Origin of the high-temperature Olserum-Djupedal REE-phosphate mineralisation, SE Sweden: A unique contact metamorphic-hydrothermal system

•REE mineralisation rich in xenotime-(Y), monazite-(Ce) and fluorapatite.•The REE mineralisation shows a strong link to an 1.8 Ga alkali feldspar granite.•The REE mineralisation represents a contact metamorphic-hydrothermal system.•Formed synchronously with metasomatism in the contact aureole of the granite.•Probably forming part of a regional REE mineralising system.