SH Habibimood; M.N Gorgij; KH Khosrotehrani; A Saidi; S.A Aghanabati
Abstract
The studied section is located in the vicinity of the village Daghal on the Zabol – Nehbandan road, 100 kilometersfrom Zabol. The strata under study are 55.57 meters thick here and lie nonconformably on the igneous rocks while the upper contact is now known. In this study the mentioned strata are ...
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The studied section is located in the vicinity of the village Daghal on the Zabol – Nehbandan road, 100 kilometersfrom Zabol. The strata under study are 55.57 meters thick here and lie nonconformably on the igneous rocks while the upper contact is now known. In this study the mentioned strata are divided into four units lithologically. The results of macroscopic and microscopic studies and the microfacies analysis show that the strata were deposited in four sub-environments including, lagoon, tidal channel, submarine fans and open marine. The thickness and extent of the marine sub-environment is greater than the other sub-environments. The study of microfacies and their constituent sub-environments implies that the mentioned section is formed in a homoclinal carbonate ramp. This study indicates that during the late cretaceous there was a relatively shallow sea covered the area. The existence of microfossils such as Orbitoeides, Omphalosyclus and globutruncana indicates the age of Maastrichtian for the rock unit studied.
L Bakhshandeh1; KH Khosro Tehrani; T Mohtat; S.H Vaziri; F Keshani
Abstract
The Gurpi Formation is located in the Zagros basin, SW Iran . This Formation in the Banroushan section, SW Ilam,consists of 225 m shale with interbeds of marl that has two formal Members including Seymareh (Lopha) and Emam Hassan . These Members are made up of limestone. The lower and upper boundaries ...
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The Gurpi Formation is located in the Zagros basin, SW Iran . This Formation in the Banroushan section, SW Ilam,consists of 225 m shale with interbeds of marl that has two formal Members including Seymareh (Lopha) and Emam Hassan . These Members are made up of limestone. The lower and upper boundaries of this Formation are continuos with the Ilam and Pabdeh Formations. In the present investigation, 46 planktonic species of 13 genera have been identified. The Gurpi Formation is divided into 10 biozone on the basis of planktonic foraminifera which are cosmopolitan and consist of :biozone1-Globotruncanita elevata Partial Range Zone; Biozone2- Globotruncana ventricosa Interval Zone; Biozone3- Globotruncanita calcarata Interval Zone; Biozone4- Globotruncanella havanensis Partial Range Zone; Biozone5- Globotruncana aegyptiaca Interval Zone; Biozone6- Gansserina gansseri Interval Zone; Biozone7-Contusotruncana contusa Interval Zone; Biozone8- Abathomphalus mayaroensis Interval Zone; Biozone9-Parasubbotina pseudobulloides Interval Zone; Biozone 10- Globanomalina pseudomenardii Interval Zone Based on planktonic foraminifera the Gurpi Formation in the study area was deposited during the Early Campanian to Paleocene times.
B Aghababalou; Kh Khosrotehrani; S.M Hoseininezhad
Abstract
The early Carboniferous Mobarak Formation is well exposed in the north of Damghan. It consists of fossiliferous limestone, marly limestone and grey shales. 31 species from 23 genera including: Rossirhynchus adamantinus (Gaetani, 1964), Tomiproductus elegantulus (Tolmmachev, 1924), Pustula cf. altaica ...
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The early Carboniferous Mobarak Formation is well exposed in the north of Damghan. It consists of fossiliferous limestone, marly limestone and grey shales. 31 species from 23 genera including: Rossirhynchus adamantinus (Gaetani, 1964), Tomiproductus elegantulus (Tolmmachev, 1924), Pustula cf. altaica (Tolmachev, 1924), Leptagonia analoga (Phillips, 1841), Hemiplethrorhynchus crassus (Gaetani, 1968), Tylothyris cf. planimedia (Cvancara, 1958), Lamellosathyris aff. Lamellose (Leveille, 1835),Punctospirifer aff. Scabricosta (North, 1920) have been identified from the Labrud section. Four brachiopod assemblage zones show spanning from the Tournaisian to early Visean. The Mobarak Formation at this section overlies the Geirud Formation conformably and underlies the Dorud Formation(?) disconformably.
Kh. Khosrotehrani; D. Baghbani; F. Keshani; M. Omrani
Abstract
In order to study Biostratigraphy of Cenomanian – Late Campanian deposits (upper part of Sarvak Fm.,Ilam Fm. and lower part of Gurpi Fm.), kuhe Assaluyeh stratigraphic section selected. Sediments of this interval consist of limestone, argillaceous limestone and marl with thickness of 162 m. In ...
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In order to study Biostratigraphy of Cenomanian – Late Campanian deposits (upper part of Sarvak Fm.,Ilam Fm. and lower part of Gurpi Fm.), kuhe Assaluyeh stratigraphic section selected. Sediments of this interval consist of limestone, argillaceous limestone and marl with thickness of 162 m. In this section Ilam Fm. in age of Santonian overlies Sarvak Fm. disconformably and is underlain by Gurpi Fm. conformably. By micropaleontological study on 55 thin sections, 5 genus and 9 species of planktonic and 16 genus and 13 species of benthic foraminifers were identified. Among distinguished foraminifers, Rotaliidae family forms were studied carefully and revised. It should be mentioned that, 5 genus and 6 species of benthic foraminifers (Rotaliid forms) were recognized in Iran for the first time (in Assaluyeh section) which consist of: Rotorbinella mesogeensis,Rotorbinella campaniola,Iberorotalia reicheli,Calcarinella schaubi, Pararotalia tuberculifera and Pyrenerotalia longifolia. Santonian age was determined for Ilam Fm. by identified foraminifers. In studied section, stratigraphy development of benthic foraminifers was compared by Martinez Biozones Martinez (2007). This biozones were presented on the base of Rotaliid forms for Pyrenees area in Spain. By this comparison, four biostratigraphy zones for upper part of Sarvak and Ilam Fm. are suggested.
V. Hosseini toudeshki; M. Pourkermani; M. Arian; Kh. Khosrotehrani
Abstract
Rivers are the most important landforms on the ground whose analysis is known as a useful tool in tectonic surveys in several thousands to two million years ago. The Ghezel Ozan River, the longest river system in the country, has responded to tectonic deformation thoroughly. Detection and characterization ...
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Rivers are the most important landforms on the ground whose analysis is known as a useful tool in tectonic surveys in several thousands to two million years ago. The Ghezel Ozan River, the longest river system in the country, has responded to tectonic deformation thoroughly. Detection and characterization of geomorphic anomalies in the Ghezel Ozan River and correlation with structures can specify the role of structures in making active deformations. The intense and sudden deflection in the river course, the abnormal changes in the river sinuosity and knick points upon longitudinal profile of the river are the geomorphic anomalies connected to the structures. Deflection of the river course and abnormal changes in the river sinuosity are identified on the satellite images and approved through field observations. Knick points are specified upon longitudinal profiles of the river and the effects of lithology are surveyed in making of them٫ so that only knick points are considered which are produced by structures. Longitudinal profiles of the river have been obtained from digital elevation model. Above mentioned anomalies then have been correlated with structures extracted from geology maps and in this manner structures effective in making geomorphic anomalies have been identified. The study region is located in Sanandaj – Sirjan, Centeral Iran and Western Alborz zones. Around the Ghezel Ozan River, marl, sandstone, siltstone, limestone, tuff, agglomerate and volcanic rocks are extremely exposed. These rocks belong to Qom, Upper Red, Lower Red and karaj formations. Deflection of the Ghezel Ozan River is surveyed in the regions of Kuh-e-Palangi, Jelovdarlou, Cham and Yengejeh. Abnormal changes in river sinuosity is studied in regions of Jomaelou, Gol gheshlagh, Armoutlou, Kuh-e-Qaravol, Ghaflankuh and Kuh-e-Pajdar. In the regions of Sharif Abad, Iemir, Kuh-e-Qaravol and Kuh-e-Pajdar, knick points are specified upon longitudinal profile of the Ghezel Ozan River. The obtained results show that folds with trends of NW – SE and NE – SW have the highest influence on deflection of the course of the Ghezel Ozan River. The other geomorphic anomalies produced by faults with trends of NW–SE , NE – SW, N-S and E-W especially in instances that faults with trends of NW – SE and NE – SW have intersected. Thus, the most active structural trends in around of the Ghezel Ozan River are trends of NW–SE, NE – SW, N-S and E-W which correlate with trends of fractures in basement of Iran. In this way active folds and faults are identified in the area.
Z. Mardani; M. Ghorashi; M. Arian; Kh. Khosrotehrani
Abstract
Geomorphic indices of active tectonics are useful tools to analyze the influence of active tectonics.These indices have the advantage of being calculate from ArcGIS and remote sensing packages over large area as a reconnaissance tool to identify geomorphic anomalies possibly related to active tectonics.This ...
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Geomorphic indices of active tectonics are useful tools to analyze the influence of active tectonics.These indices have the advantage of being calculate from ArcGIS and remote sensing packages over large area as a reconnaissance tool to identify geomorphic anomalies possibly related to active tectonics.This is particulary valuable in west-central Alborz where relatively little work on active tectonics based on this method was done,so this method is new and useful. Based upon values of the stream length-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley-floor width to valley height (Vf), index of drainage basin shape (Bs), and index of mountain front sinuosity (Smf),we used an overall index(Iat) that is a combination of the other indices that divides the landscape into four classes of relative tectonic activity. The moderat class of Iat is mainly in the south of Manjel dam,while the rest of the study area has high active tectonics (shahrud drainage basin and sefidrud drainage basin),and high to very high(Taleghan and Alamut drainage basin). The stream network asymmetry (T)was also studied using morphometric measures of Tranverse Topographic Symmetry.Analysis of the drainage basins and subbasins in the study area results in a field of T-vectors that defines anomalous zone of the basin asymmetry.Acomparsion of T index clearly coincide with the values and classes of active tectonics indices and the overall Iat index.
J. Daneshian; D. Baghbani; Kh. Khosrow- Tehrani; L. Fazli
Abstract
In this study, foraminifera of the Ilam and Gurpi Formations, from Kuh-e- Assaluyeh section in east Kangan port in Boushehr province and Ivan well in Persian Gulf are investigated. Ilam Formation in Kuh-e-Assaluyeh section with 30 meter thickness and Ivan well with 68 meter thickness composed of limestone ...
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In this study, foraminifera of the Ilam and Gurpi Formations, from Kuh-e- Assaluyeh section in east Kangan port in Boushehr province and Ivan well in Persian Gulf are investigated. Ilam Formation in Kuh-e-Assaluyeh section with 30 meter thickness and Ivan well with 68 meter thickness composed of limestone and dolomitic limestone. The Ilam Formation in the study sections overlies unconformable the Sarvak Formation and underlies the Gurpi Formation. The Gurpi Formation in Kuh-e-Assaluyeh with 73 meter thickness and Ivan well with 56 meter thickness composed of argillaceous limestone, sandy limestone, shale and limestone. Also the Gurpi Formation in Kuh-e-Assaluyeh section and Ivan well overlies unconformable the Ilam Formation and underlies the Pabdeh Formation. The study of 70 samples from the examined section led to the identification of 13 genera and 19 species of planktonic foraminifera and 12 genera and 12 species of benthonic foraminifera. Planktonic foraminifera are as follow: Heterohelix globolusa, Macroglobigerinelloides ultramicrus, Globotruncanita elevata, Globotruncana bulloides, Globotruncana ventricosa, Muricohedbergella holmdelensis, Heterohelix striata, Macroglobigerinelloides prairiehillensis, Contusotruncana fornicata, spiropelecta sp., Rugoglobigerina rugosa Macroglobigerinelloides bollii, Muricohedbergella monmouthensis, Globotruncana falsostuarti, Gansserina gansseri, Archaeoglobigerina blowi, Globotruncana arca, Contusotruncana contusa, and benthonic foraminifera are as follow : Rotalia sp., Rotalia skourensis, Pseudedomia sp., Minouxia sp., Dicyclina schlumbergeri, Quinqueloculina sp., Marssonella sp., Gavelinela sp., Archaecyclus midorientalis, Ammobaculites sp. On the basis of stratigraphic distribution of index foraminifera, the Ilam Formation belongs to Santonian to Campanian, and the Gurpi Formation in Kuh-e-Assaluyeh section is Campanian to Maastrichtian and in Ivan well is Maastrichtian in age. The studies in Kuh-e-Assaluyeh section let to recognition four foraminifera zone from base to top: Globotruncanita elevata Zone, Globotruncana ventricosa Zone, Globotruncana falsostuarti Zone, Gansserina gansseri Zone. Lacking the main elements of Globotruncanella havanensis and Globotruncana aegyptiaca biozones caused that Globotruncana falsostuarti biozone is introduced on the basis of the first occurances of Globotruncana falsostuarti (at the base) and Gansserina gansseri (at the top). Also in Ivan well, Globotruncana falsostuarti Zone, Gansserina gansseri Zone, Contusotruncana contusa Zone were identified. Abathomphalus mayaroensis in absent at Ivan well and Kuh-e-Assaluyeh. Thus, Abathomphalus mayaroensis biozone is not recognizable, and instead of it Contusoutruncana contusa biozone is introduced. The boundaries of this biozone are identified by the first and last occurrences of Contusoutruncana contuse. Also comparison this study with Biozonation of Wynd, (1965), from base to top: 1-Rotalia sp. 22, Algae assemblage zone, 2- Archaecyclus midorientalis-Pseudedomia sp.assemblage zone, 3- Globotruncanita elevata zone, 4- Globotruncanita stuarti-Pseudotextularia variance assemblage zone. 5- Contusoutruncana contusa zone.
R. Khavari; M. Ghorashi; M. Arian; Kh. Khosrotehrani
Abstract
The paper presents a method for evaluating relative active tectonics based on geomorphic indices useful in evaluating morphology and topography. Indices used include: stream length-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley-floor width to valley height ...
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The paper presents a method for evaluating relative active tectonics based on geomorphic indices useful in evaluating morphology and topography. Indices used include: stream length-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley-floor width to valley height (Vf), index of drainage basin shape (Bs), and index of mountain front sinuosity (Smf). Results from the analysis are accumulated and expressed as an index of relative active tectonics (Iat), which divided into four classes from relatively low to highest tectonic activity. The study area along the south flank of the central Alborz mountain range in north Iran is an ideal location to test the concept of an index to predict relative tectonic activity on a basis of area rather than a single valley or mountain front. The recent investigations show that neotectonism has played a key role in the geomorphic evolution of this part of the Alborz mountain range. Geomorphic indices indicate the presence of differential uplifting in the geological past. The high class values (low tectonic activity) for Iat mainly occur in the south and southeast of the Karaj drainage basin, while the rest of the study area has classes of Iat suggesting moderate to high tectonic activity. Around the Amirkabir Lake, Iat has the highest value. The distribution of the indices defines areas associated with different mountain fronts and estimates of relative rates of tectonic activity. More than half of the study area is classified into classes 2 or 1 of high to very high tectonic activity in terms of the apparent geomorphic response. In different tectonic environments with greater rates of active tectonics, the values of indices would differ as well as their range in value. The stream network asymmetry (T) was also studied using morphometric measures of Transverse Topographic Symmetry. Analysis of the drainage basin and a number of sub-basins in the study area results in a field of T-vectors that defines anomalous zones of the basin asymmetry. We test the hypothesis that areas with great stream migration are associated with indicatives values of Iat.
A.H. Kokabi Nezhad; Z. Purabrishami; Kh. Tehrani
Abstract
One of Hipparion species which has complete characters of cranium and maxillary with teeth found during excavation is H.primignium. Since this sample is the only complete one in the world, (of course without mandible) with special species characters we can call it Homeotype. Because of finding this species, ...
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One of Hipparion species which has complete characters of cranium and maxillary with teeth found during excavation is H.primignium. Since this sample is the only complete one in the world, (of course without mandible) with special species characters we can call it Homeotype. Because of finding this species, pyroclastic sediments of Maragheh would be dated upper Astracian, so Maragheh informal formation which in the past was thought to be as old as vallencian- Trulain, seems a bit older. Because the mentioned samples were also found in Samus and Pikermi in Greece, so we can say these two regions have vertebrate familiarities in fossils fauna and other characters like paleogeography, biochronology and biogeography in late Miocene- early Pliocene.
F. Hadavi; K. Khosrow Tehrani; S. Senemari
Abstract
Nannofossils are good for biostratigraphy, since they are abundant, planktonic, rapidly evolving and largely cosmopolitan especially in the Late Cretaceous. With respect to this reality and due to the lack of any precise paleontological study, the nannofossils of Gourpi Formation were investigated in ...
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Nannofossils are good for biostratigraphy, since they are abundant, planktonic, rapidly evolving and largely cosmopolitan especially in the Late Cretaceous. With respect to this reality and due to the lack of any precise paleontological study, the nannofossils of Gourpi Formation were investigated in the north of Gachsaran. This formation consists of marl and clay limestone.
In this study, for the first time, 23 genera and 43 species of nannofossils were identified. Based on the obtained nannofossils, the study section is Late Santonian to Late Maastrichtian in age corresponding to CC16-CC26.