Archaeoanthrosol formation and evolution of the “Santana do Riacho” archaeological shelter: An old burial site in South America

Abstract

The “Santana do Riacho” shelter is one of the oldest human occupation sites in Brazil. Dated to the Late Pleistocene, this shelter contains over 40 buried individuals. The shelter is located on the edge of the Espinhaço Range in Mesoproterozoic quartzites. This study aims to investigate the relationship between human activities and in situ soil formation. To this end, chemical, physical, X‐ray fluorescence, X‐ray diffraction using synchrotron light, micromorphology, and scanning electron microscope with energy‐dispersive X‐ray spectroscopy analyses were performed. In situ anthropogenic practices, such as fires and burials, have had the greatest influence on the geochemical parameters. Pedological processes were clearly detected, including (1) the formation of secondary carbonates; (2) the formation of secondary phosphates; (3) the formation of magnetic Fe nodules, and (4) degradation of magnetite into maghemite. The mobility of P, Ca, and C resulted in the enrichment of these elements in layers stratigraphically considered “sterile.” The amounts of available P, K, Ca, total organic carbon, and the pH values can be considered indicators of human occupation. This study provides information on the pedological processes in rockshelters and represents one of the few pedological and geochemical studies on deposits in a tropical rockshelter in quartzite bedrock.

Linking anthropogenic burning activities to magnetic susceptibility: Studies at Brazilian archaeological sites

“…These data lead to >75% SP grains (J. Dearing, 1999) and indicate the presence of magnetite in anthropogenic hearths, as early demonstrated by de Sousa et al (2017). At Lapa do Malhador, during the Holocene (8500 14 C year B.P.…”

“…At Santana do Riacho, the large fires accompanied burial ceremonies (layer SR2, Table 2) (P. Junqueira & Prous, 1991). Most likely, these fires had a long duration, leading to high MS and fine SP grains, such as magnetite and maghemite, as demonstrated by de Sousa et al (2017) through X‐ray diffraction (XRD) analysis. The Lapa do Boquete, in the Peruaçu valley, shows an intense human occupation throughout the stratigraphy.…”

“… c Santana do Riacho site was dated by Prous et al (1991), and calibrated dates were taken from Sousa et al (2017). …”

“…To minimize this issue, we adopted the soil science survey method for the collection of samples (Lemos et al, 2015; Schoeneberger et al, 2012). Beach (1998), Wagner and McAvoy (2004), Ahr et al (2013), and de Sousa et al (2017) also adopted this approach in pedoarchaeological research. This sampling strategy ensures that the analytical result applies to the entire horizon/layer and is not a specific location value or a single variation.…”

Making the Invisible Stratigraphy Visible: A Grid-Based, Multi-Proxy Geoarchaeological Study of Umhlatuzana Rockshelter, South Africa

“…These values seem to be high when compared to pH analyses conducted on sandstone rockshelters globally. Some examples outside of South Africa include: Gledswood shelter 1 (Australia), which reports pH ranging from 5 to 5.5 (Lowe et al, 2018), Nonda Rock rockshelter (Australia) with pH ranging from 4.5 to 5.5 (David et al, 2007), Loberia I rockshelter (Argentina) where pH ranges from 3.7 to 5.8 (Martínez et al, 2013), and Santana do Riacho rockshelter (Brazil) with a pH from 4.4 to 6.4 (de Sousa et al, 2017). In comparison, Umhlatuzana displays quite high variation in pH values (4.…”