Baltic Shield

The Baltic Shield, also known as the Fennoscandian Shield, is a segment of the East European Craton spanning Fennoscandia, northwestern Russia and the northern Baltic Sea, built from Archean and Proterozoic gneiss and greenstone that has undergone extensive tectonic deformation. It carries the oldest rock on the European continent, with a crust some 250 to 300 kilometers thick; the Karelian, Belomorian and Kola provinces hold the oldest material, dated to 3,100 to 2,500 million years ago, while the youngest rock, in the Sveconorwegian province, dates to 1,700 to 900 million years ago. The shield grew through successive collisions with neighboring crustal fragments that once raised mountains of their own; those mountains have long since eroded away, and Pleistocene glaciation scoured the region clean of later sediment, leaving a largely flat landscape of exposed basement rock valued for studying the deep geological history of eastern Europe. This entity documents the Baltic Shield specifically as a geological formation.