Marine Flooding Events of the Early and Middle Ordovician of Oman and the U.A.E. and their Graptolite, Acritarch and Chitinozoan Faunas

Abstract : Graptolites and their associated acritarch floras and chitinozoan faunas are described from three localities in Oman and the United Arab Emirates (UAE). They are characteristic of intervals of deeper water sediments in the Floian ­ Dapingian (Arenig, identified here as maximum flooding surface MFS O25) and mid Darriwilian (Llanvirn, MFS O30). These marine flooding events have distinctive and unique palynological signatures. Most of the recorded Darriwilian fauna and flora have northern Gondwana affinities. Oman and the UAE seem to have occupied relatively elevated positions during the Ordovician and only to have been inundated at times of highest sea level. Exotic rafts of Ordovician Rann and Ayim formations that crop out in the Kub Melange of the Dibba Zone range in age from Floian ­ Dapingian, through Darriwilian, to Katian (Arenig ­ Llanvirn-Caradoc) and may provide a glimpse of a relatively condensed Ordovician stratigraphy that occurs at depth beneath Musandam Peninsula and the Arabian Gulf.