F Shirezadeh Esfahani; N Kohansal Ghadimvand; A Kangazian; S.H Hejazi; V Hairapetian
Abstract
The Vazhnan Formation in the Shahreza-Abadeh belt, apparently extending from latest Carboniferous to Asselian, consists of conglomerate, limestone, sandstone and shale, which is correlative to the Dorud Formation of the Alborz Mountains and the Zaladou Formation of Central Iran. This work is presenting ...
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The Vazhnan Formation in the Shahreza-Abadeh belt, apparently extending from latest Carboniferous to Asselian, consists of conglomerate, limestone, sandstone and shale, which is correlative to the Dorud Formation of the Alborz Mountains and the Zaladou Formation of Central Iran. This work is presenting some results on revision of the lithostratigraphy of the Vazhnan Formation in the Tang-e-Darchaleh section (northeast of the Shahreza town). Introduction of this interval in the Banarizeh section (north of the Abadeh town) and correlation of the Vazhnan Formation in the sections understudied are other purposes. Based on the results of this study, Vazhnan Formation in the Tang-e-Darchaleh (as the type section) and Banarizeh (as the reference section) section is distinguished with the distinct eroded surface at the base and rests disconformably on the sandstones of Late Carboniferous, corresponding to the Sardar Formation. The upper part of this interval is disconformably overlain by the Surmaq Formation (late Early–Middle Permian) in the Banarizeh section. Field investigations revealed that the contact between the Vazhnan and Surmaq Formations in the Tang-e-Darchaleh section is faulted. The vertical and lateral changes of the lithofacies in the Vazhnan Formation indicate the depositional system which is evolved from a distal into a homoclinal ramp setting.
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.
S.A Aleali; H. Rahimpour-Bonab; S. R. Moussavi -Harami; D. Jahani; A. Asadi-Eskandar
Abstract
The Early Triassic carbonates of Kangan Formation are major gas reservoirs in the Southwest of Iran and the northern Persian Gulf. Facies analyses of Kangan Formation led to recognition of 13 microfacies which are related to tidal flat, lagoon, shoal and open marine environments. Examination of vertical ...
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The Early Triassic carbonates of Kangan Formation are major gas reservoirs in the Southwest of Iran and the northern Persian Gulf. Facies analyses of Kangan Formation led to recognition of 13 microfacies which are related to tidal flat, lagoon, shoal and open marine environments. Examination of vertical and lateral facies changes and thire comparison with their modern and ancient counterparts, all indicate that Kangan Formation were deposited in a shallow carbonate ramp platform similar to the present day Persian Gulf. The sequence stratigraphic studies showed that the Kangan Formation consists of two third order depositional sequences (in the A and B wells), each consisting of transgressive and highstand systems tracts. The lower boundary of the first sequence is a type 1 unconformity, but other boundaries are type 2 unconformity. Typical reservoir zone in the Kangan Formation is dominated in early highstand systems tract deposits and concentrated in shoal grainstone facies. However, in this paper, typical intervals such as sequence boundaries, maximum flooding surfaces, stacking patterns and system tracts were studied.
A. Karimian Torghabeh; S.R Moussavi-Harami; A. Mahboubi
Abstract
Siliciclastic succession of Pesteliegh Formation, Lower Paleocene, has an extensive exposure in the Kopet Dagh basin. Three stratigraphic sections, consist of Dareh Gaz, Shamsikhan and Karnaveh in central Kopet Dagh, were measured and studied for environmental interpretation and sequence stratigraphic ...
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Siliciclastic succession of Pesteliegh Formation, Lower Paleocene, has an extensive exposure in the Kopet Dagh basin. Three stratigraphic sections, consist of Dareh Gaz, Shamsikhan and Karnaveh in central Kopet Dagh, were measured and studied for environmental interpretation and sequence stratigraphic analysis. This study led to identification of 8 lithofacies (Gcm, Gmg, Gt, Sm, Sh, Sp, St و Fm) and 5 architectural elements ( OF, CH, SB,GB,SG). Based on this data, siliciclastic sediments of Pesteliegh Formation were deposited in both fine-grain meandering and braided river systems. Sequence stratigraphy analysis show that siliciclastic sediments of the Pesteliegh Formation deposits is composed of two depositional sequences that were effected by tectonic and base level changes during the sea level fall. Both depositional sequences consist of LE and TE phases. Paleogeographic reconsruction of the Early Paleocene time show that these deposits were formed during 4 different stages in relation to changes in accommodation space.
M. Hosseini-Barzi; N. Etemad Saeed
Abstract
The Early Cambrian Lalun Formation in Poshte- Badam block has been studied in Bahmoo section with 550 m thickness, to illuminate its sedimentary environment and sea level changes. The field investigations, collection of 110 paleocurrent data, petrography, study of SEM images and XRD analysis of shale ...
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The Early Cambrian Lalun Formation in Poshte- Badam block has been studied in Bahmoo section with 550 m thickness, to illuminate its sedimentary environment and sea level changes. The field investigations, collection of 110 paleocurrent data, petrography, study of SEM images and XRD analysis of shale samples have been used for facies analysis, paleocurrent recognition and sedimentary environment reconstruction. The facies analyses imply 5 silisiclastic coarse grained (Gm), medium grained (Sp, St, Sh) and fine grained (Fl) lithofacies and 1 carbonate (dolomite) microfacies. The lithofacies, bipolar bimodal paleocurrent pattern and petrographic evidences such as the existence of glauconitic sandstones with high textural and compositional maturity imply deposition of these sediments in a Tidal Flat environment. Studying the relative sea level changes of Lalun deposits in this area imply two sequences which have been bounded between SB1 unconformities.
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.