Archaeological and Anthropological Sciences

, Volume 11, Issue 2, pp 713–726 | Cite as

How reliable is the visual identification of heat treatment on silcrete? A quantitative verification with a new method

  • Patrick SchmidtEmail author
Original Paper


Heat treatment of silcrete was a major innovation in the southern African Middle Stone Age (MSA). It allowed for the first time to improve materials for tool knapping, and it may have represented an important step in the perception of natural resources as modifiable objects. Recognising heat treatment in silcrete assemblages is therefore a crucial step for archaeologists working on the MSA. Two different methods, gloss analysis and visual estimation of surface roughness, have so far been used to identify heat treatment. Although both methods have advantages in specific situations, only visual heating proxy classifications allow to count heated vs. not-heated artefacts in assemblages. However, no objective independent data on the reliability and reproducibility of visual classifications are available today. This paper presents a new and promising non-destructive way to measure surface roughness and to verify the reliability of visual classifications: the replica tape method. The results show a rather good reliability of visual classifications: only few pieces are misclassified (n = 3), and the results of both replica tape measurements and visual classification agree within a 3% error range. These results also lay out the foundations for future developments of replica tape measurements to make it a stand-alone method for identifying heat treatment within silcrete assemblages.


Surface roughness Fracture surface analysis Archaeometric technique to identify heat treatment Early-transformative techniques Middle Stone Age archaeology 



I am thankful to John Parkington for providing access to the Diepkloof collections at the University of Cape Town, to Guillaume Porraz for his assistance with pre-selecting and analysing the SU Kerry artefacts and to Pierre-Jean Texier who excavated SU Kerry at Diepkloof. Nóra Sándor helped to elaborate the mathematical pathway for orthogonal projection.

Funding information

Financial support for this study was provided by the Deutsche Forschungsgemeinschaft (DFG) (grant number SCHM 3275/2-1).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2017

Authors and Affiliations

  1. 1.Department of Early Prehistory and Quaternary EcologyEberhard Karls University of TübingenTübingenGermany
  2. 2.Department of Geosciences, Applied MineralogyEberhard Karls University of TübingenTübingenGermany

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