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GeologyOfWatershed


Sour Grapes and Saddle Sores
George Hirst

Geology of a Watershed
February 3, 2005

I believe it is important that people who live in an area know the story of the land about them. We need to remember that we are here not by our worth, but by privilege. We are renters, not owners. We need to know how the space we occupy came to be, how it is being used, and what the future holds. What follows is the "story" of Western Stark County as it came to be the land we "rent".

The western part of Stark County received glacial deposits of the Illinoian age beginning about 300,000 years ago and ending about 125,000 years ago. The Illinoian glacier reached the Mississippi River and went south nearly to the tip of Illinois as it approached from the northeast from centers in Canada.

The long interglacial age that occurred before the Wisconsin glacier approached from the east 75,000 years ago, is known as the Sangamon Interglacial period. In this period highly weathered soils formed in the Radnor till deposit, spent 50,000 years in a climate warmer than at present. Later, the glacial till was buried by wind deposited silt (called Loess)blown in from the Mississippi & Illinois River Valleys. The buried soils are called paleosols. Most of our modern day soils are formed in the upper 5 feet of loess in western Stark county and are not older than 25,000 years.

In western Stark County, on slopes where the loess thins, due to both present day erosion and past geologic erosion, modern day soils are formed in both loess and paleosols .

The present day appearance is the result of floods of water, released from melting ice to the east, from the approaching Wisconsin glacier, which dug new drainageways and deepened old ones. The Spoon River is a major example in Stark County. It was a major drainage way for melt waters off of the Wisconsin glacier. Indian Creek near Toulon and Walnut Creek were deepened.

Western Stark county's distinctive topography, broad flat uplands, is characterized by the dissection of many small creeks and numerous narrow streams in steep-walled valleys. The drainage network is extensive and well developed as compared to the appearance of eastern Stark County, where the landscape is gently rolling.

Walnut Creek along West Jersey Blacktop, where the creek intersects the road twice in a 2 mile distance after leaving West Jersey, is an example of this mature landscape. There are several islands of uplands out in the bottomland in this area. These are remnants in the floodplain left as the stream meandered back and forth across the landscape.

As one travels across this part of the county looking at the fields, one sees the results of melting glaciers and wind. The landscape is also due to what farmers have done, and are doing with the land. Columns succeeding this one will tell you about the people at work, using and protecting the land.

A thank you to Steve Zwicker, Princeton, Soil Scientist for the USDA, Natural Resources Conservation Service.

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Created by KKris. Last Modification: Friday 01 of August, 2008 21:07:34 UTC by KKris.