B. Lundberg and J. Smellie
Painirova and Mertainen iron ores; two deposits of the Kiruna iron ore type in northern Sweden (in A special issue devoted to mineral deposits in Fennoscandia)
Economic Geology and the Bulletin of the Society of Economic Geologists (August 1979), 74(5):1131-1152

Abstract:
Apatite iron ores of the Kiruna type have been described from Painirova and Mertainen in northern Sweden. It is considered important that the ores are associated with volcanic rocks of a particular composition, i.e., iron-rich trachytes, which do not form part of a magmatic differentiation series. It is suggested that such a trachyte has been formed from the assimilation of iron-rich material during its formation. The ore, mostly in the form of magnetite, occurs in the host trachytes as disseminations, coarse aggregates, globular and spherical concentrations, and as a fracture infilling component. It is thought possible that the iron ores are the result of immiscibility aided by a high volatile content. The associated widespread brecciation in Painirova and Mertainen may have been caused by the mechanical effect of the iron-rich fluids in a differential stress field during consolidation of the trachyte.