Document Type : Original Research Paper


1 Ph.D. Student, Department of Geology, Faculty of Scince, University of Isfahan, Isfahan, Iran

2 M.Sc. Student, Department of Geology, Faculty of Scince, University of Shahid Bahonar, Kerman, Iran

3 M.Sc., The Geological Survey of Iran in Kohgiluyeh and Boyer-Ahmad Province, Yasuj, Iran


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.


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