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Is there a pervasive Holocene ice-rafted debris (IRD) signal in the northern North Atlantic? The answer appears to be either no, or it depends on the proxy!

2006; Volume: 14; Issue: 2 Linguagem: Inglês

10.22498/pages.14.2.7

1563-0803

John T. Andrews, Anne Jennings, Matthias Moros, Claude Hillaire‐Marcel, Dennis D. Eberl,

Geophysical Methods and Applications

2004) of opal and of organic carbon were positively correlated with the high organic carbon content of sediments deposited during warm periods (Bølling and Holocene; Fig. 1).We fi nd elevated 231 Pa/ 230 Th and 10 Be/ 230 Th ratios during warm periods as well (Fig. 1), indicating that increased productivity must have contributed to the higher preserved fl uxes of opal and carbon at those times. ConclusionsWhile these results do not rule out changes in the ventilation of intermediate waters, they do provide clear evidence for changes in bio-logical productivity and the export fl ux of biogenic particles.Enhanced productivity during warm events refl ects a shoaling of the nutricline, an increase in upwelling-favorable winds, or some combination thereof.