جستجوی مقالات مرتبط با کلیدواژه « sedimentary facies » در نشریات گروه « زمین شناسی »

To prepare sedimentological data, 98 surface sampling stations have been designed from the seabed in the continental shelf in the southern part of the Caspian Sea and along the coast of Iran. Indicators such as the type and amount of sediment load transported to the sedimentation environment, the energy of waves and sea currents, as well as how the slope of the seabed changes, play a role in the production and diversity of the sedimentary facies. 9 sedimentary facies are the most abundant in the surface deposits of this area and on average, in the sediments of the continental shelf, there are 1% by weight of coarse-grained particles, 25% by weight of medium-grained particles and 74% by weight of fine-grained particles. The composition of sedimentary facies in this area is controlled by indicators such as the size of sedimentary particles, the amount of sedimentary load carried to the environment, the energy of waves and sea currents, and how the slope of the seabed changes. In the marine environment of the study area, sub-sedimentary environments, Backshore, Foreshore, Shoreface, Offshore transition zone and offshore can be identified. The two facies of slightly gravelly Mud and Mud are more abundant than other facies.

The carbonate interval of the Asmari formation along with sandstone deposits were deposited in most areas of the Zagros sedimentary Basin, including the Ahvaz area, in Oligo-Miocene. In this study, the effects of depositional and post-depositional environments on the reservoir quality of zone A7 of the Asmari Formation in well No. 4 in Ahvaz oil field were studied. The study of the sequences of the Asmari Formation in this section led to the identification of 11 carbonate facies, one evaporite facies, one mixed carbonate-siliciclastic facies, and one siliciclastic facies. Sedimentary environments of tidal zone, lagoon, coral reef and open sea were introduced for the depositional environment of identified facies. Due to the absence of sudden changes, it seems that the studied deposits were deposited in a ramp-type carbonate platform that was influenced by siliciclastic sediments from the Zagros river systems. The immature sedimentary texture of the sandstone facies indicates the proximity of the origin of the quartz sources to the carbonate basin. Among the diagenetic processes that have affected the examined sequences, the following processes can be mentioned: micritization, cementation, neomorphism, physical and chemical compaction, dissolution, fracture development and filling, dolomitization, and anhydritization. These diagenetic processes occurred in post-depositional marine, meteoric and burial diagenetic environments. Many fractures were filled with petroleum, which indicates that fractures, along with dolomitization, chemical compaction, and fenestral pores, are among the most important post-sedimentation complications to increase reservoir quality. While cementation and anhydritization resulted in reducing the reservoir quality by closing the pore spaces .

Calcareous springs of Ab-e Ask are located 85 km northeast of Tehran, in the southern range of the Damavand volcano. Microscopic studies represent the existence of four abiotic and two microbialite facies in the Ab-e Ask travertines. The travertines are the main deposit types of these springs. Based on sedimentation sequence and lithofacies these travertines are categorized as first type (vent and channel), second type (pound, dam, and cascade), and third type (laminated) travertines. On a δ18O versus δ13C plot (VPDB), these travertines are plotted in the oncoid and crystalline crust lithofacies fields. These facies show the character of hydrothermal spring and set the spring in the thermogenic group. Positive values of the Langelier Saturation Index (LSI) for Pashnak, Nadaali, and Zagh springs indicate that these water samples are supersaturated with respect to calcium carbonate, which leads to considerable sedimentation around the springs. In contrast, a negative LSI value at the Sare Pole spring indicates the water is undersaturated with respect to calcium carbonate. Therefore, this spring has a lesser role in travertine deposition compared to the other springs. Also, the position of the samples on the modified Gibbs and Van Wirdum diagrams, suggests that the interaction of water with carbonate and to some extent silicate rocks is considered as the most important source of Ca and Na.

The sediment cores BAG, AZD and AM in the Babolsar, Jouybar and Zaghmarz areas are located at the southern Iranian part of the coastal plain of the Caspian Sea. These areas are contained by major mountain ridge, the Alborz in the south (Central Alborz Structural Zone). The Alborz Mountain represent the main source of terrigenous materials in the South basin of the Caspian Sea. The geology of the southern part of the Caspian Sea catchment include sedimentary deposits, loess and terrasses, volcanic rocks, Precambrian metamorphics and Jurassic massive limestones (Aghanabati 2004; Lahijani and Tavakoli 2012).Sedimentary facies are controlled by physical processes such as velocity, depth and type of flow and sediment transport rates (Catuneanu 2006). Sediments are deposited in various depositional environments based on physical, chemical, and biological processes (Fursich, 1995; Walker, 2006). This study focuses on the interpretation of sedimentary facies, sedimentary environment and geochemistry of the sediments from the core successions. The results of this study can be useful in the palaeoenvironmental reconstruction in the southern Iranian part of the coastal plain of the Caspian Sea through the Quaternary time.

Detailed field investigations were carried out on the three core sediments from the Babolsar, Jouybar and Zaghmarz areas. Using the rotary drilling machine, cores BAG, AZD and AM were obtained during 2016 fieldworks. A total of 88 representative samples were collected from three cores at different depths for the sedimentological (46 samples) and whole rock geochemical (42 samples) analyses. After collection, selected samples were sealed in polyethylene bags and then air-dried in the laboratory. The granulometric characteristics and textural properties were determined using Sieve analysis. Then, 46 samples were classified following Folk’s (1974). Subsequently, the 42 samples were powdered to less than 200 mesh using an agate mortar. The selected major and trace elements concentrations were measured using an Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) at the Geological Survey and Mineral Exploration, Tehran, Iran.

Based on the sedimentological characteristics, cores BAG, AZD and AM have been divided into three lithofacies. They include sandy mud, muddy and sandy to silty sand lithofacies. Sandy mud lithofacies is characterized by pale-yellow to light-brown (partly mottled), poor sorting with a maximum thickness. This facies is also dominated by massive to rarely thin lamination, abundant plant fragments and roots, individual shell fragments, and lack of marine fossils. The presence of plant roots and pale-yellow to light-brown colour and massive to thin lamination claystone facies indicate suspension fallout from standing water in floodplain setting (Selim 2017).Sandy/ silty sand lithofacies is supported by the presence of unconsolidated lightly gray silty sand, moderate to well sorting, with high bivalve contents and the deposition of alternating layers of silt and fine to coarse sand. This lithofacies has an unclear and irregular boundary with the underlying facies and has up to 1 m thickness. Coarse-grained texture with moderate to well sorted particles indicate deposition under high-energy conditions in a beach setting (Sim and Lee, 2006)Muddy facies consists of poorly sorted, alternative horizons of light green to dark grey-coloured silty clay, with the thickness varies from 0.5 to 2 m. In this lithofacies, foraminifera and ostracod shells, endogenic gypsum mineral as well as calcite were also observed. The fine-grained texture, dark gray to black colored and the presence of foraminifer and ostracod shells indicates deposition may have taken place under low-energy environment in a relatively reduced oxygen contents lagoon (Geel, 2000; Corda and Brandano, 2003; Amao et al., 2016)The behaviour of Ti/Al, Fe/Al, Zr/Al and Si/Al can be exploited to acquire information on grain size (Dypvik and Harris, 2001). In the studied cores, Ti/Al and Fe/Al, and Zr/Al and Si/Al ratios show well correlations in the fine- and coarse grained horizons, which is matched by the muddy and sandy to sandy mud facies, respectively.In finer-grained sediments, Rb/Zr can be used as a proxy for changes in grain size, with lower values representing fine-grained material and higher values representing coarse-grained material. Increases in Zr/Rb proxy is matched by an increase in the coarse fraction in the sandy and sandy mud facies, as evidenced by the grain size analysis. A decrease in the Zr/Rb ratio is matched by an increase in clay fractions, in the muddy facies.

 The sediment cores BAG, AZD and AM in the southern Iranian part of the coastal plain of the Caspian Sea, are dominated by mud and sand fractions. These sediment cores represent the Sandy mud, Sandy/silty sand and Muddy lithofacies. These lithofacies were deposited in the flood plain, beach and lagoon environments, respectively. The geochemical behaviour of most elements, in a general way, is related to the grain size in the sediments. Samples with high Si/Al and Zr/Al ratios are generally coarser grained, while high Ti/Al, Fe/Al and Rb/Zr are related to fine-grained samples.

Lower Cretaceous deposits are outcropped in the Markesh Mountain, 15 km north of Ravar (Kerman Province), with a thickness of 143 m, and this section includes intercalation of gypsiferous marls, thin-bedded limestones, thin- to medium-bedded limestones, and medium- to thick-bedded limestones. For the shale and gypsiferous marls in the base of stratigraphic column due to the absence of fossils and also based on previous geological studies, the Upper Jurassic age has been considered. In the studied succession, 14 genera and 17 species of foraminifera, three genera and four species of calcareous algae, as well as 16 genera and 24 species of ostracods were identified, and the Barremian to Albian age was determined. The upward section, the Lower Cretaceous succession at the Markesh Mountain are covered by Neogene deposits. In general, the studied deposits include evaporitic facies and two marl and calcareous facies. The calcareous facies based on the microfacies characteristic consist of three sub-facies, (A) corresponding to the coastal sub-environment above the tidal zone, (B) the lagoonand (C) the bar sub-environment. Based on studies, Lower Cretaceous succession at the Markesh Mountain section was deposited in a shallow carbonate platform.

Reconstruction of past climate change can provide us valuable information about the time, scale, and details of climate changes. For reconstruction of late quaternary climatic conditions, various methods are used, as well as the use of losses, paleomagnetism, paleontology, etc.One of these methods is to use stable isotopes of carbon and oxygen, which is particularly valuable information on the temperature of the depositional environment, digenesis temperature, the temperature changes in different digenesis environments, separating different areas carbonates offers Considering the importance of Gorgan Bay from different aspects and the fact that not many studies have been done in this region regarding long-term climate change, in this research we have tried to use different data obtained from sedimentary cores harvested from the southeastern part. Caspian Sea (Gorgan Bay) Temperature changes and environmental conditions of the region in the late Quaternary to be studied and reconstructed. Gorgan Bay with an area of more than 400 km is located in the southeastern part of the Caspian Sea (36°48’N, 53°35’E and 36°55’N, 54°03’E, 60 km ×12 km, maximum depth of 4 m ). Gorgan Bay formed during the Holocene period by a sandy spit which is named Miankaleh coastal barrier system. It is connected to the Caspian Sea through the inlet of Ashoradeh-Bandar Torkaman (Chapaghli) which is located in the northeastern part of the Bay This bay is mainly influenced by processes that are operating within the basin. Water balance in the Gorgan Bay is influenced by freshwater inflow from a number of small rivers and streams, including Gorgan-roud from the north and QarehSu from the east. These two rivers drain runoffs from residential and agricultural areas into the bay.

In this for reconstruction of late Quaternary climatic conditions a sedimentary core (N1) were collected from Gorgan Bay using a gravity corer. The core was first examined for magnetic susceptibility (MS). After slicing the core and subsampling with certain distances, Laser particle size analyzer used (Horbia LA-950) for grain size analysis. Also to specify total organic matter content (TOM), loss of ignition method (L.O.I) was used. For this purposes, a portion of each sample (about 3 gr) was placed inside a crucible and heated at 550 ° C for 5 hours and after that the weighing percentage of the organic material was reported. For measurement of carbonate content (CaCO3%), coarser grain particles were manually removed and remaining sediments were placed in a muffle furnace (Excitation, EX.1200-12L) for 1 hour at 950 °C . For 14C dating, totally 3 organic matter samples were sent to the Poznan Laboratory, Poland, The oxygen and carbon stable isotope analysis was carried out on the non-digenetic and negligible digenetic benthic foraminifera (Ammonia Beccari) by mass spectrometer in the Winsor Laboratory, Canada. Paleotempreture of the seawater estimated based on δ18O values for seawater and its counterpart in aragonite.

Grain size, was very variable from sand to clay. N1 core consists of 39 sandy silt facies, 28 silty facies, 9 silty sand facies, 9 facies of gravelly sandy mud , 3 facies gravelly muddy sand and 1 facies gravelly sand. The maximum and minimum ​​of sand were abstained at 617 and 690 cm (80.27% and 0%), respectively, while the highest content of silt and clay were at depth 138 and 416 cm (99.45% and 8.95%), respectively. The lowest amount of silt content was observed at 626 cm (7.23%). The average of sand, silt and clay in this core was 25.13%, 72.52% and 1.56%, respectively. Result of magnetic susceptibility showed a close relationship between particle size distribution and MS magnitude due to variation in terrestrial influx, which is caused by sea-level fluctuations in different times. This process increases with particle size and ranges of MS simultaneously with sea level fall and decreases during sea-level rise. The range of oxygen (δ18O) and carbon isotope (δ13C) was between -4.22 to -1.17‰ and 2.66 to‏ -0.94‰ with a mean of 3.34 and -2.11 ‰ correspondingly. According to the results of carbon dating (14C Dating), age of sediment in the N1 achieved 22070 cal. The rate of sedimentation in the cores varied from 0.57 to 3 mm. Reconstruction of paleotemperature with stable isotopes showed that the maximum temperature recorded in the core was acquired at 144 and 686 cm (27.4 and 27.1°C) and the minimum temperature was 450 cm (13.7°C). The mean temperature in this core was 22.2°C.

1-Caspian sea sediments as one of the best region in the world ,record Quaternary climate change in northern IRAN. 2- Accordingly, seven warm and cold periods were identified, which the coldest period being the last glacial maximum (Wurm) with a temperature of 13.7 °C. Furthermore, the highest temperatures related to the pre-glacial and the present periods (about 27°C). Moreover the sedimentology and magnetic susceptibility data confirmed the above results. 3-The degree of magnetic susceptibility in different core subsamples indicates environment conditions and low sediment rate. 4 - The rate of sedimentation in the cores varied from 0.57 to 3 mm. 5 - Reconstruction of paleotemperature with stable isotopes showed that the maximum temperature recorded in the core was acquired at 144 and 686 cm (27.4 and 27.1°C) and the minimum temperature was 450 cm (13.7°C). The mean temperature in this core was 22.2°C. 6 - Based on the results of 14C age and stable isotopes 15 centigrade changes in temperature have occurred during about 22,000 years.

The sequence stratigraphic studies provide information regarding the distribution of different facies within sedimentary basins. With determining relationship between reservoir or non-reservoir facies and sequence stratigraphy, dissemination of reservoir zones can be achieved within sequence stratigraphic framework. In this paper, using petrographic studies correlated with Gamma-Ray deviation logs, the sedimentary environment, sequences and systems tracts of the Oligo-Miocene Asmari Formation were revealed in one of the Iranian oil fields. Moreover, based on the wireline logs and petrophysical analyses, the factors controlling reservoir quality including porosity, water saturation and shale volume were invistigated within sequences and their systems tracts. The study showed that in general, the highstand systems tracts have higher reservoir quality than the trangressive systems tracts. Distribution of grain-suported and nearshore facies and also absence of anhydrite facies in the upper parts of transgressive systems tracts and the lower parts of highstand systems tracts resulted in development of the best reservoir quality zones within each sequence. This type of studies is very helpful in analysing the sedimentary basins and discovering distribution of the hydrocarbon reserves, and thus it could assist in management of risk reduction in exploration and development activities.

The Upper Red Formation (URF), with the age of Miocene, is mainly composed of clastic sediment including interbedded marl, sandstones and slightly conglomerate layers as well as some evaporate layers mostly in lower parts of the formation. The lithology, color and thickness of this formation are variable in a different locality (Aghanabati, 2004). This formation is the only cap rock for the Qum Formation in the Central Iran zone especially into the Sarajeh and Alborz gas-fields (e.g., Morley et al., 2008). The URF has significant distribution in the northwestern of Iran and hosts significant Cu and Pb-Zn deposits (e.g.; Sadati et al., 2016). The constituents of this formation, particularly in the sandstone layers, provide valuable information in relation to the sedimentary environment and the geodynamic location of this formation (Rieser et al., 2005). In this research, based on the facies analysis (Miall, 1996, 2000), modal analysis and geochemical data, sedimentary environment and tectonic setting of these clastic layers in the Chehrabad deposit section, northwest of Zanjan, are interpreted.

This research is based on a detailed study of lithology, sedimentology and geochemical data of the URF. During field observations, the thickness of sandstone layers and their colors were clearly defined. In order to interpret the sedimentary environments of this formation, a detailed lithofacies have been analyzed during this study. Lateral and vertical variations in all layers have been considered. About 23 thin sections from collected samples are studied by polarizing microscope at the University of Zanjan. In each thin section, the 250-points, based on the Gazzi-Dickinson method, were counted. To investigate the tectonic setting of these sandstones, 9 samples with the least amount of weathering and calcium carbonate were selected for geochemical analyses by XRF methods.

Chehrabad area is located in the northeast of Mahneshan, approximately 75 km, northwest of Zanjan. Rock units exposed in this area belong to the Lower Red, Qom and Upper Red formations. The thickness of the URF in this area is about 980 m and consists mainly of three main units. These units, from bottom to top, consist of evaporate layers, alternation of mudstone and grey to red sandstone and finally mudstone with interbedded gypsum layers with a thickness of 235, 590, and 155 m respectively. The studied sequence is a part of the middle portion of the URF, with 231 m thickness and has the highest amounts of sandstone layers. Based on the field observation, the middle parts of the formation including 7 gray to red color sandstone, which is alternate with the red mudstones. The sandstones in the Chehrabad area are grey to red and have poor imbrication. According to the sorting and roundness parameters of the grains and also the low amounts of clay matrix (less than 5%), these sandstones are perhaps to be mature in terms of texture maturity. Based on the types of sandstone grains and the Folk (1980) classification, the URF sandstones in the study area is classified as feldspathic litharenite to litharenite. Facies analyses, the color of layers, presence of cross-bedding and plant fragments, lack of gravel grains, all represent an oxidized continental environment, such as a fluvial system with a highly sinuous channel (meandering river). Also, the presence of symmetric ripple marks and marine trace fossils indicate that the sedimentation of some parts of this formation has taken place to a tidal condition and most likely close to the coastal environment. In addition, based on field studies and facies analysis, identified lithofacies in Chehrabad area include Fl, Sm, Sh, Sr, Sp, St and Fm. According to the characteristics of each facies and based on the method of Miall (1996), these sandstones were deposited in fluvial and tidal depositional systems. The results of petrography and geochemical studies have been used to interpret the tectonic setting of sandstones in the middle parts of the URF. Based on triangular diagrams of Dickinson and Suczek (1979) (Qt-F-L) and Ingersoll and Suczek (1979) (Qp-Lvm-Lsm and Lv-Lm-Ls), also using binary variables graphs of Bhatia (1983) and Roser and Korsch (1986), the tectonic setting of these sandstones is active continental margins and probably foreland basin.

The URF in the Chehrabad area consists of 3 parts and the thickness of the middle part of this formation is about 231 m, with 7 sandstone layers, which alternation with red mudstone beds. Based on microscopic studies, these sandstones are classified as feldspathic litharenite to litharenite. Based on field evidence and the presence of cross-bedding, plant fragments, lack of gravel grains, symmetric ripple marks, presence of trace fossils and also the type of facies, seven lithofacies (including Fl, Sm, Sh, Sr, Sp, St, and Fm) are recognized. The data obtained from point-count and geochemical studies clearly show that the tectonic setting of these sandstones in the Chehrabad area is an active continental margin.

This study tries to evaluate the geological properties of a travertine spring and its related deposits. The identification of sedimentary facies of springs could be applied as a method to distinguish the type of travertine springs. Therefore in this study, that method has been used for the determination of the type of the spring. Results obtained from facies analysis reveal 13 sedimentary facies that could be categorized into two groups including organic facies which contain five facies and abiotic facies containing eight facies. These facies show the character of hydrothermal spring and set the spring in the thermogenic group. The chemical composition analysis of the spring water represents the facies of NaCl, Na-Ca-SO4-Cl can be considered to be precise chemical facies. The presence of calcium and sulfate as the second most frequent ions, after sodium and chloride, may initially indicates the existence of gypsum or anhydrite deposits in this area. On the other hand, given the absence of sulfate-bearing sediments in this region, it can be concluded that the interaction of water and magmatic systems was the most important source of sulfate in the spring water. Based on the rock mechanical properties of the travertine, it was revealed that with increasing age of the sediments their consolidation degree increases. The hardness of sediments shows an increasing trend by increasing distance from the spring vent.

Geomechanical studies have important applications in various topics such as wellbore stability, well completion, well orientation, hydraulic fracturing plans and operations, sand production and hydrocarbon fields subsidence. It is necessary to prepare earth mechanical model of the well in the field. In addition, one of the necessary subjects to prepare mechanical earth model (MEM) is providing continuous rock mechanical parameters in the well. Rock mechanical parameters change by any variation in lithology. In this study, rock mechanical parameters are provided in continuous form, for Faraghan, Zakeen and Sarchahan formations for a field in the Persian Gulf and these parameters are clustered. Clustering resulted in recognizing six clusters with various rock mechanical characteristics. Petrographic study (i.e. determining facies, cementation and diagenesis) recognized five facies with different petrographic and cementation characteristics. These facies include quartz arenite and arkosic sandstones, shales, red mudstone and carbonates. A correlation between sedimentary and geomechanical facies was found. According to petrographic and geomechanical studies, the studied interval was divided into 7 sections. Accordingly, variation of rock mechanical parameters with regard to change in lithology was investigated. In addition, the impact of rock composition, cementation and compaction changes on rock mechanical parameters were evaluated as well.

Sedimentary environments are the best place to keep records of past events and evidence of fundamental events occurring on the surface of the earth within sedimentary units and their discontinuities. The identification and separation of these sedimentary units have often been the goal of many geological projects with different scientific and practical objectives. Detection of the alluvial deposit has always been of high importance when combined with their study. These hybrid studies are usually carried out in direct (sampling) and indirect methods (geophysical methods). In previous studies, in almost all researches, the necessity of carrying out sedimentology studies to better interpret the identified sequences and their adaptation to GPR studies has been emphasized by the researchers. This combination of studies, in addition to separating different units in terms of grain size, may include other factors such as the presence the quality and depth of fluid (ground water and water table), uniformity of particle size (sorting), particle size, and sedimentary structures. The main objective of this research is to identify sediments and ambient environments of alluvial soils by integrating the data from sedimentation from wells and GPR. The study area is located in Guilan province, between Kouchesfahan and Lasht-e-Nesha cities in the coastal plain of the Caspian Sea. The climate of the study area is humid and the annual rainfall is an average of 800 mm. From geomorphology point of view, the northern boundary of the Alborz is in accordance with the cluster of tertiary deposits and the coastal plain of the Caspian Sea. Under the sea terraces and alluvial plain covers, there are the Miocene-Pliocene-Quaternary marine rocks that have been displaced by the retreat of the Caspian Sea.

Firstly, GPR data (using 100 megahertz antenna, MALA) was taken to 11 km long land along the Kouchesfahan road to the Lasht-e-Nesha. Then, according to the radar profiles, they were drilling 7 sedimentary boreholes for media depth 2.7m to combine with sedimentology data. Global Positioning System is used to determine the location. the resulting data for the processing stages entered the Reflex-W software. After performing the necessary processing considering the radar facies and the depth of penetration of the waves in the radar profiles, suitable points for drilling boreholes were selected for a sampling of subsurface sediments (7 stations). The average depth of the drilled boreholes is 7.2 m. 42 Sediment samples were taken in each well based on the visible changes, including sediment type, grain size, color, moisture, and organic matter content. In the laboratory, grading experiments were carried out after the preparation of the samples (drying and separating organic matter), direct measurement of the dimensions with morphoscopy, dry sieving, and hydrometric method. In addition to the initial analysis of grain size, other statistical parameters such as the average of diameter, mean, sorting, skewness were measured.

Investigations have led to the identification of five radar facies (Reflectors no-continuous undulating with concave-convex pattern, Reflectors continuous with concave-convex pattern, Reflectors no-continuous with different angle, Reflectors no-continuous parallel with low angle, Reflectors no-continuous with low angle and attenuation high and nine sedimentary facies; silty very fine Sand (Zs), fine Sand (s), sandy Gravel (sG), gravely fine Sand (gS), organic matter (O), silty coarse Sand (zs), coarse Sand(S), muddy slightly gravelly sand (g)Ms, which represent different parts of the river environment, including the river canal and floodplain. In this region, the amount of fine-grained particles and organic matter increases from the south to the north. The facies are likely to be part of the old channel of the Sefidrud River when the channel has been redirected to the east. Changes in the percentage of grain size in the boreholes have irregular variations, which the number of fine grain particles is increased from the upstream to downstream of the region. Grains tend to be coarser from the bottom to the top of the boreholes and finer toward the shore. Sorting are bad and very bad in most samples, which indicates the deposition of finer grain particles among coarse grains. From the upstream side, in most drilled boreholes, sediments show a finning and a coarsening upward sequence that indicates the energy fluctuations of the environment over time.

The results of this study showed that wet, fine-grained with high organic matter content environments cause the destruction of the wave and including the radar method's limitations. Also, in urban environments and through the passageways, vehicle overpasses and power rails affect radar profiles and cause the radar profile to be illegible. In the studied area, the depth of effective influence of the waves is not more than 3 meters. In this research, based on valid scientific classification, 5 radar facies and 9 sedimentary facies related to different sedimentary environments were identified. The results showed that radial facies, with respect to depth, particle size, moisture, organic matter and evaporates content limitations, can be very good for identification of various sediments, especially at low and near depths. By performing this research and matching the sedimentary and radial facies, the ability of the two methods in another interpretation was also identified and such adaptations can be applied in other areas with great confidence.

In this study, in order to investigate the effect of the physical and chemical properties of carbonate rocks on the development of karst forms, carbonate rock units of the Sarvak Formation have been studied in the anticline of the Rag- Henna (south of Isfahan). This formation consists of a thick sequence of carbonate deposits, and karst geomorphological phenomena such as carneys, dissolution cavities, ponors and karst springs are well visible. The Sarvak Formation is composed of 8 sedimentary that are deposited in tidal, lagoon, barrier and open sea environments. According to the results of chemical analysis, the percentage of calcium oxide in the studied samples is more than 40% and monirim oxide is at most 1.27%. Also, by conducting geotechnical experiments, the porosity of carbonate samples was determined. Diagenic processes affecting the porosity of the Sarvak Formation in the region include compression, cementation, dissolution, fracture and dolomitization. The lacquer supporting luminosities of the lagoon division have better porosity due to the effect of their dissolution and fracture, and more variation in the karst forms of this microfacies is observed. Therefore, determination of porosity and the evaluation of diagenesis processes on carbonate rocks can be a useful tool for separating the zones from the point of view of their ability to develop.

Introduction ;In the most gravel bed rivers, particle size exponentially decreases to the downstream. The study of particle size fining trend to the downstream and determination of the effective processes on it along the recent rivers is accomplished in the different parts of Iran. The river sedimentary facies are deposited in the channel and overbank areas and they are provided important information about sedimentary environment and deposition rate, the extent and development of the river channel and floodplain. These sedimentary facies that are deposited in the different depositional conditions have been achieved from variations of flow regime and/ or variation in the depositional environment in the large scale. The aim of this study is to investigate of the particle size variations and the effective controllers of fining trend to downstream, to determine of the important factors in creating sedimentary discontinuities and to study of the sedimentary facies, architectural elements, determination of depositional model and some paleohydraulic parameters of river. The Mulid River catchment with elongated shape is located in 120 km of southeast Qayen in the Southern Khorasan Province, in the 33̊ 24ʹ 44.3ʺ to 33̊ 35ʹ 11.4ʺ east latitude and 59̊ 56ʹ 42.5ʺ to 59̊ 58ʹ 44ʺ north longitude. According to the geological classification of Iran, this basin is a part of the East Iran flysch and mélange belt that is located in the east of the Lut Block.
In order to sedimentological studies, 30 sediment samples unsystematically were collected from upstream to downstream and from about 20 cm depth of the main channel bottom of river (with 30 km long). The granulometry analysis of the studied samples were achieved using the dry sieving method with 0.5 φ intervals and weight percent of gravel, sand and mud size particles were estimated. The sediment naming is done using Folk (1980) classification and the estimation of sorting, skewness and kurtosis parameters, after drawing related graphs, are achieved based on the inclusive graphic method of Folk (1980). The determination of sedimentary facies and architectural elements in the studied river channel wall and using codes for them were based the Miall (1996, 2006) classification. In this study, to reconstruct the paleodischarge rate, the paleochannel dimensions and sedimentary characteristics have been used and the presence of empirical equations have been used to estimate of paleohydraulic parameters.
Discussion of Results and The sedimentological studies along the channel in this river catchment are shown that the trends of particle size variations completely does not follow the exponentially pattern of decreasing to downstream. This pattern variation is related to different lithological characteristics and difference in the geological units sensitivity to erosion in the river path and sediment supply from the river channel walls. The above factors are caused to decrease selective sorting and abrasion effects and to form two sedimentary discontinuities and three sedimentary links along the Mulid River. Also, as respects the most values of sediments are composed of coarse particles, the selective sorting process that are depended to the grain size, is due to increase of sorting in each sub trends.
In the study area three sedimentary facies sets are observed in the channel walls that are included gravely (Gmm, Gmg, Gci, Gcm, Gh, Gp), sandy (Sh) and muddy (Fm, Fl) sedimentary facies. The gravely facies have the most abundance in the study area and probably are formed by debris flows with high viscosity and power and/ or turbulence flows with high strength shear stress. Sandy facies that has horizontal stratification, is deposited by unidirectional traction currents (lower flow regime). Muddy (Fm, Fl) facies usually are deposited by low energy traction flows or by waning high strength flood events. Also, five architectural elements are recognized based on geometry and boundary surfaces and are used for depositional interpretation. These elements are included channel sediment fills (CH), gravel bars and bedforms (GB), sediment gravity flow deposits (SG), sandy bedforms (SB) and overbank fines (FF).
The wide range of sedimentary processes are controlled the fluvial style. Therefore the river channel morphology usually vary from upstream to downstream that these variations are due to change of some factors such as valley slope, sediment supply, climate and tectonic of the studied area. According to recognized sedimentary facies and architectural elements in the Mulid River channel walls and based on provided models of Miall (2006) two sedimentary models are proposed for this river: a) The gravel- bed braided river with sediment gravity flow deposits and b) the shallow gravel- bed braided river. The difference of a and b models is in frequency of various architectural elements and abundance of sedimentary facies. The first sedimentary model is formed in the proximal and high relief area where the slope, the discharge rate and sediment supply are high and the sediment transported currents are gravity flows. In this reason, the abundance of architectural elements and sandy and fine sedimentary facies that are results of traction currents, are low. In the second sedimentary model, away from the source area, the slope of longitudinal profile of river decreases and therefore the discharge rate of flow and sediment supply decrease. The abundance of debris flows are very low and the sediment gravity flow deposits are not observed in the end parts of rivers. The most important flow that is transported the sediments, is the traction current in this model. In due to decreasing sediment supply and increasing the accommodation space, frequency of sandy and muddy facies are increased with respect to previous model.
The paleohydraulic parameters are estimated with facies variations for three gravely terraces with suitable exposures in three position of the studied river. The capacity and power of paleoflow are calculated using the maximum clast size in the various gravely sedimentary units. The paleodischarge rate estimation is achieved based on channel cross section area and flow velocity. The cross bedding are used to estimate the maximum paleodepth of current. The vertical variation of sedimentary facies, the thickness variation of cross bedding sets and difference clast size are suggested that the hydrologic conditions are fluctuated. The maximum current power and annual discharge rate is compatible with sediment gravity flow deposits (SG element) and the minimum current power and annual discharge rate is related to gravel bars and bedforms (GB element).

The study of electrofacies is a useful petrophysical analysis method in oil-well exploration and evaluation of reservoir characteristics, particularly when the wells lack actual geological data. In order to interpret the electrical facies of the Bangestan group in Ghalea-Nai oil field, three surface sections were chosen and studied for petrographic and petrophysical features. This resulted in the identification of seven microfacies including: wackstone-wackstone, wackstone, sponge (spongy) spicule oligosteginid, bioclast wackstone-packstone, benthic foraminifera rudist wackstone-packstone, peloidal bioclast packstone-grainstone, peloidal microbioclast packstone-wackstone, pelagic foraminifera wackstone-packstone and oligosteginid wackstone-packstone. Porosity percentages and high quality lithofacies of the Bangestan reservoir were identified by "Geolog software", using petrographic data including: neutron, sonic (sound) and resistivity logs on predominant lithology. Based on these results, and also using of lithology determinant intersecting logs, the major identified lithologies are: limestone, dolomite and limestone with minor amounts of dolomite. Based on these results the identified porosity percentages varies between well. No. 3 with 18% (the highest porosity), well No. 2. with about 10% and well No. 4 with 6% (the lowest porosity). The sedimentary microfacies conforming to high quality reservoir were recognized based on electrical investigation and using of MRGC clustering method. This microfacies which belong to Ilam-Sarvak formations are represented by bioclast peloidal packstone-grainstone and sponge spicule oligosteginid packstone-wackstone, respectively.

IntroductionThe Reeg estuary is an important coastal sedimentary environment in the north of the Persian Gulf that is located at the west of the Boushehr Province (Gharibreza, 2005). This basin shows morphology of the bar built estuary and includes three main sections of riverine, lagoon, and marine which is separated from land by the fossil beach. The Reeg estuary is an example of a retrogressive coast that is emerged by sea level fall since Late Quaternary (Gharibreza et al., 2002; Lak et al., 2010). This estuary might be a suitable coastal environment to collect carbonate mud and calcareous oolitic sands assuming similarities between south and north of the Persian Gulf. Determining of Reeg Estuary sediment sources especially carbonate mud and oolitic sands and identification its sedimentary facies were the aims of present research.
Materials and MethodsA comprehensive sediment sampling plan and laboratory analysis were implemented to test the research assumption. Forty-eight sediment samples were taken from different sedimentary facies of the sink and source areas. Thin section of 24 sandy texture samples of the sink and source areas were studied by binocular microscope to identify source of coarse-grained sediments. Composition of sediment was studied using Folk and Ward (1957) method. Distribution of sedimentary facies was studied using geographical information system tools which is widely used around the world (Heap, 2004).
Results and DiscussionCalcimetry tests showed that carbonate content of fine-grained sediments in lagoon section is more than 50%, which was emphasized to suitable chemical conditions for accumulation of carbonate mud. The mean content of the rock fragments, feldspar, and quartz particles were obtained 77±11%, 14±8%, and 9±6%, respectively. Resultant data showed significant profusion of calcareous rock fragments in sediments in both sink and source areas, which represents the Calclithite class of composition. Results also revealed that oolitic sands are the main constituents of marine facies (≈ 90%) particularly along the recent barrier island. In addition, Bakhtiary and Aghajari formations and coarse-grained strata of old and young terraces are the origin of coarse sediments which have been deposited in the Reeg Estuary. Once again, capability of the northern Persian Gulf's coastal sedimentary environments for deposition of carbonate sediments like as what has reported from the southern coasts was proved by present research.
AcknowledgementThe research was supported by Soil Conservation and Watershed Management Research Institute (SCWMRI), Tehran, Iran. The author gratefully acknowledges all academic staffs of coastal protection department for their helps on the implementation of this research.

In this study, four sand dunes, in the East of Babolsar were studied. These dunes are of lunar parabolic type. Their sediment textures are sand and sand with little gravel;.these sediments are moderately sorted, leptokurtic and have positive skewness. More than 60 percent of these deposits are composed of metamorphic and igneous rock fragments. Three sedimentary facies (i.e. A, B1 and B2) were recognized; facies A and B2 show charactertistics of coastal plains and sand dunes; facies B1 were deposited in a swash zone. The age of the middle and lower part of the studied dunes varies from 14 to 25 ka; indicating the minimum and maximum depositional rate of 0.15 and 0.2 mm/y, respectively. Four Radar Facies were recognized; their characteristics are indicative of dune foreslope, cut and trough fill and swash zone.

The Oligocene Qom Formation deposits in NW Central Iran (NE Delijan) are widespread in NE-SW trend.Four members of the QomFormation (unknown, a, b& c1) in the study area consist of mainly marly limestone, limestone, sandy limestone and a minor amounts of sandstone. It disconformablyoverliesthe Lower Red Formation and the upper boundary is covered by the recent alluvium. Based on the benthic foraminifers assemblage, these deposits are attributed to Oligocene (Rupelian- Chattian). Petrographic considerationled to identification of 12 carbonatemicrofacies and one sandstone facies that may have been deposited in a homoclinal ramp and in 4 sub environments including tidal flat, lagoon, bioclastic bar and open marine. Sequence stratigraphy analysis led to identification of 8 3rdordersdepositional sequences bounded by type I and type II sequence boundaries. Comparison between interpreted relative sea level curve with global sea level curve showsreasonable correlation with the lower and upper sequence boundaries of this formation and also Rupelian- Chattianboundary and the differences in other sequence boundaries can be related to local tectonic activity in the sedimentary basin of Qom Formation and the local sea level changes.

Electro-facies is a unit of the vertical sediments sequence on the wire-line logs that can be differentiated from the upper and lower units. For detection of the electro-facies interval in Kangan and upper Dalan formations in south Pars Gas Field، wire-line log and core data analysis (wells A، B، C and D) were used. Note، only core data analysis in well A were available. First، thin-Sections study core plugs from this well resulted in the identification of 12 micro-facies and 7 sedimentary environment. For recognition of electro-fasies based on these data، clustering method and core data were used to categories their homogenization of data. In this study، Rock-Types (R-T) that have similar reservoir characteristics were identified using porosity/permeability cross plot from core data; therefore based on these data، 6 Rock-Type were identified. After classification of Rock-Types and micro-facies from the core data، MRGC models of these facies were identified from the wire-line logs in well A. Optimized model in well A were applied in the wells B، C and D to recognized electro-fasies in these wells with no-core data. Average petro-physical properties of each facies in different wells were compared for quality controls of predicted facies. Also facies of 4 wells were correlated to see if they are comparable. As a result، 6 electro-facies were identified with different petro-physical characteristics and the poorest reservoir quality belong to the facies (1) with dominant anhydrite lithology and the best quality reservoir belong to the facies (6) with the dominant dolomite and limetone with grainstone textue. Due to the high accuracy of the results، the suggested model can be used in other wells in this field.

Primary sedimentary and secondary structural and diagenetic processes are responsible for heterogeneity in carbonate reservoirs and recognition of these factors is very essential subject in modeling these reservoirs. Image logs are very useful for identification of structures and small scale sedimentary features. In this research، using image analysis of Formation Microimager log (FMI) in a drilled well in Dalan Formation، 7 patterns including: 1- band pattern، 2- spot pattern، 3- fracture pattern، 4- drilling induced fracture، 5- cross bedding pattern، 6- block pattern and 7- stylolite pattern are proposed. These patterns were compared with thin sections and core samples. Finally، with combining the FMI results، analyzed by JmicroVision (v. 1. 27) software، with thin sections and core samples of the different facies used to separate the grain supported from mud supported facies. Also among the various diagenetic processes، pressure solution، nodular anhydrite، bioturbation and dissolution were identified in image logs. This study shows that in most cases there is a good synchrony between the results of image logs، thin sections، core samples and well logs.

Tabarak Dam watershed is one of the main water supply of Atrak river, where located at north of Quchan. Geologically, Tabarak Dam watershed is a part of Kopet-Dagh basin.Watershed boundary is marked by Allah-Akbar Mountains and Zoo-Baran anticline. This watershed is divided to Zir-Abeh and Yadak sub-basins. Generally, due to present of different type of rock units, and tectonic effects, two areas, flat plain at Zir-Abeh sub-basin and mountain area at Yadak sub-basin have been formed. According to physiographic features, Tabarak Dam watershed is classified as a mean and elongate basin. The mean high of Tabarak Dam watershed is 1884.96 m, and the average gradient is about 23%. In addition, about 50 of basin shows 20-40 degrees slope. So, this basin is one of the high slope basins in this area. At Tabarak basin, some geomorphologic phenomenons, such as gully, rilly erosin, tallus, alluvial fan and landslide have been identified. Additionlly, different lithology has mostly caused to form drainage patterns such as denderitic and trellis. The identified sedimentary facies are gravelly (Gmm, Gcm), sandy (Sm) and muddy (Fl, Fm, Fr) facies, which are result of effect of physiography, geomorphology and lithology factors of study area.