The remains of the civilization are found outside of St. Louis Missouri.
The study found that the massive floods of the Mississippi River had led to the downfall of the city and is the major reason for it being abandoned.
The flood occurred somewhere around the beginning of the 13th century.
Researchers have analyzed the sediment of nearby Horseshoe Lake and they found that floods occurred in the region.
Core samples taken as far as 18 feet from the lakebed show evidence of fine and silky bands in the sediments; this led the researchers to confirm that such type of sediment is brought by floods in Horseshoe Lake.
The team has collected the sediments from 125 miles downstream and compared it; they found the same flood signature.
Thus it confirms that several floods occurred in the region and researchers believe that 8 floods occurred between the period 280 and 1800.
The finding of the study reveals that flood is the major reason why the city was abandoned, but researchers cautioned jumping to any conclusion.
Researchers say that there is no way to say any certainty that the flood led to the decline of the Cahokia city.
Researchers are only certain that there’s correspondence in time. Correlation is not evidence of causation without further evidence.
According to Larry Benson, from the University of Colorado Natural History Museum, flood is not the only reason for the destruction of Cahokia, droughts might also have played a role in the devastation of the civilization, though flood could have forced the settlement to shift to higher ground where they can rely on rainfall for agriculture.
Samuel Munoz, a geographer form the University of Wisconsin-Madison and who led the team said: “Rarely do you get such fortuitous opportunities where you have these nice sedimentary records next to an archaeological site that’s so well studied.”
“We hope archaeologists can start integrating these flood records into their ideas of what happened at Cahokia and check for evidence of flooding.”