The Proterozoic terrains of South Scandinavia and the Grenville Province
in North-America have many common features: Regional high- grade
metamorphism (Granulite-facies), anorthosites, etc. They are separated
by the Caledonian orogeny and, above all, by the Atlantic Ocean. During
the time of the great continental drift controversy, few people were
ready to admit that both sides on the Atlantic were once an unique
province. Now everybody agrees on the Post-paleozoic age of the Atlantic
and, consequently, on the intrinsic homogeneity of the much older. rocks
which occur around it. But a detailed comparison is not easy. The
Grenville Province is much larger than South Scandinavia, both regions
have been investigated by a great number of different schools, using
various methods, approaches and concepts. After several attempts, and
long discussion, it was felt by a small group of individuals, that
literature study would not be enough and that nothing could re- place
the direct contact, in the field, of specialists who had a first- hand
knowledge of all involved regions. The formula of a NATO Advanced Study
Institute, which gives a unique opportunity to meet and mix people of
various origin and levels, came almost by itself. Much work was needed,
much help has been obtained, as detailed in the "Acknowledgements".