Paleoniagnetism Study of Pliocene to Pleistocene Volcanic Rocks in Southwest Japan

The directions of natural remanent magnetization of about 300 volcanic rock specimens collected from Sovthwest,Japan of which ages range from Plioccne to Pleistocenc werc measured• The mean pole positions calculated from the results agree with the present geographic north pole within an oval of 9591o confidence.This fact suggests that there were no considerable movement of paleomagnetic pole position during Pliocene and Pleistocene in Sourhwest Japan, and that Southwest Japan did not change its geographical situation since Pliocene epoch.Furthetmore. the volcanic rocks ofrembte localities used in the study can be correlated much more exactly with one anQther by the aid ofcomprehensive knowledges, such as their stratigraphy, absolute age determined by isotope method and the paleomagnetic polarity change of their remanent magnetization.