Biostratigraphy and paleoecology of the Asmari Formation at Tang-e Shivi, north-west flank of Nowdan Anticline in north of Kazerun (Interior Fars) and age correlation with three another sections in Costal Fars and Izeh Zone
Subject Areas :
1 - دانشگاه اصفهان
Keywords: Asmari Formation Biostratigraphy Paleoecology Benthic foraminifera ,
Abstract :
Abstract In this research, the Asmari Formation΄s benthic foraminifera at Tang-e Shivi north-western flank of Nowdan Anticline in north of Kazerun (Interior Fars), with geographic coordinates E: 51° 44' 58'' and N: 29° 47' 42'', have been studied in order to introduce assemblage zones, age and paleoecology and correlate the age of the Asmari Formation with sections in Costal Fars and Izeh Zone (Firozabad, Dill, Shagabil). Its upper and lower boundaries are comfortable with Gachsaran and Pabdeh formations. Three assemblage zones at the studied section were recognized based on benthic foraminifera and biostratigraphy study. Detected biozones reflect Oligocene (Rupelian and Chattian) and Miocene (Aquitanian) age for this studied deposits with 348 meters thickness. Assemblage zone 1, with Firozabad section and assemblage zone 2 with 3 other sections and assemblage zone 3 with Dill anticline are correlatable. Environmental parameters such as: salinity, light, nutrients, temperature and depth, have played a role concerning the distribution of foraminifera. Accordingly, the Asmari Formation deposited in a normal salinity to hyper salinity water, aphotic to euphotic and oligophy to eutrophy zones. Grain supported microfacies (O4, O5, B, L1, L2, L4, L5 and L7), support reservoir quality for the Asmari Formation in subsurface areas, next to the studies section. The carbonate grain association types of the study section are nanofer, rodalgal, foralgal and foramol.