02534nas a2200289   4500000000100000000000100001008004100002260002900043100002000072700001800092700001800110700001900128700001700147700001900164700001500183700001700198700001900215700001600234700002100250700001300271245015800284856005500442300001200497490000700509520171400516020001402230       2010                            d  bBlackwell Publishing Ltd1 aAnna Haapaniemi1 aJames Scourse1 aVictoria Peck1 aHilary Kennedy1 aPaul Kennedy1 aSidney Hemming1 aMark Furze1 aAnna nKowski1 aWilliam Austin1 aJohn Walden1 aEmilie Wadsworth1 aIan Hall00aSource, timing, frequency and flux of ice-rafted detritus to the Northeast Atlantic margin, 30\textendash12 ka: testing the Heinrich precursor hypothesis  uhttp://dx.doi.org/10.1111/j.1502-3885.2010.00141.x  a576-5910 v393 aIncreased fluxes of ice-rafted detritus (IRD) from European ice sheets have been documented some 1000\textendash1500 years before the arrival of Laurentide Ice Sheet (LIS)-sourced IRD during Heinrich (H) events. These early fluxes have become known as \textquoteleftprecursor events\textquoteright, and it has been suggested that they have mechanistic significance in the propagation of H events. Here we present a re-analysis of one of the main cores used to generate the precursor concept, OMEX-2K from the Goban Spur covering the last 30 ka, in order to identify whether the British\textendashIrish Ice Sheet (BIIS) IRD fluxes occur only as precursors before H layers. IRD characterization and planktonic foraminiferal δ18O measurements constrained by a new age model have enabled the generation of a continuous record of IRD sources, timing, frequency and flux, and of local contemporary hydrographic conditions. The evidence indicates that BIIS IRD precursors are not uniquely, or mechanistically, linked to H events, but are part of the pervasive millennial-scale cyclicity. Our results support an LIS source for the IRD comprising H layers, but the ambient glacial sections are dominated by assemblages typical of the Irish Sea Ice Stream. Light isotope excursions associated with H events are interpreted as resulting from the melting of the BIIS, with ice-sheet destabilization attributed to eustatic jumps generated by LIS discharge during H events. This positive-feedback mechanism probably caused similar responses in all circum-Atlantic ice-sheet margins, and the resulting gross freshwater flux contributed to the perturbation of the Atlantic Meridional Overturning Circulation during H events.  a1502-3885