North American Database of Archaeological Geophysics
North American Database of Archaeological Geophysics
Abstract/Summary:
Project Name: Teotihuacan, México, Mexico;
Reference: Manzanilla, L., L. Barba, R. Chávez, A. Tejero, G. Cifuentes, and N. Peralta (1994). Caves and Geophysics: An Approximation to the Underworld of Teotihuacan, Mexico. Archaeometry 36(1):141-157 (used with permission).
Caves had a multitude of functions and meanings for Prehispanic peoples, including shelter, habitation site, place of rites associated with lineage and passage, astronomical observatory, quarry, dwelling of the gods of water and those of death, mouth or womb of the earth, underworld, and fantastic space. Our curiosity was awakened with respect to the probable existence of a system of tunnels and caves in Teotihuacan, and its possible role as a model of the underworld of Tlalocan. The general objective of our project consists of the localization and definition of tunnels and caves which are of interest to archaeology because of their potential ritual or economic use. The following studies were undertaken as a consequence:
(1) A geological survey
in order to determine the distinct types of volcanic phenomena present in the
region.
(2) A detailed survey
of the visible caves and depressions in the north part of the Teotihuacan Valley,
in order to register their coordinates, azimuths, and lithological contexts.
(3) Geophysical analyses in the sectors intermediate between depressions to
detect anomalies associated with the presence of cavities and to trace the tunnels.
In order to confirm the magnetic results and locate the tunnels precisely, several
electrical profiles were measured on top of the magnetic profiles.
(4) In addition, exploratory drills were made to obtain cores of the subsoils
associated with certain anomalies. Our interest over the last few years in the
presence of tunnels and caves in the Teotihuacan Valley is based on the belief
that the selection of the site of the first Prehispanic urban centre in the
northwest part of the region is intimately related to this phenomenon.
In order to study the problem of the tunnels and eaves from an archaeological viewpoint, we initiated a regional geophysical survey of the Teotihuacan Valley which included the east flank of the Pyramid of the Moon. Recently an intensive study of the area around the Pyramid of the Sun was carried out, this sector was associated with a tunnel of great ideological significance, proposed as the cause for the erection of the largest structure of the ancient city of Teotihuacan. It was further proposed that this constituted the most sacred place in the urban centre. This particular tunnel should he part of a larger group. Therefore, we undertook a detailed geophysical analysis of the plaza in front of the pyramid, as well as an area in the back, in order to define its continuity with other cavities.
At the beginning of this study we had data concerning a tunnel described by Heyden (1975 and 1981) and caves visible in depressions near the Pyramid of the Sun. One of these, located towards the south margin of our magnetic grid was studied in depth. The goal of the research reported here was to obtain information on the intermediate spaces between these caves and the known tunnel under the Pyramid of the Sun. The correlation of the geoelectric profile TEO-1 and the magnetic information shows the presence of a cavity that is probably the continuation in a westerly direction of the tunnel described by Heyden (1975). Electric profiles TEO-5 and TEO-4 show that the continuation of the tunnel under the Pyramid of the Sun towards the east is feasible, confirmed also by the magnetic data. Towards the east, the magnetic pattern seems anomalous indicating the presence of a series of basalt dikes surrounded by partially filled hollow spaces or sectors of porous materials, as seen in TEO-2, leading us to believe that the tunnel under the Pyramid of the Sun forms part of a more complicated system of tunnels. The opening of this system is located in the depression to the east where a number of caves are visible.