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Osman Abdelghany, United Arab Emirates University (United Arab Emirates)
Mohamed Boukhary, Ain Shams University (Egypt)
Yasmine Hussein-Kamel, Ain Shams University (Egypt)
Salah Bahr, Ain Shams University (Egypt)
Mousheera Abdelraouf, UAE Univ. (United Arab Emirates)
AbdulRazak Alsayigh, Qaboos Univ. (United Arab Emirates)
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An Early Oligocene (Rupelian) diagnostic larger foraminiferal assemblage is described and illustrated from marls and limestones of the Asmari Formation, at Jabals Hafit and Malaqet in the United Arab Emirates. An equivalent assemblage is identified in the mudstones of the Tahwah Formation, Wadi Suq, Sultanate of Oman. The assemblage comprises Nummulites intermedius D'Archiac, 1850; N. fichteli MICHELOTTI, 1841 (Early Oliogcene of SCHAUB, 1981). The presence of Blondeauina bouillei (BOUKHARY, ABDELGHANY and HUSSEIN-KAMEL) n.gen., N. fabianii hafitensis BOUKHARY, ABDELGHANY and HUSSEIN-KAMEL n.ssp., N. intermedius, Planoperculina complanata, Austrotrillina asmariensis Adams, 1968 and N. fichteli within the same horizon confirms an Early-Middle Oligocene age for the Asmari Formation. Although Nummulites intermedius has been considered to be synonymous with Nummulites fichteli, in this study the two species are biometrically differentiated, distinct and both names are valid. N.fichteli, N.intermedius and N.fabianii hafitensis are index for the Early Oligocene (Rupelian) and they progressively replaced each other competitively and environmentally.
The studied marls and limestones were deposited in outer and inner shelf environments, respectively. The Asmari Formation in the area studied consists mainly of marl in its lower portion and reefal limestone in its upper part, indicating a major marine regression. The Tahwah Formation in Oman is composed of bioturbated silty and muddy marls. It is a slope deposit, based on the occurrence of planktonic foraminifera, larger foraminifera and corals in debris flows, and is a facies equivalent of the Asmari Formation marls. The Asmari Formation facies change probably relates to a mid-Oligocene fall in global sea level. The study intends also to use the subsurface information of the Oligocene Dabaa Formation which produced from five wells, Western Desert, Egypt, to correlate this sequence with that in United Arab Emirates and Sultanate of Oman. Key words: Oligocene, Asmari Formation, Tahwah Formation, Dabaa Formation, larger foraminifera.
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