Exploring the extent to which fluctuations in ice‐rafted debris reflect mass changes in the source ice sheet: a model–observation comparison using the last British–Irish Ice Sheet

Type Article
Acceptance Date 2021 IN PRESS
Language English
Author(s) Wilton David J.1, Bigg Grant R.ORCID2, Scourse James D.ORCID1, Ely Jeremy C.ORCID2, Clark Chris D.ORCID2
Affiliation(s) 1 : Department of Geography, University of Exeter, Penryn Cornwall, UK
2 : Department of Geography , University of Sheffield Sheffield , UK
Source Journal of Quaternary Science (0267-8179) (Wiley) In Press
DOI 10.1002/jqs.3273
Keyword(s) British and Irish Ice Sheet, coupled model, deglaciation, Heinrich event, ice]rafted debris
Abstract

The British and Irish Ice Sheet (BIIS) was highly dynamic during the Late Quaternary, with considerable regional differences in the timing and extent of its change. This was reflected in equally variable offshore ice‐rafted debris (IRD) records. Here we reconcile these two records using the FRUGAL intermediate complexity iceberg–climate model, with varying BIIS catchment‐level iceberg fluxes, to simulate change in IRD origin and magnitude along the western European margin at 1000‐year time steps during the height of the last BIIS glaciation (31–6 ka bp). This modelled IRD variability is compared with existing IRD records from the deep ocean at five cores along this margin. There is general agreement of the temporal and spatial IRD variability between observations and model through this period. The Porcupine Bank off northwestern Ireland was confirmed by the modelling as a major dividing line between sites possessing exclusively northern or southern source regions for offshore IRD. During Heinrich events 1 and 2, the cores show evidence of a proportion of North American IRD, more particularly to the south of the British Isles. Modelling supports this southern bias for likely Heinrich impact, but also suggests North American IRD will only reach the British margin in unusual circumstances.

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How to cite 

Wilton David J., Bigg Grant R., Scourse James D., Ely Jeremy C., Clark Chris D. Exploring the extent to which fluctuations in ice‐rafted debris reflect mass changes in the source ice sheet: a model–observation comparison using the last British–Irish Ice Sheet. Journal of Quaternary Science IN PRESS. Publisher's official version : https://doi.org/10.1002/jqs.3273 , Open Access version : https://archimer.ifremer.fr/doc/00682/79424/