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TitleSedimentary and rock magnetic signatures and event scenarios of deglacial outburst floods from the Laurentian Channel Ice Stream
AuthorLeng, W; von Dobeneck, T; Bergmann, F; Just, J; Mulitza, S; Chiessi, C M; St-Onge, G; Piper, D J WORCID logo
SourceQuaternary Science Reviews vol. 186, 2018 p. 27-46,
LinksSupplementary Data - Données supplémentaires (Pangaea)
LinksSupplementary Data - Données supplémentaires (Pangaea)
LinksSupplementary Data - Données supplémentaires (Pangaea)
Alt SeriesNatural Resources Canada, Contribution Series 20170342
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf; html
ProvinceNewfoundland and Labrador; Eastern offshore region
AreaGrand Banks of ; Laurentian Channel; Laurentian Fan
Lat/Long WENS -55.2500 -53.2500 44.7500 42.7500
Subjectsmarine geology; surficial geology/geomorphology; geophysics; geochronology; stratigraphy; continental margins; continental slope; glacial history; deglaciation; ice retreat; meltwater channels; marine sediments; marine sediment cores; core analysis; glacial deposits; muds; moraines; tills; ice rafting; ice scours; detritus; erosion; sediment transport; provenance; source areas; sediment dispersal; dispersal patterns; magnetic properties; hematite; magnetite; grain size analyses; geophysical surveys; seismic surveys, marine; acoustic surveys; radiometric dating; radiocarbon dating; carbon-14 dates; bathymetry; geophysical logging; resistivity logging; magnetic susceptibility; conductivity; porosity; lithostratigraphy; models; stratigraphic correlations; Grand Banks Slope; Laurentian Channel Ice Stream; Laurentide Ice Sheet; Heinrich Event 1; Heinrich Event 2; Last Glacial Maximum; Appalachian Ice Complex; Laurentian Moraine; glaciomarine sediments; Phanerozoic; Cenozoic; Quaternary
Illustrationslocation maps; geoscientific sketch maps; tables; seismic profiles; cross-sections; lithologic sections; stratigraphic correlations; geophysical logs; profiles; images; plots; models; schematic representations
ProgramOffshore Geoscience
Released2018 02 26
AbstractEastern Canadian margin sediments bear testimony to several catastrophic deglacial meltwater discharges from the retreating Laurentide Ice Sheet. The reddish-brown plumite layers deposited on the levees of the Laurentian Fan valleys have been recognized as indications of multiple outburst floods between Heinrich events 2 and 1. Five event layers have been consistently recorded in three new gravity cores retrieved on the SW Grand Banks slope and comply with the previously published Laurentian Fan core MD95 2029. The apparently huge extent of these outburst plumes around the Laurentian Fan as well as their causes and consequences are investigated in this study using physical properties, rock magnetic and grain-size analyses, together with seismoacoustic profiling. We provide the first detailed 14C ages of the outburst event sequence and discuss their recurrence intervals in the context of regional ice retreat. Compared to the hemipelagic interlayers, event layers have overall uniform and systematic changes of rock-magnetic properties. Hematite contents increase over time and proximally while magnetite grain sizes fine upwards and spatially away from the fan. Based on the sediment composition and load, we argue that these plumites were formed by recurrent erosion of glacial mud deposits in the Laurentian Channel by meltwater outbursts. Three alternative glaciological scenarios are evaluated: in each case, the provenance of the transported sediment is not an indicator of the precise source of the meltwater.
Summary(Plain Language Summary, not published)
Very thick glacial-age red muds on Laurentian Fan were deposited by large sub-glacial meltwater discharges. This contributes to our understanding of how glacial history influences geohazards.

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