a. mahboubi

The studied section is located at the Tange-Neyzar, 115 km NE Mashhad. The upper part of the Neyzar Formation consists of shale and marl, while the basal parts of Kalat Formatiom is composed of sandstone unit with interbedded shale. An oxisol type has been identified at the boundary between these formations. There are characteristics macromorphological and micromorphological features in this oxisol unit. The occurrence of beta microfabric indicates the role of micro-organisms activities in the formation of the palaeosol. The geochemical studies indicate that the average paleotemperature is 11˚ C. The paleo-rainfall varies from 818.66 to 1563 mm (with an average 1200 mm). The pressure of CO2 was measured from 2237.10 to 2981.08, which is 7.99 to 10.65 times the current value. It corresponds to the modeled values for that geological time in the other areas of the world. In addition, the fluctuation of water-stable (falling at sea level) played a critical role in the development of palaeosol in this section.

Lower Cretaceous carbonate rocks (Taft and Abkouh formations) in the south of Yazd host lead, zinc and barite ore deposits. Diagenetic processes after deposition in these carbonates have caused the formation of these deposits. The main diagenetic processes affecting these sediments include compaction, brecciation, neomorphism, cementation, dissolution, dolomitization and replacement. The dolomitization and replacement process has led to the formation of lead, zinc and barite ore deposits. Hydrothermal fluids through the active and normal faults have provided the conditions for the formation of these deposits in the carbonate rocks of this area. The formation of the ore deposit occurred during two stages of mesogenesis and telogenesis. In the mesogenesis stage and in the burial conditions, first dolomite is formed and after the entry of hydrothermal fluids and supply of necessary elements, the replacement has created sulfide minerals. During the telogenesis stage, some parts of the formed sulfide deposits are re-exposed to meteoric fluids, leading to the formation of oxide ore deposits.

Frictional sliding may not be sufficient for the stability of a system. In almost all models in the Discrete Element Method (DEM), a local non-viscous damping is used to balance the system by applying a damping force with a magnitude proportional to the unbalanced forces to each particle. The predicted macroscopic behavior of simulated particle assembly is influenced by the damping coefficient (α). In the present research, after calibrating the DEM simulations with the results of static and cyclic triaxial tests performed on sand samples containing rounded and angular particles under confining pressure of 100 kPa and cyclic stress ratio of 0.5, to study the effect of local non-viscous damping on the static and dynamic behavior of sands, different values of damping coefficient (0.5, 0.6, 0.7, 0.8 and 0.9) were used in simulations (in three-dimensional conditions). Then, the effects of initial void ratio, confining pressure, and particle shape on the behavior of the simulated samples were determined. The simulation results of the samples under static triaxial tests indicate that the effect of local non-viscous damping on the quasi-static behavior of granular materials is not significant. Under the same conditions, the energy stored in the samples with different damping coefficients is approximately equal. Angular specimens have a higher stored energy level. α has no significant effect on the coordinate number, magnitude of contact forces, and the maximum deformation in samples at the end of the static triaxial tests (20% axial strain). Upon increasing the damping coefficient from 0.5 to 0.9, the maximum rotational and translational velocities of both groups of samples are reduced. The higher the value of α considered in the simulation of cyclic triaxial test, the greater the dissipated energy of sample; thus, its damping ratio increases. By increasing the α coefficient, the shear modulus of round and angular particles decreases. The damping coefficient does not have a significant effect on the number of contacts between particles in the samples under cyclic triaxial tests, but the magnitude of contact forces, maximum rotational and translational velocities of the particles, and maximum deformation occurred in samples decreased with damping coefficient.

The Shurijeh Formation (Upper Jurassic-Early Cretaceous) is composed of siliciclastic facies in the eastern KopetDagh basin. Moreover, the identified paleosol in this formation is calcisol type. The identified calcisols of the Ghorghoreh section have particular micro and macro morphology shapes. Since the beta microfabric is dominant in these paleosol, therefore microorganisms activity plays an important role in the formation of calcretes. The paleosols in this section have been affected by processes such as boring, micritization, cementation, and pyritization. The CO2 paleopressure has been calculated to be about 2237.1 to 2981.08, which is about 7.99 to 10.65 times more than todaychr('39')s values and seems to be similar to the modeled values for that period. In addition to biogenic activities, the water table fluctuations in the phreatic zone led to the formation of calcretic paleosols in the studied section.

Rockfill dams that are made by dumping and compacting rockfill materials are known as one of the most economical and safe dams. The main mechanical characteristics of rockfill depend on particle breakage. Particle breakage occurs when the stress levels are high enough or when the size of the particles is high enough as the rockfill particles. Particle breakage causes a change in grain size distribution of the media and causes a change in the mechanical properties of the granular media. Particle breakage is widely studied experimentally by classical laboratory tests, which need large and expensive equipment that is rarely available. Although numerical methods that are based on the continuum mechanics, such as finite element method, have been developed to be able to account for discontinuities; nevertheless, the internal discrete structure of the rockfill cannot be considered and physically modeled in this way. In addition, the fact is that these methods are not capable to simulate particle breakage to predict the mechanical properties of the rockfill materials. Discrete Element Method (DEM) can overcome these problems. In this research, discrete tri-dimensional modeling of rockfill behavior considering the particle breakage using DEM is studied. Particle breakage is modeled by a bonded particle model and, to consider particle breakage, a mechanical threshold criterion combined with a contact density of particles and a probabilistic criterion is used. PFC3D code and programming in FISH language were performed by investigating the resistance and deformation behavior. In addition, the effects of particle breakage during the tests were considered by providing a failure criterion. The model is compared with the experimental tests on Purulia rockfill dam materials, and the obtained results show good concordance with the obtained experimental results. Finally, the model and the presented failure criteria, whilst it has a simple computational procedure and high accuracy, were validated.

The Pesteliegh Formation (Lower Paleocene) is composed of 94/5 m of sandstone, shale and evaporate units in the Chahchahe section. Shale samples show that major oxides such as SiO2, Al2O3, Na2O, P2O5 and trace elements like Sr, Ba, Nb and Ce are depleted relative to Upper Continental Crust (UCC) while, U and CaO enriched. The diagram of TiO2 versus Al2O3 and Zr versus Al2O3 suggest an intermediate igneous rock as possible source rock for shale of the  Pesteliegh Formation. The diagram of K2O/Na2O versus SiO2 and ternary diagram of Th/Co/Zr, La/Th/Sc, Th/Sc/Zr show a continental arc islands as tectonic setting for this Formation. The CIA index values reveal poor to moderate degree for intensity of weathering and arid to semi-arid as paleo-climate in the studied area. In the other hand, the U/Th and Ni/Co indexes indicate oxidant condition in depositional environment. The beginning of Paleocene was along with tectonic activity and regression of sea level in most parts of the word and well the Kopet-Dagh Basin in Iran. These occurrences were most important factor for deposition of siliciclastic sediments of the Pesteliegh Formation. Due to regression, the thickness of this formation decrease, from south east toward north west in Kopet-Dagh Basin.

Ilam Formation is the reservoir rock of Maleh-Kuh oilfield located in folding-thrusting Zagros zone in Lurestan province. It is mainly composed of mud-supported lithofacies varying from mudstone to wackestone. The most important identified diagenetic processes are compaction (physical and chemical), aggrading neomorphism, different replacement (pyritization, dolomitization, glauconitization and silicification), cementation, several generations of fracture, and burial dissolution. The main recognized pore types are moldic, vuggy, stylolitic, intercrystalline, and intragranular. Paregenetic sequence interpretation of Ilam Formation indicates that a set of diagenetic processes such as syndepositional diagenesis in marine environment, as well as post-depositional shallow to deep burial diagenesis, and uplift have affected this reservoir rock. Porosity and permeability data plots show that these facies have very low reservoir quality and most diagenetic processes have not had a major effect on increasing reservoir quality, and, only in some cases, permeability has been increased by stylolitization and fracturing.

Aitamir Formation (Albian–Cenomanian) crops out in the Kopet-Dagh basin in north-east Iran.This formation is mainly composed of sandstone, shale, siltstone, and several shellbeds. One of the major components in all of the siliciclastic facies is glaucony. They are autochthonus and parautochthonus types which have formed in suitable physico-chemical conditions and replaced quartz, chert, feldspar, mica and carbonate cement. Nonselective replacement, poorly sorted, along with phosphate, fish teeth and morphological shrinkage are major evidences of autochthonus glaucony. These glauconies are pale green nascent, evolved and highly evolved. Glaucony within marine deposits (suitable host rock), associate with bioturbation, presence of pellets of nascent glaucony and debris of sparse glaucony within the matrix forms of greenhalo are others evidences of autochthonus glauconites. Characteristics of paraautochtonus glaucony, including: ooidal rims around rounded peletic glauconites, well sorted glauconys, presence of glauconites within cross lamination and low fractures in peletics glauconites due to local reworking into in early transgressive surface.

The Sachun Formation (Paleocene-Lower Eocene) is mainly composed of carbonates and evaporates that were deposited in shallow-marine evaporitic mudflat environments. The Sachun Formation in the study area has been divided into three units including: lower evaporate; middle bioclastic limestone and upper evaporate. It is mainly composed of diagenetic gypsum, which originated from dehydration of anhydrite precursor. This gypsum in the Sachun Formation generally displays alabastrine and porphyroblastic textures with corroded anhydrite relics. Petrological studies reveal that the most important diagenetic processes affected the middle Part of the Sachun Formation are dolomitization and evaporate mineralization. Four types of dolomite, ranging from early to burial diagenetic environments, were identified. These are including very fine-to-fine crystalline (D1), neomorphic dolomite (D2), fine-to-medium crystalline euhedral to subhedral dolomite (D3) and pore- and fracture-filling dolomite (D4).

The 50 meters thick Top Quartzite sediments in Kerman area is laid between siliciclastic red beds of the Dahu Formation and carbonate deposits of the Kuhbanan Formation. Three stratigraphy sections were measured at Gazuieh, Katkuieh and Dahuieh in eastern Zarand for analysis of depositional environment. Field and petrographic studies led to identification of a conglomerate petrofacies and three sandstone petrofacies (chert arenite, quartz arenite, sublitharenite) with high textural and compositional maturity. Lithofacies analysis resulted in recognition of three coarse grain (Gcm, Gms, Gt), seven medium grain (Sp, St, Sh, Sl, Sr, Sm, Se), one fine grain (Fl) and three intermediate sand-mud lithofacies (Sr(Fl), Sr/Fl, Fl(Sr)). Structural and textural evidences as well as predominant bimodal paleo-currents in most facies show that these sediments have been deposited in the tidal flat environment. The coarse, medium and fine grain sediments are deposited in tidal channels, intertidal flats, supratidal flats, respectively. We hope represented data in the study improve the basin analysis and paleogeographical reconstruction of Cambrian sedimentation.

Two stratigrphic sections from Dahu Formation (Early Cambrian), at Gezuieh and Dahuieh (type section) in E and SE Zarand, NW Kerman, with thickness of 227 and 240 meters respectively, were measured. These data have been used for interpretation of provenance of these siliciclastic sediments. Lithofacies, architectural elements and petrofacies analysis show that Dahu Formation has been deposited in meandering river system when the river was flowing from south toward the north. Provenance studies and depositional history, using petrography frameworks characteristics, paleocurrent analysis and tectonic setting (using the triangle diagram Qt-F-L and Qm-F-Lt), show that the sediments of Dahu Formation may have been derived from alkali granite related to Pan-African orogeny from Saudia Arabian train. These sediments may have been deposited as post rift sediments in Kerman region. We hope that this information can be used for paleogeographical reconstruction of the Early Cambrian time in local and regional scales.