North-Central Section (36th) and Southeastern Section (51st), GSA Joint Annual Meeting (April 3–5, 2002)

Meltwater discharge from each glacial advance leaves its imprint on the landscape as complex systems of abandoned channels, misfit streams, and master streams. Because of the relatively high elevations of the Glaciated Allegheny Plateau in northeastern Ohio and its generally thin mantle of glacial sediments, many interglacial or interstadial streams, originating as meltwater streams, had the potential to incise bedrock. Ice and deposits of the next glacial event may bury these bedrock valleys, and drainage at the end of this event may have not necessarily followed the previous "preglacial" drainage system. Repetitions of this scenario lead to a complex system of subparallel or crosscutting buried valleys that cannot be integrated into a plausible drainage net.

On the Allegheny Plateau DEMs show that glaciation has imparted a topographic grain to the landscape by streamlining resistant bedrock highs and eroding intervening lowlands underlain by shale. Outwash streams exhumed some buried valleys that were parallel to glacial flow whereas other valleys, transverse to flow, remained buried. Modern and some buried transverse valleys appear to have originated as ice marginal streams. Buried valleys, containing < 70 m of fill, are considered shallow; those, having > 70 m and as much as 200 m, of fill are classified as deep. The shallow valleys are related to more recent glaciations and may contain extensive outwash deposits. Deeper valleys may be preglacial or Early Pleistocene in age and may have glacially-modified upper cross sections. Well logs and seismic records show that many of the deeper valleys are filled with lacustrine sediments, suggesting that southward-flowing ice dammed their downstream channel segments. The Pleistocene geology of the interlobate area among the Killbuck, Cuyahoga, and Grand River lobes in northeastern Ohio illustrates the complexity of the meltwater drainage and the formation of buried valleys.