Search

High -pressure single crystal X -ray diffraction studies of a natural chondrodite, Mg4.76Fe0.22Ti0.02Si1.99O8 (OH1.26F0.74), and a synthetic OH -chondrodite, Mg4.98Si2.01H2.00O10, were performed using a diamond anvil cell (DAC) up to 7.3 and 5.9 GPa, respectively and at room temperature. FT-IR spectra of the natural chondrodite under high -pressure conditions up to 9.9 GPa was also observed using a DAC. The axial linear compressibili- ties of these samples are calculated as β a = 1.69(4) × 10 −3 , β b = 2.98(4) × 10 −3 and β c = 2.74(5) × 10 −3 (GPa −1 ) for the natural chondrodite and β a = 2.11(18) × 10 −3 , β b = 2.83(18) × 10 −3 and β c = 3.04(38) × 10 −3 (GPa −1 ) for the synthetic OH -chondrodite. The isothermal bulk moduli of these samples were calculated as KT = 124.1(4) GPa for the natural chondrodite and KT = 117(2) GPa for the OH-chondrodite, by using the Birch-Murnaghan equation of state assuming K' = 4. The bulk moduli of total void space in each sample, assuming K' = 4, were calculated to be K□ = 116(2) GPa for the natural chondrodite and K□ = 113(4) GPa for the OH-chondrodite. The plots of bulk modulus versus the summation of the filling -factor of polyhedral sites show a good correla- tion between the humite minerals. This relationship can be explained by the replacement of 4O 2− + Si 4 + ⇔ 4(F, OH) − + □ generated in the humite homologous series. In the FT-IR spectra of the natural chondrodite, four OH -stretching vibrational peaks were observed at 3688, 3566, 3558 and 3383 cm −1 under ambient condi- tions. The pressure dependences of the frequency of these peaks up to 9.9 GPa are 2.8(3), 3.9(3), 4.0(3) and −2.1(2) (cm −1 GPa −1 ), respectively. With increasing pressure up to 9.9 GPa, the 3383 cm −1 peak shifts to lower- frequency positions, whereas the other peaks shift to higher-frequency positions. The shortening of the O5⋅⋅⋅ O5 distance, which is not the shared edge between M3 octahedra, related to hydrogen bonding with increasing pressure causes the negative pressure -dependence of the 3383 cm −1 peak. The positive pressure -dependence of the remaining IR -peaks is due to the compression of the O5 -H bond, and not related to hydrogen bonding with increasing pressure.

Recently mineral scientists have paid attention to the neutron scattering, because some intense pulsed neutron sources have been constructed or in planning in the world. In Japan, the High Energy Accelerator Research Organization (KEK) and the Japan Atomic Energy Research Institute (JAERI) have jointly constructed a 1 MW pulsed neutron source (JSNS) at Tokai, Ibaraki. The neutron and the x-ray diffraction should provide complementary information each other because of their physical properties. For example, light elements like hydrogen are almost invisible for x-ray and it is difficult for x-ray to distinguish neighboring elements in the Periodic Table such as Mg, Al and Si, which are major elements in geological materials and often show interesting order-disorder relating phenomena. However, neutron expects to provide useful information about those invisible problems of x-ray since the scattering cross-section of neutron is independent of the atomic numbers. In this paper, we will give an overview of elastic neutron scattering and give some ideas of mineral physics at high pressure and high temperature. In addition, we will shortly introduce the JSNS and our proposal of a high pressure/temperature material science station in the JSNS.

At present, neutron diffraction experiments at high pressure up to 20 GPa are available only at a spallation neutron source in ISIS, Rutherford Appleton Laboratory, UK. Experimental procedures and techniques for measuring neutron diffraction at high pressure are reviewed in this article. In addition, recent achievements on structural determinations of hydrogen-bearing materials at high pressure are reviewed.

We investigated the applicability of Raman microprobe spectroscopy for determining the density of CO2 in fluid inclusions in minerals of mantle-derived xenolith samples. A separation (delta) between two Raman bands of CO2 due to Fermi resonance can be a reliable densimeter for CO2 fluid. The relationship between the density of CO2 (g/cm3) and delta (cm-1) can be expressed as: d = -0.03238697 delta 3 + 10.08428 delta 2 - 1046.189 delta + 36163.67. This equation was obtained from the Raman data on CO2 fluid with densities from 0.1 to 1.21 g/cm3, including super critical fluids at 58-59 degrees C. The delta value was constant with increasing temperature from room temperature to 200 degrees C. This indicates that the Raman densimeter is not affected by a possible rise in temperature, an artifact induced by the high flux of the incident laser. The minimum size of measurable inclusions is 1 micron, and the precision in the determination of delta is 0.1 cm-1, corresponding to 0.02 g/cm3 for inclusions of 1 micron in size. The precision can be better for larger inclusions. The micro-Raman densimeter can determine the density of CO2 fluid inclusions over a wide range. In particular, densities of gas and mixtures of gas and liquid phases, which cannot be measured by microthermometry, can be determined.

In-situ synchrotron X-ray powder diffraction experiments on goethite were performed up to 24.5 GPa using a diamond-anvil cell at BL-18C in the Photon Factory, Japan. The compression behavior of goethite is anisotropic: the a axis, which is close to the direction of the hydrogen bond, is almost twice as compressible as the b and c axes. A second-order Birch-Murnaghan fit (K' = 4) to the unitcell volumes and pressures up to 24 GPa gave a bulk modulus K0 = 111(2) GPa. The pressure medium apparently affects the compression behavior of goethite, as a sudden strain broadening occurs above 11 GPa, where solidification of the 4:1 methanol:ethanol pressure medium occurs. The crystal structure of goethite was refined by means of the Rietveld method at several pressures below 10 GPa. The main compression occurs in the “vacant channels” in the crystal structure, where the OH◊◊◊O bridges are located. The hydrogen-bonded O◊◊◊O distance shortens with increasing pressure at the rate of about -0.023 A/GPa and reaches 2.60(1) A at 9 GPa.

The pressure-induced structural phase transition in kalicinite, KHCO 3 , has been studied by neutron powder diffraction, and infrared (IR) and Raman spectroscopy at high pressure and room temperature. The neutron diffraction study of deuterated kalicinite (KDCO 3 ) revealed that for the one site for hydrogen (deuterium) found in the low-pressure phase, the O-D...O angle decreases from 176 to 161° and the distance between donor and acceptor O atoms of the O-D...O group decreases from 2.66 to 2.59 A in the pressure range from 0 to 2.5 GPa. The crystal structure of the high-pressure polymorph was not determined. Infrared spectra were obtained at pressures up to 6.3 GPa using a diamond anvil cell. At ambient pressure, the O-H stretching, O-H...O in-plane bending, and O-H...O out-of-plane bending modes occur at 2620, 1405, and 988 cm - 1 , respectively. The frequency of the O-H stretch mode was nearly constant in the pressure range from 0 to 2.8 GPa, while that of O-H...O in-plane bending and out-of-plane modes increased with increasing pressure up to 2.8 GPa and remained constant above the phase transition pressure. The Raman spectra showed a clear phase transition at 2.8 GPa. The three Raman modes observed are assigned to internal vibrational modes of HCO 3 - and this suggests that the surrounding environment did change dramatically at the phase transition. These results suggest that the phase transition in kalicinite is triggered by the distortion of C-O-H bond at high pressure.

Mid infrared throughput using 5 μm apertures was investigated using micro-FTIR spectrometers with conventional light sources at two laboratories and the synchrotron radiation infrared (SR-IR) light source at SPring-8. With both the light sources micro-FTIR microscopy can analyze the fundamental O-H vibration in andesitic glass with 1 weight % H2O through 5 μm apertures. Spectra obtained at SPring-8 show better relative standard deviations due to the brighter and more highly collimated nature of SR-IR compared to conventional light sources. The spectra with 100 and 1000 scans at SPring-8 have similar relative standard deviations to those with 1000 and 10200 scans, respectively, at laboratories. The successful analysis with 5 μm apertures using both light sources shows the potential for an improvement in the spatial resolution of micro-FTIR analyses.

A single crystal high-pressure X-ray diffraction study of phase A was performed using a diamond anvil cell up to 11.2 GPa at ambient temperature. The chemical formula of this sample, determined by EPMA from an average of 18 data points, was Mg6.99Si1.99H6.06O14. Axial linear compressibilities of phase A were βa=2.92(2) and βc=2.17(3) (×10-3/GPa). The isothermal bulk modulus, calculated using the Birch-Murnaghan equation of state, was KT0=105(4) GPa with a pressure derivative K′=3.9(8) and V0=512.2(6) A3. The bulk modulus correlates with the summation of the filling factor of the tetrahedral site and the octahedral site, as shown for the minerals on the forsterite-brucite join in the system MgO-SiO2-H2O.

The specimen used in this study was a single crystal of phase-A Mg6.99Si1.99H6.06O14 synthesized using a multi-anvil apparatus at conditions of 1000°C and 10 GPa. Sets of x-ray diffraction intensities were measured with a single crystal of 60 × 50 × 30 μ m using synchrotron radiation up to 9.4 GPa. The unit-cell parameters observed gave K0 = 105 GPa (assuming that K' = 4). With increasing pressure, significant decreases of O–O distances for hydrogen bonds were observed.

In situ synchrotron X-ray diffraction measurements were performed on kalicinite (KHCO 3 ) up to 9.0 GPa at room temperature. A reversible phase transition was observed at about 2.8 GPa. The structure of the high-pressure phase has not been identified yet. The compression behavior of kalicinite is highly anisotropic and the a -axis is about two times more compressible than the b - and c -axes. The compression behavior is different from that during contraction in lowering the temperature and this suggests that the hydrogen bonded O⋯O distance is significantly shortened with increasing pressure.

Fourier-transform infrared (FT-IR) spectroscopy was applied to examine human serum very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) in aqueous solution and in solid film for characterizing lipid components. On the basis of the FT-IR second-derivative spectra for standard samples of triglycerides, cholesterol esters and phospholipids, it was found that the band at 1746 cm −1 for VLDL and the band at 1738 cm −1 for LDL were mainly due to the unsaturated triglycerides and unsaturated cholesterol esters, respectively. The implications of ester CO stretching bands are discussed.

Micro-Raman spectroscopic analysis allows us to estimate the internal pressure of small fluid inclusions. We applied this method to CO2-dominated fluid inclusions in mantle-derived xenoliths. The pressures estimated from the equilibration temperature and density of the fluid range from 0.96 to 1.04 GPa corresponding to depths of up to 30 km, which confirms that these rocks and fluids are of uppermost mantle origin. Furthermore, the inclusions show pressures specific to the individual host minerals (spinel≥orthopyroxene≈clinopyroxene≫olivine). In particular, the densities of CO2 in pyroxenes are 10% higher than in olivine. Such an enormous difference cannot be explained by elastic deformation of the minerals during ascent of the xenoliths, although the process may explain the slightly higher density of CO2 in spinel. During the ascent, the strain rate of orthopyroxene calculated using the ‘constitutive equation’ is several orders of magnitude lower than that of olivine. The difference in densities of CO2 among the host mineral species is therefore attributable to the rheological properties of the minerals. Present internal pressures of fluid inclusions can be a sensitive strength marker of mantle minerals. Conversely, the density of CO2 inclusions in pyroxene (and spinel) may be a useful geobarometer.

A new high-pressure phase transition of pyridine at 5.0 GPa was found using Raman and IR spectroscopy. Application of pressure over 20 GPa induced irreversible polymerization of pyridine, and a yel...

A composite material of amorphous calcium carbonate and aspartic acid (Asp) was synthesized using a highly concentrated solution of calcium aspartate: a new approach. A transparent and amorphous solid with approximately 1 mm thickness was obtained. UV–vis transmittance spectrum of the composite shows no characteristic absorption in visible region. A Raman spectrum of the composite revealed a peak assigned to the symmetric stretching of carbonate ion. This study demonstrated that amorphous calcium carbonate could be stabilized using not only organic artificial macromolecules but also using Asp, a small biomolecule. This result is expected to engender development of new biomimetic materials.

Oligomerization of benzene at high pressures up to 16 GPa was investigated at room temperature using an opposed-anvil type pressure apparatus. The recovered samples were analyzed using GC-MS to identify and quantify the products after the high-pressure experiments. Some structural isomers of benzene dimer as well as biphenyl, naphthalene, and terphenyl isomers were detected at pressures higher than 13 GPa. The molar yield of the polycyclic aromatic hydrocarbons increased concomitantly with increasing pressure, although benzene still remained. The oligomerization is likely to occur when the neighbor distance of the benzene molecules exceeds the threshold of the reaction distance. The oligomerization is regarded as a precursory phenomenon of the amorphization that occurs at higher pressure.

The nature of protons in ice VII up to 368 °C and 16 GPa was investigated with synchrotron near-infrared spectroscopy. The absorption band of the first OH stretching overtone mode divided into doublet peaks above 5 GPa at room temperature, suggesting that proton tunneling occurs at the overtone level. As the temperature increased, the doublet peaks gradually reduced to a singlet. This result implies that thermally activated protons hop between the two potential minima along the oxygen–oxygen axis. A pressure–temperature diagram for the proton state was constructed from the changing band shape of the overtone mode.

International audience; Three kinds of ceramics, zirconia-toughened alumina (ZTA), alumina-toughened zirconia (ATZ) andyttria-stabilized zirconia (YSZ), were tested as anvil materials, mainly for the purpose of neutron scatteringstudy under high pressure. ZTA with non-toroidal anvil profile, having the same sample volumeas conventionally used double toroidal anvils, sustained pressures up to 11.9 GPa. This is comparable toanvils made of tungsten carbide (TC) with Ni binder with the same dimensions. ATZ would also be analternative material to TC with pressure performance comparable to ZTA, whereas YSZ is much weakerthan the other two ceramics. The attenuation coefficient for YSZ is significantly smaller than that of TCand similar to ZTA and ATZ, the latter being estimated by attenuation calculations. Neutron diffractionon a sample of lead in YSZ anvils as well as quasi-elastic neutron scattering on liquid water in ZTA alsodemonstrate the outstanding neutron transparency of these ceramics. The gain factor in count rate is up toone order of magnitude.

FTIR spectroscopy has been applied to study the coordination structures of Mg2+ and Ca2+ ions bound in Akazara scallop troponin C (TnC), which contains only a single Ca2+ binding site. The region of the COO- antisymmetric stretch provides information about the coordination modes of COO- groups to the metal ions: bidentate, unidentate, or pseudo-bridging. Two bands were observed at 1584 and 1567 cm-1 in the apo state, whereas additional bands were observed at 1543 and 1601 cm-1 in the Ca2+-bound and Mg2+-bound states, respectively. The intensity of the band at 1567 cm-1 in the Mg2+-bound state was identical to that in the apo state. Therefore, the side-chain COO- group of Glu142 at the 12th position in the Ca2+-binding site coordinates to Ca2+ in the bidentate mode but does not interact with Mg2+ directly. A slight upshift of COO- antisymmetric stretch due to Asp side-chains was also observed upon Mg2+ and Ca2+ binding. This indicates that the COO- groups of Asp131 and Asp133 interact with both Ca2+ and Mg2+ in the pseudo-bridging mode. Therefore, the present study directly demonstrated that the coordination structure of Mg2+ was different from that of Ca2+ in the Ca2+-binding site. In contrast to vertebrate TnC, most of the secondary structures remained unchanged among apo, Mg2+-bound and Ca2+-bound states of Akazara scallop TnC, as spectral changes upon either Ca2+ or Mg2+ binding were very small in the infrared amide-I' region as well as in the CD spectra. Fluorescence spectroscopy indicated that the spectral changes upon Ca2+ binding were larger than that upon Mg2+ binding. Moreover, gel-filtration experiments indicated that the molecular sizes of TnC had the order apo TnC > Mg2+-bound TnC > Ca2+-bound TnC. These results suggest that the tertiary structures are different in the Ca2+- and Mg2+-bound states. The present study may provide direct evidence that the side-chain COO- groups in the Ca2+-binding site are directly involved in the functional on/off mechanism of the activation of Akazara scallop TnC.

The effect of lanthanum ion on the crystallization of calcium carbonate was investigated using CaCl2–NaHCO3 solutions. A sampling vessel enabling us to sample a small aliquot of a solution at any time almost under a closed condition was invented for the experiments. The abundance of the crystallographic polymorphs in the precipitate was determined by powder X-ray diffraction. The formation of calcium carbonate from lanthanum-doped solutions can be featured by three stages: a spontaneous and rapid precipitation of vaterite, a transitive static stage and a delayed formation of calcite. Almost all lanthanum (> 95%) in the solution system (dissolved + suspended solid phases) was proved to be incorporated in the initially formed vaterite, and lanthanum in the vaterite seemed to be immobilized throughout the experiment. The presence of lanthanum in the starting solution (10-4 of calcium in mole) stabilized the initial vaterite crystal, preserved it much longer than one month and increased the solubility of CaCO...

Near infrared absorption (NIR) spectra of natural morphologically cubic polycrystalline diamonds (cuboid) were obtained at room temperature, and the stretching plus bending combination band of molecular water was observed. The spectrum consisted of the main band at 5180 cm-1 due to liquid water and a shoulder at 5000 cm-1. The 5000 cm-1 band suggests the presence of a phase with stronger hydrogen bonding in inclusions in the diamond. This shoulder absorption decreased on heating to 120°C. The combination band of H2O at high pressure and temperature was measured using a resistively heated diamond cell and the pressure dependence of the peak position was obtained. Comparison with the present experimental results indicates that the spectral changes induced by heating of the cuboid corresponded to melting of a high-pressure form of ice, and the shoulder absorption at 5000 cm-1 arises from ice VI at 1.9 GPa. On the other hand, the liquid water, a main component of the fluid inclusions in the cuboid, was not under high pressure judging from the frequency of the combination band. This contrast might relate to the texture of the cuboid diamond. The spectral observation enables us to estimate the residual pressure of mantle fluid encapsulated in these diamonds. The diamond-cell data also provide high-P-T NIR fingerprint spectra that could be useful for identifying H2O phases and confining pressures in other samples.

Relative abundances of rare earth elements (REE) in geological materials are used widely to investigate diverse geochemical issues such as the origins of igneous rocks or the degree of stratification of water columns in oceans. One of the REE, cerium (Ce), can exist in either trivalent or tetravalent forms depending on the redox condition. Thus, knowledge of the oxidation state of Ce in rocks and minerals could potentially be used to constrain the redox states of past and present geological environments. However, the use of Ce for this purpose has been hampered by an inability to measure its oxidation state directly. Here, we present a new method, employing the X-ray absorption near-edge structure, for making such determinations in samples with Ce concentrations as low as 15 ppm. By analyzing a range of diverse geological materials (granites, manganese nodules and cherts), we showed that the method could identify significant differences in Ce speciation between materials formed under widely differing redox conditions. Used together with the degrees of Ce anomalies measured in REE patterns, this information has promise for refining our knowledge of various geochemical processes such as weathering, sedimentary and diagenetic processes that control the REE behavior. Such a refinement should in turn improve geological interpretations based upon REE data.

X-ray-absorption near-edge structure (XANES) was successfully applied for the direct determination of Ce valence in hydrogenetic ferromanganese nodules (two samples) and crust (one sample). Rare earth element (REE) patterns of the hydrogenetic ferromanganese nodules and crust recovered from the Pacific Ocean show large positive Ce anomalies, especially when normalized to seawater. Despite some disadvantages in the spectroscopic analysis of Ce in natural samples (e.g., low concentration and interference from other elements), intense synchrotron radiation and measurement of fluorescent XANES with semiconductor detectors having high energy resolution enabled us to detect XANES at Ce L III edge in the ferromanganese nodule or crust. In the XANES spectra of the nodule or crust, large double peaks were observed, showing that the oxidation state of Ce in the nodule or crust is predominantly tetravalent with little contribution from Ce(III). This is the first in-situ quantitative analysis of Ce(IV) among total Ce in natural samples as a trace element as far as we know. The results obtained by XANES seem to be consistent with the percentage of Ce(IV) estimated from seawater-normalized REE patterns, suggesting that seawater is a precursor of REE in the marine deposits. The present results also confirm that Ce enrichment relative to other REEs in hydrogenetic ferromanganese deposits is due to oxidative removal of Ce from seawater to the ferromanganese nodules and crust in the marine environment. Comparison of XANES spectra of Ce sorbed on synthetic manganese oxide and CeO 2 vs. those of the ferromanganese nodules and crust suggests that the initial reaction of Ce with the ferromanganese nodules and crust is the sorption of dissolved Ce(III) to the manganese oxide surface.

Neutron powder diffraction data of phase A (Mg7Si2O8(OH)6) were collected at ambient pressure and 3.2 GPa (calculated from the compressibility of phase A) from the deuterated compound, and the structure was refined using the Rietveld method. The derived crystal structure implies that hydrogen atoms occupy two distinct sites in phase A, both forming hydrogen bonds of different lengths with the same oxygen atom. This picture is supported by IR spectra, which exhibit two absorption bands at 3400 and 3513 cm−1 corresponding to OH stretching vibrations, and proton NMR spectra, which display two peaks with equal intensities and isotropic chemical shifts of 3.7 and 5 ppm. The D-D distance [D(1)-D(2) distance] at ambient pressure was found to be 2.09 ± 0.02 A from the neutron diffraction data and 2.09 ± 0.05 A from the NMR spectra. At 3.2 GPa, there is no statistically significant increase in the O-D interatomic distance while the hydrogen bonding interaction D···O appears to increase for one of the hydrogen sites, D(1), which has the stronger hydrogen bonding interaction compared with the other hydrogen, D(2), at ambient pressure. The O-D bond valences, determined indirectly from the D···O distances were 0.86 and 0.91 at ambient pressure, and 0.83 and 0.90 at 3.2 GPa, for D(1) and D(2), respectively.

Experiments have been carried out to clarify the effect of alteration on Re–Os system, near infrared (NIR)–infrared (IR) spectroscopic characteristics and polytype of a natural molybdenite mineral (MoS2). The molybdenite sample was placed in H2O and various media of 0.1 mol/L NaCl, NaHCO3, CaCl2, and AlCl3 solutions, and heated in a sealed quartz tube at a temperature of 180°C for 20 d. The unaltered and altered samples were subsequently used for analysis of Re and Os, NIR microscopic observation, and NIR–IR spectroscopy, and microfocus X-ray diffraction (XRD). Molybdenites subjected to NaCl and NaHCO3 solutions give younger Re–Os ages than that of the original unaltered molybdenite. No significant changes in d spacing and width of micro-XRD patterns can be found in these altered molybdenite, indicating the possibility of Re–Os fractionation without significant structural conversion of molybdenite mineral. These results strongly suggest that the Re–Os system in molybdenite would be frequently disturbed if it has experienced alteration, because alteration by the low salinity (

It is expected that high-pressure material science and the investigation of the Earth's interior will progress greatly using the high-flux pulse neutrons of J-PARC. In this article, we introduce our plans for in situ neutron powder diffraction experiments under high pressure at J-PARC. The use of three different types of high-pressure devices is planned; a Paris–Edinburgh cell, a new opposed-anvil cell with a nano-polycrystalline diamond, and a cubic anvil high-pressure apparatus. These devices will be brought to the neutron powder diffraction beamlines to conduct a “day-one” high-pressure experiment. For the next stage of research, we propose construction of a dedicated beamline for high-pressure material science. Its conceptual designs are also introduced here.

Neutron powder diffraction studies of \ensuremath{\beta}-Co(OD${)}_{2}$ to 16 GPa show that the structural changes with pressure are continuous and reveal no evidence for the amorphization of the hydrogen sublattice at 11 GPa previously proposed on the basis of light-scattering and x-ray diffraction studies [Nyugen et al., Phys. Rev. Lett. 78, 1936 (1997)]. Instead, the changes in the deuterium packing with pressure suggest that the observed anomalies in Raman and infrared data at 11 GPa are the result of structural frustration due to $\mathrm{H}\ensuremath{\cdots}\mathrm{H}$ repulsion.

— Concentrations of adsorbed water in single mineral grains of Antarctic lunar meteorites were determined with micro infrared (IR) spectroscopy. A relationship was found between the mineral's ability to adsorb water and the extent of Ce anomaly in rare earth element (REE) patterns precisely determined by the isotope dilution method using a thermal ionization mass spectrometer. Asuka (A) 881757, a lunar meteorite from the mare basalt without Ce anomaly, showed no trace of IR absorption due to adsorbed water. On the contrary, Yamato (Y) 791197-109, Y-86032-98, Y-86032-95, Y-791197-115 and Y-82192-55A from the lunar highland exhibiting positive Ce anomaly showed IR absorption due to adsorbed water in some of their minerals. The detected water would be of terrestrial origin, because it was not structurally bound and easy to exchange judging from the spectral band shape. The contrast in concentration of adsorbed water between the lunar highland and the mare basalt is derived from a difference in the density of microfractures in mineral grains. Average concentrations of adsorbed water in the lunar highland meteorites were 3.8 mg/cm3 for pyroxene and olivine, and 1.7 mg/cm3 for plagioclase. This contrast between minerals is noteworthy because it has been known that Ce anomaly of pyroxene and olivine is larger than that of plagioclase both for Antarctic lunar meteorites and some lunar rocks. Furthermore, more adsorbed water was detected for minerals in meteorites that exhibit larger Ce anomaly. The present observations demonstrate that the extent of Ce anomaly correlated with the concentration of adsorbed water, which suggests that active mineral surface resulting in adsorption of water could be a trace of interaction forming Ce anomaly. Terrestrial weathering on Antarctica and REE fractionation on the Moon are discussed for possible origins of the Ce anomaly.

The structures of the deuterated hydroxides (M (OD) 2; M=Mg, Ca, Mn, Ni, Co) have been refined using the Rietveld method and neutron powder diffraction data collected at high pressure. There is no statistically significant increase in the O-D interatomic distance at increased pressure while the hydrogen bonding interaction D. . . O increases as this distance decreases and the O-D. . . O angle increases. The intramolecular O-D bond valences, determined indirectly from the intermolecular D. . . O distances, decrease steadily for all materials as pressure is increased.

We carried out several analytical studies in order to determine the butanol distribution on a salol-butanol crystal. This work is required for a research using microgravity condition focused upon the in-situ observation with an interferometer of the temperature and concentration field for the organic transparent crystal (salol-butanol). In order to evaluate the concentration field for the liquid phase with an interferometer in case of crystal growth from solution in space, it is significant to determine the distribution of solute (butanol) on starting crystal before sample launching using a non-destructive analytical method. The Micro Raman Spectroscopy (MRS) was choice as the most appropriate analytical method among several analytical methods. We prepared a salol-butanol crystal enclosed into the 1mm thick quartz glass ampoule in order to verify the propriety for MRS. Obtained Raman spectrums for salol, butanol and salolbutanol crystal show that the butanol 2D-distribution on salolbutanol crystal can be determined by MRS. These results also demonstrate that there are no influences of thick glass cell upon measurements and that 3D-measurement is possible. In conclusion, we argue that MRS is the most appropriate method for determination of the 2D- and/or 3D- distribution of solute on the crystal among several non-destructive analytical methods.

A novel method is reported for growing large single crystals of diamond at high pressure and high temperature using a metallic solvent, by which high-quality crystals can be grown with a larger net growth rate. The growing space has a recess at its lower temperature side, and the seed crystal is located at the bottom of the recess. The seed grows to fill the recess, and its extended top surface serves as a large seed for the second-stage growth. The main part of the crystals grown in the second stage is found to have no or only few metallic inclusions when the size of the recess is selected appropriately. Experimental results show that the growth rate is small for the first-stage growth within the recess, but it becomes larger after the crystal grows out of the recess. The diffusion field of carbon in the solvent is simulated by numerical calculation, and the results can reasonably explain this nature of the growth process.

Water is a key material for the dynamics of the earth such as volcanic eruption and earthquakes. In particular, significant change in the mineral properties induced by the addition of water (hydrogen) is an intriguing research area closely related to behavior of hydrogen bonding at high pressure. Our recent progress on this field and future perspective are reviewed.

Tritium concentrations in Japanese precipitation samples collected after the March 2011 accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) were measured. Values exceeding the pre-accident background were detected at three out of seven localities (Tsukuba, Kashiwa and Hongo) southwest of the FNPP1 at distances varying between 170 and 220 km from the source. The highest tritium content was found in the first rainfall in Tsukuba after the accident; however concentrations were 500 times less than the regulatory limit for tritium in drinking water. Tritium concentrations decreased steadily and rapidly with time, becoming indistinguishable from the pre-accident values within five weeks. The atmospheric tritium activities in the vicinity of the FNPP1 during the earliest stage of the accident was estimated to be 1.5 × 10 3 Bq/m 3 , which is potentially capable of producing rainwater exceeding the regulatory limit, but only in the immediate vicinity of the source.

Laser-induced heating during micro-Raman spectroscopy, in some cases, gives rise to considerable down-shifts in Raman spectra of powder graphite samples. Employing the most typical experimental condition for graphitic matter of geochemical and/or cosmochemical interest, 10 mW laser power at the sample surface and ~2 μm laser beam, powdered artificial graphite samples revealed the E2g mode in low Raman peak position ranging from 1567 to 1576 cm−1. The energy range agrees very well with the previously reported frequency range for anomalously down-shifted Raman spectra of natural graphites. In order to extract spectroscopic information inherent in samples from the E2g frequency, it is essential to remove the laser-induced down-shift and to know the temperature of sample surface. We showed that the intensity ratio of the Stokes line to the anti-Stokes line for the E2g Raman band of graphite is potential to monitor the temperature of graphite surface. Furthermore, our measurement employing enough low laser power without laser-heating showed that natural graphite sample containing the rhombohedral polymorph exhibited the same G-band frequency as the E2g (1582 cm−1) frequency of hexagonal graphite. Thus, stacking sequences of graphite did not affect the intralayer vibrational energy.

Carbonado diamonds from Central African Republic exhibit very intense laser-induced photoluminescence due to the presence of the radiation damages. From the spectral profiles of photoluminescence obtained for these samples, the carbonado stones were grouped into three groups depending on a variation in the structure of radiation-damage products; Group-A carbonado with 504 nm band (3H band), Group-B carbonado with 575 nm band in addition to weak background peaks centered at 512 and 580 nm, and the Group-AB carbonado with features intermediate between Group-A and Group-B. When heating Group-A carbonado, Group-A was found to transform to Group-B at temperatures higher than 400°C. Thermogravimetry and Differential Thermal Analysis (TG-DTA) clarified the difference in thermal properties between Group-A and Group-B. While Group-A carbonado yields one intense and narrow exothermic peak at 800°C, Group-B carbonado exhibits a broad exothermic peak at 785°C. The distinct difference in the oxidation rate could be attributed to the difference in the density of micropores in carbonado. Chondrite-normalized rare earth element (REE) patterns for the bulk carbonado samples show negative Eu anomalies, and the inclinations of the patterns are similar to those of kimberlites and much steeper than that of continental crust as represented by continental shales. In the chondrite-normalized value, La/Lu ratios were of the order of 10 2 and the light REE abundances were as high as 10 3 relative to chondrite. Further, 1384 cm −1 absorption band was observed in IR (infrared) spectra of both Group-A and Group-B, which suggests the presence of nitrogen platelet in carbonado. These REE and IR results imply that the seed crystal of carbonado was formed at high pressure and high temperature and was subjected to the annealing process to generate nitrogen platelets. The genesis of Central African carbonado is discussed as a reconciliation of these experimental results.

Raman frequencies for the in-plane lattice vibration of graphite were surveyed for four Antarctic ureilites in order to construct a paradigm for structural properties of graphitic carbon in ureilites. Raman spectra were obtained by point-by-point measurements using a laser microbeam 1μm in diameter. The measured results formed an array in a two-dimensional plot between the E_ frequency and intensity ratio of two graphite-derived Raman bands. The graphitic matter in ALH-78019 gave the averaged E_ frequency at 1582.0 ⊿cm^, which agrees with the well-established wavenumber of the E_ in-plane lattice vibration of graphite. On the contrary, some graphitic matter in the ureilites (ALH-77257,Y-791538 and MET-78008) exhibited considerably up-shifted E_ frequency. Distribution in the array was proved to be closely linked to the extent of shock which the ureilites suffered.

[1] The existence of ferroelectric ice XI with ordered hydrogen in space becomes of interest in astronomy and physical chemistry because of the strong electrostatic force. However, the influence was believed to be limited because it forms in a narrow temperature range. From neutron diffraction experiments, we found that small hydrogen-ordered domains exist at significantly higher temperature and the domains induce the growth of “bulk” ice XI. The small ordered domain is named “memory” of hydrogen ordered ice because it is the residual structure of ice XI. Since the memory exists up to at least 111 K, most of ices in the solar system are hydrogen ordered and may have ferroelectricity. The small hydrogen-ordered domains govern the cosmochemical properties of ice and evolution of icy grains in the universe.

Publisher Summary In the Plesovice peridotite, several lines of evidence suggesting an ultradeep condition are found. All of these facts suggest that the Plesovice peridotite once resided in the diamond-stability field, which could not be identified by the previous geothermobarometric studies. This suggests that diamond was stable in the rock before Stage I (high-temperature spinel6garnet peridotite stage), which is the oldest generation of mineral assemblage previously recognized in the Plesovice peridotite. Furthermore, the presence of pyroxene exsolution lamellae in the earlier generation of spinel (Stage I) implies the preexisting high-pressure stage before Stage I. If graphite in MS inclusions were originally crystallized as diamond, parental fluids responsible for MS inclusion was most likely entrapped in the host mineral before Stage I, and they should have crystallized daughter minerals during the cooling/exhumation trajectory from the diamond-stability field, through Stage I, to the chlorite peridotite stage. For MS inclusions within Spinel-I, there is a good possibility original fluid/melt was entrapped in the diamond-stability field, if host Spinel-I was originally its high-pressure polymorph, Ca-ferrite, or Ca-titanite. On the other hand, one could not find the typical pyroxene exsolution texture in garnet. This probably suggests that most garnet was secondary formed at the expense of Spinel-I at relatively low-pressure condition. Therefore, if graphite in garnet was originally diamond, it is most likely that the diamond was graphitized before the entrapment within garnet crystal.

The distribution of rare-earth elements (REE's) between anhydrite crystal of calcium sulfate and its saturated solution was investigated at different temperatures. The lanthanide tetrad effect was observed as the apparent distribution coefficients. Furthermore, from the dependence of the apparent distribution coefficients on the growth of the anhydrite crystal, it was found that the process of the REE incorporation into the anhydrite crystal could be divided into two stages, namely, nonselective incorporation followed by thermodynamically controlled differential incorporation. It can be presumed that the factor affecting the extent of the tetrad effect depends effectively on the relative intensity of the two processes of incorporation of REE's into the anhydrite. This result would throw light on understanding of tetrad effects observed in various natural environments.

The fine structures of graphitic materials contained in four Antarctic ureilites (ALH-77257,ALH-78019,MET-78008 and Y-791538) were investigated using a laser light (514.5nm), which could be focused onto a spot of 1μm in diameter. Raman spectra obtained differ not only among individual ureilite samples, but also among positions within a single carbonaceous vein of the same specimen. Moreover, one can classify the carbon into several groups on the basis of the spectra concerned. For all samples, both well-ordered graphitic carbon and semi-ordered graphitic carbon were observed. Amorphous carbon was detected in ALH-77257 and MET-78008. The difference in structural ordering among the samples is attributed to the difference in distribution of the components of carbonaceous material, indicating minor difference in genetic conditions or in locality within the parent body. Structural heterogeneity of carbon within a single carbonaceous vein implies the occurrence of two (or three) types of carbonaceous matters which have fairly different physicochemical properties and distinct histories. For the genesis of the carbonaceous matter in ureilites, a two-stage model is proposed assuming the graphite crystallization from metallic phase followed by the inflow of semi-ordered graphitic carbon or amorphous carbon into the well-ordered graphitic carbon produced from the metal.

The natural garnets from chromite ores associated with pegmatoid pyroxenites of Sangalyk area (Uchaly ore district, southern Urals, Russia) were studied by means of micro-Raman spectroscopy. The compositions of these garnets were close to ugrandite, an isomorphous intermediate group of uvarovite-grossularite-andradite, X(3)Y(2)(SiO(4))(3), X = Ca(2+), Y = Al(3+), Fe(3+), Cr(3+), according to Raman spectra and X-ray microprobe analyses. An assignment of most of the observed bands in visible and near infrared Raman spectra is reported.

We investigated the applicability of micro-Raman spectroscopy for determining carbon isotopic compositions (13C/12C) of minute CO2 fluid inclusions in minerals. This method is nondestructive and has sufficiently high spatial resolution (1 μm) to measure each fluid inclusion independently. Raman spectra of CO2 fluid have 12CO2-origin peaks at about 1285 cm−1 and 1389 cm−1 (v12− and v12+) and a 13CO2-origin peak at about 1370 cm−1 (v13+). The relationship between carbon isotopic compositions and peak intensity ratios of v12+ and v13+ was calibrated. Considering several factors affecting the peak intensity ratio, the error in obtained carbon isotopic composition was 2% (20‰). The reproducibility of the intensity ratio under the same experimental environment was 0.5% (5‰). Within these error values, we can distinguish biogenic CO2 from abiogenic CO2.

A near-infrared (NIR) spectroscopic method is proposed to achieve the simultaneous determination of salinity and internal pressure of fluid inclusions in natural minerals. A combination band between the antisymmetric stretching and bending vibrations of molecular water at approximately 5180 cm−1 was observed for standard salt solutions and natural minerals containing fluid inclusions with known salinities. A curve-fitting procedure was used to analyze the change in the band shape of the combination. Justification of the calibration was confirmed by observation of fluid inclusions in natural minerals whose salinities had already been determined using microthermometry. The detection limit of the present method is 1 NaCl-eq wt. %. The minimum size of fluid inclusions that produced well-resolved spectra was approximately 30 μm. This method was applied to assess micro fluid inclusions in a natural diamond with cubic growth habit (cuboid). The salinity and residual pressure of those fluid inclusions were estimated respectively as 4.4 wt. % NaCl-eq and 0.6–0.8 GPa. The present method is complementary to Raman microscopy and microthermometry for the determination of salinity in fluid inclusions of geological samples.

In order to evaluate influence of water on the pressure and transition interval of the olivine-wadsleyite transition, synthesis experiments were carried out in hydrous Forsterite90 composition at 9-16 GPa and 1273-1873 K. Three additional starting materials, representing (a) Mg2SiO4 (b) San-Carlos olivine (Fo89) and (c) CaO-MgO-Al2O3-FeO-SiO2 peridotite, were loaded in every experimental assembly simultaneously. We observed significant expansion of olivine + wadsleyite stability loop to the lower pressure for 2-3 GPa at 1473 K, whereas there was no significant shift of the phase transition boundary at 1873 K. These results are consistent with thermodynamic calculations made by Wood and inconsistent with recent experimental data by Chen et al. We report here preliminary results on water content of coexisting phases. Water solubility of olivine increases with pressure up to 0.15 wt.% H2O at 14 GPa. At 12-15 GPa H2O content of olivine is almost the same at temperatures from 1373 to 1773 K, whereas the H2O content of wadsleyite decreases from about 2.1 wt.% at 1373 K to 0.7 wt.% at 1773 K. We determined the partition coefficient of H2O between two phases. Dwd/ol is 11.8 at 1473 K, 7.2 at 1673 K and 4.5 at 1773 K. However if wemore » apply recent calibration of H2O content in olivine by Bell et al. these Dwd/ol values are three times lower.« less

We report on the Raman spectra of water under high temperature and pressure conditions and show a discontinuity in the pressure dependence of the OH stretching frequency. As pressure increases, the strength of hydrogen bonding increases rapidly in the pressure ranges up to 0.4+/-0.1 GPa at 25 degrees C, 1.0+/-0.1 GPa at 100 degrees C, and 1.3+/-0.1 GPa at 300 degrees C and slowly above these pressures. This finding clearly demonstrates the existence of discontinuities in the pressure response of the hydrogen bonds of water, which suggests a possible structural change under these conditions.