2002 Volume 41 Issue 1 Pages 45-51
This study clarified the tephrochronology of late Pleistocene to Holocene strath terraces younger than approximately 50ka, based on their geomorphologic configuration between marker tephra and terraces, that are distributed between the Kakinoki and Suhara districts of the Aburuma River, central east margin of the Niigata Basin, central Japan. Six levels of strath terraces (Ab-I, Ab-II, Ab-III, Ab-IV, Ab-V and Ab-VI) have developed and four tephra ashes (Ab-t4, Ab-t3, Ab-t2 and Ab-t1) have fallen since approximately 50ka. Ab-t2 can be correlated with the widespread tephra As-K (Asama-Kusatsu, 13ka), Ab-t3 with AT (Aira-Tanzawa, 25ka) and Ab-t4 with DKP (Daisen Kurayoshi, 50ka). Ab-t1 is thought to have fallen after 13ka. Only the Ab-II Terrace distributed locally in the upper reaches was formed by the primary movement of the Higashinomyo landslide approximately 50ka.