Thrust faulting in glaciers? Re?examination of debris bands near the margin of Storglaciären, Sweden

Thrust faulting has been suggested as a viable mechanism of debris transport at many glaciers, often inferred from the presence up-glacier dipping bands that emerge ice surface to form ridges basally derived material. However, modelling indicates development thrust faults is mechanically inhibited because stresses are much lower than required for shear failure, prerequisite faulting, and field measurements fail detect thrust-related displacement. The emplacement these appear polythermal valley glacier termini remains open question. This study re-examines origin on Storglaciaren, in northern Sweden, using observations, microstructural analyses, sediment grain size analysis, stable isotope composition ice, modelling. We find no evidence discrete displacement across produce ridges, nor do we folding might be responsible. propose originate base by one two mechanisms, perhaps combination: (i) refreezing meltwater near thermal transition basal (ii) injection into tensile fractures periodically opened due high fluid pressure then freezing. In either case, separation occurs freezing introduces below bands, which transported forwards upwards longitudinal compression, revealed ablation.