Palynostratigraphy of the Middle Triassic (Anisian) Eslida Formation, SE Iberian Ranges, Spain

The Triassic record in the SE Iberian Ranges starts with two tecto-sedimentary units of continental origin in Buntsandstein facies: and Cañizar and Eslida Formations. The Eslida Formation consists of sandstone bodies intercalated with thick, red siltstone beds. Where this unit is presented, it lies always conformably layers on top of the Cañizar Formation and it grades upwards into overlying coastal mud flats, traditionally assigned to the Röt facies. In the past, accurate dating of the Eslida Formation has been sometimes problematic because of its continental character, absence of datable fossil remains, and lithological similarities with Middle-Upper Permian rocks. Macroflora and fossilised vertebrate footprints in the Eslida Formation indicate an Anisian age (Middle Triassic), in concordance with its stratigraphic position, as both the underlying and overlying units are also Anisian in age. In this work, we date the Eslida Formation on the basis of a palynological assemblage, obtained from a locality near the city of Teruel (SE Iberian Ranges), that includes: Alisporites grauvogeli, Alisporites oppii, Calamospora tener, Concentricisporites neversii, Cyclotriletes oligogranifer, Hexasaccites muelleri, Illinites kosankei, Lunatisporites noviaulensis, Punctatisporites fungosus and Voltziaceaesporites heteromorpha. This palynological association suggests an Anisian age, more precisely a period of time close to the Bithynian-Pelsonian transition. The precise dating of the Eslida Formation is essential in order to establish stratigraphical correlations with other units in the Iberian Ranges and to obtain paleogeographical considerations on the rapid subsidence represented by the sedimentary record of this unit in the new N.NE-S.SE Middle Triassic rift developed in eastern Iberia