Understanding the maize grinding technology at Cerro Juanaqueña, Chihuahua, Mexico

In Southwestern archaeology it has long been thought that early forms of maize had a hard corneous endosperm while later in time varieties emerged that had a softer, floury endosperm. The emergence of floury endosperm has been associated with not only shifts in mano and metate forms but perhaps with major shifts in the role of maize in ancient societies. The opportunity to further evaluate the relationship between endosperm type and grinding technology emerged with the discovery of enigmatic, large basin metates dating to the Early Agricultural Period from the site of Cerro Juanaqueña. This thesis presents the results of 60 grinding experiments designed to examine the processing efficiency of the large basin metates found at that site in Chihuahua, Mexico. Experiments were conducted to compare grinding efficiency of the large basin metates in relation to trough metates when grinding maize with different endosperm types. The data from the 60 grinding experiments show that the large basin metate form processes pop and flint endosperm maize varieties more efficiently than trough metates. These results are statistically significant. In contrast the difference between trough and basin forms while processing flour endosperm maize was slight. The results of this thesis aids in understanding the spread of maize processing technology that facilitated the spread and adoption of agriculture in the American Southwest and northwest Mexico.