Biostratigraphy and Microfacies of the Asmari Formation in The Zagros Basin:Age and Environmental Correlation
Subject Areas :Keywords: Asmari Formation Biostratigraphy Microfacies paleoenvironment Zagros Basin,
Abstract :
In this research ,biostratigraphy,microfacies and paleoenvionment of the Asmari Formation in the fars provingce(Tang-e Abolhayat,Naura anticline, south-west of Firozabad,Khormuj anticline),High Zagros(Shoorom anticline), IZeh zone (Mokhtar anticline),Dezful Embayment(Tang-e Anbar sepid, Dill anticline, Khaviz anticline,Aghajari oil field ) and Lurstan province(Mamulan,Sepid-dasht,Dehluran and kabirkuh-Darreshahr0,were reviewed and revised for the comprehensive understanding of age and depositional environments. The Globigerina spp.-Turborotalia cerroazulensis-Hantkenina and Nummulites vascus-Nummulites fichteli assemblage zones (Rupelian) are present in Fars province. The dominated microfacies within the Asmari Formation of the Rupelian time are bioclast planktonic, nummulitidae lepidocyclinidae wackestone-packstone, of an outer and middle ramp depositional setting. The Archaias asmaricus-archaias hensoni-Miogypsinoides complanatus assemblage zone (Chattian)is present in Fars ,High zagros,Izeh and Dezful Embayment provinces. The dominated microfacies within the Asmari Formation of the Chattian time are bioclast perforate-imperforate foraminifera wackestone-packstone and mudstone, of an inner ramp depositional setting . The Miogypsina-Elphidium sp. 14-Peneroplis farsensis assemblage zone(Aquitanian) is present in High Zagros, Izeh ,Dezful Embayment and parts of the Fars and Lurestan provinces.The dominated microfacies within the Asmari Formation of the Aquitanian time are perforate-imperforate foraminifera bioclast wackestone –packstone,grainstone,and mudstone,of an inner ramp depositional setting. The Borelis melo curdica –Borelis melo melo assemblage zone (Burdigalian) is present in most areas. But it slightly occurs in fars province. The microfacies of the Asmari Formation during Burdigalian are similar to those of Aquitanian .In sepid-dasht and Tang-e Anbar Sepid sections due to presence Globigerina spp. Assemblage zone and planktonic forminifera wackestone-packstone facies, an outer ramp depositional setting is also suggested.