quoting Nortaneous:

Earth principles of the geologic science

ps why is it britain and who put scotland on steroids

Explanation for that geology: http://io9.com/a-fantastically-detailed-geological-history-for-game-of-1561092800

And about the similarities between Westeros and the British Isles, it's Ireland who plays a big role, at least for the central part (so it excludes the North and Dorne):