Radiation Effects & Defects in Solids Vol. 167, No. 12, December 2012, 947–953 TL dating of pottery fragments from four archaeological sites in Taquari Valley, Brazil Nilo F. Cano a,b *, Neli T.G. Machado c , Roseli F. Gennari a , Rene R. Rocca a , Casimiro S. Munita b and Shigueo Watanabe a a Instituto de Física, Universidade de São Paulo, Rua do Matão,Travessa R, 187, CEP 05508-900, São Paulo, SP, Brazil; b Instituto de Pesquisas Energéticas e Nucleares IPEN-CNEN/SP, Av. Prof. Lineu Prestes 2242, CEP 05508-000, São Paulo, SP, Brazil; c Museu de Ciências Naturais, Centro Universitário UNIVATES, Lajeado, RS, Brazil (Received 26 March 2012; final version received 8 June 2012) Sixty-three pottery fragments from four archaeological sites, numbered RST110, RST101, RST114 and RST114, in the TaquariValley, vicinity of the city of Lajeado, Rio Grande do Sul state, southern Brazil, have been dated by the thermoluminescence method. Some of them from RST110 and RST101 are as old as 1400–1200 years, whereas those from RST114 and RST107 are younger than 800 years. This result indicates that RST101 and RST110 were peopled earlier than RST114 and RST107. The recent dates found are 302, 295 and 146 years and they are possible, since the first German immigrants who arrived in this region encountered Tupi–Guarani Indians still living there. One interesting result refers to the glow curves of quartz grains RST110, RST101 and RST114 that differ from the glow curves of RST107 quartz grains. Keywords: thermoluminescence; dosimetry; ancient pottery; quartz 1. Introduction Schmitz (1) states that the prehistorical study of the Brazilian southern coastal plains is largely based on the so-called sambaqui culture. A sambaqui is a shell mound, to which eating refuses are added and less frequently human skeletons. These sambaquis indicate that the southern sea coast of Brazil was peopled as early as 3340 ± 70 years ago. Guarani and Tupi are two large tribes of natives that initially were separated and occupied northern region of South American Continent. They gradually drifted to the south after giving rise to Tupi-Guarani people by mixing those two tribes, then reaching Bolivia, Paraguay and southern Brazil. Particularly, in this work we are concerned with native Indians in the Rio Grande do Sul State. By radiocarbon dating in the Jacuri riverValley and TaquaniValley, Brochado (2) tentatively established the following time periods for Tupi–Guarani settlement: (a) 500 AD – beginning of the settlement; (b) 500–900 AD – Old period; (c) 900–1300 AD – Intermediate period; (d) 1300–1500 AD – Late period; (e) 1500–1800 AD – Colonial period. *Corresponding author. Email: nilocano@if.usp.br; nfcano@gmail.com ISSN 1042-0150 print/ISSN 1029-4953 online © 2012 Taylor & Francis http://dx.doi.org/10.1080/10420150.2012.702114 http://www.tandfonline.com Downloaded by [USP University of Sao Paulo] at 08:45 03 December 2012