著者

Yuji ICHIYAMA Takahito KOSHIBA Hisatoshi ITO Akihiro TAMURA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.191205, (Released:2020-06-26)

被引用文献数

6

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Early Paleozoic serpentinite melanges in Japan preserve the oldest high–P metamorphic rocks in the circum–Pacific orogenic belt. To understand the tectonic regime at the subduction initiation of the proto–Japan convergent plate boundary, whole–rock geochemistry, and zircon U–Pb geochronology were investigated for amphibolite blocks in the Omi serpentinite mélange, central Japan. The studied amphibolites from two different localities have the mineral assemblage of albite + clinozoisite + amphibole ± rutile ± titanite, which characterize epidote–amphibolite facies metamorphism. Whole–rock trace element concentrations of the amphibolites suggest that gabbroic protoliths formed possibly in an oceanic setting. The zircon U–Pb weighted mean ages obtained from two amphibolite samples indicate that the protolith was formed in the Cambrian. The protolith ages of the studied amphibolites are comparable with those of reported Early Paleozoic ophiolite and high–pressure rocks in Paleozoic serpentinite mélanges in Japan. This fact implies that the young hot oceanic crust was subducting into the East Asian convergent plate margin during the Cambrian.

著者

Akihiro Tamura Takuya Sagawa Kyoko Okino Tomoaki Morishita

出版者

GEOCHEMICAL SOCIETY OF JAPAN

雑誌

GEOCHEMICAL JOURNAL (ISSN:00167002)

巻号頁・発行日

pp.GJ22020, (Released:2022-11-29)

被引用文献数

1

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The whole-rock trace-element compositions of igneous rocks provide primary geochemical information about their petrogenesis. Such compositions can be determined by LA–ICP–MS analysis of fused-glass samples as well as the conventional solution ICP–MS method. However, in contrast to basalt and andesite, the fused-glass method is not suitable for Si-rich rocks (granite and rhyolite) due to the difficulty of making homogeneous glasses. To extend the method to Si-rich rocks, we adopted an MgO dilution process to prepare fused glasses and evaluated the technique by analysis of granite and rhyolite reference materials. Dilution of 30 mg of powdered samples with 10 mg MgO facilitated the preparation of homogeneous fused-glass samples of felsic rocks. LA–ICP–MS analyses indicate that the fused glass is homogeneous in the contents of most incompatible elements considered in igneous petrology. The glass enables the analysis of these elements in felsic rocks within 20% deviation from reference data. The sample data are consistent with reference values for rhyolite although Zr and Hf data deviate significantly (by ~40%) from reference values for granitic rocks.

著者

Kiyokazu Akasaka Akihiro Tamura Aoi Katsuta Ayako Sagawa Takahiro Otsudo Yu Okubo Yutaka Sawada Toby Hall

出版者

The Society of Physical Therapy Science

雑誌

Journal of Physical Therapy Science (ISSN:09155287)

巻号頁・発行日

vol.29, no.12, pp.2147-2150, 2017 (Released:2017-12-07)

参考文献数

23

被引用文献数

4

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[Purpose] To determine whether repetitive trampoline or hard surface jumping affects lower extremity alignment on jump landing. [Subjects and Methods] Twenty healthy females participated in this study. All subjects performed a drop vertical jump before and after repeated maximum effort trampoline or hard surface jumping. A three-dimensional motion analysis system and two force plates were used to record lower extremity angles, moments, and vertical ground reaction force during drop vertical jumps. [Results] Knee extensor moment after trampoline jumping was greater than that after hard surface jumping. There were no significant differences between trials in vertical ground reaction force and lower extremity joint angles following each form of exercise. Repeated jumping on a trampoline increased peak vertical ground reaction force, hip extensor, knee extensor moments, and hip adduction angle, while decreasing hip flexion angle during drop vertical jumps. In contrast, repeated jumping on a hard surface increased peak vertical ground reaction force, ankle dorsiflexion angle, and hip extensor moment during drop vertical jumps. [Conclusion] Repeated jumping on the trampoline compared to jumping on a hard surface has different effects on lower limb kinetics and kinematics. Knowledge of these effects may be useful in designing exercise programs for different clinical presentations.