Architecture of Maastrichtian carbonate deposits of the United Arab Emirates and Oman Sultanate border region

This paper discusses the sedimentary model, sequence framework and geometry quantification of sedimentary bodies in an Upper Cretaceous carbonate platform, abounding in oil reservoirs, The outcrops are located along the western margin of the northern Oman Mountains in the border region of the United Arab Emirates and the Sultanate of Oman. The Maastrichtian Simsima Formation outcrops on several N-S-trending jebels, situated between the localities of Al Dhaid and Al Ain. Jebel Rawdah was studied in detail, whereas Jebel Faiyah is documented as another reference section for correlation purposes. A sedimentary reconstruction of the latest Campanian - Late Maastrichtian interval displays a gradual change from tidal flat and foreshore to outer platform settings. This evolution shows the flooding of the study area after Late Campanian times. Two third-order sequences were identified on the Maastrichtian intra-platform ramps. Both of them can be subdivided into a complex arrangement of 4(th) and 5(th) order sequences. Third-order sequences exhibit composite features and contain aggradational/retrogradational and progradational trends. A direct relationship was identified between the sequence framework and the palaeoecological distribution of reel builder and free organisms. The former developed essentially in retrogradational trends whereas the benthic foraminifera Loftusia commonly appears in platform flooding intervals, and orbitoids mainly occur within progradational trends. Widespread sedimentary tectonic activity is documented in the palaeogeographic reconstruction of the Simsima Formation. Several palaeohighs and grabens, related to the general foreland basin context of the UAE platform, are recognised in the Jebel Rawdah. Finally, the sequence framework of the Simsima Formation in the Jebel Faiyah is similar to that of the Jebel Rawdah and makes it possible to propose an accurate sequence framework correlation.