A PECULIAR PROCESS OF SULPHUR DEPOSITION 



Y. OINOUYE 



Imperial Tohoku University, Sapporo, Japan 



The sulphur deposits of Japan have four different modes of 

 origin: sublimation, impregnation, flow, and deposition in lakes. 

 They are all doubtless of solfataric origin. The first two types are 

 common everywhere around volcanic craters, but flows of sulphur 

 are found, so far as the writer knows, only at Rausu, Hokkaido, and 

 Tsurugisan, Rikuchu. 



The lake type is very peculiar and unusual. Most of the 

 productive sulphur mines of Japan are operated in deposits which 

 are nearly circular in outline. Some of them which are stratified 

 attain a thickness of 30 meters, and are overlaid by fine brown 

 clayey or tufaceous substances which were derived partly from the 

 surrounding rocks and partly from the sulphur itself. 



The characteristic topography of the majority of these Japanese 

 sulphur beds clearly shows that they were formed by deposition 



from crater lakes. The method 

 of formation, however, appears 

 to have been entirely different 

 from that which produced the 

 "gypsum" type of Sicily, 

 Louisiana, and other places, for 

 some were undoubtedly pro- 

 duced by a method similar to 

 that which is now producing 

 sulphur in a crater on Kunashiri, 

 the southwestern of the Kurile 

 Islands, nearest Hokkaido. 



In the southwestern part of 

 Kunashiri is Lake Ichibishinai, a crater lake 1 kilometer in diam- 

 eter and 150 meters above the level of the sea. South of this lake, 

 and 7 meters higher in elevation, there is a small circular lake 



806 



Fig. 1. — Sketch map of Hokkaido and 

 the southern part of the Kurile Islands. 



