The petrology, mineralogy and geochemistry of the large Fen Carbonatite Complex (Norway) REE-Nb resource

摘要

The c.580 Ma Fen Carbonatite Complex in Southern Norway is a circular, c.2.5 km diameter pipe-like composite intrusion (Figure 1) consisting of highly alkaline rocks (ijolite), carbonatites and ultramafic lampro-phyres (damtjernites). The Fen Complex is also the type area for the pervasive Na-K metasomatic alteration of country-rock gneisses referred to as 'fenitisa-tion' and it is the location where the magmatic origin of carbonatites was first proposed by Brogger in 1920s. The Fen Complex is almost certainly the largest REE resource on the European continent with a resource size estimate of >100MT at c.l wt-% REE-oxide.