Author Department of Earth Sciences, Faculty of Science, Okayama University|
Published Date 2009-12-25
Publication Title Okayama University Earth Science Report
Volume volume16
Issue issue1
Content Type Others
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
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/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
Author Department of Earth Sciences, Faculty of Science, Okayama University|
Published Date 2009-12-25
Publication Title Okayama University Earth Science Report
Volume volume16
Issue issue1
Content Type Others
FullText URL esr_023_1_contents_eng.pdf
Author Department of Earth Sciences, Faculty of Science, Okayama University |
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
ISSN 1340-7414
language Japanese
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
FullText URL esr_023_1_titlepage.pdf
Author Department of Earth Sciences, Faculty of Science, Okayama University |
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
ISSN 1340-7414
language Japanese
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
JaLCDOI 10.18926/ESR/55321
Title Alternative Risk prediction of landslide and debris flow using slope gradation map obtained from airborne laser scanning
FullText URL esr_023_1_001_007.pdf
Author Suzuki, Shigeyuki| Miyashita, Masashi| Hirakawa, Takeshi| Fujiwara, Mieko| Nishiyama, Satoshi|
Abstract The slope gradation map which is obtained from airborne laser scanning is very important tool to detect hazardous sites of landslide, debris flow and others. The features of the images (what the images are represented) in the map were confirmed by field survey. The study area, Tamagashi is situated in the Kibi Plateau area, Okayama City, Japan. The map helps to distinguish between artificial microrelief and natural microtopography very well. Small scarps (even 0.5m high), rocky cliffs and large blocks (larger than 2m) are identified in the map. The detail images of the microrelief suggest threatening sites. The merit of the map leads us to find the site in the field easily. We will not miss the threatening sites by using the map.
Keywords Risk prediction slope gradation map airborne laser scanning landslide debris flow Okayama
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
Start Page 1
End Page 7
ISSN 1340-7414
language Japanese
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
JaLCDOI 10.18926/ESR/55322
FullText URL esr_023_1_009_015.pdf
Author Takesue, Norito| Suzuki, Shigeyuki|
Abstract Analyzing of sedimentary facies and structure together with regional field mapping were studied in the mélange unit, upper Cretaceous Shimanto Belt, Wakayama Pref., SW Japan. The field survey was concentrated in the coast of Shiofuki-iwa, Miyama Complex, Hidakagawa Belt where soft deformations penetrate throughout the mélange unit. Brittle to ductile faults associated as later deformations are excluded. The mélange unit is subdivided into the Y-shear zone (YSZ) and P-foliation zone (PFZ). The YSZ is composed of thick lenticular sandstone (trends subparallel to the direction of the mélange), intense shear band (thin layer with concentrated prelithification shear deformation) and mudstone dominant mélange. The PFZ is composed of mudstone dominant mélange (associated with foliations which slightly oblique to the direction of the YSZ) and lenticular sandstone (slightly oblique to the direction of the YSZ). The intense shear band separates the YSZ and PFZ. Preserved radiolarian fossils free from deformation in the intense shear band is the evidence of the prelithification shear deformation in the mélange. A remarkable-fact is that the structures of mélange unit are formed under sinistral sense of shear. The mélange unit in the Shiofuki-iwa is ascribed to be formed by sinistral sense of shear during sediments were prelithified.
Keywords mélange Shimanto Belt Y-shear zone P-foliation zone intense shear band prelithification structures
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
Start Page 9
End Page 15
ISSN 1340-7414
language English
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
JaLCDOI 10.18926/ESR/55323
Title Alternative Synoptic climatological analyses on the rainfall features in southern Kyushu and the atmospheric fields around April
FullText URL esr_023_1_017_032.pdf
Author Kato, Kuranoshin| Morizuka, Nozomi| Matsumoto, (Kengo| Otani, Kazuo|
Abstract Around April, total precipitation in southern Kyushu already attains rather large value due to the increase in contribution of the “heavy rainfall days” (with daily precipitation more the 50 mm/day, referred to as HRD). The present study examined the rainfall features and atmospheric conditions on the HRDs at Kagoshima in southern Kyushu, based on the operational observation data from 1990 to 2009. The HRDs there in April appeared mainly associated with the extratropical cyclone passage, together with tentative appearance of the stationary front. The mean daily precipitation on the HRDs was 82 mm and contribution of the intense rainfall more than 10 mm/h attained up to 38 mm, which accounted for 46 % of the daily total precipitation. In April, the high specific humidity area in the time mean field was still located far to the south of the Japan Islands and the stratification around the Japan Islands was very stable for deep moist convection. However, the zone with rather strong seasonal mean baroclinicity extended to rather southern area near 20°N. This would provide a favorable condition for the long-distance moistur
Keywords heavy rainfall around April in southern Kyushu rainfall associated with extratropical cyclones around the Japan Islands seasonal cycle around Japan
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
Start Page 17
End Page 32
ISSN 1340-7414
language Japanese
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
JaLCDOI 10.18926/ESR/55324
Title Alternative A case study on the cyclone activity around Europe from winter to spring of 2000
FullText URL esr_023_1_033_042.pdf
Author Kuwana, Yusuke| Kato, Kuranoshin| Takigawa, Yumi| Kojima, Yumi| Otani, Kazuo|
Abstract Although the extratropical cyclone is one of the basic systems that characterize the weather and climate in mid-latitude regions with the large meridional temperature gradient, its activity and characteristics would be greatly influenced by the seasonal transition and regional differences of the mean atmospheric fields such as between Europe and East Asia. Furthermore, detailed knowledge of the daily cyclone activity would help to understand deeply the differences of regional climatology including seasonal cycles among various areas. In such interest, the present study performed a case study on the cyclone activity around Europe from winter to spring of 2000. In winter, intraseasonal variation of the Icelandic Low was dominant. In the stage when such intraseasonal-scale Icelandic Low approached to the northwestern Europe, the several lows passed eastward with a few days interval around the intraseasonal-scale low pressure area or its southern edge where the baroclinicity was relatively strong. It is also noted that their center pressure was rather low (below 980hPa). After April, when the seasonal mean Icelandic low had disappeared, different types of the intra-seasonal-scale cyclones and anticyclones were dominantly observed. In the lower SLP stage of the intraseasonal variation in Europe, the low to the southwest of England in the middle of April was of the equivalent barotropic structure and persisted for about ten days. On the other hand, high pressure area extending from England to the northern coast of Germany also persisted for about half month. The southern half of that high area was also of equivalent barotropic structure with warmer air there.
Keywords cyclone activity around Europe comparative climatology between Europe and East Asia seasonal cycle dynamic climatology
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
Start Page 33
End Page 42
ISSN 1340-7414
language Japanese
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
FullText URL esr_023_1_colophon.pdf
Author Department of Earth Sciences, Faculty of Science, Okayama University |
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
ISSN 1340-7414
language Japanese
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
FullText URL esr_023_1_contents.pdf
Author Department of Earth Sciences, Faculty of Science, Okayama University |
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
ISSN 1340-7414
language Japanese
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
Author Department of Earth Sciences, Faculty of Science, Okayama University|
Published Date 2011-12-26
Publication Title Okayama University Earth Science Report
Volume volume18
Issue issue1
Content Type Others
Author Department of Earth Sciences, Faculty of Science, Okayama University|
Published Date 2011-12-26
Publication Title Okayama University Earth Science Report
Volume volume18
Issue issue1
Content Type Others
JaLCDOI 10.18926/ESR/47746
Title Alternative KED estimated distribution of Earth Scientific Information
FullText URL esr_018_1_001_003.pdf
Author Yamakawa, Junji| Ebi, Takahiro| Matsumoto, Hirofumi|
Abstract KED, the Kriging with External Drift, is one of the spatial statistical method for estimating some distribution from the discrete spatial sampled data set about the research field. The KED uses the kriging method (Matheron, 1973) with some auxiliary map to minimize the estimated error. The KED procedure was performed by the R-Language (Ihaka and Gentleman, 1996) using some geostatistical libraries. The auxiliary maps required by the KED were prepared by the authors with some GIS applications. The 3-dimensional geographic representations for the estimated distribution were performed by the Google Earth (Google, 2011). In this report, the KED was applied to some Earth scientific information to show the fundamental scheme of the method.
Keywords KED Universal kriging Regression kriging R-Language Google Earth
Publication Title Okayama University Earth Science Report
Published Date 2011-12-26
Volume volume18
Issue issue1
Start Page 1
End Page 3
ISSN 1340-7414
language Japanese
Copyright Holders © 2011 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
NAID 120003796474
JaLCDOI 10.18926/ESR/47747
Title Alternative Newly proposed landform division in the Kibi Plateau area: Application for a hazard map of landslides
FullText URL esr_018_1_005_010.pdf
Author Suzuki, Shigeyuki| Omizo, Yuna| Hirata, Minoru| Nishigaki, Makoto|
Abstract The Kibi Plateau is characterized by horizontal skylines and they are considered to be an uplifted peneplain. Landform of the plateaus in central part of Okayama Prefecture is divided into "Kibi plateau landform" and "Recent dissecting landform". The Kibi plateau landform is composed of low relief surface and relict mountain. The altitude of the low relief surface varies from 300 to 450m in Kayo area, and 200 to 350m in Kanayama area. The Recent dissecting landform is characterized by escarpment and cuts the Kibi plateau landform. Knick-point is formed at the boundary between two landforms and steep slope is distributed just below the knick-point. The steep slope of the recent dissecting landform is unstable and a potential of landslide is high.
Keywords Kibi Plateau landslide knick-point Okayama Prefecture
Publication Title Okayama University Earth Science Report
Published Date 2011-12-26
Volume volume18
Issue issue1
Start Page 5
End Page 10
ISSN 1340-7414
language Japanese
Copyright Holders © 2011 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
NAID 120003796475
JaLCDOI 10.18926/ESR/47748
Title Alternative Characteristics of typhoon tracks and large-scale atmospheric fields associated with the typhoon approach to the Japan Islands in early summer
FullText URL esr_018_1_011_018.pdf
Author Hamamoto, Natsumi| Kato, Kuranoshin| Nakayama, Yuuki| Tsukamoto, Osamu|
Abstract The number of typhoons approaching the Japan Islands is much smaller in May and June than in August to September. However, some typhoons abnormally approach to the Japan Islands in May or June as in 2004. The present study investigated the characteristics of the typhoon tracks and the large-scale fields in May and June associated with the approach of typhoons to the Japan Islands. Climatologically speaking, typhoons are generally formed in the lower latitude in May and early June, and tend to turn to ENE-ward before they reach ~ 20N in May by the upper- and middle-level westerly wind. In June, the upper-level easterly wind associated with the Tibetan high seems to prevent typhoons from approaching to the Japan Islands. However, when the cell-type subtropical high and the deep westerly trough in its western side are formed with the SW-ly from the lower to the middle latitude, a favorable situation for the northward invasion of the typhoon can be realized in May. On the other hand, the formation of the barotropic-like subtropical high to the southeast of the Japan Islands seems to enable a typhoon to approach to the Japan Islands by the S-ly wind around the subtropical high.
Keywords typhoon tracks in early summer large-scale atmospheric fields in early summer
Publication Title Okayama University Earth Science Report
Published Date 2011-12-26
Volume volume18
Issue issue1
Start Page 11
End Page 18
ISSN 1340-7414
language Japanese
Copyright Holders © 2011 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
NAID 120003796476
Author Department of Earth Sciences, Faculty of Science, Okayama University|
Published Date 2011-12-26
Publication Title Okayama University Earth Science Report
Volume volume18
Issue issue1
Content Type Others
Author Department of Earth Sciences, Faculty of Science, Okayama University|
Published Date 2009-12-25
Publication Title Okayama University Earth Science Report
Volume volume16
Issue issue1
Content Type Others