A detection technology identified 478 ceremonial centers of the Olmec culture in southern Mexico

Remote sensing of a large region of Mexico has revealed hundreds of ancient Mesoamerican ceremonial centers, including a large one at a site important to ancient Olmec culture, known for its colossal stone heads.

The remote sensing method known as LIDAR, for its acronym in English, identified 478 ceremonial centers in areas that were home to ancient Olmec and Mayan cultures dating from approximately 1100-400 BC (BC), researchers said Monday.

The study was the largest of its kind involving ancient Mesoamerica – a cultural region comprising the southern half of Mexico and Central America-, covering the entire state of Tabasco, southern Veracruz and parts of Chiapas, Campeche and Oaxaca.

LIDAR is a device that allows to determine the distance from a laser emitter to an object or surface using a pulsed laser beam. The technology enters the vegetation and points out structures that would not otherwise be seen.

A large ceremonial center was located at the early Olmec site called San Lorenzo, which is located in Veracruz, in the lowlands near the Gulf of mexico, and which was at its peak approximately between 1400 and 1000 BC

The Olmecs represented the oldest known major Mesoamerican civilization and are believed to have influenced later cultures, including the Maya.

University of Arizona archaeologist Takeshi Inomata, who led the study published in Nature Human Behavior, said LIDAR detected a large, previously unknown, rectangular ceremonial space of dirt in San Lorenzo.

It measures about 1,000 meters by 275 meters, with 20 platforms around the edge slightly raised above it.

Its purpose remains unclear, but it could have been a plaza where large numbers of people gathered for some type of ceremony, while the platforms surrounding the plaza may have had residences, Inomata said.

Olmec heads, each formed from a single basalt rock, are among the most evocative works of art from ancient Mesoamerica. The naturalistic facial features are carved in such a way that experts suspect they are actual representations of ancient Olmec rulers.

10 heads have been discovered in San Lorenzo. Inomata said there may be more of them undiscovered on related sites.

Many of the hundreds of ritual complexes identified in the study share common designs such as that of San Lorenzo. Several of these appear to have been built with orientations aligned with the direction of sunrise on specific key ceremonial dates.

“These centers were probably the first material expressions of the basic concepts of the Mesoamerican calendars,” Inomata said, detailing that these calendars were based on a 20-day unit, coinciding with the number of platforms around the ceremonial center of San Lorenzo.

Another even larger complex, described by Inomata and his colleagues last year, was found at the Aguada Fénix Mayan archaeological site in Tabasco, near the border with Guatemala.

This and other findings in the study, dating after that of San Lorenzo, suggest that the Olmecs and other peoples in the region exchanged ideas.

LIDAR has proven to be increasingly useful to archaeologists.

“The advantage of LIDAR is that it provides a three-dimensional view of the landscape and the modifications made by humans, ancient and modern, in the form of construction, transport, agriculture and water control infrastructure,” said LIDAR engineer Juan Carlos Fernández -Díaz.

“LIDAR also allows us to” see “the landscape and infrastructure that in many parts of the world is hidden under forest canopy,” added Fernández-Díaz, co-author of the study from the National Center for Airborne Laser Mapping at the University of Houston.


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