Los Pozos

Los Pozos (AA:12:91) is a large (approximately 1.25 x 1.0 km) open air site located on the east floodplain of the Santa Cruz River in the northwestern region of present-day Tucson, Arizona. The site, with two main loci defined -- the Central Cluster and the Sweetwater Locus -- was discovered and excavated in 1995 and 1998 during the expansion of the Interstate-10 highway. Archaeologists from Desert Archaeology, Inc., led by David Gregory did a remarkable job of excavating and analyzing the site, revealing it to have been an extensive settlement with evidence of hundreds of shallow residential pit structures with associated storage pits, hearths, refuse deposits, and most remarkably, an extensive system of canals (Gregory 1999, 2001; Gregory et al. 2007). The site was occupied between the Late Archaic period, beginning about 4000 cal BP years ago to the beginning of the Early Ceramic period, roughly 1800 cal BP (Gregory et al. 2007:36). This span, lasting approximately 2000 years, is called the Early Agricultural period, and is marked by the introduction of maize agriculture. Los Pozos is one of nearly 20 sites along a 25 km long stretch of the Santa Cruz River where it emerges from a narrow valley between the Tucson mountains to the west and the Santa Catalina mountains to the east. It is this permanent water supply that made the location so attractive to early Southwestern maize farmers, as it was to their hunting and gathering ancestors during the preceding millennia. Using flotation techniques, Gregory and his team recovered many charred maize remains and dated both cupule fragments and kernels from individual pit structures -- circular pit depressions ranging between 4.5 and 12 square meters in area (2007:99), with postholes, floors, hearths, internal small pit features, and a wide range of artifacts -- in order to establish the site's chronology. Combined with similar maize dating strategies from several of the other sites along the Santa Cruz river (see, for example, Las Capas and Clearwater), this provides one of the most comprehensive suites of AMS dated maize remains anywhere in the Americas (see Mabry 2008:55-71).