Biostratigraphic and Lithostratigraphic Study of Fahliyan Formation in Kuh-E-Siah (Arsenjan Area, North-East of Fars Province)

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 stratais taken into consideration. In order to study biostratigraphy on Fahliyan Formation, the stratigraphic section of Kuh-e-siah in the north-east 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.

Boundary Between Upper Cretaceous and Lower Paleocene in the Zagros Mountain Ranges of Southwestern Iran

In the present study, over 3000 m of Upper Cretaceous sediments （Tarbur Formation） in seven stratigraphic, columnar sections were studied. The area is located in the Zagros mountain ranges of southwestern Iran, attributed to the converging continental Arabian Shield, and is interpreted as the result of subduction and collision. Based on foraminiferal studies of the Tarbur Formation in the sections, we have established many new biozones in the stratigraphic sections. However, investigations of the biozones indicate that there is no lithostratigraphic variation between the Upper Cretaceous and Lower Paleocene sediments in some of the studied sections. The concept of widespread formations and lithologic correlations is not applicable in this area, probably as a result of the tectonic unrest at that time. The biostratigraphic boundary between the Cretaceous and the Lower Paleocene is nevertheless well defined by the intraformational boundary in the sections.

Aptian biostratigraphy in South Zagros Basin, southwest Iran

The Khami group within the petroliferous Zagros Basin of Iran includes the Surmeh, Hith, Fahliyan, Gadvan and Dariyan formations. The Dariyan Formation, previously known as Orbitolina limestone is very signif-icant as a reservoir rock in the Zagros Basin. In this study, the age of the Dariyan Formation is examined based on biostratigraphic and paleontological investigations. 236 m of Dariyan Formation sediments in the sections at Kuh-e Rahmat （north） and Nour-Abad （west） of Iran were selected to study its biostratigraphy. According to the lithostratigraphic investigations, the Dariyan Formation in these sections is subdivided into three： lower, middle and upper, which include thin-bedded to medium-bedded and massive lime-stone. Micropaleontologic study of the Dariyan Formation has led to the recognition of two biozones in the Nour-Abad area and one biozone in the Kuh-e Rahmat stratigraphic column. Diagnostic foraminifera in these sections are as follows： Globigerinel oides algerianus Cushman and Ten Dam, Globigerinelloides fer-reolensis Moullade, Globigerinelloides maridalensis （Bolli）, Globigerinelloides paragottisi Verga and Permoli Silva, Hedbergel a aptiana Bartenstein, Hedbergel a excelsa Longoria, Hedbergel a luterbacheri Longoria, Hedbergella occulta Longoria, Hedbergella ruka （Banner et al.）, Hedbergella similis Longoria, Hedbergella trocoidea （Gandolfi）, Muricohedbergella delrioensis （Carsey）, Pseudoplanomalina cheniourensis Sigal, Con-icorbitolina conica d＇Archiac, Iraqia sp., Mesorbitolina parva Douglass, Mesorbitolina pervia Douglass, Meso-rbitolina ovalis Gorog and Arnaud-Vanneau, Mesorbitolina subconcava Leymerie, Mesorbitolina texana （Roemer）, Mesorbitolina ovalis-pervia Cherchi and Schroeder, Debarina hahounerensis Fourcade et al., Marssonel a trochus （d＇Orbigny）, Nezzazata sp., Orbitolina sp., Textularia sp.

The Role of Stratigraphy in Growth Strata Studies: A Case Study of the Early Cretaceous Deposits in the Persian Gulf, SW Iran

The growth strata was investigated in the Early Cretaceous deposits including Fahliyan, Gadvan and Dariyan formations in the Well 3 that is located between Qatar-Fars height and Hormuz Strait in Persian Gulf. This study is based on the lithostratigraphic analysis and microfossils distribution. Lithostratigraphically, the Well 3 is divided into three rock units including Fahliyan, Gadvan and Dariyan. Based on the microfossils content, the age of studied successions is Berriasian to Aptian. The comparison of seismic studies, lithostratigraphic analysis and microfossils distribution show that growth and generation of anticlines construct in the Early Cretaceous. As a result, the Fahliyan, Gadvan and Dariyan rock units have potential reservoir and oil trap.

Biostratigraphy,Microfacies and Depositional Environment of the Sarvak Formation at the Pyun Anticline(Zagros Basin,Southwest of Iran)

The Sarvak Formation is a carbonate sequence of Late Albian–Early Turonian age in Zagros Basin in Iran.In this investigation,the Sarvak Formation at the Pyun Anticline section(Izeh Zone)has been studied.It consists of 797 m thick limestone which overlies the Kazhdumi Formation conformably and underlies the Gurpi Formation unconformably at the Pyun Anticline.A very rich fossil association(85 genera and 132 species)characterizes the Pyun section.Based on the stratigraphic distribution of diagnosed foraminifera,five biozones are established:1,Muricohedbergella-Globigerinelloides sp.assemblage zone(Late Albian);2,Praealveolina iberica-Chrysalidina gradata interval zone(Early Cenomanian);3,Chrysalidina gradata-Cisalveolina fraasi(fallax)and C.lehneri interval zone(Middle Cenomanian);4,C.fraasi(fallax)and C.lehneri-Praetaberina bingistani assemblage zone(Late Cenomanian);5,Nezzazatinella picardi-MangashtiaDicyclina assemblage zone(Early Turonian).Based on the petrographic and sedimentological analyses,some 13 carbonate microfacies were identified.The investigated microfacies confirm a ramp-type paleoenvironment.These microfacies,from distal to proximal environments,consist of:MF1:planktonic foraminifera wackestone-packstone;MF2:Oligostegina planktonic foraminifera wackestone to packstone;MF3:planktonic-benthic foraminifers sponge spicules wackestonepackstone;MF4:rudist floatstone;MF5:rudist rudstone;MF6:bioclast intraclast grainstone;MF7:peloid intraclast grainstone;MF8:benthic foraminifers rudist grainstone-packstone;MF9:peloid bioclast grainstone-packstone;MF10:bioclast(benthic foraminifers)wackestone-packstone;MF11:peloid bioclast packstone;MF12:dacycladacea benthic foraminifera packstone-wackestone;MF13:miliolids wackestone-packstone.

Paleoenvironmental Distribution Patterns of Sequence Stratigraphy in the Paleocene-Eocene Deposits of Sekonj Trough Event (Central Iran)

The Paleocene-Eocene successions were studied in Sekonj and Abaregh sections and located in South of Kerman in order to determine the microfacies, depositional environment and sequence stratigraphy. The deposits in the studied area are mainly composed of limestone, sandstone, conglomerate and shale. The obtained data from the field and laboratory observations led to identification of 11 microfacies which represent the coastal, tidal flat, lagoon, barrier and proximal open marine which were deposited in a carbonate-siliciclastic ramp environment. The sedimentology evidences, vertical analysis of microfacies, facies and relative sea level changes represent that the Paleocene-Eocene succession deposits have two 3rd depositional sequences in the studied area. The sequence 2 cannot be recognized completely due to the lack of outcrop. Sequence stratigraphic studies show an upward shallowing trend corresponding to the global sea level changes from the base to the upward of the succession.

Diagenetic Aspects of the Lower Paleocene Sachun Formation Carbonates,Zagros Basin,Southwestern Iran

The Sachun Formation in the Zagros Mountains Ranges was sampled on the basis of changes in lithology and 150 vertically oriented thin-sections were prepared and subjected to detailed petrographic study. Evaporite, carbonate and shale/marl facies are identified here. These facies which have been laid in 4 facies belts of supratidal, intertidal, lagoon and barrier, deposited on a ramp platform. Petrographic studies showed that the Sachun Formation has had a complex diagenetic history. The following diagenetic events occurred in the carbonate microfacies： micritization, dissolution, silicification, dolomitization, hematitization, compaction, fracturing and stylolitization. The diagenetic features observed petrographically in the carbonate microfacies represent changes which took place under three diagenetic environments（eogenic, mesogenic, and telogenic） with three different marine, burial, and meteoric diagenetic conditions. The diagenetic sequence of events that affected the Sachun Formation includes micritization and micrite envelope features which have been reported from an eogenic/marine environment.

Biostratigraphy Study of Tarbur Formation(Upper Cretaceous) in Tang-E Kushk and East of Sarvestan(SW of Iran)

In this study, 465 m of Tarbur Formation in Tang-e Kushk and east of Sarvestan area stratigraphic sections are studied and 185 thin sections are provided and analyzed. Based on lithostratigraphic studies, Tarbur Formation in these two stratigraphic sections is divided into upper and lower parts. Lower part includes medium-bedded rudist limestones which is consist of iron nod- ules with Gastropoda. Upper part is made of light grey massive organodetrital limestone. Identified foraminifers of both studied sections are comprised of： Orbitoides media, Orbitoides triangularis, Orbi- tomes tissoti, Orbitoides orientalis, Orbitoides apiculata, Antalyna korayi, Rotalia skourensis, Dicyclina schlumbergeri, Nezzazatinella sp., Omphalocyclus macroporus, Trochospira sp., Siderolites calcitrapoides, Broeckinella sp., Lepidorbitoides socialis, Gavelinella pertusa, are detected, and also it has Dasycladacea of Salpingoporella dinarica, Salpingoporella turgida, Salpingoporella sp.. According to diagnosed fo- raminifera, the are determination of Tarbur Formation is assigned to Upper Maastrichtian.

Biostratigraphy of Albian Sediments(Kazhdumi Formation)in Zagros Area(Southwest of Iran)

To investigate biostratigraphy of Albian sediments(Kazhdumi Formation)in the Zagros Basin,280 samples in four sections were prepared which are nominated as Murshan-e-Bala,Fahliyane-Pain,Kupon and Tale-e-Afghani.Stratigraphic distribution of identified foraminifers confirms well developed orbitolinids which are associated with other Albian benthic foraminifers in all studied sections.The orbitolinids are recognized in surrounding strata[Dariyan(at the base which is marked by an oxidized zone)and Sarvak Formations(on the top,as gradtional contact)]as well as the Kazhdumi Formation.Obtained biostratigraphic data show that Early Albian is marked by the presence of Hemicyclammina sigali,which co-occurs with Mesorbitolina texana and Mesorbitolina subconcava,whereas Conicorbitolina conica and Meorbitolina parva support Late Albian age of the studied sections.Calcareous algae are associated with both benthic faunal assemblages.Albian planktons occur in the studied sections which are identified as Favusella washitensis and Calcisphaerula inomminata subzones.The stratigraphic position of planktons actually indicates vertical displacement in the sedimentary basin during Albian time.Other associated Albian pelagic foraminifera are identified which are obviously recognized in three sections of the Kazhdumi Formation.The presence of pelagic species in the study section of the Kazhdumi Formation indicates basement faulting during the Albian period.