Late Albian floras of eastern Iberia: Insights into the palaeoenvironments and palaeoecology of fossil plant communities associated with amber-bearing sedimentary successions

Abstract

Late Albian floras from eastern Iberia are mainly dominated by conifers with xeromorphic adaptations and include well-diversified fern and angiosperm communities. Some of these coniferous taxa are believed to be related to a global mass resin production period known as the Cretaceous Resin Interval (CREI), which ultimately led to the development of amber sites. This research presents a study of late Albian macro- and mesofloras of eastern Iberia from descriptive, palaeoecological, and palaeoclimatological perspectives. The studied material was collected from four outcrops: the Cañada del Hoyo outcrop, located in the Cuenca Basin; and the Arroyo de la Pascueta, Cortes de Arenoso, and San Just outcrops, located in the Maestrazgo Basin. The collected taxa were grouped into four palaeoecological associations (PA-1 to PA-4), representing different biocoenoses from the coastline to the hinterland: Supra-to intertidal vegetal communities (PA-1), Nearshore woodlands with Araucariaceae (PA-2), Drought-adapted hinterland vegetation (PA-3), and Local riparian vegetal communities (PA-4). The dominance of taxa assigned to the genera Frenelopsis, Dammarites, and Eretmophyllum indicates that most of the assemblages are related to supratidal plant communities, a typical feature of the mid-Cretaceous Tethyan coast. Furthermore, we reinforce the hypothesis of an Araucariaceae affinity for some of the upper Albian amber of the Maestrazgo Basin based on the presence of Brachyphyllum cf. obesum Heer (1881) and Rabagostrobus cf. hispanicus Kvaček et al. (2018). We also relate the lack of upper Albian amber-bearing strata in the Cuenca Basin to the sedimentary environment dynamics rather than to the nature of the palaeobotanical assemblages.