عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In this research, in order to investigate Paleoecology, carbonate associations and determine PB-NB boundary surfaces with stage boundaries in one of the Marun oilfields 150 thin sections have been studied. Following the identification of the microfacies and sedimentary environments some paleoeological parameters such as salinity, light, nutrient, depth, hydrodynamic energy, the nature of substrate, temperature, oxygen, symbiotic, reproduction and nutrient strategy were analysed. In the studied well, the Asmari Formation successions have been deposited from normal to hypersaline, oligophotic to euphotic and oligotrophic to eutrophic conditions. Deep parts of the basin with low hydrodynamic energy, soft and stable substrate contain foraminifera with thin and elongate tests, the shallow parts of the middle ramp (proximal) and shoal with high hydrodynamic energy, hard and unstable substrate include thick-wall, lenticular hyaline benthic foraminifera and porcelaneous ones with thick walls are distributed in the lagoon facies belt. The high abundance of the large benthic foraminifera, coralinacea red algae and coral fragments indicate warm and tropical to subtropical environments during the deposition of the Asmari Formation. High proportion of the Epifaunal to Infaunal benthic foraminifera in the studied well suggest an oxygenated marine environment. In addition in this research 4 carbonate associations including Nanofer, Rhodalgal, Foralgal and Foramo were recognized. Finally, 4 positive boundary surfaces (PB) and 5 negative ones (NB) were introduced that some of them correlate well with stage boundaries.