Shifting stones and changing homes: using toolstone ratios to consider relative occupation span in the northwestern Great Basin

Like Paleoindian populations elsewhere in North America, Pre-Archaic groups in the Great Basin are assumed to have been highly mobile and far ranging. This view is commonly based on analyses of lithic technology and source provenance studies. While these approaches have added to our knowledge of Pre-Archaic lifeways, they have rarely focused on occupation span – an aspect of hunter–gatherer behavior directly related to mobility. Here, I use the proportions of local and nonlocal toolstone in Pre-Archaic and later Archaic assemblages to consider occupation span with the assumption that assemblages should become increasingly dominated by local materials as occupation span increases. The results suggest that residential mobility was high and occupations short before 7500 radiocarbon years ago. Conversely, between 7500 and 1300 radiocarbon years ago, residential mobility decreased and many locations were occupied for extended periods. Occupation span once again decreased as residential mobility increased after 1300 radiocarbon years ago. These trends were likely influenced by changes in the environmental and demographic climate of the Holocene.