RECONSTRUCTING MID-LATE HOLOCENE SOIL SEQUENCES AND ANTHROPOGENIC IMPACTS WITHIN THE RIO GRANDE WATERSHED, NORTHERN NEW MEXICO

Significant work in New Mexico has recorded much important information about the anthropogenic environmental strategies among the agricultural communities of the Pueblo peoples, but far less is understood about the environmental impacts of and challenges faced by the various communities that preceded them. The dynamic small catchments that feed into the Rio Grande in Northern New Mexico provide a rare opportunity to link alluvial sedimentary deposits and associated environmental changes, directly to some of the oldest archaeological features in the region, as both have been exposed by recent increased erosion. During the Mid Holocene, the general region experienced a period of warming temperatures and drying environments, and much of the Archaic hunter-gather period is documented under these types of climatic conditions. In the Late Holocene, many regional climate proxies indicate a shift to generally wetter, cooler conditions, perhaps related to increased precipitation from the North American Monsoon pattern during this time. Such increased precipitation would have led to greater runoff into the valley alluvial systems, as well as higher water tables. This period also coincides with the Late Archaic human occupation of the region and the eventual transition to the early farming practices that characterize the Basketmaker traditions. Our paper presents a range of preliminary geoarchaeological, paleobotanical, and isotopic techniques from two sediment sequences that have been dated to the Mid to Late Holocene, and both sequences contain archaeological features that date to these earliest occupations in the region. Our goal is to quantify shifting hydroclimate regimes and document human land use strategies and environmental response to during these early occupation areas in the Upper Rio Grande watershed.