The aim of this study is investigation of the swelling potential of the Bonab city’ s soils and created the empirical relations between physicochemical properties of the Clayey soils of Bonab with the swelling potential. The studied area is located about 130 km southwest of Tabriz in northwest of Iran. Geologically Bonab is covered by the Quaternary alluvials and recent soils which mostly is fine-grained contains different amounts of Clay Minerals where causes several events like swelling. In order to assessment of the swelling potential and characteristics of Bonab soils and establish relationships between these properties, the extensive field study especially on the agricultural fields (Bonab is the agricultural-based city), sampling and laboratory tests (classified in physical, chemical and mechanical) are conducted. For the reducing the investigation’ s errors, the 20 different location is selected and sampling is taken as representative. The results of laboratory tests are classified based on United States Department of Agriculture (USDA) classification which indicated the most of Bonab soils are Clay, Clay loam and silty Clay with the sandy Clay and salt. Also, according to the swelling potential indirect assessment, these soils are located in medium to high swellability.

Clay Minerals are considered the most important components of clastic reservoir rock evaluation studies. The Shurijeh gas reservoir Formation, represented by shaly sandstones of the Late Jurassic-Early Cretaceous age, is the main reservoir rock in the Eastern Kopet-Dagh sedimentary Basin, NE Iran. In this study, X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopic (SEM) studies, and thermal analysis including differential thermal analysis (DTA), and thermogravimetric analysis (TGA) techniques were utilized in the characterization of the Shurijeh Clay Minerals in ten representative samples. The XRF studies showed that silica and aluminum oxides are present quantities. The XRD test was then used to determine the mineralogical composition of bulk components, as well as the Clay fraction. The XRD patterns indicated the presence of dominant amount of quartz and plagioclase, with moderate to minor amounts of alkali feldspar, anhydrite, carbonates (calcite and dolomite), hematite and Clay Minerals. The most common Clays in the Shurijeh Formation were illite, chlorite, and kaolinite. However, in very few samples, glauconite, smectite, and mixed layer Clay Minerals of both illite-smectite and chlorite-smectite types were also recognized. The XRD results were quantified, using the elemental information from the XRF test, showing that each Shurijeh exhibited low to moderate amounts of Clay Minerals, typically up to 21%. The amount of illite, the most dominant Clay mineral, reached maximum of 13.5%, while the other Clay types were significantly smaller. Based on the use of SEM and thermal data, the results of the identification of Clay Minerals, corresponded with the powder X-ray diffraction analysis, which can be taken into account as an evidence of the effectiveness of the thermal analysis technique in Clay typing, as a complementary method besides the XRD.

The presence of Clay Minerals of any type, amount or distribution pattern in hydrocarbon wells causes numerous problems in the formation evaluation. In this research, 15 core samples from Asmari Formation in the Maroun Oilfield were selected in order to study the type and distribution pattern of Clay Minerals by laboratory investigations. The XRD and microscopic results showed the studied samples consisted mainly of quartz (14. 7-72. 2%) and carbonate Minerals (3. 0-65. 4%) as main constituent phases,while the plagioclase (0. 0-6. 7%) and Clay Minerals (3. 3–, 44. 5%) were identified as the main accessory Minerals. In some samples, sulfide and ferrous Minerals (0. 0-2%) were also identified. The calculated percentage of illite in mixed-layer smectite/illite showed the diagenesis has occurred at different depths of reservoir. The SEM/EDX analysis performed on various types of Clay Minerals showed that kaolinite size varied from 0. 7 to 6. 5 μ, m in studied samples. In addition, Illite size ranged in our studied samples from 0. 4 to 3. 6 μ, m. Our results indicate that the Clays in the Asmari Formation occur in three main patterns as dispersed, pore-bridging and pore-filling with the variation of the total amount of Clay Minerals, min 3. 3% and max 44. 5% across the length of Asmari Formation.

Clay mineralogy of paleosols provides more information about Quaternary climatic changes and paleoenvironmental conditions. Clay Minerals of an alluvial fan in eastern Isfahan were studied, using x-ray diffraction analysis. Studied paleosols are located on old Qf1 and Qf2 geomorphic surfaces. Qf1 geomorphic surface is older and topographically higher than Qf2. The results of Clay mineralogy show dominance of palygorskite and smectite in calcic (Bk) and argillic (Bt) horizons of Qf1 geomorphic surface, respectively. Calcrete (Bkm) in the paleosol of the Qf1 surface was formed in the semi-arid paleoclimate. It seems that during more humid periods, carbonates enhancement and porosity decreases in calcrete (Bkm) horizon have caused increase in ionic activity and formation of pedogenic smectites in this horizon. In the next drier periods, the calcrete (Bkm) horizon was enriched in palygorskite via translocation and autogenic formation. The palygorskite fibers in calcrete (Bkm) have been protected by calcite crystals. The comparison of the argillic horizons of Qf1and Qf2 geomorphic surfaces indicates dominance of smectite in Qf1 argillic (Bt) horizon and palygorskite in Qf2 argillic-calcic (Btk) horizon. Regarding to Uniformity of parent material and landform, this difference is due to high weathering in the argillic (Bt) horizon of Qf1 and protection of palygorskite in the argillic-calcic (Btk) horizons in the soil of Qf2 surface. It is recommended to use Clay mineralogy of calcic horizons, argillic horizons and calcretes as a powerful tool in geomorphology investigations.

Loess/soil sequences have been proven to be excellent paleoclimate indicators. Large areas of northern Iran are covered by loess deposits which provide a good condition to carry out research on paleoclimate, paleosols and discontinuities. The objectives of this research were to identify Clay Minerals of soil-loess sequences, to determine the role of climate change in Clay mineral transformation and to estimate the relative ages of soil development based on archaeological information. Samples were analyzed by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The results showed that kaolinite, illite, quarts and feldspar were dominant in the fine Clay, coarse Clay and silt fractions. The type and the quantity of Clay Minerals in soils are highly correlated with parent material. Semiquantitative estimation indicated that different Clay Minerals are quantitatively different in the profiles. This may be due to different weathering rates caused by cool/dry and wet/warm periods. A high degree of chlorite to smectite transformation was observed in deep soil horizon (130–170 cm) where a developed horizon was buried. Differences between soil layers development were confirmed by comparison of oxalate and dithionite extractable Fe.

Transformation and neoformation of Clay Minerals as affected by various physiographic positions were studied in soils from semi-arid regions of Fars province in southern Iran. Soil samples were taken from control sections of soil profiles at various physiographic units. Clay specimens were prepared from soil samples. The Clay mineralogy of specimens was analyzed by X-ray diffraction. Mica (illite), chlorite, smectite (montmorillonite), vermiculite, palygorskite, and interstratified illite-smectite and chlorite-smectite were recognized. The higher physiographic units contained more illite and chlorite, whereas the lower ones had a higher montmorillonite and palygorskite. This was further confirmed by changes in cation exchange capacity of soils. Inherited illite and chlorite were transformed to montmorillonite and vermiculite. It is possible that neoformation of montmorillonite and palygorskite from soil solutions has also occurred.

Lake Urmia is the greatest hayper salin Lake in the world. This Lake, located in Azerbaijan area, Northwest of Iran is an intra-continental sedimentary basin. Its area is about 6000 km2 with an average water depth of 6 meter. Evaluation of past climate change in Lake Urmia, according to Clay Minerals, is the main subject for current study. For mineralogical and sedimentological investigations 18 sediment cores were collected from the east and west of Urmia lake. 96 samples from 18 sediment cores in transect to the center of lake were collected and studied by X-ray diffraction (XRD) technique. The Clay Minerals include Kaolinite, Illite and Montmorillonite. Kaolinite and Illite are the most important Clay Minerals in the Coastal plain of urmia lake. Origins of Clay Minerals in the Coastal plain of urmia lake are generally detrital, occurred by physical weathering and indicate composition of bed rock. The study of surface sediments indicates that amount of Clay Minerals from margin to center of the lake such as another detrital mineral (Quartz) is decreased. In addition, amount of them towards depth is increased. Therefore, it shows the presence of a high water level and cold-humid climate in the past (late Pleistocene).