New paleoenvironmental and palynostratigraphic data from Solimões Formation (Solimões Basin, Amazonas, Brazil)

The Western Amazon was affected by tectonic events of great impacts, such as the uplift of the Andes during the Neogene. Such events promoted significant changes in the fluvial drainage system, in the climate, as well as in the ecosystems, triggering great irradiation of the Amazonian biota. Marine evidence recorded in the region also influenced the radiation of the biota. Despite advances in the paleoenvironmental and age models proposed for the Western Amazon deposits, we still observe conflicting results and interpretations on these aspects. Thus, here were analyzed the palynological content of three cores aimed to contribute with new paleoenvironmental and biostratigraphic data of the Solimões Formation. We presented new paleobotanical data from the 1AS-5-AM, 1AS-7D-AM, and 1AS-8-AM cores and correlated the biostratigraphic data already published with the data obtained here; were recognized five palynozones (Verrutricolporites, Psiladiporites, Crassoretitriletes, Grimsdalea, and Asteraceae), reaching a range from the early to the late Miocene. The vegetation throughout the sequences studied includes elements of dryland forest next to zones of wetlands vegetation, including flooded forests and swamps; the floristic composition changed over time, predominating flooding vegetation during the early and part of the middle Miocene.