Stratigraphy and Palaeontology
elahe zarei
Abstract
The Dalichai Formation in Ahvanu section in the north of Damghan city with a thickness of 78 meters consisting of an alternation of bluish-gray marls and limestone, was studied. Based on the presence and stratigraphic distribution of miospore, Klukisporites variegatus and Callialasporites dampieri of ...
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The Dalichai Formation in Ahvanu section in the north of Damghan city with a thickness of 78 meters consisting of an alternation of bluish-gray marls and limestone, was studied. Based on the presence and stratigraphic distribution of miospore, Klukisporites variegatus and Callialasporites dampieri of pollen are identified (Middle Jurassic) and presence of some index dinoflagellate species led to the identification of three biozones in the Dalichai Formation. These include in ascending order, Cribroperidinium crispum Total Range Biozone (late Bajocian), Dichadogonyaulax sellwoodii Interval Biozone (Bathonian - early Callovian), Ctenididinium continuum Interval Biozone (early to middle Callovian). Also, this Formation was divided into two biozone on the basis of Lenticulina varians-Ophtalmidium Assemblage zone and Globigerina bathoniana Taxon range zone. The close similarities of fauna assemblages of Dalichai Formation in this region (eastern Alborz ((dinoflagellate cyst, foraminifera, posidonia and radiolar) with assemblages recorded from different parts of Iran (such as central and eastern, western Alborz and Binalud and south of Iran) and other parts of world (northwest of Europe, and the northwestern Tethys and …) confirm the marine connection and faunal exchange between the mentioned basins during Middle Jurassic.
Stratigraphy and Palaeontology
Zeinab Manouchehri; Tayebeh Mohtat; Seyed Ali Aghanabati; Morteza Khalatbari Jafari; Fatemeh Vakil Baghmisheh
Abstract
The sediments are generally limestone and marl. The lower boundary with the loer red Formation is disconfomity and the upper boundary with the equivalent formatin of Bakhtiari Firmation is paraconformity. The total number of fossils found in this section is 69 species, 72 genera and 46 families. These ...
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The sediments are generally limestone and marl. The lower boundary with the loer red Formation is disconfomity and the upper boundary with the equivalent formatin of Bakhtiari Firmation is paraconformity. The total number of fossils found in this section is 69 species, 72 genera and 46 families. These sediments are formed in an open shelf and under the open sea and lagon environment. The variety and abundance of bentic foraminifer’s forms and the low presence of plagic forms testify to the shallow basin in this section, which is also confirmed by the study of other fossils. One of the Markable features of this section is the presence of Ammonia species, especially Ammonia parkinsonia. This section has a complete sequence of members of Qom Formation. This species are profe of shallow water and continental shelf for this carbonates. This section consist all of members of Qom Formation and based on identified foraminifera comparable to assemblage zone 1 & 2 introduced by Adams & Bourgeois (1967). These zones that inclod: 1-Borealis Melo Group- Meandropsin; 2- Miogypsinoides- Archaias- Valvulinid. Based on index foraminifer's species and their stratigraphic distribution the age of this section is Chatian- Burdigalian (Upper Oligocene-Lower Miocene)
Stratigraphy and Palaeontology
Arash shabanpour Haghighie; Lida Bakhshandeh; Tayebeh Mohtat; Masood Zamanipedram; Seyed hamid Vaziri
Abstract
In this research the Gurpi Formation in the Zagros Basin outcropping in the Dasht-e Arjan section, Shiraz province ,for the purpose of biozonational and Paleobathymetric studies were investigated. The thickness of these sediments is about 130 m and consists of Limestones and Shales.To determine the palaeobathymetry ...
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In this research the Gurpi Formation in the Zagros Basin outcropping in the Dasht-e Arjan section, Shiraz province ,for the purpose of biozonational and Paleobathymetric studies were investigated. The thickness of these sediments is about 130 m and consists of Limestones and Shales.To determine the palaeobathymetry of the Gurpi Formation, Planktonic and benthic foraminifera were investigated . A depth of about 270m to 510m was determined for these sediments based on the ratio of planktonic foraminifera to the total assemblages of foraminifera after omitting infaunal benthic foraminifera (%P*) by using the equation D = e (3.58718+(0.03534 × %P* )).In this study sixty-two species of planktonic foraminifera belonging to eighteen genera were recognised .According to the studied planktonic foraminifera the Upper Cretaceous deposits in this area were divided into nine biozones as following :biozone1- Dicarinella concavata Interval Zone. Biozone2- Dicarinella asymetrica Total Range Zone. Biozone3- Globotruncanita elevata Partial range zone .Biozone4- Globotruncana ventricosa Interval Zone. Biozone5- Radotruncana calcarata Interval zone. Biozone 6- Globotruncanella havanensis Partial Range Zone. Biozone7- Globotruncana aegyptiaca Interval Zone. Biozone 8- Gansserina gansseri Interval Zone. Biozone 9- Contusotruncana contusa Interval ZoneBased on the studied planktonic foraminifera the Early Santonian to Maastrichtian ages were determined for the sediments .
Stratigraphy and Palaeontology
Tayebe Sarbandi Farahani; Mehdi Yazdi; Mahmoud Reza Majidifard
Abstract
This paper focused on the systematic of the benthic foraminifera from the Chaman Bid and Goznawwi sections. At the type locality of the Chaman Bid Formation, consists of alternation of limestone (grainstone to wackstone), argilasious limestone and marl. The age of tha Chaman Bid Formation based on ammonite ...
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This paper focused on the systematic of the benthic foraminifera from the Chaman Bid and Goznawwi sections. At the type locality of the Chaman Bid Formation, consists of alternation of limestone (grainstone to wackstone), argilasious limestone and marl. The age of tha Chaman Bid Formation based on ammonite fauna range from ?Bathonian to late Tithonian. and the age. Near the Azadshar, the Farsian Formation is exposed and consists of fossilferous the soft marl, sandstone, limestone and silt which based on ammonite, age of this sediment considered as Callovian. Two studied sections are bearing well - preserved foraminifera which most belong to Lagenina (most belong to Nodosaridae and Vaginolinidae families) and Rotalina (Epistominidae); total 23 genus and 39 species from Goznawwi and 10 genus and 16 species from Chaman Bid sections. The 28 species of the benthic isolated foraminiferal assemblages are first recorded from Iran. In additional, based on this study, Iranian assemblage of foraminifers at this time are most similar to those of the North of the tetyan releam.
E. Zarei; E. Ghasemi-Nejad; A. Dehbozorgi
Abstract
The Gurpi Formation was studied from different aspects at two sections, Farhadabad and Kavar, in southwest and southeast of Ilam where it is composed of 205 m and 158 m of grey to blue marl and shale beds and occasionally thin beds of argillaceous limestones with two formal members of Seymareh (Lopha) ...
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The Gurpi Formation was studied from different aspects at two sections, Farhadabad and Kavar, in southwest and southeast of Ilam where it is composed of 205 m and 158 m of grey to blue marl and shale beds and occasionally thin beds of argillaceous limestones with two formal members of Seymareh (Lopha) and Emam-Hassan. In order to reconstruct paleoclimate during depositional course of the formation, paleontological and palynological data (ratio of specialist to generalist foraminifera (e.s/e.g) and warm-temperate waters dinocysts and spore and pollen grains) were used statistically. The results show that the Gurpi Formation is mainly deposited in a warm-humid climate with two sharp decreases happening in temperature in early Maastrichtian and Danian.
R. Haftlang; M. Afghah; S. A. Aghanabati; M. Parvaneh Nezhad Shirazi
Abstract
Lithological and biological Sequences of Cretaceous in Bahar section, Located in South Esfahan (147 m. true thickness) include grayish olive green pencil- like shales containing Budantysras Ammonites (Albian) interbedded with limy shales. which are covered by glauconitic Sandy Limestone (Early Turonian) ...
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Lithological and biological Sequences of Cretaceous in Bahar section, Located in South Esfahan (147 m. true thickness) include grayish olive green pencil- like shales containing Budantysras Ammonites (Albian) interbedded with limy shales. which are covered by glauconitic Sandy Limestone (Early Turonian) (with erosional discontinuity). These sandy limestones are wackestone and rarely greenstone, according to Dunham classification. Based on Biozone divisions, this unit is related to Biozone No. 27 presented by Wynd (1965) and it is equivalent to Sarvak Formation in Zagros. Marly limestone and limestone containing Inoceramus bivalve interbedded with marl dating back to Late, Middle Touronian- Late Touronian- Coniacian to Early Santonian are younger equivalents of this section which can be equaled to Surgah Formation. According to Biozone divisions, this unit is equivalent to Biozone No. 28 presented by Wynd (1965) and also based on Dunham classification, the unit is packestone and partly boundstone. The lower Contact of the unit is Concordant and Continuous with glauconitic sandy limestone and its upper Contact is Continuous and Concordant with marl and interbeddings of Limestones dating back to Santonian- Campanian. By comparing Bahar Section with South eastern Lorestan section (Poshte jangal anticline), (Azadbakht, 2015), the following results were obtained: From Litho/bio stratigraphical view, thick to thin-bedded Limestones (Light to dark gray) interbedded with marl in Poshte jangal anticline are Correlated with Inoceramus limestone and marly Limestone interbedded with marl in Bahar Section. They are dated back to EarlyTuronian to Early Campanian.Due to Strong similarity of Lithostratigraphy and biostratigraphy between Bahar section located in Southern Esfahan (Central Iran) and section of Poshte jangal anticline located in Southeast of Lorestan, it can be deducted that a branch of Lorestan Sea has advanced in Turonian- Coniacian times and some parts of Southern Esfahan has been covered by the sea.
B Saberzadeh; K Rashidi; M Vahidinia
Abstract
This paper describes systematic of the foraminifera from Howz-e Khan Member of Nayband Formation in 25km south of the type locality which are exposed in northwest of the Dig-e Rostam area about 300km north of Kerman city and is composed of medium to thick bedded fine-grained limestones containing sponges, ...
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This paper describes systematic of the foraminifera from Howz-e Khan Member of Nayband Formation in 25km south of the type locality which are exposed in northwest of the Dig-e Rostam area about 300km north of Kerman city and is composed of medium to thick bedded fine-grained limestones containing sponges, dasycladales algae, bivalves, corals and partly abundant upper Triassic foraminifera ofNorian-Rhaetian ages which are mainly of aulotortid types. The following foraminifera taxa are described: Auloconuspermodiscoides, Aulotortus friedli, Aulotortus tenuis, Aulotortus tumidus, Aulotortus sinuosus, Duotaxis birmanica, Tetrataxis inflata, Agathammina austroalpina, Miliolipora cuvillieri, Planiinvoluta sp., Ophthalmidium leischneri, Ophthalmidium exiguum, Glomospirella sp., Trochammina alpina, Diplotremina astrofimbriata, Diplotremina subangulata, Duostomina sp., Nodosaria sp1., Nodosaria sp2., Pseudonodosaria sp., Austrocolomia sp., Sigmoilina schaeferae, Reophax tauricus. In this paper relation of foraminifera with reefs and carbonate layerthat are generally typical of low energy, bay or lagoon-type, on shallow carbonate ramps and reef facieshas been studied.
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).
R Shabanian; N Ghanizadeh; M Mohammadi; N Roohi
Abstract
In this study, 60 samples have been studied from Carboniferous deposits of Khames stratigraphical section, 10 Km southeast of Khalkhal. The marine sequence of Khames stratigraphical section is about 163.5 m. thick and consists of gray to black Limestone and dolomitic limestone. The lower boundary of ...
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In this study, 60 samples have been studied from Carboniferous deposits of Khames stratigraphical section, 10 Km southeast of Khalkhal. The marine sequence of Khames stratigraphical section is about 163.5 m. thick and consists of gray to black Limestone and dolomitic limestone. The lower boundary of the under study section marked with yellowish limestones of Cretaceous and dark Sills with Faulted contact. The upper boundary of the Carboniferous strata is covered with Pliocene Polygenetic conglomerate disconformably. The Carboniferous unit studied here has not been named so far, so in this research, we have attempted to identify the stratigraphical position of the mentioned sequence. In this research 30 genera and 25 species of benthic foraminifera were identified similar to those reported from carboniferous strata of Qezelqaleh, Bagher Abad, Mobarak and Sardar formations suggesting a Late Visean to Early Bashkirian age for the Khames Carboniferous marine sequence.
M.H Kazemzadeh; E Ghasemi-Nejad; H Vaziri-Moghaddam
Abstract
The Sarvak Formation in Well AZ 354 of Ahwaz Oil Field attains a thickness of 1712 meters and contains creamy to white and occasionally gray limestone. The recorded foraminifera indicate upper Albian to lower Turonian age for this formation. In order to study paleobathymetry and sea level changes during ...
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The Sarvak Formation in Well AZ 354 of Ahwaz Oil Field attains a thickness of 1712 meters and contains creamy to white and occasionally gray limestone. The recorded foraminifera indicate upper Albian to lower Turonian age for this formation. In order to study paleobathymetry and sea level changes during depositional course of the formation, three common methods were used: in the first method, the absolute number of benthic foraminifera and percentage of Hyaline, Agglutinate and Porcelaneous tests and their ratio were determined. In the second method, the ratio of Planktonic foraminifera to Epifaunal benthic foraminifera was determined via using Van der Zwaan equation, Depth= e (3.58718+(0.03534×%P), the obtained average depth was 130 meters for the most parts of the formation. In the third method, the morphotypes of planktonic foraminifera were used for determination of depth. Based on this method for the lower and middle parts, first and second morphotype groups (shallow areas indices) are abundant, showing a shallow sea. For the upper part the third morphotype groups (deeper areas indices) are abundant, indicating an open marine environment. The results showed that generally, the major parts of the Sarvak Formation has been deposited in a neritic environment and in the upper parts, depositional environment turned into a deeper one and reached the upper bathyal depths (340 m).
R Shabanian; N Ghanizadeh
Abstract
The Illanqareh Formation consists of sandstone, shale, dolomite, extrusive igneous rocks, and limestone. This Formation is about 400 m thick and crops out in the west of Illanlu village, south of the Aras dam, north of the West Azarbaijan province. The clastic deposits of the Illanqareh formation attributed ...
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The Illanqareh Formation consists of sandstone, shale, dolomite, extrusive igneous rocks, and limestone. This Formation is about 400 m thick and crops out in the west of Illanlu village, south of the Aras dam, north of the West Azarbaijan province. The clastic deposits of the Illanqareh formation attributed to the late Devonian and the upper carbonate division belongs to the early Carboniferous. The study of prepared thin sections resulted in recognizing 15 species related to 9 genera of 8 foraminifera families. The comparison of identified foraminifera' assemblage in the studied stratigraphical section with those from other Carboniferous formations of Iran and the world indicated a Tournasian- Visean age for the marine deposits of this formation. The Illanqarah formation in the Illanlu section overlies the early Devonian Muli formation and underlies the early Permian Doroud formation both disconformably.
M Sohrabi Mollayousefi; M Sahba
Abstract
The study area includes a part of the northern strip of Persian Gulf coast, a distance of approximately 650 kilometers. The Persian Gulf is a marginal, semi-closed, and shallow sea with salty and warm water. It has a circular flow in a clockwise direction along the coast of Iran, caused by the high range ...
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The study area includes a part of the northern strip of Persian Gulf coast, a distance of approximately 650 kilometers. The Persian Gulf is a marginal, semi-closed, and shallow sea with salty and warm water. It has a circular flow in a clockwise direction along the coast of Iran, caused by the high range of evaporation. The ecology characteristics of The Persian Gulf have created special microfauna among which the hyaline foraminifera were studied in this research. In addition to sampling of coastal sediments, physicochemical properties of water were measured. It was determined that the physicochemical factor affecting the development, abundance, and diversity of foraminifera is dissolved oxygen. In general, 29 genera and 35 species of foraminifera were identified among them the most common foraminifera contain calcareous hyaline shell. The ratio of biocenosis to taphocenosis has a direct relationship with the amount of environmental pollutants. However, as the pollution rate is increased, the quantity and diversity of biocenosis species is decreased and the taphocenosis is upgraded. Another important factor in the abundance of foraminifera is the bed sedimentological characteristics, as the frequency of biocenosis and taphocenosis is higher within the fine-grained beds, whereas, in the low or absence of pollution, the abundance of protoplasm-containing shells within the silty-muddy beds is much higher than the other areas.
M. Motamedalshariati; A. Sadeghi; H. Vaziri Moghadam; R. Moussavi Harami
Abstract
A stratigraphic section in west of Maraveh Tappeh town has been selected and measured in order to study the Aitamir Formation in north west of Kopeh Dagh. The Aitamir Formation with 1070 m thickness, consists of sandstone in the lower part and shale and marl in the upper part. The lower and upper boundaries ...
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A stratigraphic section in west of Maraveh Tappeh town has been selected and measured in order to study the Aitamir Formation in north west of Kopeh Dagh. The Aitamir Formation with 1070 m thickness, consists of sandstone in the lower part and shale and marl in the upper part. The lower and upper boundaries of the Aitamir Formation with Sanganeh and Abdraz Formations are conformable. The biostratigraphic studies led to identification of 34 genera and 58 species of planktonic and benthonic foraminifera. Based on foraminifera assemblage three biozones are suggested as follows: Rotalipora appenninica zone, Rotalipora brotzeni zone, Whiteinella aumalensis –Dicarinella canaliculata zone. These biozones coincidence with global biozones. Based on foraminiferal fauna, a Late Albian to Late Cenomanian age is suggested for the upper shale member of Aitamir Formation.
J. Daneshian; D, Baghbani; S.A. Aghanabati; N. Norouzi
Abstract
Oligocene-Lower Miocene sediments at Nareh section, situated in SW Jahrum consists of limestone, argillaceous limestone, marl and evaporatic sediments with a rich association of planktonic and benthonic foraminifera. In lower part of this succession, the Pabdeh sediments with a thickness of 115m is composed ...
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Oligocene-Lower Miocene sediments at Nareh section, situated in SW Jahrum consists of limestone, argillaceous limestone, marl and evaporatic sediments with a rich association of planktonic and benthonic foraminifera. In lower part of this succession, the Pabdeh sediments with a thickness of 115m is composed of shale, marl and intercalations of argillaceous limestone. The mentioned sediments continue through Late Eocene to Oligocene, which are overlain conformably by the Asmari Formation. The Asmari Formation consists of 250 m limestone and argillaceous limestone of which 210 m belongs to the lower Asmari and 40 m to middle Asmari. Argillaceous limestone and evaporatic-marly sediments of the Gachsaran Formation are overlain by the Asmari Formation. The Gachsaran Formation with a thickness of 510m is composed of three members of Chehel, Champeh and Moll. Pure and thick basal limestones of the Mishan Formation (Guri Member) with a thickness of 302 m, is situated above the Gachsaran Formation. Finally, Bakhtyari conglomerate lies uncomformably over the Mishan Formation. Variety of studied rock units in this section has caused different sedimentary environments, different facies and presence of abundant planktonic and benthonic foraminifera. By studying 203 samples including 193 hard and 10 washed samples, 34 genera and 47 species of benthonic foraminifera and 8 genera and 13 species of planktonic foraminifera, algae, briozoa and different macrofossils fragments were identified. Based on foraminiferal assemblages, the age of the lower part of the Pabdeh Formation is Late Eocene (Priabonian) and the upper part is Early Oligocene and the Asmari Formation is Oligocene (Late Rupelian-Chattian) to Early Miocene (Aquitanian). Also, the Gachsaran Formation belongs to Early Miocene (Aquitanian-Burdigalian) and the age of the Mishan Formation (Guri Member) is Late Miocene (Burdigalian) .On the basis of recognized foraminifera association, Nareh stratigraphical section can be correlated with first to fourth Biozones of biozonation of Adams and Bourgeois (1967) and 54,57,59,61,63 and 64 Biozones of Wynd (1965).
M. Asgharian Rostami; E. Ghasemi-Nejad; M. Shafiee Ardestani
Abstract
At this research are studied late cretaceous sediments at Ziarat-kola section, Central Alborz, in order to Palaeobathymetry and sea level change. These sediments are with about 200m thickness consist of monotonous Marl and limy marl. Based on Planktonic foraminifera gain Upper Maastrichtian stage (Abathomphalus ...
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At this research are studied late cretaceous sediments at Ziarat-kola section, Central Alborz, in order to Palaeobathymetry and sea level change. These sediments are with about 200m thickness consist of monotonous Marl and limy marl. Based on Planktonic foraminifera gain Upper Maastrichtian stage (Abathomphalus mayaroensis zone). In order toPalaeobathymetry and sea level change used to three methods common consisting of morphotype Planktonic foraminifera, ratio Planktonic foraminifera to benthic foraminifera and assigning genus and benthic foraminifera species. With morphotype analysis was indicated that third morphotype which are more deep index increase at the initial part and first morphotype that are shallow index increasing at middle section. In this manner, depth change was examinated to use two genus, Globotruncana (deep dweller) and Pseudoguembelina (Mixed layer dweller). In orther to assign paleodepth at this area used to Planktonic foraminifera to total foraminifera minus infaunal Benthic foraminifera and the regression equation [Depth = e (3. 58718 + (0. 03534 × %*p)].examination genus and Benthic foraminifera species depth index and such results gain at above method were indicating that this sediments in upper bathyal and middle bathyal. Thus, results indicate that beginning and end of are deeper from middle section.
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.
J. Daneshian; M. Shahrabi; M. Akhlaghi
Abstract
75 samples of the Qom Formation in Andabad, northeast Mahneshan, were investigated. The Qom Formation in the examined section with a thickness of 301m, mainly consists of limestone and marl, and disconformably overlies the Lower Red Formation and lies under the sediments of the Upper Red Formation. A ...
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75 samples of the Qom Formation in Andabad, northeast Mahneshan, were investigated. The Qom Formation in the examined section with a thickness of 301m, mainly consists of limestone and marl, and disconformably overlies the Lower Red Formation and lies under the sediments of the Upper Red Formation. A study of foraminifera was led to identifying 42 genera and 70 species of the benthonic and plankthonic foraminifera, which 37 genera and 57 species is reported from this area for the first time. Among them, benthonic foraminifera have more varieties and abundances, and used for biostratigraghy. Based on the identified foraminifera, the Andabad section is comparable to Assemblages Zone 1 and 2 introduced by Adams and Bourgeois. On the basis of occurrence of the index foraminiferal species and their stratigraphic distribution, the age of the Qom Formation in the studied section is Early Miocene (Late Aquitanian to Burdigalian).The assemblage, abundance, and species diversity of foraminifera in the examined samples shows noticeable changes in the paleoenvironmental conditions. The maximum diversity of foraminifera is sixteen species. Based on species diversity, the strata classified to nine assemblages A to I. The abundance of foraminifera in each assemblage indicates that the sediments of the Qom Formation belong to inner shelf environments.
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; 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.
