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Clinopyroxene exsolution in wollastonite from Namaqualand granulite, South Africa

  • Yusuke Seto EMAIL logo , Shugo Ohi , Norimasa Shimobayashi , Masao Kitamura , Akira Miyake , Yoshikuni Hiroi and Geoffrey H. Grantham
Published/Copyright: March 31, 2015
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American Mineralogist
From the journal American Mineralogist Volume 91 Issue 2-3

Abstract

Chemical and crystallographic properties of clinopyroxene exsolution in wollastonite are described from metamorphosed calc-silicate granulite, Namaqualand, South Africa. The wollastonite is Ca1.96Fe0.01Al0.01Si2.01-O6 belonging to space group P21/a (2M polytype) and the clinopyroxene is Ca0.99Mg0.75-0.80Fe0.17-0.21Na0.02Al0.03Si1.99-2.00O6 belonging to C2/c. An electron backscattered diffraction investigation suggests that the clinopyroxene lamellae elongated along [11̅1] lie on (120) and (100) of the wollastonite-2M, and [11̅0] of both lamellae are parallel to [001] of the wollastonite-2M. The formation of the exsolution probably results from the relatively high peak metamorphic temperature (800-860ºC) of the Namaqualand granulite and its slow cooling rate.

Keywords: Wollastonite; exsolution; clinopyroxene; TEM; EBSD
Received: 2005-8-16
Accepted: 2005-10-28
Published Online: 2015-3-31
Published in Print: 2006-2-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Presidential Address: Elastic properties of minerals and the influence of phase transitions
  2. Pressure-induced hydration in zeolite tetranatrolite
  3. Annealing experiments on induced fission tracks in apatite: Measurements of horizontal-confined track lengths and track densities in basal sections and randomly oriented grains
  4. Alpersite (Mg,Cu)SO4·7H2O, a new mineral of the melanterite group, and cuprian pentahydrite: Their occurrence within mine waste
  5. Application of a new vanadium valence oxybarometer to basaltic glasses from the Earth, Moon, and Mars
  6. Quantitative polarized infrared analysis of trace OH in populations of randomly oriented mineral grains
  7. Hydrogen incorporation in olivine from 2–12 GPa
  8. A numerical model for steady-state temperature distributions in solid-medium high-pressure cell assemblies
  9. Thermodynamics and kinetics of cation ordering in natural and synthetic Mg(Al,Fe3+)2O4 spinels from in situ high-temperature X-ray diffraction
  10. Kinetics of cation ordering in natural Mg(Al,Cr3+)2O4 spinels
  11. Equations of state and structures of andalusite to 9.8 GPa and sillimanite to 8.5 GPa
  12. Equation of state and phase transition in KAlSi3O8 hollandite at high pressure
  13. A novel arrangement of silicate tetrahedra in the uranyl silicate sheet of oursinite, (Co0.8Mg0.2)[(UO2)(SiO3OH)]2(H2O)6
  14. Aluminum substitution in stishovite and MgSiO3 perovskite: High-resolution 27Al NMR
  15. The effect of chlorine on the viscosity of Na2O-Fe2O3-Al2O3-SiO2 melts
  16. TEM imaging and analysis of microinclusions in diamonds: A close look at diamond-growing fluids
  17. A partial molar volume for ZnO in silicate melts
  18. Garnet-spinel intergrowths in ultrahigh-temperature granulite, Eastern Ghats, India: Possible evidence of an early Tschermak-rich orthopyroxene during prograde metamorphism
  19. The partial molar volume of Fe2O3 in alkali silicate melts: Evidence for an average Fe3+ coordination number near five
  20. The crystal structure of a second antigorite polysome (m = 16), by single-crystal synchrotron diffraction
  21. Oxide melt solution calorimetry of sulfides: Enthalpy of formation of sphalerite, galena, greenockite, and hawleyite
  22. An experimental determination of the effect of pressure on the Fe3+/ΣFe ratio of an anhydrous silicate melt to 3.0 GPa
  23. Evolution of product phase assemblages during thermal decomposition of muscovite under strong disequilibrium conditions
  24. Synthetic P21/m amphiboles in the system Li2O-Na2O-MgO-SiO2-H2O (LNMSH)
  25. Incongruent dissolution of wollastonite measured with vertical scanning interferometry
  26. Experiments on CaCO3-MgCO3 solid solutions at high pressure and temperature
  27. Calorimetric data for naturally occurring magnesiocarpholite and ferrocarpholite
  28. Clinopyroxene exsolution in wollastonite from Namaqualand granulite, South Africa
  29. Icosahedral coordination of phosphorus in the crystal structure of melliniite, a new phosphide mineral from the Northwest Africa 1054 acapulcoite
  30. Mechanism for the dissolution of olivine series minerals in acidic solutions
  31. High-pressure behavior of synthetic antigorite in the MgO-SiO2-H2O system from Raman spectroscopy
  32. Sinoite (Si2N2O) shocked at pressures of 28 to 64 GPa
  33. Laser Raman spectroscopic measurements of water in unexposed glass inclusions
  34. The Mars/Earth dichotomy in Mg/Si and Al/Si ratios: Is it real?
  35. Equation of state of CaIrO3-type MgSiO3 up to 144 GPa
  36. Synchrotron infrared spectroscopy of synthetic Na(NaMg)Mg5Si8O22(OH)2 up to 30 GPa: Insight on a new high-pressure amphibole polymorph
https://doi.org/10.2138/am.2006.2063
Keywords for this article
Wollastonite; exsolution; clinopyroxene; TEM; EBSD

Articles in the same Issue

  1. Presidential Address: Elastic properties of minerals and the influence of phase transitions
  2. Pressure-induced hydration in zeolite tetranatrolite
  3. Annealing experiments on induced fission tracks in apatite: Measurements of horizontal-confined track lengths and track densities in basal sections and randomly oriented grains
  4. Alpersite (Mg,Cu)SO4·7H2O, a new mineral of the melanterite group, and cuprian pentahydrite: Their occurrence within mine waste
  5. Application of a new vanadium valence oxybarometer to basaltic glasses from the Earth, Moon, and Mars
  6. Quantitative polarized infrared analysis of trace OH in populations of randomly oriented mineral grains
  7. Hydrogen incorporation in olivine from 2–12 GPa
  8. A numerical model for steady-state temperature distributions in solid-medium high-pressure cell assemblies
  9. Thermodynamics and kinetics of cation ordering in natural and synthetic Mg(Al,Fe3+)2O4 spinels from in situ high-temperature X-ray diffraction
  10. Kinetics of cation ordering in natural Mg(Al,Cr3+)2O4 spinels
  11. Equations of state and structures of andalusite to 9.8 GPa and sillimanite to 8.5 GPa
  12. Equation of state and phase transition in KAlSi3O8 hollandite at high pressure
  13. A novel arrangement of silicate tetrahedra in the uranyl silicate sheet of oursinite, (Co0.8Mg0.2)[(UO2)(SiO3OH)]2(H2O)6
  14. Aluminum substitution in stishovite and MgSiO3 perovskite: High-resolution 27Al NMR
  15. The effect of chlorine on the viscosity of Na2O-Fe2O3-Al2O3-SiO2 melts
  16. TEM imaging and analysis of microinclusions in diamonds: A close look at diamond-growing fluids
  17. A partial molar volume for ZnO in silicate melts
  18. Garnet-spinel intergrowths in ultrahigh-temperature granulite, Eastern Ghats, India: Possible evidence of an early Tschermak-rich orthopyroxene during prograde metamorphism
  19. The partial molar volume of Fe2O3 in alkali silicate melts: Evidence for an average Fe3+ coordination number near five
  20. The crystal structure of a second antigorite polysome (m = 16), by single-crystal synchrotron diffraction
  21. Oxide melt solution calorimetry of sulfides: Enthalpy of formation of sphalerite, galena, greenockite, and hawleyite
  22. An experimental determination of the effect of pressure on the Fe3+/ΣFe ratio of an anhydrous silicate melt to 3.0 GPa
  23. Evolution of product phase assemblages during thermal decomposition of muscovite under strong disequilibrium conditions
  24. Synthetic P21/m amphiboles in the system Li2O-Na2O-MgO-SiO2-H2O (LNMSH)
  25. Incongruent dissolution of wollastonite measured with vertical scanning interferometry
  26. Experiments on CaCO3-MgCO3 solid solutions at high pressure and temperature
  27. Calorimetric data for naturally occurring magnesiocarpholite and ferrocarpholite
  28. Clinopyroxene exsolution in wollastonite from Namaqualand granulite, South Africa
  29. Icosahedral coordination of phosphorus in the crystal structure of melliniite, a new phosphide mineral from the Northwest Africa 1054 acapulcoite
  30. Mechanism for the dissolution of olivine series minerals in acidic solutions
  31. High-pressure behavior of synthetic antigorite in the MgO-SiO2-H2O system from Raman spectroscopy
  32. Sinoite (Si2N2O) shocked at pressures of 28 to 64 GPa
  33. Laser Raman spectroscopic measurements of water in unexposed glass inclusions
  34. The Mars/Earth dichotomy in Mg/Si and Al/Si ratios: Is it real?
  35. Equation of state of CaIrO3-type MgSiO3 up to 144 GPa
  36. Synchrotron infrared spectroscopy of synthetic Na(NaMg)Mg5Si8O22(OH)2 up to 30 GPa: Insight on a new high-pressure amphibole polymorph
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