著者

Taro KIDO Masanori KUROSAWA Kei IKEHATA

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.220910, (Released:2023-02-10)

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Hydrocarbon fluid inclusions in authigenic quartz from the Jurassic Torinosu Limestone and associated sediment at Sakawa town, Japan, were studied by microthermometry, ultraviolet (UV) fluorescence, and Raman spectroscopy. The quartz contained abundant liquid hydrocarbon and subordinate vapor hydrocarbon fluid inclusions, and tiny solid inclusions of bitumen, calcite, and rarely pyrite. Aqueous fluid inclusions and aqueous components in hydrocarbon inclusions were absent. Under UV irradiation, most of the liquid inclusions from the limestone and associated sediment displayed intense whitish-blue and deep-blue luminescence, respectively. Further, these liquid inclusions were homogenized at around 24 °C and 53 °C, respectively. Small numbers of liquid inclusions from the associated sediments contained a liquefied gas-condensate. Raman measurements indicated the presence of aromatic compounds and the absence of H2O or CO2 molecules in the liquid and vapor inclusions.

著者

Yuzuki SHINJI Tatsuki TSUJIMORI

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.26-32, 2019 (Released:2019-03-08)

参考文献数

40

被引用文献数

7 8

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Retrograde pumpellyite was newly found in garnet blueschist that is Mg–rich equivalent of late Paleozoic retrograde eclogite of the Yunotani Valley in the Omi area, Hida–Gaien Belt. The pumpellyite with high Al/(Al + Mg + Fe) occurs in pressure shadows around garnets; it is associated with secondary glaucophane, epidote, chlorite, titanite, phengite, albite, and quartz, which all characterize a retrograde blueschist–facies mineral assemblage after peak eclogite–facies mineral assemblage. This feature is comparable with retrograde pumpellyite in late Paleozoic garnet blueschist (with relict eclogite–facies mineral assemblage) in the Osayama area of the Chugoku Mountains. Equilibrium phase calculation confirmed that the pumpellyite is stable at a low temperature and pressure portion of the lawsonite–blueschist–facies. T–bulk–composition (Mg) pseudosection suggests that pumpellyite appears preferentially in high Mg/(Mg + Fe) bulk composition. The limited occurrence of retrograde pumpellyite in the Yunotani garnet blueschist and retrograde eclogite would be explained by Mg–rich bulk compositions. Also, the limited occurrence in pressure shadows around garnets suggests that the fluid trapped in the pressure shadows might have enhanced growth (or precipitation) of pumpellyite. This finding provides a strong evidence that the deeply subducted (eclogite–facies) metabasaltic rocks both in the Hida–Gaien Belt and the Chugoku Mountains were subjected to a very similar blueschist–facies overprinting locally reached the pumpellyite stability field. The ‘Franciscan–type’ cooling path suggests a ‘steady–state’ underflow of the paleo–Pacific oceanic plate in late Paleozoic at a convergent margin of the South China Craton.

著者

Sota NIKI Kenta YOSHIDA Hikaru SAWADA Ryosuke OYANAGI 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

vol.117, no.1, pp.210814, 2022 (Released:2022-05-18)

参考文献数

24

被引用文献数

1

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Here we first report the in situ U–Pb dating of metamorphic grossular garnet (Grs) with distinction between internal zonation textures. The studied Grs occurs in an eclogite–facies marble collected from the eastern Iratsu body of the Sanbagawa metamorphic terrane, Japan. The Grs has a patchy texture, predominantly with pure Grs cores and andradite (Adr)–rich rims formed during eclogite–facies and exhumation stages, respectively. The U–Pb ages for the Grs core and Adr–rich rim were 97 ± 10 and 106 ± 16 Ma (95% confidence level), respectively. Despite the compositional zoning formed under different P–T conditions, the U–Pb ages of the core and rim were in similar values within analytical uncertainties. This decoupling of chemical zonation and U–Pb ages implies that the U–Pb chronological signatures of rims were inherited from cores owing to the redistribution of radiogenic Pb in cores during the rim formation through fluid–mediated dissolution and reprecipitation. The Grs U–Pb age (97 ± 10 Ma) thus directly corresponds to previously reported P–T conditions of the core formation during the eclogite–facies metamorphism. This advantage of Grt petrochronology as the combination of radiometric ages obtained by in situ analysis and P–T conditions deduced from paragenesis can contribute to reconstruct reliable metamorphic histories.

著者

Kenta YOSHIDA Sota NIKI Hikaru SAWADA Ryosuke OYANAGI

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.200730, (Released:2020-12-08)

被引用文献数

2

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Datolite [CaBSiO4(OH)] was discovered in an eclogite–facies calcite marble collected from the Eastern Iratsu body in the Sanbagawa metamorphic belt of central Shikoku. The marble was composed of calcite, diopside, and garnet that contained inclusions of omphacite. Enclosed in the marble is a pod composed mainly of quartz, with subordinate calcite, diopside, and garnet that has inclusions of datolite. The formation conditions of the datolite were estimated on the basis of mineral assemblage and the Raman elastic geobarometer to be approximately 400–650 °C and 0.8–1.3 GPa, which coincide with the conditions of the eclogite juxtaposition with the non–eclogite units in the Besshi district. Our study records the highest pressure–temperature conditions as the metamorphic datolite formation. Our findings provide evidence for the occurrence of B–rich fluid infiltration during the juxtaposition of eclogite unit with the non–eclogite unit in the Besshi district.

著者

Atsushi Ishihara Hiroaki Ohfuji

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.230327, (Released:2023-10-13)

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In this study, we investigated the origin and formation process of zeolitized gastropod fossils in Neogene sediments (Shiote Formation) in Minamisoma, Fukushima, Japan using powder X-ray diffraction, SEM-EDS and micro-Raman spectroscopic analysis. The formation of zeolites was particularly pronounced in the upper chamber, which was not filled with detrital particles, of the gastropod fossils, where tabular crystals of heulandite were observed growing directly from the shell wall. The heulandite crystals are often covered by large euhedral crystals of calcite and occasionally by acicular crystals of mordenite. The formation of zeolite (heulandite) was also observed in the matrix of the host sandstone together with clay minerals (mostly montmorillonite), suggesting that the Shiote Formation experienced moderate metamorphism equivalent to zeolite facies during burial diagenesis. The Si/Al ratio of heulandite was found to decrease gradually from the bottom (∼4.5) to the top (∼3.1) within single crystals across the threshold (4.0) for clinoptilolite/heulandite classification boundary. This may reflect the increase in temperature of the surrounding environment with increase in the burial depth. The extensive growth of zeolites and calcite inside the gastropod fossils indicates that the shell provided semi-closed spaces in which pore fluid could be retained and condensed during diagenesis, thus promoting the crystal growth from the supersaturated solution.

著者

Keisuke MITSU Tetsuo IRIFUNE Hiroaki OHFUJI Akihiro 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

pp.210319, (Released:2021-09-30)

被引用文献数

1

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Attempts to synthesize transparent polycrystalline jadeite have been made by direct conversion from bulk glass at pressures 10–20 GPa and temperatures 900–1300 °C using Kawai–type multianvil apparatus. The grain size of jadeite tends to decrease with increasing pressure, but we failed to synthesize polycrystalline jadeite with grain sizes in nano–regime (<100 nm) and obtained the sample with the smallest average grain size of ~ 240 nm at 20 GPa and 1300 °C for 20 min. Polycrystalline jadeite of the minimum grain size exhibits high optical transparency with a transmittance of ~ 70% for a typical wavelength in the visible region. The highest Vickers hardness (Hv) of 14.2 GPa was observed for the polycrystalline jadeite sample with the minimum grain size of ~240 nm, which is about 7% higher than the hardness (Hv = 13.3 GPa) of the sample with the largest grain size of ~ 390 nm. Further increases in optical transparency and hardness of polycrystalline jadeite would be realized if we get nano–polycrystalline samples by optimizing pressure, temperature, heating duration, etc. of the ultrahigh–pressure synthesis experiment.

著者

南部 松夫 谷田 勝俊 北村 強

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.62, no.6, pp.311-328, 1969-12-05 (Released:2008-08-07)

参考文献数

31

被引用文献数

6 11

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New mineral kôzulite belongs to the alkali amphibole group in which manganese (II) is the predominant cation of the Y-position. The mineral occurs as banded aggregate of short prismatic crystala with the faces of b, m and r up to 3.5×2.0×1.5mm in size, in the bedded magnanese deposit of Tanohata Mine, Iwate Prefecture, Japan, in the highly metamorphosed Jurassic chert-hornfels by the intrusion of granodiorite. Associated minerals are braunite, rhodonite, manganiferou alkali pyroxene, manganiferou alkali amphibole and quartz. Color reddish black to black, streak light purplish brown, luter vitreous, H. 5, G. measured 3.30, calculated 3.36. Cleavage (110) perfect. Optically biaxial negative, ns α=1.685, β=1.717(mean), γ=1.720, 2Vα=34-36°, cΛX=25°. Strongly pleochroic with X yellow-brown, Y reddish brown, Z dark brown, absorption Z〉Y〉X, dispersion very weak, probably r〉v. Chemical analysis gave SiO2 51.38, TiO2 none, Al2O3 1.69, Fe2O3 2.85, FeO none, MnO 27.96, ZnO 0.03, MgO 2.71, CaO 1.12, BaO none, Na2O 8.41, K2O 1.36, H2O (-) 0.06, F 0.08, sum 99.75-O (=F2) 0.03=99.72%, corresponding to (Na2.54 K0.27 Ca0.19)3.00 [(Mn3.69 Mg0.63)4.32 (Fe+30.33Al0.31)0.64]4.96Si8.00O21.78[(OH)2.18F0.04]2.22, as O+OH+F=24. The x-ray powder data showed the mineral to be monoclinic with a0=9.91, b0=18.13, c0=5.28Å, β=104.5° and precession photographs of the same specimens by N. Morimoto, Osaka University, showed it to be monoclinic, space group C2/m, a=9.91±0.02, b=18.11±0.04, c=5.30±0.02Å, β=104.6°±0.1°, Z=2. The strongest x-ray lines are 8.51 (100) (110), (4.52) (10) (040), 3.40 (10) (131), 3.29 (17) (240), 3.15 (67) (310), 2.96 (6) (221), 2.827 (31) (330), 2.748 (8) (331), 2.722 (10) (151), 2.602 (6) (061), 2.545 (6) (202), 2.349 (7) (351), 2.174 (9) (261), 1.908 (7) (510), 1.447 (7) (661). The high-temperature x-ray study and DTA indicate that the mineral breaks down to braunit plus glas at about 950°C. The name is for late Dr. Shukusuke Kôzu (1880-1955), formerly Professor in Tohoku University, Japan who made many contributions to the study of rock forming minerals. Type material is preserved at Tohoku University. The mineral and name were approved before publication by the Commission on New Minerals and Mineral Names, IMA.

著者

Raiki YAMADA Toshiro TAKAHASHI Yasuhiro OGITA

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.118, no.1, pp.221219a, 2023 (Released:2023-11-24)

参考文献数

98

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Oligocene to Miocene volcanic rocks from the Toyama basin of the SW Japan arc, that were formed during back-arc spreading in the Japan Sea, were examined to reveal their petrogenesis and temporal change of arc volcanism during the Japan Sea opening. The arc volcanism in the Toyama basin initiated with rhyolitic pyroclastic flows (Tori Formation) containing hecatolite (moonstone) in 23-22 Ma. Enriched Sr-Nd isotope (SrI = 0.70769-0.70944; NdI = 0.51203-0.51224) suggests that contemporaneous andesitic magma (Kamiwazumi and Matsunagi Formations) mixed or assimilated basement granitoids and gneisses of the Hida belt to generate rhyolitic magma. Subsequently, andesitic volcanism (Iwaine Formation) occurred in 18-17 Ma after magmatic hiatus. Andesitic lavas of the Iwaine Formation are composed of high magnesian andesite (HMA), high-Sr andesite and tholeiitic andesite. HMA has Mg# > 64, high Cr and Ni concentrations, not so high Th/Yb and (La/Sm)N ratios, and slightly enriched Sr-Nd isotope (SrI = 0.70482; NdI = 0.51279). High-Sr andesite has relatively low SiO2 content (<60 wt%), high Sr (>2000 ppm) and K2O contents (3.98 wt% in the maximum), indicating that it is low-SiO2 adakite. These geochemical characteristics suggest that HMA and high-Sr andesite were produced by partial melting of the mantle wedge saturated by H2O derived from slab fluid and metasomatized by slab melt, respectively. Although chemical variation diagrams suggest tholeiitic andesite seems to have been generated from basaltic magma, it has enriched Sr-Nd isotope (SrI = 0.70713-0.70756; NdI = 0.51237-0.51241). Thus, tholeiitic andesite is considered to have been produced by AFC (assimilation and fractional crystallization) after generation of basaltic parental magma. Andesitic magmatism of the Iwaine Formation was followed by rhyolitic magmatism of the Iozen Formation in 17-16 Ma. The petrogenesis of the rhyolite from the Iozen Formation can be explained by low-rate mixing between andesitic magma (Iwaine Formation) and the Hida belt. The petrogeneses of the andesites, especially HMA and high-Sr andesite, are related to slab melting. Because the old and cold Pacific plate was subducting beneath the Toyama basin during the Japan Sea opening, additional heat source such as upwelling of the asthenospheric mantle into the mantle wedge is required. Moreover, back-arc spreading in the Japan Sea was driven by upwelling of the asthenospheric mantle into the mantle wedge.

著者

Risako HATADA Hidemi ISHIBASHI Yukiko SUWA Yusuke SUZUKI Natsumi HOKANISHI Atsushi YASUDA

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.190724, (Released:2020-06-26)

被引用文献数

1

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We conducted textural and chemical analyses of melt inclusions and their host plagioclase crystals in the scoria of the Izu–Omuroyama monogenetic volcano, erupted at ~ 4 ka in the Higashi–Izu monogenetic volcanic field, Japan. The groundmass melt was andesitic with ~ 59–61 wt% SiO2, and it contained abundant microphenocrysts of olivine and plagioclase. In contrast, ~ 59% of the plagioclase–hosted melt inclusions have rhyolitic compositions with ~ 70–75 wt% SiO2. The host plagioclase phenocrysts have cores with An# of 44.7 ± 4.2 [An# = 100Ca/(Ca + Na) in mol] and rims with An# of 68–78, and the calcic rims have compositions similar to the microphenocrysts. The cores of the host plagioclase phenocrysts have FeO* and K2O contents that are in equilibrium with the rhyolitic melt inclusions. Using the plagioclase–melt geohygrometers and assuming temperatures of 790–850 °C, we estimated the H2O contents of the rhyolitic melt inclusions to be ~ 4.4–10.2 wt%, indicating H2O–saturation depths of >4.5 km. Our results suggest that an inhibited reservoir of plagioclase–bearing rhyolitic melt existed beneath the monogenetic volcano at the time of the scoria eruption, which was ~ 800 years earlier than the first rhyolitic eruption in the volcanic field. Plagioclase content in the silicic reservoir is estimated to be less than 35.8%, suggesting the magma was eruptible. Our results demonstrate the potential usefulness of plagioclase–hosted melt inclusions for indicating the existence of such an inhibited silicic magma.

著者

Kazuya SHIMOOKA Satoshi SAITO Kenichiro TANI

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.230224, (Released:2023-07-28)

被引用文献数

1

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We carried out zircon U-Pb dating of the Cretaceous gabbroic and granitic rocks exposed in the Kajishima to determine their magmatic ages. The plutonic rocks in the Kajishima are classified into seven lithologies: Hbl-bearing olivine norite, Type-1 Hbl-bearing troctolite, Type-2 Hbl-bearing troctolite, Type-1 pyroxene hornblende gabbronorite, and Type-2 pyroxene hornblende gabbronorite, massive granodiorite, and deformed granodiorite. The new zircon U-Pb ages are: 90.77 ± 0.99 Ma for the Type-2 Hbl-bearing troctolite, 92.35 ± 0.74 Ma for the Type-1 pyroxene hornblende gabbronorite, 91.33 ± 1.03 Ma for the massive granodiorite, and 84.11 ± 1.12 Ma for the deformed granodiorite. The new zircon U-Pb ages suggest multiple episodes of magmatic intrusion in Kajishima during ∼92 Ma and 84 Ma. Although two gabbroic rocks and a massive granodiorite show similar zircon U-Pb ages, subsequent granitic magmatism is unraveled in Kajishima, which is contrary to previous geological studies that postulated an evolution of all plutonic rocks from a single gabbroic parent magma.

著者

Keiko MORI Tatsuki TSUJIMORI Nelson BONIFACE

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.180713, (Released:2018-12-19)

被引用文献数

6

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We report a newly discovered assemblage of talc–kyanite in an amphibolite from the Isimani Suite of the Paleoproterozoic Usagaran Belt, central Tanzania. The amphibolite is characterized by the mineral assemblage of clinoamphibole, kyanite, talc with minor rutile, quartz, dolomite, and rare barite. The high Fe3+/(Fe3+ + Fe2+) ratio (0.48–0.80) of clinoamphibole and the presence of sulfate (barite) indicate a very–high oxidation state during metamorphism. P–T pseudosection modelling predicts that the studied talc– and kyanite–bearing amphibolites formed at high–pressure conditions (P > 1.0 GPa). Moreover, the modelling suggests formation of talc + kyanite + clinoamphibole at a highly oxidizing condition with CO2 fluid. This talc–kyanite association provides an index of high–pressure metamorphism of the Usagaran Belt and marks the oldest record of the talc–kyanite association in regional metamorphism in the Earth’s history.

著者

Nobuhide MURAKAMI Toshio KATO Yasunori MIÚRA Fumitoshi HIROWATARI

出版者

Japan Association of Mineralogical Sciences

雑誌

Mineralogical Journal (ISSN:05442540)

巻号頁・発行日

vol.8, no.2, pp.110-121, 1976 (Released:2007-03-31)

参考文献数

18

被引用文献数

5 18

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Sugilite occurs as an essential mineral amounting to 3–8 percent by volume in aegirine syenite from Iwagi Islet, Ehime Prefecture. It is associated with albite, aegirine, pectolite and a Ca-K-Ti silicate (a still to be identified mineral). Sugilite is light brownish yellow, luster vitreous, streak white. Symmetry hexagonal. Cleavage 0001 weak. Hardness 6–61/2. Specific gravity 2.802 (calc.), 2.74 (meas.).Under the microscope, it is uniaxial negative with ε=1.607, ω=1.610, ω−ε=0.003, and colorless.Estimated chemical composition is SiO2 71.38, TiO2 0.51, A12O3 2.97, Fe2O3 12.76, FeO 0.19, Li2O 3.14, Na2O 4.37, K2O 3.76, H2O(+) 0.81, H2O(−) 0.12, total 100.01%, corresponding ideally to (K, Na)((H2O), Na)2(Fe3+, Na, Ti, Fe2+)2(Li, Al, Fe3+)3(Si12O30) with Z=2.The unit cell dimensions are a0=10.007(2), c0=14.000(2)Å. Space group D26h−P6⁄mcc. X-ray powder data resemble those for sodgianite, milarite, osumilite, merrihueite, roedderite and brannockite.It is clear from the above-cited data that sugilite has milarite-type structure and resembles sodgianite and brannockite in containing lithium in tetrahedral site, but it is distinguished by a high content of ferric iron in 6-coordination.The name is given in honour of the late Professor Ken-ichi Sugi (1901-1948), who first found the occurrence of this mineral with Mr. M. Kutsuna.

著者

平島 崇男

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.78, no.3, pp.77-83, 1983-03-05 (Released:2008-08-07)

参考文献数

13

被引用文献数

11 15

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関東山地において,ひすい輝石+石英組合せを持つ岩石を新たに発見した。この岩石は第三紀の栃谷層と断層関係にある超塩基性岩とともに露出している。この岩石は,ひすい輝石+石英組合せが安定な変成作用(高圧条件)と,アルバイト+エジル輝石が安定な変成作用(中圧条件)の2回の温度圧力条件を記録している。

著者

DAISUKE NISHIO–HAMANE TAKESHI YAJIMA ISSEI IKARI YOSHIYA OHKI HIROFUMI HORI YOSHIHIRO OHARA

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.230605, (Released:2023-09-07)

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Kiryuite and gunmaite were found as new minerals from Tsukubara, Kiryu City, Gunma Prefecture, Japan. Kiryuite is a Mn-rich analogue of viitaniemiite with an ideal formula of NaMnAl(PO4)F3 that mainly occurs as a white powder in cracks in triplite aggregate, and occasionally forms porous plate-like aggregates up to 5 mm in size, while the grains are several micrometers in size. In most cases, the aggregates are also accompanied by small amounts of other minerals such as goyazite, gorceixite, and fluorite. Kiryuite shows white streaks with a vitreous luster, and its Mohs hardness is estimated to be 5 by analogy with viitaniemiite. The calculated density is 3.32 g·cm-3 based on the empirical formula and unit cell volume refined from powder X-ray diffraction (XRD) data. The empirical formula for kiryuite calculated on the basis of O = 4 and F + OH = 3 is Na0.97(Mn0.56Ca0.38Fe0.04Mg0.02)Σ1.00Al0.98P1.02O4(F2.29OH0.71)Σ3. Kiryuite is monoclinic (P21/m) with a = 5.425(4) Å, b = 7.128(4) Å, c = 6.817(6) Å, β = 109.41(7)°, and V = 248.7(3) Å3 (Z = 2). The parameters [d in Å (I/I0) hkl] for the six strongest lines associated with kiryuite in the powder XRD pattern are 3.123 (57) 002, 2.923 (53) 012 and 120, 2.877 (100) 121, 2.560 (27) 200, 2.263 (43) 103, and 2.155 (76) 221. Gunmaite is a new alunite-related mineral with a new structure type that has an ideal formula of (Na2Sr)Sr2Al10(PO4)4F14(OH)12. Gunmaite mainly occurs as a core in hexagonal tablet crystals that coexist with gorceixite and goyazite-like minerals. Gunmaite is colorless and transparent with a greasy to resinous luster and is non-fluorescent. As a bulk crystal including gunmaite, the Mohs hardness is 5, cleavage is perfect on {001} planes, and the tenacity is brittle. The calculated density based on the empirical formula is 3.38 g·cm-3 using the empirical formula and single-crystal XRD data. The empirical formula for gunmaite calculated on the basis of O = 16 and F + OH = 26 is (Na1.72Sr0.70Mg0.56Ca0.01)Σ2.99(Sr1.32Ba0.68)Σ2(Al9.82Mg0.18)Σ10P3.99O16F16.21(OH)9.79. Gunmaite is trigonal (R3m) with a = 6.9972(2) Å, c = 50.270(2) Å, and V = 2131.51(13) Å3 (Z = 3). The structure consists of two PO4, AlO2(OH)4, AlF6, AlOF3(OH)2, SrO6(OH)6, and NaF8 polyhedra. Kiryuite and gunmaite are products of the final stage of hydrothermal activity in association with greisenization.

著者

高木 哲一

出版者

Japan Association of Mineralogical Sciences

雑誌

岩鉱 (ISSN:09149783)

巻号頁・発行日

vol.88, no.4, pp.165-178, 1993-04-05 (Released:2008-03-18)

参考文献数

66

被引用文献数

5 4

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This paper describes the petrography of magnetite-series and ilmenite-series granitoids in the San'yo and San'in belts, and estimates the redox paths of the granitoid magmas during cooling. In magnetite-series granitoids in these areas, the magnetite commonly occurs as secondary minerals after decomposition of magmatic mafic silicates such as pyroxenes, hornblende and biotite. The magnetite is divided into two types, differentiated by their coexisting minerals. The first-type of magnetite crystallizes concurrently with hornblende and biotie after decomposition of pyroxenes and brown hornblende at the late magmatic stage, and continues to crystallize during subsolidus conditions. The second-type of magnetite crystallizes with actinolite, cummingtonite and chlorite during subsolidus stages of crystallization. Petrography, combined with Fe-Ti oxide geothermo-barometers for the magnetite-series granitoids, suggests that the magnetite crystallizes due to an increase in the oxidation state of the magma (and/or fluid phase) above the NNO-buffer during cooling. However, the redox states of the ilmenite-series granitoid magmas are kept below the FMQ-buffer, throughout the solidifying process of the magma. The chemistry of the fluid phase determines whether the magma follows the magnetite-series or ilmenite-series trend.

著者

Yasuhiro TAKAI Seiichiro UEHARA

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.2, pp.110-113, 2012 (Released:2012-05-03)

参考文献数

7

被引用文献数

3 5

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Rhabdophane-(Y), ideal formulaYPO4·H2O, occurs in a druse of the Higashimatsuura basalt at Hinodematsu, Genkai-cho, Saga Prefecture, Japan. It occurs as short rod-like crystals and forms radial aggregates. Rhabdophane-(Y) is hexagonal, P6222, a = 6.959(2) Å, c = 6.384(2) Å, V = 267.7(1) Å3, Z = 3. It is yellowish white to yellowish brown in color with a silky to dull luster. The density is 4.54 g/cm3 (calc.). The strongest lines in the X-ray powder diffraction pattern are [d (I/I0) hkl] 2.821 (100) 102, 3.013 (77) 200, 6.026 (76) 100, 4.385 (47) 101, 3.480 (44) 110, 2.127 (28) 003, and 1.854 (26) 212.

著者

Shumpei YOSHIMURA

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.118, no.1, pp.221224a, 2023 (Released:2023-11-09)

参考文献数

39

被引用文献数

1

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H2O-CO2-dominated fluids play a crucial role in most geological phenomena involving fluid-mineral-melt interactions. The equation of state is an essential tool for understanding the phenomena because it predicts the thermodynamic properties of the fluids. The modified Lee-Kesler equation of state for H2O-CO2 mixture fluid developed by Duan and Zhang (2006) is the most accurate at present and is applicable to a wide pressure-temperature range (∼ 2573 K and ∼ 10 GPa). Because of its high accuracy and wide applicable range, the equation has been used for constructing solubility laws in silicate melts. In this paper I review the Duan and Zhang (2006) equation of state and present the calculation procedure. Because the equation for calculating the partial fugacity coefficient is erroneously presented in the original paper, the correct equation is provided here. A C-language code and a Windows executable program for computing thermodynamic properties are provided for the convenience of users. The influence of the nonideal behaviour of the H2O-CO2 mixture fluid on some geological situations is discussed.

著者

Daisuke NISHIO–HAMANE Katsuyuki SAITO

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.220309, 2022 (Released:2022-09-08)

参考文献数

38

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Mineralogical investigation of platinum–group minerals (PGM) from the placer deposit in northwestern Hokkaido, Japan, was conducted at six rivers and two coasts covering an area of 70 km north–south and 30 km east–west: the Moshosanbetsu River (M), the Shosanbetsu River (S), the Ainusawa River (A), the Tomamae coast (T), the Obira coast (OC), the Kamikinenbetsusawa River (K), the Obirashibe River (OR), and the Numatapon River (N) from north to south. Details of the major PGM grain and the occurrence of small but diverse PGM inclusions were revealed in this study. Among diverse PGM inclusions, Cu3Pt mineral was discovered in PGM placer from the coast of Tomamae town, and it has been approved as a new mineral, tomamaeite, named after the type locality, by the International Mineralogical Association, the Commission on New Minerals, Nomenclature and Classification (IMA–CNMNC). Later, tomamaeite was also discovered in five localities. Tomamaeite occurs in Pt–Fe(Cu) alloys such as tulameenite, ferronickelplatinum, tetraferroplatinum, and hongshiite as an anhedral particle with a size of less than 20 µm. Tomamaeite is an opaque mineral and has metallic luster with a pale mist white color in reflected light. The hardness of tomamaeite has yet to be determined, although it is estimated to be ~ 3½ from comparison with compositionally related minerals and the calculated density is 12.4 g·cm−3 using the empirical formula and powder X–ray diffraction data. The empirical formula of tomamaeite calculated on the basis of 4 apfu is (Cu3.01Fe0.06Ni0.01)Σ3.08(Pt0.90Ru0.01Rh<0.01Pd<0.01Os<0.01Ir<0.01)Σ0.93, (Cu2.92Fe0.05Ni0.04)Σ3.01(Pt0.97Pd0.01Rh0.01)Σ0.99, (Cu2.86Sb0.13Fe0.03Ni0.02)Σ3.03(Pt0.92Ir0.02Pd0.01Os0.01)Σ0.97, (Cu2.71Sb0.19Fe0.02Ni0.02)Σ2.94(Pt1.01Ir0.05)Σ1.06, (Cu2.93Fe0.02)Σ2.94(Pt1.04Rh0.01)Σ1.06, and (Cu2.82Fe0.04Ni0.04)Σ2.90(Pt1.07Ir0.03Pd<0.01)Σ1.10 from the Tomamae coast, the Moshosanbetsu River, the Shosanbetsu River, the Ainusawa River, the Kamikinenbetsusawa River, and the Numatapon River, respectively. Crystal chemistry was investigated using tomamaeite from the Tomamae coast. Tomamaeite is cubic, Pm3m, with lattice parameters a = 3.683(2) Å and V = 49.97(7) Å3 (Z = 1) of Cu3Au–type structure, in which Pt occupies the position of origin, and Cu occupies the face–centered positions on a face–centered cubic lattice. PGM from northwestern Hokkaido probably have a mostly common origin and are characterized by depleted ultramafic rocks, and tomamaeite is a non–unique mineral that is formed during the universal post–magmatic process with alteration of such ultramafic rocks to serpentine.

著者

Mariko NAGASHIMA Daisuke NISHIO–HAMANE Shuichi ITO Takahiro TANAKA

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.3, pp.129-139, 2021 (Released:2021-07-17)

参考文献数

23

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Ferriprehnite (IMA2020–057), ideal formula Ca2Fe3+(AlSi3)O10(OH)2, is a new mineral that was found as secondary mineral in druses developed in the hydrothermal altered dolerite from Kouragahana, Shimane Peninsula, Japan. Ferriprehnite is an Fe analogue of prehnite. The crystals consisting of ferriprehnite and prehnite occur as a radial aggregate. The tabular crystals are up to 300 µm long, 100 µm wide, and 50 µm thick. Ferriprehnite is colorless to pale green with white streak and vitreous luster. It has a Mohs hardness of 6½. Its cleavage is good on {100}. The calculated density is 2.97 g/cm3. The empirical formula of ferriprehnite on the basis of 10O + 2OH using the result obtained by electron microprobe analysis is Ca1.99(Fe3+0.66Al0.34)Σ1.00(Al1.02Si2.98)Σ4.00O10(OH)2. Structure refinement converged to R1 = 4.64%. Its space group is orthorhombic Pma2 with unit–cell parameters a = 18.6149(10) Å, b = 5.4882(3) Å, c = 4.6735(3) Å, and V = 477.46(1) Å3. The determined site occupancy at the octahedral M site is Fe0.637(9)Al0.363 indicating that the M site is predominantly occupied by Fe. <M–O> increases with increasing Fe content leading to isotropic expansion of MO6 octahedra. The a– and c– dimensions of ferriprehnite are longer than those of prehnite due to Fe substitution for Al at the M site.

著者

TAKEO WATANABE

出版者

Japan Association of Mineralogical Sciences

雑誌

Mineralogical Journal (ISSN:05442540)

巻号頁・発行日

vol.2, no.6, pp.408-421, 1959 (Released:2008-03-18)

参考文献数

18

被引用文献数

7 10

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The ore deposits of the Noda-Tamagawa mine have become famous for their wealth of mineral species, the production of high grade manganese ores, and also the recent discovery of uranium ores. More than seventy minerals have been found in this mining area including such rare minerals as pyrochroite, manganosite, vredenburgite, yoshimuraite (a new mineral of Ba, Sr, Mn, Ti-silicate), etc. The ore deposits of this mine may be classified into the following types: (A) The contact-metamorphosed bedded manganese deposits in metamorphosed roof pendant in the batholithic mass of granitic rocks. (B) (1) The uranium-bearing veins. (2) The cobalt-nickel-molybdenum-bearing uranium deposits associated with pelitic hornfels. (C) Pyrometasomatic copper-bearing pyrrhotite deposits found in limestone. (D) Gold-silver-bearing quartz-arsenopyrite veins. Among them manganese deposits are economically the most important ones. The geology and ore deposits of the mine are briefly described. The mineral parageneses of ores and country rocks are shown in Tables 1 and 2.