With Deb Nichols (Dartmouth) we are currently working with the largest sample of Early and Middle Formative ceramics ever chemically analyzed in central Mexico.  Part of this work is to start a regional reference database for the earliest Mesoamerican ceramics in the region.  We have also already identified a substantial interregional exchange network connecting several of the earliest sites in central Mexico, which helps to understand the rise of complex society in this important culture region.

Analysis of results is ongoing, but we have identified a number of significant patterns:

 

• Most ceramics reflect the compositions of materials available within close proximity of the location of archaeological recovery, which implies local production.
• There is a gradient of chemical and mineral compositions represented in the pottery fabrics that reflect geological variation across the region.
• Some ceramic types were clearly imported from other regions as they exhibit metamorphic or sedimentary rock fragments in the fabric that do not occur in the Basin of Mexico (a volcanic terrane).
• Imports came from as far away as the Gulf Coast, Oaxaca, Puebla, and Morelos.
• Some data indicates that sites within the Basin of Mexico also traded ceramics.
• Over time, sites in the region import fewer ceramics, and the ones that are imported come from more closely situated neighbors rather than over longer distances.
• The long-term pattern of interregional interaction shifts from externally focused prestige economies to more internally focused polities aiming to consolidate power within the region.
• This shift was accompanied by the formation of regional settlement hierarchies and the development of some of the earliest cities in Mesoamerica.