Abstract
Synchrotron-based high-pressure single-crystal X‑ray diffraction experiments were conducted on synthetic clinopyroxenes at room temperature to a maximum pressure of 40 GPa. We studied two crystals with different compositions. A Na-Ti-pyroxene with formula (Na0.86Mg0.14)(Mg0.57Ti0.43)Si2O6 synthesized at P = 7 GPa and T = 1700 °C, and a Na-pyroxene with composition (Na0.886Mg0.085Fe0.029) (Si0.442Mg0.390Fe0.168)Si2O6 synthesized at P = 15 GPa and T = 1500 °C. These phases were found to be monoclinic with the space group C2/c and exhibit KTo of 106.8(2), 121.8(4) GPa, respectively. Na-Tipyroxene is more compressible than Fe-bearing Na-Mg-Si-pyroxene, likely due to the fact that the FeO6 octahedron is significantly more rigid than MgO6 at high pressure. The formation of Na-rich pyroxenes in the deep mantle is related to crystallization of low-degree alkaline carbonate-silicate melts formed when the crust and mantle interact during the slab descent and its stagnation in the transition zone.
Acknowledgments
Constructive reviews of three anonymous referees were very helpful for improving the quality of the manuscript.
Funding
We acknowledge the ESRF and DESY for the provision of synchrotron radiation facilities. This study was supported by the Russian Science Foundation (project no. 17-17-01169 to A.B., E.M., and L.I.). The structural refinement of Na-Ti pyroxene was supported by the Foundation of the President of the Russian Federation (grant no. MK-1277.2017.5 to E.M.). The comparison of the structures of synthesized pyroxenes with the phases available from literature—by the Russian Foundation of Basic Research (grant no. 18-05-00332 to D.P.).
References cited
Angel, R.J. (2000) Equations of state. Reviews in Mineralogy and Geochemistry, 41, 35–59.10.1515/9781501508707-006Search in Google Scholar
Angel, R.J. (2011) Win_Strain program for Strain calculations. http://www.rossangel.com/text_strain.htmSearch in Google Scholar
Angel, R.J., Gasparik, T., Ross, N.L., Finger, L.W., Prewitt, C.T., and Hazen, R.M. (1988) A silica-rich sodium pyroxene phase with six-coordinated silicon. Nature, 335, 156–158.10.1038/335156a0Search in Google Scholar
Angel, R.J., Mazzucchelli, M.L., Alvaro, M., Nimis, P., and Nestola, F. (2014) Geobarometry from host-inclusion systems: the role of elastic relaxation. American Mineralogist, 99, 2146–2149.10.2138/am-2014-5047Search in Google Scholar
Arlt, T., and Angel, R.J. (2000) Displacive phase transitions in C-centred clinopyroxenes: spodumene, LiScSi2O6 and ZnSiO3 Physics and Chemistry of Minerals, 27(10), 719–731.10.1007/s002690000116Search in Google Scholar
Aulbach, S., Griffin, W.L., Pearson, N.J., O’Reilly, S.Y., Kivi, K., and Doyle, B.J. (2004) Mantle formation and evolution, Slave Craton: constraints from HSE abundances and Re–Os isotope systematics of sulfide inclusions in mantle xenocrysts. Chemical Geology, 208(1-4), 61–88.10.1016/j.chemgeo.2004.04.006Search in Google Scholar
Bindi, L., Dymshits, A.M., Bobrov, A.V., Litasov, K.D., Shatskiy, A.F., Ohtani, E., and Litvin, Yu.A. (2011) Crystal chemistry of sodium in the Earth’s interior: The structure of Na2MgSi5O12 synthesized at 17.5 GPa and 1700 °C. American Mineralogist, 96, 447–450.10.2138/am.2011.3716Search in Google Scholar
Bindi, L., Sirotkina, E.A., Bobrov, A.V., Walter, M.J., Pushcharovsky, D.Yu., and Irifune, T. (2017) Bridgmanite-like crystal structure in the novel Ti-rich phase synthesized at transition zone condition. American Mineralogist, 102, 227–230.10.2138/am-2017-5937Search in Google Scholar
Bishop, F.C., Smith, J.V., and Dawson, J.B. (1978) Na, K, P and Ti in garnet, pyroxene and olivine from peridotite and eclogite xenoliths from African kimberlites. Lithos, 11, 155–173.10.1016/0024-4937(78)90006-3Search in Google Scholar
Bobrov, A.V., and Litvin, Yu.A. (2009) Peridotite–eclogite–carbonatite systems at 7.0–8.5 GPa: concentration barrier of diamond nucleation and syngenesis of its silicate and carbonate inclusions. Russian Geology and Geophysics, 50, 1221–1233.10.1016/j.rgg.2009.11.020Search in Google Scholar
Bobrov, A.V., Litvin, Yu.A., Bindi, L., and Dymshits, A.M. (2008) Phase relations and formation of sodium-rich majoritic garnet in the system Mg3Al2Si3O12– Na2MgSi5O12 at 7.0 and 8.5 GPa. Contributions to Mineralogy and Petrology, 156, 243–257.10.1007/s00410-008-0283-3Search in Google Scholar
Bridgman, P.W. (1923) The compressibility of thirty metals as a function of pressure and temperature. Proceedings of the American Academy of Arts and Sciences, 58, 165–242.10.4159/harvard.9780674287815.c14Search in Google Scholar
Cameron, M., and Papike, J.J. (1981) Structural and chemical variations in pyroxenes. American Mineralogist, 66, 1–50.Search in Google Scholar
Cameron, M., Sueno, S., Prewitt, C.T., and Papike, J.J. (1973) High temperature crystal chemistry of acmite, diopside, hedenbergite, jadeite, spodumene, and ureyite. American Mineralogist, 58, 594–618.Search in Google Scholar
Clark, J.R., Appleman, D.E., and Papike, J.J. (1969) Crystal-chemical characterization of clinopyroxenes based on eight new structure refinements. MSA Special Paper, 2, 31–50.Search in Google Scholar
Downs, R.T. (2003) Topology of the pyroxenes as a function of temperature, pressure and composition determined from the procrystal electron density. American Mineralogist, 88, 556–566.10.2138/am-2003-0409Search in Google Scholar
Dymshits, A.M., Bobrov, A.V., Litasov, K.D., Shatskiy, A.F., Ohtani, E., and Litvin, Yu.A. (2010) Experimental study of the pyroxene-garnet phase transition in the Na2MgSi5O12 system at pressures of 13–20 GPa: First synthesis of sodium majorite. Doklady Earth Sciences, 434, 1263–1266.10.1134/S1028334X10090266Search in Google Scholar
Dymshits, A.M., Bobrov, A.V., Bindi, L., Litvin, Y.A., Litasov, K.D., Shatskiy, A.F., and Ohtani, E. (2013) Na-bearing majoritic garnet in the Na2MgSi5O12– Mg3Al2Si3O12 join at 11–20 GPa: Phase relations, structural peculiarities and solid solutions. Geochimica et Cosmochimica Acta, 105, 1–13.10.1016/j.gca.2012.11.032Search in Google Scholar
Dymshits, A., Sharygin, I., Litasov, K., Shatskiy, A., Gavryushkin, P., Ohtani, E., Suzuki, A., and Funakoshi, K. (2015) In situ observation of the pyroxenemajorite transition in Na2MgSi5O12 using synchrotron radiation and Raman spectroscopy of Na-majorite. American Mineralogist, 100, 378–384.10.2138/am-2015-4801Search in Google Scholar
Fei, Y., Ricolleau, A., Frank, M., Mibe, K., Shen, G., and Prakapenka, V. (2007) Toward an internally consistent pressure scale. Proceedings of the National Academy of Sciences, 104, 9182–9186.10.1073/pnas.0609013104Search in Google Scholar PubMed PubMed Central
Finger, L.W., and Hazen, R.M. (2000) Systematics of high-pressure silicate structures. Reviews in Mineralogy and Geochemistry, 41, 123–155.10.1515/9781501508707-009Search in Google Scholar
Frost, D.J., Poe, B.T., Trønnes, R.G., Liebske, C., Duba, A., and Rubie, D.C. (2004) A new large-volume multianvil system. Physics of the Earth and Planetary Interiors, 143-144, 507–514.10.1016/j.pepi.2004.03.003Search in Google Scholar
Gasparik, T. (1988) The synthesis of a new pyroxene-NaMg0.5Si2.5O6 and garnet near the diopside–jadeite join. Eos Transactions, 69, 500.Search in Google Scholar
Gasparik, T. (1989) Transformation of enstatite–diopside–jadeite pyroxenes to garnet. Contributions to Mineralogy and Petrology, 102(4), 389–405.10.1007/BF00371083Search in Google Scholar
Gatta, G.D., Boffa Ballaran, T., and Iezzi, G. (2005) High-pressure X‑ray and Raman study of a ferrian magnesian spodumene. Physics and Chemistry of Minerals, 32(2), 132–139.10.1007/s00269-005-0450-2Search in Google Scholar
Hazen, R.M. (1993) Comparative compressibilities of silicate spinels: Anomalous behavior of (Mg,Fe)2SiO4 Science, 259, 206–209.10.1126/science.259.5092.206Search in Google Scholar
Hazen, R.M., and Finger, L.W. (1977) Crystal structure and compositional variation of Angra dos Reis fassaite. Earth and Planetary Science Letters, 35(2), 357–362.10.1016/0012-821X(77)90138-8Search in Google Scholar
Levien, L., and Prewitt, C.T. (1981) High-pressure structural study of diopside. American Mineralogist, 66, 315–323.Search in Google Scholar
McCarthy, A.C., Downs, R.T., and Thompson, R.M. (2008) Compressibility trends of the clinopyroxenes, and in situ high-pressure single-crystal X‑ray diffraction study of jadeite. American Mineralogist, 93, 198–209.10.2138/am.2008.2521Search in Google Scholar
Momma, K., and Izumi, F. (2011) VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data. Journal of Applied Crystallography, 44(6), 1272–1276.10.1107/S0021889811038970Search in Google Scholar
Nestola, F., Boffa Ballaran, T., Liebske, C., Bruno, M., and Tribaudino, M. (2006) High-pressure behaviour along the jadeite NaAlSi2O6–aegirine NaFeSi2O6 solid solution up to 10 GPa. Physics and Chemistry of Minerals, 33(6), 417–425.10.1007/s00269-006-0089-7Search in Google Scholar
Ninomiya, E., Isobe, M., Ueda, Y., Nishi, M., Ohoyama, K., Sawa, H., and Ohama, T. (2003) Observation of lattice dimerization in spin singlet low temperature-phase of NaTiSi2O6 Physica B, 329, 884–885.10.1016/S0921-4526(02)02559-0Search in Google Scholar
Ohashi, H. (2003) Crystal Structures of (Na,Ca)(Ti,Mg)Si2O6 clinopyroxenes: X-ray study on Si-O bonding. Maruzen Publishing Service Center, Tokyo.Search in Google Scholar
Ohashi, H., Fujita, T., and Osawa, T. (1982) The crystal structure of NaTiSi2O6 pyroxene. The Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists, 77, 305–309.10.2465/ganko1941.77.305Search in Google Scholar
Petricek, V., Dusek, M., and Palatinus, L. (2014) Crystallographic Computing System JANA2006: General features. Zeitschrift für Kristallographie-Crystalline Materials, 229, 345.10.1515/zkri-2014-1737Search in Google Scholar
Prewitt, C.T., and Burnham, C.W. (1966) The crystal structure of jadeite, NaAlSi2O6 American Mineralogist, 51, 956–975.Search in Google Scholar
Prewitt, C.T., Shannon, R.D., and White, W.B. (1972) Synthesis of a pyroxene containing trivalent titanium. Contributions to Mineralogy and Petrology, 35, 77–82.10.1007/BF00397379Search in Google Scholar
Pushcharovsky, D.Y. (2004) Mineral transformation processes in deep geospheres. Moscow University Geology Bulletin, 59(2), 1–11.Search in Google Scholar
Redhammer, G.J., Ohashi, H., and Roth, G. (2003) Single-crystal structure refinement of NaTiSi2O6 clinopyroxene at low temperatures (298 < T < 100 K). Acta Crystallographica, B59(6), 730–746.10.1107/S0108768103022018Search in Google Scholar PubMed
Robinson, K., Gibbs, G.V., and Ribbe, P.H. (1971) Quadratic elongation: a quantitative measure of distortion in coordination polyhedra. Science, 172, 567–570.10.1126/science.172.3983.567Search in Google Scholar PubMed
Rudnick, R.L., Gao, S., Ling, W.L., Liu, Y.S., and McDonough, W.F. (2004) Petrology and geochemistry of spinel peridotite xenoliths from Hannuoba and Qixia, North China craton. Lithos, 77(1), 609–637.10.1016/j.lithos.2004.03.033Search in Google Scholar
Sirotkina, E.A., Bobrov, A.V., Spivak, A.V., Bindi, L., and Pushcharovsky, D.Y. (2016) X‑ray single-crystal and Raman study of (Na0.86Mg0.14(Mg0.57Ti0.43 Si2O6 a new pyroxene synthesized at 7 GPa and 1700 °C. Physics and Chemistry of Minerals, 43(7), 731–738.10.1007/s00269-016-0829-2Search in Google Scholar
Sours-Page, R., Johnson, K.T., Nielsen, R.L., and Karsten, J.L. (1999) Local and regional variation of MORB parent magmas: evidence from melt inclusions from the Endeavour Segment of the Juan de Fuca Ridge. Contributions to Mineralogy and Petrology, 134(4), 342–363.10.1007/s004100050489Search in Google Scholar
Stixrude, L., and Lithgow-Bertelloni, C. (2005) Mineralogy and elasticity of the oceanic upper mantle: origin of the low-velocity zone. Journal of Geophysical Research: Solid Earth, 110, B03204.10.1029/2004JB002965Search in Google Scholar
Thompson, R.M., and Downs, R.T. (2004) Model pyroxenes II: Structural variation as a function of tetrahedral rotation. American Mineralogist, 89, 614–628.10.2138/am-2004-0416Search in Google Scholar
Thompson, R.M., and Downs, R.T. (2008) The crystal structure of diopside at pressure to 10 GPa. American Mineralogist, 93, 177–186.10.2138/am.2008.2684Search in Google Scholar
Thompson, R.M., Downs, R.T., and Redhammer, G.J. (2005) Model pyroxenes III: Volume of C2/c pyroxenes at mantle PT and x American Mineralogist, 90, 1840–1851.10.2138/am.2005.1854Search in Google Scholar
Thomson, A.R., Walter, M. J., Kohn, S.C., and Brooker, R.A. (2016) Slab melting as a barrier to deep carbon subduction. Nature, 529, 76–79.10.1038/nature16174Search in Google Scholar PubMed
Tribaudino, M., Prencipe, M., Nestola, F., and Hanfland, M. (2001) AP21/c-C2/c high-pressure phase transition in Ca0.5Mg1.5Si2O6 clinopyroxene. American Mineralogist, 86, 807–813.10.2138/am-2001-0704Search in Google Scholar
Ullrich, A., Miletich, R., Balič-Žunić, T., Olsen, L., Nestola, F., Wildner, M., and Ohashi, H. (2010) (Na,Ca)(Ti3+Mg)Si2O6-clinopyroxenes at high pressure: Influence of cation substitution on elastic behavior and phase transition. Physics and Chemistry of Minerals, 37, 25–43.10.1007/s00269-009-0307-1Search in Google Scholar
Walter, M.J., Bulanova, G.P., Armstrong, L.S., Keshav, S., Blundy, J.D., Gudfinnsson, G., and Gobbo, L. (2008) Primary carbonatite melt from deeply subducted oceanic crust. Nature, 454, 622–625.10.1038/nature07132Search in Google Scholar PubMed
Wang, W., and Gasparik, T. (2000) Evidence for a deep-mantle origin of a NaPx-En inclusion in diamond. International Geology Review, 42(11), 1000–1006.10.1080/00206810009465122Search in Google Scholar
Wang, W., and Sueno, S. (1996) Discovery of a NaPx-En inclusion in diamond: Possible transition zone origin. Mineralogical Journal, 18(1), 9–16.10.2465/minerj.18.9Search in Google Scholar
Xu, J., Zhang, D., Fan, D., Downs, R.T., Hu, Y., and Dera, P.K. (2017) Isosymmetric pressure-induced bonding increase changes compression behavior of clinopyroxenes across jadeite-aegirine solid solution in subduction zones. Journal of Geophysical Research: Solid Earth, 122(1), 142–157.10.1002/2016JB013502Search in Google Scholar
Yang, H., and Konzett, J. (2005) Crystal chemistry of a high-pressure C2/c clinopyroxene with six-coordinated silicon. American Mineralogist, 90, 1223–1226.10.2138/am.2005.1906Search in Google Scholar
Yang, H., and Prewitt, C.T. (2000) Chain and layer silicates at high temperatures and pressures. Reviews in Mineralogy and Geochemistry, 41, 211–255.10.1515/9781501508707-012Search in Google Scholar
Yang, H., Konzett, J., Frost, D.J., and Downs, R.T. (2009) X‑ray diffraction and Raman spectroscopic study of clinopyroxenes with six-coordinated Si in the Na (Mg0.5Si0.5Si2O6-NaAlSi2O6 system. American Mineralogist, 94, 942–949.10.2138/am.2009.3084Search in Google Scholar
Zhang, L., Ahsbahs, H., Hafner, S.S., and Kutoglu, A. (1997) Single-crystal compression and crystal structure of clinopyroxene up to 10 GPa. American Mineralogist, 82, 245–258.10.2138/am-1997-3-402Search in Google Scholar
Zhao, Y., Von Dreele, R.B., Shankland, T.J., Weidner, D.J., Zhang, J.Z., Wang, Y.B., and Gasparik, T. (1997) Thermoelastic equation of state of jadeite NaAlSi2O6 an energy-dispersive Reitveld refinement study of low symmetry and multiple phases diffraction. Geophysical Research Letters, 24, 5–8.10.1029/96GL03769Search in Google Scholar
© 2019 Walter de Gruyter GmbH, Berlin/Boston
