A Lower Cretaceous palynoflora from Carregueira (Lusitanian Basin, westernmost Iberia): taxonomic, stratigraphic and palaeoenvironmental implications

Here we describe a new Lower Cretaceous palynoflora from the Lusitanian Basin, located in the westernmost sector of the Iberian Peninsula. The spore-pollen assemblage was extracted from samples collected in the Carregueira clay pit complex, located near the village of Juncal, western Portugal, from sedimentary deposits belonging to the Figueira da Foz Formation. A rich and well-preserved palynoflora, typical of non-marine fluvial environments, was recovered. Fifty-eight species and morphological groups of palynomorphs in 43 genera were recognized. The palynoflora is dominated by fern spores and conifer pollen. Angiosperm pollen is scarce and mainly represented by Afropollis, Clavatipollenites, Stellatopollis and Senectotetradites. Comparisons with described marine sections in Portugal suggest that the fossil horizon is lower Albian, corresponding to a hiatus between Zone I and Zone II in the Potomac Group of the eastern USA. The same beds contain a mesofossil flora dominated by angiosperm seeds, fruits and flowers. A similar contrast in the relative abundance of angiosperm mesofossils and pollen is seen at other Portuguese localities but is not evident in the Potomac Group. The palynoflora and the sedimentological data suggest deposition in wet lowland environments in a moderately humid regional setting.
This research was supported by grants from the Amadeu Dias Foundation, the Portuguese Science Foundation (FCT) through the project UIDB/04292/2020 to MARE - Marine and Environmental Sciences Centre, the Czech Grant Agency (project 20-06134S) and by the Swedish Research Council (VR, grant no. 2019-4061).