Orsa, Sweden thousands of visitors and the inhabitants of Orsa. The big forests start just north of the town of Orsa, with the sparsely populated Orsa finnmark, to which many Finns emigrated during the 17th century. About 500 people speak the Orsamål dialect, an Old Scandinavian language, which is a variant of Dalecarlian, also called Old Swedish in Minnesota, USA. Orsa is twinned with: Orsa, Sweden Orsa is a locality and the seat of Orsa Municipality, Dalarna County, Sweden, with 5,308 inhabitants (2010). It is located in the northern part of lake Siljan, about north of the town Mora. Inlandsbanan and European
Siljan Ring an annular outcrop of Lower Paleozoic sedimentary rocks within Proterozoic granites of the Dala series. In Dalarna, the basement rocks consist of granites dated as 1.6 billion years old, putting them at the boundary between the Paleoproterozoic and the Mesoproterozoic. They were emplaced shortly after the Svecokarelian orogeny. The oldest sedimentary rocks that outcrop in the Siljan area are of Ordovician age. The sequence is dominated by limestone formations with one prominent black shale, the Fjäcka Shale, which is bituminous and has generated petroleum, sourcing the oil found in limestone cavities in the same area. The Ordovician sequence is overlain