Rare-element Pegmatite (Elbaite)

Abbreviation

REL-Li

Classification

Elbaite subtype < Complex 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. It is considered that the complex type pegmatites are formed by extremely fractionated magma. Rare-element class pegmatites are considered to be 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 rich in miarolitic cavities. The lepidolite subtype is characterized by abundant B, and rich in elbaite and little lepidolite (polylithionite) as Li-bearing aluminosilicate. The elbaite subtype may be transitional to the lepidolite subtype.

Mineral Assemblages (Major minerals)

Quartz, Orthoclase, Microcline, Albite, Muscovite, (Almandine)

Mineral Assemblages

Elbaite, Hambergite, Danburite, Datolite, Microlite, (Polylithionite)