Interview with Bioarchaeologist Dr. Andrew Nelson
MOA had the opportunity to sit down with Dr. Andrew Nelson, an Associate Professor in Anthropology at Western University, to discuss some of his more recent work, including his contribution to the Art Gallery of Ontario’s Small Wonders exhibition, which includes a Virtual Reality Medieval Prayer Bead, now available at MOA.
Andrew’s research interest are focused in two major subfields of anthropology: biological anthropology and archaeology. When he is not scanning artifacts in Sustainable Archaeology or working on the many research projects at Western University, Andrew can be found navigating the complexities of archaeological sites both local and abroad.
How is the MicroCT scanner important in better understanding archaeological material?
The microCT scanner allows non-destructive analysis of the composition and method of construction of archaeological materials. For instance, with ceramics, one can understand the choice of tempers, the means of construction of a vessel (slab, coil etc) and how the clay was prepared (the distribution of particles throughout the clay). The key elements are the non-destructive nature of the analysis and the three dimensionality of the information that is provided.
Tell us about your research on the MicroCT Scanner in Sustainable Archaeology: Western
Most of my work has been exploratory, answering questions such as how can the scanner be used to aid in the analysis of both bones and artifacts from archaeological excavations. Some examples:
– scanning the earliest coins that have value backed by the state – Lydian coins – to address the question of how they were made. They are made of a gold and silver alloy – electrum – which is just about the best thing to completely stop x-rays there is. Fortunately, our scanner has very high power and we were able to establish that they were made from molten gold and silver added together – rather than from heated nuggets – because we can see through the scan that there are small bubbles in the metal.
– I am interested to use the microstructure and density of different kinds of wood to identify wood species used in archaeological artifacts. This is an ongoing effort that arose from the prayer bead work, and continues with some work I am just beginning with the conservation program at Queens on Egyptian coffin wood samples.
– I have also been working with external researchers exploring the use of the microCT scanner in other realms, such as the analysis of meteorites, copper/steel simulators of the lining of nuclear containment vessels, the deformation of human shoulder joints, examination of metal 3D prints, concrete samples etc. The possibilities are truly endless – but many of them feed back to things we’re trying to do in archaeology – such as the meteorties and concrete samples having many similarities to the examination of archaeological ceramics.
The themes here are non-destructive and 3 dimensional. In addition several of these examples draw on one of the particular strengths of this microCT system – its considerable power, enabling us to penetrate very dense objects. Something that is extremely important to emphasize about this work is that it is inherently interdisciplinary and collaborative… I spend a lot of time working with imaging physicists, radiologists, chemists, geologists, bioengineers to name only a few.
“That is one of the most exciting aspects of working with the scanner – everyone brings a different problem to solve, a different perspective on how to solve problems – so there is always a buzz during plans for and actual scanning sessions.”
Even though we have had the scanner for several years now, we’re still finding new ways to use it, new ways to optimize what we have been doing, exploring new analytical routines to use on our artifacts and new people we need to talk to. And there is lots yet to explore.
You mention your work with the boxwood prayer beads. What did the MicroCT scanner unveil about the manufacture of these beads?
This analysis allowed us to see the unseen – the complex nature of the construction of these amazing beads. Once scanned, I was able to “deconstruct” the beads in the computer, demonstrating that they were composed of a complex series of elements, which were then assembled such that it was impossible to see seams from the front. In this case, the bead was all made from the same material (box wood), but the three dimensionality and the ability to manipulate the data virtually were the keys to understanding the bead’s construction. The results led to a greater appreciation for the sophistication and craftsmanship of these medieval artisans.