JpGU-AGU Joint Meeting 2017

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[JJ] Oral

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

[S-CG73] [JJ] Petrology, Mineralogy and Resource Geology

Mon. May 22, 2017 3:30 PM - 5:00 PM A08 (Tokyo Bay Makuhari Hall)

convener:Satoshi SAITO(Graduate School of Science and Engineering, Ehime University), Koichi Momma(National Museum of Nature and Science), Tatsuo Nozaki(Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology), Nobutaka Tsuchiya(Department of Geology, Faculty of Education, Iwate University), Chairperson:Nobutaka Tsuchiya(Department of Geology, Faculty of Education, Iwate University), Chairperson:Satoshi Saito(Graduate School of Science and Engineering, Ehime University)

4:30 PM - 4:45 PM

[SCG73-10] Petrochemistry and U-Pb zircon geochronology of felsic rocks from the Kagura complex, south Kitakami Mauntains, Japan

*Nobutaka Tsuchiya1, Tatsuro Adachi2, Nobuhiko Nakano2, Yasuhito Osanai2 (1.Department of Geology, Faculty of Education, Iwate University, 2.Department of Earth Sciences, Faculty of Social and Cultural Studies, Kyushu University)

Keywords:zircon geochronology, Kitakami Mountains, Cambrian

Basement rocks of the South Kitakami belt are distributed in Hayachine to Miyamori area, and is called Hayachine complex. Petrochemistry and U-Pb zircon geochronology were investigated from felsic rocks in the Kagura complex associated with Hayachine complex. U-Pb dating of zircons were carried out using Agilent 7500cx quadrupole inductively coupled plasma mass spectrometer (ICP-MS) with a New Wave Research UP-213 Nd-YAG UV (213 nm) laser ablation system (LA) installed at the Kyushu University (Adachi et al., 2012). Zircon grains from the tonalite define a concordant age of 494+/-4Ma (n=18) and 487+/-4Ma (n=26), and from the quartz diorite define a concordant age of 500+/-4Ma (n=19). These data suggests that age of the Hayachine complex could become older ca. 500Ma. Moreover, granitic activity in early Paleozoic in proto-Japan occurs at ca. 500 Ma and ca. 450 Ma.