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ResearchThe Spread of Maize to the Colorado Plateau (page 1 of 2)

Author: R.G. Matson, from: Matson, R.G. 1999. The Spread of Maize to the Colorado Plateau. Archaeology Southwest 13: 10-11.


The prehistoric populations known as Basket-maker II (BM II) have long been recognized as an early stage in the Anasazi cultural sequence, the tradition that gave rise to the modern Pueblo Indians. Basketmaker II was named for the extraordinary collections of baskets and other perishable materials recovered from dry shelters and cave sites on the Colorado Plateau in the late nineteenth and early twentieth centuries. BM II dates from the late centuries B.C. to about A.D. 400.

In the last 15 years our understanding of Anasazi origins has changed dramatically, partly as a result of the convergence of research on the Colorado Plateau and elsewhere in the Greater Southwest. Migration theories have become an essential part of our understanding of Anasazi origins, and BM II populations now appear to have derived in part from one or more migrations from farther south. This new understanding is based on three findings: the discovery of Early Agricultural period settlements dating to at least 1100 B.C. in southeastern Arizona and northern Chihuahua; the discovery that most BM II populations were maize cultivators; and an emerging consensus about ethnic differences among BM II groups.

Changing Perspectives and New Data

In 1985 I proposed that the earliest evidence for maize cultivation in the Greater Southwest would be found in the lowland floodplains of the Basin and Range Province in southern Arizona and New Mexico and northern Sonora and Chihuahua. Direct AMS dating of early maize remains from central Mexico indicates that maize was domesticated around 3500 B.C. The earliest maize-based villages in Mexico currently date no earlier than about 2500 B.C., although such settlements spread very rapidly across Mexico after about 2000 B.C. Direct dates on maize from the Greater Southwest older than 1700 B.C. suggest that the northward spread of maize cultivation was extremely rapid. One possibility is that this was accomplished through the migration of maize farmers into floodplain niches suitable for cultivation. If this hypothesis is correct, one would expect the earliest maize-based villages to be found not on the Colorado Plateau, but in the Basin and Range Province to the south. I also reasoned that the Anasazi tradition, and thus the Pueblo peoples, might be the end result of such a process.

Unknown to me, evidence for maize cultivation associated with pithouse settlements and dating to at least 1100 B.C. had just been discovered at the Tucson Basin site of Milagro by Bruce and Lisa Huckell. More recent work has extended the date of maize cultivation in this area back to at least 1500 B.C. By around 600 to 700 B.C., relatively large pithouse settlements are found along the Santa Cruz River floodplain in the Tucson Basin. The site of Cerro Juanaqueña, in northwestern Chihuahua (Hard and Roney, 1999), has produced three maize dates of about 1100 B.C. as well as projectile points similar to those found in contemporaneous sites in the Tucson Basin. Recently, David Hyland and his colleagues reviewed the perishable, chronological, and cultigen evidence for the Jornada Basin in New Mexico. They conclude that at least one migration from Mexico occurred, introducing maize agriculture and new styles of perishables.

Thus, an accumulating body of data supports the hypothesis that the maize-cultivating populations represented by San Pedro Cochise and related cultures were migrants from farther south.

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