Perspectives on food and movement: shellmounds occupation in the southern and southeastern Brazil through multiple isotopic proxies

Soutenance de thèse de Jéssica Mendes Cardoso.

Committee Members:
Mme Klervia JAOUEN (GET/OMP/CNRS) – Directrice de thèse
M. Andre STRAUSS (MAE/USP) – Directeur de thèse
Mme Daniela KLOKLER –  Examinatrice
M. Murilo BASTOS – Rapporteur
M. Jeroen SONKE – Examinateur
M. Michael RICHARDS – Rapporteur 

Abstract:
Brazilian sambaquis are an outstanding testimony to the dense pre-colonial human populations in South America, spanning millennia. Dating back at least 10,000 years for riverine shellmounds and 8,000 to 1,000 years for coastal ones, these communities are believed to be descended from the migratory wave that reached South America around 16,000 years ago. In the coastal regions shifts in coastal site construction occurred around 2,000 years ago, including the transition from shellmound settlements to fishmound ones. In this thesis, we employed a multiproxy isotopic approach to analyze seven Brazilian archaeological sites, encompassing both shellmounds and fishmounds, located in Santa Catarina (Capivari I, Cabeçuda, Jabuticabeira II, and Galheta IV) and São Paulo (Moraes, Piaçaguera, and Tenório). Our objective was to enhance our understanding of the diet and mobility patterns of these populations. To achieve this, we conducted analyses of both fauna and human skeletal remains, generating over 900 new isotopic results, including 14C, δ13C, δ15N, δ13CAA, 87Sr/86Sr and δ66Zn. Trace elements ratios were added to identify the presence or absence of diagenesis. A new Bayesian mixing model was employed, including both traditional and non-traditional isotopic proxies, in order to access diet proportions in different food sources. Through this thesis, it becomes evident that intra and inter-regional variabilities are recurrent. Different shellmounds exhibit distinct dietary habits. Mollusks could have been a daily food source for the populations of sambaquis, especially at Capivari I, Moraes, and Piaçaguera. However, these proportions appear low in other sites, such as Cabeçuda. In southern Santa Catarina, fishing played a major role, representing the highest proportions of their diets. In São Paulo all sites demonstrated a high diversity of food sources consumption, with the coastal sites relying on both marine and terrestrial environments. At Moraes, we identified two distinct groups of individuals who resided in separate geographical areas during their childhood and adolescence. While low mobility was evident in coastal shellmound sites, movements across the coast cannot be disregarded. In both regions, fishmound sites exhibited greater population heterogeneity, irrespective of the presence or absence of ceramics. The movement of people from the hinterland to the coast at the late Holocene was not overwhelming, and the evidences does not point out a replacement of populations. Moreover, the non-local individuals found on fishmounds were mainly women and children. Shellmound culture should not be perceived as a simplistic and/or static cultural entity across time and regions. We highlight numerous differences in dietary habits, emphasizing the dynamic nature of shellmound societies.