Stone-Tool Workshops of the Hatrurim Basin, Israel: Mineralogy, Geochemistry, and Rock Mechanics of Lithic Industrial Materials

Unique stone-tool factories have been recognized in the Hatrurim Basin, at one of the largest localities of combustion metamorphic rocks of the Hatrurim Complex (Israel and Jordan). Larnite-rich rocks formed along the western side of the Dead Sea Transform Fault in Israel by combustion of hydrocarbon gas at temperatures between 975-1000 °C and 1300-1380 °C, and baking of hydrothermally altered chalky-marly rocks of the sedimentary sequence. These larnite-rich rocks were favored by hominids to produce stone axes and adzes. Abundant supplies of extremely dense, hard larnite-rich rocks and numerous stone-tool workshops in this part of the Hatrurim Basin suggest production on an industrial scale. The main mineral species of the bifacial tools are larnite, ye'elimite, gehlenite, brownmillerite, fluorapatite, fluorellestadite, rankinite, kyuygenite, and silicocarnotite. For the larnite-rich stone tools, we determined densities between 3.09 and 3.26 g/cm³ and elastic moduli between 100 and 145 GPa, which makes these rocks the densest and strongest rocks in the Levant. We are surprised by the skillfulness and intelligence of hominids who managed to use such tough material for stone-tool production. Recognizing similar axes and adzes in stone-tool collections around the world will unambiguously indicate their source from the Hatrurim Basin, and may clarify whether the bifacial tools are Paleolithic or Neolithic.