Solidification depth and crystallization age of the Shiaidani Granodiorite: Constraints to the average denudation rate of the Hida Range,central Japan |
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| Authors: | Tetsuo Kawakami Shigeru Sueoka Tatsunori Yokoyama Saya Kagami Georgina E King Frédéric Herman Sumiko Tsukamoto Takahiro Tagami |
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| Institution: | 1. Department of Geology and Mineralogy, Graduate School of Science, Kyoto University, Kyoto, Japan;2. Tono Geoscience Center, Japan Atomic Energy Agency, Gifu, Japan;3. Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland;4. Leibniz Institute for Applied Geophysics, Hannover, Germany |
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| Abstract: | Solidification pressure and crystallization age of the ~5 Ma Shiaidani Granodiorite (Hida Mountain Range, central Japan) are determined based on Al-in-hornblende geobarometry and U–Pb zircon dating. Al-poor patchy replacements developed in amphiboles are common in this granite and petrographic study revealed that the replacements include chloritized biotite and albitic plagioclase. These are probably the hydrothermally recrystallized domains, and should not be used for solidification pressure estimates. Magmatic rim of amphibole is characterized by Si < 7.3 a.p.f.u. (AlIV > 0.7 a.p.f.u.), and utilized in solidification pressure estimate that yielded 0.17–0.29 GPa. The solidification age of the granite is estimated as ~5.6–5.2 Ma using U–Pb zircon dating. From these data, the lower limit of an average denudation rate after ~5.6–5.2 Ma for the area where Shiaidani Granodiorite is exposed is estimated as 0.93–2.5 mm/year. |
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| Keywords: | exhumation granite hornblende patchy zoning |
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