Gharif Formation
The Gharif Formation is a geologic formation in Oman. It preserves fossils dating back to the Permian period. The Gharif clastic reservoirs are an important hydrocarbon production unit, and the formation is a major producing oil and gas reservoir in Oman. Stratigraphy The subsurface Gharif Formation has been informally divided into 3 members (Lower, Middle and Upper) by geologists from Petroleum Development Oman. Though these members may be difficult to distinguish in certain localities due to rapid lateral facies changes, differential incision, salt movement or erosion, multiple studies have shown that these 3 members can be correlated on a regional scale. Lower Gharif Member The lower member is about 65 m (214.5 ft) thick in north and central Oman. It has been split into 3 submembers: Lower Gharif submember-1 unconformably overlies the Al Khlata Formation and is made up mostly of cross-bedded quartz sandstone. Locally, crinoid and brachiopod remains can be found. Though its thickness varies across central Oman, it is generally about 25 meter thick and does not exceed 30 meters. Lower Gharif submember-2 (or the Maximum Flooding Shale) contains bioturbated lime-mudstones and is under 10 meters thick. Lower Gharif submember-3 (also known as the Haushi Limestone) is about