研究者詳細 - 淺原　良浩

論文 - 淺原　良浩

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Investigation of rare earth elements (REEs) as exploration potential in intrusive bodies in the northern Sanandaj-Sirjan zone (Kurdistan area), western Iran 査読有り国際共著国際誌

Azizi, H., Maghsoudloo, A., Nouri, F., Asahara, Y., Yamamoto, K., Minami, M., Tsuboi, M.

Geochemical Journal 54 巻 ( 4 ) 頁： 221 - 232 2020年8月

A chronological and geochemical study of the Tadamigawa older-stage granites: igneous activity in the west of the Tanakura Tectonic Line (TTL) of northeastern Japan 査読有り国際誌

Wakasugi, Y., Wakaki, S., Tanioka, Y., Ichino, K., Tsuboi, M., Asahara, Y., Noda, A.

Geochemical Journal 54 巻 ( 4 ) 頁： 203 - 220 2020年8月

Variability of protoliths and pressure-temperature conditions of amphibolites from the Ohmachi Seamount (Izu-Bonin-Mariana arc): evidence of a fossil subduction channel in a modern intra-oceanic arc 査読有り国際誌

Imayama, T., Ueda, H., Usuki, T, Minami, M., Asahara, Y., Nagahashi, T.

Mineralogy and Petrology 114 巻頁： 305 - 318 2020年8月

Integrated Neogene biochemostratigraphy at DSDP Site 296 on the Kyushu-Palau Ridge in the western North Pacific 査読有り国際誌

Matsui, H., Horikawa, K., Chiyonobu, S., Itaki, T., Ikehara, M., Kawagata, S., Wakaki-Uchimura, H., Asahara, Y., Seki, O., Okazaki, Y.

Newsletters on Stratigraphy 53 巻頁： 313 - 331 2020年6月

Detrital Sr-Nd isotopes, sediment provenances and depositional processes in the Laxmi Basin of the Arabian Sea during the last 800 ka 査読有り国際共著国際誌

Khim, B.K., Horikawa, K., Asahara, Y., Kim, J.E, Ikehara, M.

Geological Magazine 157 巻頁： 895 - 907 2020年6月

Anatomy of the magmatic plumbing system of Los Humeros Caldera (Mexico): implications for geothermal systems 査読有り国際共著国際誌

Lucci, F., Carrasco-Núñez, G., Rossetti, F., Theye, T., White, J.C., Urbani, S., Azizi, H., Asahara, Y., Giordano, G.

Solid Earth 11 巻頁： 125 - 159 2020年1月

Petrogenesis and geodynamic implications of an Ediacaran (550Ma) granite complex (metagranites), southwestern Saqqez, northwest Iran 査読有り国際共著国際誌

Daveshvar, N., Maanijou, M, Azizi, H., Asahara, Y.

Journal of Geodynamics 132 巻頁： 101669 2019年12月

Late Paleocene adakitic granitoid from NW Iran and comparison with adakites in the NE Turkey: Adakitic melt generation in normal continental crust 査読有り国際共著国際誌

Azizi, H, Stem, R.J, Topuz, G, Asahara, Y, Moghadam, H.S.

Lithos 346 巻頁： 105151 2019年11月

Common occurrence of calcic plagioclase in granitoids from Mt. Kaizuki area, central Japan 査読有り国際共著国際誌

Hong Mei, Enami, M, Tsuboi, M, Asahara, Y

Journal of Mineralogical and Petrological Sciences 114 巻 ( 4 ) 頁： 201 - 213 2019年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japan Association of Mineralogical Sciences

<p>Calcic plagioclase with anorthite (An) content of up to 91% commonly occurs in coexistence with the sodic phase (An<sub><40–50</sub>) in the Cretaceous Kaizuki–yama (Mt. Kaizuki) granitoid body that intrudes into the Mino belt of the Jurassic accretionary sediment complex in central Japan. The Kaizuki–yama granitoids are mainly composed of plagioclase, K–feldspar, quartz, and biotite with subordinate amounts of amphibole, ilmenite, and apatite. The sodic plagioclase grains show common igneous–type normal zoning with decreasing anorthite content toward the rim. In most cases, the calcic plagioclase occurs as a crystal core, which is discontinuously surrounded by a sodic mantle. The calcic parts rarely show fine and nebular texture with sodic domains; however, a thin calcic zone (100–150 µm in width) develops along the boundary between the nebular core and the sodic mantle. In the nebular core, calcic plagioclase sometimes rims the fine–grained calcite, prehnite, and zoisite/epidote (less than 10–20 µm in size). Most amphibole grains have ferropargasite/ferrohornblende compositions and are usually rimmed by secondary ferro–actinolite. Although the pressure/temperature conditions estimated based on amphibole–plagioclase equilibria vary widely between samples, they show systematic decreases in pressure with decreasing temperature from 0.5 GPa/800 °C to approximately 0.2 GPa/700 °C. Some anorthite–rich plagioclase grains may have been xenocrystic and/or antecrystic in origins, and others were crystallized from calcic part of locally heterogeneous magma. The incorporation of calcic plagioclase into the felsic magma and the locally calcic environment probably resulted from the assimilation of skarn and related calcareous rocks consisting of the wall rocks of the Kaizuki–yama body during magmatic intrusion and solidification.</p>

DOI： 10.2465/jmps.190118

Web of Science

Litho-, bio-, and chemostratigraphy of the Middle Triassic carbonate succession in the North-Central Coast Region of Vietnam 査読有り国際共著国際誌

Thuy Thi Nhu Ha, Takayanagi, H., Ueno, K., Asahara, Y., Yamamoto, K., Iryu, Y.

Progress in Earth and Planetary Science 6 巻頁： 47 2019年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer

Middle Triassic carbonates extend from the North-Central Coast region of Vietnam to northern Laos. We conducted sedimentological, paleontological, and geochemical analyses on the carbonates of the Hoang Mai Formation in Nghe An province, Vietnam. The carbonates consist of the following six lithostratigraphic units (from bottom to top): sandy limestone (unit 1), peloidal packstone with a microbialite interlayer (unit 2), peloidal packstone and oncoidal floatstone (unit 3), peloidal–bioclastic packstone (unit 4), peloidal packstone with variable quantities of bioclasts and microbialite (unit 5), and peloidal packstone with variable quantities of bioclasts (unit 6). The sandy nature of unit 1 and of three of the interlayers in unit 2 indicates a supply of terrigenous material during the early stages of formation of the Hoang Mai carbonate platform. The dominance of carbonates with a fine-grained matrix throughout the overlying succession implies a low-energy depositional environment. Common occurrences of dasycladalean algae in units 4–6 indicate a back-reef lagoon environment. A total of 24 foraminiferal taxa, including Citaella dinarica and C. deformata, were identified. These two age-diagnostic species occur in units 3–6, suggesting that this interval is correlated with the Pelsonian and that the lower units (units 1–2) are potentially correlated with the Bithynian. Thus, the entire core section can be assigned to the middle Anisian (lower Middle Triassic). An assessment of the diagenetic alteration using geochemical parameters indicates that the carbonates of the studied succession have not retained their initial strontium (87Sr/86Sr) and oxygen (δ18O) isotope compositions. In contrast, the carbonates in the lower (units 1–2) and middle (units 2–5) intervals have retained their initial carbon isotope compositions (δ13C), making them suitable for C isotopic analyses. In the lower interval, we observe a slight δ13C-enrichment, followed by a gradual δ13C-depletion upwards into the middle interval. The observed trend in δ13C values from the Hoang Mai Formation can be correlated with similar trends reported from South China and Romania. Samples within the upper interval (units 5–6) of the Vietnamese δ13C profile are relatively δ13C-depleted, which is likely the result of diagenetic overprinting.

DOI： 10.1186/s40645-019-0293-y

Web of Science

Multiphase magma intrusion, ore-enhancement and hydrothermal carbonatisation in the Siah-Kamar porphyry Mo deposit, Urumieh-Dokhtar magmatic zone, NW Iran 査読有り国際共著国際誌

Ahmad, R., Rossetti, F., Tech, F., Asahara, Y., Azizi, H., Glondny, J., Lucci, F., Nozaem, R., Opitz, J., Selby, D.

Ore Geology Reviews 110 巻頁： 102930 2019年7月

Petrogenesis of the Harisn-Sahneh serpentinized peridotite along the Zagros suture zone, western Iran: New evidence for mantle metasomatism 査読有り国際共著国際誌

Nouri, F., Asahara, Y., Azizi, H., Tsuboi, M.

Geological Magazine 156 巻 ( 5 ) 頁： 772 - 800 2019年5月

Sr-87/Sr-86 age determination by rapidly formed spherical carbonate concretions 査読有り国際共著国際誌

Yoshida, H., Asahara, Y., Yamamoto, K., Katsuta, N., Minami, M., Metcalfe, R.

Scientific Reports 9 巻頁： 1003 2019年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature Publishing Group

Isolated spherical carbonate concretions are frequently observed in finer grained marine sediments of widely varying geological age. Recent studies on various kinds of spherical carbonate (CaCO3) concretions revealed that they formed very rapidly under tightly constrained conditions. However, the formation ages of the isolated spherical carbonate concretions have never been determined. Here we use Sr-87/Sr-86 ratios to determine the ages of these spherical concretions. The studied concretions formed in the Yatsuo Group of Miocene age in central Japan. Some formed post- mortem around tuskshells (Fissidentalium spp.), while other concretions have no shell fossils inside. The deformation of sedimentary layers around the concretions, combined with geochemical analyses, reveal that Sr was incorporated into the CaCO3 concretions during their rapid formation. Strontium isotopic stratigraphy using Sr-87/Sr-86 ratios of all concretions indicates an age of 17.02 +/- 0.27 Ma, with higher accuracy than the ages estimated using micro- fossils from the Yatsuo Group. The results imply that the Sr-87/Sr-86 ratio of isolated spherical carbonate concretions can be applied generally to determine the numerical ages of marine sediments, when concretions formed soon after sedimentation. The Sr-87/Sr-86 age determinations have high accuracy, even in cases without any fossils evidence.

DOI： 10.1038/s41598-019-38593-9

Web of Science

Age, geochemistry and emplacement of the ~40-Ma Baneh granite-appinite complex in a transpressional tectonic regime, Zagros suture zone, northwest Iran 査読有り国際共著国際誌

Azizi, H., Haddad, S., Stern, R.J., Asahara, Y.

International Geology Review 61 巻 ( 2 ) 頁： 195 - 223 2019年1月

Fe-oxide concretions formed by interacting carbonate and acidic waters on Earth and Mars 査読有り国際共著国際誌

Yoshida, H., Hasegawa, H., Katsuta, N., Maruyama, I., Sirono, S., Minami, M., Asahara, Y., Nishimoto, S., Yamaguchi, Y., Ichinnorov, N., Metcalfe, R.

Science Advances 4 巻頁： eaau0872 2018年12月

Geochemical interpretation of magnesium and oxygen isotope systematics in granites with the REE tetrad effect 査読有り国際共著国際誌

Lee, S.G., Ahn, I., Asahara, Y., Tanaka, T., Lee, S.R.

Geosciences Journal 22 巻 ( 5 ) 頁： 697 - 710 2018年10月

Late Miocene-mid-Pliocene tectonically induced formation of the semi-closed Japan Sea, inferred from seawater Nd isotopes 査読有り国際誌

Yukiko Kozaka, Keiji Horikawa, Yoshihiro Asahara, Hiroshi Amakawa, Yusuke Okazaki

Geology 46 巻 ( 10 ) 頁： 903 - 906 2018年9月

Zircon U-Pb dating, geochemistry and evolution of the Late Eocene Saveh magmatic complex, central Iran: Partial melts of sub-continental lithospheric mantle and magmatic differentiation 査読有り国際共著国際誌

Nouri, F., Azizi, H., Stern, R.J., Asahara, Y., Khodaparast, S., Madanipour, S., Yamamoto, K.

Lithos 314-315 巻頁： 274 - 292 2018年8月

Petrogenesis and geochronology of Mishao peraluminous I-type granites, Shalair valley area, NE Iraq 査読有り国際共著国際誌

Abdulzahra, I.K., Hadi, A., Asahara, Y., Azizi, H., Yamamoto, K.

Chemie der Erde 78 巻頁： 215 - 227 2018年5月

The Late Jurassic Panjeh submarine volcano in the northern Sanandaj-Sirjan Zone, northwest Iran: Mantle plume or active margin? 査読有り国際共著国際誌

Azizi, H., Lucci, F., Stern, R.J., Hasannejad, S., Asahara, Y.

Lithos 308-309 巻頁： 364 - 380 2018年5月

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