Free Republic

One thousand years ago, on a floodplain of the Mississippi River near modern-day St. Louis, the massive Native American city known today as Cahokia sprang suddenly into existence. Three hundred years later it was virtually deserted... While analyzing cores from Horseshoe Lake, an oxbow lake that separated from the Mississippi River some 1,700 years ago, Munoz's team discovered a layer of silty clay 19 centimeters (7.5 inches) thick deposited by a massive ancient flood. It's unlikely that the ancient floodwaters were high enough to inundate the ten-story mound at Cahokia's center, a structure now called Monk's Mound... But a flood...

Lake Sediments Record Climate Change At Cahokia INDIANAPOLIS, INDIANA —National Public Radio reports that climatologist Broxton Bird of Indiana University-Purdue University Indianapolis and colleagues analyzed layers of calcite crystals interspersed with layers of mud on the bottom of Indiana’s Martin Lake in order to learn about historic rainfall levels at Cahokia. The study suggests that beginning in the 900s, the Central Mississippi Valley received more rain than usual. And carbon isotopes found in skeletons at Mississippian cities indicate that people ate a lot of corn. “That comes at right around 950, and that’s around the time the population at Cahokia...