نانواستراتیگرافی و پالئواکولوژی سازند پابده در شمال غرب حوضه زاگرس در برش ایلام

Abstract

The aim of this research was to interpret environmental conditions of the Pabdeh Formation in Ilam section, North West Zagros basin, based on calcareous nannoplankton. According to identified biozones which is equivalent to NP10-NP25 biozones of Martini (1971), the age of Pabdeh Formation in studied section is Early Eocene – Late Oligocene. Abundance of Discoaster and Sphenolithus in the lower part of section indicates an oligotrophic condition in sedimentary basin which is related to global warming. Toward the top of section, the Cyclicargolithus floridanus, Sphenolithus moriformis, Coccolithus pelagicus, Reticulofenestrid nannofossils are dominant. On the other hand, the presences of genera Reticulofenestra, Cyclicargolithus, Dictyococcites that are taxa of temperate and cold water, indicate mesotrophic – eutrophic conditions in the upper part of section. Increasing of Discoasters shows warming trend during the Late Oligocene time.