A conglomeration of erratics

 

This is one of my favourite photos of erratics.  Erratic boulders on a glacially moulded and washed surface on Rödlöga Storskär in the Stockholm Archipelago.  Here there are 14 big boulders clustered together -- note the great variety of colours, textures and shapes.  These have come from many different provenances.  The ice was travelling directly N >> S, as indicated by abundant bedrock striations.  It's possible that there was a moraine here, but as the surface has emerged from the sea by isostatic uplift, wave action has washed away most of the finer fractions (clay, silt, sand and gravel), leaving the boulders behind.  No human intervention required..........