Stratigraphy and Palaeontology
shahram navavajary; Iraj Maghfouri Moghaddam; Ali Reza Shahidi; Hamid Nazari
Abstract
Oligo-Miocene rocks are deposited between Pyrenean and Pasadenian orogenic phases. This rocks in central Iran back arc deposits are named Qom formation. There are well developed outcrops of Qom formation at the North of Central Iran zone. In order to study microbiostratigraphy of the formation, Three ...
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Oligo-Miocene rocks are deposited between Pyrenean and Pasadenian orogenic phases. This rocks in central Iran back arc deposits are named Qom formation. There are well developed outcrops of Qom formation at the North of Central Iran zone. In order to study microbiostratigraphy of the formation, Three sections, north west of Darjazin town , Bonak mount and Arvaneh were selected. In these sections Qom formation with discontinuity overlays the Lower Red formation and with the same quality under the Late Miocene Conglomerate with intercalations of Sandstone, which is equivalent to the Upper Red Formation is placed. The main lithological composition of the Qom Formation in the study area alternates between layers of limestone and Marl with intercalations of siliciclastic rocks. Members and submembers of the Qom formation type area are not visible in this area and can only based on the lithological characteristics divide to local units. Based on bentic foraminifera and other microbiostratigraphical data, Qom Formation age in north west-west of Semnan (Darjazin-After zone), which is located in the Central Alborz structural- sedimentary zone, is early Miocene epoch and Burdigalian stage, which is the equivalent of Borelis melo curdica-Borelis melo biozone.
Sedimentology
Umid Kakemem; Mohammad Adabi; Bahman Gudarzi
Abstract
Investigating of dolomitization and its effects on reservoir quality of the Upper Dalan Formation with Permian-Triassic in age is the aim of this study. In this section, the Upper Dalan Formation consists of carbonates and evaporite rocks with a thickness of 265m. Eleven carbonate- evaporate microfacies ...
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Investigating of dolomitization and its effects on reservoir quality of the Upper Dalan Formation with Permian-Triassic in age is the aim of this study. In this section, the Upper Dalan Formation consists of carbonates and evaporite rocks with a thickness of 265m. Eleven carbonate- evaporate microfacies have been distinguished on the basis of depositional textures, petrographic analysis and present fauna. These microfacies were deposited in three facies belts including tidal flat, lagoon and carbonate shoal. Absents of turbidite (calciturbidite) and tempesties deposits, slump structures, large barrier reef, widespread tidal flat and lagoonal facies with aboundent of mud matrix indicated that depositional setting of this interval was a homoclinal carbonate ramp. Based on petrographic studies, 4 types of dolomite including dolomicrite, dolomicrosparite, dolosparite and dolomite cement are recognized. Porosity and permeability data in varies dolomites reveals that in most dolomite the amount of permeability is not directly related to whole porosity, but depends mainly on the amount of connected porosities through bottleneck holes and is associated with increasing in dolomite crystal sizes. Therefore, from the early stage of dolomitization in the form of dolomicrite toward increasing in the rate of dolomitization with larger crystal size and with the form of subhedral and euhedral crystals, the reservoir properties had a high visible improvement. Ultimately, by persisting of dolomitization and growth of dolomite crystals toward each other and disappearance of bottleneck holes and creation of dolomite cements, reservoir properties destroyed. Dolomitization increased reservoir quality in grain dominated dolo-packstones with planner crystal texture.
Petroleum geology
Bita Arbab; Davood Jahani; Bahram Movahed
Abstract
The Aptian Shuaiba deposits, in southeastern of Persian Gulf due to having resistivity less than 6 to 1 ohm.m, is considered as low resistivity pay zone. On the basis of experimental studies 8 microfacies defined which settled in a carbonate platform of homoclinal ramp model that belong to outer, ...
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The Aptian Shuaiba deposits, in southeastern of Persian Gulf due to having resistivity less than 6 to 1 ohm.m, is considered as low resistivity pay zone. On the basis of experimental studies 8 microfacies defined which settled in a carbonate platform of homoclinal ramp model that belong to outer, middle, inner ramp. Existence micro porosity in the microfacies is main reason for lowering resistivity. Various digenetic process are seen such as micritization and pyritization which have noticeable impact on declining resistivity. Lønøy method applied to address pore throat sizes which contain Intercrystalline porosity, Chalky limestone, Mudstone micro porosity. Pore systems are at class 3 Lucia. NMR logs and core data have been used for defining reliable water saturation and reservoir characterization. Results explain that decreasing of resistivity in pay zone is related to texture and grain size variation not being existence of moved water .Irreducible water estimate for this reservoir between 30 to 50 %.
M. Soltani Najafabadi; S. A. Babazadeh; M. Aleali; B. Asgari Pirbaluti
Abstract
Jahrom Formation is dominated by gray thick bedded limestones that mainly consist foraminifera. Two stratigraphic sections, (Saldoran and Dasht-Zari) were selected for this research and the thickness of this formation is reached to 176.5 and 200 m respectively. These sections are located in west of Shahr-e- ...
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Jahrom Formation is dominated by gray thick bedded limestones that mainly consist foraminifera. Two stratigraphic sections, (Saldoran and Dasht-Zari) were selected for this research and the thickness of this formation is reached to 176.5 and 200 m respectively. These sections are located in west of Shahr-e- Kord,(High Zagros). In both sections, the Jahrom Formation unconformably overlies the upper part of the Gurpi Formation and conformably underlies the Pabdeh Formation. Based on microscope observations and fossil contents, eight microfacies are determined in four facies belts, that extend from tidal flat to deep open marine on a ramp environment. These facies contain:1)Mudstone. 2)Rhaphydionina polymorphina wackestone. 3)Hyaline-porcelanouse faraminifera wackstone. 4)Red algae packstone. 5)Lare hyaline foraminifera wackestone 6)Red algae planktonic foraminifera wackestone. 7) Planktonic-small hyaline foraminifera wackestone.8)Planktonic mudstone. Among these, only the two facies, Planktonic-small hyaline foraminifera wackestone and Red algae-planktonic foraminifera are not common between the two sections. Based on the foraminifera, an age of Early –Middle Eocene is quoted to the formation at this section.
Abbas Dehkar; Vali Ahmad Sajjadian; Mohammad Reza Noora; Kazem Shabani Goorji
Abstract
The Fahliyan Formation of Khami Group is hosting important hydrocarbon reserves in Iran and also is a main reservoir rock in the Abadan Plain oil fields which is Neocomian in age. In the studied wells its thickness is about 406 meters. In the Abadan Plain, the Fahliyan Formation transitionally overlies ...
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The Fahliyan Formation of Khami Group is hosting important hydrocarbon reserves in Iran and also is a main reservoir rock in the Abadan Plain oil fields which is Neocomian in age. In the studied wells its thickness is about 406 meters. In the Abadan Plain, the Fahliyan Formation transitionally overlies of the Garau Formation and its upper boundary changes into the Gadvan Formation. According to thin sections examinations prepared from cores analysis 11 microfacies is recognized by various facies including dolostone and dolomudstone of tidal flat, skeletal wackestone to packstone of the open and restricted lagoon, bioclastic intraclastic grainstones, peloid grainstone and coralinrudist-algae grainstone (boundstone) of the barrier setting and fine grained echinoderm rudist bearing deposits of the slope. high frequency of core facies belong to restricted and open marine lagoon deposits composed of benthic foraminifera, shell fragments and peliods. They are often observed in wackestone to packstone fabrics. The remained rock facies is composed of the bioclastic skeletal lime grainstones characterizing by large rudists and echinoderm debries which are interpreted to constitute the platform margin in this well. Tidal flat dolomudstone with a few bioclast contribute, which they often show moderate reservoir quality.
T. Binazadeh; A. Binazadeh; T. Vafaei
Abstract
The Asmari Formation is a thick carbonate sequence in Zagros foreland basin (southwest of Iran). It was deposited during Oligocene – Early Miocene ages. The formation with a thickness of 233m cropped out in the Dashtroom section (15 km south of Yasuj). This formation was studied from microfacies, ...
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The Asmari Formation is a thick carbonate sequence in Zagros foreland basin (southwest of Iran). It was deposited during Oligocene – Early Miocene ages. The formation with a thickness of 233m cropped out in the Dashtroom section (15 km south of Yasuj). This formation was studied from microfacies, sedimentary environment and biostratigrarphy point of view. Study of benthic foraminifera led to recognition of 23 genera and 32 species. In general, three assemblage biozones were recognized in this formation, consisting of: 1. Lepidocyclina- Operculina- Ditrupa assemblage zone 2. Miogypsina– Elphidium sp., Peneroplis farsensis assemblage zone 3. Borelis melo curdica- Meandropsina iranica assemblage zone An age of Early Oligocene (Rupelian- Chattian)- Early Miocene (Burdigalian) is suggested for the formation at the study area. Based on laboratory studies, nine microfacies related to three subenvironments (lagoon, bar and open marine) were identified. This study revealed that, the Asmari Formation deposited on a homoclinal epicontinental carbonate ramp.
S. M. Hamidzadeh; A. Babazadeh; B. Asgari – Pirbaluti; A. Solgi
Abstract
The Asmari Formation was measured and sampeled in Ghar-e Agha Seyyed at Farsan area in order to determine sedimentary environment based on facies analysis. In the study area, the Asmari Formation has a thickness of 183 m and conformably underlained the Pabdeh Formation. Based on microfacies studies, ...
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The Asmari Formation was measured and sampeled in Ghar-e Agha Seyyed at Farsan area in order to determine sedimentary environment based on facies analysis. In the study area, the Asmari Formation has a thickness of 183 m and conformably underlained the Pabdeh Formation. Based on microfacies studies, 8 microfacies were recognized such as:1) Porcelanouse foraminifera – bioclastic – red algal wackestone / packstone, 2) Rotalia grainstone, 3) Bioclastic –red algal grainstone, 4) Red algal – coral boundstone, 5) Red algal wackestone (Floatstone), 6) Red algal –large hyaline foraminifera – intraclast packstone, 7) Red algal – bioclastic - large hyaline foraminifera wackestone / packstone, 8) Large hyaline foraminifera packstone. These microfacies represent three facies belts including Inner ramp, Middle ramp and Outer ramp. On the other hand, based on the presence of benthic foraminifera, the age of the Asmari Formation is related to Oligocene (Rupelian – Chatian).
L. Azad Shahraki; H. Rahimpour Bonab; M. Ranjbaran; A. Kangazian
Abstract
The Lower Cretaceous (Neocomian) carbonates of the Fahliyan Formation are considered as important reservoir rocks in the Zagros Basin. In this study, the sedimentary successions of this formation in Lar (620m thick) and Khami (517m thick) anticlines, located in the Izeh zone, were investigated to analyze ...
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The Lower Cretaceous (Neocomian) carbonates of the Fahliyan Formation are considered as important reservoir rocks in the Zagros Basin. In this study, the sedimentary successions of this formation in Lar (620m thick) and Khami (517m thick) anticlines, located in the Izeh zone, were investigated to analyze microfacies, depositional environment, and diagenetic phenomena. Based on petrographic studies, 16 microfacies related to five facies belts of tidal flat, lagoon, carbonate shoal, mid ramp and outer ramp were recognized. Grainstone microfacies were found more abundant in the Lar stratigraphic section than the Khami section. Lack of turbidite deposits and reefal facies, and transitional changing of the facies show that the Fahliyan Formation was deposited in a homoclinal carbonate ramp. Abundance of mud dominated facies and rarity of high energy facies (like shoal facies) show that the ramp was a leeward one. According to petrographic studies, the main diagenetic features of the carbonates were micritization, cementation, dissolution, neomorphism, compaction, fracturing, and dolomitization. Due to deposition in the photic zone and high sedimentation rate, the thickness of the Fahliyan Formation in both stratigraphic sections is considerable, but based on the drawn isopach map, the thickest succession of the formation is found in the Lar section. Therefore, the Lar area is considered as the depocenter of the Fahliyan Formation. Difference in the thickness of the Fahliyan successions of Lar and Khami, most probably, is caused by the syndepositional activity of the north-south trending basement faults (like Kazeroon fault) in the region. Also, difference in the quantity of the burial compaction of the carbonate successions (caused by facies and diagenetic differences) played a role in secondary (burial) thickness changes.
S.A Babazadeh; M Rahmati
Abstract
Carbonate sedimentary rocks equivalent to Asmari Formation containing thick and thin bedded and massive limestones with a thickness of 160m studied in Posht-Darband, Hamadan. The base of the sedimentary sequence begun with a transgressive conglomeratic horizon. This horizon is composed of rock ...
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Carbonate sedimentary rocks equivalent to Asmari Formation containing thick and thin bedded and massive limestones with a thickness of 160m studied in Posht-Darband, Hamadan. The base of the sedimentary sequence begun with a transgressive conglomeratic horizon. This horizon is composed of rock fragments such as cherts, schists and fossiliferouslimestones which are derived from adjacent old rock units. The lower contact of conglomerate horizon overlains the metamorphic rocks and the upper contact is covered by alluvium. Based on the study of thin sections from Asmari Formation, two main facies belts containing inner and middle ramps are recognized. The inner ramp composes restricted lagoon, rotalid shoal, protected lagoon and patch reef whiles the middle ramp contains proximal, middle and distal parts respectively. Based on microscopic studies, eight microfacies are presented which are consist of; 1-Large perforate foraminifera-bioclastwackestone, 2-Perforate foraminifera-red algal-bioclastpackstone/grainstone, 3-Coralgal-bioclast packstone/grainstone, 4-Coral-redalgal packstone/grainstone, 5-Imperforate foraminifera-pelloid-bioclastpackstone, 6-Rotalia grainstone, 7-Perforate-imperforate foraminifera packstone/grainstone and 8-Miliolid-bioclast-intraclast packstone. They are deposited in seven sedimentary environments. According to microfacies, this formation is distributed from tidal flat to middle ramp. The Chatian (Late Oligocene) age is attributed to these carbonate rocks based on benthic foraminifera recorded.
S.A Babazadeh; M Ghavidel-Syooki; H Ghasabi
Abstract
The Asmari Formation is well-exposed at Kuh-e-Mish, locating at Gorg-Darreh area (The Zagros fold-thrust belt). In this area, the true thickness of Asmari Formation is 480m. This formation was studied for its microfacies analysis in Gorg-Darreh area (kuh-e-Mish). In this study, seven microfacies was ...
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The Asmari Formation is well-exposed at Kuh-e-Mish, locating at Gorg-Darreh area (The Zagros fold-thrust belt). In this area, the true thickness of Asmari Formation is 480m. This formation was studied for its microfacies analysis in Gorg-Darreh area (kuh-e-Mish). In this study, seven microfacies was recognized within this formation. These microfacies belong to the tidal flat, restricted lagoon, protected lagoon, patch reef, foreslope, basin sub-environments. A carbonate ramp is suggested for depositional environments of the Asmari Formation. Likewise, distributions of foraminifers of this formation were studied in order to determine the age relationships of the Asmari Formation. In this study, 45 species belonging to 41 genera were identified. In general, three assemblage biozones were recognized in this formation, consisting of Lepidocyclina – Operculina - Ditrupa Assemblage Zone, Peneroplis evolutus - Austrotrillina howchini Assemblage Zone and Borelis melo curdica – Meandropsina iranica Assemblage Zone. Therefore, based on these assemblage biozones, the Asmari Formation is assigned to late Oligocene (Chattian) – early Miocene (Aquitanian- Burdigalian).
M Hajian Barzi; S.M Aleali; D Falah Kheyrkhah; M Falah Kheyrkhah
Abstract
The Middle- Late Triassic Dashtak Formation acts as one of the best seal for giant gas reservoirs entrapped within the Dehram group inthe Southwest of Iran and the northern Persian Gulf because ofthick anhydrite deposits. The facies analysis of Dashtak Formation led to recognition of 14 microfacies, ...
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The Middle- Late Triassic Dashtak Formation acts as one of the best seal for giant gas reservoirs entrapped within the Dehram group inthe Southwest of Iran and the northern Persian Gulf because ofthick anhydrite deposits. The facies analysis of Dashtak Formation led to recognition of 14 microfacies, which are related to coastal plain, sabkha)supratidal(, tidal flat,lagoon, and shoal environments. Examination of the vertical and lateral facies changes and thire comparison with their modern and ancient counterparts, all indicate that the Dashtak Formation was deposited in a shallow carbonate ramp platform. The sequence stratigraphic studies showed that the Dashtak Formation consists of four third-order depositional sequences, each consisting of the transgressive and highstand systems tracts. The thickness of this formation increases from the Kuh-e Surmeh toward the boreholes d, c, b and a. A strontium isotope dating of the Dashtak Formation indicated a Triassic age from Ansian to Norian stages.
L Amirbahador; H Rahimpour-Bonab; M Arian
Abstract
This study is focused on the microfacies and facies associations in the 540 meter-thick interval of the Late Permian Upper Dalan reservoirs in the South Pars Gas Field using the petrographic studies, image analysis techniques and quantitative analysis of the constituting components. The petrographic ...
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This study is focused on the microfacies and facies associations in the 540 meter-thick interval of the Late Permian Upper Dalan reservoirs in the South Pars Gas Field using the petrographic studies, image analysis techniques and quantitative analysis of the constituting components. The petrographic studies led to the recognition of 15 microfacies that formed in four facies associations: peritidal, lagoon, shoal and off shoal. Due to the high frequency of the shoal facies in the Upper Dalan, those have been investigated in details. The relative sea-level changes during deposition of the Upper Dalan member were examined using the vertical microfacies and facies association’s variations. The main focus of this study is to investigate the microfacies variations and depositional environment evolutions in the Upper Dalan member in response to the relative sea-level changes. The frequency analysis of the facies revealed that during the Late Permian, a major fall has been occurred in relative sea-level recorded in the lower (K4 unit) and upper (K3 unit) parts of the Upper Dalan member. In these intervals, the facies change from ooid-bioclastic shoals to the alternative layers of shoal-lagoon-peritidal facies. As well, anhydrite precipitation and dolomitization are prominent diagenetic features, which are indications of climate change. The facies variations were used to reconstruct the relative sea-level changes during deposition of the Upper Dalan member in the South Pars Gas Field. As a result, two and a half third-order and 12 fourth-order cycles have been distinguished.
S.A Aleali; H. Rahimpour-Bonab; S. R. Moussavi -Harami; D. Jahani; A. Asadi-Eskandar
Abstract
The Early Triassic carbonates of Kangan Formation are major gas reservoirs in the Southwest of Iran and the northern Persian Gulf. Facies analyses of Kangan Formation led to recognition of 13 microfacies which are related to tidal flat, lagoon, shoal and open marine environments. Examination of vertical ...
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The Early Triassic carbonates of Kangan Formation are major gas reservoirs in the Southwest of Iran and the northern Persian Gulf. Facies analyses of Kangan Formation led to recognition of 13 microfacies which are related to tidal flat, lagoon, shoal and open marine environments. Examination of vertical and lateral facies changes and thire comparison with their modern and ancient counterparts, all indicate that Kangan Formation were deposited in a shallow carbonate ramp platform similar to the present day Persian Gulf. The sequence stratigraphic studies showed that the Kangan Formation consists of two third order depositional sequences (in the A and B wells), each consisting of transgressive and highstand systems tracts. The lower boundary of the first sequence is a type 1 unconformity, but other boundaries are type 2 unconformity. Typical reservoir zone in the Kangan Formation is dominated in early highstand systems tract deposits and concentrated in shoal grainstone facies. However, in this paper, typical intervals such as sequence boundaries, maximum flooding surfaces, stacking patterns and system tracts were studied.
M. H. Adabi; R. Abbasi; H. Ghalavand
Abstract
In this investigation Dariyan Formation with the age of Lower Cretaceous (Aptian- Albian) were studied for geochemical and sedimentology characteristics in the surface section at Kuh-e Siyah Anticline and subsurface section Sabzpushan well number 1. Based on petrographical studies 12 microfacies identified ...
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In this investigation Dariyan Formation with the age of Lower Cretaceous (Aptian- Albian) were studied for geochemical and sedimentology characteristics in the surface section at Kuh-e Siyah Anticline and subsurface section Sabzpushan well number 1. Based on petrographical studies 12 microfacies identified which are belonging to 5 facies belt, such as: intertidal, lagoon, shoal, shallow open marine and deep open marine. The observed facies patterns indicated a carbonate ramp depositional environment. Important diagenetic processes were observed in Dariyan Formation including cementation, physical and chemical compaction and replacement processes such as pyritization and silicification. Prosities in these sections are secondary, including vuggy, fracture and channel types. Major and minor elements and carbon and oxygen isotopes studies are indicated that aragonite was original carbonate mineralogy for this Formation. The plots of elemental values also are illustrated that mainly burial diagenetic processes have been affected this formation in semi- close to semi- open system. A temperature calculation based on the heaviest oxygen isotope value indicates that the very early, shallow burial temperature was around 28.5°C during Dariyan carbonate deposition.
M. A. Salehi; M. H. Adabi; H. Ghalavand; M. Khatibi-Mehr
Abstract
The Fahliyan Formation with the age of Lower Cretaceous (Berriasian-Hauterivian) were studied for microfacies analysis, diagenesis and original carbonate mineralogy in the type section at Fahliyan Anticline and subsurface section in well number 55 of Gachsaran Oil Field. Petrographic studies led to the ...
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The Fahliyan Formation with the age of Lower Cretaceous (Berriasian-Hauterivian) were studied for microfacies analysis, diagenesis and original carbonate mineralogy in the type section at Fahliyan Anticline and subsurface section in well number 55 of Gachsaran Oil Field. Petrographic studies led to the recognition of 10 microfacies that were deposited in four facies belts: tidal flat, lagoon, shoal and open marine. The observed facies patterns indicated a carbonate rimmed-shelf depositional environment. Recognition of different type of cements shows that the Fahliyan Formation has mostly undergone meteroric diagenesis. Major and minor elements and carbon and oxygen isotope values indicate that aragonite was the original carbonate mineralogy in the Fahliyan Formation, and suggests that alteration occurred in a closed diagenetic system, with low water/rock interaction.
M. H. Adabi; M. Khatibi Mehr; A. Moallemi; A. Sadeghi; M. A. Salehi
Abstract
The Ziyarat Formation is an Upper Paleocene to Middle Eocene carbonate sequences, located in North of Tochal Village (south-east of Tehran), near Emam Zadeh Abdollah. The Ziyarat Formation with the total thickness of 212.5 m conformably overlies the Fajan conglomerate and is overlain by greenish tufaceous ...
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The Ziyarat Formation is an Upper Paleocene to Middle Eocene carbonate sequences, located in North of Tochal Village (south-east of Tehran), near Emam Zadeh Abdollah. The Ziyarat Formation with the total thickness of 212.5 m conformably overlies the Fajan conglomerate and is overlain by greenish tufaceous siltstone of the Karj Formation. Petrographic studies led to the recognition of 11 microfacies. Different facies and evidences such as the absence of reefal facies, calciturbidite deposits, and widespread tidal flat deposits indicate that the Ziyarat Formation was deposited in a homoclinal carbonate ramp environment. Micritization, cementation, compaction, neomorphism, dissolution, dolomitization, fracturing and silicification are the major diagenetic processes in the Ziyarat Formation, occurring in meteoric and burial diagenetic environments. Major and minor elements and oxygen and carbon isotope values indicate that Ziyarat carbonates were deposited in a shallow warm water tropical environment and original carbonate mineralogy was aragonite. Bivariate plots of Mn versus Sr/Ca and δ18O illustrate that Ziyarat limestones were affected by open system diagenesis with high water/rock interaction. Early burial diagenetic temperature calculation based on heaviest oxygen isotope values of micrite and δw of Eocene seawater of 0.85 SMOW, shows that temperature was around 39˚C. Cathodluminescence studies of carbonate cements illustrated dull luminescence, because these carbonates afftected by both meteoric and burial diagenesis, and thus typical yellow to orange luminescence and zonations, evidence of meteoric diagenesis, are absent. This statement is confirmed by isotropic evidences.
S.H. Vaziri; D. Jahani; M. Safdari; F. Chegeni
Abstract
The Ilam Formation in southwestern Khorram Abad with a thickness of up to 204 meters consists of uniform limestones with Middle Turonian to Early Campanian age which were deposited in a continuous sedimentation process. In this section, the Ilam Formation has continuous ...
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The Ilam Formation in southwestern Khorram Abad with a thickness of up to 204 meters consists of uniform limestones with Middle Turonian to Early Campanian age which were deposited in a continuous sedimentation process. In this section, the Ilam Formation has continuous and transitional contacts with the Sourgah Formation in the lower boundary and the Gurpi Formation in the upper boundary. In the present study, 9 genera, 30 species and 2 biozones of the planktonic foraminifera have been recognized. The Ilam Formation in the studied section consists of a shaly facies and three carbonatic microfacies include mudstone, wackestone and packstone containing planktonic foraminifera. Shaly facies and mentioned microfacies were deposited in deep-open marine, which formed in a quiet environmental condition and increased environmental energy in microfacies with mudstone texture toward microfacies with wackestone and packstone textures. Whereas in the studied section recognized microfacies are not related to parts of continental shelf,such as ; bar, lagoon and tidal flat, therefore it could be said that, the studied area was part of profound depositional basin in Middle Turonian to Early Campanian.
