Characterisation of iron mineralisations of Kiruna type in the Kiruna area, northern Sweden

摘要

Apatite iron ore is an economically important type of deposit in the Northern Norrbotten ore province in northern Sweden. It is suggested to represent an Fe-dominated end-member of the Fe-oxide Cu-Au class of mineral deposits and occur together with Cu-Au deposits in their type area at Kiruna. They show a large variation in host rock composition, host rock relationship, alteration, P content, geochemistry, and associated minor components. Sulphides are mostly scarce but may be enriched in some deposits. Average Cu and Au contents are mostly less than 100 and 0.01 ppm, respectively. The ores are enriched in V and to various degree in REE, Ti, Nb and Th. Most features of the apatite iron ores in Northern Norrbotten are compatible with either a magmatic intrusive origin or a hydrothermal origin. Probably both magmatic and hydrothermal processes have been active explaining the large variation in mineralisation style recognised within and between individual deposits.