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JaLCDOI 10.18926/ESR/42457
Title Alternative 西南日本の熱変成超苦鉄質岩体中のかんらん石と輝石の組成変化に関する覚書
FullText URL esr_017_001_005.pdf
Author Nozaka, Toshio|
Abstract This short article presents some diagrams showing the compositional variations of primary and metamorphic olivine, orthopyroxene and clinopyroxene in peridotites and serpentinites from thermally metamorphosed ultramafic complexes in SW Japan. In contrast to olivine, which shows a gradual change of chemical composition corresponding with metamorphic grade, orthopyroxene and clinopyroxene show clear differences in composition between primary and metamorphic phases. Compared with primary pyroxenes, even though their compositions could be variable depending on original rock composition, metamorphic orthopyroxene and metamorphic clinopyroxene is clearly deficient in Cr(2)O(3) and CaO, and in Cr(2)O(3) and Al(2)O(3), respectively. These characteristics are useful for the discrimination between the pyroxenes of different origin.
Keywords chemical composition olivine orthopyroxene clinopyroxene metaperidotite
Publication Title Okayama University Earth Science Report
Published Date 2010-12-24
Volume volume17
Issue issue1
Start Page 1
End Page 5
ISSN 1340-7414
language English
Copyright Holders © 2010 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
NAID 120002753315
Author Department of Earth Sciences, Faculty of Science, Okayama University|
Published Date 2010-12-24
Publication Title Okayama University Earth Science Report
Volume volume17
Issue issue1
Content Type Others
Author Department of Earth Sciences, Faculty of Science, Okayama University|
Published Date 2010-12-24
Publication Title Okayama University Earth Science Report
Volume volume17
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
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/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 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
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/15034
Title Alternative 中国寧夏地域における日照時間から日積算日射量の推定
FullText URL 015_079_086.pdf
Author Yang, Qin| Tsukamoto, Osamu|
Abstract For the estimation of daily solar radiation from sunshine duration, observation data of Yinchuan station in Ningxia, China was used. Using a linear relationship between solar radiation and extraterrestrial radiation including relative sunshine duration and daylength, we obtained local coefficients s a =0.18, s b =0.62 from past five years data(1981-1985). Using the same method, coefficients for Guyuan region were confirmed too as a representative of south part of Ningxia province. Applying the local coefficients and calculation formula of solar radiation, we validated daily solar radiation of two years(1986-1987) of Yinchuan station and four years(1991-1994) of Guyuan station. The results showed high correlation coefficients of R2=0.94 in Yinchuan and R2=0.85 in Guyuan. Error analysis was applied using mean bias error(MBE), mean absolute bias error(MABE), root mean square error(RMSE),mean absolute percentage error(MAPE) on solar radiation of Yinchuan(1973-2006) and Guyuan(1986-2006) stations. Results showed that mean absolute bias error(MABE) was less than 13% and 17% in Yinchuan station and Guyuan station respectively. Then we have applied this method to the estimation of daily solar radiation at ‘Yongning’ station(near Yinchan) with the sunshine duration data at ‘Yongning’. The estimated values were compared with observed daily solar radiation at Yinchuan as past twelve years data(1989-2000). The results showed good linear relationship with high correlation coefficient of R2= 0.88.
Keywords Daily solar radiation Extraterrestrial radiation Relative sunshine duration Local coefficient
Publication Title Okayama University Earth Science Report
Published Date 2009-03-31
Volume volume15
Issue issue1
Start Page 79
End Page 86
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 120002307142
JaLCDOI 10.18926/ESR/15033
Title Alternative Climatological study on large-scale situation associated with the cool summer around the Northeastern Japan in 1990s (in comparison with that in 1970s)
FullText URL 015_067_077.pdf
Author Senoo, Yukari| Kato, Kuranoshin|
Abstract It is pointed out by the previous studies that the Baiu front tends to stagnate around the Japan Islands even in midsummer season in 1990s, although the global warming is going on. The present study examined the climatological features of the appearance of daily fronts on the surface weather maps and the large-scale factors associated with the activity of the polar frontal zone to the north of the Baiu frontal zone based on the observational data in the summer of 1971-2000. It was found that the midsummer when the Baiu front tends to stagnate around the Japan Islands appeared rather frequently in 1970s as in 1990s. However, the baroclinicity around the Eurasian polar frontal zone was stronger in 1970s than in 1990s. Thus while the fronts around the Japan Islands in midsummer were greatly due to the southward invasion of cold front associated with the disturbances on the polar frontal zone in 1970s, the Okhotsk High tends to stagnates to the northeast of the fronts around the Japan Islands in 1990s.
Keywords Abnormal weather in summer Climate system in East Asia Cool summer Climate variation
Publication Title Okayama University Earth Science Report
Published Date 2009-03-31
Volume volume15
Issue issue1
Start Page 67
End Page 77
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 120002307910
JaLCDOI 10.18926/ESR/15025
Title Alternative Morphology and Anatomy of Holocene Raised Coral Reef Terraces in Kodakara Island, Tokara Islands, northwestern Pacific, Japan
FullText URL 015_033_065.pdf
Author Hamanaka, Nozomu| Kan, Hironobu| Nakashima, Yosuke| Hori, Nobuyuki| Okamoto, Takehiro| Ohashi, Tomoya| Adachi, Hiroshi|
Abstract Well-developed Holocene raised coral reef terraces are formed in Kodakara Island (29°13'N 129°19'E), Tokara Islands, northwestern Pacific, Japan. Detailed morphology and sedimentary structure of the raised reef terraces are observed by field survey through the terraces surface and core drillings. The Holocene raised reef in Kodakara Island are divided into three terraces (TI to III). The surface geo-biological facies and paleo-morphology such as spur and groove system or reef mounds are well preserved on these terraces. The raised coral reefs in Kodakara Island consist of reef flats and reef slopes. No lagoon formed in these terraces. On the raised reef surface, we observed five distinct reefal facies (S-f1-5). The platy and encrusting Acropora facies is the major constituent of the terrace surfaces. We obtained seven drilling cores (B1 to 7) from Terraces I and II along a transect in the southern part of the island. The thickness of the Holocene reef is more than 14m which is approximately equivalent to the Holocene reefs in the middle and southern Ryukyu Islands. Sedimentary structure consists of seven facies (C-f1-7: five reefal and two non-reefal facies). The drilling cores indicating the shallowing sequence at the upward of the cores which characterized by platy-encrusting Acropora facies overlying massive Porites, favid and/or encrusting-foliaceous coral facies. It may indicate the environmental change such as wave-energy gradients and turbidity during the reef development.
Keywords Holocene coral reef terrace drilling sedimentary structure Tokara Islands northwestern Pacific
Publication Title Okayama University Earth Science Report
Published Date 2009-03-31
Volume volume15
Issue issue1
Start Page 33
End Page 65
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 120002308005
JaLCDOI 10.18926/ESR/15024
Title Alternative Microscopic observations of the recent soils: a step for understanding the paleosols
FullText URL 015_009_032.pdf
Author 福地 亮| Suzuki, Shigeyuki|
Abstract The microscopic observations of the recent soil horizons were conducted in Okayama, Japan (moderate climate). The several soil horizons, including two surface (epipedon) and three subsurface horizons, were recognized in the forest, poorly vegetated hill, and riverside around the Okayama University. The umbric epipedon can be segregated from the organic-rich subsurface horizons by the scattered organic materials in thin sections. The ochrich epipedon shows the sandy matrix without any cements and the illuviation of clay minerals. The subsurface horizons identified in the study area are as follows: albic, argillic, and cambic horizons. Each subsurface horizon shows the specific structures in thin sections. The albic horizon is characterized by the absence of the illuviation. The argillic horizon definitely shows the clayey matrix and the illuviation of clay minerals. The primary structures may be retained in the cambic horizon. The microscopic examination of the Miocene paleosols from the Ukan-cho, Okayama, was attempted. By comparing the recent soils, the cambic horizon and spodic horizon, which is characterized by the concentration of sesquioxides, are identified in the paleosols. This attempt suggests that the microscopic observations of the recent soils is a useful guide to understanding the paleosols
Keywords soil paleosol soil horizon soil structure microscopic observation
Publication Title Okayama University Earth Science Report
Published Date 2009-03-31
Volume volume15
Issue issue1
Start Page 9
End Page 32
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 120002307964
JaLCDOI 10.18926/ESR/15022
Title Alternative Permian and Triassic molluscan fossils from the Maizuru Zone,Okayama City, Southwest Japan
FullText URL 015_001_008.pdf
Author Nakazawa, Keiji| Roger Lyman Batten| Suzuki, Shigeyuki| Uwada, Hideto|
Abstract Permian and Triassic molluscan fossils are found from Mitsu-area, Okayama City, Southwest Japan. Permian bivalve and gastropod fossils are collected from mudstones of the Upper Formation of the Maizuru Group. 4 species of bivalves (Nuculopsis? sp. ind., Leptodesma sp. ind., Streblopteria cf. eichwaldi, Posidonia sp. ind.) and 5 species of gastropods (Worthenia cf. corrugata, Callitomaria n. sp. cf. stanislavi, Apachella n. sp. ind., ??Eunemopsis like trochid, ??Yunnania sp.) are identified. Lower Triassic bivalve fossils are collected from sandstones of the Oono Formation. Neoschizodus cf. laevigatus and Bakevellia (Maizuria) kambei are identified.
Keywords Permian Triassic bivalve and gastropod fossils the Maizuru Zone Mitsu area
Publication Title Okayama University Earth Science Report
Published Date 2009-03-31
Volume volume15
Issue issue1
Start Page 1
End Page 8
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 120002307247
JaLCDOI 10.18926/ESR/13959
Title Alternative LISTHKL : List h, k, l, Fo and σFo tables
FullText URL ESR_1_49.pdf
Author Yamakawa, Junji| Kawahara, Akira|
Abstract LISTHKL, a Fortran 77 program listing up the data for deposit is submission to Acta Crystallo-graphica has been written. The program requires a computer set with a printer utilizung the LIPS3 page description language.
Keywords LISTHKL Acta Crystallographica reflection data
Publication Title Okayama University Earth Science Report
Published Date 1994-09-20
Volume volume1
Issue issue1
Start Page 49
End Page 52
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 120002310510
JaLCDOI 10.18926/ESR/13958
Title Alternative CALCOMP to LIPS3 convert library
FullText URL ESR_1_37.pdf
Author Yamakawa, Junji|
Abstract CALLIP, a CALCOMP compatible Fortran 77 library using the Canon LIPS3 page description lan-guage, has been written. As a result, the graphic output of programs with CALCOMP plotting routines used for crystal structure analyses, such as ORTEP2, Rietveld analyses and others can be used under the printer equipped with LIPS3 PDL. The details of the library was given with some graphic examples.
Keywords CALLIP CALCOMP LIPS3 Fortran 77
Publication Title Okayama University Earth Science Report
Published Date 1994-09-20
Volume volume1
Issue issue1
Start Page 37
End Page 48
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 120002310211
JaLCDOI 10.18926/ESR/13957
FullText URL ESR_1_27.pdf
Author Okano, Osamu| Nishiya, Nanayo| Kagami, Hiroo|
Abstract 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.
Keywords chondrule age Rb-Sr isochron Allegan H- chondrite meteorite metamorphism olivine pyroxene
Publication Title Okayama University Earth Science Report
Published Date 1994-09-20
Volume volume1
Issue issue1
Start Page 27
End Page 36
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 120002310261
JaLCDOI 10.18926/ESR/13955
Title Alternative ScSp Phase observed on the Coast of the Seto Inland Sea
FullText URL ESR_1_19.pdf
Author Nishi, Masaki| Oda, Hitoshi|
Abstract Observation of ScSp phase, P wave converted from ScS phase, has been made at a seismological observatory (SBK) located on the coast of the Seto Inland Sea, southwest Japan. The ScSp phases were found on the seismograms of earthqukes with long epicentral distances, but not observed for those with short epicentral distances. Such dependence of appearance of the ScSp phase on epientral distance is interpreted as being due to the Philippine Sea plate horizontally lying beneath the Shikoku and Chugoku districts.
Keywords ScS Phase ScSp Phase Philippine Sea Plate Southwest Japan
Publication Title Okayama University Earth Science Report
Published Date 1994-09-20
Volume volume1
Issue issue1
Start Page 19
End Page 26
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 120002310571
JaLCDOI 10.18926/ESR/13953
FullText URL ESR_1_9.pdf
Author Suzuki, shigeyuki|
Abstract The Iberian Pyrite Belt is an Upper Paleozoic succession which has been divided into the Phyllite-Quartzite Group, the Volcanic-Sliceous Complex and the Culm Group in ascending order from base to the top. The contacts among them are conformable. These Groups are tightly folded and metamorphosed un-der low-grade conditions during Hercynian times. The first stage folds of the Volcanic-Siliceous Complex and the Culm Group are associate with slaty cleavages (S1), while the Phyllite-Quartzite Group is asso-ciate with schistosities (S1). Fold analysis using cleavages and minoe folds has been utilized in the analysis of the stratigraphy. This led to systematic horizontal collection of specimens (pelitic rocks). S1 texture is defined by paralled alignment of secondary platy minerals which tend to grow larger and together, forming zonal domains toward the Phyllite-Quartzite Group. The clay matrices change to recrystallized quartz toward the Phyllite Quartzite Group. Textural modifications are evidenced by gradational changes from slaty cleavages to schistosities. This shows that recrystallization is the important deformation mecha-nism responsible for S1 development. It also reflects that the deformation was contemporaneous with metamorphism.
Keywords Slaty cleavage Schistosity Recrystallization
Publication Title Okayama University Earth Science Report
Published Date 1994-09-20
Volume volume1
Issue issue1
Start Page 9
End Page 18
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 120002310428