Spatial analysis of the isotopic signal (δ13C) of palaeolithic charcoal: A suitable tool in chrono-environmental contextualisation of Points Cave (Gard, France)

Abstract

Wood taxonomic analyses are a useful tool for reconstructing local woody environments. Typically, the palaeoecological relevance of anthracological remains is assessed through the examination of numerous wood charcoal fragments scattered in sediments, which reflect relatively long periods of occupation. Sampling is conducted through sieving or flotation to minimize collection bias, followed by interpretation based on the frequency spectrum of the taxa. However, when applied to Palaeolithic sequences, the limited taxonomic diversity, coupled with occasionally poor preservation of the charcoal, may restrict the interpretations of conventional anthracological approaches. Furthermore, certain chrono-stratigraphic contexts and the potential loss of material during sampling can complicate these studies.

In this article, we propose an alternative and complementary approach for studying charcoal from Points Cave (Upper Palaeolithic, Gard, France). Manual collection of charcoal, with recording of spatial coordinates, was supplemented by systematic sediment sieving. A combined taxonomic and isotopic analysis (δ¹³C) was then applied to the entire corpus. Spatial restitution of the data was subsequently performed.

This original approach enabled us to identify several distinct “isotopic sets”, defining multiple phases of successive occupation under varying climatic and environmental conditions. These chrono-environmental data allowed the targeting of additional radiocarbon dates, which validated this division. While a purely taxonomic analysis would have provided a general overview of forest composition over an extended chronological period, the combination of an adapted protocol and a multiproxy charcoal analysis allowed for an expanded discussion on a finer chronological scale.