検索結果 13726 件
| JaLCDOI | 10.18926/ESR/13922 |
|---|---|
| フルテキストURL | ESR_4_76.pdf |
| 著者 | 河原 昭| |
| 抄録 | Statistical calculation have been carried out on the volumes of the asymmetric unit of minerals. This treatment is related to the origin of the symmetry and periodicity of the crystals, and to the equilibrium conditions of these crystals. From the view point of the cohesion energy, if the crystals were grown under the condition of nearly perfect equilibrium states, than all the volumes of the asymmetric unit of each crystal structure will be approximately equal, and if the volume of the asymmetric units of a certain mineral is larger than the average value, this mineral is considered to be grown in a metastable condition. The calculation of the cell dimensions of minerals have been carried out by the use of deta from previous investigations. The statistical consideration of the volumes of the asymmetric unit of minerals is considered to be an appropriate criterion to relate the stability of minerals to their descriptive mineralogy. |
| キーワード | geneses of symmetry symmetry periododicity equilibrium |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1997-09-20 |
| 巻 | 4巻 |
| 号 | 1号 |
| 開始ページ | 79 |
| 終了ページ | 96 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310432 |
| JaLCDOI | 10.18926/ESR/13921 |
|---|---|
| フルテキストURL | ESR_4_73.pdf |
| 著者 | 香原 静雄| 河原 昭| |
| 抄録 | The configuration of the Si-O framework in alkali zinc silicates has been investigated on the basis of recently determined structures. The results have shown that there is a linear correlation between the ionic radii of alkali ions and the molar abundance of ZnO+SiO2 per one alkali ion in the structure. This indicates that in the case of zinc silicates, the configuration of the Si-O frameworks is largely influenced by the ionic radii of alkali ions in the structure. On the contrary, in the case of alumino-silicates, the configuration of the Si-O framework is independent of ionic radii of alkali ions. In the former, the Si-O framework is considered to be plastic, while in the latter, it could be called rigid. The latter extreme cases are those of zeolites. In this case, the configuration on frameworks is not entirely influenced by the ionic radii of alkali atoms present. These results are discussed in connection with the historical investigations of silicate structures. |
| キーワード | silicate zinc silicate alumino-silicate framework ionic radii framework configu-ration |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1997-09-20 |
| 巻 | 4巻 |
| 号 | 1号 |
| 開始ページ | 73 |
| 終了ページ | 78 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310344 |
| JaLCDOI | 10.18926/ESR/13919 |
|---|---|
| フルテキストURL | ESR_4_41.pdf |
| 著者 | Okamoto Yasuhiko| |
| 抄録 | Kalsilite, a polymorph of KAISiO4 is an end member of nepheline-kalsilite series and the mineral was syn-thesized by hydorhermal methods. The synthetic kalsilite is hexagonal, P63, with a=5.151(5), c=8.690(8) A. The structure was refined by full-matrix least-squares methods to a R-value 0.084, using 373 observed reflections. The obtained structure agrees well with those of the natural and the alkali-exchanged specimens reported in the previous literatures. The oxygen atoms are disordered at two mirror-equivalent sites, constructing the domain structure. The average domain structure shows P63mc symmetry and the strctural relation between the two P63 structure corresponds to the twinning by merohedry. The domain structure was considered to be caused accompanied with the high-low inversion of the kalslite structure. Heating experiments of kalsilite reveal that the X-ray powder pattern changes at 865℃, and that cell dimensions vary discontinuously at this temperature. It was confirmed that kalsilite underwent a displacive transition like those observed in quartz or tridymite. The high-form is refered as 'high-kalsilite', and a possible simulate model is proposed. The structure of the high-kalsilite at 950℃ was refined byfull-matrix least-squares methods to a R-value 0.095, using 115 observed reflections. The high-kalsilite is also hexagonal, P63mc or P63/mmc, with a=5.288(1), c=8.628(5) A at 950℃. The structure almost prefectly coincides with that of the simulated model. Based on the interatomic distances, the distribution of silicon and aluminum atoms is found to be or-dered and the space group is determined to be P63mc. Kaliophilite and the related orthorhombic from, polymorphs of KAISiO4, were synthesized by dry method. The synthetic kaliophilite (kaliophilite-H2) is hexagonal with a=5.17(1), c=8.49(3) A, and the orthorhombic KAISiO4 (kaliophilite-O1) is orthormbic with a=9.01(1), b=15.60(2), c=8.53(4) A. Detailed examina-tion of the obtained powder patterns together with that of simulated model indicates that the kaliophilite-H2 has a disorderd structure of four types of the low-kalsilite. The structure was refined by the X-ray powder pattern-fitting method (Rietvelt method) to a R-value 0.121. |
| キーワード | kalsilite kaliophilite faldspathoid systheses crystal structre |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1997-09-20 |
| 巻 | 4巻 |
| 号 | 1号 |
| 開始ページ | 41 |
| 終了ページ | 72 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310427 |
| JaLCDOI | 10.18926/ESR/13912 |
|---|---|
| フルテキストURL | ESR_5_17.pdf |
| 著者 | 山本 雅弘| 加瀬 克雄| Harada, Kaori| |
| 抄録 | Sulfur isotope rations of sulfide minerals in the ore specimens from the deposit of the Tsuchikura mine are distrib-uted in a range from -0.8 to 5.4%, mostly from +0.5 to 3.0%, close to the previous data (from +1 to +3%) by Miyake and Sasaki (1980). The distribution range is also similar to the major Besshi-type deposites of the Sambagawa terrain. Sulfur isotope fractionation between coexisting pyrite and chalcopyrite is not uniform. This may be largely due to spatial tearrangament of the initial orebodies to the present form. Sulfide minerals mostly pyrite from host rocks (siltsones, sandstones, basaltic rocks) exhibit remarkably low δ34S values ranging from -49.3 to -2.6%, dis-tinctly different from the δ34S values for sulfide minerals of ores. The low δ34S values may indicate the bacteriogenic origin of host rock sulfides, although it seems peculiar that basaltic rocks also have extremely low δ34S values. |
| キーワード | Sulfur isotope ratio Besshi-type deposit Tsuchikura mine Pyrite Chalcopyrite |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1998-09-20 |
| 巻 | 5巻 |
| 号 | 1号 |
| 開始ページ | 17 |
| 終了ページ | 22 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310378 |
| JaLCDOI | 10.18926/ESR/13908 |
|---|---|
| フルテキストURL | ESR_6_39.pdf |
| 著者 | Yamamoto Masahiro| Ichimoto Hideo| Komatsu Shinji| Yamashita Ruka| |
| 抄録 | Hydrogen and oxygen isotope rations of thermal waters from 46 spas in Okayama Prefecture range from -62.6 to -29.2% in δD and from -10.0 to -4.4% in δ18O, respectively. The isotope rations indicate that all but one of the thermal water in Okayama prefecture are meteoric in origin. The Ofuku thermal water is the only exception, which is probably a mixture of seawater and meteoric water with the ratio of about 1. Sulfur isotope rations of dissolvel sulfate in the thermal waters range from -6.2 ti 59.3% in δ34S. The high δ34S values observed in some thermal waters may be due to bacterial reduction of sulfate. |
| キーワード | Hydrogen isotope ratio Oxygen isotope ratio Sulfur isotope ratio Thermal water Spa Okayama |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1999-09-20 |
| 巻 | 6巻 |
| 号 | 1号 |
| 開始ページ | 39 |
| 終了ページ | 44 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310408 |
| JaLCDOI | 10.18926/ESR/13904 |
|---|---|
| フルテキストURL | ESR_6_1.pdf |
| 著者 | 井上 佳紀| 加瀬 克雄| |
| 抄録 | Phlogopite and hornblende were found in amall amounts in the contact-metamorphosed dunite-harzburgite complex at Yanomine. Phlogopite occurs in interstices of silicate minerals in dunite and harzburgite located near the contact with granite. Some phlogopite grains also occur as inclusions in chromian spinel of chromitite bands. Hornblende is present associated with such metamorphic minerals as talc, olivine and orthopyroxene. Interstitial phlogopite is characterized by lower TiO2 and higher K/(K+Na) atomic ratio compared to that included in chromian spined. Hornblende in dunite chages its composition from edenite associated with olivine-talc through edenitic hornblende to Si-poorer magnesio-hastingsitic hornblende and magnesio-hastingsite with olivine or olivine-orhtopyroxene. The interstitial phlogopite is suggested to have been formed intimately connected with fluids generated in ralation to the intrusion of granite. On the other hand, included phlogopite is considered to have crystallized from the incompatible elements-enriched hydrous melt resulted from mantle-melt interaction. Hornblende should be a metamorphic mineral formed under high temperature conditions. |
| キーワード | Phlogopite Hornblende Ultramafic complex Dunite Harzburgite Chromitite Contact metamor-phism Yanomine |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1999-09-20 |
| 巻 | 6巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 12 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310269 |
| JaLCDOI | 10.18926/ESR/13902 |
|---|---|
| フルテキストURL | ESR_7_47.pdf |
| 著者 | Yamagiwa Nobuo| 鈴木 茂之| Okimura Yuji| |
| 抄録 | A new rugose coral species, Lithostrotion (Siphonodendron) hinensis is described in this paper. It was collected from the Carboniferous Hina limestone in Okayama Prefecture, Southwest Japan. Judging from the paleontological data, the age indicates probably Late Viaean, Early Carboniferous. |
| キーワード | Early Carboniferous rugosa Lithostrotion (Siphonodendron) Hina Limestone Okayama |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2000-09-20 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 47 |
| 終了ページ | 50 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310319 |
| JaLCDOI | 10.18926/ESR/13899 |
|---|---|
| フルテキストURL | ESR_7_27.pdf |
| 著者 | 逸見 千代子| 草地 功| Kagetama Tatsuya| |
| 抄録 | The clinopyroxenes of the hybrid rocks from the Hirata outcrop, Kushiro, Hiroshima Prefecture, Japan are grouped into(1)diopside, (2)aegirine, and (3)zoned pyroxene. The diopside occurs as isolated crystals enclosed in feldspars. The aegirine occurs along with late hydrous minerals in pore spaces. The zoned pyroxenes occur as discrete cryatals with wide rims growing interstitially between feldspar laths and show a continuous composition-al trend from diopside through hedenbergite and aegirine-augite to aegirine or titanian aegirine. The pyroxenes enclosed in feldspars and the cores of the zoned crystals have nearly same chemical composition. The late stage pyroxenes are characterized by extreme enrichment of sodium and sometimes titanium. The titanian aegirines studied hera are characterized by the predominance of the Na(Fe2+, Mg)0.5Ti0.5Si2O6 component over other Ti-bearing pyroxene components. The compositional trend of clinopyroxenes from the Hirata hybrid rocks follows a typical trend of peralkalne rocks. The peralkaline neture of the Hirata samples is a result of compositional change of magma accompanied by the metasomatic skarn formation. |
| キーワード | aegirine aegirine-augite diopside pyroxene hybrid rock skarn |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2000-09-20 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 27 |
| 終了ページ | 34 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310313 |
| JaLCDOI | 10.18926/ESR/13893 |
|---|---|
| フルテキストURL | ESR_7_15.pdf |
| 著者 | 小田 仁| Ito Aki| |
| 抄録 | Long-period coda waves were recorded on the vertical-component seismograms of aftershocks of the Hyogo-ken Nanbu earthquake, 1995. We identify the long-period coda waves as Rayleigh wave, because they appear after the S-arrival times and exhibit the normal dispersion that propagation velocity of the coda waves increases with an increase in period. By applying the moving window analysis to the coda waves from nine aftershocks, the group velocities are determined as a function of period within the range of 2 to 8 s. The group velocity dispersion data are inverted to investigate the S-wave velocity structure of the upper crust. The S-wave velocity structure is consistent with those obtained in previous studies using traval time analysis of bood waves. |
| キーワード | surface wave dispersion coda wave S-wave velocity structure upper crust Hyogo-ken |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2000-09-20 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 15 |
| 終了ページ | 18 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310493 |
| JaLCDOI | 10.18926/ESR/13889 |
|---|---|
| フルテキストURL | ESR_8_1_39.pdf |
| 著者 | 小林 大樹| Yamamoto Masahiro| |
| 抄録 | Hydrogen and oxygen isotope ratios of thermal waters from 42 hot springs in Izu Peninsula, Shizuoka Prefecture, range from -51.7 to -24.7% in δD and from -7.9 to -4.1% in δ18O, respectively. The isotope ratios suggest that most of the thermal waters in Izu Peninsula are essentially meteoric in origin. Significantly deviated from the normal meteoric waters are thermal waters from Yumigahama, Kumomi, and Shimogamo hot springs which may be mixtures of seawater and local meteoric waters, and thermal waters from Izusan and Imaihama whose oxygen isotope ratios may have become heavier by water-rock interaction. |
| キーワード | Hydrogen isotope ratio Oxygen isotope ratio Thermal water Hot spring Izu Peninsula Shizuoka Prefecture |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2001-09-20 |
| 巻 | 8巻 |
| 号 | 1号 |
| 開始ページ | 39 |
| 終了ページ | 44 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310513 |
| 著者 | Saieev K| 小山内 康人| |
|---|---|
| 発行日 | 2002-09-20 |
| 出版物タイトル | Okayama University Earth Science Report |
| 巻 | 9巻 |
| 号 | 1号 |
| 資料タイプ | 紀要論文 |
| JaLCDOI | 10.18926/ESR/13873 |
|---|---|
| フルテキストURL | earth_science_reports_010_1_11.pdf |
| 著者 | 鈴木 功| 井上 靖| 小田 仁| 森岡 正名| |
| 抄録 | Resonant frequencies for a single crystad diopside sphere are measured accurately and rhirteen elastic moduli are reluced by the least squares calculation, A set of mduli gives theoretical resonant frequencies close enough to the observed ones. |
| キーワード | diopside single crystal resonace sphere elasticity |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2003-12-20 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 11 |
| 終了ページ | 14 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310552 |
| JaLCDOI | 10.18926/ESR/13871 |
|---|---|
| フルテキストURL | earth_science_reports_010_1_1.pdf |
| 著者 | 冨谷 尚士| 井上 佳紀| 加瀬 克雄| |
| 抄録 | In order to know the reason why the Cu/Zn-Pb ratios of skarn-type deposits related with the ilmenite-series granitic rocks are markedly higher than those related with the magnetite-series, comparative mineralogical studies were carried out for the two types of granitic rocks in the Chugoku district. An attention was focused on the be-havior of Zn during the crystallization of granitic magma, because Zn contents of mafic minerals can be obtained by non-destructive electron microprobe analyses. Microscopic observation indicats that no sphalerite occurs in the magnetite-series granitic rocks, which im-plies that the magmas corresponding to the granitic rocks were undersaturated in respect to ZnS. Electron micro-probe analyses revealed that the Fe/(Fe+Mg) ratios of mafic minerals such as biotite and hornblende in the ilmen-ite-series granitic rocks are remarkably higher than those in the magnetite-series, and the Zn contents are posi-tively correlated with the Fe/(Fe+Mg) ratios in the ilmenite-series granitic rocks. Also the Zn/Fe rations seem to be slightly higher in the ilmenite-series granitic rocks. In contrast, the correlation between Zn contents and Fe/(Fe+Mg) ratios is ambiguous in magnetite-series granitic rocks. With a progress of crystallization differentiation, therefore, Zn may be removed more effectively in the il-menite-series granitic magma, and the contents may be growing scarce in the fractionated ilmenite-series granitic magma. On the other hand, magnetite-series granitic magma probably increases the Zn-contents in the advanced stage of the crystallization. The hydrothermal fluids genetically related to the fractionated magnetite-series grani-tic magma are likely to be enriched in Zn, being favorable for the formation of Zn-rich deposits. |
| キーワード | Magnetite-series Ilmentie-series Granitic rocks Zn contents Mafic minerals Ore deposit |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2003-12-20 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 10 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310429 |
| JaLCDOI | 10.18926/ESR/13862 |
|---|---|
| タイトル（別表記） | β-, γ-相(Mg,Fe)2SiO4の弾性率の温度変化 : 補遺 |
| フルテキストURL | earth_science_reports_011_1_7.pdf |
| 著者 | 間山 憲仁| 鈴木 功| |
| 抄録 | We measured the resonant frequencies for sphere specimens of the high pressure phases, β-and γ-(Mg0.91Fe0.09)2SiO4 from 298 to 470 K. The adibatic bulk modulus Ks and shear modulus μ at 298 K were determined to be Ks=165.72(6), μ=105.43(2) GPa for the β-phase, and Ks=185.1(2), μ=118.22(6) GPa for the γ-phase, respectively. The average slopes of the moduli at the measured temperature ranges were found to be ∂Ks/∂T=-0.175(3), ∂μ/∂T=-0.0159(1) GPaK-1 for the β-phase and ∂Ks/∂T=-0.193(6), ∂μ/∂T=-0.148(3) GPaK-1 for the γ-phase. The numerals in parentheses indicate probeble errors in the last place. In this technical report, we describe the observed frequencies and calcuation method to obtain elastic moduli, in details. |
| キーワード | Wadsleyite Ringwoodite Elastic moduli |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2004-12-31 |
| 巻 | 11巻 |
| 号 | 1号 |
| 開始ページ | 7 |
| 終了ページ | 14 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310650 |
| JaLCDOI | 10.18926/ESR/13861 |
|---|---|
| タイトル（別表記） | 重力異常データのカラムインバージョンから見積もったモホ不連続面の形状 |
| フルテキストURL | earth_science_reports_011_1_1.pdf |
| 著者 | 福永 真理子| 小田 仁| 志知 竜一| |
| 抄録 | We present an inversion method, called "column inversion", to retrieve two-dimensional variation of the depth to the Moho discontinuity from Bouguer gravity anomaly data, assuming that a density jump between the lower crust and upper mantle is regionally invariant. The inversion method is applied to reveal the apatial undulation of the Moho discontinuity in the Chugoku and Shikoku districts, southwest Japan. The result shows that the Moho is deep in the land area and shallow in the sea area. The Moho is anomalously deep in the west regions of Shikoku and Chugoku districts, where the prominent negative gravity anomaly is observed. The two-dimensional variation of the Moho depth is quite similar to that determined by inversion of the first P-arrival time data. The column inversion of the Bouguer gravity anomaly data is proved to be useful for determining the fine structure of the Moho discontinuity undulation. |
| キーワード | Bouguer Gravity Anomaly Column Inversion Moho Discontinuity Chugoku and Shikoku Districts |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2004-12-31 |
| 巻 | 11巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 5 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310563 |
| JaLCDOI | 10.18926/ESR/13855 |
|---|---|
| タイトル（別表記） | 中国淮河流域付近の入梅前の時期における大気場や陸面状態の季節進行 (1998年の事例解析) |
| フルテキストURL | ESR_12_31.pdf |
| 著者 | 池田 祥一郎| 加藤 内藏進| 塚本 修| |
| 抄録 | Seasonal evolution of atmospheric and land surface conditions around the Huaihe River Basin in China in the pre-Meiyu stage of 1998 were examined, mainly based on the GAME re-analysis data. Around the Huaihe River Basin in China (just to the nront of the Changjiang River Basin), although the air temperature increased rapidly already in early June (the Meuyu front was located to the south of that region), the specific humidity did not increas so much at time. In addition, the latent heat supplied from the ground there decreased from late May to early June, compared to that before early May. The time mean southerly wind component across the low-level baroclinic Zone (although not so strong as in the mature stage of the Meiyu) invaded into Central Cjina during late April to early May. On the other hand, the relatively strong wind region once retreated southward in the middle of May associated with the onset of the Southeast Asian monsoon, and the calm wind region with frequent appearance of the surface high was seen around the Huaihe River Basin from late May to early June. Thus the present study shows that the Huaihe River Basin once experiences the rather drier stage just before the onset stage of the mature Meiyu there. |
| キーワード | arid region in China and the Meiyu front seasonal evlution in East Asia Land surface condition around the Meiyu front |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2005-12-31 |
| 巻 | 12巻 |
| 号 | 1号 |
| 開始ページ | 31 |
| 終了ページ | 37 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310602 |
| JaLCDOI | 10.18926/ESR/13851 |
|---|---|
| タイトル（別表記） | ガーナ, ビルム・ダイヤモンド産地のアクァティア地域に分布する沖積層の重鉱物分析 |
| フルテキストURL | ESR_12_7.pdf |
| 著者 | Samuel Dampare| Daniel Asiedu| Bruce Banoeng-yakubo| 柴田 次夫| |
| 抄録 | Heavy mineral analysis was carried out on Pliocene to Recent alluvial sediments from the Birim diamondiferous field od Ghana. The main objective of the study was to examine the mineral composition of heavy fractions in order to identify : (1) the heavy mineral assenblage that occur in the sediments, (2) particular diamond indicator minerals associated with the diamonds, and (3) the provenance of the alluvial sediments. The heavy minerals are essentially composed of staurolite, ilmenite and magnetite in varying proportions, with trace amounts of leucoxene, rutile, garnet and zircon. The heavy mineral assenblage and chemical composition of ilmenite and gamet suggest their derivation from phyllites and schists which reflect directly the composition of the basement rocks developed in the study area. The absence of diamond indicatior minerals such as apatite, pyrope garmet, chromian spinel, and picroilmenite in the heavy fraction is unlikely to be due to their destruction during intense weathering and/or diagenesis but rarher their non-occurrence in the area. |
| キーワード | Heavy minerals provenance sediments diamonds Ghana |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2005-12-31 |
| 巻 | 12巻 |
| 号 | 1号 |
| 開始ページ | 7 |
| 終了ページ | 14 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310657 |
| JaLCDOI | 10.18926/ESR/13850 |
|---|---|
| タイトル（別表記） | 沖縄トラフ第四与那国海丘海底熱水系チムニーの錫を含む黄銅鉱と白金を含む輝蒼鉛鉱 |
| フルテキストURL | ESR_12_1.pdf |
| 著者 | Gena, Kaul| 千葉 仁| 加瀬 克雄| |
| 抄録 | The active sulfide chimney ore sampled from the flank of the active Tiger chimney in the Yonaguni Knoll IV hydrothermal system, South Okinawa Trough, consists of anhydrite, pyrite, shalerite, galena, chalcopyrite and bismuthinite. Electron microprobe analyses indicated that the chalcopyrite and bismuthinite contain up to 2.4 wt. % Sn and 1.7 wt. % Pt, respectively. The high Sn-bearing chalcopyrite and Pt-bearing bismuthinite are the first occurrence of such minerals on the submarine hydrothermal systems so far reported. The results confirm that the Sn enters the chalcopyrite as a solid solution towards stannite by the coupled substitution of Sn 4+ Fe 2+ for Fe 3+ Fe 3+ while Pt enters the bismuthinite structure as a solid solution during rapid growth. The homogenization temperature of the fluid inclusions in anhydrite (220-310℃) and metasured end-member temperature of the vent fluids (325℃) indicate that the minerals are precipitated as metastable phases at temperature around 300℃. The Sn-bearing chalcopyrite and Pt-bearing bismuthinite expess the original composition of the minerals deposited from a hydrothermal fluid with temperatures of about 300℃. |
| キーワード | Sn-bearing chalcopyrite Pt-bearing bismuthinite Active sulfide Chimmey Yonaguni Knoll IV Okinawa Trough seafloor hydrothermal system |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2005-12-31 |
| 巻 | 12巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 5 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310444 |
| フルテキストURL | Ana_Sci_24_505.pdf |
|---|---|
| 著者 | Kunihiko Seno| Kazuki Matsumura| 大島 光子| 本水 昌二| |
| 発行日 | 2008-04-10 |
| 出版物タイトル | Analytical Sciences |
| 巻 | 24巻 |
| 号 | 4号 |
| 出版者 | 日本分析化学会 |
| 開始ページ | 505 |
| 終了ページ | 508 |
| ISSN | 0910-6340 |
| NCID | AA10500785 |
| 資料タイプ | 学術雑誌論文 |
| 言語 | 英語 |
| OAI-PMH Set | 岡山大学 |
| 著作権者 | 日本分析化学会 |
| 論文のバージョン | publisher |
| DOI | 10.2116/analsci.24.505 |
| JaLCDOI | 10.18926/ESR/13844 |
|---|---|
| タイトル（別表記） | バングラディシュの更新世台地の地形と地質 |
| フルテキストURL | EAR_13_1_1.pdf |
| 著者 | Towhida Rashid| Md. hossain Monsur| 鈴木 茂之| |
| 抄録 | With regards to the origin and evolution of the Pleistocene tracts (Lalmai, Madhupur and Barind tracts) of Bangladesh, two trends of thoughts are common. Most of the authors believed that the Madhupur, Barind and Lalmai tracts represent tectonically uplifted surface. Some researchers have different opinion and they believed that the Lalmai hills and the Madhupur locality represent tectonically uplifted blocks but the whole Barind tract and the major portion of the Madhuput tracts are not tectonically uplifted, rather these are originated by erossional-depositional processes. In order to solve the problems associated with origin and evolution of Pleistocene tracts of Bangladesh, further study is needed. Borehole data may be collected and fusion images can be prepared from aerial photographs and setellite images to detect netectonic imprins and geomorphological signatures of the areas. Elaborate laboratory analysis of sediment deposits, radiocarbon dating my indicate a new dimension about the origin and evolution of these tracts. |
| キーワード | Bangladesh Lalmai Hill Barind Tract Madhupur Tract Neotectonices Aerial photographs Satellite Image Fusion Image |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2006-03-31 |
| 巻 | 13巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 13 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | 岡山大学地球科学研究報告編集委員会 |
| 論文のバージョン | publisher |
| NAID | 120002310445 |