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Vegetation dynamics during the late Pleistocene in the Barreirinhas region, Maranhão State, northeastern Brazil, based on carbon Isotopes in soil organic matter

2004; Cambridge University Press; Volume: 62; Issue: 2 Linguagem: Inglês

10.1016/j.yqres.2004.06.003

1096-0287

Luiz Carlos Ruiz Pessenda, Adauto de Souza Ribeiro, Susy Eli Marques Gouveia, Ramón Aravena, René Boulet, José Albertino Bendassolli,

Amazonian Archaeology and Ethnohistory

The study place is in the Barreirinhas region, Maranhão State, northeastern Brazil. A vegetation transect of 78 km was studied among four vegetation types: Restinga (coastal vegetation), Cerrado (woody savanna), Cerrad"o (dense woody savanna), and Forest, as well as three forested sites around Lagoa do Caçó, located approximately 10 km of the transect. Soil profiles in this transect were sampled for δ 13 C analysis, as well as buried charcoal fragments were used for 14 C dating. The data interpretation indicated that approximately between 15,000 and ∽9000 14 C yr B.P., arboreal vegetation prevailed in the whole transect, probably due to the presence of a humid climate. Approximately between ∽9000 and 4000–3000 14 C yr B.P., there was the expansion of the savanna, probably related to the presence of drier climate. From ∽4000–3000 14 C yr B.P. to the present, the results indicated an increase in the arboreal density in the area, due to the return to a more humid and probably similar climate to the present. The presence of buried charcoal fragments in several soil depths suggested the occurrence of palaeofires during the Holocene. The vegetation dynamic inferred in this study for northeastern Brazil is in agreement with the results obtained in areas of Amazon region, based on pollen analysis of lake sediments and carbon isotope analysis of soil organic matter (SOM), implying than similar climatic conditions have affected these areas during the late Pleistocene until the present.