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Quartz content and the quartz-to-plagioclase ratio determined by X-ray diffraction: a proxy for ice rafting in the northern North Atlantic?

Moros, M; McManus, JF; Rasmussen, T; Kuijpers, A; Dokken, T; Snowball, Ian LU ; Nielsen, T and Jansen, E (2004) In Earth and Planetary Science Letters 218(3-4). p.389-401
Abstract
Many paleoceanographic reconstructions of the glacial North Atlantic include estimates of iceberg discharge, which are based on the variable abundance of ice-rafted detritus (IRD) in deep-sea sediments. IRD abundance is most often determined by the mechanical separation and painstaking counting of terrigenous particles larger than a specified threshold grain size, typically 150 mum. Here we present a new proxy for IRD based on X-ray diffraction (XRD) analysis of bulk sediments. This approach complements results obtained from standard techniques while offering several distinct advantages. In addition to the rapid production of objective data, XRD measurements on bulk sediments are sensitive to a broader and more characteristic grain size... (More)
Many paleoceanographic reconstructions of the glacial North Atlantic include estimates of iceberg discharge, which are based on the variable abundance of ice-rafted detritus (IRD) in deep-sea sediments. IRD abundance is most often determined by the mechanical separation and painstaking counting of terrigenous particles larger than a specified threshold grain size, typically 150 mum. Here we present a new proxy for IRD based on X-ray diffraction (XRD) analysis of bulk sediments. This approach complements results obtained from standard techniques while offering several distinct advantages. In addition to the rapid production of objective data, XRD measurements on bulk sediments are sensitive to a broader and more characteristic grain size range than counts of individual coarse lithic fragments. The technique is demonstrated in a study of 12 sediment cores from the North Atlantic. Bulk quartz content and the quartz-to-plagioclase ratio exhibit peak-to-peak correspondence to manual counting results, which verifies the identification of large IRD influxes. The XRD data also reveal variations between the manually identified peaks, suggesting increased sensitivity to low-level, distal, or sea-ice sources of IRD. A saw-tooth pattern emerges in many IRD events, which supports a link between ice rafting and atmospheric temperature changes over Greenland, and providing further evidence of the influence of climate on iceberg discharges. (C) 2003 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
X-ray diffraction, ice rafting, plagioclase, North Atlantic, quartz
in
Earth and Planetary Science Letters
volume
218
issue
3-4
pages
389 - 401
publisher
Elsevier
external identifiers
  • wos:000188887600012
  • scopus:1142281155
ISSN
1385-013X
DOI
10.1016/S0012-821X(03)00675-7
language
English
LU publication?
yes
id
7d95ca11-31c3-474f-bf96-688016c4d2ee (old id 288425)
date added to LUP
2007-10-28 15:46:36
date last changed
2017-04-23 03:36:56
@article{7d95ca11-31c3-474f-bf96-688016c4d2ee,
  abstract     = {Many paleoceanographic reconstructions of the glacial North Atlantic include estimates of iceberg discharge, which are based on the variable abundance of ice-rafted detritus (IRD) in deep-sea sediments. IRD abundance is most often determined by the mechanical separation and painstaking counting of terrigenous particles larger than a specified threshold grain size, typically 150 mum. Here we present a new proxy for IRD based on X-ray diffraction (XRD) analysis of bulk sediments. This approach complements results obtained from standard techniques while offering several distinct advantages. In addition to the rapid production of objective data, XRD measurements on bulk sediments are sensitive to a broader and more characteristic grain size range than counts of individual coarse lithic fragments. The technique is demonstrated in a study of 12 sediment cores from the North Atlantic. Bulk quartz content and the quartz-to-plagioclase ratio exhibit peak-to-peak correspondence to manual counting results, which verifies the identification of large IRD influxes. The XRD data also reveal variations between the manually identified peaks, suggesting increased sensitivity to low-level, distal, or sea-ice sources of IRD. A saw-tooth pattern emerges in many IRD events, which supports a link between ice rafting and atmospheric temperature changes over Greenland, and providing further evidence of the influence of climate on iceberg discharges. (C) 2003 Elsevier B.V. All rights reserved.},
  author       = {Moros, M and McManus, JF and Rasmussen, T and Kuijpers, A and Dokken, T and Snowball, Ian and Nielsen, T and Jansen, E},
  issn         = {1385-013X},
  keyword      = {X-ray diffraction,ice rafting,plagioclase,North Atlantic,quartz},
  language     = {eng},
  number       = {3-4},
  pages        = {389--401},
  publisher    = {Elsevier},
  series       = {Earth and Planetary Science Letters},
  title        = {Quartz content and the quartz-to-plagioclase ratio determined by X-ray diffraction: a proxy for ice rafting in the northern North Atlantic?},
  url          = {http://dx.doi.org/10.1016/S0012-821X(03)00675-7},
  volume       = {218},
  year         = {2004},
}