SIT06-P01

Room:Convention Hall

Time:May 25 18:15-19:30

Hydrostaticity and Equation of states of NaCl, KCl, KBr up to 70 GPa at room temperature
KAMADA, Seiji1∗ ; MAEDA, Fumiya2 ; TAKAHATA, Akihiro2 ; AMAIKE, Yohei2 ; OHTANI, Eiji2 ;HIRAO, Naohisa3 ; OHISHI, Yasuo3
1

FRIIS, Tohoku Univ., 2 Dept, Earth Sci., Grad. School of Sci. Tohoku Univ., 3 JASRI

Recently, the high pressures and temperatures corresponding to the inner Earth’s core have been achieved due to the progressof the experimental techniques (e.g., Tateno et al., 2010). To understand the physical properties of the Earth’s core, it is essential
to perform high pressure and temperature experiments. Fiquet et al. (2001) reported first results on sound velocities of Fe by aninelastic X-ray measurement over 100 GPa. Antonangeli et al. (2004) and Ohtani et al. (2013) also reported sound velocities of
Fe over 100 GPa. Fiquet et al. (2001) reported slow sound velocities above 100 GPa due to preferred orientation of iron. They
concluded the preferred orientation was caused by a uniaxial compression using a diamond anvil cell and slow sound velocities
propagated along c-axis were observed. Therefore, hydrostatical compression is essential to avoid texturing of the samples andunderstand physical properties under high pressure.
To produce hydrostatic condition under high pressures, some liquid pressure media have been used, such as 4:1 (in volume
ratio) Methanol Ethanol mixture (ME), 16:3:1 (in volume ratio) Methanol Ethanol Water mixture (MEW). Those materials are
solidify at around 10 GPa. Therefore, the hydrostatic conditions are limited up to 10 GPa. Noble gases are also used as pressure
media. He is solidified at 12 GPa and Ne is solidified at 5 GPa. They show hydrostatic behavior up to 40 and 20 GPa, respectively.
Although they are good material to produce hydrostatic compressions, ME and MEW are reactive under high temperature andthe noble gases require a special equipment to load them into a sample chamber. In this study, we employed alkali halides (NaCl,KCl, KBr) as pressure media, which are relatively soft and are expected to produce pseudo hydrostatic condition.
A foil made from powdered Au was used as a pressure scale (Fei et al., 2007) and a laser absorber. The foil was embedded
between alkali halides pellets which served as pressure media and thermal insulators. A symmetric diamond anvil cell was used
to generate high pressure. A double-sided laser heating method using fiber lasers was used for annealing the Au foil under highpressures for 10 min. Experimental pressure was imposed to the sample every a few GPa step and its X-ray diffraction (XRD)
patterns were taken at room temperature. At 50 GPa and 70 GPa, the sample was annealed in order to reduce stress in the chamber. XRD patterns were taken before and after annealing. All XRD patterns were taken at BL10XU of SPring-8, Japan (Ohishi
et al. 2008). The diameter of the X-ray beam was collimated to be 20 µm. The volume of Au at ambient pressure was measured
to be 67.69(5) Å3 (a=4.0755(9) Å) at the BL10XU, SPring-8. The gold volume obtained here was used for V0 in the equation ofstate for Au to calculate experimental pressures.
We have obtained XRD patterns from the samples between 1 and 70 GPa and annealed the samples at 2000 K at 50 and 70 GPa.
KCl, KBr, and NaCl transformed from B1 to B2 phase at 2.6, 2.8, and 32.6 GPa, respectively. The standard deviations of thepressure distributions in the chamber decreased slightly due to the transformations. The pressure standard deviations increased
from 0.1 GPa at 1 GPa to 0.2 GPa at 20 GPa. After further compressions, the pressure distributions of Au in NaCl was almost
constant but those in KCl and KBr increased up to 0.8 GPa and 1.2 GPa, respectively. After annealing at 50 GPa, the pressure
distributions slightly reduced in KCl and KBr but they increased in NaCl. The compression behaviors of KCl and KBr are ingood agreement with Dewaele et al. (2012) and those of NaCl are consistent with Dorfman et al. (2012).

Keywords: equation of state, hydrostatic compression, alkali halides, high pressure

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SIT06-P02

Room:Convention Hall

Time:May 25 18:15-19:30

Jadeite in shocked meteorites: various textures and formation processes
OZAWA, Shin1∗ ; MIYAHARA, Masaaki2 ; OHTANI, Eiji1 ; ITO, Yoshinori1 ; SUZUKI, Akio1 ;KIMURA, Makoto3 ; KOROLEVA, Olga N.4 ; LITASOV, Konstantin5 ; POKHILENKO, Nikolay P.5
1

Department of Earth Science, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan, 2 Department of Earthand Planetary Systems Science, Graduate School of Science, Hiroshima University,, 3 Faculty of Science, Ibaraki University,
Mito 310-8512, Japan, 4 Institute of Mineralogy, UB RAS, Miass, 456317, Russia, 5 V. S. Sobolev Institute of Geology andMineralogy, SB RAS, Novosibirsk, 630090, Russia
Introduction
Collision of materials is one of the most fundamental processes in planet formation of the early solar system. Heavily-shocked
meteorites sometimes contain high-pressure minerals, which provide important constraints on the nature of the impact events.
Jadeite is a high-pressure mineral identified in various types of meteorites such as H, L and LL chondrites, and Martian meteorites[1-8]. Here, we show various occurrences of jadeite observed in shocked meteorites, and discuss the conditions and mechanismsof jadeite formation.
Results and Discussions
Heavily-shocked ordinary chondrites (H, L and LL) were mainly observed in our studies. They consist of chondritic host-rockand pervasive shock-induced melt veins (SMVs). Jadeite is usually identified in fragments of the host-rock entrained to the
SMVs. Albitic feldspar grains in these fragments have been replaced by jadeite plus amorphous material.
A variety of texture was observed in jadeite-bearing grains of Sahara 98222 L6 chondrite, such as “particle-like” , “stringerlike” , and “polycrystalline-like” phases [4]. Similar textures were also reported in jadeite-bearing grains of other L and H
ordinary chondrites [5], and shocked rocks from Ries crater, Germany [7]. Detailed TEM observations by Miyahara et al.
[5] clarified that these jadeite-bearing grains consist of massive or network-like assemblages of jadeite crystals and interstitialamorphous (or poorly-crystallized) materials. Bulk chemical compositions of the jadeite-bearing grains are almost identical tothat of albitic feldspar in the host-rocks. Therefore, the jadeite described above is considered to have formed by solid-state
reactions.
On the other hand, we recently found a new occurrence of jadeite in Chelyabinsk LL5 chondrite [8]. Needle-like or skeletalrhombic crystals of jadeite coexist with amorphous material. The bulk chemical compositions of the jadeite-bearing grains aredifferent (more K-rich) from that of albitic feldspar in the host-rock. In addition, jadeite-rich part is enriched in Na, whereas theamorphous part is highly enriched in K. The significant element migrations appear to be difficult in solid-state reactions during ashort duration of an impact. Thus, jadeite in Chelyabinsk meteorite is considered to have crystallized from feldspathic melt.
It is experimentally revealed that albite dissociate into jadeite plus silica phase over 3 GPa, and jadeite can be stable at 3-19
GPa as a liquidus or subsolidus phase [9-14]. The two types of jadeite formation (from solid or melt) were probably caused bydifferent temperature conditions. For the jadeite formed by solid-state reactions, the temperature is considered to have been lower
than at least 1400 ℃, the melting temperature of albite at 3 GPa [10,11]. For the jadeite formed from melt, the temperature could
have been higher than 1400 ℃. The different textures and chemical compositions of the jadeite-bearing grains reflect different
P-T-t (Pressure-Temperature-time) conditions during the impact events on different parent bodies of the meteorites.
References[1] Kimura et al. (2000) Meteorit. Planet. Sci. 35, A87-A88.
[2] Kimura et al. (2001) Meteorit. Planet. Sci. 36, A99.
[3] Ohtani et al. (2004) Earth Planet. Sci. Lett. 227, 505-515.
[4] Ozawa et al. (2009) Meteorit. Planet. Sci. 44, 1771-1786.
[5] Miyahara et al. (2013) Earth Planet. Sci. Lett. 373, 102-108.
[6] El Goresy et al. (2013) Lunar Planet. Sci. Conf. 44, 1037.
[7] James (1969) Science 165, 1006-1008.
[8] Ozawa et al. (2014) Sci. Rep. 4, 5033.
[9] Birch & LeCompte (1960) Am. J. Sci. 258, 209-217.
[10] Boyd & England (1963) J. Geophys. Res. 68, 311-323.
[11] Bell & Roseboom, Jr (1969) in Pyroxenes and Amphiboles: Crystal Chemistry and Phase Petrology,151-161.
[12] Liu (1978) Earth Planet. Sci. Lett. 37, 438-444.
[13] Yagi et al. (1994) Phys. Chem. Min. 21, 12-17.

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SIT06-P02

Room:Convention Hall

Time:May 25 18:15-19:30[14] Tutti (2007) Phys. Earth Planet. Int. 161, 143-149.
Keywords: jadeite, meteorite, impact, high-pressure mineral, shock melt vein, formation mechanism

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SIT06-P03

Room:Convention Hall

Time:May 25 18:15-19:30

Viscosity and structure of anorthite melt under high pressure and high temperature conditions
SAKAMAKI, Tatsuya1∗ ; KONO, Yoshio2
1

Department of Earth and Planetary Materials Science, Tohoku University, 2 HPCAT, Geophysical Laboratory, Carnegie Institution of Washington
The viscosity and structure of the anorthite (CaAl2 Si2 O8 ) melt has been measured up to 6.1 GPa and 2173 K using the in-situ
falling sphere method with X-ray radiography for viscosity and energy-dispersive X-ray diffraction technique for structure atbeamline 16-BM-B of the Advanced Photon Source. The viscosity of the melt decreases with pressure up to 4 GPa, and then increases. The viscosity and its pressure dependence of anorthite melt are smaller than albite melt, which is also fully polymerized
melt. Obtained structural information support the difference in viscosity behavior between anorthite and albite melts. Anorthitemelt shows a smaller shift of the first sharp diffraction peak (FSDP) in the structure factor, S(Q), to higher-Q with pressure thanalbite one, indicating the pressure-induced structural shrinkage of an intermediate-range order is small. The radial distributionfunction, G(r), of anorthite melts exhibits the longer T-O distance, which is the length between tetrahedrally coordinated cations
and oxygen. The TO4 tetrahedra are the most fundamental units in the silicate melts, and the T-O distance reflects strength of theunits. Thus, anorthite melt initially shows the low viscosity due to longer T-O distance. On the other hand, a pressure dependenceof T-T distance in anorthite melt is smaller than albite one, and T-O-T angle is also small.
Keywords: viscosity, structure, anorthite melt, albite melt, high pressure

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SIT06-P04

Room:Convention Hall

Time:May 25 18:15-19:30

The effect of Ni and C on sound velocity of liquid Fe at high pressure
KUWABARA, Soma1 ; TERASAKI, Hidenori1∗ ; SHIMOYAMA, Yuta1 ; NISHIDA, Keisuke2 ; HIGO, Yuji3 ;TAKUBO, Yusaku1 ; SHIBAZAKI, Yuki4 ; TAHARA, Masaki4 ; IGARASHI, Mako4 ; SAKAMAKI, Tatsuya4 ;TANGE, Yoshinori3 ; KONDO, Tadashi1
1Department of Earth and Space Science, Osaka University, 2 Department of Earth and Planetary Science, The University ofTokyo, 3 Japan Synchrotron Radiation Research Institute, 4 Department of Earth and Planetary Materials Science, Tohoku University
Nickel is a highly plausible element in the terrestrial core together with iron. However, the effect of Ni on elastic properties ofliquid Fe at high pressure has not been reported. It is important to study the effect of Ni together with light elements on the soundvelocity of liquid Fe to give a constraint on the liquid core composition of terrestrial planets by comparing with the observed
seismic data. In this study, we focused on the effect of Ni and C on the P-wave velocity and elastic properties of liquid Fe up to
6.5 GPa.
High pressure experiments were carried out using 1500 ton Kawai-type multi-anvil press at BL04B1 beamline, SPring-8
synchrotron facility. P-wave velocity (VP ) was measured using pulse-echo overlap method. Used sample compositions were
Fe-10wt%Ni and Fe-10wt%-4wt%C. The sample pellet was sandwiched by single crystal sapphire buffer rods for the VP measurement. The experimental pressures and temperatures were determined based on lattice volumes of MgO and BN, which wereused as a pressure marker, combined with their equations of state. The measurements were performed up to 6.5 GPa and 2100 K.
Obtained VP of liquid Fe-Ni is located slightly lower and aligned almost parallel to the VP curve of liquid Fe as a functionof pressure. This suggests that alloying 10 wt% of Ni into liquid Fe slightly decrease the VP but little influence on the bulk
modulus and its pressure dependence. Alloying C slightly increases the VP of liquid Fe and it is also found that the effect oftemperature on the VP is not negligible. In the presentation, we will compare these results with the reported results of other lightelement such as S in the sound velocity-density relation (Birch plot) and discuss a clue to constrain the core composition of smallterrestrial planets.
Keywords: Sound velocity, Fe alloy, Core, High pressure

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SIT06-P05

Room:Convention Hall

Time:May 25 18:15-19:30

Melting relationships in the Fe-S-Si system at high pressure and temperature
SAKAIRI, Takanori1∗ ; OHTANI, Eiji1 ; SAKAI, Takeshi2 ; KAMADA, Seiji1 ; SAKAMAKI, Tatsuya1 ;HIRAO, Naohisa3
1Graduate school of Science, Tohoku Univ., 2 Geodynamics Research Center, Ehime Univ., 3 JASRI

It is widely accepted that the Earth’s core is mainly composed of iron and contains light elements to account for its density
deficit. Alloying with light elements significantly affects the physical properties of iron and depresses its melting temperature.
Therefore, the melting relation of the Fe-light elements system is the key to clarify the thermal structure of the Earth’s core.
Although there are many candidates for light elements in the core, sulfur and silicon are considered to be the major light elements.
Some geochemical models predicted that sulfur and silicon could be present not only in the core of the Earth but also in the coreof other terrestrial planets such as Mars and Mercury. In spite of the importance of the effect of sulfur and silicon on the physicalproperties of iron, there are few previous reports and the melting relationships in the Fe-S-Si system at high pressure were notrevealed in details. To better understand the properties of the planetary cores, we investigated the melting relationships of the
Fe-S-Si system under high-pressure conditions.
Here, we report the phase relationships and melting temperatures in the Fe-S-Si system up to 60 GPa. Melting experiments
were performed in the pressure range of 20-60 GPa and the temperature range of 1300-2500 K using a double-sided laser-heateddiamond anvil cell combined with X-ray diffraction technique. The sample compositions used in this study were Fe80.1 S12.7 Si7.2(Fe-8wt.%S-4wt.%Si) and Fe74.4 S18.5 Si7.1 (Fe-12wt.%S-4wt.%Si). In situ X-ray diffraction experiments were conducted at theBL10XU beamline of the SPring-8 facility. The melting detection was based on disappearance of the X-ray diffraction peaks ofthe sample. On the basis of X-ray diffraction patterns, we confirmed that iron-silicon alloy which hcp and fcc structure and Fe3 S
are stable phases under subsolidus conditions. Because of dissolution of silicon into iron, the boundary of fcc and hcp phase ofthis study shifts towards higher pressure compared to that of pure iron. Both solidus and liquidus temperatures are significantly
lower than the melting temperature of pure Fe and increases with pressure in this study. In addition, the present melting curve islower than the melting temperature of the Fe-Si system reported by Asanuma et al. (2010) and slightly lower than the eutectic
temperature of the Fe-Fe3 S system (Kamada et al., 2012) and that of the Fe-O-S system (Terasaki et al., 2011). In order todraw the melting curve as a function of pressure, we fitted the present results using the Simon’s equation. The obtained fitting
parameters are TmR =1277(6), a=116.1(21) and c=1.06(2) for the solidus and TmR =1582(13), a=127.9(48) and c=1.00(3) forthe liquidus. Because sulfur and silicon are the candidates for the light elements in the cores of Earth, Mars, and Mercury (e.g.,
Malavergne et al., 2007), the present results on the solidus and liquidus temperatures can be applicable to the core formation
processes in the Earth, Mars, and Mercury.
Keywords: Core, Melting relationships, Diamond Anvil Cell, Light elements, Fe-S-Si system

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SIT06-P06

Room:Convention Hall

Time:May 25 18:15-19:30

Sound velocity measurements of solid iron under high pressure and high temperature using an ultrasonic method
SHIBAZAKI, Yuki1∗ ; NISHIDA, Keisuke2 ; HIGO, Yuji3 ; IGARASHI, Mako4 ; TAHARA, Masaki4 ;SAKAMAKI, Tatsuya4 ; TERASAKI, Hidenori5 ; SHIMOYAMA, Yuta5 ; KUWABARA, Souma5 ; TAKUBO, Yusaku5 ;OHTANI, Eiji4
1

Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2 Department of Earth and Planetary Science, The
University of Tokyo, 3 Japan Synchrotron Radiation Research Institute, 4 Department of Earth and Planetary Material Sciences,
Tohoku University, 5 Department of Earth and Space Science, Osaka University
The Earth’s interior has been directly investigated by seismic wave propagation and normal mode oscillation. Based on thoseobservations, the distributions of density and sound velocity of the Earth’s interior have been estimated (e.g. PREM). The core,
which is located at the center of the Earth, is believed to consist of metallic iron with a certain amount of light elements, suchas hydrogen, carbon, oxygen, silicon, and sulfur. A large number of experiments on the compressibility of iron and iron-lightelement alloys have been carried out in order to constrain the abundances of the light elements in the core. In the past fifteen
years, the sound velocities of the iron and iron alloys have also been measured intensively at high pressure. Although the soundvelocity consists of longitudinal (VP ) and transverse (VS ) components, most discussions about the core composition have been
based on the only VP data because of the technical issues of the high-pressure experiments. In order to estimate the abundancesof the light elements more correctly, the precise measurement of VS as well as VP is necessary. In this study, we measured the
VP , VS , and density of solid iron under high-pressure and high-temperature conditions using an ultrasonic method, and X-ray
radiography and diffraction techniques.
Simultaneous ultrasonic measurements, and X-ray radiography and diffraction experiments were carried out at BL04B1 beamline, SPring-8 in Japan. High-pressure and high-temperature were generated using a 1500-ton Kawai type multi-anvil apparatus
installed at BL04B1 beamline. The experimental conditions were up to 7 GPa and 800 K (stability field of bcc-Fe). The Fe
powder or rod was used as the sample. Ultrasonic VP and VS measurements were performed using the pulse reflection method.
P- and S-wave signals with a frequency of 57 MHz and 30 MHz, respectively, were generated and received by a 10 degree
Y-cut LiNbO3 transducer. The sample was first compressed to the target pressure and heated up to the maximum temperature ineach press load in order to reduce the deviatoric stress. Then, we got the ultrasonic data, X-ray radiography image, and X-ray
diffractions from the sample and the pressure marker (MgO + hBN) at each about 150-200 K temperature step on decreasing
temperature.
Our high-pressure VP and VS data are good agreement with the previous ambient-pressure results measured using the same
ultrasonic method [Dever, 1972]. In contrast, our VP data are slightly smaller than the results obtained by high-energy resolution
inelastic X-ray scattering (HERIX) technique [Liu et al., 2014]. The values of both VP and VS at high temperature are lower
than the linear relationship of a velocity-density, i.e., Birch’s law, at room temperature, which is the same trend as the previous
HERIX result [Liu et al., 2014].

Keywords: high pressure, planetary core, iron, sound velocity

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SIT06-P07

Room:Convention Hall

Time:May 25 18:15-19:30

Synthesis of unsaturated hydrocarbons at the core-mantle boundary
BELONOSHKO, Anatoly1 ; LITASOV, Konstantin2∗ ; LUKINOV, Timofiy1 ; ROSENGREN, Anders1 ; BRYK, Taras3
1

Department of Theoretical Physics, Royal Institute of Technology, Stokholm, Sweden, 2 VS Sobolev Institute of Geology andMineralogy, Novosibirsk, Russia, 3 Institute for Condensed Matter Physics, Lviv, Ukraine
The origin of life on Earth converges to the problem of the origin of first organic molecules, so called ’blocks of life’. The
synthesis of complex organic molecules with C-C bonds is possible under conditions of reduced activity of oxygen or at a surfaceof catalyst via Fischer-Tropsch reaction (Kenney et al., 2002; Lobanov et al., 2013). It is clear, however, that such conditions
should have sustainably existed to provide continuous flow of large quantities of organic material. We found, performing ab initio
molecular dynamics simulations of the C-O-H-Fe system, that such conditions exist no deeper than at the core-mantle boundaryof the Earth. H2 O and CO2 can be delivered to the CMB by subducting slabs. Indeed, carbon and hydrogen can be also emitted
from the core itself. The mixture of H2 O and CO2 subjected to high pressure (130 GPa) and temperature (around 4000 K) does
not lead to synthesis of complex hydrocarbons. However, when metallic Fe is added to the system, C-C bonds emerge. Being
lighter than the material in the mantle, the hydrocarbons can rise towards the surface via mantle plumes as a part of fluid or melt
component, providing the ’blocks of life’ for further synthesis of complex organic molecules. Stability of hydrocarbon molecules
and their possible mobility as a light component of the plume was argued in recent study of peridotite and eclogite systems with
reduced C-O-H fluid (Litasov et al., 2014).Thus, the iron core not only protects Life on Earth creating the magnetic field, but may
also create the Life. This means that search for Life on other planets can also be oriented towards the planets with iron cores.
Keywords: high pressure, core mantle boundary, ab initio molecular dynamics, C-O-H fluid, hydrocarbons, iron

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