The Garau Formation is located in the Zagros Basin that has continous sedimentation during Cretaceous (Valanginian-Cenomanian) in northwest Iran and central-east of Iraq. The importance of this formation returns to its high potential hydrocarbon production at one of the most oil system productive regions in the world. However, this basal Formation is a possible source for some of the important reservoirs in Iran and Iraq. The counterpart formation of Garau in the East of Iraq is called Balambo Formation. Both formations laterally were passed into shallower basin.