Archaic-Age Architecture in Northwest Colorado

Abstract

Archaic-era hunter-gatherers in the Wyoming Basin—which extends across southwest Wyoming and northwest Colorado—built domed or conical architectural features, with some exhibiting far more substantial construction than others. These structures are often archaeologically preserved as large elliptical basins, defined by charcoal-stained sediment that filled habitation footprints after abandonment. Many of these basins, or house pits, are probably residential remains, although some may have had other uses. The recent discovery of 32 house pits in Colorado’s Yampa Valley in the Sand Wash Basin has expanded the regional dataset, increasing our understanding of Archaic-era lifeways in northwestern Colorado. These discoveries further demonstrate the highly variable nature of Archaic-era structures, reflecting the adaptability of a mobile lifestyle to a specific place and time. Archaic-era use of these features in northwest Colorado occurred between about 8100 and 3755 cal B.P., demonstrating the usefulness of such shelters across a wide range of climate regimes. The greatest numbers were built between 6800 and 6000 cal B.P., coinciding with the mid-Holocene thermal maximum, when the residential settlement pattern grew more restricted, centering on water, food, and shelter resources. As the warm, arid climate ameliorated after 5500 cal B.P., use of such shelters began to decrease, demonstrating a return to higher residential mobility with greater availability of resources in the cooler, wetter climate. A comparison of Yampa Valley house pits with northern Wyoming Basin house pits indicates that Archaic-era people utilized similar structures as part of a highly adaptable mobile lifestyle for thousands of years across the Wyoming Basin.