Japan Geoscience Union Meeting 2015

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Symbol S (Solid Earth Sciences) » S-CG Complex & General

[S-CG57] Structure, evolution and dynamics of mobile belts

Wed. May 27, 2015 4:15 PM - 6:00 PM A06 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Toru Takeshita(Department of Natural History Sciences, Graduate School of Science, Hokkaido University), Hiroshi Sato(Earthquake Prediction Research Center, Earthquake Research Institute, The University of Tokyo), Koichiro Obana(Research and Development Center for Earthquake and Tsunami, Japan Agency for Marine-Earth Science and Technology), Takuya NISHIMURA(Disaster Prevention Research Institute, Kyoto University), Yukitoshi Fukahata(Disaster Prevention Research Institute, Kyoto University), Aitaro Kato(Graduate School of Environmental Studies, Nagoya University), Jun Muto(Department of Earth Sciences, Tohoku University), Katsushi Sato(Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University), Shuichi Kodaira(Institute for Research on Earth Evolution Japan Agency for Marine-Earth Science and Technology), Takeshi Sagiya(Disaster Mitigation Research Center, Nagoya University), Tatsuya Ishiyama(Earthquake Research Institute, University of Tokyo), Makoto MATSUBARA(National Research Institute for Earth Science and Disaster Prevention), Yasutaka Ikeda(Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo), Chair:Bunichiro Shibazaki(International Institute of Seismology and Earthquake Engineering, Building Research Institute)

5:15 PM - 5:18 PM

[SCG57-P17] Detrital zircon chronology of the Upper Cretaceous Atokura Formation in northern Kanto Mtn., Japan

3-min talk in an oral session

*Hiroki NAKAHATA1, Yukio ISOZAKI2, Kazuo KOSAKA3, Shuhei SAKATA4, Takafumi HIRATA4 (1.Department of Earth and Planetary Science, Graduate School of Science, The Univeristy of Tokyo, 2.Department of Earth Science and Astronomy, The University of Tokyo, 3.Department of Geosystem Sciences, College of Humanities and Sciences, Nihon University, 4.Graduate school of Science, Kyoto University)

Keywords:Cretaceous, sandstone, detrital zircon, U-Pb age, LA-ICP-MS, Japan

The Cretaceous sandstones of the Atokura nappe in the northern Kanto Mtns. in central Japan were analyzed for detrital zircon U-Pb chronology by LA-ICP-MS. The results documented two distinct age groups; i.e., 150-300 Ma (Permian to Jurassic) and 1600-2600 Ma (Neoarchean to Mesoproterozoic). As there are no correlative candidates for provenance in the neighborhood, the Cretaceous strata of the Atokura nappe were likely exotic. The occurrence of Jurassic granitoids is currently limited to the Hida belt in central Japan, while no Precambrian basement is exposed at all in Japan. Judging from the allochthonous mode of occurrence, the Atokura nappe was derived originally from the back-arc domain of the Cretaceous Japan.