TY - JOUR

T1 - Copper-containing magnesioferrite in vesicular trachyandesite in a lava tube from the 2012–2013 eruption of the tolbachik volcano, Kamchatka, Russia

AU - Sharygin, Victor V.

AU - Kamenetsky, Vadim S.

AU - Zhitova, Liudmila M.

AU - Belousov, Alexander B.

AU - Abersteiner, Adam

N1 - Publisher Copyright: © 2018 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2018/11/21

Y1 - 2018/11/21

N2 - Cu-rich magnesioferrite was found in vesicular basaltic trachyandesite in one of lava tubes (Duplex) that formed during the 2012–2013 eruption of the Tolbachik volcano, Kamchatka. This mineral is commonly associated with hematite, tenorite, halite, sylvite, and Ca-rich silicates (mainly, esseneite and Na-rich melilite) in high-temperature (800–1000◦C) reactionary zones (up to 100 µm) covering vesicular rocks and lava stalactites in the Duplex tube. The mineral relationships of this assemblage indicate the following crystallization sequence: Ca-rich silicates + hematite → Cu-rich magnesioferrite → tenorite → chlorides. This formed due to the reaction of hot gases containing Cu, alkalis, and Cl with solidified lava rock. The composition of magnesioferrite varies strongly in CuO (5.8–17.3 wt %; cuprospinel end-member—15–47 mol %), whereas the contents of other oxides are minor, indicating the main isomorphic substitution is Mg2+ ↔ Cu2+. Compositions with maximal CuO content nominally belong to Mg-rich cuprospinel: (Cu0.48Mg0.41Mn0.09Zn0.02Ca0.02) (Fe3+ 1.94Al0.03Ti0.02)O4. Increasing CuO content of the Duplex Cu-rich magnesioferrite is reflected in Raman spectra by moderate right shifting bands at ≈700–710 and 200–210 cm−1 and the appearance of an additional band at 596 cm−1 . This supports the main isomorphic scheme and may indicate a degree of inversion in the spinel structure.

AB - Cu-rich magnesioferrite was found in vesicular basaltic trachyandesite in one of lava tubes (Duplex) that formed during the 2012–2013 eruption of the Tolbachik volcano, Kamchatka. This mineral is commonly associated with hematite, tenorite, halite, sylvite, and Ca-rich silicates (mainly, esseneite and Na-rich melilite) in high-temperature (800–1000◦C) reactionary zones (up to 100 µm) covering vesicular rocks and lava stalactites in the Duplex tube. The mineral relationships of this assemblage indicate the following crystallization sequence: Ca-rich silicates + hematite → Cu-rich magnesioferrite → tenorite → chlorides. This formed due to the reaction of hot gases containing Cu, alkalis, and Cl with solidified lava rock. The composition of magnesioferrite varies strongly in CuO (5.8–17.3 wt %; cuprospinel end-member—15–47 mol %), whereas the contents of other oxides are minor, indicating the main isomorphic substitution is Mg2+ ↔ Cu2+. Compositions with maximal CuO content nominally belong to Mg-rich cuprospinel: (Cu0.48Mg0.41Mn0.09Zn0.02Ca0.02) (Fe3+ 1.94Al0.03Ti0.02)O4. Increasing CuO content of the Duplex Cu-rich magnesioferrite is reflected in Raman spectra by moderate right shifting bands at ≈700–710 and 200–210 cm−1 and the appearance of an additional band at 596 cm−1 . This supports the main isomorphic scheme and may indicate a degree of inversion in the spinel structure.

KW - Cuprospinel

KW - Hematite

KW - Kamchatka

KW - Lava tube

KW - Magnesioferrite

KW - Tenorite

KW - Tolbachik volcano

KW - Trachyandesite

KW - cuprospinel

KW - CUFE2O4

KW - GOLD

KW - MINERALS

KW - BEHAVIOR

KW - hematite

KW - lava tube

KW - FISSURE ERUPTION

KW - magnesioferrite

KW - trachyandesite

KW - PHASE-TRANSITION

KW - FUMAROLES

KW - MAGNETIC-PROPERTIES

KW - CUPROSPINEL

KW - PRECURSORS

KW - tenorite

UR - http://www.scopus.com/inward/record.url?scp=85057482117&partnerID=8YFLogxK

U2 - 10.3390/min8110514

DO - 10.3390/min8110514

M3 - Article

AN - SCOPUS:85057482117

VL - 8

JO - Minerals

JF - Minerals

SN - 2075-163X

IS - 11

M1 - 514

ER -