170 JV. L. Boxoen — Crystallization of Hajplobasaltic, 



area DEF all liquid 



ADB liquid D, solid A and solid B 



DBE liquid D - E and solid B 



EBC liquid E, solid B and solid C 



EFC liquid E - F and solid C 



FAC liquid F, solid C and solid A 



FAD liquid D - F and solid A 



Fig. 8. 



Fig. 8. Eutectic system at T° . 



Evidently locating the isotherm DEF fixes all these rela- 

 tions since all the other lines are simply straight lines joining 

 D, E and F with the corners of the triangle. In a system 

 where solid solution occurs the matter is not so simple. Equi- 

 librium at 1230° in the investigated system is shown in fig. 9 

 by means of full lines. DFE is the isotherm of 1230°. The 

 phases present in the various areas are as follows : 



area DFEB all liquid 



EFG liquid E - F and plagioclase K - G 



" ADF liquid D — F and diopside 



" AFG liquid F, plagioclase G and diopside 



" AGC plagioclase G — C and diopside 



