Abstract
The study involves the Euphrates Formation in the area between Fuhaimi and Al-Qaim valleys in the western desert of Iraq. The Formation was divided into six informal units depending on various lithological properties. Facies analysis reveals the presence of the following microfacies, from bottom to top respectively; pelletal lime packstone, pellitoidal lime grainstone, oolitic lime grainstone, benthonic lime packstone and dolomitized lime mudstone microfacies. These microfacies, in addition to some geochemical properties were used to interpret the depositional environments, which are ranging from shelf, low water energy restricted and lagoonal environment to relatively high water energy open marine.