The lower Cretaceous rock units of the Koppeh-Dagh Basin of northeastern Iran were investigated here in terms of biostratigraphy,depositional setting and geochemical analyses to find out if they,alike other parts of t...The lower Cretaceous rock units of the Koppeh-Dagh Basin of northeastern Iran were investigated here in terms of biostratigraphy,depositional setting and geochemical analyses to find out if they,alike other parts of the world,are rich in petroleum.For this purpose,a stratigraphic framework is established using calcareous nannofossil and palynological elements.A nannoplankton zonation based on which subzones of the zones CC7–CC8 of Sissingh(1977)and their equivalent NC6–NC8 of Roth(1978)was established indicating a Late Barremian–Albian age.Palynological assemblages led us to establish the local palynozone of Odontochitina operculata.A dominantly marginal basin to a transitional zone between shelf and basin under a dysoxic–anoxic condition with low to moderate sedimentation rates coincided with a gradual sea level rise was introduced as the environment of deposition for the strata via interpretation of the palynological parameters and quantitative palynology.The obtained data from Rock-Eval pyrolysis in compilation with palynofacies analysis reveals that the studied succession contains mainly gas-prone type III kerogen.The Spore Coloration Index(SCI)alongside with the Rock-Eval pyrolysis results(low values of HI and TOC)proves that these rock units locally produced natural gas during the time under consideration.展开更多
Lower Cretaceous Shurijeh–Shatlyk Formations host some of the main reservoirs in the Kopeh Dagh-Amu Darya Basin.Exploration in this area so far has focused on the development of structural traps, but recognition of s...Lower Cretaceous Shurijeh–Shatlyk Formations host some of the main reservoirs in the Kopeh Dagh-Amu Darya Basin.Exploration in this area so far has focused on the development of structural traps, but recognition of stratigraphic traps in this area is of increasing importance. Integration of 3D seismic data with borehole data from thirteen wells and five outcrop sections was used to identify potential reservoir intervals and survey the hydrocarbon trap types in the East Kopeh Dagh Foldbelt(NE Iran). Analyses of horizontal slices indicated that the lower Shurijeh was deposited in a braided fluvial system.Generally, three types of channel were identified in the lower Shurijeh Formation: type 1, which is low-sinuosity channels interpreted to be filled with non-reservoir fine-grained facies;type 2, which is a moderately sinuous sand-filled channel with good prospectively;and type 3, which is narrow, high sinuosity channel filled with fine-grained sediments. Results indicate that upper Shurijeh–Shatlyk Formations were deposited in fluvial to delta and shallow marine environments. The identified delta forms the second reservoir zone in the Khangiran Field. Study of the stratigraphic aspects of the Shurijeh succession indicates that both lower and upper Shurijeh reservoirs are stratigraphic reservoir traps that improved during folding.展开更多
The biostratigraphy of calcareous nannofossils of the Cretaceous is investigated in the boundary between Abderaz and Kalat Formations through the record of species richness, diversity and distribution patterns in the ...The biostratigraphy of calcareous nannofossils of the Cretaceous is investigated in the boundary between Abderaz and Kalat Formations through the record of species richness, diversity and distribution patterns in the west Kopet-Dagh region. The Kalat Formation comprising of coarse-grained detritus limestone with subordinate sandstone intercalations and the Abderaz Formation mainly consists of limestone, Shale and Limy marl. Nannofossils of this boundary in each of studied sections are listed and figured. 21 species in?Ghalehzoo section, 29 species in Sheikh section and 19 species in Jozak section have been determined. Boistratigraphy based on calcareous nannofossil allow the identification of nannofossil standard zones CC21 and CC26 in all of sections, According to these zones in all of sections, the age of the studied thickness is Early Late Campanian-Late Late Maastrichtian in these sections.展开更多
This is a field report on a comprehensive study of the Atamir Formation from the engineering geology perspective using the related indices. The Atamir Formation of the Cretaceous Period, which has outcropped in the fo...This is a field report on a comprehensive study of the Atamir Formation from the engineering geology perspective using the related indices. The Atamir Formation of the Cretaceous Period, which has outcropped in the form of thick frequencies of grey-knotted sandstone and black shales, is situated in the Kope Dagh zone. A survey of discontinuities together with bedding was carried out to study slope stability. The layers have a general east-west trend with a gentle slope towards the south. Because of the tectonic and stratigraphic differences, and with the purpose of facilitating surveys related to joint study of the outcrop, the formation in the study region was divided into three units. The lower unit is made of shale, the middle of sandstone, and the upper of marlstone. All three units were studied from the perspective of geomechanical classification, rock mass indices, geological strength, geomechanical indices, and wedge instability analysis under dry and wet conditions, and the results were investigated in the form of various images and figures. The Dips software was used to display the rose diagram and stereographic projection of each unit, the Swedge software to analyze instability of the wedges, and the Roctab software to analyze the geomechanical parameters and present the outputs along with the description of each unit.展开更多
In this study, Abderaz Formation at six stratigraphical sections, in east and center of the Kopeh-Dagh sedimentary basin, has been investigated, based on biserial planktonic foraminifera. Totally, 831 samples, with 3 ...In this study, Abderaz Formation at six stratigraphical sections, in east and center of the Kopeh-Dagh sedimentary basin, has been investigated, based on biserial planktonic foraminifera. Totally, 831 samples, with 3 meter distance, were gathered from a sequence with 2800 meter thickness. Also 4 genera and 17 species of biserial planktonic foraminifera have been identified and two biozones and two subzones recognized. Based on obtained data, the age of Early Turonian-Earliest Campanian for the Padeha, Abderaz village and Shorab sections, Midle Turonian-Earliest Campanian for type section, Early Turonian-Late Santonian for Qarehso section and Early Turonian-Earliest Santonian for Hajgelichkhan section were determined. The least amount of plank-tonic foraminifera was identified at Hajgelichkhan, while the maximum amount recognized at Qarehso section.展开更多
This paper discusses the biostratigraphy and palaeoecology of calcareous nannofossils of the uppermost Mozduran Formation in the Jozak section in west Kopet-Dagh basin. The Mozduran Formation consists of white to grey...This paper discusses the biostratigraphy and palaeoecology of calcareous nannofossils of the uppermost Mozduran Formation in the Jozak section in west Kopet-Dagh basin. The Mozduran Formation consists of white to grey Limestone. In the studied sections, samples are taken and prepared with smear slides. In the Jozak section, 17 species have been determined. Based on nannoplanktons and as a result of biostratigraphy studies, the nannofossil standard zones (CC4) are identified. According to this zone, the age of the studied thickness is Early Hauterivian in this section in west Kopet-Dagh basin. The presence of warm water indicators (Nannoconus, Watznaueria, Lithraphidites) suggests warm surface water conditions in the studied thickness. In the Jozak section based on Nannoconus spp., low fertility conditions are suggested. The studied area is deposited in low to middle latitudes and shallow marine environments.展开更多
The main purpose of this paper is the sequence stratigraphy and biostratigraphy of lower Tertiary sediments on the base of larger benthic foraminifera in northeast of Iran (Chehel-Kaman Formation). This formation main...The main purpose of this paper is the sequence stratigraphy and biostratigraphy of lower Tertiary sediments on the base of larger benthic foraminifera in northeast of Iran (Chehel-Kaman Formation). This formation mainly consists of Limestone, dolomite and interbeds of sand, shale and evaporate sediments. Petrographical studies indicate that these sediments may have been deposited on a shallow carbonate platform ramp and consist of 4 carbonate lithofacies (15 subfacies). These lithofacies may have been deposited in open marine, shoal, lagoon and tidal flat environmental conditions. Sequence stratigraphy analysis led to identification of 4 third-order depositional sequences, bounded by type 2 (within the top of the underlying Pestehleigh Formation) and type 1 sequence boundaries (paleosol). Interpreted sea level curve in this basin can be relatively correlated with global curves during Paleocene time and a with a sea-level fall occurred in the latest Paleocene, followed by a rise in the earliest Eocene. Biostratigraphy study led to the identification of 32 larger benthic Foraminifera genera. The Paleocene/Eocene boundary has been probably recorded as a thin red paleosol horizon (~10 - 15 cm).展开更多
Ab-deraz Formation is one of the Lithostratigraphic units of upper cretaceous (Middle Touronian-Santonian) in Kopet-Dagh sedimentary basin, located in northeastern Iran. The aims of this study are separating sequence ...Ab-deraz Formation is one of the Lithostratigraphic units of upper cretaceous (Middle Touronian-Santonian) in Kopet-Dagh sedimentary basin, located in northeastern Iran. The aims of this study are separating sequence units and determining sea level Fluctuation by using palynological factors and comparison via magnetic susceptibility which is used for the first time in Ab-deraz Formation. Assuming the average MS magnitude as the proxy for mean sea level changes, positive Magnetic Susceptibility (MS) values were considered to present sea level falls and negative values for sea level rises. Based on these data a curve showing water level fluctuations throughout the stratigraphic column was prepared which shows a general trend of regression from base to the top of the formation. To test accuracy of this method, magnetic susceptibility results were compared with those gained from palynology and palynofacies studies. Based on the changes in palynological factors (the terrestrial/marine particles ratio, C/PPC ratio, diversity and abundance of dinoflagellate), palynofacies, for separate sequences, three sequences of the third type with four sequence boundaries, (3 boundaries of the type II and one boundary of the type I) were differentiated, confirming the results gained from magnetic susceptibility method.展开更多
A structural-sediment zone of Kopet Dagh is one of the geological units. The southern Kopet Dagh zone is limited to Binalood and the northern limit is with the Turan plateau fault and is created as sediment (Trough) i...A structural-sediment zone of Kopet Dagh is one of the geological units. The southern Kopet Dagh zone is limited to Binalood and the northern limit is with the Turan plateau fault and is created as sediment (Trough) in the late Triassic. The main fault zones are divided into two groups of foundation faults and overthrust. Kopet Dagh is a giant gas field between Turkmenistan, Iran and Afghanistan. Most areas of the region have a temperate climate so cold. From the middle Cambrian to the present, five phases of orogeny have occurred in the region. The geographic location of the study area is 37°43'03"N latitude and 55°35'47"E. In terms of stratigraphic formations in the Cretaceous period, Kopet Dagh area, respectively, is from old to new, including: Shurijeh, Zard, Tiregan, Sar Cheshmeh, Sanganeh, Aitamir, Abderaz, Abtalkh, Neyzar and Kalat. Abtalkh formation is one of the most important rock units in the late Cretaceous in the Kopet Dagh Basin. Abtalkh formation is 489 m and its stratigraphic units are 80 meters of dark grayshale, 20 km dark grayshale with calcareous layers with Inoseramus, 50 m gray marl tend to bluish with Siliceous limestone interlayers, 19 meters of gray-blueshale, 320 meters of light gray shale withthinlayer limestone interlayers. To take pictures of the samples, 100× objective lens and digital camera were used. In the course of this study, the lower part of Abtalkh formation was in Itamir cutting of the study and 9 genera were identified. Recognized calcareous Nannofossil had diversity and abundance. In general, in the greater thickness of the study, samples have moderate preservation. In some cases, the impact of dissolution phenomenon was so great that the main part of the species were corroded. Paying attention to the range of the rise and fall of index species and fossil assemblages, 4 biozones were identified for cutting according to the zones (CC18-CC21) of Sysyngzoning, 1977.展开更多
Atrak River region, northeast Iran is a quaternary tectonically active region. There are many geologic structures that they are formed by the collision of the Arabian and Eurasian plates. This area has extended from n...Atrak River region, northeast Iran is a quaternary tectonically active region. There are many geologic structures that they are formed by the collision of the Arabian and Eurasian plates. This area has extended from north east Iran to the of kope dagh zone. The study area is Atrak river basin and it has been divided to 56 Sub-basin for calculation of 6 geomorphic indices. Finally, this region was classified in 4 relative tectonic activity classes.展开更多
This study is the micropaleontological investigation of the Chehel-Kaman Formation of Paleocene age from Kopet-Dagh basin, NE of Iran. Thirty three species of diagnostic benthic foraminifers belonging to genera?Miscel...This study is the micropaleontological investigation of the Chehel-Kaman Formation of Paleocene age from Kopet-Dagh basin, NE of Iran. Thirty three species of diagnostic benthic foraminifers belonging to genera?Miscellanea,Operculina,?Lockhartia,?Rotalia,?Akbarina,?Pseudocuvillerina,?Smoutina,Davisina,?Idalina,?Valvulina,?Laffitteina,?and?Ranikothalia?are recorded based on detailed petrographic analysis. The rocks are entirely shallow marine in rigin with biotic assemblages confirming Chehel-Kaman Limestone of the Paleocene age. The analyses of benthic foraminifers suggest that the deposition of the Paleogene sequence occurs in warm and shallow marine environments. In this paper?Ranikothalia sindensis?partial zone was reported in association withMiscellanea miscella,?M. juliettae?and?M. yvettae.展开更多
In this research, the Turonian-early Campanian sedimentary succession of the Abderaz Formation with 510 mthick (comprising: light grey shale and marls) was studied in the type section in eastern Kopeh-Dagh basin. The ...In this research, the Turonian-early Campanian sedimentary succession of the Abderaz Formation with 510 mthick (comprising: light grey shale and marls) was studied in the type section in eastern Kopeh-Dagh basin. The statistical analysis of the morphotype groups of the identified planktonic foraminifers shows that most of them are shallow water forms (SWF) and deep water forms (DWF). The high planktonic to benthic ratio indicates particular oligotrophic conditions and sedimentation in relatively deeper zones of a marine environment. The salinity of sea water during Coniacian was in the minimum level, whereas it reached maximum in Coniacian-Santonian boundary. Comparing Planktonic assemblages from the study formation with those from the Cretaceous biogeographical provinces reflects a close relationship between the identified species and the planktonic forms of the Tethyan provinces.展开更多
A structural zone of Dagh Kopet as sediment (Trough) has created in the late Triassic. There are two different views of Dagh Kopet zone: A) Eurasian theory;B) Gondwana theory. The main fault zones are divided into two...A structural zone of Dagh Kopet as sediment (Trough) has created in the late Triassic. There are two different views of Dagh Kopet zone: A) Eurasian theory;B) Gondwana theory. The main fault zones are divided into two groups of foundation faults and overthrust. Abtalkh formation is one of the most important Late Cretaceous rock units in the Kopet Dagh sediment Basin and the geographic location of the study area is "03'43°37 north latitude and "47'35°55 the east. The calcareous nannoplanktons are the first links in the food chain and are the main producers in the seas and oceans. The calcareous Nannoplankton is found in fine sediments such as shale and marl and for study and examination;the presence of trace amounts of sample is enough. The calcareous Lannoplankton is used to identify and introduce Nannofossils of Abtalkh in the bottom of the cut, to determine biozones available at the cutting zone and comparing it with the world standard, to determine their age. In the study section, Nannofossil is in glauconitic sandstone, conglomerate, siltstone, marl, shale, limestone, clay, marl and clay marl and Chuck. Their small size makes that a very small amount of samples are sufficient for the study. The most important method for sample preparation in this study is a smear slide method. In laboratory studies and identification of Nannofossil and counting them, the optical microscope and the object lens 50* and 100* are used. To take pictures of samples, 100× objective lens and digital camera were used. In the course of this study, for the lower part of Abtalkh, Aytamir cutting was studied and 12 genera were identified. The calcareous Nannofossils were recognized and have relatively good diversity and abundance. In general, the greater thickness of the study samples had an average preservation. In some cases, the impact of dissolution was so great that the wall or part of the main sections of the species was corroded.展开更多
基金the National Iranian Oil Company (NIOC) and the University of Tehran for their support
文摘The lower Cretaceous rock units of the Koppeh-Dagh Basin of northeastern Iran were investigated here in terms of biostratigraphy,depositional setting and geochemical analyses to find out if they,alike other parts of the world,are rich in petroleum.For this purpose,a stratigraphic framework is established using calcareous nannofossil and palynological elements.A nannoplankton zonation based on which subzones of the zones CC7–CC8 of Sissingh(1977)and their equivalent NC6–NC8 of Roth(1978)was established indicating a Late Barremian–Albian age.Palynological assemblages led us to establish the local palynozone of Odontochitina operculata.A dominantly marginal basin to a transitional zone between shelf and basin under a dysoxic–anoxic condition with low to moderate sedimentation rates coincided with a gradual sea level rise was introduced as the environment of deposition for the strata via interpretation of the palynological parameters and quantitative palynology.The obtained data from Rock-Eval pyrolysis in compilation with palynofacies analysis reveals that the studied succession contains mainly gas-prone type III kerogen.The Spore Coloration Index(SCI)alongside with the Rock-Eval pyrolysis results(low values of HI and TOC)proves that these rock units locally produced natural gas during the time under consideration.
基金the NIOC Exploration Directorate for supporting the projectthe Ferdowsi University of Mashhad for supporting this project(Research Project Code:3/27868)
文摘Lower Cretaceous Shurijeh–Shatlyk Formations host some of the main reservoirs in the Kopeh Dagh-Amu Darya Basin.Exploration in this area so far has focused on the development of structural traps, but recognition of stratigraphic traps in this area is of increasing importance. Integration of 3D seismic data with borehole data from thirteen wells and five outcrop sections was used to identify potential reservoir intervals and survey the hydrocarbon trap types in the East Kopeh Dagh Foldbelt(NE Iran). Analyses of horizontal slices indicated that the lower Shurijeh was deposited in a braided fluvial system.Generally, three types of channel were identified in the lower Shurijeh Formation: type 1, which is low-sinuosity channels interpreted to be filled with non-reservoir fine-grained facies;type 2, which is a moderately sinuous sand-filled channel with good prospectively;and type 3, which is narrow, high sinuosity channel filled with fine-grained sediments. Results indicate that upper Shurijeh–Shatlyk Formations were deposited in fluvial to delta and shallow marine environments. The identified delta forms the second reservoir zone in the Khangiran Field. Study of the stratigraphic aspects of the Shurijeh succession indicates that both lower and upper Shurijeh reservoirs are stratigraphic reservoir traps that improved during folding.
文摘The biostratigraphy of calcareous nannofossils of the Cretaceous is investigated in the boundary between Abderaz and Kalat Formations through the record of species richness, diversity and distribution patterns in the west Kopet-Dagh region. The Kalat Formation comprising of coarse-grained detritus limestone with subordinate sandstone intercalations and the Abderaz Formation mainly consists of limestone, Shale and Limy marl. Nannofossils of this boundary in each of studied sections are listed and figured. 21 species in?Ghalehzoo section, 29 species in Sheikh section and 19 species in Jozak section have been determined. Boistratigraphy based on calcareous nannofossil allow the identification of nannofossil standard zones CC21 and CC26 in all of sections, According to these zones in all of sections, the age of the studied thickness is Early Late Campanian-Late Late Maastrichtian in these sections.
文摘This is a field report on a comprehensive study of the Atamir Formation from the engineering geology perspective using the related indices. The Atamir Formation of the Cretaceous Period, which has outcropped in the form of thick frequencies of grey-knotted sandstone and black shales, is situated in the Kope Dagh zone. A survey of discontinuities together with bedding was carried out to study slope stability. The layers have a general east-west trend with a gentle slope towards the south. Because of the tectonic and stratigraphic differences, and with the purpose of facilitating surveys related to joint study of the outcrop, the formation in the study region was divided into three units. The lower unit is made of shale, the middle of sandstone, and the upper of marlstone. All three units were studied from the perspective of geomechanical classification, rock mass indices, geological strength, geomechanical indices, and wedge instability analysis under dry and wet conditions, and the results were investigated in the form of various images and figures. The Dips software was used to display the rose diagram and stereographic projection of each unit, the Swedge software to analyze instability of the wedges, and the Roctab software to analyze the geomechanical parameters and present the outputs along with the description of each unit.
文摘In this study, Abderaz Formation at six stratigraphical sections, in east and center of the Kopeh-Dagh sedimentary basin, has been investigated, based on biserial planktonic foraminifera. Totally, 831 samples, with 3 meter distance, were gathered from a sequence with 2800 meter thickness. Also 4 genera and 17 species of biserial planktonic foraminifera have been identified and two biozones and two subzones recognized. Based on obtained data, the age of Early Turonian-Earliest Campanian for the Padeha, Abderaz village and Shorab sections, Midle Turonian-Earliest Campanian for type section, Early Turonian-Late Santonian for Qarehso section and Early Turonian-Earliest Santonian for Hajgelichkhan section were determined. The least amount of plank-tonic foraminifera was identified at Hajgelichkhan, while the maximum amount recognized at Qarehso section.
文摘This paper discusses the biostratigraphy and palaeoecology of calcareous nannofossils of the uppermost Mozduran Formation in the Jozak section in west Kopet-Dagh basin. The Mozduran Formation consists of white to grey Limestone. In the studied sections, samples are taken and prepared with smear slides. In the Jozak section, 17 species have been determined. Based on nannoplanktons and as a result of biostratigraphy studies, the nannofossil standard zones (CC4) are identified. According to this zone, the age of the studied thickness is Early Hauterivian in this section in west Kopet-Dagh basin. The presence of warm water indicators (Nannoconus, Watznaueria, Lithraphidites) suggests warm surface water conditions in the studied thickness. In the Jozak section based on Nannoconus spp., low fertility conditions are suggested. The studied area is deposited in low to middle latitudes and shallow marine environments.
文摘The main purpose of this paper is the sequence stratigraphy and biostratigraphy of lower Tertiary sediments on the base of larger benthic foraminifera in northeast of Iran (Chehel-Kaman Formation). This formation mainly consists of Limestone, dolomite and interbeds of sand, shale and evaporate sediments. Petrographical studies indicate that these sediments may have been deposited on a shallow carbonate platform ramp and consist of 4 carbonate lithofacies (15 subfacies). These lithofacies may have been deposited in open marine, shoal, lagoon and tidal flat environmental conditions. Sequence stratigraphy analysis led to identification of 4 third-order depositional sequences, bounded by type 2 (within the top of the underlying Pestehleigh Formation) and type 1 sequence boundaries (paleosol). Interpreted sea level curve in this basin can be relatively correlated with global curves during Paleocene time and a with a sea-level fall occurred in the latest Paleocene, followed by a rise in the earliest Eocene. Biostratigraphy study led to the identification of 32 larger benthic Foraminifera genera. The Paleocene/Eocene boundary has been probably recorded as a thin red paleosol horizon (~10 - 15 cm).
文摘Ab-deraz Formation is one of the Lithostratigraphic units of upper cretaceous (Middle Touronian-Santonian) in Kopet-Dagh sedimentary basin, located in northeastern Iran. The aims of this study are separating sequence units and determining sea level Fluctuation by using palynological factors and comparison via magnetic susceptibility which is used for the first time in Ab-deraz Formation. Assuming the average MS magnitude as the proxy for mean sea level changes, positive Magnetic Susceptibility (MS) values were considered to present sea level falls and negative values for sea level rises. Based on these data a curve showing water level fluctuations throughout the stratigraphic column was prepared which shows a general trend of regression from base to the top of the formation. To test accuracy of this method, magnetic susceptibility results were compared with those gained from palynology and palynofacies studies. Based on the changes in palynological factors (the terrestrial/marine particles ratio, C/PPC ratio, diversity and abundance of dinoflagellate), palynofacies, for separate sequences, three sequences of the third type with four sequence boundaries, (3 boundaries of the type II and one boundary of the type I) were differentiated, confirming the results gained from magnetic susceptibility method.
文摘A structural-sediment zone of Kopet Dagh is one of the geological units. The southern Kopet Dagh zone is limited to Binalood and the northern limit is with the Turan plateau fault and is created as sediment (Trough) in the late Triassic. The main fault zones are divided into two groups of foundation faults and overthrust. Kopet Dagh is a giant gas field between Turkmenistan, Iran and Afghanistan. Most areas of the region have a temperate climate so cold. From the middle Cambrian to the present, five phases of orogeny have occurred in the region. The geographic location of the study area is 37°43'03"N latitude and 55°35'47"E. In terms of stratigraphic formations in the Cretaceous period, Kopet Dagh area, respectively, is from old to new, including: Shurijeh, Zard, Tiregan, Sar Cheshmeh, Sanganeh, Aitamir, Abderaz, Abtalkh, Neyzar and Kalat. Abtalkh formation is one of the most important rock units in the late Cretaceous in the Kopet Dagh Basin. Abtalkh formation is 489 m and its stratigraphic units are 80 meters of dark grayshale, 20 km dark grayshale with calcareous layers with Inoseramus, 50 m gray marl tend to bluish with Siliceous limestone interlayers, 19 meters of gray-blueshale, 320 meters of light gray shale withthinlayer limestone interlayers. To take pictures of the samples, 100× objective lens and digital camera were used. In the course of this study, the lower part of Abtalkh formation was in Itamir cutting of the study and 9 genera were identified. Recognized calcareous Nannofossil had diversity and abundance. In general, in the greater thickness of the study, samples have moderate preservation. In some cases, the impact of dissolution phenomenon was so great that the main part of the species were corroded. Paying attention to the range of the rise and fall of index species and fossil assemblages, 4 biozones were identified for cutting according to the zones (CC18-CC21) of Sysyngzoning, 1977.
文摘Atrak River region, northeast Iran is a quaternary tectonically active region. There are many geologic structures that they are formed by the collision of the Arabian and Eurasian plates. This area has extended from north east Iran to the of kope dagh zone. The study area is Atrak river basin and it has been divided to 56 Sub-basin for calculation of 6 geomorphic indices. Finally, this region was classified in 4 relative tectonic activity classes.
文摘This study is the micropaleontological investigation of the Chehel-Kaman Formation of Paleocene age from Kopet-Dagh basin, NE of Iran. Thirty three species of diagnostic benthic foraminifers belonging to genera?Miscellanea,Operculina,?Lockhartia,?Rotalia,?Akbarina,?Pseudocuvillerina,?Smoutina,Davisina,?Idalina,?Valvulina,?Laffitteina,?and?Ranikothalia?are recorded based on detailed petrographic analysis. The rocks are entirely shallow marine in rigin with biotic assemblages confirming Chehel-Kaman Limestone of the Paleocene age. The analyses of benthic foraminifers suggest that the deposition of the Paleogene sequence occurs in warm and shallow marine environments. In this paper?Ranikothalia sindensis?partial zone was reported in association withMiscellanea miscella,?M. juliettae?and?M. yvettae.
文摘In this research, the Turonian-early Campanian sedimentary succession of the Abderaz Formation with 510 mthick (comprising: light grey shale and marls) was studied in the type section in eastern Kopeh-Dagh basin. The statistical analysis of the morphotype groups of the identified planktonic foraminifers shows that most of them are shallow water forms (SWF) and deep water forms (DWF). The high planktonic to benthic ratio indicates particular oligotrophic conditions and sedimentation in relatively deeper zones of a marine environment. The salinity of sea water during Coniacian was in the minimum level, whereas it reached maximum in Coniacian-Santonian boundary. Comparing Planktonic assemblages from the study formation with those from the Cretaceous biogeographical provinces reflects a close relationship between the identified species and the planktonic forms of the Tethyan provinces.
文摘A structural zone of Dagh Kopet as sediment (Trough) has created in the late Triassic. There are two different views of Dagh Kopet zone: A) Eurasian theory;B) Gondwana theory. The main fault zones are divided into two groups of foundation faults and overthrust. Abtalkh formation is one of the most important Late Cretaceous rock units in the Kopet Dagh sediment Basin and the geographic location of the study area is "03'43°37 north latitude and "47'35°55 the east. The calcareous nannoplanktons are the first links in the food chain and are the main producers in the seas and oceans. The calcareous Nannoplankton is found in fine sediments such as shale and marl and for study and examination;the presence of trace amounts of sample is enough. The calcareous Lannoplankton is used to identify and introduce Nannofossils of Abtalkh in the bottom of the cut, to determine biozones available at the cutting zone and comparing it with the world standard, to determine their age. In the study section, Nannofossil is in glauconitic sandstone, conglomerate, siltstone, marl, shale, limestone, clay, marl and clay marl and Chuck. Their small size makes that a very small amount of samples are sufficient for the study. The most important method for sample preparation in this study is a smear slide method. In laboratory studies and identification of Nannofossil and counting them, the optical microscope and the object lens 50* and 100* are used. To take pictures of samples, 100× objective lens and digital camera were used. In the course of this study, for the lower part of Abtalkh, Aytamir cutting was studied and 12 genera were identified. The calcareous Nannofossils were recognized and have relatively good diversity and abundance. In general, the greater thickness of the study samples had an average preservation. In some cases, the impact of dissolution was so great that the wall or part of the main sections of the species was corroded.
