Iraqi National Journal of Earth Science

Petrographic investigation of Dokan Formation revealed that it consists skeletal grains that are mainly dominated by calcispheres in addition to foraminifera, bio and lithoclasts, ostracods and peloids. The groundmass is formed from micrite with less sparite. Several diagenetic processes have show their imprints on the Dokan rocks. Neomorphism is the more important process which leads to the change of micrite into microspar and then to pseudospar, compaction; both mechanical and chemical is other process that ranges from slight to high compaction and is recognized by fracturing and elongating of calcispheres. Other diagenetic processes include, dolomitization, cementation, dedolomitization, silicification, anhydration and authigenesis. Dissolution leads to formation of several types of secondary porosity; e.g. moldic, Intra and interparticles, vuggy and fracture porosity

A total, 15 chemical variables have been determined from 29 samples representing skeletons of some carbonate secreting organisms from the north west Arabian Gulf. The analysis are reported as percent SiO2, A*l_{2}*O_{3} FeO, CaO, MgO, C*O_{2} P_{2}*O_{5} N*a_{2}*O K_{2}*O S*O_{3} T1O_{2} MnO, NiO, PbO and SrO.

Mineralogical analysis revealed the presence of Aragonite, Low Magnesium Calcite (LMC) and High Magnesium Calcite HMC) as dominant minerals, and quartz. Dolomite and feld- spar as traces. Chemical analyses indicates that the main differences in the constituents of the studied skeletons are controlled by the water chemistry, mineralogy, growth rate, calcification processes and the nature of the constituents.

Two new species of the Ostracede genus Buntonia Apostolescu, 1961 have been described for the first time from the Rataga Formation (Lower- Upper Eocene) and Aaliji Formation (Lower Paleocene-Lower Eocene) west, north of Iraq, namely; Buntonia desrtensis sp.nov., Buntonia aalijiensis sp.nov.

The Jeribe Limestone Formation represents the main confined aquifer withing the area of north Mosul. The formation characterized by high voids, fractures which is affected by karstification. The hydraulic properties of aquifer (Jēribe), transmissivity, hydraulic conductivity and storage coefficient were found by using different methods of analysis of draw down in observation wells. The results showed that the main aquifer (Jeribe) is of high transmissivity and it contains a large volume of water.

The Ostracoda from 89 samples of recent sediments from fourteen traverses along Khor Al-Zubair channel, southern Iraq have been studied.

Forty-two species of marine and non-marine Ostracodes belonging to twenty-eight genera have been recorded, including twenty species recorded for the first time in Iraq.

The distribution of each species is discussed from palaeogeographical point of view in relation to the adjacent and related regions. The affinities indicate distinctive migratory routes; the first from Indian Ocean to the Red Sea and the second route from Indian Ocean to the Arabian Gulf and Southern Iraq, therefore the origin of most of the species in the studied area is indo-Pacific bioprovince.

Clastic facies analysis of Injana Formation in borehole KH8/9 north west Iraq revealed six lithofacies: (1) Pebbly sandstone facies, (2) Cross- bedded sandstone facies, (3) Massive beded sandstone facies, (4) Cross laminated sandstone facies, (5) Parallel laminated sandstone facies, and (6) Mudstone facies. These facies occur as fining - upward cycles within the clastic sequence.
The lower part of the sequence is inferred, on the basis of characteristics sedimentary features to be deposited as transitional intertidal flat. The following phase is dominated by meandering river system including: lag channel, point bar, natural levee, crevasses- splay, floodplain and abandoned channel deposits

Oligocene - Miocene boundary was studied in Sheikh Ibrahim and Sasan areas (west Mosul), where three core holes penetrated six formations of about 150-180 m thick, (Tarjil Fn., Ibrahim Fn., (Hamrin Fn.?), Serikagni Fn., Euphrates Fn.and Dhiban Fn.). According to paleontological studies of the formations twenty four planktic foraminiferal species and subspecies were identified. Four biostratigraphic zones were recognized (from older to younger):

Globorotalia kugleri Partial Range Zone (Late Oligocene).

Globigerinoides quadrilobatus primordius Interval Zone Early Miocene (Aquitanian).

Globigerinoides trilobus trilobus Interval Zone Early Miocene (Aquitanian-Burdgalian).

Praeorbulina transitoria Globigerinoides diminutus Interval Zone Early Miocene (Burdgalian).

The lithological and paleontological attributs indicate that the Oligocene-Miocene boundary lies between Tarjil Fn. (Late Oligocene) and Ibrahim Fn. (Early Miocene).

In this investigation microtremor recordings were conducted in three individual sites at Baghdad city. Three components of digital seismic recording system was used. The measurements were carried out in the frequency range of (1-10) Hz. Recording data were exposed to two types of analytical techniques. The first to their predominant frequencies, the second uses amplitude ratio of spectra obtained by point measurements. The results of analysis revealed that, the predominant peak frequencies in the spectral analysis are in the range of (3-5) Hz. This fluctuation may be due to local soil condition. The amplification characteristics in the form of spectral ratio for the three sites were also computed.

The increasing demand for industrial minerals and rocks for the construction industry and the need for conservation of environment in Iraq necessitate the experience of geologists about quarries so as to provide informations related to rock types, geology, chemical and physiomechanical properties and many of the problems associated with quarrying. Emphasis has been made on the scientific and accurate approches of quarrying and the importance of bench method and the effect of structure on the volumes and quantities of extracted raw materials. Suggestions concerning environmental problems and improvement of the current quarrying situation have been given

Lithological study of Oligocene carbonate exposure near Sinjar City northwestern Iraq indicates its affiliation to Palani and Tarjil Formations. One microfacies characterizes the condensed section of Palani Formation (Early Oligocene), attributed to outer shelf environment. Three microfacies were distinguished throughout Tarjil Formation, their depositional environments ranging from middle shelf to middle bathyal

zones. Sequence stratigraphic analysis delineated five sequences, four of them are of 3rd- order and one of 4th order. Two cooling events are inferred during the Middle Oligocene, corresponding to global cooling and sea-level fluctuations.

Analysis of contoured stereographic pi-diagrams for lower hemisphere equal area projections for poles to the bedding planes in the Shiranish, Sinjar/Aliji, Jaddala, Serikagni and Jeribi formations of Sinjar anticline has been carried out. The considerable discrepancy between the pi-diagrams for the Shiranish formation and the Tertiary formations indicate a Late Maastrichtian Alpine folding phase recognized in earlier work. However, the near perfect coincidence between the pi-diagrams for the Tertiary formations is discussed with respect to two possibilities for the nature and timing of folding. Firstly, that folding took place during the Tertiary in progression with deposition of the different formations. Secondly, that folding took place as paroxysmal phase of Alpine folding in the Pliocene times. Circumstantial evidence from the field supports the second possibility.