Supergene anrikninger av kopper i våre kisforekomster

Abstract

The Norwegian copper-bearing pyrite deposits generally show a higher content of copper near the surface than the average content of the whole ore body. This may be due to a secondary supergene sulphide enrichment caused by the leaching of an upper oxidized zone on the ore outcrop which later on has been removed by ice erosion during the ice age. The copper content both in the primary ore and in the enriched zones occur as chalcopyrite and it is impossible to distinguish primary and supergene chalcopyrite under the microscope. This decrease of the coppercontent in the deeper parts of the ore bodies should be considered by the valuation of new deposits of copper-bearing pyrite ores.