|Title||Controls on the formation of turbidity current channels associated with marine-terminating glaciers and ice sheets|
|Author||Pope, E L; Normandeau, A; Ó Cofaigh, C; Stokes, C R; Talling, P J|
|Source||Marine Geology vol. 415, 10595, 2019 p. 1-21, https://doi.org/10.1016/j.margeo.2019.05.010 Open Access|
|Alt Series||Natural Resources Canada, Contribution Series 20180400|
|Media||paper; on-line; digital|
|File format||pdf (Adobe® Reader®); html|
|Lat/Long WENS|| -76.0000 -20.0000 84.0000 59.0000|
|Subjects||marine geology; surficial geology/geomorphology; hydrogeology; geophysics; Nature and Environment; turbidity currents; submarine features; channels; marine sediments; sediment transport; sediment
dispersal; sediment volumes; glaciers; ice sheets; carbon; geophysical interpretations; bathymetry; continental margins; continental shelf; fiords; coastal environment; ice margins; ice flow; glacial deposits; moraines; remote sensing; satellite
imagery; hydrologic environment; drainage systems; runoff; flow systems; sedimentation rates; morphology; Greenland Ice Sheet; Fresh water; elevations|
|Illustrations||location maps; geoscientific sketch maps; tables; satellite images; plots; schematic representations|
Geoscience Marine Geohazards|
|Released||2019 06 04|
|Abstract||Submarine channels, and the sediment density flows which form them, act as conduits for the transport of sediment, macro-nutrients, fresher water and organic matter from the coast to the deep sea. These
systems are therefore significant pathways for global sediment and carbon cycles. However, the conditions that permit or preclude submarine channel formation are poorly understood, especially when in association with marine-terminating glaciers.
Here, using swath-bathymetric data from the inner shelf and fjords of northwest and southeast Greenland, we provide the first paper to analyse the controls on the formation of submarine channels offshore of numerous marine-terminating glaciers. These
data reveal 37 submarine channels: 11 offshore of northwest Greenland and 26 offshore of southeast Greenland. The presence of channels is nearly always associated with: (1) a stable glacier front, as indicated by the association with either a moraine
or grounding-zone wedge; and (2), a consistent seaward sloping gradient. In northwest Greenland, turbidity current channels are also more likely to be associated with larger glacier catchments with higher ice and meltwater fluxes which provide higher
volumes of sediment delivery. However, the factors controlling the presence of channels in northwest and southeast Greenland are different, which suggest some complexity about predicting the occurrence of turbidity currents in glacier-influenced
settings. Future work on tidewater glacier sediment delivery rates by different subglacial processes, and the role of grain size and catchment/regional geology is required to address uncertainties regarding the controls on channel formation.
|Summary||(Plain Language Summary, not published)|
Submarine channels, and the turbidity currents which form and navigate them, act as conduits for the transport of sediment, macro-nutrients, fresher
water and organic matter from the coast to the deep sea. The exact conditions that permit or prevent submarine channel formation are poorly understood, especially when in association with marine-terminating glaciers. Here, using swath-bathymetric
data from the inner shelf and fjords of Northwest and Southeast Greenland, we analyse the controls on the formation of submarine channels offshore marine-terminating glaciers.