Characterization of soil profile developed in a riverine shellmound (Sambaqui Moraes), Miracatu-SP, Brasil

Abstract

Archaeological excavations carried out in the riverine shellmound Moraes, Miracatu, SP - Brazil, pointed out distinct archaeological layers which resulted in the mound configuration of the site. Therefore, aiming at reaching a first approach on the formation process of the site, physical-chemical soil analysis from inside and outside the site were developed in order to comprehend the properties that could have contributed for the characterization of the peculiarities found on the archaeological layers of this riverine shellmound.

It was demonstrated a large alteration in many chemical and physical properties of the soil horizons developed in the shellmound. The high levels of phosphorus in the dark horizons indicate an enrichment of that horizon by addition of residues rich in this element (e.g. bones). The dark horizons also show high levels of organic carbon in comparison with the original soil horizon. However, if the stabilization of the organic carbon that allows its accumulation in the dark horizons of shellmonds is because formation of stable compound with calcium and/or effect of heating (pyrogenic carbon) it is not clear and should be further investigated.