Zinc and lead deposits in the Håfjell syncline, Ofoten, northern Norway.

Abstract

This paper deals with the stratigraphic position, the tectonic development and the major mineralogy of the ores and imediate wall rocks of the Håfjell syncline, on the southern side of the Ofoten fjord, Northern Norway. Stratigraphically the ores (lead and zinc sulphide deposits) are restricted to the uppermost units of the Caledonian metasediments of the Håfjell syncline. The four units (in ascending order) Hakkelstrand limestone\/dolomite, garnet-mica schist, Djupviknes quartzite, and uppermost garnet-mica schist were mapped on the scale 1:5000. Generally the ores are strata-bound. They have been present within their wall rocks prior to the folding of the mountain range. Two fold episodes may be distinguished. The main fold axis strikes 60g East of North, plunging on average 10-15g. A crossfolding has taken place, more or less orthogonally to the above direction. It is reasonable to state that the present shape and location of the ores depend directly upon the intensity of the tectonization. A weak segregation of the main minerals has taken place during the metamorphic mobilization. The lead has been mobile in sulphidic form. Galena has been transported further than sphalerite into zones of tectonic weakness.