Recent literature on Paleoarchaic and Early Archaic strategies in the arid west of North America has characterized the shift from the earlier to later period as constituting an adaptive discontinuity. The empirical bases for this conclusion are shifts in mobility, subsistence, and technology. Paleoarchaic peoples are described as highly mobile, focused on a diversity of animal resources, including birds and small game, and using more exotic toolstone, an aspect of mobility. In contrast, Early Archaic strategies are less mobile, yet more focused on large game, using more local toolstone, and adopting grinding tools presumably to process small seeds. Accompanying this transition is the shift from stemmed to notched projectile points. Data bearing on this transition on the Colorado Plateau have been scarce. Excavations of finely stratified deposits at North Creek Shelter on the Colorado Plateau in southern Utah have yielded support for the adaptive discontinuity position, although qualitative differences between the Great Basin and Colorado Plateau are apparent in mobility and faunal use.

Early Holocene cultural material at Gerstle River, central Alaska, provides excellent contextual controls for examining variability in radiocarbon dating. Over 4,000 bone and teeth fragments are directly associated with over 7,000 lithic artifacts and 10 discrete charcoal-rich hearths in a thin occupation layer (∼10 cm vertical thickness) within well-stratified loess deposits. Radiocarbon dating of the hearth features indicates overlapping ages at 2σ, suggesting contemporaneity. This study uses the high level of resolution at Gerstle River to evaluate systematic radiocarbon variation due to different materials (collagen and charcoal), different pretreatments of collagen (regular and ultrafiltered), and interlaboratory variation through paired bone and hearth charcoal dates, split samples, and cross-checks. Accurately dating bone collagen is important given the closer association of dated samples with human activities (e.g., butchering) compared with charcoal fragments in certain contexts (e.g., driftwood, paleosols, or alluvial deposits). This study demonstrates the efficacy of bone collagen dating with ultrafiltration to counter potential site-specific contamination. These results also indicate that even in high-resolution situations with little evidence for old-wood effect and contamination, considerable variability can exist among cross-check and even split samples from single pieces of charcoal from short-lived species.

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Small seeds played an important dietary role during the Archaic period in the arid west of North America. The timing of the onset of intensive small seed use is of interest as it suggests a broadening of diets by early peoples and has implications for climatic change. Here we review both direct and indirect evidences of small seed use at critical sites in the Great Basin and Colorado Plateau. This information combined with new data from North Creek Shelter in the Escalante Valley of southern Utah suggests this shift occurred by 9,000 years ago. RESUMENSemillas pequehas eran parte importante de la dieta durante el periodo arcaico en el oeste arido de Norte America. La epoca en la que empezd el uso intenso de semillas pequehas es de interes porque infiere una expansion en la dieta de los primeros habitantes, y tiene implicaciones de cambio climatico. Aqui, examinamos evidencias directas e indirectas del uso de semillas pequehas en sitios importantes del Great Basin y el Colorado Plateau. Esta information junto con datos del North Creek Shelter en el Valle de Escalante del sur de Utah, indica que esta expansion ocurrid hace 9,000 ahos.