Ardennite-bearing mineral association related to sulfide-free ores with chalcophile metals at Nežilovo, Pelagonian Massif, North Macedonia

Bermanec, Marko and Chukanov, Nikita and Boev, Ivan and Šturman, Božidar Darko and Zebec, Vladimir and Bermanec, Vladimir (2021) Ardennite-bearing mineral association related to sulfide-free ores with chalcophile metals at Nežilovo, Pelagonian Massif, North Macedonia. Europen Journal of Mineralogy, 33. pp. 1-13. ISSN 0935-1221, e-ISSN: 1617-4011

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Abstract

Among numerous minerals determined at Nežilovo, Pelagonian Massif, North Mace donia, ardennite-(As) has been discovered in two different associations and studied by means of optical microscopy, electron microprobe analysis (EMPA), and single-crystal and powder X ray diffraction methods. The refractive indices of ardennite-(As) from Nežilovo are α = 1.537(2), β = 1.579(1) and γ = 1.741(1), where γ corresponds to the c direction. The optical axial an gle is 2Vx = 49(1)
◦. EMPA of the investigated samples yields the following empirical formulae: [Mn2+
3.27Ca0.73]64.00[Al4.18Mg1.24Fe0.29Mn3+
0.19Zn0.10]66.00(Si4.73Al0.27)65.00(As0.96Si0.03V0.01)61.00O22
[OH5.36(H2O)0.64]66.00 for ardennite-(As) and (K0.95Na0.04Ba0.02)61.01(Al1.44Fe3+
0.30Mg0.20Mn0.03Ti0.02
Zn0.01)62.00(Si3.21Al0.79O10) (OH1.97O0.03)62.00 for the associated red mica. The unit cell parameters of
ardennite-(As) determined by X-ray powder diffraction are a = 8.757(2) Å, b = 5.836(2) Å, c = 18.578(2) Å
and V = 941.97 Å3. The unit cell parameters of ardennite-(As) were also determined by single-crystal X-ray
diffraction and are a = 8.760(1) Å, b = 5.838(1) Å, c = 18.582(2) Å and V = 950.30 Å3. Regularities of isomorphism in ardennite-related minerals are discussed. The presence of ardennite-(As) in association with 2M1 and 3T phengite polytypes provides evidence for three separate stages of formation. Con ditions at which ardennite-(As) crystallized have been estimated based on compositional features of associated micas.

Item Type:	Article
Impact Factor Value:	1.578
Subjects:	Natural sciences > Earth and related environmental sciences Natural sciences > Other natural sciences
Divisions:	Faculty of Natural and Technical Sciences
Depositing User:	Biljana Kosturanova
Date Deposited:	23 Aug 2021 07:24
Last Modified:	23 Aug 2021 07:24
URI:	https://eprints.ugd.edu.mk/id/eprint/28346

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