Geological setting of the Pb-Zn-Cu mineralization in the Mjønesfjell area Nordland, northern Norway

Abstract

The sediment Pb-Zn-Cu mineralization in the Caledonides of the Mjønesfjell area, Nordland, northern Norway has been mapped and sampled in detail as a basis for structural and geochemical studies of the mineralizations and their host rocks. The Psammitic of the Mjønesfjell area are interpretated as coastal marine deposits with placer accumulations. The stratabound mineralization is divided into 'massive sphalerite ore', 'layered sphalerite ore' and 'galena-chalcopyrite ore'. The genetic interpretation is complicated by remobilization and recrystallization, mainly during fold phases F2 and F3, but the stratabound distribution of the ore is clear. The genesis of the sulphides is syngenetic with the ore elements preci- pitating from percolating meteoric water, which probably leached the ore-brine components from the Precambrian crystalline basement. An exhalative provenance is not favoured because of the lack of volcanic rocks in the area.