Journal/NDM57 2023 eng

New Data on Minerals, Volume 57, 2023

DEADLINES FOR ARTICLES

Issue 1 - March 31, 2023
Issue 2 - May 31, 2023
Issue 3 - August 31, 2023
Issue 4 - November 30, 2023

Editorial Board

Editor in Chief:
Plechov P.Yu. -D.Sc. in Geology and Mineralogy, Professor
Members of Editorial Board:
Pekov I.V. - Corresponding Member of the Russian Academy of Sciences
Garanin V.K. - D.Sc. in Geology and Mineralogy, Professor
Borutsky B.E. - D.Sc. in Geology and Mineralogy
Spiridonov B.E. - D.Sc. in Geology and Mineralogy
Chukanov N.V. - D.Sc. in Physical and Mathematical Sciences Kamenetsky V.S. - Professor (University of Tasmania)
Nenasheva S.N. - PhD in Geology and Mineralogy
Matvienko E.N. - PhD in Geology and Mineralogy
Generalov M.E. - PhD in Geology and Mineralogy
Pautov L.A. - Senior Researcher
Layout Designer
Kronrod E.V. - PhD in Chemistry

Content

Issue 1

Plechov P. Yu., Ushakova S.A., Shcherbakov V.D. Mineralogy and Genesis of Karites of the Murun Complex, p. 5-13

We studied mineralogy of the karite sample from Murun alkaline complex. Karite belongs to the silexites group and has so far been one of the few rocks of this family whose igneous genesis has not been questioned. The studied rock consists of quartz (73 vol. %), aegirine (4 vol. %), orthoclase (23 vol. %), and a number of accessory minerals, which are typical for fenites (narsarsukite, steacyite-turkestanite, delyite, etc.). Large euhedral quartz crystals with numerous oriented aegirine ingrowths create a formal resemblance to the porphyritic texture of effusive rocks, however, formation conditions of rock-forming minerals correspond to low temperature (<400℃). Possibly the rock was formed during the impregnation of a silica-rich fluid through a grorudite or aegirinite substrate. The study of karite of the Murun complex did not reveal any sign of the igneous genesis of these rocks. It can be concluded that karites, like many other representatives of the silexites family, are not magmatic, but of hydrothermal-metasomatic origin.
Keywords: Murun alkaline complex, silexites, quartz, steaciite, turkestanite, narsarsukite. читать далее...
Электронные приложения к статье : Plechov2023_Suppl.xlsx

Rumyantseva N.А., Berezin А.V., Vanshtein B.G., Skublov S.G. Clinopyroxene composition as an indicator of the conditions of crystallization of gabbroids from the Shaka Ridge (South Atlantic), p. 14-23

The paper presents the results of geochemical research (major, trace and rare earth elements) for clinopyroxene grains extracted from gabbro-type rocks of the Shaka Ridge, South Atlantic. The clinopyroxene belongs to the Ca–Mg–Fe type and is characterized by a smooth change in chemical composition from the center to the edge of the grains, expressed in a decrease in the magnesia value of Mg#, an increase in the total REE concentration and a more distinct manifestation of the negative Eu-anomaly. Based on the geochemical and morphological features of the grains, it is concluded that fractional crystallization significantly affects the composition of clinopyroxene during its formation. The estimation of P-T parameters by several methods allowed us to designate a narrow range of temperatures (1225–970 °C) and pressures (3–1 kbar) at which clinopyroxene crystallized.
Keywords: clinopyroxene, geochemistry, trace elements, REE, Shaka Ridge, South Atlantic. читать далее...

Spiridonov E.M., Devnina N.N., Murashko M.N., Korotaeva N.N., Kulikova I.M. Tungstenite and molybdenite as destruction products of ovamboite Cu20(Cu,Fe)6W2(Ge,As)6S32, tungsten-rich germanite, and maikainite Cu₂₀(Cu,Fe)₆Mo₂(Ge,As)₆S₃₂ of the Tsumeb deposit in Namibia, p. 24-29

The Vendian volcanogenic BSV type Ag-Zn-Cu-Pb Tsumeb deposit (Namibia, SW Africa) is uniquely rich in germanium minerals. Tsumeb hypothermal mineralization includes topaz, fluorapatite, quartz, K-feldspar, phlogopite, high chalcocite, pyrite, complex Ge sulphides enriched in W and Mo, namely, ovamboite Cu₂₀(Cu,Fe)₆W₂(Ge,As)₆S₃₂ and maikainite Cu₂₀(Cu,Fe)₆Мо₂(Ge,As)₆S₃₂; gallite – sphalerite – chalcopyrite solid solutions; complex Sn sulphides, such as stannoidite, and others. Tsumeb mesothermal mineralization includes chalcopyrite, chalcopyrite-bornite solid solution, bornite, high chalcocite, galena, Ga-rich sphalerite, tennantite, W-rich germanite, Zn-rich gallite, quartz, muscovite, dolomite, mawsonite, and others. Tsumeb epithermal mineralization is developed among brecciated early mineral aggregates. The parameters of formation of epithermal mineralization are T 240 – < 80 °C, solutions salinity is 6–12 wt.% equiv. NaCl. Galena, low-iron Cd sphalerite, tennantite, pyrite, low chalcocite, dolomite, and marcasite are abundant. Nonzonal, W-poor germanite, gallite, and renierite are widely developed. There are destruction products of high-temperature Ge sulphides enriched in W and Mo. The destruction products of ovamboite and W-rich germanite are abundant microveinlets and small (up to 15 µm) nests of tungstenite, low chalcocite, betechtinite, siderite, and calvertite. The destruction products of maikainite are intergrowths of the smallest molybdenite plates with low chalcocite and betechtinite. Tungstenite contains < 0.3 wt.% of Mo, molybdenite ~ 0.3 wt.% of W, which indicates their low formation temperature. The probable decomposition reaction of ovamboite (the mineral composition is close to real): Cu₂₄Fe₂W₂Ge₄As₂S₃₂ + 2 Cu₂S + 2 Pb sol. → WS₂ (tungstenite) + Cu₈WS₆ (calvertite) + Cu₂₀FePb₂S₁₅ (betechtinite) + FeS₂ (pyrite) + 4 Ge sol. + As₂S₃ sol. + 6 S sol. The probable decomposition reaction of maikainite (the mineral composition is close to real): Cu₂₄Fe₂Мо₂Ge₄As₂S₃₂ + 2 Pb sol. → 2 МоS₂ (molybdenite) + Cu₂₀FePb₂S₁₅ (betechtinite) + 2 Cu₂S (low chalcocite) + FeS₂ (pyrite) + 4 Ge sol. + 2 As₂S₃ sol.+ 3 S sol.
Keywords: tungstenite, molybdenite, calvertite, betechtinite, ovamboite, maikainite, W-rich germanite, the Tsumeb volcanogenic deposit BSV type. читать далее...

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