result 35246 件
| JaLCDOI | 10.18926/ESR/13949 |
|---|---|
| Title Alternative | Rb-Sr age of K-rich LL-chondrite Yamato-74442 |
| FullText URL | ESR_2_91.pdf |
| Author | Nishiya, Nanayo| Okano, Osamu| Kagami, Hiroo| Nakamura, Noboru| |
| Abstract | 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. |
| Keywords | LL-chondrite Rb-Sr age Sr isotope K-rich fragment |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1995-09-20 |
| Volume | volume2 |
| Issue | issue1 |
| Start Page | 91 |
| End Page | 102 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310270 |
| JaLCDOI | 10.18926/ESR/13947 |
|---|---|
| FullText URL | ESR_2_71.pdf |
| Author | Frank k, Nyame| Kase, Katsuo| Yamamoto, Masahiro| |
| Abstract | X-ray diffraction, ore microscopy, and electron microprobe studies have been done on ore samples obtained from the mine site at Nsuta, Ghana. Manganese ore minerals identified include nsutite, cryptomelane, pyrolusite, and lithiophorite. Except for pyrolusite, all these minerals are poorly crystalline. Chemical compositions of the minerals indicate little contamination by other elements. Quartz, muscovite, and clay minerals feature prominently as gangue in most samples. Textures are varied, and modes of occurrence are prinicipally by replacements, cavity or fracture fills, leaching and precipitaion. Mineral associations seem rather complex, as a result of which definitive paragenetic relations could not be established. Supergene formation of the manganese oxide ore is shown by the abundance of manganese minerals in solution channels such as fractures and cavities within silicate gangue. Much of the ore, howver, appears to have been enriched by leaching of gangue minerals and the later addution of manganese. |
| Keywords | Nsuta nsutite cryptomelane pyrolusite lithiophorite |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1995-09-20 |
| Volume | volume2 |
| Issue | issue1 |
| Start Page | 71 |
| End Page | 80 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310527 |
| Author | Numata, Takeyuki| |
|---|---|
| Published Date | 1993-02-27 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue1-2 |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/ESR/13945 |
|---|---|
| Title Alternative | solubility and polymerization of silica in salt solutions |
| FullText URL | ESR_2_63.pdf |
| Author | Sugita, Hajime| Yamamoto, Masahiro| |
| Abstract | The solubility of amorphous silica was determined in sodium chloride,potassium chloride, magnesium chloride and calium chloride solutions from 0.01 to 1moI/I and at temperatures of 21,36,50 and 65℃. The Setchenow equation was applied to the results, which enabled us to estimate the equilibrium concentration of "dissoloved silica" (molybdate-reactive silica) in the studied chloride solutions. Next, the effects of pH, supersaturation of silica and salt concentration on the polymerization rate of silica were investigated at 35℃. In the pH range from 6.4 to 7.9, the maximum polymerization rate increased with increasing pH. The maxima occurred when dissoloved silica decreased by 25% of the initial supersaturation concentrations irrespective of pH. The polymerization rate was found to be dependent on the supersaturation degree rather than on the supersaturation concentration of silica. The results in magnesium chloride solutions suggest that magnesium ions may act as nuclei in the formation of colloidal silica in geothermal waters. |
| Keywords | amorphous silica solubility polymerization |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1995-09-20 |
| Volume | volume2 |
| Issue | issue1 |
| Start Page | 63 |
| End Page | 70 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310447 |
| Author | Murakami, Masae| |
|---|---|
| Published Date | 1993-10 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue9-10 |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/ESR/13943 |
|---|---|
| Title Alternative | Water-soluble materials on volcanic ash from the 1990-94 eruption of the Unzenn volcano |
| FullText URL | ESR_2_55.pdf |
| Author | Akagi, Seishi| Yamamoto, Masahiro| |
| Abstract | Water-soluble materials on volcanic ash from the Unzen volcano collected from February, 1991 to July, 1994 were chemically analyzed. They were similar in chemical characteristics to those obtained from other volcanoes. Chemical compositions varied even for materials from the same pyroclastic flow. C1 contens increased with increasing residence time of volcanic ash in air, but SO4 contents were almost fixed. It therefore seems that the reaction of volcanic ash with HC1 proceeds even at low temperatures, whereas the reaction with SO2 takes place only at high temperatutes. |
| Keywords | volcanic ash volcanic gas Unzen volcano C1/SO4 ratio water-soluble material |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1995-09-20 |
| Volume | volume2 |
| Issue | issue1 |
| Start Page | 55 |
| End Page | 62 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310484 |
| Author | Munetomo, Kazuo| |
|---|---|
| Published Date | 1993-02-27 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue1-2 |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/ESR/13941 |
|---|---|
| Title Alternative | A suggestion on the origin of biotite gneisses of the Ryoke belt in the Seto Inland Sea (Seto-nai-kai) region : Some biotite gneisses were derived from a different geologic unit to the Kuga froup |
| FullText URL | ESR_2_23.pdf |
| Author | Nureki, Terukazu| |
| Abstract | The Kuga group is a Jurassic accretional complex that has been believed by many workers to be a unique geologic unit transformed into the Ryoke gneisses in the Seto Inland Sea region. I will now suggest the presence of a different geologic unti in addition to the Kuga group. Most of the biotite gneisses found at the Iwakuni-Yanai area are probably derived from rocks of the Kuga group, but the rest biotite gneisses that occur in the Murotu Peninsula, the Yashiro-jima, the E-no-shima, and the other several islands in the Seto Inland Sea region were derived from a un-known and a different geologic unit to the Kuga froup. Some pieces of evidence proving the distinct origin of the latter biotite gneisses are: (1) the biotite gneisses commonly occur as small to large fusiform bodies generally enclosed in the older Ryoke granite or as large masses contacting only with the older Ryoke granite; (2) tight folds with parallel axial surfaces are very common, and dupli-cated fold systems are found in many localities; (3) microtextures of some minerals, e.g. garnet and K-feldspar, often suggest a plural metamorphic history of the gneisses (Nuraki et al., 1982a; Miyashita % Komatsu,1993); and (4) the sillimanite zone (Ikeda,1991 : Okudaira et al.,1993) is only a metamorphic zone that can be found. The sillimanite zone is interpreted to be excluded from the progressive metamorphism in the Iwakauni-Yanai area (Wallits et al.,1992). Biotite gneisses of the sillimanite zone are found here and there and show no zonal arrangement of distribu-tion in the Ryoke belt. The estimated metamorphic temperature and pressures for the biotite gneisses of the silliman-ite zone are 530-710℃ and 2-4kb respectively, both of which are lower than of the peak metamorphism, estimated as 550-820℃ and 5-6kb, at the Iwakuni- Yanai area. |
| Keywords | Kuga group Ryoke belt biotie gneisses Sillimanite Zone Iwakuni-Yanai area |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1995-09-20 |
| Volume | volume2 |
| Issue | issue1 |
| Start Page | 23 |
| End Page | 54 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310501 |
| JaLCDOI | 10.18926/ESR/13940 |
|---|---|
| Title Alternative | Application of the remotely operated TV vehicle to make geological maps of the Seto Inland Sea |
| FullText URL | ESR_2_13.pdf |
| Author | Suzuki, Shigeyuki| Inada, Takashi| |
| Abstract | Submarine geological survey using the remotely operated TV vehicle (RV100), was carried out in 4 offshores of the Seto Inland Sea in Kagawa Prefecture. The study areas are west of Kosei Island of Sakaide City, south of Okado-bana of Nankai Town, west of Misaki of Takuma Town and north of Nou-Misaki of Sakaide City. TV vehicle transmite clear pictures of bottom of the sea to the monitor on board. The submarine geology of the study areas are composed of Cretaceous granitic basements and Quaternary sedimentary covers. By using these pictures Recent and Pleistocene deposits could be distinguished and lithology of sediments could also be identified. Lithology of sediments was however difficult to identify using the usual sonic prospecting method. Furthermore, pictures suggesting that ripples are just forming have been obtained. The TV vehicle is convenient in submarine survry, because it can travel much longeer and deeper than human diver. A new method of mapping submarine geology using TV vehicle was developed. |
| Keywords | Submarine geology the Seto Inland Sea remotely operated TV vehicle |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1995-09-20 |
| Volume | volume2 |
| Issue | issue1 |
| Start Page | 13 |
| End Page | 22 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310382 |
| Author | Ishizu, Hideo| Miyaishi, Satoru| Yamamoto, Yuji| Takata, Shingo| |
|---|---|
| Published Date | 1993-10 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue9-10 |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/ESR/13937 |
|---|---|
| Title Alternative | A microcomputer-controlled gradual cooling system for hydrothermal reactors |
| FullText URL | ESR_3_65.pdf |
| Author | Yamakawa, Junji| Kawahara, Akira| |
| Abstract | A used 8 bit microcomputer is applied for an instrument of controlling the heating temperatures of hydrothermal reactor furnaces. The temperatures were changed into appropriate values of voltage by thermocouples and additional devices. The interface board, programmable peripheral interface LSI and some IC's for addres decording are assembled into a complte unti. The device is useful for the inexpensive way of the construction of the accurate temperature control system. |
| Keywords | hydrothermal synthesis cooling system personal computer |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1996-09-20 |
| Volume | volume3 |
| Issue | issue1 |
| Start Page | 65 |
| End Page | 70 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310682 |
| Author | Yamate, Tomoo| |
|---|---|
| Published Date | 1993-02-27 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue1-2 |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/ESR/13933 |
|---|---|
| Title Alternative | Sulfur isotope ratios of some Roseki deposits in the Inner Zone of Southwest Japan |
| FullText URL | ESR_3_43.pdf |
| Author | Yamamoto, Masahiro| Matsuda, Toshihiko| Nakagawa, Raiki| |
| Abstract | 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. |
| Keywords | sulfur isotope ratio Roseki deposit pyrite alunite |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1996-09-20 |
| Volume | volume3 |
| Issue | issue1 |
| Start Page | 43 |
| End Page | 46 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310309 |
| Author | Murakami, Takuro| Taguchi, Takehito| Ohtsuka, Aiji| |
|---|---|
| Published Date | 1993-02-27 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue1-2 |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/ESR/13931 |
|---|---|
| Title Alternative | Inversion of normal mode frequencies for estimation of lateral heterogeneity of the earth's elasticity atructure: A numerical test |
| FullText URL | ESR_3_33.pdf |
| Author | Onishi, Seiji| Oda, Hitoshi| |
| Abstract | An investigation was made on effect of lateral heterogenity of the earth's elasticity structure on the normal mode frequencies. The lateral heterogeneity is expressed by an expansion of spherical harmonic functions, Pιm(cosθ)sinmΦ and Pιm(cosθ)cosmΦ, up to the second order harmonics (ι≤2). Free oscillation freguencies of the heterogeneous earth were computed by the xyz algorithm. Further we derived an analytic expression of partial derivatives of eigenfrequency with respect to the expansion coefficients, and performed a numerical test to verify whether or not it is possible to estimate the heterogeneity of the earth's structure by the inversion of noemal mode frequencies. When the earth is assumed to be elastically isotropic spheroid with short polar and long equatorial radii, frequency spectra affected by longitudinal heterogeneity terms, Pιm(cosθ)(sinmΦ, cosmΦ) (m≠ 0), for given values of ι and m coincide with each other, because these two terms describe the same heterogeneity when the earth is rotated by π/2m around rotation axis. In such a case, we cannot determine accurately the expansion coefficients of tha two heterogeneity terms by inversion of normal mode frequencies, whereas the coefficients of the latitudinal heterogeneity Pι0(cosθ) can be precisely determined. Therefore it is difficult to estimate of lateral heterogeneity of the earth's elasticity structure by the inversion of normal mode frequencies. |
| Keywords | Normal Mode Inversion Earth's Structure Lateral Heterogeneity |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1996-09-20 |
| Volume | volume3 |
| Issue | issue1 |
| Start Page | 33 |
| End Page | 42 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310694 |
| Author | Kuroda, Masahiro| Asaumi, Junichi| Nishikawa, Koji| Tanaka, Seiryo| Gao, Xian Shu| Yamamoto, Michinori| Makihata, Eiichi| Hiraki, Yoshio| Kawasaki, Shoji| |
|---|---|
| Published Date | 1993-02 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue1-2 |
| Content Type | Journal Article |
| Author | Yamasu, Kiyofumi| |
|---|---|
| Published Date | 1993-10 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue9-10 |
| Content Type | Journal Article |
| Author | 岡山リウマチ研究会| |
|---|---|
| Published Date | 1993-08 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue7-8 |
| Content Type | Others |
| Author | Shiiki, Shigeo| Nakagawa, Kazuhiro| Sasaki, Hiroshi| Yamashita, Yutaka| Yumura, Masahito| Kodani, Johji| Yunoki, Yasuhiro| Orita, Kunzo| |
|---|---|
| Published Date | 1993-02-27 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue1-2 |
| Content Type | Journal Article |
| Author | Kuroda, Muneaki| Iwagaki, Hiromi| Matsubara, Nagahide| Kimura, Toshikazu| Nonaka, Yasuyuki| Nezu, Masashi| Yoshinaga, Masao| Jikuhara, Atsushi| Hizuta, Akio| Orita, Kunzo| |
|---|---|
| Published Date | 1993-02-27 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue1-2 |
| Content Type | Journal Article |
