Melting and subsolidus phase relations in the system Na2CO 3-MgCO3±H2O at 6 GPa and the stability of Na2Mg(CO3)2 in the upper mantle

Anton Shatskiy; Pavel N. Gavryushkin; Igor S. Sharygin; Konstantin D. Litasov; Igor N. Kupriyanov; Yuji Higo; Yuri M. Borzdov; Ken Ichi Funakoshi; Yuri N. Palyanov; Eiji Ohtani

doi:10.2138/am.2013.4418

Melting and subsolidus phase relations in the system Na₂CO ₃-MgCO₃±H2O at 6 GPa and the stability of Na2Mg(CO3)2 in the upper mantle

Anton Shatskiy, Pavel N. Gavryushkin, Igor S. Sharygin, Konstantin D. Litasov, Igor N. Kupriyanov, Yuji Higo, Yuri M. Borzdov, Ken Ichi Funakoshi, Yuri N. Palyanov, Eiji Ohtani

Research output: Contribution to journal › Article › peer-review

36 Citations (Scopus)

Abstract

Phase relations in the Na₂CO₃-MgCO₃ system have been studied in high-pressure high-temperature (HPHT) multi-anvil experiments using graphite capsules at 6.0 ± 0.5 GPa pressures and 900-1400 °C temperatures. Sub-solidus assemblages are represented by Na ₂CO₃+Na₂Mg(CO₃)₂ and Na₂CO₃+Na₂Mg(CO₃) ₂+MgCO₃ with the transition boundary near 50 mol% MgCO₃ in the system. The Na₂CO₃-Na ₂CO₃+Na₂Mg(CO₃)₂ eutectic is established at 1200 °C and 29 mol% MgCO₃. Melting of Na ₂CO₃ occurs between 1350 and 1400 °C. We propose that Na₂CO₃+Na₂Mg(CO₃)₂ disappears between 1200 and 1250 °C via congruent melting. Magnesite remains as a liquidus phase above 1300 °C. Measurable amounts of Mg in Na ₂CO₃ suggest an existence of MgCO₃ solid-solutions in Na₂CO₃ at given experimental conditions. The maximum MgCO₃ solubility in Na-carbonate of about 9 mol% was established at 1100 and 1200 °C. The Na₂CO₃ and Na₂CO₃+Na₂Mg(CO₃)₂ compounds have been studied using in situ X-ray coupled with a DIA-type multi-anvil apparatus. The studies showed that eitelite is a stable polymorph of Na₂CO₃+Na₂Mg(CO₃)₂ at least up to 6.6 GPa and 1000 °C. In contrast, natrite, γ-Na ₂CO₃, is not stable at high pressure and is replaced by β-Na₂CO₃. The latter was found to be stable at pressures up to 11.7 GPa at 27 °C and up to 15.2 GPa at 1200 °C and temperatures at least up to 800 °C at 2.5 GPa and up to 1000 °C at 6.4 GPa. The X-ray and Raman study of recovered samples showed that, under ambient conditions, β-Na₂CO₃ transforms back to γ-Na₂CO₃. Eitelite [Na₂CO ₃+Na₂Mg(CO₃)₂] would be an important mineral controlling insipient melting in subducting slab and upwelling mantle. At 6 GPa, melting of the Na₂CO₃+Na₂Mg(CO ₃)₂+MgCO₃ assemblage can be initiated, either by heating to 1300 °C under "dry" conditions or at 900-1100 °C under hydrous conditions. Thus, the Na₂CO₃+Na ₂Mg(CO₃)₂ could control the solidus temperature of the carbonated mantle under "dry" conditions and cause formation of the Na- and Mg-rich carbonatite melts similar to those found as inclusions in olivines from kimberlites and the deepest known mantle rock samples-sheared peridotite xenoliths (190-230 km depth).

Original language	English
Pages (from-to)	2172-2182
Number of pages	11
Journal	American Mineralogist
Volume	98
Issue number	11-12
DOIs	https://doi.org/10.2138/am.2013.4418
Publication status	Published - 2013
Externally published	Yes

Keywords

Alkaline carbonates
Earth's mantle
Eitelite
High-pressure experiment
In situ X-ray diffraction
Natrite
Raman

ASJC Scopus subject areas

Geophysics
Geochemistry and Petrology

Access to Document

10.2138/am.2013.4418

Cite this

Shatskiy, A., Gavryushkin, P. N., Sharygin, I. S., Litasov, K. D., Kupriyanov, I. N., Higo, Y., Borzdov, Y. M., Funakoshi, K. I., Palyanov, Y. N., & Ohtani, E. (2013). Melting and subsolidus phase relations in the system Na₂CO ₃-MgCO₃±H2O at 6 GPa and the stability of Na2Mg(CO3)2 in the upper mantle. American Mineralogist, 98(11-12), 2172-2182. https://doi.org/10.2138/am.2013.4418

Melting and subsolidus phase relations in the system Na₂CO ₃-MgCO₃±H2O at 6 GPa and the stability of Na2Mg(CO3)2 in the upper mantle. / Shatskiy, Anton; Gavryushkin, Pavel N.; Sharygin, Igor S.; Litasov, Konstantin D.; Kupriyanov, Igor N.; Higo, Yuji; Borzdov, Yuri M.; Funakoshi, Ken Ichi; Palyanov, Yuri N.; Ohtani, Eiji.

In: American Mineralogist, Vol. 98, No. 11-12, 2013, p. 2172-2182.

Research output: Contribution to journal › Article › peer-review

Shatskiy, A, Gavryushkin, PN, Sharygin, IS, Litasov, KD, Kupriyanov, IN, Higo, Y, Borzdov, YM, Funakoshi, KI, Palyanov, YN & Ohtani, E 2013, 'Melting and subsolidus phase relations in the system Na₂CO ₃-MgCO₃±H2O at 6 GPa and the stability of Na2Mg(CO3)2 in the upper mantle', American Mineralogist, vol. 98, no. 11-12, pp. 2172-2182. https://doi.org/10.2138/am.2013.4418

Shatskiy, Anton ; Gavryushkin, Pavel N. ; Sharygin, Igor S. ; Litasov, Konstantin D. ; Kupriyanov, Igor N. ; Higo, Yuji ; Borzdov, Yuri M. ; Funakoshi, Ken Ichi ; Palyanov, Yuri N. ; Ohtani, Eiji. / Melting and subsolidus phase relations in the system Na₂CO ₃-MgCO₃±H2O at 6 GPa and the stability of Na2Mg(CO3)2 in the upper mantle. In: American Mineralogist. 2013 ; Vol. 98, No. 11-12. pp. 2172-2182.

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title = "Melting and subsolidus phase relations in the system Na2CO 3-MgCO3±H2O at 6 GPa and the stability of Na2Mg(CO3)2 in the upper mantle",

abstract = "Phase relations in the Na2CO3-MgCO3 system have been studied in high-pressure high-temperature (HPHT) multi-anvil experiments using graphite capsules at 6.0 ± 0.5 GPa pressures and 900-1400 °C temperatures. Sub-solidus assemblages are represented by Na 2CO3+Na2Mg(CO3)2 and Na2CO3+Na2Mg(CO3) 2+MgCO3 with the transition boundary near 50 mol% MgCO3 in the system. The Na2CO3-Na 2CO3+Na2Mg(CO3)2 eutectic is established at 1200 °C and 29 mol% MgCO3. Melting of Na 2CO3 occurs between 1350 and 1400 °C. We propose that Na2CO3+Na2Mg(CO3)2 disappears between 1200 and 1250 °C via congruent melting. Magnesite remains as a liquidus phase above 1300 °C. Measurable amounts of Mg in Na 2CO3 suggest an existence of MgCO3 solid-solutions in Na2CO3 at given experimental conditions. The maximum MgCO3 solubility in Na-carbonate of about 9 mol% was established at 1100 and 1200 °C. The Na2CO3 and Na2CO3+Na2Mg(CO3)2 compounds have been studied using in situ X-ray coupled with a DIA-type multi-anvil apparatus. The studies showed that eitelite is a stable polymorph of Na2CO3+Na2Mg(CO3)2 at least up to 6.6 GPa and 1000 °C. In contrast, natrite, γ-Na 2CO3, is not stable at high pressure and is replaced by β-Na2CO3. The latter was found to be stable at pressures up to 11.7 GPa at 27 °C and up to 15.2 GPa at 1200 °C and temperatures at least up to 800 °C at 2.5 GPa and up to 1000 °C at 6.4 GPa. The X-ray and Raman study of recovered samples showed that, under ambient conditions, β-Na2CO3 transforms back to γ-Na2CO3. Eitelite [Na2CO 3+Na2Mg(CO3)2] would be an important mineral controlling insipient melting in subducting slab and upwelling mantle. At 6 GPa, melting of the Na2CO3+Na2Mg(CO 3)2+MgCO3 assemblage can be initiated, either by heating to 1300 °C under {"}dry{"} conditions or at 900-1100 °C under hydrous conditions. Thus, the Na2CO3+Na 2Mg(CO3)2 could control the solidus temperature of the carbonated mantle under {"}dry{"} conditions and cause formation of the Na- and Mg-rich carbonatite melts similar to those found as inclusions in olivines from kimberlites and the deepest known mantle rock samples-sheared peridotite xenoliths (190-230 km depth).",

keywords = "Alkaline carbonates, Earth's mantle, Eitelite, High-pressure experiment, In situ X-ray diffraction, Natrite, Raman",

author = "Anton Shatskiy and Gavryushkin, {Pavel N.} and Sharygin, {Igor S.} and Litasov, {Konstantin D.} and Kupriyanov, {Igor N.} and Yuji Higo and Borzdov, {Yuri M.} and Funakoshi, {Ken Ichi} and Palyanov, {Yuri N.} and Eiji Ohtani",

note = "Funding Information: We thank R.W. Luth and K. Kiseeva for thorough reviews and suggestions and J. Kung and K. Putirka for editorial handling and comments. The synchrotron radiation experiments were performed at the BL04B1 in SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (proposals 2010B1308, 2011B1416, 2011B1163, and 2012B1548). This study was conducted as a part of the Global Center-of-Excellence program at Tohoku University. This work was also supported by the Ministry of Education and Science of Russia (project nos. 14.B37.21.0601 and 14.B25.31.0032) and by the Russian Foundation for Basic Research (project nos. 12-05-01167 and 12-05-33008).",

year = "2013",

doi = "10.2138/am.2013.4418",

language = "English",

volume = "98",

pages = "2172--2182",

journal = "American Mineralogist",

issn = "0003-004X",

publisher = "Mineralogical Society of America",

number = "11-12",

}

TY - JOUR

T1 - Melting and subsolidus phase relations in the system Na2CO 3-MgCO3±H2O at 6 GPa and the stability of Na2Mg(CO3)2 in the upper mantle

AU - Shatskiy, Anton

AU - Gavryushkin, Pavel N.

AU - Sharygin, Igor S.

AU - Litasov, Konstantin D.

AU - Kupriyanov, Igor N.

AU - Higo, Yuji

AU - Borzdov, Yuri M.

AU - Funakoshi, Ken Ichi

AU - Palyanov, Yuri N.

AU - Ohtani, Eiji

N1 - Funding Information: We thank R.W. Luth and K. Kiseeva for thorough reviews and suggestions and J. Kung and K. Putirka for editorial handling and comments. The synchrotron radiation experiments were performed at the BL04B1 in SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (proposals 2010B1308, 2011B1416, 2011B1163, and 2012B1548). This study was conducted as a part of the Global Center-of-Excellence program at Tohoku University. This work was also supported by the Ministry of Education and Science of Russia (project nos. 14.B37.21.0601 and 14.B25.31.0032) and by the Russian Foundation for Basic Research (project nos. 12-05-01167 and 12-05-33008).

PY - 2013

Y1 - 2013

N2 - Phase relations in the Na2CO3-MgCO3 system have been studied in high-pressure high-temperature (HPHT) multi-anvil experiments using graphite capsules at 6.0 ± 0.5 GPa pressures and 900-1400 °C temperatures. Sub-solidus assemblages are represented by Na 2CO3+Na2Mg(CO3)2 and Na2CO3+Na2Mg(CO3) 2+MgCO3 with the transition boundary near 50 mol% MgCO3 in the system. The Na2CO3-Na 2CO3+Na2Mg(CO3)2 eutectic is established at 1200 °C and 29 mol% MgCO3. Melting of Na 2CO3 occurs between 1350 and 1400 °C. We propose that Na2CO3+Na2Mg(CO3)2 disappears between 1200 and 1250 °C via congruent melting. Magnesite remains as a liquidus phase above 1300 °C. Measurable amounts of Mg in Na 2CO3 suggest an existence of MgCO3 solid-solutions in Na2CO3 at given experimental conditions. The maximum MgCO3 solubility in Na-carbonate of about 9 mol% was established at 1100 and 1200 °C. The Na2CO3 and Na2CO3+Na2Mg(CO3)2 compounds have been studied using in situ X-ray coupled with a DIA-type multi-anvil apparatus. The studies showed that eitelite is a stable polymorph of Na2CO3+Na2Mg(CO3)2 at least up to 6.6 GPa and 1000 °C. In contrast, natrite, γ-Na 2CO3, is not stable at high pressure and is replaced by β-Na2CO3. The latter was found to be stable at pressures up to 11.7 GPa at 27 °C and up to 15.2 GPa at 1200 °C and temperatures at least up to 800 °C at 2.5 GPa and up to 1000 °C at 6.4 GPa. The X-ray and Raman study of recovered samples showed that, under ambient conditions, β-Na2CO3 transforms back to γ-Na2CO3. Eitelite [Na2CO 3+Na2Mg(CO3)2] would be an important mineral controlling insipient melting in subducting slab and upwelling mantle. At 6 GPa, melting of the Na2CO3+Na2Mg(CO 3)2+MgCO3 assemblage can be initiated, either by heating to 1300 °C under "dry" conditions or at 900-1100 °C under hydrous conditions. Thus, the Na2CO3+Na 2Mg(CO3)2 could control the solidus temperature of the carbonated mantle under "dry" conditions and cause formation of the Na- and Mg-rich carbonatite melts similar to those found as inclusions in olivines from kimberlites and the deepest known mantle rock samples-sheared peridotite xenoliths (190-230 km depth).

AB - Phase relations in the Na2CO3-MgCO3 system have been studied in high-pressure high-temperature (HPHT) multi-anvil experiments using graphite capsules at 6.0 ± 0.5 GPa pressures and 900-1400 °C temperatures. Sub-solidus assemblages are represented by Na 2CO3+Na2Mg(CO3)2 and Na2CO3+Na2Mg(CO3) 2+MgCO3 with the transition boundary near 50 mol% MgCO3 in the system. The Na2CO3-Na 2CO3+Na2Mg(CO3)2 eutectic is established at 1200 °C and 29 mol% MgCO3. Melting of Na 2CO3 occurs between 1350 and 1400 °C. We propose that Na2CO3+Na2Mg(CO3)2 disappears between 1200 and 1250 °C via congruent melting. Magnesite remains as a liquidus phase above 1300 °C. Measurable amounts of Mg in Na 2CO3 suggest an existence of MgCO3 solid-solutions in Na2CO3 at given experimental conditions. The maximum MgCO3 solubility in Na-carbonate of about 9 mol% was established at 1100 and 1200 °C. The Na2CO3 and Na2CO3+Na2Mg(CO3)2 compounds have been studied using in situ X-ray coupled with a DIA-type multi-anvil apparatus. The studies showed that eitelite is a stable polymorph of Na2CO3+Na2Mg(CO3)2 at least up to 6.6 GPa and 1000 °C. In contrast, natrite, γ-Na 2CO3, is not stable at high pressure and is replaced by β-Na2CO3. The latter was found to be stable at pressures up to 11.7 GPa at 27 °C and up to 15.2 GPa at 1200 °C and temperatures at least up to 800 °C at 2.5 GPa and up to 1000 °C at 6.4 GPa. The X-ray and Raman study of recovered samples showed that, under ambient conditions, β-Na2CO3 transforms back to γ-Na2CO3. Eitelite [Na2CO 3+Na2Mg(CO3)2] would be an important mineral controlling insipient melting in subducting slab and upwelling mantle. At 6 GPa, melting of the Na2CO3+Na2Mg(CO 3)2+MgCO3 assemblage can be initiated, either by heating to 1300 °C under "dry" conditions or at 900-1100 °C under hydrous conditions. Thus, the Na2CO3+Na 2Mg(CO3)2 could control the solidus temperature of the carbonated mantle under "dry" conditions and cause formation of the Na- and Mg-rich carbonatite melts similar to those found as inclusions in olivines from kimberlites and the deepest known mantle rock samples-sheared peridotite xenoliths (190-230 km depth).

KW - Alkaline carbonates

KW - Earth's mantle

KW - Eitelite

KW - High-pressure experiment

KW - In situ X-ray diffraction

KW - Natrite

KW - Raman

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