Clay, lime, and economic security in Formative Period Valley of Puebla, Mexico

The central part of the Valley of Puebla, Mexico, has been an important source of lime in the Mexican highlands going back at least to the early 16th century when the town of Tepeaca was a seat of local political authority in the Aztec Empire.  Archaeological evidence indicates that lime processing was part of the local inhabitants' activities by the Middle Formative Period.  Furthermore, the available data suggest that pottery-making for exchange, at least on a regional level, was taking place by the Late Formative Period.  Both lime processing and ceramic manufacturing were performed on the same hillside, presumably by the same families, although the technologies involved were distinct.  Lime processing was done in open, shallow subhemispherical concavities, the bases of which lay in the underlying tepetate.  Ceramic firing facilities were more labor-intensive constructions, truncoconical in form.  These pits were dug through earth and into the underlying tepetate to depths of 34 to 90 cm, widening from apertures of perhaps 70 cm to floor diameters of as much as 198 cm.  Much greater control over firing temperatures was possible, and significantly higher temperatures were achieved, in the pottery facilities as compared to the lime processing pits.  The floors of the ceramic firing facilities were dark gray to black, similar to the floors of the lime pits, but the walls (both the fire-hardened earth above and the tepetate below) were orange to red in color to thicknesses of several centimeters.  Since little evidence exists of subsistence stress in this area during Middle and Late Formative times, these households were likely using these activities as a way to trade for necessary or desired items and as a subsistence risk reduction mechanism.

Ron Castanzo has conducted archaeological research, with a focus on Mesoamerica, since 1994.  After graduating from Penn State University (University Park, Pennsylvania, USA) in 2002, he began postdoctoral studies at the Smithsonian Institution (Washington, District of Columbia, USA), where he was introduced to the chemical characterization of ceramic pastes using neutron activation analysis.  In 2007, Ron joined the faculty of the University of Baltimore (Baltimore, Maryland, USA), a small public liberal arts institution, where he has built the anthropology curriculum.  His scholarly interests lie mainly in the archaeology of prehispanic Mexico and include the evolution of economic institutions, ceramic manufacturing, and population dynamics and change.  He has published papers on such topics as Formative Period settlement in the Valley of Puebla, ceramic manufacturing and kiln technology, and obsidian production.  He also has interests in historical archaeology in the City of Baltimore and State of Maryland.  In the near future Ron intends to continue his work involving the Formative Period in the Tepeaca area and to embark on a study of broad changes in settlement in the Puebla-Tlaxcala Region, while continuing to strengthen the anthropology and archaeology capability of his home institution.