In A Flash

LSU mounds oldest human-made structures in North America, study says

By: - August 22, 2022 9:27 am
An older white man in a blue shirt stands in front of the LSU Campus Mounds

LSU Department of Geology & Geophysics Professor Emeritus Brooks Ellwood led the study that has revealed new information on the LSU Campus Mounds including the discovery of thousands of years old charred mammal bone fragments and a coordinated alignment of both mounds toward one of the brightest stars in the night sky. This new information offers more insight into the oldest known man-made structures in North America. PHOTO CREDIT: Eddy Perez, LSU.

A new study shows the LSU Campus Mounds are the oldest known human-made structures in North America.

The study, led by Brooks Ellwood, a professor emeritus of geology and geophysics at LSU, used radiocarbon dating to determine that construction of the first mound, mound “B” began around 11,000 years ago. The mound was constructed, layer by layer, over thousands of years, to about half of its current height, when it was abandoned about 8,200 years ago and remained untouched for another 1,000 years.

“There’s nothing known that is man-made and this old still in existence today in North America, except the mounds,” Ellwood said.”

Around 7,500 years ago, indigenous people began construction on mound “A,” which was built up with mud likely taken from where the entrance to Tiger Stadium sits today.

Geologists think indigenous people finished mound “B” before mound “A,” completing both around 6,000 years ago.

The scientists took sediment cores from the two mounds, which revealed layers of ash from burned reed and cane plants, as well as burned bone fragment, likely indicating the mounds were used for a ceremonial purpose. Brooks also believes the mounds were built to align with Arcturus, one of the brightest stars that can be seen from Earth.

Ellwood’s study was published in the in the American Journal of Science by Yale University.


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Piper Hutchinson
Piper Hutchinson

Piper Hutchinson is a reporter for the Louisiana Illuminator. She has covered the Legislature and state government extensively for the LSU Manship News Service and The Reveille, where she was named editor in chief for summer 2022.