The geology of the northern Sulitjelma area and its relationship to the Sulitjelma Ophiolite

The geology of the area to the north of Sulitjelma is dominated by the Skaiti Supergroup, which occurs at the top of the Upper Allochthon beneath overthrust rocks of the Uppermost Allochthon. The regional geology comprises a locally inverted, stratified ophiolite, the Sulitjelma Ophiolite, which partly intrudes the overlying rocks of the Skaiti Supergroup. These older higher grade rocks consist of a continuous 1 km thick sequence of gneisses, quartzites, semipelites, graphitic and calcareous schists, which are associated with several levels of metaigneous rocks. The most important of these are the Rupsielven Amphibolites, which are geochemically analogous to within-plate oceanic island basalts and are therefore distinct from the metabasic rocks of the Sulitjelma Ophiolite. The main period of regional deformation and metamorphism occurred during the Scandian event of the Caledonian Orogeny. Evidence is presented to show that the older metasediments and metabasites of the Supergroup retain the signature of an earlier orogenic event of possible Finnmarkian age or older. The Skaiti Supergroup therefore represents a fragment of pre-Scandian continental crust through which the ophiolitic rocks were originally intruded and onto which they were locally erupted.