The Ras Al Hamra Limestone: An Outcrop Analogue to the Shallow Cores of Umm Er Radhuma Formation?

An outcrop in the Ras Al Hamra area and two nearby shallow cores were studied. The main focus of the project is the description of lithofacies, identification of paleofauna and -flora, the regional distribution and the correlation between surface and subsurface facies.

The limestone is of Paleocene-Eocene age covering a part of the Arabian Plate Megasequence AP 10. The microfossils observed in the outcrop and cores indicate a Late Paleocene/Early Eocene age. the time-equivalent facies of the outcrop is Jafnayn Formation and the sub-surface equivalent is the Umm Er Radhuma Formation.

The main lithofacies types identified are foraminifera and dasycladacean wackestone deposited in an inner platform low energy environment and larger benthic foraminifera (LBF) grainstone and packstone and coral boundstone from a medium to higher energy environment.

In terms of diagenesis it has been witnessed that the Ras Al Hamra carbonates have undergone physical compaction, chemical compaction (pressure solution), dissolution and cementation. This has influenced the porosity in which most of the primary porosity was destroyed by cementation.

Similar facies can be observed in both the outcrop and the cores examined, however due to diagenetic processes it is concluded that the Ras Al Hamra outcrop is not a good analogue to the subsurface.