Archaeological anthrosols of the lower Uruguay river: a geoarchaeological approach to the formation processes of the Isla de Vizcaíno 1 archaeological site (Río Negro department – Uruguay)

Abstract

This work presents the results of the analysis of archaeological anthropogenic soils analysis of Isla de Vizcaíno 1 site (Río Negro Department, Uruguay), located on a riverbank and dated around 1500 years BP. Through a comparative measurement design (inside and outside the site), we sought to characterize the modifications generated by pre-Hispanic human populations that inhabited these environments, in terms of their role as a pedogenetic agent, and at the same time provide data that, with a solid basis, allow discussing the formation processes of elevated sites from the littoral region.
The results achieved through granulometric, compositional and geochemical analyzes showed clear differences between archaeological anthropogenic soils and adjacent natural soils, evidenced mainly by the presence of cultural material and higher organic matter and phosphorous content in the first. From generated data, the presence of two horizons of a metagenetic anthrosol (HAM) were identified, that is, a soil composed of altered material (and not transported) by human agency, characterized as quartz-feldspathic anthrosand. This alteration of the soil, linked to domestic and ritual activities in this site, highlighted the role of pre-Hispanic inhabitants as a pedogenetic agent and as an active actor in landscape modelling and environmental engineering.