Fumarolic arsenates − a special type of arsenic mineralization

Pekov, Igor V.; Koshlyakova, Natalia N.; Zubkova, Natalia V.; Lykova, Inna S.; Britvin, Sergey N.; Yapaskurt, Vasiliy O.; Agakhanov, Atali A.; Shchipalkina, Nadezhda V.; Turchkova, Anna G.; Sidorov, Evgeny G.

doi:10.1127/ejm/2018/0030-2718

Cited by 80 publications

(75 citation statements)

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“…The Arsenatnaya fumarole was uncovered and first studied by us during fieldworks in July 2012. This active fumarole described in papers [18,19] is a near-meridional linear system of mineralized pockets (up to 10-15 cm wide) and cracks situated between blocks of basalt scoria and volcanic bombs in the near-surface part of the scoria cone. The length of the hot area belonging to Arsenatnaya is about 15 m and its width varies from 1-1.5 m in the southern end to 3-4 m in the northern part.…”

Section: Occurrence and Mineral Associationsmentioning

confidence: 99%

Copper in Natural Oxide Spinels: The New Mineral Thermaerogenite CuAl2O4, Cuprospinel and Cu-Enriched Varieties of Other Spinel-Group Members from Fumaroles of the Tolbachik Volcano, Kamchatka, Russia

et al. 2018

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This paper is the first description of natural copper-rich oxide spinels. They were found in deposits of oxidizing-type fumaroles related to the Tolbachik volcano, Kamchatka, Russia. This mineralization is represented by nine species with the following maximum contents of CuO (wt.%, given in parentheses): a new mineral thermaerogenite, ideally CuAl2O4 (26.9), cuprospinel, ideally CuFe3+2O4 (28.6), gahnite (21.4), magnesioferrite (14.7), spinel (10.9), magnesiochromite (9.0), franklinite (7.9), chromite (5.9), and zincochromite (4.8). Cuprospinel, formerly known only as a phase of anthropogenic origin, turned out to be the Cu-richest natural spinel-type oxide [sample with the composition (Cu0.831Zn0.100Mg0.043Ni0.022)Σ0.996(Fe3+1.725Al0.219Mn3+0.048Ti0.008)Σ2.000O4 from Tolbachik]. Aluminum and Fe3+-dominant spinels (thermaerogenite, gahnite, spinel, cuprospinel, franklinite, and magnesioferrite) were deposited directly from hot gas as volcanic sublimates. The most probable temperature interval of their crystallization is 600–800 °C. They are associated with each other and with tenorite, hematite, orthoclase, fluorophlogopite, langbeinite, calciolangbeinite, aphthitalite, anhydrite, fluoborite, sylvite, halite, pseudobrookite, urusovite, johillerite, ericlaxmanite, tilasite, etc. Cu-bearing spinels are among the latest minerals of this assemblage: they occur in cavities and overgrow even alkaline sulfates. Cu-enriched varieties of chrome-spinels (magnesiochromite, chromite, and zincochromite) were likely formed in the course of the metasomatic replacement of a magmatic chrome-spinel in micro-xenoliths of ultrabasic rock under the influence of volcanic gases. The new mineral thermaerogenite, ideally CuAl2O4, was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption. It forms octahedral crystals up to 0.02 mm typically combined in open-work clusters up to 1 mm across. Thermaerogenite is semitransparent to transparent, with a strong vitreous lustre. Its colour is brown, yellow-brown, red-brown, brown-yellow or brown-red. The mineral is brittle, with the conchoidal fracture, cleavage is none observed. D(calc.) is 4.87 g/cm3. The chemical composition of the holotype (wt.%, electron microprobe) is: CuO 25.01, ZnO 17.45, Al2O3 39.43, Cr2O3 0.27, Fe2O3 17.96, total 100.12 wt.%. The empirical formula calculated on the basis of 4 O apfu is: (Cu0.619Zn0.422)Σ1.041(Al1.523Fe3+0.443Cr0.007)Σ1.973O4. The mineral is cubic, Fd-3m, a = 8.093(9) Å, V = 530.1(10) Å3. Thermaerogenite forms a continuous isomorphous series with gahnite. The strongest lines of the powder X-ray diffraction pattern of thermaerogenite [d, Å (I, %) (hkl)] are: 2.873 (65) (220), 2.451 (100) (311), 2.033 (10) (400), 1.660 (16) (422), 1.565 (28) (511) and 1.438 (30) (440).

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Section: Occurrence and Mineral Associationsmentioning

confidence: 99%

Copper in Natural Oxide Spinels: The New Mineral Thermaerogenite CuAl2O4, Cuprospinel and Cu-Enriched Varieties of Other Spinel-Group Members from Fumaroles of the Tolbachik Volcano, Kamchatka, Russia

et al. 2018

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“…Two new mineral species, arsmirandite and lehmannite, have been found in the active Arsenatnaya fumarole 29,30 located at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption 1975-1976, Tolbachik volcano, Kamchatka Peninsula, Far-Eastern Region, Russia (55°41′N 160°14′E, 1200 m asl). The mineral assemblages encasing these halide-arsenates were formed in the temperature range between 500 and 700 °C 22,30 and were located inside the fumarole. The detailed mineralogical description of the minerals will be given elsewhere.…”

Section: Resultsmentioning

confidence: 99%

Polyoxometalate chemistry at volcanoes: discovery of a novel class of polyoxocuprate nanoclusters in fumarolic minerals

Britvin

Pekov

Yapaskurt

et al. 2020

Sci Rep

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Polyoxometalate (POM) chemistry is an important avenue of comprehensive chemical research, due to the broad chemical, topological and structural variations of multinuclear polyoxoanions that result in advanced functionality of their derivatives. the majority of compounds in the polyoxometalate kingdom are synthesized under laboratory conditions. However, Nature has its own labs with the conditions often unconceivable to the mankind. The striking example of such a unique environment is volcanic fumaroles-the natural factories of gas-transport synthesis. We herein report on the discovery of a novel class of complex polyoxocuprates grown in the hot active fumaroles of the Tolbachik volcano at the Kamchatka Peninsula, Russia. The cuboctahedral nanoclusters {[Mcu 12 o 8 ](AsO 4) 8 } are stabilized by the core Fe(III) or Ti(IV) cations residing in the unique cubic coordination. The nanoclusters are uniformly dispersed over the anion-and cation-deficient NaCl matrix. Our discovery might have promising implications for synthetic chemistry, indicating the possibility of preparation of complex polyoxocuprates by chemical vapor transport (CVT) techniques that emulate formation of minerals in high-temperature volcanic fumaroles. Polyoxometalates (POMs) constitute a large group of materials with discrete metal-anion clusters of various shapes and sizes 1-3. Traditionally, POMs were associated with d-block metals in high oxidation states (V 5+ , Nb 5+ , Ta 5+ , Mo 6+ and W 6+), but recent studies extended the field to other elements such as actinides 4 and noble metals 5. In 1990, Achim Müller and co-workers 6 introduced the term 'polyoxocuprates' (POCus) to identify clusters formed by polymerization of Cu coordination polyhedra, previously reported for synthetic inorganic compounds such as Ba 44 Cu 45 O 87 Cl 4 and Ba 88 Cu 88 O 175 Br 2

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“…Articles submitted to the Special Issue of Minerals effectively demonstrate the great chemical, structural and genetic diversity of new mineral species of the present time, as well as the geography of discoveries and the variety of analytical methods used in studies of new minerals. Recently an increasing number of new mineral species discovered in volcanic fumaroles has been observed [1]. In the present issue, there are two articles devoted to the two new volcanic minerals: Verneite, Na 2 Ca 3 Al 2 F 14 , described simultaneously from Eldfell and Hekla volcanoes in Iceland and Vesuvius in Italy [2], and thermaerogenite, CuAl 2 O 4 , from the Tolbachik volcano at Kamchatka, Russia [3].…”

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confidence: 91%