Chemical indices are widely used for characterizing the degree of weathering. In this study, we focused on evaluating the capability of chemical weathering indices to distinguish the sequence of aeolian-fluvial sediments in an arid region of Iran. Seven dominant geoforms were selected in Rafsanjan region, southeast of Iran, namely pediment, alluvial fan, margin of pediment and sand sheet, desert pavement, margin of fan and cultivated clay flat, active drainage, and margin of fan and uncultivated clay flat. One representative pedon was selected, described, and sampled for each geoform. The soil physicochemical properties of different horizons of each pedon were determined. We calculated various weathering indices, including weathering index of Parker (WIP), product index (PI), chemical index of alteration (CIA), silica-sesquioxide ratio (Kr), and CIA/WIP ratio (IR), and elucidated their depth distributions. The heterogeneity of the parent material within a given pedon was confirmed with field evidence, depth functions of clay-free sand fractions, and the uniformity value (UV) index. The horizon sequence with lithologic discontinuities (LDs) indicated that the studied pedons were formed by cyclic deposition of aeolian and fluvial sediments. The vertical variations of the weathering indices as well as the vertical trend of the Al2O3/SiO2 ratio (as a grain size index) were entirely consistent with the presence of the LDs. The results suggested that different factors, such as grain size, sedimentation cycling, and their interactive effects, should be considered in order to accurately assess the vertical trend of chemical weathering indices.

Carbonate successions are considered archives for recording the palaeoclimatic proxies and so they are suitable for understanding climatic patterns and identifying the Milankovitch cycles and cycles’s impacts on sea-level changes during Phanerozoic. In the current study, the carbonate successions of the Ilam Formation (Santonian) and their spectral gamma-ray data were chosen to identify the cycles and influencing factors on the sedimentation in one of the oilfields in the Dezful Embayment, southwest of Zagros mountains. According to available evidence, all of Milankovitch cycles contributed to changes in climatic conditions simultaneously with development of the Ilam Formation, however, the long Eccentricity cycles were dominant and have played a greater role in this issue. The sedimentation rate was estimated at 4-5.5 cm/kyr on average in the Ilam Formation. Considering the sedimentation rate and number of identified long Eccentricity cycles, it could be said the deposition in the Ilam Formation lasted in 1.13-1.8 Ma. Our results indicate that the relative sea-level changes in the studied wells correspond to the eustatic sea level. The deposition process in the Ilam Formation was largely affected by the performance of long Eccentricity cycles, eustatic sea level, and tectonic events during the Upper Cretaceous.

The most appropriate option for flood control in accordance with environmental conditions is watershed management, which has different effects on the hydrological factors, including the amount of surface runoff, sedimentation rate and the permeability in the watershed. The purpose of this study is to simulate and assess changes in surface runoff, sedimentation rate and the permeability using semi-distributed SWAT model in two periods before and after watershed management in the Anbaranchay Watershed. The results showed that the rate of sedimentation in the upstream before watershed management was 22.14 T/ha and after watershed sediment yield per hectare has decreased to 1.84T. Also, the simulation results showed that the amount of CN has changed from 75.68 to 61.24 in watershed and an increase in permeability and the flow lateral is observed. The SWAT model estimated the evapotranspiration 157.4 mm to Anbaranchay watershed. Changes in the hydrological cycle in plain sedimentary region has left the greatest impact. It seems that the SWAT model is able to simulate the hydrological cycle processes and geomorphological studies and provide valuable information.

New simplified tectonic models and depositional history of Late Cretaceous rocks are established in a part of Zagros Orogenic Belt that is located in the Northeastern Iraq. These rocks constutes the most important Cretaceous oil reservoir in the Middle East. The dependent tools are petrography, field study and the concept of drowning phases. This concept is relatively new and accurate in explanation of development of carbonate sequences growth and termination. The columns of both carbonate and clastics rocks of the area are divided into three phases of drowning: 1- Pre-drowning phase of reefal limestone which is represented by Qamchuqa Formation which is equivalent to Mauddud and Shuaba formations (Early Cretaceous) in the south Iraq and in the Gulf. 2- Transitional phase of pelagic limestone and marl deposition which is transitional to post drowning phase during which Gulneri Shale and Dokan limestone Formations (Cenomanian- Turonian) are deposited. 3- Post drowning phase of deep carbonate sedimentation during which Kometan Formation (Santonian-Campanian) and 4- Burial Phase in which Shiranish and Tanjero Formations (Maasstrichtian) are deposited by which Arabian Platform was covered by siliciclastics sediments and main carbonate sedimentation was ended during Campanian. These phases, as resulted from tectonics of Zagros, can replace the complex previously assigned tectonic and depositional history of the area during Later Cretaceous. The application of the phases revealed nearly a continuous history of deposition in foredeep during Early Cretaceous and foreland basin during later ages. This continuous sedimentation is opposite to previously cited episodic sedimentation in the Cretaceous basins. Moreover than that, the occurrences of the previously mentioned subaerial cycles of erosion (unconformities) are not ascertained. The previous cycles had segmented the rocks and history of the area into several separated and unrelated tectonic events that occurred in different basins. According to the above cycles and unconformities the tectonic setting and depositional history of the whole northwestern Iraq assumed be violent during compete time span of the Late Cretaceous by which basin isolation and uplift and erosion occurred. The above ideas are amended and the unconformable boundaries are changed to conformable ones. Consequently, in the present study, a new tectonic history and model are established for Cretaceous which agree with field observation and existed lithofacies.

Abstract: The ability of polyvinyl pyrrolidone (PVP) and bovine serum albumin (BSA) in inhibition of the crystal growth inssuspensions containing Acetaminophen as a model drug was evaluated. For this purpose sedimentation volume, resuspendability, cake formation, particle size distribution, volume surface diameter (dvs), and crystal growth after freeze-thaw cycling of the several suspensions were evaluated. ANOVA followed by Tukey test was used to determine significant differences (P<0.05). PVP in comparison with BSA showed a better crystal growth inhibition and at concentrations of 50-100 mg/100 ml inhibited crystal growth over 150 days. The combination of PVP and BSA showed an inhibition of acetaminophen crystal growth after 45 and 150 days respectively. The combination of PVP (50 mg/100 ml) and BSA (80 mg/100 ml) showed interesting results regarding sedimentation volume, resuspendability, prevention of cake formation, and crystal growth inhibition; and offer new perspectives in the preparation of suspensions.

In this research simulation model of sedimentation in dam reservoirs in the arid and semi-arid basins (Water Availability in Semi-Arid environments-SEDiments) was developed. Rainfall-runoff, erosion-sedimentation processes and sediment transfer in the river's catchment, can be simulated by WASA-SED. In this research a new module was added to the WASA-SED model. This module was developed by Fortran programming and will about a decision supporting system for reservoir desilting that supported by engineering relationships that allow the quantification of basic parameters. The model helps to evaluate the technical and economic feasibility of implementing the life cycle management approach. Validation of the model has been made using prototype data (Barasona dam in Spain). The computer simulations agree well with the prototype measurements and show that the model is a promising tool for feasibility study and economic evaluation of alternative strategies for reservoirs desilting. The results from the economic optimization routine identify the preferred sediment management technique for sustainable use of the water resource infrastructure.

Climate change is one of the most important factors influencing the hydrological cycle.The present study investigate the impact of climate change on runoff and sedimentation of the Dehbar watershed for the next 30 years using statistical model, LARS-WG and conceptual hydrological model, SWAT and WEPP. First, LARS-WG model was calibrated to generate future meteorological data in the basin. Then, the HadGEM2 model with three scenarios; RCP8.5, RCP4.5 and RCP2.6 were used to downscale meteorological data for period of 2020 to 2050. The results indicate a decrease in rainfall and an increase in temperature on the horizon of 2050. Also, the results of SWAT model show the runoff variations for RCP8.5, RCP4.5 and RCP2.6 scenarios which are -22.16%, -17.93% and -17.34%, respectively, and for sedimentation variations which are -4.4%, +9.4% and +3.2%, respectively, relative to the base period. In the WEPP model by choosing the hillslop method and using downscaled results of RCP8.5, RCP4.5 and RCP2.6 scenarios, sediment variations were estimated -6.4%, +12.6%, and +4.8%, respectively, compared to the base period.

Extensive outcrops of Eocene flysch deposits are available in the Khash area, south-east Iran. These flysches comprise sedimentary cycles of marl, shale, siltstone, and sandstone with erosional structures such as groove and flute casts. The studied sediments are deposited as a result of event-sedimentation. Diverse graphoglytids have been collected from an outcrop of these sediments, located 15 Km west of Khash. Seventeen ichnogenera have been determined among the studied deposits. Most of these trace fossils were formed in the pre-event sedimentation phase on the muddy substrates, and they include Desmograpton, Helminthorhaphe, Paleodytion, Protopaleodictyon, Scolicia, Spirophycus, Spirorhaphe, Squamodictyon, Urohelminthoida. Post-event trace fossils are low in ichnodiversity and form in the sandy or silty substrates, they consists of Halopoa, Helicodromites, Helminthopsis, Nereites, Paleomeandron, Phycosiphon, and Planolites. Some of the trace fossils such as Paleodictyon are aligned with respect to the paleocurrent directions, and were affected by the currents. It seems that fine-grained pre-event sediment surfaces was favorite for K-strategist, while post-event sediments were occupied by R-strategist trace-makers.

Shear strength is one of the critical properties of soil that affects the interaction of machine and soil. Wetting-drying cycles change the structure the soil (due to frequent surface irrigation) and affects the shear strength parameters of the soil. Therefore, the effect of this process on the shear strength parameters of coarse-textured soil (sandy loam) is studied. In this study, large soil samples were prepared and some of them were subjected to 5 wettingdrying cycle. After that, the large soil samples with/without wetting and drying cycles were compressed under three loads (0, 100 or 200 kPa) at two water contents (0.9 plastic limit; PL and 1.1PL). Then three samples were prepared for direct shear tests. The results showed that the increase in water contents will increase bulk density and cohesion, and reduce the internal friction angle. Compressing the soil after wetting and drying process resulted in an increase in bulk density and cohesion, and reduction in internal friction angle. These changes were due to clay particles mobility and sedimentation among larger particles as well as developing water films among aggregates during wetting.

The upper Dalan member in the Salman field is one of the important Permian gas reservoirs. The purpose of this study was to analyze the cyclostratigraphy of the upper Dalan member by using Evolutionary Spectral Analysis with Fast Fourier transform and multitaper methods, and thereby Milankovitch cycles would be determined and sediment accumulation rates would be estimated by Evolutionary Correlation Coefficient and Evolutionary significance levels using Acycle software and spectral gamma ray log in this field. In this study, according to the method of cycle length ratios, approximately 18 long-term eccentricity cycles and about 72 short-term eccentricity cycles and 162 long-term obliquity cycles and 342 long-term precession cycles for this section of Dalan Formation was identified. Through spectral analysis, it was revealed that sedimentation in the upper part of the Dalan Formation in the 2S-K1 well was mostly affected by astronomical control function of the long-term eccentricity cycles and short-term eccentricity cycles. In addition, the sediment accumulation rates in this well for the upper part of the Dalan Formation were estimated using Evolutionary Correlation Coefficients and Evolutionary significance levels of 4 cm per thousand years, or 40 m per million years. Based on astronomical calibration of long-term eccentricity cycles, the 7290 kyr Astronomical time scale for biozones provided by the Petroleum Industry Research Institute in the upper part of the Dalan Formation was calculated in this well. Finally, the effect of these cycles on their distribution was determined with the coincidence of 405 kyr cycles with the appearance and downfall of the presented zones.