THE GEEAT ERUPTION OF SAKU1ÎA-JIMA IN 1914. 



201 



Sal 

 87.30 



An analysis of this type was kindly made for the writer by 

 Mr. Ohashi, of our Geological Survey, with the following result : 

 Sample taken was 1 gram. 



Norm -P 



Quartz SiO, 46.47 Q 46.47 



Orthoclase K^O'AlO.-eSiO,. .15.79 



Albite Na,0-Al,0-,'6SiO,. . . .^OmI F 40.31- 



Auorthite CaO-AkO^-2SiO,. . 3.98 



Corundum AkO^ 0.52 



Water H,0 0.37 



Cordierite 23IgO-2AlO;-5SiO., 9.57 



Pyrrhotite FesSo 0.77 



Apatite 3CaO-P.,0, 0.19 



Magnetite FeO-Fe,0, 0.42 



Hematite Fe.,0, 0.53 



Ilmenite jPeO-r^O, 0.38 



99.82 



From the norm, ratios are m\en as below : 



Fern 

 11.86 



Sal 



Persalane 



87.30 



Fem 



= 7M> 



11.86 



Alsbachnse 



K,0' + Na.O' 



F 



Columbare 



46.47 



^_6L=4.79<1>1 

 14 13 



40.31 



K.,0' 



= 1.15< — > — 

 3 5 



Tehamose 



28 



0.77< — >-?^ 

 3 5 



CaO' 14 ^ 1 ' 3 Na,0' 39 



The ceramicite is a scale segregate of augite -andésite, and 

 chemically speaking, it represents a series of biotite-granite, quartz- 

 porphyry, rhyolite and quartz-porphyry schist. 



The fleckless barren modification (PL XXII. Fig. 5, and Text-fig. 

 45) contains idiomorphic phenocrysts (1 mm.) of polysynthetic 

 anorthite imbedded in the vacuole-rich glass ground, which contains 

 a few corroded non-pleochroic cordierite (the rather large subangular 



1) Calculated by T. Ogiira. 



