Large tectonic movement of the Japan Arc in late Cenozoic times inferred from paleomagnetism: Review and synthesis

Abstract

Paleomagnetic studies facilitate an understanding of the evolution of the Japan Arc in Cenozoic times from the perspective of tectonic movement. The Japan Arc rifted from the Asian continent in the middle Miocene, while East Asia, including the Japan Arc, moved northward at the same time. The rifting phenomenon of the Japan Arc is described by differential rotation of Southwest and Northeast Japan. Southwest Japan was rotated clockwise through about 45" and Northeast Japan was rotated counter-clockwise through about 40". This differential rotation occurred concurrently at about 15 Ma. Eighty percent of the rotation was completed during a period of 1.8 million years. These factors lead us to propose a 'double door' opening mode with a fast spreading rate of 21 cm/yr for the evolution of the Japan Sea, suggesting that the asthenosphere with a low viscosity was injected beneath the Japan Sea area. The large northward motion of East Asia in relation to Europe is expected from the apparent polar wander path constructed from the paleomagnetic data of the Japan Arc. East Asia may have moved northward by more than 1700 km between 20 Ma and 10 Ma accompanied by a slightly clockwise rotation of 10". The eastern part of the Eurasian plate was subjected to extreme geodynamic conditions in late Cenozoic times.

Geochronology and geochemistry of Late Cretaceous–Paleocene granitoids in the Sikhote-Alin Orogenic Belt: Petrogenesis and implications for the oblique subduction of the paleo-Pacific plate

“…The paleomagnetic data have been used to suggest that the landmass of SW Japan underwent clockwise rotation and thus must have separated from the Russian Far East (Otofuji, 1996). However, this interpretation is inconsistent with the basement rocks having the affinity with the Cathaysia Block in South China (vs. the anticipated North…”

Reconstruction of northeast Asian deformation integrated with western Pacific plate subduction since 200 Ma

“…Paleomagnetic evidence has demonstrated opposite rotations for southwestern and northeastern Japan (e.g., Kawai et al, 1961;Otofuji, 1996;Hoshi and Yokoyama, 2001). SW Honshu and northern Kyushu consistently rotated clockwise.…”

Miocene clockwise rotation of southwest Japan and formation of curvature of the Median Tectonic Line: Paleomagnetic implications

“…Later paleomagnetic studies established that SW Japan experienced clockwise rotation in Miocene times [e.g., Otofuji, 1996 …”