Developing REE parameters for soil and sediment profile analysis to identify Neolithic anthropogenic signatures at Serpis Valley (Spain)

In this study, patterns of rare earth elements (REE) have been developed and applied for the first time to sediments and soils to identify anthropogenic or natural layers in profiles sampled at several Neolithic settlements in the Serpis Valley area (Alicante, Spain). Most of these sites are characterized by dark brown paleosols that are easily distinguishable from the light brown paleosols of the valley. To demonstrate whether these strata are anthropogenic or natura requires a better geochemical understanding of sediment. Soil samples were taken across six different sites; four sites are associated with archaeological findings (sites BF, LP, PB and AC8); another one is from a natural section from Mas D’Is (MD) located close to the archaeological site in which evidence of human occupation from the Neolithic period has been found; and the last corresponds to a place of uncertain attribution (BK5), where no archaeological remains have been found, but where layers of a recent agricultural activity are present. REE results comprising REE ratios, cerium and europium anomalies, and La/Yb-Sm/Eu correlations were compared with major and minor chemical components, mineralogical properties of the soil layers and, when it was possible, cross-referenced with archaeological data to aid interpretation. The results demonstrate the potential of REE data to distinguish strata associated with Neolithic occupation from those that have not been subjected to anthropogenic modification.