Scott Ortman,(Department of Anthropology) will present a free Archaeological Institute of America (AIA) lecture, “Winds from the North: resolving one of the great mysteries in American archaeology,” 7 p.m., Wed., Oct. 2, at the University of Colorado Museum of Natural History. The origins of the Northern Rio Grande Pueblos and the collapse of Mesa Verde society represent two iconic episodes in American archaeology. Despite a century of research however, there is still not a consensus on how, or even if, these two events are related.