That's definitely beyond me, but similar types of observations of strong ice-bed coupling with displacement/deformation occurring deep ( >2 m) within the substrate have been made in-situ (Truffer et al. 2000, and references within), and interpreted from landform-sediment associations in front of modern (Kjaer et al., 2006) and older Pleistocene examples (Vaughan-Hirsch et al., 2013; Phillips et al., 2017).

these might be relevant for helping to interpret your modelling results. Another type of landform that might be somewhat analagous would be hill-hole pairs(?)

Cheers and bonne chance!

Riley

Kjær, K. H., Larsen, E., van der Meer, J., Ingólfsson, Ó., Krüger, J., Benediktsson, Í. Ö., ... & Schomacker, A. (2006). Subglacial decoupling at the sediment/bedrock interface: a new mechanism for rapid flowing ice. Quaternary Science Reviews, 25(21-22), 2704-2712.

Phillips, E., Evans, D. J., Atkinson, N., & Kendall, A. (2017). Structural architecture and glacitectonic evolution of the Mud Buttes cupola hill complex, southern Alberta, Canada. Quaternary Science Reviews, 164, 110-139.

Truffer, M., Harrison, W. D., & Echelmeyer, K. A. (2000). Glacier motion dominated by processes deep in underlying till. Journal of Glaciology, 46(153), 213-221.

Vaughan‐Hirsch, D. P., Phillips, E., Lee, J. R., & Hart, J. K. (2013). Micromorphological analysis of poly‐phase deformation associated with the transport and emplacement of glaciotectonic rafts at W est Runton, north Norfolk, UK. Boreas, 42(2), 376-394.

Hi Riley,

Many thanks for your answer, I appreciate your paper recommendations...Most of these papers mainly describe glacitectonics that occur at the glacier margin however...I still did not find any evidence of obstacle, ridge or moraine pushed and displaced subglacially in the literrature (not a very accessible environment I will say :) ).

Cheers.

Edouard

We have discovered subglacial landforms for which we know not the genesis. But your ‘terraces on the back’ struck me as similar to the shingled pattern we see. Gustaf Peterson in Journal of Maps (2017) shows these (V-forms) but especially Mäkinen et al (2017), QSR (triangular forms). The genesis is not clear, but sunglacial shearing is a potential process.

Hi Mark,

Thanks for the reference. We do reproduce structures similar to those observed in Peterson (2017). No triangular-shaped subglacial landforms though...

Cheers,

Edouard

I have interpreted some glacial landforms in such a way, but mostly from the point of possible subglacial glaciotectonic or deformational erosion: Landform classification: "Five types of mostly erosional glaciotectonic landforms were recognized: (1) plucked lee side, (2) hill-hole pair, (3) fanlike and transverse edges of plucked depressions, (4) sporadic plucked hollows, and (5) deformational or glaciotectonic mound or ridge." ( Matti V. J. Seppälä, 2016.  Lidar-Based Detection and Interpretation of Glaciotectonic Features of the Morainic Topography of Finland.Article Lidar-Based Detection and Interpretation of Glaciotectonic F...

Dear Matti,

Thanks for the paper. We can recognize some features you mapped in Finland we reproduced experimentally.

Cheers,

Edouard

Dear Edouard,

You should look several papers related to ribbed moraine formation. Those transversal ridges have formed subglacially relatively far from the ice margin in the contact zone of cold and warm bed glacier. See for example Sarala, P., 2006. Ribbed moraine stratigraphy and formation in southern Finnish Lapland. Journal of Quaternary Science 21:4, 387-398 and references in it.

Regards,

Pertti Sarala