PEDOLOGY, SEDIMENTOLOGY, AND GEOMORPHOLOGY OF ICE WALLED LAKE PLAINS AND ASSOCIATED SUPERIMPOSED LANDFORMS IN NORTHERN ILLINOIS

More than 2000 Ice Walled Lake Plains (IWLP) have been mapped in Illinois. Many of the larger IWLP have superimposed landforms (SIL) which occur as elevated circular rims with interior depressions. The origin of these superimposed landforms has not been studied in detail. The pedologic, sedimentologic and geomorphic characteristics of IWLP and associated SIL were investigated. Morphometric properties of 66 superimposed landforms were performed using ArcGIS, and compared to possible moderrn glacial and periglacial analogs. We interpreted the superimposed landforms to be relict pingos that formed as permafrost aggraded into drained Ice Walled Lakes. This supports the existence of past permafrost in the study area, and can be used to aid in paleo-climatic reconstructions. Soil geomorphic relationships changed systematically across IWLPs and superimposed landforms.