Yamama Fm
Type Locality and Naming
A number of short exposures on the Al Qusaij’a upland of Saudi Arabia. M. Steineke, R.A. Bramkamp and N.J. Sander, 1958 amend. R.W. Powers et al., 1966
Synonym:
Reference Section:
Q.P.C. Well Dukhan No. 26, lat. 25°26’58” N, long. 50°48’47” E, elevation 24.4 m (80 ft), completed 14.1.1952, between drilled depths 1553 and 1674 m (5095 and 5490 ft).
Lithology and Thickness
Top. 1. Limestone, light grey to buff, fine grained, porous to compact, pellety in lower part. 29 m (95 ft). 2. Limestone, grey, hard, fine grained, compact, pellety with occasional oolitic horizons; often includes coarse to fine detrital carbonate grains. 66 m (217 ft). 3. Limestone, light grey, chalky to very chalky in upper part, containing variable proportions of pellet debris. 25 m (83 ft). Base. Its thickness is 120 m (395 ft).
Relationships and Distribution
Lower contact
Upper contact
Lekhwair Fm; contact appears conformable in Qatar but regional evidence suggests that a considerable sedimentary hiatus could exist at this level. Boundary placed where clean, porous limestones of the Yamama are overlain by argillaceous limestones of the basal Ratawi.
Regional extent
The Yamama Formation exhibits a similar lithologic development in the subsurface throughout Qatar. To the east in Abu Dhabi it is predominantly lime mudstone and often difficult to distinguish from the Sulaiy Formation. The Yamama Formation can be traced north westwards through Saudi Arabia into Kuwait and South Iraq.
GeoJSON
Fossils
In 1. Pseudocyclammina aff. lituus (Yokoyama), Nautiloculina oolithica Mohler, Trocholina sp., Spirocyclina sp., Stromatopora aff. costai Osimo, Polyphylloseris cf. prae-turoniae (Zuffardi-Commerci). In 2. Pseudocyclammina sp., N. oolithica, Trocholina sp. In 3. P. aff. lituus (this form is compared by Redmond with his P. sulaiyana).
Age
Depositional setting
Additional Information
The fossil Pseudocyclammina aff. lituus recovered from the lowest unit of the Yamama of Qatar is the form compared with P. sulaiyana by Redmond. R.W. Powers (1968), states that the top of the Sulaiy has been revised upwards in Saudi Arabia, to include the “Yamama Detrital” facies, which contains P. sulaiyana. It is possible that the Sulaiy-Yamama boundary should be revised upwards in Qatar to accommodate this change.
Before sufficient evidence was available to permit correlation of this unit with neighboring developments, its three component members were named, from top to bottom, the Karanah, Qartas and Misfir Formations. These names have now fallen into disuse.