Oxford. March 1 2007. Archaeologists working in Peru have revealed that the 13 towers of Chankillo, in the Casma Valley of Peru's coastal desert, mark the existence of sun cults that predate the Inca by 1,700 years. This research, carried out by former Earthwatch archaeologist Ivan Ghezzi (Pontificia Universidad Catolica del Peru) and Clive Ruggles (University of Leicester), is published in Science today.
The 13 towers are a line of structures that run north to south along the ridge of a low hill at Chankillo - a ceremonial site dating back to the fourth century B.C. From evident observation points on either side, the towers form a "toothed" horizon that spans the annual rising and setting arcs of the sun, indicating their use in solar observations.
To confirm this theory Ivan Ghezzi conducted excavations with volunteer teams from the international organization Earthwatch for three years. They looked at the alignments of the 13 towers and excavated what they believed to be a solar observatory. Earthwatch volunteers also took tree ring samples from well-preserved wooden beams that helped to date the site.
"Chankillo is arguably the oldest solar calendar that can be identified with confidence within the Americas," says Ivan Ghezzi. "Many indigenous American sites have been found to contain one or a few putative solar orientations but Chankillo provides a complete set of horizon markers and two unique and indisputable observation points."
Excavation of ancient buildings to the west of the towers revealed one corridor that was clearly an observation point for watching the sun rise over the toothed horizon. The end of the corridor was littered with offerings of pottery, shell, and stone artifacts not found elsewhere, indicating significant rituals associated with solar observations. A building to the east is in the exact mirror position of the western observation point, and is lined up to view the sunsets over the 13 towers.
The gaps between the towers are wide enough for just one or two sunrises to be observed in each. The regularity of the gaps suggests that the year was divided into regular intervals.
It is thought that plazas near the 13 towers provided a setting for people participating in public rituals and feasts directly linked to solar observations. However, the observation points themselves appear to have been highly restricted to individuals with special status. This, along with ceramic warrior figurines found at the site, suggest the authority of an elite few. As with the Inca Empire, two millennia later, sun worship and cosmology may have helped legitimize that authority.
"Chankillo was built approximately 1700 years before the Incas began their expansion," continues Ghezzi. "Although there is obviously no direct culture-historical relationship between the 13 Towers of Chankillo and the sun pillars of Cuzco, they are analogous as horizon markers for calendar purposes. Now we know these practices are quite a bit older, and were highly developed before the Inca."
This research will appear in the 2 March, 2007, issue of the journal Science, published by the AAAS, the world's largest general scientific organization. See http://www.sciencemag.org/, and also http://www.aaas.org/.
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Photos © Ivan Ghezzi