Tottori Sand-Dune Area, its Geomorphological Description with Evolutional Aspect

Abstract

The writer investigated the sand-dune area near Tottori-shi, where he found many small basins named“Suribachi”(=mortar in English). He inspected the features of these basins and studied their subterranean condition geologically, obtaining the following results.1) There are two types among“Suribachi”: the one has a fountain and the other has no fountain. The former has been a water-welling place befor the accumulation of sand-dune, while the latter is a simple basin which is surrounded by sand-dunes.2) The writer finds out a volcanic-ash beds underneath the sand-dunes. The ash bed occupies a boundary layer between the recent sand-dune and the ancient one. He finds also clay beds directly below the ash bed. These clay beds are thought to be of a sediment in water and will become a key by which the writer can solve the episode from the ancient sand-dune to the recent one.3) The ancient sand-dune is thought to be of a stable dune upon which plants grew. Here and there the writer has found goethite (“Takashi-kozo”in Japanese) among the ancient dune sand.4) Judging from the site of outcrops of a bed rock and sedimentary condition below the sand-dunes, the writer might restore the ancient status as follows: the front of the recent sanddune area has proceeded forwards as far as 500 meters from the front of the ancicnt sand-dune area.