Geological setting and origin of a gold-mineralized zone at Myrefjellet, Mauken, Troms

Abstract

In 2008 Scandinavian Highlands discovered a gold mineralization within the Mauken basement window. The Mauken basement window is a thought to be an eastward continuation of the West Troms Basement Complex which is a series of rocks with an age span from Neoarchaean to Paleoproterozic. The mineralization found in a steeply dipping NW-SE striking shear zone and is hosted in a meta-sedimentary unit. The rock which hosts the mineralization is metamorphosed under greenschist facies conditions. The protolith for the mineralization has not been determined and could be of magmatic or of sedimentary origin, which the rocks surrounding the mineralization are. Surrounding the mineralization is a halo of sericitization, but the rock is also influenced by chloritization and local carbonatization. The mineral assemblage of the mineralization is dominated by quartz, micas, and carbonates. The gold mineralization is closely linked to the formation of arsenopyrite, since most of the gold is found as inclusions in arsenopyrite grains. The deposit is likely to have been formed in relation to the Svecofennian orogeny and could be classified as an orogenic gold deposit.