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NOTES ON THE GLACIAL GEOLOGY OF EASTERN MILNE LAND, SCORESBY SUND, EAST GREENLAND
Svend Funder
Svend Funder
Quote:
Sugden & John (1965) have reported from Kjove Land (fig. l) evidence of two glacier advances during which Nordvestfjord and Schuchert Flod valley contained major ice streams, the oldest being earlier than a shoreline at 134 m, the younger contemporaneous with one at 101 m altitude. It seems 1ikely that these two advances are equivalent to the oldest and one of the younger advances of the Milne Land Stages. It is also interesting to note that Lasca (1969), from Skeldal in Kong Oscars Fjord (150 km NNE of Bregnepynt), reported two major glacier advances during which Kong Oscars Fjord was occupied by ice streams; the younger of these occurred just before the formation of a marine delta at 110 m above present sea-level.
Sugden & John (1965) have reported from Kjove Land (fig. l) evidence of two glacier advances during which Nordvestfjord and Schuchert Flod valley contained major ice streams, the oldest being earlier than a shoreline at 134 m, the younger contemporaneous with one at 101 m altitude. It seems 1ikely that these two advances are equivalent to the oldest and one of the younger advances of the Milne Land Stages. It is also interesting to note that Lasca (1969), from Skeldal in Kong Oscars Fjord (150 km NNE of Bregnepynt), reported two major glacier advances during which Kong Oscars Fjord was occupied by ice streams; the younger of these occurred just before the formation of a marine delta at 110 m above present sea-level.
Funder S. 1970. Notes on the glacial geology of eastern Milne Land. Rapport Grønlands Geologiske Undersøgelse 30, 37-42
In one of my posts I drew attention to the signs of ice flow across the plateau, involving an "overflow" ice stream from the Holger Danskes Briller trough:
I am still convinced that this situation prevailed at some stage during the Last Glaciation (Devensian / Wisconsin / Weichselian), but I now think that the morainic ridges on the plateau are unrelated to that phase, and are related instead to the two "Late Glacial" phases of glaciation which we identified in our 1962 fieldwork:
From Sugden and John (1965) -- based on our 1962 research findings
We were not able to do accurate levelling work up on the plateau, but we were quite convinced that there were traces of the highest regional shoreline -- at 134 m -- beneath some of the higher morainic ridges, and that the ice edge prior to deglaciation was at more than 200m asl. The bg morainic ridges associated with Hjornemoraene seem to be associated with the 101m sea-level or stillstand -- and tht is esactly the same relationship as that observed at the south-eastern end of the HDB trough, where there is a massive terminal moraine with a planed top at 101m asl.
The ice edge here was probably grounded, and the glacial advance episode came to an end when the ice edge floated off, permitting the creation of some indistinct shoreline traces at c 134m asl. The ice front probably retreated back into the Nordvestfjord trough. After a period of isostatic uplift associated with deglaciation, there was another short-lived advance of the Nordvestfjord Glacier and a marine stillstand at 101m asl. The ice advanced at least as far as Nordostbugt, and through the HDB trough as far as the end of the eastern lake, where a massive terminal morainic ridge was created. Other shoreline traces at the same level were created on the southern flank of the moraine, overlooking Syd Kap Bay.
All things considered, it appears most likely that there were the following Last Glaciation episodes in Kjove Land and on Pythagoras Bjerg:
1. Large-scale inundation of the landscape by ice from the Nordvestfjord Glacier and from other glaciers in the southern Staunings Alps. Diffluent ice flow through HDB trough and over part of the Pythagoras Bjerg plateau. Large scale isostatic depression of crust. Relative sea-level maybe 150m asl.
2. Substantial ice melting and ice edge retreat, leaving Kjove Land ice free and submerged -- highest shorelines indistinct. Marine limit unknown.
3. Glacier advance, covering Kjove land, Syd Kap Bay etc but leaving Pythagoras Bjerg unglaciated or more probably supporting a local and relatively thin ice cap. Higher morainic ridges formed on ice edges on the eastern and southern flanks of the Pythagoras Bjerg upland. Multiple ridges formed between 300m and 100m asl as ice surface dropped. Shoreline traces at around 134m asl after deglaciation - floating off of ice edge. Older Dryas age?
4. Renewed glaciation and advance. Ice from Nordvestfjord flowed eastwards as far as Nordostbugt, leaving a prominent morainic ridge and associated features. Eastern flank of upland overlooking Kjoveland unaffected by glacier ice. HDB terminal moraine created. Sea level at c 101m.
The massive flat-topped HDB terminal Moraine, related to a substantial glacier readvance (Younger Dryas?) through the trough and towards the camera.
Surveying on the flat surface of the HDB terminal moraine -- at 101m asl
5. Glacier retreat up Nordvestfjord and ice edge retreat up all Staunings Alps glacial troughs. Substantial meltwater activity and delta formation at stillstands as sea level dropped episodically due to isostatic recovery and short-lived climatic oscillations. Creation of Gurreholm "staircase" and many other shoreline traces in Schuchertdal.
6. No further substantial glacier advances until Neoglacial / Little Ice Age expansion of valley glaciers within last 500 years.
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I still have some questions regarding the extent of glacier ice in Schuchertdal during the Milne Land stage. Funder and others think that there was an ice front in the middle section of the valley, south of the Bjørnbo Glacier trough. I don't think the evidence for that has been presented in adequate detail, although there are references to lateral moraine ridges on the valley sides with a relief of c 5m. But marine sediments extend up the valley as far as the Roslin Gletscher morainic loop, and they contain shell fragments and other organic materials dating back as far as 11,000 yrs BP. The details are still to be worked out.........
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