Microscopic Charcoal Signal in Archaeological Contexts

The recovery of archaeological wood charcoals from combustion features provides insights into the exploitation and use of wood fuel resources and past landscapes. The quality of our interpretation based on wood charcoals, however, depends on reliable information about the charcoal assemblages resulting from taphonomy. Charcoal is very fragile in comparison to other combustion residues such as burnt bones. In archaeological contexts, charcoal can easily be fragmented into small pieces (<0.25 mm) due to their fragile property. The investigation of small fragments and particles is particularly important for the interpretation of combustion residues when large pieces of charcoal are rare or apparently absent in archaeological sites, which is mainly true for many European Palaeolithic sites. Here, archaeologists get incomplete information when only the largest pieces and fragments are considered. In this chapter, we present a method for extracting and quantifying charcoal pieces, fragments, and particles. This approach can be considered as a strategy to minimize the impact of sample incompleteness and biases related to combustion residues in archaeological contexts. We further provide (1) a definition of what the charcoal signal means in an archaeological context; (2) an overview of taphonomy that causes charcoal fragmentation; (3) a review of charcoal sampling, extraction, observation and quantification protocols; (4) a manual (pictures and descriptions) for the observation of charcoal, from large pieces to the smallest particles; and (5) a discussion about why the charcoal signal is useful for archaeologists. By taking into account the consequences of taphonomy, the microscopic charcoal analysis in archaeological contexts provides a reliable assessment of firewood and fuel management practices and the related resilience of societies through time. The microscopic charcoal analysis can further offer additional information about the intensity of taphonomical processes and dating.