Sequence stratigraphy, biostratigraphy and paleontology of the Maastrichtian-paleocene Aruma Formation in outcrop in Saudi Arabia

Abstract

The Aruma Formation is a predominantly carbonate lithostratigraphic unit of Late Cretaceous age that crops out in Saudi Arabia. It consists of three members: from base to top they are Khanasir Limestone Member, Hajajah Limestone Member, and Lina Shale Member. In order to establish a stratigraphic revision of the Formation, a reference section near Al Kharj, southeast of Riyadh in central Saudi Arabia, was logged and a hierarchical organization of the depositional sequences established. The Aruma corresponds to four third-order cycles bounded by erosional unconformities. Integrated biostratigraphical data mainly based on ammonites, nannoflora, rudists, and larger foraminifera point to a Maastrichtian age for the Khanasir and Hajajah members, and a Paleocene age for the Lina Member. Regional stratigraphic correlations were established within the outcropping Aruma Formation in Saudi Arabia. Biostratigraphy and sequence stratigraphy allowed a correlation framework to be proposed between the Aruma and the Qahlah and Simsima formations of the United Arab Emirates and the Oman Mountains, and with the Sharwayn Formation of the Hadramawt and Dhofar. The high-resolution stratigraphic scheme established for the Aruma Formation in Saudi Arabia is expected to be useful for subsurface correlations and in petroleum exploration.