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.

中文翻译：

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探索冰筏碎片的波动在多大程度上反映了源冰盖的质量变化：使用最后一个英国-爱尔兰冰盖的模型观测比较

英国和爱尔兰冰盖（BIIS）在第四纪晚期具有很强的动态性，其变化的时间和程度存在相当大的区域差异。这反映在同样多变的海上冰筏碎片 (IRD) 记录中。在这里，我们使用 FRUGAL 中间复杂性冰山 - 气候模型对这两个记录进行协调，并使用不同的 BIIS 集水区冰山通量，以模拟最后一个高度期间沿西欧边缘 1000 年时间步长的 IRD 起源和幅度的变化。 BIIS 冰川作用（31-6 ka  bp）。将此模拟的 IRD 变异性与沿该边缘的五个岩心的深海现有 IRD 记录进行比较。在此期间，观测值和模型之间的时间和空间 IRD 变异性普遍一致。爱尔兰西北部的豪猪银行被模型确认为拥有近海 IRD 的完全北部或南部源区的地点之间的主要分界线。在海因里希事件 1 和 2 期间，核心显示出一部分北美 IRD，尤其是不列颠群岛南部的证据。建模支持这种可能的海因里希影响的南方偏差，但也表明北美 IRD 只会在异常情况下达到英国边缘。