The Southwest Symposium is just getting started at the Universidad Tecnológica de Paquimé, in Casas Grandes, Mexico. The official language of the conference is apparently Spanglish, with lots of switching between Spanish and English.

First up is Sam Jensen, giving an introduction to a session on historical trajectories of the Casas Grandes culture in Chihuahua, Mexico. He is providing an overview of the history of archaeology in Chihuahua.

Next us Matt Pailes of the University of Oklahoma. He is talking about the Archaic and early agricultural periods in northern Mexico. He highlights difference between Sonora, west of the Sierra Madre, where there is evidence for a long occupation but no population growth trend, and Chihuahua, east of the mountains, where there are no early dates, but a rapid increase in population after 1500 BC.

Now Mike Seary is talking about historical gravity during the Viejo Period to Medio Period transition in Casas Grandes culture. Connections to people, places, and historical knowledge drew people back to places and influenced historical trajectories.

The Viejo to Medio period transition around AD 1200 involved major changes in architecture, social organization, and other aspects of culture. But many Medio perio sites are built directly on top of Viejo period sites. Often later buildings were built directly on top of Viejo period buildings.

Viejo period structures were found by Charles DiPeso under the large Medio period site of Paquimé, but not well described in reports. Archives contain much more information.

Places gain historical gravity from the accumulation of events and memories. Ancestral worship was important to Vasas Grandes culture: dna evidence shows genetic continuity across the Viejo to Medio periid transition, and Medio period people maintained ties to earlier places that had historical gravity.