Phytolith Analysis of Sediments from Early Agricultural Fields at Las Capas, Arizona

Summary

Phytolith analysis of field sediments at the Early Agricultural site of Las Capas document a rich microfossil record of the plant communities that grew in farmed irragric soils and the local environment. Although irrigation water tapped from the Santa Cruz River carried a significant load of naturally derived phytoliths, the signature of cultivated and encouraged plants was clearly recognizable among the diverse identified genera and species. Maize is well-represented, but there is a strong indication of encouraged, if not cultivated, cool-season C3 grasses, likely Hordeum sp. (little barley); this suggests that these grasses were incorporated into the agricultural cycle, perhaps extending seasonal production of the field system. Other identified economically useful plants include sedges, common reed, composites (sunflower family), and bottle gourd. Species from the surrounding natural environment, ranging from the bajada to montane zones, include pine and hackberry. One unusual indicator of the local stream environment is the identification of freshwater sponge spicules and gemmoscleres. These demonstrate that water in the Santa Cruz River flowed consistently and cleanly for extended periods of time in the reach that irrigated Las Capas fields. The phytolith record complements and expands other "conventional" environmental studies such as pollen and macrobotanical analyses.

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This Resource is Part of the Following Collections

• Society for American Archaeology 80th Annual Meeting, San Francisco, CA (2015)   •
• Multidisciplinary Studies of Anthropogenic Change, Subsistence, Social Organization, Regional Interaction, and Technology at the Las Capas Site, BC 1200-400, Southern Arizona

Keywords

Spatial Coverage