Inferring Early Stone Age tool technology and raw material from cut mark micromorphology using high-resolution 3-D scanning with applications to Middle Bed II, Olduvai Gorge, Tanzania
Date
2018
Authors
Keevil, Trevor L., author
Pante, Michael C., advisor
Glantz, Mica, committee member
Lacy, Michael, committee member
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Abstract
The appearance of cut marked bones in the archaeological record 2.6 million years ago roughly coincides with the emergence of simple Oldowan core and flake tools in the East African archaeological record. This development is associated with the dietary shift in Early Stone Age hominins to carnivory and numerous morphological changes in the genus Homo, including larger brain sizes. Approximately 1.7 million years ago, Homo erectus, a new species of hominin, emerges alongside a technological transition in the East African archaeological record from the simple core and flake technology of the Oldowan to the more advanced bifacially flaked large cutting tools of the Acheulean tradition. However, the function of these Acheulean handaxes remains uncertain. To fully appreciate the relationship between evolutionary changes in the hominin lineage and the development of different stone tool traditions, experimental models capable of identifying how different tool forms were used by early hominins when butchering large mammal carcasses must be established. Previous macromorphological studies of bone surface modifications have shown that cut marks on bones can be accurately differentiated from tooth, trample, and rodent gnaw marks. However, studies relating cut mark micromorphology to the specific technological form or raw material type of the tool that made the mark have been limited due to poorly defined analytical methodologies that use subjective and qualitative observations to describe mark morphology. The lack of a standardized approach for diagnosing tool technology from cut mark morphology has limited the development of models capable of effectively interpreting the dynamic butchery and lithic behaviors of Early Stone Age hominins during the Oldowan-Acheulean transition. This thesis presents an objective and replicable approach for quantitatively modeling micromorphological characteristics of experimentally created cut marks to examine whether different stone tool types leave unique and quantifiable patterns in the cut marks they create. Experimental cut marks were created using Oldowan flake tools and Acheulean biface tools. Both tool types were made from four different raw material types commonly found in Early Stone Age archaeological assemblages from Olduvai Gorge, Tanzania: quartzite, basalt, chert, and phonolite. Experimental marks were scanned using a Nanovea white-light confocal profilometer and analyzed using Digital Surf's Mountains Software to generate multivariate discriminant models capable of categorizing cut marks based on the form of the tool that created them. These models were used to classify the tool forms that created 1.6 million year old archaeological trace marks recovered from a site in Middle Bed II, Olduvai Gorge, Tanzania. The results from this thesis indicate that when the morphological features of a cut mark are analyzed and modeled using high-resolution 3-D scanning, the Early Stone Age tool technology and raw material type that made the mark can be accurately identified. Identifying the causal connections between cut mark morphology and properties of the stone tool that created the mark has important applications for further understanding the evolutionary trends in morphology, behavior and cognition of Early Stone Age hominins.
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Subject
cut marks
micromorphology
Early Stone Age
archaeology