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Timing and controls on the delivery of coarse sediment to deltas and submarine fans on a formerly glaciated coast and shelf

2017; Geological Society of America; Linguagem: Inglês

10.1130/b31678.1

1943-2674

Alexandre Normandeau, Pierre Dietrich, Patrick Lajeunesse, Guillaume St‐Onge, Jean‐François Ghienne, Mathieu J. Duchesne, Pierre Francus,

Methane Hydrates and Related Phenomena

Research Article| June 30, 2017 Timing and controls on the delivery of coarse sediment to deltas and submarine fans on a formerly glaciated coast and shelf Alexandre Normandeau; Alexandre Normandeau † 1Geological Survey of Canada—Atlantic, 1 Challenger Drive, Dartmouth, Nova Scotia B2Y 4A2, Canada2Centre d'Études Nordiques & Département de Géographie, Université Laval, 2405 Rue de la Terrasse, Québec, Québec G1V 0A6, Canada †alexandre.normandeau@canada.ca Search for other works by this author on: GSW Google Scholar Pierre Dietrich; Pierre Dietrich 3Institut de Physique du Globe de Strasbourg, UMR 7516 CNRS/Université de Strasbourg, 1 rue Blessig, 67084 Strasbourg, France4Department of Geology, Auckland Park Kingsway Campus, University of Johannesburg, Johannesburg, South Africa Search for other works by this author on: GSW Google Scholar Patrick Lajeunesse; Patrick Lajeunesse 2Centre d'Études Nordiques & Département de Géographie, Université Laval, 2405 Rue de la Terrasse, Québec, Québec G1V 0A6, Canada Search for other works by this author on: GSW Google Scholar Guillaume St-Onge; Guillaume St-Onge 5Institut des Sciences de la Mer de Rimouski (ISMER), Canada Research Chair in Marine Geology & GEOTOP, Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada Search for other works by this author on: GSW Google Scholar Jean-François Ghienne; Jean-François Ghienne 3Institut de Physique du Globe de Strasbourg, UMR 7516 CNRS/Université de Strasbourg, 1 rue Blessig, 67084 Strasbourg, France Search for other works by this author on: GSW Google Scholar Mathieu J. Duchesne; Mathieu J. Duchesne 6Geological Survey of Canada–Québec, 490 rue de la Couronne, Québec, Québec G1K 9A9, Canada Search for other works by this author on: GSW Google Scholar Pierre Francus Pierre Francus 7Institut National de la Recherche Scientifique, Centre Eau Terre Environnement & GEOTOP, 490 rue de la Couronne, Québec, Québec G1K 9A9, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Alexandre Normandeau † 1Geological Survey of Canada—Atlantic, 1 Challenger Drive, Dartmouth, Nova Scotia B2Y 4A2, Canada2Centre d'Études Nordiques & Département de Géographie, Université Laval, 2405 Rue de la Terrasse, Québec, Québec G1V 0A6, Canada Pierre Dietrich 3Institut de Physique du Globe de Strasbourg, UMR 7516 CNRS/Université de Strasbourg, 1 rue Blessig, 67084 Strasbourg, France4Department of Geology, Auckland Park Kingsway Campus, University of Johannesburg, Johannesburg, South Africa Patrick Lajeunesse 2Centre d'Études Nordiques & Département de Géographie, Université Laval, 2405 Rue de la Terrasse, Québec, Québec G1V 0A6, Canada Guillaume St-Onge 5Institut des Sciences de la Mer de Rimouski (ISMER), Canada Research Chair in Marine Geology & GEOTOP, Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada Jean-François Ghienne 3Institut de Physique du Globe de Strasbourg, UMR 7516 CNRS/Université de Strasbourg, 1 rue Blessig, 67084 Strasbourg, France Mathieu J. Duchesne 6Geological Survey of Canada–Québec, 490 rue de la Couronne, Québec, Québec G1K 9A9, Canada Pierre Francus 7Institut National de la Recherche Scientifique, Centre Eau Terre Environnement & GEOTOP, 490 rue de la Couronne, Québec, Québec G1K 9A9, Canada †alexandre.normandeau@canada.ca Publisher: Geological Society of America Received: 13 Oct 2016 Revision Received: 22 Dec 2016 Accepted: 16 Apr 2017 First Online: 30 Jun 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2017 Geological Society of America GSA Bulletin (2017) 129 (11-12): 1424–1441. https://doi.org/10.1130/B31678.1 Article history Received: 13 Oct 2016 Revision Received: 22 Dec 2016 Accepted: 16 Apr 2017 First Online: 30 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Alexandre Normandeau, Pierre Dietrich, Patrick Lajeunesse, Guillaume St-Onge, Jean-François Ghienne, Mathieu J. Duchesne, Pierre Francus; Timing and controls on the delivery of coarse sediment to deltas and submarine fans on a formerly glaciated coast and shelf. GSA Bulletin 2017;; 129 (11-12): 1424–1441. doi: https://doi.org/10.1130/B31678.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The evolution of deltas and submarine fans is often envisioned as largely controlled by relative sea-level variations. However, in some cases, relative sea level can have less effect on delta and submarine fan activity than sediment supply and shelf geomorphology. In order to document the relative importance of these three factors on deltaic and submarine fan evolution in a formerly glaciated environment, this paper documents the delivery of coarse sediment to the Laurentian Channel (eastern Canada). The well-constrained stratigraphic and geomorphologic framework of both the glacio-isostatically uplifted deltas and the modern Laurentian Channel fans allows us to document and contrast the evolution of river-fed deltas, river-fed canyon/fan systems, and longshore drift–fed fans during deglacial and postglacial times. The evolution of these different types of fans can be divided into three phases. The first phase was characterized by delta progradation on the shelf while relative sea level was at its maximum, although already falling, and the ice margin gradually retreated inland. The second phase was characterized by the delivery of deltaic sediment in the deep realm of the Laurentian Channel, permitted by the supply of large amounts of glaciogenic sediments derived from the retreating ice margin and the lowering of the relative sea level. At the same time, sediment instability along the steep Laurentian Channel formed small incisions that evolved into submarine canyons where the narrow shelf allowed the trapping of longshore sediment. The third phase was characterized by the withdrawal of the ice margin from the watershed of the main rivers and the drastic decrease in sediment supply to the deltas. Consequently, the delta fronts experienced strong coastal erosion, even though relative sea level was still lowering in some cases, and the eroded sediments were transferred onto the shelf and to adjacent bays. This transfer of coastal sediments allowed the continued activity of longshore drift–fed canyons. The retreat of the ice margin from the watersheds thus controlled the supply of sediment and induced a change in delta type, passing from river-dominated to wave-dominated deltas. This paper highlights the role of the type of sediment supply (ice-contact, glaciofluvial, and longshore drift) in the timing and activity of submarine fans in high-latitude environments. A conceptual model is proposed for high-latitude shelves where sediment delivery to submarine fans is mostly controlled by structural inheritance (watershed area and shelf geomorphology) rather than relative sea-level fluctuations. Therefore, although relative sea level fell during delta progradation, this study demonstrates that it was not the main contributor to delta and submarine fan growth. This has wider implications for the extraction of sea-level information from stratigraphic successions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.