RELATIONSHIPS AND PATTERNS OF CHANNEL FORMATION DURING DEGLACIATION OF THE MIAMI LOBE, NEAR PIQUA, OHIO

Forty Paleochannels associated with the Miami lobe of the Laurentide Ice sheet, near Piqua Ohio, were analyzed to determine whether the formation of channels is time-transgressive or results from a single deglaciation event. Analysis focused on relationships of channel gradient and stratigraphy in comparison to temporal distribution. Timing of events is linked to six discontinuous moraines that dissect the study area. Spatial distribution was analyzed using ArcMap, while field data was collected to determine relationships of stratigraphy and distribution. The combined data was organized into a classification scheme based on shape of the channel, sediment type in the channel, and orientation relative to moraines. Channel type A has valley walls with a gradient higher than 0.4, contains stratified sand and gravels, and generally dissects moraines throughout the study area. Channel type B has valley walls with a gradient range from 0.15 to 0.4, generally contains a clay-sand diamict that coarsens downward to sand and pebble dominated diamict, and are oriented both laterally and perpendicular to moraines. Channel type C has valley walls with a gradient less than 0.15, generally contains a clay-rich brown to red diamict that may fine or coarsen downwards, and are dominantly oriented perpendicular to moraines. Type B and C channels represent 75% of the channels described, are spatially bracketed by younger (northern) moraines and generally do not dissect moraines, therefore they represent single glacial events. Type A channels dissect multiple moraines or flow parallel to older (southern) moraine margins and represent time-transgressive formation. Results show that type A channels represent multiple events and reoccupation of channels through deglaciation of the Miami lobe while B and C channels represent single deglaciation events at a particular time.