Reconstructing the formation and land use history of the Mound 2 depression at Río Viejo, Oaxaca, Mexico Michelle Goman a, * , Arthur A. Joyce b , Raymond Mueller c , William D. Middleton d a Sonoma State University, United States b University of Colorado Boulder, United States c Richard Stockton College of New Jersey, United States d Rochester Institute of Technology, United States article info Article history: Available online xxx Keywords: Mexico Holocene Paleoenvironment Land use Prehispanic abstract Archaeological and geoarchaeological work in the lower Río Verde Valley, Oaxaca, Mexico reveal a varied spatial relationship between the prehistoric inhabitants and this dynamic floodplain region over the last 3000 years. Significant demographic expansion occurred by the Late Formative period following flood- plain aggradation resulting from a change in stream hydrology and morphology. During the Classic and Postclassic periods, major shifts in settlement and land use occurred, primarily from the productive floodplain to the piedmont. The archaeological site of Río Viejo has played a pivotal role in the political and social history of the valley. Archaeological data indicate the site was occupied from the Middle Formative to the Early Postclassic and was an urban center and the political seat of the region during the Terminal Formative and again in the Late Classic. Four large depressions are associated with mounded architecture at the site. We collected paleoenvironmental and geoarchaeological data from the Mound 2 feature. A synthesis of this multi-proxy data has enhanced our understanding of site formation, occu- pation, and land use from the Late Formative to Postclassic times. The analysis indicates that the depression associated with Mound 2 was originally a borrow pit on the floodplain that was enhanced and augmented by monumental mound building. The area around Mound 2 was the focus of domestic and agricultural use during the Terminal Formative. An apparent cessation of activity around Mound 2 occurred during the Early Classic, which is consistent with a significant contraction in population at the site at this time. Activity resumed at Mound 2 in the Late Classic and continued until at least the Early Postclassic. These changes in occupation history appear to have resulted from political developments within the valley. Ó 2014 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction The lower Río Verde valley of Oaxaca, Mexico has a long and complex history of human settlement (Fig. 1). The earliest evidence for permanent occupation dates to the early Formative period (3900e2755 cal B.P.; Hepp, 2011). However, significant increases in the regional population started in the Middle Formative (2755e 2350 cal B.P.), at a time when environmental changes in the valley began to take effect. These changes resulted in the development of a rich ecological setting for human settlement (Goman et al., 2005; Joyce, 2010; Mueller et al., 2013). A politically centralized polity developed during the Terminal Formative period (2065e 1620 cal B.P.) with its political seat at the site of Río Viejo (Joyce, 2010, 2013; Joyce and Barber, 2011). Archaeological research over the past thirty years has yielded a detailed history of the site’s changing significance through time in terms of cultural and societal development until its ultimate abandonment in the Late Postclassic (740e505 cal B.P.). An unusual set of architectural features at Río Viejo are large, oval depressions associated with architectural platforms (Joyce, 1999a). Four of these features have been identified, although un- fortunately two have been disturbed by recent road construction. These depressions are similar to borrow pits also found at the sites of Charco Redondo and San Francisco de Arriba, both sites with substantial monumental architecture (Gillespie, 1987; Workinger, 2002). The largest of these sunken features covers 2 ha and is associated with Mound 2, a multi-use platform that supported both * Corresponding author. Sonoma State University, Geography and Global Studies, 1801 East Cotati Ave, Rohnert Park, United States. E-mail address: goman@sonoma.edu (M. Goman). Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint http://dx.doi.org/10.1016/j.quaint.2014.02.028 1040-6182/Ó 2014 Elsevier Ltd and INQUA. All rights reserved. Quaternary International xxx (2014) 1e12 Please cite this article in press as: Goman, M., et al., Reconstructing the formation and land use history of the Mound 2 depression at Río Viejo, Oaxaca, Mexico, Quaternary International (2014), http://dx.doi.org/10.1016/j.quaint.2014.02.028