Microfeatures of modern sea-ice-rafted sediment and implications for paleo-sea-ice reconstructions

Kristen St John, Sandra Passchier, Brooke Tantillo, Dennis Darby, Lance Kearns

Research output: Contribution to journalArticleResearchpeer-review

9 Citations (Scopus)

Abstract

Distinguishing sea-ice-rafted debris (SIRD) from iceberg-rafted debris is crucial to an interpretation of ice-rafting history; however, there are few paleo-sea-ice proxies. This study characterizes quartz grain microfeatures of modern SIRD from the Arctic Ocean, and compares these results with microfeatures from representative glacial deposits to potentially differentiate SIRD from ice-rafted sediments which have been recently subjected to glacial processes. This allows us to evaluate the use of grain microfeatures as a paleo-sea-ice proxy. SIRD grains were largely subrounded, with medium relief, pervasive silica dissolution and a high abundance of breakage blocks and microlayering. The glacial grains were more angular, with lower relief and higher abundances of fractures and striations/gouges. Discriminate analysis shows a distinct difference between SIRD and glacial grains, with <7% of the SIRD grains containing typical glacial microtextures, suggesting this method is a useful means of inferring paleo-sea-ice presence in the marine record. We propose that differences in microfeatures of SIRD and glacial ice-rafted debris reflect differences in sediment transport and weathering histories. Sediment transported to a coastal setting and later rafted by sea ice would be subject to increased chemical weathering, whereas glaciers that calve icebergs would bypass the coastal marine environment, thus preserving their glacial signature.

Original languageEnglish
Pages (from-to)83-93
Number of pages11
JournalAnnals of Glaciology
Volume56
Issue number69
DOIs
StatePublished - 1 Jan 2015

Fingerprint

ice-rafted debris
sea ice
sediment
iceberg
relief
ice rafting
marine record
striation
chemical weathering
bypass
glacial deposit
breakage
history
sediment transport
coastal zone
marine environment
glacier
weathering
silica
dissolution

Keywords

  • Arctic glaciology
  • Icebergs
  • Paleoclimate
  • Sea ice
  • Sedimentology

Cite this

St John, Kristen ; Passchier, Sandra ; Tantillo, Brooke ; Darby, Dennis ; Kearns, Lance. / Microfeatures of modern sea-ice-rafted sediment and implications for paleo-sea-ice reconstructions. In: Annals of Glaciology. 2015 ; Vol. 56, No. 69. pp. 83-93.
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Microfeatures of modern sea-ice-rafted sediment and implications for paleo-sea-ice reconstructions. / St John, Kristen; Passchier, Sandra; Tantillo, Brooke; Darby, Dennis; Kearns, Lance.

In: Annals of Glaciology, Vol. 56, No. 69, 01.01.2015, p. 83-93.

Research output: Contribution to journalArticleResearchpeer-review

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