Japan Geoscience Union Meeting 2015

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International Session (Oral)

Symbol S (Solid Earth Sciences) » S-IT Science of the Earth's Interior & Techtonophysics

[S-IT07] New constraints on the tectonic evolution of Northeast Asia

Mon. May 25, 2015 11:00 AM - 12:45 PM A03 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Jonny Wu(Department of Geosciences, National Taiwan University), Kyoko Okino(Ocean Research Institute, University of Tokyo), Cedric Legendre(Institute of Earth Sciences, Academia Sinica, Taiwan), Gaku Kimura(Department of Earth and Planetary Science of the Graduate School of Science, The University of Tokyo), Chair:Kenichiro Tani(Department of Geology and Paleontology, National Museum of Nature and Science), Yuan Hsi Lee(Department of Earth and Environmental Sciences, National CHung-Cheng University)

12:30 PM - 12:33 PM

[SIT07-P01] Tectonic evolution of the Philippine Sea: Magnetic data collected during the Japanese continental shelf survey

3-min talk in an oral session

*Kyoko OKINO1 (1.AORI, The University of Tokyo)

Keywords:tectonics, Philippine Sea, magnetic anomaly, backarc basin, arc

Marine magnetic anomalies have been used to date the seafloor, characterize the oceanic crust and reconstruct the evolution process of ocean basins. Japanese continental shelf survey project has collected high-quality, dense magnetic data in the Philippine Sea and the adjacent areas for two decades. The compiled and processed magnetic anomaly data improve our understanding of the tectonic history of the area. Clear magnetic lineation patterns in the Shikoku, Parece Vela basins allow us to elaborate the spreading history of these basins, including the initiation and cessation process of the backarc opening. The anomalies associated with the Kyushu-Palau Ridge also record the transitional phase from arc volcanism to backarc rifting-opening. The West Philippine Basin, Daito Ridges and its intervening small basins, that was formed before the formation of the paleo-IBM arc, show their specific magnetic characteristics. These areas are considered to have moved northward and rotated after their formation. The skewness analysis of magnetic data can provide us some insights about paleo-latitude and/or rotation.