Sedimentary processes and seabed morphology of the Southwest Greenland margin
Bathymetric and seismic data from the Southwest Greenland margin have been used to provide an integrated shelf-to-basin overview of the margin architecture between 57° N and 64° N. A variety of glacially formed morphologic features, contour current-related erosion and sedimentary deposits, and evidence of downslope sediment transport via canyons, channels and gullies is found here. The study area is characterized by two major canyons bordering Fylla Bank in the northern part and a narrow shelf and steep slope to the south, where erosion due to strong boundary currents occur down to c. 3000 m water depth. The narrow shelf area appears to be an intra-ice stream area, and numerous channels and gullies on the upper slope point to hyperpycnal melt water release from a stable or retreating wide ice front. Further southward, the shelf is widening and the morphology indicates dominance of former ice stream activity. This difference in glaciation style may reflect the different bedrock types. Sedimentary and morphologic characteristics of the Fylla Bank canyons and some of the slope gullies and channels point to actual cascading of dense winter water or hyperpycnal melt water flow from the shelf. Deep-water channels at the base of the slope evidence transport of Greenland-derived sediment to the central Labrador Sea basin and buried channels further west indicate a former contribution to the Northwest Atlantic Mid-Ocean Channel (NAMOC) system. However, in contrast to widespread turbidite channels on the present seabed bordering NAMOC to the west, east of NAMOC contourite deposits have largely covered the deep-water tributary turbidite channels originating from the Greenland margin.
KeywordsSouthwest Greenland margin Seabed morphology Deep-sea channels Contourite deposits Canyons
Thanks to the Geological Survey of Denmark and Greenland (GEUS) for providing time and data for this study. Special thanks to W. Weng (GEUS) for compiling the bathymetric maps. Thanks are also due to the three anonymous reviewers for their helpful and constructive comments on an earlier version of the manuscript.
Compliance with ethical standards
Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
- 1.Nansen F (1904) The bathymetric features of the North polar seas. Sci Results Norweg Polar Exped 4:1893–1896 (Christiania) Google Scholar
- 2.Sommerhoff G (1975) Glaziale Gestaltung und marine Überformung der Schelfbänke vor SW-Grönland. Polarforsch 45:22–31Google Scholar
- 3.Sommerhoff G (1981) Geomorphologische Prozesse in der Labrador- und Irminger See. Ein Beitrag zur submarinen Geomorphologie einer subpolaren Meeresregion. Polarforsch 51:175–191Google Scholar
- 4.Brett CP, Zarudzki EFK (1979) Project Westmar—a shallow marine geophysical survey on the West Greenland continental shelf. Geol Surv Greenl 87:1–27Google Scholar
- 18.Streuff K, Ó Cofaigh C, Hogan K, Jennings AE, Lloyd J, Noormets R, Nielsen T, Kuijpers A, Dowdeswell JA, Weinrebe W (2016) Seafloor geomorphology and glaciomarine sedimentation associated with fast-flowing ice sheet outlet glaciers in Disko Bay, West Greenland. Quat Sci Rev 169:206–230. https://doi.org/10.1016/j.quascirev.2017.05.021 CrossRefGoogle Scholar
- 22.Ryan JC, Dowderswell JA, Hogan KA (2016) Three cross-shelf troughs on the continental shelf of SW Greenland from Olex data. In: Dowdeswell JA, Canals M, Jacobsen M, Tood BJ, Dowdeswell EK, Hogan KA (eds) Atlas of Submarine Glacial landforms: morden, quaternary and ancient. Geological Socity, London, pp 167–168 (Memoirs 46) Google Scholar
- 23.Gregersen U, Knutz PC, Nøhr-Hansen H, Sheldon E, Hopper JR (2019) Tectonostratigraphy and evolution of the West Greenland continental margin. Bull Geol Soc Den 67:1–21Google Scholar
- 24.Henriksen N, Higgins AK, Kalsbeek F, Pulvertaft TC (2009) Greenland from Archaean to Quaternary. Descriptive text to the 1995 Geological map of Greenland 1: 2 500 000, 2nd edn. Geological Survey of Denmark and Greenland Bulletin, Denmark, pp 18–126Google Scholar
- 39.Myers RA, Mertz G, Helbig JA (1990) Long period changes in the salinity of Labrador Sea water. ICES C.M.1990′ C 21:15Google Scholar
- 40.Clarke RA (1984) Transport trough the cape farewell-flemish cap section. Rapp P-V Reun-Cons Int Explor Mer 185:120–130Google Scholar
- 47.Jakobsson M, Mayer L, Coakley B, Dowdeswell JA, Forbes S, Fridman B, Hodnesdal H, Noormets R, Pedersen R, Rebesco M, Schenke HW, Zarayskaya Y, Accettella D, Armstrong A, Anderson RM, Bienhoff P, Camerlenghi A, Church I, Edwards M, Gardner JV, Hall JK, Hell B, Hestvik O, Kristoffersen Y, Marcussen C, Mohammad R, Mosher D, Nghiem SV, Pedrosa MT, Travaglini PG, Weatherall P (2012) The International bathymetric Chart of the Arctic Ocean (IBCAO). Version 3.0. Geophys Res Lett 39:L12609Google Scholar
- 49.Kenyon NH, Ivanov MK, Akhmetzhanov AM, Kozlova EV, Mazzini A (2004) Interdisciplinary studies of North Atlantic and Labrador Sea Margin architecture and sedimentary processes IOC technical, vol 68. UNESCO, ParisGoogle Scholar
- 62.Funder S, Kjeldsen KK, Kjær KH, Ó Cofaigh C (2011) The Greenland Ice Sheet during the past 300, 000 years: A review. Dev Quat Sci 15:699–713Google Scholar
- 65.Piper DJW (2001) Late Cenozoic evolution of the continental margin of eastern Canada. Norwegian J Geol 85:305–318Google Scholar