Four Corners Phase Sequence
Below is a basic introduction to the archaeological and cultural history of the Four Corners region presented in the Pecos Classification phase sequence. Click on the hyperlinks in blue for more information.
| Phase Sequence | Time Period | Archaeological and Cultural Summary |
| Paleo-Indian Period | 10,000 – 5,500 BC | Small bands of hunters relying on large, now extinct, Pleistocene megafauna. Three complexes based on time sequence: Clovis, Folsom, Plano |
| Archaic Period | 5,500 BC – 1,200 BC | Extinction of earlier Pleistocene fauna; small hunting and gathering groups; widespread use of wild plant resources |
| Early Basketmaker II | 1,200 BC – 50 AD | Lived in the open or in caves; nomadic lifestyle but first cultivation of maize |
| Late Basketmaker II | 50 – 500 AD | First successful agricultural populations; sedentary settlement pattern; shallow pit structures; extensive storage features |
| Basketmaker III | 500 – 750 AD | Widespread adoption of domesticated crops: maize, squash, and beans; pithouses, pottery, and introduction of bow-and-arrow. |
| Pueblo I | 750 – 900 AD | Increase in number of sites and average site size, the appearance of above-ground jacal and stone architecture alongside semi-subterranean pithouse structures, and larger storage facilities. So-called “proto-kivas” first make their appearance |
| Pueblo II | 900 – 1,150 AD | Further increase in the number of sites and site size, a shift toward above-ground coursed masonry architecture, larger numbers and larger sizes of storage facilities, and formal kivas. Sites typically contain between 6 and 9 rooms, with increasingly complex architecture, multistory construction; Chaco phenomenon flourishes |
| Pueblo III | 1,150 – 1,350 AD | Aggregation of populations into progressively larger centers, gradual collapse of the Chaco phenomenon; realignment of social structures toward Mesa Verde and Aztec; dramatically reduced rainfall; site abandonment toward end of the period |
| Pueblo IV | 1,350 – 1,600 AD | Significant movement of people into river valleys for more reliable water, especially along the Rio Grande, Rio San Jose, and Zuni River. Most sites are small, but some of the largest contain over 500 rooms. |
| Pueblo V | 1,600 – Present | Post European contact |