A team of researchers from the Geophysics Institute of the National Autonomous University of Mexico (UNAM) has uncovered a secret of the El Castillo or Kukulkan pyramid in Chichén Itzá, Yucatán: a smaller pyramid more than 2,500 years old.
Using a geophysical technique for imaging sub-surface structures called electrical resistivity tomography (ERT), the specialists were able to reveal the structure, over which El Castillo and a second pyramid uncovered in 1935 were built.
The same technique was used last year to reveal that the archaeological wonder was built over a cenote, or sinkhole, a common geological formation on the Yucatán peninsula.
During a press conference yesterday, the UNAM researchers presented the preliminary results of their studies, and explained that their non-invasive technique only requires several electrodes to be set up on the surface of a structure to be studied.
The newly-discovered pyramid is off-center with regard to El Castillo, and was built over the cenote at the base of the complex structure. It measures eight meters in height, plus two more for a shrine at the top.
The researchers estimate that the pyramid was built during the Puuc era, which developed in the region around the year 600 BC.
The limestone used to build the smaller pyramid is the same kind as that used in the larger archaeological site of Chichén Itzá.
While the 27-meter-high El Castillo pyramid has staircases on its four faces — corresponding to the four main points of the compass — the smaller, 16-meter-high pyramid discovered in 1935 has only one staircase, on its north side.
Given that the new pyramid is buried and the resolution offered by the ERT technique is low, the researchers can only guess about the structure’s staircase configuration.
This is the first time the technique has been used to “see” inside a historical or archaeological structure, said researcher René Chávez.
With it, he said, “we’ll be able to obtain a trove of information about the Maya and their evolution as a people.”
The researchers lamented that the National Institute of Anthropology and History (INAH) hasn’t yet created a national program that makes use of geophysical sciences in the study and prospecting of archaeological sites and historical buildings.
Source: Milenio (sp)