著者

榎並 正樹

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.35, no.1, pp.11-21, 2006 (Released:2006-03-01)

参考文献数

26

被引用文献数

5 9

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Asbestos consists of fibrous aggregates of serpentines and/or amphiboles including chrysotile, anthophyllite-gedrite, cummingtonite-grunerite, tremolite-actinolite and riebeckite. The dispersion staining method, X-ray diffractometry, electron-probe microanalysis and Raman spectroscopy are briefly reviewed to assess their potential use for asbestos identification. Optical, crystal chemical and spectrographic characteristics of asbestos are summarized along with their powder X-ray diffraction patterns, energy dispersive spectra and Raman spectra data.

著者

新井 宏嘉 宮下 敦 田辺 克幸 村田 守

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.40, no.6, pp.177-194, 2011 (Released:2012-01-21)

参考文献数

57

被引用文献数

5 7

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Jadeite-bearing meta-basalt occur within a greenstone complex at the southern margin of the Mikabu greenstones in the Shimonita area, northern Kanto Mountains, Central Japan. The greenstone complex shows a block-in-matrix structure consisting of small, sporadically occurring greenstone blocks (jadeite-bearing meta-basaltic lavas, jadeite-free pargasite rocks, and jadeite-free garnet-epidote rocks) embedded within a matrix of actinolite rocks. The complex has been interpreted as a tectonic mélange composed of allochthonous metamorphic blocks within the Mikabu greenstones. However, both the greenstone blocks and actinolite rocks preserve original igneous or pyroclastic textures without the deformation structures commonly seen in tectonic mélanges. The concentrations of high field strength (HFS) elements within the jadeite-bearing lavas indicate that these rocks are alkali basalts derived from oceanic island basalt (OIB). The composition of these lavas is similar to that of OIB blocks in the Mikabu greenstones in Shikoku, western Japan. The whole-rock chemical composition of the lavas reveals higher Na2O concentrations (max. 10.1 wt%) than in unmetamorphosed Hawaiian OIB alkali basalts. The actinolite rocks of the matrix show a pyroclastic texture and contain relic Ca-pyroxenes. The concentrations of HFS elements and pyroxene chemistry of the actinolite rocks indicate an origin from tholeiitic MORB, similar in composition to typical Mikabu greenstones in the Kanto Mountains and Shikoku. These observations strongly suggest that the greenstone complex is not a tectonic mélange comprising allochthonous metamorphic rocks within a matrix of Mikabu greenstones, but that the entire complex consists of Mikabu greenstones. Therefore, the complex was subjected to Sanbagawa metamorphism after a Na-enrichment event; jadeite grew in Na-rich blocks during the metamorphism.

著者

新田 恵理子 木股 三善 星野 美保子 越後 拓也 濱崎 聡志 篠原 宏志 西田 憲正 八田 珠郎 清水 雅浩

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.35, no.6, pp.270-281, 2006 (Released:2007-03-15)

参考文献数

43

被引用文献数

1

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High temperature volcanic sublimates including so-called “molybdenum blue” sampled around the high-temperature fumaroles at Iwodake volcano, Satsuma-Iwojima, Kyushu, Southwestern Japan, were characterized by X-ray powder diffraction, X-ray micro-diffraction, Raman micro-scattering, electron microprobe and X-ray photoelectron spectroscopic analyses. The identified minerals are molybdenite, sphalerite, tugarinovite, molybdite, hematite, halite, sylvite, anglesite, wulfenite, quartz, tridymite, cristbalite and potassium alum. Occurrences of both tugarinovite and molybdite are observed in Kudriavy volcano, too, and the coexistence of their minerals is characteristic of high-temperature volcanic sublimates. The molybdenite and sphalerite from Iwodake are exceedingly rich in Re (up to 0.77 wt%) and In (up to 1.69 wt%), respectively, distinguished from those of a different origin by chemical composition. The molybdenite consists of both of 3R and 2H1 polytypes. Sublimates from Iwodake and Kudriavy volcanoes are similar in mineralogy. Although the difference in the host rock arises between the Iwodake (rhyolite) and the Kudriavy (basaltic andesite) volcanoes, their volcanic gases resemble each other in F and Cl contents. This resemblance might cause the similarity in sublimate mineralogy between these volcanoes.

著者

田切 美智雄 松本 哲平 谷本 一樹

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.32, no.4, pp.175-184, 2003 (Released:2008-04-21)

参考文献数

11

被引用文献数

2 4

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Precision of the degree of graphitization (GD) is evaluated based on repeated experiments on a sample of pelitic schist, and analyses on ten pelitic schists collected from an outcrop. The experimental error is ±2 in two sigma confidential level at GD=31 and GD=26, respectively. The results suggest that if GD value difference is larger than 6, two neighboring samples have the discontinuous metamorphic grade. The systematic sampling and experiments along the direction normal to the strike, revealed the discontinuous boundaries of the metamorphic grade existing at a upper stream of the Sanbagawa-river and at an outcrop of the Arakawa-river, i.e., the boundaries between the shuffled cards Miyashiro (1994). The former boundary is serpentinitic greenschist within the pelitic schists, the latter one, the thrust plane in pelitic schists. A thick layer having continuous GD value also exists in the Sanbagawa metamorphic terrain as revealed by the experiments of the Kamabuse-yama boring core of 280m depths.

著者

渡邊 新六

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石礦物礦床學 (ISSN:18830757)

巻号頁・発行日

vol.17, no.3, pp.145-150, 1937-03-01 (Released:2008-03-18)

参考文献数

3

著者

奥村 聡

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.52, no.1, pp.230724, 2023 (Released:2023-09-26)

参考文献数

17

---

Magma rheology is a key factor in understanding and modelling volcanic eruptions. Until now, macroscopic rheology experiments reveal the viscosity of the magma and conditions at which shear thinning and brittle failure occur. However, it remains unclear what mechanisms control complex magma rheology from the atomic and molecular-scale structure perspective. More specifically, no experimental data on molecular-scale structure have been obtained for deforming magma in the non-Newtonian regime. To resolve this situation, we have developed an experimental system for time-resolved X-ray diffraction and scattering at SPring-8, Japan. Based on the experiments on this system, we found that intermediate-range ordering (IRO), which is related to the size of the ring formed by SiO4 tetrahedra, expands under tensional deformation. In particular, the IRO shows elastic and anisotropic deformation in the non-Newtonian regime. On the other hand, the short-range ordering such as T-O and T-T distances, where T and O represent Si and Al in the T-site and oxygen, respectively, shows no clear change during the deformation. These results imply that shear thinning and brittle failure may originate from the expansion of the ring size because the large ring is relatively weak and its formation results in cavitation. According to this model, the magma fails when the stress is large enough, rather than the strain rate, because the IRO deforms according to the stress applied to the structure. Recent experiments also observed that small and anisotropic rings form under compression. Previous rheology experiments did not confirm the difference between the conditions, at which shear thinning and brittle failure occur, under tension and compression, but the experimentally-determined molecular-scale structure clearly shows different behavior. To fully understand the mechanism of magma rheology from the view of the molecular-scale structure, we need to perform additional studies including the experiments and theoretical approaches.

著者

富岡 尚敬

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

pp.231002, (Released:2023-10-16)

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Akimotoite (IMA1997-044), (Mg,Fe)SiO3, a new silicate mineral of the ilmenite group, has been discovered in the shocked Tenham chondritic meteorite. It occurs as aggregates adjacent to clinoenstatite in host-rock fragments trapped into shock-induced melt veins. Chemical analysis gives the simplified formula to be (Mg0.79Fe0.21)SiO3, the same as for clinoenstatite. Selected-area electron diffraction (SAED) patterns correspond to the synthetic (Mg,Fe)SiO3 ilmenite phase with the space group R3. The lattice parameters estimated from the SAED patterns are a = 0.478(5) nm, c = 1.36(1) nm in the hexagonal setting. The calculated density is 4.0(1) g/cm3. In a shock-induced melt vein, akimotoite and clinoenstatite are intergrown with a topotaxial relationship in which close-packed oxygen layers of both phases are preserved. This occurrence suggests that the enstatite-akimotoite transition was caused by a shear transformation mechanism without long-range atomic diffusion.

著者

佐々木 宗建 徂徠 正夫 奥山 康子 村岡 洋文

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.38, no.5, pp.175-197, 2009 (Released:2009-11-26)

参考文献数

48

被引用文献数

2 2

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Water qualities and occurrence of precipitates in 10 hot and mineral springs with large calcareous deposits in Japan were investigated in order to elucidate geochemical conditions of the precipitation of carbonate minerals and water-rock interactions in their reservoirs. Chemical analyses of water samples have revealed that the spring waters were rich in NaHCO3 and CO2 components. Out of 10 springs investigated, 2 springs contain Ca and CO2-related soluble components with genetic relations to the dissolution of limestone underground; 4 springs also enriched in Ca were green-tuff type affected by gypsum dissolution. Other springs poor in SO4 component have geochemical characteristics suggesting the contribution of deep-seated fluid. The pH of reservoir fluids is considered to be buffered by CO2-HCO3 speciation. This chemical condition probably promotes rock alteration including dissolution of calcite and plagioclase, resulting in formation of large calcareous deposits in the fields studied. The calcareous precipitates consist only of calcite in three fields with relatively low water temperatures; the other deposits contain aragonite with calcite possible due to their formation at high temperatures and high concentrations of Mg, Mn and SO4 in spring waters. From a comparison of water chemistry at the points of precipitation, logarithmic critical saturation indices (SI) are empirically derived to be 0.7-0.9 for calcium carbonate and over 3.5, 0.5, 1.2 and 3.4 for dolomite, magnesite, siderite and dawsonite, respectively. Distribution coefficients of Sr and Mg between spring water and precipitates indicate that calcareous precipitates were formed near equilibrium conditions.   The possible ware-rock interaction processes elucidated in this study should be taken into account for geochemical modeling of CO2 geological reservoirs. The empirical values of SI, which are all positive for major carbonate minerals, can be the most important finding because geochemical simulation previously conducted commonly assumed precipitation at the point of saturation (SI=0).

著者

奥村 聡

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

pp.230724, (Released:2023-09-07)

---

Magma rheology is a key factor in understanding and modelling volcanic eruptions. Until now, macroscopic rheology experiments reveal the viscosity of the magma and conditions at which shear thinning and brittle failure occur. However, it remains unclear what mechanisms control complex magma rheology from the atomic and molecular-scale structure perspective. More specifically, no experimental data on molecular-scale structure have been obtained for deforming magma in the non-Newtonian regime. To resolve this situation, we have developed an experimental system for time-resolved X-ray diffraction and scattering at SPring-8, Japan. Based on the experiments on this system, we found that intermediate-range ordering (IRO), which is related to the size of the ring formed by SiO4 tetrahedra, expands under tensional deformation. In particular, the IRO shows elastic and anisotropic deformation in the non-Newtonian regime. On the other hand, the short-range ordering such as T-O and T-T distances, where T and O represent Si and Al in the T-site and oxygen, respectively, shows no clear change during the deformation. These results imply that shear thinning and brittle failure may originate from the expansion of the ring size because the large ring is relatively weak and its formation results in cavitation. According to this model, the magma fails when the stress is large enough, rather than the strain rate, because the IRO deforms according to the stress applied to the structure. Recent experiments also observed that small and anisotropic rings form under compression. Previous rheology experiments did not confirm the difference between the conditions, at which shear thinning and brittle failure occur, under tension and compression, but the experimentally-determined molecular-scale structure clearly shows different behavior. To fully understand the mechanism of magma rheology from the view of the molecular-scale structure, we need to perform additional studies including the experiments and theoretical approaches.

著者

秋澤 紀克

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.52, no.1, pp.230204, 2023 (Released:2023-06-17)

参考文献数

84

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The life cycle of the oceanic lithosphere commences in the spreading axis and ends in the subduction zone. To trace the cooling and evolutional history of the Earth, the change in thermochemical state during the life cycle of present‒day oceanic lithosphere is desired to be elucidated. In terms of the material science, spatial limitation of human‒accessible Earth interior is a bottleneck in reconstructing the thermochemical state of the oceanic lithosphere. Yet, by combining active sampling methods using ocean research vessels (ocean drilling, ocean bottom dredging, submersible survey, etc.) and passive sampling methods using Earth’s deep materials exposed to the surface owing to tectonic forces and volcanoes, we can collect samples that cover a considerable dimension. Here, I present efforts toward the elucidation of the thermochemical state of the oceanic lithosphere during its life cycle from the spreading axis to the subduction zone. The Oman ophiolite is presented as an analogue of oceanic lithosphere formed in the vicinity of a fast‒spreading axis, whereas the peridotite xenoliths from Tahiti Island are treated as an analogue of thermochemically disturbed oceanic lithosphere by a mantle plume, and those from petit‒spots are considered as an analogue less affected by thermochemical disturbance considering the lack of mantle plume beneath the petit‒spots. A heterogeneous thermal state corresponding to the segment structure is inferred in the fast‒spreading axis. The thermochemical state of the aging oceanic lithosphere is modified by mantle plume and petit‒spot magmatism, but pristine state can be reconstructed by using suitable peridotite xenoliths whose heating‒cooling and melting history is well characterized. The peridotite xenoliths from the petit‒spots can enhance a step toward reconstructing the thermochemical state of the deep oceanic lithosphere because deep‒rooted garnet‒stable peridotite xenoliths can be found.

著者

越後 拓也

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.47, no.1, pp.34-42, 2018 (Released:2018-03-21)

参考文献数

56

---

Organic minerals are natural organic compounds with both well-defined chemical composition and crystallographic properties; their occurrences show traces of the high concentration of certain organic compounds in natural environments. Thus the origin and formation process of organic minerals will lead us to understand the fate and behavior of the organic molecules in the lithosphere. All of each organic mineral can be classified into the one of following two groups: ionic organic minerals in which organic anions and various cations are held together by ionic bonds, and molecular organic minerals in which electroneutral organic molecules are bonded by weak intermolecular interactions. Karpatite, a natural crystal of coronene (C24H12), is the most typical molecular organic minerals and its crystal/molecular structures and carbon isotopic composition suggests that this mineral was crystallized from PAHs (polycyclic aromatic hydrocarbons)-rich hydrothermal petroleum by hydrothermal activity. In the process of formation of organic minerals, the formation of structural units, such as organic acid anion and PAH molecules, precedes their migration and concentration. The first stage includes the formation or cleavage of C-C bonds, but the latter stage does not. In addition, we have investigated the influence of size, morphology, surface structure, and aggregation state on the reductive dissolution of hematite with ascorbic acid using two types of nanoparticles with average diameters of 6.8 ± 0.8 nm and 30.5 ± 3.5 nm, referred to as Hem-7 and Hem-30, respectively, in this paper. TEM (transmission electron microscope) observation revealed that previous to dissolution, Hem-7 is present as both dispersed particles and as aggregates. Dispersed particles dissolve initially before aggregates, which influences its dissolution rate. The Hem-30 hematite has nanoscale surface steps and internal defects, and its dissolution initiates from the steps, defects, or sharp edges of the crystals. This study directly shows the importance of size, surface roughness, defects, crystal morphology and aggregation states on dissolution rates of nanoparticles.

著者

川嵜 智佑

出版者

一般社団法人 日本鉱物科学会

雑誌

日本岩石鉱物鉱床学会 学術講演会 講演要旨集 2005年 日本岩石鉱物鉱床学会 学術講演会

巻号頁・発行日

pp.43, 2005 (Released:2008-04-04)

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泥岩の溶融実験からコランダム-石英共生を得たので、報告する

著者

牧野 州明 山口 佳昭 冨田 克敏

出版者

一般社団法人 日本鉱物科学会

雑誌

岩鉱 (ISSN:09149783)

巻号頁・発行日

vol.91, no.11, pp.419-423, 1996 (Released:2006-10-28)

参考文献数

16

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Fluor edenfite was found in cavities of the Ishigamiyama lava dome building two pyroxene-hornblende-andesite in the Kimpo volcano, Kumamoto, southwest Japan. The fluor edenfite is associated with tridymites and magnetites in the cavities. This is the first description of volcanic fluor-amphibole, and its chemical analysis was made by combining microprobe, vacuum-heating method and Mössbauer spectroscopy. The Ishigamiyama fluor edenite has 1.47F, 0.13OH, 0.03Cl and 0.37O pfu in the O3 site, and thus, is characteristically poor in (OH). This edenite is the most F-rich one in edenites and edenitic hornblendes previously reported.

著者

木下 龜城

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.25, no.1, pp.29-36, 1941-01-01 (Released:2008-03-18)

参考文献数

5

著者

佐藤 満雄

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.30, no.6, pp.288-299, 2001 (Released:2008-08-30)

参考文献数

21

被引用文献数

1 1

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Framework structures of tectosilicates including zeolite, silica and feldspar minerals are reviewed on the basis of concentric cluster (CCL). The structural characteristics of them can be simply represented by the points (Si or Al atoms) and the lines connecting between the points. Starting from a given point, an nth CCL can be graphically defined as a set of all the points ranging from topological distance 0 to n, and all the lines responsible for the connection between them. The topological distance used here means the shortest step numbers responsible for the connection between two points, not the geometrical distance. As any kind of tectosilicate frameworks can be completely covered with the CCL by extending its topological distance from 0 to n, the topological characteristics of them are realized on a series of these CCLs. In order to quantify these CCLs, the front nodes are newly defined, and a concept of the coordination degree sequence (CDS) is introduced. In the CDS, the front nodes are characterized in terms of their topological valence numbers. The CDS can be effectively applied to the topological characterization, the classification, and the systematic computer modeling of tectoslicate frameworks. Some of application examples are shown.

著者

吉木 文平

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.1, no.4, pp.188-200, 1953-10-10 (Released:2010-02-08)

参考文献数

26

著者

真崎 克彦 上原 誠一郎

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.20, no.1-2, pp.33-42, 1991-05-01 (Released:2009-08-11)

参考文献数

35

被引用文献数

1 1

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Weathering products in a brown soil (sample S3) and in a partially weathered antigorite in yellowish brown color (sample A59b) were collected from the serpentinite zone in Sasaguri area, Fukuoka Prefecture, Japan. The products were studied by X-ray diffraction, transmission electron microscopy, analytical electron microscopy, infrared absorption spectrumand differential thermal analysis. Mineralogical composition of the brown soil are 14Å intergrade, halloysite, goethite and ferrihydrite associated with Si, and hematite. Si-containing goethite, Si-containing ferrihydrite, hematite and hisingerite were found in the weathered antigorite. The results suggest that leaching of Mg and Si from the serpentine minerals occurred at initial weathering stages. Precipitation of hydrous iron oxides and hydrous iron silicates may occur after the leaching of Mg and Si. Poorly crystallized iron minerals showed aggregate of microcrystalline materials (<100Å). The result suggests that the 14Å intergrade and halloysite were produced from weathered chlorite and/or mica minerals in the crystalline schist, or weathered chlorite in the vein at the serpentinite zone, or 2 : 1 layer silicates in eolian dust.

著者

武田 弘

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.12, no.2, pp.89-102, 1975-01-31 (Released:2009-08-11)

参考文献数

17

被引用文献数

5 4

著者

下平 高次郎 広島 勉

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.14, no.Special2, pp.96-108, 1980-03-10 (Released:2009-08-11)

参考文献数

11

被引用文献数

1 1

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The Synthesis of Opalin Materials Takajiro Shimohira, Tsutomu Hiroshima: National Institute for Researches in Inorganic Materials, Sakura-mura, Niiharigun, Ibaraki Opalin materials which show some of the characteristics of natural precious opal have been synthesized. The process of making the materials was as follows;1) Monodispersed suspensions of spherical silica particles of colloidal size were produced by means of hydrolysis of ethyl silicate.2) An ordered close-packed array of hydrated silica particles has been achieved by sedimentation over a period of several months.3) Sintering and impregnation method were used to harden the arrays of stacked spheres.

著者

長瀬 敏郎 石川 志緒利 栗林 貴弘

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.47, no.3, pp.127-140, 2018 (Released:2018-11-17)

参考文献数

56

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Nishiki-ishi is a kind of jasper and shows mixed bright red, yellow-brown, green, and black colors. It occurs in Tsugaru region, Aomori Prefecture Japan and has been used for ornaments. Most of the raw stones are usually collected at shingle beaches, and few outcrops of the jasper are found out. Therefore, the occurrence of Nishiki-ishi has not been reported in detail. To elucidate the formation process of Nishiki-ishi, we observed textures of the rocks and minerals by optical and electron microscopes, Raman spectroscopy and analyzed the chemical compositions of minerals by an electron micro-probe analyzer. Nishiki-ishi were collected from two localities: Aoiwa, Nakadomari-machi, Kita-Tsugaru and Tappi-zaki, Sotogahama, Higashi-Tsugaru, Aomori Prefecture, Japan. It mainly consists of mixtures of micro-crystalline and crypto-crystalline quartz, opal-CT and iron-containing minerals. Its colors are caused by iron-containing minerals; hematite (red), celadonite (green), goethite (yellow), siderite (yellow), pyrite (black), and marcasite (black). These iron-containing minerals, which exhibit needle-like or granular forms, are included as fine grains in quartz crystal and fill boundaries among the quartz crystals. The macroscopic structure of Nishiki-ishi is breccia-like or clastic. In the texture, breccia fragments show yellow or red colors, and green and black parts filled up the space between breccia fragments. Yellow-brown and red color parts of Nishiki-ishi have flamboyant and mosaic (jigsaw) textures, which consist of micro-quartz and optically length-slow type spherules of quartz. Black and green color parts are also composed of opal-CT, chalcedony, and micro-quartz. These features are considerable differences of quartz textures between in brecciated fragments and at the matrix among brecciated fragments. Nishiki-ishi was formed by silicification of volcanic rocks during volcanic activity. After the silicified rocks brecciated, quartz and chalcedony precipitated in the breccia.