Blanks with a thickness, measured at the thickest part of the blank (the bulb of percussion excluded), of no more than 3mm, did not fracture in a spontaneous microburin (Figure 11).
To the contrary, the bulb of percussion was removed and the residual piquant triedre delivered a sharp pointed scar, already known from Krukowski microburins.
Eventually, this repeated failure inspired knappers to start retouching below the bulb of percussion and then move upwards to the heel of the blank.
During initial manufacture, the flake blank's edges were removed up to the margins of the bulb of percussion either by freehand percussion or percussion using anvil support.
It was observed during these replication experiments that each successive flake seemed to have a somewhat more convex bulb of percussion than the flake preceding it.
This data suggests that the gull wing method of core reduction enhanced the prominence of the bulb of percussion, supporting the emphasis placed on this feature by Roth (1904: 17).
A gouge-shaped, or U-shaped, edge profile is an outcome of retouching a distal edge onto a pronounced bulb of percussion (e.
In most stone technologies worldwide, the bulb of percussion on flakes was an inevitable and not particularly important aspect of flake selection.
Indigenous Australian knappers were unique in focusing on the bulb of percussion itself in designing a stone woodworking tool.