著者

Yohey SUZUKI Takeshi SUKO

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.101, no.6, pp.299-307, 2006 (Released:2007-01-08)

参考文献数

79

被引用文献数

43 53

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Understanding the behavior of uranium (U) in the environment is essential not only for the protection of aquifers from U contamination but also for predicting the fate of U and other actinides disposed of in deep geological settings. It has long been believed that the redox chemistry of U can be simply predicted by thermodynamics and that the development of a low redox potential is a sufficient condition for U reduction. However, recent studies have demonstrated that redox transformations of U are controlled by kinetic factors that are strongly influenced by microbial activity. Although abiological U oxidation proceeds efficiently under oxygenic conditions, abiological reduction of U is inhibited by the formation of negatively charged U(VI)-CO3 complexes that prevail in nature. Phylogenetically diverse microorganisms are capable of enzymatically reducing U(VI)-CO3 complexes to form U(IV)-bearing minerals such as uraninite (UO2+x). The only abiological pathway currently known for the reduction of U(VI)-CO3 complexes involves the Fe(II) monohydroxo surface complex ≡FeIIIOFeIIOH0. This complex is mainly produced by the microbial reduction of Fe(III) in natural systems. Thus, U(VI) reduction is controlled both directly and indirectly, at least in part, by microbial activity. Several mechanisms of U oxidation under anoxic conditions have been revealed recently by laboratory and field studies. U(IV) is abiologically oxidized by Fe(III) and Mn(IV) oxides. Microbial reduction of nitrate to molecular nitrogen, which occurs following the depletion of O2, produces nitrogen intermediates including nitrite (NO2−), nitrous oxide (NO), and nitric oxide (N2O). Although the nitrogen intermediates oxidize U(IV), poorly crystalline Fe(III)-oxide minerals resulting from the oxidation of aqueous Fe(II) species by the nitrogen intermediates oxidize U(IV) more efficiently than the nitrogen intermediates alone. Remarkably, the formation of Ca-U(VI)-CO3 complexes resulting from increased levels of Ca2+ and/or HCO3− leads to the reoxidation of bioreduced U(IV) under reducing conditions. These geomicrobiological factors pose challenges in manipulating and/or predicting the mobility and fate of U in complex and heterogeneous environmental settings.

著者

Ernest H. NICKEL

出版者

Japan Association of Mineralogical Sciences

雑誌

Mineralogical Journal (ISSN:05442540)

巻号頁・発行日

vol.17, no.7, pp.346-349, 1995 (Released:2007-03-31)

被引用文献数

5 6

著者

Tohru OZAWA Akihiro SAITOW Hidemichi HORI

出版者

Japan Association of Mineralogical Sciences

雑誌

Mineralogical Journal (ISSN:05442540)

巻号頁・発行日

vol.20, no.4, pp.179-187, 1998 (Released:2007-03-31)

参考文献数

14

被引用文献数

1 1

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Giessenite was reported as an acicular crystal that shared a close association with Sb-bearing cosalite from the Otome mine, Yamanashi Prefecture (Ozawa and Hori, 1982). Recent criteria classify it as izoklakeite.The Otome izoklakeite, which is orthorhombic (Pnnm or Pnn2 from its orthogonal lattice and systematic extinction, in agreement with previous reports), has unit-cell dimensions of a 34.067, b 38.085, c 4.056Å. In addition, diffuse reflections which double the periodicity of 4.056Å along the c-axis are observed, also in agreement with the report on Vena izoklakeite (Zakrzewski and Makovicky, 1986).An electron microprobe analysis gives Cu 0.8, Fe 0.3, Ag 1.1, Pb 46.5, Bi 27.2, Sb 7.3, S 16.2, total 99.4wt.%, yielding the empirical formula (Cu2.7Fe1.2)3.9Ag2.2Pb48.7(Bi28.2Sb13.0)41.2S109.7, assuming the total cation=96 in a unit cell. It has a Sb/(Sb+Bi) value of 0.316, and is the most Bi-rich of the known izoklakeites.

著者

Geoffrey H. GRANTHAM M. SATISH-KUMAR Kenji HORIE Henriette UECKERMANN H

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.230125, (Released:2023-05-16)

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The ~550 Ma Kuunga Orogeny extends from the Damara in Namibia, through the Zambesi and Lurio orogenic belts in Zambia and Mozambique, southern Africa, through Dronning Maud Land and Princess Elizabeth Land, Antarctica into western Australia. Sverdrupfjella is located at the western end of Dronning Maud Land where the Kuunga Orogeny is inferred to post-date and overprint the East African Orogeny.Three complexes are recognized in Sverdrupfjella western Dronning Maud Land , Antarctica. A western basal ~1140 Ma Jutulrora Complex, consisting mostly of arc-related tonalitic trondjhemitic orthogneiss with evolved Sr - Nd isotopic signatures with TDm ages >2 Ga. It is structurally overlain by the Fuglefjellet Complex, comprising supracrustal ~800 – 900 Ma carbonates intercalated with quartzo-feldspathic gneisses with detrital zircons of ~1000 - 1200 Ma age with ~500 Ma overgrowths. The Fuglefjellet Complex is overlain in the east by the Rootshorga Complex containing paragneisses with minor orthogneisses (~1100 – 1200 Ma), intruded by granitic orthogneiss of similar age. Strontium - Nd isotopic signatures from the Rootshorga Complex has TDm ages <1.8 Ga.D1 and D2 planar fabrics typically dip to SE with vergence top-to-NW in all complexes. D3 deformation verges top-to-the-SE. In the Jutulrora Complex, D3 comprises ~100m scale folds with NW dipping axial planes, cut by SE dipping dilational granite sheets. In the Rootshorga Complex D3 is characterised by syntectonic granite veins with extensional and compressional displacements with top-to-the SE shear. Discordancies are consistent with low angle thrust planes at Fuglefjellet and Kvikjolen with probable repetition of carbonate layers.Zircon ages of the granitic sheets are 490 - 500Ma. Strontium and Nd isotopic signatures of the granitic sheets intruded into all complexes are consistent with melting of Jutulrora Complex crust with Archaean and Mesoproterozoic xenocrysts in some samples. Top-to-SE shear zones displace pegmatites with an inferred age of 520 Ma and are syntectonic with layer parallel ~490 Ma granite sheets.P-T-t studies from the Rootshorga Complex yield isothermal decompression paths at ~ 800 – 900 oC with decompression from ~1.4 GPa at ~570Ma to ~700oC and ~0.7 GPa at ~500Ma whereas P-T-t estimates from the Jutulrora Complex are ~ 600 – 700 oC and <~0.8 GPa at ~500 Ma with a path consistent with crustal loading. The Rootshorga and Fuglefjellet Complex are inferred to comprise a mega-nappe, emplaced during the Kuunga Orogeny ~500 Ma ago, over the footwall Jutulrora Complex. Aerogravity, satellite gravity and seismic tomography data reflecting unusually thick crust are consistent with this interpretation.

著者

Yuki MORI Tomokazu HOKADA Tomoharu MIYAMOTO Takeshi IKEDA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.221124, (Released:2023-05-15)

被引用文献数

2

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We determined the metamorphic age and pressure–temperature conditions recorded in a sillimanite-garnet-bearing pelitic gneiss from Niban-nishi Rock, which is part of Niban Rock, on the Prince Olav Coast, eastern Dronning Maud Land, East Antarctica. Niban-nishi Rock is recognized as a component of the Lützow-Holm Complex (LHC), which is characterized by metamorphic age of 600–520 Ma and metamorphic grade of amphibolite to granulite facies. Electron microprobe U–Th–Pb monazite dating of the examined gneiss revealed that, unlike the typical exposures of the LHC, Niban-nishi Rock experienced Tonian metamorphism at 940.1 ± 9.8 Ma (2σ level), and is thus more similar to the neighboring exposures of Cape Hinode and Akebono Rock. Small numbers of younger monazite ages of 827–531 Ma were also detected, and some of which might relate to the metamorphism of the LHC. Phase equilibrium modeling and geothermobarometry indicate metamorphic conditions of 690–730 °C/0.38–0.68 GPa and 620–670 °C/0.42–0.60 GPa for peak and retrograde stages, respectively. The obtained peak temperature is lower than that of typical exposures in transitional- and granulite-facies zones of the LHC, such as Akarui Point and Skallen. Metamorphic features of Niban-nishi Rock, such as the upper amphibolite-facies condition and occurrences of garnet with retrograde zoning and sillimanite in the matrix, differ from those of Cape Hinode and Akebono Rock, with the former belonging to granulite facies and the latter showing kyanite in the matrix and garnet with growth zoning. Investigating Niban-nishi Rock is key in revealing the tectonic relation between the LHC and Cape Hinode (the Hinode Block). Further field surveys are required to reveal the metamorphic variations and the relations among exposures on the Prince Olav Coast.

著者

蟹沢 聰史

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.48, no.2, pp.67-75, 1962-08-05 (Released:2008-08-07)

参考文献数

5

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The Ryoke metamorphic rocks of the Takato district are composed mainly of pelitic and psammitic rocks, with subordinate amounts of basic volcanic rocks and limestone. The grade of metamorphism of the district increases progressively from the northwest to the southeast. Petrofabric analysis has been carried out for biotite, muscovite and quartz in the pelitic schistose hornfelses and gneisses of the district. Biotite and muscovite fabrics are generally determined by the bedding schistosity, and quartz fabrics of the schistose hornfelses show weak symmetry and ac-girdle, while those of the gneisses do not show any symmetrical pattern. When compared with those of the Yanai district belonging to the Ryoke metamorphic belt in southwestern Japan, the fabric diagram mentioned above are less symmetrical. This fact may suggest that the movement during the Ryoke metamorphism was different between the Takato and the Yanai districts.

著者

中川 善兵衛 小坂 丈予 浦部 和順 山田 久夫

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.67, no.9, pp.283-290, 1972-09-05 (Released:2008-08-07)

参考文献数

12

被引用文献数

1 2

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The weathering process of quartz-diorite mass in Senmaya district, Iwate Prefecture, was studied from chemical and mineralogical angles. Especially the relationship between the compositional changes of the weathered rocks and their main constituent minerals was detailedly discussed. The non-altered quartz-diorite is chiefly composed of quartz, plagioclase, hornblende and biotite, together with few apatite and magnetite. As weathering proceeds, most of the primary minerals, plaigoclase, hornblende and biotite, are gradually eliminated and secondary minerals such as vermiculite, kaolin etc. appear in stead. The change in chemical composition of the weathered rocks is almost controlled by the solubility of each chemical component under netural conditions. Among the primary minerals, biotite is most sensitive for weathering, the sequence of the alteration being as follows:biotite-hydrobiotite-vermiculite-kaolin mineral In the earlier stage of the weathering, the alteration process of biotite was mostly affected by its original crystallographic structure, so that the change in chemical composition of that mineral differs markedly from that of the host rock. But it is also controlled by the solubility of each chemical component, thus the compositional change becomes to be similar to that of the host rock in the later stage.

著者

竹内 常彦 舟山 裕士 山岡 一雄 阿部 宏

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.54, no.4, pp.113-126, 1965-10-05 (Released:2008-08-07)

参考文献数

29

被引用文献数

1 1

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The Obanazawa mine is situated about 9.5km north-east of Obanazawa City, Yamagata Prefecture, northeastern Japan. The ore deposit is made up of copper-zinc quartz veins developed in dacite and dacitictuff of Miocene age. Ore minerals are chalcopyrite, sphalerite, pyrite, tetrahedrite and ferberite. The pyrite has either pentagonal dodecahedral form or colloform textures. This is the first occurrence of ferberite in the green tuff region of the inner zone of northeastern Japan. Hexagonal; platy crystals of pyrite are observed in the vein found in the Komatazawa valley. It seems that they were crystallized as pyrrhotite single crystals and altered to pyrite aggregates after the formation of the vein. Gangue mineral is quartz accompanied by a small amount of barite. Argillization (mainly sericitization) and silicification are distinguished. Ferberite was identified by means of X-ray and chemical analysis; the composition is (Fe0.90 Mn0.10)WO4. Occurrence of ferberite and pyrite after pyrrhotite means that the veins may have formed at high temperature but the properties of other vein minerals suggest that they crystallized at low temperature. They have been explained as a telescoping phenomena of xenothermal type deposits in the greentuff region. The Obanazawa mine is situated at the intersection of N-S and NWSE main structural lines of northeastern Japan ; the basement of this area seems to be uplifted. The mineral assemblages of this ore deposit may be explained by assuming that a subvolcanic magma chamber exists in this area.

著者

代 開秋 津末 昭生 本間 弘次

出版者

Japan Association of Mineralogical Sciences

雑誌

岩鉱 (ISSN:09149783)

巻号頁・発行日

vol.88, no.5, pp.247-264, 1993-05-05 (Released:2008-03-18)

参考文献数

40

被引用文献数

5 5

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From the mode of occurrence, texture, and mineral assemblage, granitic rocks in the Kashiwa-jima-Okinoshima district are classified into four groups; namely, the Tanijiri-type granodiorite (abbreviated to TGd), the Tanijiri-type granodiorite porphyry (TGdp), the Moshima-type medium-grained granite (MmGr), and the Moshima-type fine-grained granite (MfGr). The similarity of major and trace element chemistry of the TGd and TGdp, and of the MmGr and MfGr suggests that the petrogenetic processes operating were similar, respectively. The Rb-Sr isotopic analyses of nine whole-rock samples of the Moshima-type granitic rocks (MmGr and MfGr) yield an age Rb-Sr of 16±2 Ma with an initial 87Sr/86Sr ratio of 0.70740± 0.00018. From the data of Nd and Sr isotopic ratios (Fig. 9) and of initial 87Sr/86Sr ratios and reciprocals of the strontium concentration (Fig. 10), it is suggested that the Tanijiri-type granodioritic rocks have been formed by mixing of an original S-type magma and sedimentary rocks of the Shimanto belt, while the Moshima-type granitic rocks have been formed by fractional crystallization of a S-type magma, which has been more felsic than the original S-type magma. From the chemical composition of garnet in the TGdp, it is suggested that the original S-type magma of the Tanijiri-type granodioritic rocks may have been generated by the partial melting of metamorphic rocks of pelitic and psammitic origin at a depth of about 20km. The TGdp shows a distinct porphyritic texture compared with the TGd. Minerals, such as plagioclase, orthopyroxene, cordierite, and biotite in the TGd have slightly wider range of solid solution compared with the minerals in the TGdp. Therefore, it is suggested that the petrogra-phical difference between the TGd and TGdp may have been caused by a difference in the ascent and cooling rate of their magmas.

著者

加納 博

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.75, no.Special2, pp.375-383, 1980-08-30 (Released:2012-08-03)

参考文献数

59

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The Aubukuma Metamorphic Belt is famous by the petrological work of Miyashiro (1958, etc. ). But his scheme on the metamorphic history has been largely rewritten by the Research Group of the Abukuma Plateau including Y. Kuroda, K. Uruno, K. Nureki, I. Hara, S. Kanisawa, T. Maruyama, H. Umemura and the author who proposed the hypothesis of polymetamorphic basement. The hypothesis has been evidenced, first, by the discoveries of polymetamorphic relics - of kyanite and staurolite from the Gosaisho-Takanuki metamorphic rocks and secondly, by the confirmation of Rb-Sr isochron ages of 400 to 600 m. y. of the Ishikawa, the Miyamoto, and the Samegawa plutonic masses. Since 1963 they have been engaged with research from such standpoint and the up-to-date data has been published in the memoir titled “The Basement of the Japanese Islands”However the idea of the polymetamorphic basement should be desce n ded from the “Diaphthoritic Rocks” prese nted by K. Sugi (1935) and his first finding of staurolite from Shiiohira coal mine. The detailed review will be described in the text.

著者

Yoshikuni Hiroi Tomokazu Hokada Tatsuro Adachi Kazuyuki Shiraishi Yoichi Motoyoshi Edward S. Grew

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.221209, (Released:2023-03-28)

被引用文献数

3

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Grandidierite, (Mg,Fe)Al3O2(BO3)SiO4, was found in a garnet-clinopyroxene-ilmenite-rich mafic granulite from Austhovde in the Late Neoproterozoic to Early Cambrian Lützow-Holm Complex (LHC), East Antarctica, the first reported occurrence of this borosilicate in a mafic granulite. It occurs in one of the many nanogranitoid inclusions (NIs) in garnet. Quartz, sodic plagioclase, myrmekite, K-feldspar, epidote and biotite are also found only as inclusions in garnet. Garnet porphyroblasts show marked compositional zoning: Ca increases and Mg decreases from the core to rim with little change in Fe and Mn contents except for the outermost rim. Anorthite content of inclusion plagioclase increases from core to rim of host garnet in parallel with increase in garnet Ca towards the rim. This together with the distinctly different mineral assemblages within and exterior to garnet porphyroblasts suggests that partial melting took place and produced melts were extracted leaving a mafic and calcic restite. Partial melting also occurred locally in garnet porphyroblasts consuming different hydrous mineral inclusions to produce various NIs ranging from K-feldspar-rich to K-feldspar-free. Subsequent decompression at high temperatures resulted breakdown of garnet to orthopyroxene + calcic plagioclase with further consumption of quartz, such that none remained in the matrix of the granulite. Grandidierite may have formed by a reaction between a trapped boron-bearing aluminous granitic melt and host garnet upon cooling.

著者

土屋 範芳 鈴木 舜一 小田 幸人 飯島 章夫

出版者

Japan Association of Mineralogical Sciences

雑誌

岩鉱 (ISSN:09149783)

巻号頁・発行日

vol.84, no.3, pp.89-96, 1989-03-05 (Released:2008-03-18)

参考文献数

44

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Carbonaceous material in pelitic rocks and limestones of the Ayukawa and the Daioin Formations in the Hitachi metamorphic rocks was investigated by means of X-ray powder diffraction technique. Carbonaceous material in these metasediments was graphitized under the conditions of greenschist facies. rystallite thickness Lc (002) ranges from 29 to 170 Å in the Ayukawa Formation and that from 120 to 300 Å in the Daioin Formation. Lc (002) of carbonaceous material in pelitic rocks containing biotite is more than 60 Å and increases with increasing metamorphic grade. Lc (002) value at a boundary between greenschist and epidote-amphibolite facies may be estimated 260-300 Å from the data of Lc (002) of the lower part of the Daioin Formation. Lc (002) of the Ayukawa Formation surrounding the sheared granite is above 200 Å. As compared with the general value of the Daioin Formation, Lc (002) of the Daioin Formation around the sheared granite is not so high. Thermal effect of the sheared granite was not marked, which suggests that the sheared granite intruded under low temperature condition.

著者

Tadashi YOKOYAMA Satoki SHINTAKU Naoki NISHIYAMA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.221107, (Released:2023-03-11)

被引用文献数

1

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Rocks have pores of various sizes. We investigated which pore sizes filled with water and in what order with the progression of water infiltration. The pore radii of the sandstone mainly ranges from a few µm to several tens of µm. Water was passed through the sandstone core at 25 °C, and water saturation, S, was adjusted to 63%, 67%, 71%, 87%, and 100%. At each S, the porewater radius distribution was measured using the water expulsion method, in which water in pores of a given pore radius was expelled by gas pressure. The results showed that the porewater radius distribution was approximately the same for S = 63-71%. As S increased from 71% to 100%, the pores with 4-10 µm and 10-20 µm radii were filled with water first, followed by pores with 20-52 µm radius. For S = 63-71%, water was considered to have entered via adsorption on the pore walls and capillary action at the corners of the pore. Because this water cannot be expelled by gas pressure, an increased amount of water was not detected by the water expulsion method. As for the results at S >71%, a theoretical model of the dissolution of entrapped air, assuming a cylindrical shape, showed that the length of the trapped air decreases faster in pores with small radii than in those with large radii. This may be a major explanation for the experimental result, which showed that pores with small radii fill with water more quickly than those with large radii.

著者

Kei-ichiro Murai Koyumi Yamashita Ginga Kitahara Makoto Tokuda Akira Yoshiasa

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.220901, (Released:2023-03-11)

被引用文献数

2

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Single crystals of CaW1-xMoxO4 scheelite-powellite solid solutions (x= 0.0, 0.03, 0.08, 0.2, 0.3, 0.5, 0.8 and 1.0) were synthesized using a melting method. The light emission spectra of the solid solutions were measured using a JASCO FP-8300 fluorescence spectrometer. The maximum fluorescence peak at 419 nm in the CaWO4 scheelite end-member greatly decreases in intensity and shifts its peak position to 451 nm with only 3% Mo substitution. The change in near-ultraviolet light emission intensity at 292 and 301 nm are more moderate than those in the strong peak at 419 nm. The tendency of change in intensity and wavelength shift due to the Mo substitution differs among these fluorescence peaks. Single crystal X-ray diffraction experiments for the CaW1-xMoxO4 solid solutions (x= 0.0, 0.2, 0.3, 0.5, 0.8 and 1.0) were carried out using a Rigaku Super-Nova Single source at offset/far HyPix3000 diffractometer. The R1 index for CaW1-xMoxO4 solid solutions were convergent to 1.22 -1.71% using anisotropic temperature factors. The expansion of the c-axis and shrinkage of the unit cell volume were induced with an increase in Mo content. The significant increase in the angle ∡Ocloser-Ca-Ocloser was directly related to the expansion of the c-axis. The Debye temperature ΘD for Ca, W and O atoms in CaWO4 were 381, 198 and 534 K, respectively. The obtained ΘD for Ca, Mo and O atoms in CaMoO4 were 363, 257 and 503 K, respectively. The phonon density of states estimated from the lattice dynamics calculations coincided with the observed ΘD values.

著者

Yasuyuki BANNO Koichi MOMMA Ritsuro MIYAWAKI Michiaki BUNNO

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.220724, (Released:2023-02-04)

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Katoite, ideally denoted as {Ca3}[Al2](□xSi3-x)(OH)4xO12-4x, where 1.5 < x ≤ 3, was found in skarn xenoliths from Tadano, Fukushima Prefecture, Japan, and investigated by electron microprobe analyses, X-ray single crystal structure refinement, and infrared (IR) spectroscopy. Katoite characteristically contains up to 0.18 atoms per formula unit (apfu) of S and has a range of compositions, wherein Si = 0.96-1.25 apfu, Al = 1.47-1.74 apfu, Fe = 0.13-0.28 apfu, and Mg = 0.01-0.10 apfu. A difference Fourier map revealed the residual electron density near the octahedral Y site (Wyckoff position = 16a), and we interpreted that S with three-fold coordination occurs at the position of the residual electron density, which is represented as the Y’ site (Wyckoff position = 32e). The final refinement introduced the Y’ site to yield R1 [F2 > 2σ(F2)] = 0.0353 with space group Ia3d and unit cell parameter a = 12.24095(8) Å. The IR spectrum in the range of 800-1200 cm-1 shows a band at 1124 cm-1 due to ν3(SO4) and doublet bands at 879 and 931 cm-1 with different absorbances interpreted as ν3(SiO4) overlapping with ν3(SO3). The combined results of IR spectroscopy and structure refinement imply that in the Tadano katoite, S4+ and S6+, forming (SO3)2- and (SO4)2- coordinations, are placed at the Y’ and tetrahedral Z sites, respectively. Assuming that S is preferentially allotted to the Y’ site as S4+ to compensate for the deficiency of the octahedral cations Al, Fe, Mg, Mn, and Ti at the Y site, chemical formulae, including possible S4+ and S6+ contents, may be calculated. The average chemical formula for 14 different spots is as follows: {Ca3}[(Al1.614Fe3+0.208Mg0.063Ti0.019)Σ1.90S4+0.096]Σ2.00(□1.867Si1.120S6+0.013)Σ3.00[(OH)7.192O4.612F0.147Cl0.048]Σ12.00.

著者

桃井 斉

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.71, no.Special1, pp.133-142, 1976-07-15 (Released:2012-08-03)

参考文献数

40

著者

坂本 尚史 鈴木 滋 立松 英信 大塚 良平

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.75, no.5, pp.164-171, 1980-05-05 (Released:2008-08-07)

参考文献数

6

被引用文献数

1 3

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青函トンネルの先進導坑,北海道方約5000mの地点において,新第三紀訓縫層中の断層を埋めて産する茶褐色の鱗片状鉱物がサンコーコンサルタント,伊藤昌史氏により発見された。この試料は,早稲田大学鞠子正教授を経て筆者らに提供され,その後の室内研究により我国での3番目の産出である鉄セピオライトであることが明らかにされた。 化学分析値から計算された脱水相の単位胞の1/2構造式は以下の通りである。 (Si11.49Ti0.03Al0.38Fe3+0.10)12.00(Fe3+1.25Fe2+0.26Mn0.02Mg6.00)7.53O32・Ca0.03Na0.05K0.04 一方,FeをすべてFe2+であるとしてO30(OH)4をもとにして構造式を計算すると (Si11.74Ti0.03Al0.23)12.00(Al0.16Fe2+1.65Mn0.02Mg6.13)7.96O30(OH)4・Ca0.03Na0.05K0.04 となり,理想式によく一致する,従って,この鉄セピオライト中のFeは当初Fe2+として形成され,その後酸化されたものと考えられた。 この論文では,このほかに,X線回折データ,熱分析データ等の鉱物学的データが示されている。

著者

Massimo NESPOLO Tohru OZAWA Yusuke KAWASAKI Kazumasa SUGIYAMA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.107, no.6, pp.226-243, 2012 (Released:2012-12-29)

参考文献数

32

被引用文献数

7 10

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The structure of quatrandorite is reported for the first time from an untwinned sample from Oura mine, San Jose, Bolivia. The mineral crystallizes in P21/c, a = 19.1686 (19) Å, b = 17.160 (3) Å, c = 13.042 (2) Å, β = 90.008 (12)°, V = 4289.9 (11) Å3, Z = 4. Refinement to Robs = 5.66% was obtained with Jana2006. Quatrandorite belongs to the andorite series, whose members share two cell parameters while the third can be expressed as n × 4.3 Å, with n = 2, 4 and 6 for ramdohrite (uchucchacuaite, fizelyite), quatrandorite and senandorite, respectively. Both quatrandorite and senandorite are strongly pseudosymmetric up to Cmcm with one parameter corresponding to n = 1 (∼ 4.3 Å). The hypothetical structure corresponding to Cmcm is also the aristotype common to both minerals. The strong structural similarity of quatrandorite and senandorite may explain their co-existence in some samples, which has in the past led to hypothesize the existence of a further member of the series, nakaséite, which was however later shown to consist of a random stacking of the two minerals. The Cmcm aristotype is not common to the n = 2 minerals (uchucchacuaite, ramdohrite, fizelyite), which are thus structurally less closely related to the two other members. A common aristotype to all three minerals can nevertheless be obtained via a different path, which leads to Cmme with the same cell parameters as Cmcm; the degree of pseudo-symmetry in this supergroup is however lower and there remain a difference in one sulfur position in this aristotype. It nevertheless confirms previous reports in the literature stating that the bulk of the structure of the minerals of this series can be reduced to a common principle, essentially a distorted galena; the departures from it are however crucial for the realization of the individual structures.

著者

Daiki FUKUYAMA Keiji SHINODA Daigo TAKAGI Yasuhiro KOBAYASHI

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.117, no.1, pp.220506, 2022 (Released:2022-10-18)

参考文献数

21

被引用文献数

2

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The compositional dependence of the intensity and electric field gradient (EFG) tensors for Fe2+ at the M1 sites, Fe2+ at the M2 sites, and Fe3+ at the M1 sites in Ca–rich pyroxene were obtained from Mössbauer spectra of crystallographically oriented single–crystal thin sections of four Ca–rich natural pyroxenes. Components of the intensity tensor (IXX, IYY, IXY, and IZZ) for Fe2+ at the M1 sites in Wo50 Ca–rich pyroxene were almost the same; the averages of the IXX, IYY, IXY, and IZZ components were 0.342, 0.477, 0.039, and 0.681, respectively. Intensity tensor for Fe2+ at the M1 sites of Wo40 Ca–rich pyroxene was different from the Wo50. Whereas principal axes of EFG tensors for Fe2+ at the M1 sites of Wo50 pyroxenes had the same direction, principal axes of VXX and VYY of EFG of Wo40 had different directions from that from Wo50. The difference of intensity and EFG tensors between Wo50 and Wo40 suggests that the intensity and EFG tensors for Fe2+ at M1 sites are dependent on the Ca contents and are independent of Fe contents. Some intensity and EFG tensors for Fe2+ at the M2 sites and Fe3+ at the M1 sites in Ca–rich pyroxene were also obtained. However, the compositional dependence of the intensity and EFG tensors has yet to be clarified, because the number of examples is insufficient.

著者

渡邉 克晃 北川 隆司

出版者

Japan Association of Mineralogical Sciences

雑誌

日本鉱物学会年会講演要旨集

巻号頁・発行日

pp.77, 2004 (Released:2005-03-10)

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はじめに 露出している岩石表面にはしばしば地衣類の生育が観察される。地衣‐岩石接触面では地衣類による物理的・化学的変質作用が起こっており、一次鉱物の微小片や、粘土鉱物および鉄の酸化物・水酸化物などの二次生成鉱物が接触面に沿って保持されることが知られている(Banfield et al., 1999)。そしてこれらの生成物に地衣体の遺骸が加わることで、土壌前駆物質としてのはたらきを有することになり、こうした現象は初生的な土壌生成作用であるとみなすことが出来る(大羽・永塚,1988)。 近年の急速な都市化によって天然の岩石・土壌は様々な人工基物で覆われるようになり、それに伴い人工基物表面にも地衣類の生育が観察されるようになった。ただしその種類数、個体数は著しく貧弱である。代表的な人工基物であるアスファルトおよびコンクリートは、その主成分が破砕岩石片であるにもかかわらず、天然の岩石表面と比べて地衣類の生育が制限されている。人工基物と地衣類との間ではどのような作用が起こっているのか、地衣‐花崗岩接触面での現象と比較した結果を報告する。試料採取および実験方法 人工基物(アスファルトおよびコンクリート)表面に生育する地衣類のサンプルとして、固着地衣類Porpidiaを広島県東広島市の市街地から採取した。また、花崗岩表面に生育する地衣類のサンプルとして、同じく固着地衣類Porpidiaを広島県本郷町から採取した。 採取したそれぞれの試料の薄片試料を作成し、偏光顕微鏡観察とEPMAによる化学分析を実施した。結果 花崗岩‐地衣接触面では、花崗岩構成鉱物である黒雲母と地衣類との間で物理的破壊現象および化学的変質現象が認められた。しかし、他の構成鉱物である石英および長石類との接触面でははっきりとこれらの現象を確認できなかった。一方、人工基物‐地衣接触面では、構成鉱物と地衣類との間に明瞭な相互作用を見出すことができなかった。文献・ 大羽裕・永塚鎮男(1988)土壌生成分類学,122-126.・ Banfield et al. (1999) Biological impact on mineral dissolution. Pro. Natl. Acad. Sci., USA. 96, 3404-3411.