Well, the informant has got it all wrong, and if a group of senior glaciologists and glacial geomorphologists says that the glacial transport thesis is perfectly feasible from a practical and theoretical standpoint, that's good enough for me.
'Dynamic cycles, ice streams and their impact on the extent, chronology and deglaciation of the British–Irish ice sheet.'
Alun Hubbard, Tom Bradwell, Nicholas Golledge, Adrian Hall, Henry Patton, David Sugden, Rhys Cooper, Martyn Stoker
Quaternary Science Reviews 28 (2009) 759–777
Back to Nordvestfjord and Scoresbysund:
The Nordvest Fjord - Scoresby Sund system has clearly been one of the major outlet routes for ice from the Greenland Ice Sheet, during the whole of the Pleistocene and maybe for much longer than that. Even today the Daugaard Jensens Gletscher, near the head of the fjord, is possibly the most productive glacier in the whole of Greenland. Because the ice here has been streaming so effectively in a narrow and constrained trough, the rate of downcutting has been impressive indeed. There are no proper bathymetric charts, but from the scattered soundings that have been made we see depths of 1372m, 1459m, 1372m, 1150m, 1237m, and 1290m between Eskimo Bugt and Syd Kap. The deepest sounding of all is 1508m (4,947 ft). These soundings show that the fjord is substantially deeper than Sognefjord in Norway (maximum known depth 1308m), which has just one short stretch deeper than 1200m.
Sognefjord long profile, Norway. Note that there is a 1000m high reverse slope at the trough exit, over a distance of c 20 km. This is the threshold and the point at which diffluence or lateral spreading of the ice has reduced erosional capacity to a very low level.
But here on the flanks of Nordvest Fjord the plateau ice caps and mountain summits are almost all over 2000m (6561 ft), whereas there is little land over 1600m on the flanks of Sognefjord. So the full depth of Nordvest Fjord over a distance of about 80 miles is approx 3300m or 11,000 feet. I'll let somebody else work out how much material has been eroded and removed by ice from a trough of this size....... but it is indisputable that this is the deepest, longest and most dramatic fjord system on earth.
The deepest section of the fjord begins about 20 km from the DJ Glacier snout, and continues for about 30 km with depths around 1400m before shallowing to around 1200m; this may reflect erosive power or capacity, but it may well be that sediments are much thicker in the middle and outer sections of the fjord, with the bedrock floor maybe several hundreds of metres below the "sediment floor". Some troughs have beds which are divided up into a series of connected basins. According to Julian Dowdeswell and others the bed of Nordvestfjord is like this, with a series of deep basins (over 1200m deep) separated by sills between 600m and 900m deep. I have not seen the detailed long profiles, and so we can but speculate as to whether the sills coincide with outcrops of highly resistant rocks (on the basis of lithology or structure) and whether the basins coincide with pulses or additions to glacier discharge derived from tributary glaciers. Near the trough exit the bedrock floor rises very steeply indeed, but sediments in this exit zone can be very think as well. In Hall Bredning the glacial sediments are at least 100m thick. But the essential point, from the long profile soundings, is that the reverse slope is truly spectacular, rising from a depth of 1270m to the threshold shallows in only about 5 km.
This is an Ernst Hofer image of the Bear Islands, looking NW from the southern tip of the archipelago. Note the winding ridge of moraine, on the island called Sulugssut. Is it linked to the Milne Land stage moraines in Kjove Land? Some fieldwork is needed......
"Analytic glacial erosion models suggest that ice flows passing through constrained spaces such as mountain passes produced enhanced erosion beneath thicker, faster ice flows, which deepens the channel below areas both upstream and downstream. The underlying physical phenomena is that erosion increases with the rate of ice discharge. Although this simplifies complex relationships among time-varying climates, ice sheet behaviors and bed characteristics, it is based on the general recognition that enhanced ice discharges typically increase the erosion rate. This is because the basal sliding rate and the erosion rate are interrelated and driven by the same variables: the ice thickness, the underlying bed slope, the overlying glacial slope and the basal temperature. As a result, the modelled fjords are deepest through the narrowest channels (i.e., regions with the highest surrounding highest topography). This corresponds with actual physical observations of fjords."
Where was the ice surface when the Nordvestfjord Glacier was reaching its exit and starting to spread laterally? Let's be conservative and pretend that the snout surface was around 200m in the vicinity of Syd Kap. Suddenly a glacier that was 1.4 km thick was forced to become a glacier approx 400m thick, flowing over the threshold. The ice volume in the threshold area was thus 1 x 7 x 5 kms = 35 cubic km of ice being forced like toothpaste out of a tube, up a reverse slope 1000m high, and then away into the unrestricted terrain of Hall Bredning.