- Discovered artifacts reveal vanished Cahokia tribe’s culture
- Researchers use LiDAR for mapping Cahokia sites
- Cahokia used wood extensively, causing flooding
A huge Native American city spanning six square miles and home to around 20,000 individuals vanished from the Mississippi River basin over 600 years ago.
While the ‘Cahokia tribe mysteriously vanished, researchers have discovered artefacts from the society that may reveal clues about the community—its culture, language, and even its demise have all been lost to time.
A team of university academics recently unearthed pottery, tools, such as micro-drills,’ and wall trenches at the Illinois site that date back around 900 years.
Wood particles were also analyzed at the site. Researchers believe the Cahokia cut down trees for construction projects, degrading the soil and possibly causing flooding, which could have led to the tribe fleeing the city.
Students studying archaeology at Saint Louis University (SLU) and nearby colleges are conducting the dig.
Students drilled rectangular holes at the site, carefully removing earth to reveal fresh finds while safeguarding this UNESCO World Heritage Site.
Mary Vermilion, an associate professor of archaeology at SLU, told 5OnYourSide that the structures and pottery found here appear to date to the Sterling Phase of the Mississippian Period—approximately 1100 AD to 1200 AD—which is a critical point in the development of the chiefdom because it represents the apex.
The discoveries join hundreds of other complex artefacts at the site, including shells and pearls precision-drilled for various functions, including ‘conduits for human souls on their passage to the afterlife,’ according to academic Dr Laura Kozuch.
Unlike the Maya or Aztec people to the south, the Cahokia originated in the Mississippi Valley over a thousand years ago, approximately 700 AD, in what is now the state of Illinois, across the river from the current city of St. Louis in Missouri.
Civilization built an estimated 120 earthen mounds at its peak, forming the most fantastic city north of Mexico until European settlers arrived.
Many mounds resemble huge pyramids, with square corners at the bottom and levelled levels at the top.
Anthropologists believe that these mounds, especially the 100-foot Monk Mound, were used to raise, honour, and defend the residences of Cahokia’s municipal leaders.
However, just about a century before Columbus sailed into the Americas, the society responsible for constructing these spectacular monuments perished without explanation in 1350.
In addition to looking for artefacts, the SLU researchers collaborated with the US National Geospatial-Intelligence Agency (NGA) to map important Cahokia sites using a ‘Light Detection and Ranging’ (LiDAR) aerial drone, similar to the technology employed in the spy agency’s official work.
The best part was applying our tradecraft in a way that is not normal for us,” said agency surveyor Stacy ‘Craig’ Ackermann. “In this case, it was archaeology.”
NGA and SLU also investigated the area outside the lost city’s recognised to see if further mounds or other suitable archaeological sites could be concealed among Cahokia’s vast forests and marshlands.
“You can’t walk through some of that part,” said Philip ‘Casey’ Shanks, the intelligence agency’s drone programme manager.
‘That is why the UAS is the ideal tool for the job,’ says Shanks, who works in the agency’s Office of Geomatics.
The collaborative Cahokia Mounds aerial survey flew over 490 acres of the site, the largest single area ever studied by this US espionage agency using a drone and LiDAR technology.
LiDAR is a remote sensing technology that uses a laser to estimate surface distances and shapes while analysing.
The information gathered was then utilised to create a photogrammetric 3D foundational mesh model of the old city’s most outstanding landmark, the Monk Mound.
“There are many questions about Cahokia’s past that can be answered by remote sensing and LiDAR data,” said Justin Vilbig, a geospatial data scientist at the Taylor Geospatial Institute and doctorate student at SLU who is leading the study.
According to Vilbig, this provides a complete picture of the terrain, including where features were in relation to one another and what the Cahokians’ priorities were.
Vermilion’s Cahokia partnership involves 11 students studying anthropology, archaeology, geological surveying, and other related subjects.
Each contributes their distinct scholarly perspective to the project to write a senior thesis eventually.
‘I’m looking at wood usage,’ University of Vermont student Hal Nalamliang told local media.
Nalamliang spent a month at SLU to work on the dig.
‘There’s sort of a broadly acknowledged notion that the people of Cahokia used a lot of wood from their location,’ he added, ‘and that caused degradation to the soil, which produced flooding.’
Gus Krussel, an undergraduate junior at LSU, said his experience digging the Cahokia site has inspired him to become a professional archaeologist.
‘You can learn a lot about ancient societies doing this,’ Krussel said. ‘That’s what captivated me.’
He continued, ‘It’ll keep me in shape and busy. I would want something other than a desk job.
LiDAR (light detection and ranging) is a remote sensing technology that detects distance by firing a laser at a target and anaanalyzingat bounces back.
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The system, created in the early 1960s, combines laser vision with radar technology to measure distances.
The National Centre for Atmospheric Research pioneered its application in meteorology to measure clouds.
The term lidar combines ‘light’ and ‘radar.’
Lidar images objects using ultraviolet, visible, or near-infrared light. It can be employed on various targets, such as non-metallic objects, rocks, rain, chemical compounds, aerosols, clouds, and even single molecules.
A narrow laser beam can map physical characteristics at extremely high resolution.
This new technology enabled researchers to sketch the boundaries of dozens of newly discovered Maya cities hidden beneath dense jungle growth centuries after their original inhabitants had abandoned them.
Aircraft equipped with a Lidar scanner created three-dimensional maps of the surface by employing light as a pulsed laser connected to a GPS.
The tool enabled researchers to discover sites considerably faster than traditional archaeological approaches.
