An Increase in Small Flake Sharp-edge Productivity Across the Initial–Early Upper Paleolithic at Tolbor (Mongolia)

Abstract The Upper Paleolithic archaeological record of the Tolbor Valley (northern Mongolia) documents a shift in emphasis from large-blade production to smaller-format bladelet production, characteristic of the Initial Upper Paleolithic (IUP) to Early Upper Paleolithic (EUP) transition in Central and Northeast Asia. This periodization is often associated with, respectively, early dispersal and permanent instalment of Homo sapiens populations in eastern Eurasia. In some regions of West Asia and Europe, an increase in lithic sharp-edge productivity has been described in the EUP, raising the hypothesis that for some groups intensified bladelet production represented a potential solution to constraints on sharp-edge availability. We test this using an allometric approach that controls for blank size, drawing on data excavated from three Upper Paleolithic sites in the Tolbor Valley dated between ca. 45 ka and < 28 ka. A diachronic increase in edge length (~ 10 mm) is detected among small flakes (< 5 g) between the IUP and EUP samples, while laminar blanks (blades/bladelets) show no consistent increase. This suggests that the increased emphasis on bladelet production during the EUP at Tolbor was not primarily a response to constraints on sharp-edge availability. Instead, it coincided with more productive small flakes, whether as byproducts of bladelet manufacture or as a parallel/integrated blank production strategy. These results highlight the importance of accounting for blank size when evaluating diachronic trends in sharp-edge productivity.