The K<sub>2</sub>CO<sub>3</sub> fusion curve revisited: New experiments at pressures up to 12 GPa

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Author(s)

    • WANG Meili
    • Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, Peking University|School of Earth and Space Sciences, Peking University
    • LIU Qiong
    • Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, Peking University|School of Earth and Space Sciences, Peking University
    • LI Baosheng
    • School of Earth and Space Sciences, Peking University|Mineral Physics Institute, State University of New York
    • WOOD Justin
    • Mineral Physics Institute, State University of New York
    • TAO Renbiao
    • Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, Peking University|School of Earth and Space Sciences, Peking University

Abstract

<p>The melting temperatures of K<sub>2</sub>CO<sub>3</sub> were experimentally determined to be 1220 ± 20 °C (4.0 ± 0.5 GPa), 1290 ± 10 °C (9.0 ± 0.5 GPa), and 1313 ± 10 °C (11.5 ± 0.5 GPa) in a 2000 ton split–sphere apparatus and 1195 ± 15 °C (5.0 ± 0.5 GPa) in a 1000 ton uniaxial split–cylinder apparatus. The fusion curves of K<sub>2</sub>CO<sub>3</sub> were calculated up to ~ 12.0 GPa for various <i>K<sub>0</sub>′</i> (pressure dependence of bulk modulus) values of the liquid, according to the thermodynamic properties for crystalline and liquid K<sub>2</sub>CO<sub>3</sub>. On the basis of these experimental results and fusion curves of K<sub>2</sub>CO<sub>3</sub>, the <i>K<sub>0</sub>′</i> for liquid K<sub>2</sub>CO<sub>3</sub> is constrained to be ~ 14.4 ± 1.1 at pressures lower than 5.0 GPa in a third–order Birch–Murnaghan equation of state (EOS). However, the results at pressures above 9.0 GPa deviate from this trend, which suggests a possible phase transformation in either the crystalline or liquid phase of K<sub>2</sub>CO<sub>3</sub> between 5.0 and 9.0 GPa. Determination of liquid <i>K<sub>0</sub>′</i> allows the density of K<sub>2</sub>CO<sub>3</sub> liquid to be calculated to high pressure. In comparison with other common carbonates, K<sub>2</sub>CO<sub>3</sub> is shown to have the lowest melting temperature.</p>

Journal

  • Journal of Mineralogical and Petrological Sciences

    Journal of Mineralogical and Petrological Sciences 111(4), 241-251, 2016

    Japan Association of Mineralogical Sciences

Codes

  • NII Article ID (NAID)
    130005407294
  • Text Lang
    ENG
  • ISSN
    1345-6296
  • Data Source
    J-STAGE 
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