Tectonic stratigraphy and structural evolution of the Efjord- Sitasjaure area, northern Scandinavian Caledonides.

The Caledonian nappe complex of the Efjord-Sitasjaure area has been divided into seven tectonostratigraphic units, and is considered broadly correlative with the Sulitjelma schist-Fauske marble group sequence of the Sulitjelma area further south in Nordland, north Norway. Four phases of folding and three thrusting events have been identified. Preliminary K/Ar ages for metamorphic amphiboles and biotites range 436-463 m.y. and 369-393 m.y., respectively. Although these data are subject to multiple interpretations, probable correlations between the Efjord-Sitasjaure units and Upper Ordovician-Lower Silurian(?) rocks elsewhere in northern Norway suggest that the K/Ar ages are unreasonably old and reflect excess radiogenic Ar. -G.R.