geophase

English

Etymology

Coined by Alexander Fersman, geo- +‎ phase

Noun

geophase (plural geophases)

1. (geology) A point in the sequence of geochemical changes that occur as minerals are formed from cooling magma.
   • 2012, Robert W. Boyle, Gold: History and Genesis of Deposits‎^[1], page 108:

     […] contemporaneous with gold are gilbertite, leptochlorite, tourmaline, iron sulphides, feldspar, (rare) carbonates, and quartz; post gold minerals are quartz, zinc and lead sulphides, and many others of geophases K and L.

   • 2015, Mikhail Ostrooumov, Amazonite: Mineralogy, Crystal Chemistry, and Typomorphism‎^[2], page 179:

     In the opinion of A.E. Fersman, amazonite freely crystallizes from melt in the relatively late geophases of the pegmatite process, but the beginning of its formation belongs to the earlier and high-temperature geophase—the rise of graphic granite.