The present study reveals palaeoenvironmental changes in the coastal southern Brazilian highlands during the last 39720 B.P., by the means of pollen, charcoal and multivariate data analyses. The isolated mountain range

Paleoenvironmental interpretation of proxy data derived from peatlands is largely based upon an evolutionary model for ombrotrophic bogs, in which peat accumulates in still environments. Reports on proxies obtained from minerotrophic fens, where hydrologic inputs are variable, are less common. In this study, a highland peatland in southern Brazil is presented through ground penetrating radar (GPR) and sedimentological, palynological and geochronologic data. The radar stratigraphic interpretation suggests a relatively complex history of erosion and deposition at the site since the beginning of Marine Isotope Stage 3 (MIS 3) interstadial period. In spite of this, radar stratigraphic and palynologic interpretations converge. Electromagnetic reflections tend to group in clusters that show lateral coherence and correlate with different sediment types, while pollen grains abound and are well preserved. As a result, the study of minerotrophic fens provides a source of proxies, suggesting that ombrotrophic bogs are not the only reliable source of data in wetlands for palynological analysis.

No abstract

A high-resolution pollen record of the Atlantic rain forest (ARF) biome from the coastal Serra do Tabuleiro mountains of southern Brazil documents an 11,960 yr history of vegetation and climate change. A marked expansion of Weinmannia into the grassland vegetation marks the latter part of the Younger Dryas, reflecting warm and relatively wet conditions. Between 11,490 and 9110 cal yr BP, grasslands became dominant again, indicating a long cold and dry phase, probably in response to the stronger influence of cold South Atlantic seawater and to Antarctic cold fronts. Between 9110 and 2640 cal yr BP, four distinct phases with strong or moderate expansions of different ARF biome taxa were recorded, reflecting warmer and relatively dry conditions with changes in rainfall and length of the annual dry season. After 2640 cal yr BP, the modern ARF biome became established with high amounts of ferns, reflecting somewhat cooler and wetter conditions with a reduced annual dry season. In particular, after 1000 cal yr BP tree ferns increased, reflecting wetter conditions with no dry season.