The timing and degree of reliance on maize agriculture in the Four Corners region of the American Southwest has been a central issue in studies that examine the origins of Puebloan society. Both diffusionist (various, but see Wills 1995) and migrationist (Berry and Berry 1986; Matson 1991) models have been proposed to explain the processes responsible for the movement of maize (Zea mays) north into the Four Corners region. This paper reports bone collagen stable carbon and nitrogen isotope values with paired accelerator radiocarbon dates on a large collection of human remains from western Basketmaker II/III sites in Marsh Pass and other areas of northeastern Arizona, as well as data on a small number of Puebloan remains including Chacoan Great House burials. The results make clear that Basketmaker II people were heavily dependent on maize by 400 B.C. Moreover, their degree of dependence is similar to that of Pueblo II and III farmers of the Four Corners region. These findings and the apparent rapidity of maize dependence support a migrationist model for the origins of maize farming in the northern Southwest.
Quality control for modern bone collagen stable carbon and nitrogen isotope measurements
