The stratigraphy and tectonics of the Rautuvaara iron ore district, northern Finland

Abstract

The sedimentary rocks of the Rautuvaara iron ore district constitute m epicontinental association that, from oldest to youngest, comprises quartzites, quartz-feldspar schists, carbonate and skarn rocks with their associated magnetite mineralisations and amphibolites They are overlain by Kumpu-formation. The magnetite ores are strata-bound skarn ores. The Taporova hematite deposit seems to represent a different sedimentary facies. It is possible that there were at least two deformation phases in the region, the first of which was marked by the intrusion of monzonite, regional metamorphism under conditions of the amphibolite facies, the formation of skarns and the accumulation of ore material. The NE-SW trending valley of the river Äkäsjoki is marked by the presence of a prominent fault and shear zone.