Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences
2009 Annual Meeting of Japan Association of Mineralogical Sciences
Showing 1-50 articles out of 235 articles from the selected issue
S1: Water-rock interaction
  • Naotatsu Shikazono
    Session ID: S1-01
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Major element (Si, Al, Na, K, Ca, Mg, Fe, etc.) concentrations in groundwater are determined by rocks (minerals) interacting with rocks (minerals), degree of water-rock interaction, dissolution rate, precipitation rate and solubility of minerals, specific surface area of minerals, and flow rate of groundwater. In order to interpret groundwater quality variation, various theoretical models (chemical equilibrium, reaction kinetics, mass balance, reaction-flow coupling model) are used. Based on these models the variation of groundwater quality with altitude in basaltic (Fuji area) and granitic (Tsukuba area) areas is interpreted. It is intended to estimate groundwater residence time based on reaction-flow coupling models. Anthropogenic influence on groundwater quality is discussed, considering the cause for the difference between analytical groundwater data and theoretical model calculations.
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  • Takehiro Ohta, Shuichi Hattori, Yoshihiro Kikuchi
    Session ID: S1-02
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    It was feared that heavy metals and acid water were drained from rock mucks generated by excavating the Hakouda Tunnel of the Tohoku Shinkansen railway because there are some mines around this tunnel. The rock mucks were evaluated about the dissolution features based on geochemical analysis and were disposed to controlled disposal sites if the rock mucks had possibility of heavy metals and/or acid water dissolution. We studied the water-rock interaction at the sites based on the drainage water quality and the geochemical features of rock mucks. It is clear that the ratios of the major ion concentrations are explained by dissolution of pyrite and plagioclase contained in the rock mucks. On the other hand, because the heavy metals are included very little in the drainage water from the disposal sites, it is assumed that these elements are adsorbed to the rock mucks in the disposal site.
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  • Kenji Okazaki, Syuichi Tamoto, Yoshihiko Ito, Takayuki Katoh, Tomoaki ...
    Session ID: S1-03
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The author examined the rate of zeolite and the pH of the eluent relevancy by rock classification, analysis on arsenic, and XRD of the borehole core specimen out of the tunnel ground. As the results, 1) the correlation was admitted in the contaminant content (CC) and the leachate concentration (LC) of the arsenic. Moreover, the type with a lot of LC and the type that LC doesn't exceed criteria value were admitted. 2) As for the pH of the eluent, the CC is a little and the LC is high in 7-9 and neutral-alkalinity. The pH of the eluent is about 8-10 and is alkalinity, and the CC is a little and the LC is high. 3) The negative correlation was admitted in the diffracted intensity of zeolites by XRD and the LC of arsenic.
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  • Koichiro Fujimoto, Tamaki Horike, Masataka Nakata
    Session ID: S1-04
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Gold nanoparticles were produced by ion sputtering and reduction of hydrogen tetrachloroaurate aqueous solution. The color was analyzed by spectrophotometer and Observations by filed emission scanning electron microscope were performed. Comparison with gold particles from ore samples was made. The particle size was changed with color; from violet (globular, 10-15 nm), blue (globular, 10-20 nm), grey (globular with many projections, 120-360 nm), to brown (globular with many projections, larger size). Native gold samples from Hishikari and Akeshi mines, Kagoshima Pref. SW Japan, revealed that they were composed of nanopartilces (100-400 nm), similar to the experimental products.
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  • Yoshiteru Sengen, Koushi Nishimura, Sinji Ohsawa, Takao Hirajima
    Session ID: S1-05
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Marschall et al. (2006) estimated Li/B ratio in greenschists, blueschists, eclogites based on the chemical and modal compositions of main constituent minerals in relevant rocks. These data suggest that Li/B ratio in the hydrated fluid increases from 0.25 to 0.55 with the depths of metamorphic reactions taken place. These data suggest that Li/B ratio becomes a potential tool as an indicator of the generated depth of deep fluids. To verify this idea, we carried out microthermometry and Raman spectroscopy for fluid inclusions in quartz veins/lenses crystallized from 20 to 60 km depths in the Sanbagawa belt, Japan. We further performed Li and B analyses using ICP-MS for extracted fluids from quartz veins/lenses by the crush leaching technique. As a result, although the extracted fluids certainly are the mixture of multi-stages deep fluids, Li/B ratios of them increase with the metamorphic grade of the host rocks from 0.020 to 0.271.
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  • Tatsuhiko Kawamoto, Kenji Mibe, Shigeaki Ono
    Session ID: S1-06
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Subduction zone magmatism is triggered by addition of slab-derived component into overlying mantle wedge. Whether this component is aqueous fluids from dehydration or partial melts of subducting oceanic crust remains an open question. Based on our high-P and high-T radiography experiments at SPring-8, we suggest surprisingly shallow pressures of critical endpoints between aqueous fluids and high-Mg andesite (2.9 GPa, 87 km depth) or sediment (2.5 GPa, 75 km depth). We suggest that slab-derived fluids should be supercritical fluids at the top of subducting slab beneath the volcanic arcs. Under relatively hot conditions, dense liquid-like supercritical fluids are input from dehydrating slab to the overlying mantle wedge. Such dense supercritical fluids produce double magmatism in hot subduction zones by their separation into aqueous fluids and hydrous melts: basalt and sanukite or basalt and adakite.
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  • Eiji Nakata, Hiroshi Suenaga
    Session ID: S1-07
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The pH and groundwater chemistry are expected changing by CO2(aq) dissolution. We organized the field CO2 injection test into Rock mass at Ikeshima coal mine tunnel under the sea bottom S.L.-130m. For the test, 4 drilling holes, which are received holes are prepared by the 7m length to upward at the tunnel roof corner of the 5m square. Additionally, the injection hole are drilled the center of square. The pH, ORP, Fe2+, dD, dO, major chemistry and dCCO2 as tracer are analyze at this injection test.
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  • Yasuko Okuyama
    Session ID: S1-08
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    In CO2 geological storage, the injected CO2 in a long period is expected to be trapped as carbonate minerals and permanently fixed in underground storage system. Geochemical modeling of the storage system, however, derives different results in equilibrium modeling and reactive-transport modeling. The most significant differemce lies in the behavior and quantitative importance of dawsonite, a Na-Al hydrous carbonate. Since the reactive-transport modeling is highly dependent on kinetic parameters, more studies on natural dawsonite are necessary to elucidate the condisions and environments of its formation, thereby deriving kinetic conditions.
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  • Nobuo Hirano, Takuya Ishibashi, Noriaki Watanabe, Noriyoshi Tsuchiya
    Session ID: S1-09
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Accurate prediction of fluid migration within the Earth's crust is required for various engineering applications such as the geologic disposal of high-level nuclear wastes and geothermal reservoirs etc.. Fractures in subsurface rocks behave as major fluid pathways, and identifying fracture flow characteristics is essential. We have been studied fluid flow through single fractures in granite. Showing fluid flow along preferential flow paths due to natural heterogeneity of aperture distributions (channeling flow). The fracture plane is consequently divided into three kinds of areas where flowing, stagnant, and no fluid exists. The fluid flowed area is expected about 10 % of the fracture plane. It is called as 'Flow Wetted Surface' and it is main Water-Rock interaction area.
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  • Takato Takemura
    Session ID: S1-10
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The effect of increasing temperature on the hydro-mechanical properties of rocks is a highly important topic. When we select a site for underground excavation for the disposal of high-level radioactive waste and CO2-underground storage, it is necessary to know the effects of temperature and confining pressure with water, called the deep geological environment. In fact increasing temperatures cause micro-cracking and the production of new clay minerals under long-term immersion in hot water at 90C . It has to be pointed out that the long-term stability of rocks under deep geological environments can be damaged by chemical processes. The chemical weathering in hot water is a time-dependent phenomenon, and it is important to consider hydro-thermal-mechanical properties in rocks under deep geological environments. However, there are few studies of the time and temperature effects on mechanical properties. Additionally, there are only a few studies of sedimentary rocks compared with crystalline rocks.
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  • Hideaki Yasuhara, Naoki Kinoshita, Shinichiro Nakashima, Kiyoshi Kishi ...
    Session ID: S1-11
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    In this work a mechanistic model is presented to describe the compaction behavior of rock fractures mediated by pressure solution and free-face dissolution/precipitation. This model addresses the two distinct, simultaneous dissolution processes at contacting asperities and free walls within fractures. Specifically, a siliceous rock fracture that comprises most dominantly quartz, and a granite fracture composed of quartz, feldspars, and biotite are focused to examine differences of the permeability evolutions attributed to the composed minerals under stressed and hydrothermal conditions. Predictions utilizing the model presented in this study show a relatively good agreement with the experimental measurements for both siliceous and granite rock fractures, although an abrupt reduction observed in the early periods of the experiments is incapable of being replicated.
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  • Kotaro Sekine, Kazuo Hayashi, Kozo Shinoda, Takahisa Shobu
    Session ID: S1-12
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The residual strain in a quartz vein from a metamorphic province is determined by diffraction using synchrotron radiation at beamline BL02B1, SPring-8. Strain scanning method was adapted to measure the distribution of strains parallel to the sample surface. Diffraction angle for unstressed lattice spacing was determined from powder particles of the quartz vein. The peak shape of the quartz vein differs from the powder particles. The peak position shifts to lower diffraction angles and the peak broadening is found. These indicate that not only the macroscopic residual strain is induced in the quartz vein with the platy geometry with respect to the host rock, but also microscopic residual strain is formed across the several quartz grains. The strain magnitude was evaluated by peak shift for {112} reflection. The distribution shows tensile strains of 700 micro strains through the sample with small values near the surface.
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  • Noriyoshi Tsuchiya, Atsushi Okamoto
    Session ID: S1-13
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Several types of mineral filling veins were observed in metamorphic rocks, which provides valuable information on solution chemistry and transport phenomena of geolfuils. Accreational sediments (Shimanto Belt), metamorphics in subduction zone (Sanbagawa metamorphic rocks) and high grade metamorphic rocks in collision zone (Hidaka metamorphic Belts) were investigated. Based on field occurrence, mineral assemblages, mineral texture, and mineral composition of mineral filling vein, formation mechanism of geofluids, especially velocity of fluid ascent through rock fractures, were revealed. Using activity diagram of fluids, small variation of pressure affected stability of potassium feldspar. Ascending flow velocity was estimated on the basis of texture and grain size distribution of quartz within mineral filling vein.
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  • M. Satish-Kumar, J. Hermann, Tomoharu Miyamoto, Yasuhito Osanai, Yoich ...
    Session ID: S1-14
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Elucidating fluid-rock history from a metamorphosed sedimentary rock that has experienced a protracted history in the continental crust is a difficult task. Here we present results of grain to sub-grain scale strontium, oxygen and carbon isotope variations along with LA-ICPMS trace element geochemistry of texturally distinguished carbonates and silicates using cathodoluminescence microscopy, in the granulite grade marble horizons interlayered with metapelitic granulites from two key localities of Skallen and Skallevikshallsen at the Lutzow Holm Bay, East Antarctica. In addition, we have also geochemically characterized some key metamorphic minerals, such as scapolite and apatite, which are sensitive to changing fluid compositions. Such an integrated geochemical approach helped us to reconstruct the multistage metamorphic fluid-rock history preserved in the marble.
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  • Yoshikuni Hiroi, M Satish-Kumar, Daniel Dunkley, Mutsumi Kato, Tatsuro ...
    Session ID: S1-15
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Graphite crystals with growth spirals were first found in an upper granulite-facies sapphirine-spinel-corundum-anorthite-bearing Mg-Al-rich rock from the area to the south of Syowa Station, Antarctica. This finding would be an important clue to the long debated problems about fluids during granulite-facies metamorphism: their absence or presence, behavior, composition, origin and so on. The Mg-Al-rich granulite occurs as a small block enclosed within a dolomitic marble layer. The carbon and oxygen stable isotopic compositions of graphite and coexisting carbonate minerals indicate that they are in equilibrium, and that the fluid from which graphite precipitated was local in origin. The graphite crystals with growth spirals are in direct contact with Mg-cordierite, anorthite, and talc, and probably grew before these minerals as suggested by their textural relations. They probably precipitated from fluid released from partial melts upon cooling after the peak of granulite-facies metamorphism.
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  • Norio Yanagisawa, Munetate Sasaki, Hirofumi Muraoka
    Session ID: S1-P01
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Material and precipitation test was carried out at Otari test field using the fluid of OT-2 well for hot spring ecogene system. Fluid temperature was 70°:C, pH was about 7 with high T-HCO3, Cl and SO4 concentration. In hot spring water path, copper change to chalcopyrite and iron react with CO2. And aragonite, calcite and silica precipitated on heat exchanger. However in cooling water path, aragonite precipitated especially higher temperature area due to super-saturation by heating
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  • Yasumasa Ogawa, Shin-ichi Yamasaki, Noriyoshi Tsuchiya
    Session ID: S1-P02
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Although sequential extractions of heavy metals from soils and sediments have been widely adopted as one of the promising tools for partitioning the different forms of metals in the samples, their applications towards rock samples are rather limited. For establishing this technique for rock samples, we tested the sequential extraction procedure by using powdered and non-powdered (grain size: 2-1mm, 1-0.5mm, 0.5-0.25mm, < 0.25mm) sedimentary rocks to fractionate heavy metals into water, acetic acid and nitric acid extractable fractions, because these reagents are traditionally used for the selective dissolutions for soils and sediments. While alkaline metals were more easily eluted into water from powdered samples as compared with from non-powdered samples, the amounts of eluted heavy metals from the latter were less than those of the former, possibly due to readsorption during the extraction procedure. Certain heavy metals were also dissolved more efficiently from non-powdered sample by acetic acid extraction. The above phenomena caused a considerable change in the obtained fractionation as the decrease of one phase resulted in the increase of another fraction.
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  • Masahiro Kajiwara, Yasumasa Ogawa, Noriyoshi Tsuchiya
    Session ID: S1-P03
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Several rare metals, such as In and Ga, were deposited along the Tamagawa-river originated from the Tamagawa hot spring. As (Arsenic) was adsorbed onto hydrous ferric oxides and precipitated under the condition of low pH (<3.5). However, Ga and In were precipitated under relatively high pH (>3.5) condition. In was more efficiently precipitated than As at Lake Hosen (downstream of Tamagawa-river).
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  • Jinichiro Maeda, Akiko Niino, Toru Yamasaki, Fumiaki Takeda
    Session ID: S1-P04
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Incipient stage of interaction between gabbros and fluids in mid-ocean ridge environments has not been fully described. We found high-temperature metasomatic veins in lower crustal gabbros recovered from 1400-m-long IODP Hole U1309D on the Mid-Atlantic Ridge. Furthermore, we found a tiny grain of native Ni within the metasomatic vein. It is most likely that the metasomatism in the incipient stage of gabbro-fluid interaction was related to CH4-bearing reducing fluids separated from evolved intercumulus or interstitial melts.
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S2: Early differentiation and internal evolution of the Moon
  • Kiyoshi Kuramoto
    Session ID: S2-01
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Redistribution of radiogenic elements likely plays key roles on the long-term thermal evolution of the Moon. Their transport to the lunar shallow layer and deep interior is required for the rapid cooling of lunar lithosphere and for the late heating of lunar interior inducing mare volcanism, respectively. The overturn of unstably stratified cumulate mantle under the Earth's tidal effect may be responsible for the asymmetry in volcanism and radiogenic element distribution between the near side and the far side of the moon.
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  • Noriyuki Namiki, Yoshiaki Ishihara, Sho Sasaki, Seiji Sugita, Shunichi ...
    Session ID: S2-02
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    On the basis of the gravity model of the Moon developed by SELENE (Kaguya), we propose new classification and compensation mechanism of lunar impact basins. Impact basins on lunar far side and limb are classified into Type I and II basins. Most typical mascons are referred as primary mascon basins. Topographic depression and rim of both Type I and II basins show good correlation between topography and free-air gravity anomaly suggesting elastic support of lunar lithosphere. Central gravity high of Type I basin is a result of mantle uplift at the time of basin formation. Free-air anomalies at the center of Type II basins are lower than Bouguer anomalies indicating brittle deformation of the basins.
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  • Yoshiaki ishihara, Sander Goossens, Koji Matsumoto, Hiromoto Noda, Hir ...
    Session ID: S2-03
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    We compute lunar crustal thickness using the latest SELENE gravity and topography data. For gravity, our model is the first model incorporating direct farside tracking by Kaguya/SELENE gravity-mapping mission resulting in an improved gravity field model over the farside. For topography, our model is the first global (including polar regions) topography based on laser altimetry. These data enable us to reduce the truncation and filtering of higher degrees and they allow a more realistic estimation of the lunar crustal thickness variations. Using the newly developed our lunar crustal thickness model, we discuss characteristics of the farside basin structures such as type I and type II basins [Namiki et al., 2009]. We also discuss the causes of the difference between type I and type II basins, that were not discussed by Namiki et al. [2009]. Our model suggests that the differences of type I and type II basins are probably due to difference of the ratio between the pre-impact crustal thickness (Moho depth) and impact scale.
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  • Makiko Ohtake, Yasuhiro Yokota, Junichi Haruyama, Tomokatsu Morota, Ts ...
    Session ID: S2-04
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The multiband imager (MI) is an instrument developed for the SELENE mission. The MI is a high-resolution multiband imaging camera consisting of visible and near-infrared sensors. The spatial resolution of visible bands is 20 m, and that of near infrared bands is 62 m from the 100 km SELENE orbital altitude. In this study we estimated the composition of the lunar crust by analyzing MI data at basin rings, central peaks and crater walls. We first conduct spatial and spectral analyses of 70 locations using MI images so that selected locations are randomly distributed across the moon. We then chose fresh and regolith free (mixing free) areas based on estimates of low degree of optical maturity. The results indicate that extremely feldspathic rocks with nearly 100% crystalline Fe-bearing plagioclase are exposed throughout the lunar highland. The original depth of these extremely feldspathic rocks ranges from 4 to 30 km.
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  • Ryosuke Nakamura, Tsuneo Matsunaga, Group LISM
    Session ID: S2-05
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The South Pole-Aitken basin (SPA) on the Moon is one of the largest impact structures in the Solar System [Spudis et al. 1994]. Although simple scaling predicts complete excavation of the feldspathic upper crust for such a huge impact event [Lucey et al. 1998, Cintala and Grieve 1999], no definite exposure of the underlying mantle has been identified with previous multi-spectral surveys [Lucey et al. 1998, Pieters et al. 1997]. Here we present visible-near-infrared continuous spectra of four distinct crater central peaks inside SPA (Antoniadi, Finsen, Lyman, Bhabha) obtained by Spectral Profiler onboard Japanese lunar explorer Kaguya.
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  • Yuzuru Karouji, Nobuyuki Hasebe, Naoyuki Yamashita, Shingo Kobayashi, ...
    Session ID: S2-06
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The lunar explorer "Kaguay" (SELENE) observed the Moon for 1.5 years and completed its mission. Kaguya Gamma-Ray Spectrometer (KGRS) is an instrument to mearusre the global distribution of elements on the lunar surface by obsering gamma rays emitted from the Moon. Nuclear spectroscopy obtains the element and its concentration related the energy and intensity of gamma ray from the lunar surface. Therefore, a germanium detector with a high energy resolution is adopted as KGRS for the first time in lunar missions. KGRS provides accurate global abundance of the elements on the lunar surface. In this presentation, newly scientific results from KGRS as well as the fundamental principle of gamma ray spectroscopy, observation events of KGRS, and analytical method of KGRS data are reported.
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  • Risa Sakai, Ikuo Kushiro, Hiroko Nagahara, Kazuhito Ozawa, Shogo Tachi ...
    Session ID: S2-07
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Many attempts have been made so far to estimate geophysical and/or geochemical conditions of the lunar magma ocean (LMO). However, there are large disparities in the scale, composition, and cooling history of the LMO. Here we report preliminary experimental results to determine the most plausible compositional range of LMO, which could form the anorthosite (An) crust with satisfying other geophysical and geochemical constraints of the moon as well. We carried out high pressure experiments of An flotation and viscosity measurements for four possible compositions with different FeO contents for LMO. Comparison of densities between plagioclase and melts and calculation results for convection and floatation velocity of An show that the bulk FeO content of LMO was similar to or more than the BSE.
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  • Akira Yamaguchi, Hiroshi Takeda, Yuzuru Karouji, Mitsuru Ebihara, Larr ...
    Session ID: S2-08
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Our understanding of the lunar crust has made considerable progress since the discovery of feldspathic lunar meteorites and global geochemical mapping by lunar missions such as Kaguya. Our detailed mineralogical and geochemical studies show that two lunar meteorites Y86032 and Dho 489 (and paired meteorites) could have come from the regions unsampled by the Apollo missions. Y-86032 is a complicated feldspathic breccia composed of various highland components, and contains unusual Na-rich anorthosite clasts. Dho 489 and paired rocks have bulk compositions with significantly low FeO and high MgO/FeO ratios. The presence of these meteorites indicates that lunar crust is geochemically variable.
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  • Satoshi Tanaka, Yu-ichi Iijima, Hisashi Otake, Jun Kimura, Kiyoshi Kur ...
    Session ID: S2-09
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The next lunar exploration project, &lsquo SELENE-2&rsquo is being planned as a successor to &lsquo KAGUYA &rsquo. SELENE-2. The mission science objectives being updated are categorized into two groups. The first one is related to identification of the Moon-forming material, and the second one is related to clarification of the relationship between surface dichotomy and deeper structure. In this talk, we report the current status and the science scenario of the mission.
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  • Yasunori Miura
    Session ID: S2-10
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Origin of lunar crust is explained as magmatic separation of lunar interior based on terrestrial heat-sources with surface activity. Anorthite-rich crust cannot be identified on Martian surface compared with similar the Moon (ca.4.6Ga older), though the oldest terrestrial rocks are changed less than ca.4.0 Ga. Carbon-bearing materials are found to be remained in rocks during impact events observed in Lunar, Martian and terrestrial rocks found in explosion, breccias and meteorites in this study. Due to effects by carbon-bearing materials, magmatic separation in the lunar crust can be explained by fluidal activity of cool carbon dioxides to produce various rocks and volcanic glasses. In short, it is found in this study that lunar crust components with carbon are stored from primordial Earth during giant-impact, and buried carbon dioxides fluid is considered to produce crustal separation and evolution for present lunar crust.
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R1: Magma process and subduction factory
  • Tomoaki Morishita, Yildirim Dilek, Minella Shallo, Akihiro Tamura, Sho ...
    Session ID: R1-01
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    We report petrological and mineralogical characteristics of the uppermost mantle section of the Eastern belt of the Mirdita ophiolite, Albania, in the context of maturing of the island arcs.
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  • Tsukasa Ohba, Kazuhide Matsuoka, Yasuyuki Kimura, Hiromasa Ishikawa, H ...
    Session ID: R1-02
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The depth of crystallization differentiation was investigated for tholeiite basalts from Hakkoda and Hachimantai. Olivine-hosted melt inclusions contain aluminous clinopyroxene, spinel, plagioclase, and rare garnet, suggesting melt-entrapment under garnet-granulite facies conditions. Removal of the observed phenocrysts cannot account for the chemical variations, although the variations are typical of a tholeiitic differentiation trend. The trace element modelling indicates fractionation of cpx, pl, and spinel. The assemblage is consistent with that in the melt inclusions except for garnet. Fractional crystallization modelling closely approximates the major element variations at 10 kbar under anhydrous conditions. The modelling is consistent both with the melt-inclusion mineralogy and with the trace element modelling. An estimated depth of crystallization of 34 km (10 kbar) corresponds to the seismic Moho in the region (35-36 km). Our data also suggest that the relatively anhydrous magmas that were emplaced at Moho depths became hydrous concurrent with differentiation, implying incorporation of water from the surrounding crustal rocks.
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  • Masao Ban, Shiho Hirotani, Mitsuhiro Nakagawa
    Session ID: R1-03
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Detailed petrologic study revealed the rocks of Shirataka volcano were formed by two end-members mixing. The mafic end-members were mainly medium-K basalts, but in the beginning of the activity they were low-K ones. The low-K basalt is inconsistent with the systematic across-arc variation, because Shirataka volcano is situated in back arc side. The degrees of partial melting of mantle in producing the low- and medium-K basalts had been fixed, because the HFSE abundances of these two are similar. In contrast, Rb as well as K abundance is obviously higher in the medium-K than low-K, which suggests different effects of subduction-derived fluids to their compositions. If the medium-K mafic magmas were derived from the up-welling hydrous mantle, which was newly metasomatized, then the low-K ones would be generated from yet metasomatized mantle surrounding the up-welling.
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  • Osamu Ujike
    Session ID: R1-04
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Strontium content of plagioclase in volcanic rocks from Hakusan were determined using EPMA techniques. Interiors of dusty zone of phenocrysts are constantly poor in Sr (<0.20 wt. % SrO), while the Sr content outside the zone is rather high (up to 0.40 wt. %). Results of calculation using partition coefficients of Sr suggests that the interiors coexisted with felsic melts with <400 ppm Sr, while the exteriors crystallized from mafic melts varyingly rich in Sr up to 1200 ppm.
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  • Satoshi Saito, Makoto Arima, Takashi Nakajima
    Session ID: R1-05
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Miocene granitic plutons such as Tanzawa, Kofu and Kaikomagatake are widely exposed in the Izu Collision Zone. We examine petrographical, geochemical and Sr-isotopic characteristics of the Kaikomagatake pluton exposed in northwestern part of the collision zone and discuss its petrogenesis. We conclude that Kaikomagatake pluton evolved by crystal fractionation process from primary magma (SiO2=∼68wt%) and the primary magma were formed by anatexis of the K-rich source compositionally similar to the rocks occurring in the back arc side of the Izu-Bonin arc.
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  • Yoshihiko Tamura
    Session ID: R1-06
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    The Izu-Bonin-Mariana (IBM) arc is currently active, but this 50-million-year-old subduction-zone system contains Oligocene middle and lower crust below the upper crust, that is in turn covered by Quaternary volcanic rocks. However, remnants of this old crust segments have never been found at the northern end of the Izu-Bonin arc, where it is colliding with the Honshu arc. Two large plutons in the collision zone (the Tanzawa tonalites (and their syn-plutonic dikes) and the Kofu Granitic Complex) were emplaced in the Miocene (4-17 Ma). We show here that major elements, trace element ratios of Zr/Y, and REE patterns indicate that the Kofu Granitic Complex and Tanzawa tonalites (and their syn-plutonic dikes) are more akin to the Oligocene IBM volcanic rocks, and that they are dissimilar to the Neogene and Quaternary Izu-Bonin magmas. One possibility is that Miocene plutonic rocks in the Izu collision zone were derived from the Oligocene middle crust.
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  • Sho Yatsuka, Satoshi Okamura, Toyoto Azuma, Izumi Sakamoto, Yong Ui Ki ...
    Session ID: R1-07
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    MORB-like basalts have been dredged from the trench side slope of the Bonin Ridge and the Hahajima Seamount, the Izu-Bonin fore-arc. They are characterized by high TiO2 contents compare to island arc tholeiites. MORB-like basalt from the trench side slope of the Bonin Ridge has low Zr/Nb ratio similar to E-MORB rather than N-MORB. On the other hand, MORB-like basalts from the Hahajima Seamount have high Zr/Nb ratio similar to N-MORB and their compositions are similar to Pacific MORB.
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  • Yushi Takada, Kazuhito Ozawa
    Session ID: R1-P01
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Homogeneous differentiation involving separation of crystals nucleated and grown in the main magma body of a crustal magma chamber and boundary layer fractionation involving compositional convection induced by crystal growth in the cooler marginal zone are thought to be the major differentiation mechanisms (Jaupart and Tait, 1995; Marsh, 1996). These contrasting differentiation mechanisms are linked to mechanisms of heat transfer: thermal convection and heat conduction, respectively, showing strong coupling between material and thermal transfer in a magma chamber. There is, however, no consensus about which mechanism is actually operated and its controlling factors determining the fate of magma chamber. This issue can be addressed by combining theoretical modeling and observation on a geometrically simple sheet-like intrusion, which records temporal change of the physical and chemical conditions of the magma system as sequential changes of composition and microstructure from the chilled margins to the last frozen zone.
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  • Ushio Honma, Hiroaki Sato
    Session ID: R1-P02
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    We examined the effect of water on the stability and Ca-Na partition relation between plagioclase and melt in a within-plate alkali basalt (type-1) and an arc tholeiite (type-2) from Oginosen volcano, southwest Japan. Compared with the previous experimental results, the present experimental results gave smaller effects of water on the Ca-Na partition coefficients.
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  • Murata Mamoru, Nozomi Nitta, kyoko Tani, Hiroaki Ozawa, Hiroshi Nishim ...
    Session ID: R1-P03
    Published: 2009
    Released: April 06, 2010
    CONFERENCE PROCEEDINGS FREE ACCESS
    Shimo-ondori adakitic granitoids intrude discordantly into the lower Cretaceous Akamatsu Formation, northern Shimanto Supergroup, Naga, Tokushima, outer zone of Southwest Japan. The granitoids consist of five small masses (5m x 15m) which were sporadically distributed. They were named A, B, C, D and E masses from east to west. The rocks, which contain mainly of hornblende and plagioclase, show wide chemical variation from high Mg andesite to adakite, but the minerals show restricted chemistries; mg values of hornblende range 0.65 to 0.81, those of salite, remnant in hornblende, range 0.75 to 0.82,and plagioclase shows albite composition. Three samples from B mass and one sample from E mass were selected for hornblende K-Ar age determination. 100 to 150 mesh size fraction from B-1 and 100 to 200 mesh fractions from B-3, B-5 and E-2 were determined at Hiruzen Institute for Geology and Chronology. The hornblende K-Ar ages from B mass yield 112.7+/-5.7, 129.6+/-6.4 and 131.4+/-6.6Ma, and the age from E-mass yields 94.3+/-4.7Ma. The result is too old to be the heat source for 14Ma granitoids in the outer zone of Southwest Japan.
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R2: Plutonic and metamorphic rocks
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