Fig. 3: Plots of the entropy S and mean roughness Ra values of archaeological samples from Hodjiespunt.
From: When was silcrete heat treatment invented in South Africa?
a Plot of 23 known pre- (10) and post-heating (13) surfaces on diagnostic artefacts and their linear best fit (solid lines). The two solid black parallel lines mark the overlap zone in which both pre- and post-heating scars plot. Broken lines and coloured field are taken from the West Coast reference data in Fig. 2a. The lower and upper boundaries of the overlap zone [in Ln(Ra) at the intersection of the fitted function] are 2.12 and 2.16 for the solid lines. Note that both pre- and post-heating surfaces can be distinguished at the two extremities of the scatter plot. b Plot of 52 archaeological test samples onto the reference function and Indet.-zone of a.
