ESLARP East St. Louis Action Research Project
University of Illinois at Urbana-Champaign

History of East St. Louis

Prehistoric East St. Louis

East St. Louis is located in the northern half a broad lens-shaped alluvial flood plain of the Mississippi River known as the American Bottoms. Although this flood plain appears to be very uniform, the physiography is actually a mosaic of six distinctive regions. The history of its physical formation is described in four eras; because of the time scale the dates are estimates.

Formative Eras

600M BC to 200M BC - Following a long period of igneous activity, the Mississippi Valley area was covered by shallow seas advancing and retreating in response to crustal movements in the Appalachian and Ozark areas. The advance and retreat of the seas was alternately accompanied by marine deposition and erosion. This cycle formed the base of the area by produced over 3,500 feet of limestone, shale, and coal. In about 280M BC the seas retreated for the last time and the area became land, constantly exposed to the forces of erosion. Additional movements within the earth's crust caused the land to tilt, dropping mainly towards the east and bending north-south around the Bottoms area.

200M BC to 1M BC - The watercourse that would become the Mississippi began to move through the area. The force of the water removed most of the softer materials (shale and coal) and cut into the harder limestone beneath. This period of erosion created a valley similar in width but deeper than today's Mississippi. The widening of the valley in the area that became the American Bottoms was a result of differences in the elevations at which the softer materials existed.

1M BC to 75,000 BC (The Ice Age)- This period included four major glaciations. It is not clear whether the first two had any impact on the formation of the Bottoms. However, there is observable evidence that the third glacier, the Illinoian, covered the area. Evidence includes the presence of large boulders on the bedrock surface of the valley, the deposition of some unsorted and sorted material on the uplands, and the creation of Sangamon soils, also on the uplands. The fourth glacier, the Wisconsinan, stopped 75 miles north of the area but still had a significant impact on the present terrain. The valley became a major drainage way for the sediment-laden meltwaters. The huge volume of material widened the Bottoms even further and filled the valley with glacial material to a depth of at least 150 feet. Some of this material was picked up by wind during non-flood periods and deposited along the eastern boundary of the Bottoms. In places adjacent to the Bottoms flood plain this loess material attained a depth of 50 feet, gradually lessening further east.

75,000 BC to 12,000 BC - The final glacier melted, the accompanying material deposits decreased, and the erosive forces of the Mississippi River increased. The River removed nearly 50 feet of meltwater-deposited materials from the broad flood plain of the Bottoms but left behind nearly 100 feet of material which was formed into various patterns of land and water.




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
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