T he origins of Basketmaker people and the importance of maize in their diets are top- ics of ongoing debate. To address these issues, we report accelerator radiocarbon dates and stable carbon and nitrogen isotope ratios on Bas- ketmaker and Puebloan burials from the Four Cor- ners region of the American Southwest and compare these data to previously published find- ings on Basketmaker diets at Talus Village and else- where in southwestern Colorado, Utah, and Arizona. Forty of the 42 burials in this study are directly dated, 33 are Basketmaker and include samples from White Dog Cave, Kinboko Cave I and other well-known early Basketmaker sites in the Marsh Pass region of northeastern Arizona (Fig- ure 1). These data provide yet another body of evi- dence for relatively heavy reliance on maize prior to the beginning of the Christian era in support of previous work by other researchers at Basketmaker II sites in the region. Between 1914 and 1923, Alfred V. Kidder, a young archaeologist with a new Ph.D., and Samuel J. Guernsey, an artist with the Peabody Museum at Harvard, explored various caves and rock shelters in the vicinity of Marsh Pass and Monument Val- ley in northeastern Arizona (Guernsey 1931; THE STABLE- AND RADIO-ISOTOPE CHEMISTRY OF WESTERN BASKETMAKER BURIALS: IMPLICATIONS FOR EARLY PUEBLOAN DIETS AND ORIGINS Joan Brenner Coltrain, Joel C. Janetski and Shawn W. Carlyle 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 depen- dent 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. El grado y momento de dependencia de agricultura maízana en la región de las Cuatro Esquinas del sudoeste de norte américa han sido los temas centrales en los estudios que examen los orígenes de la sociedad Puebloana. Los modelos de difusionismo (varias, vea Wills 1995) y migraciónismo (Berry y Berry 1986; Matson 1991) han sido propuestos para explicar los procesos responsables del movimiento de maíz (Zea mays) al norte hacia el interior de la región de las cuatro esquinas. Este artículo presenta datos de cocientes de isótopos carbonos y nitrógenos de colágeno que ha sido radiocarbono fechado con un aceler- ador de una grande colección de huesos humanos de los sitios II/III de los Basketmaker del oeste en Marsh Pass y otras áreas del nordeste de Arizona, al igual que datos similares de una cantidad pequeña de huesos Puebloanos incluyendo enterramientos del Chacoan Great House. Los resultados afirman que la gente de Basketmaker II era completamente dependiente de maíz con la llegada del ano 400 a.c. Además, su grado de dependencia es semejante a la dependencia de los agricultores de los Pueblo II y III de la región de las Cuatro Esquinas. Estos resultados y aparentemente rapidez hacia la dependencia de maíz apoyan un modelo migraciónisto para explicar los orígenes del cultivo de maíz en la parte norte del sudoeste. Joan Brenner Coltrain ■ Department of Anthropology, University of Utah, Salt Lake City, Utah 84112 (coltrain@anthro.utah.edu) Joel C. Janetski ■ Department of Anthropology, Brigham Young University, Provo, Utah 84602 (joel_janetski@byu.edu) Shawn W. Carlyle ■ Department of Anthropology University of Utah, Salt Lake City, Utah 84112 (carlyle@anthro.utah.edu) American Antiquity, 72(2), 2007, pp. 301–321 Copyright ©2007 by the Society for American Archaeology 301 AQ72(2) coltrain 4/4/07 4:47 PM Page 301