最終氷期の地磁気変化  [in Japanese] Geomagnetic variation during the last glacial age  [in Japanese]

The Late Pleistocene sedimentary cores were taken from marshy land and lowland near the northwestern shore of Lake Inawashiro, Northeast Japan. Stratigraphic correlation of the cores is based on distinctive horizons of tephralayers and upon established pollen zones. The detrital remanent magnetization of these cores has been measured. Alternating field demagnetization in peak fields up to 15 mT were necessary for the removal of unstable secondary magnetization components. The longest core from the Hoshojiri Moor recorded four geomagnetic excursions. Extrapolation of ^<14>C dates suggest that the uppermost Inawashiro I Excursion occurred between 14,000 and 17,000 years B.P., and the lower Inawashiro II, III and IV excursions occurred during approximately 35,000-48,000 years B.P.