ThepredorninantmicrofaciesoftheAsmariFormationat Dehdezareaare: (1) globigerinidbioclasticwackestonetopackstone, (2) globigerinid laminated wackestone, (3) coral and coralline algal boundstone, (4) bioclastic-lithoclastic wackestone to packstone, (5) foraminifera bioclasticwackestone to packstone,(6) foraminiferagrainstone, (7) peloid wackestoneto packstone, and (8) peloid bioclastic grainstone.Based on microfacialcharacteristicsthe AsmariFormationwas depositedat the study area as a transgressive sequence from base to top from shoal to restrictedand normal marine shelf to fore-slope to basin margin deposits. Deposition continuedwith a regressive cycle from basin margin to fore-slopeand restricted shoal and finally to restrictedplatformsediments.Microfaciesanalysisand faciesinterpretations acrossthecentralhighZagrossuggeststhattheAsmariFormationwasdepositedmostlyinavery shallowmarine environmentat the easternmarginofthe basin. Depositionof a thick sequenceofpelagic sedimentsindicatesdeeper marine conditionsexistedat the centralparts of thebasinduringBurdigalian. Westward, the exposedAsmariFormationreflectsan occurrenceof very shallow marine condition prevailed during Oligo-Miocene. Finally deposition of the Asmari Formation took place under transition environmentat farwest of central Zagros Basin.

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The Late Paleogene-Early Neogene succession studied at the Khunnug area, on the northern flank of the Persian Gulf, includes upper part of the Jahrum, lower and middle parts of the Asmari and the most lowest part of the Gachsaran Formations, The upper part of the Jahrum Formation is characterized by limestones from the Dictyoconus-Coskinolina-Orbitolites and Globorotalia renzi-Globigerina assemblage zones of the Middle Eocene. The lower part of the Asmari Formation is gypsiferous marly, dolomitic limestones, and limestones from the Nummulites-Operculina assemblage zone of the Middle Oligocene (Rupelian) age. The middle part ofthe Asmari Formation is gypsiferous dolomitic limestone and limestone from the Archaias-Peneroplis assemblage zone of Early Miocene (Aquitanian) age. The lower part of the Gachsaran Formation is characterized by thick-bedded anhydrite and thin beds of dolomitic marls, with miliolids, reflects deposition during to Late Aquitanian through Burdigalian.Within the above succession, two conformable non-conformities correlatable to Priaborian-Lattorfian and Chattian times is recognized. Also, unlike most of the Zagros Basin, marine carbonate deposition (correlatable to the upper parts of the Asmari Formation) is replaced by the evaporitic facies of the Gachsaran Formation during that accumulated the Burdigalian time.

In this research, biostratigraphy and paleoecological implications related to the carbonates of the Asmari Formation located at the Naura anticline, Interior Fars of the Zagros Basin, Iran, are discussed. The Asmari Formation at the study area is Rupelian-Chattian in age. Age was determined by the occurrence of 22 genera and 41 species which led to identification of four faunal assemblages: (1, Globigerina-Tuborotalia cerroazulensisHantkenina; 2, Nummulites vascus-Nummulites fichteli; 3, Lepidocyclina-Operculina-Ditrupa; 4, Archaias asmaricusArchaias hensoni-Miogypsinoides complanatus). Based on faunal associations and biofacies analysis with emphasize on large benthic foraminifera and coralline red algae communities, the following paleo-ecological factors are defined for deposition of the Asmari Formation at the study area: water salinity of 34 to more than 50 psu, depth zones of 0-35 m of inner and middle part of proximal open shelf, 35-150 m of middle open shelf and more than 200 m of outer open shelf, water temperature of 18-25°C in a tropical to sub-tropical environments, oligophotic to near mesotrophic conditions and grain association communities of foralgal and rhodalgal.