REMNANTS FROM A DISTANT PAST

      There has been much in the news about the flooding and devastation in the Midwest US and Canada. It is some irony that the same forces which created the rivers now flooding, is the same force which gave us the extremely fertile soil the Midwest is so famous for.

      10,000 years ago, the Earth was quite a different place than it is today. There were only about 5 million humans on the planet, and a great deal of the planet was covered an ice age known as the Pleistocene Ice Age. Huge ice sheets covered from the north all the way down to New York and London. The Great Lakes were not yet formed, and the Mississippi River was quite different, the upper part being only a small tributary and flowing more along the path of the Missouri River.

      The huge glaciers advance, pushing heaps of earth ahead of it to deposit the rubble, called glacial till, along its southernmost borders. Along with the rubble was some very fertile soil, which, because it was so dry, was blown and spread out for over a thousand miles.

      As the ice sheets began to melt, the water needed somewhere to drain. A large lake formed north of where the Great Lakes are called Lake Agassiz. As ice continued to melt, and the Saint Lawrence Valley was freed, two spillways were formed, and it was at this time that Niagara Falls came into being. It was during this time that the Great Lakes formed also.

      Meanwhile, the Red River in the north was still blocked by ice and Lake Agassiz spread widely over Northwest Minnesota, part of the Dakotas and much of Saskatchewan. Its only outlet then was to the south by way of the Minnesota River, which joined the Mississippi River just south of St. Paul.

     It was toward the end of this ice age that drainage was finally allowed to the north via the Red River and this river easily floods today. 10,000 years ago may seem like a long time, but geologically, it is but a wink of time. At one time the ice sheets covered about 32 percent of the land, they have now receded to about 10 percent.

      A more frightening thought is that scientists estimate that a drop in average temperature of 41 F would  make the ice sheets return! And on the other hand, a few degrees rise in temperature would cause additional melting which would raise sea level rise a hundred feet!