The Ancient World
Firing high-tech lasers, Thomas Garrison 鈥�00 uncovers earthly secrets hidden beneath the Guatemalan rainforest.
Thomas Garrison nearly unearthed an ancient fortress in 2010.
Deep in Guatemala鈥檚 thick jungle, Garrison was in the early stages of an archaeological excavation of the Maya kingdom of El Zotz, where a fortress鈥攖he likes of which had never been seen before鈥攈ad been hidden under the dense brush for nearly 2,000 years.
鈥淚 was probably within about 100 feet of it and didn鈥檛 see it,鈥� Garrison remembers.
The jungle would keep its secret. This time.
Garrison, an assistant professor of anthropology at Ithaca College, has been leading archaeological digs in Guatemala and surrounding countries since 2002 to study the mysterious Maya civilization, which reached its peak around the eighth century. After the Maya鈥檚 cities were seemingly abandoned around A.D. 900, the lush rainforest buried the ruins. For more than a century, researchers have been slowly uncovering these ruins and piecing together the story of one of the greatest civilizations in the ancient world.
In the dense landscape鈥擥uatemala is said to mean 鈥渓and of trees鈥� in Mayan鈥攊t can take researchers years to map less than one square mile. But what if they could see right through the jungle?
In 2016, Garrison and colleagues from Tulane University turned to a laser-based technology called LiDAR (light detection and ranging) that allowed them to do exactly that. By firing thousands of lasers per second from an aircraft into the forest canopy below, the scientists were able to map the surface of 800 square miles of Guatemala鈥檚 Pet茅n forest.
What they discovered is changing just about everything we thought we knew about the Maya.
FIRST DEVELOPED to measure clouds in the 1960s鈥攁nd then used by NASA to map the surface of the moon in the 1970s鈥擫iDAR technology has been gaining popularity among archaeologists, especially in tropical areas. The vast majority鈥攁 full 92 percent鈥攐f LiDAR lasers bounce off the forest canopy, but the other 8 percent penetrate the treetops and brush, reaching the earth鈥檚 surface to create high-resolution maps that can detect slight changes in elevation to reveal man-made structures like buildings, roads and waterways.
鈥淚t wasn鈥檛 a matter of if we would find something with LiDAR in Guatemala. Our only question was: What we will find?鈥� Garrison says.
But the technology is expensive, and Garrison鈥檚 attempts to secure a grant for the project were unsuccessful. So he and his colleagues went to the Pacunam Foundation, a Guatemalan cultural- and natural-heritage preservation organization that has been funding Garrison鈥檚 El Zotz dig since 2012.
鈥淭hey decided that if they were going to do it, they were going to do it big,鈥� Garrison says.
And big they went. With funding from Pacunam, Garrison and a consortium of scientists from around the world worked with the National Center for Airborne Laser Mapping to collect data from nine archeological regions in the Maya Biosphere Reserve, in what amounts to the single largest survey in the history of Mesoamerican archaeology. The flights took place in July 2016. That November, Garrison went to the University of Houston to study the preliminary data.
鈥淚mmediately, it was clear there was an overwhelming density of new structures and settlements,鈥� Garrison says. 鈥淚 knew this was going to change how we think of the Maya.鈥�
The final LiDAR data revealed more than 60,000 new structures, including new urban centers with large plazas, four major ceremonial centers, large palaces and, in Tikal, one of the most thoroughly studied of all Maya cities, a 90-foot-tall pyramid previously believed to be a natural hill. But it also revealed extensive roadways, intricate agricultural systems and numerous defensive structures, most of which were hidden beneath the trees and buried underground.
Known cities were up to 40 times larger than archaeologists had previously thought, in some cases encompassing what they had believed to be isolated settlements. Agricultural fields occupied large portions of the lowland seasonal swamps surrounding urban regions; in some areas, the Maya had even used drainage channels to convert wetlands into fertile farmland.
It all points to a more sophisticated and interconnected society than previously believed, a society with a much larger population, too. The new data suggests the empire supported roughly 10 million Maya, more than double previous population estimates.
鈥淲e knew they had agriculture鈥攚e鈥檇 seen some hints of fields. But now, instead of looking at individual sites, we are seeing whole swaths of land, huge patterns moving across Guatemala. We can put it all together and see how this ancient civilization functioned as a whole,鈥� Garrison says.
鈥淭HE SURVEY is one of the most important developments in Maya archaeology in 100 years.鈥�
The jungle鈥攍ong the archaeologist鈥檚 great adversary鈥攈as suddenly become an ally.
In Europe and parts of Asia and Africa, access to archaeological sites is better and conditions are more favorable to digs. But for those same reasons, people have settled and farmed around and on top of ancient settlements, making it nearly impossible to get a full picture of their size, scale and interconnectivity.
鈥淲e鈥檝e been behind because of the lack of visibility and the challenges of working in the jungle,鈥� Garrison says. 鈥淣ow, we鈥檝e flipped the script鈥攂ecause of that jungle, we have one of the most well-preserved archaeological records anywhere in the world.鈥�
Complex field systems in the outskirts of ancient urban centers likely would not have survived in other conditions. And without the LiDAR data, Garrison says, it鈥檚 highly possible they never would have been found in Guatemala, either.
鈥淓ven if we deforested the whole area, you could step right on them and never know what you are looking at,鈥� he says.
The LiDAR data is so precise that Garrison and his colleagues can even see which sites have been looted and the crude paths looters have cut through the jungle to reach the sites.
Safeguarding and excavating the newfound sites鈥攂efore looters find them鈥攊s incredibly important to Garrison and his colleagues. They aren鈥檛 sharing the exact LiDAR data, in order to protect the sites鈥� locations, but they do hope publicizing the findings will help them secure funding for future digs. And archaeological discoveries of this magnitude are worldwide news. When Pacunam announced the LiDAR findings in February, it generated headlines from Costa Rica to Slovakia.
Garrison was interviewed by The New York Times, the BBC, NPR, The Washington Post and The Associated Press. He also appeared in National Geographic鈥檚 one-hour special about the study, 鈥淟ost Treasure of the Maya Snake Kings,鈥� which premiered in February.
It鈥檚 impressive recognition for an archaeologist still early in his career, and it all started at 糖心TV. Garrison, an anthropology major and scholar in the Toor Cummings Center for International Studies and the Liberal Arts, first visited the Maya region as a junior. He studied abroad in Mexico, completing an independent study project in Chiapas using a collection of Maya artifacts excavated in the 1950s. He then used CISLA funding to travel to Belize to participate in his first archeological dig.
鈥淚 was pretty much hooked on this career, so my adviser, [the late Professor of Anthropology] Harold Juli, counseled me and pointed me in the right direction.鈥�
Garrison used money he received as graduation gifts to travel to Honduras to participate in a dig that was run by Harvard professors, which, he says, 鈥渙pened the door for me to go to Harvard.鈥�
He was accepted as a Ph.D. candidate in Harvard鈥檚 anthropology program and, before he even took his first class, joined a team that would soon unearth a Maya mural. The significant discovery drew the attention of NASA, and Garrison had the opportunity to work with satellite imagery, setting him on a course to specialize in the application of digital technologies to the archaeological record.
鈥淚鈥檝e had a lot of things go my way,鈥� says Garrison.
AMONG THE NEW RUINS revealed by the LiDAR data is the illusive El Zotz fortress. It鈥檚 one of a series of defensive structures that has Garrison and his colleagues rethinking the role of warfare in the development of the Maya Empire.
鈥淲e knew the Maya practiced warfare, but we hadn鈥檛 seen much in the way of defensive infrastructure,鈥� Garrison says. 鈥淣ow, it appears conflict may have been a lot more important to the emergence and development of Maya cities than we thought.鈥�
While Garrison is planning to excavate the El Zotz fortress, the success of the LiDAR project has him thinking about other applications for the technology, too.
鈥淚鈥檇 love to go to Brazil, for example, and take a look at the Amazon,鈥� he says. 鈥淲hat鈥檚 under those trees?鈥�
Garrison is also keenly aware that what is of no use to him and his colleagues鈥攖he 92 percent of LiDAR data that maps the rainforest鈥攊s a treasure trove of information for botanists, environmental scientists and those working to combat illegal deforestation.
鈥淚t has huge implications for understanding tropical forest environments,鈥� he says.
Despite all that Garrison and his team have already learned, there is still much for researchers to analyze and thousands of new sites to excavate. The discoveries, Garrison says, have only begun.
鈥淭his data will provide a hundred years of work for many scientists.鈥�
