result 1716 件
| Author | Shinozaki, Mai| Yanagitani, Masahiko| Kaneda, Shouichirou| Kudou, Daizou| Endou, Yuuichi| Tamura, Takashi| Kuramitsu, Seiki| Inagaki, Kenji| |
|---|---|
| Published Date | 2010-02-01 |
| Publication Title | 岡山大学農学部学術報告 |
| Volume | volume99 |
| Issue | issue1 |
| Content Type | Departmental Bulletin Paper |
| JaLCDOI | 10.18926/ESR/19850 |
|---|---|
| Title Alternative | 岡山県に分布する白亜紀前期羽山層砕屑物質の供給源：砕屑粒の鉱物化学組成とモード組成から導かれる制約 |
| FullText URL | 016_029_042.pdf |
| Author | Asiedu, Daniel K.| Suzuki, Shigeyuki| Shibata, Tsugio| |
| Abstract | Petrographic and phase chemistry studies of detrital grains were carried out on sandstones from the Lower Cretaceous Hayama Formation, Inner Zone of Southwest Japan, to determine their provenance and the tectonic setting during the early Cretaceous. The results of the modal mineralogy suggest that the Hayama Formation has magmatic arc provenance and that deposition of the sediments took place in the back-arc areas with detritus mostly derived from the magmatic arc and rifted continental margins. The chemical compositions of chromian spinel, chlorite and sphene indicate that significant proportions of the detrital grains were derived from mafic and/or ultramafic sources. The source areas are the mafic and ophiolitic rocks in the Sangun-Renge and Akiyoshi terranes and the felsic volcanic rocks probably from either the Akiyoshi terrane or a source not presently exposed in southwest Japan. However, minor amounts of the detritus were derived from the basement rocks; i.e., carbonates and siliciclastic rocks of the Akiyoshi terrane and the metamorphosed mafic rocks of the Chizu terrane. |
| Keywords | modal analysis sandstone mineral chemistry provenance Hayama Formation |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2009-12-25 |
| Volume | volume16 |
| Issue | issue1 |
| Start Page | 29 |
| End Page | 42 |
| 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 | 120002309000 |
| JaLCDOI | 10.18926/ESR/19849 |
|---|---|
| Title Alternative | ガーナ，アシャンティ火山帯南部に分布する古原生代変火山岩類のSr-Nd 同位体組成 |
| FullText URL | 016_009_028.pdf |
| Author | Dampare, Samuel| Shibata, Tsugio| Asiedu, Daniel| Okano, Osamu| Manu, Johnson| Sakyi, Patrick| |
| Abstract | Neodymium (Nd) and strontium (Sr) isotopic data are presented for Paleoproterozoic metavolcanic rocks in the southern part of the Ashanti volcanic belt of Ghana. The metavolcanic rocks are predominantly basalts/basaltic andesites and andesites with minor dacites. Two types of basalts/basaltic andesites (B/A), Type I and Type II, have been identified. The Type I B/A are stratigraphically overlain by the Type II B/A, followed by the andesites and the dacites. The analyzed volcanic rocks commonly have low initial (87)Sr/(86)Sr ratios consistent with previous studies on Paleoproterozoic rocks from the West African craton. The LREE-depleted, tholeiitic Type I B/A exhibit back-arc basin geochemical signatures and show high positive epsilon Nd (i.e., ε(Nd) (2.1 Ga) = +3.89 to +7.21), which suggest a long term depleted source and also indicate that they were produced in an entirely oceanic environment devoid of influence of continental crust. The isotope signatures are thus consistent with the previously published trace element data of the Type I basalts/basaltic andesites in suggesting that their parent magma was generated from a depleted mantle. The Type I B/A have Nd model ages (T(DM2)) of 1.83–2.09 Ga similar to their formation ages, suggesting that they were juvenile at their time of formation. The andesites and the Type II B/A andesites show LREE-enriched patterns and exhibit characteristics of subduction zone-related magmas, and show initial ε(Nd) (2.1Ga) values of –1.15 to + 1.35 and Nd model ages (T(DM2)) of 2.32–2.58 Ga. The LREE-enriched dacitic porphyry also exhibits characteristics of subduction zone-related magmas, and have initial ε(Nd) (2.1Ga) value of –2.24 and Nd model ages (T(DM2)) of 2.64 Ga. The Nd isotopic data confirms the juvenile character of the Birimian crust, but also suggests some contributions of a pre-Birimian crustal material (or Archean?) in the genesis of some of the metavolcanic rocks. Our isotopic result is consistent with the island arc complex model which views Paleoproteozoic terranes of West Africa in the context of subduction–accretion processes. |
| Keywords | Sr–Nd isotopes petrogenesis tectonic setting Birimian metavolcanics Ashanti volcanic belt |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2009-12-25 |
| Volume | volume16 |
| Issue | issue1 |
| Start Page | 9 |
| End Page | 28 |
| 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 | 120002308985 |
| JaLCDOI | 10.18926/ESR/19848 |
|---|---|
| Title Alternative | The first Japanese word "chishitsu-gaku" for the "geology" was proposed by Genpo Mitsukuri (1799-1863) |
| FullText URL | 016_001_007.pdf |
| Author | Okada, Hakuyu| Suzuki, Shigeyuki| |
| Abstract | The first Japanese word "chishitsu-gaku" for the "geology" was proposed by Genpo Mitsukuri, a scientific contributor in the Tokugawa regime in the 19th century, who was born in 1799 in Tsuyama in Western Honshu, Japan and had worked for scientific activities of the Tokugawa government from 1839 to 1863. His major works for the first making of the "chishitsu-gaku" for the "geology" have been presented in this paper, also showing his contribution to Japanese sciences. |
| Keywords | Genpo Mitsukuri "chishitsu-gaku" 19th century |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2009-12-25 |
| Volume | volume16 |
| Issue | issue1 |
| Start Page | 1 |
| End Page | 7 |
| 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 | 120002309076 |
| Author | Kimoto, Tetsuo| Otani, Kyoichiro| Yabe, Tadayoshi| Takeda, Tositeru| Shiomi, Humitoshi| |
|---|---|
| Published Date | 1956-10-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue10 |
| Content Type | Journal Article |
| Author | Oguchi, Motomitsu| |
|---|---|
| Published Date | 1956-10-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue10 |
| Content Type | Journal Article |
| Author | Oguchi, Motomitsu| |
|---|---|
| Published Date | 1956-10-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue10 |
| Content Type | Journal Article |
| Author | Oguchi, Motomitsu| |
|---|---|
| Published Date | 1956-10-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue10 |
| Content Type | Journal Article |
| Author | Oguchi, Motomitsu| |
|---|---|
| Published Date | 1956-10-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue10 |
| Content Type | Journal Article |
| Author | Shiigi, Teiji| |
|---|---|
| Published Date | 1956-09-30 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue9 |
| Content Type | Journal Article |
| Author | Shiigi, Teiji| |
|---|---|
| Published Date | 1956-09-30 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue9 |
| Content Type | Journal Article |
| Author | Shiigi, Teiji| |
|---|---|
| Published Date | 1956-09-30 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue9 |
| Content Type | Journal Article |
| Author | Yamasaki, Hidemasa| Jinzenji, Kei| Kondo, Kazuji| |
|---|---|
| Published Date | 1959-04-25 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume71 |
| Issue | issue5-2 |
| Content Type | Journal Article |
| Author | Ohkura, Yusuke| |
|---|---|
| Published Date | 1956-08-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue8 |
| Content Type | Journal Article |
| Author | Ohkura, Yusuke| |
|---|---|
| Published Date | 1956-08-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue8 |
| Content Type | Journal Article |
| Author | Akamatsu, Osamu| |
|---|---|
| Published Date | 1956-08-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue8 |
| Content Type | Journal Article |
| Author | Michinaka, Tomokatsu| |
|---|---|
| Published Date | 1956-07-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue7 |
| Content Type | Journal Article |
| Author | Michinaka, Tomokatsu| |
|---|---|
| Published Date | 1956-07-31 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume68 |
| Issue | issue7 |
| Content Type | Journal Article |
| Author | Moriya, Takeo| |
|---|---|
| Published Date | 1959-04-25 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume71 |
| Issue | issue5-2 |
| Content Type | Journal Article |
| Author | Moriya, Takeo| |
|---|---|
| Published Date | 1959-04-25 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume71 |
| Issue | issue5-2 |
| Content Type | Journal Article |
