Benstonite (Ba6Ca6Mg(CO3)13) shows a characteristic cathodoluminescence (CL) in a red region, which can be assigned to an impurity center of divalent Mn ion. The wavelength of an emission band centered at 627 nm is slightly longer than those of emission bands in calcite and dolomite, suggesting its strong crystal-field (Dq) around Mn ion comparing with calcite and dolomite.
Zincite thin films were grown on Al2O3 substrate by pulsed laser deposition method. After the characterization, gas sensor properties were evaluated. In this paper, we discuss the relationship film character and sensor response.
In the Hakone district, there are two types of anorthite megacryst which are coloured yellow and colourless. Preliminary analysis by XPS had shown that iron in the yellow megacryst was ferric. Crystal structures of the above yellow and colourless anorthite megacrysts were refined from single crystal diffraction data in space group P-1 and I-1 respectively. Average T-O bond distances for both megacrysts suggested that Al/Si distributions in the T-site were highly ordered. In particular, the T1(0z00)-site in the yellow sample, the T-O bond distance was slightly longer and the isotropic temperature factor was just smaller than the other Al-sites. Judging from the compositional data (EPMA) and the structural evidence (XRD) it seems reasonable for ferric iron to enter T-site in the yellow one, and for ferrous iron into the M-site of the colourless sample. These results imply that a somewhat large and heavy cation occupies the T1(0z00)-site, namely, partial replacement of Al3+ by Fe3+. Thus, the colouration in the yellow anorthite megacryst was confirmed structurally.
Incorporation of Na+ and La3+ in CaSiO3 perovskite was experimentally investigated in the system of CaSiO3-NaLaSi2O6. High pressure and high temperature synthesis of Na+ and La3+ bearing CaSiO3 perovskite was performed by using the multi-anvil apparatus, ORANGE-3000 installed at GRC, Ehime University. Incorporation of Na+ and La3+ in CaSiO3 perovskite occurs through the coupled substitution mechanism of 2Ca2+⇔Na++La3+. Solubility limit of NaLaSi2O6 component in CaSiO3 perovskite is about 2.7 mol% at 20 GPa, 1300 °C and 4.4 mol% at 20 GPa, 1600 °C.
High-pressure phase transition in FeTiO3 was examined at pressure to 35 GPa and temperature to 1600 oC using a multianvil apparatus. The results indicated that at about 28 GPa FeTiO3 perovskite dissociates into the mixture of calcium-titanate type Fe2TiO4 and O1 type TiO2at temperature below 1200 oC, and into the mixture of calcium-titanate type Fe2TiO4 and FeTi2O5 phase above 1200 oC. These results are different from previous studies performed by laser-heated DAC. We disccuss on the difference of phase relations along with the fact that titanate perovskites do not transform to post-perrovskite but dissociate into two phases.
We determined pressure demendence on water solubility of Al-bearing bridgmanite. SIMS used for water measurement. Water contet of Al-bearing bridgmanite increased with increasing pressure between 25 and 32 GPa. Bridgmanite can contain water at least upper part of lower mantle.
We investigated the phase diagram of iron at high pressures and high temperatures using the laser-heated diamond anvil cell and the first-principles calculations. The transition boundary was estimated to be P(GPa) = 51 + 0.045 x T(K).
We performed ab initio molecular dynamics simulations of hexagonal-closed-pack iron to investigate its thermoelasticity in Earth's inner core P,T condition. Calculated elastic wave velocities are compared to seismological values. Based on the obtained results, we will discuss the inner core mineralogy.
The melting experiments indicate that the inner core of the Earth crystallized from the center of the molten core and have Si rich inner core with Si depleted and S enriched outer core. In smaller terrestrial planets, the core crystallized at the top of the liquid core during crystallization of the core. The solid inner core is depleted in both Si and S compared to liquid outer core.
The high-pressure polymorph of TiO2 rutile with the α-PbO2-type crystal structure have been found in rocks shocked by meteorites and ultra high pressure metamorphic rocks. In this study, isobaric heat capacity of α-PbO2-type TiO2 was measured by differential scanning calorimetry (DSC) and the thermal relaxation method using a physical property measurement system (PPMS) in the temperature range of 2-630 K. The obtained heat capacity yielded the standard entropy of 64.6±0.3 J/mol.K at 298.15 K.
High frequency resonant ultrasound spectroscopy enables us to measure single crystal elasticity of ~200 microm meter sample. In this talk, I would like to introduce the technique and boost the colaboration work using the technique in Mineralogical Community.
NaCl-B1 phase is representative pressure stanndard, thus many types of experiments were conducted to constrain models of equation of state. Boehler (1981) obtained data of Adiabats up to 5 GPa, however no model of equation of state based on quasi-harmonic approximation can reproduce the data at high temperartures. Intrinsic anharmonicity effects to lower the Gruneisen parameter at high temperatures, thus we challenge to reproduce the data of Boehler using equation of state based on intrinsic anharmonicity theory. However, the intrinsic anharmonicity model results in a slight improvement. Rapid disappearance of intrinsic anharmonicity in small compression relates this results.
We have conducted in-situ neutron and X-ray diffraction experiments on the hydrous silica glass at room temperature up to 10 GPa. Structure factors and radial distribution functions indicate that the intermediate range order of hydrous silica glass shrinks with increasing pressure, but the SiO4 tetrahedra does not change up to 10 GPa.
We have measured Mössbauer spectra from Fe3S and FeO under high pressure at BL10XU and BL11XU, SPring-8 in order to understand the interior of the Earth. 57Fe enriched Fe3S and FeO were loaded into a sample chamber of DAC. We have measured Mössbauer spectra of Fe3S during decompression from 30 to 5 GPa and room temperature and those of FeO were obtained at 200 GPa. The magnetic transition in Fe3S was observed between 20 and 25 GPa. Doublet peaks from FeO were observed. We will show the spectra of FeO at high temperature based on laser heating technique.
We report new high-pressure polymorphs of iron oxide Fe7O9 (Fe3+/Fe2+ = 4/3) and its Fe2+-Mg solid solution (Mg,Fe2+)3Fe3+4O9 synthesized at about 24-26 GPa using a multi-anvil press. Single crystal X-ray diffraction (XRD) studies showed that the crystal structures of both Fe7O9 and (Mg,Fe2+)3Fe3+4O9 have monoclinic C2/m space groups, that differ from any other known lattices of iron oxides. Mössbauer spectra are in agreement with the crystal structure refined from single crystal XRD. This newly found Fe7O9 polymorph suggests that iron oxides may have more variable mixed valence state under high-pressure condition than previously thought.
Intermediate-depth earthquakes are seismic activities in Wadati-Benioff zone at depths from 60 km to 300 km, where subducting plates deform plastically rather than brittle failure. To conduct quantitative and simultaneous measurements of quantitative flow data, reaction kinetics, and AE activities, we have carried out syndeformational antigorite dehydration experiments at high pressure.
Old oceanic limestone variety can be found by fine re-crystallized limestone layers and/or buried blocks. Japanese case of the Akiyoshi (Yamaguchi) reveals both remnants, whereas the latter case is found as impact evidences of re-crystallized calcite and veins with quenched iron-carbon aggregates with recent Fe-ASEM observation and micro-Raman data.
Katoite, Ca3Al2(O4H4)3, is one of the Nominally Anhydrous Minerals (NAMS) that are an important reservoir for hydrogen in the Earth’s crust and mantle. We report single-crystal X-ray diffraction and high-pressure Raman spectroscopic studies of katoite. Two lattice modes at about 330 and 540 cm-1 are observed in the Raman spectra. Increasing rate of full width half maximum (FWHM) for lattice modes were varied at 6 GPa, which is interpretable as a cubic-tetragonal phase transition. The results indicate that the structural phase transition of katoite occurs from cubic (Ia-3d) to tetragonal (I41/acd) at about 6 GPa.
We conducted shock compression silica gel and investigated structural changes by XRD analysis and IR and Raman spectroscopy. The shock experiments were performed at 20 GPa under cryogenic condition (100 K) and ambient condition (293 K). As a result, structure of silica gel approach to silica glass structure and is dehydrated at ambient condition. On the other hand, at 100 K, prominent structure changes and dehydration phenomenon were not confirmed. These results suggeste that structure of silica gel is influenced by experimental temperature as well as shock pressure under the shock compression of 20 GPa.
P-V-T equation of state for epsilon-FeOOH was determined from in situ X-ray diffraction experiment at pressures to 11 GPa and temperatures to 700 K. A fit to the second-order Birch-Murnaghan equation of state yielded isothermal bulk modulus K0, 300K = 143(8) GPa, the volumetric thermal expansion coefficient 2×10-5 K-1, and the temperature dependence of bulk modulus (dK/dT)P = -0.02 GPa/K.
We report in situ Raman spectroscopic studies of magnetite in a diamond-anvil cell under hydrostatic conditions up to 40 GPa at room temperature. With increasing pressure, the frequencies of the three modes A1g, F2g and Eg increase continuously up to about 24 GPa with pressure derivatives of 2.7, 4.5 and 1.4 cm-1/GPa, respectively. Upon elevation of pressure to nearby 30 GPa, the F2g mode starts to display a variation in the spectra and its intensity gradually decreases due to the cubic-orthorhombic phase transition. The split mode into B1g, B2g, B3g from F2g completely disappears at a pressure of 30 GPa.
Recently, it is reported that ice VII can incorporate salt into its crystal structure. In this study, we investigated incorporation of MgCl2 into crystal structure of ice VII. Pressure was applied to MgCl2 solution up to 6 GPa using diamond anvil cell (DAC) at room temperature and X-ray diffraction pattern and Raman spectra were obtained. Phase boundary between ice VII and ice VIII and OH stretching frequency of ice VII suggested the incorporation of MgCl2 into crystal structure of ice VII.
Experimental results of high-temperature creep of polycrystalline Fe-bearing olivine have been used to understand the upper mantle rheology. In this study, we synthesized Fe-bearing olivine (Mg1.8Fe0.2SiO4) aggregate by using a new method and investigated the effect of impurities on the strength of olivine aggregate. Deformation tests on doped 0.1wt% Al2O3, CaO, NiO, TiO2, or both Al2O3 and CaO) samples showed no major difference in their strength under diffusion creep. Further, we found that Fe-bearing aggregate exhibited one order of magnitude lower strength compared to Fe-free olivine aggregate.
We calculated the thermoelastic property of lower-mantle compositions by first principles calculations. The results shows that a pyrolitic composition can reproduce the reference velocities and densities. In this presentation, I am going to report that solid solution effect of Fe2+ and Fe3+ on the thermoelastic property of MgSiO3 bridgmanite of the calculations. The result of solid solution effect of Chantel et al (2012) plotted between our result of Fe2+ and Fe3+. Chantel et al (2012) used a sample including Fe2+ and Fe3+. Therefore, this study confirms Chantel et al (2012)
Our understanding of uranium mobility in the deep subsurface is limited, as exemplified by an unexpected finding of high concentrations of uranium in reducing deep granitic groundwater at a Swedish geological disposal site. As Japan is located at tectonically active plate boundaries, geological factors influencing the mobility of uranium remain to be carefully clarified. We studied core samples from the Mizunami underground research laboratory (URL) to reconstruct long-term changes in uranium mobility in deep granitic rocks by analyzing calcium carboante precipitaed from seawater during the Miocence marine transgression.
Weinvestigated YREE fractionation between granitic groundwater and fracture filling calcite at the depth of -200 to -500 m at the Mizunami Underground Research Laboratory, Tono area, Central Japan for understanding YREE behavior in the deep granitic media.
The vials containing two-line silica-ferrihydrite and iron-reducing bacteria were incubated in the dark at 30 ºC for up to two months. Si-bearing magnetite and iron-rich sheet silicate with ~0.7 nm spacing and were formed. We confirmed that iron-reducing bacteria can change two-line silica-ferrihydrite to sicilian magnetite and greenalite-like clays, which are both common in the least-metamorphosed Banded Iron Formation.
Ferrihydrite is transported in groundwater and river with adsorbed metals, and is metastable and is transformed to stable phases, which affects metal redistribution at the Earth’s surface. We transformed ferrihydrite with adsorbed Zn of different concentrations to understand the changes in transformation rate and Zn redistribution between different concentrations. The initial Zn concentration significantly has affected the transformation rate and process, and Zn redistribution.
Some hazardous elements caused the water pollutions exist as anionic species. We have investigated the development of remediation scheme of these species by using the transformation of metastable phases. Monohydrocalcite is metasble phase and transforms to calcite or aragonite with time. We found that the dissolved arsenate was removed during the transformation process.
The complex was made by aniline and montmorillonite, We attempted to desorb aniline from the aniline and montmorillonite complex to use aquatic solution at pH 1, 4, 8 and 12, and deionized water. At pH 4 and 8 and deionized water, aniline was hardly desorbed from the complex. At pH 1, about 50% aniline removed from the complex and at pH 12, about 90 % aniline was desorbed from the complex. We are trying to re-adsorb aniline by montmorillontie which desorbed aniline. We will show the detail in our presentation.
Earth's mineral crystals are final products in Earth materials system, whereas human beings are final life products of Earth surroundings. Both products are some excellent cases of changed sustainability at active Earth system with different time and site factors. Global water system produces the sustainable changes for both material systems. In this sense, recent minerals and human life might be found only at Earth-type circulatory system with global ocean water.
To understand the mineralogical difference between biominerals and their geological or synthetic counterparts, the lattice constants of aragonite and its transition temperatures to calcite by heating in various biotic, geological and synthetic aragonites have been measured. Among 21 aragonite specimens, the axial ratios for six marine molluscan species are considerably larger than those of abiotic ones but three fresh-water species and three land snails have similar axial ratios. On the other hand, almost biotic aragonites showed a transition temperature 60-100C lower than geological and synthetic ones, but the shells of land snails showed almost the same transition temperature.
Interfacial structure of calcite/salt water interfaces was investigated by using X-ray crystal truncation rod (CTR) scattering measurements. A sample cell was developed for observing the effect of elevated temperature on the structures. The effect of temperature and dissolved ions in the solution was discussed by comparing the results with an adsorption experiment.
Cs-adsorption experiment of clay minerals was conducted to reproduce the actual contamination level in Fukushima, using Cs-137 radioisotope and IP autoradiography. Various clay minerals were immersed together in dilute Cs-137 solutions (10-11 to 10-9 M) and the amount of Cs-137 adsorbed in each mineral was measured by IP autoradiography. Cs-137 was predominantly fixed in the weathered biotite collected in Fukushima compared to the other clay minerals, supporting our previous result that weathered biotite was dominantly found as radioactive soil particles in Fukushima.
Microparticles containing substantial amounts of radiocesium collected from the ground in Fukushima were investigated mainly by transmission electron microscopy (TEM) and X-ray microanalysis with scanning TEM (STEM).
Monohydrocalcite (MHC) is one of the hydrous Ca carbonates, and rare mineral in geological settings. We revealed the formation condition of MHC by synthesis experiments. Also we suggested that MHC require the paragenesis of hydrous Mg carbonates. In this study, we conducted the synthesis experiments MHC and amorphous Mg carbonates (AMC) and XAFS measurements to clarify the speciation of Mg associated with MHC.As a result of XANES measurements and pattern fitting, we suggested that MHC have two type of Mg, as the mixture of AMC at outside of MHC and Mg inside of MHC like Mg of aragonite.
Selenium is toxic element. Selenium exists selenate(SeO42-) or selenite(SeO32-) in solution. Magnesium oxide(MgO) is metastable phase, converts to brucite(Mg(OH)2) or hydromagnesite in aqueous solution. MgO has very high sorption capacity of arsenite in solution(Liu et al. 2011). Sorption experiments were conducted with 2μM of selenite and 0.01M of NaCl, 2g/L of material loading for 3-60h. Suspension were measured pH, liquid phase were measured Mg,Ca and Se concentration and mineral phase of solid were identified at each time. MgO showed efficient removal of selenite. We considered that sorption mechanism in this case is probable coprecipitation process during MgO convert to Mg(OH)2.
2 line ferrihydrite affects the regulation of element cycling in natural environments by adsorbing trace elements. bacterial iron reducing process can release adsorbed elements. We investigated the fate of arsenate and zinc adsorbed on two-line ferrifydrite during bacterial-iron reduction.
We investigated the effect of soil bacteria on plagioclase weathering, especially its crystallinity, morphology, and chemical composition, by using TEM-EDS analysis. Some albite fragments attached with bacteria for 4 days were observed. The SAED patterns show that the surface crystallinity of the albite particles was maintained. The Na/Si ratios in the albite particle attached with bacteria were relatively lower than those of pure albite. The results suggest that Na can be leached by the bacteria from the albite particles which still maintain its crystallinity and morphology.
This study is aimed to elucidate the mechanism of silica diagenesis from opal-AG to quartz. Diatoms collected from Lake Yogo, Siga prefecture were cultured in laboratory. The structure of the diatom was investigated by synchrotron X-ray scattering analysis and HP HT Raman spectroscopy. X-ray scattering analysis showed a typical broad diffraction pattern indicating opal-AG. The HP HT Raman spectroscopic analysis showed that structure of the diatoms was transformed to opal-CT just after heating and compression. With further heating and compression, it was transformed to moganite and a-quartz. This is approximately consistent with the silica diagenesis observed in sedimentary rock.
We investigated the relationships among mineralogy, structural features of organic material, and the highest temperatures during atmospheric entry in micrometeorites (MMs) recovered from Antarctic snow. Nine MMs investigated are comprised of 4 anhydrous MMs and 5 hydrated MMs. We estimated the highest temperatures based on the solar flare tracks, phyllosilicates, and carbonates. The highest temperatures were estimated to be >600 oC for anhydrous MMs and <600 oC for hydrated MMs. The structure of organic material is also different between two groups of MMs. The results suggest that they were originated from parent bodies with quite different orbital elements.
In order to constrain the formation conditions of chondrules, a number of reproduction experiments have been performed. A gas jet levitation method was employed in Nagashima et al. (2006). In this study, we performed experiments to reproduce the textures of radial pyroxene chondrules using the gas jet levitation furnace used in Nagashima et al. (2006). The textures similar to natural radial pyroxene chondrules were reproduced at the cooling rates of about 105-106K/hr and crystal growth rate of 0.1-0.01mm/sec. These experimental data insist chondrule formation event is about 10-100sec and would lead to a discussion on the chondrule formation.
Based on our recent studies of the Mokoia CV3 carbonaceous chondrite, we propose a model for the development of the Mokoia lithology through formation of chondrules/rims and fine matrix grains by fragmentation in different regions in the parent body, followed by transportation, mixing, and accumulation in a fluid state, and finally lithification of those objects. These processes may have been repeated, cyclically, within the parent body.
In order to elucidate the behavior of chondrite toward aqueous fluid, we report hydrothermal alteration experiments of Allende meteorites. Experiments were carried out at 200 deg.C and 15 bar for 168 hours with different pH solutions and different water/rock ratios. The recovered samples were analyzed by SEM-EDS, SR-XRD, and TEM. As results, in all 12 runs,serpentine formed as a main secondary phase at interstitial space of olivine grains in the matrices. The present study indicate that hydrated mineral formation under a reducing ambient easily proceeds compared with the previous studies.
We measured reflectance spectra of 17 CM carbonaceous chondrites under vacuum using a FT-IR spectrometer and investigated relationships between the degree of aqueous alteration and properties of 3µm and 0.7µm absorption bands that are related to hydrous minerals. In this study, we show that it is possible to characterize to some extent the degrees of aqueous alteration of C-complex asteroids using reflectance spectroscopy.
We have observed 281 samples of ordinary chondrites in NIPR collection under optical microscope, and classified them into several groups of breccia. Here we propose our preliminary classification system for brecciated ordinary chondrites.
Y 982717 has been classified as an anomalous H chondrite because of its very low Fa and Fs values (Fa10.6-13.3, Fs9.6-14.4). Refractory lithophile abundances and O-isotopic compositions are similar to those of ordinary chondrites. We conclude that Y982717 is the lowest-FeO H chondrite found to date and indicates that the H chondrites are more compositionally diverse than has been previously recognized.
The vales of Wo and Fs components were read along isotherms on the quadrilateral diagram of pyroxene at 1 atom presented by Lindsley (1983), fifty points for each OPx and CPx region. Regression equations of temperature for CPx and OPx are as follows: T(CPx) = 860.9 - 1.548*Wo^2 + 70.55*Wo + 0.3166*Fs^2 – 23.51*Fs, T(OPx) = 601.9 – 14.60*Wo^2 + 227.3*Wo – 0.1587*Fs^2 – 1.708*Fs. Multiple correlation coefficients and standard errors are 0.998 and 10.1 °C for CPx and 0.998 and 11.5 °C for OPx. In order to determine Wo and Fs components of CPx, correction for kosmochlor (NaCrSi2O6) is also proposed.
The equilibrium form of olivine was discussed based on Ab initio calculation. Olivine crystal morphology is important to understand H2 molecules formation in the space and the water origin of the Earth. In this study, the equilibrium form was tried to obtain from morphologies of negative crystals in olivine of LL5-LL6 equilibrated chondrites using micro X-ray tomography. Negative crystals in the Tuxtuac meteorite have similar morphologies, suggesting that they almost correspond to the equilibrium form although the most well-developed facets are (100) surface, which has high surface energy. We will also report results on the Kilabo, Y-75258 and Y793214 meteorites.