人類学・考古学のための磁気年代学

日本におけるその現状展望

抄録

It is essential for the magnetic dating of archaeological remains and sites that the changes in geomagnetic elements are known with regard to the relevant period in the past. Secular variation curves of the direction of geomagnetism in historic and protohistoric times in Japan have been set up by means of the natural remanent magnetism of baked earth from ceramic kilns, lava flows and tuffs, the absolute dates of them being determined by archaeological and documentary evidences. As to the Yayoi and Jomon period, charcoal was occasionally found from the dwelling pit where baked earth samples were collected so that the radiocarbon date determined from the charcoal was directly connected with the geomagnetic direction obtained from the baked earth. Change in the intensity of geomagnetism in the past has also been traced back into the Jomon period. Magnetic dating may be achieved more effectively, if the change in the intensity is taken into account together with that in the direction of geomagnetism.