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When looking at a map of Europe, I always wonder why the North-West coast of Scotland has a very similar craggy outline to the NW coast of Norway. It is completely different to the smooth outline of the Eastern coast:

enter image description here

So my question is:

What are the geological reasons for the distinctive outline of Scotland's North-West coast?

Hopefully a full explanation would include answers to the following questions:

  1. Why are they the same in Norway? (were they once joined together?)
  2. Why are they so different on the Eastern coast?
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    $\begingroup$ "were they once joined together": Norway and Scotland have been joined at their current relative positions since the Palaeozoic, although the distance between them has expanded very slightly during the Jurassic. What has happened very recently (last 10 ka or so) is that the sea level has risen, isolating the British Isles from France, and drowning "Doggerland" in the southern North Sea. $\endgroup$ – winwaed Nov 1 '16 at 19:20
  • $\begingroup$ Thank you, I should have remembered Doggerland, it was just mentioned on TV the other day. Looking up the wikipedia page reveals a graphic that may answer my question. The pack ice limit of the last ice age matches the fjord coast line of NW Scotland and Norway. Although the whole of Scotland was under ice at the time, the East coast (fjord-less) was joined to Doggerland and did not abut the sea directly. $\endgroup$ – mallardz Nov 5 '16 at 14:14
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The Northwest of Scotland has a common linkage to Norway in that both are the remains of the once-mightly Caledonide chain of mountains. This was before the Atlantic Ocean opened up, so other fragments of the Caledonides are to be found in Greenland and Eastern North America. See for example the diagrams found in Haakon's website:

http://folk.uib.no/nglhe/caledonides.html
enter image description here enter image description here

The Caledonides have a long and complex history, far too long to summarize here. Also, there has been "a lot of geology" since then, so not all of Scotland looks like all of Norway.

Another curious point to note is that the extreme northwest of Scotland has Cambrian fossils which are nothing like any you will see in the rest of Europe. They are in fact akin to North American fossils. They were an accidental 'left behind' when the Atlantic started spreading. That is when Scotland and Newfoundland were close neighbours.

Also, as TonyC points out, both Norway and Scotland (and in fact all of NW Europe, have also been sculpted by the very recent (in geological terms) glaciation.

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  • $\begingroup$ Very interesting thanks, but according to your maps, the Caledonides seem to have encompassed the entire UK, not just the NW of Scotland. This implies that the particular craggy nature of this coast and its similarity to the Norwegian coast has much more to do with the recent glaciation you also mention. It doesn't really explain why the eastern coast looks so different. This Scottish Heritage link mentions the different impact that glaciation had on the two coasts but doesn't explain why. snh.gov.uk/about-scotlands-nature/rocks-soils-and-landforms/… $\endgroup$ – mallardz Nov 5 '16 at 13:56
  • $\begingroup$ Looking up the wikipedia page of Doggerland as suggested by another comment, I found this image of recent glaciation in Europe: en.wikipedia.org/wiki/Doggerland#/media/… It shows that although the ice covered the entirety of Scotland and Scandinavia, the pack ice limit seems to fairly accurately match the coasts of the two countries that have fjords. The fjord-less East coast of Scotland abuts Doggerland and not the sea. Can this be the explanation? Does glacial erosion operate differently when glaciers run into the sea as opposed to land? $\endgroup$ – mallardz Nov 5 '16 at 14:10
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These are actually a geological feature called "fjord" which the Scandinavian Peninsula and surroundings (including Scotland) are known for. It is the result of glacial erosion during the Ice Ages. See more info here: Fjord (Wikipedia).

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  • $\begingroup$ Thanks, this is the feature that I'm talking about. Can you explain why this feature looks so similar in the NW of Scotland and the Norwegian coast, but is entirely absent on the Eastern coast? It seems so striking to me when looking at the map. This link also mentions the different effects that glaciation had in Scotland but fails to explain why:snh.gov.uk/about-scotlands-nature/rocks-soils-and-landforms/… $\endgroup$ – mallardz Nov 5 '16 at 14:00
  • $\begingroup$ Can I point you to the comment I made under Gordon's answer re Doggerland. Maybe that can explain the different results of glacial erosion on the NW and Eastern coasts of Scotland? $\endgroup$ – mallardz Nov 5 '16 at 14:15

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