Allanite-(Ce): a typical mineral of metakimberlite from the Lake Kimozero Area, Karelia

database, nuove specie, discrediti,
ridefinizioni, classificazioni, ecc.
Rispondi
Avatar utente
Marco E. Ciriotti
Messaggi: 24615
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Allanite-(Ce): a typical mineral of metakimberlite from the Lake Kimozero Area, Karelia

Messaggio da Marco E. Ciriotti » gio 15 mar, 2018 9:19

Referenza:
▪ Putintseva, E.V. & Spiridonov, E.M. (2018): [url]Allanite-(Ce): a Typical Mineral of Metakimberlite from the Lake Kimozero Area, Karelia. Geology of Ore Deposits, 59, 720-728.

Abstract:
Paleoproterozoic kimberlite from the Kimozero area in Karelia is the oldest rock of this type in Russia. It is strongly tectonized, metamorphosed, and it finally transformed into metakimberlite of the prehnite-pumpellyite facies with widespread lanthanide minerals: allanite-(Ce), bastnaesite-(Ce), bastnaesite-(La), parisite-(Ce), and monazite-(Ce). The contacts between their crystals and other metamorphic minerals, e.g., titanite, antigorite, and tremolite, are characterized by induction surfaces of concerted growth. Among lanthanide minerals, allanite-(Ce) is the most abundant. It occurs close to clinochlore pseudomorphs after phlogopite or as intergrowths with titanite in aggregates of tremolite–actinolite, calcite, and dolomite. Allanite crystals from the Kimozero area are not zonal, but vary in lanthanide contents and the Fe3+/Fe2+ ratio in grains no more than tens of microns from one another. Kimozero allanite mostly belongs to the allanite–ferriallanite series (up to 30% of ferriallanite endmember); the lesser amount corresponds to the allanite–Cr-bearing allanite series. At the late stage of metamorphism, allanite was partly replaced with parisite, bastnaesite, or monazite.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Rispondi

Chi c’è in linea

Visitano il forum: Bing [Bot] e 2 ospiti