In situ X-ray diffraction of silicate liquids and glasses under dynamic and static compression to megabar pressures

Significance Understanding the structural changes silicate melts undergo over the pressure–temperature range of the Earth’s mantle has been a major, longstanding challenge in the geosciences. Experimental studies are extremely difficult due to required temperatures exceeding 4,000 K needed to melt silicates over megabar pressures. To overcome this issue, laser-driven shock experiments combined with X-ray free-electron lasers were performed to provide nanosecond resolution on silicate structural transformations. By comparison with statically compressed diamond-anvil cell experiments at ambient temperature, a common high-pressure structural evolution of glasses and liquid silicates was revealed. This supports the concept that silicate glasses of dominant mantle composition are suitable structural analogues for the corresponding liquids at these pressures. Properties of liquid silicates under high-pressure and high-temperature conditions are critical for modeling the dynamics and solidification mechanisms of the magma ocean in the early Earth, as well as for constraining entrainment of melts in the mantle and in the present-day core–mantle boundary. Here we present in situ structural measurements by X-ray diffraction of selected amorphous silicates compressed statically in diamond anvil cells (up to 157 GPa at room temperature) or dynamically by laser-generated shock compression (up to 130 GPa and 6,000 K along the MgSiO3 glass Hugoniot). The X-ray diffraction patterns of silicate glasses and liquids reveal similar characteristics over a wide pressure and temperature range. Beyond the increase in Si coordination observed at 20 GPa, we find no evidence for major structural changes occurring in the silicate melts studied up to pressures and temperatures exceeding Earth’s core mantle boundary conditions. This result is supported by molecular dynamics calculations. Our findings reinforce the widely used assumption that the silicate glasses studies are appropriate structural analogs for understanding the atomic arrangement of silicate liquids at these high pressures.

[1]  R. Trønnes,et al.  Core formation, mantle differentiation and core-mantle interaction within Earth and the terrestrial planets , 2019, Tectonophysics.

[2]  G. Morard,et al.  Solving Controversies on the Iron Phase Diagram Under High Pressure , 2018, Geophysical Research Letters.

[3]  P. Caron,et al.  The Rings of Jupiter as Seen by the Electron and Proton Radiation Belt Model Salammbô , 2018, Geophysical Research Letters.

[4]  Marius Millot,et al.  Thermodynamic properties of MgSiO3 at super-Earth mantle conditions , 2018, Physical Review B.

[5]  G. Shen,et al.  Pressure-induced structural change in MgSiO3 glass at pressures near the Earth’s core–mantle boundary , 2018, Proceedings of the National Academy of Sciences.

[6]  M. Burghammer,et al.  SiO_{2} Glass Density to Lower-Mantle Pressures. , 2017, Physical review letters.

[7]  B. Nagler,et al.  Time-resolved diffraction of shock-released SiO2 and diaplectic glass formation , 2017, Nature Communications.

[8]  L. Skinner,et al.  Beyond sixfold coordinated Si in SiO2 glass at ultrahigh pressures , 2017, Proceedings of the National Academy of Sciences.

[9]  C. Sanloup.  Density of magmas at depth , 2016 .

[10]  E. Garnero,et al.  Continent-sized anomalous zones with low seismic velocity at the base of Earth's mantle , 2016 .

[11]  A. Zeidler,et al.  Pressure-driven transformation of the ordering in amorphous network-forming materials , 2016 .

[12]  A. Ravasio,et al.  Decaying shock studies of phase transitions in MgO‐SiO2 systems: Implications for the super‐Earths' interiors , 2016, 1604.01554.

[13]  M. Burghammer,et al.  Fate of MgSiO3 melts at core–mantle boundary conditions , 2015, Proceedings of the National Academy of Sciences.

[14]  H. J. Lee,et al.  Ultrafast visualization of crystallization and grain growth in shock-compressed SiO2 , 2015, Nature Communications.

[15]  G. Rossman,et al.  Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite , 2014, Science.

[16]  L. Stixrude,et al.  First-principles molecular dynamics simulations of MgSiO3 glass: Structure, density, and elasticity at high pressure , 2014 .

[17]  T. Becker,et al.  Dehydration melting at the top of the lower mantle , 2014, Science.

[18]  L. Stixrude.  Melting in super-earths , 2014, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[19]  M. Mezouar,et al.  Equation of state of rhenium and application for ultra high pressure calibration , 2014 .

[20]  G. Cuello,et al.  Structural investigation of glasses along the MgSiO3–CaSiO3 join: Diffraction studies , 2013 .

[21]  G. Morard,et al.  Density measurements and structural properties of liquid and amorphous metals under high pressure , 2013 .

[22]  G. Malenkov.  Argon and water , 2013, Journal of Structural Chemistry.

[23]  Laurent Capolungo,et al.  Virtual diffraction analysis of Ni [0 1 0] symmetric tilt grain boundaries , 2013 .

[24]  M. Mezouar,et al.  Use of a multichannel collimator for structural investigation of low-Z dense liquids in a diamond anvil cell: validation on fluid H2 up to 5 GPa. , 2013, The Review of scientific instruments.

[25]  M. Mezouar,et al.  High-pressure–high-temperature equation of state of KCl and KBr , 2012 .

[26]  B. Militzer.  Ab Initio Investigation of a Possible Liquid-Liquid Phase Transition in MgSiO3 at Megabar Pressures , 2012, 1206.0365.

[27]  L. Elkins‐Tanton.  Magma oceans in the inner solar system , 2012 .

[28]  Gilbert W. Collins,et al.  Evidence for a phase transition in silicate melt at extreme pressure and temperature conditions. , 2012, Physical review letters.

[29]  J. Bass,et al.  Evidence of denser MgSiO3 glass above 133 gigapascal (GPa) and implications for remnants of ultradense silicate melt from a deep magma ocean , 2011, Proceedings of the National Academy of Sciences.

[30]  C. Benmore,et al.  High pressure x-ray diffraction measurements on Mg2SiO4 glass , 2011 .

[31]  G. Morard,et al.  High efficiency multichannel collimator for structural studies of liquids and low-Z materials at high pressures and temperatures. , 2011, The Review of scientific instruments.

[32]  B. Tauzin,et al.  Seismic evidence for a global low-velocity layer within the Earth/'s upper mantle , 2010 .

[33]  Geoffrey E. Hinton,et al.  Melting of Peridotite to 140 Gigapascals , 2010, Science.

[34]  J. Bass,et al.  Elasticity and pressure-induced structural changes in vitreous MgSiO3-enstatite to lower mantle pressures , 2010 .

[35]  L. Stixrude,et al.  Self-consistent thermodynamic description of silicate liquids, with application to shock melting of MgO periclase and MgSiO3 perovskite , 2009 .

[36]  S. Shim,et al.  Compositional dependence of structural transition pressures in amorphous phases with mantle-related compositions , 2009 .

[37]  N. Takegawa,et al.  Rapid aerosol particle growth and increase of cloud condensation nucleus activity by secondary aerosol formation and condensation: A case study for regional air pollution in northeastern China , 2009 .

[38]  T. Ahrens,et al.  The MgSiO3 system at high pressure: Thermodynamic properties of perovskite, postperovskite, and melt from global inversion of shock and static compression data , 2009 .

[39]  Tomoko Sato,et al.  Sixfold-coordinated amorphous polymorph of SiO2 under high pressure. , 2008, Physical review letters.

[40]  N. Coltice,et al.  A crystallizing dense magma ocean at the base of the Earth’s mantle , 2007, Nature.

[41]  L. Stixrude,et al.  Structure and freezing of MgSiO$_3$ liquid in Earth's interior , 2006 .

[42]  L. Stixrude,et al.  Structure and Freezing of MgSiO3 Liquid in Earth's Lower Mantle , 2005, Science.

[43]  M. Mezouar,et al.  Development of a new state-of-the-art beamline optimized for monochromatic single-crystal and powder X-ray diffraction under extreme conditions at the ESRF. , 2005, Journal of synchrotron radiation.

[44]  C. Benmore,et al.  Evidence of different structures in magnesium silicate liquids : coordination changes in forsterite- to enstatite- composition glasses. , 2004 .

[45]  N. Mahowald,et al.  Estimates of atmospheric-processed soluble iron from observations and a global mineral aerosol model: Biogeochemical implications , 2004 .

[46]  C. Benmore,et al.  Coordination changes in magnesium silicate glasses , 2004 .

[47]  T. Ahrens,et al.  Shock‐induced melting of MgSiO3 perovskite and implications for melts in Earth's lowermost mantle , 2004 .

[48]  S. Rodionov.  A sequential algorithm for testing climate regime shifts , 2004 .

[49]  T. Ahrens,et al.  Shock‐compressed MgSiO3 glass, enstatite, olivine, and quartz: Optical emission, temperatures, and melting , 2004 .

[50]  M. Mezouar,et al.  Quantitative structure factor and density measurements of high-pressure fluids in diamond anvil cells by x-ray diffraction: Argon and water , 2002 .

[51]  G. D. Price,et al.  Comparative study of quasiharmonic lattice dynamics, molecular dynamics and Debye model applied to MgSiO3 perovskite. , 2000 .

[52]  Thorne Lay,et al.  The core–mantle boundary layer and deep Earth dynamics , 1998, Nature.

[53]  Wen,et al.  Ultra-Low velocity zones near the core-mantle boundary from broadband PKP precursors , 1998, Science.

[54]  G. Shen,et al.  Measurement of melting temperatures of some minerals under lower mantle pressures , 1995 .

[55]  Steve Plimpton,et al.  Fast parallel algorithms for short-range molecular dynamics , 1993 .

[56]  Mao,et al.  High-pressure x-ray diffraction of SiO2 glass. , 1992, Physical review letters.

[57]  R. Hemley,et al.  Raman and infrared study of pressure-induced structural changes in MgSiO3, CaMgSi2O6, and CaSiO3 glasses , 1992 .