4750-year-old Megalithic Stone Plaza Discovered in the High Andes of Peru

The Callacpuma archaeological site, nestled in the Cajamarca basin of the northern Peruvian Andes, is renowned for its extraordinary cave paintings. These artworks, estimated to be approximately 15,000 years old, are unique in America and provide a fascinating glimpse into prehistoric times.

The ancient creator of these paintings selected the depths of the caves as their canvas. This choice indicates to researchers that these locations held spiritual and religious importance.

A recent investigation of the Callacpuma site reveals that the people who lived here were not only creative artists but skilled builders as well.

During their research on ancient structures at Callacpuma, two anthropology professors from the University of Wyoming have unearthed one of the oldest circular plazas in Andean South America.

This significant discovery highlights the monumental megalithic architecture, a construction style characterized by the use of large, upright stones without any mortar.

In their study, “A Monumental Stone Plaza at 4750 BP in the Cajamarca Valley of Peru,” published in Science Advances, Associate Professor Jason Toohey, project lead, and Professor Melissa Murphy explain the plaza is constructed using massive megalithic stones arranged vertically. This technique of construction has not been seen in the Andes before.

“The circular plaza is approximately 18 m in external diameter and 16 m in internal diameter and is formed by two concentric walls of megalithic, unshaped and unmortared, stones set vertically and closely spaced. The associated rectangular plaza is bounded by what seems to be a single-course, low wall.

All other walls recorded at Callacpuma are of double-faced cut stone masonry set in mortar, the standard construction format for later time periods throughout the Cajamarca region,” the researchers write in their paper.

Radiocarbon dating estimates the initial construction of this structure to have taken place approximately 4,750 years ago, during the Late Preceramic Period. This makes it one of the earliest examples of such architecture in the Americas.

“This structure was built approximately 100 years before the Great Pyramids of Egypt and around the same time as Stonehenge,” Professor Toohey says.

The dates indicate that the circular plaza at Callacpuma holds the prestigious title of being the earliest example of monumental and megalithic architecture in the Cajamarca Valley.

Furthermore, it’s one of the pioneering examples in ancient Peru, making it a significant landmark in architectural history.

“It was probably a gathering place and ceremonial location for some of the earliest people living in this part of the Cajamarca Valley.

These people were living a primarily hunting-and-gathering lifestyle and probably had only recently begun growing crops and domesticating animals,”  Professor Toohey explains.

At the site, the scientists also recovered artifacts related to life in the past and collected charcoal samples for dating.

“Distinctive artifacts include two miniature cuplike vessels, one of a soft stone and another ceramic, that were recovered from both the area of small rooms in the eastern side of the plaza and the corridor or entryway at the west edge of the plaza.

Excavation also uncovered 10 quartz crystals and a small unworked nodule of what is probably lapis lazuli from within the area of rooms, as well as two small fragments of worked anthracite probably representing small edge fragments of at least one mirror.

Five small stacks of ceramic serving bowls were also found within the corridor, one associated with the southern entrance and four associated with the possible entrance on the western edge of the plaza.

Features were formed by the stacking of three to five hemispherical shaped bowls. These were all encountered within contexts of jumbled rocky fill within these architectural zones, which represents an intentional filling of what had previously been a corridor.

These ceramic stacks are believed to have been offerings associated with the formal closure of the southern entrance and perhaps of the corridor; they may in fact represent the closure of the circular plaza itself,” the study informs.

In their study, the two professors conclude, “it is likely that the plaza was constructed during the Late Preceramic period, as early as 2850 BCE. We believe that the plaza continued to be used as a ritual space, at least periodically, through the Initial period and Early Horizon during which ceramics were deposited.”

The study was published in the journal Science Advances