-
دسترسی آزاد مقاله
1 - The study of post depositional history in the Chehel Kaman formation, in the eastern regions of Kopet-Dagh, North-East Iran
Somayeh Erfani Mohammad Javanbakht Mehdireza PoursoltaniThe Chehel Kaman Formation of the upper Paleocene age formed from carbonate and siliciclastic sediments is located, in the Kapeh Dagh Sedimentary Basin. Two sections where considered for the purpose of research into the effective diagenetic processes of this formation. چکیده کاملThe Chehel Kaman Formation of the upper Paleocene age formed from carbonate and siliciclastic sediments is located, in the Kapeh Dagh Sedimentary Basin. Two sections where considered for the purpose of research into the effective diagenetic processes of this formation. The Cheshmeh Qorban section with a thickness of 270.8m located 140km down the Mashhad – Sarakhs Highway while the Shourlog Section with a thickness of 288.3m is situated 130km down the Mashhad – Mozduran – Sarakhs Highway. 120 samples were taken from these sections and 100 thin cross sections produced from these samples. The carbonate rocks of this formation have been affected by diagenetic processes such as cementation, micritization, neomorphism, dissolution stress and porosity. These processes have taken place at the four marine diagenetic stages of the underground and surface sweet water. All cross sections were investigated using a gypsum bladein order to identify any extant porosity. All changes including type and percentage were plotted for each section. The results of the investigations indicated that in the Cheshmeh Qorban section of the Chehel Kaman Formation the lowest porosity content with a 3% rate of recurrence was related to microporosities while the greatest accumulation of porosity with a 7% recurrence rate in porosity was due to fracture porosity. In the Shourlog section meanwhile the lowest porosity content with a 2% recurrence rate was related to microporosities and the greatest accumulation with a recurrence rate of 6% was due to vuggy porosity. پرونده مقاله -
دسترسی آزاد مقاله
2 - Lithostratigraphy ,biostratigraphy of Paleocene-lower Eocene squences in Dezful embeyment, South West Iran
Fatemeh Moradian Darioush BaghbaniPaleocene and Lower Eocene deposits in SW Iran are known as Pabdeh formation.Pabdeh formation is one of the most important lithostratigraphy unit as source rock has been deposited in Zagros basin over an extremely long period in time. The area under research is the Ghac چکیده کاملPaleocene and Lower Eocene deposits in SW Iran are known as Pabdeh formation.Pabdeh formation is one of the most important lithostratigraphy unit as source rock has been deposited in Zagros basin over an extremely long period in time. The area under research is the Ghachsaran 55 subsurface Section located from the Ghachsaran oil field in Dezful embeyment in zagros fold zone. The Lower boundry of this formation around Ghachsaran basin is identified by Gurpi formation. Study on lithostratigraphy of Paleocene and lower Eocene deposits have been led to the separation following units: clay limestone section in gray colour,11m in thickness, clay limestone section 18m in thickness containing chert inter layers, silt clay limestone section 3m in thickness, The clay limestone section 3m in thickness containing chert interlayers, clay limestone section 4m in thickness . biostratigraphy investigation of Pabdeh formation have been led to the identification of 39 species and 9 genera of foraminifers.In addition , basis of Paleocene- Early Eocene planktonicforamimnifers bioevent in Wade biozonation such as Morozovella velascoensis, Globanomalina pseudomenardii, Psudohastigerina wilcoxensis, Acarinina soldadoensis , Morozovella subbotinae , Morozovella formosa , 9 biozones and 4 subzones are recogenized and these correlated with oldest biozones of (Wynd 1965) Beside,the bio-boundary of Paleocene and early Eocene is identified based on (Wade et al. 2011). پرونده مقاله -
دسترسی آزاد مقاله
3 - Mineral chemistry and thermobarometry of Eocene alkaline volcanic rocks in SW Germi, NW Iran
Mohammad Mobashergermi Reza Zarei Sahamieh Mehraj Aghazadeh Ahmad Ahmadikhalaj Gholamreza AhmadzadehPetrography and chemistry of minerals showing that Eocene alkaline volcanic rocks in southwestern of Germi (Talesh zone, NW Iran) mostly have basaltic composition. Mineralogically these rocks are composed of diopsidic clinopyroxene and labradoritic plagioclase phenocrys چکیده کاملPetrography and chemistry of minerals showing that Eocene alkaline volcanic rocks in southwestern of Germi (Talesh zone, NW Iran) mostly have basaltic composition. Mineralogically these rocks are composed of diopsidic clinopyroxene and labradoritic plagioclase phenocrysts. The microlithic and glassy groundmass composed of sanidine, clinopyroxene, biotite, pargasitic amphibole and magnetite associated with devitrified glass. Clinopyroxenes show relatively high Mg-numbers (0.76-0.93), low AlVI (mostly <0.1), suggesting relatively low-pressure (~5), and water content ~2.5 to less than 10% and high oxygen fugacity (-8.38-11.51) of crystallization condition. High amount existence of magnetite coexisting with amphibole and biotite mineral confirm high fugacity of the host magma. According to clinopyroxene and feldspar thermometry, estimated crystallization temperature varies between 1106˚C to ~1200 ˚C. The clinopyroxene and amphibole mineral composition of studied rocks indicate that they have been formed in a back-arc basin environment. Mineral chemistry in the current zone shows that composition and genesis of common minerals these magmatic rocks are similar to Pushtasar basaltic rocks in the northern part of this area. پرونده مقاله -
دسترسی آزاد مقاله
4 - Biostratigraphy, microfacies and sedimentary environment of the Jahrum Formation in Chaharmahal Bakhtiari province, West of Iran
Bahman Javadian Seyed Ahmad Babazadeh Ali Solgi Burzu Asghari PirbalutiIn this research, the biostratigraphy, microfacies, and depositional environment of carbonate sediments of the Jahrum Formation will be investigated based on microscopic textures and the distribution of benthic foraminifera. The Jahrum Formation was measured from Kuh-e- چکیده کاملIn this research, the biostratigraphy, microfacies, and depositional environment of carbonate sediments of the Jahrum Formation will be investigated based on microscopic textures and the distribution of benthic foraminifera. The Jahrum Formation was measured from Kuh-e-Hamze Ali in the Chaharmahal Bakhtiari province (Zagros Basin, Iran). The biostratigraphic analysis of this formation has led to the detection of three biozones in this area. These biozones consist of Somalina subzone, Nummulites–Alveolina assemblage subzone, and Nummulites fabianii- Nummulites striatus assemblage subzone which assigned to Middle and Late Eocene. The Nummulites fabianii- Nummulites striatus assemblage subzone is represented for the first time in the studied area. Nine microfacies are identified based on their fossil content (mainly foraminifera) and sedimentary textures. They consist of Dolostone, Mudstone with quartz, Bioclast- miliolids wackestone/packstone, Praerhapydionina -miliolid wackestone, Alveolina -Nummulites-Orbitolites wackestone/packstone, Bioclast–miliolid-Rotalia wackestone/packstone, Bioclast-lump packstone/grainstone, Interaclast-bioclast-Alveolina wackestone/grainstone, and Bioclast-Nummulites wackestone/packstone. These facies were deposited in four major depositional environments from a tidal flat, lagoon, shoal, and open marine environmental settings. The depositional environment of the Jahrum Formation is interpreted as a carbonate ramp. پرونده مقاله -
دسترسی آزاد مقاله
5 - Petrology and tectono-magmatic environment of the volcanic rocks of West Torud – Iran
Abdollah Yazdi Elham Shahhosseini Farhad MoharamiMiddle-Upper Eocene volcanic and volcano-sedimentary rocks of the Torud region have been formed by the sequences of basic-intermediate lavas, pyroclastic rocks, and sedimentary layers (e.g., siltstone, sandstone, and nummulite-bearing limestone) within a shallow marine چکیده کاملMiddle-Upper Eocene volcanic and volcano-sedimentary rocks of the Torud region have been formed by the sequences of basic-intermediate lavas, pyroclastic rocks, and sedimentary layers (e.g., siltstone, sandstone, and nummulite-bearing limestone) within a shallow marine basin. According to microscopic studies, the volcanic rocks of the region include basalt, basaltic andesite, trachyandesite, andesite, and dacite. These rocks have originated from the differential crystallization processes and occasionally calc-alkaline contamination geochemical properties. Generally, they contain olivine, clinopyroxene, and plagioclase ± amphibole minerals. Porphyritic to megaporphyritic textures with microlithic and flow matrixes are observed in these rocks. Studying the main and rare elements of these rocks indicates that reducing MgO content is accompanied by an increase in Al2O3, K2O, Na2O, and SiO2 and a decrease in Fe2O3 and CaO concentrations. These rocks are mainly enriched in LIL and LREE elements but depleted of HFS elements. The prominent features of these rocks are the presence of positive anomalies in the K, Sr, Rb, and Ba elements, the depletion of some samples of Nb and Ta, and their depletion of Ti and P. This result reveals the crustal contamination of the mantle mafic magma constructing these rocks. According to the geochemical data, magmatic pollution has not been an effective process in the formation of these rocks. In addition, the relatively higher levels of Cr, Ni, and MgO in the alkali basalts of the region indicate that these rocks are originated from partial melting (5 to 10%) of a spinel-garnet peridotite. Overall, they have no subduction-dependent rock characteristics and mainly represent characteristics of alkali basaltic magmas of the preliminary back-arc basin (BAB). These features, attributed to their calc-alkaline nature, represent the formation of these rocks in a tectonic back-arc setting in the Middle-Upper Eocene. پرونده مقاله -
دسترسی آزاد مقاله
6 - First report of the SardinellaSardinites (Heckel, 1850) in the Kond formation in the Saran area, Central Alborz in Iran
Saeedeh Senemari Leila Fazli Alireza CheginiInvestigating the fossil-bearing horizons of the Kond Formation in the Saran area resulted in the identification of Sardinellasardinites (Heckel 1850) belonging to the family of Clupeidae Bonaparte (1831) for the first time the east of Tehran province. Furthermore, bios چکیده کاملInvestigating the fossil-bearing horizons of the Kond Formation in the Saran area resulted in the identification of Sardinellasardinites (Heckel 1850) belonging to the family of Clupeidae Bonaparte (1831) for the first time the east of Tehran province. Furthermore, biostratigraphic analyses based on the presence of benthic and planktonic foraminifera in this area demonstrate that the sedimentary sequence including strata of conglomerate, tuff, shale, gypsum, limestone, and marl with a thickness of 376 m in the Saran area belongs to the Priabonian, which is discontinuously located on Middle Eocene green tuffaceousshales. In the present study, 18 species belonging to 9 genera from the benthic foraminifera were identified. In the late Middle Eocene, the performance of the orogenic Pyrenean phase led to the rising of the sedimentary strata and subsequent retreat of the sea and then the sea re-advanced during the Priabonian stage. The presence of a conglomerate at the base of the formation reveals the next activity of the tectonic phase. In this study, the rock unit of the Lower Red Formation belonging to the Oligo-Miocene is located on the deposits of the Kond Formation. پرونده مقاله -
دسترسی آزاد مقاله
7 - Petrogenesis of volcanic rocks from Razei region in Northwest Ardabil, Iran
Yousef VasighThe Razei region in the northwest of Ardabil is considered a part of West Alborz-Azerbaijan. Rocks in this area were created by Eocene volcanic activities. These rocks range from andesite to olivine basalt. The common texture of these rocks is Porphyritic with microlith چکیده کاملThe Razei region in the northwest of Ardabil is considered a part of West Alborz-Azerbaijan. Rocks in this area were created by Eocene volcanic activities. These rocks range from andesite to olivine basalt. The common texture of these rocks is Porphyritic with microlithic matrix. The phenocrysts of these rocks are often clinopyroxene, plagioclase, and olivine. The texture is made of microlithic plagioclase and fine crystals of pyroxene. The studied rocks have clear desire to alkali basalts in terms of chemical nomenclature. Disequilibrium factors between liquid and crystal show the processes of magmatic evolution in an open thermodynamic system. The mixed climate in this region has probably contributed the most to changing the chemical composition of these rocks. In the spider diagrams, enrichments often include some LIL elements and depletions usually include some HFS elements. Enrichment of LILE is probably accompanied with the contamination of the basic magma with materials from continental lithosphere. The volcanic rocks in Razei have mainly geochemical characteristics of back arc basin, and the magmas that created the rocks in this region have an origin of lithospheric mantle. پرونده مقاله -
دسترسی آزاد مقاله
8 - Microbiostratigraphy of Middle Eocene ShahbazanFormation at the southeastern flank of Chenar Anticline,Lurestan Basin, Sw Iran
I. Maghfouri Moghadam M. Taherpour Khalil AbadIn this research, biostratigraphy related to the carbonate succession of the Shahbazan Formation at the southeastern flank of Chenar anticline, Lurestan Basin, is discussed. A study of large benthic foraminifera from the 294 mthick Shahbazan Formation led to the identif چکیده کاملIn this research, biostratigraphy related to the carbonate succession of the Shahbazan Formation at the southeastern flank of Chenar anticline, Lurestan Basin, is discussed. A study of large benthic foraminifera from the 294 mthick Shahbazan Formation led to the identification of two Middle Eocene biozones: Somalina sp. Zone, Nummulites-Alveolina Assemblage Zone. The age of the Shahbazan Formation in the study area is determined as Middle Eocene. The Shahbazn Formation overlies the Pabdeh Formation and underlies Asmari Formation in the studied stratigraphic section. The lower part of Asmari Formation is characterized by thick – bedded of limestone, with Nerpherolepidina sp., which reflects deposition during Chattian age. In this study, we introduced a paraconformity between Shabazan and Asmari Formations which is attributed to the PriabonianChattian. پرونده مقاله -
دسترسی آزاد مقاله
9 - بررسی پالئواکولوژی و شرایط اقیانوسی دیرینه سازند خانگیران بر اساس عدم حضور ، ) Morozovellaفرامینیفر شاخص ائوسن
میر امیر صلاحی محمد وحیدی نیاحوضه رسوبی کپه داغ در شمال و شمال شرقی ایران قرار گرفته و سازند خانگیران یکی از مهمترین سازندهای متعلق به دورهپالئوژن این حوضه می باشد. برای مطالعه این سازند برش ناودیس چهل کمان واقع در جنوب غرب شهر سرخس، شرق حوضهرسوبی کپه داغ انتخاب گردید. این برش به ضخامت 136متر و لیت چکیده کاملحوضه رسوبی کپه داغ در شمال و شمال شرقی ایران قرار گرفته و سازند خانگیران یکی از مهمترین سازندهای متعلق به دورهپالئوژن این حوضه می باشد. برای مطالعه این سازند برش ناودیس چهل کمان واقع در جنوب غرب شهر سرخس، شرق حوضهرسوبی کپه داغ انتخاب گردید. این برش به ضخامت 136متر و لیتولوژی آن شامل تناوبی از مارن به رنگ سبز زیتونی و مارنآهکی به رنگ زرد کرمی می باشد. در این تحقیق فونای فرامینیفری سازند خانگیران مورد مطالعه قرار گرفت. این برش به سنائوسن پیشین - میانی از نظر فونای فرامینیفرهای پلانکتونیک نشان دهنده ناهنجاری هایی می باشد که بر این اساس عدم حضور، Morozovellaبه عنوان جنس شاخص ائوسن را می توان ذکر کرد. این امر با توجه به مطالعه فونای فرامینیفرهای پلانکتونیکو بنتونیک این سازند ناشی از شرایط یوتروفیک می باشد. این شرایط در نتیجه تغییرات رخ داده در شرایط اقیانوسی دیرینه، نظیروضعیت لایه بندی ستون آب و تغییرات مواد مغذی حاصل شده است. با توجه به اینکه Morozovellidها قادر نیستند خود را باشرایط یوتروفیک وفق دهند باعث عدم حضور گونه های این جنس در سازند خانگیران شده است. شرایط حاکم بر سازند خانگیرانقابل مقایسه با شرایط حاکم بر حوضه های واقع در منطقه قفقاز بوده و این امر می تواند نشان دهنده شرایط یکسان حوضه هایکپه داغ و منطقه قفقاز حداقل در طول ائوسن باشد پرونده مقاله -
دسترسی آزاد مقاله
10 - Biostratigraphy of the sediments of Talezang Formation in southwestern Lorestan
Mehdi SafdariThe Talezang Formation is especially extensively outcropped in southwestern Lorestan. It is lying conformably on the Amiran Clastic Formation and its upper boundary contacts the Kashkan Red Siltstone Formation. In the type section it is dated at Upper Paleocene to Middl چکیده کاملThe Talezang Formation is especially extensively outcropped in southwestern Lorestan. It is lying conformably on the Amiran Clastic Formation and its upper boundary contacts the Kashkan Red Siltstone Formation. In the type section it is dated at Upper Paleocene to Middle Eocene and is composed of limestone ranging from moderate beddings to massive form. Limestones of the selected sections are mostly sandy with sandstone and shale interbeds. Miscellanea Miscella, Miscellanea Minauta, Kathina sp., Lockhartia sp., Gavelinella sp. are the typical fossils which are defined in the selected sections of this Formation. The proposed age for the formation is dated at the Upper Paleocene – Iberian. پرونده مقاله -
دسترسی آزاد مقاله
11 - Microbiostratigraphy of the Taleh-Zang Formation, Lorestan Basin
Iraj Maghfouri MoghadamThe Taleh-Zang Formation is a predominantly carbonate lithostratigraphic unit that crops out in Lorestan sedimentary basin, southwestern Iran . Lorestan sedimentary basin, formed as a foreland basin in Central Zagros, is characterized by a relatively continuous Cretaceo چکیده کاملThe Taleh-Zang Formation is a predominantly carbonate lithostratigraphic unit that crops out in Lorestan sedimentary basin, southwestern Iran . Lorestan sedimentary basin, formed as a foreland basin in Central Zagros, is characterized by a relatively continuous Cretaceous to Miocene time. In this paper, the microbiostratigraphy of the Taleh- Zang Formation in seven measured stratigraphic sections (Taleh- Zang type section, Kialou, Veisian, Chenar, Ghalebi, Darabi and Chahr Zebr) are is discussed. In all sections, the lower and upper boundaries of the Taleh- Zang Formation with Amiran and Kashkan Formations are conformable. Microbiostratigraphic data mainly based on foraminifera indicate the Middle Paleocene to Late Paleocene for the Taleh- Zang Formation for Veisian and the Early to Late Paleocene at Ghalebi, Darabi and Chenar, the Middle Paleocene for For Chahr Z¹ebr, the Late Paleocene to the Middle Eocence at the type section and the Late Paleocene to Early Eocene at the Kialou section. پرونده مقاله
سکوی نشر دانش
سند یا سکوی نشر دانش ،سامانه ای جهت مدیریت حوزه علمی و پژوهشی نشریات دانشگاه آزاد می باشد
پیوندهای سایت
مراکز مرتبط
پشتیبانی
صفحات رسمی
حقوق این وبسایت متعلق به سامانه مدیریت نشریات دانشگاه آزاد اسلامی است.
حق نشر © 1403-1400