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.
Fatemeh Vaez-Javadi; Nasrollah Abbassi
Abstract
Jurassic deposits a section in south of Zanjan contain various taxa of macro and microfloras. Six plant macrofossil species belonging to five genera of various orders such as Equisetales, Cycadales, Bennettitales, and Pinales (Coniferales) are identified. This section contains seventeen species of palynomorphs ...
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Jurassic deposits a section in south of Zanjan contain various taxa of macro and microfloras. Six plant macrofossil species belonging to five genera of various orders such as Equisetales, Cycadales, Bennettitales, and Pinales (Coniferales) are identified. This section contains seventeen species of palynomorphs in which six spore species allocated to six genera, eight pollen species allocated to five genera, and three dinocyst species allocated to two genera are present. Based on the occurrence of Index fossils such as Ptilophyllum harrisianum, Nilssonia sp. cf. N. bozorga, and Equisetites sp. cf. E. beanii, an early Middle Jurassic (Aalenian-Bajocian) age suggested for these sediments. Therefore, these deposits considered to belong to the Dansirit Formation. Moreover, based on the stratigraphic distribution of index fossils of plant macrofossils, miospores, and dinocysts, three assemblage biozones recognized. These biozones are Nilssonia sp. cf. N. bozorga-Ptilophyllum harrisianum, Klukisporites variegatus-Cycadopites crassimarginis,and Pareodinia ceratophora-Nannoceratopsis triceras Assemblage Zone, respectively. All these biozones are comparable to the other Known Iranian biozones. Therefore, it is concluded that uniform environmental conditions are dominant through North, Central, and East Central of Iran during this interval. Furthermore, because of the occurrence of dinoflagellates, this area was located at the margin of Tethys Ocean.
T. Binazadeh; A. Binazadeh; T. Vafaei
Abstract
The Asmari Formation is a thick carbonate sequence in Zagros foreland basin (southwest of Iran). It was deposited during Oligocene – Early Miocene ages. The formation with a thickness of 233m cropped out in the Dashtroom section (15 km south of Yasuj). This formation was studied from microfacies, ...
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The Asmari Formation is a thick carbonate sequence in Zagros foreland basin (southwest of Iran). It was deposited during Oligocene – Early Miocene ages. The formation with a thickness of 233m cropped out in the Dashtroom section (15 km south of Yasuj). This formation was studied from microfacies, sedimentary environment and biostratigrarphy point of view. Study of benthic foraminifera led to recognition of 23 genera and 32 species. In general, three assemblage biozones were recognized in this formation, consisting of: 1. Lepidocyclina- Operculina- Ditrupa assemblage zone 2. Miogypsina– Elphidium sp., Peneroplis farsensis assemblage zone 3. Borelis melo curdica- Meandropsina iranica assemblage zone An age of Early Oligocene (Rupelian- Chattian)- Early Miocene (Burdigalian) is suggested for the formation at the study area. Based on laboratory studies, nine microfacies related to three subenvironments (lagoon, bar and open marine) were identified. This study revealed that, the Asmari Formation deposited on a homoclinal epicontinental carbonate ramp.
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.
A Gholami fard; A Kani; A Mahanipour
Abstract
This study investigates the Lower Cretaceous sedimentary succession comprising Sarcheshmeh Formation and Sanganeh Formation in the Ghaleh zoo Section from the standpoint of Calcareous Nannofossils. The results reveals presence of 60 species from 33 genera of 15 families. Based on the index nannofossil ...
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This study investigates the Lower Cretaceous sedimentary succession comprising Sarcheshmeh Formation and Sanganeh Formation in the Ghaleh zoo Section from the standpoint of Calcareous Nannofossils. The results reveals presence of 60 species from 33 genera of 15 families. Based on the index nannofossil taxa, the upper part of NC6, NC7A, NC7(B&C) and NC8(A&B) nannofossil zones (equivalent to the upper part of of CC7a, CC7b and CC8 zones), are present in this section. The calcareous nannofossils found in this section point to an Early Aptian to Late Aptian age of deposition for the rocks of Sarcheshmeh Formation and Late Aptian to Early Albian for the rocks of Sanganeh Formation.
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.
N Badri; A.L Kani
Abstract
The Gurpi Formation has a wide extent in the Zagros Sedimentary Basin.It has received considerable attention due to its unique stratigraphic position, chronostratigraphic importance, and floral and faunal diversity and abundance.In order to biostratigraphically classification and correlation of theGurpi ...
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The Gurpi Formation has a wide extent in the Zagros Sedimentary Basin.It has received considerable attention due to its unique stratigraphic position, chronostratigraphic importance, and floral and faunal diversity and abundance.In order to biostratigraphically classification and correlation of theGurpi Formation in Kuh-e-Gach andKuh-e Kurdeh sections (Lar region, Fars province), this study concentrated on the calcareous nannofloral content of sediments.From the prepared 300 microscopic slides, a total of 53 species from 30 genera belonging to 15 families were determined, described and photographed. The distribution of nannofloral assemblage of the Gurpi Formation in Kuh-e Kurdeh reveals presence of CC18 to CC24 zones indicating an Early Campanian to Early Maastrichtian age, while in Kuh-e Gach CC19 to CC24 zones with an age range of Early Campanian to Early Maastrichtian are present. Occurrence of various speciesof low latitude affinities points toward such positioning of depositional basin of the Gurpi Formation.
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.
Z Kiadaliri; M.R Majidifard
Abstract
The Lower- Middle Jurassic strata are well developed in northeast of Jajarm (E Alborz). At the study section, the Shemshak Group has a maximum thickness of 585 m, consisting of grey silty sandstones and light- green siltstones with brown sandstones, subdivided into 3 formations ofAlasht, Shirindasht ...
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The Lower- Middle Jurassic strata are well developed in northeast of Jajarm (E Alborz). At the study section, the Shemshak Group has a maximum thickness of 585 m, consisting of grey silty sandstones and light- green siltstones with brown sandstones, subdivided into 3 formations ofAlasht, Shirindasht and Fillzamin.The lower boundary of the Shemshak Group at Golbini sectionwith the red bauxite horizon of the underlying Elikah Formation is disconformity due to the EarlyCimmerian tectonic event.Its upper boundary with marly limestone and marl of the Dalichai Formation is disconformity, too. In the Shemshak Group at the study section, summing up 186 fossil specimens were collected, among which the ammonoids with 67 specimens clearly predominate and belonging to 6 biozones (ThouarsenseZone, Pseudoradiosa Zone,Aalensis zone, Opalinum Zone, Murchisonaezone, ConcavumZone) have been recognized. Based on the ammonite fauna, the age of the Shemshak Group in the investigated area ranges from the Upper Toarcian to Upper Aalenian. Paleobiogeographically, the fauna shows close relationship to Northwestern Europe and Sub-Mediterranean regions. This indicates a paleogeographical position of the area at the northern Tethys during the Lower-Middle Jurassic.
J Daneshian; K Younesi; A Azad; S.A Moallemi
Abstract
Two stratigraphic sections of Tang-e-Chenarbashi (712 meters) and Tang-e-Bavolak (870 meters) in the Kabir kuh anticline were selected for investigating planktonic foraminiferal biostratigraphy of the Sarvak Formation. These sections encompass of pelagic facies and containing rich microfauna of Middle ...
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Two stratigraphic sections of Tang-e-Chenarbashi (712 meters) and Tang-e-Bavolak (870 meters) in the Kabir kuh anticline were selected for investigating planktonic foraminiferal biostratigraphy of the Sarvak Formation. These sections encompass of pelagic facies and containing rich microfauna of Middle Albian to Cenomanian. The results of this study show the age of Middle Albian for lower strata of the Sarvak Formation. First appearance of Biticinella breggiensis correspond with the onset of Upper Albian strata, and is a cosmopolitan marker for Middle and Late Albian boundary. Also, based on investigated biozones including Ticinella roberti Zone, Ticinella primula Zone, Biticinella breggiensis Zone, Rotalipora ticinensis Zone, Paracostellagerina libyca zone, Microhedbergella rischi zone, Rotalipora cushmani Zone,Whiteinella archaeocretacea Zone, several paraconformities have been recognized in the examined sections.
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.
F. Dabbaghi Sadr; K. Seyed-Emami; M. Majidi Fard
Abstract
Upper Jurassic rocks are well developed at the western part of the Binalud Range (northeast Iran). These consist mainly of limestone, marlstone and marl with few intercalations of sandstone and conglomerate. The thickness of this succession in the study section (Bormahan, northwest of Neyshabour) ...
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Upper Jurassic rocks are well developed at the western part of the Binalud Range (northeast Iran). These consist mainly of limestone, marlstone and marl with few intercalations of sandstone and conglomerate. The thickness of this succession in the study section (Bormahan, northwest of Neyshabour) is 1084 meters and can be subdivided into 6 members. The lower boundary with the dark siliciclasts of ?Kashafrud Formation (Upper Bajocian / Lower4 Bathonian) is sharp. The upper boundary with buff and cliff-forming carbonates of the ?Mozduran Formation (Upper Jurassic) is transitional. Ammonites are the most important and abundant macrofossils.Totally more than 300 specimens have been collected, comprising 21 genera and 36 species.The relative abundances at the family level are: Phylloceratidae (48%), Perisphinctidae (42%), Oppeliidae (6%), Haploceratidae (2%), Aspidoceratidae (1%) Based on the ammonite fauna 15 biozones are recognized which can be fairly good compared with the ammonite biozonation of Sub-Mediterranean Province. According to the ammonite fauna an Early Bathonian to Kimmeridjian age is proposed.The ammonite fauna is closely related to those of the Sub-Mediterranean Province, indicading a permanent faunal exchange.
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.
H. Vaziri-Moghaddam; A. Safari; S. Shahriari; A. Khazaei; A. Taheri
Abstract
In order to study the biostratigraphy and palaeoecology of the Maestichtian deposits (Tarbur and Gurpi formations) in High Zagros, Gardbishe section in south of Borojen was selected. The Tarbur deposits in this region are mainly composed of carbonate and clastic a rock which has been overlaind by Gurpi ...
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In order to study the biostratigraphy and palaeoecology of the Maestichtian deposits (Tarbur and Gurpi formations) in High Zagros, Gardbishe section in south of Borojen was selected. The Tarbur deposits in this region are mainly composed of carbonate and clastic a rock which has been overlaind by Gurpi Formation. The lower contact of this formation is lower red unit as conformable contact. The Gurpi Formation is lithologically composed of marl which has been overlaind as a disconformable contact by Shahbazan dolomites. The biostratigrphic data based on benthic and planktonic foraminifera and rudists represents the late Maestrichtian age for the section. Two biozones were identified in Maestrichtian deposits including: Omphalocyclus-Loftusia assemblage zone, Contusatruncana contusa-Recemiguembelina fructicasa zone. In general, the suitable environmental conditions for diversity, frequency and increase in size of some fossils such as Loftusia and in the absence of some other fossils such as Orbitoides and Lepidorbitoides in this region can be related to augmentation of nutrients and entering the detrital and silica sediments due to river injection and runoff and consequently to the eutrophic conditions formed in the basin.
