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Coesite exsolution from supersilicic titanite in UHP marble from the Kokchetav Massif, northern Kazakhstan

  • Yoshihide Ogasawara EMAIL logo , Kyoka Fukasawa and Shigenori Maruyama
Published/Copyright: March 28, 2015
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American Mineralogist
From the journal American Mineralogist Volume 87 Issue 4

Abstract

Coesite exsolved from supersilicic titanite was discovered in an impure calcite marble at Kumdykol in the Kokchetav UHP (ultrahigh-pressure) metamorphic terrane, northern Kazakhstan. This impure marble consists mainly of calcite, K-feldspar, diopside, and symplectites of diopside + zoisite, with minor amount of titanite, phengite, and garnet. No diamond was found in the marble. Coesite and quartz, which have needle or platy shapes measuring about 20-60 mm in length, occur as major exsolved phases in the cores and mantles of titanite crystals with minor calcite and apatite. The strongest Raman band for the coesite needles and plates was confirmed at about 524 cm-1 with a weak band at about 271 cm-1. To estimate the initial composition of the titanite before coesite exsolution, exsolved phases were reintegrated by measuring their area fractions on digital images. The highest excess Si in titanite was thus determined to be 0.145 atoms per formula unit (apfu). This composition requires a pressure higher than 6 GPa on the basis of phase relations in the system CaTiSiO5-CaSi2O5. This pressure is consistent with other evidence of high pressure in the same marble, such as 1.4-1.8 wt% K2O and over 1000 ppm H2O in diopside. Supersilicic titanite and coesite exsolution also indicate that SiO2 exsolution occurred in the coesite stability field during exhumation of the UHP metamorphic unit.

Received: 2001-5-2
Accepted: 2001-12-4
Published Online: 2015-3-28
Published in Print: 2002-4-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Titanium in biotite from metapelitic rocks: Temperature effects, crystal-chemical controls, and petrologic applications
  2. Local equilibrium in polymetamorphic gneiss and the titanium substitution in biotite
  3. The enthalpy of formation and internally consistent thermodynamic data of Mg-staurolite
  4. Coexisting andalusite, kyanite, and sillimanite: Sequential formation of three Al2SiO5 polymorphs during progressive metamorphism near the triple point, Sivrihisar, Turkey
  5. Co-existing aluminum silicates in quartz veins: A quantitative approach for determining andalusite-sillimanite equilibrium in natural samples using oxygen isotopes
  6. Stability of corundum + quartz relative to kyanite and sillimanite at high temperature and pressure
  7. Andalusite-sillimanite replacement (Mazarrón, SE Spain): A microstructural and TEM study
  8. Hydroxyl-rich topaz in high-pressure and ultrahigh-pressure kyanite quartzites, with retrograde woodhouseite, from the Sulu terrane, eastern China
  9. Coesite exsolution from supersilicic titanite in UHP marble from the Kokchetav Massif, northern Kazakhstan
  10. Composition of synthetic tremolite-tschermakite solid solutions in amphibole + anorthiteand amphibole + zoisite-bearing assemblages
  11. Paragenesis and thermobarometry of Ca-amphiboles in the Barcroft granodioritic pluton, central White Mountains, eastern California
  12. B and Li in Proterozoic metapelites from the Black Hills, U.S.A.: Implications for the origin of leucogranitic magmas
  13. The role of Fe and cation order in the crystal chemistry of surinamite, (Mg,Fe2+)3(Al,Fe3+)3O[AlBeSi3O15]: A crystal structure, Mössbauer spectroscopic, and optical spectroscopic study
  14. Fe3+ and Fe2+ partitioning among silicates in metapelites: A synchrotron micro-XANES study
  15. Thermodynamic and structural behavior of analcime–leucite analogue systems
  16. In-situ synchrotron study of the kinetics, thermodynamics, and reaction mechanisms of the hydrothermal crystallization of gyrolite, Ca16Si24O60(OH)8·14H2O
  17. The crystal structures of grossular and spessartine between 100 and 600 K and the crystal chemistry of grossular-spessartine solid solutions
  18. The structures of becquerelite and Sr-exchanged becquerelite
  19. Elasticity and equation of state of orthoenstatite, MgSiO3
  20. Reidite: An impact-produced high-pressure polymorph of zircon found in marine sediments
  21. A new polymorph of eucryptite (LiAlSiO4), ε-eucryptite, and thermal expansion of α- and ε-eucryptite at high pressure
  22. Disordering during melting: An 17O NMR Study of crystalline and glassy CaTiSiO5 (titanite)
  23. Characterization of Mn oxides in cemented streambed crusts from Pinal Creek, Arizona, U.S.A., and in hot-spring deposits from Yuno-Taki Falls, Hokkaido, Japan
https://doi.org/10.2138/am-2002-0409

Articles in the same Issue

  1. Titanium in biotite from metapelitic rocks: Temperature effects, crystal-chemical controls, and petrologic applications
  2. Local equilibrium in polymetamorphic gneiss and the titanium substitution in biotite
  3. The enthalpy of formation and internally consistent thermodynamic data of Mg-staurolite
  4. Coexisting andalusite, kyanite, and sillimanite: Sequential formation of three Al2SiO5 polymorphs during progressive metamorphism near the triple point, Sivrihisar, Turkey
  5. Co-existing aluminum silicates in quartz veins: A quantitative approach for determining andalusite-sillimanite equilibrium in natural samples using oxygen isotopes
  6. Stability of corundum + quartz relative to kyanite and sillimanite at high temperature and pressure
  7. Andalusite-sillimanite replacement (Mazarrón, SE Spain): A microstructural and TEM study
  8. Hydroxyl-rich topaz in high-pressure and ultrahigh-pressure kyanite quartzites, with retrograde woodhouseite, from the Sulu terrane, eastern China
  9. Coesite exsolution from supersilicic titanite in UHP marble from the Kokchetav Massif, northern Kazakhstan
  10. Composition of synthetic tremolite-tschermakite solid solutions in amphibole + anorthiteand amphibole + zoisite-bearing assemblages
  11. Paragenesis and thermobarometry of Ca-amphiboles in the Barcroft granodioritic pluton, central White Mountains, eastern California
  12. B and Li in Proterozoic metapelites from the Black Hills, U.S.A.: Implications for the origin of leucogranitic magmas
  13. The role of Fe and cation order in the crystal chemistry of surinamite, (Mg,Fe2+)3(Al,Fe3+)3O[AlBeSi3O15]: A crystal structure, Mössbauer spectroscopic, and optical spectroscopic study
  14. Fe3+ and Fe2+ partitioning among silicates in metapelites: A synchrotron micro-XANES study
  15. Thermodynamic and structural behavior of analcime–leucite analogue systems
  16. In-situ synchrotron study of the kinetics, thermodynamics, and reaction mechanisms of the hydrothermal crystallization of gyrolite, Ca16Si24O60(OH)8·14H2O
  17. The crystal structures of grossular and spessartine between 100 and 600 K and the crystal chemistry of grossular-spessartine solid solutions
  18. The structures of becquerelite and Sr-exchanged becquerelite
  19. Elasticity and equation of state of orthoenstatite, MgSiO3
  20. Reidite: An impact-produced high-pressure polymorph of zircon found in marine sediments
  21. A new polymorph of eucryptite (LiAlSiO4), ε-eucryptite, and thermal expansion of α- and ε-eucryptite at high pressure
  22. Disordering during melting: An 17O NMR Study of crystalline and glassy CaTiSiO5 (titanite)
  23. Characterization of Mn oxides in cemented streambed crusts from Pinal Creek, Arizona, U.S.A., and in hot-spring deposits from Yuno-Taki Falls, Hokkaido, Japan
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