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TitleReconstructing ice-margin retreat using delta morphostratigraphy
AuthorDietrich, P; Ghienne, J F; Normandeau, AORCID logo; Lajeunessse, P
SourceScientific Reports vol. 7, 16936, 2017, 10 pages, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20170165
PublisherSpringer Nature
Mediapaper; on-line; digital
File formatpdf
NTS12D; 12C; 12E; 12F; 12L; 12K; 12M; 12N; 22
AreaCote-Nord; Gulf of St-Lawrence
Lat/Long WENS -73.0000 -60.0000 52.0000 48.0000
Subjectssedimentology; surficial geology/geomorphology; deltaic sediments; deltaic facies; deltaic deposits; deltas; ice movement directions; ice flow; ice retreat; ice sheets; glaciofluvial deposits; ice contact deposits; sedimentation models; sedimentation dynamics; sediment reworking; Romaine; Aguanish; Magpie; Nastashquan; Sept-Iles; Manitou; Sainte-Marguerite; Pasteur; Walker; Godbout; Manicouagan; Outardes; Betsiamites; Escoumins; Pentecote
Illustrationslocation maps; schematic diagrams; tables
Released2017 12 05
AbstractThe paleogeographic reconstruction of the successive inland positions of a retreating ice sheet is generally constrained by mapping moraines. However, deltaic complexes constructed by sedimentcharged meltwater can also provide a record of the retreating ice-margin positions. Here, we examine a serie of ice-contact, ice-distal glaciofluvial and paraglacial depositional systems that developed
along the Québec North Shore (eastern Canada) in the context of falling relative sea level during the northward retreat of the Laurentide Ice Sheet (LIS). Ice-contact depositional systems formed when the LIS was stillstanding along the Québec North Shore. Subsequent inland retreat of the ice margin generated glacial meltwaters feeding sediment to glaciofluvial deltas, leading to their rapid progradation. The retreat of the ice margin from drainage basins was marked by the onset of paraglacial processes such as the shutdown of delta progradation, severe fluvial entrenchment, and deposition of shallow-marine strata. Four end-member scenarios describe the spatial and stratigraphic distribution of these three depositional systems (ice-contact deposits, ice-distal glaciofluvial deltas, and paraglacial
suites). They reflect both the inherited drainage basin physiography and the retreat pattern of the ice margin. Applied to twenty deltaic complexes, these end-members allowed us to refine the model of LISmargin retreat over southeastern Québec.
Summary(Plain Language Summary, not published)
Deltaic systems constructed when glacial meltwaters transported large volumes of sediment to the sea in a context of rapidly falling relative sea level provides a record of the former positions of the retreating Laurentide ice margin.

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