Triassic sporomorph data for the Umm Irna Formation: Age constraints from the northwestern part of Jordan

The Umm Irna Formation, covering a large area in Jordan, shows lithological variations from one area to another. The previous palynological works assigned a Permian age to this rock unit. The current palynological analysis was achieved on twenty samples taken from the claystone and shale interbeds of the Umm Irna Formation. Most of the selected samples were barren. Some longranging taxa with high thermal maturity were recorded. In addition, a black to brownish Triassic sporomorph assemblage was extracted in the present study from a few productive samples from the coarse- clastic dominated Umm Irna section exposed in the northwestern part of Jordan. A poorly diverse assemblage, including 39 sporomorph species, was identified. This contribution gives palynological evidence of the Triassic age for the Umm Irna Formation, based on the qualitative and quantitative control of the marker taxa Endosporites papillatus, Alisporites magnus, Falcisporites stabilis, Cyclotriletes microgranifer, and Cycadopites follicularis. The plant affinity of the recovered sporomorph taxa was noted. For better correlation across the Tethyan Realm, the stratigraphic distribution ranges of some selected diagnostic palynomorph species in Jordan and other Tethyan sites were compared. The current assemblage represents significant sporomorph data for the Umm Irna Formation and proves its age to be not older than the Triassic.