Latest Pliensbachian to Early Toarcian palynological record in the Traras basin (northwestern Algeria)

Abstract

The present study of the Tisseddoura limestones and Bayada bed formations in Traras basin (NW Algeria) refines our understanding of the palynological content of latest Pliensbachian- Early Toarcian interval. The analysis of 38 samples allowed us to identify a diversity of most of the characteristic of palynomporphs such as spores (Rotverrusporites tenuis, Cyathidites australis, Cyathidites minor, Reticulatisporites castellatus, Lycopodiumsporites reticulatum, Lycopodiumsporites clavatoides), pollen grains (Classopollis torosus, Spheripollenites subgranulatus, Callialasporites segmentatus, and Cerebropollenites sp. associated with acritarchs (Micrhystridium sp., Umbellasphaeridium sp., Baltisphaeridium sp., Acanthodiacrodium sp.), and algae (Tasmanites puntatus, Tasmanites sp., Tytthodiscus sp., Leiosphaeridia sp., Crassosphaera sp., Botryococcus sp., Tapajonites sp., unidentified Prasinophytes) unknown in this Algerian basin until now. The results of qualitative and quantitative analyses of pollen assemblages generated new stratigraphic information on the lower limit of Bayada beds and on the impact of the anoxic event on the low presence of spores and pollen grains in the Polymorphum-Levisoni Zones. Finally, this palynological study, carried out for the first time in Algeria, allowed us to identify pteridophyta spores, gymnosperms, acritarchs, and algae that show a great similarity with palynomorphs found in some northern and southern Tethyan basins.