Figure 4
Size distribution and surface alterations of the OMO 79 lithic assemblages. (a) Artifact size distribution of the main lithic assemblages compared with experimental reduction sequences. (b) Microscopic surface alterations of the crystals and ridges on quartz artifacts. (c) Macroscopic surface alterations (details concerning macro- and micro-alterations are provided in Fig. 5). The experimental data used in (a) come from an experimental collection produced by five knappers, four novices and one expert knapper, who reduced a total of 37 quartz pebbles, resulting in 1598 products > 1 cm using a single technique, either bipolar or free-hand, and for the sole purpose of obtaining as many sharp-edged products as possible, until the core was exhausted. Quartz pebbles used for the experiments were collected in the Lower Omo Valley, and selected to be large enough for producing flakes, i.e., > 5 cm in maximum length, regardless their knapping qualities. The experimental dataset is available on Nakala (https://doi.org/10.34847/nkl.3e292r29) and detailed in26,28.
