About classification of granite pegmatites and pegmatite-bearing granitesystems
Beskin S. M., Marin Yu. B.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2017. V. 146. N 6. P. 1-17
Full text is available
Language: Russian
Abstract
This article discusses and clarifies the concepts of pegmatite rocks, pegmatite and pegmatoid bodies, the classification of granite pegmatites and their relation to various types of granites. It is suggested to distinguish the following six types of pegmatite-bearing granite systems (PGS): I—PGS is represented by ranges of granitoid series of normal alkalinity in the form of central-type plutons, with chamber pegmatites, rare-metal lithium-fluoride granites and pegmatoids in virtually unmetamorphosed sequences (Zhanchivlan, Dzunbain, Goriho, Mongolia; Adun-Chelon, Sokhondo-Ugdyri, Transbaikalia) formed at low pressure in the absence of high alkalinity signs of subsynchronous granitoids; II — PGS is represented by central-type granitoid plutons with increased alkalinity, with chamber pegmatites (sometimes with Y-REE mineralization), rare-metal and rare-earth alkali granites and pegmatoids in unmetamorphosed sequences (Akzhaylyau, Zerenda, Bayanaul, Kent, Kazakhstan; Korosten, Ukraine; Pikes Peak Mount Princeton, USA; Ulkan, Ingur, Russia; Strange Lake, Canada; Haldzan-Buregte, Khan-Bogdo, Mongolia) also formed at low pressure; III—PGS is represented by dyke fields, flats and stocks of low alkali granitoids, with rare-metal pegmatites, rare-metal albite and spodumene-albite granites, their pegmatoids and complex rare-metal pegmatites in the metamorphic formations of greenschist and epidote-amphibolite facies (Koktogay, China; Bernic Lake, Canada; Bikita, Zimbabwe, Karibib, Namibia; Vishnyakovskoe, Russia), which corresponds to the average pressure conditions of the pegmatite formation; IV—PGS is represented by dyke fields, flats and stocks of high-alkali granitoids, with rare-metal and rare-earth pegmatites within the epidote-amphibolite metamorphic facies (Ilmensky Mountains, Ural; Western Caves, Kola Peninsula; Slyudyanka-2, Abchad, Olkhon region) formed at average pressure; V — PGS is represented by dyke fields, flats and stocks of low-alkali granitoids, with mica-bearing and muscovite-rare-metal pegmatites in the zones of kyanite-sillimanite type of amphibolite metamorphic facies (North Karelia, Eastern Siberia, etc.) formed at high pressure; VI — PGS is represented by dyke fields, flats, and stocks of synorogenic granite migmatites of the high-alkali potassium series, with ceramic and uranium-rare-earth pegmatites in metamorphic stratas of amphibolite and granulite facies (Northen Ladoga Region, Pobuzhye, etc.) formed at high pressure.
Key words: granite pegmatites and pegmatoids, classification of pegmatites, amazonite pegmatites, albite-spodumene granites, pegmatite-bearing granite systems.
