Los Pozos

Information

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).

ID Other ID Type Subtype Uncal BP (years) ± 1 σ (years) Median cal BP (years) Lower cal BP (years) Upper cal BP (years) δ13C Contaminated?
Beta-91143 MacroSample cupule 2050 50 2017 2141 1896 -7.5 No
Beta-91145 MacroSample cupule 2110 50 2086 2304 1948 -11.6 No
Beta-95632 MacroSample cupule 2090 80 2071 2309 1890 -11.3 No
Beta-125226 MacroSample cupule 2140 40 2129 2306 1999 -8.9 No
Beta-126950 MacroSample cupule 2110 40 2083 2300 1953 -10.2 No
Beta-124697 MacroSample cupule 2130 50 2115 2309 1991 -10.1 No
Beta-124698 MacroSample cupule 2150 60 2148 2320 1996 -10.5 No
Beta-125223 MacroSample cupule 2190 50 2217 2337 2060 -9.3 No
Beta-126332 MacroSample cupule 2070 50 2041 2288 1899 -10.1 No
Beta-126951 MacroSample cupule 2120 40 2095 2302 1992 -10.7 No
Beta-126328 MacroSample kernel 2140 50 2131 2309 1995 -8.3 No
Beta-124696 MacroSample cupule 2150 60 2148 2320 1996 -10.4 No
Beta-125225 MacroSample cupule 2160 30 2170 2308 2056 -10.5 No
Beta-95631 MacroSample cupule 2060 80 2036 2306 1831 -11.6 No
Beta-91142 MacroSample cupule 2150 50 2147 2310 2001 -7.6 No
Beta-125222 MacroSample cupule 2180 50 2205 2333 2051 -10.2 No
Beta-126949 MacroSample cupule 2190 40 2227 2332 2071 -10.6 No
Beta-124113 MacroSample kernel 3230 50 3451 3567 3364 -10.3 No
Beta-123603 MacroSample cupule 2240 40 2233 2341 2152 -11.7 No
Beta-124111 MacroSample kernel 3340 60 3575 3720 3410 -10.7 No
Beta-95628 MacroSample cupule 2190 80 2196 2345 2000 -11.3 No
Beta-123602 MacroSample cupule 2140 50 2131 2309 1995 -10.7 No
Beta-91140 MacroSample cupule 2140 60 2133 2321 1991 -2.5 Yes
Beta-91144 MacroSample cupule 2170 60 2182 2331 2005 -8.2 No
Beta-123599 MacroSample cupule 2190 50 2217 2337 2060 -11.7 No
Beta-124700 MacroSample cupule 2190 50 2217 2337 2060 -11.0 No
Beta-91147 MacroSample cupule 2240 60 2234 2353 2115 -8.0 No
Beta-126948 MacroSample cupule 2100 40 2073 2296 1951 -16.0 Yes
Beta-95630 MacroSample cupule 2110 80 2095 2319 1902 -10.7 No
Beta-91141 MacroSample cupule 2120 60 2103 2309 1949 -8.2 No
Beta-125224 MacroSample cupule 2230 40 2232 2338 2151 -10.1 No
Beta-123600 MacroSample cupule 2380 40 2420 2692 2335 -12.7 No
CAMS-34923 MacroSample cupule 4050 50 4539 4808 4418 Yes
Beta-123601 MacroSample kernel 2130 40 2112 2304 1995 -10.2 No
Beta-124699 MacroSample cupule 2100 60 2078 2306 1925 -10.9 No
Beta-91146 MacroSample cupule 2090 60 2066 2304 1900 -8.3 No
Beta-91148 MacroSample cupule 2140 50 2131 2309 1995 -9.6 No
Beta-95629 MacroSample cupule 2150 80 2147 2338 1950 -11.0 No
Beta-91149 MacroSample cupule 2160 60 2166 2324 2002 -6.7 Yes
Beta-124114 MacroSample kernel 3300 80 3535 3716 3365 -10.4 No
Beta-124112 MacroSample kernel 3140 50 3367 3465 3246 -10.7 No

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References Cited

Gregory, D. A. (editor)
    1999    The Early Agricultural Period Component at Los Pozos: Feature Descriptions and Data Tables. Technical Reports 1999-4. Center for Desert Archaeology, Tucson.

Gregory, D. A. (editor)
    2001    Excavations in the Santa Cruz River Floodplain: The Early Agricultural Period Component at Los Pozos.  Anthropological Papers 21. Center for Desert Archaeology, Tucson.

Gregory, D. A., M. N. Stevens, F. L. Nials, M. R.Schurr and M. W.Diehl
    2007    Excavations in the Santa Cruz River Floodplain: Further Investigations at Los Pozos. Anthropological Papers. No. 27. Center for Desert Archaeology, Tucson.

Mabry, J. B.
    2005    Diversity in early Southwestern farming and optimization models of transitions to agriculture. In Subsistence and Resource Use Strategies of Early Agricultural Communities in Southern Arizona, edited by M. W. Diehl, pp. 115-152. Anthropological Papers, No. 34. Center for Desert Archaeology, Tucson.

Mabry, J. B. (editor)
    2008    Las Capas: Early Irrigation and Sedentism in a Southwestern Floodplain. Anthropological Papers No. 28. Center for Desert Archaeology, Tucson.

Merrill, W. L., R. J. Hard, J. B. Mabry, G. J. Fritz, K. R. Adams, J. R. Roney and A. C. MacWilliams
     2009     The diffusion of maize to the southwestern United States and its impact. Proceedings of the National Academy of Sciences USA 106(50):21019-21026.