UC Santa Barbara

The Arizona Strip and adjacent areas in Utah and Nevada are in a very marginal environment. This dissertation investigates how small-scale farmers who survived more than 1000 years in this area coped with the challenges of this marginal environment by examining how and why social interaction patterns varied over time in different parts of the region.

Artifact assemblages from this area that date between A.D. 200 and 1350 are characterized by widely distributed ceramics tempered with olivine, a volcanic mineral. Sources of olivine lie in the vicinity of Mt. Trumbull and Tuweep, near the northwestern part of the Grand Canyon. The olivine-tempered ceramics were distributed mostly westward from Mt. Trumbull, up to 100 km to the lowland Virgin area in southern Nevada.

Ultimately, the goal of this study is to understand why ceramic production and circulation patterns changed during the Ancestral Pueblo occupation of this peripheral area of the American Southwest. I hypothesize that ceramic production and regional interaction patterns were shaped in part by the need to minimize subsistence risk in this marginal agricultural environment.

To reconstruct ceramic production and consumption pattern, laser-ablation inductively couple plasma mass spectrometry (LA-ICP-MS) was conducted on 1,069 sherds from the Mt. Trumbull/Tuweep and the lowland Virgin areas, along with source clay samples collected from the same areas. To examine how the use of clay resources changed over time, optically stimulated luminescence (OSL) dating was conducted on 113 sherd samples with compositional information.

The data presented here suggest that different environmental conditions favored different social interaction and local ceramic production patterns. In Mt. Trumbull, under unstable climatic conditions and low population density, near the beginning of the Puebloan occupation, pots moved along with human migration. Later, when populations were higher and environmental conditions were equally unstable, pots were moved through interregional trade. In addition, clay resource specialization was favored early but was replaced later by exclusive use of optimal clays when population numbers were higher. In the lowland Virgin area, exchange played an important role as a risk minimization strategy throughout the Puebloan occupation, but clay-resource specialization gained importance later on, when populations increased.