MODELS OF LANDFORM CLASSIFICATION TO UNDERSTAND ARCHAEOLOGICAL SITE DISTRIBUTION IN DUNE LANDSCAPES OF NORTHERN ARIZONA

Located on the southern edge of the Tusayan Dune Field in northeastern Arizona, Petrified Forest National Park contains abundant archaeology sites located in dune settings. Past and recent archaeological survey has shown an apparent correlation between archaeological site locations and eroded dune blowouts. It is likely that sites are located in dune settings due to their favorable environmental setting. However, it is not clear if the apparent distribution of visible sites in relation to eroded dunes is meaningful, nor is it clear if distribution patterns relate most closely to cultural behaviors of deposition, or are more closely tied to exposure through post-depositional dune movement. This study uses spatial analysis of dune landscapes in several study areas to better understand the formation processes of archaeological sites in these dune environments.

This study explores relationship between archaeological site location and geomorphic landforms in order to determine whether there is a significant correlation between site location and areas with dunes or dune blowouts. Due to the great variability in the terrain, with greater relief among rock outcrops and mesas, and only low relief among dunes, classifying the landscape into dune forms and dune blowouts from a DEM using traditional landform classification methods does not work. A simplified topographic position index (TPI) constructed in ArcGIS works to classify the landscape into dunes, dune blowouts, and flat areas using a 10m resolution DEM. However, this model is limited by low resolution DEMs in the study area, and by the uncertainties of classifying the low relief areas. Statistical analyses show that there is a non-random distribution of sites on dune landforms, with sites preferentially located within dunes.

Archaeological data and statistical analyses are used to explore whether geomorphic patterning is due to behavioral processes or due to natural processes of erosion and deposition. It is likely that archaeological site location within dunes is due to favorable characteristics of dunes as habitation settings. This is a first step in understanding the site formation processes, site distribution, and site visibility in eolian settings in Petrified Forest National Park.