Prehistoric Footpaths In Costa Rica Indicate Intimate Ties With Villages, Cemeteries

During the past two years, a team of graduate students, NASA archaeologists and remote sensing specialists led by Professor Payson Sheets spent much of their time mapping the small footpaths, many of which are invisible on the ground but visible by satellites. The team noticed portions of some footpaths were worn up to 3 meters deep by people who had trod them over the centuries approaching some of the cemeteries.

"People traveling such a path would see nothing of the cemetery until they actually entered it," said Sheets. "I suspect, inadvertently, this developed into a cultural expectation, a norm, that gained religious importance as the proper way to enter and exit a cemetery."

The team also found a "sub-path" -- a perpendicular spur off the main path -- that went straight up a hillside. The top of that hill is the only locality in the region from which people could view a particular cemetery known as Silencio from afar. In one case a village and a cemetery less than a mile apart had a hill in between them.

Instead of taking the path of least resistance and walking around the hill, they plodded up and over the top of the hill, creating a straight, deeply worn path opening right into the cemetery entrance, said Sheets.

A good example is the Poma cemetery in the Arenal Volcano region in the northwest Costa Rican rainforest, he said. There, two parallel footpaths eroded down about 2 meters, which eventually melded into one path and provided "entrenched exit and entry to the cemetery." Next year the team plans to trace the footpath back to the village of origin.

Sheets believes this beeline style to enter and exit cemeteries and villages became widespread over the centuries, when more complex societies took it to a higher level by constructing long, sunken roadways entering and exiting villages and cemeteries. A primary roadway from the Cutris site, for instance, which runs straight for many kilometers from the center, was excavated and found to be 30 meters to 40 meters wide and 3 meters to 4 meters deep as it entered the chiefdom center, home of the elite village rulers.

"It appears that the cemetery was not the only sacred place, but so was the territory between the village and the cemetery, and the proper path use was to access the cemetery along precisely the same path used by their ancestors," he said. "The process of entering and leaving cemeteries was part of a belief system that included ceremonial feasting, tomb construction and the breaking of special pottery, grinding stones and other ritual activities at the cemeteries," said Sheets.

Images of the tiny footpaths, some 1,500 years old, were made by a NASA aircraft and the commercial satellite, IKONOS, equipped with instruments that can "see" in the light spectrum invisible to humans. The infrared cameras picked up a unique "signature" that caused the paths to show up as thin red lines in the images.

Packing satellite data and GPS satellite receivers, Sheets, NASA archaeologist Tom Sever, NASA remote-sensing specialist Dan Irwin and CU students Errin Weller, Michelle Butler and Devin White took off on the trail of the ancient ones last summer.

One surprise was that about 90 percent of the ancient pottery sherds from the cemeteries apparently were brought in by people on the Pacific side of the drainage who toted them on paths to the cemetery.

"This is a fascinating situation," said Sheets. "It appears these people may have had a much more complex network of social, economic and religious contact between isolated villages on both sides of the divide than we would have expected."

The sherds evidence collected in late July indicated ceremonial funerals and elaborate feasting after burial -- which included cooking, eating, drinking, sleeping and the smashing of elaborate pots and stones on graves -- may have included very disparate groups.

"My research interests include understanding the everyday lives of ancient people and applying remote-sensing techniques to locate prehistoric sites," said doctoral student Errin Weller. "My experiences in central Costa Rica with CU-Boulder and NASA participants provided a singular opportunity to combine the use of high-resolution satellite imagery and archaeology."

Master's student Michelle Butler who plotted specific points along the footpath with GPS satellite receivers as part of her work, said the high-tech tools have a huge future in archaeology. "Being able to pinpoint paths and cemeteries used by people over 1,000 years ago is exciting work, and helps us develop a much better picture of who these people were and how they used the landscape."