| Summary: | The Malmberget deposit is one of the largest apatite iron ore (Kiruna type) in the world, located in northern Norrbotten, 70 km north of the article circle and this area is one of Sweden’s major ore-producing regions. The apatite iron ores in the Kiruna area occurs in an early Proterozoic continental setting. It is related to a Paleoproterozoic succession of greenstones, porphyries, and clastic metasediments that rest uncomformably upon a 2.8-2.7 Ga Archaean basement. The ore bodies are hosted by mafic to intermediate volcanic rocks and is intruded by felsic and mafic rocks. The area has experienced at least two metamorphic events: the first at 1.88 Ga and the second at 1.80 Ga. The present work is a petrochemical and structural geological study of the host rock of the Printzsköld ore body in the central part of the Malmberget deposit. The aim is to clarify if there are any petrographical and chemical differences between the footwall and the hanging wall of the Printzsköld ore body and to make clear the importance of local structural geology for the ore body geometry. Moreover it implies to identify the original character of the leptites which host the Printzsköld ore body. Seven drill cores were logged in order to outline the spatial distribution and character of rock types and the variation in alteration. Two of them have been sampled for analysis. Analytical methods that were used are whole rock geochemistry and optical microscopy. The structural geological studies were carried out both on the drill core and through underground mapping. The host rock is composed of strongly altered rock types, which are intrusive felsic rocks of aplitic and pegmatitic character, intrusive mafic rocks and extrusive mafic to intermediate metavolcanic rocks. The intrusions occur widespread both in the hanging wall and in the footwall. The common alteration minerals are biotite, albite, amphibole, K-feldspar, sericite and chlorite. Amphibole alteration strongly affects the aplites and extends into the adjacent mafic to ...
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