|2004 Denver Annual Meeting (November 7–10, 2004)|
|Paper No. 118-4|
|Presentation Time: 1:30 PM-5:30 PM|
THE TICONA CHANNEL, A POSSIBLE SUB-ICE TUNNEL VALLEY
NELSON, Robert S.1, MALONE, D.H.1, MURPHEY, J.L.1, WALLS, T.A.1, WILLEMS, B.A.1, LARSON, T.H.2, and PUGIN, A.J.M.2, (1) Department of Geography-Geology, Illinois State Univ, Normal, IL 61790, firstname.lastname@example.org, (2) Illinois State Geol Survey, Natural Resources Building, 615 East Peabody Drive, Champaign, IL 61820-6964|
The Ticona Channel in north central Illinois is a relatively narrow deep bedrock valley with few recognizable tributaries. In 1940 Bo Willman and again in 1950, Leland Horberg interpreted the channel to be a tributary to the Ancient (preglacial) Mississippi River, joining the Ancient Mississippi River where it changes from flowing southeasterly to southwesterly as it encountered the west flank of the LaSalle Anticlinorium. The age of the channel has remained a question. Was it a preglacial stream or did it originate during one of several glacial advances into Illinois. An interesting observation is that as a preglacial channel it would drain to the west, opposite the regional dip of the anticlinorium and the generally easterly slope of the top of bedrock. Recent high-resolution, shear wave seismic profiles across the channel revealed steep valley walls. The channel is filled with glacial diamicts overlying coarse grainular sediments. A core from a scientific borehole located along one of the seismic lines revealed Wedron (Wisconsin Episode) and Glasford (Illinois Episode) formation tills (total of about one hundred and twenty-five feet) above about seventy-five feet of sand and gravel. It is hypothized that the Ticona Channel originated as a consequent stream draining eastward, down the regional dip. During the Illinois Episode, as ice advanced from the northeast, up the regional gradient and dip, the Ticona Channel was deepened as a sub-ice tunnel valley, and its flow reversed as subglacial water flowed westward into the Ancient Mississippi River Valley.
2004 Denver Annual Meeting (November 7–10, 2004)
General Information for this Meeting
|Session No. 118--Booth# 10|
Colorado Convention Center: Exhibit Hall
1:30 PM-5:30 PM, Monday, 8 November 2004
Geological Society of America Abstracts with Programs, Vol. 36, No. 5, p. 281
© Copyright 2004 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.