Geology of the protogine zone south of Lake Vättern, southern Sweden : a reinterpretation
Abstract Influential models describe the Protogine Zone (PZ) as a collisional suture and thrust front and, in particular, as the extension of the Grenvillian thrust front into Scandinavia. These models do not consider the significance of a rich variety of geological features related to Late Riphean-Vendian rifting of the craton. This paper calls attention to steep, northerly trending and anastomosing, narrow deformation zones of ductile or brittle-ductile character. The zones can be mapped out into the Vattern Graben of c. 700–800 Ma age. Uplift of southwestern Sweden after c. 910 Ma must have had a profound tectonic influence on the bedrock along the PZ. The effects of this late deformation must be identified and subtracted from the structural record before the significance of Sveconorwegian-Grenvillian deformation can be assessed. There is no other foliation south of Lake Vattern qualifying for the name “protogine zone foliation”. Rift-related magmatic and metallogenic features are remarkably restricted...