Geological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220سخن سردبیرسخن سردبیر2242502FAJournal Article20170130سخن سردبیرسخن سردبیرhttp://www.gsjournal.ir/article_42502_31054b58bdd14c2a9f815fa1d2586989.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220داورانداوران3342503FAJournal Article20170130داورانداورانhttp://www.gsjournal.ir/article_42503_6d33c1d9a56bae0e7cd748c3b4577edd.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Biostratigraphy of the Gurpi Formation in Kuh-e-Sefid Section, East of RamhormozBiostratigraphy of the Gurpi Formation in Kuh-e-Sefid Section, East of Ramhormoz3104255510.22071/gsj.2015.42555FAS RahimiM.Sc., Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, IranA SadeghiAssistant Professor, Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, IranM.R PartoazarPh.D. Student, Department of Geology, Islamic Azad University, Science and Research Branch, Tehran, IranJournal Article20110918In 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 <em>Dicarinella asymetrica</em> zone<em>, Globotruncanita elevate</em> zone<em>, Globotruncana ventricosa</em> zone<em>, Radotruncana calcarata</em> zone<em>, Globotruncanella havanensis</em> zone<em>, Globotruncana aegyptiaca</em> zone<em>, Gansserina gansseri</em> zone, and<em> Racemiguembelina fructicosa</em> zone. The age of the Gurpi Formation based on these biozones is Late Santonian to Late Maastrichtian in this section.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 <em>Dicarinella asymetrica</em> zone<em>, Globotruncanita elevate</em> zone<em>, Globotruncana ventricosa</em> zone<em>, Radotruncana calcarata</em> zone<em>, Globotruncanella havanensis</em> zone<em>, Globotruncana aegyptiaca</em> zone<em>, Gansserina gansseri</em> zone, and<em> Racemiguembelina fructicosa</em> zone. The age of the Gurpi Formation based on these biozones is Late Santonian to Late Maastrichtian in this section.http://www.gsjournal.ir/article_42555_c3ff6320a170ac53c848aff7fc642ad9.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Early Carboniferous Brachiopod Assemblages from the Mobarak Formation in Labrud Section, Northern DamghanEarly Carboniferous Brachiopod Assemblages from the Mobarak Formation in Labrud Section, Northern Damghan11184256110.22071/gsj.2015.42561FAB AghababalouPh. D. Student, Department of Geology, Islamic Azad University, Science and Research Branch, Tehran, Iran.Kh KhosrotehraniProfessor, Department of Geology, Islamic Azad University, Science and Research Branch, Tehran, IranS.M HoseininezhadAssistant Professor, Faculty of Earth Science, Damghan University, Damghan , IranJournal Article20120501The early Carboniferous Mobarak Formation is well exposed in the north of Damghan. It consists of fossiliferous limestone, marly limestone and grey shales. 31 species from 23 genera including: <em>Rossirhynchus adamantinus</em> (Gaetani, 1964), <em>Tomiproductus elegantulus</em> (Tolmmachev, 1924), <em>Pustula </em>cf<em>. altaica</em> (Tolmachev, 1924), <em>Leptagonia analoga</em> (Phillips, 1841), <em>Hemiplethrorhynchus crassus</em> (Gaetani, 1968)<em>, Tylothyris</em> cf.<em> planimedia</em> (Cvancara, 1958)<em>, Lamellosathyris </em>aff. <em>Lamellose</em> (Leveille, 1835)<em>,Punctospirifer </em>aff<em>. Scabricosta </em>(North, 1920) have been identified from the Labrud section. Four brachiopod assemblage zones show spanning from the Tournaisian to early Visean. The Mobarak Formation at this section overlies the Geirud Formation conformably and underlies the Dorud Formation(?) disconformably.The early Carboniferous Mobarak Formation is well exposed in the north of Damghan. It consists of fossiliferous limestone, marly limestone and grey shales. 31 species from 23 genera including: <em>Rossirhynchus adamantinus</em> (Gaetani, 1964), <em>Tomiproductus elegantulus</em> (Tolmmachev, 1924), <em>Pustula </em>cf<em>. altaica</em> (Tolmachev, 1924), <em>Leptagonia analoga</em> (Phillips, 1841), <em>Hemiplethrorhynchus crassus</em> (Gaetani, 1968)<em>, Tylothyris</em> cf.<em> planimedia</em> (Cvancara, 1958)<em>, Lamellosathyris </em>aff. <em>Lamellose</em> (Leveille, 1835)<em>,Punctospirifer </em>aff<em>. Scabricosta </em>(North, 1920) have been identified from the Labrud section. Four brachiopod assemblage zones show spanning from the Tournaisian to early Visean. The Mobarak Formation at this section overlies the Geirud Formation conformably and underlies the Dorud Formation(?) disconformably.http://www.gsjournal.ir/article_42561_042ee1919e19b83567c69716452a3d2e.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Biostratigraphy of Gurpi Formation Based on Calcareous Nannoplanktons in Gach and Kurdeh Anticline Sections (Lar Region)Biostratigraphy of Gurpi Formation Based on Calcareous Nannoplanktons in Gach and Kurdeh Anticline Sections (Lar Region)19264256210.22071/gsj.2015.42562FAN BadriPh.D., Geological Survey of Iran, Tehran, Iran.A.L KaniAssistant Professor, Department of Geology, Faculty of Earth Sciences, University of Shahid Beheshti, Tehran, Iran.Journal Article20110912The 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.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.http://www.gsjournal.ir/article_42562_4a6aae657b79fc79547e94da99ebc695.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Study of the Lithostratigraphy and Biostratigraphy of Ammonite Fauna of the Dalichai Formation at the Mahdishahr Section, N SemnanStudy of the Lithostratigraphy and Biostratigraphy of Ammonite Fauna of the Dalichai Formation at the Mahdishahr Section, N Semnan27384256310.22071/gsj.2015.42563FAT Sarbandi FarahaniM.Sc., Department of Geology, Faculty of Basic Sciences, Payam Noor University, Tehran, IranM.R MajidifardAssistant Professor, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, IranM.R Kebriaee- ZadehAssociated Professor, Faculty of Basic Sciences, Payam Noor University, Tehran, IranM MohammadiAssistant Professor, Department of Geology, Faculty of Basic Sciences, Payam Noor University, Tehran, IranJournal Article20120530The 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. 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. http://www.gsjournal.ir/article_42563_d6e789ae9b69bcc36374336cac7aea07.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Paleoecology of Aptian Gastropods in Bafgh Area, East of Yazd, IranPaleoecology of Aptian Gastropods in Bafgh Area, East of Yazd, Iran39444256510.22071/gsj.2015.42565FAH Karimian ZadeM.Sc., Department of Geology, Bahonar University, Kerman, IranM.R VaziriAssociate Professor, Department of Geology, Bahonar University, Kerman, IranA Lotf Abad ArabAssistance Professor, Department of Geology, Bahonar University, Kerman, IranJournal Article20120825In order to study the paleoecology of the Aptian gastropods, the Bafgh section with 380 meters thickness, in East of Yazd were studied in detail. In this region, a variety of different fossil groups, including macrofossils (gastropods, ammonites and echinoids) and microfossils (foraminifers and ostracods) are present and suggest an Aptian age for this section. 11 genus and species of gastropods are reported for the first time from this section. The microfossils and macrofossils assemblage all show a shallow environment with a suitable conditions for the time of sedimentation in the study area. In order to study the paleoecology of the Aptian gastropods, the Bafgh section with 380 meters thickness, in East of Yazd were studied in detail. In this region, a variety of different fossil groups, including macrofossils (gastropods, ammonites and echinoids) and microfossils (foraminifers and ostracods) are present and suggest an Aptian age for this section. 11 genus and species of gastropods are reported for the first time from this section. The microfossils and macrofossils assemblage all show a shallow environment with a suitable conditions for the time of sedimentation in the study area. http://www.gsjournal.ir/article_42565_01674b3b281fe29d292455098472213a.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Planktic Foraminiferal Palaeobathymetry of the Santonian-Campanian Boundary in Eastern Kopeh-Dagh Basin, Northeastern IranPlanktic Foraminiferal Palaeobathymetry of the Santonian-Campanian Boundary in Eastern Kopeh-Dagh Basin, Northeastern Iran45644257310.22071/gsj.2015.42573FAM Shafiee ArdestaniPh.D., Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, IranM VahidiniaAssociate Professor, Faculty of science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, IranA SadeghiAssociate Professor, Department of Geology, Faculty of Science, University of ShahidBeheshti, Tehran, IranJournal Article20120313In this research, we documented a paleontological study on the basis of planktic foraminifera, in five stratigraphic sections (Type, Padeha village, Shorab, Abderaz village and Qarehso) across the Santonian-Campanian transitional boundary in the eastern Kopeh-Dagh sedimentary basin. In all sections, no <em>M. testudinarius </em>Schlotheim (cosmopolitan species) was identified, which its last occurrence datum (LOD) is widely used to define the base of the Campanian stage. Several planktic foraminiferal biohorizons close to the Santonian/Campanian boundary were recorded, including the LOD’s of <em>Ventilabrella austiniana</em> Cushman, <em>Dicarinella concavata</em> (Brotzen) and <em>Dicarinella asymetrica </em>(Sigal), and the first occurrence datum (FOD) of<em> Contusotruncana patelliformis </em>(Gandolfi)<em>. </em>The Santonian/Campanian boundary was placed in the upper part of the <em>Dicarinella asymetrica</em> Total Range Zone at the top of the Abderaz Formation in the type section and other sections in Shorab, Abderaz village, Padeha village, and at the base of the Abtalkh Formation in the Qarehso section. The acquired bio-models for the study sections are quite comparable with that of Gale et al, 2008 in WDS section, North Texas. On the basis of quantitative analysis of the planktic and benthic foraminiferal assemblages, the sparse presence of keeled planktic foraminifera and planktic foraminifera (%P) indicates that a shallow marine condition was prevailing just above the Santonian/Campanian boundary in the type section, Shorab, Abderaz and Padeha village sections. In addition, the abundance of such foraminifera (keeled planktic foraminifera and planktic foraminifera) reflects deeper water depths in the Qarehso section at the same time. Besides, estimation of the planktic to benthic ratio, which is based on the Van der Zwaan equilibrium, confirms that in the base of Campanian at one of the study sections (Qarehso section) the water depth was 160 m. In this research, we documented a paleontological study on the basis of planktic foraminifera, in five stratigraphic sections (Type, Padeha village, Shorab, Abderaz village and Qarehso) across the Santonian-Campanian transitional boundary in the eastern Kopeh-Dagh sedimentary basin. In all sections, no <em>M. testudinarius </em>Schlotheim (cosmopolitan species) was identified, which its last occurrence datum (LOD) is widely used to define the base of the Campanian stage. Several planktic foraminiferal biohorizons close to the Santonian/Campanian boundary were recorded, including the LOD’s of <em>Ventilabrella austiniana</em> Cushman, <em>Dicarinella concavata</em> (Brotzen) and <em>Dicarinella asymetrica </em>(Sigal), and the first occurrence datum (FOD) of<em> Contusotruncana patelliformis </em>(Gandolfi)<em>. </em>The Santonian/Campanian boundary was placed in the upper part of the <em>Dicarinella asymetrica</em> Total Range Zone at the top of the Abderaz Formation in the type section and other sections in Shorab, Abderaz village, Padeha village, and at the base of the Abtalkh Formation in the Qarehso section. The acquired bio-models for the study sections are quite comparable with that of Gale et al, 2008 in WDS section, North Texas. On the basis of quantitative analysis of the planktic and benthic foraminiferal assemblages, the sparse presence of keeled planktic foraminifera and planktic foraminifera (%P) indicates that a shallow marine condition was prevailing just above the Santonian/Campanian boundary in the type section, Shorab, Abderaz and Padeha village sections. In addition, the abundance of such foraminifera (keeled planktic foraminifera and planktic foraminifera) reflects deeper water depths in the Qarehso section at the same time. Besides, estimation of the planktic to benthic ratio, which is based on the Van der Zwaan equilibrium, confirms that in the base of Campanian at one of the study sections (Qarehso section) the water depth was 160 m. http://www.gsjournal.ir/article_42573_098f8aee9ee74d3bfd11f8b61c129540.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Biozonation and Paleobathymetry of the Campanian -Maastrichtian Deposits Based on Planktonic Foraminifera in Jupar Section, Central IranBiozonation and Paleobathymetry of the Campanian -Maastrichtian Deposits Based on Planktonic Foraminifera in Jupar Section, Central Iran65724257610.22071/gsj.2015.42576FAB GhasemshiraziM. Sc., Department of Geology, Islamic Azad University, Science and Research Branch, Tehran, IranM.R MajidifardAssistant Professor, Research Institute for Earth Science, Geological Survey of Iran, Tehran, IranA KheradmandAssistant Professor, Department of Geology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, IranT MohtatPh. D., Geological Survey of Iran, Tehran, IranJournal Article20120909In this research, the Campanian -Maastrichtian deposits in Jupar section, Central Iran have been studied to determine biozonation and Paleobathymetry of the deposits. The planktonic and benthic foraminifera were studied in order to assign palaeobathymetry of the Campanian- Maastrichtian deposits. A depth of 490- 650 m was assigned for most parts of the sediments according to planktonic/epibenthic ratio and the regression equation D = e (3.58718+ (0.03534 × %P*)). In the present investigation, 58 planktonic species of 27 genera have been identified. The Campanian -Maastrichtian deposits is divided into 7 biozones on the basis of planktonic foraminifera, which are cosmopolitan and consist of biozone1-<em>Globotruncanita elevata </em>Partial Range Zone<em>, </em>Biozone2-<em> Globotruncana ventricosa</em> Interval Zone, Biozone3-<em> Globotruncanita calcarata </em>Interval Zone, Biozone4- <em>Globotruncanella havanensis </em>Partial range zone , Biozone5-<em> Globotruncana aegyptiaca </em>Interval zone<em>, </em> Biozone6-<em> Gansserina gansseri </em>Interval zone<em>, and</em> Biozone7-<em> Contusotruncana contusa</em> Interval Zone.In this research, the Campanian -Maastrichtian deposits in Jupar section, Central Iran have been studied to determine biozonation and Paleobathymetry of the deposits. The planktonic and benthic foraminifera were studied in order to assign palaeobathymetry of the Campanian- Maastrichtian deposits. A depth of 490- 650 m was assigned for most parts of the sediments according to planktonic/epibenthic ratio and the regression equation D = e (3.58718+ (0.03534 × %P*)). In the present investigation, 58 planktonic species of 27 genera have been identified. The Campanian -Maastrichtian deposits is divided into 7 biozones on the basis of planktonic foraminifera, which are cosmopolitan and consist of biozone1-<em>Globotruncanita elevata </em>Partial Range Zone<em>, </em>Biozone2-<em> Globotruncana ventricosa</em> Interval Zone, Biozone3-<em> Globotruncanita calcarata </em>Interval Zone, Biozone4- <em>Globotruncanella havanensis </em>Partial range zone , Biozone5-<em> Globotruncana aegyptiaca </em>Interval zone<em>, </em> Biozone6-<em> Gansserina gansseri </em>Interval zone<em>, and</em> Biozone7-<em> Contusotruncana contusa</em> Interval Zone.http://www.gsjournal.ir/article_42576_bc2d4e3cd7d945a7b1b2ab0fc7dc0f14.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Systematic and Paleoecology of Middle-Cretaceous Brachiopods of Family Sellithyrididae from Estakhrooyeh Section, West of KermanSystematic and Paleoecology of Middle-Cretaceous Brachiopods of Family Sellithyrididae from Estakhrooyeh Section, West of Kerman73804258310.22071/gsj.2015.42583FAF FoladiM.Sc. Lecturer, Department of Geology, Kerman Institute of Higher Education, Kerman, IranM DastanpourProfessor, Department of Geology, Kerman Institute of Higher Education, Kerman, IranJournal Article20120408In order to study of the systematic and paleoecology of Cretaceous (Aptian-Early cenomanian) Brachiopods, the Estakhrooyeh section in NW Baghin, west of Kerman City with 190 m in thickness was studied and sampled. The Middle part of this section contains diverse assemblages of macrofossils such as Brachiopods, Echinoderms, Gastropods, Bivalves and Corals. This biostratigraphic research resulted in to examine 5 genera and 10 species of brachiopoda of Sellithyrididae family for the first time from this section. The Brachiopods indicate Aptian-Early Cenomanian ages for these sediments. The Faunal assemblages suggest a shallow and suitable environment prevailed during the deposition of the strata. In order to study of the systematic and paleoecology of Cretaceous (Aptian-Early cenomanian) Brachiopods, the Estakhrooyeh section in NW Baghin, west of Kerman City with 190 m in thickness was studied and sampled. The Middle part of this section contains diverse assemblages of macrofossils such as Brachiopods, Echinoderms, Gastropods, Bivalves and Corals. This biostratigraphic research resulted in to examine 5 genera and 10 species of brachiopoda of Sellithyrididae family for the first time from this section. The Brachiopods indicate Aptian-Early Cenomanian ages for these sediments. The Faunal assemblages suggest a shallow and suitable environment prevailed during the deposition of the strata. http://www.gsjournal.ir/article_42583_79956d7ee5363d09af58b9cc81954160.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Palaeobathymetry of the Sarvak Formation in Well AZ 354 of Ahwaz Oil Field based on ForaminiferaPalaeobathymetry of the Sarvak Formation in Well AZ 354 of Ahwaz Oil Field based on Foraminifera81904258510.22071/gsj.2015.42585FAM.H KazemzadehPh.D. Student, Department of Geology, Faculty of Earth Science, Shahid Beheshti University of Tehran, IranE Ghasemi-NejadProfessor, Department of Geology, University College of Sciences, University of Tehran, Tehran, IranH Vaziri-MoghaddamProfessor, Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, IranJournal Article20120120The 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 <sup>(3.58718+(0.03534×%P)</sup>, 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). 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 <sup>(3.58718+(0.03534×%P)</sup>, 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). http://www.gsjournal.ir/article_42585_709f48233c9ce60d23b042ebabcca303.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Lithostratigraphy and Biostratigraphy of the Middle Part of the Shemshak Group at GolbiniSection Based on Ammonites, NE Jajarm, Eastern AlborzLithostratigraphy and Biostratigraphy of the Middle Part of the Shemshak Group at GolbiniSection Based on Ammonites, NE Jajarm, Eastern Alborz911004258610.22071/gsj.2015.42586FAZ KiadaliriM. Sc. Student, Islamic Azad University, Faculty of Sciences, North Tehran Brach, Tehran, IranM.R MajidifardAssistant Professor, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, IranJournal Article20120507The 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 (<em>Thouarsense</em>Zone, <em>Pseudoradiosa</em> Zone,<em>Aalensis</em> zone, <em>Opalinum</em> Zone, <em>Murchisonae</em>zone, <em>Concavum</em>Zone) 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.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 (<em>Thouarsense</em>Zone, <em>Pseudoradiosa</em> Zone,<em>Aalensis</em> zone, <em>Opalinum</em> Zone, <em>Murchisonae</em>zone, <em>Concavum</em>Zone) 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.http://www.gsjournal.ir/article_42586_30e95a9656bf6296d2b1358c4871a9c7.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Syetematic and Biostratigraphic Studies of Early Carboniferous Brachiopods in Abrendan Section, Damghan AreaSyetematic and Biostratigraphic Studies of Early Carboniferous Brachiopods in Abrendan Section, Damghan Area1011204258710.22071/gsj.2015.42587FAM Bahrammanesh TehraniPh.D., Geological Survey of Iran, Tehran, IranJournal Article20130109In this research, the brachiopod fauna from the Tournaisian (Early Carboniferous) Mobarak Formation located in the EasternAlborzMountains, North Iran have been analyzed. 745 specimens have been collected from the Abrendan section, located in north of the DamghanTown. The specimens classified into 36 species of 27 genera and 5 undetermined species and genera of 5 subfamilies in 8 orders: <em>Leptagonia analoga</em> (Phillips, 1836), Delepineineae gen et sp. Ind., <em>Geniculifera </em>sp. Ind., Dictyoclostinae gen et sp. Ind., <em>Geniculifera </em>sp. Ind., <em>Buxtonia </em>sp. Ind., <em>Marginatia vaughani </em>(Muir-Wood, 1928), <em>Marginatia </em>sp. Ind., <em>Tomiproductus elegantulus </em>(Tolmatchoff, 1924), Tolmatchoffini gen. Et. Sp. Ind., <em>Pustula </em>cf. <em>P. Altaica </em>Tolmatchoff, 1924, <em>Pustula </em>cf. <em>P. Kondomensis </em>Sarytcheva, 1963, <em>Pustula </em>spp., <em>Schellwienlla </em>sp. <em>A</em>, Derbyiidae gen. Et sp. Ind., <em>Rhipidomella michelini </em>(Léveillé, 1835), <em>Rhipidomella </em>sp. <em>A</em>, <em>Rhipidomella </em>sp. <em>B</em>, <em>Schizophoria (Schizophoria) resupinata </em>(Martin, 1809),<em>?Ptychomaletoechia </em>sp. Ind.,<em>Hemiplethorhynchus crassus </em>Gaetani, 1968, <em>Rossirhynchus adamantinus </em>Gaetani, 1964, <em>Paraphorhynchus </em>aff. <em>P. Elongatum </em>Weller, 1905, <em>Athyris </em>sp. Ind., <em>Cleiothyridina kusbassica </em>Beznosova in Sarytcheva et al., 1963, <em>Gerankalasiella</em> sp. Ind., <em>Composita megala </em>(Tolmatchoff, 1924), <em>Composita subquadrata </em>(Hall, 1858a), <em>Densalvus </em>sp. Ind., <em>Martinia </em>sp. Ind., <em>Ectochoristites </em>sp. Ind., Prospirinae gen. Et. Sp. Ind., <em>Athylopherous </em>sp. Ind., <em>Paralellora </em>sp. Ind., <em>Unispirifer (Unispirifer) striatoconvolutus </em>(Benson & Dun in Benson, Dun & Browne, 1920), <em>Unispirifer(Unispirifer) </em>sp. <em>A,</em> <em>Unispirifer (Unispirifer) </em>sp. <em>B</em>, <em>Imbrexia </em>sp. Ind., <em>Fusella </em>sp. Ind., <em>Syringothyris carteri </em>(Hall, 1857), <em>Syringothyris skinderi </em>Sokloskaja, 1963 in Sarytcheva et al., 1963, <em>Pseudosyrinx </em>sp. Ind. A species of Molusca Rostrochonca, <em>Hippocardia alborza</em> Hoare & Aghababalou, 2001 has been also found. The quantitative biostratigraphic analysis of the brachiopod assemblages bed by bed collected along the Abrendan section allowed the recognition of three concurrent range biozones: the <em>Schizophoria (S.) resupinata</em>-<em>Pseudosyrinx</em> sp. Ind. Biozone, the <em>Composita subquadrata-Geniculifera</em> sp. Ind. Biozone, and the <em>Cleiothyridina kusbassica</em>-<em>Unispirifer (U.) striatoconvolutus </em>biozone<em>.</em> Most of the brachiopod taxa in the biozones range from the Tournaisian to the Visean. However, some are restricted to the Tournaisian, confirming the age suggested by foraminifers in the upper part of the formation. The statistical and paleogeographical analysis show that the North Iran Brachiopods are mostly close to the coeval faunas from N America and Russia. This confirms the presence of an equatorial current flowing southeastward along the Gondwanan margin.In this research, the brachiopod fauna from the Tournaisian (Early Carboniferous) Mobarak Formation located in the EasternAlborzMountains, North Iran have been analyzed. 745 specimens have been collected from the Abrendan section, located in north of the DamghanTown. The specimens classified into 36 species of 27 genera and 5 undetermined species and genera of 5 subfamilies in 8 orders: <em>Leptagonia analoga</em> (Phillips, 1836), Delepineineae gen et sp. Ind., <em>Geniculifera </em>sp. Ind., Dictyoclostinae gen et sp. Ind., <em>Geniculifera </em>sp. Ind., <em>Buxtonia </em>sp. Ind., <em>Marginatia vaughani </em>(Muir-Wood, 1928), <em>Marginatia </em>sp. Ind., <em>Tomiproductus elegantulus </em>(Tolmatchoff, 1924), Tolmatchoffini gen. Et. Sp. Ind., <em>Pustula </em>cf. <em>P. Altaica </em>Tolmatchoff, 1924, <em>Pustula </em>cf. <em>P. Kondomensis </em>Sarytcheva, 1963, <em>Pustula </em>spp., <em>Schellwienlla </em>sp. <em>A</em>, Derbyiidae gen. Et sp. Ind., <em>Rhipidomella michelini </em>(Léveillé, 1835), <em>Rhipidomella </em>sp. <em>A</em>, <em>Rhipidomella </em>sp. <em>B</em>, <em>Schizophoria (Schizophoria) resupinata </em>(Martin, 1809),<em>?Ptychomaletoechia </em>sp. Ind.,<em>Hemiplethorhynchus crassus </em>Gaetani, 1968, <em>Rossirhynchus adamantinus </em>Gaetani, 1964, <em>Paraphorhynchus </em>aff. <em>P. Elongatum </em>Weller, 1905, <em>Athyris </em>sp. Ind., <em>Cleiothyridina kusbassica </em>Beznosova in Sarytcheva et al., 1963, <em>Gerankalasiella</em> sp. Ind., <em>Composita megala </em>(Tolmatchoff, 1924), <em>Composita subquadrata </em>(Hall, 1858a), <em>Densalvus </em>sp. Ind., <em>Martinia </em>sp. Ind., <em>Ectochoristites </em>sp. Ind., Prospirinae gen. Et. Sp. Ind., <em>Athylopherous </em>sp. Ind., <em>Paralellora </em>sp. Ind., <em>Unispirifer (Unispirifer) striatoconvolutus </em>(Benson & Dun in Benson, Dun & Browne, 1920), <em>Unispirifer(Unispirifer) </em>sp. <em>A,</em> <em>Unispirifer (Unispirifer) </em>sp. <em>B</em>, <em>Imbrexia </em>sp. Ind., <em>Fusella </em>sp. Ind., <em>Syringothyris carteri </em>(Hall, 1857), <em>Syringothyris skinderi </em>Sokloskaja, 1963 in Sarytcheva et al., 1963, <em>Pseudosyrinx </em>sp. Ind. A species of Molusca Rostrochonca, <em>Hippocardia alborza</em> Hoare & Aghababalou, 2001 has been also found. The quantitative biostratigraphic analysis of the brachiopod assemblages bed by bed collected along the Abrendan section allowed the recognition of three concurrent range biozones: the <em>Schizophoria (S.) resupinata</em>-<em>Pseudosyrinx</em> sp. Ind. Biozone, the <em>Composita subquadrata-Geniculifera</em> sp. Ind. Biozone, and the <em>Cleiothyridina kusbassica</em>-<em>Unispirifer (U.) striatoconvolutus </em>biozone<em>.</em> Most of the brachiopod taxa in the biozones range from the Tournaisian to the Visean. However, some are restricted to the Tournaisian, confirming the age suggested by foraminifers in the upper part of the formation. The statistical and paleogeographical analysis show that the North Iran Brachiopods are mostly close to the coeval faunas from N America and Russia. This confirms the presence of an equatorial current flowing southeastward along the Gondwanan margin.http://www.gsjournal.ir/article_42587_a046fdfa12c6ca29baf0529ab5331d7d.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Introduction, Taphonomy and Palaeoecology of late Aptian- Early Cenomanian Oysters (Family: Gryphaeidae), Basab Area, Northwest of KermanIntroduction, Taphonomy and Palaeoecology of late Aptian- Early Cenomanian Oysters (Family: Gryphaeidae), Basab Area, Northwest of Kerman1211324258810.22071/gsj.2015.42588FAL AsghariM.Sc, Department of Geology, Shahid Bahonar University of Kerman, Kerman, Iran.M.R VaziriAssociate Professor, Department of Geology, Shahid Bahonar University of Kerman, Kerman, Iran.A ArabAssistant Professor, Department of Geology, Shahid Bahonar University of Kerman, Kerman, Iran.Journal Article20120630The thick layers of late Aptian- early Cenomanian deposits in the northwest of Kerman, which consist of mainly marl and limestone has been sampled and studied. The thickness of the succession in the Basab area is 380 meters and is subdivided into 4 distinct and informal units that named Lower Basab Marl, Lower Basab Limestone, Upper Basab Marl and Upper Basab Limestone. The base of this section overlies paraconformably the Jurassic (Liassic) sandstones, while the upper boundary is an erosional surface and covered by the Neogene deposits. Among the macrofossil assemblages that found in this section, the Oysters that belong to three families of Gryphaeidae, Palaeolophidae and Ostreidae are more abundant. The Gryphaeidae family with 80% is more abundant than other families and discussed in this paper. Seven genera and species of this family are reported. Palaeoecological studies and taphonomy effects on the surface of specimens show a warm, shallow environment (intertidal and sublittoral) with a high energy during the deposition of the strata. The Oysters in studied area is very similar to those specimens reported from Egypt in the WadiQenaBasin.The thick layers of late Aptian- early Cenomanian deposits in the northwest of Kerman, which consist of mainly marl and limestone has been sampled and studied. The thickness of the succession in the Basab area is 380 meters and is subdivided into 4 distinct and informal units that named Lower Basab Marl, Lower Basab Limestone, Upper Basab Marl and Upper Basab Limestone. The base of this section overlies paraconformably the Jurassic (Liassic) sandstones, while the upper boundary is an erosional surface and covered by the Neogene deposits. Among the macrofossil assemblages that found in this section, the Oysters that belong to three families of Gryphaeidae, Palaeolophidae and Ostreidae are more abundant. The Gryphaeidae family with 80% is more abundant than other families and discussed in this paper. Seven genera and species of this family are reported. Palaeoecological studies and taphonomy effects on the surface of specimens show a warm, shallow environment (intertidal and sublittoral) with a high energy during the deposition of the strata. The Oysters in studied area is very similar to those specimens reported from Egypt in the WadiQenaBasin.http://www.gsjournal.ir/article_42588_6a4acd08ba53baa68893112d0accbb79.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Report of Jurassic Pantanellium Genus from Kermanshah Radiolarites, West IranReport of Jurassic Pantanellium Genus from Kermanshah Radiolarites, West Iran1331404259010.22071/gsj.2015.42590FAS.H VaziriProfessor, Department of Geology, Faculty of Basic Sciences, Islamic Azad University, North Tehran Branch, Tehran, IranM RamiPh.D., Department of Geology, Faculty of Basic Sciences, Islamic Azad University, North Tehran Branch, Tehran, IranA MatsoukaProfessor, Department of Geology, Faculty of Science, Niigata University, Niigata, JapanM.R MajidifardAssistant Professor, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, IranJournal Article20130205The Halashi 1 section in south of Kermanshah, West Iran with a thickness of 243 m consists of chert, limestone, mudstone, marlstone and shale and can be divided into 10 Beds/Bedsets. From the studied section, which led to identification the genus <em>Pantanellium</em> that is one of the most prolific genera among Mesozoic radiolarians, 143 samples were collected. In present study, five species including <em>Pantanellium whalenae, </em><em>Pantanellium </em>cf.<em> riedeli, </em><em>Pantanellium cumshewaense,</em><em>Pantanellium squinaboli</em> and<em>Pantanellium</em> cf. <em>lanceola</em> were identified that indicated an Early Tithonian age for the studied section. Identification of species is according to the pore frame number and the configuration, which are important criteria in the taxonomy of the family Pantanelliidae. The Halashi 1 section in south of Kermanshah, West Iran with a thickness of 243 m consists of chert, limestone, mudstone, marlstone and shale and can be divided into 10 Beds/Bedsets. From the studied section, which led to identification the genus <em>Pantanellium</em> that is one of the most prolific genera among Mesozoic radiolarians, 143 samples were collected. In present study, five species including <em>Pantanellium whalenae, </em><em>Pantanellium </em>cf.<em> riedeli, </em><em>Pantanellium cumshewaense,</em><em>Pantanellium squinaboli</em> and<em>Pantanellium</em> cf. <em>lanceola</em> were identified that indicated an Early Tithonian age for the studied section. Identification of species is according to the pore frame number and the configuration, which are important criteria in the taxonomy of the family Pantanelliidae. http://www.gsjournal.ir/article_42590_5494bdeb3a042c4c5e4992fe7cab03ae.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Biostratigraphy of Calcareous Nannofossils of Abtalkh Formation in the Eastern Kopet-Dagh Basin, Jalilabad (Southwest of Kalat) and Abtalkh Village (East of Mashhad) Stratigraphic SectionsBiostratigraphy of Calcareous Nannofossils of Abtalkh Formation in the Eastern Kopet-Dagh Basin, Jalilabad (Southwest of Kalat) and Abtalkh Village (East of Mashhad) Stratigraphic Sections1411544259910.22071/gsj.2015.42599FAF ForoughiPh.D. Student, Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, IranA Lotfali KaniAssistant Professor, Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, IranS GardinPh.D., Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements, UMR CNRS 7072, Université Pierre et Marie Curie, Paris 06, FranceM VahidiniaAssociate Professor, Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranJournal Article20130406The Kopet-Dagh basin is located in the northeast of Iran, in the triangle border of Iran, Turkmenistan and Afghanistan and consists of the marine Jurassic to Neogene strata. The Abtalkh Formation is one of the thickest lithostratigraphic upper Cretaceous units in the eastern Kopet-Dagh basin and is composed of light gray, green to bluish marl and silty marl. The Abtalkh Formation conformably overlies the Abderaz Formation, which contains marls and chalky limestones and is conformably overlain by the Nayzar Formation, which consists of sandstone, silty marl and limestone. The Abtalkh Formation contains very aboundant, rich and good to moderately preserved calcareous nannofossil assemblages of Tethyan realm. The total 220 samples in the jalilabad and 467 samples in the AbtalkhVillage stratigraphic sections, representing the oldest and youngest strata of upper Abderaz, Abtalkh and base of Nayzar successions, were collected. The thickness of Abtalkh Formation in the Jalilabad stratigraphic section is 1325.8m and for the AbtalkhVillage stratigraphic section is 1765m. One hundred sixteen nannoplanktonic species belonging to forty three genera and fifteen families were identified. The biostratigraphic study allowed the recognition of the calcareous nannofossil biozones of Sissingh (1977) emended by Perch-Nielsen (1985) and Burnett (1998). From bottom to top, part of CC19, CC20, CC21, CC22, part of CC23a biozones and UC14d<sup>TP</sup>, UC15b<sup>TP</sup>, UC15c<sup>TP</sup>, UC15d<sup>TP</sup> subzones and UC16 biozone were identified in the Jalilabad section. The Abtalkh Village section in the middle of eastern Kopet-Dagh basin is started with CC20 (UC15b<sup>TP</sup>) biozone and continued to CC23a (UC16) biozone. Nearly more than 30 calcareous nannofossil species were reported for the first time in Iran. The results of this study indicated that the age of Abtalkh Formation spans from early to uppermost Late Campanian for these two sections in the Kopet-Dagh basin.The Kopet-Dagh basin is located in the northeast of Iran, in the triangle border of Iran, Turkmenistan and Afghanistan and consists of the marine Jurassic to Neogene strata. The Abtalkh Formation is one of the thickest lithostratigraphic upper Cretaceous units in the eastern Kopet-Dagh basin and is composed of light gray, green to bluish marl and silty marl. The Abtalkh Formation conformably overlies the Abderaz Formation, which contains marls and chalky limestones and is conformably overlain by the Nayzar Formation, which consists of sandstone, silty marl and limestone. The Abtalkh Formation contains very aboundant, rich and good to moderately preserved calcareous nannofossil assemblages of Tethyan realm. The total 220 samples in the jalilabad and 467 samples in the AbtalkhVillage stratigraphic sections, representing the oldest and youngest strata of upper Abderaz, Abtalkh and base of Nayzar successions, were collected. The thickness of Abtalkh Formation in the Jalilabad stratigraphic section is 1325.8m and for the AbtalkhVillage stratigraphic section is 1765m. One hundred sixteen nannoplanktonic species belonging to forty three genera and fifteen families were identified. The biostratigraphic study allowed the recognition of the calcareous nannofossil biozones of Sissingh (1977) emended by Perch-Nielsen (1985) and Burnett (1998). From bottom to top, part of CC19, CC20, CC21, CC22, part of CC23a biozones and UC14d<sup>TP</sup>, UC15b<sup>TP</sup>, UC15c<sup>TP</sup>, UC15d<sup>TP</sup> subzones and UC16 biozone were identified in the Jalilabad section. The Abtalkh Village section in the middle of eastern Kopet-Dagh basin is started with CC20 (UC15b<sup>TP</sup>) biozone and continued to CC23a (UC16) biozone. Nearly more than 30 calcareous nannofossil species were reported for the first time in Iran. The results of this study indicated that the age of Abtalkh Formation spans from early to uppermost Late Campanian for these two sections in the Kopet-Dagh basin.http://www.gsjournal.ir/article_42599_e74e44a8d834301a8ab38120c1d885c5.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Planktonic Foraminiferal Biostratigraphy of Middle Albian to Cenomanian Strata in Kabir Kuh Anticline, Southeast of IlamPlanktonic Foraminiferal Biostratigraphy of Middle Albian to Cenomanian Strata in Kabir Kuh Anticline, Southeast of Ilam1551644260010.22071/gsj.2015.42600FAJ DaneshianAssociate Professor, Department of Geology, Faculty of Earth Sciences, Kharazmi University, Tehran, IranK YounesiM. Sc., Department of Geology, Faculty of Earth Sciences, Kharazmi University, Tehran. IranA AzadM. Sc., Department of Geology, Faculty of Earth Sciences, Kharazmi University, Tehran. IranS.A MoallemiAssistant Professor, Research Institute of Petroleum Industry, Tehran, IranJournal Article20111031Two 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 <em>Biticinella breggiensis </em>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<em> Ticinella roberti </em>Zone<em>, Ticinella primula</em> Zone<em>, Biticinella breggiensis</em> Zone<em>, Rotalipora ticinensis</em> Zone<em>, Paracostellagerina libyca</em> zone,<em> Microhedbergella rischi</em> zone<em>, Rotalipora cushmani</em> Zone<em>,Whiteinella archaeocretacea</em> Zone, several paraconformities have been recognized in the examined sections.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 <em>Biticinella breggiensis </em>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<em> Ticinella roberti </em>Zone<em>, Ticinella primula</em> Zone<em>, Biticinella breggiensis</em> Zone<em>, Rotalipora ticinensis</em> Zone<em>, Paracostellagerina libyca</em> zone,<em> Microhedbergella rischi</em> zone<em>, Rotalipora cushmani</em> Zone<em>,Whiteinella archaeocretacea</em> Zone, several paraconformities have been recognized in the examined sections.http://www.gsjournal.ir/article_42600_5443ed63377f9d36c01d80beb2527c67.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Paleoecology and Paleoenvironment of the Basal Purple Shales of the Pabdeh Formation at Bisheh-Deraz Section,
Southwest of IranPaleoecology and Paleoenvironment of the Basal Purple Shales of the Pabdeh Formation at Bisheh-Deraz Section,
Southwest of Iran1651724260110.22071/gsj.2015.42601FAJ Rabbani1Geology, Ferdowsi University of Mashhad, Mashhad, IranE Ghasemi-NejadProfessor, College of Science, Faculty of Geology, University of Tehran, Tehran, IranA.R AshouriProfessor, Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, IranM VahidiniaAssociate Professor, Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, IranJournal Article20120306The basal unit of the Pabdeh Formation at Bisheh-Deraz section composes of 47m purple to green to grey shale and marl. These beds gradually change to shale and argillaceous limestone in the top of the section. In order to study paleoecology and paleoenvironment of these beds, palynological evidences including palynofacies, abundance and diversity of dinocysts and environmental index have been investigated. Four Palynofacies types including IV: shelf to basin transition, VII-VIII: distal dysoxic-anoxic shelf, IX: distal suboxic-anoxic basin) have been differentiated that propose a distal suboxic-anoxic basin as depositional setting. According to the microfacies of planktonic foraminiferal Wakestone/Packestone a deep environment is proposed as the depositional basin. Using such parameters as palynofacies evidences, C/PPC ratio, AOM/MP ratio, abundance and diversity of dinocysts and environmental index, three system tracts related to one sequence (3<sup>rd</sup>order) with one sequence boundary type 2 and one maximum flooding surface have been determined. In general, the factors all together show a deepening upward trend through this rock unit.The basal unit of the Pabdeh Formation at Bisheh-Deraz section composes of 47m purple to green to grey shale and marl. These beds gradually change to shale and argillaceous limestone in the top of the section. In order to study paleoecology and paleoenvironment of these beds, palynological evidences including palynofacies, abundance and diversity of dinocysts and environmental index have been investigated. Four Palynofacies types including IV: shelf to basin transition, VII-VIII: distal dysoxic-anoxic shelf, IX: distal suboxic-anoxic basin) have been differentiated that propose a distal suboxic-anoxic basin as depositional setting. According to the microfacies of planktonic foraminiferal Wakestone/Packestone a deep environment is proposed as the depositional basin. Using such parameters as palynofacies evidences, C/PPC ratio, AOM/MP ratio, abundance and diversity of dinocysts and environmental index, three system tracts related to one sequence (3<sup>rd</sup>order) with one sequence boundary type 2 and one maximum flooding surface have been determined. In general, the factors all together show a deepening upward trend through this rock unit.http://www.gsjournal.ir/article_42601_7fca5382e22c011f5c2cabdc96378aeb.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220The Upper Triassic Sphinctozoan Sponges of the Howz-e Khan Member of the Nayband Formation, Southwest of Naybandan, East Central IranThe Upper Triassic Sphinctozoan Sponges of the Howz-e Khan Member of the Nayband Formation, Southwest of Naybandan, East Central Iran1731824260310.22071/gsj.2015.42603FAK RashidiAssistant Professor, Department of Geology, Payame Noor University, Tehran, IranB SaberzadehPh.D. Student, Ferdowsi University of Mashhad, International Campus, Mashhad, IranJournal Article20120703The Upper Triassic sediments in the Central Iran are known as Nayband Formation. They are a set of carbonatic and detritic sediments that can be divided into several members. The carbonatic Bidestan and Howz-e Khan members contain a diverse fauna and flora. In order to study and identify the taxonomic inventory of the Howz-e Khan member, two profiles were studied in the Naybandan area. The first one is located in southwest of Dig-e Rostam and the second one in southwest of the type locality, which were both sampled systematically. Moreover, unsystematic samples were taken from different parts of the area, which led to the recognition of various algae, foraminifera and sponges. This paper introduces the following sphinctozoan sponges: <em>Nevadathalamia variabilis</em>, <em>Amblysiphonella </em>sp., <em>Discosiphonella </em>sp., <em>Kashanella irregularis</em>, <em>Paradeningeria alpina</em>, <em>Tabasia maxima</em>, <em>Tabasia media</em>, and <em>Tabasia minima</em>.Thelithological and sedimentary structures as well as the microfacies indicate that the Howz-e Khan member has been formed in a shallow marine, near the coastal environment. These circumstances provided perfect conditions for patch-reef-forming organisms (here: sphinctozoan sponges) in the carbonates of the Howz-e Khan member. The Upper Triassic sediments in the Central Iran are known as Nayband Formation. They are a set of carbonatic and detritic sediments that can be divided into several members. The carbonatic Bidestan and Howz-e Khan members contain a diverse fauna and flora. In order to study and identify the taxonomic inventory of the Howz-e Khan member, two profiles were studied in the Naybandan area. The first one is located in southwest of Dig-e Rostam and the second one in southwest of the type locality, which were both sampled systematically. Moreover, unsystematic samples were taken from different parts of the area, which led to the recognition of various algae, foraminifera and sponges. This paper introduces the following sphinctozoan sponges: <em>Nevadathalamia variabilis</em>, <em>Amblysiphonella </em>sp., <em>Discosiphonella </em>sp., <em>Kashanella irregularis</em>, <em>Paradeningeria alpina</em>, <em>Tabasia maxima</em>, <em>Tabasia media</em>, and <em>Tabasia minima</em>.Thelithological and sedimentary structures as well as the microfacies indicate that the Howz-e Khan member has been formed in a shallow marine, near the coastal environment. These circumstances provided perfect conditions for patch-reef-forming organisms (here: sphinctozoan sponges) in the carbonates of the Howz-e Khan member. http://www.gsjournal.ir/article_42603_ff6b7e7f28b96c5c26bf3819cae91f81.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Determination of Sedimentation Rate and Verification of Holocene Sediments in Northeastern Part of the Persian Gulf: ACase Study in Southern Bandar AbbasDetermination of Sedimentation Rate and Verification of Holocene Sediments in Northeastern Part of the Persian Gulf: ACase Study in Southern Bandar Abbas1831924260810.22071/gsj.2015.42608FAR LakAssistant Professor, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, IranM TaghizadehPh.D., Petro Gohar Farasahel Kish Co., Tehtan, IranJournal Article20110626The Persian Gulf has an area about 240000 km2, considered as the northern part of the counterclockwise movement of Arabian Plate and as a recent example of Holocene carbonated sedimentary environment in dry (arid) climate. The basin volume, regarding to its average depth (36m), is estimated about 87,000km3. The present study was done in order to examine the sea level changes and determine the rate of sedimentation of Holocene deposits in the northeast of Persian Gulf. A complete and undisturbed core from the Holocene deposits (1070 cm length) located in the south of Rajaee port in theHormozgan province was prepared. Following the exact description of this core, based on the objective observations, 52 samples were taken according to the facies divisions and they were sedimentologically and geochemically tested. The granulometric analysis, mineralogy by XRD method, abundance percentage of elements by ICP-OEC device and polarograph, percentage of organic matter by the Rock Eval device, percentage determination of carbonates by automatic calcimeter device were done for all samples and 10 samples were dated by <sup>14</sup>C AMS method. The granulometric results indicated that most of the deposits are mud containing sand and gravel. The gravels are mainly related to shell fragments. The amount of carbonates varies from 17 to 84 percent. The silisiclastic deposits include quartz, feldspar, muscovite, pyroxene and clay minerals such as kaolinite, chlorite, montmoryonite, illite and paligorskite. The chemical and biochemical sediments are mainly calcite, dolomite and aragonite. The percentage of organic matter contained in the sediments varies from 0.02 to 0.13. The variation curve of calcium and strontium, which indicates intrabasinal sediments, is correlated to sea level changes in combination with objective evidences such as grain size, sediment type, and amount of organic matter, texture and structure of sediments. The abundance of most elements especially Al, Mg, Mn, Cr, Ba with continental origin, revealed a reversed relation with the sea level variations. In addition, two significant phases of rapid transgression have occurred from 6800 to 3700 and from 9300 to 7900 years ago. The dating results showed that the average rate of sedimentation in the study area is about 1mmper year(966mm/ka).The Persian Gulf has an area about 240000 km2, considered as the northern part of the counterclockwise movement of Arabian Plate and as a recent example of Holocene carbonated sedimentary environment in dry (arid) climate. The basin volume, regarding to its average depth (36m), is estimated about 87,000km3. The present study was done in order to examine the sea level changes and determine the rate of sedimentation of Holocene deposits in the northeast of Persian Gulf. A complete and undisturbed core from the Holocene deposits (1070 cm length) located in the south of Rajaee port in theHormozgan province was prepared. Following the exact description of this core, based on the objective observations, 52 samples were taken according to the facies divisions and they were sedimentologically and geochemically tested. The granulometric analysis, mineralogy by XRD method, abundance percentage of elements by ICP-OEC device and polarograph, percentage of organic matter by the Rock Eval device, percentage determination of carbonates by automatic calcimeter device were done for all samples and 10 samples were dated by <sup>14</sup>C AMS method. The granulometric results indicated that most of the deposits are mud containing sand and gravel. The gravels are mainly related to shell fragments. The amount of carbonates varies from 17 to 84 percent. The silisiclastic deposits include quartz, feldspar, muscovite, pyroxene and clay minerals such as kaolinite, chlorite, montmoryonite, illite and paligorskite. The chemical and biochemical sediments are mainly calcite, dolomite and aragonite. The percentage of organic matter contained in the sediments varies from 0.02 to 0.13. The variation curve of calcium and strontium, which indicates intrabasinal sediments, is correlated to sea level changes in combination with objective evidences such as grain size, sediment type, and amount of organic matter, texture and structure of sediments. The abundance of most elements especially Al, Mg, Mn, Cr, Ba with continental origin, revealed a reversed relation with the sea level variations. In addition, two significant phases of rapid transgression have occurred from 6800 to 3700 and from 9300 to 7900 years ago. The dating results showed that the average rate of sedimentation in the study area is about 1mmper year(966mm/ka).http://www.gsjournal.ir/article_42608_385bdceb491a089308cc87b5f27ec15e.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Mineralogy, Origin and Distribution of Clay in the Meyghan Playa, ArakMineralogy, Origin and Distribution of Clay in the Meyghan Playa, Arak1932024261210.22071/gsj.2015.42612FAL AbdiM. Sc., School of Geology, University College of Science, Tehran University, Tehran, IranH Rahimpour-BonabProfessor., School of Geology, University College of Science, Tehran University, Tehran, IranJournal Article20110808The Meyghan Playa is an inland closed basin, which is located in center of the aquifer Arak plain. This playa is a seasonal lake and from hydrological point of view acts as erosional base level of region and is appropriate site for precipitation clastic and chemical deposits. For mineralogical and sedimentological investigations 94 sediment samples were collected from the playa. 19 samples from surface sediments in transect to the center of playa and 31 specimens from 7 cores were systematically collected and studied by X-ray diffraction (XRD) technique. The clay minerals include Illite, Chlorite, Kaolinite,Vermiculite and Smectite. Illite and Chlorite are the most important clay minerals in the playa. Origins of clay minerals in the Meyghan playa are generally detrital, occurred by physical weathering and indicate composition of bed rock. The study of surface sediments indicate that amount of clay minerals from margin to center of the playa such as another detrital mineral (Quartz) is decreased. In addition, amount of them towards depth is increased. Therefore it shows the presence of a high water level and cold - humid climate in the past (late Pleistocene).The Meyghan Playa is an inland closed basin, which is located in center of the aquifer Arak plain. This playa is a seasonal lake and from hydrological point of view acts as erosional base level of region and is appropriate site for precipitation clastic and chemical deposits. For mineralogical and sedimentological investigations 94 sediment samples were collected from the playa. 19 samples from surface sediments in transect to the center of playa and 31 specimens from 7 cores were systematically collected and studied by X-ray diffraction (XRD) technique. The clay minerals include Illite, Chlorite, Kaolinite,Vermiculite and Smectite. Illite and Chlorite are the most important clay minerals in the playa. Origins of clay minerals in the Meyghan playa are generally detrital, occurred by physical weathering and indicate composition of bed rock. The study of surface sediments indicate that amount of clay minerals from margin to center of the playa such as another detrital mineral (Quartz) is decreased. In addition, amount of them towards depth is increased. Therefore it shows the presence of a high water level and cold - humid climate in the past (late Pleistocene).http://www.gsjournal.ir/article_42612_2d221e11ecd5669f53a2a852581b4cd2.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Study of Original Carbonate Mineralogy of the Nayband Formation Using Geochemical Evidences in Darbidkhoon, Tarz, Gitry and Kuhbanan Stratigraphic Sections, SE of IranStudy of Original Carbonate Mineralogy of the Nayband Formation Using Geochemical Evidences in Darbidkhoon, Tarz, Gitry and Kuhbanan Stratigraphic Sections, SE of Iran2032164261610.22071/gsj.2015.42616FAZ KalantarzadehPh.D. Student, Department of Geology, Islamic Azad University, Science and Research Branch, Tehran, Iran.M.H AdabiProfessor, Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran.H Rahimpour BonabAssociate Professor, Department of Geology, Faculty of Sciences, Tehran University, Tehran, Iran.Journal Article20111212After Early Cimmerian orogenic stage, due to marine transgression, the Nayband Formation Norian_Rethian (Upper Triassic) in age deposited in the Central Iran Zone. Because of transforming of aragonite and high Mg calcite into low Mg calcite during diagenesis, recognition of original carbonate mineralogy based on petrographic studies is difficult. In this research, original carbonate mineralogy and type of carbonates (tropical, temperate and polar) of the Nayband Formation in Darbidkhoon, Tarz, Gitry and Kuhbanan stratigraghic sections have been studied using geochemical evidences. The trace elements (Na, Sr, Fe, Mn) and isotopes (and) data of the Nayband Formation carbonates is located inside or close to the aragonitic tropical Fahlian Formation (Lower Cretaceous), the Ilam Formation (Upper Cretaceous), the Kangane Formation (Lower Triassic) and the Mozduran Formation (Upper Jurassic) limestones, because of aragonitic original carbonate mineralogy. The results of elemental and isotopic analysis correlate with the petrographic evidences and paleogeographic map of the Upper Triassic. After Early Cimmerian orogenic stage, due to marine transgression, the Nayband Formation Norian_Rethian (Upper Triassic) in age deposited in the Central Iran Zone. Because of transforming of aragonite and high Mg calcite into low Mg calcite during diagenesis, recognition of original carbonate mineralogy based on petrographic studies is difficult. In this research, original carbonate mineralogy and type of carbonates (tropical, temperate and polar) of the Nayband Formation in Darbidkhoon, Tarz, Gitry and Kuhbanan stratigraghic sections have been studied using geochemical evidences. The trace elements (Na, Sr, Fe, Mn) and isotopes (and) data of the Nayband Formation carbonates is located inside or close to the aragonitic tropical Fahlian Formation (Lower Cretaceous), the Ilam Formation (Upper Cretaceous), the Kangane Formation (Lower Triassic) and the Mozduran Formation (Upper Jurassic) limestones, because of aragonitic original carbonate mineralogy. The results of elemental and isotopic analysis correlate with the petrographic evidences and paleogeographic map of the Upper Triassic. http://www.gsjournal.ir/article_42616_b1412cac3d03fd2b16448d1e33e96cf4.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Geochemical Changing of the Devonian–Carboniferous Transition in the Labnesar Section, N Damghan, IranGeochemical Changing of the Devonian–Carboniferous Transition in the Labnesar Section, N Damghan, Iran2172284262110.22071/gsj.2015.42621FAK MohammadiM.Sc., Faculty of Earth Sciences, Damghan University, Damghan, IranN TaghipourAssistant Professor, Faculty of Earth Sciences, Damghan University, Damghan, IranH Mosaddegh] Associate Professor, Faculty of Earth Sciences, Damghan University, Damghan, IranJournal Article20120716Due to some environmental variations such as sea level fluctuation and the Hangenberg mass extinction event, geochemical variations of elements have occurred in the Devonian-Carboniferous transition, which some of these elements are useful indicators to display the source of sediments and the sea level changes. In this transition, Sr is one of these elements has a reverse relation with sea level changing and a direct relation with amount of sediment deposition. Trace elements such as Sr, Fe, Mn, Mg, Al, and Ca display the depositional environment conditions and their changing is affected by indoor and outdoor environmental conditions such as pH, Eh, climate, etc. This study has focused on investigation of elemental changes at the Devonian-Carboniferous boundary in the Khoshyeilagh and Mobarak Formations in the Labnesar section, North of Damghan.
The elemental changing in Brachiopoda shells and its containing sediments has the same trend as they show the fossil samples are <em>in situ</em>. The environmental situation of fossil organisms and their involving sediments in the study section were semi close to open sea with anoxia conditions. The black shale at D-C boundary shows LREE richer than HREE that confirmed its continental source. The variation of some elements such as Mn, Fe, Na… at D-C boundary in the Labnesar section indicates of LMC (low magnesium calcite) in the Brachiopod shells and involving sediments. The quantity variations of Mn and Sr in D-C boundary are related to sea level fluctuations. These elements are influenced by the sea level changes and impress the amount of other elements such as Fe, Al, Ti, Mg, Ca, Na, and K. The median amount of Na at the boundary indicates a moderate salinity. Due to some environmental variations such as sea level fluctuation and the Hangenberg mass extinction event, geochemical variations of elements have occurred in the Devonian-Carboniferous transition, which some of these elements are useful indicators to display the source of sediments and the sea level changes. In this transition, Sr is one of these elements has a reverse relation with sea level changing and a direct relation with amount of sediment deposition. Trace elements such as Sr, Fe, Mn, Mg, Al, and Ca display the depositional environment conditions and their changing is affected by indoor and outdoor environmental conditions such as pH, Eh, climate, etc. This study has focused on investigation of elemental changes at the Devonian-Carboniferous boundary in the Khoshyeilagh and Mobarak Formations in the Labnesar section, North of Damghan.
The elemental changing in Brachiopoda shells and its containing sediments has the same trend as they show the fossil samples are <em>in situ</em>. The environmental situation of fossil organisms and their involving sediments in the study section were semi close to open sea with anoxia conditions. The black shale at D-C boundary shows LREE richer than HREE that confirmed its continental source. The variation of some elements such as Mn, Fe, Na… at D-C boundary in the Labnesar section indicates of LMC (low magnesium calcite) in the Brachiopod shells and involving sediments. The quantity variations of Mn and Sr in D-C boundary are related to sea level fluctuations. These elements are influenced by the sea level changes and impress the amount of other elements such as Fe, Al, Ti, Mg, Ca, Na, and K. The median amount of Na at the boundary indicates a moderate salinity. http://www.gsjournal.ir/article_42621_18fb8e00d9d9713ca7fd80691c16c641.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220The Study of Role and Texture of Anhydrite in Production Zone of Asmari Formation in Mansuri Oil Field, Zagros, IranThe Study of Role and Texture of Anhydrite in Production Zone of Asmari Formation in Mansuri Oil Field, Zagros, Iran2032164265910.22071/gsj.2015.42659FAM Kavianpor SangnoM.Sc., Faculty of Basic Sciences, Department of Geology, Ferdowsi University of Mashhad, Mashhad, IranA NamdarianM.Sc., Faculty of Basic Sciences, Department of Geology, Ferdowsi University of Mashhad, Mashhad, IranS.R Mousavi-HaramiProfessor, Faculty of Basic Sciences, Department of Geology, Ferdowsi University of Mashhad, Mashhad, IranA MahboubiProfessor, Faculty of Basic Sciences, Department of Geology, Ferdowsi University of Mashhad, Mashhad, IranA OmidpourPh.D. Student, Department of Geology, National Iranian South Oil Company, Ahvaz, IranJournal Article20120408Evaporites include wide range of chemical deposits, which are precipitated in surface or near surface, from the concentrated brine by evaporation. Diagenetic processes are important factors can effect on reservoir quality. The Oligo-Miocene Asmari reservoir comprise of siliciclastic and carbonate sequences in the Mansouri Oil Field and reservoir quality of these rocks are affected by diagenetic processes during the time. One of the most important processes is anhydrite cement, which spread as layer, poikilotopic, pores filler and pervasive, early nodular, nodular- burial, scattered crystals, fracture and vein filler in the reservoir. Spread of anhydrite cement has a negative impact on the reservoir quality. On the other hand, the higher solubility of anhydrite cement than carbonate cement can have a positive effect on the reservoir quality. The Interplay of digenetic processes and anhydrite texture is visible in increasing or decreasing of characteristics of the Asmari reservoir. The result of this study shows that anhydrite (during diagenesis) as a cement with poikilotopic fabric and pervasive texture of porosity filler has the most important role in reduction of reservoir quality, but the processes such as dissolution has the main role in increasing of reservoir quality of the Asmari Formation in the Mansouri Oil Field. Evaporites include wide range of chemical deposits, which are precipitated in surface or near surface, from the concentrated brine by evaporation. Diagenetic processes are important factors can effect on reservoir quality. The Oligo-Miocene Asmari reservoir comprise of siliciclastic and carbonate sequences in the Mansouri Oil Field and reservoir quality of these rocks are affected by diagenetic processes during the time. One of the most important processes is anhydrite cement, which spread as layer, poikilotopic, pores filler and pervasive, early nodular, nodular- burial, scattered crystals, fracture and vein filler in the reservoir. Spread of anhydrite cement has a negative impact on the reservoir quality. On the other hand, the higher solubility of anhydrite cement than carbonate cement can have a positive effect on the reservoir quality. The Interplay of digenetic processes and anhydrite texture is visible in increasing or decreasing of characteristics of the Asmari reservoir. The result of this study shows that anhydrite (during diagenesis) as a cement with poikilotopic fabric and pervasive texture of porosity filler has the most important role in reduction of reservoir quality, but the processes such as dissolution has the main role in increasing of reservoir quality of the Asmari Formation in the Mansouri Oil Field. http://www.gsjournal.ir/article_42659_94659b4528d7d3d4fe1203b82ae8aca5.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Sedimentary Facies and Sequence Stratigraphy of Qom Formation Deposits in NE Delijan,NW Central IranSedimentary Facies and Sequence Stratigraphy of Qom Formation Deposits in NE Delijan,NW Central Iran2292364266310.22071/gsj.2015.42663FAM KaravanM. Sc., Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranA MahboubiProfessor, Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranH Vaziri-MoghaddamProfessor, Department of Geology, University of Esfahan, Esfahan, IranR Moussavi-HaramiProfessor, Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranJournal Article20120129The Oligocene Qom Formation deposits in NW Central Iran (NE Delijan) are widespread in NE-SW trend.Four members of the Qom Formation (unknown, a, b& c<sub>1</sub>) in the study area consist of mainly marly limestone, limestone, sandy limestone and a minor amounts of sandstone. It disconformablyoverliesthe Lower Red Formation and the upper boundary is covered by the recent alluvium. Based on the benthic foraminifers assemblage, these deposits are attributed to Oligocene (Rupelian- Chattian). Petrographic considerationled to identification of 12 carbonatemicrofacies and one sandstone facies that may have been deposited in a homoclinal ramp and in 4 sub environments including tidal flat, lagoon, bioclastic bar and open marine. Sequence stratigraphy analysis led to identification of 8 3rdordersdepositional sequences bounded by type I and type II sequence boundaries. Comparison between interpreted relative sea level curve with global sea level curve showsreasonable correlation with the lower and upper sequence boundaries of this formation and also Rupelian- Chattianboundary and the differences in other sequence boundaries can be related to local tectonic activity in the sedimentary basin of Qom Formation and the local sea level changes.The Oligocene Qom Formation deposits in NW Central Iran (NE Delijan) are widespread in NE-SW trend.Four members of the Qom Formation (unknown, a, b& c<sub>1</sub>) in the study area consist of mainly marly limestone, limestone, sandy limestone and a minor amounts of sandstone. It disconformablyoverliesthe Lower Red Formation and the upper boundary is covered by the recent alluvium. Based on the benthic foraminifers assemblage, these deposits are attributed to Oligocene (Rupelian- Chattian). Petrographic considerationled to identification of 12 carbonatemicrofacies and one sandstone facies that may have been deposited in a homoclinal ramp and in 4 sub environments including tidal flat, lagoon, bioclastic bar and open marine. Sequence stratigraphy analysis led to identification of 8 3rdordersdepositional sequences bounded by type I and type II sequence boundaries. Comparison between interpreted relative sea level curve with global sea level curve showsreasonable correlation with the lower and upper sequence boundaries of this formation and also Rupelian- Chattianboundary and the differences in other sequence boundaries can be related to local tectonic activity in the sedimentary basin of Qom Formation and the local sea level changes.http://www.gsjournal.ir/article_42663_63983310d38ab66a2c077499cea3978a.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Lithofacies and Depositional Environment of the Early Jurassic
Ab-Haji Formation in Outcrop and Exploration
Boreholes of Parvadeh Coal Mine, Tabas, East Central IranLithofacies and Depositional Environment of the Early Jurassic
Ab-Haji Formation in Outcrop and Exploration
Boreholes of Parvadeh Coal Mine, Tabas, East Central Iran2492624266510.22071/gsj.2015.42665FAM.A SalehiPh.D. Student, Department of Geology, Faculty of Basic Sciences, Ferdowsi University of Mashhad, Mashhad, IranS.R Mousavi-HaramiProfessor, Department of Geology, Faculty of Basic Sciences, Ferdowsi University of Mashhad, Mashhad, IranA MahboubiProfessor, Department of Geology, Faculty of Basic Sciences, Ferdowsi University of Mashhad, Mashhad, IranB RahimiAssociate Professor, Department of Geology, Faculty of Basic Sciences, Ferdowsi University of Mashhad, Mashhad, IranJournal Article20120815The Lower Jurassic Ab-Haji Formation consists of siliciclastic sediments, which are widely exposed in the Tabas Block. This formation varies in thickness from tens of meters to more than 500 m in northern Tabas Block. The Ab-Haji Formation with avearge thickness of 75 meters presents in the Tabas Coal Mine area and consists mainly of sandstone, siltstone, claystone with a few thin interbeds of coal seams. Two outcrops and three exploration boreholes were studied in order to identify lithofacies and to interpret the depositional environment. The lithofacies analysis in outcrops imply two siliciclastic coarse grained (Gcm, Gt), four medium grained (St, Sp, Sr, Sh), two fine grained (Fl, Fm) and one coal lithofacies. Identified lithofacies can be grouped into four architectural elements including channel, point bar, crevasse splay and coastal plain swamps. The electorofacies and log motif analysis led to recognition and differentiation of architectural elements in exploration boreholes. The lithofacies and architectural elements show that the siliciclastic sediments of the Ab-Haji Formation were deposited in the meandering river system within a coastal plain with widespread swamps. The sedimentological analysis led to reconstruction of paleogeography in eastern part of the Tabas Block, which shows deposition of nonmarine to coastal plain environment in this part of the block.The Lower Jurassic Ab-Haji Formation consists of siliciclastic sediments, which are widely exposed in the Tabas Block. This formation varies in thickness from tens of meters to more than 500 m in northern Tabas Block. The Ab-Haji Formation with avearge thickness of 75 meters presents in the Tabas Coal Mine area and consists mainly of sandstone, siltstone, claystone with a few thin interbeds of coal seams. Two outcrops and three exploration boreholes were studied in order to identify lithofacies and to interpret the depositional environment. The lithofacies analysis in outcrops imply two siliciclastic coarse grained (Gcm, Gt), four medium grained (St, Sp, Sr, Sh), two fine grained (Fl, Fm) and one coal lithofacies. Identified lithofacies can be grouped into four architectural elements including channel, point bar, crevasse splay and coastal plain swamps. The electorofacies and log motif analysis led to recognition and differentiation of architectural elements in exploration boreholes. The lithofacies and architectural elements show that the siliciclastic sediments of the Ab-Haji Formation were deposited in the meandering river system within a coastal plain with widespread swamps. The sedimentological analysis led to reconstruction of paleogeography in eastern part of the Tabas Block, which shows deposition of nonmarine to coastal plain environment in this part of the block.http://www.gsjournal.ir/article_42665_2bf83ef8ef1ddeec834349fd4a9b42b7.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Sedimentary Environment, Diagenesis and Sequence Stratigraphy of Upper Sarvak Formation (Mishrif Equivalent) in Siri Oil FieldsSedimentary Environment, Diagenesis and Sequence Stratigraphy of Upper Sarvak Formation (Mishrif Equivalent) in Siri Oil Fields2632744266610.22071/gsj.2015.42666FAM KhanjaniPh.D., Department of Geology, Science and Research Branch, Islamic Azad University (IAU), Tehran, IranS.R Moussavi-HaramiProfessor, Department of Geology, Faculty of Basic Science, Ferdowsi University of Mashhad, Mashhad, IranH Rahimpour-BonabProfessor, Department of Geology, College of Science, University of Tehran, Tehran , IranM.R KamaliAssociate Professor, Exploration and Production Division, Research Institute of Petroleum Industry (RIPI), Tehran, IranJournal Article20130108The Albian - Turonian Sarvak Formation, the second major reservoir formation in south and southwest Iran is composed of mainly carbonate rocks. In this study, the upper part of Sarvak Formation in Siri Oil Fields was studied to determine facies, depositional environments, diagenetic processes and sequence stratigraphy analysis. The facies analysis led to the recognition of 12 microfacies in 5 facies associations, which deposited in a homoclinal carbonate ramp environment. The main diagenetic processes affected carbonates of this formation are bioturbation, micritization, cementation, dissolution, dolomitization, stylolitization, pyritization and fracturing. The most important cements in this formation are fine equant calcite cement, drusy mosaic calcite cement, coarse blocky calcite cement and syntaxial calcite overgrowth cement. Three third order sequences recognized in sequence stratigraphic studies for the upper part of Sarvak Formation taking into account of facies and diagenetic events in a sequence stratigraphic framework.The Albian - Turonian Sarvak Formation, the second major reservoir formation in south and southwest Iran is composed of mainly carbonate rocks. In this study, the upper part of Sarvak Formation in Siri Oil Fields was studied to determine facies, depositional environments, diagenetic processes and sequence stratigraphy analysis. The facies analysis led to the recognition of 12 microfacies in 5 facies associations, which deposited in a homoclinal carbonate ramp environment. The main diagenetic processes affected carbonates of this formation are bioturbation, micritization, cementation, dissolution, dolomitization, stylolitization, pyritization and fracturing. The most important cements in this formation are fine equant calcite cement, drusy mosaic calcite cement, coarse blocky calcite cement and syntaxial calcite overgrowth cement. Three third order sequences recognized in sequence stratigraphic studies for the upper part of Sarvak Formation taking into account of facies and diagenetic events in a sequence stratigraphic framework.http://www.gsjournal.ir/article_42666_b1099dbf2b6fee3719137de6d20cd5be.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220The Effect of Sea Level Change on Depositional Facies in Mozduran Formation, West of the Kopet-Dagh BasinThe Effect of Sea Level Change on Depositional Facies in Mozduran Formation, West of the Kopet-Dagh Basin2752864266910.22071/gsj.2015.42669FAS.Z PourheidarM. Sc. Student, Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranA MahboubiProfessor, Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranM.H Mahmudy GharaieAssistant Professor, Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranS.R Moussavi HaramiProfessor, Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranJournal Article20130101The Mozduran Formation in west of the Kopet-Dagh basin, NE Jajarm, is mainly composed of dolostone in top and base, and mudstone to grainstone limestones in the middle parts of Cheshme-Khan section. This formation in the Qezel-Tapeh2 well is composed of alternative limestone and shale layers. Based on the facies studies, four carbonate facies associations (open marine, barrier, lagoon and tidal flat) have been identified, including fifteen carbonate microfacies and two siliciclastic lithofacies. It is interpreted that the Mozduran Formation in this area were deposited in a homoclinal ramp of a carbonate platform. The sequence stratigraphy analysis led to distinguish five depositional sequences in the Cheshme-Khan section and four depositional sequences in the Qezel-Tapeh2 well. The lower boundary of the 1st sequence (paleosol layar in the Cheshme-Khan section) and the upper boundary of the latest sequence (continental deposits) of both sections are a "type 1" sequence boundaries, but other boundaries are interpreted to be a "type 2" sequence boundaries. The relative sea-level curve of the study area comparing to the global sea-level curve, shows a relatively correlation and some differences can probably be related to regional tectonic setting of the Kopet-Dagh basin due to subsidence along the longitudinal faults and sediment loading. The Mozduran Formation in west of the Kopet-Dagh basin, NE Jajarm, is mainly composed of dolostone in top and base, and mudstone to grainstone limestones in the middle parts of Cheshme-Khan section. This formation in the Qezel-Tapeh2 well is composed of alternative limestone and shale layers. Based on the facies studies, four carbonate facies associations (open marine, barrier, lagoon and tidal flat) have been identified, including fifteen carbonate microfacies and two siliciclastic lithofacies. It is interpreted that the Mozduran Formation in this area were deposited in a homoclinal ramp of a carbonate platform. The sequence stratigraphy analysis led to distinguish five depositional sequences in the Cheshme-Khan section and four depositional sequences in the Qezel-Tapeh2 well. The lower boundary of the 1st sequence (paleosol layar in the Cheshme-Khan section) and the upper boundary of the latest sequence (continental deposits) of both sections are a "type 1" sequence boundaries, but other boundaries are interpreted to be a "type 2" sequence boundaries. The relative sea-level curve of the study area comparing to the global sea-level curve, shows a relatively correlation and some differences can probably be related to regional tectonic setting of the Kopet-Dagh basin due to subsidence along the longitudinal faults and sediment loading. http://www.gsjournal.ir/article_42669_94f910b4ff4ce742da2ed306529134bd.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Mineralogy and Geochemistry of the Neoproterozoic Kahar Formation Mudrocks, Kahar Mountain, NW of TehranMineralogy and Geochemistry of the Neoproterozoic Kahar Formation Mudrocks, Kahar Mountain, NW of Tehran2872994272910.22071/gsj.2015.42729FAN Etemad-SaeedPh.D. Student, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran0000-0001-5071-6283M Hosseini-BarziAssistant Professor, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, IranM.H AdabiProfessor, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, IranA SadeghiAssociate Professor, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, IranJournal Article20130715The Kahar Formation at its type locality in the KaharMountain, 75 km NW of Tehran, consists of about 1000 m of siliciclastic rocks (mainly mudrocks). This study focuses on the mineralogical and geochemical composition of these mudrocks to identify possible source areas and their tectonic setting. The optical microscopy and XRD studies suggest that the mudrocks are rich in quartz and feldspar (especially plagioclase) and have low phyllosilicates (mostly illite and chlorite). SEM-EDX petrographic investigation of mudrocks reveals that platy illite and chlorite may have formed during the diagenesis (illitization and chloritization). Classification of studied mudrocks based on the maturity index, indicate that they are tectic and phyllo-tectic types, deposited in basins related to an (continental) island arc tectonic setting. The Chemical Index of Alteration (average 70) and A–CN–K parameters indicate that a moderate chemical weathering has taken place in the source region of the Kahar mudrocks. In addition, the chemical composition of mudrocks suggests that the amount of sediment recycling is very low in the Kahar deposits. The geochemical discrimination diagrams, immobile trace element ratios and Rare Earth Elements of mudrocks suggest that the Kahar mudrocks were derived mainly from the felsic sources and deposited in the basins related to an island arc tectonic setting. The resulting model for the tectonic setting of the Kahar basin during the Late Neoproterozoic can be best explained by recently models that considered Iran as part of Peri-Gondwanan terranes, similar to the Avalonia and Cadomia arc terranes, occupying the northern margins of Gondwana. The Kahar Formation at its type locality in the KaharMountain, 75 km NW of Tehran, consists of about 1000 m of siliciclastic rocks (mainly mudrocks). This study focuses on the mineralogical and geochemical composition of these mudrocks to identify possible source areas and their tectonic setting. The optical microscopy and XRD studies suggest that the mudrocks are rich in quartz and feldspar (especially plagioclase) and have low phyllosilicates (mostly illite and chlorite). SEM-EDX petrographic investigation of mudrocks reveals that platy illite and chlorite may have formed during the diagenesis (illitization and chloritization). Classification of studied mudrocks based on the maturity index, indicate that they are tectic and phyllo-tectic types, deposited in basins related to an (continental) island arc tectonic setting. The Chemical Index of Alteration (average 70) and A–CN–K parameters indicate that a moderate chemical weathering has taken place in the source region of the Kahar mudrocks. In addition, the chemical composition of mudrocks suggests that the amount of sediment recycling is very low in the Kahar deposits. The geochemical discrimination diagrams, immobile trace element ratios and Rare Earth Elements of mudrocks suggest that the Kahar mudrocks were derived mainly from the felsic sources and deposited in the basins related to an island arc tectonic setting. The resulting model for the tectonic setting of the Kahar basin during the Late Neoproterozoic can be best explained by recently models that considered Iran as part of Peri-Gondwanan terranes, similar to the Avalonia and Cadomia arc terranes, occupying the northern margins of Gondwana. http://www.gsjournal.ir/article_42729_0993516af65b808834c16f3415c05000.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Geochemical Characteristics of the Sarvak Formation in Izeh Zone, Zagros RegionGeochemical Characteristics of the Sarvak Formation in Izeh Zone, Zagros Region2993104273010.22071/gsj.2015.42730FAE Asadi MehmandostiAssistant Professor, Department of Geology, Faculty of Earth Sciences, Kharazmi University, Tehran, IranM.H AdabiProfessor, Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, IranJournal Article20120821The Sarvak Formation from the Bangestan Group, Late Albian to Cenomanian in age is an important petroleum reservoir in Iran. 5 outcrop sections in the Izeh zone, including the BangestanMountain as a type section with 831.5 m thickness, the MangashtMountain with 426 m thickness, the PayunMountain with 480 m thickness, the north flank of MishMountain with 252 m thickness and the south flank of MishMountain with 348 m thickness were studied geochemically. The major elements (Ca, Mg), trace elements (Sr, Na, Fe, Mn) and carbon and oxygen isotopes studies indicate that the geochemical characteristics of the Sarvak Formation have been changed in the Izeh zone. High amount of Sr/Mn ratio and Sr content normalized to Ca and heaviest oxygen isotope of the Sarvak Formation carbonates in the north flank of Mish Mountain and some of the Bangestan Mountain carbonate samples indicate low amount of solution and closed diagenetic system in these outcrops compare to the Sarvak Formation carbonates in the south flank of Mish and Payun Mountains. The oxygen and carbon isotopes variation illustrate marine pheriatic digenesis in the north flank of Mish and BangestanMountains and meteoric diagenesis in the south flank of Mish, Mangasht and PayunMountains. The geochemical difference, which observed in the studied sections at Izeh zone, could be related to the reactivation of deep seated structures such as the Hendijan and Bahregansar (Izeh) faults, which caused thickness, facies and diagenetic variations in these areas.The Sarvak Formation from the Bangestan Group, Late Albian to Cenomanian in age is an important petroleum reservoir in Iran. 5 outcrop sections in the Izeh zone, including the BangestanMountain as a type section with 831.5 m thickness, the MangashtMountain with 426 m thickness, the PayunMountain with 480 m thickness, the north flank of MishMountain with 252 m thickness and the south flank of MishMountain with 348 m thickness were studied geochemically. The major elements (Ca, Mg), trace elements (Sr, Na, Fe, Mn) and carbon and oxygen isotopes studies indicate that the geochemical characteristics of the Sarvak Formation have been changed in the Izeh zone. High amount of Sr/Mn ratio and Sr content normalized to Ca and heaviest oxygen isotope of the Sarvak Formation carbonates in the north flank of Mish Mountain and some of the Bangestan Mountain carbonate samples indicate low amount of solution and closed diagenetic system in these outcrops compare to the Sarvak Formation carbonates in the south flank of Mish and Payun Mountains. The oxygen and carbon isotopes variation illustrate marine pheriatic digenesis in the north flank of Mish and BangestanMountains and meteoric diagenesis in the south flank of Mish, Mangasht and PayunMountains. The geochemical difference, which observed in the studied sections at Izeh zone, could be related to the reactivation of deep seated structures such as the Hendijan and Bahregansar (Izeh) faults, which caused thickness, facies and diagenetic variations in these areas.http://www.gsjournal.ir/article_42730_3626a5962e30afd901a6e826d7b299b2.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Petrophysical Analysis and Prediction of Porosity Function in One of the Southwest Reservoirs of IranPetrophysical Analysis and Prediction of Porosity Function in One of the Southwest Reservoirs of Iran3113164273110.22071/gsj.2015.42731FAA Abbaszadeh ShahriAssistant Professor, Department of Civil Engineering, Islamic Azad University, Rudehen Branch, Tehran, IranR HosseiniM. Sc., Department of Geology, Islamic Azad University, Damavand Branch, Damavand, IranF RezaeiAssistant Professor, Research Institiute for Earth Sciences, Geological Survey of Iran, Tehran, IranK MehdizadehM. Sc., Department of Geology, Islamic Azad University, Damavand Branch, Damavand, IranN PanaeiM. Sc., Department of Geology, Islamic Azad University, Damavand Branch, Damavand, IranJournal Article20120904Artificial Neural Network methods (ANN) are computational methods, which capable to predict a specific log or classify different data. Unlike the digital computers, which require the completely definite and distinguished rules, the ANN methods do not need a pure mathematical model; rather like the human brain has the ability to learn by recognized and determined examples. The target of the present paper is to establish and prove the Petrophysical Analysis as powerful approach in prediction and diagnosis of rock reservoir porosity by use of petrophysical logs, in which by a high accuracy suggested Petrophysical Analysis based solution the porosity can be estimated using conventional logging data. On the basis of the available petrophysical data, the proposed method was examined in one of the southwest oil field of Iran. The obtained results of network analysis conditioning to reliability to data with different tests such as regression, root mean square and SPLine showed that the amount of network error in terms of available data in engineering range with a high acceptable safety factor could be used to predict and estimate porosity. This method with ability of cost reduction and viability can help and provide a large variety in this field for further extended research.Artificial Neural Network methods (ANN) are computational methods, which capable to predict a specific log or classify different data. Unlike the digital computers, which require the completely definite and distinguished rules, the ANN methods do not need a pure mathematical model; rather like the human brain has the ability to learn by recognized and determined examples. The target of the present paper is to establish and prove the Petrophysical Analysis as powerful approach in prediction and diagnosis of rock reservoir porosity by use of petrophysical logs, in which by a high accuracy suggested Petrophysical Analysis based solution the porosity can be estimated using conventional logging data. On the basis of the available petrophysical data, the proposed method was examined in one of the southwest oil field of Iran. The obtained results of network analysis conditioning to reliability to data with different tests such as regression, root mean square and SPLine showed that the amount of network error in terms of available data in engineering range with a high acceptable safety factor could be used to predict and estimate porosity. This method with ability of cost reduction and viability can help and provide a large variety in this field for further extended research.http://www.gsjournal.ir/article_42731_05060dbf205243b2da86de2ac36b5cd8.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Geochemical Evaluation of Organic Matter of the Pabdeh and Gurpi Formations in Nosrat Oil Field, SE Persian Gulf, Using Rock-Eval VI and Gas ChromatographyGeochemical Evaluation of Organic Matter of the Pabdeh and Gurpi Formations in Nosrat Oil Field, SE Persian Gulf, Using Rock-Eval VI and Gas Chromatography3173264273210.22071/gsj.2015.42732FAM SadeghiM.Sc., School of Mining, Petroleum and Geophysics Engineering, Shahrood University of Technology, Shahrood, IranM.R KamaliAssociate Professor, Research Institute of Petroleum Industry, Tehran, IranR Ghavami RiabiAssistant Professor, School of Mining, Petroleum and Geophysics Engineering, Shahrood University of Technology, Shahrood, IranB QorbaniM.Sc., Research Institute of Petroleum Industry, Tehran, IranJournal Article20130721In this study, rock samples from the pabdeh and Gurpi formations of well#NH-01 in the Nosrat Oil Field subjected to geochemical evaluation techniques using Rock-Eval pyrolysis, bitumen extraction, Column Chromatography and gas chromatography. The result of geochemical study indicates Kerogen type II and III. However, most samples tend to related kerogen Type II suggesting that source rock was deposited in the anoxic to suboxic environments and most organic matter derived from marine and partly from terrestrial sources. The pabdeh Formation shows fair to good hydrocarbon potential and has already entered oil generation window, whereas the Gurpi Formation has Poor to fair hydrocarbon potential. The Gas chromatography conducted on these samples indicates that most samples are rich in saturated hydrocarbons and also suggests organic matter of the pabdeh and Gurpi formations are all indigenous. In this study, rock samples from the pabdeh and Gurpi formations of well#NH-01 in the Nosrat Oil Field subjected to geochemical evaluation techniques using Rock-Eval pyrolysis, bitumen extraction, Column Chromatography and gas chromatography. The result of geochemical study indicates Kerogen type II and III. However, most samples tend to related kerogen Type II suggesting that source rock was deposited in the anoxic to suboxic environments and most organic matter derived from marine and partly from terrestrial sources. The pabdeh Formation shows fair to good hydrocarbon potential and has already entered oil generation window, whereas the Gurpi Formation has Poor to fair hydrocarbon potential. The Gas chromatography conducted on these samples indicates that most samples are rich in saturated hydrocarbons and also suggests organic matter of the pabdeh and Gurpi formations are all indigenous. http://www.gsjournal.ir/article_42732_15bb2e1fbf02280c4185dd4d0ace8292.pdfGeological Survey of IranScientific Quarterly Journal of Geosciences1023-7429249420150220Geochemistry of the Upper Sarvak (Mishrif Member) Formation and the Diagenetic Processes Effects on the Reservoir Quality of this Member,
Sirri E and D Oil FieldsGeochemistry of the Upper Sarvak (Mishrif Member) Formation and the Diagenetic Processes Effects on the Reservoir Quality of this Member,
Sirri E and D Oil Fields3272384273310.22071/gsj.2015.42733FAA GhorbaniM. Sc., Department of Geology, Faculty of Earth Science, Shahid Beheshti University, Tehran, IranM.H AdabiProfessor, Department of Geology, Faculty of Earth Science, Shahid Beheshti University, Tehran, IranS SohrabiM. Sc., Iranian Offshre Oil Company, Tehran, IranJournal Article20110718The Sirri E (Esfand) and D (Dena) Oil Fields are located in the south of the Persian Gulf. The Upper Sarvak (Mishrif Member) Formation, late Cretaceous (Cenomanian-Turonian) in age, is underlain by the argillaceous limestone of Khatiyah and by the late Turonian unconformity overlain by the Laffan Shale in mentioned two oil fields. On the basis of petrographic and geochemical evidences (elemental analysis such as Mg, Ca, Sr, Mn) and oxygen and carbon isotope values, aragonite was original carbonate mineralogy for the carbonates of the Upper Sarvak (Mishrif Member) Formation in (Well A) in the Sirri E Field. The geochemical studies and δ<sup>18</sup>O and δ<sup>13</sup>C illustrate that these carbonates were affected by meteoric diagenesis in hot and arid climate and in semi-closed to open diagenetic system with thin soil layer. Temperature calculation based on the oxygen isotope value of the least-altered sample and δ<sub>w</sub> around of -1 SMOW for Cretaceous, show that the seawater temperature was around 34˚C during the deposition of the Upper Sarvak (Mishrif Member) Formation. With regards to the highly altered samples and light oxygen values the temperature should be probably related to the shallow burial diagenesis. Petrographic studies of thin sections of the well A in the Sirri E Field and the well B in the Sirri D Field show the effect of diagenetic processes such as micritization, dissolution, cementation, neomorphism, pressure solution, physical compaction, fracture and dolomitization on the reservoir quality of the Upper Sarvak (Mishrif Member) Formation. The most important diagenetic factor that increased the reservoir quality is dissolution, which occurred in the meteoric diagenesis. However, the most important diagenetic factor that decreased the reservoir quality is the expansion of various kinds of cement especially large blocky cement, which occurred in the burial diagenesis.The Sirri E (Esfand) and D (Dena) Oil Fields are located in the south of the Persian Gulf. The Upper Sarvak (Mishrif Member) Formation, late Cretaceous (Cenomanian-Turonian) in age, is underlain by the argillaceous limestone of Khatiyah and by the late Turonian unconformity overlain by the Laffan Shale in mentioned two oil fields. On the basis of petrographic and geochemical evidences (elemental analysis such as Mg, Ca, Sr, Mn) and oxygen and carbon isotope values, aragonite was original carbonate mineralogy for the carbonates of the Upper Sarvak (Mishrif Member) Formation in (Well A) in the Sirri E Field. The geochemical studies and δ<sup>18</sup>O and δ<sup>13</sup>C illustrate that these carbonates were affected by meteoric diagenesis in hot and arid climate and in semi-closed to open diagenetic system with thin soil layer. Temperature calculation based on the oxygen isotope value of the least-altered sample and δ<sub>w</sub> around of -1 SMOW for Cretaceous, show that the seawater temperature was around 34˚C during the deposition of the Upper Sarvak (Mishrif Member) Formation. With regards to the highly altered samples and light oxygen values the temperature should be probably related to the shallow burial diagenesis. Petrographic studies of thin sections of the well A in the Sirri E Field and the well B in the Sirri D Field show the effect of diagenetic processes such as micritization, dissolution, cementation, neomorphism, pressure solution, physical compaction, fracture and dolomitization on the reservoir quality of the Upper Sarvak (Mishrif Member) Formation. The most important diagenetic factor that increased the reservoir quality is dissolution, which occurred in the meteoric diagenesis. However, the most important diagenetic factor that decreased the reservoir quality is the expansion of various kinds of cement especially large blocky cement, which occurred in the burial diagenesis.http://www.gsjournal.ir/article_42733_2f4cd1bf9ca05d7774d2a2ccd17bb1d4.pdf