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Thursday, 18 January 2024

Scoresby Sund -- the mystery of "moraine corner"

 




Thanks to some amazing snow and light conditions in this satellite image of Kjove land in East Greenland, we can see extraordinary detail.  Dave Sugden and I described the wonderful morainic ridges to the north and west of "moraine corner" in a paper published in 1965, following our fieldwork in this area in 1962.  We were somewhat mystified by the ridges at the time, and as shown in the annotations above we concluded that they were probably marginal or lateral moraines formed on the flanks of a nunatak by two streams of ice, one from the Nordvestfjord flowing eastwards over Syd Kap as the ice spread into Hall Bredning, and the other flowing SE and then S from the Holger Danskes Briller diffluent trough.  

This explanation has been accepted by most subsequent researchers as they tried to unravel the events of the "Milne Land Stage" dated to around 11,000 years ago.  David and I established that when the ice wasted away, sea level was at c 101m above its present level.  This is the level of the planed top of the big terminal (recessional?) moraine at the exit of the Holger Danskes Briller trough.  However, the highest marine traces are at c 134m, as shown on this map:


The bulk of the prominent morainic ridges are around 200m asl and above.  So there has been no further glaciation since the ice retreated from these moraines at the end of the Younger Dryas (Zone III) episode.  Traces of the highest (134m) shoreline are found on the outer or downslope flanks of these moraines. So there was no big regional ice readvance here during the Little Ice Age, as there was in the Schuchert Valley when several of the gl;aciers on the west side seem to have surged and reached advanced positions.   

In a Nov 2022 post, I suggested that the morainic ridges converging on Hjørmemoraene
might not be lateral moraines at all, but terminal moraines associated with diffluent ice spilling over from the Holger Danskes Briller trough and flowing across part of the Pythagoras Bjerg plateau:


This seems to me to be a better fit for the evidence -- but it might mean that the moraines are substantially older than the HDF "terminal moraine, and might have nothing at all to do with the Milne land Stage described by Funder, Denton and other researchers. 

More research needs to be done, but it will have to be by somebody else, since my schedule for the next few years is rather full........



  


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