Radiocarbon, Vol 56, Nr 2, 2014, p 489–499 DOI: 10.2458/56.16954 © 2014 by the Arizona Board of Regents on behalf of the University of Arizona Proceedings of the Radiocarbon and Archaeology 7th International Symposium Ghent, Belgium, April 2013 | Edited by Mark Van Strydonck, Philippe Crombé, and Guy De Mulder © 2014 by the Arizona Board of Regents on behalf of the University of Arizona CHRONOLOGICAL MODEL OF A BRAZILIAN HOLOCENE SHELLMOUND (SAMBAQUI DA TARIOBA, RIO DE JANEIRO, BRAZIL) K D Macario 1,7 • R C C L Souza 2 • D C Trindade 3 • J Decco 3 • T A Lima 4 • O A Aguilera 5 • A N Marques 5 • E Q Alves 1 • F M Oliveira 1 • I S Chanca 1 • C Carvalho 6 • R M Anjos 1 • F C Pamplona 5 • E P Silva 2 ABSTRACT. Since the beginning of the Holocene, hunter-gatherers have occupied the central-south Brazilian coast, as it was a very productive estuarine environment. Living as fshers and mollusk gatherers, they built prehistoric shellmounds, known as sambaqui, up to 30 m high, which can still be found today from the Espírito Santo (21°S) to Rio Grande do Sul (32°S) states, constituting an important testimony of paleodiversity and Brazilian prehistory. The chronology of the Sambaqui da Tarioba, situated in Rio das Ostras, Rio de Janeiro, is discussed herein. Selected well-preserved shells of Iphigenia brasiliana and charcoal from freplaces in sequential layers were used for radiocarbon dating analysis. Based on a statistical model developed using OxCal software, the results indicate that the settlement occupation begun most probably around 3800 cal BP and lasted for up to 5 centuries. INTRODUCTION In the central-south Brazilian coast, the Holocene faunal assemblage, sea-level changes (Suguio et al. 1985, 1991; Angulo and Lessa 1997; Angulo et al. 1999, 2006, 2007; Dias 2009; Dias et al. 2009), and long-term oscillation of coastal upwelling intensity (Carbonel 1998; Castelao and Barth 2006; Mahiques et al. 2010) are closely related to the human occupation. Therefore, archaeological information provides an alternative data set that allows to better understand the past, building a baseline for time-depth climatic and environmental interpretation, and shedding light on the impact of modern civilization on the environment (Lotze et al. 2006). Therefore, this study on the early human settlement, the pristine environment, and the biodiversity patterns for a given locality in the Brazilian coast will be informed by a radiocarbon data set for evaluating the time-depth occupation and environmental changes in the Holocene. The best in situ testimonies for prehistoric chronology research in the Brazilian coast are the archae- ological sites known as shellmounds (sambaquis). They are prehistoric mounds of discarded edible mollusks. It is now well established that the Sambaquis are not only archaeological funerary places but also habitation settlements, with evidence of diverse activities (food processing, artifacts manu- facturing, habitation structures). Most Brazilian shellmounds date from 6000 to 2000 cal BP (Prous 1992; Gaspar 1996; Lima 1999/2000; Wagner et al. 2011), with a few dates up to 9000 cal BP (Lima et al. 2002). These shellmounds were mainly studied under the scope of archaeological re- search (e.g. Von Ihering 1903; Gliesch 1930; Fróes de Abreu 1932; Leonardos 1938). The early 1. Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, Niterói, 24210-346 RJ, Brazil. 2. Laboratório de Genética Marinha e Evolução, Instituto de Biologia, Depto. de Biologia Marinha, Universidade Federal Fluminense, Outeiro São João Batista, s/n, Niterói, 24001-970 RJ, Brazil. 3. Instituto Brasileiro de Pesquisas Arqueológicas, Rua Marques de Leão, 53 Engenho Novo, 20780-140, Rio de Janeiro, 20785-060 RJ, Brazil. 4. Departamento de Antropologia, Museu Nacional Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, São Cristóvão, Rio de Janeiro, 20940-40 RJ, Brazil. 5. Departamento de Biologia Marinha, Instituto de Biologia, Outeiro São João Batista, s/n, Universidade Federal Fluminense, Niterói, 24001-970 RJ, Brazil. 6. Departamento de Geoquímica, Instituto de Química, Outeiro São João Batista, s/n, Universidade Federal Fluminense, Niterói, 24001-970 RJ, Brazil 7. Corresponding author. Email: kitamacario@gmail.com.