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Monday 18 July 2011

Erratic spectacle


More pictures from the Stockholm Archipelago -- these glacial erratics are sitting on "washed" surfaces of Precambrian Shield rocks, which have been eroded by aerial scouring and which have emerged from the sea in the last few centuries as a result of isostatic recovery.  The erratics are very spectacular.  In the top photo we see a jumble of erratics of various types -- there are at least five different rock types represented, each one different from the pinkish granite bedrock.  I estimate that they are up to 3 tonnes in weight.   In the bottom photo the boulders are even more obviously erratic -- grey banded schists sitting on a bright red granite bedrock.  Goodness knows how far these erratics have travelled -- maybe hundreds of kilometres, and maybe from just over the brow of the hill to the north.....

Click to enlarge the photos -- you should be able to see great detail.

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