5:15 PM - 6:30 PM
[SGL36-P01] Paleomagnetic study of Neogene sediments in strike-slip basins along the Tanakura Fault
Keywords:The Tanakura Fault, strike-slip basin, Japan Sea opening, Middle Miocene, paleomagnetic study
Samples for paleomagnetic analyses were collected from the Yajika Rhyorite, Kitatage Formation, Kitatage Formation, Osawaguchi Tuff Member and the Nawashiroda Formation in the Yamatsuri, Western Daigo, Eastern Daigo and Yamagata Basin.
As the results of paleomagnetic analyses, the Kitatage Formation, Osawaguchi Tuff Member, Asakawa Formation and Nantaisan Volcanic Breccia exhibit non-rotating reversed polarity supposed to be correlated to the Chron C5Br (ca. 16.04-15.2 Ma). On the other hand, the Nawashiroda Formation exhibits reversed and normal polarities correlated to the Chrons C5Br, C5Bn, C5ADr (ca.15.2~14.6 Ma) , which associated with a clockwise rotation ca. 20°, suggesting that a counterclockwise rotation ca. -20° is needed to be at this area before deposition of the Nawashiroda Formation.