Microfacies, Sequence stratigraphy, Facies analysis and Sedimentary environment of Neocomian in Kuh-e-Siah section (Arsenjan area, SW of Iran) (original) (raw)
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Open Journal of Geology, 2013
The Fahliyan Formation is a carbonate sequence of Lower Cretaceous (Berriasian-Hauterivian) in age and was deposited in the Zagros sedimentary basin. This formation is a part of Khami Group and is a reservoir rock in Zagros Basin. This formation was investigated by a detailed petrographic analysis in order to clarify the depositional facies and sedimentary environment in the Kuh-e-Gadvan in Fars Province. Petrographic studies led to the recognition of nine microfacies that were deposited in four facies belts: tidal flat, lagoon, and barrier and shallow open-marine. An absence of turbidite deposits, reefal facies, and gradual facies changes indicate that the Fahliyan Formation was deposited on a carbonate ramp.
2011
Fahliyan Formation (Neocomian) is one of the important hydrocarbon reservoirs for Khami group in southwest of Iran. This formation with 332m thickness in type section consists mainly of carbonate rocks. In this research, Fahliyan Formation was investigated in subsurface section of Azadegan borehole in the Dezful Embayment Lower boundary of Fahliyan Formation with Garau Formation is continuous and there is an uncontinuity between upper Fahliyan Formation with Gadvan Formation. Accurate to Petrographic studies and Interpretation of geophysics logs, 13 Microfacies and one shaly facies were recognized which compromise four facies associations. These from shoreline to basin are Tidal-flat, Lagoon, Bar and Open marine Facies Association. Combination of sedimentology, tectonic records and vertical facies changes of the Fahliyan Formation in the studied sections and in comparison with ancient and modern depositional environment, indicate the facies of this formation have been formed in shal...
Himalayan Geology
The Fahliyan and Gadvan formationsof Lower Cretaceous age (Neocomian-Early Aptian) exposed on Kuh-e-Surmeh section were studied in order to evaluate microfacies, depositional environment and sequence stratigraphy. Petrographic study led to recognition of 18 microfacies deposited in five subenvironment : pelagic, hemipelagic, middle shelf, inner shelf, coastal plain. Sequence stratigraphy assessment of these deposits revealed three depositional sequence of third order of which the two lower ones belong to the Fahliyan Formation and the third one related to the Gadvan Formation. Except for the lower boundary of the sequence, the other boundaries are type 2
2010
This study is focused on the sedimentary environments, facies distribution and sequence stratigraphy of the Santonian intervals (Ilam Formation of Bangestan Group) that host enormous hydrocarbon reserves in five giant and supergiant oilfields in the central and southern parts of the Dezful Embayment (SW Iran). This reservoir formation is investigated using detailed petrographic analysis assisted by microscopic image analyses to explain its depositional facies and sedimentary environment in the subsurface sections of this embayment. Petrographic studies led to the recognition of 18 microfacies that formed in four facies belts: inner ramp (including shoal facies and open to restricted lagoons), mid-ramp (including channels and patch reef talus facies), outer ramp and basin. To locate the approximate position of the studied wells in the conceptual depositional model, frequency analyses for facies associations are carried out. The studied intervals consist of two, thick shallowing-upward 3rd-order sequences. Facies variations of the Ilam Formation investigated throughout the studied oilfields using correlation in a sequence stratigraphic framework.
Gadvan and Darian formations are in the upper part of Khami group that has been deposited in the highland Zagros zone and the southern Margin of Neotethys. These formations outcrop in the south of Semirom (Agh-Dagh Mountain) consist of Orbi-tolina limestones and marly limestones with a Late Barremian-Aptian age and thickness of 520 meters. Based on field characteristics, petrographic and texture of facies, these rocks consist of Oregonian facies (Urgonian facies) with 12 carbonate microfa-cies which are deposited in Lagoon, barrier and shallow open marine. The absence of loss and flows of turbidities indicates that carbonate platform of Gadvan and Darian formations in the studied area are (Hmoklinal) platform type. Abundance of rudist (bivalves) and Peloid markers show that there is a Photozoan collection in tropical climates. In the above sedimentary succession, from a sequence stratigraphic perspective , three sedimentary cycles were recognized which deposited in a platform model. The Gadvan Formation overlies on Fahliyan Formation disconformable and is covered by Darian Formation gradual with reducing the amount of marl and increase of limestone. The Kazhdumi Formation is exposed disconformably with he-matite nodules and oxidized sediments over the Darian Formation. On the basis of petrographic studies, diagenetic process of Gadvan and Darian formations in the study area includes cementation, the physical and chemical density and replacement processes such as pyritation, ironies and silica. Porosity observed in the study area is mainly inter-granular porosity type, modular and vaggy.
Arabian Journal of Geosciences, 2022
The Fahliyan Formation is an important part of the Khami Group reservoir in the Zagros structural zone, particularly in the Dezful Embayment. The main objectives of this study are to investigate the microfacies, depositional environment and sequence stratigraphy based on petrographic data of six hundred and seventy thin sections and gamma ray log. Accordingly, 21 carbonate microfacies and two clastic lithofacies were recognized within the Fahliyan Formation, which were deposited in four distinct facies belts including open marine, shoal, lagoon and tidal flat. Based on facies characteristics and sedimentary features, a carbonate rimmed shelf setting was purposed. The predominant abundance of lagoon facies indicates that the study area is located in the shallow part and margin of Zagros structural zone during sedimentation of the Fahliyan Formation. The lower part of the Fahliyan Formation was deposited in a rimmed carbonate platform, and the upper part gradually passes to a mixed carbonate-clastic environment (Khalij Member of the Gadvan Formation). This transition is well documented in the upper parts of well H3. The Fahliyan Formation comprises two third-order depositional sequences in this oil field and could be subdivided into two parts including lower Fahliyan (Berriasian-Valanginian) and upper Fahliyan (Hauterivian-Barremian). Also based on foraminifers, two biozones including Pseudocyclammina lituus-Trocholina sp. zone (Valanginian-Barremian) and Choffatella-Cyclammina zone (Hauterivian-Barremian) were recognized.
Open Journal of Geology, 2016
Fahliyan Formation is importance in terms of Zagros stratigraphy since it is one of the oil reservoir rocks at the Jurassic-Cretaceous boundary. This rock unit consists of two types of deep and shallow facies in Zagros area. Recognition of bio-zones as well as discontinuity or continuity between the studied formation and the encompassed strata is taken into consideration. In order to study biostratigraphy on Fahliyan Formation, the stratigraphic section of Kuh-e-siah in the northeast of Fars Province was selected. In this section, Fahliyan Formation is measured 345 m consisting of thin to medium-bedded of limestone with the interbeds of sandy and dolomitic limestones. Fahliyan Formation conformably overlies Surmeh formation and underlies the marls of Gadvan formation. Vertical distribution of the identified foraminifers and calcareous algae confirms presence of 3 biozones in the sediments of Fahliyan Formation, as follows: 1) Calpionella alpina zone; 2) Pseudochrysalidina conica zone; 3) Pseudocyclammina lituus-Trocholina sp. assemblage zone. Based on Established biozones, the age of Fahliyan Formation in Kuh-e-Siah section was determined from Berriasian to Late Hauterivian.
International Journal of Basic and Applied Sciences, 2012
The Permian carbonates-evaporates Dalan Formation is one of the most important gas reservoir in the Zagros Basin. The Zagros are located on the boundary between the Arabian and Eurasian lithosphere plates and are the Orogenic response to a collision between Eurasia and advancing Arabia during the Cenozoic. The study area is located at the eastern part of Surmeh Mountain, ~120 km south of Shiraz in the Folded Zagros Zone. Dalan Formation at Surmeh Mountain, with a thickness of 650 meters, is formed of three lithostratigraphic units. These units, from bottom to top, consist of Lower Dalan, Nar Member and Upper Dalan. The careful examination of thin sections led to the recognition of six microfacies which was performed on the basis of skeletal and non-skeletal grains and matrix (fenesteal dolomitic mudstone, layered anhydrite, lagoonal skeletal wackstone/ packstone, fine-grained ooid, peloid grainstone with lagoonal skeletal debris, medium-grained ooid grainstone with oomoldic porosity, open marine fossiliferous mudstone). Microscopic and macroscopic evidences show that Dalan Formation facies can be divided into four facies belts, on the basis of depositional features, specific of carbonate platforms of homoclinal ramp type. These belts include tidal flats, lagoons, shoal and basin environments. Mohammad Bahrami et. al.
The aim of this research is to investigate facies and sedimentary environment of post-Devonian deposits and pre-carboniferous in Esteghlal Fireclay Mine in Abadeh, surrounded by Zagros Mountain. With a production of about 1 million tons per year, it has the largest reserves of fireclay in the Middle East. After choosing three stratigraphic sections of A, B, and C, and taking 250 samples manually, 10 facies belonging to five facies groups in tidal flat, lagoon, dam, open marine, and delta facies were identified; these 10 facies are: facies 1 (Mudstone with fenestral fabrics), facies 2 (Stromatolite bindstone), facies 3 (Wacke stone / Pelloid Bioclast Pack stone with various fossils), facies 4 (Packstone / Bioclast Grainstone) facies 5 (Packs tone /Bioclast grain stone with intraclast), facies 6 (Pack stone / Echinoid grain stone), facies 7 (Echinoid and Bioclast brachiopod rudstone), facies 8 (Pack stone / bioclast Wacke stone with various fossils), facies 9 as a Clastic facies (Silt stone), facies 10 as a Clastic facies (lichens). The ancient geography situation of this area can be explored through interpreting and an examining this micro-facies. Stratigraphic section (A) with 60 m thickness represents the sedimentation in deltaic environment outside the water (deltaic plain), stratigraphic section (B) with 120m thicknesses represents the sedimentation in deltaic environment underwater (forefront and end of the delta). Carbonated deposits in stratigraphic section (C) with 75m thicknesses is related to a carbonated platform type (Homoclinal ramp).