Late Aptian paleoclimate reconstruction of the Brazilian equatorial margin: inferences from palynology

This study conducted high-resolution paleoclimatic analyses based on the identification of palynological groups of late Aptian age (biozone Sergipea veriverrucata ) in the Bragança and Codó formations within the Bragança–Viseu, São Luís, and Parnaíba basins. The analysis comprised 40 palynological samples, with 200 palynomorphs per slide counted when possible. Bioclimatic analysis was mainly supported by the identification of botanical affinities, and ecological and climatic parameters such as the wet / arid trend ( Fs / X ), Shannon–Wiener diversity, and indicator species analysis (IndVal) were used. Statistical analyses such as principal component and cluster analyses were employed to support the paleoclimatic interpretations. The study recognized 69 genera distributed among the main groups of living plants, including bryophytes, ferns, lycophytes, gymnosperms, and angiosperms. It was possible to attribute botanical affinity in 94.2 % of the taxa, and nine genera occurred in all sections studied: Afropollis , Araucariacites , Callialasporites , Cicatricosisporites , Classopollis , Cyathidites , Deltoidospora , Equisetosporites , and Verrucosisporites , with Classopollis being the most abundant. The stratigraphic distribution of the bioclimatic groups (hydrophytes, hygrophytes, lowland tropical flora, upland flora, and xerophytes) allowed for ...