LSU mounds. Source: LSU.
New information has been uncovered on the mounds at Louisiana State University with experts calling them the oldest man-made structures in North America.
It was found that both mounds are perfectly aligned towards one of the brightest stars in the sky with charred mammal bone fragments discovered within.
Each mound is roughly six metres in height and archaeologists have managed to date one of them to 11,000 years ago, belonging to an ancient indigenous community that inhabited the area.
It’s believed the LSU mounds were used for ceremonial or cremation purposes as they found layers of ash from burned plants and osteons. They reached their current height over thousands of years as more layers were added.
LSU Department of Geology & Geophysics Professor Emeritus Brooks Ellwood said that research suggests Mound B was abandoned over 8,000 years ago.
“We don’t know why they abandoned the mounds around [that time], but we do know their environment changed suddenly and dramatically, which may have affected many aspects of their daily life,” he said.
However-around this time- there were major changes happening with climate as temperatures plummeted 1.6 degrees on average over a 160-year period.
But Professor Ellwood says around 7,500 years ago the people decided to build another mound which is known to experts as Mound A.
This structure was made out of mud from an area where the university’s sporting stadium currently stands.
One of the fascinating features of these ancient structures is there orientation to a bright star says LSU astronomer and study co-author Geoffrey Clayton.
“The people who constructed the mounds, at about 6,000 years ago, coordinated the structures’ orientation to align with Arcturus, seen in the night sky at that time.
“The red giant star Arcturus would rise about 8.5 degrees east of north in the night sky.”
