Technological analysis of Capacha pottery from the Colima Valley (western Mexico) by ED-XRF and thin-section petrography

Abstract

Capacha is one of the two earliest ceramic complexes known for western Mexico. It dates to a period when sociopolitical complexity was starting to develop in Mesoamerica. An understanding of Capacha pottery technology and production are therefore valuable windows into a critical moment of Mesoamerican cultural development. In this paper we analyze the composition of Capacha pottery samples from two sites in the Colima Valley (Colima, Mexico) by means of energy dispersive X-ray fluorescence (n = 100) and thin-section petrography by optical microscopy (n = 42), along with 15 geological clay samples. We look for Capacha pottery compositional diversity, availability and compositional variability in clay deposits in and outside the Colima Valley, and compositional matches between archaeological ceramics and clay deposits. The results indicate that the large majority of pottery analyzed is compositionally homogeneous, in contrast with the wide variation found in macroscopic traits. The results further indicate that Capacha pottery was manufactured in the Colima Valley with largely unprocessed clay(s) obtained locally, with the clay sources closest to the sites sampled providing the best compositional matches. A wide variation in pottery macroscopic characteristics, together with a strong compositional homogeneity of clay deposits over large parts of the Colima Valley, strongly warns against explaining the compositional homogeneity found in the pottery as purely the result of cultural conditioning and standardized cultural practices, with environmental constraints perhaps playing the biggest role in this outcome. This study presents the largest archaeometry-based study of Capacha pottery and the raw materials used in its production.