A new age to an old site: the earliest Tupiguarani settlement in Rio de Janeiro State?

This paper presents unexpectedly early dates for a Tupiguarani settlement in Southeastern Brazil. One radiocarbon dating of 1740 +/- 90 yr BP (1820-1390 cal yr BP) was already available for the Morro Grande site (Araruama, southeastern coast of Rio de Janeiro State). Two new dates, obtained from charcoal samples, are reported here. An age of 2920 +/- 70 yr BP (3220-2790 cal yr BP) was obtained from a specialized hearth, probably used for cooking ceramics; a funerary hearth at the same archaeological locus was dated at 2600 +/- 160 yr BP (3000-2150 cal yr BP). Both measurements were made independently, indifferent laboratories, arguing for their validity. These results considerably age the arrival time of Tupiguarani populations to the coastal region of Southeastern Brazil. They may have important implications to the hypotheses about the origin and dispersion of these populations from Amazonia, supporting the claim of recent authors who consider that their expansion must have begun well before 2000 yrs BP.