On horizontal crustal strain in Finland

The part of the Baltic Shield located within Finland consists mainly of two tectonic units: the Archaean basement and the Proterozoic bedrock formed by various types of granitoids, and metamorphosed sedimentary and volcanic rocks. These are further divided into smaller subblocks. Horizontal relative movements between and within the main units have been detected by comparison of original terrestrial triangulation and repeated trilateration observations with time interval on the average 30 years (12 to 46 years). The strain pattern obtained is in agreement with geological structures as well as with a completely independently determined crustal uplift pattern.