Microfacies and the Depositional Environment of (Upper Oligocene-Lower Miocene) succession in the Anah area, northwest of Anbar Governorate, western Iraq was carried out.This study was conducted on Glass Markers twenty-eight samples of limestone collected from the section of Wadi Al-Khazgah.Azkand and Anah formations of the Upper Oligocene and Euphrates Formation of Lower Miocene were identified in this section, depending on the availability of benthic Foraminifera and microfacies of each Formation.
The depositional environment of the Azkand and Anah formations represents the environment of the reef, fore-reef, and back-reef, respectively, while the Pizza Tray environment of the Euphrates Formation represents the shore, restricted to open marine.14 sub microfacies types have been distinguished, which are Lepidocyclina Lime Packstone, Miliolids Lime Grainstone, Coral Lime Boundstone, Miliolids Lime Packstone-Grainstone, Rotalia- Heterostegina Lime Packstone, Gastropoda Lime Packstone, Miliolids Lime Packstone, Heterostegina Lime Wackstone, Miliolids Lime Wackstone, Dolomitized Mudstone, Lime Mudstone.