Archeology is changing rapidly with the development of advanced technologies. From now on, new analysis tools support specialists in their prospecting work in the field. LiDAR (Light detection and range) is the perfect example. This laser remote sensing, originally developed for military purposes, makes it possible to identify remains that are almost impossible to spot without because they have been camouflaged by vegetation, water and soil over time. Using this method, geologists have uncovered a vast Mayan area spanning nearly 1,700 square kilometers in northern Guatemala, hidden beneath the rainforest. Their research was published in the journal Ancient Mesoamerica on December 5, 2022. But other recent studies, conducted in Mexico in particular, report discoveries made possible thanks to LiDAR.
In just 45 minutes of flight, LiDAR had collected the same amount of data that would have taken decades by hand – archaeologist Chris Fisher in his TEDx “Scanning the Planet with LiDAR.”
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The remains of thousands of Mayan settlements hidden under vegetation
The first discoveries are the result of an aerial survey. Laser sensors are actually fired from the air, in short pulses. The time required for these push reflected from the surface and returned to the instrument is measured and converted to a plot using a GPS. LiDAR makes it possible, by precisely identifying the “anomalies” of a place, to build a three-dimensional map of it. A particularly effective technology for areas such as rainforests where visibility is limited, as lasers can penetrate thick tree canopy.
The researchers thus “scanned” the karst basin around the ancient cities of El Mirador and Calakmul in Guatemala. They eventually identified over 1,000 settlements there, dated to the Middle and Late Preclassic period (between ca. Maya). The remains of more than 400 cities or villages, several large platforms, pyramids, canals and reservoirs have been discovered, the researchers said in their study. According to its co-author Ross Ensley, a geologist at the Institute for Geological Survey of the Maya Lowlands in Houston (USA), interviewed by Live Sciencethe sites formed a “golden loop zone” for this ancient civilization:
The Mayans [s’y] is installed because she had the right mix […] The highlands provided a source of limestone, their main building material and dry land for living. Lowlands, mostly seasonal swamps or bajosspace for wetland agriculture as well as organically rich soil for use in terrace agriculture.
In Mexico, structures revealed remains of an ancient calendar
The researchers hope that LiDAR will help them explore yet other parts of Guatemala that have remained a mystery for centuries. Further north in Mexico, another research team is also trying to unlock the secrets of the Atlantic Gulf using this technology. They have already observed from the sky the remains of 415 ceremonial complexes built by Mesoamerican societies, the Olmecs or the Mayas, they state in an article in the journal The progress of science published on January 6, 2023. Even more, their location learned by the tool reveals that they were aligned in some way, suggesting to experts that they could have been used as a calendar along the Gulf Coast in ancient times.
⋙ The largest and oldest Mayan monument discovered in southern Mexico
Previous studies had already shown, based on evidence written on frescoes, that people living in Mesoamerica had developed a 260-day calendar as early as 300 or 200 BC. But this new discovery shows that such a system could have been used thousands of years earlier using large structures. The analysis of the newly identified, dated between 1,100 B.C. J.-C. Having such a calendar, the report’s authors note in a statement, would have allowed ancient people to plan their rituals and coordinate their agricultural activities. Some modern Mayan societies would still use a 260-day timeline, they explain elsewhere.
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