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Paleomagnetism of Miocene Sedimentary Rocks in the Kakegawa Area and Implication for Tectonic Rotation in Central Japan.

1994; Society of Geomagnetism and Earth, Planetary and Space Sciences; Volume: 46; Issue: 12 Linguagem: Inglês

10.5636/jgg.46.1051

2185-5765

Akira Hayashida,

Geology and Paleoclimatology Research

Magnetic measurements have been made on samples from the Kurami and the Saigo Groups in the Kakegawa area, central Japan. Thermal demagnetization experiments reveal that the Matsuba Siliceous Siltstone of the late Early Miocene age preserves two magnetic components, distributed between 150 and 350°C and between 350 and 550°C. The fold test suggests that the low temperature component was acquired after the formation of the syncline, and that the high temperature component is of primary origin. The tilt-corrected direction of the high temperature component shows no significant deflection from the expected direction. Along with the Tomikusa and the Nohi-Yatsuo areas in the north, the Kakegawa area is suggested to have not significantly rotated since 16 Ma, while the clockwise rotation of Southwest Japan occurred at about 15 Ma. The bend of the MTL and the Pre-Neogene basement terranes can be attributed to the relative motion between Southwest Japan and the central part of the Honshu Island in the Miocene.