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Alkali sulfates with aphthitalite-like structures from fumaroles of the Tolbachik Volcano, Kamchatka, Russia; II, A new mineral, natroaphthitalite, and new data on belomarinaite

Nadezhda V. Shchipalkina, Igor V. Pekov, Nikita V. Chukanov, Dmitry I. Belakovskiy, Natalia V. Zubkova, Natalia N. Koshlyakova, Sergey N. Britvin and Evgeny G. Sidorov
Alkali sulfates with aphthitalite-like structures from fumaroles of the Tolbachik Volcano, Kamchatka, Russia; II, A new mineral, natroaphthitalite, and new data on belomarinaite
The Canadian Mineralogist (March 2020) 58 (2): 167-181

Abstract

Natroaphthitalite K(Na,K) (sub 2) Na(SO (sub 4) ) (sub 2) , a new aphthitalite-group mineral, was found in exhalations of the active Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka Peninsula, Russia. The associated minerals are anhydrite, langbeinite, hematite, tenorite, sanidine, johillerite, tilasite, and belomarinaite. Natroaphthitalite occurs as translucent yellow to colorless roundish single-crystal individuals up to 1 cm in diameter, sometimes combined in crusts up to 2 cm across, and as aqua-transparent colorless tabular to lamellar hexagonal crystals up to 2 mm across, sometimes skeletal, typically combined in parallel intergrowths or brush-like aggregates. Dcalc is 2.664 g/cm3. Natroaphthitalite is optically uniaxial (+), omega =1.488(2), epsilon =1.490(2). The chemical composition (wt.%, electron microprobe) is: Na (sub 2) O 22.54, K (sub 2) O 26.39, SO (sub 3) 51.78, total 100.71. The empirical formula calculated based on 8 O apfu is K (sub 1.735) Na (sub 2.252) S (sub 2.002) O (sub 8) (average of 15 spot analyses). The crystal structures of natroaphthitalite and the associated aphthitalite-group mineral belomarinaite, ideally KNaSO (sub 4) , from the Arsenatnaya fumarole were solved using single-crystal X-ray diffraction and refined to R (sub 1) =0.0283 and 0.0261, respectively. The unit-cell parameters, Z, and space groups are a=5.6014(3), c=7.1507(5) Aa, V=194.30(2) Aa (super 3) , Z=1, and P3m1 for natroaphthitalite and a=5.6088(3), c=7.1858(4) Aa, V=195.77(1) Aa (super 3) , Z=2, and P3m1 for belomarinaite. The crystal chemical formulae of natroaphthitalite and belomarinaite (Z=1) are (super X) K (sub 1.00) (super Y) (Na (sub 1.28) K (sub 0.72) ) (sub Sigma 2.00) (super M) Na (sub 1.00) ( (super T) SO (sub 4) ) (sub 2) and (super X) K (sub 1.00) (super Y1) (Na (sub 0.96) K (sub 0.04) ) (sub Sigma 1.00) (super Y2) (K (sub 0.94) Na (sub 0.06) ) (sub Sigma 1.00) (super M) Na (sub 1.00) ( (super T) SO (sub 4) ) (sub 2) , respectively. Natroaphthitalite is isostructural with aphthitalite K (sub 3) Na(SO (sub 4) ) (sub 2) = (super X) K (super Y) K (sub 2) (super M) Na( (super T) SO (sub 4) ) (sub 2) (both have centrosymmetric structures) with prevailing Na over K at the Y site of the crystal structure. Belomarinaite (super X) K (super Y2) K (super Y1) Na (super M) Na( (super T) SO (sub 4) ) (sub 2) is the fully cation-ordered species, with acentric structure, in the series of natural aphthitalite-like K-Na sulfates.


ISSN: 0008-4476
EISSN: 1499-1276
Coden: CAMIA6
Serial Title: The Canadian Mineralogist
Serial Volume: 58
Serial Issue: 2
Title: Alkali sulfates with aphthitalite-like structures from fumaroles of the Tolbachik Volcano, Kamchatka, Russia; II, A new mineral, natroaphthitalite, and new data on belomarinaite
Affiliation: Moscow State University, Faculty of Geology, Moscow, Russian Federation
Pages: 167-181
Published: 202003
Text Language: English
Publisher: Mineralogical Association of Canada, Ottawa, ON, Canada
References: 35
Accession Number: 2020-041713
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 8 tables
N55°49'02" - N55°49'02", E160°22'02" - E160°22'02"
Secondary Affiliation: Russian Academy of Sciences, Institute of Problems of Chemical Physics, RUS, Russian FederationFersman Mineralogical Museum, RUS, Russian FederationSt. Petersburg State University, RUS, Russian FederationRussian Academy of Sciences, Institute of Volcanology and Seismology, RUS, Russian Federation
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Abstract, copyright, Mineralogical Association of Canada. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2020
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