Revisiting palaeolithic combustion features of Theopetra Cave: A diachronic use of dung and peat as fuel

The chemical diagenesis and palaeoenvironmental reconstruction of the Palaeolithic sequence of Theopetra Cave have been studied extensively, but little information is available regarding the details of its combustion structures. The cave is characterized by extensive beds of multi-sequence combustion layers dated between 140 and 50 ka BP, and thick, often stratigraphically complex bodies of ash and charred remains dated between 16 and 13 ka BP. All combustion features contain large amounts of charred and partially charred fibrous organic matter of non-wood plant material and very little charcoal. The structure, fabric, composition, and chemistry of these remains suggest that a mixture of peat and dung was used as a fuel, occasionally enriched with amounts of wood fuel. The integrity of the sequence of combustion structures precludes the possibility that dung was produced by animals inside the cave as their traffic on its wet substrate would have destroyed the burnt layers and homogenized the sediment. The mixture of peat and dung was most likely collected from peatlands associated with swamps of the former so called Karditsa Lake that probably existed in the area until the beginning of the Holocene. Peat and dung were used as a fuel when wood fuel was not available, during the relatively cold intervals of the glacial periods, but also during the last interglacial when the area close to the cave was wooded. Of great interest is that this same fuel was used during both the Middle and the Upper Palaeolithic, presumably by different human species. Although Theopetra appears to be the first site that peat and dung was used as a fuel during the Middle Palaeolithic, it is suggested that other sites may have used this fuel as well. This has important consequences in understanding the evolution of human pyrotechnology particularly during glacial periods.