History Colorado’s early Mesa Verde region collections continue to teach us about ancestral Pueblo people. This summer, these collections drew visiting scholar Theresa Kamper, doctoral candidate at the University of Exeter in the United Kingdom, to Denver in pursuit of her research. Kamper is developing a minimally invasive and inexpensive method of microscopically identifying archaeological tanning processes based on changes in animal skin’s dermal structure when tanned. She has looked at leather artifacts in museum collections in Europe and other parts of the United States. She wanted to include in her research several artifacts from our Wetherill and Wilmarth collections from the Mesa Verde region because of their excellent state of preservation. In fact, she was amazed when she viewed some of the artifacts, noting that several looked like they had been made just a short time ago.
Archaeologists have identified six tanning techniques so far: Wet and Dry Scrape Fat/Adlehyde Tan (brain tan), Alum Tan, Vegetable Tan (bark tan), Urine Tan, and Raw Hide. Kamper explained that by identifying tanning methods, knowing where and when they were used, and observing changes over time, researchers can gain a better understanding of ancestral people's migration patterns, idea transfer, trade, and group identity.
For her project, Kamper prepared skins from 22 animal species from Europe and North America that prehistoric people tanned using each of the above techniques. Since each technique has its unique “signature” that can be seen under the microscope, she can compare archaeological samples to the comparative collection to identify tanning method. Sometimes the tanning process is difficult to determine on artifacts that have been deeply buried, naturally frozen, or exposed to water over long periods of time. Since our artifacts are so well preserved, they can help Kamper better understand how these situations impact identification of the tanning technique.
Kamper analyzed eleven artifacts in our collection made between 600 and 1300 AD. She looked at hide fragments and hide caps and moccasins. Her initial results suggest ancestral people in the Mesa Verde region used the dry scrape brain tanning method most of the time. This method takes a lot of effort. Archaeologists think that the process called for boiled animal brains and water to be mixed to form a paste or liquid. That mixture was applied to skins so the brain oils could soak into skins to produce soft and washable hides. People used skins from a variety of animals such as deer or even rodents.
We are very excited that our collections are helping to develop a technique that archaeologists the world over will be able to use! We look forward to receiving a copy of Kamper’s dissertation when it is complete.
Sheila Goff, NAGPRA Liaison/Assistant Curator, Culture & Community