Sulfur Contents of Volcanic Rocks in Japan

Abstract

Abstract The total sulfur content was determined for 140 samples of Japanese volcanic rock by the mercury(II) thiocyanate photometric method of hydrogen sulfide formed by a wet reduction of the sample by tin(II)–strong phosphoric acid. Though determined values are widely scattered from 5390 down to 10 ppm (or less), the cumulative frequency distribution of the sulfur contents shows lognormality. The geometric and arithmetic means are 26 ppm (mg kg−1) and 116 ppm, respectively. The alkaline rocks have high sulfur contents, the geometric mean of which is 62 ppm. Little significant difference was observed among the rhyolitic rock, the andesite and the trachyte, and the basaltic rock. Japanese and foreign standard rock samples were analyzed for sulfur. Almost all results were in good agreement with those obtained by other authors. In this case foreign standard samples also have higher sulfur contents than those of Japanese samples. The fact that the sulfur contents of Japanese volcanic rocks are lower than the previously accepted values seems to be characteristic of the islands arc of volcanism.