result 18200 件
| JaLCDOI | 10.18926/ESR/13927 |
|---|---|
| FullText URL | ESR_3_1.pdf |
| Author | Daniel K. Asiedu| Suzuki, Shigeyuki| Shibata, Tsugio| |
| Abstract | Petrographic and geochemical study of sandstones from the Kenseki Formation have shown that the sandstones are compositionally immature. The immaturity is reflected geochemically by their low SiO2 contents (52-66 wt%) and petrographically by low modal percents of quartz and K-feldspar, and high modal percents of plagioclase and volcanic lithic fragmants. The Kensaki sandstones are, however, poor in Na2O (up to 2.1 wt%). Both petrography and geochemistry suggest a heterogeneous source lithologies of acidic and basic volcanics, sedimentary, and ultramafic rocks. Petrographic evidence is supplied by quartz and plagioclase of volcanic origin, acidic volcanic fragments, basic volcanic fragments, volcanic glass, serpentinite fragments and detrital spinel grains. Geochemical evidence is provided by high FeO* (total iron as FeO), MgO, TiO2, CaO and K2O contents. Petrographic and geochemical study of the Kenseki sandstones indicate calc-alkaline oceanic island are provenance. The sediments were locally derived, with Alpine-type ultramafic rocks exposed in the north and volcanic materials of the Akiyoshi Belt supplying the bulk of the detritus. |
| Keywords | Kenseki Formation modal analyses provenance |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1996-09-20 |
| Volume | volume3 |
| Issue | issue1 |
| Start Page | 1 |
| End Page | 16 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310277 |
| 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 |
| JaLCDOI | 10.18926/ESR/13922 |
|---|---|
| FullText URL | ESR_4_76.pdf |
| Author | Kawahara, Akira| |
| Abstract | 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. |
| Keywords | geneses of symmetry symmetry periododicity equilibrium |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1997-09-20 |
| Volume | volume4 |
| Issue | issue1 |
| Start Page | 79 |
| End Page | 96 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310432 |
| JaLCDOI | 10.18926/ESR/13921 |
|---|---|
| FullText URL | ESR_4_73.pdf |
| Author | Kohara, Shizuo| Kawahara, Akira| |
| Abstract | 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. |
| Keywords | silicate zinc silicate alumino-silicate framework ionic radii framework configu-ration |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1997-09-20 |
| Volume | volume4 |
| Issue | issue1 |
| Start Page | 73 |
| End Page | 78 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310344 |
| 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 |
| JaLCDOI | 10.18926/ESR/13919 |
|---|---|
| FullText URL | ESR_4_41.pdf |
| Author | Okamoto Yasuhiko| |
| Abstract | 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. |
| Keywords | kalsilite kaliophilite faldspathoid systheses crystal structre |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1997-09-20 |
| Volume | volume4 |
| Issue | issue1 |
| Start Page | 41 |
| End Page | 72 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310427 |
| 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 |
| JaLCDOI | 10.18926/ESR/13917 |
|---|---|
| Title Alternative | Ferroglaucophane schist from the Ohsa-yama srea, Okayama Prefecture, Japan |
| FullText URL | ESR_4_33.pdf |
| Author | Nozaka, Toshio| |
| Abstract | A ferroglaucophane schist occurs in fault contact with serpentinites at the Ohsa-yama area, Southwest Japan. It consists of albite, ferroglaucophane and actinolite with small amounts of stilpnomelane, sphene, apatite and K-feldspar. Petrological studies reveal that the schist was originally igneous rock of felsic or intermediate composition and has suffered two stages of metamorphism : ferroglaucophane has been formed at the first stage and actinolite at the second stage. In a basic schist from the same outcrop that the ferroglaucophane schist occurs, tremolitic amphibole instead of alkali amphibole has been formed along with chlorite, phengite and albite. Such a difference in mineral association between the schists is ascribed to a difference in whole rock composition, particu-larly in Fe/Mg ratio. Some of the schists from th Ohsa-yama area characteristically contain glaucophane or ferroglaucophane and have low Fe2O3/FeO ratios, forming a striking contrast to the crossite schists that commonly occur in the so-called "Sangun metamorphic terrane". These facts suggest that the alkali amphiboles of the Ohsa-yama schists were formed under higher P/T and more reducing conditions than those of the regional metamrphic rocks. On the other hand, development of the second-stage actinolite in the ferroglaucophane schist is consistent with the meta-morphic parageneses of greenschists from adjacent areas. Consequently the ferroglaucophane schist is considered one of the tectonic blocks that were captured by mobile serpentinites and have suffered the regional metamor-phism after the emplacement of the serpentinites into the present geologic position. |
| Keywords | ferroglaucophane petrology tectonic block serpentinite high P/T metamorphism, Ohsa-yama Sangun metamorphic terrane Southwest Japan |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1997-09-20 |
| Volume | volume4 |
| Issue | issue1 |
| Start Page | 33 |
| End Page | 40 |
| 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 | 120002310538 |
| JaLCDOI | 10.18926/ESR/13915 |
|---|---|
| Title Alternative | Three-dimensional structure of P wave velocity in the crust and upper mantle beneath southwest Japan |
| FullText URL | ESR_4_1.pdf |
| Author | Tanaka, Takashi| Oda, Hitoshi| |
| Abstract | Trevel-time data of the P wave were inverted to study three-dimensional structure of the P wave velocity in the upper mantle and crust beneath the Shikoku and Chugoku districts, southwest Japan. Low-velocity and high-velocity regions were found in the upper crust of the eastrn and western regions in the Shikoku district, respectively. The activity of crustal earthquakes is high in the eastern region. Moreover a significant high-velocity region exists in the uppermost mantle, where the activity of small earthquakes is very high. A low-velocity region with velocity of 7.0km/s was found just above the descending Philippine Sea plate with high velocity of 8.0 km/s. This region is continued to oceanic crust in the vicinity of the Nankai trough and its velocity is nearly equal to the P wave velocity (6.7 km/s) of oceanic crust. Thus the low velocity is interpreted as the oceanic crust. A high-velocity region is found below the depth of 50km in the Shikoku district. This region suggests the Philippine sea plate lying horizontally from the Shikoku districts to the ocast of the Seto Inland Sea of the Chugoku district. A low-velocity zone suggesting the volcanic front is found around the depth of 50km at the coast of the Japan Sea of the Chugoku distrit. |
| Keywords | Three-dimenrsional structure P wave Crust Upper mantle Philippine Sea plate |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1997-09-20 |
| Volume | volume4 |
| Issue | issue1 |
| Start Page | 1 |
| End Page | 20 |
| 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 | 120002310209 |
| Author | Tanaka, Seiryou| |
|---|---|
| Published Date | 1993-08 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume105 |
| Issue | issue7-8 |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/ESR/13912 |
|---|---|
| FullText URL | ESR_5_17.pdf |
| Author | Yamamoto, Masahiro| Kase, Katsuo| Harada, Kaori| |
| Abstract | 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. |
| Keywords | Sulfur isotope ratio Besshi-type deposit Tsuchikura mine Pyrite Chalcopyrite |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1998-09-20 |
| Volume | volume5 |
| Issue | issue1 |
| Start Page | 17 |
| End Page | 22 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310378 |
| Author | Sato, Kyo| |
|---|---|
| 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/13908 |
|---|---|
| FullText URL | ESR_6_39.pdf |
| Author | Yamamoto Masahiro| Ichimoto Hideo| Komatsu Shinji| Yamashita Ruka| |
| Abstract | 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. |
| Keywords | Hydrogen isotope ratio Oxygen isotope ratio Sulfur isotope ratio Thermal water Spa Okayama |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1999-09-20 |
| Volume | volume6 |
| Issue | issue1 |
| Start Page | 39 |
| End Page | 44 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310408 |
| JaLCDOI | 10.18926/ESR/13907 |
|---|---|
| Title Alternative | Chemical and Rb-Sr isotopic features of the shock-melted chondrite Yamato-793533 |
| FullText URL | ESR_6_29.pdf |
| Author | Okano, Osamu| Katayama, Hiroko| Nakamura, Noboru| |
| Abstract | The Sr isotopic compositions and Rb and Sr abundances, as well as major element abundances in olivine, pyroxenes and glass, were determined for a chip and 21 fractions separated from a shock-melted chondrite Yamato-793533, a dark-colored, porous stone with glassy texture. Two lithologies were recognized for the 1.5g specimen studied (Yamato-793533, 67) ; L (Main portion) and L to LL (Dark portion) chondritic in terms of chemical compositions of olivine and pyroxenes. The chemical compositions of glass are relatively homogeneous (SiO2=67-77%) compared to those of other ordinary chondrites, suggesting a moderate cooling rate after shock-melting. The data points for fractions do not foem any isochron in a 87Rb/86Sr vs. 87Sr/86Sr diagram. However, it is noted that six out of nine points for the dark portion plot around a 1.2 Ga line, while most of points for the main portion plot around a 4.55 Ga chondrite isochron. The observed difference could be responsible for difference in melting degrees between the two portions. Similar Rb-Sr features have been found among shock-melted Yamato-79 LL-chondrites which are considered to be paired stones experienced the same shock-melting event at 1.2 Ga. Consequently, the Rb-Sr systematics as well as petrologic features strongly suggest that Yamato-793533 is a member of a series of the shock-melted Yamato-79 LL-chondrites. |
| Keywords | LL-chondrite Shock-melting Sr isotope |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1999-09-20 |
| Volume | volume6 |
| Issue | issue1 |
| Start Page | 29 |
| End Page | 38 |
| 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 | 120002310391 |
| JaLCDOI | 10.18926/ESR/13905 |
|---|---|
| Title Alternative | Measurements of CO2 in air and sea over the Western Pacific-MR98-04 Cruise- |
| FullText URL | ESR_6_13.pdf |
| Author | Kono, Takehiko| Yamashita, Eiji| Nogami, Terumasa| Tsukamoto, Osamu| |
| Abstract | It is well known that the ocean plays a very important role in the overall geochemical cycle of CO2. Over the ocean surface, CO2 is equilibrated between partial pressure of CO2 in the seawater (pCO2) and that in the atmosphere(PCO2). The objectives of the present observation are to evaluate the following : (1) Horizontal distribution of pCO2 and PCO2, (2) Sea surface CO2 flux and (3) Vertical distribution of pCO2. |
| Keywords | Western Pacific pCO2 PCO2 Horizontal distribution CO2 flux Vertical distribution |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1999-09-20 |
| Volume | volume6 |
| 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 | 120002310525 |
| JaLCDOI | 10.18926/ESR/13904 |
|---|---|
| FullText URL | ESR_6_1.pdf |
| Author | Inoue, Yoshinori| Kase, Katsuo| |
| Abstract | 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. |
| Keywords | Phlogopite Hornblende Ultramafic complex Dunite Harzburgite Chromitite Contact metamor-phism Yanomine |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 1999-09-20 |
| Volume | volume6 |
| Issue | issue1 |
| Start Page | 1 |
| End Page | 12 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310269 |
| Author | Sato, Kyo| |
|---|---|
| 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/13902 |
|---|---|
| FullText URL | ESR_7_47.pdf |
| Author | Yamagiwa Nobuo| Suzuki, Shigeyuki| Okimura Yuji| |
| Abstract | 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. |
| Keywords | Early Carboniferous rugosa Lithostrotion (Siphonodendron) Hina Limestone Okayama |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2000-09-20 |
| Volume | volume7 |
| Issue | issue1 |
| Start Page | 47 |
| End Page | 50 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310319 |
| JaLCDOI | 10.18926/ESR/13899 |
|---|---|
| FullText URL | ESR_7_27.pdf |
| Author | Henmi, Chiyoko| Kusachi, Isao| Kagetama Tatsuya| |
| Abstract | 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. |
| Keywords | aegirine aegirine-augite diopside pyroxene hybrid rock skarn |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2000-09-20 |
| Volume | volume7 |
| Issue | issue1 |
| Start Page | 27 |
| End Page | 34 |
| ISSN | 1340-7414 |
| language | English |
| Copyright Holders | 岡山大学地球科学研究報告編集委員会 |
| File Version | publisher |
| NAID | 120002310313 |
| Author | Jisho, Takayoshi| |
|---|---|
| Published Date | 1994-12 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume106 |
| Issue | issue11-12 |
| Content Type | Journal Article |
