Paleomagnetism of the Shakotan Peninsula, west Hokkaido, Japan

Abstract

A paleomagnetic study was made for Miocene-Pliocene volcanic and sedimentary rocks from the Shakotan Peninsula (43.2°N, 140.5°E). Although most of the sites showed in situ directions coinciding with the direction of the present earth's field (PEF), we did not adopt the usual rejection criterion; the NRM in which the in situ direction is close to the PEF should be automatically rejected. Our opinion is that as long as the original stable remanence is detected there is no need to, rather better not to, reject such NRM directions. To support this idea we compared decay curves of remanence in AF demagnetization among NMR, IRM, and ARM. -from Authors