JaLCDOI | 10.18926/ESR/56691 |
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Title Alternative | Non-calcareous beachrock found in Akagurisaki, Ohi Town, Fukui Prefecture |
FullText URL | esr_025_001_005.pdf |
Author | Suzuki, Shigeyuki| Azuma, Yoichi| Deyama, Yasuyo| Yukawa, Hirokazu| Usui, Mayumi| |
Abstract | Beachrock which was formed about 0.5 meter higher than high tide is found in Akagurisaki, Ohi Town, Fukui Prefecture. The outcrops always get wet by spring water. The sediments are composed of well sorted rounded gravels and sands but calcareous shell is not found at all. Intergranular space is occupied by white amorphous cement. Magnesium and silicon rich composition of the cement is obtained by EPMA analysis. There is a conjecture that the magnesium rich cement was precipitated in spite of solution of calcareous shell under saturated state by spring water, because calcium has a higher tendency to ionize than magnesium. |
Keywords | Beachrock Akagurisaki non-calcareous cement ionization tendency |
Publication Title | Okayama University Earth Science Report |
Published Date | 2018-12-27 |
Volume | volume25 |
Issue | issue1 |
Start Page | 1 |
End Page | 5 |
ISSN | 1340-7414 |
language | Japanese |
Copyright Holders | © 2018 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
File Version | publisher |
JaLCDOI | 10.18926/ESR/56694 |
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FullText URL | esr_025_031_038.pdf |
Author | Amano, Hideki| Suzuki, Shigeyuki| Sato, Masaru| Yanagida, Makoto| |
Abstract | The study area is situated in Japan Sea side margin of the Shakotan Peninsula, Hokkaido, Japan, where MIS5e Terrace is preserved along the cost. Numbers of tight drilling have done to establish new method for terrace analysis. Buried wave cut terrace and sea cliff (when the MIS5e Terrace was formed) are reconstructed by distribution of the terrace deposits and these bottom of unconformity planes. The precise site and altitude of former shoreline was also obtained. Altitudes of the former shoreline from the 7 sections are almost the same 22 to 27m in height. Previous data of the height of shoreline are obtained from the topographic MIS5e Terrace surface. The altitudes have variation from 30m to 60m. It suggests that the traditional method for the MIS5e terrace analysis had some errors in the study area. |
Keywords | MIS5e marine terrace terrace deposits tight drilling shoreline |
Publication Title | Okayama University Earth Science Report |
Published Date | 2018-12-27 |
Volume | volume25 |
Issue | issue1 |
Start Page | 31 |
End Page | 38 |
ISSN | 1340-7414 |
language | English |
Copyright Holders | © 2018 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
File Version | publisher |
JaLCDOI | 10.18926/ESR/56695 |
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FullText URL | esr_025_039_048.pdf |
Author | Knittel, Ulrich| Walia, Monika| Suzuki, Shigeyuki| Lee, Yuan-Hsi| |
Abstract | The high-P/low-T Sanbagawa Metamorphic Belt that traverses SW Japan, has been subdivided into two belts thought to have been metamorphosed at ca. 120 Ma and at ca. 65 Ma (‘Sanbagawa Metamorphic Rocks’ and ‘Shimanto Metamorphic Rocks’). The subdivision was based on the assumption that metamorphism occurred at ca. 116 Ma, largely based on an early Rb-Sr isotope study and zircon data obtained for the eclogite unit of the Sanbagawa Belt, whereas in some parts of the belt detrital zircons of late Cretaceous age (90-80 Ma) were discovered. Analysis of detrital zircons sampled from two sites within the area considered to expose the older ‘Sanbagawa Metamorphic Rocks’, including the area investigated by the Rb-Sr study, reveals the presence of zircons younger than 95 Ma in all samples and some grains as young as 80 ± 4 Ma. It is therefore concluded that the Sanbagawa Belt is one single tectonic entity that formed in the Late Cretaceous though it contains older components, including fossiliferous clasts, older basic meta-volcanics and eclogite units that may record earlier metamorphic events. |
Keywords | U-Pb zircon dating Sanbagawa Metamorphic Belt Late Cretaceous Asemi River |
Publication Title | Okayama University Earth Science Report |
Published Date | 2018-12-27 |
Volume | volume25 |
Issue | issue1 |
Start Page | 39 |
End Page | 48 |
ISSN | 1340-7414 |
language | English |
Copyright Holders | © 2018 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
File Version | publisher |
Title Alternative | Bulletin of Archaeological Research Center Okayama University 2017 |
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FullText URL | 紀要2017.pdf |
Author | Nozaki, Takahiro| Minami, Kentaro| Yamamoto, Etsuyo| Suzuki, Shigeyuki| Yamaguchi, Yuji| Iwasaki, Shiho| 古環境センター| 吉田生物研究所| |
Publication Title | 岡山大学埋蔵文化財調査研究センター紀要 |
Published Date | 2019-03-29 |
Volume | volume2017 |
language | Japanese |
Copyright Holders | Archaeological Research Center, Okayama University |
File Version | publisher |
Pages | v, 96 p. |
JaLCDOI | 10.18926/ESR/58575 |
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Title Alternative | Schistose fault related rocks from the Sangun Metamorphic Rocks, Kawakita area, Misaki Town, Okayama Prefecture, SW Japan |
FullText URL | esr_026_019_024.pdf |
Author | MATSUSHITA, Mirei| SUZUKI, Shigeyuki| |
Abstract | The crystalline schist which is representatively exposed in the Innerside of Southwest Japan is called the Sangun Metamorphic Rocks (SMR). In Kawakita area, Misaki Town, Okayama Prefecture, schistose fault rocks which is newly described in below are intercalated in the SMR. The rocks are composed of lenticular fragments of pelitic, basic siliceous rocks and quartz vein with siliceous to pelitic matrix. The fine-grained muscovites which define schistosity penetrate the rocks. Major direction of layer which though to reflect slip plane is subparallel to the schistosity. The long axis of some fragments are slightly oblique to the schistosity. The combination of the two sets of planes is considered to be a composite planar fabric. These occurrences suggest that the rocks are fault rock before the Sangun Metamorphism and named as schistose fault rocks. Lenses of cataclasite and myronite are accompanied. Planar thin (about 10cm in thickness) brittle fault rock is also associated. These shear deformed rocks form units of layer (shear zone) of 10 to 100m in thickness, and are concordantly intercalated in the surrounded normal schists. Active periods of the shear zones had several times from before and after the event of the Sangun Metamorphism. |
Keywords | Sangun Metamorphic Rocks regional metamorphism shear deformation schistose fault rock |
Publication Title | Okayama University Earth Science Report |
Published Date | 2019-12-27 |
Volume | volume26 |
Issue | issue1 |
Start Page | 19 |
End Page | 24 |
ISSN | 1340-7414 |
language | Japanese |
Copyright Holders | © 2019 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
File Version | publisher |
JaLCDOI | 10.18926/ESR/61955 |
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Title Alternative | The Kibi Plateau Surface ― relationship with the Paleogene and Miocene deposits in middle western part of Okayama Prefecture, Japan ― |
FullText URL | esr_027_019_027.pdf |
Author | Tanaka, Hajime | Suzuki, Shigeyuki| |
Abstract | The Kibi Plateau Surface is associated with the Paleogene gravel river bed deposits of the Kibi Group and the Miocene marine deposits of the Katsuta Group and the Bihoku Group. These Paleogene and Miocene units are valley fill deposits. The Kibi Group is composed of formations which is deposited by more than 7 different depositional events during earliest to latest Paleogene Period. Repeated cycles of “erosion - formation of new valley system - deposition and fill up the valley” created the low relief topographic surface. The deposition of the Miocene deposits might complete the Kibi Plateau Surface. Detailed field works have done in middle western part of Okayama Prefecture. The Kibi Plateau Surface in study area is gently dipping from NW (about 600m high) to SE (about 100m high). The distributions of the Paleogene and Miocene deposits fit the surface. At the southern margin of the Kibi Plateau, the surface is a little inclined (from 400m high to 100m high) where the bottom of paleo-valleys of the Paleogene deposits are subparallel to the surface. It suggests that the gentle tilting of the Kibi Plateau is caused by an up-warping. |
Keywords | Kibi Plateau Surface Paleogene Neogene Miocene |
Publication Title | Okayama University Earth Science Report |
Published Date | 2021-03-31 |
Volume | volume27 |
Issue | issue1 |
Start Page | 19 |
End Page | 27 |
ISSN | 1340-7414 |
language | Japanese |
Copyright Holders | © 2021 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
File Version | publisher |
NAID | 120007037376 |
JaLCDOI | 10.18926/ESR/63514 |
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Title Alternative | Depositional history of the Paleogene to Neogene valley fill deposits and topographic change in the Kibi Plateau region, Okayama City, Southwest Japan |
FullText URL | esr_028_001_025.pdf |
Author | Tanaka, Hajime| Suzuki, Shigeyuki| |
Keywords | Kibi Plateau Surface Paleogene Kibi Group Miocene Bihoku Group |
Publication Title | Okayama University Earth Science Report |
Published Date | 2022-03-31 |
Volume | volume28 |
Issue | issue1 |
Start Page | 1 |
End Page | 25 |
ISSN | 1340-7414 |
language | Japanese |
Copyright Holders | © 2022 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
File Version | publisher |
JaLCDOI | 10.18926/ESR/66846 |
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FullText URL | esr_030_021_035.pdf |
Author | MAURER, Robert| HARKER, Stuart| SUZUKI, Shigeyuki| WHEELER, Allan| |
Abstract | Mantle convection currents are the currently accepted driving force for plate tectonics that have ripped apart the continents and created oceans. Because of these actions, continental collisions and ocean closures have resulted. Our paper challenges the conventional concept and provides an alternate, mathematically justified drive mechanism. The pull-push motions of such convection currents in the upper mantle are here concluded to be too weak to be the driving mechanism. Our proposal for such global scale forces concerns the effect of an offset centre of mass of the Earth that results in rotational wobbling. Kepler’s laws of planetary motion demonstrate the rotational behavior of the Earth to be aligned with the Sun on the outward and inward motions of the elliptical orbit. The unbalanced rotation on a fixed gravitational axis results in circumferential stresses on the outer Earth’s rim that is more than strong enough to pull the continental plates apart. The proposed unbalanced rotational stress force equation is shown to be sufficient to drive the cyclic breakup and reassembly of the continental plates, as well as the generation of new oceanic crust and subduction zones. Mantle convection currents are here demonstrated to have a passive rather than active role in the plate movements. |
Keywords | Differential circumferential tensile force Rotating Earth Offset centre of mass radius of eccentricity |
Publication Title | Okayama University Earth Science Report |
Published Date | 2024-03-31 |
Volume | volume30 |
Issue | issue1 |
Start Page | 21 |
End Page | 35 |
ISSN | 1340-7414 |
language | English |
Copyright Holders | © 2024 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
File Version | publisher |