Geoarchaeology of the Boca Negra Wash Area, Albuquerque Basin, New Mexico, USA Vance T. Holliday, 1, * Bruce B. Huckell, 2 James H. Mayer, 3 Steven L. Forman, 4 and Leslie D. McFadden 5 1 Departments of Anthropology and Geosciences, University of Arizona, Tucson, AZ 85721 2 Maxwell Museum of Anthropology, University of New Mexico, Albuquerque, NM 87131 3 Department of Geosciences, University of Arizona, Tucson, AZ 85721 4 Luminescence Dating Research Laboratory, Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 80607-7059 5 Department of Earth & Planetary Sciences, University of New Mexico, Albuquerque, NM 87131 Dozens of Paleoindian sites, including the Boca Negra Wash (BNW) Folsom site (LA 124474), are scattered across a basalt plateau (the West Mesa) on the western side of the Albuquerque Basin, and adjacent uplands. The BNW site, like many others in the area, is located near a small (~60  90 m) playa basin that formed in a depression on the basalt surface and was sub- sequently covered by an eolian sand sheet (Unit 1) dated by OSL to ~23,000 yr B.P. Most of the basin fill is ~2 m of playa mud (Units 2 and 3) dating ~13,970 14 C yr B.P. (17,160–16,140 cal yr B.P.) at the sand–mud interface to ~2810 14 C yr B.P. (~2960–2860 cal yr B.P.) at the top. C/N ratios suggest that the BNW playa basin probably held water more often during the Folsom occupation; stable carbon isotope values indicate C3 vegetation was more common as well, but C4 grasses became dominant in the Holocene. Cores extracted from four playa basins nearby revealed a similar stratigraphy and geochronology, documenting presence of wetlands on playa floors during the Paleoindian occupation of the area. © 2006 Wiley Periodicals, Inc. INTRODUCTION The Albuquerque Basin in the central Rio Grande Valley (Figure 1) has long been known to archaeologists for its rich Paleoindian record (e.g., Hibben, 1941; Dawson and Judge, 1969; Judge and Dawson, 1972; Judge, 1973). The area has one of the highest concentrations of reported Paleoindian sites in the Southwest. Most of these are on terraces or other uplands in proximity to the Rio Grande. Very little is known of the stratigraphic or paleoenvironmental context of these Paleoindian localities, Geoarchaeology: An International Journal, Vol. 21, No. 8, 765–802 (2006) © 2006 Wiley Periodicals, Inc. Published online in Wiley Interscience (www.interscience.wiley.com). DOI:10.1002/gea.20139 *Corresponding author; E-mail: vthollid@email.arizona.edu.