Table 1.
Early Pleistocene, Holocene and PrimArch artefacts examined.
Figure 1.
A three-dimensional model of one of the fine grained igneous experimental hammerstones used in this study.
A) a TIN model of the surface scan of this experimental hammerstone; B) a hillshade model of the same scan as in A, highlighting the percussive damage on the surface of this experimentally made hammerstone. Notice the difference in surface roughness between the left side versus the right side of the scan.
Figure 2.
A schematic representation of the topographic position index.
This shows a schematic description of the TPI index on two identical surfaces with a small window size (A) and large window size (B). The window size changes the resolution of identifying high values (peaks) versus low values (valleys) of the TPI statistic (redrawn from Jenness 2002). C) This is an experimentally damaged percussive tool showing elevation values represented by a TIN model. D) This is the TPI index of the same specimen. Note the edge effects around the borders of the TPI model.
Figure 3.
A schematic representation of the full analysis that identifies the statistically significant (spatially auto-correlated) areas of percussive damage.
The three dimensional nature of this representation prohibits the use of a scale, however this is the specimen that is represented in Figure 2 and as such provides an estimate of the overall size of the damaged area.
Figure 4.
Three-dimensional representations of two polygons identified by the hotspot analysis.
The polygons have been draped over the three-dimensional surface of these specimens. A) Represents a hot spot identified on an experimental hammerstone B) Represents a hot spot on a naturally damaged cobble.
Figure 5.
Box-plot of hotspot polygon perimeter to area ratio values.
Boxes represent the interquartile range of values for the four samples (archaeological specimens from Pleistocene deposits of the KF Fm.; experimental percussive specimens; PrimArch specimens from the KF Fm. (>2.2 Ma); and naturally damaged specimens).
Figure 6.
Box-plot of the ratio of hot spot (peaks) polygon area relative to cold spot (valleys) polygon area.
Boxes represent the interquartile ranges for the four samples (archaeological specimens from Pleistocene deposits of the KF Fm.; experimental percussive specimens; PrimArch specimens from the KF Fm. (>2.2 Ma); and naturally damaged specimens).
Figure 7.
Contrasting spatial autocorrelation analysis (e.g. Hot Spot Getis-Ord*) of an experimentally produced hammerstone (A–B) and a naturally damaged specimen (C–D).
Images A and C represent a hillshade representation micro-topography values.