H Ghaderi Fijani; M Khanehbad; R Moussavi Harami; A. Mahboubi
Abstract
The elongated Elyato River catchment, covering about 52.89 Km2 areas, is located in southwestern Fariman. To understand the grain size variation and effective factors in downstream fining, 35 samples from central axis of Longitudinal Bars have been collected and analyzed. The results indicate that the ...
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The elongated Elyato River catchment, covering about 52.89 Km2 areas, is located in southwestern Fariman. To understand the grain size variation and effective factors in downstream fining, 35 samples from central axis of Longitudinal Bars have been collected and analyzed. The results indicate that the grain size decreases downstream as exponential. The lithological and geomorphological changes and faulting are effective in the slope percentage changes downstream. Based on petrographic studies, sediments on the river’s substrate are igneous rock fragments such as gabbro and serpentine group. However, based on sedimentological studies, we show that the sediments of Longitudinal Bars are mostly poorly and very poorly sorted, near symmetrical to very positive skewness and mesokurtic and platy kurtic kurtosis. Six sedimentary facies including grain supported gravel (Gcm), matrix supported gravel (Gmm), grain supported gravel with horizontal bedding (Gh), massive sand (Sm), laminated mud (Fl) and massive mud (Fm) are recognized along the wall of the studied river. These sedimentary facies have formed in 3 architectural elements including channel (CH), Gravel bars and bed form (GB) and fine grain clastic deposits (FF). Based on sedimentary facies and architectural elements, sedimentary model for this river is proposed as gravelly braided river system.
E Khazaei; M.H Mahmudy Gharaie; A Mahboubi; J Taheri
Abstract
The studied section in SW Kashmar located in Tabas block of central Iran sedimentary - structural zone. According to field observations and petrography, two sets of siliciclastic and carbonate facies were distinguished. Three lithofacies were identified based on the field parameters such as lithology, ...
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The studied section in SW Kashmar located in Tabas block of central Iran sedimentary - structural zone. According to field observations and petrography, two sets of siliciclastic and carbonate facies were distinguished. Three lithofacies were identified based on the field parameters such as lithology, geometry, sedimentary structures, layering surfaces and bedding contacts. Three lithofacies including conglomerate (Gcm, Gp), Sandstone (St, Sr, Sh, Sl, Sm), muddy (Fl), four petrofacies (polymictic orthoconglomerate 1 and 2, arkosic wacke, and subarkose as well as four microfacies associations of open marine, shoal, lagoon, tidal flat were identified based on microscopic features such as grain type, grain size and texture. Based on finning upward Bouma cycles, erosional surface and greywacke composition, siliciclastic sediments of upper part of the Shirgesht Formation are deposited in turbidity conditions. Present of hummocky stratification, finning upward cycles with shellbeds at the base of units revealed that carbonate rocks of lower part of the Niur Formation are deposited in a shallow ramp storm - dominated. The regional tectonic, expansion of glaciers and melting led to environmental changes during Upper Ordovician – Early Silurian transition in the studied region.
N. Sarbaz; A. Mahboubi; R. Moussavi-Harami; M. Khanehbad
Abstract
The Koppeh- Dagh Basin in the northeast Iran formed after closure of the Paleotethys in the south of Turan plate. Kashafrud Formation in the Navia Section (west of Bojnourd) with a thickness of 749 m is composed of silici-clastic rocks (conglomerate, sandstone and shale). In order to interpret provenance ...
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The Koppeh- Dagh Basin in the northeast Iran formed after closure of the Paleotethys in the south of Turan plate. Kashafrud Formation in the Navia Section (west of Bojnourd) with a thickness of 749 m is composed of silici-clastic rocks (conglomerate, sandstone and shale). In order to interpret provenance of this formation in the study section, 12 shale samples have been geochemically analyzed. The samples are rich in quartz and clay minerals, with respect to (UCC) depletion in Na2O, CaO, MgO, Cu, Nb and Sr and enrichment in Ni, Co, V, Y and U. Plotting TiO2 versus Al2O3, Zr versus TiO2, as well as ternary diagram (SiO2/20), (k2O+ Na2O), (MgO+ TiO2+ FeO) and diagram Al2O3, (Cao+ Na2O+ K2O), (FeO + MgO) suggest that the original source of this formation was probably from intermediate igneous rocks. Calculated PIA and CIA indicate high chemical weathering and semi- humid climatic condition in the source area. Prepared discrimation diagram using the major oxides (SiO2 versus K2O/Na2O and ternary diagrams SiO2/20, Na2O+ K2O, TiO2+ MgO+ Fe2O3), shows that the shales of this formation were plotted in the passive continental margin. Paleogeographic reconstruction for this formation, during the Middle Jurassic shows that sedimentation of this formation is mainly controlled by intracontinental subsiding basin and the source of these sediments was from the southeast of the Kopph-Dagh Basin.
M Afarin; M Boomeri; A Mahboubi; M Gorgij; M.A Hamzeh
Abstract
In this study, geochemical and sedimentological assessment was carried out on mudstone and sandstone deposits of Eastern coasts of Chabahar. Fifty samples were taken from five sectione of Tiss, Ramin, Lipar, Gorankesh and Garindar estuary and subjected to grain size analysis and chemical analysis ...
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In this study, geochemical and sedimentological assessment was carried out on mudstone and sandstone deposits of Eastern coasts of Chabahar. Fifty samples were taken from five sectione of Tiss, Ramin, Lipar, Gorankesh and Garindar estuary and subjected to grain size analysis and chemical analysis using XRF and ICP AES methods. Positive sorting and skewness (with the frequency of fine grain particles) of samples indicate deposition in a low energy environment. Plotting geochemical data of major elements from Late Miocene- Pleistocene age 10 mudstone and sandstone samples in east coasts of Chabahar in Makran zone, on siliciclastic rocks classification diagrams, showed that the sandstones are wacky and Mudstones are shale. The mean calculated chemical indexes of alteration (CIA) and weathering (CIW) for siliciclastic sediments, confirm low level weathering of source rocks of this sediments. The average index of combinational variety (ICV) for the studied sediments was 1.57, which indicates that these deposits have a moderate chemical maturity and are derived from the first cycle of sediments. Distribution pattern of rare earth elements on spider diagrams shows the enrichment of light rare earth elements (LRRE) relative to heavy rare earth elements (HRRE) in the rocks. High ratios of LILE/HFSE and LRRE/HRRE in the rock samples and similarity of their chemical composition with subduction zone facies, indicates that siliciclastics of Chabahar coasts have formed in a subduction zone. The diagrams of tectonic setting associated with patterns of multivariate charts also shows that the studied rocks have been developed in an active continental margin.
Y Noorian; S.R Moussavi Harami; A Kadkhodaie; A Kadkhodaie; S.A.A Abdolahi Mousavi
Abstract
Rock typing by different techniques is useful to interpret the zoning of reservoir. As the hydraulic flow unit has an effective connectionbetween the geological and petrophysical conditions, recognition of distribution quality of flow units in a reservoir can be useful for separation of reservoir into ...
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Rock typing by different techniques is useful to interpret the zoning of reservoir. As the hydraulic flow unit has an effective connectionbetween the geological and petrophysical conditions, recognition of distribution quality of flow units in a reservoir can be useful for separation of reservoir into different units with different reservoir conditions. In this study, by using of flow zone indicator (FZI), six flow units has been determined based on the porosity and permeability data in both wells A and B of the Bangestan reservoir in the MansouriOil Field. The main statistical parameters of Porosity and permeability data for each of flow units (HFU) shows HFU3andHFU1 have the highest and HFU5 and HFU6 have the lowest reservoir quality in the oil field. In order to cluster validity, silhouette approach was used to hierarchical and K-means clustering methods and finally hierarchical clustering was selected as the best method and the porosity and permeability data for both wells were included in the six clusters (RT). Comparison between Hierarchical clustering method with the flow units and microfacies indicated acceptable results for both methods.
M Karavan; A Mahboubi; H Vaziri-Moghaddam; R Moussavi-Harami
Abstract
The Oligocene Qom Formation deposits in NW Central Iran (NE Delijan) are widespread in NE-SW trend.Four members of the Qom Formation (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 ...
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The Oligocene Qom Formation deposits in NW Central Iran (NE Delijan) are widespread in NE-SW trend.Four members of the Qom Formation (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.
M.A Salehi; S.R Mousavi-Harami; A Mahboubi; B Rahimi
Abstract
The Lower Jurassic Ab-Haji Formation consists of siliciclastic sediments, which are widely exposed in the Tabas Block. This formation varies in thickness from tens of meters to more than 500 m in northern Tabas Block. The Ab-Haji Formation with avearge thickness of 75 meters presents in the Tabas Coal ...
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The Lower Jurassic Ab-Haji Formation consists of siliciclastic sediments, which are widely exposed in the Tabas Block. This formation varies in thickness from tens of meters to more than 500 m in northern Tabas Block. The Ab-Haji Formation with avearge thickness of 75 meters presents in the Tabas Coal Mine area and consists mainly of sandstone, siltstone, claystone with a few thin interbeds of coal seams. Two outcrops and three exploration boreholes were studied in order to identify lithofacies and to interpret the depositional environment. The lithofacies analysis in outcrops imply two siliciclastic coarse grained (Gcm, Gt), four medium grained (St, Sp, Sr, Sh), two fine grained (Fl, Fm) and one coal lithofacies. Identified lithofacies can be grouped into four architectural elements including channel, point bar, crevasse splay and coastal plain swamps. The electorofacies and log motif analysis led to recognition and differentiation of architectural elements in exploration boreholes. The lithofacies and architectural elements show that the siliciclastic sediments of the Ab-Haji Formation were deposited in the meandering river system within a coastal plain with widespread swamps. The sedimentological analysis led to reconstruction of paleogeography in eastern part of the Tabas Block, which shows deposition of nonmarine to coastal plain environment in this part of the block.
K Shabani Goraji; R Moussavi-Harami; A Mahboubi; Kh Khosro Tehrani
Abstract
The provenance and tectonic setting of the Eocene turbidite sandstones of the Saravan area in southeast of Iran have been studied based on petrography and geochemistry. These sandstones are very laterally extended and traceable at several kilometers. The sandstones are sharp-based and well-preserved ...
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The provenance and tectonic setting of the Eocene turbidite sandstones of the Saravan area in southeast of Iran have been studied based on petrography and geochemistry. These sandstones are very laterally extended and traceable at several kilometers. The sandstones are sharp-based and well-preserved and generally display Bouma sequences (Tbcde, Tabc, Tbcd, Tabcd) which consist of graded bedding, flute and groove casts, planar cross lamination, current ripples and parallel lamination. The deep water trace fossils (Nereites ichnofacies) are locally abundant. These characteristics support sedimentation by the turbidity current. The petrographical data show that these sandstones are fine to coarse grained, poorly to moderately-sorted, sub-angular to sub-rounded feldspatic litharenite. They contain mono- and poly-crystalline quartz grains, feldspar, volcanic and metamorphic rock fragments and represent Q55F14.7L30.3 proportion. The major, trace and rare earth element concentrations indicate that the source of these sediments were intermediate to felsic igneous rocks. Mean value of chemical index of alteration in analyzed samples (CIA mean ≈ 62) indicate a low to moderate degree of chemical weathering of the source area or during the sediments transportation prior to deposition.The petrographic analysis revealed a recycled orogen and transitional recycled tectonic provenance. Tectonic setting discrimination based on the major, trace and rare earth elements suggest that the Saravan sandstones components derived from an active continental margin and continental arcs.
A. Bayet-Goll; R. Moussavi-Harami; A. Mahboubi
Abstract
Trace fossils are abundant in the clastic succession throughout the Shirgesht Formation of Kalmard Block, Central Iran. At certain horizons there are beds full of Cruziana and Rusophycus. This study presents an evaluation of the arthropod ichnotaxa of the Cruziana and Rusophycus from the Ordovician succession ...
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Trace fossils are abundant in the clastic succession throughout the Shirgesht Formation of Kalmard Block, Central Iran. At certain horizons there are beds full of Cruziana and Rusophycus. This study presents an evaluation of the arthropod ichnotaxa of the Cruziana and Rusophycus from the Ordovician succession Shirgesht Formation. Apart from the broad range in morphology and size, Cruziana from Shirgesht Formation show higher behavioral diversity using food sources than has ever been documented in a single section. It consists of a straight, or gently curved, ploughed furrow usually a few centimetres across, which is divided lengthwise into two lobes, each of which is braided transversely by a series of scratches. These vary in arrangement and profile according to ichnospecies. Overall characteristics of recognized ichnospecies suggest that with the exception of C. semiplicata, the ichnofaunas contain all the members of the Cruziana rugosa Group throughout the clastic successions in Shirgesht Formation. It consists of the five members of C. rugosa, C. furcifera, C. goldfussi C. rouaulti and C. yini. The Shirgesht Formation material therefore indicates that these arthropod ichnofossil assemblages are suitable for Cruziana ichnostratigraphy in Shirgesht Formation. Accordingly, the present assemblage could represent the Early to middle Ordovician age. The arthropod traces also, occur with other biogenic sedimentary structures in a fine to medium grained sandstone with minor mudstone interbeds of the Shirgesht Formation. The substrate composition and ichnological evidence places the arthropod ichnofossil-rich unit in the Cruziana ichnofacies.
A. Bayat Gol; N. Abbassi; A. Mahboubi; R. Moussavi-Harami; H. Amin Rasouli
Abstract
Some of Paleozoic sediments from Alborz and Central Iran subzones from Mid-Iran zone evaluated for distinction of Palaeophycus and Planolites ichnofossils. These sediments include Shale Member of Lalun Formation, Shirgesht Formation, member 5 of Mila Formation and Geiroud Formation. A diverse ichnofauna ...
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Some of Paleozoic sediments from Alborz and Central Iran subzones from Mid-Iran zone evaluated for distinction of Palaeophycus and Planolites ichnofossils. These sediments include Shale Member of Lalun Formation, Shirgesht Formation, member 5 of Mila Formation and Geiroud Formation. A diverse ichnofauna has been found in these Formations, so Planolites and Palaeophycus are abundant between them. Ichnotaxa diagnosis and some determination problems of these ichnogenera was discussed here. Overall characteristics of Palaeophycus suggest dwelling structure made by predator or suspension-feeder and passive sedimentation in the open burrow. Planolites, on the other hand imply active backfilling structure in ephemeral burrows, which constructed by a mobile deposite-feeder. Planolites include unlined burrows with infilled sediments differ texturally from host rock. Whereas Palaeophycus is lined burrow filled by same sediments of surrounding matrix. Accordingly, Palaeophycus assemblage members made by opportunistic communities with r-selected population strategies in physically-controlled and unstable environment, whereas ichnofossils of Planolites assemblage are related to benthic communities with displaying K-selected or climax strategies in the stable environments and rather predictable conditions. Recognized ichnospecies of Planolites are P. montanus, P. annularis, P. terraenovae and P.beverleyensis. and ichnospecies of Palaeophycus include P. heberti, P. tubularis, P. striatus. P. sulcatus and P. alternates.
S. R. Moussavi-Harami; Y. Nasiri; A. Mahboubi; A. Bayetgoll
Abstract
Amiran Formation (Paleocene) in Lorestan, folded Zagros zone, contains a diverse and exceptionally well preserved ichnofauna. A quantitative study of trace fossil in the Paleocene deep-marine clastic systems, this Formation, shows that they are powerful discriminators of submarine fan and related environments. ...
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Amiran Formation (Paleocene) in Lorestan, folded Zagros zone, contains a diverse and exceptionally well preserved ichnofauna. A quantitative study of trace fossil in the Paleocene deep-marine clastic systems, this Formation, shows that they are powerful discriminators of submarine fan and related environments. The host lithologies are conglomerates, sandstones, siltstones and mudstones. These sediments are interpreted to be deposits in upper to lower-fan palaeoenvironment. Channel deposits consist of thick-bedd turbidite and interchannel deposits are interpreted to be deposited by unconfined debris flows and high concentration turbidity currents. The ichnofauna with high diversity is most frequently, and best, preserved within the Tcde interval of turbidities, which are interpreted as interchannel deposits, produced by low concentration turbidity flows. On the basis of trace fossil diversity, ichnotaxonomic composition, ethology, and morphologic complexity, trace fossils assemblage were grouped into pre-depositional or post-depositional forms. The predepositional assemblage is rich in graphoglyptids and grazing trails, and feeding structures. The ichnodiversity, ethology, and morphologic complexity of the predepositional association are indicative of the Nereites ichnofacies. The postdepositional association essentially consists of dwelling and feeding traces. The post-depositional association includes elements of the Skolithos ichnofacies. Overall characteristics of trace fossils suggest that from the proximal to the distal environment of Amiran Formation, proportions of domichnia trace-fossil assemblages decreases while agrichnia, fodinichnia and pascichnia increases.
M. Khoddami; A. Mahboubi; R. Moussavi-Harami; S. Feiznia
Abstract
The Lateshur Watershed is a part of Central Iranian drainage basin located northeast of the city of Pakdasht in northeastern TehranProvince. This watershed has an elongate form and its surface area is more than 22.2 square kilometer. It is a part of central Alborz zone and geologically is composed of ...
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The Lateshur Watershed is a part of Central Iranian drainage basin located northeast of the city of Pakdasht in northeastern TehranProvince. This watershed has an elongate form and its surface area is more than 22.2 square kilometer. It is a part of central Alborz zone and geologically is composed of Neogen red beds units, Hezardareh Formation and Quaternary alluviums. Geomorphologic studies show that this watershed is within an anticline and surrounded by DahanehMountains in the south and Gara-aghajMountains in the north respectively. Structural and lithological variability have a very important role in the formation of this watershed; therefore, the watershed has the same trend as structures (NW-SE). Based on this study, the LateshurRiver has a braided pattern with gravelly bed. Sedimentological studies along rivers in Lateshur basin show that three basic factor (sudden changes in slope gradient, floods events and distributaries) are the main reasons for changes in texture of bed load sediments within the channel as well as the break in sedimentary links. Lithofacies identified in this watershed include gravelly (Gmm, Gmg, Gcm, Gt), sandy (Sp, Sm, St, Sh) and muddy (Fl, Fr). Based on lithofacies, Boundary surface and current direction architecture elements identified in main river of Lateshur basins include: (1) Gravel bars and Bed forms [Element GB], (2) Lateral Accretion deposits [Element LA], (3) Sandy bed forms [Element SB] and (4) Fine grain classtic deposits [Element FF]. Also, based an lithofacies and architectural elements, Facies models have been purposed for the Lateshur river from upstream toward downstream as fallows: Shallow gravel braided river, Gravel wandering river, Gravel bed meandering river, Sandy meandering rive and Fining grain meandering river.
