Stratigraphy and Palaeontology
Parisa Mohammadi; Abbas Ghaderi; Ali Reza Ashouri
Abstract
The Julfa region in East Azerbaijan Province exhibits one of the best continuous marine sedimentary successions across the Permian to Triassic boundary. The present study is focused on the brachiopod contents of the Julfa beds in Qareh-Goz section (41.5 m thickness) in the south of Julfa. This study ...
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The Julfa region in East Azerbaijan Province exhibits one of the best continuous marine sedimentary successions across the Permian to Triassic boundary. The present study is focused on the brachiopod contents of the Julfa beds in Qareh-Goz section (41.5 m thickness) in the south of Julfa. This study is led to the determination of 11 genera and 21 species of the orders Athyridida, Orthotetida, Orthida, Productida, Spiriferida, and Terebratulida, all representing the Cathaysian bioprovince for this area in the Western Paleotethys. Accordingly, four Wuchiapingian biozones, including Araxilevis intermedius Zone, Araxilevis intermedius-Permophricodothyris ovata Interval zone, Permophricodothyris ovata Zone, and Transcaucasathyris araxensis Zone, have been detected. These biozones correlate well through the other stratigraphic sections of the Julfa area in the Ali Bashi and Zal Mountains, Dorasham section in the Transcaucasia, Hembast Formation in the Abadeh area, and Nesen Formation in the central Alborz, approving the potential of these brachiopods in biocorrelation at a regional scale in the Late Permian.
Stratigraphy and Palaeontology
Abbas Ghaderi; Mahdi Badpa; Ali Reza Ashouri
Abstract
To study of Permian corals at the northwest of Iran, Ali-Bashi stratigraphic section was selected and sampled. After microscopic studies of several longitudinal, transverse, and serial sections were obtained from more than 180 coral fossils, 12 species belonging to 6 genera of rogues and tabula corals ...
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To study of Permian corals at the northwest of Iran, Ali-Bashi stratigraphic section was selected and sampled. After microscopic studies of several longitudinal, transverse, and serial sections were obtained from more than 180 coral fossils, 12 species belonging to 6 genera of rogues and tabula corals were determined. The Permian succession of the Julfa area is the dominion of two types of coral fauna. Waagenophyllidae fauna that is the territory of the colonial coral forms comprises typically Tethyan indicators such as Ipciphyllum and Waagenophyllum with the age of Middle?- Late Permian. Cyathaxonia fauna, Late Permian in age, include terminal phylogenetic representatives of the rugose corals, mostly composed of solitary one Pentaphyllum. This genus is persistent till the vicinity of the extinction horizon at the near end Permian in the Ali Bashi Formation topmost horizon. Also, the last standing tabula coral before the Late Permian extinction in the Julfa region is the genus Protomichelinia. The Permian coral fauna of the NW Iran finely corresponds to those of the Abadeh region in Central Iran and Transcaucasus. The Waagenophyllidae forms are the same as South China fauna, whereas the Cyathaxonia ones reveal a high endemism in the Late Permian of NW Iran.
Akbar Jabbari; Asghar Dolati; Alireza Shahidi; Amin Behrooz
Abstract
Abstract: The Alborz Mountain range is formed by collision between the Central Iran and Eurasia plates, since Late Triassic. Facieses studies on the Alborz and Central Iran indicate sedimentation in shelf and epicontinental shelf in passive margin of Gondwana during Paleozoic Era. This study represents ...
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Abstract: The Alborz Mountain range is formed by collision between the Central Iran and Eurasia plates, since Late Triassic. Facieses studies on the Alborz and Central Iran indicate sedimentation in shelf and epicontinental shelf in passive margin of Gondwana during Paleozoic Era. This study represents direction and paleostress analysis of the Central Alborz based on geometry and kinematics of faults; i.e. strike, dip, slicken line orientation and movement directions for Carboniferous and Permian Periods. Since many tectonic events occur after the Paleozoic Era in the Alborz Mountain range so just growth faults, active during sedimentation, which were not reactivated by later events were used for paleostress analysis. In total 15 stations, including 148 fault data are measured along the Tehran-Chalus road from Carboniferous and Permian outcrops. The data were rotated to the first position based on fold axes, when the layers were horizontal. FSA software (Fault Slip Analysis) was used to calculate orientations of principal stress directions. Primary results indicate a proximately North-South extension in Carboniferous and Permian Periods. Iran and adjacent area, rotated along vertical axis during its movements from Gondwana, in South, to Eurasia, in north, that based on the plate rotation the extension direction for Permian and Carboniferous Periods are NE-SW and ENE-WSW, respectively.
Sedimentology
Afshin Zohdi
Abstract
In this study, for the first time stratigraphy and depositional history of the Routeh Formation have been evaluated in west of Zanjan (Agh-Bolagh section). These deposits with thickness of 102m consist of limestone, dolomitic limestone with the less frequency of thin-bedded calcareous shales. This sedimentary ...
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In this study, for the first time stratigraphy and depositional history of the Routeh Formation have been evaluated in west of Zanjan (Agh-Bolagh section). These deposits with thickness of 102m consist of limestone, dolomitic limestone with the less frequency of thin-bedded calcareous shales. This sedimentary sequence with an unconformity overlies the quartz-bearing sandstones of Doroud Formation and is overlain by a laterite-bauxite horizon below the vermiculate-bearing limestone of Elika Formation. The main components of Routeh Formation contain different kinds of algae, small benthic foraminifera and with a less frequency echinoderm and brachiopod debris. Based on filed and laboratory studied eight sedimentary facies have been distinguished into the Routeh Formation. These facies due to the different types of allochems, texture and fossil content display a shallow-water marine environment during deposition of the Routeh Formation located at Palaeotethys passive southern margin. The absence of re-sedimented deposits like: turbidites, presence of micrite at the most of facies, lack of continues reefal facies and gradual facies change indicate that the Routeh Formation possibly were deposited in a ramp carbonate platform. Due to great diversity and abundance of algae and benthic foraminifera, this carbonate ramp is referred to as an “algae and foram-dominated carbonate ramp system”. Field observations, facies analyses and sequence stratigraphy studied led to the identification of one-third order depositional sequence into the Routeh Formation. This depositional sequence separated by type-1 sequence boundaries at below with quartz-bearing sandstones of Doroud Formation and at the top with laterite-bauxite horizon between Routeh and Elika formations
F. Rostami; M. Delavari; S. Amini; A. Dolati
Abstract
The Permian volcanic rocks of Central Alborz (northeast of Baladeh- Siahbisheh) crop out between Ruteh and Nesen Formations. The volcanic rocks are predominantly basaltic and plagioclase- phyric. Ferromagnesian minerals such as clinopyroxene and olivine are not modally abundant and sometimes are totally ...
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The Permian volcanic rocks of Central Alborz (northeast of Baladeh- Siahbisheh) crop out between Ruteh and Nesen Formations. The volcanic rocks are predominantly basaltic and plagioclase- phyric. Ferromagnesian minerals such as clinopyroxene and olivine are not modally abundant and sometimes are totally altered. Based on microprobe data, clinopyroxene and plagioclase are diopside (En34.2-36.4 Wo43.1-47.2 Fs14.9-18.1) and labradorite (50<An%<55), respectively. Clinopyroxene and plagioclase geothermobarometric calculations shows the temperature and pressure ranges of 1050 to 1200 °C and 2 contents (4.94- 7.24 wt. %). Clinopyroxene chemical data display that the parent melt was alkaline basalt, generated in a within plate setting. On the basis of our findings it can be stated that, Central Alborz was a continental passive margin in middle- late Permian at south of Paleo-Tethys and its magmatism was likely triggered by late Paleozoic extensional tectonism of northern margin of Gondwana during the early stages of Neo-Tethyan development.
M Medadi; H Mosaddegh; S.H Aleali; M.R Majidifard
Abstract
Some paleobiodiversity indices such as total diversity, stand diversity, origination and extinction rates of Permian (Yakhtashian- Dzhulfian) small foraminifera were analyzed based from an outcrop in Abe-Garm area, Gazvin. Some important bizones that recognized by Taraz (1969), Taraz et al. ...
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Some paleobiodiversity indices such as total diversity, stand diversity, origination and extinction rates of Permian (Yakhtashian- Dzhulfian) small foraminifera were analyzed based from an outcrop in Abe-Garm area, Gazvin. Some important bizones that recognized by Taraz (1969), Taraz et al. (1981), Kobayashi (1997), Shabanian (2010), Stiger (1966), Davydov et al. (1996) were used for separation of stages, and biodiversity indices were calculated based on Foote (2000). The investigations are resulted in recognition of Two trends:1: Origination rate decrease rapidly from Yakhtashian to Murgabian and,2: two rapid increase in the extinction rate are recorded in Midian and Dzhulfian, the first comparable with End-Guadalopian mass extinction and the latter probably related to environmental condition.
R Shabanian; N Farajnezhad
Abstract
Permian deposits crop out in the North East QarehZiaaeddin (Illanlu section) consisting Dorud, Ruteh, Nesen and Elli Bashi formation respectively. In this section, the Ruteh Formation composes about 751.3m of dark to grey, medium to massive limestone. The Nesen Formation contains approximately 627.3m ...
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Permian deposits crop out in the North East QarehZiaaeddin (Illanlu section) consisting Dorud, Ruteh, Nesen and Elli Bashi formation respectively. In this section, the Ruteh Formation composes about 751.3m of dark to grey, medium to massive limestone. The Nesen Formation contains approximately 627.3m of shaly limestone, shale and marl and finally the Elli Bashi formation contains about 22.7m grey thin nodular limestone, Red limestone and colored shale. The lower boundary of marine sequence is marked disconformably by Dorud Formation and upper boundary is conformable and continuous with Early and middle Elika Formation. On the basis of stratigraphical distribution of microfossils chiefly foraminifera five Assemblage biozoneswere distinguished includingTetrataxis-Globivalvulina-Nankinella Assemblage Biozone (Kubergandian), Langella-Geinitzina Assemblage Biozone (Early to Middle Murghabian), Paraglobivalvulina-Pachyphloia Assemblage Biozone (Late Murghabian to Midian), Codonofusiella-Palaeotextolaria Assemblage Biozone(Midian), Frondina-Hemigordius-Cribrogenerina Assemblage Biozone (Dzhulfian). The identified microfossils suggest Kubergandian to Dorashamian ages (Middle to Late Permian) for carbonate sequences of Permian at the study area. On the basis of lithological changes 15 lithozone were also recognized.With regards to lithological and paleontological characteristics and sequence thickness of marine sequence the Illanlu section is proposed as standard section for Middle and Late Permian stages.
N Haghighat; P Mansuri
Abstract
The Permian deposits in the Sibestan section located at 65 km. northwest of Tehran and consist of 3 formal Formations. In order from lower to upper: 1- Dorud Fm. consisting of 205 meters of siliciclastic deposits of early Permian age and according to the lithostratigraphy facies is divided into 10 rock ...
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The Permian deposits in the Sibestan section located at 65 km. northwest of Tehran and consist of 3 formal Formations. In order from lower to upper: 1- Dorud Fm. consisting of 205 meters of siliciclastic deposits of early Permian age and according to the lithostratigraphy facies is divided into 10 rock units. 2- Ruteh Fm. consisting of 178 m. of limestone of Late early Permian (Murghabian) age. It also according to the lithostratigraphy facies is divided into 5 rock units. 3- Nessen Fm. consisting of 54 m. of limestone, shale and sandstone of lower Julfian age. This Formation is also divided into 8 lithologic units. The Permian sedimentary deposits terminates by bauxite-laterite horizon of Julfian equivalent age. This sequence is covered disconformably by 28.10 m. of yellowish gray platy limestone of strata Lower Triassic Elika Fm.
According to the paleontological studies, three biozones of foraminifers in Ruteh and Nessen formations have been identified:
Ruteh Fm.:
1- (Schubertella giraudi-Codonofusiella distincta assemblage zone) of Bolorian?-Kubergandian age.
2- (Cribrigenerina sumatruna- Langella ocarina assemblage zone) of Murghabian age.
Nessen Fm.:
3- (Paraglobivalvulina mira-Ichtyolaria assemblage zone), of Median?- Julfian age.
In addition, 14 species and genus and one subspecies of conodonts have been identified and also 2 conodonts biozones have been recognized in this section which correspond to the international conodonts.
Ruteh Fm.:
1- Sweetognathus whitei biozone (Early Permian).
Elika Fm:
2- Hindeodus parvus-Isarcicella isarcica biozone (Early Triassic).
3- Pachycladina symmetrica-P. oblique assemblage zone (Early Triassic).
M Sadeghi; K Rashidi; R Shabanian
Abstract
Succession of Permian system in Pir-Eshagh stratigraphic section has been mesured totally about 1400 m, which it's base consists mainly of Dorud formation with thickness of about 100 m which in turn has been overlain by Ruteh and Nesen formations with thickness of 1100 and 200 m respectively. Lower boundary ...
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Succession of Permian system in Pir-Eshagh stratigraphic section has been mesured totally about 1400 m, which it's base consists mainly of Dorud formation with thickness of about 100 m which in turn has been overlain by Ruteh and Nesen formations with thickness of 1100 and 200 m respectively. Lower boundary of this succession overlay unconformablyon the Devonian volcanic rocks and the upper parts continuously and concordantly is changed to yellow lamellar limestone, Elika formation that deposited in lower and middle Triassic. For identification of various calcareous genus and species of algae in these sediments,we systematically selected 220 thin sections from the lower bound up to the upper bound based on the lithological changes perpendicular to the strike of layers. In this study, we identified 7 genus and 9 types of dasycladaceae green algae Mizzia sp., Mizzia velebitana, Mizzia cornuta,Macroporella cf. nuda, Macroporella sp., Epimastopora sp., Epimastopora symetrica, Paraepimastopora longutuba, Epimastopora likana, Epimastoporella japonica, Tabasoporella tulipaformis, Gyroporella sp., Gyroporella nipponica, and 2 genus and 5 types of gymnocodiacea algae family Permocalculus sp., Permocalculus cf. dikenliderensis, Permocalculus fragilis, Permocalculus plumosus, Permocalculus tenellus, Gymnocodium sp., Gymnocodiumbellerophontis at Ruteh and Nesen formations. Also, Tabasoporella tulipaformis algae belonging to the dasycladaceae family which has been introduced from the Jamal formation, for the first time was identified and reported from the carbonated units in the northwest of Iran.
H. Yarahmadzahi; M. N. Gorgij; S. A. Aghanabati; A. Saeidi
Abstract
The studied section is located west of Tabas (Rahdar Mountion) in the Kalmard Block. The newly named Chili formation, as the first rock unit of the Khan group consist mainly of arenacous limestone, limestone and dolomite and has disconformity contact with underlying lower carboniferous deposits (Padeh ...
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The studied section is located west of Tabas (Rahdar Mountion) in the Kalmard Block. The newly named Chili formation, as the first rock unit of the Khan group consist mainly of arenacous limestone, limestone and dolomite and has disconformity contact with underlying lower carboniferous deposits (Padeh formation) and overlying late Yakhtashian-Early Murgabian (Sartakht formation) bauxite and laterite horizon,in this study 6 genus and 19 species of Fusulinids were recognized which could be grouped in two Biozones. The first biozone correspond to Perigondwania pamirensis Zone belonging to Late Sakmarian. The second one is comparable with Chalaroschwagerina vulgaris Zone of Early Yakhtashian age. The mentioned biozone is fairly comparable with Kalaktash assemblage already reported from Central Pamir,Karakorom, Afghanestan and south Tibet regions.
R. Shabanian
Abstract
The Permian sequences of Aru and Bibishahrbanoo sections comprise the Dorud, Ruteh and Nesen formations respectively. A precise dating of the formations was provided based on the analysis of smaller foraminifers and fusulinid assemblages. The clastic Dorud Formation refered to Asselian and Sakmarian ...
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The Permian sequences of Aru and Bibishahrbanoo sections comprise the Dorud, Ruteh and Nesen formations respectively. A precise dating of the formations was provided based on the analysis of smaller foraminifers and fusulinid assemblages. The clastic Dorud Formation refered to Asselian and Sakmarian stages. The platform limestone of Ruteh Formation corresponds to Kubergandian – Murgabian stages. The Laterite and Bauxite horizon in the studied area attributed to Midian and finally, the uppermost beds of Permian in Bibisharbanoo corresponds to Early Dzhzulfian, based on the proposed of international subcommission on Permian stratigraphy concerning Tethyian stage bourdaries. Biolithic limestones of Ruteh Formation lying transgressively and disconformably on the underlying clastic and continental Dorud Formation with a great hiatus consists of Yachtashian and Bolorian stages. In both stratigraphical sections, thin vermiculate and oolithic limestone of Elika formation belonge to Early to Middle Triassic lying disconformably on the Permian sequence with hiatus. The hiatus between Permian and Triassic in Aru comprise Dzhulfian and Dorashamian stages and in Bibi Shahrbanoo stratigraphical section include Late Dzhulfian and Dorashamian stages. In this study 45 species belonging to 40 genus related to fusulinid families, smaller foraminifers and calcareous algae were recognized.
H. Mosadegh; M. Lankarani
Abstract
The carbonate facies of Permian in Gaduk area (Central Alborz) are dominated by calcareous algae. Study of the facies resulted in recognition of several species of Cyanobacteria, Dasycladacean and Gymnocodiacean green algae and also Phylloid algae. In the studied succession, Phylloid algae are identified ...
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The carbonate facies of Permian in Gaduk area (Central Alborz) are dominated by calcareous algae. Study of the facies resulted in recognition of several species of Cyanobacteria, Dasycladacean and Gymnocodiacean green algae and also Phylloid algae. In the studied succession, Phylloid algae are identified in carbonate shoal facies. Cyanobacteria mostly occurred in tidal to lagoonal facies, as encrusters. Dasycladacean and Gymnocodiacean green algae mostly occurred in inner ramp facies. Gymnocodiaceans were found in deeper parts in comparison to Dasycladaceans. Occurrence of Cyanobacteria in depositional sequences coincides with type-one sequence boundaries. Phylloid algae are identified in the facies related to transgressive surfaces and maximum abundance of Dasycladaceans and Gymnocodiaceans was found around maximum flooding surfaces and in highstand systems tracts. Abundance of the calcareous algae shows an increasing trend from the base to the top of carbonate parasequences. Proliferation of the calcareous algae was found in close relationship to climate warming and ice-house to green-house transition in Permian of Alborz.
R. Shabanian; M. Parvanehne-Nezhad Shirazi; F. Javadinia
Abstract
The detailed stratigraphical and lithological analysis of the Permian sequence in north Marand, NW of Iran at Harzand village has been studied . At this locating the Permian sequence consist of Dorud (82 m..) Surmaq (258 m..) and Julfa (108 m.) formations respectively. The main lithology consist ...
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The detailed stratigraphical and lithological analysis of the Permian sequence in north Marand, NW of Iran at Harzand village has been studied . At this locating the Permian sequence consist of Dorud (82 m..) Surmaq (258 m..) and Julfa (108 m.) formations respectively. The main lithology consist of white to red sandstone, grey to dark, biogenetic limestone , marly limestone and thin bedded limestone. The lower boundary is non conformity, so that the Permian sequence is underlying a thick extrusive igneous rocks and at the top, a sequence of Miocene red clastic deposit covers the Permian sequence with disconformably. In this study 52 foraminiferal species belonging to 37 genus and 8 species of 9 Algal genus were recognized and 4 assemblages biozones in Surmaq and Julfa formations have identified. Based on fossils assemblages , the age of the Surmaq formations is Kubergandian - Murgabian (Middle Permian) and the age of Julfa formation is Middian - Early Dzhufian Stages(Late middle –Early late Permian).
R. Shabanian; D. Vachard
Abstract
Carbonate sediments of Permian age crops out in different parts of Iran. based On the foraminiferal content, they are attributed to Bolorian (?) ,Kubergandian to Dorashamian stages.These biogenetic limestone have plenty of Fusulinaceaa, non-fusulinid smaller foraminifers ...
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Carbonate sediments of Permian age crops out in different parts of Iran. based On the foraminiferal content, they are attributed to Bolorian (?) ,Kubergandian to Dorashamian stages.These biogenetic limestone have plenty of Fusulinaceaa, non-fusulinid smaller foraminifers and algae, and they are a basis for determination of age, establishment of biozonation and paleogeography of Permian based on fusulind content. In some localities,chiefly in the north and northwest of Iran because of the distribution of Fusulinid are very rare paleoecological and paleo environmental factors.Despite these situation, smaller foraminifers, especially uniserial ones have a very important role in carbonate sediment make up, determination of age and reconstruction of paleoenvironment.In this paper, this important and crucial role of uniserial foraminifers is discussed.
R. Shabanian; Kh. Khosrow Tehrani; I. Momeni
Abstract
Various stratigraphical sections of the Permian rocks in the northwest of Iran (Azerbaijan) shows that this sequence consists of Doroud, Ruteh, and Nesen formations in the southern flanks and Doroud, Surmaq , Julfa and Ali-Bashi formations in Zal and Illanlu sections.
The analysis and study of forminifera ...
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Various stratigraphical sections of the Permian rocks in the northwest of Iran (Azerbaijan) shows that this sequence consists of Doroud, Ruteh, and Nesen formations in the southern flanks and Doroud, Surmaq , Julfa and Ali-Bashi formations in Zal and Illanlu sections.
The analysis and study of forminifera assemblages in the carbonate sequence of the area and the comparison of these microfossils with other parts of Iran and neighbouring countries indicate that the age of carbonate units is Kubergandian to Dorashamian in Zal and Illanlu areas and Kubergandian to Djulfian in others sections. Throughout the Azerbaijan, Lower Permian shows a great hiatus.
Field investigation, rock and microfacies studies show many progressive and regressive phases in the Permian sequence of Azerbaijan.
