8th Experimental Archaeology Conference abstract – Stemp and Andruskiewicz

Quantification of surface wear on experimental obsidian blades: First results of the Ancient Maya Blood-letting Project

W. James Stemp (1) & Mason Andruskiewicz (2)

1. Dept. of Sociology/Anthropology, Keene State College, Keene, NH, 03435-3400, United States
2. Surface Metrology Lab, Mechanical Engineering dept., Worcester Polytechnic, Institute, Worcester, MA, United States

It is widely accepted that the ancient Maya practiced sacrificial bloodletting to communicate with their dead ancestors and the gods. Implements to draw blood included a variety of tools, including stone blades made of obsidian. Evidence for blood-letting is based on ethnohistoric accounts provided by the Spaniards, ethnographic observation of modern Maya rituals, iconography depicting bloodletting, hieroglyphic references, and the recovery of artifacts from ritual contexts. However, evidence for blood-letting based on the surface wear on the obsidian blades themselves is inconclusive and difficult to identify. Recent work for quantifying use-wear on stone tools using laser scanning confocal microscopy (LSCM) and scale-sensitive fractal analysis, based on relative area (RelA), has led to an experimental program to quantitatively document wear patterns on replicated stone tools. Three obsidian blade segments were used to cut raw beef as a proxy for blood-letting.

Our results demonstrate that:

  1. Surface roughness can be documented using RelA;
  2. Discrimination of the used from the previously unused surfaces was not always possible; and
  3. the original surface structure of an obsidian blade plays a role in wear formation and subsequent documentation based on RelA.

Stemp, WJ and Awe, JJ (in press) Ritual use of obsidian from Maya caves in Belize: a functional and symbolic analysis. In Obsidian Reflections: Symbolic Dimensions of Obsidian in Mesoamerica, edited by Marc N. Levine and David M. Carballo. University Press of Colorado, Boulder, in press.

Stemp, WJ, Childs, BE, Vionnet, S and Brown, CA (2009) Quantification and discrimination of lithic use-wear: surface profile measurements and length-scale fractal analysis. Archaeometry 51:366-382.

Stemp, WJ and Chung, S (2011) Discrimination of surface wear on obsidian tools using LSCM and RelA: pilot study results. Scanning 33:279-293.

Stemp, WJ, Lerner, HJ and Kristant, EH (2013) Quantifying microwear on experimental Mistassini quartzite scrapers: preliminary results of exploratory research using LSCM and scale-sensitive fractal analysis. Scanning 35, 1: 28-39.

Stemp, WJ and Stemp, M (2001) UBM laser profilometry and lithic use-wear analysis: a variable length scale investigation of surface topography. Journal of Archaeological Science 28:81-88.


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