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Wednesday, 8 May 2013

Saunders Island, NW Greenland

Enough of all that nonsense about the Stonehenge Layer.  Let's move on to something more beautiful.  This is a wonderful NASA image of Saunders Island, in Wolstenholme Fjord, south of Thule, on the NW coast of Greenland.

Click to enlarge-- there is fantastic detail on the image.

You might think that this is a wonderful image of glaciated terrain.  Think again. It's an image of an island in close proximity to the edge of the Greenland Ice Sheet, and indeed there are huge outlet glaciers draining into Wolstenholme Fjord -- but this island bears precious little evidence of glaciation.  If you look carefully you can see that the snow cover is just a seasonal one-- much of it less than a metre thick.  This is an ice-free island.  If you want to see what it looks like in the summer, use Google Earth.  Look too at the valleys -- these are fluvial valleys, with typical V-shaped cross profiles as distinct from the U-shaped cross profiles typical of glacial troughs.  This is essentially a piece of an ancient river-eroded plateau bounded by steep coastal cliffs.

The feature in the foreground is a raised marine foreland at the NE tip of the island -- you can see the steps caused by intermittent isostatic uplift since the end of the Devensian glacial stage.  I'm not sure how high the raised marine limit is in this area -- but it is probably well over 100m above present sea-level.  Back in 1962 I studied similar features in a raised delta in Kjove Land, East Greenland.  Happy days......

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