Abstract:
The modern depositional environment of the northern
epicontinental Barents Sea varies from proximal to distal
glaciomarine. The regional surface sediment distribution is
controlled by erosion of shallow banks of the Pleistocene glaciated
surface, with the fine material deposited in the deep basins.
Near-bottom nepheloid layers are often observed indicating that fine
grained sediments are being transported under present conditions.
Minor additional sediment is supplied by iceberg rafting englacial
material and sea-ice containing aeolian, resuspended, and beach
sediments.
Glacial flour is supplied by several large stable meltwater
outflow locations along the ice front. Because the water is fresh and
nearly the same temperature as the ambient coastal water, it is
bouyant. Although the traction load deposits as the meltwater plume
rises to the sea surface, sand (as well as finer material) may be
suspended. This material deposits from suspension at some distance
from the discharge location (dependent on both the sediment settling
velocity and the velocity of the ambient coastal water, resulting in
well-sorted deposits near the outflow location). Most of the sediment
in suspension is observed to deposit within a 5km radius of the
outflow location, and suspended matter samples obtained 18km offshore
were at background levels. However, meltwater plumes can often be
observed in the surface water (in satellite photographs) at distances
of 30km downstream, indicating transport of glacial sediments along
the ice front.
Near the Nordaustlandet glacier front surface sediments are
disturbed by glaciers advances and retreats which mechanically rework
the sediment surface. The southwestern portion of the glacier front,
Brasvellbreen, surged 18km between 1936 and 1938. An end moraine was
deposited at the maximum extent of the surge. The ice then stagnated
and disintegrated through calving. At present on the eastern portion
of the Brasvellbreen ice front is active with frequent small (less
than 50m) glacier advances and retreats. Evidence for this is shown
by the minor ridge and swale moraines in this eastern area.
