3D scans reveal elaborate art carved into an Alabama cave more than 1,000 years ago
Carvings too faint for the naked eye shown in detail using a process called photogrammetry
Ancient art once lost to time is visible again thanks to modern technology and researchers who weren't afraid to spend long hours in muddy, narrow, pitch-black caves.
Archeologists and photographers have used a 3D photography technique to uncover detailed carvings that were etched onto cave ceilings beneath northern Alabama between 1,000 and 1,800 years ago.
Among the findings are four human figures, nearly two metres tall, decked out in elaborate Indigenous regalia, a coiled rattlesnake with a forked tongue and a three-metre long serpent.
"When you're standing in the cave — or in this case, crawling in the cave — they don't look like anything, because you can't see them. They're so faint on the ceiling that they don't really show up to the naked eye," ancient art photographer Stephen Alvarez, told As It Happens guest host Helen Mann.
"But what we found is that if we 3D scan that ceiling, we could make out these fantastic figures."
Alvarez is the founder of the Ancient Art Archive, a non-profit that digitally records and preserves ancient art. He teamed up with University of Tennessee archeologist Jan Simek and U.S. Geological Survey technician Alan Cressler to capture and study the faded carvings in Alabama's 19th Unnamed Cave.
Their findings were published this month in the journal Antiquity.
Dirty work in dark spaces
Art was first discovered in the cave in 1998, but the carvings, etched to a thin layer of mud, had faded over time.
To capture the images in all their former glory, Alvarez and his colleagues used a technique called photogrammetry, which involves snapping thousands of overlapping photographs, then using computer software to stitch them together in a three-dimensional space.
"You end up with a huge data cloud of exactly where everything is in 3D space on the ceiling, and from that we can shine lights on it virtually and begin to identify figures that are otherwise invisible," Alvarez said.
But while the technology is state of the art, the work itself is down and dirty.
Alvarez had to spend hours in the dark, wet, twisting caves taking more than 16,000 photographs, sometimes in spaces where the ceiling was only 30 centimeters above the ground.
"My knees still hurt when I think about doing the work," he said.
Watch: Time-lapse video of Stephen Alvarez working in the 19th Unnamed Cave:
But it's nothing compared to how much must have gone into creating the art in the first place.
The figures appear to form a larger work of art, Alvarez says, potentially telling a story, stretched out over more than 5,000 square metres, through winding, narrow caves where no natural light could possibly reach.
"They were doing this without ever being able to see the entire composition they were putting together," Alvarez said. "It just shows the genius of these 2,000-year old artists."
Radiocarbon dating places the artwork in the Middle and Late Woodland periods, between 500 and 1000 A.D.
The artists would have used homemade torches made of reeds to light their way, possibly working in teams — one person to hold the torch, and another to carve.
While researchers initially believed the carvings to be finger drawings, the intricate details revealed with the 3D scanning suggest the use of more precise tools.
The whole thing left Alvarez in awe of its creators.
"Our technology is so good that their technology seems primitive," Alvarez said. "However, intellectually, they were our equals."
What does it all mean?
According to the study, many Indigenous people who populated what is now Alabama during that era believed caves to be "pathways to the underworld," and the art could potentially have spiritual or ritualistic meaning.
Dustin Mater, a Chickasaw citizen and artist who works with Ancient Art Archive, told the New York Times that some of the figures feel similar to ones he's learned about in stories passed down by tribal elders.
"It is almost speculative, but there are nuances today that are carried forward into our traditions and in our stories," said Mater, whose ancestors were forcibly removed from northwest Alabama in the 1800s. "Living cultures take symbols and then revivify them and give them meaning."
Alvarez concedes we may never know the true motivation behind the work — but that's OK.
"It is art," he said. "And you don't have to know everything about art to appreciate it, to be awed by it, to be moved by it. And so not knowing in many ways makes us appreciate it more."
Written by Sheena Goodyear. Interview with Stephen Alvarez produced by Aloysius Wong.
- An earlier version of this story described the area of the cave engravings as 5,000 square miles. In fact, it is 5,000 square metres.May 10, 2022 10:05 AM ET