Biostratigraphy and Paleoecology of the Sinjar Formation (Late Paleocene- Early Eocene) in the Dokan and Sinjar Areas, Iraq

Biostratigraphy of the Sinjar Formation is investigated in two sections (Dokan and Sinjar)from northeastern and northwestern Iraq, respectively. Two hundred samples from all thelimestones and marl that form the main lithological components of the studied sections werecollected. The studied limestones and marl are rich in microfossils. Through thin sections, wewere able to identify thirty species of benthic foraminifera and fifteen species of othermicrofossils (coral, algae, mollusca, bryozoa, and echinoids) at Dokan section, and fifty-onespecies of benthic foraminifera and thirty species of other microfossils at Sinjar section. 3biozones were distinguished from both sections 1-Biozone A: Kathina sp.- Lockhartia huntiAssemblage zone (SBZ 5) (Dokan section); (Kathina pemavuti - Lockhartia hunti Assemblagezone (Sinjar section), 2- Biozone B: Idalina sinjarica Total Range zone (SBZ 6-7) and 3-Biozone C: Alveolina globosa- Alveolina pasitisilata Concurrent Range Zone (SBZ8-10).These zones indicate the Late Paleocene –Early Eocene age of the Sinjar formation. Thebiostratigraphic correlations in the studied sections are based on benthic foraminiferalzonations. Showed the correlation comparison between the biostratigraphic zones of thecommonly used benthic zonal scheme around the Late Paleocene -Early Eocene in and outsideof Iraq. paleoecological studies suggest that the carbonate sedimentation of the SinjarFormation thrived in 18-25oC, with mesophotic to oligophobic light, under an oligotrophic tomesotrophic middle ramp environment with normal marine to slightly saline and at waterdepths from 40 - 80 m. Stable isotopic carbon (δ13C) and oxygen (δ18O) data revealed generallyhot conditions with high productivity during the deposition of the Sinjar Formationaccompanied by an abrupt change in paleoenvironmental conditions across the Paleocene-Eocene contact.