Palynological trends and sedimentological framework of a Barremian estuarine and barrier-island system in the western Tethys (Camarillas Formation, eastern Spain)

Abstract The Early Cretaceous Camarillas Formation represents a thick and extensive estuarine and barrier island-lagoonal depositional system that developed in the Western Tethys (Iberian Basin, eastern Spain). Thirty-seven percent (7 out of 19) of the palynological samples collected from three stratigraphic sections of this formation (six from the sedimentary stage 2 and one from the stage 3) were productive, containing well-preserved palynological assemblages, including 105 taxa. Despite having similar facies to the productive ones, the remaining 63% of the samples were barren of palynomorphs, suggesting that environmental conditions, rather than taphonomical bias, played a key role in preservation. In general, gymnosperm pollen grains and fern spores dominate the palynoflora. Scarce angiosperm pollen grains and aquatic palynomorphs also occur. The most representative taxon in the studied levels is Classopollis obidosensis . Angiosperm pollen predominates in the uppermost productive level, whereas the Cyathidites / Deltoidospora spore-type abounds in a basal one . The palynological study confirms a Barremian age for the Camarillas Formation and provides insights into vegetation mosaics that included conifer-forests along the western Tethyan coasts. However, the data suggest a palaeofloristic change throughout the succession. Firstly (Stage 2), it is characterized by the alternation between xerophytic conifer-woodlands that developed in arid and/or coastal areas and freshwater swamps containing taxodioids and ferns. Then (Stage 3), gymnosperm-producers of the pollen type Cycadopites / Monosulcites and pioneer angiosperms inhabited brackish swamps.