Japan Geoscience Union Meeting 2015

Presentation information


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)

5:45 PM - 6:00 PM

[SCG57-P33] Deformation process of the Miocene Misaki assemblage at Cape Muroto, Shikoku, Japan

3-min talk in an oral session

*Satoshi TONAI1, Keiji MOURI1 (1.Faculty of Science, Kochi University)

Keywords:accretionary complex, Shimanto belt, Muroto, fault

We report the geologic structure of the Misaki assemblage, which constitutes part of the youngest portion of the Shimanto accretionary complex, Shikoku, Japan. It is interesting to compare the deformation process of this strata with that of the present Nankai accretioary complex. We divided the Misaki assemblage into ten lithofacies, and described lithologic map and geologic cross section of the study area.

The northern part of the study area consists mainly of hemipelagic calcareous mudstone and deformed sandstone and mudstone. In contrast, the southern part of the study area consists of folded turbidite and conglomerate. These strata dip to the west more than 70o and are intruded by Miocene igneous rocks. Many minor faults are observed in the study area.

These lithologic and structural data suggests a deformation process of the Misaki assemblage as follows: (1) deposition of ocean plate stratigraphy, (2) offscraping by frontal thrusts, (3) intrusion of igneous rocks along one of the thrusts, and (4) tilting of the whole strata.