Stratigraphy and Palaeontology
Peiman Rajabi
Abstract
The Asmari carbonate formation in Lorestan is seen in the form of a medium to the thick limestone-rich layer of benthic foraminifera and often as a rock formation. In this study, the stratigraphic sequence of Asmari carbonate formation in the Chenareh Anticline section located in the south of Lorestan ...
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The Asmari carbonate formation in Lorestan is seen in the form of a medium to the thick limestone-rich layer of benthic foraminifera and often as a rock formation. In this study, the stratigraphic sequence of Asmari carbonate formation in the Chenareh Anticline section located in the south of Lorestan basin and Amiran Anticline section located in the middle part of Lorestan basin were studied in terms of lithology and micro biostratigraphy. The thickness of the Chenareh Section was 180 meters and the Section of Amiran Anticline was 158 meters. In total, more than 290 thin sections of both were prepared and examined in the laboratory. The results of fossil studies based on the expansion of foraminifera finally lead to the introduction and presentation of 1 Assemblage biozone in the Amiran anticline section and 3 Assemblage biozones related to the Chenareh anticline stratigraphic section. Accordingly, the age of the Asmari Formation is in the Chenareh section is Oligo-Miocene (Chattian-Bordigalian) and in the Amiran section is Miocene (Bordigalin). According to the lithostratigraphic studies, the border of the Asmari Formation in both sections of Chenareh and Amiran with Shabazan Formation is progressive-continuous and discontinuous, and in both sections of the upper boundary with Gachsaran Formation can be seen in the same way as evaporative sediments.
Stratigraphy and Palaeontology
Fatemeh Vaez-Javadi; Mahdi Abbaszadeh
Abstract
Middle Jurassic sediments of the Hojedk Formation have been well-exposed in the Central East of Iran. In this study, plant macrofossils, which are collected from a coal exploratory well in the Mazino area, southwest of the Tabas were studied, so that 29 species of well-preserved plant macrofossils belonging ...
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Middle Jurassic sediments of the Hojedk Formation have been well-exposed in the Central East of Iran. In this study, plant macrofossils, which are collected from a coal exploratory well in the Mazino area, southwest of the Tabas were studied, so that 29 species of well-preserved plant macrofossils belonging to 15 genera of various orders such as Equisetales, Filicales, Caytoniales, Bennettitales, Cycadales, and Pinales were identified. One local biozone- Ptilophyllum harrisianum-Klukia exilis interval zone was recognized. The lower and the upper boundaries of this biozone were identified by the first and the last occurrences of index species. Based on the occurrences of the Equisetites sp. cf. E. beanii, Klukia exilis, Ptilophyllum harrisianum, Nilssonia macrophylla, and Elatides thomasii, an early Middle Jurassic age (Aalenian-Bajocian) was suggested for this plant assemblage. The relative abundance of Filicales (ferns), Cycadales, Pinales, and Equisetales are 43.18, 31.82, 13.63, and 4.64 percent, respectively. Moreover, the results of similarity indices of plant macrofossils indicate relatively strong value of similarity between the plant macrofossil assemblage of the Mazino area and elsewhere in the Tabas Block. Besides, the floral gradient score of this assemblage is 54.89. Based on the paleontological and lithological evidence, a humid ‘warm temperate biome’ is considered for this locality. Moreover, it is confirmed that a uniform vegetation and palaeoclimate occurred in Tabas Block during the Middle Jurassic and that Iran was located within Vakhrameev’s Euro-Sinian region, as Transcaspian subprovince.
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
Narges Ghader; Ali Asghar Ciabeghodsi; Mir Amir Salahi; Mohammad sadegh Zangeneh
Abstract
In the present study, In order to study of the planktonic foraminiferal biostratigraphy of Qom Formation in north of Khoy city, West Azarbayjan province (Sanandaj-Sirjan fore-arc basin), stratigraphic section of Sagatlu was selected and sampled. Thickness of Sagatlu section 216 meters was measured. Lithology ...
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In the present study, In order to study of the planktonic foraminiferal biostratigraphy of Qom Formation in north of Khoy city, West Azarbayjan province (Sanandaj-Sirjan fore-arc basin), stratigraphic section of Sagatlu was selected and sampled. Thickness of Sagatlu section 216 meters was measured. Lithology of this section contain shale, siltstone, conglomerate and sandstone. The lower boundary of these deposits is alluvium, and its upper boundary is hard limestone deposits of Qom Formation. Study of the planktonic foraminifera communities found in the mentioned section to identify 16 genera and 37 species of planktonic foraminifers. In this research, 4 biozone are included, Subbotina linaperta assemblage Zone, Paragloborotalia opima Highest-occurrence Zone, Ciperoella ciperoensis Partial-Range Zone, Globigerinoides italicus assemblage Zone were identified as being age equivalent to Priabonian-Burdigalian and comparable to world standard biozones..
Stratigraphy and Palaeontology
shahram navavajary; Iraj Maghfouri Moghaddam; Ali Reza Shahidi; Hamid Nazari
Abstract
Oligo-Miocene rocks are deposited between Pyrenean and Pasadenian orogenic phases. This rocks in central Iran back arc deposits are named Qom formation. There are well developed outcrops of Qom formation at the North of Central Iran zone. In order to study microbiostratigraphy of the formation, Three ...
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Oligo-Miocene rocks are deposited between Pyrenean and Pasadenian orogenic phases. This rocks in central Iran back arc deposits are named Qom formation. There are well developed outcrops of Qom formation at the North of Central Iran zone. In order to study microbiostratigraphy of the formation, Three sections, north west of Darjazin town , Bonak mount and Arvaneh were selected. In these sections Qom formation with discontinuity overlays the Lower Red formation and with the same quality under the Late Miocene Conglomerate with intercalations of Sandstone, which is equivalent to the Upper Red Formation is placed. The main lithological composition of the Qom Formation in the study area alternates between layers of limestone and Marl with intercalations of siliciclastic rocks. Members and submembers of the Qom formation type area are not visible in this area and can only based on the lithological characteristics divide to local units. Based on bentic foraminifera and other microbiostratigraphical data, Qom Formation age in north west-west of Semnan (Darjazin-After zone), which is located in the Central Alborz structural- sedimentary zone, is early Miocene epoch and Burdigalian stage, which is the equivalent of Borelis melo curdica-Borelis melo biozone.
Stratigraphy and Palaeontology
kiana kiarostami; Darioush Baghbani; Seyed Mohsen Aleali; Seyed Ali Aghanabati; Mohammad Parandavar
Abstract
Lithostratigraphy and biostratigraphy studies on the Sarvak Formation in type section (Tang- e Sarvak, Northwest of Behbahan) show that this Formation has 710 meter thicknesses that divided in to four lithostratigraphic units. The Sarvak Formation in type section rests on the Kazhdumi Formation conformably ...
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Lithostratigraphy and biostratigraphy studies on the Sarvak Formation in type section (Tang- e Sarvak, Northwest of Behbahan) show that this Formation has 710 meter thicknesses that divided in to four lithostratigraphic units. The Sarvak Formation in type section rests on the Kazhdumi Formation conformably with gradational contact (black shales and black argillaceous limestone) and under the Gurpi Formation with disconformity boundary. In this study 8 genus and 9 species of planktonic foraminifera and 34 genera and 33 species of benthic foraminifera have been reported. Four biozones based on (wynd, 1965) and two biozone based on) Premoli Silva and Verga 2004) have been reported as follow; Four biozones based on Wynd 1965: 1- Favusella washitensis range Zone # 23,2- '' Oligostegina'' facies # 26,3- Rudist debris # 24, 4- Nezzazata– Alveolinids Assemblage Zone # 25, Tow biozones based on Premoli Silva and Verga 2004: 1-Muricohedbergella planispira Zone, 2-Ticinella primula Zone. It can propose an Albian- Cenomanian age for Sarvak Formation based on these biozones and also it can recognize Albian-Cenomanian boundary on occurrence of Muricohedbergella planispira and Whiteinella sp. in lower part of this Formation.
Stratigraphy and Palaeontology
Katayoon Barmakizadeh; A. Mahanipour
Abstract
Abstract The lower part of the Garau Formation with a thickness of 212 m at the southwest of the Kabirkuh anticline is investigated with regard to the calcareous nannofossils. Lithology of the studied interval is mainly consists of marl, marly limestone, black shale and limestone. 67 species from 33 ...
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Abstract The lower part of the Garau Formation with a thickness of 212 m at the southwest of the Kabirkuh anticline is investigated with regard to the calcareous nannofossils. Lithology of the studied interval is mainly consists of marl, marly limestone, black shale and limestone. 67 species from 33 genus and 13 families are recognized. Nannofossil events that are recorded from base to top of the section are as follow: the first occurrence (FO) of Calcicalathina oblongata, the last occurrence (LO) of Rucinolithus wisei, the FO of Lithraphidites bollii, the LO of Cruciellipsis cuvillieri, the first occurrence of Assipetra terebrodentarius and the last occurrence of Lithraphidites bollii. According to these index calcareous nannofossils, the studied interval is ranging from the uppermost part of CC2/NK2 biozone to the middle part of CC5b/NC5C subzone Considering these zonations, the age of the studied interval is Valanginian ‒ Hauterivian. According to the calcareous nannofossil data, the Valanginian ‒ Hauterivian boundary can’t be determined. This boundary is located at the base of the Tethyan ammonite Acanthodiscus radiatus at the leading GSSP candidate in the La Charce section of southeastern France.
S. Sanjary; F. Hadavi; M. Notghi Moghaddam; M. Allameh
Abstract
In the present study the Abderaz Formation ostracods were investigated. The thickness of the formation in this section is 385m, and consists of shale and marl together with three horizons of chalky limestone. Paleontological studies led to identification of 16 genera and 51 species of ostracods ...
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In the present study the Abderaz Formation ostracods were investigated. The thickness of the formation in this section is 385m, and consists of shale and marl together with three horizons of chalky limestone. Paleontological studies led to identification of 16 genera and 51 species of ostracods and differentiation of four biozones in this section. According to the ostracods and correlation with calcareous nannofossils in this section, an age of late Santonian to early late Campanian is quoted to the formation at this section. Presence of warm water index species and absence of cool water forms suggest warm surface waters. Also changes in depth and oxygen were concluded during depositional course of the formation.
A. Yavari; M. Ghavidel syooki; M. R. Majidifard; S. H. Vaziri
Abstract
The Kazhdumi Formation is well exposed and accessible in Tang-e Maghar, northwest of Behbahan city, Zagros basin. In this area, this formation has a thicknees of 344 m and it mainly consists of alternation of black - gray shale with medium – thin-bedded cream – gray argillaceous limestone. ...
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The Kazhdumi Formation is well exposed and accessible in Tang-e Maghar, northwest of Behbahan city, Zagros basin. In this area, this formation has a thicknees of 344 m and it mainly consists of alternation of black - gray shale with medium – thin-bedded cream – gray argillaceous limestone. The lower contact of the Kazhdumi Formation is disconformable with Daryan Formation and conformable with the Sarvack Formation at the top. A total of 220 ammonite bearing surface samples were collected including the uppermost part of the Daryan Formation (5m) and the whole thickness of the Kazhdumi Formation (344m). This investigation resulted in 21 species (15 genera) which belong to six families. The encountered ammonite species of the upper part of the Daryan Formation and the whole Kazhdumi Formation consist of Douvilleiceras sp., Douvilleiceras cf. mammillatum, Epicheloniceras subnodosocostum– buxtorfi, Hypacanithoplites cf. elegnas, Acanthohoplites cf. aschiltaensis, Nolaniceras nolani, Parahoplites cf. melchioris, Venezoliceras sp., Venezoliceras cf. venezolanum, Mirapelia cf. buarquianum, Mirapelia sp., Oxytropidoceras carbonarium, Oxytropidoceras cf. roissyanum, Hysteroceras cf. orbignyi, Hysteroceras sp., Tonohamites cf. aequicingulatus, Mortoniceras sp., Mortoniceras aff. inflatum, Dufrenoyia sp., Hemiptychoceras cf. gaultinum and Scaphites sp.Amongst these ammonite species, Scaphites sp. and Hemiptychoceras gaultinum are recorded for the first time and the remainder has previously been recorded from this rock unit in the Zagros basin. Likewise, based on stratigraphic potential of the encountered ammonite species the lower Aptian is suggested for the upper part of the Daryan Formation and upper Aptian –upper Albian for the Kazhdumi Formation.Therefore, a hiatus is present between the Daryan and Kazhdumi formations, encompassing the middle Aptian.
F. Vaez-Javadi
Abstract
Hojedk Formation spreads well through the Tabas Block. Diverse and moderately preserved palynofloras occur in the Middle Jurassic sediments of the formation in south Kouchekali, southwest of Tabas, central-east Iran. The present investigation of the Hojedk Formation has revealed a diverse assemblage ...
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Hojedk Formation spreads well through the Tabas Block. Diverse and moderately preserved palynofloras occur in the Middle Jurassic sediments of the formation in south Kouchekali, southwest of Tabas, central-east Iran. The present investigation of the Hojedk Formation has revealed a diverse assemblage of dinoflagellate cysts in which 12 species allocated to 5 genera. Two acritachs were also recognized, permitting establishment of Nannoceratopsis triceras-Pareodinia ceratophora Assemblage zone, and Nannoceratopsis gracilis Total Rane Subzone in the upper part, lower and upper boundaries have been identified by the first and last observed occurrence (LOO) of these index species. These biozones are comparable to the other palynozones in Iran and elsewhere especially in the northern hemisphere (Greenland, Norway, Scotland, England, and Poland). Occurrence of various species of Nannoceratopsis is concluded that this locality was located at the south palaeocoastal line of the Tabas Block during the Aalenian-Bajocian.
Stratigraphy and Palaeontology
S. Senemari
Abstract
Calcareous Nannofossils of the Gurpi Formation have been investigated at Kalchenar section (Northwest of Izeh). In this section, the Gurpi Formation is mainly consists of marls, shaly marls and marly limestones. For introducing index species, calcareous nannofossil assemblages and biozones, 150 slides ...
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Calcareous Nannofossils of the Gurpi Formation have been investigated at Kalchenar section (Northwest of Izeh). In this section, the Gurpi Formation is mainly consists of marls, shaly marls and marly limestones. For introducing index species, calcareous nannofossil assemblages and biozones, 150 slides have been studied which led to the recognition of twelve biozones. As a result, 61 species, 35 genera of calcareous nannofossils were detected. According to the identified biozones, the age of the Gurpi Formation is Late Campanian to Late Paleocene (Late Selandian) and K/Pg boundary is continuous at the studied interval, that is corresponding to CC21- CC26of zonation scheme of Sissingh (1977) and NP1- NP6 of zonation of Martini (1971).
A Mahanipour; A Najafpour; M Dastanpour
Abstract
Calcareous nannofossils have been investigated at the lower part of the Gurpi Formation at the southwest of Gurpi anticline. According to the index calcareous nannofossils CC22/UC15eTP to CC24/UC18 bio-zones have been identified and the age of Late Campanian ‒ Early Maastrichtian is considered for ...
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Calcareous nannofossils have been investigated at the lower part of the Gurpi Formation at the southwest of Gurpi anticline. According to the index calcareous nannofossils CC22/UC15eTP to CC24/UC18 bio-zones have been identified and the age of Late Campanian ‒ Early Maastrichtian is considered for the studied interval. Statistical analysis of the assemblages indicate the presence of high and low nutrient taxa. The relative abundance of oligotrophic taxa (Watznaueria barnesae, Watznaueria fossacincta, Prediscosphaera spp., Eiffellithus spp., Lithraphidites carniolensis, Staurolithites spp., Micula staurophora, Cribrosphaerella ehrenbergii) is higher than eutrophic forms (Biscutum constans, Discorhabdus ignotus, Placozygus spiralis, Reinhardtites spp., Zeugrhabdotus spp., Tranolithus orionatus), and an increasing trend in the relative abundance of oligotrophic taxa along with a decreasing trend in the relative abundance of eutrophic forms can be observed towards the upper parts of the section (Campanian-Maastrichtian boundary and Early Maastrichtian).
L Fazli
Abstract
For biostratigraphy of the Gurpi Formation, three sections of Halegan well, Kuh-e-Harm and Kuh-e- Nareh were selected and sampled in south Qir, Fars province. The formation is 152m thick in Kuh-e- Harm section, 124m in Kuh-e Nareh section and 128 m in well Halegan and is mainly containing argillaceous ...
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For biostratigraphy of the Gurpi Formation, three sections of Halegan well, Kuh-e-Harm and Kuh-e- Nareh were selected and sampled in south Qir, Fars province. The formation is 152m thick in Kuh-e- Harm section, 124m in Kuh-e Nareh section and 128 m in well Halegan and is mainly containing argillaceous limestone with interbeds of limestone. In Kuh-e-Harm section and Halegan well the Gurpi Formation unconformably overlies the Ilam formation and underlies the Pabdeh Formation. In Kuh-e- Nareh, the Gurpi Formation conformably overlies Ilam Formation and unconformably underlies the Pabdeh Formation. A total of 108 samples were collected and studied from the three sections mentioned and 25 Species of planktonic foraminifera belonging to 10 genera and 3 species of benthic foraminifera were identified.
On the basis of the planktonic foraminifera the age of the Gurpi Formation was determined as Campanian to Maastrichtian in Kuh-e- Harm and Halegan well and Santonian to Maastrichtian in Kuh-e-Nareh. A few biozones differentiated here are comparable with global biozones of Caron 1985 and Wynd 1963. Based on the distribution of planktonic foraminifera 6 biozones are identified as follow:
Globotruncanita elevate Partial Range Zone .
Globotruncana ventricosa Interval Range Zone .
Radotruncana calcarata Total Range Zone .
Globotruncanella havanensis Partial Range Zone .
Globotruncana aegyptica Interval Range Zone .
Gansserina gansseri Interval Range Zone .
In Halegan well Globotruncana falsostuarti zone instead of Globotruncanella havanensis Zone and Globotruncana aegyptiaca biozone was erected by the author. This zonation can be correlated with Globotruncanita elevate Total Range Zone and Globotruncanita stuarti- pseudotextullaria varians Assemblage Zone of Wynd, 1963.
B Asadi; A Sadeghi
Abstract
For biostratigraphy of the Ilam Formation, in Surgah and Kabirkuh anticlines, 2 sections of Mehdiabad and Holostem - Poshte were selected and sampled. The thickness of the Ilam Formation in Mehdiabad and Holostem - Poshte sections are 183 and 66 meters respectively and main lithology includes limestone, ...
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For biostratigraphy of the Ilam Formation, in Surgah and Kabirkuh anticlines, 2 sections of Mehdiabad and Holostem - Poshte were selected and sampled. The thickness of the Ilam Formation in Mehdiabad and Holostem - Poshte sections are 183 and 66 meters respectively and main lithology includes limestone, shale and argillaceous limestones with intercalation of shale. The lower and upper boundaries of the Ilam Formation with Surgah and Gurpi formations are conformable with sharp lithology changes. For biostratigraphic studies 36, species belong to 15 genus of formaminifera were recognized and 4 biozones based on Premoli Silva &Verga (2004) biozonation were identified. These include:
1. Dicarinellaconcavata zone
2. Dicarinellaasymetrica zone
3. Globotruncanitaelevata zone
4. Globotruncanaventricosa zone
Based on these biozons, the age of the Ilam Formation in both sections is Santonian – early Middle Campanian. In this study, the Ilam Formation in Mehdiabad and Holostem – Poshteh sections were compared with type section.
F Chegeni; D Baghebani; S.H Vaziri; T Mohtat; N Kohansal Ghadimvand
Abstract
For the purpose of biozonation of the Pabdeh Formation (Middle-Upper Eocene) based on planktonic foraminifera, a stratigraphic section in the southern slope of the Mishan Mountain and another in the Eshgar Mountain were studied. The thickness of these sections is 162.5 and 150 meters, respectively. The ...
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For the purpose of biozonation of the Pabdeh Formation (Middle-Upper Eocene) based on planktonic foraminifera, a stratigraphic section in the southern slope of the Mishan Mountain and another in the Eshgar Mountain were studied. The thickness of these sections is 162.5 and 150 meters, respectively. The Pabdeh Formation in the southern slope of the Mishan Mountain consists of marl, marly limestone, shale and limestone, and in the Eshgar Mountain includes alternating cream limestone and thin-bedded marl. In this study, most of the identified microfauna are Planktonic foraminifera. Identified Planktonic and benthic foraminifers in the southern slope of the Mishan Mountain include 18 genera and 8 species, and in the Eshgar Mountain include 21 genera and 10 species. Also four biozones are introduced of which one belongs to the Mishan Mountain and three belong to the Eshgar Mountain as follow: Hantkenina nuttalli Range Zone; Hantkenina nuttalli Turborotalia cerro-azulensis Interval Zone; Turborotalia cerro-azulensis Range Zone; Turborotalia cerro-azulensis/ Hantkenina sp. Assemblage Zone.
S Abbasi; B Hamdi; M.R Majidifard
Abstract
Study of conodont fauna from the Illanghareh Formation in Illanghareh, Illanlu and Pir-Eshag sections provide new data on the stratigraphy of this formation in the North West Iran. Illanghareh section is a terrigenous-carbonate rock sequence, consists mainly of quartzarenite sandstone, shale, and carbonate ...
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Study of conodont fauna from the Illanghareh Formation in Illanghareh, Illanlu and Pir-Eshag sections provide new data on the stratigraphy of this formation in the North West Iran. Illanghareh section is a terrigenous-carbonate rock sequence, consists mainly of quartzarenite sandstone, shale, and carbonate rocks. This sequence generally represents shallow-water Polygnathid-Icriodid biofacies and yielded five biozones: varcus, Older than rhenana, rhenana – linguiformis, Middle triangularis – Late trachytera, postera – expansa. Tectonic activities and erosion caused the Middle Devonian strata in the base of Illanghareh section to be omitted and the varcus Biozone is not recorded. Upper Devonian (Upper Famennian) rock units change into Carboniferous strata with a sedimentary gap though it is not recognizable in the field and no evidence of erosional surface is recognized. It is however, shown between Late Famennian and Late Turnaisian via conodonts recorded. The biozone bilineatus- bolandensis was also recorded in lower part of Carboniferous strata studied here.
B Mostafavi; F Hadavi; M Allameh; M Notghi Moghaddam
Abstract
The Abtalkh Formation is one of the Cretaceous sedimentary units of Kopeh-Dagh sedimentary basin that consist shale and marl. This formation is rich in ostracods. This study lead to recognition of 18 genera and 48 species. The recognized assemblages of ostracods is compared with those reported from Iran ...
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The Abtalkh Formation is one of the Cretaceous sedimentary units of Kopeh-Dagh sedimentary basin that consist shale and marl. This formation is rich in ostracods. This study lead to recognition of 18 genera and 48 species. The recognized assemblages of ostracods is compared with those reported from Iran and other adjacent regions. Based on the identified species three biozones (Cytherelloidea sp1, Veenia sp2, Limburgina sp.) have been determined in this section. According to the established ostracod biozones and correlation with biozones provided based on nannofossil, the age of the Abtalkh Formation in the studied section is Late Campanian- Early Maastrichtian- Late Maastrichtian.
M Hadi; H Mosaddegh; N Abbassi
Abstract
Carbonate successionsof the Ziarat Formation with introduce the Baghdareh and Gheynarjehsections in the Soltanieh Mountains(southern Zanjan) are rare locality in the western Alborzzone,which are contains of great abundance oflarge benthic foraminifera (LBF), particularly species of Alveolina. In fact, ...
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Carbonate successionsof the Ziarat Formation with introduce the Baghdareh and Gheynarjehsections in the Soltanieh Mountains(southern Zanjan) are rare locality in the western Alborzzone,which are contains of great abundance oflarge benthic foraminifera (LBF), particularly species of Alveolina. In fact, from this succession described some of Alveolinaspecies and their comparative stratigraphic distribution with the Alveolina species in the Tethyanbasinwhich is represent close affinitieswith coeval Alveolinaassemblages described in diVerent studies from this province. Also, this correlation shows Ilerdian-Cusianstages of study area that characterized by A. ellipsoidalis, A. laxa, A. tumida, A.cemali, A.aragonensis, A. pisiformis,A.rotundata, A.subpyrenaica, A. cf. canavari, A. canavari, A.ex gr. cremae species.
S Rahimi; A Sadeghi; M.R Partoazar
Abstract
In this research, the biostratigraphy of the Gurpi Formation in Kuh-e-Sefid section in east of Ramhormoz is studied. The thickness of the Gurpi Formation is 190.5m and consists mainly of shale, argillaceous limestone and marl. The lower boundary with the Ilam Formation is comformable with sharp lithology ...
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In this research, the biostratigraphy of the Gurpi Formation in Kuh-e-Sefid section in east of Ramhormoz is studied. The thickness of the Gurpi Formation is 190.5m and consists mainly of shale, argillaceous limestone and marl. The lower boundary with the Ilam Formation is comformable with sharp lithology and upper boundary with the Pabdeh Formation is unconformable with a gap between Late Maastrichtian and Late Paleocene. In this study, 47 species belonging to 17 genera and 8 biozones of planktonic foraminifera were recognized. The biozones consist of Dicarinella asymetrica zone, Globotruncanita elevate zone, Globotruncana ventricosa zone, Radotruncana calcarata zone, Globotruncanella havanensis zone, Globotruncana aegyptiaca zone, Gansserina gansseri zone, and Racemiguembelina fructicosa zone. The age of the Gurpi Formation based on these biozones is Late Santonian to Late Maastrichtian in this section.
T Sarbandi Farahani; M.R Majidifard; M.R Kebriaee- Zadeh; M Mohammadi
Abstract
The Middle Jurassic rocks are widely distributed and superbly exposed in the AlborzMountains (Northern Iran). In the central part of the mountain range, near Mahdishahr (Northern Semnan), the Dalichai Formation, from the underlying conglomerate and sandstones of Shemshak Formation to the limestones of ...
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The Middle Jurassic rocks are widely distributed and superbly exposed in the AlborzMountains (Northern Iran). In the central part of the mountain range, near Mahdishahr (Northern Semnan), the Dalichai Formation, from the underlying conglomerate and sandstones of Shemshak Formation to the limestones of the overlying Lar Formation, is completely exposed on the southern slopes of the kuh-e-Rahband. At this area, the sedimentary succession with nearly 122 m thickness subdivided into four members starting with marl and medium to thick-bedded grey limestones to marly limestones. The lower boundary with the siliciclastics of the underlying Shemshak Formation is disconformity, whereas the upper boundary with the light and cliff-forming carbonates of the Lar Formation is rather inconspicuous and transitional. The Dalichai Formation in the east of Mahdishar section is fossiliferous. The ammonite fauna consist of 5 families, 22 genera and subgenera and 40 species, among them 8 species are recorded for the first time from Iran. Based on the ammonite fauna, 9 biozones were recognized that indicated the age of the Dalichai Formation in the investigated area ranges from the Upper Bajocian? to Upper Oxfordian. Pleobigeographically, the fauna shows close relationship to west Europe and sub-mediterranean regions. This indicates a paleogeographic position of the area at the northern Tethys during the Middle Jurassic.
A Sadeghi; M Raziani
Abstract
In order to study of the Surgah Formation in Southwest of Ilam City, one section in the Shah Nakhjir anticline was selected. The thickness of the Surgah Formation is about 161 meters and consists mainly of green shales and olive green marly shales with intercalation of gray shaly limestones. The lower ...
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In order to study of the Surgah Formation in Southwest of Ilam City, one section in the Shah Nakhjir anticline was selected. The thickness of the Surgah Formation is about 161 meters and consists mainly of green shales and olive green marly shales with intercalation of gray shaly limestones. The lower and upper boundaries of the Surgah Formation are the Sarvak and Ilam Formation, respectively and are conformable with sharp lithology and abundant iron nodules. In this study, 52 species belonging to 28 genuses of foraminifera and 3 biozones were identified. Based on the planktonic foraminifera and identified biozones, the Surgah Formation has an age of Late Turonian to early Late Santonian. Comparison of biozones identified in this section with those of the type section in Tang-e- Garab shows that these two sections are similar in biozones and age, and the only difference is in thickness of biozones.
H Gholamalian; S Ghoreishi Maremy; M Parvaneh Nezhad Shirazi
Abstract
The Bahram Formation equivalent sequence in the Gerik section (eastern Zarand) displays middle Frasnian to early Famennian age on the basis of conodont investigation. Twenty-eight species and subspecies were identified. Seven biozones were recognized on the basis of vertical distribution of these taxa ...
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The Bahram Formation equivalent sequence in the Gerik section (eastern Zarand) displays middle Frasnian to early Famennian age on the basis of conodont investigation. Twenty-eight species and subspecies were identified. Seven biozones were recognized on the basis of vertical distribution of these taxa along the stratigraphic column; older than Upper hassi Zone, Upper hassi – jamieae zones, ?Lower rhenana Zone, Upper rhenana – linguiformis zones, Lower triangularis, Middle triangularis - Lower crepida zones, Middle – Upper crepida zones. Index conodont species those are recovered from the biostrome horizon in the lower part of section proved the middle Frasnian age (Upper hassi – jamieae zones). From view of conodont fauna, lithostatigraphy and age; the Gerik section is comparable with other successions of the Bahram Formation in Kerman, Tabas and Esfahan areas and shows a shallow sedimentary environment.
S Azadbakht; M.R Majidifard; S.A Babazadeh
Abstract
In this study, the Surgah formation is identified and introduced for the first time in the east of Khoram-Abad. This formation in the east of Khoram-Abad consists of up to 260 meters light grey, thin to thick –bedded limestone with intercalation of shaly-limestone and a Turonian to Santonian age. ...
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In this study, the Surgah formation is identified and introduced for the first time in the east of Khoram-Abad. This formation in the east of Khoram-Abad consists of up to 260 meters light grey, thin to thick –bedded limestone with intercalation of shaly-limestone and a Turonian to Santonian age. In this section, the Surgah formation has continuous and conformable contacts with the lower Sarvak formation and the upper Ilam formation. In this study, 13 genera, 33 species and 3 biozones of the planktonic foraminifera have been recognized: Biozon I, Helvetoglobotruncanahelvetica-Clavihedbergella –Hedbergella Assemblage Zone indicating Turonian age, Biozon II, Marginotruncana sigali- Marginotruncana schneegansi Assemblage Zone indicating Coniacian age, and Biozone III, Globotruncana ventircosa -Dicarinella concavata Assemblage Zone showing Santonian age.
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.
M. Asgharian Rostami
Abstract
In order to study the Gurpi formation for biostratigraphical purposes the 310 meters thick section was sampled at Mish-khas Sectiona, Ilam province. The sequence is mainly made up of monotonous marl, limy marl and Limestone and contains two formal members of Lopha (with brachiopod, Echinoid and Bivalve) ...
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In order to study the Gurpi formation for biostratigraphical purposes the 310 meters thick section was sampled at Mish-khas Sectiona, Ilam province. The sequence is mainly made up of monotonous marl, limy marl and Limestone and contains two formal members of Lopha (with brachiopod, Echinoid and Bivalve) and Emam-Hasan. Lower boundary Gurpi formation is contineous with Ilam Formation.At boundary both formation, Gray marl Gurpi formation located on limestone and limy marl at Ilam formation and upper boundary is continus with Pabdeh Formation. Sixty seven species belonging to 26 genera were identified and fourteen biozones were differentiated. These are: 1.Globotruncanita elevata partial range zone, 2. Globotruncana ventricosa interval zone, 3.Radotruncana calcarata total range zone, 4. Globigerinelloides subcarinatus partial range zone, 5.Globotruncana aegyptiaca partial range zone, 6. Gansserina gansseri partial range zone, 7.Contusotruncana contusa partial range zone, 8. Pseudotextularia intermedia partial range zone, 9. Racemiguembelina fructicosa partial range zone, 10.Pseudoguembelina hariaensis partial range zone, 11. Pseudoguembelina palpebra partial range zone, 12. Praemurica uncinata interval zone, 13. Morozovella angulata- Globanomalina pseudomeandri interval zone, 14. Globanomalina pseudomenardi total range zone. According to the planktonic foraminifera the formation encompases Lower Campanian to late Paleocene (Thanetian). lack of Marginotruncanid and Dicarinella asymetrica showing lower campanian for bas of section.There is distinct hiatus in Cretaceous-Paleogene boundary based on paleontology and sedimentology evidence. Analysis of Planktonic and Benthic foraminifers' assemblage at this section with Cretaceous biostratigraphical provinces is indicating a close similarity with those of Tethyan provinces.
