Dissertations, Theses, and Capstone Projects

Date of Degree


Document Type


Degree Name





Tom Plummer

Committee Members

Eric Delson

Will Harcourt-Smith

David Braun

Subject Categories

Archaeological Anthropology | Biological and Physical Anthropology | Geochemistry | Geology


Oldowan, tool behavior, raw material sourcing, ED-XRF spectroscopy, hominin evolution, East Africa


The adaptive significance of tool use to genus Homo is a central theme in human origins. However, what we know from the early Oldowan sites suggests that persistent technology may have begun as an opportunistic behavior with minimal investment, rather than a habitual and widespread adaptive revolution. This dissertation seeks to investigate investment in Oldowan tool production on the Homa Peninsula, Kenya, considering raw material selection, transport, and lithic production at two newly discovered Oldowan localities: Nyayanga (ca. 2.6 Ma) and Sare River (ca. 1.7 Ma).

The first section of this dissertation outlines a method that enables the comparison of semi-quantitative elemental values derived from two different Energy Dispersive X-ray Fluorescence (ED-XRF) devices. I demonstrate that values can be compared across datasets if ED-XRF devices are calibrated using five of the same commercially available USGS reference standards and systematic offsets are corrected using simple linear regression equations. The next section of this dissertation uses this comparative method to demonstrate that toolmakers at Nyayanga (2.6 Ma) exhibited similar raw material preferences to later hominins at Kanjera South (2 Ma) and Sare River (1.7 Ma). Toolmakers at all three localities preferentially selected durable materials that link to the same primary sources and Nyayanga hominins traveled up to four kilometers to obtain non-local material. This distance is substantially further than previously documented raw material transport in the early Oldowan. The final section of this dissertation investigates lithic technological production at Nyayanga. Hominins at Nyayanga efficiently removed flakes from cores using unifacial, bifacial, and multifacial reduction comparable to technology at other Oldowan localities. Cores occur frequently in the assemblage and were often used for percussive activities, especially those derived from nonlocal materials. These findings provide new details on variation in early Oldowan technical production and test assumptions about the degree of investment in tool behaviors during the early Oldowan.