A Holocene vegetational and climatic record from the Atlantic rainforest belt of coastal State of São Paulo, SE Brazil

Abstract

Holocene vegetation and climate have been reconstructed by means of pollen analysis in a 643-cm-long core from the Jacareı́ peat deposits (23°17′S, 45°58′W, 550 m a.s.l.) within the Atlantic tropical rainforest belt in the State of São Paulo, SE Brazil. Three conventional 14C dates indicate that the onset of peat formation started at 9720 years BP. Due to sampling restrictions, the record encompasses the period between 9720 and ca. 1950 years BP. The palynological content of the samples permitted the recognition of five distinct climatic periods between 9700 and ca. 1950 years BP: humid and cool climate from 9720 to ca. 8240 years BP, humid and warm from ca. 8240 to ca. 3500 years BP, cooler and moister than today from 3500 to 1950 years BP. The return of a cool climate at the late Holocene is suggested by the reappearance of montane and humid forest taxa such as Araucaria, Drimys, Daphnopsis, Ericaceae, Podocarpus and Myrsine in the upper sections of the pollen diagram. Throughout its formation, the Jacarei peatbog has had a very different botanical composition. Gleichenia was the most important taxon in the peat bog from 9720 to 8240 years BP, followed by Selaginella, Polypodium and Asplenium until 5400 years BP. A Sphagnum/ Lycopodium dominated peat was established from 5400 to 3500 years BP, followed by Gleichenia/ Sphagnum from 3500 to ca. 1950 years BP. The interpretation of the pollen and spore diagrams permitted a correlation between the vegetational and climatic signal contained in the Jacareı́ peatbog with other locations in southeastern and southern Brazil.