TY - JOUR

T1 - Formational history of the Wicklow Trough: a marine transgressed tunnel valley revealing ice flow velocity and retreat rates for the largest ice stream draining the late-Devensian British-Irish Ice Sheet.

AU - Coughlan, Mark

AU - Tóth, Zsuzsanna

AU - Van Landeghem, Katrien

AU - McCarron, Stephen

AU - Wheeler, Andrew J.

N1 - Marine Institute Science Foundation Ireland. Grant Number: 13/RC/2092

PY - 2020/10

Y1 - 2020/10

N2 - The Wicklow Trough is one of several Irish Sea bathymetric deeps, yet unusually isolated from the main depression, the Western Trough. Its formation has been described as proglacial or subglacial, linked to the Irish Sea Ice Stream (ISIS) during the Last Glacial Maximum. The evolution of Wicklow Trough and neighbouring deeps, therefore, help understand ISIS dynamics, when it was the main ice stream draining the former British-Irish Ice Sheet. The morphology and sub-seabed stratigraphy of the 18 km long and 2 km wide Wicklow Trough is described here from new multibeam echosounder data, 60 km of sparker seismic profiles and five sediment cores. At a maximum water depth of 82 m, the deep consists of four overdeepened sections. The heterogeneous glacial sediments in the Trough overlay bedrock, with indications of flank mass-wasting and subglacial bedforms on its floor. The evidence strongly suggests Wicklow Trough is a tunnel valley formed by time transgressive erosional processes, with pressurised meltwater as the dominant agent during gradual or slow ice sheet retreat. Its location may be fault controlled, and the northern end of the Wicklow Trough could mark a transition from rapid to slow grounded ice margin retreat, which could be tested with modelling.

AB - The Wicklow Trough is one of several Irish Sea bathymetric deeps, yet unusually isolated from the main depression, the Western Trough. Its formation has been described as proglacial or subglacial, linked to the Irish Sea Ice Stream (ISIS) during the Last Glacial Maximum. The evolution of Wicklow Trough and neighbouring deeps, therefore, help understand ISIS dynamics, when it was the main ice stream draining the former British-Irish Ice Sheet. The morphology and sub-seabed stratigraphy of the 18 km long and 2 km wide Wicklow Trough is described here from new multibeam echosounder data, 60 km of sparker seismic profiles and five sediment cores. At a maximum water depth of 82 m, the deep consists of four overdeepened sections. The heterogeneous glacial sediments in the Trough overlay bedrock, with indications of flank mass-wasting and subglacial bedforms on its floor. The evidence strongly suggests Wicklow Trough is a tunnel valley formed by time transgressive erosional processes, with pressurised meltwater as the dominant agent during gradual or slow ice sheet retreat. Its location may be fault controlled, and the northern end of the Wicklow Trough could mark a transition from rapid to slow grounded ice margin retreat, which could be tested with modelling.

KW - Wicklow Trough

KW - Irish Sea

KW - tunnel valley

KW - glacial processes

KW - Irish Sea Ice Stream

U2 - 10.1002/jqs.3234

DO - 10.1002/jqs.3234

M3 - Article

VL - 35

SP - 907

EP - 919

JO - Journal of Quaternary Science

JF - Journal of Quaternary Science

SN - 1099-1417

IS - 7

ER -