The origin of the western Lake Erie grooves, Ohio: implications for reconstructing the subglacial hydrology of the Great Lakes sector of the Laurentide Ice Sheet

Streamlined grooves and s-forms cover the western Lake Erie Islands, Ohio, as well as the channels between the islands, and the adjacent mainland. Although previous interpretations advocate direct glacial ice erosion, we offer the alternative interpretation that forms were eroded by meltwater, specifically by plucking, sediment abrasion, and cavitation in high velocity, sediment-laden flows. We base our arguments on detailed descriptions and interpretations of the Glacial Grooves State Memorial site (GGSM) on Kelleys Island. The site consists of a linear furrow that is adorned by s-forms in its base and on its walls. These include linear forms, cavettos, sichelwannen, comma forms, multi-troughed forms, and plunging forms. All s-form sites provide a snapshot of the last phase of erosion after evolution of the local landscape through multiple generations of s-form formation. As s-forms are found on topographic highs and lows, we believe they represent a regional flow that overtopped the majority of the islands. Flow was initially as a sheet that quickly collapsed into channelized flow that was diverged around the islands. We also believe that this flow had a major impact on the Laurentide Ice Sheet in this region, resulting in rapid glacial advance and extremely low ice-sheet profiles.