East St. Louis Action Research Project
University of Illinois at Urbana-Champaign
History of East St. Louis
Original Physiography
Topography
This period marks the end of the significant natural events which worked to form the American Bottoms. The plain has been differentiated into 6 distinctive regions with differing elevation, topography, hydrology, and soil structure. (can we get a map in here somewhere?):
- Ridge & Swale - an undulating surface of long linear high and low areas, along with large, flat, low areas which were once lakes. The resultant soil types were generally fine sandy loam or silt loam in the irregular areas and silty clay in the former lake areas.
- Mitchell Flats - a very level area of little local relief and subsequently poorly drained. The resultant soil type was generally silty clay.
- East St. Louis High - generally flatter and higher than the surrounding ridge and swale topography; included in this region are the Grand Marias Lakes. The resultant soil type was generally silty clay.
- Terrace - a high, sandy remnant of the earlier glacial-produced flood plain. The resultant soil types were generally fine sandy loam or silt loam.
- Alluvial Fan - a receiving area for material washing down from the uplands. The resultant soil type was generally silt loam.
- Dissected Uplands - small, fairly flat hilltops and steep sloped stream channels. The resultant soil type was generally silt loam.
Hydrology
Approximately 1/5 of the entire Bottoms area consisted of marsh environments of relatively minor agricultural value. These marshes were probably formed in extinct channels of the Mississippi River.
10000 BC - Illinois was possibly ten degrees colder than it is today but warmer than it had been during the ice age. Vegetation zone changes followed the retreating ice and warming temperatures. Thus, Southern Illinois was covered by boreal forest while the tundra zone still existed near the ice margins. The specific plants and animals present are thought to be typical of what might be found in norther Canada today, with the exception of prehistoric species which would soon be extinct: the wooly mammoth, mastadon, and ground sloth.
7000 BC - the front of the continental glacier retreated to Canada and any tundra disappeared from the Americas.
6000 BC - the Midwest underwent a general warming, and new vegetative communities emerged. The uplands became prairies and an oak-hickory forest dominated. A continuation in the warming trend was accompanied by a change in forest to an oak-beech composition and a complex intermingling of forest and prairie.
4000 BC - The Hypsothermal period is characterized by a marked warming trend, producing a climate much warmer and drier than today's. This resulted in the contraction of forest zones and expanded areas of prairie; the limited forests changed to the oak-hickory composition found today.
2000 BC - The end of the Hypsothermal period is marked by a cooler but still dry period. With this reversal of the warming trend the prairies contracted and the forests expanded.
500 BC - The climate essentially stabilized, producing vegetative communities that that become the modern forms although their distribution would continue to change as a result of both natural and human disturbances.
Document author(s) : Barb Baugher, Diane Timlin, Mark Child
HTML by : Barb Baugher, Diane Timlin, Mark Child
Last modified: 29 October, 1995
History of East St. Louis
East St. Louis Action Research Project
