Holocene ice-rafting and sediment transport from the glaciated margin of East Greenland (67-70 degrees N) to the N Iceland shelves: detecting and modelling changing sediment sources

Type Article
Date 2014-05-01
Language English
Author(s) Andrews John T.1, 2, Bigg Grant R.3, Wilton David J.3
Affiliation(s) 1 : Univ Colorado, INSTAAR, Boulder, CO 80309 USA.
2 : Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA.
3 : Univ Sheffield, Dept Geog, Sheffield S10 2TN, S Yorkshire, England.
Source Quaternary Science Reviews (0277-3791) (Pergamon-elsevier Science Ltd), 2014-05-01 , Vol. 91 , P. 204-217
DOI 10.1016/j.quascirev.2013.08.019
WOS© Times Cited 27
Keyword(s) Holocene, Ice-rafting, Ice bergs, East Greenland, Iceland
Abstract We examine variations in the ice-rafted sources for sediments in the Iceland/East Greenland offshore marine archives by utilizing a sediment unmixing model and link the results to a coupled iceberg-ocean model. Surface samples from around Iceland and along the E/NE Greenland shelf are used to define potential sediment sources, and these are examined within the context of the down-core variations in mineralogy in the <2 mm sediment fraction from a transect of cores across Denmark Strait. A sediment unmixing model is used to estimate the fraction of sediment <2 mm off NW and N Iceland exported across Denmark Strait; this averaged between 10 and 20%. Both the sediment unmixing model and the coupled iceberg-ocean model are consistent in finding that the fraction of "far-travelled" sediments in the Denmark Strait environs is overwhelmingly of local, mid-East Greenland, provenance, and therefore with a significant cross-channel component to their travel. The Holocene record of ice-rafted sediments denotes a three-part division of the Holocene in terms of iceberg sediment transport with a notable increase in the process starting ca 4000 cal yr BP. This latter increase may represent the re-advance during the Neoglacial period of land-terminating glaciers on the Geikie Plateau to become marine-terminating. The contrast in spectral signals between these cores and the 1500-yr cycle at VM28-14, just south of the Denmark Strait, combined with the coupled iceberg-model results, leads us to speculate that the signal at VM28-14 reflects pulses in overflow waters, rather than an ice-rafted signal.
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