Looking for a Long-Term Record in the Greater Yellowstone Ecosystem: The 2010 Field Season at The Stinking Springs Rockshelter, Teton County, Wyoming.

Abstract

The mountainous environment of northwestern Wyoming is not known for the preservation of organic remains, specifically that of vertebrate species. The paucity of vertebrate remains has hampered the ability of researchers to understand the evolution of the Quaternary mammalian community, which is in sharp contrast to the detailed understanding of the region’s geologic, climatic, and vegetation history. The few sites that have produced vertebrate remains have been largely confined to dry caves and rockshelters in the surrounding region and a few open air archaeological sites. In southern Teton County we have located a large rockshelter at the mouth of Hoback Canyon that presents a unique opportunity to recover a long-term mammalian record documenting Quaternary paleoecological change. Hand augering in 2006 revealed evidence of intact, datable strata likely to yield a robust mammalian faunal record. A radiocarbon age of 4210 ± 50 yrs BP was obtained from Ponderosa pine charcoal at a depth of 90 cm below surface, suggesting a record extending at least to the mid-Holocene. In 2010, the Utah State University Field School conducted limited controlled excavations in two 1m2 units. Excavations produced additional evidence of stratified deposits to a depth of 1.9 m. Remains recovered include lithic debitage, hearth features, faunal remains, and a possible large mammal processing area. Two specimens, one on Pinus charcoal from a depth of 1.9 m and a portion of a bighorn sheep mandible from 1.0 m, were submitted for radiocarbon assay. The ages are 4350 ± 25 yrs BP and 3360 ± 25 yrs BP, respectively. The size, geology, and setting above the Hoback River in a natural bottleneck between ungulate winter and summer ranges make the Stinking Springs rockshelter an excellent candidate for archaeological and paleoecological investigation. Proposed future investigations are designed to assess the rockshelter for the presence of preserved vertebrate remains and the deposit’s potential to address a number of key issues of how the mammalian community developed during the Quaternary in relation to large-scale (e.g., glaciation) and small-scale climatic (e.g., post-glacial maximum warmth, Little Ice Age) shifts. The anticipated record will not only provide information on the mammalian community structure, but will also provide a paleoecological model for understanding the economies of precontact Native American groups who lived in the region, and will also provide key information that can be applied to future management of threatened species and their habitat (e.g., pronghorn antelope).