The related study has been published as: Zhang, Y., Sachau, T., Franke, S., Yang, H., Li, D., Weikusat, I., & Bons, P. D. (2024). Formation mechanisms of large-scale folding in Greenland's ice sheet. Geophysical Research Letters, 51(16), e2024GL109492. https://doi.org/10.1029/2024GL109492
Airborne radio‐echo sounding (RES) data reveal internal ice layering and large‐scale folding (up to >100 m, sometimes even 1 km fold amplitude) in several regions of Greenland's ice sheet. However, there is no consensus yet on how these folds form.
Here we use the full-Stokes code Underworld2 to simulate ice movements in three-dimensional convergent flow, mainly concerning ice anisotropy due to crystallographic preferred orientation (CPO), vertical viscosity and density contrasts in ice layers, and bedrock topography.
Model 1: isotropic ice, free-slip basal boundary
Model 2: anisotropic ice, free slip
Model 3: anisotropy, flat bedrock surface
Model 4: anisotropy, bumpy bedrock surface (max 400m)
Model 5: isotropy, bumpy bedrock surface (max 400m)
Model 6: anisotropy, bumpy bedrock surface (max 400m), softness in ice viscosities
Model 7: isotropy, bumpy bedrock surface (max 400m), softness in ice viscosities
Model 8: larger along-flow model size based on Model 4
Model 9: smaller bumps based on Model 4
Model 10: larger bumps based on Model 4
Model 11: larger anisotropy based on Model 4
Model 12: with ice precipitation based on Model 11
Model 13: pre-existed folds (300 m), flat bedrock surface, anisotropy
Model 14: pre-existed folds (300 m), flat bedrock surface, anisotropy
Model 15: pre-existed folds (300 m), flat bedrock surface, isotropy