Upper Jurassic palynology from the Blue Nile Basin (Ethiopia)

Abstract

Late Jurassic paleobotanical records from the northeast of Gondwana are rare. We present the first palynological assemblage from the upper part of the Antalo Limestone Formation from the Blue Nile Basin (central western Ethiopia). A diverse and well-preserved assemblage of palynomorphs with 70 morphospecies belonging to 39 morphogenera, including pollen, spores, fungi, algae, dinoflagellates cysts and foraminifera test linings are recorded. The First Appearance Datums (FADs) and Last Appearance Datums (LADs) of key taxa such as Cicatricosisporites spp., Pilosisporites trichopapillosus (Thiergart) Delcourt and Sprumont, 1955, Leptolepidites psarosus Norris, 1969, Cibotiumspora jurienensis (Balme) Filatoff 1975 and Callialasporites turbatus (Balme) Schulz, 1967 are indicative of an age between Late Kimmeridgian and Late Tithonian. The recorded palynological association is dominated by palynomorphs of continental origin (mostly pollen and spores). Prasinophyceae, dinoflagellate cysts and foraminiferal test linings have also been recorded that suggest marine influence within a setting very close to the continental landmass. The botanical affinities and environmental characteristics of the identified pollen and spores indicate the presence of three types of continental plant communities (sporomorph ecogroups): coastal plant communities with a dry climate and lowland and riverbank communities signaling a more humid and warm climate.