From Microcharcoal to Macrocharcoal: Reconstruction of the “Wood Charcoal” Signature in Paleolithic Archaeological Contexts

Abstract

The wood charcoal recovered during archaeological excavations represents only a partial image of the anthracological materials initially produced by human activities. Once buried, these objects are subject to diverse post-depositional processes that fragment them. While macrocharcoals (>500 µm) can be collected one by one and recorded within a coordinate system, or can be extracted by flotation and sieving during excavation, smaller fragments, such as “mesocharcoals” (500-160 µm) and micro charcoals (<160 µm), can be isolated from the sediments only through adapted procedures. A method of extraction and quantification through image analysis has thus been developed in order to record and evaluate the significance of the elements present in the finest sedimentary fractions. Such analyses have been applied in a Paleolithic context at the Magdalenian site of Grand Abri on the coteau de La Garenne (La Garenne hillside) (Saint-Marcel, Indre, France). This work shows that the quantity of charcoal found in the very fine sedimentary fractions (500-160 µm and <160 µm) is greater than that of the macrocharcoals. These quantifications allow us to reconstruct a “charcoal signature” from the macroscopic to the microscopic scale, and thus to identify, in situ, the smallest charcoal fractions resulting from the taphonomic processes that modified the archaeological site.