Formation processes and combustion features at the lower layers of the middle palaeolithic open-air site of nesher ramla, Israel

The lower stratigraphic sequence (units III-VI) of the Middle Palaeolithic site of Nesher Ramla was studied using geoarchaeological methods. Field observations indicate that the site formed within a karst depression that was infilled by colluvium and in which intermittent human activity occurred, including two layers highly rich in anthropogenic remains (units III and V). Infrared analysis of bones determined that black bones are carbonized and that certain white bones are calcined. Quantitative analysis of wood ash pseudomorphs indicates specific areas of high concentrations of ash. Micromorphological analysis enabled identification of two distinct features associated with ash and burnt bones. One is a thinly bedded complex of blacked soil overlain by ash and charcoal, and the second is a ~20cm thick massive, fine-grained layer of mixed ash. The first feature is interpreted as an in situ hearth. Macroscopically similar features have not yet been analyzed. The second feature is interpreted as ash in secondary position, i.e., an ash pile/midden that formed following hearth rake-out activities. These findings are unique considering that most Middle Palaeolithic open-air sites in the Levant are single-layered, and that in most evidence for hominin use of fire is scarce or absent. We discuss the factors that may affect the preservation of ash in open-air sites, and conclude that the setting of Nesher Ramla in a topographic low provided relative protection from wind which prevented ash deflation, and at the same time, hominin activity remains were buried relatively fast which detached the ashes and combustion features from direct rainfall and from decalcifying root activity.