Heat treated or not heat treated: Archaeological and experimental interpretation of flint assemblage from the Middle Pre-Pottery Neolithic B site of Yiftahel

Recent examination of the lithic assemblage from the Middle Pre-Pottery Neolithic B (MPPNB, 10,100–9,250 BP cal.) layers of Yiftahel in the Lower Galilee, Israel, revealed a relatively large number of flint artifacts showing evidence of intentional heating. Heat treatment of siliceous raw materials is a worldwide phenomenon usually used during the initial stages of a chaîne opértoire for the improvement of the blank detachment process. Nevertheless, visual observations of the assemblage from Yiftahel supplemented by Fourier transform infrared spectroscopy (FTIR) tests show that heat treatment was carried out during the later stages of reduction sequence, mainly on blade blanks, before their transformation into tools. Careful and intentional annealing of this type of blank probably allowed better control over the heat treatment process and more successful propagation of pressure retouch during the final stages of tool modification. In some cases, heat treatment also affected the color of the item, perhaps increasing its visual attractiveness. The smooth and aesthetic appearance of pressure retouch on the one hand and the appearance of “eye-catching colors” of the blanks on the other, perhaps increased the economic value of finished tools and influenced their spread within local exchange trade networks and perhaps beyond.