Analysis of stratigraphical sequences at Cocina Cave (Spain) using rare earth elements geochemistry

Abstract

This study investigates the stratigraphical sequence of Cocina Cave (Spain) employing and testing for the first time the capability of rare earth elements as markers of human activities in caves. Located in Dos Aguas (Valencian Community, Spain), Cocina Cave is characterized by the presence of several Holocene archaeological deposits from the final Mesolithic to the present day and is a pivotal site for understanding the socio-ecological dynamics of the last hunter-gatherer inhabitants of the Iberian Peninsula and the transition to pastoral and agricultural economies in the Western Mediterranean. However, the identification of strata from particular time-periods in the cave is often difficult due to the homogeneity of layers, the poor archaeological record in some strata and the presence of severe disturbance phenomena. The methodological approach of this study consisted of crossreferencing rare earth elements and other chemical markers with the archaeological stratigraphical interpretation, in an attempt to not only support the identification of the anthropic contribution to the formation of Cocina Cave strata, but also to characterize and confirm different natural and occupational episodes, particularly those associated with hunter-gatherer, early agriculturalist, and shepherd activities. Sediments were collected from different excavation areas and analysed for major elements, trace elements, rare earth elements (REE), soil organic matter (SOM) amounts and pH. Multivariate statistics were employed to group samples according to their elemental profile, and these were then compared to the archaeological temporal interpretation. The obtained results showed that REE amount and fractionation geochemical processes were regulated by carbonates, phosphates and pH. The use of REE as markers was particularly useful as their concentrations and their calculated ratios and anomaly distributions were demonstrated to be highly consistent with the archaeological stratigraphical interpretation.

Rare earth elements sediment analysis tracing anthropogenic activities in the stratigraphic sequence of Alagankulam (India)

“…Equally, our data obtained in Cocina Cave (Spain) [ 18 , 19 ] showed that REE geochemistry was controlled by carbonate and phosphate phases in an alkaline environment, while REE fractionation marked the difference between Mesolithic, Neolithic and Bronze Age layers.…”

“…Therefore, following the research aim, the digestion method consisted of aqua regia . Further details on acid digestions can be found in a previous work published by Gallello and colleagues [ 18 ].…”

“…Ce or Eu anomalies higher than 1 indicate positive anomalies, close to 1 (±0.1) an absence of anomalies, and values < 1 negative anomalies. More details can be found in Gallello and colleagues published studies [ 16 , 18 ].…”

“…Recently the potential of rare earth elements have been explored for the identification of anthropogenic and natural deposits in archaeological contexts [ [13] , [14] , [15] , [16] , [17] , [18] , [19] ]. The promising data produced during these last years of research have shown the complexity of REE soil geochemistry and at the same time the role of REE for clarifying different archaeological issues.…”

Rare earth elements in aeolian loess sediments from Menyuan Basin, northeastern Tibetan plateau: Implications for provenance

“…frontiersin.org proxies to reveal the source, genesis, and sedimentary environment (Jiang et al, 2019;Gallello et al, 2021;Romero et al, 2021;Zhang X et al, 2021;Deng et al, 2022a).…”