Three stratigraphic sections were sampled to demystify the geochemical properties of the shallow marine Govanda Formation, located in the Arabia–Eurasia suture zone at ~ 1500 m above sea level. This ...study examined the geochemistry of major, trace, rare earth elements (REE) and the petrography of carbonate rocks of the lower–middle Miocene Govanda Formation. Microfacies analysis shows that packstone and wackestone dominate the ticker western section, whereas the eastern sections contain grainstone and clastic units. The carbonates were deposited in shallow marine reef-fore-reef environments unaffected by diagenetic alterations. The limestone beds have a consistent seawater-like REE pattern, slightly negative Ce anomalies (Ce/Ce* = 0.79 in massive limestone–MSL and = 0.89 in marly limestone–ML), relatively positive Eu anomalies (Eu/Eu* = 1.18 in MSL and = 1.14 in ML), and moderately high Y/Ho ratios (37.69
n
= 29). The REE + Y pattern of samples mainly retains its original characters, but the variations in the total rare earth element (ΣREE) content are detected, which could reflect minor detrital material inputs. Authigenic U, negative Ce anomalies, and trace element ratio indices such as V/Cr, U/Th, Ni/Co, and V/(V + Ni) indicate suboxic–anoxic deposition condition. A positive correlation of Al
2
O
3
% contents with Fe
2
O
3
% links the carbonate units of the Govanda Formation to marine limestones. The Rb–Sr-Ba ternary diagram, and Sr/Ba vs. Sr/Rb, Al
2
O
3
% vs. Fe
2
O
3
%, and Ce/Ce* vs. Sm/Yb bivariate analyses imply that the studied limestones originated in a passive margin tectonic setting.
The Shakha Rash granitoid occurs in the middle of Bulfat igneous complex, which is an integral part of the Zagros suture zone (ZSZ), Kurdistan region of NE Iraq. Granitoid rocks are diorite, syenite, ...monzonite, tonalite, granodiorite, and granite which are the main variants that crop out in the area and are exposed as massive and dike. These massive rocks have different textures, equigranular with deformation, but dykes show porphyritic texture and no deformation which represents two stages of injection. The granitoids are compositionally similar to I and S-type granitoid rocks that originated from continental arcs. Their enrichment in the LREE relative to HREE is high (La
N
/Yb
N
) (35.66–266.07, ave. ~ 116.76 × chondrite) reflecting positive steep fractionated patterns probably due to the occurrence of a considerable amount of felsic minerals, with positive Eu anomalies suggested cumulus plagioclase. This feature together with a relative depletion of elements Nb, Pr, Nd, Zr, Hf, and Ti but Cs, Rb, Ba, K, U, and LREE enrichment confirms the derivation of granitoids from a crustal source region in a continental arc environment. Based on trace element discrimination and Th/Yb vs. Ta/Yb ratios, granitoid rocks are formed at the active continental margin.
In Kurdistan NE of Iraq extensive beddings of well bedded carbonate rocks deposited within Tertiary- Cretaceous age. For this purpose various studies of petrographic, physical, mechanical, and ...chemical properties for building construction were carried out. Appearance of rocks was measured in the field by thickness of the beddings, joints, fractures, and brightness. The petrographic study achived under transmitted light microscope for diagenesis, weathering, allochems, and matrix. Measuring specific gravity, density, water absorption, moisture content, porosity, and saturation coefficient to qualify the rock according to its physical properties, whereas measuring compressive strength of the rocks were determined for qualifying the mechanical properties, the XRF test for determining the oxides and durability tests for qualifying their chemical properties. Eleven samples selected from Qamchuqa Formation in Binabawi anticline, Aqra-Bekhme Formation in Shakrok anticline, Shiranish Formation in Pirat anticline, Shiranish Formation in Harir anticline, Shiranish Formation in Safin anticline, Shiranish Formation in Shakrok anticline, Pila Spi Formation in Pirmam anticline, Khurmala Formation in Bina Bawi anticline, Fatha Formation in Kori syncline, Anah Formation in South Qara Chugh anticline, and Euphrates Formation in North Qara Chugh anticline. The results in terms of economic demand for building and dimension stones showed that samples of Shiranish Formation from Pirat, Safin, Harir, and Shakrok anticline are highly recommended as dimension stone and building stone, while samples of Qamchuqa, Aqra-Bekhme, Pilaspi, Khurmala, and Euphrates Formations are accepted but not recommended as dimension stone and dimension stone, samples of Fatha and Anah Formations are not accepted as dimension stone, but accepted as building stones as an insulator.
Aggregates have an important role in the development and quality of Hot Mix Asphalt pavement, Engineers prefer using different types of acidic aggregates as a dominant road pavement mixture. This ...study is focused on using a basic aggregate, for this purpose limestone is used as a replacement to sandstone and gravel in the Hot Mix Asphalt for base and binder course, due to its rough, tough, durable and stable properties, that adheres well with the binder due to its hydrophobic properties. A petrographic study and chemical analysis by XRF method was carried out for better determining the mineralogical and chemical contents. Los Angeles Abrasion test carried out for measuring abrasion of the limestone aggregates in Kurdistan Region Iraq from Cretaceous-Tertiary age in different sources of the Shiranish Formation in Pirat, Harir, and Safin, Aqra-Bekhme in Shakrok, the Pila Spi Formation in Pirmam, Khurmala Formation in Safin, the Euphrates Formation in North Qarachugh, and the Qamchuqa Formation in Bana Bawi, while the only last four formations selected for Marshal test depending on wear <45% according to Iraqi SORB, 2003 standards. The soundness test results showed that the selected four samples are within the required specifications. The aggregate-asphalt mixture molds were prepared with the optimum binder content of 4.7%, for the Marshall stability test, which revealed that all the selected four samples are suitable as a heavy-duty pavestone for the base and binder course, with BQ and Pm showed optimum stability results.
The Northern Zagros Suture Zone (NZSZ), formed as a result of the collision between Arabian and Sanandaj-Sirjan microplate, is considered as part of the Zagros orogenic belt. NZSZ is marked by two ...allochthonous thrust sheets in upward stacking order: lower and upper allochthon. The Bulfat complex is a part of the upper allochthon or “Ophiolite-bearing terrane” of Albian-Cenomenion age (97–105 Ma). Voluminous highly sheared serpentinites associated with ophiolites occur within this upper allochthon. In addition, the Gemo-Qandil Group is characterized by gabbroic to dioritic Bulfat intrusion with a crystallization age spanning from ~45 to ~ 40 Ma, as well as extensive metapelites with contact to the Walash-Naupurdam metavolcanic rocks. Due to the deformation in the Sanandaj-Sirjan Zone along the eastern side of the Iraqi segment of NZSZ, the Gemo-Qandil Group was regionally metamorphosed during late Cretaceous (~ 80 Ma). This tectono-compressional dynamics ultimately caused an oscillatory deformation against Arabian continental margin deposits as well. During these events, gabbro-diorite intrusion with high-grade contact metamorphic aureoles occurred near Bulfat. Thus, there is an overlap between regional and contact metamorphic conditions in the area. The earlier metamorphic characteristic can be seen only in places where the latter contact influence was insignificant. Generally, this can only observed at a distance of more than 2.5 km from the contact. According to petrographic details and field observations, the thermally metamorphosed metapelitic units of the metasediment have been completely assimilated, with only some streaks of biotite and relicts of initial foliation. They strongly resemble amphibolite-grade slices from the regional metamorphic rocks in the region. Metapelitic samples far from the intrusion give similar biotite cooling ages as the intrusive rocks. Thus, they may be affected by the same thermal event.
40
Ar/
39
Ar dating of biotite in metapelite rocks of Bulfat by step-wise heating with laser gave average weighted isotopic ages of 34.78 ± 0.06 Ma. This is interpreted as crystallization/recrystallization age of biotite possibly representing the time of cooling and uplift history of the Bulfat intrusion. Cooling and exhumation rates for the Bulfat gabbro-diorite rocks were estimated as ~ 400 °C/Ma and ~ 3.3 mm/year respectively. According to petrographic details, field observations and Ar/Ar dating concerning the contact metamorphism near Bulfat due to the gabbro-diorite intrusion, no significant deformation is visible during exhumation processes after the Paleogene tectono-thermal event, indicating that isotopic ages of 34.78 ± 0.06 Ma could mark the timing of termination of the island arc activity in the Ophiolite-bearing terrane (upper allochthon).
Microfacies analysis and depositional environment of Jeribe Formation (early Middle Miocene) were studied for the first time in two outcrops (Karin and Qadia villages) within the Bekhair anticline in ...the High Folded Zone, Zakho area, northwestern part of Kurdistan region-northern Iraq. In the Bekhair anticline, the Jeribe Formation overlies the Dhiban Formation and underlies the Fatha Formation with gradational and conformable boundaries. Based on field observations two informal lithostratigraphic units were identified: a thick massive dolomitic limestone unit, and a fractured limestone unit. The petrographic diagnosis of 27 thin sections show a variety of shallow marine derivative fossils with non-skeletal grains like peloids, ooids, intraclasts, and quartz grains. Relying on the detailed microfacies analysis, five major microfacies types including lime mudstone, lime wackestone, lime packstone, grainstone, and boundstone were identified and then divided into eleven sub-microfacies types according to dominant grain types. They were integrated according to their environmental differentiation into two facies associations which are: intertidal and lagoon. From the sum of field observation and facies analysis, the depositional environment of the Jeribe Formation was a shallow marine environment, deposited in the intertidal setting in the lower part and changed to a semi-restricted lagoonal environment toward the upper part.
•The Jeribe Formation in Bekhair anticline are divided into two informal litho units, which are: a thick massive dolomitic limestone unit and a fractured limestone unit.•Five major microfacies types including (lime mudstone, lime wackestone, lime packstone, grainstone, and boundstone) were recognized in the studied formation.•The depositional environment of the formation is shallow marine carbonate environment, with intertidal setting in the lower part and semi-restricted lagoonal environment in the upper part.
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