Quaternary System in the Tokachi Plain, East Hokkaido (II)

Landform Evolution and Stratigraphy

Abstract

The stratigraphy and chronology of the Quaternary system in the Tokachi plain, east Hokkaido, have been studied by the present research group since 1962. For the correlation of the topographic surfaces in this plain, several pumice-fall deposits and buried soils were used for as excellent key-beds, viz, in descending order, Eniwa pumice-fall deposit “a”, Shikotsu pumice-fall deposits 1 and 2, orange-colored pumice-fall deposit, chocolate-colored buried soils I, II and III, red palaeosol, and white clay. Their characteristic features were briefly described. The stratigraphic relation between the topographic surfaces and the above key-beds was observed in detail and tabulated as follows:
Topographic surface Key-bed
Some of these surfaces are fans or the like, which extend in the western margin of this plain or the eastern piedmond of Hidaka range and show successive disconformable relations. On the basis of the correlation of the topographic surfaces and Quaternary deposits in this plain, Table 1 is established.