Photocatalitic materials have been recognized as one of important materials related to environment and energy. Oxide semiconductors, such as TiO2, ZnO have been investigated. In this study, we paid attention to the combination of smectite and ZnO for a novel photocatalytic materials, which will cover the negative point of ZnO, that is, photodegradation in solution. We have investigated the photocatalytic activity of smectite which substitute Zn in octahedral sheet.

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Growth textures and twin boundary structures of quartz twinned after Japan Law were studied by observations of etch figures and cathode luminescence, and molecular dynamics (MD) simulations. Near the composition plane of Japanese twin, hourglass-shaped sectors are observed to have mosaic textures composed of polysynthetic Brazil twin. This sector corresponds to a growth sector of {10-11} or {01-11}, where the composition plane is smooth and flat {11-22}. From the MD simulations, it is shown that {11-22} is the only composition plane that does not incorporate dislocations, and that dislocations are not required at a junction of Japanese and Brazil twin boundaries. These facts indicate that {11-22} composition plane of Japanese twin serve as a source of Brazil twin during the course of growth.

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We studied the morphology and growth process of the +X and -X faces of synthetic quartz crystals using AFM and FTIR. The differences in the morphology and H2O content between them indicate that adsorption of H2O on the -X face changed the property of the –X face.

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Laser-cut surfaces of single and polycrystalline diamonds were examined by scanning and transmission electron microscopies. The laser-processed grooves are filled with debris materials composed of textually different types of layered carbons: (i) highly oriented, highly crystalline graphite layer, (ii) oriented microcrystalline graphite layer, and (iii) non-oriented nanocrystalline graphite layer, from the basal (unaltered) diamond surface to the center of the grooves. The observation suggests that the pulsed-laser ablation of diamonds occurs via two-step process: (1) graphitization of laser-irradiated diamond surface, followed by (2) sublimation and oxidation of carbon materials.

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Anisotropy of IR light transmission in Calcite

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Enhancement of dissolution rate of amorphous silica by interaction with amino acid molecules

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The effect of partial pressure of atmospheric oxygen on Fe(II) oxidation rate was examined. We found that the Fe(II) oxidation rate deviates from the linear dependency of partial pressure of atmospheric oxygen and that the deviation is larger at lower partial pressure of atmospheric oxygen. Our results suggest that atmospheric oxygen levels in the Precambrian are overestimated if the Fe(II) oxidation rate with the linear dependency of partial pressure of atmospheric oxygen is applied to paleosols.

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Adsorption and immobilization mechansims of heavy metal elements to weathered soil have been investigated by artificially contaminating the soil with lead (Pb). EPMA analyses of the soil kept in a wet condition for two years showed local concentration of Pb in several microns areas. Thin specimens were prepared from the areas using FIB and investigated by TEM. The host minerals for the concentration are probably smectite and/or micaceous minerals. Manganese always coexists with Pb in the area.

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The contamination of groundwater with dissolved cationic chemical species such as Ni, Cu, Zn, Cd, Hg, and Pb has been an important concern in the past. Dissolved anionic species such as As has received a more important focus due to its prevalence in West Bengal as a toxic contaminant affecting several hundreds of thousands of people. Nitrates and phosphates from excessive use of fertilizers in agriculture and detergents in households are grim reminders of dissolved anion contamination in rural groundwater supplies. Chemical weathering of slag and fly ash recycled as cement materials can release anionic chemical species that has alarmed the industrial community. Long-lived dissolved anionic nuclides such as ¹⁴C, ³⁶Cl, ⁷⁹Se, ⁹⁹Tc and ¹²⁹I from radioactive wastes of the nuclear power industry are also a cause for grave concern. The behavior of dissolved anionic chemical species in the natural environment has proved to be the most important factor in determining their hazards and their accumulation in minerals that comprises rocks and soils. In this context, this paper presents a review of the chemical speciation of hazardous inorganic anions in groundwater. It is one of main objectives of the manuscript to depict and understand anion mobility at different pH and redox conditions in the natural geochemical environment. A substantial part focuses on adsorptive behavior of the anions onto goethite as the representative adsorbent in the natural environment. Finally, the management strategies involved in controlling hazardous inorganic anions in the natural environments, i.e., natural remediation strategies of anions, are comprehensively reviewed and discussed. The final part is reinforced by several examples of natural attenuation processes in governing the anion mobility.

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As a result of delays in the improvement of the sewerage system in rural areas of Japan, waste -water disposal facilities remain woefully inadequate in many of these areas. Consequently, waste-water is often dumped directly into rivers. This practice is the primary cause of river water pollution in the Japanese countryside. Various attempts are now being made on a local scale to purify such waste river water using simple methods. In the present study we have attempted to remove the ammonium ions contained in waste river water using natural zeolites in an oxidative atmosphere by means of a laboratory-scale circulatory apparatus. The ability of zeolite to purify waste-water was compared, under the same experimental conditions, with that of regular river gravel, which has no ion exchange ability. Three kinds of natural zeolites obtained from different areas in Japan were used, and their characteristics and their ability to purify such kinds of waste river water were compared with one another.

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Stacking disorder in a sedimentary kaolinite specimen with Hinckley-index close to one, was investigated mainly by TEM and its correspondence with powder XRD pattern and low-temperature FT-IR was discussed. Selected-area diffraction (SAD) shows 0kl or hhl patterns of various features, from completely discrete to heavily streaked along the c* direction, depending on individual grains. HRTEM images indicate that stacking defects are mainly caused with disorder of the alternative lateral interlayer shifts, t₁ and t₂ between adjacent layers. There is a tendency that this disorder forms isolated stacking faults (for instance, single layer with t₂ shift in a matrix with t₁ shift) rather than a mixture of enantiomeric blocks. Besides, disorder by the existence of C layers, or dickite-like stacking sequence, was also observed. Furthermore, the h0l SAD patterns occasionally have streaks.

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The interlayer cations distribution modes for K-NH4 dioctahedral mica series and the resulting I-T(illite-tobelite) intersratified system are an interesting topic as noted by Drits et al.(1997). XRD simuration for various I-T interstratified system of random, ordered and segragated types have been made in this study. These interstratified structures cause the characteristic broadening of the 005 reflection and therefore are determined by the reflection peak width ratio of the both 005 and 002 refelctions against the interlayer NH4 ratio (or I/T ratio). Many natural K-NH4 mica series samples have been investigated to test and verify such XRD determinative criteria for I-T interstratified system. Hydrothermal mica clay minerals associated with Roseki deposits (Japan) and tin-vein deposits (Bolivia) are of intermediate nature between random and ordered I-T interstratified models.

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Surface chemistry and morphology of goethite prepared at various temperatures were investigated to elucidate the effect of production temperature on the surface properties. It was found that goethite prepared at low temperature was extremely small. X-ray photoelectron spectra revealed that production temperature affect the surface chemistry of the synthetic goethite.

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On identifying the phytolith of the leaves, XRD method is often used. Unless any process is performed, dried and powdered leaves are mostly consist of small fragments of cellulose and amorphous silica. They cause the great amount of background intensity which obscures the small diffracted peaks. Trial experiments for the reduction of these great noises were done applying the centrifugal separation and the decomposition of cellulose by the enzyme "cellulase". The process for Thelypteris viridifrons, a kind of common fern, gave successful result. Although no diffracted peaks had been observed for the non-processed samples, many peaks were revealed after the centrifugation and the decomposition of cellulose, which belonged to whewellite and weddellite. These processes were demonstrated to be very useful for the study of phyto-biomineralogy.

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SS in the inflow river is rich in clay and Fe, but poor in Ca in the summer in contrast to the winter. In the summer, rice pad supplies many clay and Fe. SS in the Kasumigaura-lake is rich in clay and SiO2, and poor in Ca and Fe. The chemical change of SS from the inflow river to the lake is originated from the difference of pH between the inflow river water and the lake water. Moreover, this change is derived from the breeding of diatom.

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We have monitored secular variation of stream water chemistry in the Tanzawa Mountain catchment from 2001 to 2008. Ph-values of the water samples show well-defined oscilating variation having a 4 years period. The data suggest that this chemical variation is well correlated to the seismic activities observed in the Taanzawa Monatain.

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Altered biotite in weathered granitic rocks from Tamura-shi, Fukushima Prefecture, northern Abukuma Mountains, Japan, is studied. Biotite in the study area is divided into two groups by magnesium and iron contents as a result of analysis of chemical composition of major elements using SEM/EDX. Only a small change of Mg value has been observed until potassium content is as half as the fresh biotite, but it decreased when potassium content was less than half of the original value. Hydrobiotite is found in biotite with higher magnesium content as a result of powder XRD. Irregularly mixed layer mineral of biotite and vermiculite is identified instead of hydrobiotite in biotite with lower Mg value. Crystallinity is considered very low because peaks of mixed-layered minerals were very broad.

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Mineralogical and geochemical analysis were performed on mudstone sedimented on the Kuroko deposits, which were formed ca. 13Ma. Detailed size analyses of framboidal pyrite suggest that (1) bottom oceans became anoxic and euxinic right after the Kuroko formation; and (2) bottom oceans became oxic a few million years later. These are corresponded to sulfur isotope compositions of pyrite. In the euxinic ocean water, complicated microbial mediation of sulfur occurred resulting in very negative sulfur isotope compositions. In later stage, simple sulfate-reduction in sediments was responsible for pyrite formation.

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In this study, we treat the problem that As-contaminated groundwater in Vietnam. The core sample in the As-contaminated groundwater area in Vietnam was mineralogically analyzed and was performed SSE technique. As a result, it is thought that the As-contamination mechanism with the highest possibility is reduced dissolution of the Fe-oxyhydroxide. Moreover, it found that this Fe-oxyhydroxide is related to biotite as a result of the TEM-EDS analysis. From these analysis results, we present the model of the groundwater arsenic elution in Vietnam.

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There is no research focused the characteristic for solid acid of minerals mineral surfaces is changed by relative humidity control. When the activation of catalysis on mineral surfaces is considered, water must be controlled and relative humidity can play this role. This may be a key to find out mechanism of peptide formation on mineral surfaces. It showed that the mineral catalysis for amino acid polymerization changed controlling relative humidity and Hectorite was the most effective catalyst. The factor that the catalytic efficiencies differ from each clay minerals may be the composition rather than the structure of clay minerals. As Hectorite is Mg- O in the structure, I conducted relative humidity experiment with Periclase. Mg-O may be the catalytic site to amino acid polymerization.

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REE phosphates in Pronto paleosol (2.45 Ga age) were analyzed by SEM-EBSD, SEM-EDS and FIB-TEM in order to understand their formation mechanisms. Monazite (-Ce,Nd,La) and rhabdophane (-Y,Gd,Dy) were observed to co-exist, and there was not obvious, crystallographical relationship between the two. It is suggested that the two minerals were formed during weathering and that rhabdophane (-Ce,Nd,La), more unstable thermally, was transformed to monazite while rhabdophane (-Y,Gd,Dy) has remained. Therefore, Ce in monazite (-Ce,Nd,La) can be useful for the estimation of atmospheric oxygen evolution.

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In Pinctada fucata, there are many investigations of its shell structure. However, most of them are for matured shell, and there are few investigations of larval shell. Therefore, we investigated larval shell by SEM, and TEM with FIB for sample preparation. 12h after artificial insemination inorganic shell was not observed, but 18h after, the embryo was completely covered with aragonite shell in which high density of (110)twin was formed. On the other side, in 48h, calcite large crystals were identified inside the aragonite shell.

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Fish otolith is calcium carbonate polycrystalline body containing organic matter including protein. It was reported that teleost sagitta and lapillus are made by aragonite, and astriscus is made by vaterite. Sagitta , lapisus and astaricus are ones of fish otolith. But other studies about teleost fish proved that many factors cause generation of differ crystal polymoph in sagitta. In this study, characteristics of aragonite and vaterite in sagitta were studied by thermogravimetry and differential thermal analysis. In the result, sagitta aragonite show 710K exothermic peak without variation in weight. In other hand, sagitta and synthesis vaterite show 740K exothermic peak in common. Those results suggest that there are some characteristics that specific to sagitta.

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Coccolith is a biologically, environmentally and geologically attractive biomineral produced as a calcified scale of marine unicellular algae, coccolithophores. Each coccolith consists of several tens of calcite crystal units that are interlocked together to form a ring or disk of 1-10 m in diameter with elaborate species-specific morphology. Pleurocrysis carterae are composed of interlocked V- and R-units which represent the calcite crystals with sub-vertical and sub-radial orientations of the c-axis, respectively. In order to elucidate the formation mechanism of coccoliths, we observed morphology of immature coccoliths of Pleurocrysis carterae, using a high-resolution FE-SEM and determined the crystallographic orientations applying EBSD technique. Furthermore, we performed morphological analyses by combining EBSD with SEM stereo-photogrammetry.

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Mineral phase identification of the coral skeletal microstructure is important for reconstructing the paleo-climate. Especially, chemical composition of Porites sp. is widely used as a paleo-environment variant. For example, it is believed that Sr/Ca ratio in coral skeletons is sensitive to temperature of seawater. Recently, Greegor et al. (1997) reported that as much as 40% of strontium (Sr) in coral aragonite existed as a SrCO₃ end member by using XANES and EXAFS. This should be a very serious problem, when we apply the Sr/Ca ratio to reconstruct the paleo-environment. However, since there has been no direct mineral identification of SrCO₃, we have carefully observed Porites sp. by FE-ASEM and ATEM in order to identify mineral phases in the coral skeletal.

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The high-pressure behaviors of pure iron and iron alloys have been investigated by both high-pressure experiments and first-principle calculations. In the case of pure iron, the magnetic transition from antiferromagnetic to non-magnetic state was confirmed at 60 GPa. Iron oxide and iron sulfide also showed the magnetic transitions at high pressures. The transition pressure of iron oxide was higher than that of pure iron. The magnetic transition of iron sulfide was accompanied by the structural phase transition.

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We have investigated the stability of Fe₃C-cementite at high pressure and high temperature, because there has been a little knowledge about that. In the 2007 annual meeting, we reported a preliminary result that Fe₃C may be transformed into Fe₇C₃ + Fe at high pressure and high temperature. However, it was strange that we observed not Fe but FeO in the run products. We used NaCl as thermal insulating material in a diamond anvil cell (DAC). Since it is known that NaCl often adsorb H2O, it may cause the oxidation of Fe. Therefore, we used different thermal insulating materials (Al₂O₃ and CaSiO₃) in order to see some effects of those thermal insulators.

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X-ray diffraction experiments have been performed on amorphous Fe78B13Si9 by using diamond anvil cell at BL13A of Photon Factory. Structure factor S(Q) can be derived from X-ray diffraction pattern, ant it is optimized by Fourier transform method. The peaks of S(Q) at 9 GPa shifts toward higher Q in comparison with that at 0.1 MPa, implying the amorphous iron alloy is compressed. On the other hand, the correlation function of amorphous iron alloy at 9 GPa is not different much from that at ambient condition.

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Coupled enrichments of ¹⁸⁶Os/¹⁸⁸Os and ¹⁸⁷Os/¹⁸⁸Os have been reported in some plume magmas, and this anomaly may be produced by the partition behavior of Re, Pt, and Os between metallic iron and metallic liquid. The anomaly may be formed by contamination of about 1 wt. % of the outer core metallic melt, i.e., the isotopic anomaly is as the outer core signature. The results of partitioning experiments of Re, Pt, and Os between iron and Fe-S melt at high pressures revealed that the nearly chondritic ratios of Re/Os and Pt/Os are expected by the crystallization of the metallic iron. Thus, the Os isotopic anomaly observed in some plume basalts may not be a product of contamination of the outer core material at CMB

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Density of magma at high pressure is one of the most important properties to understand magma migration in the planetary interior and the differentiation of the terrestrial planets. The density measurements of magma have been carried out by several methods (shock compression experiments and sink-float method in static experiments, etc.). However, since these methods have difficulties in acquisition of data at a desired pressure and temperature, the density of the silicate melt have been measured under only a few conditions. Recently a new density measurement was developed by the X-ray absorption method. Advantage of this method is to measure density of liquids at a desired pressure and temperature. In the present study we measured the density of peridotite magma by X-ray absorption method. Experiments were carried out at the BL22XU beamline at SPring-8. A DIA-type cubic anvil apparatus was used for generation of high pressure and temperature. We used tungsten carbide anvils with the top anvil sizes of 6 mm. The energy of monochromateized X-ray beam was 23 keV. The intensities of incident and transmitted X-ray were measured by ion chambers. The density of the melt was calculated on the basis of Beer-Lambert law. The starting material was a crystal with the pyrolite composition. Experiments were made from 1 atm to 5 GPa, from 300 to 2100 K.

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The viscosity of silicate melt of NaAlSi₂O₆ composition was measured at pressures from 1.6 to 5.5 GPa and at temperatures from 1350 to 1880°C. We employed in situ falling sphere viscometry by using X-ray radiography. We found that the viscosity of NaAlSi₂O₆ melt decreased with increasing pressure up to 3.6 GPa at 1780±10°C. By using the relationship between the logarithm of viscosity and the reciprocal temperature, the activation energies for viscous flow were calculated to be 3.7±0.5 * 10^2 and 3.6±0.5 * 10^2 kJ/mol at 2.2 and 2.9 GPa, respectively.

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We have measured electrical conductivity of partially molten model peridotite. The model peridotite consists of forsterite with basalt and carbonate without iron. Conductivity was measured using a cubic anvil apparatus with a deformation function and Solartron 1260 impedance analyzer. The measurement conditions are 1600 K and 2 GPa. The shear strain speeds are 6 × 10^-7 and 2 × 10^-6 /s. We have found that conductivity in the shear direction is one order of magnitude higher than that normal to the shear direction. The magnitude of anisotropy in conductivity is independent of shear velocity. The magnitude of anisotropy is independent of the strain rate. These experimental results suggest that the observed highly anisotropic conductivity is explained by partially molten peridotite under shear conditions.

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Behavior of Xe-SiO2 system under high pressure and high temperature was studied using diamond anvil apparatus. When SiO2 crystal was heated in Xe at about 1 GPa using laser-heating technique, considerable amount of Xe remained in a sample which was recovered to ambient condition, although no sign of the formation of Xe compound was obtained by X-ray or Raman techniques. SEM observation indicates that this Xe was stable even after heating the recovered sample to several hundred degrees centigrade in air. TEM observation clarified that the Xe was trapped a few microns beneath the surface of SiO2 crystal. The mechanism of the formation of such texture will be discussed.

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A mineral composition of the upper mantle and transition layer is discussed. The discassion is made using Vp/Vs ratio of the elastic wave velocities of the mantle. The Vp/Vs ratio of the seismic wave distributions in the mantle is carefully estimated. The Vp and Vs models in the mantle are derived independently, so to get an accurate estimation of Vp/Vs ratio in the mantle Vp and Vs models must be chosen very carfully. Recent advancement of seismological research has made accurate estimation of Vp/Vs ratio possible. Recent experiments on elastic wave velocities has made possible to compare the Vp/Vs ratio in the mantle and those of mantle minerals. The comparison made in this study shows the mineral composition in the upper mantle is peridotitic, and that in the transition layer is eclogitic.

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High pressure experiments and calorimetric measurements were performed to clarify the stability field of CaAl4Si2O11 CAS-phase. It was shown that CAS-phase is stable above about 13 GPa and 1100°C. Combining the measured enthalpy data with published ones, dissociation boundary of CAS-phase into a mixture of Ca-perovskite, corundum and stishovite was calculated. Assuming reasonable geotherms, it was concluded that CAS-phase is stable in the transition zone and upper part of the lower mantle.

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Pressure-induced spin transition of ferric iron in Mg_0.85Fe³⁺_0.15Al_0.15Si_0.85O₃ perovskite was examined by X-ray emission spectroscopy (XES) at SPring-8. The obtained XES pattern indicates that the spin state of ferric iron changes from high spin to intermediate spin between 50 and 80 GPa and the intermediate spin state continues up to 113 GPa. This intermediate spin state of ferric iron can be explained by the crystal field splitting energies of 3d electrons of ferric iron at the distorted dodecahedral site in perovskite.

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Si and O diffusion rates on polycrystalline (Mg,Fe)2SiO4 wadsleyite and ringwoodite have been determined at pressures between 16 to 22 GPa and temperatures between 1673 to 1873 K. The results show that Si diffusion rates is slower than O diffusion rates and previously reported Mg-Fe interdiffusion rates in both (Mg,Fe)2SiO4 wadsleyite and ringwoodite. Consequently, Si is likely to be rate-controlling species in high-temperature creep.

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Many hydrous phases should exist in the subduction zone, and serpentine is a main hydrous phase in the hydrous peridotite layer of the descending slab. Antigorite (Atg) is one of the polymorph of serpentine, and it has been studied for stability field and phase relation. As the result, it has been clarified that the dehydration of Atg brings free water into the mantle wedge and promotes partial melting. Above ∼5 GPa,the breakdown of Atg produces phase A (Mg₇Si₂H₆O₁₄;11.8 wt% H₂O), and the subducting slab is able to transport water to deep mantle.However, the subducting slab is considered to be very low temperature,and the dehydration of Atg should occur at very low temperature. This indicates that the kinetic effect should be important for the dehydration of Atg in the Earth's interiors. In this study, time-resolved dehydration experiments of Atg were conducted by in situX-ray diffraction using the high-pressure apparatus "MAX80" at KEK to evaluate the dehydration rate of Atg.

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Nucleation and growth kinetics of the post-spinel transformation in Mg2SiO4 have been examined under nominally dry condition by time-resolved X-ray diffraction measurements using energy dispersive method. Our results combined with previous studies under wet condition suggest that water greatly enhances both nucleation and growth rates in the post-spinel transformation. Kinetics of this transformation is important for understanding the depression of the 660 km seismic discontinuity.

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Chromium K-edge X-ray absorption near-edge structure (XANES) spectra of natural ferropericlase were measured using X-ray microbeam from a synchrotron radiation source to estimate the valence state of Cr. These samples were inclusions collected from the lower mantle diamonds. The obtained results first revealed that divalent chromium are present in the materials from the lower mantle and the Cr2+ proportion to the total Cr content varied among the samples. Chromium K-edge XANES observations on inclusions in diamonds will be a potential redox indicator for the lower mantle.

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High pressure-temperature experiments of olivine-methane were performed at 5.5 to 29.4GPa and 1200K to 2200K to examine stability of methane and formation of hydrocarbons. Diamond anvil cell combined with Nd-YAG laser and CO₂ laser heating systems was used. XRD patterns showed that existence of olivine and their high pressure phases, solid methane were observed. Formation of ethane molecules was observed in the Raman spectroscopy. The Raman spectra of the recovered samples showed C-H vibration mode, assigned as long polymerized hydrocarbons. Graphite and glassy carbon were also observed. The results suggest that methane molecules partly dissociate, and dissociation proceeded to form pure carbon phases and hydrogen atoms in the Earth's mantle condition.

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Hydrogen hydrate is considered to be one of the major constituents of protostar, icy planets and their moons. A known high-pressure structure of hydrogen hydrate, filled ice Ic, is maintained to 60 GPa and shows the outstanding stability. In this study, the phase changes of hydrogen hydrate were clarified and the reasons for the remarkably stabilized structure with regard to the intermolecular interaction were examined. High-pressure experiments revealed that the suppress of the rotation of hydrogen molecules and partly extracting of hydrogen molecules occurred at around 20 GPa. These phenomena might occur in order to moderate unfavorable state caused by the close arrangement, leading the stability. At around 35 GPa, symmetrization of the hydrogen bond in the host water molecules occurred.

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We have measured the T-P-V data of Pt at high temperatures between 800 and 1600 K, and high pressures between 21 and 42 GPa, using synchrotron powder X-ray diffraction experiments at Spring-8. Both a Kawai-type multi-anvil high pressure apparatus with sintered diamond anvils and a laser-heated diamond anvil cell were used to measure higher T-P data of Pt. Combining these measured high P and T data with previously reported 300 K volume compression data, and using the Mie-Greuneisen type thermal pressure analysis, we present the T-P-V EOS of Pt, as a reliable pressure calibration standard at high T and P conditions up to 3000 K and more than 150 GPa.

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We measured the compressibility of FeAlO3-bearing perovskite and the spin state of ferric iron in perovskite using synchrotron X-ray. The spin state of ferric iron was 5/2 (high spin) at 50 GPa and 3/2 (intermediate spin) at 80-113 GPa. Although no large discrepancy found in the unit cell with increasing pressure, the isothermal bulk modulus significantly smaller than that of MgSiO3 perovskite.

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Elastic wave velocities of grossular garnet were determined up to 16.4 GPa and 1650 K in conjunction with in situ synchrotron X-ray measurement. We obtained marked increase in elastic wave velocities after heating to 1000 ˚C above ~10 GPa. The elastic wave velocities after heating to 1000 ˚C are ∼1-1.5 % higher than those of original grossular sample, which are comparable to previously reported elastic wave velocities of grossular. In contrast, we observed no change in X-ray diffraction patterns collected in situation, and need further detailed investigation for clarifying the cause of the marked increase in elastic wave velocities.

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In situ X-ray diffraction experiments of phase D have been conducted to confirm its stability and compression behavior under the lower mantle conditions by using a combination of multianvil apparatus and synchrotron radiation. Sintered diamond anvils were used to achieve pressures up to 46 GPa and temperature up to 1300 K. High temperature EOS for phase D was derived from obtained X-ray diffraction patterns.

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Trace elements abundance of the mantle source regions is useful information to decipher the material circulation and transfer during the Earth's history. We carried out reaction experiments between basalt and olivine aggregates at 1-3 GPa and 800-1100°C in order to investigate the mobility of trace elements in olivine aggregates derived from basalt source and to understand the behaviors of the incompatible elements in the upper mantle conditions.

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In order to construct metastable mineralogy of subducting oceanic crust (MORB), mechanisms and kinetics of the eclogite-garnetite transformation were examined at 11 GPa and 1000-1550 ˚C using synthesized MORB eclogite as a starting material. SEM observations indicate that small grains of majoritic garnet are formed along grain boundaries of clinopyroxene, however the original pyropic garnet metastably survives even at the highest temperature of 1550 ˚C. Present results suggest that the density of MORB is affected by the kinetics of the eclogite-garnetite transformation.

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We have carried out compaction and deformation experiments on two-phase mixtures of H2O and CO2 ices at 170-220K and up to 120 MPa, and 160-190K and up to 50 MPa, respectively. Preliminary results show that the flow strength of two-phase mixtures is near the average between uniform stress and uniform strain rate models. When the stiffer H2O ice contains 20 vol.% of the weaker CO2 ice, the viscosity of the two-phase mixture decreases by less than half of that of the pure H2O ice.

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Temperature measurement in large volume press experiments has been based on thermocouple emf, which has well known problems, e.g., unknown pressure dependence of emf, chemical reaction between thermocouple and materials related on cell assembly, and so on. There have been several attempts to measure temperature in large volume press experiments using techniques other than thermocouples. Here we report a new development using pyrometry in the multianvil press, where temperatures are derived on the basis of spectral radiometry. Several high pressure runs were conducted using the 1000 ton press with a DIA module installed at 13 ID-D GSECARS beamline at Advanced Photon Source (APS). The cubic pressure medium, 14 mm edge length, was made of soft-fired pyrophyllite with a graphite furnace. A moissanite (SiC) single crystal was built inside the pressure medium as a window for the thermal emission signal. An MgO disk with 1.0 mm thickness was inserted in a gap between the top of the SiC crystal and thermocouple hot junction. The bottom of the crystal was in direct contact to the tip of the anvil, which had a 1.5 mm diameter hole drilled all the way through the anvil axis. An optical fiber was inserted in this hole and the open end of fiber was in contact with the SiC crystal. Thermal spectral radiance from the inner cell assembly was obtained via the fiber and recorded by an Ocean Optics HP2000 spectrometer. The system response of spectrometer was calibrated by a tungsten ribbon ramp (OL550S, Optronic Laboratories, Inc.) with standard of spectral radiance. The cell assembly was compressed up to a target load of 15 tons, which was close to ambient pressure and then temperature was increased up to 1573 K. Radiation spectra were mainly obtained above 873 K and typical integration time was 1 ms. Two different calculations were made to derive temperature based on pyrometry. One was made based on Planck radiation function and the other was made by the J-function which is defined based on Wien's law (Yagi and Susaki, 1992, High Pressure Research: Application to Earth and Planetary Sciences, eds., Y. Syono and M.H. Manghnani, pp. 51-54). Calculated temperatures above about 1200 K were generally consistent with those obtained from the thermocouple emf within less than about 25 K. In addition to these measurements, new results using smaller cell will be also discussed.

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