Os povos caçadores e coletores que habitaram as margens da Lagoa Mirim

Abstract

In the last four decades, archaeological research (synthesized in Oliveira et al. 2003; Oliveira and Teixeira, 2005a,b; Oliveira 2006) points out that the main precolonial inhabitants of the southern coastal plains of Brazil, in the region of Santa Vitória do Palmar and Chuí, was the constructors of earth mounds, locally known as cerritos, of the Vieira tradition. However, the archaeological sites recorded by the “Banco de Dados Arqueológicos e Paleontológicos do Litoral Sudeste do Rio Grande do Sul, Brasil (BDAP)”, according to Oliveira (2006) shows that there would have been another types of sites, associated to different populations and distinctive chronological moments, such as eroded sites over sand dunes (located in the coastal zone) and slope sites, located in the fringes of Lagoa Mangueira marshes. Besides of them, there are also sites that are, until now, poor known and no research have been made until now, wich are the focus of this study. The sites, located along the oriental margin of the Lagoa Mirim, are composed basically by flaked lithic material with significant presence of projectile points. The region, as a whole, is characterized (Villwock and Tomazelli, 1995) as a large coastal plain where grasslands, marshes, lagoons and moist areas conform the dominant landscape. In Santa Vitória do Palmar, the fringes of the Lagoa Mirim occupy all the extension of its territory up to Rio Grande (at North) as far as the Uruguai border (at South). Given the stablished chronologies by various authors (such as Schmitz et al., 1991; Mentz Ribeiro, 1999 and Consens, 2004 among others) to the inicial occupation of the Southern Brazil and northern Uruguai by hunters and gatherers with projectile poits, we believe that the occupation of the lithic sites in the oriental fringes of the Lagoa Mirim takes place between 10.000 to 6.000 years B. P., at the end of an intensive marine regression that reached its height at about 18/17.000 years B. P., in wich the Patos-Mirim lagune system changed into a large aluvial plain, where rivers such as Jaguarão, Cebolatti, Taquari among others run over ancients marine-lagune deposits, forming small valleys (Villwock and Tomazzelli, 1995). This groups would have stablished in the terraces of the paleovalleys that converged to the northeast of the present lake, before to drain at the Atlantic Ocean, through the present Banhado do Taim. These groups, possibly derived of the valley of Rio Negro region, have found in that place suitable conditions to develop their way of life. As from the holocenic transgressive height, at about 5.000 years B. P., the valleys are again drowned and starts a new cycle of formation of the Mirim paleolake, until it be isolated, forming the lake as we know today. From now on, a new cycle of human occupation also develops, with the cerrito builders in the marsh areas along creeks and streams, in the terraces of the newly formed Lagoa Mangueira and in the sand dune fields of the atlantic coast.