Fenite

Fenite

 

a leucocratic metasomatic rock, a type of alkalic syenite. Fenites usually contain 70–90 percent alkali feldspar and 5–25 percent aegirine; alkali hornblende, sphene, and apatite are accessory minerals. Fenites sometimes contain calcite. Fenites are formed at the contacts of gneisses and granitoids with alkalic or carbonate intrusions. They may retain the banded texture of gneiss; in this case, biotite is completely replaced by alkali hornblende or aegirine. Fenites were described in the Fen area of Norway.

References in periodicals archive ?
(2000) Edgarite, Fe[Nb.sub.3][S.sub.6], first natural niobium-rich sulfide from the Khibina alkaline complex, Russian Far North: evidence for chalcophile behavior of Nb in a fenite. Contributions to Mineralogy and Petrology 138, 229-236.
NEW FIELD OBSERVATIONS ON PEGMATIC CARBONATITES, SILICQ-CARBONATITES, AND CARBONATITE-CEMENTED SODIC FENITE BRECCIAS AT OKORUSU, NAMIBIA.
NEW FIELD INTERPRTIONS OF FLUORSPAR ORE CONTROLS AT OKORUSU, NAMIBIA: REPLACEMENTS OF PEGMATITIC CARBONATITE AND FENITE BRECCIAS.