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  Glacial striation  
 


The following pictures show the smoothness of Scandinavian bedrock after glacial "polishing".
The scratches on the surface of the rocks were caused by stones and gravel at the bottom of the moving ice. All edges of the bedrock and all loose material were removed. When the ice melted the whole Scandinavian surface was well rounded like this.
In a plain landscape the scratches show the general direction of the movement of the glacier.
In a hilly landscape the ice flows like a viscous liquid around the rocks. Then the striation changes its direction following the shape of the surface.
    
All pictures can be enlarged (400- 500 KB each)

  
 

picture 1:
Western coast of the island of Åland.
The bedrock is Rapakivi granite. The ice moved in the line of vision.
The front of the rock is well rounded.


 picture 2:
Same situation as above. The hilly landscape forced the ice to move around the rocks.
(Campingsite at Bomarsund/Åland.)


picture 3:
Again Bomarsund/Åland.
The ice moved from right background to left foreground
The picture shows that the back of a rock was torn off by the glacier.
The surface is very smooth. When touching the rock with fingers you will feel a difference. In direction of ice movement the rock is perfectly smooth, backwards it  is a little rough.


 picture 4:
Forest at Åland.
This is an older surface, also eroded by the ice.
The islands have been lifting up since the end of the glaciation. That's why this rock came out of the sea some thousand years earlier than other parts. Due to weathering it has become rough.
Watch the red colour of the rock. It is also Rapakivi.


picture 5:
Geta / Åland:
Rocks rounded by glaciers


 picture 6:
Landscape in western Finland at the ferry from Houtskär to Mossala.
The ice moved across the dominating structures in this area. The scratches are in line of view (the big picture shows the scratches in the background).


 picture 7: The big picture shows the same without remarks.
 Close-up of a rock surface polished by ice.
The ice moved in direction to the top. The rock shows bowed pressure marks.
Picture taken at Sandö/ Åland.

picture 8
A large polished rock surface at Kökar/Åland.
The scratches are not visible because the ice moved from right to left.
The bedrock is of svecofennian age (1.7 Ga.)


picture 9:
Rounded bedrock at Salo, southwest of Finland.


picture 10:
Something special. This rock was formed first by ice and than by water.
Diabas (Dolerite) at a skerry nearby mainland Åland


 picture 11:
This picture was taken at the eastern coast of Sweden south of Västervik.
The island is called Skälö. The striation is very well preserved because of the hardness of the bedrock. (meta-sedimentary rock from Västervik)
This picture is available in larger scale.