An early epiphany was that ice margins in Vermont were not simple, like lines on a map as conventionally regarded, mapped, and drawn using the layer cake model. Instead, ice margins are identified as wide, complex zones, including features formed at both active and stagnant ice margins, having overlapping temporal and spatial relationships, and confronted by increasing volumes of meltwater, in close association with standing proglacial waters. Ice margins are characterized, for example as active, stagnant, hybrid (which include both stagnant and active ice), step-down, destabilized, calving, disaggregated, diachronic, oscillatory versus readvance types, Warm vs Cold, streaming, calving, and possibly collapsing (?).
This complexity fundamentally reflects Glacial Dynamics. To some extent this was driven by the interation between the ice sheet and proglacial water bodies along the margin. For example, Hu and Hasseloff, 2025, 1 Hu, K. and Hasseloff, M. 2025, Proglacial Lake Drainage Events Drive Fast Grounding Line Advance in a Warming Climate; Geophysical Research Letters; https://doi.org/10.1029/2025GL115184 in their Abstract state:
“Proglacial lakes along the retreating margin of the Laurentide ice sheet (LIS) significantly influenced the ice sheet’s dynamics. This study investigates the interaction between proglacial lake drainage events and ice sheet evolution during deglaciation. Using a flowline ice sheet model, we demonstrate that abrupt lake drainage caused by the opening of spillways during the retreat of the ice sheet can temporarily reverse ice retreat and trigger rapid grounding line advance despite ongoing climate warming. We also show that ice shelf regrounding on a retrograde lake bed can follow lake drainage and further amplify ice sheet advance. These processes can decouple ice dynamics from climate forcing, offering a non-climatic mechanism to explain the observed highly irregular ice margin fluctuations of the LIS. Our findings suggest that proglacial lakes might play an important role in modulating ice sheet evolution in warming climates.”
Similarly, Carrivick et al, 2020, 2 Carrivick, J.L. et al, 2020, Toward Numerical Modeling of Interactions Between Ice-Marginal Proglacial Lakes and Glaciers Front. Earth Sci., 28; https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2020.577068/full likewise identify Glacial Dynamics associated with proglacial lake level fluctuation and ice margins:
“Studies on modern glaciers have shown that when an ice-marginal lake drains, a local portion of the adjacent glacier is near-instantaneously de-buttressed promoting calving.” And further: “This Perspectives paper provides the foundation for future studies aiming to address these problems more thoroughly. Concerted efforts continue by researchers around the World who are applying ice sheet models to ice-marginal lake problems, most especially to reconstructions of the Laurentide Ice Sheet for interest in ice sheet (in)stability and collapse, ice stream development and meltwater pulses. Understanding the last Quaternary (de)glaciation will inform our understanding of the present and future evolution of the Greenland and Antarctic ice sheets. Indeed, we challenge future Greenland and Antarctic ice sheet models to consider lake-glacier interactions.”
Footnotes