section for some
formations

Paleoclimate of the western desert of Iraq during carboniferous to end of tertiary are dealt with by this study. Significant climatic criteria are drawn from analysis of various geological data related to the formation representing the stratigraphic coloum of the western desert of Iraq global paleogeographic maps of the western desert of Iraq are also used.

Al-Fat'ha formation at mishraq structure considered from the hydrogeological point of view as one of the most complicated multiple aquifer, where containing cavities and the water zones formed by the action of dissolution and alteration of evaporate rocks to sulphur, the thickness ranges from 1 m to 10 m and their number exceeding 10 zones. Temp. profiles were observed in 20 hydrogeological boreholes to locate the distribution of water bearing zone vertically by the infection in the temp. profiles
Temp profiles are classified into four types according to their patterns of variation in temperature gradient with depth. It has been found the degree of inflection and the changes in temperature gradient have a relation with the hydraulic properties and ground water movement horizontally and vertically between the aquifers.

The Mosul depression is a topographic low which lies between the elevated anticlinal structures of bashiqa and ain safra to the northeast and atshana and nuwaigit to the southwest. This depression, some 30 km wide, is floored by the alluvial deposits of river tigris and its tributary khoser and other quaternary deposits.
The present study is aimed at detecting the presence of any subsurface undulation or faulting associated with the depression. Eight points of depth electric sounding are put over a line that trends Ne-Sw across the depression
Measurements were made using collinear symmetrical Schlumberger electrode arrangement with a maximum Ab distance of 1500 m. continuous correlation of the result with lithological logs of nearby wells are made.
The results indicate that the traverse crosses a broad shallow sub surface undulations to the east of the tigris. The results also show that the course of the river khosar lies over an important, vertical tectonic plane ( fault ) which separates lithologies of low resistivities to the east of the river from those of high resistivities to its west.

This study deals with reprocessing and reinterpretation of the gravitational anomalies of western Erbil along to traverses running in the area with NE- SW direction across the main zagros trend and over demir dagh structure.
Bouguer anomaly is obtained by reducing all observed data to the mean sea level with reduction density of 2175 kg /m3 which was used by ipc when constructing the gravity map of Iraq.
The observed gravity data has shown local high anomaly superimposed on general negative anomaly which is related to dimer –dagh structure. Graphical separation has been carried out for local anomaly separation.
Two dimensional model was applied using a computer program to calculate the anomaly which is due to the variation in rock densities within tertiary and u.
Cretaceous. Two geophysical model were constructed for the geological interpretation of each traverse.

The geophysical / electrical resistivity survey has been carried out for the left side area of tigris river in Mosul city. The aim was to detect the extension of wadi agab fault, which has already been referred by previous studies using remote sensing methods.
The present survey has no shown any indication of the fault in the study area. The study has also shown the presence of subsurface channel of tigris river between al- Mothanna and al-hadba.

Two main sets of joints were found in pila spi, alfatha, and injana formation in bahsiqa area.- These sets are ac & BC joints. Joints system were also found but in minor amount.
The paleostress δ1 which was responsible for the formation of AC and hko acute about A joints, was trending north – south before and during the formation of the major anticline (from middle Eocene – pre- Pliocene).
The bc type of joints was formed during the fold formation by two mechanism types ( hinge deformation and limp deformation). In these two mechanism, the axis δ1 was trended northeast – southwest and north – south respectively. At the pre – folding time the hko acute about b developed to form subsurface strike slip displacements which influenced the geometry of bahsiqa anticline.