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Lookup NU author(s): Dr Matthew Burke, Dr Louise Callard
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2022 The Authors. Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium. The BRITICE-CHRONO consortium of researchers undertook a dating programme to constrain the timing of advance, maximum extent and retreat of the British–Irish Ice Sheet between 31 000 and 15 000 years before present. The dating campaign across Ireland and Britain and their continental shelves, and across the North Sea included 1500 days of field investigation yielding 18 000 km of marine geophysical data, 377 cores of sea floor sediments, and geomorphological and stratigraphical information at 121 sites on land; generating 690 new geochronometric ages. These findings are reported in 28 publications including synthesis into eight transect reconstructions. Here we build ice sheet-wide reconstructions consistent with these findings and using retreat patterns and dates for the inter-transect areas. Two reconstructions are presented, a wholly empirical version and a version that combines modelling with the new empirical evidence. Palaeoglaciological maps of ice extent, thickness, velocity, and flow geometry at thousand-year timesteps are presented. The maximum ice volume of 1.8 m sea level equivalent occurred at 23 ka. A larger extent than previously defined is found and widespread advance of ice to the continental shelf break is confirmed during the last glacial. Asynchrony occurred in the timing of maximum extent and onset of retreat, ranging from 30 to 22 ka. The tipping point of deglaciation at 22 ka was triggered by ice stream retreat and saddle collapses. Analysis of retreat rates leads us to accept our hypothesis that the marine-influenced sectors collapsed rapidly. First order controls on ice-sheet demise were glacio-isostatic loading triggering retreat of marine sectors, aided by glaciological instabilities and then climate warming finished off the smaller, terrestrial ice sheet. Overprinted on this signal were second order controls arising from variations in trough topographies and with sector-scale ice geometric readjustments arising from dispositions in the geography of the landscape. These second order controls produced a stepped deglaciation. The retreat of the British–Irish Ice Sheet is now the world’s most well-constrained and a valuable data-rich environment for improving ice-sheet modelling.
Author(s): Clark CD, Ely JC, Hindmarsh RCA, Bradley S, Igneczi A, Fabel D, O Cofaigh C, Chiverrell RC, Scourse J, Benetti S, Bradwell T, Evans DJA, Roberts DH, Burke M, Callard SL, Medialdea A, Saher M, Small D, Smedley RK, Gasson E, Gregoire L, Gandy N, Hughes ALC, Ballantyne C, Bateman MD, Bigg GR, Doole J, Dove D, Duller GAT, Jenkins GTH, Livingstone SL, McCarron S, Moreton S, Pollard D, Praeg D, Sejrup HP, Van Landeghem KJJ, Wilson P
Publication type: Article
Publication status: Published
Journal: Boreas
Year: 2022
Volume: 51
Issue: 4
Pages: 699-758
Print publication date: 01/10/2022
Online publication date: 07/09/2022
Acceptance date: 17/05/2022
Date deposited: 13/10/2022
ISSN (print): 0300-9483
ISSN (electronic): 1502-3885
Publisher: John Wiley and Sons Inc.
URL: https://doi.org/10.1111/bor.12594
DOI: 10.1111/bor.12594
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