Strontium isotope movement modeling of modern and ancient megafauna in Alaska

Abstract

Strontium isotope analysis is a technique that can be used to infer the geographic origin of biological materials. The strontium isotope ratios (87Sr/86Sr) of biological tissues can be matched to locations on a modeled strontium geographic distribution (“isoscape”) with similar 87Sr/86Sr. In this dissertation, I measured 87Sr/86Sr and other stable isotopes along the length of a mammoth tusk to model its lifetime movement and infer details about its food sources and nutritional status. I then adapted this modeling method to caribou tooth enamel to compare modern and premodern caribou space use in interior Alaska and built a new 87Sr/86Sr isoscape of interior Alaska and western Yukon with 87Sr/86Sr data from analyses of small rodent teeth. Finally, I added vegetation measurements to the isoscape model in northern Alaska, showing that vascular and non-vascular plants do not differ in 87Sr/86Sr in this region, and argued that further improvement of the isoscape of the region is necessary. Overall, the research completed in this dissertation expanded on the use of 87Sr/86Sr in reconstructing the movement of large mammals, and improved the potential for this proxy to be used in broader provenance and mobility studies in Alaska.