TY - JOUR

T1 - Formation of crevasse-squeeze ridges at Trygghamna, Svalbard

AU - Ben-Yehoshua, Daniel

AU - Aradóttir, Nína

AU - Farnsworth, Wesley R.

AU - Benediktsson, Ívar Örn

AU - Ingólfsson, Ólafur

N1 - Publisher Copyright: © 2023 John Wiley & Sons Ltd.

PY - 2023

Y1 - 2023

N2 - Crevasse-squeeze ridges (CSRs) are landforms that have been unequivocally linked to surge-type glaciers. The formation of CSRs has been discussed since they were first defined in the mid-1980s. Here, we describe geometric CSR networks from the terrestrial glacier forefields of two glaciers in Trygghamna, Western Svalbard. No glacier surges have been observed in Trygghamna; however, the presence of the CSRs signifies past surge activity. Detailed geomorphological maps were constructed, and the spatial context of these landforms described. Cross-sections of several CSRs highlight ridge architecture, structure and relationships to surrounding landforms and sediments. Most CSRs are symmetrical in cross-profile, orientated perpendicular or oblique to the ice-flow direction. Like previous investigations, we observe these ridge networks on top of till and flutes. Additionally, we, for the first time, document CSRs deposited directly on non-glaciogenic subsurfaces, namely, beach gravels and bedrock. Our findings confirm previous CSR formation theories; basal sediments are squeezed into bottom-up crevasses during surges, which are subsequently transported englacially until surge termination and are finally released by melt out from stagnant ice. Consequently, a network of CSRs is the product of a significant reorganisation and down-glacier transport of basal sediment, exemplifying how single surges are agents of glacial sediment redistribution. These formation processes are illustrated in a refined schematic model. The results further contemporary understanding of CSRs in terrestrial surge-type glacier settings and may also apply to landforms and sediments in certain marine settings and palaeoglacial environments.

AB - Crevasse-squeeze ridges (CSRs) are landforms that have been unequivocally linked to surge-type glaciers. The formation of CSRs has been discussed since they were first defined in the mid-1980s. Here, we describe geometric CSR networks from the terrestrial glacier forefields of two glaciers in Trygghamna, Western Svalbard. No glacier surges have been observed in Trygghamna; however, the presence of the CSRs signifies past surge activity. Detailed geomorphological maps were constructed, and the spatial context of these landforms described. Cross-sections of several CSRs highlight ridge architecture, structure and relationships to surrounding landforms and sediments. Most CSRs are symmetrical in cross-profile, orientated perpendicular or oblique to the ice-flow direction. Like previous investigations, we observe these ridge networks on top of till and flutes. Additionally, we, for the first time, document CSRs deposited directly on non-glaciogenic subsurfaces, namely, beach gravels and bedrock. Our findings confirm previous CSR formation theories; basal sediments are squeezed into bottom-up crevasses during surges, which are subsequently transported englacially until surge termination and are finally released by melt out from stagnant ice. Consequently, a network of CSRs is the product of a significant reorganisation and down-glacier transport of basal sediment, exemplifying how single surges are agents of glacial sediment redistribution. These formation processes are illustrated in a refined schematic model. The results further contemporary understanding of CSRs in terrestrial surge-type glacier settings and may also apply to landforms and sediments in certain marine settings and palaeoglacial environments.

KW - crevasse fill ridges

KW - crevasse-squeeze ridges

KW - glacier retreat

KW - landform formation

KW - ridge networks

KW - subglacial processes

KW - surging glacier

KW - Svalbard

U2 - 10.1002/esp.5631

DO - 10.1002/esp.5631

M3 - Journal article

AN - SCOPUS:85161303644

VL - 48

SP - 2334

EP - 2348

JO - Earth Surface Processes and Landforms

JF - Earth Surface Processes and Landforms

SN - 0197-9337

IS - 12

ER -