Unlocking secrets of the past

They aren’t using whips or wearing leather fedoras, but scientists at Colorado State University have taken advantage of advances in remote sensing technology to make archaeological discoveries about which Indiana Jones could only dream.

Chris Fisher, an associate professor and archaeologist in CSU’s Department of Anthropology, and Assistant Professor of Geography Stephen Leisz have used Light Detection and Ranging, or LiDAR, technology to peel back layers of dense jungle to discover two “lost” ancient cities in Mexico and Honduras.

In the past, LiDAR was used for mapping and to help scientists examine the natural and manmade worlds a little more precisely than was available in the past.

The LiDAR works its magic from above. It is flown over the area that researchers want scanned, and in return, it produces highly detailed, three-dimensional images.

“That is a profound ability that has completely started to shake up the established way we do archaeology. It shattered already a lot of interpretations and assumptions we had about how people lived in the Americas,” Fisher said. He argues that LiDAR technology “will allow us to repopulate the Americas in a way we have never been able to do before.”

At Sacapu Angamuco in Michoacan, Mexico, Fisher said, the LiDAR technology is so efficient that it basically gleaned a decade’s worth of archeological research in about 45 minutes of scanning. The area is 350 kilometers northwest of Mexico City.

He sought out the technology after he and Leisz’s team walked the area and realized it was a much bigger settlement than at first thought. It was, in fact, a city. Fisher said he is impatient so he wanted a way to document the area without spending 10 years or more doing it.

They hired Merrick & Co., a firm that conducts LiDAR, to scan 8 square kilometers of the settlement. It found that the settlement is much bigger, more complex and better preserved than first imagined.

“The LiDAR documented things at such high resolution and with a great deal of accuracy. In this rugged topography and forest cover, I’m not sure we could cover that using normal archaeological techniques,” Fisher said. “In 45 minutes of flying, it gave a career’s worth of data. It was pretty tremendous.”

In Honduras, Fisher and Leisz are helping to make heads or tails of LiDAR scans of the remote and densely forested Mosquitia Coast. The area boasts some of the last remaining tropical rainforest in the region. Because of its rugged topography and inaccessibility, very little archaeology has been done there, Fisher said, although the area is known to have at least 200 archaelogical sites.

In a week’s time, the crew, including a film maker from Los Angeles who spearheaded the project, found enough evidence of an ancient civilization in the area that the country was able to put in place additional protections for the area, which already is a biosphere reserve.

“Archaeology is incredibly time consuming and pretty expensive and very painstaking work,” he said. “Before LiDAR, to get these kinds of data, we would have teams walk over every inch of the landscape recording all archaeology. Surveying one valley could be a career for somebody.”

In a week of scanning in Honduras, they documented almost three complete river valleys, he said. “It is really transforming how we get big scale records.”