Geology of Finland subsequent uplift and erosion would have eroded all of these sediments. In Finland, Caledonian nappes overlie shield rocks of Archean age. Despite occurring in about the same area the Scandinavian Caledonides and the modern Scandinavian Mountains are unrelated. The ice sheet that covered Finland intermittently during the Quaternary grew out from the Scandinavian Mountains. By some estimates the Quaternary glaciers eroded away on average 25 m of rock in Finland, with the degree of erosion being highly variable. Some of the material eroded in Finland has ended up in Germany, Poland, Russia and the Baltic states. Ground till left by
Germany–Poland border Treaty of Warsaw, and by reunified Germany, in 1990 in the German–Polish Border Treaty of 1990. It was subject to minor corrections (land swaps) in 1951. The borders were partially open from 1971 to 1980, when Poles and East Germans could cross it without a passport or a visa; it was however closed again after few years, due to economic pressure on the East German economy from Polish shoppers and the desire of the East German government to diminish the influence of the Polish Solidarity movement on East Germany. Following the fall of communism in Poland and Germany, and the