As glaciers modify the landscape the conditions upon which they operate (flow) can change for example glaciers may be flowing over loose sediment as they advance and may transition onto a bedrock surface absent of soils. The amount of subglacial water at the base of a glacier also vary in the above example and in soils subglacial meltwater may infiltrate into permeable soils where it may not be able to on solid bedrock, hence subglacial conditions can change over broad areas and distances along a glacier flow path. Accordingly as conditions change patterns of deposition and erosion by the glacier may change with the result that groups of landforms reflecting those conditions may appear that are characteristic of subglacial, ice marginal or proglacial settings. The patterns of landforms and deposits that result are known as landsystems. In New York and many locations around the Great Lakes scientists can compare the sediments left by glaciers in combination with the landforms (sediment-landform assemblage) and try to reconstruct the glacial conditions. Further scientists can compare the ancient landscape to landscapes that are emerging from modern glacial environments.
Kozlowski, A.L.; Graham, B.L. (Eds), June 2014, Glacial Geology of Cayuga County of the Eastern Finger Lakes: Lakes, Lore and Landforms; Guidebook for the 77th annual Reunion of the Northeastern Friends of the Pleistocene Meeting, Auburn, NY 140 pp.
Kehew, Alan. E.; Kozlowski, A.L.; Brian C. Bird; Esch, J. M., May 2013, Contrasting Terrains of the Lake Michigan and Saginaw Lobes of the Laurentide Ice Sheet in southern Michigan. In Gillespie, Robert (ed.) Insights into the Michigan Basin: Salt deposits, Impact structure, Youngest Basin Bedrock, Glacial Geomorphology, Dune Complexes, and Coastal Bluff Stability. Geological Society of America Field Trip Guide 31 pp15-36,
Kehew, Alan. E., Esch, J. M., Kozlowski, A. L. and Ewald, S. K. 2011, Glacial landsystems and dynamics of the Saginaw Lobe of the Laurentide Ice Sheet, Michigan , USA, Quaternary International, Vol. 24, no. 22, pp.1-11
Kehew, A.E., Lord, M.L., and Kozlowski, A.L. 2007 Glacifluvial landforms of erosion. In: Elias, S.A. (Ed.), Encyclopedia of Quaternary Science. Elsevier, p.818-830.
Kehew, Alan. E., Beukema, S. P., Bird, B. C. and Kozlowski, A. L. 2005, Fast flow/surge dynamics of the Lake Michigan Lobe: evidence from sediment-landform assemblages in southwestern Michigan, USA Quaternary Science Reviews, Vol. 24, no. 22, 2335-2353