Gasparite-(La), La(AsO4), a new mineral from Mn ores of the Ushkatyn-III deposit, Central Kazakhstan, and metamorphic rocks of the Wanni glacier, Switzerland
Détails
ID Serval
serval:BIB_4A461E0846F2
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Gasparite-(La), La(AsO4), a new mineral from Mn ores of the Ushkatyn-III deposit, Central Kazakhstan, and metamorphic rocks of the Wanni glacier, Switzerland
Périodique
American Mineralogist
ISSN
0003-004X
1945-3027
1945-3027
Statut éditorial
Publié
Date de publication
2019
Peer-reviewed
Oui
Volume
104
Pages
1469-1480
Langue
anglais
Résumé
Gasparite-(La), La(AsO4), is a new mineral (IMA 2018-079) from Mn ores of the Ushkatyn-III deposit, Central Kazakhstan (type locality) and from alpine fissures in metamorphic rocks of the Wanni glacier, Binn Valley, Switzerland (co-type locality). Gasparite-(La) is named for its dominant lanthanide, according to current nomenclature of rare-earth minerals. The occurrences and parageneses in both localities are distinct: minute isometric grains up to 15 μm in size, associated with friedelite, jacobsite, pennantite, manganhumite series minerals (alleghanyite, sonolite), sarkinite, tilasite, and retzian-(La) are typically embedded into calcite-rhodochrosite veinlets (Ushkatyn-III deposit) vs. elongated crystals up to 2 mm in size in classical alpine fissures in two-mica gneiss without indicative associated minerals (Wanni glacier). Their chemical compositions have been studied by EDX and WDX; crystal-chemical formulas of gasparite-(La) from the Ushkatyn-III deposit (holotype specimen) and Wanni glacier (co-type specimen) are (La0.65Ce0.17Nd0.07Ca0.06Mn0.05Pr0.02)1.02[(As0.70V0.28P0.02)1.00O4] and (La0.59Ce0.37Nd0.02 Ca0.02Th0.01)1.01[(As0.81P0.16Si0.02S0.02)1.01O4], respectively. In polished sections, crystals are yellow and translucent with bright submetallic luster. Selected reflectance values R1/R2 (λ, nm) for the holotype specimen in air are: 11.19/9.05 (400), 11.45/9.44 (500), 10.85/8.81 (600), 11.23/9.08 (700). The structural characteristics of gasparite-(La) were studied by means of EBSD (holotype specimen), XRD, and SREF (co-type specimen). Gasparite-(La) has a monoclinic structure with the space group P21/n. Our studies revealed that gasparite-(La) from the Ushkatyn-III deposit and Wanni glacier have different origins. La/Ce and As/P/V ratios in gasparite-(La) may be used as an indicator of formation conditions.
Mots-clé
Gasparite-(La), new mineral, arsenate, REE, Mn ores, monazite-type structure, Ushkatyn-III, Kazakhstan, Wanni glacier, Binn Valley, Switzerland
Web of science
Création de la notice
18/03/2021 13:34
Dernière modification de la notice
19/03/2021 6:26