Rare-element Pegmatite (Phosphate)

Abbreviation

REL-Li

Classification

Beryl-Columbite-Phosphate subtype < Beryl type < Lithium subclass < (LCT family) < Rare-element class < Granitic pegmatite

Required Geological Setting

Plutonic rocks

Occurrence

Pegmatites formed by fractional crystallization of S-type granite magma associated with upper Greenschist facies to Amphibolite facies in Barrovian-type middle-P metamorphism. Pegmatites are emplaced at shallow depth. Most of pegmatites are reported from active continental margin granites in compressional crustal settings such as the Pacific Ocean. Textures of host rocks are clearly cut by pegmatites, and host rocks are subjected to contact metamorphism by granites or pegmatites. Pegmatites are massive and pockets are very rare. The beryl-columbite-phosphate subtype is characterized by abundant P together with Be, Nb, and Ta.

Mineral Assemblages (Major minerals)

Quartz, Orthoclase, Microcline, Albite, Muscovite, Almandine

Mineral Assemblages

Beryl, Columbite-(Fe), Tantalite-(Fe), Triplite, Triphylite