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Dr. Rhy McMillan

I/S Core team member, Rhy McMillan, successfully defended his PhD on February 27. Congratulations Rhy!  Here is a summary of his thesis:

Detailed written records only exist for a very small amount of human history. Researchers must therefore combine Indigenous traditional knowledge with scientific evidence, often collected with geochemical and spectroscopic techniques, to investigate ancient human biology, behaviour, and culture. However, acquiring meaningful scientific information about rare and culturally-sensitive materials without destroying or modifying them is extremely challenging. The four research chapters in this dissertation adapt and develop analytical frameworks for appropriately acquiring key data from archaeological biominerals and mineraloids to address the fundamental question:

‘What was the original context and condition of the archaeological materials we find?’

The first two research chapters focus on investigating the post-mortem histories and diagenetic alteration of archaeological bone using our novel ‘Perio-spot’ technique. In Chapter 2, we evaluate the depositional histories, stratigraphic provenance, and thus age of megafauna and Neandertal bones at Scladina Cave (Belgium). In Chapter 3, we assess the taphonomic state of archaeological bones and the effectiveness of acetic acid pre-treatment procedure used to remove diagenetic alteration, documenting that it may actually concentrate post-mortem signals in recrystallized, intensively-altered bones.

The last two research chapters focus on enhancing the traditional techniques for sourcing obsidian (volcanic glass) stone tools in the Pacific Northwest. Our step-wise ‘Splitting Obsidian’ approach (Chapter 4) involves non-destructively investigating all artifacts in an assemblage for elemental concentrations and structural characteristics, then analyzing a subset of representative artifacts for lead (Pb) isotope compositions and more precise trace element concentrations using minimally-invasive techniques. In Chapter 5, we apply this approach to a suite of rare archaeological belongings in partnership with xʷməθkʷəy̓əm (Musqueam), an Indigenous community near Vancouver (Canada), and suggest ancient transport of obsidian over distances exceeding 1000 km in western North America. This supports the oral history and continuity of intricate xʷməθkʷəy̓əm social and material networks, providing additional key lines of evidence for how and from where people procured resources in ancient North America.

In summary, the contributions made in this dissertation research provide unique and robust scientific techniques and data that support investigations of ancient human history while minimizing the destruction and alteration of valuable archaeological materials and contexts. Some fo this work has been published:     

McMillan, R., Weis, D., Amini, M., & Bonjean, D. (2017). Identifying the reworking and stratigraphic provenance of bones by exploring multivariate geochemical relationships with the “Perio-spot” technique. Journal of Archaeological Science88, 1–13.

McMillan, R., Snoeck, C., de Winter, N. J., Claeys, P., & Weis, D. (2019a). Evaluating the impact of acetic acid chemical pre-treatment on ‘old’ and cremated bone with the ‘Perio-spot’ technique and ‘Perios-endos’ profiles. Palaeogeography, Palaeoclimatology, Palaeoecology 530, 330-344.

McMillan, R., Amini, M., Weis, D. (2019b). Splitting Obsidian: Assessing a multiproxy approach for sourcing obsidian artifacts in British Columbia. Journal of Archaeological Science: Reports 28, 102040.

And Rhy and his co-authors won the American Geophysical Union's Outstanding Student Presentation Award for Chapter 5:

McMillan, R., Weis, D., Amini, M., & Rathbone, A. (2019c). Identifying Long-Distance Transport of Obsidian Across the North American Landscape in Antiquity Based on Indigenous-led Research Initiatives. American Geophysical Union Fall Meeting 2019. (