An Upper Pleistocene macroflora indicates warm and dry climate during an interglacial in central Brazil.
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2021
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This study is the first report of the fossil macroflora of the Paleolagoa Seca, an Upper Quaternary fossil locality of
lacustrine origin in central Brazil. Here we present an analysis of well-preserved fossil leaves collected from an
argillite level dated at ca. 43,000 cal yr BP and discuss the paleoclimatic implications of this record. We
reconstructed paleotemperature and paleoprecipitation using Leaf Margin Analysis (LMA) and Leaf Area Analysis
(LAA), respectively, and used mineralogical (XRD and IR) and palynological analyses of the fossiliferous level to
assess a complete picture of the past landscape. To test the ability of LMA and LAA models available for Southern
Hemisphere to correctly predict Mean Annual Temperature (MAT) and Mean Annual Precipitation (MAP) for the
Paleolagoa Seca, we applied several calibration models to the leaf dataset of a modern Cerrado forest and then
compared predictions with modern climate data. Six LMA calibration models presented consistent MAT results
and all four LAA calibration models provided satisfactory estimations of the modern MAP. The botanical iden-
tification of the fossil leaves and the pollen record indicated a mosaic of open savanna, dry forests and gallery
forest around the Paleolagoa Seca. The reconstructed MAP for the Paleolagoa Seca ranged between 647 and
948 mm depending on the LAA equation, which is at least 500 mm lower than the current MAP. The recon-
structed Mean Annual Temperature (MAT) ranged between 22.6 and 26.3 ◦C, indicating a higher-than-present
MAT, which we relate to a combination of high summer insolation and low humidity. Comparison with other
local fossil macrofloras, including from nearby localities, and with other paleoclimatic records suggests that the
observed dry conditions at Paleolagoa Seca were related to interhemispheric climate forcing and to a weakening
of the South American Summer Monsoon (SASM).
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Cerrado, Leaf Margin analysis, Leaf Area analysis, South American summer monsoon, Paleoclimate
Citação
FOLLADOR, G. L. P. P. et al. An Upper Pleistocene macroflora indicates warm and dry climate during an interglacial in central Brazil. Palaeogeography, Palaeoclimatology, Palaeoecology, v. 567, 2021. Disponível em: <https://www.sciencedirect.com/science/article/pii/S0031018221000286>. Acesso em: 29 abr. 2022.