Late shellmound occupation in southern Brazil: A multi-proxy study of the Galheta IV archaeological site

Abstract

Brazilian coastal archaeology is renowned for its numerous and large shellmounds (sambaquis), which had been continuously occupied from at least 8000 to 1000 years cal BP. However, changes in their structure and material culture in the late Holocene have led to different hypotheses concerning their ecological and cultural changes. The archaeological site Galheta IV (ca. 1300 to 500 years cal BP) offers new insights into the complexity of the late coastal occupation in southern Brazil. Our attempt was to determine whether Galheta IV can be classified as a sambaqui site, or if it belongs to a Southern proto-Jê settlement. Here, we reassessed Galheta's collections and applied a multi-proxy approach using: new 14C dates, zooarchaeology, δ13C and δ15N isotopes in bulk collagen and 87Sr/86Srenamel isotopic ratios from eight human individuals, ceramics analysis, and FTIR. The results indicate an intense exploitation of marine resources, with an area designated for processing animals located at the opposite side of the funerary areas. Bone tools and specific species of animals were found as burial accompaniments. No evidence of human cremations was detected. 87Sr/86Sr results indicate that the eight human individuals always lived on the coast, and did not come from the inland. The pottery analysis confirms the association with Itararé-Taquara, but contrary to what was assumed by previous studies, the pottery seems related to other coastal sites, and not to the highlands. In light of these findings, we propose that Galheta IV can be considered a funerary mound resulting from long and continuous interactions between shellmound and Southern proto-Jê populations. This study not only enhances our understanding of the late coastal occupation dynamics in southern Brazil but also underscores its importance in reshaping current interpretations of shellmound cultural changes over time.

Fig 1. Location of Galheta IV archaeological site and other settlements of Southern Santa Catarina.

Made with free vector and raster map data. Background: Natural Earth [34]; Digital elevation model: FABDEM V1-2 [35]; Rivers: Brazilian National Water Agency (ANA) [36]. All utilized geographical data are under the Creative Commons Attribution License (CC BY 4.0). Software: QGIS 3.28. Note: Own elaboration.

Fig 2. Excavation grid map of Galheta IV during the “Sambaquis e Paisagem” project.

Including the selected units for zooarchaeological analyses, location of burials and calibrated radiocarbon dates. The burial 2u is the Burial unknown 2, tooth isolated found in fauna samples. Note: Own elaboration.

Fig 3. Calibrated radiocarbon dates for humans’ burials of Galheta IV archaeological site.

In blue the new dates obtained in this study.

Fig 4. Diagnostic bones and teeth used for taxonomic identification, and tools and adornments made from faunal remains.

A: Trachinotus sp. B: Archosargus probatocephalus. C: Genidens barbus D: Hoplias malabricus. E: Thalassarche sp. F: Hydrochoerus hydrochaeris G: Trachemys sp. H: Spheniscus magellanicus I: Arctocephalus australis J: tooth of Carcharodon carcharias polished and drilled twice at the root. K: Elasmobranchii vertebrae perforated. L: Cervidae horn retainer. M: bone tool made of mammal long bone. N: one-sided or two-sided bone tips made from bird and mammal long bones. Note: Own elaboration.

Fig 5. δ¹³C and δ¹⁵N results for Galheta IV humans and fauna samples (n = 38).

Fig 6. δ¹³C and δ¹⁵N results for Galheta IV humans’ bones and dentine samples (n = 18).

Fig 7. Strontium isotopic ratios of humans and fauna enamel samples of Galheta IV (n = 15).

Fig 8. Ceramics from Galheta IV.

A: the reconstructed vessel forms for Galheta IV. B: examples of external surface treatments recorded on the reconstructed forms for Galheta IV. C: the general set of external surface treatments recorded: smudged or with thin dark slip, thin red slip and plastic decoration (from left to right). Note: Own elaboration.

Fig 9. FTIR-ATR spectra of faunal and human bones from Galheta IV, representative of the different colors and heating temperatures.

Fig 10. Geological map of part of southern Santa Catarina coast, with the region of the site Galheta IV magnified on the right corner.

Made with free vector and raster map data. Geological units: Brazilian Geological Survey (SGB) [115]; South America Administrative Boundaries: Brazilian National Water Agency (ANA) [116]. All utilized geographical data are under the Creative Commons Attribution License (CC BY 4.0). Software: QGIS 3.28. Note: Own elaboration.