Isotopic Evidence for Long-Distance Connections of the AD Thirteenth-Century Promontory Caves Occupants

• Published in: American Antiquity
• Main Authors: Metcalfe, Jessica Z., Ives, John W., Shirazi, Sabrina, Gilmore, Kevin P., Hallson, Jennifer, Brock, Fiona, Clark, Bonnie J., Shapiro, Beth
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2021
• Subjects: Subarctic
• Online Access: http://dx.doi.org/10.1017/aaq.2020.116; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S000273162000116X

The Promontory caves (Utah) and Franktown Cave (Colorado) contain high-fidelity records of short-term occupations by groups with material culture connections to the Subarctic/Northern Plains. This research uses Promontory and Franktown bison dung, hair, hide, and bone collagen to establish local baseline carbon isotopic variability and identify leather from a distant source. The ankle wrap of one Promontory Cave 1 moccasin had a δ 13 C value that indicates a substantial C 4 component to the animal's diet, unlike the C 3 diets inferred from 171 other Promontory and northern Utah bison samples. We draw on a unique combination of multitissue isotopic analysis, carbon isoscapes, ancient DNA (species and sex identification), tissue turnover rates, archaeological contexts, and bison ecology to show that the high δ 13 C value was not likely a result of local plant consumption, bison mobility, or trade. Instead, the bison hide was likely acquired via long-distance travel to/from an area of abundant C 4 grasses far to the south or east. Expansive landscape knowledge gained through long-distance associations would have allowed Promontory caves inhabitants to make well-informed decisions about directions and routes of movement for a territorial shift, which seems to have occurred in the late thirteenth century.