Tectonostratigraphy and Caledonian structure of the Singis-Tjuoltajaure area, central Norrbotten Caledonides, Sweden

Abstract

Abstract The Singis-Tjuoltajaure area of the central Norrbotten Caledonides allows examination of the rocks of the Lower Köli Nappe, Seve Nappe, Middle Allochthon, and the Autochthon-Parautochthon. In this study the rocks of the area are grouped into a specific tectonostratigraphy and described and then regional correlations and implications are discussed. The deformational history of the Singis-Tjuoltajaure region may be subdivided into eight deformational events which are associated with two major tectonothermal events. Deformations 1 and 2 are Finnmarkian, and are associated with the Late Cambrian to Early Ordovician metamorphism of the Seve Nappe. Deformation 3 is associated with the post-Ashgillian Scandian metamorphism of the Lower Köli Nappe. The juxtaposition of the Köli and Seve produced the fabrics associated with the fourth deformational event. Emplacement of the Upper Nappe Complex onto the rocks of the Baltic Shield produced structures assigned to D5, D6, and D7. The final deformational event (D8) is correlated with late stage west-vergent motion along the Seve—Köli contact.