Credit:
Upper left: Infrared spectrum of the grey sediments, right, showing that the dominant material is calcite, the mineral of which the wood ash is composed. Lower left: Photograph of the cave during excavation; arrow pointing to the hearth. Upper right: Micro-morphological image of the grey sediment showing dark grey particles and patches corresponding to the remains of wood ash. Lower right: Scan of a micro-morphological, thin section showing the layered burnt bones (yellow, brown, and black fragments), intermixed with grey sediments. From the Weizmann Institute of Science.