The formation of a rectilinear ridge network, Múlajökull, Iceland

Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet

“…The low to moderate clast fabrics with generally steeply dipping clasts, both down‐ and upglacier (Figure 9b), resemble both macro and micro fabric measurements described from CSRs at modern surge‐type glaciers in Iceland (Bjarnadóttir, 2007; Gadd, 2016; Sharp, 1985) and elsewhere at beds of past ice streams (Ankerstjerne et al, 2015; Evans et al, 2020; Lamsters et al, 2021), which indicate the intrusion of till into basal crevasses. The upglacier dipping clast rich layer and silt layer in section B2 and B3 in Bakkaflói are further indicative of the upward flow of till.…”

“…The orientation of the clast fabrics predominantly oblique to the general ice flow direction in the area, in both directions (Figure 9b) is difficult to explain but might reflect the complex flow of till upwards and obliquely into the crevasses. Additionally, this could be influenced by subsequent shearing during post‐depositional transport prior to ice stagnation (Ankerstjerne et al, 2015; Gadd, 2016). However, it should be mentioned that the post‐glacial degradation of the CSRs (Figure 9a), as previously explained, might affect the clast fabric after its formation, especially on the flanks of the ridges.…”

“…The orientation of the clast fabrics predominantly oblique to the general ice flow direction in the area, in both directions (Figure 9b) is difficult to explain but might reflect the complex flow of till upwards and obliquely into the crevasses. Additionally, this could be influenced by subsequent shearing during post-depositional transport prior to ice stagnation (Ankerstjerne et al, 2015;Gadd, 2016).…”