Main features of the Hokkaido-Sakhalin fold region geomorphology

Abstract

Several types of landforms are identified within the limits of the Hokkaido-Sakhalin fold region, such as mountain ridges (subdivided into young- Pliocene- linear subparallel and more ancient-Cretaceous-Paleogene-rejuvenated during the Pliocene subtypes, the latter forming complicated dendrite systems). At the Hokkaido Island volcanogenic landforms are widespread and superimposed upon other types. Directions of geomorphic elements are mostly sub-longitudinal or NNW (Sakhalin) and gradually changes into NE and sub-latitudianl (Kurilian) trends near Hokkaido. Within the submerged part of the region the continental shelf is clearly seen (where most of the geomorphic elements identified at the land can be traced) and continental slope, densely dissected with submarine canyons.