検索結果 11005 件
| 著者 | 劉 克約| 森 秀治| 高橋 英夫| 友野 靖子| 和気 秀徳| 菅家 徹| 佐藤 康晴| 平賀 憲人| 足立 尚登| 吉野 正| 西堀 正洋| |
|---|---|
| 発行日 | 2008-12-01 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 120巻 |
| 号 | 3号 |
| 資料タイプ | 学術雑誌論文 |
| 著者 | 末久 弘| 豊岡 伸一| 堀田 勝幸| 内田 亜希子| 宗 淳一| 藤原 義朗| 松尾 恵太郎| 大内田 守| 高田 穣| 木浦 勝行| 伊達 洋至| |
|---|---|
| 発行日 | 2008-12-01 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 120巻 |
| 号 | 3号 |
| 資料タイプ | 学術雑誌論文 |
| 著者 | 和泉 健| |
|---|---|
| 発行日 | 1994 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 106巻 |
| 号 | 3-4号 |
| 資料タイプ | 学術雑誌論文 |
| JaLCDOI | 10.18926/ESR/13957 |
|---|---|
| フルテキストURL | ESR_1_27.pdf |
| 著者 | 岡野 修| 西谷 七代| 加々美 寛雄| |
| 抄録 | Rb-Sr isotopic study as well as petrologic investigations have been done on sixteen individul chondrule samples separated from the Allegan (H5) chondrite. The Rb-Sr chondrule isochron does not define a very precise age (4.42±0.17 Ga) and 87Sr/86Sr initial ratio (0.6997±0.0014) due to the very small variation in Rb/Sr ratio for the chondrules, whereas the model ages give a much more speciffic value (4.42±0.02 Ga). These ages may probably be indicative of the time of primary process (es) (e.g. chondrule formation) rather than secondary (metamorphic reheating) or tertiary (shock heating) processes in and/or on the H-chodrite parent body (or bodies). Chemical compositions of oliveines (Fa=17.5mol%, mean deviation (MD)=1.3%) and orthopyoxenes (Fs=15.4mol%, MD=3.2%) are moderately homogenized among the chondrules, while certains chemically uneguilibrated features are also distinctly preserved in this chondrite. Homogeneity of the mineral compositions, therefore, could not have been caused by thermal metamorphism but were probably inherited from processes prior to aggregation of the components. The overall implications of the chondrule isochron and model ages in relation to the petrological features and in comparison with Rb-Sr data of other chondrites of different chemical groups and petrologic types are discussed. |
| キーワード | chondrule age Rb-Sr isochron Allegan H- chondrite meteorite metamorphism olivine pyroxene |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1994-09-20 |
| 巻 | 1巻 |
| 号 | 1号 |
| 開始ページ | 27 |
| 終了ページ | 36 |
| 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 | 120002310261 |
| 著者 | 遠藤 芳克| 酒井 亮| 大内 正明| 鬼松 秀樹| 日置 勝義| 香川 俊輔| 宇野 太| 渡邉 雄一| 浦田 泰生| 田中 紀章| 藤原 俊義| |
|---|---|
| 発行日 | 2008-12-01 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 120巻 |
| 号 | 3号 |
| 資料タイプ | 学術雑誌論文 |
| JaLCDOI | 10.18926/ESR/13952 |
|---|---|
| フルテキストURL | ESR_1_1.pdf |
| 著者 | 野坂 俊夫| 柴田 次夫| |
| 抄録 | Ultramafic rocks exposed around Mt. Ohsa(= Ohsa-yama), Okayama prefecture, designated as "Ohsa-yama ultramafic body" all together, are one of the Alpine-type peridotites in the Sangun metamorphic belt. They are intensely serpentinized and locally suffered contact metamorphism by younger granitic intrusions. In a por-tion of the ohsa-yama body where it has been affected by the contact metamorphism, the constituent minerals, texture and structure of primary ultramafic rocks have been locally preserved. Petrographic studies revead that the primary ultramafic rocks of the ohsa-yama body consist domimantly of dunite and harzburgite possessing no obvious layering, and their constituent minerals are similar in composition to those of the Tari-Misaka and Ashidachi ultramafic bodies. These features indicate that unlike the Ochiai-Hokubo body, the Ohsa-yama ultra-mafic body belongs to the "massive group" of the Arai's (1980) classification. |
| キーワード | petrography dunite harzburgite massive ultramafic body |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1994-09-20 |
| 巻 | 1巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 8 |
| 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 | 120002310594 |
| 著者 | 沼田 健之| |
|---|---|
| 発行日 | 1993-02-27 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 105巻 |
| 号 | 1-2号 |
| 資料タイプ | 学術雑誌論文 |
| JaLCDOI | 10.18926/ESR/13949 |
|---|---|
| タイトル（別表記） | Rb-Sr age of K-rich LL-chondrite Yamato-74442 |
| フルテキストURL | ESR_2_91.pdf |
| 著者 | 西谷 七代| 岡野 修| 加々美 寛雄| 中村 昇| |
| 抄録 | Yamato-74442, a brecciated LL-group chondrite, consists of fragments with igeous texture, chondrules, mineral fragments, and host. The fragments involve K-rich fragments as well as normal ones. Typically, both fragments consist mainly of euhedral porphyritic olivines and a few orthopyroxenes in a glassy grundmass. EPMA analyses for these fragments indicate that olivines and orthoptroxenes have a range of Fe/(Fe+Mg) ratio of 27.19～31.33 and 20.10～26.91 mol%, respectively. There is no significant difference in these rations between K-rich (Na2O/K2O<1) and normal framents. The K2O contents of groundmass for K-rich fragments range from 0.51 to 4.89 wt% and that of the normal fragments is 0.38～090 wt%. K2O contents of groundmass vary from fragment to fragment but are rather homegeneous in a single fragment. Rb-Sr isotopic determination on eighteen K-rich fragments (1.5 to 9.5mg in weight) gave an internal isochron age of 4.514±0.022 (2σ) Ga (λ87Rb=1.42×10-11y-1) and initial 87Sr/86Sr ratio of 0.7016±0.0024. This age is somewhat old compared with a whole rock isochron age of LL chondrites (4.493±0.18 Ga; Minster and Allegre, 1981). From a comoarison of the present result with others so far reported, it is inferred that the alkali differentiation as observed in Yamato-74442 probably occurred prior to or during a process of accumulation from LL chondrite parent material in the early solar nebula. |
| キーワード | LL-chondrite Rb-Sr age Sr isotope K-rich fragment |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1995-09-20 |
| 巻 | 2巻 |
| 号 | 1号 |
| 開始ページ | 91 |
| 終了ページ | 102 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 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 | 120002310270 |
| JaLCDOI | 10.18926/ESR/13948 |
|---|---|
| フルテキストURL | ESR_2_81.pdf |
| 著者 | Osae, Shiloh| 加瀬 克雄| 山本 雅弘| |
| 抄録 | The Ashanti gold deposit at Obuasi occurs in the Early Proterozoic Birimian formation. The orebodies consist of gold-sulphides disseminated in metasediments and metavolcanics, and gold-bearing quartz veins. Gold occurs mainly as native gold normally with arsenopyrite, pyrrhotite and pyrite in the metasediments and metavolcanics. In the quartz veins, however, it is associated with tetrahedrite and sphalerite. Microprobe analysis of gold grains gave an Ag content of about 8 wt.%. Textural relationships among the various mineral associations suggest that pyrrhotite, pyrite, arse-nopyrite and possibly gold may have been formed esrlier in the paragenetic sequence. The precipitation of some amounts of gold may have occurred during the later stages of the mineralisation sequence. Average arsenopyrite composition determined from electron microprobe study is: Fe: 33.6 ± 0.5 at.%, As: 29.3 ± 1.2 at.%, S: 37.1 ± 1.1 at.%, This suggests an average temperature of formation of less than 300℃ for the sulphides and possibly the gold assuming equilibrium was attained between pyrite, pyrrhotite and arsenpopyrite. The δ34S values for sulphide mineral separates are in the range between -4.1 and -10.8%. The values were, however, constrained between -4.1 and -7.0%. The narrow range and the depleted nature of the δ34S values may suggest a sedimentary sourcc of sulphur which may have undergone high temperature homegenisation before deposition. Sulphides from quartz vein samples had the most depleted δ34S values. This may indicate a different mineralisation history of the sulohides in the quartz veins from those dissemi-nated in metasediments and metavolcanics. |
| キーワード | Birimian Ashanti gold arsenopyrite |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1995-09-20 |
| 巻 | 2巻 |
| 号 | 1号 |
| 開始ページ | 81 |
| 終了ページ | 90 |
| 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 | 120002310561 |
| 著者 | 沼田 健之| |
|---|---|
| 発行日 | 1993-02-27 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 105巻 |
| 号 | 1-2号 |
| 資料タイプ | 学術雑誌論文 |
| 著者 | 村上 政江| |
|---|---|
| 発行日 | 1993-10 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 105巻 |
| 号 | 9-10号 |
| 資料タイプ | 学術雑誌論文 |
| 著者 | 石津 日出雄| 宮石 智| 山本 雄二| 高田 真吾| |
|---|---|
| 発行日 | 1993-10 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 105巻 |
| 号 | 9-10号 |
| 資料タイプ | 学術雑誌論文 |
| JaLCDOI | 10.18926/ESR/13938 |
|---|---|
| フルテキストURL | ESR_2_1.pdf |
| 著者 | 野坂 俊夫| 柴田 次夫| |
| 抄録 | The Ohsa-yama ultramafic body, which consists of several types of serpentinized peridotites, underwent contact metamorphism caused by a Cretaceous granite intrusion ; this metamorphism resulted in the formation of contact aureole, 1.5-2.0 km wide, around the granite intrusion, and produced progressive mineral changes in metaserpentinites toward the contact between the Ohsa-yama body and the granite intrusion. On the basis of analysis of mineral paragenetic relations, the Ohsa-yama ultramafic body can be divided into three zones with progressive changes in mineral assemblages as follows : Zone Ⅰ : serpentine ± chlorite ± brucite Zone Ⅱ : olivine + talc ± tremolite ± chlorite Zone Ⅲ : olivine + orthopyroxene ± tremolite ± spinel Zone Ⅰ corresponds to the parts unaffected by the thermal event, and Zones Ⅱ and Ⅲ correspond to the thermally metamorphosed parts of the Ohsa-yama body. The results obtained in this study are generally consistent with those of the previous studies on metamorphic peridotites from the Sangun and Muzuru zones. |
| キーワード | peridotite serpentinite thermal metamorphism contact metamorphism |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1995-09-20 |
| 巻 | 2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 | 120002310611 |
| JaLCDOI | 10.18926/ESR/13936 |
|---|---|
| フルテキストURL | ESR_3_57.pdf |
| 著者 | Okamoto Yasuhiko| 河原 昭| |
| 抄録 | The syntheses of kaliophilite have been carried out from the starting materials of near kalsilite compotions (KAISiO4), of which the AI2O3/SiO2 ratio is greater than 1/2. The X-ray powder deffraction pattern fit well to those of previous investigators. The crystal structure of synthetic kaliophilite was proposed by using the model consisting of four different types of kalsilite structure. The positions and intensities of the X-ray powder pattern were able to be explained on the basis of these four domains, belonging to thr twinning by merohedory. As a result of the conditions of the syntheses, it may be supposed that the violation of the AI-O-AI avoidanice rule can possibly exist along the domain boundaries. |
| キーワード | kaliophilite kalsilite synthese domain boundary |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1996-09-20 |
| 巻 | 3巻 |
| 号 | 1号 |
| 開始ページ | 57 |
| 終了ページ | 64 |
| 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 | 120002310557 |
| 著者 | 山手 智夫| |
|---|---|
| 発行日 | 1993-02-27 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 105巻 |
| 号 | 1-2号 |
| 資料タイプ | 学術雑誌論文 |
| JaLCDOI | 10.18926/ESR/13933 |
|---|---|
| タイトル（別表記） | Sulfur isotope ratios of some Roseki deposits in the Inner Zone of Southwest Japan |
| フルテキストURL | ESR_3_43.pdf |
| 著者 | 山本 雅弘| 松田 敏彦| 中川 頼記| |
| 抄録 | Sulfur isotope ratios of pyrite and alunite from 5 Roseki deposits in the Inner Zone of Southwest Japan were determined. The δ34S values of all pyrite samples were in the range from -13.2 to +2.3%, the variation range for each deposit being within 8%. In each deposit δ34S values of alunite were always higher than those of pyrite, which may be interpreted as that alunite was precipirated under more oxidizing conditions than pyrite. Sulfur isotope rations of the Roseki pyrite showed a distribution similar to that of ore sulfur from skarn and vein deposits in the same Zone. This suggests that the origin of sulfur of the Roseki deposits is also host igneous rocks. |
| キーワード | sulfur isotope ratio Roseki deposit pyrite alunite |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 1996-09-20 |
| 巻 | 3巻 |
| 号 | 1号 |
| 開始ページ | 43 |
| 終了ページ | 46 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 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 | 120002310309 |
| 著者 | 村上 宅郎| 田口 勇仁| 大塚 愛二| |
|---|---|
| 発行日 | 1993-02-27 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 105巻 |
| 号 | 1-2号 |
| 資料タイプ | 学術雑誌論文 |
| 著者 | 黒田 昌宏| 浅海 淳一| 西川 光治| 田中 聖了| 高 献書| 山本 道法| 巻幡 栄一| 平木 祥夫| 川崎 祥二| |
|---|---|
| 発行日 | 1993-02 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 105巻 |
| 号 | 1-2号 |
| 資料タイプ | 学術雑誌論文 |
| 著者 | 彌益 清文| |
|---|---|
| 発行日 | 1993-10 |
| 出版物タイトル | 岡山医学会雑誌 |
| 巻 | 105巻 |
| 号 | 9-10号 |
| 資料タイプ | 学術雑誌論文 |
| 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 |