Objects made of copal resin: a radiological analysis

Resumen

Since pre-Hispanic
times, copal (Bursera bipinnata resin) has been used for different
purposes, from medical to ritual or religious, which promoted its
transportation from what is now the state of Guerrero to Morelos,
Puebla, and Mexico City, as has been verified by ethnographic
studies. During the Late Post-classic period, the resin was
transported to Tenochtitlan where it was transformed into different
objects such as bars, spheres, conglomerates, bases of sacrificial
knives, anthropomorphic figurines and diverse amorphous fragments.
The macroscopic and microscopic study of more than 300 copal objects
from the offerings of the Great Temple archaeological zone (Templo
Mayor) permitted the establishment of a methodology in the
manufacturing processes of several formal groups, which were then
corroborated by Computerized Axial Tomography, more commonly known
by its abbreviated names, CT scan or CAT scan. This radiological
technique, created for the study of living human organisms, is very
effective in archaeological applications, since it is not invasive
but still allows observation of the surface of an object as well as
its interior by means of virtual slices. Additionally, it allows the
detection of different densities of the components of the object,
making it possible to know the composition of different
materials.