Among Land Snail Shells and Ashes: Geoarchaeological Analysis of the Maximiano Rockshelter, Southeast Brazil

Abstract

Geoarchaeological studies, particularly those incorporating micromorphology and associated techniques, have revealed the complex depositional and post-depositional history of mollusk shell-matrix archaeological sites, mostly in coastal areas where these sites are more widespread. But geoarchaeology can also be crucial to disentangle human and natural agencies in inland shell-rich settings, including caves and rock-shelters. In this paper, the site formation processes of the land snail-rich Maximiano Rockshelter, located in the karstic upper Ribeira de Iguape River valley of southern São Paulo state, Southeast of Brazil, are tackled. Embedded in the neotropical Atlantic Forest, the site contains lithics, bone artifacts, and faunal and human remains dating between ~11,165 and 1282 cal year B.P. Facies and microfacies were characterized in exposed stratigraphic profiles through micromorphology, particle size analysis, major, minor, and trace elements, and FTIR spectroscopy. Despite the strong humification affecting most of the site, results indicate deposits resulting from anthropic activities such as the dumping of land snail shells and other remains, the tossing of entire and fragmented shells in sub-horizontally distributed layers, primary combustion features, and dumping/sweeping of combustion-derived materials. Shell-bearing facies exhibit similarities with chronologically contemporaneous Ribeira de Iguape basin's riverine sambaquis.