著者

Ibuki KINEBUCHI Atsushi KYONO

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.116, no.4, pp.211-219, 2021 (Released:2021-10-14)

参考文献数

47

被引用文献数

5

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The oxidation process from magnetite to hematite through maghemite was investigated by X–ray diffraction (XRD) and X–ray absorption spectroscopic techniques. The XRD pattern of magnetite heated at 100 °C for 3 h showed small reflections of maghemite with partially ordered distribution of vacancy (space group P4132 or P4332). Thereafter, the XRD pattern of magnetite heated at 250 °C for 3 h exhibited extra reflections corresponding to the tetragonal maghemite with fully ordered distribution of vacancy (space group P41212 or P43212). Diffraction peaks of hematite occurred from the magnetite heated at 250 °C, in which maghemite and hematite coexisted with magnetite. Diffraction peaks of magnetite subsequently disappeared at 300 °C. Instead, maghemite and hematite dominated the XRD pattern, but the amount of maghemite reduced from 300 °C. The maghemite completely disappeared at 500 °C, and hematite finally dominated the XRD pattern. Rietveld fitting results clearly showed that the a lattice parameter and site occupancy factor of Fe at the octahedral site continuously decreased at the temperatures from 25 to 300 °C. The X–ray absorption near edge structure (XANES) result showed that the Fe3+/ΣFe increased up to 300 °C and remained constant until 500 °C, indicating that Fe2+ in oxidized magnetite was completely oxidized to Fe3+ at 300 °C. Furthermore, the intensities of radial structure function (RSF) peaks at 1.7 and 3.1 Å corresponding to the Fe–O bonds in octahedral site and the Fe–Fe interaction between the octahedral sites reduced continuously from 25 to 300 °C. The fitting results of the first shells indicated that the coordination number and site occupancy factor at the octahedral site continuously decreased at the temperature range from 25 to 300 °C, which were approximately consistent with those of Rietveld fitting analysis. The a lattice parameter of the oxidized magnetite displayed a linear trend between stoichiometric magnetite and stoichiometric maghemite with a relationship of a = 0.0985x + 8.3397 (x = Fe2+/Fe3+). It was clearly confirmed that during the magnetite oxidation, Fe was continuously removed from the octahedral sites, which resulted in the formation of maghemite with partially ordered distribution of vacancy. Just after magnetite oxidation was completed, the vacancy ordering further progressed by the diffusion of Fe3+ within the structure, leading to the formation of maghemite with fully ordered distribution of vacancy.

著者

Tatsuki TSUJIMORI Hiroshi MIYAJIMA Ritsuro MIYAWAKI

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.112, no.5, pp.181-183, 2017 (Released:2017-11-15)

参考文献数

17

被引用文献数

1

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Gem sparkles deep: Preface of the special issue on ‘Jadeite and jadeitite’

著者

Tatsuki TSUJIMORI George E. HARLOW

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.112, no.5, pp.184-196, 2017 (Released:2017-11-15)

参考文献数

92

被引用文献数

4 15

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Jadeitite, known as ‘hisui’ in Japan, has been esteemed as sacred stone in both ancient and modern Japanese cultures. Although it was thought that the source material of Japanese jadeitite was brought from China, the identification of jadeite in 1939 changed this interpretation. Japanese jadeitites and jadeite–rich metasomatic rocks are found in Paleozoic and also Mesozoic geotectonic units. All localities are situated in serpentinite mélange with high–pressure metamorphic rocks and/or serpentinite lenses within a high–pressure metamorphosed complex. Outcrop exposures of contact between jadeitite and host serpentinite are extremely rare. Normally the jadeitites show lithological heterogeneity in the same locality due to multiple deformation, recrystallization, and metasomatic fluid infiltration. Studies over the last two decades have interpreted jadeitite in worldwide either as the direct aqueous fluid precipitate (P–type) from subduction channel into the overlying mantle wedge, as the metasomatic replacement (R–type) by such fluids of oceanic plagiogranite, graywacke, or metabasite along the channel margin, or a combination of these two processes. Japanese jadeitites are classified into one or the other type. Multiple stable isotope characterization analyses for jadeitite and related metasomatic rocks and serpentinite become increasingly important to decode fluid behaviors in past subduction zone. However, available geochemical data on Japanese jadeitite are very limited in comparison with other studied localities. More systematic research will unlock new insights about fluid flow and its impacts at the bottom of forearc mantle where jadeitites form. Chemical differentiation and transportation of the fluids involved in jadeitite–formation are crucial topics requiring further research. Nevertheless, the designation of jadeite (and jadeitite) as the national stone of Japan by the Japan Association of Mineralogical Sciences in 2016 should bolster education of the public about this revered stone and its role in subduction zone processes.

著者

Hidetomo HONGU Akira YOSHIASA Ginga KITAHARA Yumiko MIYANO Karin HAN Koichi MOMMA Ritsuro MIYAWAKI Makoto TOKUDA 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

pp.200904, (Released:2021-09-30)

被引用文献数

2

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Parasymplesite and vivianite specimens were obtained from Kiura Mine, Ohita, Japan and Tomigaoka, Nara, Japan, respectively. Empirical chemical formulas of the specimens determined by energy–dispersive X–ray spectroscopy on the scanning electron microscopy were Fe3(AsO4)2·8H2O, and (Fe0.93Mn0.06Mg0.01)3(PO4)2·8H2O, respectively. The crystal structures of parasymplesite and vivianite determined by single–crystal X–ray diffraction method were monoclinic, space group C2/m, with unit–cell parameters: a = 10.3519(10), b = 13.6009(13), c = 4.7998(4) Å, β = 104.816(2)°, V = 653.32(11) Å3 (Z = 4), and monoclinic, space group C2/m, with unit–cell parameters: a = 10.1518(6), b = 13.4327(7), c = 4.7005(3) Å, β = 104.692(2)°, V = 620.03(6) Å3 (Z = 4), respectively. The crystal structure of parasymplesite solved with the ideal chemical formula was refined to the R1 value of 0.0301 (wR2 = 0.0788) for 722 independent reflections with |Fo| > 4σ(|Fo|), whereas that of vivianite was refined to the R1 value of 0.0272 (wR2 = 0.0832) for 664 independent reflections. The hydrogen atom positions determined by the difference Fourier method coincided with the positions where residual electron density peaks appeared. In the edge–sharing Fe2O6(H2O)4 double octahedra in parasymplesite and vivianite, the bond distance of Fe2–O5, where O5 is the oxygen atom of the H2O molecule, is shorter than that of Fe2–O2. In each arsenate and phosphate phase, only the M2–O2 bond distance shows an increase trend with the increase in the average ionic radii of the M2 site, but the M2–O3 bond distance never shows a clear average M2 ionic radius dependence. In vivianite group minerals, a distortion at the isolated M1O2(H2O)4 octahedra increases as a function of the average M1 ionic radius. The respective complex sheets consisting of the TO4 tetrahedra, isolated M1 octahedra, and edge–sharing M2 double octahedra are connected only by the hydrogen bond O5–H52•••O4. In the arsenate phases, the donor–acceptor distance between O5 and O4 exhibits an increase trend as increase of the average M ionic radius, but in the phosphate phases, there is no clear correlation between donor–acceptor distances and the average M ionic radius.

著者

Yasuyuki BANNO Koichi MOMMA Ritsuro MIYAWAKI Shigeo YAMADA

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.114, no.1, pp.33-40, 2019 (Released:2019-03-08)

参考文献数

20

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Chemically heterogeneous amphibole, ranging in composition from magnesio–riebeckite through ferri–ghoseite to clino–suenoite, was found in a specimen of Sanbagawa quartz schist from the Iimori region of the western Kii Peninsula, central Japan. The amphibole exhibits a continuous solid solution between BNa and BMn2+ (BMn2+ = 0–1.82 atoms per formula unit). Most of the amphibole crystals comprise a Mn–poor core and a Mn–rich rim, and ferri–ghoseite often occurs near the boundary between core and rim. The crystal structure of a single crystal fragment of ferri–ghoseite, which has an averaged composition of A(Na0.16K0.02)Σ0.18B(Na0.83Ca0.09Mn2+1.08)Σ2.00C(Mg3.78Mn2+0.52Fe3+0.66Al0.04)Σ5.00T(Si7.95Al0.05)Σ8.00O22W[(OH)1.90F0.10]Σ2.00 based on electron–microprobe analyses, was refined to a R1 of 6.7%, has unit cell parameters of a = 9.6389(7), b = 18.0534(10), c = 5.3138(3) Å, and β = 102.896(2)°, and is in space group C2/m with Z = 2. The site populations for B cations of the ferri–ghoseite are M4(Na0.83Ca0.09)M4’Mn2+1.08, which also confirms the B(Na,Mn2+) solid solution. Sector–zoned aegirine occurs in the amphibole–bearing quartz schist from Iimori, and it is assumed that most of the metamorphic minerals in the quartz schist formed under non–equilibrium conditions. Therefore, taking into account the miscibility gap between sodium amphibole and clino–suenoite, the solid solution between BNa and BMn2+ in the amphibole can be inferred to have resulted from rapid, non–equilibrium crystallization rather than high–T equilibrium crystallization.

著者

八木 健三 茅原 一也

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.49, no.1, pp.22-28, 1963

被引用文献数

1

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男鹿半島南海岸双六部落の凝灰角礫岩中の角礫として,少量ながらコメンド岩が産出する.その地質層準は中部中新世の男鹿層群中の立由崎凝灰岩部層と考えられる.その構成鉱物はサニデイン,石英,アルフェド角閃石,エジリン及び鉄鉱などで,化学組成はSiO2.とNa2Oにとみ,典型的なコメンド岩に属する.これは東北日本におけるコメンド岩の最初の産出で,第三紀火成活動史よりみて,その岩石区的意義を検討した.

著者

南部 松夫 谷田 勝俊

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.65, no.1, pp.1-15, 1971-01-05 (Released:2008-08-07)

参考文献数

14

被引用文献数

6 7

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Chemical analysis of takanelite a new manganese dioxide mincral from Nomura mine, Ehime Prefecture gave; MnO270.39, MnO 13.06, MgO 0.22, CaO 2.66, BaO none, Na2O 0.05, K2O 0.05, Fe2O3 1.34, Al2O3 1.70, TiO2 trace, SiO2 3.61, H2O(+) 4.92, H2O(-) 2.22, sum 100.22%. After deducting Al2O3, SiO2, Fe2O3, H2O(-) and a part of H2O(+) (present as halloysite, goethite and quartz), it corresponds to (Mn+20.89 Ca0.23 Mg0.03)1.15 Mn+43.94 O9.00 1.3H2O as O=9, or ideally (Mn+2, Ca) Mn4+4O9•nH2O with Mn+2〉Ca and n=1.3. This is the Mn+2 analogue of rancieite, (Ca, Mn+2) Mn+44O9•nH2O with Ca〉Mn+2 and n=3. Electron microprobe analyses of five different grains, using analysed rancieite, nsutite and todorokite as standards, gave Mn 60.5-62.3 and Ca 2.0-2.4, and Fe, Al and Si were not detected. These results validate the above analysis and deduction of impurities. Analyses of some other materials suggest the possible existence of a continuous solid solution series between rancieite and this mineral. X-ray powder data are very similar to those of rancieite by Sorem and Gunn (1967) and by Richmond, Fleischer and Mrose (1969), and includes the strongest lines 7.57 (100) (1010), 4.43 (10b) (0002, 1120), 3.76 (25) (2020), 2.462 (15) (1123), 2.349 (20) (2023), 2.065 (10) (2133), 1.754 (7) (2243, 1015), 1.420 (17) (5052, 4260, 1126). The indexing is based on the hexagonal cell with a0=8.68Å, c0=9.00Å, Z=3. Colour steel gray to black, luster submetalic to dull, streak brownish black, sp. gr. 3.41 (measured on impure material); 3.78 (calculated). Cleavage not observed. Vickers' hardness (load 100g) 480kg/mm2(average). In reflected light, yellowish gray, reflection pleochroism weak with yellowish white to yellowish light gray, anisotropism moderate with polarization colour of yellowish gray to light brownish gray. Etch reactions: HCI (conc.), HNO3(conc.) and H2SO4 (conc.) tarnish slightly grayish brown, H2SO4 (conc. ) +H2O2 (20%) and SnCl2 (sat.) quickly stain black. The mineral occurs as irregular-shaped nodules, 1-15cm across, composed of a microscopic intergorwth with a small quantity of braunite, halloysite, goethite and quartz, in the oxidation zone of the braunite-rhodochrosite-caryopilite bedded deposit at the Nomura mine, Ehime Prefecture, Japan, in low grade metamorphosed cherts of Permian age. The name is for the late Dr. Katsutoshi Takane (1899-1945), the former Professor of Mineralogy, Tohoku University, Sendai, Japan. Type material is preserved at Tohoku University. The mineral and name were approved before publication by the Commission on New Meinerals and Mineral Names, IMA.

著者

砂川 一郎

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.55-62, 1980-08-30 (Released:2012-08-03)

参考文献数

19

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Although mineral crystals grow in nature under a broad spectrum of conditions, most natural crystallizations are considered to occur in solution phases, including both high temperature and aqueous solutions. When crystals grow from solution phases, the solidliquid interfaces are essentially smooth, where two dimensional layer-by-layer growth are expected. Judging from growth rates versus supersaturation relation, dislcoation controlled growth is expected for the supersaturation region below σ*, and hopper growth due to twodimensional nucleation mechanism for σ*-σ**, hereas unstable dendritic growth above σ**. Various inhomogeneities in crystals as well as surface microtopographs of crystal OfaOces may appear depending on the growth conditions. It was found on the basis of observati ons on these properties of natural crystals that in most natural crystallization, sprial growth and two-dimensional nucleation mechanisms are predominant mechanisms. This is true not only for crystallization in magma and hydrothermal solutions, but also for crystallization in metasomatic environments. For crystal growth mechanism in regional metamorphic environment, the so-called Ostwald ripening is suggested as principal mechanism, where interstitial solutions play an essential role, and thus the growth is similar to that from solution phases.

著者

Euis T. YUNINGSIH Hiroharu MATSUEDA Ildrem SYAFRIE

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.113, no.6, pp.293-309, 2018 (Released:2018-12-29)

参考文献数

49

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Tellurium–bearing gold, silver, and base metal assemblages characterize the epithermal mineralization in southwestern Hokkaido, Japan. The telluride deposits in this district consist of quartz–filled fracture systems of Late Miocene to Pliocene age. Most of the telluride mineralization in southwestern Hokkaido consists of vein systems or are massive in form. The dominant host rocks for this deposit type are intermediate to acid volcanic rocks. The gangue and alteration minerals are very fine to fine–grained quartz, chalcedony, anatase, zeolite, sericite, barite, adularia, chlorite, smectite or other clay mineral, while carbonate (calcite and rhodocrosite) and Mn minerals are poorly represented and rarely coexist with tellurides. The country rocks suffered argillic and propylitic alterations, silicification, and kaolinitization. Tellurium–bearing mineralization is related to or co–exists with sulfide and sulfosalt mineralization. The tellurides identified in the studied area consist of native tellurium, hessite, stutzite, petzite, sylvanite, calaverite, tellurobismuthite, tetradymite, Se–bearing tetradymite, tellurantimony, goldfieldite, altaite, coloradoite, tellurite, teineite, and poughite. The first crystallized telluride minerals such as native tellurium, stutzite, petzite, sylvanite and hessite are followed by calaverite, coloradoite, tellurobismuthite, tellurantimony, and altaite, indicating a decline in tellurium activity during telluride deposition with time. Microthermometry of fluid inclusions in quartz and barite indicate that the mineralization formed at moderate temperatures, ranging from 250–200 °C with low average salinity (1.9–5.7 wt% NaClequiv.). The shift in mineralogy reflects decreases in temperature and fugacity of sulfur, with a concomitant increase in fugacity of tellurium. Further decrease in fugacity of tellurium (coupled with decreasing fugacity of sulfur) resulted in deposition of Au–Ag–Te and other tellurides.

著者

Yuma MORIMITSU Yohei SHIROSE Satomi ENJU Kenji TSURUTA Norimasa SHIMOBAYASHI

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.201130d, (Released:2021-04-27)

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Zaïrite was found from the quartz vein penetrating into the metamorphosed mudstone of the Wazuka Unit in Ishidera area, Wazuka–cho, Kyoto Prefecture, Japan, which is the first occurrence in Japan. Zaïrite occurs as bright–yellow granular crystals (20–30 µm) in a cavity formed by the leaching of fluorapatite with native bismuth inclusion. The chemical composition of zaïrite from Ishidera was closer to the ideal chemical composition, comparing with the zaïrite from type locality including Al. The empirical formula from electron probe microanalyzer (EPMA) analysis on the basis of O = 8, OH− = 6 was (Bi0.70Ca0.23)Σ0.93Fe3+2.91(P2.04S0.09O8)(OH)6. The unit cell parameters obtained from the X–ray diffraction (XRD) pattern were a = 7.311(3) Å and c = 16.407(7) Å, larger than the type locality due to difference in chemical composition.

著者

Masayasu KATOH Kenji SHUTO

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.0903060073, (Released:2009-03-10)

著者

Ginga KITAHARA Akira YOSHIASA Makoto TOKUDA Tsubasa TOBASE 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.116, no.1, pp.45-55, 2021 (Released:2021-03-06)

参考文献数

43

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Structural analysis of Ce– and Nb–perovskites containing Fe, Zr, Nb, and rare earth elements (REEs) in CaTiO3 perovskite was performed using single–crystal X–ray diffraction and X–ray absorption near–edge structure (XANES) analyses. Based on chemical analysis results, XANES measurements and the site–occupation of elements at A– and B–sites showed the chemical formula:(Ca2+0.817REE3+0.087Na+0.081Sr2+0.005Th4+0.003)1.998+0.993(Ti4+0.941Nb5+0.017Fe3+0.013V5+0.010Fe2+0.007Sc3+0.006Zn2+0.005Al3+0.002Ge4+0.001W6+0.001)3.996+1.003O3 for Ce–perovskite and(Ca2+0.937Ce3+0.021Na+0.020La3+0.015Sr2+0.003)2.008+0.996(Ti4+0.730Nb5+0.122Fe3+0.108Al3+0.020Zr4+0.009V5+0.008)3.990+0.997O3for Nb–perovskite. In Ce– and Nb–perovskites, the total charges at the A– and B–sites achieved near–ideal divalent and tetravalent states such as Ca2+Ti4+O3, respectively, due to complex elemental substitutions. Local distortions around Ti in the perovskite solid solutions were greater, and the pre–edge features of the Ti atoms in Ce– and Nb–perovskites were different from those in pure CaTiO3. The valence states and local structures of Fe in Ce– and Nb–perovskites were significantly different. The existence of divalent Fe2+ at the B–site in Ce–perovskite was confirmed. It is presumed that the displacement ellipsoids of all atoms and local irregularities in Ce–perovskite increase owing to the radiative decay of the actinoid element Th. We reconfirmed that the composition and three–dimensional structure of perovskite–type structures were flexible and caused various electrical, structural changes.

著者

Susumu IKEDA Yoshito NAKASHIMA Tsukasa NAKANO

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.114, no.1, pp.1-17, 2019 (Released:2019-03-08)

参考文献数

53

被引用文献数

1

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The three–dimensional (3–D) structure of crystals around the interface between massive potassium (K)–feldspar and quartz–feldspar intergrowth (graphic granite) of two samples collected from a pegmatite body in Ishikawa town, Fukushima Prefecture, Japan, was determined by X–ray computed tomography (CT). Based on the results and additional information obtained by serial thin section and polarizing observations, the formation processes of graphic granite and pegmatite bodies are discussed. The most important finding of the 3–D observation using X–ray CT is the very flat spatial distribution of the tips of the quartz crystals. The sharp interface between the graphic and single–phase parts suggests that the change from graphic granite to massive K–feldspar crystallization corresponds to the transition of the thermodynamic conditions at the growth front from non–equilibrium to equilibrium. This indication leads to a new model for the pegmatite genesis, that is, graphic granite forms at the marginal zone under non–equilibrium conditions shortly after the intrusion of magma due to rapid cooling by the cold host rock body and, subsequently, the crystallization of massive K–feldspar starts when the conditions at the crystal growth front reenter the ‘feldspar + melt’ field in the phase diagram due to the relaxation of the conditions. Other results related to the conditions of the growth environment with coexisting aqueous fluid, such as the connectivity of the quartz crystals, are also discussed, for example, the influence of the supercritical state on the nucleation of quartz crystals.

著者

大庭 昇 富田 克利 山本 温彦 大迫 暢光 井ノ上 幸造

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.10, pp.329-336, 1980-10-05 (Released:2008-08-07)

参考文献数

6

被引用文献数

4 5

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With respect to mineral and chemical compositions, microstructure, x-ray powder diffraction and grain-size distribution of volcanic ashes from Sakurajima Volcano, Kyushu, Japan, greyish black-colored “black ashes”, reddish dark grey-colored “red ash” and greyish white-colored “white ash” are compared with one another, and mechanisms of their formation are discussed. Many evidences show that the black ashes came from solidifying lavas, by which the summit crater had been buried, those which were explosively crushed and ejected by gas pressure which was accumulating within the vent. The red ash is considered possible to be a mixture of the preexisted and recent ashes which were affected by alteration due to action by volanic gases. Meantime, the white ash characterized by abundant vesiculated volcanic glasses seems to be that which was ejected continuously from magma which came up to the craters.

著者

Raiki YAMADA Hikaru SAWADA Shinnosuke AOYAMA Wataru OUCHI Sota NIKI Mitsuhiro NAGATA Toshiro TAKAHASHI Takafumi HIRATA

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.201125, (Released:2021-02-25)

被引用文献数

8

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The Hida granites, classified into the pre–Jurassic and Jurassic plutons in this study, are important components of the Hida belt, which is a Paleozoic–Mesozoic basement of the Japan arc and underwent Permian to Triassic metamorphism during the collision between the North and South China blocks. This study performed zircon U–Pb dating and whole–rock geochemical analyses for the Hida granites from the major plutonic bodies to reveal the geotectonic history and the origin of the Hida belt. Obtained 238U–206Pb weighted mean ages exhibit 239.1–238.3 Ma for the Katakaigawa body (augen granite) and 200.5–180.9 Ma for the other bodies (non–deformed granitoids), and these ages can be correlated to the pre–Jurassic and Jurassic plutons, respectively. Geochronological results suggest that the mylonitization forming augen granites of the pre–Jurassic plutons occurred during its intrusion and indicate that the Jurassic plutons are distributed widely in the Japan Sea side of the Hida belt. Meanwhile, geochemical characteristics of whole–rock major and trace element compositions indicate that the pre–Jurassic and Jurassic plutons seem difficult to distinguished geochemically and suggest that both of them are adakitic and non–adakitic granites generated in subduction zone.

著者

Teruyoshi IMAOKA Jun–Ichi KIMURA Qing CHANG Tsuyoshi ISHIKAWA Mariko NAGASHIMA Natsuki TAKESHITA

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.200721, (Released:2021-02-10)

被引用文献数

4

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We report in situ major and trace element and Li isotope analyses of murakamiite and Li–rich pectolite in an albitite and whole–rock analyses of the albitite and host granite from Iwagi Islet, SW Japan. The albitite forms small bodies that are several tens of centimeters to tens of meters in size, disseminated in a host granite of Late Cretaceous age. The studied murakamiite–bearing albitite contains albite, sugilite, aegirine–augite, quartz, murakamiite–Li–rich pectolite, microcline, katayamalite, and accessory minerals. It shows conspicuous strain–induced textures. The murakamiite and Li–rich pectolite form a solid solution with Li × 100/(Li + Na) atomic ratios ranging from 44.2 to 60.1, and the Na line profiles show a zoning structure in which Na decreases from core to rim. Major and trace element compositions of murakamiite–pectolite normalized to that of albitite indicate the enrichments of some elements, particularly in Mn, Ca, Li, Sr, and REEs, roughly on the same order of magnitude (~ 10 times). The albitite–normalized element concentrations vary systematically with ionic radius of the element; the normalized concentrations of cations with the same valence roughly form a simple convex parabolic curve when plot against the ionic radius. This indicates that the element partitioning of murakamiite and pectolite during metasomatism to form albitite took place under a strong control of crystal structure, quasi–equilibrated with metasomatic fluids and coexisting minerals. The δ7Li values of murakamiite and Li–rich pectolite show a wide range from −9.1 to +0.4‰ (average −2.9‰), and no obvious correlation with Li contents was observed. These δ7Li values should have resulted from hydrothermal fluid–rock interactions at the temperatures of 300–600 °C. The very low δ7Li values down to −9.1‰ may have originated from intra–crystalline Li isotope diffusion, or involvement of deep–seated, Li–Na–enriched subduction–zone fluids with low δ7Li values.

著者

Daisuke NISHIO-HAMANE Tetsuo MINAKAWA Hanako OKADA

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.109, no.1, pp.34-37, 2014 (Released:2014-02-22)

参考文献数

10

被引用文献数

2 6

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Iwateite, Na2BaMn(PO4)2 is a new mineral, which was found in the manganese ore of the No. 3 (Matsumaezawa) deposit in the Tanohata mine, Tanohata Village, Iwate Prefecture, Japan. Iwateite has a glaserite structure, which occurs as granular to anhedral inclusions of 10-100 μm in the main constituent minerals in manganese ore and sérandite crystal. It is colorless with white streaks, non-fluorescent, and it displays very weak pleochroism. Iwateite crystallizes in the trigonal system and belongs to the P3 space group where, a = 5.3642(10), c = 7.039(2) Å, V = 175.41(8) Å3, and Z = 1, with a calculated density of 4.06 g/cm3.

著者

片田 正人 高橋 一男 藤原 郁夫

出版者

Japan Association of Mineralogical Sciences

雑誌

岩鉱 (ISSN:09149783)

巻号頁・発行日

vol.86, no.3, pp.91-99, 1991-03-05 (Released:2008-03-18)

参考文献数

6

被引用文献数

1 1

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The Himekami pluton is a complex of mafic rocks and their differentiated felsic rocks, which belong to shoshonite rock association. The pluton is devided into three bodies: South pluton, North pluton and Shiroishi pluton. The South pluton, consisting mainly of monzonite, monzogabbro, quartz monzonite and quartz monzodiorite, is classified genetically into four groups of mafic and felsic rocks. Each rock group accompanies a few amounts of xenolithic mass of cumulated, ultramafic rocks and melagabbro. The North pluton is a zoned pluton of quartz monzonite, granite and granodiorite. The Shiroishi pluton is a leucocratic tonalite-granodiorite.

著者

Masaki ENAMI Shuaimin HUANG Motohiro TSUBOI Yuki WAKASUGI

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.181107a, (Released:2020-12-05)

被引用文献数

1

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The Tonaru epidote–amphibolite is one of the large metagabbro dominated bodies and occurs in schistose rocks of the Sanbagawa metamorphic belt, central Shikoku. This body locally retains mineral parageneses of eclogite facies equilibrium prior to the epidote–amphibolite facies stage. The lithologic boundary between the epidote–amphibolite and the surrounding schistose rocks was well observed along the Kokuryo River in the western part of the Besshi region in central Shikoku. Boundary zone of 1.5–2.5 m wide is developed between the epidote–amphibolite and pelitic schist. This zone is composed of a basic layer and alternating layers consisting of thin amphibole–rich and mica–rich bands, which occupy the epidote–amphibolite and pelitic schist sides, respectively. The basic layer has a chondrite–normalized rare–earth element (REE) pattern with slight enrichment of light REEs, which corresponds to epidote–amphibolite. By contrast, the amphibole–rich band has a flat REE pattern similar to the basic schist of the Sanbagawa belt. The basic layer in the boundary zone and epidote–amphibolite have composite–zoned garnet, showing a compositional discontinuity between the core and mantle parts, similar to that in the Sanbagawa eclogite unit. Garnet in the amphibole–rich and mica–rich bands of the alternating layers and pelitic schist shows simple normal zoning, which commonly occurs in the Sanbagawa non–eclogite unit. Sodic plagioclase occurs as inclusions in the mantle part of the composite–zoned garnet and normally zoned garnet as well as in a matrix phase. These lithologies belong to the oligoclase–biotite zone with equilibrium pressure/temperature conditions of 1.1–1.2 GPa/595–625 °C; discontinuity of metamorphic grade is not detected throughout the outcrop for the epidote–amphibolite facies stage. These data suggest that (1) the basic layer is the fractured part of the epidote–amphibolite and (2) the tectonic boundary between the eclogite and non–eclogite units corresponds to the lithologic boundary between the basic layer and alternating layers of thin amphibole–rich and mica–rich bands in the boundary zone.

著者

Masami KANZAKI

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.200611, (Released:2020-12-01)

被引用文献数

2

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CO2 distribution in M12 and M14 cages of CO2–rich melanophlogite from Fortunillo, Tuscany, Italy was studied using synchrotron powder X–ray diffraction. Original and two heat–treated samples at 500 and 1000 °C were studied at room temperature. The diffraction patterns of these samples can be indexed as a cubic cell (Pm3n). For the non–heated sample, CO2 occupancy for M14 cage is close to unity, whereas about 0.85 for M12 cage. For the 500 °C–heated sample, the occupancies for M14 and M12 cages are reduced to 0.79 and 0.57, respectively. Present study showed that CO2 has preference to M14 cage, but substantial CO2 occupies M12 cage. The electron distributions obtained by MEM analysis clearly reveal orientationally ordered CO2 distribution in M12 and M14 cages. Present result is also used to clarify a recently proposed interpretation for the splitting of CO2 Raman vibrational peak for the heat–treated melanophlogite.